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TDMS Study 05107-05 Pathology Tables

NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: LITRI                                                  NICKEL SUBSULFIDE                                  DATE: 05/19/95       
EXPERIMENT: 05107 TEST: 05                                                                                     TIME: 22:25:53       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: Y01ES30108                                ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: C61654       
PATHOLOGIST: F. HAHN                                                                                           CAS: 12035722        
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               REASONS FOR REMOVAL:    ALL                                                                                          
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       INCLUDE ALL                                                                                  
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: LITRI                                                  NICKEL SUBSULFIDE                                  DATE: 05/19/95       
EXPERIMENT: 05107 TEST: 05                                                                                     TIME: 22:25:53       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: Y01ES30108                                ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: C61654       
PATHOLOGIST: F. HAHN                                                                                           CAS: 12035722        


                                                    RATS(FISCHER344)
                                              ----------------------------
             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 NUMBER OF ANIMALS NECROPSIED.
                                                                    
                                                    ----------------
                                                    Adrenal Cortex
                                                    Adrenal Medulla
                                                    Bone Marrow
                                                    Brain
                                                    Clitoral Gland
                                                    Clitoral/Preputial Gland
                                                    Epididymis
                                                    Heart
                                                    Islets, Pancreatic
                                                    Kidney
                                                    Larynx
                                                    Liver
                                                    Lung
                                                    Nose
                                                    Ovary
                                                    Pancreas
                                                    Parathyroid Gland
                                                    Pituitary Gland
                                                    Preputial Gland
                                                    Prostate
                                                    Salivary Glands
                                                    Spleen
                                                    Testes
                                                    Thymus
                                                    Thyroid Gland
                                                    Urinary Bladder
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: LITRI                                                  NICKEL SUBSULFIDE                                  DATE: 05/19/95       
EXPERIMENT: 05107 TEST: 05                                                                                     TIME: 22:25:53       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: Y01ES30108                                ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: C61654       
PATHOLOGIST: F. HAHN                                                                                           CAS: 12035722        


                                     SUMMARY OF STATISTICALLY SIGNIFICANT (P<=.05) RESULTS
                                       IN THE ANALYSIS OF THE STUDY OF NICKEL SUBSULFIDE
              ====================================================================================================
                                                           MALE RATS
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------
              Adrenal Medulla               Pheochromocytoma Benign
                                            Pheochromocytoma Malignant
                                            Pheochromocytoma: Benign, Complex, Malignant, NOS
              Lung                          Alveolar/Bronchiolar Adenoma
                                            Alveolar/Bronchiolar Carcinoma
                                            Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma
              Skin                          Squamous Cell Papilloma, Papilloma, Squamous Cell Carcinoma or Keratoacanthoma
                                            Squamous Cell Papilloma, Papilloma, or Keratoacanthoma
              Testes                        Adenoma
              Thyroid Gland: C-Cell         Adenoma
              All Organs                    Malignant Tumors
                                            Malignant and Benign Tumors
              ====================================================================================================
                                                           FEMALE RATS
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------
              Adrenal Medulla               Pheochromocytoma Benign
                                            Pheochromocytoma: Benign, Complex, Malignant, NOS
              Lung                          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
              All Organs                    Benign Tumors
              ====================================================================================================
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   1
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Benign                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    13/58 (22%)     30/57 (53%)     37/58 (64%)     |     2/58 (3%)       7/56 (13%)     36/58 (62%)     |
|ADJUSTED (b)           |     54.4%           84.5%           88.0%          |      7.6%           24.4%           85.5%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/3 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     4/13 (31%)     16/21 (76%)     13/18 (72%)     |     1/25 (4%)       5/25 (20%)     22/28 (79%)     |
|FIRST INCIDENCE (DAYS) |      559             455             552           |      721             590             563           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.006 **      P=0.054         P=0.004 **     |     P<0.001 **      P=0.087         P<0.001 **     |
|INCIDENTAL TUMOR       |     P<0.001 **      P<0.001 **      P<0.001 **     |     P<0.001 **      P=0.086         P<0.001 **     |
|LOGISTIC REGRESSION    |     P<0.001 **      P=0.002 **      P<0.001 **     |     P<0.001 **      P=0.082         P<0.001 **     |
|COCHRAN-ARMITAGE       |     P<0.001 **                                     |     P<0.001 **                                     |
|FISHER EXACT           |                     P<0.001 **      P<0.001 **     |                     P=0.073         P<0.001 **     |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Malignant                                                                                                  |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/58 (0%)       2/57 (4%)      11/58 (19%)     |     1/58 (2%)       0/56 (0%)       1/58 (2%)      |
|ADJUSTED (b)           |      0.0%            6.9%           48.6%          |      3.1%            0.0%            3.6%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/3 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       7/18 (39%)     |     0/25 (0%)       0/25 (0%)       1/28 (4%)      |
|FIRST INCIDENCE (DAYS) |      ---             601             703           |      677             ---             729 (T)       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P<0.001 **      P=0.309         P=0.004 **     |     P=0.633         P=0.494N        P=0.748N       |
|INCIDENTAL TUMOR       |     P<0.001 **      P=0.190         P=0.001 **     |     P=0.567         P=0.536N        P=0.701        |
|LOGISTIC REGRESSION    |     P<0.001 **      P=0.250         P=0.002 **     |     P=0.628         P=0.499N        P=0.755N       |
|COCHRAN-ARMITAGE       |     P<0.001 **                                     |     P=0.624                                        |
|FISHER EXACT           |                     P=0.243         P<0.001 **     |                     P=0.509N        P=0.752N       |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   2
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma: Benign, Complex, Malignant, NOS                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    14/58 (24%)     30/57 (53%)     42/58 (72%)     |     3/58 (5%)       7/56 (13%)     36/58 (62%)     |
|ADJUSTED (b)           |     55.4%           84.5%          100.0%          |     10.4%           24.4%           85.5%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/3 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     4/13 (31%)     16/21 (76%)     18/18 (100%)    |     1/25 (4%)       5/25 (20%)     22/28 (79%)     |
|FIRST INCIDENCE (DAYS) |      553             455             552           |      677             590             563           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P<0.001 **      P=0.081         P<0.001 **     |     P<0.001 **      P=0.170         P<0.001 **     |
|INCIDENTAL TUMOR       |     P<0.001 **      P=0.002 **      P<0.001 **     |     P<0.001 **      P=0.159         P<0.001 **     |
|LOGISTIC REGRESSION    |     P<0.001 **      P=0.004 **      P<0.001 **     |     P<0.001 **      P=0.164         P<0.001 **     |
|COCHRAN-ARMITAGE       |     P<0.001 **                                     |     P<0.001 **                                     |
|FISHER EXACT           |                     P=0.001 **      P<0.001 **     |                     P=0.147         P<0.001 **     |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     1/58 (2%)       2/58 (3%)       0/59 (0%)      |     0/57 (0%)       2/57 (4%)       1/57 (2%)      |
|ADJUSTED (b)           |      7.7%            6.4%            0.0%          |      0.0%            6.7%            3.6%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/1 (0%)       |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       0/21 (0%)       0/18 (0%)      |     0/25 (0%)       1/25 (4%)       1/28 (4%)      |
|FIRST INCIDENCE (DAYS) |      733 (T)         599             ---           |      ---             642             729 (T)       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.261N        P=0.636         P=0.435N       |     P=0.657         P=0.234         P=0.523        |
|INCIDENTAL TUMOR       |     P=0.279N        P=0.509         P=0.435N       |     P=0.689         P=0.292         P=0.523        |
|LOGISTIC REGRESSION    |     P=0.271N        P=0.544         P=0.435N       |     P=0.649         P=0.241         P=0.523        |
|COCHRAN-ARMITAGE       |     P=0.283N                                       |     P=0.642                                        |
|FISHER EXACT           |                     P=0.500         P=0.496N       |                     P=0.248         P=0.500        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   3
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     2/58 (3%)       0/58 (0%)       0/59 (0%)      |     2/57 (4%)       3/57 (5%)       3/57 (5%)      |
|ADJUSTED (b)           |      5.5%            0.0%            0.0%          |      4.0%            9.2%           10.1%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/1 (0%)       |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     1/5 (20%)       0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |     0/25 (0%)       1/25 (4%)       2/28 (7%)      |
|FIRST INCIDENCE (DAYS) |      553             ---             ---           |      459 (I)         620             709           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.278N        P=0.221N        P=0.218N       |     P=0.547         P=0.516         P=0.532        |
|INCIDENTAL TUMOR       |     P=0.308N        P=0.214N        P=0.249N       |     P=0.498         P=0.570         P=0.503        |
|LOGISTIC REGRESSION    |     P=0.288N        P=0.255N        P=0.240N       |     P=0.514         P=0.481         P=0.497        |
|COCHRAN-ARMITAGE       |     P=0.287N                                       |     P=0.514                                        |
|FISHER EXACT           |                     P=0.248N        P=0.244N       |                     P=0.500         P=0.500        |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     3/58 (5%)       2/58 (3%)       0/59 (0%)      |     2/57 (4%)       5/57 (9%)       4/57 (7%)      |
|ADJUSTED (b)           |     12.8%            6.4%            0.0%          |      4.0%           15.4%           13.6%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/1 (0%)       |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     1/5 (20%)       0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       0/21 (0%)       0/18 (0%)      |     0/25 (0%)       2/25 (8%)       3/28 (11%)     |
|FIRST INCIDENCE (DAYS) |      553             599             ---           |      459 (I)         620             709           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.096N        P=0.380N        P=0.095N       |     P=0.509         P=0.231         P=0.376        |
|INCIDENTAL TUMOR       |     P=0.112N        P=0.474N        P=0.109N       |     P=0.485         P=0.295         P=0.349        |
|LOGISTIC REGRESSION    |     P=0.105N        P=0.483N        P=0.114N       |     P=0.473         P=0.210         P=0.339        |
|COCHRAN-ARMITAGE       |     P=0.107N                                       |     P=0.469                                        |
|FISHER EXACT           |                     P=0.500N        P=0.119N       |                     P=0.219         P=0.339        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   4
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Heart                                                                                                                            |
|     Schwannoma NOS                                                                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/58 (0%)       0/58 (0%)       0/58 (0%)      |     1/58 (2%)       2/58 (3%)       0/58 (0%)      |
|ADJUSTED (b)           |      0.0%            0.0%            0.0%          |      4.0%            4.8%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |     1/25 (4%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      ---             ---             ---           |      729 (T)         609             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |       (e)             (e)             (e)          |     P=0.285N        P=0.499         P=0.477N       |
|INCIDENTAL TUMOR       |       (e)             (e)             (e)          |     P=0.225N        P=0.629         P=0.477N       |
|LOGISTIC REGRESSION    |       (e)             (e)             (e)          |     P=0.286N        P=0.504         P=0.477N       |
|COCHRAN-ARMITAGE       |       (e)                                          |     P=0.287N                                       |
|FISHER EXACT           |                       (e)             (e)          |                     P=0.500         P=0.500N       |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     2/58 (3%)       4/58 (7%)       4/58 (7%)      |     0/58 (0%)       1/58 (2%)       1/58 (2%)      |
|ADJUSTED (b)           |      9.9%           16.7%           13.3%          |      0.0%            4.0%            2.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       2/21 (10%)      1/18 (6%)      |     0/25 (0%)       1/25 (4%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      572             690             559           |      ---             729 (T)         526           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.468         P=0.516         P=0.447        |     P=0.548         P=0.500         P=0.517        |
|INCIDENTAL TUMOR       |     P=0.428         P=0.375         P=0.369        |     P=0.493         P=0.500         P=0.388        |
|LOGISTIC REGRESSION    |     P=0.430         P=0.416         P=0.358        |     P=0.524         P=0.500         P=0.470        |
|COCHRAN-ARMITAGE       |     P=0.400                                        |     P=0.527                                        |
|FISHER EXACT           |                     P=0.340         P=0.340        |                     P=0.500         P=0.500        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   5
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/58 (0%)       1/58 (2%)       2/58 (3%)      |     1/58 (2%)       1/58 (2%)       0/58 (0%)      |
|ADJUSTED (b)           |      0.0%            2.0%            8.6%          |      4.0%            2.0%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       1/18 (6%)      |     1/25 (4%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      ---             538             650           |      729 (T)         566             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.240         P=0.512         P=0.287        |     P=0.363N        P=0.748N        P=0.477N       |
|INCIDENTAL TUMOR       |     P=0.242         P=0.398         P=0.267        |     P=0.329N        P=0.700N        P=0.477N       |
|LOGISTIC REGRESSION    |     P=0.225         P=0.446         P=0.266        |     P=0.379N        P=0.763         P=0.477N       |
|COCHRAN-ARMITAGE       |     P=0.223                                        |     P=0.378N                                       |
|FISHER EXACT           |                     P=0.500         P=0.248        |                     P=0.752N        P=0.500N       |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     2/58 (3%)       5/58 (9%)       6/58 (10%)     |     1/58 (2%)       2/58 (3%)       1/58 (2%)      |
|ADJUSTED (b)           |      9.9%           18.4%           21.0%          |      4.0%            6.0%            2.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       2/21 (10%)      2/18 (11%)     |     1/25 (4%)       1/25 (4%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      572             538             559           |      729 (T)         566             526           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.246         P=0.367         P=0.223        |     P=0.558N        P=0.512         P=0.738N       |
|INCIDENTAL TUMOR       |     P=0.216         P=0.215         P=0.164        |     P=0.571N        P=0.564         P=0.714        |
|LOGISTIC REGRESSION    |     P=0.208         P=0.258         P=0.155        |     P=0.590N        P=0.509         P=0.759        |
|COCHRAN-ARMITAGE       |     P=0.190                                        |     P=0.587N                                       |
|FISHER EXACT           |                     P=0.219         P=0.136        |                     P=0.500         P=0.752N       |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   6
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Adenoma                                                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     4/58 (7%)       1/58 (2%)       3/58 (5%)      |     0/58 (0%)       0/58 (0%)       0/59 (0%)      |
|ADJUSTED (b)           |     18.5%            2.2%           14.4%          |      0.0%            0.0%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/1 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       0/21 (0%)       2/18 (11%)     |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      574             570             703           |      ---             ---             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.604N        P=0.114N        P=0.354N       |       (e)             (e)             (e)          |
|INCIDENTAL TUMOR       |     P=0.627         P=0.162N        P=0.445N       |       (e)             (e)             (e)          |
|LOGISTIC REGRESSION    |     P=0.634         P=0.170N        P=0.432N       |       (e)             (e)             (e)          |
|COCHRAN-ARMITAGE       |     P=0.611                                        |       (e)                                          |
|FISHER EXACT           |                     P=0.182N        P=0.500N       |                       (e)             (e)          |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Adenoma                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/63 (0%)       3/63 (5%)       6/63 (10%)     |     2/63 (3%)       5/63 (8%)       5/63 (8%)      |
|ADJUSTED (b)           |      0.0%           10.5%           31.6%          |      8.0%           17.8%           16.2%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       5/18 (28%)     |     2/25 (8%)       4/25 (16%)      4/28 (14%)     |
|FIRST INCIDENCE (DAYS) |      ---             549             731           |      729 (T)         594             594           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.033 *       P=0.190         P=0.039 *      |     P=0.372         P=0.221         P=0.260        |
|INCIDENTAL TUMOR       |     P=0.030 *       P=0.071         P=0.032 *      |     P=0.403         P=0.246         P=0.291        |
|LOGISTIC REGRESSION    |     P=0.029 *       P=0.136         P=0.036 *      |     P=0.326         P=0.222         P=0.230        |
|COCHRAN-ARMITAGE       |     P=0.023 *                                      |     P=0.312                                        |
|FISHER EXACT           |                     P=0.122         P=0.014 *      |                     P=0.220         P=0.220        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   7
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma                                                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/63 (0%)       3/63 (5%)       7/63 (11%)     |     0/63 (0%)       0/63 (0%)       4/63 (6%)      |
|ADJUSTED (b)           |      0.0%           10.3%           30.3%          |      0.0%            0.0%           12.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       1/21 (5%)       4/18 (22%)     |     0/25 (0%)       0/25 (0%)       2/28 (7%)      |
|FIRST INCIDENCE (DAYS) |      ---             623             621           |      ---             ---             635           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.015 *       P=0.171         P=0.024 *      |     P=0.012 *         (e)           P=0.070        |
|INCIDENTAL TUMOR       |     P=0.011 *       P=0.164         P=0.016 *      |     P=0.017 *         (e)           P=0.112        |
|LOGISTIC REGRESSION    |     P=0.011 *       P=0.136         P=0.015 *      |     P=0.010 **        (e)           P=0.067        |
|COCHRAN-ARMITAGE       |     P=0.009 **                                     |     P=0.010 **                                     |
|FISHER EXACT           |                     P=0.122         P=0.007 **     |                       (e)           P=0.060        |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/63 (0%)       6/63 (10%)     11/63 (17%)     |     2/63 (3%)       5/63 (8%)       9/63 (14%)     |
|ADJUSTED (b)           |      0.0%           19.7%           48.1%          |      8.0%           17.8%           27.2%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       1/21 (5%)       7/18 (39%)     |     2/25 (8%)       4/25 (16%)      6/28 (21%)     |
|FIRST INCIDENCE (DAYS) |      ---             549             621           |      729 (T)         594             594           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.005 **      P=0.044 *       P=0.003 **     |     P=0.042 *       P=0.221         P=0.038 *      |
|INCIDENTAL TUMOR       |     P=0.003 **      P=0.015 *       P=0.002 **     |     P=0.056         P=0.246         P=0.062        |
|LOGISTIC REGRESSION    |     P=0.003 **      P=0.023 *       P=0.002 **     |     P=0.030 *       P=0.222         P=0.031 *      |
|COCHRAN-ARMITAGE       |     P=0.002 **                                     |     P=0.029 *                                      |
|FISHER EXACT           |                     P=0.014 *       P<0.001 **     |                     P=0.220         P=0.027 *      |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   8
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/63 (0%)       0/63 (0%)       0/63 (0%)      |     1/63 (2%)       3/63 (5%)       0/63 (0%)      |
|ADJUSTED (b)           |      0.0%            0.0%            0.0%          |      4.0%            9.4%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |     1/25 (4%)       1/25 (4%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      ---             ---             ---           |      729 (T)         594             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |       (e)             (e)             (e)          |     P=0.207N        P=0.321         P=0.477N       |
|INCIDENTAL TUMOR       |       (e)             (e)             (e)          |     P=0.224N        P=0.339         P=0.477N       |
|LOGISTIC REGRESSION    |       (e)             (e)             (e)          |     P=0.219N        P=0.315         P=0.477N       |
|COCHRAN-ARMITAGE       |       (e)                                          |     P=0.225N                                       |
|FISHER EXACT           |                       (e)             (e)          |                     P=0.309         P=0.500N       |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     1/63 (2%)       0/63 (0%)       0/63 (0%)      |     2/63 (3%)       3/63 (5%)       0/63 (0%)      |
|ADJUSTED (b)           |      2.8%            0.0%            0.0%          |      6.7%            9.4%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |     1/25 (4%)       1/25 (4%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      596             ---             ---           |      665             594             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.539N        P=0.469N        P=0.489N       |     P=0.133N        P=0.508         P=0.234N       |
|INCIDENTAL TUMOR       |     P=0.557N        P=0.479N        P=0.511N       |     P=0.163N        P=0.517         P=0.299N       |
|LOGISTIC REGRESSION    |     P=0.538N        P=0.500N        P=0.500N       |     P=0.137N        P=0.513         P=0.230N       |
|COCHRAN-ARMITAGE       |     P=0.538N                                       |     P=0.142N                                       |
|FISHER EXACT           |                     P=0.500N        P=0.500N       |                     P=0.500         P=0.248N       |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE   9
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroadenoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     0/63 (0%)       1/63 (2%)       0/63 (0%)      |    22/63 (35%)     11/63 (17%)     10/63 (16%)     |
|ADJUSTED (b)           |      0.0%            2.2%            0.0%          |     57.8%           34.0%           30.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |    11/25 (44%)      6/25 (24%)      6/28 (21%)     |
|FIRST INCIDENCE (DAYS) |      ---             594             ---           |      377             594             594           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.670N        P=0.539           (e)          |     P=0.030N*       P=0.027N*       P=0.010N**     |
|INCIDENTAL TUMOR       |     P=0.688N        P=0.521           (e)          |     P=0.032N*       P=0.011N*       P=0.008N**     |
|LOGISTIC REGRESSION    |     P=0.669N        P=0.499           (e)          |     P=0.033N*       P=0.015N*       P=0.008N**     |
|COCHRAN-ARMITAGE       |     P=0.669N                                       |     P=0.041N*                                      |
|FISHER EXACT           |                     P=0.500           (e)          |                     P=0.021N*       P=0.012N*      |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma or Adenoma                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     1/63 (2%)       1/63 (2%)       0/63 (0%)      |    23/63 (37%)     11/63 (17%)     10/63 (16%)     |
|ADJUSTED (b)           |      2.8%            2.2%            0.0%          |     59.1%           34.0%           30.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |    11/25 (44%)      6/25 (24%)      6/28 (21%)     |
|FIRST INCIDENCE (DAYS) |      596             594             ---           |      377             594             594           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.379N        P=0.721N        P=0.489N       |     P=0.023N*       P=0.019N*       P=0.007N**     |
|INCIDENTAL TUMOR       |     P=0.400N        P=0.740N        P=0.511N       |     P=0.026N*       P=0.007N**      P=0.005N**     |
|LOGISTIC REGRESSION    |     P=0.379N        P=0.762         P=0.500N       |     P=0.024N*       P=0.009N**      P=0.005N**     |
|COCHRAN-ARMITAGE       |     P=0.378N                                       |     P=0.031N*                                      |
|FISHER EXACT           |                     P=0.752N        P=0.500N       |                     P=0.013N*       P=0.007N**     |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  10
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma, Carcinoma, or Adenoma                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     1/63 (2%)       1/63 (2%)       0/63 (0%)      |    24/63 (38%)     13/63 (21%)     10/63 (16%)     |
|ADJUSTED (b)           |      2.8%            2.2%            0.0%          |     62.0%           37.8%           30.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       0/21 (0%)       0/18 (0%)      |    12/25 (48%)      6/25 (24%)      6/28 (21%)     |
|FIRST INCIDENCE (DAYS) |      596             594             ---           |      377             594             594           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.379N        P=0.721N        P=0.489N       |     P=0.012N*       P=0.033N*       P=0.004N**     |
|INCIDENTAL TUMOR       |     P=0.400N        P=0.740N        P=0.511N       |     P=0.012N*       P=0.013N*       P=0.003N**     |
|LOGISTIC REGRESSION    |     P=0.379N        P=0.762         P=0.500N       |     P=0.011N*       P=0.017N*       P=0.003N**     |
|COCHRAN-ARMITAGE       |     P=0.378N                                       |     P=0.016N*                                      |
|FISHER EXACT           |                     P=0.752N        P=0.500N       |                     P=0.025N*       P=0.004N**     |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma, Papilloma Squamous, or Papilloma                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     1/63 (2%)       0/63 (0%)       2/63 (3%)      |     0/63 (0%)       1/63 (2%)       0/63 (0%)      |
|ADJUSTED (b)           |      7.7%            0.0%            6.9%          |      0.0%            2.7%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       0/21 (0%)       0/18 (0%)      |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      733 (T)         ---             621           |      ---             640             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.325         P=0.404N        P=0.598        |     P=0.680N        P=0.480           (e)          |
|INCIDENTAL TUMOR       |     P=0.300         P=0.404N        P=0.523        |     P=0.613N        P=0.612           (e)          |
|LOGISTIC REGRESSION    |     P=0.305         P=0.404N        P=0.544        |     P=0.668N        P=0.503           (e)          |
|COCHRAN-ARMITAGE       |     P=0.287                                        |     P=0.669N                                       |
|FISHER EXACT           |                     P=0.500N        P=0.500        |                     P=0.500           (e)          |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  11
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Ovary                                                                                                                            |
|     Granulosa Cell Tumor Benign                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |     2/59 (3%)       0/59 (0%)       0/59 (0%)      |
|ADJUSTED (b)           |                                                    |      7.0%            0.0%            0.0%          |
|INTERIM SACRIFICE 1 (c)|                                                    |     0/1 (0%)        0/1 (0%)        0/1 (0%)       |
|INTERIM SACRIFICE 2 (c)|                                                    |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |                                                    |     1/25 (4%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |                                                    |      677             ---             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |     P=0.281N        P=0.236N        P=0.227N       |
|INCIDENTAL TUMOR       |                                                    |     P=0.337N        P=0.260N        P=0.299N       |
|LOGISTIC REGRESSION    |                                                    |     P=0.285N        P=0.232N        P=0.230N       |
|COCHRAN-ARMITAGE       |                                                    |     P=0.291N                                       |
|FISHER EXACT           |                                                    |                     P=0.248N        P=0.248N       |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    20/58 (34%)     17/57 (30%)     17/58 (29%)     |    24/57 (42%)     31/58 (53%)     17/58 (29%)     |
|ADJUSTED (b)           |     59.9%           54.1%           46.2%          |     67.1%           71.0%           44.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        1/5 (20%)       2/5 (40%)      |
|TERMINAL (d)           |     4/13 (31%)      9/21 (43%)      4/18 (22%)     |    14/25 (56%)     13/25 (52%)      9/28 (32%)     |
|FIRST INCIDENCE (DAYS) |      521             552             509           |      477             459 (I)         459 (I)       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.300N        P=0.109N        P=0.187N       |     P=0.024N*       P=0.179         P=0.087N       |
|INCIDENTAL TUMOR       |     P=0.370N        P=0.230N        P=0.331N       |     P=0.027N*       P=0.172         P=0.084N       |
|LOGISTIC REGRESSION    |     P=0.406N        P=0.288N        P=0.398N       |     P=0.019N*       P=0.162         P=0.093N       |
|COCHRAN-ARMITAGE       |     P=0.383N                                       |     P=0.023N*                                      |
|FISHER EXACT           |                     P=0.369N        P=0.345N       |                     P=0.151         P=0.108N       |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  12
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal or Sq. Cell Carcinoma, Carcinoma, Basosq. Tumor (M or B), Basal                                                       |
|     Cell Adenoma, Adenoma, Papilloma, Sq Papilloma, Keratoacanthoma, Trichoepithelioma                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     7/63 (11%)      6/63 (10%)      3/63 (5%)      |     0/63 (0%)       0/63 (0%)       1/63 (2%)      |
|ADJUSTED (b)           |     34.0%           24.9%           13.7%          |      0.0%            0.0%            2.9%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     3/13 (23%)      4/21 (19%)      2/18 (11%)     |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      542             638             642           |      ---             ---             663           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.100N        P=0.245N        P=0.084N       |     P=0.328           (e)           P=0.489        |
|INCIDENTAL TUMOR       |     P=0.118N        P=0.375N        P=0.117N       |     P=0.214           (e)           P=0.362        |
|LOGISTIC REGRESSION    |     P=0.109N        P=0.390N        P=0.120N       |     P=0.333           (e)           P=0.504        |
|COCHRAN-ARMITAGE       |     P=0.142N                                       |     P=0.331                                        |
|FISHER EXACT           |                     P=0.500N        P=0.162N       |                       (e)           P=0.500        |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     3/63 (5%)       2/63 (3%)       3/63 (5%)      |     0/63 (0%)       0/63 (0%)       0/63 (0%)      |
|ADJUSTED (b)           |     13.2%            6.7%           12.9%          |      0.0%            0.0%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       1/21 (5%)       2/18 (11%)     |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      573             549             527           |      ---             ---             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.610         P=0.378N        P=0.552N       |       (e)             (e)             (e)          |
|INCIDENTAL TUMOR       |     P=0.581         P=0.529N        P=0.644N       |       (e)             (e)             (e)          |
|LOGISTIC REGRESSION    |     P=0.580         P=0.469N        P=0.629N       |       (e)             (e)             (e)          |
|COCHRAN-ARMITAGE       |     P=0.562                                        |       (e)                                          |
|FISHER EXACT           |                     P=0.500N        P=0.660N       |                       (e)             (e)          |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  13
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     4/63 (6%)       2/63 (3%)       3/63 (5%)      |     1/63 (2%)       1/63 (2%)       1/63 (2%)      |
|ADJUSTED (b)           |     15.5%            6.7%           12.9%          |      2.9%            2.5%            3.6%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       1/21 (5%)       2/18 (11%)     |     0/25 (0%)       0/25 (0%)       1/28 (4%)      |
|FIRST INCIDENCE (DAYS) |      573             549             527           |      665             622             729 (T)       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.537N        P=0.231N        P=0.391N       |     P=0.700N        P=0.751         P=0.754N       |
|INCIDENTAL TUMOR       |     P=0.572N        P=0.353N        P=0.487N       |     P=0.704         P=0.723N        P=0.701        |
|LOGISTIC REGRESSION    |     P=0.569N        P=0.313N        P=0.468N       |     P=0.709N        P=0.759N        P=0.755N       |
|COCHRAN-ARMITAGE       |     P=0.584N                                       |     P=0.713                                        |
|FISHER EXACT           |                     P=0.340N        P=0.500N       |                     P=0.752N        P=0.752N       |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Keratoacanthoma                                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     5/63 (8%)       4/63 (6%)       1/63 (2%)      |     0/63 (0%)       0/63 (0%)       1/63 (2%)      |
|ADJUSTED (b)           |     25.8%           16.7%            5.6%          |      0.0%            0.0%            2.9%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     2/13 (15%)      3/21 (14%)      1/18 (6%)      |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      574             638             733 (T)       |      ---             ---             663           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.067N        P=0.287N        P=0.059N       |     P=0.328           (e)           P=0.489        |
|INCIDENTAL TUMOR       |     P=0.076N        P=0.350N        P=0.077N       |     P=0.214           (e)           P=0.362        |
|LOGISTIC REGRESSION    |     P=0.071N        P=0.405N        P=0.076N       |     P=0.333           (e)           P=0.504        |
|COCHRAN-ARMITAGE       |     P=0.091N                                       |     P=0.331                                        |
|FISHER EXACT           |                     P=0.500N        P=0.104N       |                       (e)           P=0.500        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  14
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     2/63 (3%)       1/63 (2%)       1/63 (2%)      |     0/63 (0%)       0/63 (0%)       0/63 (0%)      |
|ADJUSTED (b)           |      9.7%            4.5%            5.6%          |      0.0%            0.0%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       0/21 (0%)       1/18 (6%)      |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      542             727             733 (T)       |      ---             ---             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.486N        P=0.387N        P=0.420N       |       (e)             (e)             (e)          |
|INCIDENTAL TUMOR       |     P=0.494N        P=0.563N        P=0.450N       |       (e)             (e)             (e)          |
|LOGISTIC REGRESSION    |     P=0.497N        P=0.467N        P=0.470N       |       (e)             (e)             (e)          |
|COCHRAN-ARMITAGE       |     P=0.519N                                       |       (e)                                          |
|FISHER EXACT           |                     P=0.500N        P=0.500N       |                       (e)             (e)          |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, Squamous Cell Carcinoma or Keratoacanthoma                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     7/63 (11%)      5/63 (8%)       2/63 (3%)      |     0/63 (0%)       0/63 (0%)       1/63 (2%)      |
|ADJUSTED (b)           |     34.0%           20.5%           11.1%          |      0.0%            0.0%            2.9%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     3/13 (23%)      3/21 (14%)      2/18 (11%)     |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      542             638             733 (T)       |      ---             ---             663           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.058N        P=0.173N        P=0.038N*      |     P=0.328           (e)           P=0.489        |
|INCIDENTAL TUMOR       |     P=0.067N        P=0.286N        P=0.053N       |     P=0.214           (e)           P=0.362        |
|LOGISTIC REGRESSION    |     P=0.062N        P=0.287N        P=0.057N       |     P=0.333           (e)           P=0.504        |
|COCHRAN-ARMITAGE       |     P=0.083N                                       |     P=0.331                                        |
|FISHER EXACT           |                     P=0.381N        P=0.082N       |                       (e)           P=0.500        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  15
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, or Keratoacanthoma                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     7/63 (11%)      5/63 (8%)       2/63 (3%)      |     0/63 (0%)       0/63 (0%)       1/63 (2%)      |
|ADJUSTED (b)           |     34.0%           20.5%           11.1%          |      0.0%            0.0%            2.9%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     3/13 (23%)      3/21 (14%)      2/18 (11%)     |     0/25 (0%)       0/25 (0%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      542             638             733 (T)       |      ---             ---             663           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.058N        P=0.173N        P=0.038N*      |     P=0.328           (e)           P=0.489        |
|INCIDENTAL TUMOR       |     P=0.067N        P=0.286N        P=0.053N       |     P=0.214           (e)           P=0.362        |
|LOGISTIC REGRESSION    |     P=0.062N        P=0.287N        P=0.057N       |     P=0.333           (e)           P=0.504        |
|COCHRAN-ARMITAGE       |     P=0.083N                                       |     P=0.331                                        |
|FISHER EXACT           |                     P=0.381N        P=0.082N       |                       (e)           P=0.500        |
|=================================================================================================================================|
|                                                                                                                                 |
|Testes                                                                                                                           |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    43/58 (74%)     46/58 (79%)     37/58 (64%)     |                                                    |
|ADJUSTED (b)           |    100.0%           97.8%           91.9%          |                                                    |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |                                                    |
|INTERIM SACRIFICE 2 (c)|     4/5 (80%)       1/5 (20%)       2/5 (40%)      |                                                    |
|TERMINAL (d)           |    13/13 (100%)    20/21 (95%)     15/18 (83%)     |                                                    |
|FIRST INCIDENCE (DAYS) |      458 (I)         455             458 (I)       |                                                    |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.050N*       P=0.124N        P=0.028N*      |                                                    |
|INCIDENTAL TUMOR       |     P=0.017N*       P=0.585         P=0.043N*      |                                                    |
|LOGISTIC REGRESSION    |     P=0.021N*       P=0.560         P=0.059N       |                                                    |
|COCHRAN-ARMITAGE       |     P=0.063N                                       |                                                    |
|FISHER EXACT           |                     P=0.330         P=0.158N       |                                                    |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  16
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     4/57 (7%)       2/58 (3%)       9/58 (16%)     |     3/56 (5%)       4/58 (7%)       4/57 (7%)      |
|ADJUSTED (b)           |     18.1%            7.0%           34.9%          |     10.6%           12.9%           12.2%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       1/21 (5%)       4/18 (22%)     |     2/25 (8%)       2/25 (8%)       2/28 (7%)      |
|FIRST INCIDENCE (DAYS) |      594             599             564           |      665             612             635           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.047 *       P=0.208N        P=0.259        |     P=0.546         P=0.502         P=0.520        |
|INCIDENTAL TUMOR       |     P=0.033 *       P=0.280N        P=0.154        |     P=0.541         P=0.514         P=0.569        |
|LOGISTIC REGRESSION    |     P=0.033 *       P=0.303N        P=0.161        |     P=0.526         P=0.517         P=0.519        |
|COCHRAN-ARMITAGE       |     P=0.029 *                                      |     P=0.515                                        |
|FISHER EXACT           |                     P=0.331N        P=0.126        |                     P=0.520         P=0.510        |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     2/57 (4%)       1/58 (2%)       0/58 (0%)      |     0/56 (0%)       3/58 (5%)       0/57 (0%)      |
|ADJUSTED (b)           |      8.4%            4.8%            0.0%          |      0.0%            9.8%            0.0%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     0/13 (0%)       1/21 (5%)       0/18 (0%)      |     0/25 (0%)       2/25 (8%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |      651             733 (T)         ---           |      ---             538             ---           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.198N        P=0.411N        P=0.200N       |     P=0.334N        P=0.127           (e)          |
|INCIDENTAL TUMOR       |     P=0.204N        P=0.564N        P=0.251N       |     P=0.363N        P=0.099           (e)          |
|LOGISTIC REGRESSION    |     P=0.206N        P=0.444N        P=0.217N       |     P=0.355N        P=0.128           (e)          |
|COCHRAN-ARMITAGE       |     P=0.221N                                       |     P=0.357N                                       |
|FISHER EXACT           |                     P=0.493N        P=0.243N       |                     P=0.128           (e)          |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  17
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |     6/57 (11%)      3/58 (5%)       9/58 (16%)     |     3/56 (5%)       7/58 (12%)      4/57 (7%)      |
|ADJUSTED (b)           |     25.0%           11.7%           34.9%          |     10.6%           22.1%           12.2%          |
|INTERIM SACRIFICE 1 (c)|     0/0             0/0             0/0            |     0/0             0/0             0/0            |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     1/13 (8%)       2/21 (10%)      4/18 (22%)     |     2/25 (8%)       4/25 (16%)      2/28 (7%)      |
|FIRST INCIDENCE (DAYS) |      594             599             564           |      665             538             635           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.173         P=0.127N        P=0.493        |     P=0.482N        P=0.168         P=0.520        |
|INCIDENTAL TUMOR       |     P=0.137         P=0.228N        P=0.336        |     P=0.503N        P=0.152         P=0.569        |
|LOGISTIC REGRESSION    |     P=0.136         P=0.196N        P=0.367        |     P=0.514N        P=0.173         P=0.519        |
|COCHRAN-ARMITAGE       |     P=0.119                                        |     P=0.524N                                       |
|FISHER EXACT           |                     P=0.236N        P=0.303        |                     P=0.175         P=0.510        |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Polyp Stromal                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |     2/63 (3%)       1/63 (2%)       3/63 (5%)      |
|ADJUSTED (b)           |                                                    |      6.0%            4.0%            6.4%          |
|INTERIM SACRIFICE 1 (c)|                                                    |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|                                                    |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |                                                    |     1/25 (4%)       1/25 (4%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |                                                    |      500             729 (T)         444           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |     P=0.369         P=0.495N        P=0.521        |
|INCIDENTAL TUMOR       |                                                    |     P=0.351         P=0.564N        P=0.511        |
|LOGISTIC REGRESSION    |                                                    |     P=0.344         P=0.493N        P=0.495        |
|COCHRAN-ARMITAGE       |                                                    |     P=0.344                                        |
|FISHER EXACT           |                                                    |                     P=0.500N        P=0.500        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  18
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Sarcoma Stromal or Polyp Stromal                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |     2/63 (3%)       1/63 (2%)       4/63 (6%)      |
|ADJUSTED (b)           |                                                    |      6.0%            4.0%            8.1%          |
|INTERIM SACRIFICE 1 (c)|                                                    |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|                                                    |     0/5 (0%)        0/5 (0%)        1/5 (20%)      |
|TERMINAL (d)           |                                                    |     1/25 (4%)       1/25 (4%)       0/28 (0%)      |
|FIRST INCIDENCE (DAYS) |                                                    |      500             729 (T)         444           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |     P=0.201         P=0.495N        P=0.359        |
|INCIDENTAL TUMOR       |                                                    |     P=0.186         P=0.564N        P=0.343        |
|LOGISTIC REGRESSION    |                                                    |     P=0.179         P=0.493N        P=0.329        |
|COCHRAN-ARMITAGE       |                                                    |     P=0.181                                        |
|FISHER EXACT           |                                                    |                     P=0.500N        P=0.340        |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    28/63 (44%)     32/63 (51%)     36/63 (57%)     |    19/63 (30%)     18/63 (29%)     22/63 (35%)     |
|ADJUSTED (b)           |     78.9%           71.9%           81.4%          |     46.6%           48.3%           50.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        1/5 (20%)      |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|TERMINAL (d)           |     7/13 (54%)      9/21 (43%)     11/18 (61%)     |     6/25 (24%)      8/25 (32%)      8/28 (29%)     |
|FIRST INCIDENCE (DAYS) |      539             455             408           |      263             452             501           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.331         P=0.347N        P=0.466        |     P=0.375         P=0.499N        P=0.437        |
|INCIDENTAL TUMOR       |     P=0.125         P=0.252         P=0.122        |     P=0.183         P=0.567         P=0.235        |
|LOGISTIC REGRESSION    |     P=0.105         P=0.326         P=0.149        |     P=0.288         P=0.469N        P=0.373        |
|COCHRAN-ARMITAGE       |     P=0.119                                        |     P=0.277                                        |
|FISHER EXACT           |                     P=0.296         P=0.106        |                     P=0.500N        P=0.352        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  19
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Benign Tumors                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    53/63 (84%)     53/63 (84%)     52/63 (83%)     |    37/63 (59%)     46/63 (73%)     48/63 (76%)     |
|ADJUSTED (b)           |    100.0%          100.0%          100.0%          |     83.1%           97.8%           94.0%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     4/5 (80%)       1/5 (20%)       2/5 (40%)      |     0/5 (0%)        1/5 (20%)       3/5 (60%)      |
|TERMINAL (d)           |    13/13 (100%)    21/21 (100%)    18/18 (100%)    |    18/25 (72%)     24/25 (96%)     25/28 (89%)     |
|FIRST INCIDENCE (DAYS) |      458 (I)         455             458 (I)       |      377             459 (I)         444           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.243N        P=0.059N        P=0.103N       |     P=0.254         P=0.131         P=0.150        |
|INCIDENTAL TUMOR       |     P=0.205N        P=0.212N        P=0.159N       |     P=0.034 *       P=0.063         P=0.024 *      |
|LOGISTIC REGRESSION    |     P=0.286N        P=0.349N        P=0.245N       |     P=0.046 *       P=0.073         P=0.025 *      |
|COCHRAN-ARMITAGE       |     P=0.466N                                       |     P=0.064                                        |
|FISHER EXACT           |                     P=0.596N        P=0.500N       |                     P=0.066         P=0.028 *      |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Tumors                                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    33/63 (52%)     37/63 (59%)     46/63 (73%)     |    25/63 (40%)     31/63 (49%)     29/63 (46%)     |
|ADJUSTED (b)           |     81.3%           78.2%           95.5%          |     56.9%           66.8%           62.6%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     0/5 (0%)        0/5 (0%)        1/5 (20%)      |     1/5 (20%)       1/5 (20%)       1/5 (20%)      |
|TERMINAL (d)           |     7/13 (54%)     11/21 (52%)     16/18 (89%)     |     8/25 (32%)     11/25 (44%)     12/28 (43%)     |
|FIRST INCIDENCE (DAYS) |      361             455             408           |      263             452             459 (I)       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.146         P=0.318N        P=0.300        |     P=0.526         P=0.247         P=0.408        |
|INCIDENTAL TUMOR       |     P=0.005 **      P=0.178         P=0.006 **     |     P=0.344         P=0.170         P=0.219        |
|LOGISTIC REGRESSION    |     P=0.008 **      P=0.337         P=0.017 *      |     P=0.426         P=0.232         P=0.323        |
|COCHRAN-ARMITAGE       |     P=0.012 *                                      |     P=0.416                                        |
|FISHER EXACT           |                     P=0.295         P=0.013 *      |                     P=0.185         P=0.295        |
|=================================================================================================================================|
         DATE: 05/19/95                     EXPERIMENT: 05107 TEST: 05                                                 PAGE  20
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NICKEL SUBSULFIDE
                                                 TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |      0.0MG/M3        0.15            1.0           |      0.0MG/M3        0.15            1.0           |
|                       |      LUNG TOX        LUNG TOX        LUNG TOX      |      LUNG TOX        LUNG TOX        LUNG TOX      |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant and Benign Tumors                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |       #               #               #            |       #               #               #            |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |    56/63 (89%)     53/63 (84%)     56/63 (89%)     |    49/63 (78%)     53/63 (84%)     52/63 (83%)     |
|ADJUSTED (b)           |    100.0%          100.0%          100.0%          |     90.7%           98.1%           94.5%          |
|INTERIM SACRIFICE 1 (c)|     0/5 (0%)        0/5 (0%)        0/5 (0%)       |     0/5 (0%)        0/5 (0%)        0/5 (0%)       |
|INTERIM SACRIFICE 2 (c)|     4/5 (80%)       1/5 (20%)       3/5 (60%)      |     1/5 (20%)       2/5 (40%)       4/5 (80%)      |
|TERMINAL (d)           |    13/13 (100%)    21/21 (100%)    18/18 (100%)    |    20/25 (80%)     24/25 (96%)     25/28 (89%)     |
|FIRST INCIDENCE (DAYS) |      361             455             408           |      263             452             444           |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |     P=0.346N        P=0.030N*       P=0.132N       |     P=0.449N        P=0.371         P=0.550        |
|INCIDENTAL TUMOR       |     P=0.549         P=0.046N*       P=0.500N       |     P=0.293         P=0.133         P=0.212        |
|LOGISTIC REGRESSION    |     P=0.611         P=0.023N*       P=0.384N       |     P=0.429         P=0.334         P=0.354        |
|COCHRAN-ARMITAGE       |     P=0.446                                        |     P=0.417                                        |
|FISHER EXACT           |                     P=0.302N        P=0.611N       |                     P=0.248         P=0.328        |
|=================================================================================================================================|
 (a)  Number of tumor-bearing animals / number of animals examined at site.
 (b)  Kaplan-Meier estimated lifetime tumor incidence after adjustment for 
      intercurrent mortality.
 (c)  Observed incidence at interim kill.
          Male interim sacrifices(days):   199  458
          Female interim sacrifices(days): 200  459
 (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.  The incidental tumor 
      test regards these lesions as non-fatal.  Logistic regression is an alternative
      method for analyzing the incidence of non-fatal tumors.  The Cochran-Armitage
      and Fisher's 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).