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TDMS Study 05180-06 Pathology Tables

NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Northwest                                     GALLIUM ARSENIDE                                   DATE: 02/17/99       
EXPERIMENT: 05180 TEST: 06                                                                                     TIME: 08:15:51       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: NO1-ES-25335                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 62033B       
PATHOLOGIST: GRUMBEIN, S.                                                                                      CAS: 1303-00-0000    
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    
                                                        2 YEAR CHRONIC RATS                                                         
                                                                                                                                    

               REASONS FOR REMOVAL:    ALL                                                                                          
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       INCLUDE ALL                                                                                  
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08
LAB: Battelle Northwest                                     GALLIUM ARSENIDE                                   DATE: 02/17/99

EXPERIMENT: 05180 TEST: 06                                                                                     TIME: 08:15:51
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE
CONT: NO1-ES-25335                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 62033B
PATHOLOGIST: GRUMBEIN, S.                                                                                      CAS: 1303-00-0000

Rats(FISCHER 344)
-----------------------------
FOR ALL DOSES THE TUMOR RATES IN THE FOLLOWING TISSUES/ORGANS ARE
BASED ON NUMBER OF TISSUES EXAMINED.  IN OTHER TISSUES/ORGANS RATES
ARE BASED ON THE NUMBER OF ANIMALS NECROPSIED.
                                                 ---------------
                                                 Adrenal Medulla
                                                 Brain
                                                 Clitoral/Preputial Gland
                                                 Heart
                                                 Islets, Pancreatic
                                                 Kidney
                                                 Liver
                                                 Lung
                                                 Ovary
                                                 Pancreas
                                                 Pituitary Gland
                                                 Prostate
                                                 Spleen
                                                 Testes
                                                 Thymus
                                                 Thyroid Gland
                                                 Urinary Bladder
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08   
LAB: Battelle Northwest                                     GALLIUM ARSENIDE                                   DATE: 02/17/99     
EXPERIMENT: 05180 TEST: 06                                                                                     TIME: 08:15:51     
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                      
CONT: NO1-ES-25335                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 62033B     
PATHOLOGIST: GRUMBEIN, S.                                                                                      CAS: 1303-00-0000  



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

Male Rats
------------
Organ                                 Morphology
-----                                 ----------
Clitoral/Preputial Gland               Adenoma
All Organs                             Hemangioma
                                       Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                       Malignant Tumors
===============================================================
Female Rats
------------
Organ                                  Morphology
-----                                  ----------
Adrenal Medulla                        Pheochromocytoma Benign
                                       Pheochromocytoma: Benign, Complex, Malignant, NOS
Islets, Pancreatic                     Carcinoma or Adenoma
Lung                                   Alveolar/Bronchiolar Adenoma
                                       Alveolar/Bronchiolar Carcinoma
                                       Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma
Mammary Gland                          Fibroadenoma
                                       Fibroma, Fibroadenoma or Adenoma
                                       Fibroma, Fibroadenoma, Carcinoma, or Adenoma
Pituitary Gland: Pars Distalis or Unspecified Site
                                       Adenoma
Thyroid Gland: C-Cell                  Adenoma
All Organs                             Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                       Malignant Tumors
                                       Malignant and Benign Tumors
===============================================================
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 1
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)        -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Benign                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     16/50 (32%)  12/49 (24%)  22/49 (45%)  13/50 (26%) |4/50 (8%)    5/49 (10%)   6/50 (12%)   13/49 (27%)  |
|POLY-3 ADJUSTED (b)|     40.8%        33.0%        54.8%        35.3%       |9.9%         13.3%        16.0%        36.0%        |
|TERMINAL (d)       |     5/13 (39%)   4/13 (31%)   9/15 (60%)   7/13 (54%)  |1/19 (5%)    2/16 (13%)   5/21 (24%)   4/11 (36%)   |
|FIRST INCIDENCE    |     567          614          590          547         |506          695          674          564          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.347N     P=0.342N     P=0.284      P=0.376N    |P<0.001 **   P=0.447      P=0.390      P=0.002 **   |
|POLY 3             |     P=0.297N     P=0.314N     P=0.140      P=0.395N    |P<0.001 **   P=0.455      P=0.321      P=0.005 **   |
|POLY 1.5           |     P=0.271N     P=0.303N     P=0.133      P=0.368N    |P=0.002 **   P=0.469      P=0.336      P=0.007 **   |
|POLY 6             |     P=0.344N     P=0.316N     P=0.162      P=0.434N    |P<0.001 **   P=0.441      P=0.309      P=0.003 **   |
|LOGISTIC REGRESSION|     P=0.314N     P=0.334N     P=0.165      P=0.404N    |P<0.001 **   P=0.463      P=0.329      P=0.007 **   |
|COCH-ARM / FISHERS |     P=0.251N     P=0.272N     P=0.133      P=0.330N    |P=0.004 **   P=0.487      P=0.370      P=0.014 *    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Malignant                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/49 (0%)    3/49 (6%)    1/50 (2%)   |0/50 (0%)    1/49 (2%)    0/50 (0%)    0/49 (0%)    |
|POLY-3 ADJUSTED (b)|     5.4%         0.0%         8.0%         2.9%        |0.0%         2.7%         0.0%         0.0%         |
|TERMINAL (d)       |     1/13 (8%)    0/13 (0%)    2/15 (13%)   0/13 (0%)   |0/19 (0%)    1/16 (6%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     671          ---          601          713         |---          734 (T)      ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.549N     P=0.259N     P=0.555      P=0.527N    |P=0.768N     P=0.466      (e)          (e)          |
|POLY 3             |     P=0.537N     P=0.254N     P=0.508      P=0.519N    |P=0.682N     P=0.489      (e)          (e)          |
|POLY 1.5           |     P=0.532N     P=0.250N     P=0.500      P=0.512N    |P=0.677N     P=0.492      (e)          (e)          |
|POLY 6             |     P=0.542N     P=0.258N     P=0.521      P=0.527N    |P=0.689N     P=0.485      (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.554N     P=0.256N     P=0.517      P=0.524N    |(e)          P=0.466      (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.528N     P=0.253N     P=0.490      P=0.500N    |P=0.671N     P=0.495      (e)          (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 2
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma: Benign, Complex, Malignant, NOS                                                                           |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     16/50 (32%)  12/49 (24%)  23/49 (47%)  14/50 (28%) |4/50 (8%)    6/49 (12%)   6/50 (12%)   13/49 (27%)  |
|POLY-3 ADJUSTED (b)|     40.8%        33.0%        56.7%        38.0%       |9.9%         16.0%        16.0%        36.0%        |
|TERMINAL (d)       |     5/13 (39%)   4/13 (31%)   9/15 (60%)   7/13 (54%)  |1/19 (5%)    3/16 (19%)   5/21 (24%)   4/11 (36%)   |
|FIRST INCIDENCE    |     567          614          590          547         |506          695          674          564          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.418N     P=0.342N     P=0.233      P=0.459N    |P<0.001 **   P=0.317      P=0.390      P=0.002 **   |
|POLY 3             |     P=0.380N     P=0.314N     P=0.103      P=0.492N    |P=0.002 **   P=0.323      P=0.321      P=0.005 **   |
|POLY 1.5           |     P=0.347N     P=0.303N     P=0.096      P=0.459N    |P=0.003 **   P=0.338      P=0.336      P=0.007 **   |
|POLY 6             |     P=0.438N     P=0.316N     P=0.127      P=0.536N    |P=0.002 **   P=0.308      P=0.309      P=0.003 **   |
|LOGISTIC REGRESSION|     P=0.395N     P=0.334N     P=0.115      P=0.502N    |P<0.001 **   P=0.328      P=0.329      P=0.007 **   |
|COCH-ARM / FISHERS |     P=0.318N     P=0.272N     P=0.094      P=0.414N    |P=0.006 **   P=0.357      P=0.370      P=0.014 *    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Bone                                                                                                                             |
|     Osteosarcoma                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    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)|     2.7%         0.0%         5.2%         0.0%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     567          ---          562          ---         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.427N     P=0.510N     P=0.512      P=0.515N    |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.402N     P=0.517N     P=0.511      P=0.513N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.400N     P=0.512N     P=0.506      P=0.508N    |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.406N     P=0.523N     P=0.521      P=0.519N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.395N     P=0.454N     P=0.489      P=0.466N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.400N     P=0.500N     P=0.500      P=0.500N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 3
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/49 (4%)    3/50 (6%)    6/49 (12%)  |8/50 (16%)   9/48 (19%)   7/47 (15%)   4/48 (8%)    |
|POLY-3 ADJUSTED (b)|     0.0%         5.9%         7.8%         16.7%       |19.6%        23.5%        19.7%        11.9%        |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    1/15 (7%)    3/13 (23%)  |4/19 (21%)   4/16 (25%)   5/20 (25%)   0/10 (0%)    |
|FIRST INCIDENCE    |     ---          574          604          520         |581          590          631          632          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.017 *    P=0.237      P=0.141      P=0.018 *   |P=0.333N     P=0.413      P=0.502N     P=0.424N     |
|POLY 3             |     P=0.016 *    P=0.218      P=0.126      P=0.013 *   |P=0.174N     P=0.444      P=0.610      P=0.279N     |
|POLY 1.5           |     P=0.016 *    P=0.222      P=0.122      P=0.013 *   |P=0.150N     P=0.454      P=0.597N     P=0.247N     |
|POLY 6             |     P=0.015 *    P=0.215      P=0.132      P=0.012 *   |P=0.205N     P=0.434      P=0.601      P=0.317N     |
|LOGISTIC REGRESSION|     P=0.017 *    P=0.224      P=0.120      P=0.015 *   |P=0.178N     P=0.445      P=0.605N     P=0.265N     |
|COCH-ARM / FISHERS |     P=0.017 *    P=0.242      P=0.121      P=0.012 *   |P=0.113N     P=0.463      P=0.552N     P=0.199N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     4/50 (8%)    4/49 (8%)    5/50 (10%)   4/49 (8%)   |3/50 (6%)    2/48 (4%)    2/47 (4%)    2/48 (4%)    |
|POLY-3 ADJUSTED (b)|     10.6%        11.7%        12.8%        11.1%       |7.5%         5.3%         5.7%         6.1%         |
|TERMINAL (d)       |     1/13 (8%)    2/13 (15%)   0/15 (0%)    1/13 (8%)   |2/19 (11%)   1/16 (6%)    2/20 (10%)   1/10 (10%)   |
|FIRST INCIDENCE    |     534          567          590          540         |582          559          734 (T)      684          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.601      P=0.616      P=0.549      P=0.605     |P=0.540      P=0.561N     P=0.490N     P=0.662      |
|POLY 3             |     P=0.582N     P=0.592      P=0.525      P=0.621     |P=0.623N     P=0.527N     P=0.563N     P=0.589N     |
|POLY 1.5           |     P=0.577N     P=0.603      P=0.512      P=0.624     |P=0.600N     P=0.522N     P=0.553N     P=0.563N     |
|POLY 6             |     P=0.589N     P=0.582      P=0.550      P=0.622     |P=0.631      P=0.533N     P=0.570N     P=0.620N     |
|LOGISTIC REGRESSION|     P=0.575N     P=0.609      P=0.497      P=0.636     |P=0.636N     P=0.520N     P=0.559N     P=0.601N     |
|COCH-ARM / FISHERS |     P=0.575N     P=0.631      P=0.500      P=0.631     |P=0.562N     P=0.520N     P=0.530N     P=0.520N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 4
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     4/50 (8%)    6/49 (12%)   8/50 (16%)   10/49 (20%) |11/50 (22%)  11/48 (23%)  9/47 (19%)   6/48 (13%)   |
|POLY-3 ADJUSTED (b)|     10.6%        17.3%        20.0%        26.8%       |26.7%        28.3%        25.3%        17.8%        |
|TERMINAL (d)       |     1/13 (8%)    3/13 (23%)   1/15 (7%)    4/13 (31%)  |6/19 (32%)   5/16 (31%)   7/20 (35%)   1/10 (10%)   |
|FIRST INCIDENCE    |     534          567          590          520         |581          559          631          632          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.086      P=0.349      P=0.235      P=0.073     |P=0.410N     P=0.482      P=0.398N     P=0.446N     |
|POLY 3             |     P=0.092      P=0.315      P=0.202      P=0.062     |P=0.193N     P=0.536      P=0.552N     P=0.260N     |
|POLY 1.5           |     P=0.093      P=0.327      P=0.189      P=0.063     |P=0.161N     P=0.545      P=0.523N     P=0.221N     |
|POLY 6             |     P=0.089      P=0.307      P=0.228      P=0.061     |P=0.233N     P=0.528      P=0.577N     P=0.307N     |
|LOGISTIC REGRESSION|     P=0.092      P=0.330      P=0.176      P=0.067     |P=0.197N     P=0.538      P=0.527N     P=0.251N     |
|COCH-ARM / FISHERS |     P=0.093      P=0.357      P=0.178      P=0.068     |P=0.116N     P=0.553      P=0.463N     P=0.165N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/48 (4%)    1/49 (2%)    2/50 (4%)    2/50 (4%)   |1/50 (2%)    0/50 (0%)    0/50 (0%)    2/49 (4%)    |
|POLY-3 ADJUSTED (b)|     5.6%         2.9%         5.3%         5.6%        |2.5%         0.0%         0.0%         5.8%         |
|TERMINAL (d)       |     1/13 (8%)    1/13 (8%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     671          733 (T)      704          601         |685          ---          ---          691          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.539      P=0.520N     P=0.661N     P=0.660     |P=0.127      P=0.480N     P=0.539N     P=0.443      |
|POLY 3             |     P=0.572      P=0.517N     P=0.676N     P=0.695     |P=0.139      P=0.507N     P=0.513N     P=0.449      |
|POLY 1.5           |     P=0.573      P=0.508N     P=0.677N     P=0.690N    |P=0.145      P=0.504N     P=0.509N     P=0.465      |
|POLY 6             |     P=0.573      P=0.528N     P=0.674N     P=0.692     |P=0.134      P=0.510N     P=0.515N     P=0.432      |
|LOGISTIC REGRESSION|     P=0.554      P=0.528N     P=0.670N     P=0.694N    |P=0.130      P=0.504N     P=0.509N     P=0.445      |
|COCH-ARM / FISHERS |     P=0.577      P=0.492N     P=0.676N     P=0.676N    |P=0.155      P=0.500N     P=0.500N     P=0.492      |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 5
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/48 (0%)    3/49 (6%)    0/50 (0%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    1/49 (2%)    |
|POLY-3 ADJUSTED (b)|     0.0%         8.7%         0.0%         2.9%        |0.0%         0.0%         0.0%         2.9%         |
|TERMINAL (d)       |     0/13 (0%)    2/13 (15%)   0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          532          ---          733 (T)     |---          ---          ---          688          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.688N     P=0.117      (e)          P=0.500     |P=0.231      (e)          (e)          P=0.468      |
|POLY 3             |     P=0.691N     P=0.112      (e)          P=0.496     |P=0.237      (e)          (e)          P=0.471      |
|POLY 1.5           |     P=0.681N     P=0.116      (e)          P=0.501     |P=0.243      (e)          (e)          P=0.480      |
|POLY 6             |     P=0.702N     P=0.109      (e)          P=0.491     |P=0.231      (e)          (e)          P=0.461      |
|LOGISTIC REGRESSION|     P=0.682N     P=0.115      (e)          P=0.500     |P=0.234      (e)          (e)          P=0.469      |
|COCH-ARM / FISHERS |     P=0.664N     P=0.125      (e)          P=0.510     |P=0.253      (e)          (e)          P=0.495      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/48 (4%)    4/49 (8%)    2/50 (4%)    3/50 (6%)   |1/50 (2%)    0/50 (0%)    0/50 (0%)    3/49 (6%)    |
|POLY-3 ADJUSTED (b)|     5.6%         11.5%        5.3%         8.4%        |2.5%         0.0%         0.0%         8.7%         |
|TERMINAL (d)       |     1/13 (8%)    3/13 (23%)   0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     671          532          704          601         |685          ---          ---          688          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.547      P=0.317      P=0.661N     P=0.468     |P=0.028 *    P=0.480N     P=0.539N     P=0.252      |
|POLY 3             |     P=0.570      P=0.321      P=0.676N     P=0.499     |P=0.032 *    P=0.507N     P=0.513N     P=0.256      |
|POLY 1.5           |     P=0.577      P=0.329      P=0.677N     P=0.506     |P=0.034 *    P=0.504N     P=0.509N     P=0.270      |
|POLY 6             |     P=0.564      P=0.310      P=0.674N     P=0.493     |P=0.030 *    P=0.510N     P=0.515N     P=0.241      |
|LOGISTIC REGRESSION|     P=0.562      P=0.308      P=0.670N     P=0.491     |P=0.028 *    P=0.504N     P=0.509N     P=0.250      |
|COCH-ARM / FISHERS |     P=0.590      P=0.349      P=0.676N     P=0.520     |P=0.039 *    P=0.500N     P=0.500N     P=0.301      |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 6
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/49 (4%)    0/50 (0%)    0/50 (0%)    3/50 (6%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    0/49 (0%)    |
|POLY-3 ADJUSTED (b)|     5.4%         0.0%         0.0%         8.5%        |0.0%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    2/13 (15%)  |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     590          ---          ---          604         |---          ---          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.099      P=0.257N     P=0.227N     P=0.488     |P=0.841N     (e)          P=0.520      (e)          |
|POLY 3             |     P=0.103      P=0.253N     P=0.231N     P=0.481     |P=0.764N     (e)          P=0.488      (e)          |
|POLY 1.5           |     P=0.104      P=0.246N     P=0.232N     P=0.493     |P=0.758N     (e)          P=0.491      (e)          |
|POLY 6             |     P=0.101      P=0.261N     P=0.231N     P=0.469     |P=0.771N     (e)          P=0.487      (e)          |
|LOGISTIC REGRESSION|     P=0.100      P=0.230N     P=0.235N     P=0.489     |(e)          (e)          P=0.520      (e)          |
|COCH-ARM / FISHERS |     P=0.106      P=0.242N     P=0.242N     P=0.510     |P=0.747N     (e)          P=0.500      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma or Hepatocellular Adenoma                                                                          |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    1/50 (2%)    2/50 (4%)    0/50 (0%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     2.7%         2.9%         5.3%         0.0%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    1/15 (7%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     726          733 (T)      698          ---         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.296N     P=0.745      P=0.546      P=0.514N    |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.302N     P=0.745      P=0.509      P=0.510N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.298N     P=0.750      P=0.505      P=0.506N    |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.306N     P=0.742      P=0.518      P=0.514N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.300N     P=0.751      P=0.526      P=0.508N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.294N     P=0.753N     P=0.500      P=0.500N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 7
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma, Hepatocellular Adenoma,                                                                           |
|     or Hepatoblastoma                                                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    1/50 (2%)    2/50 (4%)    0/50 (0%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     2.7%         2.9%         5.3%         0.0%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    1/15 (7%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     726          733 (T)      698          ---         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.296N     P=0.745      P=0.546      P=0.514N    |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.302N     P=0.745      P=0.509      P=0.510N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.298N     P=0.750      P=0.505      P=0.506N    |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.306N     P=0.742      P=0.518      P=0.514N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.300N     P=0.751      P=0.526      P=0.508N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.294N     P=0.753N     P=0.500      P=0.500N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Adenoma                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    0/49 (0%)    3/50 (6%)    2/50 (4%)   |0/50 (0%)    0/50 (0%)    2/50 (4%)    7/50 (14%)   |
|POLY-3 ADJUSTED (b)|     2.7%         0.0%         8.0%         5.7%        |0.0%         0.0%         5.3%         19.7%        |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    3/15 (20%)   2/13 (15%)  |0/19 (0%)    0/17 (0%)    1/21 (5%)    2/11 (18%)   |
|FIRST INCIDENCE    |     688          ---          733 (T)      733 (T)     |---          ---          646          556          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.412      P=0.490N     P=0.357      P=0.506     |P<0.001 **   (e)          P=0.244      P=0.003 **   |
|POLY 3             |     P=0.421      P=0.516N     P=0.310      P=0.481     |P<0.001 **   (e)          P=0.225      P=0.004 **   |
|POLY 1.5           |     P=0.426      P=0.512N     P=0.308      P=0.488     |P<0.001 **   (e)          P=0.228      P=0.005 **   |
|POLY 6             |     P=0.416      P=0.520N     P=0.314      P=0.473     |P<0.001 **   (e)          P=0.225      P=0.003 **   |
|LOGISTIC REGRESSION|     P=0.410      P=0.517N     P=0.328      P=0.480     |P<0.001 **   (e)          P=0.226      P=0.005 **   |
|COCH-ARM / FISHERS |     P=0.431      P=0.505N     P=0.309      P=0.500     |P<0.001 **   (e)          P=0.247      P=0.006 **   |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 8
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma                                                                                              |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/49 (0%)    2/50 (4%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    2/50 (4%)    3/50 (6%)    |
|POLY-3 ADJUSTED (b)|     5.4%         0.0%         5.3%         2.9%        |0.0%         0.0%         5.4%         8.6%         |
|TERMINAL (d)       |     1/13 (8%)    0/13 (0%)    1/15 (7%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    2/21 (10%)   1/11 (9%)    |
|FIRST INCIDENCE    |     567          ---          722          733 (T)     |---          ---          734 (T)      677          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.629N     P=0.245N     P=0.659N     P=0.509N    |P=0.024 *    (e)          P=0.259      P=0.077      |
|POLY 3             |     P=0.617N     P=0.256N     P=0.692N     P=0.523N    |P=0.053      (e)          P=0.224      P=0.097      |
|POLY 1.5           |     P=0.613N     P=0.251N     P=0.693N     P=0.514N    |P=0.059      (e)          P=0.227      P=0.104      |
|POLY 6             |     P=0.623N     P=0.261N     P=0.689N     P=0.533N    |P=0.048 *    (e)          P=0.221      P=0.089      |
|LOGISTIC REGRESSION|     P=0.632N     P=0.245N     P=0.683N     P=0.518N    |P=0.037 *    (e)          P=0.259      P=0.087      |
|COCH-ARM / FISHERS |     P=0.609N     P=0.253N     P=0.691N     P=0.500N    |P=0.070      (e)          P=0.247      P=0.121      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar                                                                      |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    0/49 (0%)    5/50 (10%)   3/50 (6%)   |0/50 (0%)    0/50 (0%)    4/50 (8%)    9/50 (18%)   |
|POLY-3 ADJUSTED (b)|     8.0%         0.0%         13.3%        8.6%        |0.0%         0.0%         10.7%        25.0%        |
|TERMINAL (d)       |     1/13 (8%)    0/13 (0%)    4/15 (27%)   3/13 (23%)  |0/19 (0%)    0/17 (0%)    3/21 (14%)   2/11 (18%)   |
|FIRST INCIDENCE    |     567          ---          722          733 (T)     |---          ---          646          556          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.479      P=0.124N     P=0.423      P=0.663     |P<0.001 **   (e)          P=0.071      P<0.001 **   |
|POLY 3             |     P=0.490      P=0.134N     P=0.357      P=0.632     |P<0.001 **   (e)          P=0.053      P<0.001 **   |
|POLY 1.5           |     P=0.498      P=0.130N     P=0.357      P=0.644     |P<0.001 **   (e)          P=0.055      P<0.001 **   |
|POLY 6             |     P=0.480      P=0.139N     P=0.357      P=0.617     |P<0.001 **   (e)          P=0.052      P<0.001 **   |
|LOGISTIC REGRESSION|     P=0.471      P=0.130N     P=0.387      P=0.634     |P<0.001 **   (e)          P=0.054      P<0.001 **   |
|COCH-ARM / FISHERS |     P=0.505      P=0.125N     P=0.357      P=0.661N    |P<0.001 **   (e)          P=0.059      P<0.001 **   |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 9
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)   |8/50 (16%)   3/50 (6%)    7/50 (14%)   5/50 (10%)   |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         2.9%        |19.8%        7.7%         18.7%        14.2%        |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |4/19 (21%)   1/17 (6%)    6/21 (29%)   1/11 (9%)    |
|FIRST INCIDENCE    |     ---          ---          ---          668         |589          559          701          632          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.248      (e)          (e)          P=0.483     |P=0.446      P=0.130N     P=0.477N     P=0.523N     |
|POLY 3             |     P=0.256      (e)          (e)          P=0.491     |P=0.549N     P=0.105N     P=0.569N     P=0.368N     |
|POLY 1.5           |     P=0.257      (e)          (e)          P=0.494     |P=0.516N     P=0.102N     P=0.546N     P=0.333N     |
|POLY 6             |     P=0.256      (e)          (e)          P=0.490     |P=0.588N     P=0.108N     P=0.594N     P=0.411N     |
|LOGISTIC REGRESSION|     P=0.252      (e)          (e)          P=0.492     |P=0.588N     P=0.106N     P=0.558N     P=0.392N     |
|COCH-ARM / FISHERS |     P=0.257      (e)          (e)          P=0.500     |P=0.457N     P=0.100N     P=0.500N     P=0.277N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)   |8/50 (16%)   3/50 (6%)    7/50 (14%)   6/50 (12%)   |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         2.9%        |19.8%        7.7%         18.7%        16.9%        |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |4/19 (21%)   1/17 (6%)    6/21 (29%)   1/11 (9%)    |
|FIRST INCIDENCE    |     ---          ---          ---          668         |589          559          701          632          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.248      (e)          (e)          P=0.483     |P=0.292      P=0.130N     P=0.477N     P=0.579      |
|POLY 3             |     P=0.256      (e)          (e)          P=0.491     |P=0.488      P=0.105N     P=0.569N     P=0.491N     |
|POLY 1.5           |     P=0.257      (e)          (e)          P=0.494     |P=0.520      P=0.102N     P=0.546N     P=0.453N     |
|POLY 6             |     P=0.256      (e)          (e)          P=0.490     |P=0.454      P=0.108N     P=0.594N     P=0.534N     |
|LOGISTIC REGRESSION|     P=0.252      (e)          (e)          P=0.492     |P=0.449      P=0.106N     P=0.558N     P=0.518N     |
|COCH-ARM / FISHERS |     P=0.257      (e)          (e)          P=0.500     |P=0.578      P=0.100N     P=0.500N     P=0.387N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 10
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroadenoma                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/50 (4%)    3/50 (6%)    2/50 (4%)   |26/50 (52%)  31/50 (62%)  29/50 (58%)  31/50 (62%)  |
|POLY-3 ADJUSTED (b)|     0.0%         5.8%         7.9%         5.6%        |59.2%        71.3%        68.0%        74.3%        |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |11/19 (58%)  13/17 (77%)  16/21 (76%)  7/11 (64%)   |
|FIRST INCIDENCE    |     ---          660          601          422         |497          422          339          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.516      P=0.217      P=0.150      P=0.240     |P=0.018 *    P=0.173      P=0.391      P=0.025 *    |
|POLY 3             |     P=0.521      P=0.222      P=0.125      P=0.230     |P=0.184      P=0.152      P=0.252      P=0.090      |
|POLY 1.5           |     P=0.524      P=0.226      P=0.122      P=0.233     |P=0.223      P=0.178      P=0.280      P=0.122      |
|POLY 6             |     P=0.519      P=0.219      P=0.131      P=0.228     |P=0.158      P=0.128      P=0.223      P=0.069      |
|LOGISTIC REGRESSION|     P=0.524      P=0.217      P=0.122      P=0.266     |P=0.172      P=0.172      P=0.264      P=0.096      |
|COCH-ARM / FISHERS |     P=0.527      P=0.247      P=0.121      P=0.247     |P=0.329      P=0.210      P=0.344      P=0.210      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma or Adenoma                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/50 (4%)    3/50 (6%)    2/50 (4%)   |26/50 (52%)  31/50 (62%)  29/50 (58%)  31/50 (62%)  |
|POLY-3 ADJUSTED (b)|     0.0%         5.8%         7.9%         5.6%        |59.2%        71.3%        68.0%        74.3%        |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |11/19 (58%)  13/17 (77%)  16/21 (76%)  7/11 (64%)   |
|FIRST INCIDENCE    |     ---          660          601          422         |497          422          339          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.516      P=0.217      P=0.150      P=0.240     |P=0.018 *    P=0.173      P=0.391      P=0.025 *    |
|POLY 3             |     P=0.521      P=0.222      P=0.125      P=0.230     |P=0.184      P=0.152      P=0.252      P=0.090      |
|POLY 1.5           |     P=0.524      P=0.226      P=0.122      P=0.233     |P=0.223      P=0.178      P=0.280      P=0.122      |
|POLY 6             |     P=0.519      P=0.219      P=0.131      P=0.228     |P=0.158      P=0.128      P=0.223      P=0.069      |
|LOGISTIC REGRESSION|     P=0.524      P=0.217      P=0.122      P=0.266     |P=0.172      P=0.172      P=0.264      P=0.096      |
|COCH-ARM / FISHERS |     P=0.527      P=0.247      P=0.121      P=0.247     |P=0.329      P=0.210      P=0.344      P=0.210      |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 11
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma, Carcinoma, or Adenoma                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/50 (4%)    3/50 (6%)    3/50 (6%)   |29/50 (58%)  32/50 (64%)  31/50 (62%)  32/50 (64%)  |
|POLY-3 ADJUSTED (b)|     0.0%         5.8%         7.9%         8.4%        |65.4%        72.7%        72.7%        76.0%        |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |12/19 (63%)  13/17 (77%)  18/21 (86%)  7/11 (64%)   |
|FIRST INCIDENCE    |     ---          660          601          422         |497          422          339          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.278      P=0.217      P=0.150      P=0.119     |P=0.026 *    P=0.269      P=0.453      P=0.045 *    |
|POLY 3             |     P=0.283      P=0.222      P=0.125      P=0.113     |P=0.264      P=0.295      P=0.295      P=0.183      |
|POLY 1.5           |     P=0.286      P=0.226      P=0.122      P=0.115     |P=0.307      P=0.319      P=0.337      P=0.228      |
|POLY 6             |     P=0.282      P=0.219      P=0.131      P=0.112     |P=0.240      P=0.267      P=0.240      P=0.152      |
|LOGISTIC REGRESSION|     P=0.284      P=0.217      P=0.122      P=0.132     |P=0.232      P=0.296      P=0.312      P=0.171      |
|COCH-ARM / FISHERS |     P=0.288      P=0.247      P=0.121      P=0.121     |P=0.423      P=0.341      P=0.419      P=0.341      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Papilloma Squamous or Papilloma                                                                                             |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    3/50 (6%)    1/50 (2%)    2/50 (4%)   |1/50 (2%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     2.7%         8.5%         2.7%         5.7%        |2.5%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     662          524          702          702         |699          ---          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.584      P=0.272      P=0.738N     P=0.494     |P=0.594N     P=0.500N     P=0.758      P=0.563N     |
|POLY 3             |     P=0.572      P=0.286      P=0.757N     P=0.481     |P=0.520N     P=0.507N     P=0.747      P=0.528N     |
|POLY 1.5           |     P=0.581      P=0.291      P=0.759N     P=0.488     |P=0.512N     P=0.504N     P=0.751      P=0.517N     |
|POLY 6             |     P=0.561      P=0.284      P=0.754N     P=0.474     |P=0.532N     P=0.510N     P=0.745      P=0.541N     |
|LOGISTIC REGRESSION|     P=0.586      P=0.307      P=0.757N     P=0.476     |P=0.553N     P=0.507N     P=0.749      P=0.537N     |
|COCH-ARM / FISHERS |     P=0.595      P=0.309      P=0.753N     P=0.500     |P=0.497N     P=0.500N     P=0.753N     P=0.500N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 12
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)   |0/50 (0%)    2/50 (4%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     2.7%         0.0%         0.0%         0.0%        |0.0%         5.2%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     506          ---          ---          ---         |---          695          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.661N     P=0.513N     P=0.508N     P=0.508N    |P=0.499N     P=0.244      (e)          (e)          |
|POLY 3             |     P=0.660N     P=0.518N     P=0.499N     P=0.514N    |P=0.463N     P=0.231      (e)          (e)          |
|POLY 1.5           |     P=0.659N     P=0.512N     P=0.500N     P=0.508N    |P=0.454N     P=0.234      (e)          (e)          |
|POLY 6             |     P=0.662N     P=0.524N     P=0.497N     P=0.519N    |P=0.473N     P=0.230      (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.667N     P=0.403N     P=0.521N     P=0.437N    |P=0.476N     P=0.230      (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.660N     P=0.500N     P=0.500N     P=0.500N    |P=0.443N     P=0.247      (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma, Papilloma Squamous, or Papilloma                                                                   |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    3/50 (6%)    1/50 (2%)    2/50 (4%)   |1/50 (2%)    2/50 (4%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     5.3%         8.5%         2.7%         5.7%        |2.5%         5.2%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     506          524          702          702         |699          695          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.631N     P=0.457      P=0.482N     P=0.684     |P=0.336N     P=0.504      P=0.758      P=0.563N     |
|POLY 3             |     P=0.650N     P=0.469      P=0.499N     P=0.669     |P=0.288N     P=0.491      P=0.747      P=0.528N     |
|POLY 1.5           |     P=0.637N     P=0.478      P=0.500N     P=0.679     |P=0.276N     P=0.495      P=0.751      P=0.517N     |
|POLY 6             |     P=0.642      P=0.463      P=0.497N     P=0.659     |P=0.303N     P=0.488      P=0.745      P=0.541N     |
|LOGISTIC REGRESSION|     P=0.624N     P=0.538      P=0.507N     P=0.691     |P=0.299N     P=0.488      P=0.749      P=0.537N     |
|COCH-ARM / FISHERS |     P=0.622N     P=0.500      P=0.500N     P=0.691N    |P=0.258N     P=0.500      P=0.753N     P=0.500N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 13
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Mucosa                                                                                                                      |
|     Squamous Cell Carcinoma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)   |0/50 (0%)    2/50 (4%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         0.0%        |0.0%         5.2%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          ---         |---          695          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     (e)          (e)          (e)          (e)         |P=0.499N     P=0.244      (e)          (e)          |
|POLY 3             |     (e)          (e)          (e)          (e)         |P=0.463N     P=0.231      (e)          (e)          |
|POLY 1.5           |     (e)          (e)          (e)          (e)         |P=0.454N     P=0.234      (e)          (e)          |
|POLY 6             |     (e)          (e)          (e)          (e)         |P=0.473N     P=0.230      (e)          (e)          |
|LOGISTIC REGRESSION|     (e)          (e)          (e)          (e)         |P=0.476N     P=0.230      (e)          (e)          |
|COCH-ARM / FISHERS |     (e)          (e)          (e)          (e)         |P=0.443N     P=0.247      (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Mucosa                                                                                                                      |
|     Squamous Cell Papilloma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    3/50 (6%)    0/50 (0%)    1/50 (2%)   |1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         8.5%         0.0%         2.9%        |2.5%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          524          ---          733 (T)     |699          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.692N     P=0.114      (e)          P=0.500     |P=0.714N     P=0.500N     P=0.524N     P=0.563N     |
|POLY 3             |     P=0.698N     P=0.109      (e)          P=0.490     |P=0.663N     P=0.507N     P=0.512N     P=0.528N     |
|POLY 1.5           |     P=0.689N     P=0.112      (e)          P=0.494     |P=0.661N     P=0.504N     P=0.509N     P=0.517N     |
|POLY 6             |     P=0.705N     P=0.109      (e)          P=0.487     |P=0.666N     P=0.510N     P=0.515N     P=0.541N     |
|LOGISTIC REGRESSION|     P=0.675N     P=0.124      (e)          P=0.500     |P=0.689N     P=0.507N     P=0.512N     P=0.537N     |
|COCH-ARM / FISHERS |     P=0.672N     P=0.121      (e)          P=0.500     |P=0.660N     P=0.500N     P=0.500N     P=0.500N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 14
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Pancreas                                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/49 (4%)    1/49 (2%)    1/50 (2%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/49 (0%)    |
|POLY-3 ADJUSTED (b)|     5.5%         2.9%         2.7%         2.9%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     1/13 (8%)    0/13 (0%)    1/15 (7%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     720          712          733 (T)      732         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.584N     P=0.538N     P=0.460N     P=0.507N    |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.582N     P=0.520N     P=0.487N     P=0.513N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.575N     P=0.513N     P=0.490N     P=0.505N    |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.590N     P=0.526N     P=0.481N     P=0.521N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.589N     P=0.528N     P=0.472N     P=0.512N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.568N     P=0.500N     P=0.492N     P=0.492N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     21/49 (43%)  22/49 (45%)  21/50 (42%)  19/50 (38%) |42/50 (84%)  43/50 (86%)  36/50 (72%)  31/49 (63%)  |
|POLY-3 ADJUSTED (b)|     49.6%        56.8%        50.9%        48.8%       |92.3%        94.8%        81.3%        74.8%        |
|TERMINAL (d)       |     4/13 (31%)   7/13 (54%)   7/15 (47%)   7/13 (54%)  |19/19 (100%) 17/17 (100%) 19/21 (91%)  9/11 (82%)   |
|FIRST INCIDENCE    |     338          574          513          539         |581          478          339          506          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.439N     P=0.418      P=0.459N     P=0.504N    |P=0.451      P=0.339      P=0.208N     P=0.479      |
|POLY 3             |     P=0.414N     P=0.328      P=0.539      P=0.564N    |P=0.004N**   P=0.470      P=0.081N     P=0.014N*    |
|POLY 1.5           |     P=0.365N     P=0.383      P=0.567      P=0.494N    |P=0.005N**   P=0.497      P=0.094N     P=0.015N*    |
|POLY 6             |     P=0.478N     P=0.283      P=0.510      P=0.555     |P=0.002N**   P=0.437      P=0.068N     P=0.013N*    |
|LOGISTIC REGRESSION|     P=0.344N     P=0.464      P=0.541N     P=0.407N    |P=0.028N*    P=0.238      P=0.204N     P=0.068N     |
|COCH-ARM / FISHERS |     P=0.305N     P=0.500      P=0.547N     P=0.387N    |P=0.007N**   P=0.500      P=0.114N     P=0.017N*    |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 15
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Prostate                                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/48 (4%)    0/50 (0%)    0/50 (0%)   |                                                    |
|POLY-3 ADJUSTED (b)|     0.0%         5.9%         0.0%         0.0%        |                                                    |
|TERMINAL (d)       |     0/13 (0%)    2/13 (15%)   0/15 (0%)    0/13 (0%)   |                                                    |
|FIRST INCIDENCE    |     ---          733 (T)      ---          ---         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.451N     P=0.235      (e)          (e)         |                                                    |
|POLY 3             |     P=0.459N     P=0.220      (e)          (e)         |                                                    |
|POLY 1.5           |     P=0.451N     P=0.223      (e)          (e)         |                                                    |
|POLY 6             |     P=0.468N     P=0.215      (e)          (e)         |                                                    |
|LOGISTIC REGRESSION|     (e)          P=0.235      (e)          (e)         |                                                    |
|COCH-ARM / FISHERS |     P=0.439N     P=0.237      (e)          (e)         |                                                    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Adenoma, Basosquamous Tumor Benign, or                                                                           |
|     Trichoepithelioma                                                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    0/50 (0%)    0/50 (0%)    2/50 (4%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     2.7%         0.0%         0.0%         5.7%        |0.0%         0.0%         0.0%         2.9%         |
|TERMINAL (d)       |     1/13 (8%)    0/13 (0%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    1/11 (9%)    |
|FIRST INCIDENCE    |     733 (T)      ---          ---          702         |---          ---          ---          734 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.158      P=0.500N     P=0.471N     P=0.513     |P=0.159      (e)          (e)          P=0.391      |
|POLY 3             |     P=0.156      P=0.514N     P=0.495N     P=0.483     |P=0.239      (e)          (e)          P=0.473      |
|POLY 1.5           |     P=0.158      P=0.510N     P=0.498N     P=0.489     |P=0.245      (e)          (e)          P=0.483      |
|POLY 6             |     P=0.154      P=0.518N     P=0.491N     P=0.479     |P=0.231      (e)          (e)          P=0.461      |
|LOGISTIC REGRESSION|     P=0.147      (e)          (e)          P=0.483     |(e)          (e)          (e)          P=0.391      |
|COCH-ARM / FISHERS |     P=0.160      P=0.500N     P=0.500N     P=0.500     |P=0.257      (e)          (e)          P=0.500      |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 16
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Carcinoma, Basal Cell Adenoma, Basosquamous                                                                      |
|     Tumor (benign, malignant or NOS), or Trichoepithelioma                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    0/50 (0%)    0/50 (0%)    2/50 (4%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     2.7%         0.0%         0.0%         5.7%        |0.0%         0.0%         2.7%         2.9%         |
|TERMINAL (d)       |     1/13 (8%)    0/13 (0%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    1/11 (9%)    |
|FIRST INCIDENCE    |     733 (T)      ---          ---          702         |---          ---          734 (T)      734 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.158      P=0.500N     P=0.471N     P=0.513     |P=0.302      (e)          P=0.520      P=0.391      |
|POLY 3             |     P=0.156      P=0.514N     P=0.495N     P=0.483     |P=0.399      (e)          P=0.488      P=0.473      |
|POLY 1.5           |     P=0.158      P=0.510N     P=0.498N     P=0.489     |P=0.412      (e)          P=0.491      P=0.483      |
|POLY 6             |     P=0.154      P=0.518N     P=0.491N     P=0.479     |P=0.384      (e)          P=0.487      P=0.461      |
|LOGISTIC REGRESSION|     P=0.147      (e)          (e)          P=0.483     |(e)          (e)          P=0.520      P=0.391      |
|COCH-ARM / FISHERS |     P=0.160      P=0.500N     P=0.500N     P=0.500     |P=0.436      (e)          P=0.500      P=0.500      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal or Sq. Cell Carcinoma, Carcinoma, Basosq. Tumor                                                                       |
|     (M or B), Basal Cell Adenoma, Adenoma, Papilloma, Sq Papilloma, Keratoacanthoma, Trichoepitheliom                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     4/50 (8%)    4/50 (8%)    5/50 (10%)   6/50 (12%)  |0/50 (0%)    0/50 (0%)    2/50 (4%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     10.9%        11.4%        13.3%        16.5%       |0.0%         0.0%         5.4%         2.9%         |
|TERMINAL (d)       |     3/13 (23%)   2/13 (15%)   3/15 (20%)   2/13 (15%)  |0/19 (0%)    0/17 (0%)    2/21 (10%)   1/11 (9%)    |
|FIRST INCIDENCE    |     671          594          702          519         |---          ---          734 (T)      734 (T)      |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.295      P=0.617      P=0.582      P=0.354     |P=0.393      (e)          P=0.259      P=0.391      |
|POLY 3             |     P=0.317      P=0.616      P=0.514      P=0.358     |P=0.498      (e)          P=0.224      P=0.473      |
|POLY 1.5           |     P=0.318      P=0.622      P=0.507      P=0.360     |P=0.514      (e)          P=0.227      P=0.483      |
|POLY 6             |     P=0.321      P=0.619      P=0.527      P=0.364     |P=0.478      (e)          P=0.221      P=0.461      |
|LOGISTIC REGRESSION|     P=0.284      P=0.596      P=0.550      P=0.334     |(e)          (e)          P=0.259      P=0.391      |
|COCH-ARM / FISHERS |     P=0.319      P=0.643N     P=0.500      P=0.370     |P=0.546      (e)          P=0.247      P=0.500      |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 17
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    1/50 (2%)    2/50 (4%)    1/50 (2%)   |1/50 (2%)    0/50 (0%)    2/50 (4%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     8.0%         2.9%         5.3%         2.8%        |2.5%         0.0%         5.3%         2.9%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    1/15 (7%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     566          733 (T)      674          618         |607          ---          684          709          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.420N     P=0.337N     P=0.474N     P=0.336N    |P=0.587      P=0.516N     P=0.484      P=0.698      |
|POLY 3             |     P=0.404N     P=0.340N     P=0.499N     P=0.328N    |P=0.624      P=0.508N     P=0.477      P=0.728      |
|POLY 1.5           |     P=0.400N     P=0.328N     P=0.500N     P=0.319N    |P=0.639      P=0.504N     P=0.484      P=0.741      |
|POLY 6             |     P=0.408N     P=0.354N     P=0.497N     P=0.338N    |P=0.605      P=0.512N     P=0.473      P=0.712      |
|LOGISTIC REGRESSION|     P=0.405N     P=0.316N     P=0.499N     P=0.291N    |P=0.642      P=0.496N     P=0.489      P=0.757      |
|COCH-ARM / FISHERS |     P=0.398N     P=0.309N     P=0.500N     P=0.309N    |P=0.668      P=0.500N     P=0.500      P=0.753N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma,                                                                        |
|     or Fibrous Histiocytoma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    2/50 (4%)    4/50 (8%)    1/50 (2%)   |1/50 (2%)    0/50 (0%)    3/50 (6%)    1/50 (2%)    |
|POLY-3 ADJUSTED (b)|     8.0%         5.8%         10.6%        2.8%        |2.5%         0.0%         8.0%         2.9%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    3/15 (20%)   0/13 (0%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     566          548          674          618         |607          ---          647          709          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.264N     P=0.530N     P=0.544      P=0.336N    |P=0.643      P=0.516N     P=0.286      P=0.698      |
|POLY 3             |     P=0.253N     P=0.538N     P=0.501      P=0.328N    |P=0.672      P=0.508N     P=0.284      P=0.728      |
|POLY 1.5           |     P=0.247N     P=0.526N     P=0.500      P=0.319N    |P=0.683N     P=0.504N     P=0.290      P=0.741      |
|POLY 6             |     P=0.259N     P=0.551N     P=0.503      P=0.338N    |P=0.651      P=0.512N     P=0.282      P=0.712      |
|LOGISTIC REGRESSION|     P=0.249N     P=0.493N     P=0.514      P=0.291N    |P=0.682N     P=0.496N     P=0.297      P=0.757      |
|COCH-ARM / FISHERS |     P=0.242N     P=0.500N     P=0.500      P=0.309N    |P=0.652N     P=0.500N     P=0.309      P=0.753N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 18
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    1/50 (2%)    2/50 (4%)    0/50 (0%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.9%         5.3%         0.0%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    2/15 (13%)   0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          548          733 (T)      ---         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.420N     P=0.495      P=0.268      (e)         |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.417N     P=0.489      P=0.241      (e)         |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.412N     P=0.492      P=0.239      (e)         |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.422N     P=0.488      P=0.245      (e)         |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.412N     P=0.561      P=0.268      (e)         |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.405N     P=0.500      P=0.247      (e)         |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma, Sarcoma, Myxosarcoma, or Fibrous Histiocytoma                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    1/50 (2%)    2/50 (4%)    0/50 (0%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         2.9%         5.3%         0.0%        |0.0%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    2/15 (13%)   0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          548          733 (T)      ---         |---          ---          647          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.420N     P=0.495      P=0.268      (e)         |P=0.771N     (e)          P=0.477      (e)          |
|POLY 3             |     P=0.417N     P=0.489      P=0.241      (e)         |P=0.761N     (e)          P=0.490      (e)          |
|POLY 1.5           |     P=0.412N     P=0.492      P=0.239      (e)         |P=0.754N     (e)          P=0.492      (e)          |
|POLY 6             |     P=0.422N     P=0.488      P=0.245      (e)         |P=0.769N     (e)          P=0.490      (e)          |
|LOGISTIC REGRESSION|     P=0.412N     P=0.561      P=0.268      (e)         |P=0.744N     (e)          P=0.503      (e)          |
|COCH-ARM / FISHERS |     P=0.405N     P=0.500      P=0.247      (e)         |P=0.743N     (e)          P=0.500      (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 19
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Keratoacanthoma                                                                                                             |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    2/50 (4%)    4/50 (8%)    3/50 (6%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     8.1%         5.8%         10.6%        8.4%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     2/13 (15%)   1/13 (8%)    2/15 (13%)   1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     671          621          702          519         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.580      P=0.527N     P=0.568      P=0.642     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.603      P=0.531N     P=0.512      P=0.652     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.602      P=0.522N     P=0.506      P=0.654     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.606      P=0.537N     P=0.523      P=0.654     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.578      P=0.541N     P=0.542      P=0.646     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.601      P=0.500N     P=0.500      P=0.661N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    2/50 (4%)    1/50 (2%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         5.8%         2.7%         2.8%        |0.0%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    1/15 (7%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          594          733 (T)      621         |---          ---          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.693      P=0.228      P=0.529      P=0.475     |P=0.841N     (e)          P=0.520      (e)          |
|POLY 3             |     P=0.690      P=0.223      P=0.505      P=0.492     |P=0.761N     (e)          P=0.488      (e)          |
|POLY 1.5           |     P=0.694      P=0.227      P=0.502      P=0.495     |P=0.754N     (e)          P=0.491      (e)          |
|POLY 6             |     P=0.688      P=0.221      P=0.509      P=0.491     |P=0.769N     (e)          P=0.487      (e)          |
|LOGISTIC REGRESSION|     P=0.696      P=0.226      P=0.529      P=0.509     |(e)          (e)          P=0.520      (e)          |
|COCH-ARM / FISHERS |     P=0.702      P=0.247      P=0.500      P=0.500     |P=0.743N     (e)          P=0.500      (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 20
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, Squamous Cell                                                                           |
|     Carcinoma or Keratoacanthoma                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    4/50 (8%)    5/50 (10%)   4/50 (8%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     8.1%         11.4%        13.3%        11.0%       |0.0%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     2/13 (15%)   2/13 (15%)   3/15 (20%)   1/13 (8%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     671          594          702          519         |---          ---          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.561      P=0.468      P=0.428      P=0.471     |P=0.841N     (e)          P=0.520      (e)          |
|POLY 3             |     P=0.587      P=0.471      P=0.366      P=0.491     |P=0.761N     (e)          P=0.488      (e)          |
|POLY 1.5           |     P=0.586      P=0.477      P=0.361      P=0.492     |P=0.754N     (e)          P=0.491      (e)          |
|POLY 6             |     P=0.594      P=0.470      P=0.374      P=0.497     |P=0.769N     (e)          P=0.487      (e)          |
|LOGISTIC REGRESSION|     P=0.561      P=0.454      P=0.393      P=0.484     |(e)          (e)          P=0.520      (e)          |
|COCH-ARM / FISHERS |     P=0.586      P=0.500      P=0.357      P=0.500     |P=0.743N     (e)          P=0.500      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, or Keratoacanthoma                                                                      |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/50 (6%)    4/50 (8%)    5/50 (10%)   4/50 (8%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     8.1%         11.4%        13.3%        11.0%       |0.0%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     2/13 (15%)   2/13 (15%)   3/15 (20%)   1/13 (8%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     671          594          702          519         |---          ---          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.561      P=0.468      P=0.428      P=0.471     |P=0.841N     (e)          P=0.520      (e)          |
|POLY 3             |     P=0.587      P=0.471      P=0.366      P=0.491     |P=0.761N     (e)          P=0.488      (e)          |
|POLY 1.5           |     P=0.586      P=0.477      P=0.361      P=0.492     |P=0.754N     (e)          P=0.491      (e)          |
|POLY 6             |     P=0.594      P=0.470      P=0.374      P=0.497     |P=0.769N     (e)          P=0.487      (e)          |
|LOGISTIC REGRESSION|     P=0.561      P=0.454      P=0.393      P=0.484     |(e)          (e)          P=0.520      (e)          |
|COCH-ARM / FISHERS |     P=0.586      P=0.500      P=0.357      P=0.500     |P=0.743N     (e)          P=0.500      (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 21
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Testes                                                                                                                           |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     45/50 (90%)  40/50 (80%)  46/50 (92%)  41/50 (82%) |                                                    |
|POLY-3 ADJUSTED (b)|     95.5%        90.1%        95.5%        90.9%       |                                                    |
|TERMINAL (d)       |     13/13 (100%) 12/13 (92%)  15/15 (100%) 13/13 (100%)|                                                    |
|FIRST INCIDENCE    |     506          524          394          422         |                                                    |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.516N     P=0.443N     P=0.409N     P=0.465N    |                                                    |
|POLY 3             |     P=0.345N     P=0.227N     P=0.742N     P=0.269N    |                                                    |
|POLY 1.5           |     P=0.284N     P=0.199N     P=0.643      P=0.228N    |                                                    |
|POLY 6             |     P=0.473N     P=0.237N     P=0.841N     P=0.357N    |                                                    |
|LOGISTIC REGRESSION|     P=0.321N     P=0.314N     P=0.511      P=0.337N    |                                                    |
|COCH-ARM / FISHERS |     P=0.267N     P=0.131N     P=0.500      P=0.194N    |                                                    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/46 (7%)    5/46 (11%)   6/49 (12%)   2/50 (4%)   |7/50 (14%)   4/49 (8%)    4/48 (8%)    1/49 (2%)    |
|POLY-3 ADJUSTED (b)|     8.7%         14.6%        15.5%        5.7%        |17.5%        10.5%        10.8%        2.9%         |
|TERMINAL (d)       |     1/13 (8%)    1/13 (8%)    2/15 (13%)   0/13 (0%)   |3/19 (16%)   2/17 (12%)   2/21 (10%)   0/11 (0%)    |
|FIRST INCIDENCE    |     645          393          562          645         |677          700          630          703          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.227N     P=0.334      P=0.290      P=0.523N    |P=0.137N     P=0.300N     P=0.271N     P=0.101N     |
|POLY 3             |     P=0.202N     P=0.350      P=0.299      P=0.489N    |P=0.078N     P=0.286N     P=0.306N     P=0.048N*    |
|POLY 1.5           |     P=0.189N     P=0.351      P=0.287      P=0.478N    |P=0.069N     P=0.280N     P=0.302N     P=0.042N*    |
|POLY 6             |     P=0.217N     P=0.350      P=0.318      P=0.501N    |P=0.091N     P=0.293N     P=0.306N     P=0.058N     |
|LOGISTIC REGRESSION|     P=0.179N     P=0.347      P=0.278      P=0.502N    |P=0.086N     P=0.283N     P=0.312N     P=0.062N     |
|COCH-ARM / FISHERS |     P=0.172N     P=0.357      P=0.276      P=0.460N    |P=0.057N     P=0.274N     P=0.286N     P=0.032N*    |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 22
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/46 (0%)    3/46 (7%)    2/49 (4%)    1/50 (2%)   |2/50 (4%)    1/49 (2%)    2/48 (4%)    3/49 (6%)    |
|POLY-3 ADJUSTED (b)|     0.0%         9.0%         5.4%         2.8%        |5.0%         2.6%         5.5%         8.7%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    0/13 (0%)   |1/19 (5%)    1/17 (6%)    1/21 (5%)    1/11 (9%)    |
|FIRST INCIDENCE    |     ---          614          660          615         |684          734 (T)      605          632          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.530N     P=0.110      P=0.258      P=0.482     |P=0.179      P=0.518N     P=0.692      P=0.353      |
|POLY 3             |     P=0.503N     P=0.112      P=0.257      P=0.507     |P=0.275      P=0.516N     P=0.667      P=0.436      |
|POLY 1.5           |     P=0.493N     P=0.114      P=0.254      P=0.510     |P=0.291      P=0.512N     P=0.669      P=0.455      |
|POLY 6             |     P=0.513N     P=0.111      P=0.261      P=0.503     |P=0.258      P=0.520N     P=0.667      P=0.415      |
|LOGISTIC REGRESSION|     P=0.498N     P=0.112      P=0.257      P=0.529     |P=0.260      P=0.515N     P=0.667      P=0.417      |
|COCH-ARM / FISHERS |     P=0.477N     P=0.121      P=0.263      P=0.521     |P=0.320      P=0.508N     P=0.676      P=0.490      |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     3/46 (7%)    8/46 (17%)   8/49 (16%)   3/50 (6%)   |9/50 (18%)   5/49 (10%)   6/48 (13%)   4/49 (8%)    |
|POLY-3 ADJUSTED (b)|     8.7%         23.0%        20.5%        8.4%        |22.4%        13.1%        16.1%        11.6%        |
|TERMINAL (d)       |     1/13 (8%)    2/13 (15%)   2/15 (13%)   0/13 (0%)   |4/19 (21%)   3/17 (18%)   3/21 (14%)   1/11 (9%)    |
|FIRST INCIDENCE    |     645          393          562          615         |677          700          605          632          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.201N     P=0.093      P=0.139      P=0.633     |P=0.456N     P=0.232N     P=0.299N     P=0.316N     |
|POLY 3             |     P=0.161N     P=0.093      P=0.136      P=0.649N    |P=0.277N     P=0.218N     P=0.338N     P=0.176N     |
|POLY 1.5           |     P=0.151N     P=0.094      P=0.128      P=0.639N    |P=0.252N     P=0.211N     P=0.335N     P=0.156N     |
|POLY 6             |     P=0.173N     P=0.092      P=0.151      P=0.658N    |P=0.308N     P=0.226N     P=0.336N     P=0.202N     |
|LOGISTIC REGRESSION|     P=0.148N     P=0.091      P=0.124      P=0.656N    |P=0.309N     P=0.211N     P=0.351N     P=0.210N     |
|COCH-ARM / FISHERS |     P=0.137N     P=0.099      P=0.120      P=0.621N    |P=0.211N     P=0.205N     P=0.318N     P=0.125N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 23
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/46 (2%)    0/46 (0%)    0/49 (0%)    0/50 (0%)   |2/50 (4%)    0/49 (0%)    0/48 (0%)    1/49 (2%)    |
|POLY-3 ADJUSTED (b)|     2.9%         0.0%         0.0%         0.0%        |5.0%         0.0%         0.0%         2.9%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |1/19 (5%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     688          ---          ---          ---         |660          ---          ---          631          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.662N     P=0.490N     P=0.471N     P=0.490N    |P=0.596      P=0.262N     P=0.242N     P=0.597N     |
|POLY 3             |     P=0.653N     P=0.508N     P=0.484N     P=0.497N    |P=0.630      P=0.247N     P=0.257N     P=0.551N     |
|POLY 1.5           |     P=0.650N     P=0.505N     P=0.486N     P=0.491N    |P=0.637      P=0.245N     P=0.254N     P=0.535N     |
|POLY 6             |     P=0.656N     P=0.513N     P=0.483N     P=0.504N    |P=0.621      P=0.250N     P=0.260N     P=0.569N     |
|LOGISTIC REGRESSION|     P=0.662N     P=0.509N     P=0.482N     P=0.500N    |P=0.636      P=0.247N     P=0.256N     P=0.538N     |
|COCH-ARM / FISHERS |     P=0.647N     P=0.500N     P=0.484N     P=0.479N    |P=0.652      P=0.253N     P=0.258N     P=0.508N     |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                        |                                                    |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/46 (2%)    0/46 (0%)    0/49 (0%)    0/50 (0%)   |2/50 (4%)    1/49 (2%)    1/48 (2%)    2/49 (4%)    |
|POLY-3 ADJUSTED (b)|     2.9%         0.0%         0.0%         0.0%        |5.0%         2.6%         2.8%         5.8%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |1/19 (5%)    1/17 (6%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     688          ---          ---          ---         |660          734 (T)      734 (T)      631          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.662N     P=0.490N     P=0.471N     P=0.490N    |P=0.372      P=0.536N     P=0.491N     P=0.600      |
|POLY 3             |     P=0.653N     P=0.508N     P=0.484N     P=0.497N    |P=0.461      P=0.517N     P=0.532N     P=0.643      |
|POLY 1.5           |     P=0.650N     P=0.505N     P=0.486N     P=0.491N    |P=0.475      P=0.512N     P=0.527N     P=0.658      |
|POLY 6             |     P=0.656N     P=0.513N     P=0.483N     P=0.504N    |P=0.446      P=0.522N     P=0.537N     P=0.626      |
|LOGISTIC REGRESSION|     P=0.662N     P=0.509N     P=0.482N     P=0.500N    |P=0.443      P=0.516N     P=0.531N     P=0.654      |
|COCH-ARM / FISHERS |     P=0.647N     P=0.500N     P=0.484N     P=0.479N    |P=0.501      P=0.508N     P=0.515N     P=0.684      |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 24
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Tongue                                                                                                                           |
|     Squamous Cell Carcinoma or Papilloma Squamous                                                                               |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    0/50 (0%)    1/50 (2%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     5.3%         0.0%         2.7%         2.9%        |0.0%         0.0%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    1/21 (5%)    0/11 (0%)    |
|FIRST INCIDENCE    |     506          ---          702          702         |---          ---          734 (T)      ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.698N     P=0.275N     P=0.482N     P=0.510N    |P=0.841N     (e)          P=0.520      (e)          |
|POLY 3             |     P=0.704N     P=0.258N     P=0.499N     P=0.525N    |P=0.761N     (e)          P=0.488      (e)          |
|POLY 1.5           |     P=0.702N     P=0.251N     P=0.500N     P=0.515N    |P=0.754N     (e)          P=0.491      (e)          |
|POLY 6             |     P=0.708N     P=0.266N     P=0.497N     P=0.536N    |P=0.769N     (e)          P=0.487      (e)          |
|LOGISTIC REGRESSION|     P=0.702N     P=0.196N     P=0.507N     P=0.486N    |(e)          (e)          P=0.520      (e)          |
|COCH-ARM / FISHERS |     P=0.702N     P=0.247N     P=0.500N     P=0.500N    |P=0.743N     (e)          P=0.500      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Polyp Stromal                                                                                                               |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |                                                        |7/50 (14%)   6/50 (12%)   6/50 (12%)   2/50 (4%)    |
|POLY-3 ADJUSTED (b)|                                                        |17.4%        15.1%        15.6%        5.7%         |
|TERMINAL (d)       |                                                        |3/19 (16%)   1/17 (6%)    3/21 (14%)   1/11 (9%)    |
|FIRST INCIDENCE    |                                                        |589          585          534          422          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |                                                        |P=0.164N     P=0.533N     P=0.494N     P=0.210N     |
|POLY 3             |                                                        |P=0.098N     P=0.512N     P=0.536N     P=0.111N     |
|POLY 1.5           |                                                        |P=0.085N     P=0.507N     P=0.528N     P=0.098N     |
|POLY 6             |                                                        |P=0.121N     P=0.510N     P=0.538N     P=0.131N     |
|LOGISTIC REGRESSION|                                                        |P=0.080N     P=0.517N     P=0.537N     P=0.100N     |
|COCH-ARM / FISHERS |                                                        |P=0.067N     P=0.500N     P=0.500N     P=0.080N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 25
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Hemangioma                                                                                                                  |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    0/50 (0%)    2/50 (4%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         0.0%         5.7%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          ---          ---          668         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.042 *    (e)          (e)          P=0.224     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.043 *    (e)          (e)          P=0.227     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.044 *    (e)          (e)          P=0.230     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.043 *    (e)          (e)          P=0.225     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.041 *    (e)          (e)          P=0.223     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.046 *    (e)          (e)          P=0.247     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Hemangiosarcoma or Hemangioma                                                                                               |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    1/50 (2%)    2/50 (4%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         2.7%         5.7%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          ---          678          668         |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.119      (e)          P=0.508      P=0.224     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.126      (e)          P=0.506      P=0.227     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.127      (e)          P=0.503      P=0.230     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.126      (e)          P=0.511      P=0.225     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.118      (e)          P=0.505      P=0.223     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.128      (e)          P=0.500      P=0.247     |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 26
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Histiocytic Sarcoma                                                                                                         |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)   |0/50 (0%)    2/50 (4%)    1/50 (2%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     0.0%         0.0%         2.6%         0.0%        |0.0%         5.1%         2.7%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    0/13 (0%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     ---          ---          443          ---         |---          559          678          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.746N     (e)          P=0.500      (e)         |P=0.396N     P=0.223      P=0.465      (e)          |
|POLY 3             |     P=0.745N     (e)          P=0.509      (e)         |P=0.390N     P=0.236      P=0.489      (e)          |
|POLY 1.5           |     P=0.743N     (e)          P=0.505      (e)         |P=0.377N     P=0.237      P=0.492      (e)          |
|POLY 6             |     P=0.746N     (e)          P=0.515      (e)         |P=0.405N     P=0.237      P=0.489      (e)          |
|LOGISTIC REGRESSION|     P=0.769N     (e)          P=0.454      (e)         |P=0.327N     P=0.236      P=0.493      (e)          |
|COCH-ARM / FISHERS |     P=0.743N     (e)          P=0.500      (e)         |P=0.358N     P=0.247      P=0.500      (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Leukemia: Lymphocytic, Monocytic, Mononuclear, or                                                                           |
|     Undifferentiated                                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     19/50 (38%)  28/50 (56%)  33/50 (66%)  28/50 (56%) |22/50 (44%)  21/50 (42%)  18/50 (36%)  33/50 (66%)  |
|POLY-3 ADJUSTED (b)|     45.6%        65.9%        73.1%        66.4%       |51.7%        48.2%        42.2%        73.7%        |
|TERMINAL (d)       |     4/13 (31%)   7/13 (54%)   12/15 (80%)  7/13 (54%)  |11/19 (58%)  5/17 (29%)   5/21 (24%)   6/11 (55%)   |
|FIRST INCIDENCE    |     506          350          450          520         |506          497          310          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.309      P=0.070      P=0.047 *    P=0.077     |P<0.001 **   P=0.540      P=0.317N     P=0.003 **   |
|POLY 3             |     P=0.288      P=0.038 *    P=0.004 **   P=0.034 *   |P<0.001 **   P=0.456N     P=0.248N     P=0.021 *    |
|POLY 1.5           |     P=0.306      P=0.040 *    P=0.004 **   P=0.039 *   |P<0.001 **   P=0.475N     P=0.263N     P=0.017 *    |
|POLY 6             |     P=0.294      P=0.039 *    P=0.006 **   P=0.036 *   |P=0.002 **   P=0.417N     P=0.221N     P=0.033 *    |
|LOGISTIC REGRESSION|     P=0.327      P=0.047 *    P=0.005 **   P=0.043 *   |P=0.002 **   P=0.520N     P=0.290N     P=0.012 *    |
|COCH-ARM / FISHERS |     P=0.347      P=0.054      P=0.004 **   P=0.054     |P=0.002 **   P=0.500N     P=0.270N     P=0.022 *    |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 27
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Mesothelioma: Benign, Malignant, NOS                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     2/50 (4%)    2/50 (4%)    1/50 (2%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     5.3%         5.8%         2.7%         2.9%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    1/13 (8%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     599          534          680          733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.489N     P=0.659      P=0.484N     P=0.523N    |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.485N     P=0.668      P=0.497N     P=0.525N    |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.475N     P=0.676      P=0.499N     P=0.515N    |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.498N     P=0.661      P=0.495N     P=0.538N    |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.466N     P=0.686N     P=0.503N     P=0.509N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.463N     P=0.691N     P=0.500N     P=0.500N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Osteosarcoma                                                                                                                |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    0/50 (0%)    2/50 (4%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     2.7%         0.0%         5.2%         2.9%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     567          ---          562          733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.643      P=0.510N     P=0.512      P=0.752     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.666      P=0.517N     P=0.511      P=0.747     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.668      P=0.512N     P=0.506      P=0.752     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.663      P=0.523N     P=0.521      P=0.742     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.671      P=0.454N     P=0.489      P=0.761     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.668      P=0.500N     P=0.500      P=0.753N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 28
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Osteosarcoma or Osteoma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     1/50 (2%)    0/50 (0%)    2/50 (4%)    1/50 (2%)   |0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)    |
|POLY-3 ADJUSTED (b)|     2.7%         0.0%         5.2%         2.9%        |0.0%         0.0%         0.0%         0.0%         |
|TERMINAL (d)       |     0/13 (0%)    0/13 (0%)    0/15 (0%)    1/13 (8%)   |0/19 (0%)    0/17 (0%)    0/21 (0%)    0/11 (0%)    |
|FIRST INCIDENCE    |     567          ---          562          733 (T)     |---          ---          ---          ---          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.643      P=0.510N     P=0.512      P=0.752     |(e)          (e)          (e)          (e)          |
|POLY 3             |     P=0.666      P=0.517N     P=0.511      P=0.747     |(e)          (e)          (e)          (e)          |
|POLY 1.5           |     P=0.668      P=0.512N     P=0.506      P=0.752     |(e)          (e)          (e)          (e)          |
|POLY 6             |     P=0.663      P=0.523N     P=0.521      P=0.742     |(e)          (e)          (e)          (e)          |
|LOGISTIC REGRESSION|     P=0.671      P=0.454N     P=0.489      P=0.761     |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.668      P=0.500N     P=0.500      P=0.753N    |(e)          (e)          (e)          (e)          |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Benign Tumors                                                                                                               |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     50/50 (100%) 47/50 (94%)  49/50 (98%)  46/50 (92%) |48/50 (96%)  46/50 (92%)  43/50 (86%)  43/50 (86%)  |
|POLY-3 ADJUSTED (b)|     100.0%       99.6%        99.1%        96.8%       |99.7%        97.7%        93.9%        94.2%        |
|TERMINAL (d)       |     13/13 (100%) 13/13 (100%) 15/15 (100%) 13/13 (100%)|19/19 (100%) 17/17 (100%) 21/21 (100%) 10/11 (91%)  |
|FIRST INCIDENCE    |     338          393          394          422         |497          422          339          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.518N     P=0.531      P=0.319N     P=0.488N    |P=0.064      P=0.493      P=0.288N     P=0.136      |
|POLY 3             |     P=0.116N     P=1.000N     P=0.891N     P=0.276N    |P=0.205N     P=0.533N     P=0.104N     P=0.123N     |
|POLY 1.5           |     P=0.073N     P=0.700N     P=0.689N     P=0.141N    |P=0.193N     P=0.331N     P=0.074N     P=0.084N     |
|POLY 6             |     P=0.258N     P=1.000N     P=1.000N     P=0.498N    |P=0.215N     P=1.000N     P=0.179N     P=0.211N     |
|LOGISTIC REGRESSION|     P=0.066N     P=0.395N     P=0.489N     P=0.089N    |P=0.459N     P=0.331N     P=0.164N     P=0.247N     |
|COCH-ARM / FISHERS |     P=0.104N     P=0.121N     P=0.500N     P=0.059N    |P=0.164N     P=0.339N     P=0.080N     P=0.080N     |
|=================================================================================================================================|
       Date:  02/17/99                           EXPERIMENT: 05180 TEST: 06                                            Page 29
                     Statistical Analysis of Primary Tumors in Rats(FISCHER 344)       -                  GALLIUM ARSENIDE
                                         Terminal Sacrifice at 105 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Tumors                                                                                                            |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     30/50 (60%)  38/50 (76%)  41/50 (82%)  34/50 (68%) |28/50 (56%)  28/50 (56%)  32/50 (64%)  38/50 (76%)  |
|POLY-3 ADJUSTED (b)|     67.2%        81.8%        85.9%        77.8%       |63.9%        61.5%        72.4%        82.6%        |
|TERMINAL (d)       |     8/13 (62%)   10/13 (77%)  12/15 (80%)  9/13 (69%)  |13/19 (68%)  8/17 (47%)   15/21 (71%)  7/11 (64%)   |
|FIRST INCIDENCE    |     506          204          443          520         |506          478          310          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.534N     P=0.109      P=0.171      P=0.261     |P<0.001 **   P=0.452      P=0.315      P=0.004 **   |
|POLY 3             |     P=0.567      P=0.070      P=0.020 *    P=0.171     |P=0.014 *    P=0.495N     P=0.251      P=0.028 *    |
|POLY 1.5           |     P=0.521N     P=0.065      P=0.015 *    P=0.200     |P=0.011 *    P=0.530N     P=0.250      P=0.021 *    |
|POLY 6             |     P=0.516      P=0.078      P=0.032 *    P=0.159     |P=0.023 *    P=0.443N     P=0.269      P=0.051      |
|LOGISTIC REGRESSION|     P=0.401N     P=0.070      P=0.014 *    P=0.220     |P=0.010 *    P=0.565      P=0.204      P=0.012 *    |
|COCH-ARM / FISHERS |     P=0.389N     P=0.066      P=0.013 *    P=0.266     |P=0.017 *    P=0.580N     P=0.270      P=0.028 *    |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                              Males                     |                       Females                      |
|Dose               |     CONTROL      0.01         0.1          1.0         |CONTROL      0.01         0.1          1.0          |
|                   |                  MG/M3        MG/M3        MG/M3       |             MG/M3        MG/M3        MG/M3        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant and Benign Tumors                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |     #            #            #            #           |#            #            #            #            |
|-----------        |                                                        |                                                    |
|OVERALL (a)        |     50/50 (100%) 49/50 (98%)  50/50 (100%) 48/50 (96%) |48/50 (96%)  49/50 (98%)  49/50 (98%)  47/50 (94%)  |
|POLY-3 ADJUSTED (b)|     100.0%       99.9%        100.0%       99.4%       |99.7%        99.8%        100.0%       99.7%        |
|TERMINAL (d)       |     13/13 (100%) 13/13 (100%) 15/15 (100%) 13/13 (100%)|19/19 (100%) 17/17 (100%) 21/21 (100%) 11/11 (100%) |
|FIRST INCIDENCE    |     338          204          394          422         |497          422          310          418          |
|-------------------|                                                        |                                                    |
|STATISTICAL TESTS  |                                                        |                                                    |
|-------------------|                                                        |                                                    |
|LIFE TABLE         |     P=0.495      P=0.436      (e)          P=0.512     |P=0.041 *    P=0.342      P=0.485      P=0.050      |
|POLY 3             |     P=0.999N     P=1.000N     (e)          P=1.000N    |P=1.000N     P=1.000      P=1.000      P=1.000      |
|POLY 1.5           |     P=0.506N     P=0.996N     (e)          P=0.705N    |P=0.809N     P=0.937      P=0.927      P=0.948N     |
|POLY 6             |     P=1.000N     P=1.000N     (e)          P=1.000N    |P=1.000N     P=1.000      P=1.000      P=1.000      |
|LOGISTIC REGRESSION|     P=0.075N     P=0.848N     (e)          P=0.294N    |(e)          (e)          (e)          (e)          |
|COCH-ARM / FISHERS |     P=0.156N     P=0.500N     (e)          P=0.247N    |P=0.255N     P=0.500      P=0.500      P=0.500N     |
|=================================================================================================================================|

(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).