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TDMS Study 05180-07 Pathology Tables

NTP                                    STATISTICAL ANALYSIS OF NON-NEOPLASTIC LESIONS                          REPORT: PEIRPT10     
LAB: Battelle Northwest                                     GALLIUM ARSENIDE                                   DATE: 03/09/99       
EXPERIMENT: 05180 TEST: 07                                                                                     TIME: 14:29:27       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: NO1-ES-25335                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 62033B       
PATHOLOGIST: MILLER, RODNEY                                                                                    CAS: 1303-00-0000    
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    
                                                        2 YEAR CHRONIC MICE                                                         
                                                                                                                                    

               REASONS FOR REMOVAL:    ALL                                                                                          
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       INCLUDE ALL                                                                                  
NTP                                    STATISTICAL ANALYSIS OF NON-NEOPLASTIC LESIONS                          REPORT: PEIRPT10   
LAB: Battelle Northwest                                     GALLIUM ARSENIDE                                   DATE: 03/09/99     
EXPERIMENT: 05180 TEST: 07                                                                                     TIME: 14:29:27     
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                      
CONT: NO1-ES-25335                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 62033B     
PATHOLOGIST: MILLER, RODNEY                                                                                    CAS: 1303-00-0000  



SUMMARY OF STATISTICALLY SIGNIFICANT (P<=.05) RESULTS
IN THE ANALYSIS OF                 GALLIUM ARSENIDE
===============================================================

Male Mice
------------
Organ                                 Morphology
-----                                 ----------
Adrenal Cortex                         Hypertrophy
Harderian Gland                        Hyperplasia
Heart                                  Cardiomyopathy
Larynx: Squamous Epithelium            Hyperplasia
Liver                                  Eosinophilic Focus
Lung                                   Infiltration Cellular Histiocyte
                                       Inflammation Chronic Focal
                                       Inflammation Focal
Lung: Alveolar Epithelium              Hyperplasia
Lung: Alveolus                         Foreign Body
                                       Proteinosis
Lymph Node, Bronchial                  Hyperplasia
Mesentery: Fat                         Necrosis
Preputial Gland                        Inflammation
Testes                                 Atrophy
===============================================================
Female Mice
------------
Organ                                  Morphology
-----                                  ----------
Kidney                                 Nephropathy
Liver                                  Eosinophilic Focus
Lung                                   Infiltration Cellular Histiocyte
                                       Inflammation Chronic Focal
                                       Inflammation Focal
Lung: Alveolar Epithelium              Hyperplasia
Lung: Alveolus                         Foreign Body
                                       Proteinosis
Lymph Node, Bronchial                  Hyperplasia
Mesentery: Fat                         Necrosis
Nose: Olfactory Epithelium             Degeneration Hyaline
Pituitary Gland: Pars Distalis         Hyperplasia
Spleen                                 Hematopoietic Cell Proliferation
                                       Hyperplasia Lymphoid
===============================================================
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 1
                     Statistical Analysis of Non-neoplastic Lesions in        Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Cortex                                                                                                                   |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     4/50 (8%)    10/50 (20%)  7/50 (14%)   4/48 (8%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/49 (0%)    |
|POLY-3 ADJUSTED (b)|     9.1%         21.6%        16.3%        9.0%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     3/35 (9%)    8/38 (21%)   7/34 (21%)   3/34 (9%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     647          609          733 (T)      723         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.293N     P=0.105      P=0.240      P=0.634     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.251N     P=0.086      P=0.243      P=0.642N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.254N     P=0.083      P=0.253      P=0.640     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.253N     P=0.090      P=0.232      P=0.641N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.261N     P=0.087      P=0.237      P=0.638N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.274N     P=0.074      P=0.262      P=0.619     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Cortex                                                                                                                   |
|     Hypertrophy                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     38/50 (76%)  33/50 (66%)  38/50 (76%)  30/48 (63%) |5/50 (10%)   5/50 (10%)   7/50 (14%)   7/49 (14%)   |
|POLY-3 ADJUSTED (b)|     82.7%        71.1%        82.9%        65.0%       |11.2%        11.0%        17.1%        16.8%        |
|TERMINAL (d)       |     33/35 (94%)  29/38 (76%)  30/34 (88%)  25/34 (74%) |5/36 (14%)   5/34 (15%)   6/31 (19%)   5/29 (17%)   |
|FIRST INCIDENCE    |     462          659          504          501         |735 (T)      735 (T)      629          646          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.255N     P=0.053N     P=0.490      P=0.077N    |P=0.144      P=0.596      P=0.277      P=0.249      |
|POLY 3             |     P=0.079N     P=0.128N     P=0.606      P=0.037N*   |P=0.202      P=0.624N     P=0.316      P=0.328      |
|POLY 1.5           |     P=0.107N     P=0.137N     P=0.608      P=0.051N    |P=0.221      P=0.629N     P=0.336      P=0.343      |
|POLY 6             |     P=0.058N     P=0.112N     P=0.626      P=0.025N*   |P=0.185      P=0.620N     P=0.301      P=0.313      |
|LOGISTIC REGRESSION|     P=0.120N     P=0.079N     P=0.540      P=0.051N    |P=0.171      P=0.596      P=0.286      P=0.297      |
|COCH-ARM / FISHERS |     P=0.190N     P=0.189N     P=0.592N     P=0.109N    |P=0.249      P=0.630N     P=0.380      P=0.365      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 2
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    1/47 (2%)   |1/50 (2%)    2/49 (4%)    1/50 (2%)    2/49 (4%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         2.3%        |2.2%         4.5%         2.4%         4.8%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    1/34 (3%)   |1/36 (3%)    2/34 (6%)    0/31 (0%)    2/29 (7%)    |
|FIRST INCIDENCE    |     ---          ---          ---          733 (T)     |735 (T)      735 (T)      659          735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.178      (e)          (e)          P=0.494     |P=0.403      P=0.480      P=0.726      P=0.424      |
|POLY 3             |     P=0.182      (e)          (e)          P=0.498     |P=0.444      P=0.496      P=0.740      P=0.471      |
|POLY 1.5           |     P=0.181      (e)          (e)          P=0.496     |P=0.457      P=0.494      P=0.746      P=0.480      |
|POLY 6             |     P=0.183      (e)          (e)          P=0.501     |P=0.431      P=0.499      P=0.734      P=0.462      |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          P=0.494     |P=0.433      P=0.480      P=0.755      P=0.424      |
|COCH-ARM / FISHERS |     P=0.178      (e)          (e)          P=0.485     |P=0.475      P=0.492      P=0.753N     P=0.492      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Bone                                                                                                                             |
|     Fibrous Osteodystrophy                                                                                                      |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/49 (2%)    2/50 (4%)    2/50 (4%)    0/50 (0%)   |21/50 (42%)  24/50 (48%)  14/50 (28%)  18/50 (36%)  |
|POLY-3 ADJUSTED (b)|     2.3%         4.4%         4.7%         0.0%        |44.8%        52.2%        34.0%        42.1%        |
|TERMINAL (d)       |     1/34 (3%)    2/38 (5%)    2/34 (6%)    0/34 (0%)   |16/36 (44%)  20/34 (59%)  11/31 (36%)  16/29 (55%)  |
|FIRST INCIDENCE    |     733 (T)      733 (T)      733 (T)      ---         |237          659          560          529          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.278N     P=0.539      P=0.500      P=0.500N    |P=0.374N     P=0.285      P=0.235N     P=0.513      |
|POLY 3             |     P=0.256N     P=0.524      P=0.501      P=0.490N    |P=0.220N     P=0.307      P=0.204N     P=0.481N     |
|POLY 1.5           |     P=0.256N     P=0.519      P=0.504      P=0.491N    |P=0.174N     P=0.307      P=0.167N     P=0.425N     |
|POLY 6             |     P=0.258N     P=0.529      P=0.496      P=0.490N    |P=0.279N     P=0.308      P=0.241N     P=0.544N     |
|LOGISTIC REGRESSION|     P=0.278N     P=0.539      P=0.500      (e)         |P=0.207N     P=0.346      P=0.152N     P=0.401N     |
|COCH-ARM / FISHERS |     P=0.260N     P=0.508      P=0.508      P=0.495N    |P=0.122N     P=0.344      P=0.104N     P=0.341N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 3
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Bone Marrow                                                                                                                      |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/49 (4%)    3/50 (6%)    2/50 (4%)    3/48 (6%)   |2/50 (4%)    1/50 (2%)    2/50 (4%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     4.5%         6.5%         4.6%         6.7%        |4.4%         2.2%         4.8%         2.4%         |
|TERMINAL (d)       |     0/34 (0%)    2/38 (5%)    1/34 (3%)    0/34 (0%)   |0/36 (0%)    1/34 (3%)    1/31 (3%)    0/29 (0%)    |
|FIRST INCIDENCE    |     462          729          639          555         |439          735 (T)      421          710          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.473      P=0.533      P=0.686      P=0.506     |P=0.531N     P=0.518N     P=0.649      P=0.542N     |
|POLY 3             |     P=0.481      P=0.517      P=0.687      P=0.507     |P=0.512N     P=0.503N     P=0.658      P=0.527N     |
|POLY 1.5           |     P=0.480      P=0.517      P=0.693      P=0.504     |P=0.498N     P=0.503N     P=0.670      P=0.516N     |
|POLY 6             |     P=0.482      P=0.519      P=0.680      P=0.509     |P=0.526N     P=0.502N     P=0.648      P=0.539N     |
|LOGISTIC REGRESSION|     P=0.432      P=0.447      P=0.690      P=0.355     |P=0.455N     P=0.486N     P=0.605N     P=0.476N     |
|COCH-ARM / FISHERS |     P=0.470      P=0.510      P=0.684N     P=0.490     |P=0.479N     P=0.500N     P=0.691N     P=0.500N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Brain: Meninges                                                                                                                  |
|     Infiltration Cellular Mononuclear Cell                                                                                      |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    1/50 (2%)    0/49 (0%)   |2/50 (4%)    5/50 (10%)   3/50 (6%)    3/50 (6%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         2.3%         0.0%        |4.5%         11.0%        7.3%         7.1%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    1/34 (3%)    0/34 (0%)   |2/36 (6%)    4/34 (12%)   2/31 (7%)    2/29 (7%)    |
|FIRST INCIDENCE    |     ---          ---          733 (T)      ---         |735 (T)      715          659          714          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.638      (e)          P=0.494      (e)         |P=0.516      P=0.200      P=0.432      P=0.409      |
|POLY 3             |     P=0.657      (e)          P=0.496      (e)         |P=0.560N     P=0.221      P=0.458      P=0.472      |
|POLY 1.5           |     P=0.655      (e)          P=0.498      (e)         |P=0.541N     P=0.218      P=0.471      P=0.484      |
|POLY 6             |     P=0.658      (e)          P=0.493      (e)         |P=0.561      P=0.224      P=0.447      P=0.459      |
|LOGISTIC REGRESSION|     (e)          (e)          P=0.494      (e)         |P=0.556      P=0.213      P=0.448      P=0.440      |
|COCH-ARM / FISHERS |     P=0.646      (e)          P=0.500      (e)         |P=0.515N     P=0.218      P=0.500      P=0.500      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 4
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Epididymis                                                                                                                       |
|     Granuloma Sperm                                                                                                             |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/50 (4%)    0/50 (0%)    1/49 (2%)   |                                                    |
|POLY-3 ADJUSTED (b)|     0.0%         4.4%         0.0%         2.2%        |                                                    |
|TERMINAL (d)       |     0/35 (0%)    2/38 (5%)    0/34 (0%)    1/34 (3%)   |                                                    |
|FIRST INCIDENCE    |     ---          733 (T)      ---          733 (T)     |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.626      P=0.257      (e)          P=0.494     |                                                    |
|POLY 3             |     P=0.644N     P=0.247      (e)          P=0.504     |                                                    |
|POLY 1.5           |     P=0.644N     P=0.245      (e)          P=0.503     |                                                    |
|POLY 6             |     P=0.644N     P=0.251      (e)          P=0.505     |                                                    |
|LOGISTIC REGRESSION|     (e)          P=0.257      (e)          P=0.494     |                                                    |
|COCH-ARM / FISHERS |     P=0.640      P=0.247      (e)          P=0.495     |                                                    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Epididymis                                                                                                                       |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    1/50 (2%)    0/50 (0%)    0/49 (0%)   |                                                    |
|POLY-3 ADJUSTED (b)|     4.5%         2.2%         0.0%         0.0%        |                                                    |
|TERMINAL (d)       |     1/35 (3%)    1/38 (3%)    0/34 (0%)    0/34 (0%)   |                                                    |
|FIRST INCIDENCE    |     462          733 (T)      ---          ---         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.111N     P=0.476N     P=0.243N     P=0.241N    |                                                    |
|POLY 3             |     P=0.109N     P=0.490N     P=0.246N     P=0.236N    |                                                    |
|POLY 1.5           |     P=0.108N     P=0.492N     P=0.242N     P=0.237N    |                                                    |
|POLY 6             |     P=0.111N     P=0.487N     P=0.250N     P=0.237N    |                                                    |
|LOGISTIC REGRESSION|     P=0.113N     P=0.548N     P=0.245N     P=0.298N    |                                                    |
|COCH-ARM / FISHERS |     P=0.106N     P=0.500N     P=0.247N     P=0.253N    |                                                    |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 5
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Eye                                                                                                                              |
|     Degeneration                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/2 (0%)     1/1 (100%)   0/0 (0%)     2/4 (50%)   |0/1 (0%)     0/0 (0%)     1/2 (50%)    0/1 (0%)     |
|POLY-3 ADJUSTED (b)|     0.0%         100.0%       0.0%         50.2%       |0.0%         0.0%         50.0%        0.0%         |
|TERMINAL (d)       |     0/2 (0%)     0/0 (0%)     0/0 (0%)     2/3 (67%)   |0/0 (0%)     0/0 (0%)     1/2 (50%)    0/1 (0%)     |
|FIRST INCIDENCE    |     ---          609          ---          733 (T)     |---          ---          735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.360      P=0.527      (e)          P=0.309     |P=0.638N     (e)          P=1.000      (e)          |
|POLY 3             |     (e)          P=1.000      (e)          P=0.385     |(e)          (e)          P=0.677      (e)          |
|POLY 1.5           |     (e)          P=1.000      (e)          P=0.386     |(e)          (e)          P=0.649      (e)          |
|POLY 6             |     (e)          P=1.000      (e)          P=0.383     |(e)          (e)          P=0.714      (e)          |
|LOGISTIC REGRESSION|     P=0.233      (e)          (e)          P=0.309     |(e)          (e)          P=1.000      (e)          |
|COCH-ARM / FISHERS |     P=0.441      P=0.333      (e)          P=0.400     |P=0.793      (e)          P=0.667      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Harderian Gland                                                                                                                  |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/47 (2%)    1/48 (2%)    10/49 (20%)  1/48 (2%)   |0/5 (0%)     0/4 (0%)     0/3 (0%)     0/2 (0%)     |
|POLY-3 ADJUSTED (b)|     2.3%         2.3%         23.3%        2.3%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    1/37 (3%)    9/34 (27%)   1/33 (3%)   |0/3 (0%)     0/3 (0%)     0/2 (0%)     0/2 (0%)     |
|FIRST INCIDENCE    |     699          733 (T)      729          733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.276      P=0.746N     P=0.005 **   P=0.754     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.312      P=0.755N     P=0.004 **   P=0.758N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.317      P=0.756N     P=0.004 **   P=0.757N    |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.302      P=0.754N     P=0.003 **   P=0.760N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.297      P=0.757N     P=0.004 **   P=0.759N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.326      P=0.747N     P=0.005 **   P=0.747N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 6
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Heart                                                                                                                            |
|     Cardiomyopathy                                                                                                              |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     48/50 (96%)  50/50 (100%) 49/50 (98%)  47/50 (94%) |49/50 (98%)  48/50 (96%)  47/50 (94%)  47/50 (94%)  |
|POLY-3 ADJUSTED (b)|     99.5%        100.0%       98.0%        95.2%       |99.9%        97.9%        97.0%        97.6%        |
|TERMINAL (d)       |     35/35 (100%) 38/38 (100%) 33/34 (97%)  33/34 (97%) |36/36 (100%) 33/34 (97%)  30/31 (97%)  29/29 (100%) |
|FIRST INCIDENCE    |     457          473          232          406         |439          302          281          412          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.464      P=0.424N     P=0.402      P=0.548N    |P=0.110      P=0.529      P=0.254      P=0.160      |
|POLY 3             |     P=0.044N*    P=0.998      P=0.604N     P=0.223N    |P=0.327N     P=0.511N     P=0.339N     P=0.430N     |
|POLY 1.5           |     P=0.050N     P=0.826      P=0.686N     P=0.251N    |P=0.214N     P=0.544N     P=0.290N     P=0.301N     |
|POLY 6             |     P=0.052N     P=1.000      P=0.533N     P=0.229N    |P=0.488N     P=0.500N     P=0.420N     P=0.666N     |
|LOGISTIC REGRESSION|     P=0.109N     (e)          P=0.569      P=0.308N    |P=0.228N     P=0.641N     P=0.528N     P=0.357N     |
|COCH-ARM / FISHERS |     P=0.185N     P=0.247      P=0.500      P=0.500N    |P=0.231N     P=0.500N     P=0.309N     P=0.309N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Heart: Atrium                                                                                                                    |
|     Thrombosis                                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/50 (0%)    0/50 (0%)    0/50 (0%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     4.5%         0.0%         0.0%         0.0%        |0.0%         0.0%         0.0%         2.3%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     561          ---          ---          ---         |---          ---          ---          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.166N     P=0.229N     P=0.251N     P=0.237N    |P=0.182      (e)          (e)          P=0.492      |
|POLY 3             |     P=0.166N     P=0.231N     P=0.245N     P=0.235N    |P=0.180      (e)          (e)          P=0.491      |
|POLY 1.5           |     P=0.164N     P=0.232N     P=0.241N     P=0.234N    |P=0.183      (e)          (e)          P=0.495      |
|POLY 6             |     P=0.169N     P=0.229N     P=0.250N     P=0.237N    |P=0.176      (e)          (e)          P=0.486      |
|LOGISTIC REGRESSION|     P=0.167N     P=0.266N     P=0.240N     P=0.261N    |P=0.163      (e)          (e)          P=0.488      |
|COCH-ARM / FISHERS |     P=0.160N     P=0.247N     P=0.247N     P=0.247N    |P=0.186      (e)          (e)          P=0.500      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 7
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Intestine Small, Ileum: Peyer's Patch                                                                                            |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/44 (0%)    0/47 (0%)    1/45 (2%)    0/42 (0%)   |1/48 (2%)    0/47 (0%)    2/49 (4%)    1/45 (2%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         2.5%         0.0%        |2.3%         0.0%         5.0%         2.6%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    1/34 (3%)    0/34 (0%)   |1/36 (3%)    0/34 (0%)    1/31 (3%)    1/29 (3%)    |
|FIRST INCIDENCE    |     ---          ---          733 (T)      ---         |735 (T)      ---          645          735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.638      (e)          P=0.494      (e)         |P=0.368      P=0.511N     P=0.448      P=0.713      |
|POLY 3             |     P=0.655      (e)          P=0.501      (e)         |P=0.368      P=0.499N     P=0.468      P=0.729      |
|POLY 1.5           |     P=0.651      (e)          P=0.504      (e)         |P=0.382      P=0.501N     P=0.479      P=0.735      |
|POLY 6             |     P=0.656      (e)          P=0.498      (e)         |P=0.357      P=0.498N     P=0.460      P=0.723      |
|LOGISTIC REGRESSION|     (e)          (e)          P=0.494      (e)         |P=0.382      (e)          P=0.482      P=0.713      |
|COCH-ARM / FISHERS |     P=0.640      (e)          P=0.506      (e)         |P=0.408      P=0.505N     P=0.508      P=0.736      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Intestine Small, Jejunum: Peyer's Patch                                                                                          |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/44 (2%)    0/48 (0%)    1/45 (2%)    1/43 (2%)   |2/48 (4%)    1/47 (2%)    0/49 (0%)    0/43 (0%)    |
|POLY-3 ADJUSTED (b)|     2.5%         0.0%         2.5%         2.5%        |4.5%         2.3%         0.0%         0.0%         |
|TERMINAL (d)       |     1/35 (3%)    0/38 (0%)    1/34 (3%)    0/34 (0%)   |2/36 (6%)    1/34 (3%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     733 (T)      ---          733 (T)      723         |735 (T)      735 (T)      ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.457      P=0.484N     P=0.755      P=0.757N    |P=0.128N     P=0.520N     P=0.272N     P=0.287N     |
|POLY 3             |     P=0.463      P=0.481N     P=0.759N     P=0.759N    |P=0.123N     P=0.498N     P=0.260N     P=0.274N     |
|POLY 1.5           |     P=0.461      P=0.480N     P=0.756N     P=0.759N    |P=0.119N     P=0.501N     P=0.252N     P=0.270N     |
|POLY 6             |     P=0.463      P=0.482N     P=0.759      P=0.759N    |P=0.126N     P=0.496N     P=0.267N     P=0.277N     |
|LOGISTIC REGRESSION|     P=0.457      (e)          P=0.755      P=0.762N    |P=0.128N     P=0.520N     (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.453      P=0.478N     P=0.747N     P=0.747     |P=0.111N     P=0.508N     P=0.242N     P=0.275N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 8
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    3/48 (6%)    2/49 (4%)    4/47 (9%)   |1/50 (2%)    1/50 (2%)    1/50 (2%)    1/48 (2%)    |
|POLY-3 ADJUSTED (b)|     4.6%         6.8%         4.7%         9.2%        |2.2%         2.2%         2.5%         2.4%         |
|TERMINAL (d)       |     2/35 (6%)    3/36 (8%)    2/34 (6%)    2/34 (6%)   |0/36 (0%)    0/34 (0%)    1/31 (3%)    1/29 (3%)    |
|FIRST INCIDENCE    |     733 (T)      733 (T)      733 (T)      665         |694          715          735 (T)      735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.284      P=0.513      P=0.685      P=0.333     |P=0.569      P=0.755N     P=0.725      P=0.724      |
|POLY 3             |     P=0.299      P=0.500      P=0.683      P=0.334     |P=0.591      P=0.759N     P=0.737      P=0.740      |
|POLY 1.5           |     P=0.296      P=0.496      P=0.685      P=0.328     |P=0.601      P=0.760N     P=0.745      P=0.745      |
|POLY 6             |     P=0.302      P=0.506      P=0.680      P=0.340     |P=0.580      P=0.758N     P=0.730      P=0.734      |
|LOGISTIC REGRESSION|     P=0.295      P=0.513      P=0.685      P=0.332     |P=0.590      P=0.762N     P=0.742      P=0.744      |
|COCH-ARM / FISHERS |     P=0.283      P=0.480      P=0.684      P=0.310     |P=0.615      P=0.753N     P=0.753N     P=0.742      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney                                                                                                                           |
|     Glomerulosclerosis                                                                                                          |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/49 (0%)    0/48 (0%)   |2/50 (4%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |4.4%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |1/36 (3%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |237          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.173N     P=0.248N     P=0.256N     P=0.263N     |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.165N     P=0.240N     P=0.265N     P=0.256N     |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.162N     P=0.241N     P=0.256N     P=0.249N     |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.168N     P=0.238N     P=0.272N     P=0.264N     |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.145N     P=0.171N     P=0.132N     P=0.221N     |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.160N     P=0.247N     P=0.247N     P=0.247N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 9
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney                                                                                                                           |
|     Hydronephrosis                                                                                                              |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    3/50 (6%)    2/49 (4%)    3/48 (6%)   |1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     4.5%         6.5%         4.6%         6.7%        |2.2%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    2/38 (5%)    1/34 (3%)    2/34 (6%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     561          617          504          659         |729          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.463      P=0.528      P=0.681      P=0.497     |P=0.381N     P=0.516N     P=0.534N     P=0.547N     |
|POLY 3             |     P=0.474      P=0.518      P=0.684      P=0.501     |P=0.358N     P=0.498N     P=0.520N     P=0.513N     |
|POLY 1.5           |     P=0.473      P=0.514      P=0.686      P=0.497     |P=0.356N     P=0.500N     P=0.513N     P=0.507N     |
|POLY 6             |     P=0.474      P=0.524      P=0.681      P=0.503     |P=0.360N     P=0.497N     P=0.526N     P=0.519N     |
|LOGISTIC REGRESSION|     P=0.438      P=0.475      P=0.680      P=0.460     |P=0.372N     P=0.498N     P=0.529N     P=0.524N     |
|COCH-ARM / FISHERS |     P=0.462      P=0.500      P=0.684      P=0.480     |P=0.351N     P=0.500N     P=0.500N     P=0.500N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney                                                                                                                           |
|     Metaplasia Osseous                                                                                                          |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    1/50 (2%)    4/49 (8%)    0/48 (0%)   |2/50 (4%)    3/50 (6%)    1/50 (2%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.2%         9.4%         0.0%        |4.5%         6.6%         2.5%         2.4%         |
|TERMINAL (d)       |     0/35 (0%)    1/38 (3%)    3/34 (9%)    0/34 (0%)   |2/36 (6%)    2/34 (6%)    1/31 (3%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          733 (T)      692          ---         |735 (T)      715          735 (T)      646          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.544      P=0.516      P=0.060      (e)         |P=0.295N     P=0.482      P=0.552N     P=0.553N     |
|POLY 3             |     P=0.584      P=0.509      P=0.056      (e)         |P=0.256N     P=0.505      P=0.535N     P=0.519N     |
|POLY 1.5           |     P=0.578      P=0.507      P=0.057      (e)         |P=0.246N     P=0.501      P=0.523N     P=0.511N     |
|POLY 6             |     P=0.587      P=0.512      P=0.056      (e)         |P=0.266N     P=0.509      P=0.545N     P=0.528N     |
|LOGISTIC REGRESSION|     P=0.561      P=0.516      P=0.057      (e)         |P=0.263N     P=0.502      P=0.552N     P=0.512N     |
|COCH-ARM / FISHERS |     P=0.554      P=0.500      P=0.056      (e)         |P=0.232N     P=0.500      P=0.500N     P=0.500N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 10
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney                                                                                                                           |
|     Nephropathy                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     48/50 (96%)  49/50 (98%)  45/49 (92%)  47/48 (98%) |43/50 (86%)  44/50 (88%)  40/50 (80%)  36/50 (72%)  |
|POLY-3 ADJUSTED (b)|     99.5%        99.4%        97.0%        97.9%       |88.7%        92.0%        84.8%        77.6%        |
|TERMINAL (d)       |     35/35 (100%) 38/38 (100%) 34/34 (100%) 33/34 (97%) |32/36 (89%)  31/34 (91%)  26/31 (84%)  24/29 (83%)  |
|FIRST INCIDENCE    |     457          473          393          501         |439          533          239          365          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.470      P=0.346N     P=0.451N     P=0.550N    |P=0.496N     P=0.393      P=0.384      P=0.559      |
|POLY 3             |     P=0.282N     P=0.994N     P=0.413N     P=0.595N    |P=0.024N*    P=0.419      P=0.391N     P=0.106N     |
|POLY 1.5           |     P=0.379N     P=0.912N     P=0.289N     P=0.676N    |P=0.014N*    P=0.418      P=0.337N     P=0.078N     |
|POLY 6             |     P=0.197N     P=1.000N     P=0.820N     P=0.525N    |P=0.051N     P=0.438      P=0.456N     P=0.163N     |
|LOGISTIC REGRESSION|     P=0.357N     P=0.804N     P=0.305N     P=0.674N    |P=0.027N*    P=0.488      P=0.389N     P=0.093N     |
|COCH-ARM / FISHERS |     P=0.574      P=0.500      P=0.329N     P=0.515     |P=0.018N*    P=0.500      P=0.298N     P=0.070N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Capsule                                                                                                                  |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    1/50 (2%)    2/49 (4%)    0/48 (0%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.2%         4.7%         0.0%        |0.0%         0.0%         0.0%         2.4%         |
|TERMINAL (d)       |     0/35 (0%)    1/38 (3%)    2/34 (6%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          733 (T)      733 (T)      ---         |---          ---          ---          710          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.608N     P=0.516      P=0.232      (e)         |P=0.171      (e)          (e)          P=0.478      |
|POLY 3             |     P=0.584N     P=0.509      P=0.230      (e)         |P=0.178      (e)          (e)          P=0.488      |
|POLY 1.5           |     P=0.587N     P=0.507      P=0.232      (e)         |P=0.182      (e)          (e)          P=0.493      |
|POLY 6             |     P=0.582N     P=0.512      P=0.228      (e)         |P=0.174      (e)          (e)          P=0.482      |
|LOGISTIC REGRESSION|     (e)          P=0.516      P=0.232      (e)         |P=0.179      (e)          (e)          P=0.491      |
|COCH-ARM / FISHERS |     P=0.599N     P=0.500      P=0.242      (e)         |P=0.186      (e)          (e)          P=0.500      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 11
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Cortex                                                                                                                   |
|     Cyst                                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    4/50 (8%)    0/49 (0%)    2/48 (4%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     4.6%         8.7%         0.0%         4.5%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     2/35 (6%)    4/38 (11%)   0/34 (0%)    2/34 (6%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     733 (T)      733 (T)      ---          733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.335N     P=0.375      P=0.245N     P=0.685     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.316N     P=0.358      P=0.244N     P=0.691N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.317N     P=0.353      P=0.242N     P=0.693     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.316N     P=0.365      P=0.246N     P=0.688N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.335N     P=0.375      (e)          P=0.685     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.324N     P=0.339      P=0.253N     P=0.676     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/50 (0%)    3/49 (6%)    1/48 (2%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     4.6%         0.0%         7.1%         2.3%        |0.0%         0.0%         0.0%         2.4%         |
|TERMINAL (d)       |     2/35 (6%)    0/38 (0%)    3/34 (9%)    1/34 (3%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     733 (T)      ---          733 (T)      733 (T)     |---          ---          ---          717          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.535      P=0.220N     P=0.487      P=0.510N    |P=0.170      (e)          (e)          P=0.466      |
|POLY 3             |     P=0.559      P=0.227N     P=0.486      P=0.497N    |P=0.178      (e)          (e)          P=0.488      |
|POLY 1.5           |     P=0.556      P=0.230N     P=0.489      P=0.501N    |P=0.182      (e)          (e)          P=0.493      |
|POLY 6             |     P=0.558      P=0.224N     P=0.482      P=0.494N    |P=0.173      (e)          (e)          P=0.482      |
|LOGISTIC REGRESSION|     P=0.535      (e)          P=0.487      P=0.510N    |P=0.176      (e)          (e)          P=0.486      |
|COCH-ARM / FISHERS |     P=0.546      P=0.247N     P=0.490      P=0.515N    |P=0.186      (e)          (e)          P=0.500      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 12
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Larynx                                                                                                                           |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    1/50 (2%)    1/48 (2%)    0/48 (0%)   |2/50 (4%)    2/50 (4%)    2/50 (4%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.2%         2.4%         0.0%        |4.3%         4.3%         4.8%         2.3%         |
|TERMINAL (d)       |     0/35 (0%)    1/38 (3%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          733 (T)      504          ---         |237          533          483          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.542N     P=0.516      P=0.496      (e)         |P=0.397N     P=0.679N     P=0.667      P=0.510N     |
|POLY 3             |     P=0.534N     P=0.509      P=0.493      (e)         |P=0.403N     P=0.693N     P=0.659      P=0.526N     |
|POLY 1.5           |     P=0.537N     P=0.507      P=0.493      (e)         |P=0.388N     P=0.691      P=0.669      P=0.516N     |
|POLY 6             |     P=0.532N     P=0.512      P=0.492      (e)         |P=0.418N     P=0.689N     P=0.651      P=0.537N     |
|LOGISTIC REGRESSION|     P=0.590N     P=0.516      P=0.453      (e)         |P=0.331N     P=0.652N     P=0.511N     P=0.470N     |
|COCH-ARM / FISHERS |     P=0.546N     P=0.500      P=0.490      (e)         |P=0.366N     P=0.691N     P=0.691N     P=0.500N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Larynx: Squamous Epithelium                                                                                                      |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     11/50 (22%)  13/50 (26%)  11/48 (23%)  5/48 (10%)  |11/50 (22%)  9/50 (18%)   7/50 (14%)   7/50 (14%)   |
|POLY-3 ADJUSTED (b)|     23.8%        28.2%        26.2%        10.9%       |23.2%        19.4%        16.2%        16.4%        |
|TERMINAL (d)       |     6/35 (17%)   10/38 (26%)  10/34 (29%)  1/34 (3%)   |5/36 (14%)   6/34 (18%)   3/31 (10%)   5/29 (17%)   |
|FIRST INCIDENCE    |     54           710          609          501         |237          533          365          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.059N     P=0.500      P=0.564      P=0.102N    |P=0.307N     P=0.426N     P=0.322N     P=0.354N     |
|POLY 3             |     P=0.039N*    P=0.404      P=0.496      P=0.086N    |P=0.243N     P=0.423N     P=0.286N     P=0.292N     |
|POLY 1.5           |     P=0.042N*    P=0.405      P=0.514      P=0.091N    |P=0.214N     P=0.422N     P=0.264N     P=0.262N     |
|POLY 6             |     P=0.037N*    P=0.403      P=0.473      P=0.083N    |P=0.278N     P=0.427N     P=0.307N     P=0.330N     |
|LOGISTIC REGRESSION|     P=0.052N     P=0.380      P=0.553      P=0.177N    |P=0.150N     P=0.394N     P=0.124N     P=0.188N     |
|COCH-ARM / FISHERS |     P=0.049N*    P=0.408      P=0.553      P=0.100N    |P=0.176N     P=0.402N     P=0.218N     P=0.218N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 13
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Basophilic Focus                                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    1/50 (2%)    2/50 (4%)    2/50 (4%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.2%         4.7%         4.4%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    1/38 (3%)    2/34 (6%)    2/34 (6%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          733 (T)      733 (T)      733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.146      P=0.516      P=0.232      P=0.232     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.168      P=0.509      P=0.232      P=0.243     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.169      P=0.507      P=0.235      P=0.242     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.166      P=0.512      P=0.229      P=0.242     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     (e)          P=0.516      P=0.232      P=0.232     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.164      P=0.500      P=0.247      P=0.247     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Clear Cell Focus                                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/50 (4%)    2/50 (4%)    1/50 (2%)   |1/50 (2%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         4.4%         4.7%         2.2%        |2.2%         0.0%         2.5%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    1/38 (3%)    2/34 (6%)    1/34 (3%)   |1/36 (3%)    0/34 (0%)    1/31 (3%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          715          733 (T)      733 (T)     |735 (T)      ---          735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.501      P=0.263      P=0.232      P=0.494     |P=0.510N     P=0.511N     P=0.728      P=0.543N     |
|POLY 3             |     P=0.533      P=0.248      P=0.232      P=0.505     |P=0.482N     P=0.498N     P=0.738      P=0.513N     |
|POLY 1.5           |     P=0.532      P=0.245      P=0.235      P=0.505     |P=0.474N     P=0.500N     P=0.746      P=0.507N     |
|POLY 6             |     P=0.531      P=0.251      P=0.229      P=0.505     |P=0.491N     P=0.497N     P=0.731      P=0.519N     |
|LOGISTIC REGRESSION|     P=0.513      P=0.250      P=0.232      P=0.494     |P=0.510N     (e)          P=0.728      (e)          |
|COCH-ARM / FISHERS |     P=0.523      P=0.247      P=0.247      P=0.500     |P=0.464N     P=0.500N     P=0.753N     P=0.500N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 14
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Eosinophilic Focus                                                                                                          |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     11/50 (22%)  14/50 (28%)  14/50 (28%)  19/50 (38%) |5/50 (10%)   15/50 (30%)  11/50 (22%)  14/50 (28%)  |
|POLY-3 ADJUSTED (b)|     25.0%        30.4%        32.2%        41.7%       |11.1%        32.4%        26.9%        32.2%        |
|TERMINAL (d)       |     10/35 (29%)  11/38 (29%)  11/34 (32%)  15/34 (44%) |4/36 (11%)   11/34 (32%)  8/31 (26%)   10/29 (35%)  |
|FIRST INCIDENCE    |     699          710          586          591         |639          533          659          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.039 *    P=0.419      P=0.295      P=0.056     |P=0.042 *    P=0.012 *    P=0.049 *    P=0.008 **   |
|POLY 3             |     P=0.058      P=0.369      P=0.306      P=0.071     |P=0.078      P=0.012 *    P=0.052      P=0.013 *    |
|POLY 1.5           |     P=0.060      P=0.357      P=0.315      P=0.070     |P=0.092      P=0.011 *    P=0.062      P=0.015 *    |
|POLY 6             |     P=0.055      P=0.388      P=0.296      P=0.071     |P=0.066      P=0.012 *    P=0.045 *    P=0.011 *    |
|LOGISTIC REGRESSION|     P=0.049 *    P=0.397      P=0.276      P=0.067     |P=0.077      P=0.012 *    P=0.048 *    P=0.016 *    |
|COCH-ARM / FISHERS |     P=0.059      P=0.322      P=0.322      P=0.063     |P=0.118      P=0.011 *    P=0.086      P=0.020 *    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hematopoietic Cell Proliferation                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    1/50 (2%)    2/50 (4%)    2/50 (4%)   |3/50 (6%)    4/50 (8%)    5/50 (10%)   5/50 (10%)   |
|POLY-3 ADJUSTED (b)|     6.7%         2.2%         4.5%         4.4%        |6.6%         8.7%         11.7%        11.6%        |
|TERMINAL (d)       |     1/35 (3%)    1/38 (3%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    1/34 (3%)    2/31 (7%)    1/29 (3%)    |
|FIRST INCIDENCE    |     561          733 (T)      232          555         |639          644          365          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.565N     P=0.289N     P=0.516N     P=0.503N    |P=0.228      P=0.512      P=0.297      P=0.298      |
|POLY 3             |     P=0.557N     P=0.295N     P=0.504N     P=0.491N    |P=0.254      P=0.507      P=0.322      P=0.329      |
|POLY 1.5           |     P=0.554N     P=0.297N     P=0.499N     P=0.491N    |P=0.271      P=0.502      P=0.334      P=0.341      |
|POLY 6             |     P=0.561N     P=0.293N     P=0.511N     P=0.492N    |P=0.235      P=0.512      P=0.309      P=0.316      |
|LOGISTIC REGRESSION|     P=0.578      P=0.318N     P=0.524N     P=0.539N    |P=0.321      P=0.502      P=0.448      P=0.373      |
|COCH-ARM / FISHERS |     P=0.555N     P=0.309N     P=0.500N     P=0.500N    |P=0.292      P=0.500      P=0.357      P=0.357      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 15
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hyperplasia Lymphoid                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)   |1/50 (2%)    3/50 (6%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |2.2%         6.6%         2.5%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    2/34 (6%)    1/31 (3%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |694          729          735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.177N     P=0.293      P=0.725      P=0.521N     |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.154N     P=0.308      P=0.737      P=0.513N     |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.147N     P=0.306      P=0.745      P=0.508N     |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.162N     P=0.309      P=0.730      P=0.520N     |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.162N     P=0.309      P=0.742      P=0.501N     |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.137N     P=0.309      P=0.753N     P=0.500N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    3/50 (6%)    1/50 (2%)    0/50 (0%)   |3/50 (6%)    1/50 (2%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     4.6%         6.5%         2.3%         0.0%        |6.7%         2.2%         2.4%         0.0%         |
|TERMINAL (d)       |     2/35 (6%)    2/38 (5%)    0/34 (0%)    0/34 (0%)   |2/36 (6%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     733 (T)      715          502          ---         |729          701          659          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.085N     P=0.542      P=0.504N     P=0.245N    |P=0.122N     P=0.321N     P=0.365N     P=0.165N     |
|POLY 3             |     P=0.076N     P=0.521      P=0.502N     P=0.232N    |P=0.105N     P=0.301N     P=0.339N     P=0.130N     |
|POLY 1.5           |     P=0.076N     P=0.516      P=0.500N     P=0.232N    |P=0.099N     P=0.304N     P=0.328N     P=0.125N     |
|POLY 6             |     P=0.077N     P=0.528      P=0.504N     P=0.231N    |P=0.110N     P=0.297N     P=0.348N     P=0.136N     |
|LOGISTIC REGRESSION|     P=0.078N     P=0.534      P=0.501N     (e)         |P=0.102N     P=0.299N     P=0.339N     P=0.148N     |
|COCH-ARM / FISHERS |     P=0.078N     P=0.500      P=0.500N     P=0.247N    |P=0.093N     P=0.309N     P=0.309N     P=0.121N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 16
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Necrosis                                                                                                                    |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     10/50 (20%)  6/50 (12%)   5/50 (10%)   4/50 (8%)   |3/50 (6%)    4/50 (8%)    7/50 (14%)   5/50 (10%)   |
|POLY-3 ADJUSTED (b)|     22.1%        12.8%        11.4%        8.7%        |6.6%         8.8%         16.4%        11.6%        |
|TERMINAL (d)       |     4/35 (11%)   4/38 (11%)   3/34 (9%)    1/34 (3%)   |2/36 (6%)    1/34 (3%)    2/31 (7%)    2/29 (7%)    |
|FIRST INCIDENCE    |     457          473          502          561         |533          688          483          464          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.100N     P=0.177N     P=0.164N     P=0.089N    |P=0.186      P=0.496      P=0.127      P=0.274      |
|POLY 3             |     P=0.076N     P=0.182N     P=0.142N     P=0.066N    |P=0.216      P=0.503      P=0.133      P=0.325      |
|POLY 1.5           |     P=0.075N     P=0.187N     P=0.136N     P=0.067N    |P=0.236      P=0.499      P=0.140      P=0.339      |
|POLY 6             |     P=0.079N     P=0.177N     P=0.151N     P=0.065N    |P=0.196      P=0.507      P=0.130      P=0.310      |
|LOGISTIC REGRESSION|     P=0.077N     P=0.220N     P=0.131N     P=0.081N    |P=0.278      P=0.501      P=0.197      P=0.373      |
|COCH-ARM / FISHERS |     P=0.075N     P=0.207N     P=0.131N     P=0.074N    |P=0.260      P=0.500      P=0.159      P=0.357      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Hemorrhage                                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     5/50 (10%)   6/50 (12%)   6/50 (12%)   3/50 (6%)   |9/50 (18%)   6/50 (12%)   5/50 (10%)   5/50 (10%)   |
|POLY-3 ADJUSTED (b)|     11.4%        13.1%        13.7%        6.7%        |19.5%        13.2%        12.2%        11.4%        |
|TERMINAL (d)       |     5/35 (14%)   6/38 (16%)   4/34 (12%)   3/34 (9%)   |6/36 (17%)   5/34 (15%)   4/31 (13%)   1/29 (3%)    |
|FIRST INCIDENCE    |     733 (T)      733 (T)      609          733 (T)     |533          688          645          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.283N     P=0.558      P=0.480      P=0.371N    |P=0.298N     P=0.319N     P=0.283N     P=0.297N     |
|POLY 3             |     P=0.242N     P=0.531      P=0.497      P=0.343N    |P=0.221N     P=0.297N     P=0.265N     P=0.223N     |
|POLY 1.5           |     P=0.241N     P=0.523      P=0.500      P=0.344N    |P=0.205N     P=0.297N     P=0.239N     P=0.210N     |
|POLY 6             |     P=0.246N     P=0.542      P=0.497      P=0.342N    |P=0.238N     P=0.300N     P=0.289N     P=0.239N     |
|LOGISTIC REGRESSION|     P=0.251N     P=0.558      P=0.485      P=0.371N    |P=0.191N     P=0.288N     P=0.219N     P=0.171N     |
|COCH-ARM / FISHERS |     P=0.246N     P=0.500      P=0.500      P=0.357N    |P=0.185N     P=0.288N     P=0.194N     P=0.194N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 17
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Infiltration Cellular Histiocyte                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    10/50 (20%)  45/50 (90%)  48/50 (96%) |2/50 (4%)    13/50 (26%)  48/50 (96%)  49/50 (98%)  |
|POLY-3 ADJUSTED (b)|     6.7%         21.6%        94.5%        98.5%       |4.5%         28.3%        99.5%        98.4%        |
|TERMINAL (d)       |     1/35 (3%)    8/38 (21%)   33/34 (97%)  34/34 (100%)|2/36 (6%)    10/34 (29%)  31/31 (100%) 29/29 (100%) |
|FIRST INCIDENCE    |     561          617          393          501         |735 (T)      644          239          365          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   P=0.057      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.002 **   P<0.001 **   P<0.001 **   |
|POLY 3             |     P<0.001 **   P=0.041 *    P<0.001 **   P<0.001 **  |P<0.001 **   P=0.002 **   P<0.001 **   P<0.001 **   |
|POLY 1.5           |     P<0.001 **   P=0.039 *    P<0.001 **   P<0.001 **  |P<0.001 **   P=0.002 **   P<0.001 **   P<0.001 **   |
|POLY 6             |     P<0.001 **   P=0.043 *    P<0.001 **   P<0.001 **  |P<0.001 **   P=0.002 **   P<0.001 **   P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   P=0.040 *    P<0.001 **   P<0.001 **  |P<0.001 **   P=0.003 **   P<0.001 **   P<0.001 **   |
|COCH-ARM / FISHERS |     P<0.001 **   P=0.036 *    P<0.001 **   P<0.001 **  |P<0.001 **   P=0.002 **   P<0.001 **   P<0.001 **   |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Inflammation Chronic Focal                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    3/50 (6%)    3/50 (6%)    12/50 (24%) |1/50 (2%)    2/50 (4%)    11/50 (22%)  18/50 (36%)  |
|POLY-3 ADJUSTED (b)|     2.3%         6.5%         6.7%         26.6%       |2.2%         4.4%         26.2%        42.1%        |
|TERMINAL (d)       |     0/35 (0%)    1/38 (3%)    1/34 (3%)    10/34 (29%) |1/36 (3%)    1/34 (3%)    6/31 (19%)   15/29 (52%)  |
|FIRST INCIDENCE    |     561          617          393          699         |735 (T)      644          609          646          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   P=0.336      P=0.304      P=0.002 **  |P<0.001 **   P=0.497      P=0.002 **   P<0.001 **   |
|POLY 3             |     P<0.001 **   P=0.321      P=0.305      P<0.001 **  |P<0.001 **   P=0.506      P<0.001 **   P<0.001 **   |
|POLY 1.5           |     P<0.001 **   P=0.317      P=0.307      P<0.001 **  |P<0.001 **   P=0.502      P<0.001 **   P<0.001 **   |
|POLY 6             |     P<0.001 **   P=0.327      P=0.302      P<0.001 **  |P<0.001 **   P=0.510      P<0.001 **   P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   P=0.265      P=0.269      P=0.002 **  |P<0.001 **   P=0.500      P=0.002 **   P<0.001 **   |
|COCH-ARM / FISHERS |     P<0.001 **   P=0.309      P=0.309      P<0.001 **  |P<0.001 **   P=0.500      P=0.002 **   P<0.001 **   |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 18
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Inflammation Focal                                                                                                          |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    8/50 (16%)   23/50 (46%) |0/50 (0%)    0/50 (0%)    2/50 (4%)    14/50 (28%)  |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         18.6%        48.9%       |0.0%         0.0%         4.9%         32.9%        |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    8/34 (24%)   19/34 (56%) |0/36 (0%)    0/34 (0%)    2/31 (7%)    12/29 (41%)  |
|FIRST INCIDENCE    |     ---          ---          733 (T)      406         |---          ---          735 (T)      646          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   (e)          P=0.004 **   P<0.001 **  |P<0.001 **   (e)          P=0.206      P<0.001 **   |
|POLY 3             |     P<0.001 **   (e)          P=0.003 **   P<0.001 **  |P<0.001 **   (e)          P=0.216      P<0.001 **   |
|POLY 1.5           |     P<0.001 **   (e)          P=0.003 **   P<0.001 **  |P<0.001 **   (e)          P=0.223      P<0.001 **   |
|POLY 6             |     P<0.001 **   (e)          P=0.003 **   P<0.001 **  |P<0.001 **   (e)          P=0.209      P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   (e)          P=0.004 **   P<0.001 **  |P<0.001 **   (e)          P=0.206      P<0.001 **   |
|COCH-ARM / FISHERS |     P<0.001 **   (e)          P=0.003 **   P<0.001 **  |P<0.001 **   (e)          P=0.247      P<0.001 **   |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung: Alveolar Epithelium                                                                                                        |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     4/50 (8%)    9/50 (18%)   39/50 (78%)  45/50 (90%) |2/50 (4%)    5/50 (10%)   27/50 (54%)  43/50 (86%)  |
|POLY-3 ADJUSTED (b)|     9.1%         19.6%        86.3%        92.5%       |4.5%         11.0%        62.5%        92.2%        |
|TERMINAL (d)       |     3/35 (9%)    9/38 (24%)   33/34 (97%)  33/34 (97%) |2/36 (6%)    5/34 (15%)   20/31 (65%)  27/29 (93%)  |
|FIRST INCIDENCE    |     686          733 (T)      393          501         |735 (T)      735 (T)      365          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   P=0.148      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.192      P<0.001 **   P<0.001 **   |
|POLY 3             |     P<0.001 **   P=0.130      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.220      P<0.001 **   P<0.001 **   |
|POLY 1.5           |     P<0.001 **   P=0.127      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.217      P<0.001 **   P<0.001 **   |
|POLY 6             |     P<0.001 **   P=0.134      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.222      P<0.001 **   P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   P=0.144      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.192      P<0.001 **   P<0.001 **   |
|COCH-ARM / FISHERS |     P<0.001 **   P=0.117      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.218      P<0.001 **   P<0.001 **   |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 19
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung: Alveolus                                                                                                                   |
|     Foreign Body                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    4/50 (8%)    46/50 (92%)  50/50 (100%)|0/50 (0%)    8/50 (16%)   48/50 (96%)  49/50 (98%)  |
|POLY-3 ADJUSTED (b)|     0.0%         8.7%         95.6%        100.0%      |0.0%         17.7%        99.5%        98.4%        |
|TERMINAL (d)       |     0/35 (0%)    4/38 (11%)   33/34 (97%)  34/34 (100%)|0/36 (0%)    8/34 (24%)   31/31 (100%) 29/29 (100%) |
|FIRST INCIDENCE    |     ---          733 (T)      393          406         |---          735 (T)      239          365          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   P=0.074      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.003 **   P<0.001 **   P<0.001 **   |
|POLY 3             |     P<0.001 **   P=0.066      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.004 **   P<0.001 **   P<0.001 **   |
|POLY 1.5           |     P<0.001 **   P=0.065      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.004 **   P<0.001 **   P<0.001 **   |
|POLY 6             |     P<0.001 **   P=0.068      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.004 **   P<0.001 **   P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   P=0.074      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.003 **   P<0.001 **   P<0.001 **   |
|COCH-ARM / FISHERS |     P<0.001 **   P=0.059      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.003 **   P<0.001 **   P<0.001 **   |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung: Alveolus                                                                                                                   |
|     Proteinosis                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    4/50 (8%)    49/50 (98%)  50/50 (100%)|0/50 (0%)    4/50 (8%)    49/50 (98%)  50/50 (100%) |
|POLY-3 ADJUSTED (b)|     2.3%         8.7%         99.9%        100.0%      |0.0%         8.8%         99.9%        100.0%       |
|TERMINAL (d)       |     0/35 (0%)    3/38 (8%)    34/34 (100%) 34/34 (100%)|0/36 (0%)    4/34 (12%)   31/31 (100%) 29/29 (100%) |
|FIRST INCIDENCE    |     561          710          393          406         |---          735 (T)      281          365          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   P=0.208      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.056      P<0.001 **   P<0.001 **   |
|POLY 3             |     P<0.001 **   P=0.189      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.061      P<0.001 **   P<0.001 **   |
|POLY 1.5           |     P<0.001 **   P=0.187      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.061      P<0.001 **   P<0.001 **   |
|POLY 6             |     P<0.001 **   P=0.192      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.062      P<0.001 **   P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   P=0.176      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.056      P<0.001 **   P<0.001 **   |
|COCH-ARM / FISHERS |     P<0.001 **   P=0.181      P<0.001 **   P<0.001 **  |P<0.001 **   P=0.059      P<0.001 **   P<0.001 **   |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 20
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung: Perivascular                                                                                                               |
|     Infiltration Cellular Mononuclear Cell                                                                                      |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)   |2/50 (4%)    0/50 (0%)    2/50 (4%)    2/50 (4%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |4.5%         0.0%         4.9%         4.8%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |2/36 (6%)    0/34 (0%)    2/31 (7%)    2/29 (7%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |735 (T)      ---          735 (T)      735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.281      P=0.251N     P=0.641      P=0.615      |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.324      P=0.235N     P=0.658      P=0.671      |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.339      P=0.237N     P=0.670      P=0.681      |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.310      P=0.233N     P=0.647      P=0.660      |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.281      (e)          P=0.641      P=0.615      |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.356      P=0.247N     P=0.691N     P=0.691N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lymph Node                                                                                                                       |
|     Angiectasis                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/2 (0%)     0/0 (0%)     0/2 (0%)     0/1 (0%)    |2/4 (50%)    1/8 (13%)    2/5 (40%)    0/6 (0%)     |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |65.8%        14.4%        56.3%        0.0%         |
|TERMINAL (d)       |     0/1 (0%)     0/0 (0%)     0/2 (0%)     0/0 (0%)    |2/2 (100%)   1/5 (20%)    2/3 (67%)    0/3 (0%)     |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |735 (T)      735 (T)      735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.204N     P=0.157N     P=0.581N     P=0.122N     |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.160N     P=0.183N     P=0.706N     P=0.057N     |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.170N     P=0.208N     P=0.694N     P=0.074N     |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.151N     P=0.151N     P=0.687N     P=0.038N*    |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.204N     P=0.157N     P=0.581N     (e)          |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.194N     P=0.236N     P=0.643N     P=0.133N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 21
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lymph Node, Bronchial                                                                                                            |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     5/38 (13%)   7/37 (19%)   17/40 (43%)  24/41 (59%) |10/39 (26%)  12/43 (28%)  13/42 (31%)  23/42 (55%)  |
|POLY-3 ADJUSTED (b)|     14.5%        20.3%        46.7%        60.9%       |27.2%        29.9%        36.1%        61.9%        |
|TERMINAL (d)       |     4/28 (14%)   6/28 (21%)   15/31 (48%)  22/32 (69%) |8/29 (28%)   10/31 (32%)  12/28 (43%)  19/26 (73%)  |
|FIRST INCIDENCE    |     702          617          672          591         |533          659          711          628          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P<0.001 **   P=0.388      P=0.006 **   P<0.001 **  |P<0.001 **   P=0.472      P=0.265      P<0.001 **   |
|POLY 3             |     P<0.001 **   P=0.374      P=0.002 **   P<0.001 **  |P<0.001 **   P=0.499      P=0.288      P=0.002 **   |
|POLY 1.5           |     P<0.001 **   P=0.367      P=0.002 **   P<0.001 **  |P<0.001 **   P=0.500      P=0.327      P=0.003 **   |
|POLY 6             |     P<0.001 **   P=0.385      P=0.002 **   P<0.001 **  |P<0.001 **   P=0.500      P=0.245      P<0.001 **   |
|LOGISTIC REGRESSION|     P<0.001 **   P=0.370      P=0.004 **   P<0.001 **  |P<0.001 **   P=0.508      P=0.290      P=0.003 **   |
|COCH-ARM / FISHERS |     P<0.001 **   P=0.358      P=0.004 **   P<0.001 **  |P=0.002 **   P=0.508      P=0.389      P=0.007 **   |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lymph Node, Mandibular                                                                                                           |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/37 (5%)    3/40 (8%)    0/28 (0%)    0/32 (0%)   |1/35 (3%)    0/37 (0%)    1/43 (2%)    2/43 (5%)    |
|POLY-3 ADJUSTED (b)|     6.3%         8.2%         0.0%         0.0%        |3.3%         0.0%         2.9%         5.5%         |
|TERMINAL (d)       |     1/26 (4%)    3/30 (10%)   0/18 (0%)    0/23 (0%)   |1/25 (4%)    0/25 (0%)    1/27 (4%)    2/25 (8%)    |
|FIRST INCIDENCE    |     686          733 (T)      ---          ---         |735 (T)      ---          735 (T)      735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.071N     P=0.556      P=0.292N     P=0.256N    |P=0.202      P=0.500N     P=0.745N     P=0.500      |
|POLY 3             |     P=0.067N     P=0.563      P=0.307N     P=0.251N    |P=0.235      P=0.484N     P=0.732N     P=0.559      |
|POLY 1.5           |     P=0.067N     P=0.556      P=0.304N     P=0.255N    |P=0.244      P=0.487N     P=0.726N     P=0.565      |
|POLY 6             |     P=0.067N     P=0.571      P=0.309N     P=0.248N    |P=0.226      P=0.481N     P=0.737N     P=0.552      |
|LOGISTIC REGRESSION|     P=0.067N     P=0.575      P=0.304N     P=0.255N    |P=0.202      (e)          P=0.745N     P=0.500      |
|COCH-ARM / FISHERS |     P=0.070N     P=0.537      P=0.320N     P=0.284N    |P=0.251      P=0.486N     P=0.699N     P=0.578      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 22
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lymph Node, Mediastinal                                                                                                          |
|     Hematopoietic Cell Proliferation                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/38 (0%)    1/36 (3%)    0/38 (0%)    0/33 (0%)   |0/40 (0%)    0/43 (0%)    2/49 (4%)    0/45 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.9%         0.0%         0.0%        |0.0%         0.0%         5.0%         0.0%         |
|TERMINAL (d)       |     0/29 (0%)    1/31 (3%)    0/28 (0%)    0/25 (0%)   |0/29 (0%)    0/31 (0%)    1/30 (3%)    0/27 (0%)    |
|FIRST INCIDENCE    |     ---          733 (T)      ---          ---         |---          ---          421          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.477N     P=0.513      (e)          (e)         |P=0.525      (e)          P=0.239      (e)          |
|POLY 3             |     P=0.462N     P=0.498      (e)          (e)         |P=0.516      (e)          P=0.258      (e)          |
|POLY 1.5           |     P=0.464N     P=0.495      (e)          (e)         |P=0.532      (e)          P=0.265      (e)          |
|POLY 6             |     P=0.460N     P=0.502      (e)          (e)         |P=0.503      (e)          P=0.253      (e)          |
|LOGISTIC REGRESSION|     (e)          P=0.513      (e)          (e)         |P=0.676      (e)          P=0.395      (e)          |
|COCH-ARM / FISHERS |     P=0.465N     P=0.486      (e)          (e)         |P=0.561      (e)          P=0.300      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lymph Node, Mediastinal                                                                                                          |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/38 (3%)    1/36 (3%)    4/38 (11%)   3/33 (9%)   |5/40 (13%)   3/43 (7%)    6/49 (12%)   8/45 (18%)   |
|POLY-3 ADJUSTED (b)|     2.9%         2.9%         11.5%        9.4%        |13.3%        7.4%         15.1%        20.9%        |
|TERMINAL (d)       |     1/29 (3%)    1/31 (3%)    2/28 (7%)    0/25 (0%)   |2/29 (7%)    2/31 (7%)    5/30 (17%)   7/27 (26%)   |
|FIRST INCIDENCE    |     733 (T)      733 (T)      645          501         |533          715          659          646          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.119      P=0.747N     P=0.168      P=0.301     |P=0.065      P=0.344N     P=0.480      P=0.228      |
|POLY 3             |     P=0.117      P=0.758      P=0.176      P=0.274     |P=0.089      P=0.316N     P=0.541      P=0.283      |
|POLY 1.5           |     P=0.113      P=0.754      P=0.175      P=0.267     |P=0.104      P=0.316N     P=0.572      P=0.308      |
|POLY 6             |     P=0.121      P=0.758N     P=0.179      P=0.281     |P=0.078      P=0.317N     P=0.516      P=0.261      |
|LOGISTIC REGRESSION|     P=0.101      P=0.747N     P=0.176      P=0.197     |P=0.096      P=0.350N     P=0.591      P=0.320      |
|COCH-ARM / FISHERS |     P=0.106      P=0.740      P=0.179      P=0.255     |P=0.136      P=0.316N     P=0.609N     P=0.357      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 23
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lymph Node, Mesenteric                                                                                                           |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/48 (6%)    5/49 (10%)   4/50 (8%)    4/46 (9%)   |3/49 (6%)    3/49 (6%)    5/50 (10%)   6/47 (13%)   |
|POLY-3 ADJUSTED (b)|     6.9%         10.9%        9.3%         9.4%        |6.7%         6.7%         12.1%        14.5%        |
|TERMINAL (d)       |     2/35 (6%)    2/38 (5%)    3/34 (9%)    3/33 (9%)   |3/36 (8%)    2/34 (6%)    3/31 (10%)   2/28 (7%)    |
|FIRST INCIDENCE    |     686          609          729          723         |735 (T)      659          645          365          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.494      P=0.406      P=0.481      P=0.478     |P=0.080      P=0.647      P=0.280      P=0.180      |
|POLY 3             |     P=0.509      P=0.381      P=0.489      P=0.485     |P=0.098      P=0.661      P=0.311      P=0.205      |
|POLY 1.5           |     P=0.510      P=0.375      P=0.500      P=0.482     |P=0.106      P=0.657      P=0.326      P=0.211      |
|POLY 6             |     P=0.504      P=0.392      P=0.478      P=0.487     |P=0.092      P=0.659N     P=0.301      P=0.199      |
|LOGISTIC REGRESSION|     P=0.512      P=0.367      P=0.478      P=0.490     |P=0.126      P=0.660      P=0.306      P=0.328      |
|COCH-ARM / FISHERS |     P=0.511      P=0.369      P=0.523      P=0.476     |P=0.115      P=0.661N     P=0.369      P=0.223      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/0 (0%)     0/0 (0%)     0/0 (0%)     0/0 (0%)    |4/50 (8%)    4/50 (8%)    2/50 (4%)    3/49 (6%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |8.9%         8.8%         4.9%         7.3%         |
|TERMINAL (d)       |     0/0 (0%)     0/0 (0%)     0/0 (0%)     0/0 (0%)    |4/36 (11%)   3/34 (9%)    2/31 (7%)    2/29 (7%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |735 (T)      701          735 (T)      717          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.453N     P=0.619      P=0.407N     P=0.613N     |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.399N     P=0.636N     P=0.384N     P=0.546N     |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.380N     P=0.641N     P=0.368N     P=0.531N     |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.418N     P=0.631N     P=0.398N     P=0.563N     |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.443N     P=0.641N     P=0.407N     P=0.595N     |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.354N     P=0.643N     P=0.339N     P=0.511N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 24
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mesentery                                                                                                                        |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/4 (0%)     0/5 (0%)     0/4 (0%)     0/6 (0%)    |0/8 (0%)     0/9 (0%)     2/16 (13%)   0/13 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |0.0%         0.0%         15.6%        0.0%         |
|TERMINAL (d)       |     0/3 (0%)     0/4 (0%)     0/3 (0%)     0/5 (0%)    |0/4 (0%)     0/4 (0%)     0/6 (0%)     0/7 (0%)     |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |---          ---          421          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.511      (e)          P=0.221      (e)          |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.584      (e)          P=0.376      (e)          |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.610      (e)          P=0.383      (e)          |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.559      (e)          P=0.367      (e)          |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.665N     (e)          P=0.498      (e)          |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.650      (e)          P=0.435      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mesentery: Fat                                                                                                                   |
|     Necrosis                                                                                                                    |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/4 (25%)    5/5 (100%)   3/4 (75%)    6/6 (100%)  |4/8 (50%)    9/9 (100%)   13/16 (81%)  11/13 (85%)  |
|POLY-3 ADJUSTED (b)|     28.8%        100.0%       75.3%        100.0%      |55.2%        100.0%       92.1%        94.8%        |
|TERMINAL (d)       |     1/3 (33%)    4/4 (100%)   3/3 (100%)   5/5 (100%)  |3/4 (75%)    4/4 (100%)   6/6 (100%)   7/7 (100%)   |
|FIRST INCIDENCE    |     733 (T)      715          733 (T)      665         |645          533          421          505          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.111      P=0.086      P=0.215      P=0.064     |P=0.134      P=0.067      P=0.013 *    P=0.077      |
|POLY 3             |     P=0.084      P=0.019 *    P=0.299      P=0.009 **  |P=0.086      P=0.027 *    P=0.045 *    P=0.038 *    |
|POLY 1.5           |     P=0.057      P=0.012 *    P=0.272      P=0.005 **  |P=0.155      P=0.020 *    P=0.064      P=0.057      |
|POLY 6             |     P=0.131      P=0.037 *    P=0.335      P=0.021 *   |P=0.046 *    P=0.041 *    P=0.033 *    P=0.030 *    |
|LOGISTIC REGRESSION|     P=0.103      P=0.088      P=0.215      P=0.048 *   |P=0.115      P=0.033 *    P=0.051      P=0.038 *    |
|COCH-ARM / FISHERS |     P=0.079      P=0.048 *    P=0.243      P=0.033 *   |P=0.301      P=0.029 *    P=0.134      P=0.115      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 25
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Nose                                                                                                                             |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/49 (0%)    3/49 (6%)    2/49 (4%)    1/48 (2%)   |2/50 (4%)    0/49 (0%)    4/50 (8%)    4/50 (8%)    |
|POLY-3 ADJUSTED (b)|     0.0%         6.6%         4.7%         2.3%        |4.4%         0.0%         9.3%         9.3%         |
|TERMINAL (d)       |     0/34 (0%)    3/38 (8%)    1/34 (3%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    1/31 (3%)    3/29 (10%)   |
|FIRST INCIDENCE    |     ---          733 (T)      608          699         |694          ---          239          490          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.580N     P=0.141      P=0.242      P=0.500     |P=0.057      P=0.234N     P=0.300      P=0.276      |
|POLY 3             |     P=0.548N     P=0.128      P=0.235      P=0.507     |P=0.061      P=0.237N     P=0.313      P=0.313      |
|POLY 1.5           |     P=0.553N     P=0.126      P=0.237      P=0.504     |P=0.067      P=0.239N     P=0.322      P=0.324      |
|POLY 6             |     P=0.543N     P=0.132      P=0.234      P=0.509     |P=0.055      P=0.236N     P=0.305      P=0.300      |
|LOGISTIC REGRESSION|     P=0.565N     P=0.141      P=0.237      P=0.497     |P=0.091      P=0.242N     P=0.473      P=0.343      |
|COCH-ARM / FISHERS |     P=0.571N     P=0.121      P=0.247      P=0.495     |P=0.077      P=0.253N     P=0.339      P=0.339      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Nose: Olfactory Epithelium                                                                                                       |
|     Atrophy                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     7/49 (14%)   2/49 (4%)    5/49 (10%)   8/48 (17%)  |3/50 (6%)    1/49 (2%)    7/50 (14%)   4/50 (8%)    |
|POLY-3 ADJUSTED (b)|     16.3%        4.4%         11.9%        18.0%       |6.7%         2.2%         16.9%        9.2%         |
|TERMINAL (d)       |     7/34 (21%)   2/38 (5%)    5/34 (15%)   6/34 (18%)  |3/36 (8%)    1/34 (3%)    5/31 (16%)   2/29 (7%)    |
|FIRST INCIDENCE    |     733 (T)      733 (T)      733 (T)      699         |735 (T)      735 (T)      553          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.143      P=0.055N     P=0.376N     P=0.502     |P=0.115      P=0.325N     P=0.110      P=0.409      |
|POLY 3             |     P=0.162      P=0.066N     P=0.391N     P=0.530     |P=0.151      P=0.302N     P=0.127      P=0.480      |
|POLY 1.5           |     P=0.163      P=0.070N     P=0.384N     P=0.518     |P=0.164      P=0.307N     P=0.136      P=0.489      |
|POLY 6             |     P=0.159      P=0.062N     P=0.398N     P=0.540     |P=0.140      P=0.299N     P=0.121      P=0.471      |
|LOGISTIC REGRESSION|     P=0.161      P=0.055N     P=0.376N     P=0.536     |P=0.179      P=0.325N     P=0.130      P=0.510      |
|COCH-ARM / FISHERS |     P=0.161      P=0.080N     P=0.380N     P=0.482     |P=0.183      P=0.316N     P=0.159      P=0.500      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 26
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Nose: Olfactory Epithelium                                                                                                       |
|     Degeneration Hyaline                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/49 (2%)    4/49 (8%)    6/49 (12%)   1/48 (2%)   |3/50 (6%)    1/49 (2%)    10/50 (20%)  5/50 (10%)   |
|POLY-3 ADJUSTED (b)|     2.3%         8.9%         14.2%        2.3%        |6.7%         2.2%         23.6%        11.9%        |
|TERMINAL (d)       |     1/34 (3%)    4/38 (11%)   5/34 (15%)   1/34 (3%)   |3/36 (8%)    1/34 (3%)    6/31 (19%)   4/29 (14%)   |
|FIRST INCIDENCE    |     733 (T)      733 (T)      715          733 (T)     |735 (T)      735 (T)      239          714          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.484N     P=0.214      P=0.059      P=0.762     |P=0.044 *    P=0.325N     P=0.023 *    P=0.249      |
|POLY 3             |     P=0.434N     P=0.195      P=0.052      P=0.754N    |P=0.054      P=0.302N     P=0.025 *    P=0.323      |
|POLY 1.5           |     P=0.441N     P=0.190      P=0.054      P=0.756N    |P=0.065      P=0.307N     P=0.028 *    P=0.337      |
|POLY 6             |     P=0.431N     P=0.201      P=0.051      P=0.752N    |P=0.045 *    P=0.299N     P=0.023 *    P=0.307      |
|LOGISTIC REGRESSION|     P=0.464N     P=0.214      P=0.051      P=0.762     |P=0.080      P=0.325N     P=0.036 *    P=0.275      |
|COCH-ARM / FISHERS |     P=0.466N     P=0.181      P=0.056      P=0.747     |P=0.087      P=0.316N     P=0.036 *    P=0.357      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Nose: Respiratory Epithelium                                                                                                     |
|     Degeneration Hyaline                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/49 (2%)    2/49 (4%)    2/49 (4%)    1/48 (2%)   |15/50 (30%)  17/49 (35%)  21/50 (42%)  17/50 (34%)  |
|POLY-3 ADJUSTED (b)|     2.3%         4.4%         4.8%         2.3%        |32.9%        37.0%        48.6%        38.4%        |
|TERMINAL (d)       |     1/34 (3%)    2/38 (5%)    2/34 (6%)    1/34 (3%)   |14/36 (39%)  14/34 (41%)  15/31 (48%)  13/29 (45%)  |
|FIRST INCIDENCE    |     733 (T)      733 (T)      733 (T)      733 (T)     |439          533          239          490          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.543N     P=0.539      P=0.500      P=0.762     |P=0.132      P=0.349      P=0.061      P=0.187      |
|POLY 3             |     P=0.516N     P=0.518      P=0.494      P=0.754N    |P=0.287      P=0.425      P=0.094      P=0.371      |
|POLY 1.5           |     P=0.518N     P=0.513      P=0.497      P=0.756N    |P=0.324      P=0.407      P=0.109      P=0.390      |
|POLY 6             |     P=0.516N     P=0.525      P=0.490      P=0.752N    |P=0.253      P=0.441      P=0.087      P=0.350      |
|LOGISTIC REGRESSION|     P=0.543N     P=0.539      P=0.500      P=0.762     |P=0.314      P=0.416      P=0.107      P=0.379      |
|COCH-ARM / FISHERS |     P=0.529N     P=0.500      P=0.500      P=0.747     |P=0.375      P=0.388      P=0.149      P=0.415      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 27
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Nose: Respiratory Epithelium                                                                                                     |
|     Metaplasia                                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/49 (0%)    0/49 (0%)    0/49 (0%)    0/48 (0%)   |0/50 (0%)    0/49 (0%)    2/50 (4%)    2/50 (4%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |0.0%         0.0%         4.8%         4.7%         |
|TERMINAL (d)       |     0/34 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    1/31 (3%)    1/29 (3%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |---          ---          239          682          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.057      (e)          P=0.225      P=0.205      |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.060      (e)          P=0.220      P=0.224      |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.065      (e)          P=0.227      P=0.230      |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.056      (e)          P=0.215      P=0.219      |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.077      (e)          P=0.332      P=0.227      |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.071      (e)          P=0.247      P=0.247      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Ovary                                                                                                                            |
|     Angiectasis                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |2/49 (4%)    0/50 (0%)    2/50 (4%)    0/46 (0%)    |
|POLY-3 ADJUSTED (b)|                                                        |4.5%         0.0%         4.9%         0.0%         |
|TERMINAL (d)       |                                                        |2/36 (6%)    0/34 (0%)    2/31 (7%)    0/28 (0%)    |
|FIRST INCIDENCE    |                                                        |735 (T)      ---          735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.394N     P=0.251N     P=0.641      P=0.295N     |
|POLY 3             |                                                        |P=0.373N     P=0.235N     P=0.658      P=0.272N     |
|POLY 1.5           |                                                        |P=0.360N     P=0.236N     P=0.671      P=0.265N     |
|POLY 6             |                                                        |P=0.385N     P=0.233N     P=0.647      P=0.280N     |
|LOGISTIC REGRESSION|                                                        |P=0.394N     (e)          P=0.641      (e)          |
|COCH-ARM / FISHERS |                                                        |P=0.344N     P=0.242N     P=0.684N     P=0.263N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 28
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Ovary                                                                                                                            |
|     Atrophy                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |3/49 (6%)    2/50 (4%)    2/50 (4%)    0/46 (0%)    |
|POLY-3 ADJUSTED (b)|                                                        |6.7%         4.4%         4.9%         0.0%         |
|TERMINAL (d)       |                                                        |2/36 (6%)    0/34 (0%)    2/31 (7%)    0/28 (0%)    |
|FIRST INCIDENCE    |                                                        |729          715          735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.137N     P=0.523N     P=0.570N     P=0.170N     |
|POLY 3             |                                                        |P=0.123N     P=0.494N     P=0.545N     P=0.148N     |
|POLY 1.5           |                                                        |P=0.115N     P=0.497N     P=0.529N     P=0.141N     |
|POLY 6             |                                                        |P=0.132N     P=0.491N     P=0.559N     P=0.155N     |
|LOGISTIC REGRESSION|                                                        |P=0.134N     P=0.494N     P=0.570N     P=0.162N     |
|COCH-ARM / FISHERS |                                                        |P=0.102N     P=0.490N     P=0.490N     P=0.133N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Ovary                                                                                                                            |
|     Cyst                                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |18/49 (37%)  17/50 (34%)  23/50 (46%)  15/46 (33%)  |
|POLY-3 ADJUSTED (b)|                                                        |38.9%        36.2%        51.2%        36.3%        |
|TERMINAL (d)       |                                                        |15/36 (42%)  11/34 (32%)  13/31 (42%)  7/28 (25%)   |
|FIRST INCIDENCE    |                                                        |439          302          239          464          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.379      P=0.546N     P=0.107      P=0.561      |
|POLY 3             |                                                        |P=0.480      P=0.477N     P=0.164      P=0.486N     |
|POLY 1.5           |                                                        |P=0.514      P=0.484N     P=0.178      P=0.466N     |
|POLY 6             |                                                        |P=0.460      P=0.466N     P=0.164      P=0.497N     |
|LOGISTIC REGRESSION|                                                        |P=0.487N     P=0.469N     P=0.233      P=0.397N     |
|COCH-ARM / FISHERS |                                                        |P=0.500N     P=0.470N     P=0.232      P=0.419N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 29
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Pancreas                                                                                                                         |
|     Atrophy                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     13/50 (26%)  7/50 (14%)   9/49 (18%)   6/47 (13%)  |5/50 (10%)   10/50 (20%)  11/50 (22%)  2/49 (4%)    |
|POLY-3 ADJUSTED (b)|     28.2%        15.0%        20.6%        13.8%       |11.1%        21.9%        26.4%        4.8%         |
|TERMINAL (d)       |     8/35 (23%)   4/38 (11%)   6/34 (18%)   5/34 (15%)  |4/36 (11%)   9/34 (27%)   8/31 (26%)   1/29 (3%)    |
|FIRST INCIDENCE    |     457          473          608          645         |707          659          365          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.150N     P=0.087N     P=0.270N     P=0.075N    |P=0.194N     P=0.113      P=0.051      P=0.295N     |
|POLY 3             |     P=0.147N     P=0.096N     P=0.277N     P=0.076N    |P=0.135N     P=0.134      P=0.058      P=0.244N     |
|POLY 1.5           |     P=0.144N     P=0.096N     P=0.265N     P=0.075N    |P=0.121N     P=0.131      P=0.067      P=0.236N     |
|POLY 6             |     P=0.153N     P=0.095N     P=0.288N     P=0.079N    |P=0.152N     P=0.137      P=0.052      P=0.254N     |
|LOGISTIC REGRESSION|     P=0.150N     P=0.119N     P=0.251N     P=0.088N    |P=0.130N     P=0.136      P=0.063      P=0.229N     |
|COCH-ARM / FISHERS |     P=0.146N     P=0.105N     P=0.251N     P=0.082N    |P=0.110N     P=0.131      P=0.086      P=0.226N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Pancreas                                                                                                                         |
|     Cytoplasmic Alteration                                                                                                      |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/49 (0%)    0/47 (0%)   |1/50 (2%)    1/50 (2%)    2/50 (4%)    1/49 (2%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |2.2%         2.2%         4.9%         2.4%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    1/31 (3%)    1/29 (3%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |553          715          609          735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.510      P=0.757N     P=0.462      P=0.726      |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.525      P=0.760      P=0.465      P=0.739      |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.541      P=0.759      P=0.476      P=0.746      |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.508      P=0.760N     P=0.455      P=0.731      |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.572      P=0.755N     P=0.546      P=0.755N     |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.562      P=0.753N     P=0.500      P=0.747      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 30
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Pancreas: Duct                                                                                                                   |
|     Cyst                                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/49 (0%)    0/47 (0%)   |0/50 (0%)    2/50 (4%)    2/50 (4%)    0/49 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |0.0%         4.4%         4.9%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    2/34 (6%)    1/31 (3%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |---          735 (T)      659          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.483N     P=0.226      P=0.207      (e)          |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.457N     P=0.239      P=0.217      (e)          |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.446N     P=0.238      P=0.223      (e)          |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.470N     P=0.241      P=0.212      (e)          |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.455N     P=0.226      P=0.226      (e)          |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.430N     P=0.247      P=0.247      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis                                                                                                   |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/48 (0%)    1/48 (2%)    1/47 (2%)    1/47 (2%)   |16/46 (35%)  20/48 (42%)  20/50 (40%)  9/47 (19%)   |
|POLY-3 ADJUSTED (b)|     0.0%         2.3%         2.5%         2.3%        |37.5%        45.3%        46.6%        22.5%        |
|TERMINAL (d)       |     0/34 (0%)    1/36 (3%)    1/33 (3%)    1/34 (3%)   |12/33 (36%)  15/34 (44%)  13/31 (42%)  8/29 (28%)   |
|FIRST INCIDENCE    |     ---          733 (T)      733 (T)      733 (T)     |645          659          553          505          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.404      P=0.511      P=0.494      P=0.500     |P=0.109N     P=0.312      P=0.192      P=0.150N     |
|POLY 3             |     P=0.419      P=0.505      P=0.490      P=0.503     |P=0.055N     P=0.301      P=0.260      P=0.105N     |
|POLY 1.5           |     P=0.414      P=0.503      P=0.491      P=0.500     |P=0.040N*    P=0.295      P=0.287      P=0.090N     |
|POLY 6             |     P=0.423      P=0.507      P=0.488      P=0.506     |P=0.076N     P=0.309      P=0.246      P=0.126N     |
|LOGISTIC REGRESSION|     (e)          P=0.511      P=0.494      P=0.500     |P=0.055N     P=0.316      P=0.251      P=0.108N     |
|COCH-ARM / FISHERS |     P=0.406      P=0.500      P=0.495      P=0.495     |P=0.028N*    P=0.318      P=0.376      P=0.071N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 31
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Preputial Gland                                                                                                                  |
|     Ectasia                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     5/50 (10%)   3/49 (6%)    5/49 (10%)   5/48 (10%)  |                                                    |
|POLY-3 ADJUSTED (b)|     11.4%        6.7%         11.7%        11.2%       |                                                    |
|TERMINAL (d)       |     5/35 (14%)   2/37 (5%)    4/34 (12%)   3/34 (9%)   |                                                    |
|FIRST INCIDENCE    |     733 (T)      715          645          659         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.381      P=0.322N     P=0.611      P=0.618     |                                                    |
|POLY 3             |     P=0.411      P=0.343N     P=0.615      P=0.621N    |                                                    |
|POLY 1.5           |     P=0.406      P=0.349N     P=0.617      P=0.629N    |                                                    |
|POLY 6             |     P=0.413      P=0.334N     P=0.614      P=0.613N    |                                                    |
|LOGISTIC REGRESSION|     P=0.407      P=0.324N     P=0.605      P=0.621N    |                                                    |
|COCH-ARM / FISHERS |     P=0.390      P=0.369N     P=0.617      P=0.603     |                                                    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Preputial Gland                                                                                                                  |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    3/49 (6%)    4/49 (8%)    9/48 (19%)  |                                                    |
|POLY-3 ADJUSTED (b)|     6.8%         6.6%         9.2%         19.7%       |                                                    |
|TERMINAL (d)       |     3/35 (9%)    2/37 (5%)    1/34 (3%)    3/34 (9%)   |                                                    |
|FIRST INCIDENCE    |     733 (T)      617          609          555         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.018 *    P=0.635N     P=0.481      P=0.070     |                                                    |
|POLY 3             |     P=0.017 *    P=0.648N     P=0.494      P=0.069     |                                                    |
|POLY 1.5           |     P=0.016 *    P=0.654N     P=0.493      P=0.063     |                                                    |
|POLY 6             |     P=0.019 *    P=0.639N     P=0.498      P=0.076     |                                                    |
|LOGISTIC REGRESSION|     P=0.014 *    P=0.657N     P=0.488      P=0.051     |                                                    |
|COCH-ARM / FISHERS |     P=0.015 *    P=0.651      P=0.489      P=0.052     |                                                    |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 32
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Prostate                                                                                                                         |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/49 (0%)    1/49 (2%)    1/49 (2%)   |                                                    |
|POLY-3 ADJUSTED (b)|     4.4%         0.0%         2.4%         2.2%        |                                                    |
|TERMINAL (d)       |     0/35 (0%)    0/37 (0%)    1/33 (3%)    0/34 (0%)   |                                                    |
|FIRST INCIDENCE    |     462          ---          733 (T)      555         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.580N     P=0.235N     P=0.512N     P=0.495N    |                                                    |
|POLY 3             |     P=0.585N     P=0.239N     P=0.526N     P=0.501N    |                                                    |
|POLY 1.5           |     P=0.583N     P=0.239N     P=0.517N     P=0.501N    |                                                    |
|POLY 6             |     P=0.587N     P=0.238N     P=0.535N     P=0.502N    |                                                    |
|LOGISTIC REGRESSION|     P=0.616      P=0.345N     P=0.524N     P=0.665N    |                                                    |
|COCH-ARM / FISHERS |     P=0.580N     P=0.253N     P=0.508N     P=0.508N    |                                                    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin: Prepuce                                                                                                                    |
|     Inflammation Chronic                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    4/50 (8%)    3/50 (6%)    3/50 (6%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     4.5%         8.6%         6.8%         6.6%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     1/35 (3%)    2/38 (5%)    1/34 (3%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     561          617          548          555         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.527      P=0.373      P=0.487      P=0.499     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.553      P=0.356      P=0.494      P=0.513     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.553      P=0.352      P=0.498      P=0.511     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.551      P=0.363      P=0.491      P=0.514     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.531      P=0.322      P=0.496      P=0.464     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.545      P=0.339      P=0.500      P=0.500     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 33
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin: Subcutaneous Tissue                                                                                                        |
|     Hemorrhage                                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)   |0/50 (0%)    2/50 (4%)    2/50 (4%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |0.0%         4.2%         4.8%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |---          124          483          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.434N     P=0.240      P=0.220      (e)          |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.453N     P=0.249      P=0.221      (e)          |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.440N     P=0.246      P=0.226      (e)          |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.466N     P=0.251      P=0.218      (e)          |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.467N     P=0.304      P=0.302      (e)          |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.424N     P=0.247      P=0.247      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin: Subcutaneous Tissue                                                                                                        |
|     Inflammation Chronic                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    2/50 (4%)    0/50 (0%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         4.7%         0.0%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    2/34 (6%)    0/34 (0%)   |0/36 (0%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          ---          733 (T)      ---         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.520      (e)          P=0.232      (e)         |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.544      (e)          P=0.232      (e)         |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.544      (e)          P=0.235      (e)         |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.542      (e)          P=0.229      (e)         |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     (e)          (e)          P=0.232      (e)         |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.536      (e)          P=0.247      (e)         |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 34
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Spleen                                                                                                                           |
|     Hematopoietic Cell Proliferation                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     17/50 (34%)  13/50 (26%)  19/49 (39%)  18/47 (38%) |23/50 (46%)  22/50 (44%)  22/50 (44%)  28/49 (57%)  |
|POLY-3 ADJUSTED (b)|     36.6%        27.2%        41.9%        39.3%       |48.7%        46.5%        48.2%        62.4%        |
|TERMINAL (d)       |     8/35 (23%)   8/38 (21%)   11/34 (32%)  8/34 (24%)  |15/36 (42%)  14/34 (41%)  11/31 (36%)  16/29 (55%)  |
|FIRST INCIDENCE    |     561          478          232          555         |533          533          281          412          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.231      P=0.213N     P=0.383      P=0.498     |P=0.048 *    P=0.538N     P=0.432      P=0.081      |
|POLY 3             |     P=0.208      P=0.224N     P=0.380      P=0.479     |P=0.077      P=0.496N     P=0.564N     P=0.129      |
|POLY 1.5           |     P=0.200      P=0.227N     P=0.394      P=0.465     |P=0.096      P=0.505N     P=0.539N     P=0.151      |
|POLY 6             |     P=0.215      P=0.228N     P=0.363      P=0.488     |P=0.059      P=0.490N     P=0.575      P=0.107      |
|LOGISTIC REGRESSION|     P=0.158      P=0.280N     P=0.388      P=0.380     |P=0.113      P=0.500N     P=0.481N     P=0.159      |
|COCH-ARM / FISHERS |     P=0.177      P=0.257N     P=0.388      P=0.409     |P=0.121      P=0.500N     P=0.500N     P=0.182      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Spleen                                                                                                                           |
|     Hyperplasia Lymphoid                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    5/50 (10%)   3/49 (6%)    2/47 (4%)   |20/50 (40%)  12/50 (24%)  18/50 (36%)  7/49 (14%)   |
|POLY-3 ADJUSTED (b)|     2.3%         10.9%        7.1%         4.6%        |43.6%        26.3%        43.0%        17.0%        |
|TERMINAL (d)       |     1/35 (3%)    4/38 (11%)   3/34 (9%)    1/34 (3%)   |17/36 (47%)  10/34 (29%)  14/31 (45%)  7/29 (24%)   |
|FIRST INCIDENCE    |     733 (T)      715          733 (T)      723         |553          659          623          735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.488N     P=0.127      P=0.294      P=0.496     |P=0.067N     P=0.087N     P=0.517      P=0.015N*    |
|POLY 3             |     P=0.463N     P=0.112      P=0.294      P=0.496     |P=0.034N*    P=0.061N     P=0.561N     P=0.005N**   |
|POLY 1.5           |     P=0.468N     P=0.110      P=0.297      P=0.492     |P=0.025N*    P=0.064N     P=0.516N     P=0.004N**   |
|POLY 6             |     P=0.460N     P=0.116      P=0.291      P=0.499     |P=0.047N*    P=0.060N     P=0.583      P=0.007N**   |
|LOGISTIC REGRESSION|     P=0.478N     P=0.120      P=0.294      P=0.500     |P=0.040N*    P=0.058N     P=0.585N     P=0.007N**   |
|COCH-ARM / FISHERS |     P=0.486N     P=0.102      P=0.301      P=0.477     |P=0.019N*    P=0.066N     P=0.418N     P=0.004N**   |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 35
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Stomach, Forestomach                                                                                                             |
|     Ulcer                                                                                                                       |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/50 (0%)    0/49 (0%)    1/49 (2%)   |1/49 (2%)    1/50 (2%)    0/50 (0%)    2/49 (4%)    |
|POLY-3 ADJUSTED (b)|     4.5%         0.0%         0.0%         2.3%        |2.2%         2.2%         0.0%         4.7%         |
|TERMINAL (d)       |     1/35 (3%)    0/38 (0%)    0/34 (0%)    1/34 (3%)   |1/36 (3%)    0/34 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     462          ---          ---          733 (T)     |735 (T)      715          ---          497          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.543N     P=0.226N     P=0.243N     P=0.504N    |P=0.335      P=0.757      P=0.530N     P=0.463      |
|POLY 3             |     P=0.546N     P=0.231N     P=0.248N     P=0.502N    |P=0.353      P=0.758N     P=0.520N     P=0.483      |
|POLY 1.5           |     P=0.543N     P=0.232N     P=0.245N     P=0.501N    |P=0.361      P=0.759N     P=0.513N     P=0.489      |
|POLY 6             |     P=0.550N     P=0.229N     P=0.251N     P=0.502N    |P=0.347      P=0.756N     P=0.526N     P=0.478      |
|LOGISTIC REGRESSION|     P=0.558N     P=0.286N     P=0.252N     P=0.550N    |P=0.406      P=0.759N     (e)          P=0.693      |
|COCH-ARM / FISHERS |     P=0.536N     P=0.247N     P=0.253N     P=0.508N    |P=0.372      P=0.747N     P=0.495N     P=0.500      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Stomach, Forestomach: Epithelium                                                                                                 |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     6/50 (12%)   2/50 (4%)    3/49 (6%)    3/49 (6%)   |2/49 (4%)    6/50 (12%)   1/50 (2%)    2/49 (4%)    |
|POLY-3 ADJUSTED (b)|     13.5%        4.4%         7.0%         6.7%        |4.4%         13.0%        2.5%         4.8%         |
|TERMINAL (d)       |     4/35 (11%)   1/38 (3%)    2/34 (6%)    2/34 (6%)   |1/36 (3%)    3/34 (9%)    1/31 (3%)    0/29 (0%)    |
|FIRST INCIDENCE    |     647          710          645          656         |617          533          735 (T)      595          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.355N     P=0.113N     P=0.269N     P=0.253N    |P=0.276N     P=0.137      P=0.551N     P=0.639      |
|POLY 3             |     P=0.339N     P=0.121N     P=0.258N     P=0.237N    |P=0.242N     P=0.139      P=0.537N     P=0.666      |
|POLY 1.5           |     P=0.337N     P=0.124N     P=0.254N     P=0.239N    |P=0.229N     P=0.137      P=0.524N     P=0.676      |
|POLY 6             |     P=0.343N     P=0.118N     P=0.263N     P=0.236N    |P=0.256N     P=0.142      P=0.550N     P=0.656      |
|LOGISTIC REGRESSION|     P=0.332N     P=0.122N     P=0.255N     P=0.239N    |P=0.203N     P=0.148      P=0.506N     P=0.657N     |
|COCH-ARM / FISHERS |     P=0.336N     P=0.134N     P=0.254N     P=0.254N    |P=0.206N     P=0.141      P=0.492N     P=0.691N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 36
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Stomach, Glandular                                                                                                               |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/49 (0%)    0/50 (0%)    0/49 (0%)    0/48 (0%)   |0/49 (0%)    2/50 (4%)    0/50 (0%)    0/48 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |0.0%         4.4%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/34 (0%)    0/34 (0%)   |0/36 (0%)    1/34 (3%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |---          659          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.295N     P=0.243      (e)          (e)          |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.284N     P=0.241      (e)          (e)          |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.279N     P=0.239      (e)          (e)          |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.288N     P=0.243      (e)          (e)          |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.271N     P=0.243      (e)          (e)          |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.267N     P=0.253      (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Testes                                                                                                                           |
|     Atrophy                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     6/50 (12%)   9/50 (18%)   2/50 (4%)    2/50 (4%)   |                                                    |
|POLY-3 ADJUSTED (b)|     13.5%        19.2%        4.7%         4.4%        |                                                    |
|TERMINAL (d)       |     4/35 (11%)   5/38 (13%)   2/34 (6%)    1/34 (3%)   |                                                    |
|FIRST INCIDENCE    |     561          581          733 (T)      723         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.024N*    P=0.356      P=0.151N     P=0.145N    |                                                    |
|POLY 3             |     P=0.017N*    P=0.324      P=0.144N     P=0.129N    |                                                    |
|POLY 1.5           |     P=0.016N*    P=0.314      P=0.139N     P=0.128N    |                                                    |
|POLY 6             |     P=0.018N*    P=0.338      P=0.152N     P=0.131N    |                                                    |
|LOGISTIC REGRESSION|     P=0.017N*    P=0.292      P=0.138N     P=0.129N    |                                                    |
|COCH-ARM / FISHERS |     P=0.017N*    P=0.288      P=0.134N     P=0.134N    |                                                    |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 37
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     11/50 (22%)  13/50 (26%)  7/50 (14%)   8/48 (17%)  |10/50 (20%)  17/50 (34%)  14/50 (28%)  12/49 (24%)  |
|POLY-3 ADJUSTED (b)|     25.0%        28.0%        16.3%        18.1%       |22.3%        37.1%        34.5%        28.8%        |
|TERMINAL (d)       |     10/35 (29%)  11/38 (29%)  7/34 (21%)   7/34 (21%)  |10/36 (28%)  13/34 (38%)  14/31 (45%)  9/28 (32%)   |
|FIRST INCIDENCE    |     702          581          733 (T)      716         |735 (T)      672          735 (T)      646          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.161N     P=0.502      P=0.234N     P=0.323N    |P=0.321      P=0.067      P=0.112      P=0.194      |
|POLY 3             |     P=0.132N     P=0.466      P=0.230N     P=0.296N    |P=0.490      P=0.092      P=0.154      P=0.326      |
|POLY 1.5           |     P=0.134N     P=0.449      P=0.222N     P=0.306N    |P=0.536      P=0.087      P=0.181      P=0.350      |
|POLY 6             |     P=0.134N     P=0.486      P=0.240N     P=0.289N    |P=0.444      P=0.098      P=0.132      P=0.304      |
|LOGISTIC REGRESSION|     P=0.134N     P=0.473      P=0.244N     P=0.286N    |P=0.384      P=0.087      P=0.112      P=0.261      |
|COCH-ARM / FISHERS |     P=0.145N     P=0.408      P=0.218N     P=0.341N    |P=0.485N     P=0.088      P=0.241      P=0.384      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Tooth                                                                                                                            |
|     Malformation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/1 (100%)   2/3 (67%)    1/1 (100%)   1/1 (100%)  |0/0 (0%)     0/0 (0%)     0/0 (0%)     0/0 (0%)     |
|POLY-3 ADJUSTED (b)|     100.0%       80.1%        100.0%       100.0%      |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     1/1 (100%)   2/2 (100%)   1/1 (100%)   1/1 (100%)  |0/0 (0%)     0/0 (0%)     0/0 (0%)     0/0 (0%)     |
|FIRST INCIDENCE    |     733 (T)      733 (T)      733 (T)      733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=1.000N     P=1.000N     (e)          (e)         |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.719      P=0.895N     (e)          (e)         |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.619      P=0.792N     (e)          (e)         |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.934      P=0.997N     (e)          (e)         |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=1.000N     P=1.000N     (e)          (e)         |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.562      P=0.750N     (e)          (e)         |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 38
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Urinary Bladder                                                                                                                  |
|     Inflammation                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/49 (2%)    0/50 (0%)    0/46 (0%)    2/46 (4%)   |0/48 (0%)    0/48 (0%)    0/50 (0%)    0/48 (0%)    |
|POLY-3 ADJUSTED (b)|     2.3%         0.0%         0.0%         4.6%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/35 (0%)    0/38 (0%)    0/33 (0%)    0/34 (0%)   |0/36 (0%)    0/32 (0%)    0/31 (0%)    0/29 (0%)    |
|FIRST INCIDENCE    |     561          ---          ---          555         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.208      P=0.500N     P=0.509N     P=0.502     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.194      P=0.492N     P=0.517N     P=0.495     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.194      P=0.493N     P=0.514N     P=0.491     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.194      P=0.492N     P=0.520N     P=0.498     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.126      P=0.571N     P=0.567N     P=0.377     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.191      P=0.495N     P=0.516N     P=0.476     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Angiectasis                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |1/49 (2%)    1/50 (2%)    2/50 (4%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|                                                        |2.2%         2.2%         4.9%         0.0%         |
|TERMINAL (d)       |                                                        |0/36 (0%)    1/34 (3%)    2/31 (7%)    0/29 (0%)    |
|FIRST INCIDENCE    |                                                        |533          735 (T)      735 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.430N     P=0.754      P=0.455      P=0.522N     |
|POLY 3             |                                                        |P=0.405N     P=0.760      P=0.461      P=0.515N     |
|POLY 1.5           |                                                        |P=0.391N     P=0.760      P=0.475      P=0.508N     |
|POLY 6             |                                                        |P=0.420N     P=0.760      P=0.449      P=0.523N     |
|LOGISTIC REGRESSION|                                                        |P=0.366N     P=0.729N     P=0.537      P=0.329N     |
|COCH-ARM / FISHERS |                                                        |P=0.370N     P=0.747N     P=0.508      P=0.495N     |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 39
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Hydrometra                                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |2/49 (4%)    4/50 (8%)    3/50 (6%)    4/50 (8%)    |
|POLY-3 ADJUSTED (b)|                                                        |4.5%         8.8%         7.3%         9.4%         |
|TERMINAL (d)       |                                                        |2/36 (6%)    4/34 (12%)   2/31 (7%)    2/29 (7%)    |
|FIRST INCIDENCE    |                                                        |735 (T)      735 (T)      609          595          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.270      P=0.310      P=0.435      P=0.255      |
|POLY 3             |                                                        |P=0.332      P=0.342      P=0.460      P=0.314      |
|POLY 1.5           |                                                        |P=0.349      P=0.340      P=0.474      P=0.325      |
|POLY 6             |                                                        |P=0.316      P=0.344      P=0.450      P=0.303      |
|LOGISTIC REGRESSION|                                                        |P=0.330      P=0.310      P=0.466      P=0.317      |
|COCH-ARM / FISHERS |                                                        |P=0.379      P=0.349      P=0.510      P=0.349      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Hyperplasia Cystic                                                                                                          |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |2/49 (4%)    2/50 (4%)    2/50 (4%)    3/50 (6%)    |
|POLY-3 ADJUSTED (b)|                                                        |4.4%         4.4%         4.9%         7.1%         |
|TERMINAL (d)       |                                                        |1/36 (3%)    1/34 (3%)    1/31 (3%)    3/29 (10%)   |
|FIRST INCIDENCE    |                                                        |684          715          715          735 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.292      P=0.686      P=0.635      P=0.410      |
|POLY 3             |                                                        |P=0.342      P=0.691N     P=0.657      P=0.470      |
|POLY 1.5           |                                                        |P=0.360      P=0.692N     P=0.671      P=0.484      |
|POLY 6             |                                                        |P=0.324      P=0.690N     P=0.645      P=0.454      |
|LOGISTIC REGRESSION|                                                        |P=0.324      P=0.691N     P=0.659      P=0.455      |
|COCH-ARM / FISHERS |                                                        |P=0.387      P=0.684N     P=0.684N     P=0.510      |
|=================================================================================================================================|
       Date:  03/09/99                           EXPERIMENT: 05180 TEST: 07                                            Page 40
                     Statistical Analysis of Non-neoplastic Lesions in       Mice(B6C3F1)  -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.1          0.5          1.0         |CONTROL      0.1          0.5          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus: Myometrium                                                                                                               |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|LESION RATES       |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |2/49 (4%)    0/50 (0%)    2/50 (4%)    2/50 (4%)    |
|POLY-3 ADJUSTED (b)|                                                        |4.5%         0.0%         4.9%         4.7%         |
|TERMINAL (d)       |                                                        |2/36 (6%)    0/34 (0%)    2/31 (7%)    0/29 (0%)    |
|FIRST INCIDENCE    |                                                        |735 (T)      ---          735 (T)      628          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.292      P=0.251N     P=0.641      P=0.631      |
|POLY 3             |                                                        |P=0.331      P=0.235N     P=0.658      P=0.675      |
|POLY 1.5           |                                                        |P=0.344      P=0.236N     P=0.671      P=0.684      |
|POLY 6             |                                                        |P=0.320      P=0.233N     P=0.647      P=0.667      |
|LOGISTIC REGRESSION|                                                        |P=0.329      (e)          P=0.641      P=0.692      |
|COCH-ARM / FISHERS |                                                        |P=0.361      P=0.242N     P=0.684N     P=0.684N     |
|=================================================================================================================================|

(a)  Number of tumor-bearing animals /  number of animals examined at site.
(b)  Poly-3 adjusted lifetime tumor incidence.
(d)  Observed incidence at terminal kill.
(f)  Beneath the control incidence are the P-values associated with the trend 
test.  Beneath the dosed group incidence are the P-values corresponding to 
pairwise comparisons between the controls and that dosed group.  The life
table analysis regards tumors in animals dying prior to  terminal kill as
 being (directly or indirectly) the cause of death.
Logistic regression is an alternative
 method for analyzing the incidence of non-fatal tumors. The Cochran-Armitage
and Fishers exact tests compare directly the overall incidence rates
For all tests a negative trend is indicated by N
(e)  Value of Statistic cannot be computed.
(I)  Interim sacrifice
(T)  Terminal sacrifice
#   Tumor rates based on number of animals necropsied.
*   To the right of any statistical result, indicates significance at (P<=0.05).
**  To the right of any statistical result, indicates significance at (P<=0.01).