Skip to Main Navigation
Skip to Page Content
Share This:
https://ntp.niehs.nih.gov/go/6100

TDMS Study 05200-05 Pathology Tables

NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Northwest                                       NITROMETHANE                                     DATE: 04/04/96       
EXPERIMENT: 05200 TEST: 05                                                                                     TIME: 05:44:52       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: N01-ES-75189                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: C61927       
PATHOLOGIST: R. MILLER                       R. RENNE                                                          CAS: 75-52-5         
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    

               REASONS FOR REMOVAL:    ALL                                                                                          
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       INCLUDE ALL                                                                                  
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Northwest                                       NITROMETHANE                                     DATE: 04/04/96       
EXPERIMENT: 05200 TEST: 05                                                                                     TIME: 05:44:52       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01-ES-75189                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: C61927       
PATHOLOGIST: R. MILLER                       R. RENNE                                                          CAS: 75-52-5         




                                                    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: Battelle Northwest                                       NITROMETHANE                                     DATE: 04/04/96       
EXPERIMENT: 05200 TEST: 05                                                                                     TIME: 05:44:52       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01-ES-75189                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: C61927       
PATHOLOGIST: R. MILLER                       R. RENNE                                                          CAS: 75-52-5         




                                     SUMMARY OF STATISTICALLY SIGNIFICANT (P<=.05) RESULTS
                                          IN THE ANALYSIS OF THE STUDY OF NITROMETHANE

              ====================================================================================================

                                                           MALE RATS
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------

              Islets, Pancreatic            Adenoma
                                            Carcinoma
              Skin                          Basal Cell Carcinoma
                                            Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma
                                            Fibrosarcoma
                                            Schwannoma Malignant
                                            Squamous Cell Papilloma
              All Organs                    Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                            Benign Tumors

              ====================================================================================================

                                                           FEMALE RATS
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------

              Mammary Gland                 Carcinoma
                                            Carcinoma or Adenoma
                                            Fibroadenoma
                                            Fibroma, Fibroadenoma or Adenoma
                                            Fibroma, Fibroadenoma, Carcinoma, or Adenoma
              Pituitary Gland: Pars Distalis or Unspecified Site
                                            Adenoma
                                            Carcinoma or Adenoma
              Uterus                        Polyp Stromal
                                            Sarcoma Stromal or Polyp Stromal
              All Organs                    Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                            Benign Tumors
                                            Malignant and Benign Tumors

              ====================================================================================================
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   1
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Benign                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 16/50 (32%)  20/50 (40%)  21/50 (42%)  19/50 (38%) |  1/49 (2%)    1/50 (2%)    2/49 (4%)    4/50 (8%)  |
|ADJUSTED (b)           |  71.6%        72.9%        77.2%        70.4%      |   3.6%         5.3%         6.9%        13.5%      |
|TERMINAL (d)           |  7/13 (54%)   9/16 (56%)   9/14 (64%)   2/8 (25%)  |  1/28 (4%)    1/19 (5%)    2/29 (7%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   611          574          499          544       |   733 (T)      733 (T)      733 (T)      651       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.098      P=0.338      P=0.239      P=0.101    |  P=0.065      P=0.673      P=0.512      P=0.147    |
|INCIDENTAL TUMOR       |  P=0.392      P=0.133      P=0.205      P=0.384    |  P=0.075      P=0.673      P=0.512      P=0.205    |
|LOGISTIC REGRESSION    |  P=0.302      P=0.141      P=0.167      P=0.260    |  P=0.067      P=0.673      P=0.512      P=0.167    |
|COCHRAN-ARMITAGE       |  P=0.346                                           |  P=0.074                                           |
|FISHER EXACT           |               P=0.266      P=0.204      P=0.338    |               P=0.747N     P=0.500      P=0.187    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Malignant                                                                                                  |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    2/50 (4%)    2/50 (4%)  |  0/49 (0%)    0/50 (0%)    1/49 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   7.7%         6.3%        10.5%        14.1%      |   0.0%         0.0%         3.4%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    1/16 (6%)    1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    1/29 (3%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   733 (T)      733 (T)      643          698       |   ---          ---          733 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.216      P=0.717N     P=0.509      P=0.362    |  P=0.683        (e)        P=0.507        (e)      |
|INCIDENTAL TUMOR       |  P=0.309      P=0.717N     P=0.540      P=0.511    |  P=0.683        (e)        P=0.507        (e)      |
|LOGISTIC REGRESSION    |  P=0.287      P=0.717N     P=0.487      P=0.427    |  P=0.683        (e)        P=0.507        (e)      |
|COCHRAN-ARMITAGE       |  P=0.337                                           |  P=0.695                                           |
|FISHER EXACT           |               P=0.753N     P=0.500      P=0.500    |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   2
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma: Benign, Complex, Malignant, NOS                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 17/50 (34%)  21/50 (42%)  22/50 (44%)  20/50 (40%) |  2/49 (4%)    1/50 (2%)    3/49 (6%)    4/50 (8%)  |
|ADJUSTED (b)           |  76.3%        76.8%        78.0%        72.2%      |   7.1%         5.3%        10.3%        13.5%      |
|TERMINAL (d)           |  8/13 (62%)  10/16 (63%)   9/14 (64%)   2/8 (25%)  |  2/28 (7%)    1/19 (5%)    3/29 (10%)   1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   611          574          499          544       |   733 (T)      733 (T)      733 (T)      651       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.093      P=0.352      P=0.243      P=0.094    |  P=0.145      P=0.635N     P=0.516      P=0.277    |
|INCIDENTAL TUMOR       |  P=0.383      P=0.141      P=0.215      P=0.376    |  P=0.162      P=0.635N     P=0.516      P=0.356    |
|LOGISTIC REGRESSION    |  P=0.301      P=0.129      P=0.168      P=0.254    |  P=0.150      P=0.635N     P=0.516      P=0.310    |
|COCHRAN-ARMITAGE       |  P=0.348                                           |  P=0.166                                           |
|FISHER EXACT           |               P=0.268      P=0.206      P=0.339    |               P=0.492N     P=0.500      P=0.349    |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  4/50 (8%)    3/50 (6%)    3/50 (6%)    3/50 (6%)  |  7/47 (15%)   4/46 (9%)    6/47 (13%)   2/48 (4%)  |
|ADJUSTED (b)           |  15.4%        11.6%        13.1%        24.1%      |  25.0%        19.3%        17.3%         9.1%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    1/14 (7%)    1/8 (13%)  |  6/26 (23%)   3/18 (17%)   3/28 (11%)   2/22 (9%)  |
|FIRST INCIDENCE (DAYS) |   528          574          560          650       |   631          636          619          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.530N     P=0.544N     P=0.508N     P=0.631N   |  P=0.096N     P=0.474N     P=0.449N     P=0.117N   |
|INCIDENTAL TUMOR       |  P=0.347N     P=0.606N     P=0.509N     P=0.443N   |  P=0.083N     P=0.436N     P=0.592N     P=0.105N   |
|LOGISTIC REGRESSION    |  P=0.443N     P=0.503N     P=0.499N     P=0.512N   |  P=0.087N     P=0.386N     P=0.505N     P=0.102N   |
|COCHRAN-ARMITAGE       |  P=0.442N                                          |  P=0.082N                                          |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.500N   |               P=0.274N     P=0.500N     P=0.074N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   3
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |  0/47 (0%)    1/46 (2%)    3/47 (6%)    0/48 (0%)  |
|ADJUSTED (b)           |   0.0%         4.3%         2.1%         4.2%      |   0.0%         5.6%        10.7%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/26 (0%)    1/18 (6%)    3/28 (11%)   0/22 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          665          492          664       |   ---          733 (T)      733 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.372      P=0.483      P=0.508      P=0.477    |  P=0.620      P=0.427      P=0.133        (e)      |
|INCIDENTAL TUMOR       |  P=0.453      P=0.419      P=0.469      P=0.557    |  P=0.620      P=0.427      P=0.133        (e)      |
|LOGISTIC REGRESSION    |  P=0.375      P=0.493      P=0.414      P=0.497    |  P=0.620      P=0.427      P=0.133        (e)      |
|COCHRAN-ARMITAGE       |  P=0.383                                           |  P=0.626N                                          |
|FISHER EXACT           |               P=0.500      P=0.500      P=0.500    |               P=0.495      P=0.121        (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  4/50 (8%)    4/50 (8%)    4/50 (8%)    4/50 (8%)  |  7/47 (15%)   5/46 (11%)   9/47 (19%)   2/48 (4%)  |
|ADJUSTED (b)           |  15.4%        15.4%        14.9%        27.2%      |  25.0%        24.7%        27.2%         9.1%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    1/14 (7%)    1/8 (13%)  |  6/26 (23%)   4/18 (22%)   6/28 (21%)   2/22 (9%)  |
|FIRST INCIDENCE (DAYS) |   528          574          492          650       |   631          636          619          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.484      P=0.593      P=0.634      P=0.510    |  P=0.116N     P=0.625N     P=0.451      P=0.117N   |
|INCIDENTAL TUMOR       |  P=0.448N     P=0.519      P=0.624      P=0.572N   |  P=0.102N     P=0.590N     P=0.320      P=0.105N   |
|LOGISTIC REGRESSION    |  P=0.569N     P=0.639      P=0.637      P=0.633    |  P=0.106N     P=0.534N     P=0.387      P=0.102N   |
|COCHRAN-ARMITAGE       |  P=0.570                                           |  P=0.099N                                          |
|FISHER EXACT           |               P=0.643N     P=0.643N     P=0.643N   |               P=0.395N     P=0.392      P=0.074N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   4
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  8/50 (16%)   9/50 (18%)   4/50 (8%)    1/50 (2%)  |  1/50 (2%)    1/50 (2%)    3/50 (6%)    1/50 (2%)  |
|ADJUSTED (b)           |  26.9%        40.6%        20.0%         4.5%      |   3.6%         2.6%        10.0%         4.3%      |
|TERMINAL (d)           |  0/13 (0%)    5/16 (31%)   2/14 (14%)   0/8 (0%)   |  1/28 (4%)    0/19 (0%)    3/30 (10%)   1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   552          601          590          681       |   733 (T)      580          733 (T)      733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.014N*    P=0.509      P=0.191N     P=0.029N*  |  P=0.536      P=0.706      P=0.329      P=0.718    |
|INCIDENTAL TUMOR       |  P=0.005N**   P=0.448      P=0.161N     P=0.007N** |  P=0.540      P=0.763N     P=0.329      P=0.718    |
|LOGISTIC REGRESSION    |  P=0.006N**   P=0.472      P=0.177N     P=0.018N*  |  P=0.546      P=0.756N     P=0.329      P=0.718    |
|COCHRAN-ARMITAGE       |  P=0.006N**                                        |  P=0.555                                           |
|FISHER EXACT           |               P=0.500      P=0.178N     P=0.015N*  |               P=0.753N     P=0.309      P=0.753N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    3/50 (6%)    5/50 (10%) |  0/50 (0%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   7.7%         5.9%        14.2%        25.9%      |   0.0%         2.1%         0.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/16 (0%)    1/14 (7%)    1/8 (13%)  |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   733 (T)      714          621          634       |   ---          488          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.016 *    P=0.750N     P=0.318      P=0.068    |  P=0.568N     P=0.492        (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.042 *    P=0.741      P=0.324      P=0.101    |  P=0.614N     P=0.567        (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.026 *    P=0.747      P=0.297      P=0.089    |  P=0.491N     P=0.701        (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.031 *                                         |  P=0.567N                                          |
|FISHER EXACT           |               P=0.753N     P=0.309      P=0.102    |               P=0.500        (e)          (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   5
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  9/50 (18%)  10/50 (20%)   7/50 (14%)   6/50 (12%) |  1/50 (2%)    2/50 (4%)    3/50 (6%)    1/50 (2%)  |
|ADJUSTED (b)           |  32.5%        44.1%        32.2%        29.3%      |   3.6%         4.6%        10.0%         4.3%      |
|TERMINAL (d)           |  1/13 (8%)    5/16 (31%)   3/14 (21%)   1/8 (13%)  |  1/28 (4%)    0/19 (0%)    3/30 (10%)   1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   552          601          590          634       |   733 (T)      488          733 (T)      733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.308N     P=0.513      P=0.393N     P=0.388N   |  P=0.596N     P=0.440      P=0.329      P=0.718    |
|INCIDENTAL TUMOR       |  P=0.148N     P=0.440      P=0.361N     P=0.209N   |  P=0.602      P=0.541      P=0.329      P=0.718    |
|LOGISTIC REGRESSION    |  P=0.186N     P=0.462      P=0.389N     P=0.294N   |  P=0.579N     P=0.604      P=0.329      P=0.718    |
|COCHRAN-ARMITAGE       |  P=0.181N                                          |  P=0.578N                                          |
|FISHER EXACT           |               P=0.500      P=0.393N     P=0.288N   |               P=0.500      P=0.309      P=0.753N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    3/50 (6%)    2/50 (4%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%        14.9%        14.3%        12.5%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    1/16 (6%)    2/14 (14%)   1/8 (13%)  |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          636          733 (T)      733 (T)   |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.399      P=0.125      P=0.252      P=0.403    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.470      P=0.111      P=0.252      P=0.403    |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.487      P=0.107      P=0.252      P=0.403    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.555                                           |    (e)                                             |
|FISHER EXACT           |               P=0.121      P=0.247      P=0.500    |                 (e)          (e)          (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   6
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    3/50 (6%)    2/50 (4%)    1/50 (2%)  |  1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%        14.9%        14.3%        12.5%      |   2.9%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    1/16 (6%)    2/14 (14%)   1/8 (13%)  |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          636          733 (T)      733 (T)   |   691          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.399      P=0.125      P=0.252      P=0.403    |  P=0.321N     P=0.561N     P=0.500N     P=0.546N   |
|INCIDENTAL TUMOR       |  P=0.470      P=0.111      P=0.252      P=0.403    |  P=0.280N     P=0.443N     P=0.479N     P=0.443N   |
|LOGISTIC REGRESSION    |  P=0.487      P=0.107      P=0.252      P=0.403    |  P=0.306N     P=0.520N     P=0.501N     P=0.506N   |
|COCHRAN-ARMITAGE       |  P=0.555                                           |  P=0.304N                                          |
|FISHER EXACT           |               P=0.121      P=0.247      P=0.500    |               P=0.500N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Adenoma                                                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   2.2%         4.0%         3.4%        14.5%      |   2.8%         2.9%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   504          650          639          656       |   658          621          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.326      P=0.743      P=0.757      P=0.447    |  P=0.237N     P=0.725      P=0.495N     P=0.511N   |
|INCIDENTAL TUMOR       |  P=0.441      P=0.746      P=0.757N     P=0.567    |  P=0.222N     P=0.681N     P=0.479N     P=0.443N   |
|LOGISTIC REGRESSION    |  P=0.350      P=0.753N     P=0.740      P=0.500    |  P=0.230N     P=0.740N     P=0.495N     P=0.492N   |
|COCHRAN-ARMITAGE       |  P=0.351                                           |  P=0.235N                                          |
|FISHER EXACT           |               P=0.753N     P=0.753N     P=0.500    |               P=0.753N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   7
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma                                                                                                    |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    2/50 (4%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         5.8%         0.0%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          509          ---       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.597        (e)        P=0.238        (e)      |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.623        (e)        P=0.208        (e)      |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.576        (e)        P=0.212        (e)      |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.593                                           |    (e)                                             |
|FISHER EXACT           |                 (e)        P=0.247        (e)      |                 (e)          (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma or Hepatocellular Adenoma                                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    3/50 (6%)    2/50 (4%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   2.2%         4.0%         9.0%        14.5%      |   2.8%         2.9%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   504          650          509          656       |   658          621          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.307      P=0.743      P=0.304      P=0.447    |  P=0.237N     P=0.725      P=0.495N     P=0.511N   |
|INCIDENTAL TUMOR       |  P=0.418      P=0.746      P=0.282      P=0.567    |  P=0.222N     P=0.681N     P=0.479N     P=0.443N   |
|LOGISTIC REGRESSION    |  P=0.319      P=0.753N     P=0.264      P=0.500    |  P=0.230N     P=0.740N     P=0.495N     P=0.492N   |
|COCHRAN-ARMITAGE       |  P=0.324                                           |  P=0.235N                                          |
|FISHER EXACT           |               P=0.753N     P=0.309      P=0.500    |               P=0.753N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   8
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma, Hepatocellular Adenoma, or Hepatoblastoma                                                         |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    3/50 (6%)    2/50 (4%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   2.2%         4.0%         9.0%        14.5%      |   2.8%         2.9%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   504          650          509          656       |   658          621          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.307      P=0.743      P=0.304      P=0.447    |  P=0.237N     P=0.725      P=0.495N     P=0.511N   |
|INCIDENTAL TUMOR       |  P=0.418      P=0.746      P=0.282      P=0.567    |  P=0.222N     P=0.681N     P=0.479N     P=0.443N   |
|LOGISTIC REGRESSION    |  P=0.319      P=0.753N     P=0.264      P=0.500    |  P=0.230N     P=0.740N     P=0.495N     P=0.492N   |
|COCHRAN-ARMITAGE       |  P=0.324                                           |  P=0.235N                                          |
|FISHER EXACT           |               P=0.753N     P=0.309      P=0.500    |               P=0.753N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Adenoma                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    0/50 (0%)    3/50 (6%)  |  0/50 (0%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |
|ADJUSTED (b)           |   7.7%        12.5%         0.0%         8.2%      |   0.0%         3.1%         2.4%         3.3%      |
|TERMINAL (d)           |  1/13 (8%)    2/16 (13%)   0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   733 (T)      733 (T)      ---          544       |   ---          636          638          672       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.178      P=0.574      P=0.485N     P=0.278    |  P=0.386      P=0.471      P=0.520      P=0.469    |
|INCIDENTAL TUMOR       |  P=0.167      P=0.574      P=0.485N     P=0.276    |  P=0.425      P=0.581      P=0.227      P=0.557    |
|LOGISTIC REGRESSION    |  P=0.239      P=0.574      P=0.485N     P=0.305    |  P=0.387      P=0.528      P=0.512      P=0.502    |
|COCHRAN-ARMITAGE       |  P=0.242                                           |  P=0.383                                           |
|FISHER EXACT           |               P=0.500      P=0.500N     P=0.309    |               P=0.500      P=0.500      P=0.500    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE   9
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma                                                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    2/50 (4%)    0/50 (0%)  |  1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%        10.6%         0.0%      |   3.2%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          650          ---       |   714          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.550        (e)        P=0.244        (e)      |  P=0.320N     P=0.568N     P=0.507N     P=0.543N   |
|INCIDENTAL TUMOR       |  P=0.592        (e)        P=0.232        (e)      |  P=0.280N     P=0.443N     P=0.479N     P=0.443N   |
|LOGISTIC REGRESSION    |  P=0.581        (e)        P=0.233        (e)      |  P=0.309N     P=0.542N     P=0.500N     P=0.519N   |
|COCHRAN-ARMITAGE       |  P=0.593                                           |  P=0.304N                                          |
|FISHER EXACT           |                 (e)        P=0.247        (e)      |               P=0.500N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    2/50 (4%)    3/50 (6%)  |  1/50 (2%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |
|ADJUSTED (b)           |   7.7%        12.5%        10.6%         8.2%      |   3.2%         3.1%         2.4%         3.3%      |
|TERMINAL (d)           |  1/13 (8%)    2/16 (13%)   1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   733 (T)      733 (T)      650          544       |   714          636          638          672       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.160      P=0.574      P=0.513      P=0.278    |  P=0.626      P=0.706      P=0.753N     P=0.719    |
|INCIDENTAL TUMOR       |  P=0.169      P=0.574      P=0.501      P=0.276    |  P=0.583N     P=0.681N     P=0.638      P=0.700N   |
|LOGISTIC REGRESSION    |  P=0.225      P=0.574      P=0.485      P=0.305    |  P=0.632N     P=0.760      P=0.762N     P=0.755    |
|COCHRAN-ARMITAGE       |  P=0.232                                           |  P=0.633                                           |
|FISHER EXACT           |               P=0.500      P=0.500      P=0.309    |               P=0.753N     P=0.753N     P=0.753N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  10
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  2/50 (4%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |   7.1%         0.0%         0.0%         8.7%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  2/28 (7%)    0/19 (0%)    0/30 (0%)    2/23 (9%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   733 (T)      ---          ---          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.479      P=0.327N     P=0.223N     P=0.624    |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.479      P=0.327N     P=0.223N     P=0.624    |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.479      P=0.327N     P=0.223N     P=0.624    |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.501                                           |
|FISHER EXACT           |                 (e)          (e)          (e)      |               P=0.247N     P=0.247N     P=0.691N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  2/50 (4%)    7/50 (14%)   1/50 (2%)   11/50 (22%) |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |   6.0%        29.3%         2.0%        33.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  1/28 (4%)    4/19 (21%)   0/30 (0%)    5/23 (22%) |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   631          588          440          425       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.009 **   P=0.032 *    P=0.489N     P=0.006 ** |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.009 **   P=0.066      P=0.582N     P=0.008 ** |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.009 **   P=0.052      P=0.447N     P=0.011 *  |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.009 **                                        |
|FISHER EXACT           |                 (e)          (e)          (e)      |               P=0.080      P=0.500N     P=0.007 ** |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  11
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  4/50 (8%)    7/50 (14%)   1/50 (2%)   13/50 (26%) |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |  13.0%        29.3%         2.0%        40.5%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  3/28 (11%)   4/19 (21%)   0/30 (0%)    7/23 (30%) |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   631          588          440          425       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.009 **   P=0.116      P=0.169N     P=0.009 ** |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.009 **   P=0.195      P=0.206N     P=0.012 *  |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.010 **   P=0.176      P=0.169N     P=0.018 *  |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.009 **                                        |
|FISHER EXACT           |                 (e)          (e)          (e)      |               P=0.262      P=0.181N     P=0.016 *  |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroadenoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  | 19/50 (38%)  21/50 (42%)  33/50 (66%)  36/50 (72%) |
|ADJUSTED (b)           |   7.7%         6.3%         3.7%        18.0%      |  58.2%        68.5%        80.0%        92.1%      |
|TERMINAL (d)           |  1/13 (8%)    1/16 (6%)    0/14 (0%)    1/8 (13%)  | 15/28 (54%)  10/19 (53%)  22/30 (73%)  20/23 (87%) |
|FIRST INCIDENCE (DAYS) |   733 (T)      733 (T)      650          698       |   454          435          468          552       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.244      P=0.717N     P=0.756N     P=0.362    |  P<0.001 **   P=0.076      P=0.015 *    P<0.001 ** |
|INCIDENTAL TUMOR       |  P=0.314      P=0.717N     P=0.753      P=0.421    |  P<0.001 **   P=0.229      P=0.005 **   P<0.001 ** |
|LOGISTIC REGRESSION    |  P=0.300      P=0.717N     P=0.759      P=0.387    |  P<0.001 **   P=0.219      P=0.003 **   P<0.001 ** |
|COCHRAN-ARMITAGE       |  P=0.351                                           |  P<0.001 **                                        |
|FISHER EXACT           |               P=0.753N     P=0.753N     P=0.500    |               P=0.419      P=0.004 **   P<0.001 ** |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  12
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma or Adenoma                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  | 20/50 (40%)  21/50 (42%)  33/50 (66%)  36/50 (72%) |
|ADJUSTED (b)           |   7.7%         6.3%         3.7%        18.0%      |  61.4%        68.5%        80.0%        92.1%      |
|TERMINAL (d)           |  1/13 (8%)    1/16 (6%)    0/14 (0%)    1/8 (13%)  | 16/28 (57%)  10/19 (53%)  22/30 (73%)  20/23 (87%) |
|FIRST INCIDENCE (DAYS) |   733 (T)      733 (T)      650          698       |   454          435          468          552       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.244      P=0.717N     P=0.756N     P=0.362    |  P<0.001 **   P=0.101      P=0.024 *    P<0.001 ** |
|INCIDENTAL TUMOR       |  P=0.314      P=0.717N     P=0.753      P=0.421    |  P<0.001 **   P=0.285      P=0.009 **   P<0.001 ** |
|LOGISTIC REGRESSION    |  P=0.300      P=0.717N     P=0.759      P=0.387    |  P<0.001 **   P=0.278      P=0.006 **   P<0.001 ** |
|COCHRAN-ARMITAGE       |  P=0.351                                           |  P<0.001 **                                        |
|FISHER EXACT           |               P=0.753N     P=0.753N     P=0.500    |               P=0.500      P=0.008 **   P=0.001 ** |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma, Carcinoma, or Adenoma                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  | 21/50 (42%)  25/50 (50%)  34/50 (68%)  41/50 (82%) |
|ADJUSTED (b)           |   7.7%         6.3%         3.7%        18.0%      |  62.4%        74.9%        80.4%        95.2%      |
|TERMINAL (d)           |  1/13 (8%)    1/16 (6%)    0/14 (0%)    1/8 (13%)  | 16/28 (57%)  11/19 (58%)  22/30 (73%)  21/23 (91%) |
|FIRST INCIDENCE (DAYS) |   733 (T)      733 (T)      650          698       |   454          435          440          425       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.244      P=0.717N     P=0.756N     P=0.362    |  P<0.001 **   P=0.032 *    P=0.028 *    P<0.001 ** |
|INCIDENTAL TUMOR       |  P=0.314      P=0.717N     P=0.753      P=0.421    |  P<0.001 **   P=0.138      P=0.008 **   P<0.001 ** |
|LOGISTIC REGRESSION    |  P=0.300      P=0.717N     P=0.759      P=0.387    |  P<0.001 **   P=0.112      P=0.006 **   P<0.001 ** |
|COCHRAN-ARMITAGE       |  P=0.351                                           |  P<0.001 **                                        |
|FISHER EXACT           |               P=0.753N     P=0.753N     P=0.500    |               P=0.274      P=0.008 **   P<0.001 ** |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  13
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma, Papilloma Squamous, or Papilloma                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    2/50 (4%)    1/50 (2%)    1/50 (2%)  |  1/50 (2%)    0/50 (0%)    2/50 (4%)    1/50 (2%)  |
|ADJUSTED (b)           |   0.0%         8.3%         7.1%         4.3%      |   3.1%         0.0%         5.2%         4.3%      |
|TERMINAL (d)           |  0/13 (0%)    1/16 (6%)    1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          490          733 (T)      675       |   713          ---          545          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.427      P=0.258      P=0.515      P=0.500    |  P=0.475      P=0.575N     P=0.487      P=0.710    |
|INCIDENTAL TUMOR       |  P=0.453      P=0.291      P=0.515      P=0.557    |  P=0.507      P=0.443N     P=0.579      P=0.752N   |
|LOGISTIC REGRESSION    |  P=0.499      P=0.242      P=0.515      P=0.493    |  P=0.499      P=0.541N     P=0.513      P=0.734    |
|COCHRAN-ARMITAGE       |  P=0.499                                           |  P=0.499                                           |
|FISHER EXACT           |               P=0.247      P=0.500      P=0.500    |               P=0.500N     P=0.500      P=0.753N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 38/50 (76%)  36/47 (77%)  32/50 (64%)  39/49 (80%) | 33/50 (66%)  36/50 (72%)  39/50 (78%)  40/50 (80%) |
|ADJUSTED (b)           | 100.0%        97.1%        84.6%        97.1%      |  74.2%        91.8%        88.5%        88.5%      |
|TERMINAL (d)           | 13/13 (100%) 15/16 (94%)   9/14 (64%)   7/8 (88%)  | 17/28 (61%)  16/19 (84%)  25/30 (83%)  18/23 (78%) |
|FIRST INCIDENCE (DAYS) |   242          490          499          444       |   454          488          468          425       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.160      P=0.380N     P=0.228N     P=0.162    |  P=0.104      P=0.044 *    P=0.286      P=0.062    |
|INCIDENTAL TUMOR       |  P=0.421      P=0.555N     P=0.141N     P=0.308    |  P=0.070      P=0.317      P=0.098      P=0.107    |
|LOGISTIC REGRESSION    |  P=0.464      P=0.511      P=0.132N     P=0.424    |  P=0.056      P=0.262      P=0.126      P=0.094    |
|COCHRAN-ARMITAGE       |  P=0.446                                           |  P=0.063                                           |
|FISHER EXACT           |               P=0.568      P=0.138N     P=0.426    |               P=0.333      P=0.133      P=0.088    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  14
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 38/50 (76%)  36/47 (77%)  32/50 (64%)  39/49 (80%) | 33/50 (66%)  36/50 (72%)  40/50 (80%)  40/50 (80%) |
|ADJUSTED (b)           | 100.0%        97.1%        84.6%        97.1%      |  74.2%        91.8%        90.8%        88.5%      |
|TERMINAL (d)           | 13/13 (100%) 15/16 (94%)   9/14 (64%)   7/8 (88%)  | 17/28 (61%)  16/19 (84%)  26/30 (87%)  18/23 (78%) |
|FIRST INCIDENCE (DAYS) |   242          490          499          444       |   454          488          468          425       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.160      P=0.380N     P=0.228N     P=0.162    |  P=0.100      P=0.044 *    P=0.236      P=0.062    |
|INCIDENTAL TUMOR       |  P=0.421      P=0.555N     P=0.141N     P=0.308    |  P=0.065      P=0.317      P=0.064      P=0.107    |
|LOGISTIC REGRESSION    |  P=0.464      P=0.511      P=0.132N     P=0.424    |  P=0.051      P=0.262      P=0.082      P=0.094    |
|COCHRAN-ARMITAGE       |  P=0.446                                           |  P=0.059                                           |
|FISHER EXACT           |               P=0.568      P=0.138N     P=0.426    |               P=0.333      P=0.088      P=0.088    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Intermedia                                                                                                 |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/47 (0%)    1/50 (2%)    2/49 (4%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         7.1%         8.1%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          733 (T)      636       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.053        (e)        P=0.515      P=0.233    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.072        (e)        P=0.515      P=0.274    |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.065        (e)        P=0.515      P=0.230    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.070                                           |    (e)                                             |
|FISHER EXACT           |                 (e)        P=0.500      P=0.242    |                 (e)          (e)          (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  15
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Carcinoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         9.1%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          480       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.037 *      (e)          (e)        P=0.199    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.064        (e)          (e)        P=0.271    |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.042 *      (e)          (e)        P=0.228    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.046 *                                         |    (e)                                             |
|FISHER EXACT           |                 (e)          (e)        P=0.247    |                 (e)          (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|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)            |  7/50 (14%)   4/50 (8%)    3/50 (6%)    7/50 (14%) |  1/50 (2%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |
|ADJUSTED (b)           |  44.7%        22.0%        12.8%        40.9%      |   2.3%         5.3%         3.3%         4.3%      |
|TERMINAL (d)           |  5/13 (38%)   3/16 (19%)   1/14 (7%)    2/8 (25%)  |  0/28 (0%)    1/19 (5%)    1/30 (3%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   673          650          608          480       |   573          733 (T)      733 (T)      733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.277      P=0.185N     P=0.143N     P=0.352    |  P=0.619      P=0.710      P=0.758N     P=0.739    |
|INCIDENTAL TUMOR       |  P=0.416      P=0.223N     P=0.133N     P=0.523    |  P=0.624      P=0.763N     P=0.633      P=0.749N   |
|LOGISTIC REGRESSION    |  P=0.438      P=0.305N     P=0.167N     P=0.543    |  P=0.630      P=0.752N     P=0.756N     P=0.753N   |
|COCHRAN-ARMITAGE       |  P=0.485                                           |  P=0.633                                           |
|FISHER EXACT           |               P=0.262N     P=0.159N     P=0.613N   |               P=0.753N     P=0.753N     P=0.753N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  16
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  13.9%         0.0%         4.5%         0.0%      |   2.9%         5.3%         0.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    1/19 (5%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   623          ---          678          ---       |   691          733 (T)      ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.098N     P=0.126N     P=0.311N     P=0.158N   |  P=0.251N     P=0.681      P=0.500N     P=0.546N   |
|INCIDENTAL TUMOR       |  P=0.075N     P=0.134N     P=0.308N     P=0.128N   |  P=0.225N     P=0.753      P=0.479N     P=0.443N   |
|LOGISTIC REGRESSION    |  P=0.087N     P=0.128N     P=0.305N     P=0.125N   |  P=0.240N     P=0.720      P=0.501N     P=0.506N   |
|COCHRAN-ARMITAGE       |  P=0.086N                                          |  P=0.235N                                          |
|FISHER EXACT           |               P=0.121N     P=0.309N     P=0.121N   |               P=0.753N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  6/50 (12%)   0/50 (0%)    2/50 (4%)    0/50 (0%)  |  1/50 (2%)    3/50 (6%)    0/50 (0%)    3/50 (6%)  |
|ADJUSTED (b)           |  30.6%         0.0%        10.9%         0.0%      |   2.9%        11.5%         0.0%        10.0%      |
|TERMINAL (d)           |  3/13 (23%)   0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    1/19 (5%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   623          ---          678          ---       |   691          579          ---          387       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.022N*    P=0.016N*    P=0.137N     P=0.037N*  |  P=0.306      P=0.221      P=0.500N     P=0.256    |
|INCIDENTAL TUMOR       |  P=0.013N*    P=0.016N*    P=0.129N     P=0.027N*  |  P=0.344      P=0.358      P=0.479N     P=0.319    |
|LOGISTIC REGRESSION    |  P=0.015N*    P=0.020N*    P=0.137N     P=0.020N*  |  P=0.329      P=0.292      P=0.501N     P=0.339    |
|COCHRAN-ARMITAGE       |  P=0.014N*                                         |  P=0.325                                           |
|FISHER EXACT           |               P=0.013N*    P=0.134N     P=0.013N*  |               P=0.309      P=0.500N     P=0.309    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  17
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  0/50 (0%)    1/50 (2%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |  18.2%         0.0%         0.0%         0.0%      |   0.0%         2.5%         0.0%         4.0%      |
|TERMINAL (d)           |  2/13 (15%)   0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   644          ---          ---          ---       |   ---          579          ---          720       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.058N     P=0.105N     P=0.118N     P=0.186N   |  P=0.401      P=0.486        (e)        P=0.464    |
|INCIDENTAL TUMOR       |  P=0.052N     P=0.098N     P=0.102N     P=0.175N   |  P=0.442      P=0.581        (e)        P=0.557    |
|LOGISTIC REGRESSION    |  P=0.051N     P=0.133N     P=0.125N     P=0.142N   |  P=0.407      P=0.580        (e)        P=0.476    |
|COCHRAN-ARMITAGE       |  P=0.047N*                                         |  P=0.405                                           |
|FISHER EXACT           |               P=0.121N     P=0.121N     P=0.121N   |               P=0.500        (e)        P=0.500    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma, Sarcoma, Myxosarcoma, or Fibrous Histiocytoma                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    0/50 (0%)    2/50 (4%)    0/50 (0%)  |  0/50 (0%)    2/50 (4%)    0/50 (0%)    3/50 (6%)  |
|ADJUSTED (b)           |  18.2%         0.0%        10.9%         0.0%      |   0.0%         6.6%         0.0%        10.0%      |
|TERMINAL (d)           |  2/13 (15%)   0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   644          ---          678          ---       |   ---          579          ---          387       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.168N     P=0.105N     P=0.494N     P=0.186N   |  P=0.094      P=0.201        (e)        P=0.102    |
|INCIDENTAL TUMOR       |  P=0.122N     P=0.098N     P=0.495N     P=0.175N   |  P=0.104      P=0.319        (e)        P=0.115    |
|LOGISTIC REGRESSION    |  P=0.141N     P=0.133N     P=0.517N     P=0.142N   |  P=0.099      P=0.261        (e)        P=0.143    |
|COCHRAN-ARMITAGE       |  P=0.125N                                          |  P=0.097                                           |
|FISHER EXACT           |               P=0.121N     P=0.500N     P=0.121N   |               P=0.247        (e)        P=0.121    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  18
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Keratoacanthoma                                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  6/50 (12%)   2/50 (4%)    2/50 (4%)    2/50 (4%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  41.0%        10.0%        10.5%        16.3%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  5/13 (38%)   1/16 (6%)    1/14 (7%)    1/8 (13%)  |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   673          650          643          675       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.191N     P=0.092N     P=0.113N     P=0.268N   |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.153N     P=0.107N     P=0.107N     P=0.227N   |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.143N     P=0.155N     P=0.146N     P=0.220N   |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.113N                                          |    (e)                                             |
|FISHER EXACT           |               P=0.134N     P=0.134N     P=0.134N   |                 (e)          (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Sarcoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    2/50 (4%)    0/50 (0%)  |  0/50 (0%)    1/50 (2%)    0/50 (0%)    2/50 (4%)  |
|ADJUSTED (b)           |   0.0%         0.0%        10.9%         0.0%      |   0.0%         4.2%         0.0%         6.3%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          678          ---       |   ---          698          ---          387       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.553        (e)        P=0.242        (e)      |  P=0.133      P=0.443        (e)        P=0.218    |
|INCIDENTAL TUMOR       |  P=0.670        (e)        P=0.205        (e)      |  P=0.126      P=0.557        (e)        P=0.195    |
|LOGISTIC REGRESSION    |  P=0.571        (e)        P=0.228        (e)      |  P=0.144      P=0.474        (e)        P=0.303    |
|COCHRAN-ARMITAGE       |  P=0.593                                           |  P=0.140                                           |
|FISHER EXACT           |                 (e)        P=0.247        (e)      |               P=0.500        (e)        P=0.247    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  19
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Schwannoma Malignant                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |  0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%        14.5%      |   0.0%         0.0%         3.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    1/8 (13%)  |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          544       |   ---          ---          698          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.030 *      (e)          (e)        P=0.192    |  P=0.683        (e)        P=0.506        (e)      |
|INCIDENTAL TUMOR       |  P=0.026 *      (e)          (e)        P=0.187    |  P=0.717        (e)        P=0.521        (e)      |
|LOGISTIC REGRESSION    |  P=0.046 *      (e)          (e)        P=0.238    |  P=0.691        (e)        P=0.499        (e)      |
|COCHRAN-ARMITAGE       |  P=0.046 *                                         |  P=0.693                                           |
|FISHER EXACT           |                 (e)          (e)        P=0.247    |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Carcinoma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    1/50 (2%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   6.3%        12.5%         2.6%        12.5%      |   0.0%         0.0%         3.3%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    2/16 (13%)   0/14 (0%)    1/8 (13%)  |  0/28 (0%)    0/19 (0%)    1/30 (3%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   725          733 (T)      608          733 (T)   |   ---          ---          733 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.596      P=0.548      P=0.758N     P=0.638    |  P=0.685        (e)        P=0.514        (e)      |
|INCIDENTAL TUMOR       |  P=0.593N     P=0.502      P=0.755N     P=0.743    |  P=0.685        (e)        P=0.514        (e)      |
|LOGISTIC REGRESSION    |  P=0.575N     P=0.486      P=0.762N     P=0.661    |  P=0.685        (e)        P=0.514        (e)      |
|COCHRAN-ARMITAGE       |  P=0.530N                                          |  P=0.693                                           |
|FISHER EXACT           |               P=0.500      P=0.753N     P=0.753N   |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  20
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Carcinoma, Basal Cell Carcinoma, Basosquamous Tumor                                                           |
|     (malignant or NOS), or Carcinoma                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    1/50 (2%)    3/50 (6%)  |  0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   6.3%        12.5%         2.6%        20.5%      |   0.0%         0.0%         3.3%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    2/16 (13%)   0/14 (0%)    1/8 (13%)  |  0/28 (0%)    0/19 (0%)    1/30 (3%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   725          733 (T)      608          480       |   ---          ---          733 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.138      P=0.548      P=0.758N     P=0.192    |  P=0.685        (e)        P=0.514        (e)      |
|INCIDENTAL TUMOR       |  P=0.210      P=0.502      P=0.755N     P=0.314    |  P=0.685        (e)        P=0.514        (e)      |
|LOGISTIC REGRESSION    |  P=0.231      P=0.486      P=0.762N     P=0.300    |  P=0.685        (e)        P=0.514        (e)      |
|COCHRAN-ARMITAGE       |  P=0.237                                           |  P=0.693                                           |
|FISHER EXACT           |               P=0.500      P=0.753N     P=0.309    |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    3/50 (6%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%        13.3%      |   2.3%         5.3%         0.0%         4.3%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    1/19 (5%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          660       |   573          733 (T)      ---          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.012 *      (e)          (e)        P=0.109    |  P=0.625N     P=0.710      P=0.509N     P=0.739    |
|INCIDENTAL TUMOR       |  P=0.034 *      (e)          (e)        P=0.172    |  P=0.613N     P=0.763N     P=0.773N     P=0.749N   |
|LOGISTIC REGRESSION    |  P=0.011 *      (e)          (e)        P=0.113    |  P=0.616N     P=0.752N     P=0.448N     P=0.753N   |
|COCHRAN-ARMITAGE       |  P=0.012 *                                         |  P=0.615N                                          |
|FISHER EXACT           |                 (e)          (e)        P=0.121    |               P=0.753N     P=0.500N     P=0.753N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  21
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, Squamous Cell Carcinoma or Keratoacanthoma                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  7/50 (14%)   4/50 (8%)    3/50 (6%)    5/50 (10%) |  1/50 (2%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |
|ADJUSTED (b)           |  44.7%        22.0%        12.8%        35.0%      |   2.3%         5.3%         3.3%         4.3%      |
|TERMINAL (d)           |  5/13 (38%)   3/16 (19%)   1/14 (7%)    2/8 (25%)  |  0/28 (0%)    1/19 (5%)    1/30 (3%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   673          650          608          660       |   573          733 (T)      733 (T)      733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.563N     P=0.185N     P=0.143N     P=0.614    |  P=0.619      P=0.710      P=0.758N     P=0.739    |
|INCIDENTAL TUMOR       |  P=0.431N     P=0.223N     P=0.133N     P=0.494N   |  P=0.624      P=0.763N     P=0.633      P=0.749N   |
|LOGISTIC REGRESSION    |  P=0.427N     P=0.305N     P=0.167N     P=0.529N   |  P=0.630      P=0.752N     P=0.756N     P=0.753N   |
|COCHRAN-ARMITAGE       |  P=0.356N                                          |  P=0.633                                           |
|FISHER EXACT           |               P=0.262N     P=0.159N     P=0.380N   |               P=0.753N     P=0.753N     P=0.753N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, or Keratoacanthoma                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  6/50 (12%)   2/50 (4%)    2/50 (4%)    4/50 (8%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |  41.0%        10.0%        10.5%        24.1%      |   2.3%         5.3%         0.0%         4.3%      |
|TERMINAL (d)           |  5/13 (38%)   1/16 (6%)    1/14 (7%)    1/8 (13%)  |  0/28 (0%)    1/19 (5%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   673          650          643          660       |   573          733 (T)      ---          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.550N     P=0.092N     P=0.113N     P=0.581N   |  P=0.625N     P=0.710      P=0.509N     P=0.739    |
|INCIDENTAL TUMOR       |  P=0.442N     P=0.107N     P=0.107N     P=0.480N   |  P=0.613N     P=0.763N     P=0.773N     P=0.749N   |
|LOGISTIC REGRESSION    |  P=0.450N     P=0.155N     P=0.146N     P=0.484N   |  P=0.616N     P=0.752N     P=0.448N     P=0.753N   |
|COCHRAN-ARMITAGE       |  P=0.388N                                          |  P=0.615N                                          |
|FISHER EXACT           |               P=0.134N     P=0.134N     P=0.370N   |               P=0.753N     P=0.500N     P=0.753N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  22
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Testes                                                                                                                           |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 38/50 (76%)  34/50 (68%)  40/50 (80%)  31/50 (62%) |                                                    |
|ADJUSTED (b)           | 100.0%        91.1%       100.0%       100.0%      |                                                    |
|TERMINAL (d)           | 13/13 (100%) 13/16 (81%)  14/14 (100%)  8/8 (100%) |                                                    |
|FIRST INCIDENCE (DAYS) |   490          427          395          480       |                                                    |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.418      P=0.293N     P=0.458      P=0.455    |                                                    |
|INCIDENTAL TUMOR       |  P=0.096N     P=0.283N     P=0.467      P=0.091N   |                                                    |
|LOGISTIC REGRESSION    |  P=0.080N     P=0.325N     P=0.454      P=0.073N   |                                                    |
|COCHRAN-ARMITAGE       |  P=0.117N                                          |                                                    |
|FISHER EXACT           |               P=0.252N     P=0.405      P=0.097N   |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  8/50 (16%)   5/50 (10%)   8/50 (16%)   8/50 (16%) |  8/50 (16%)   9/50 (18%)   8/50 (16%)  10/49 (20%) |
|ADJUSTED (b)           |  30.6%        24.7%        42.6%        50.9%      |  25.3%        33.8%        24.5%        34.2%      |
|TERMINAL (d)           |  1/13 (8%)    3/16 (19%)   5/14 (36%)   3/8 (38%)  |  6/28 (21%)   4/19 (21%)   6/30 (20%)   5/22 (23%) |
|FIRST INCIDENCE (DAYS) |   504          574          560          617       |   600          561          657          634       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.237      P=0.280N     P=0.598N     P=0.404    |  P=0.304      P=0.252      P=0.557N     P=0.260    |
|INCIDENTAL TUMOR       |  P=0.399      P=0.304N     P=0.570N     P=0.588N   |  P=0.365      P=0.426      P=0.536      P=0.369    |
|LOGISTIC REGRESSION    |  P=0.407      P=0.300N     P=0.608      P=0.586    |  P=0.322      P=0.399      P=0.608      P=0.320    |
|COCHRAN-ARMITAGE       |  P=0.433                                           |  P=0.346                                           |
|FISHER EXACT           |               P=0.277N     P=0.607N     P=0.607N   |               P=0.500      P=0.607N     P=0.379    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  23
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    2/50 (4%)    1/50 (2%)    3/50 (6%)  |  2/50 (4%)    0/50 (0%)    0/50 (0%)    3/49 (6%)  |
|ADJUSTED (b)           |   0.0%        10.0%         6.7%        14.2%      |   7.1%         0.0%         0.0%        11.8%      |
|TERMINAL (d)           |  0/13 (0%)    1/16 (6%)    0/14 (0%)    0/8 (0%)   |  2/28 (7%)    0/19 (0%)    0/30 (0%)    2/22 (9%)  |
|FIRST INCIDENCE (DAYS) |   ---          650          728          607       |   733 (T)      ---          ---          660       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.071      P=0.249      P=0.514      P=0.101    |  P=0.220      P=0.327N     P=0.223N     P=0.410    |
|INCIDENTAL TUMOR       |  P=0.157      P=0.216      P=0.471      P=0.162    |  P=0.230      P=0.327N     P=0.223N     P=0.438    |
|LOGISTIC REGRESSION    |  P=0.096      P=0.222      P=0.482      P=0.117    |  P=0.225      P=0.327N     P=0.223N     P=0.434    |
|COCHRAN-ARMITAGE       |  P=0.104                                           |  P=0.240                                           |
|FISHER EXACT           |               P=0.247      P=0.500      P=0.121    |               P=0.247N     P=0.247N     P=0.490    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  8/50 (16%)   7/50 (14%)   9/50 (18%)  11/50 (22%) | 10/50 (20%)   9/50 (18%)   8/50 (16%)  12/49 (24%) |
|ADJUSTED (b)           |  30.6%        33.3%        46.4%        57.8%      |  32.1%        33.8%        24.5%        42.0%      |
|TERMINAL (d)           |  1/13 (8%)    4/16 (25%)   5/14 (36%)   3/8 (38%)  |  8/28 (29%)   4/19 (21%)   6/30 (20%)   7/22 (32%) |
|FIRST INCIDENCE (DAYS) |   504          574          560          607       |   600          561          657          634       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.079      P=0.488N     P=0.508      P=0.164    |  P=0.260      P=0.406      P=0.345N     P=0.235    |
|INCIDENTAL TUMOR       |  P=0.200      P=0.540N     P=0.529      P=0.351    |  P=0.314      P=0.596      P=0.458N     P=0.333    |
|LOGISTIC REGRESSION    |  P=0.174      P=0.536N     P=0.498      P=0.282    |  P=0.278      P=0.581      P=0.394N     P=0.301    |
|COCHRAN-ARMITAGE       |  P=0.198                                           |  P=0.306                                           |
|FISHER EXACT           |               P=0.500N     P=0.500      P=0.306    |               P=0.500N     P=0.398N     P=0.384    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  24
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    2/50 (4%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/49 (0%)  |
|ADJUSTED (b)           |   2.6%         2.4%        12.9%         0.0%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/22 (0%)  |
|FIRST INCIDENCE (DAYS) |   590          523          720          ---       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.437N     P=0.749      P=0.498      P=0.495N   |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.369N     P=0.733N     P=0.514      P=0.486N   |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.367N     P=0.752N     P=0.498      P=0.508N   |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.367N                                          |    (e)                                             |
|FISHER EXACT           |               P=0.753N     P=0.500      P=0.500N   |                 (e)          (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    2/50 (4%)    0/50 (0%)  |  0/50 (0%)    1/50 (2%)    0/50 (0%)    0/49 (0%)  |
|ADJUSTED (b)           |   2.6%         8.5%        12.9%         0.0%      |   0.0%         3.4%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    1/16 (6%)    1/14 (7%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/22 (0%)  |
|FIRST INCIDENCE (DAYS) |   590          523          720          ---       |   ---          665          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.381N     P=0.512      P=0.498      P=0.495N   |  P=0.566N     P=0.462        (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.323N     P=0.553      P=0.514      P=0.486N   |  P=0.537N     P=0.557        (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.297N     P=0.507      P=0.498      P=0.508N   |  P=0.569N     P=0.503        (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.296N                                          |  P=0.570N                                          |
|FISHER EXACT           |               P=0.500      P=0.500      P=0.500N   |               P=0.500        (e)          (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  25
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Urinary Bladder                                                                                                                  |
|     Carcinoma or Papilloma                                                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    2/49 (4%)    1/50 (2%)  |
|ADJUSTED (b)           |   0.0%         3.1%         0.0%         0.0%      |   0.0%         0.0%         6.7%         3.4%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    2/30 (7%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          607          ---          ---       |   ---          ---          733 (T)      676       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.552N     P=0.482        (e)          (e)      |  P=0.228        (e)        P=0.253      P=0.462    |
|INCIDENTAL TUMOR       |  P=0.554N     P=0.500        (e)          (e)      |  P=0.248        (e)        P=0.253      P=0.557    |
|LOGISTIC REGRESSION    |  P=0.572N     P=0.506        (e)          (e)      |  P=0.238        (e)        P=0.253      P=0.500    |
|COCHRAN-ARMITAGE       |  P=0.567N                                          |  P=0.245                                           |
|FISHER EXACT           |               P=0.500        (e)          (e)      |                 (e)        P=0.242      P=0.500    |
|=================================================================================================================================|
|                                                                                                                                 |
|Urinary Bladder                                                                                                                  |
|     Papilloma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    2/49 (4%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         3.1%         0.0%         0.0%      |   0.0%         0.0%         6.7%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    2/30 (7%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          607          ---          ---       |   ---          ---          733 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.552N     P=0.482        (e)          (e)      |  P=0.579        (e)        P=0.253        (e)      |
|INCIDENTAL TUMOR       |  P=0.554N     P=0.500        (e)          (e)      |  P=0.579        (e)        P=0.253        (e)      |
|LOGISTIC REGRESSION    |  P=0.572N     P=0.506        (e)          (e)      |  P=0.579        (e)        P=0.253        (e)      |
|COCHRAN-ARMITAGE       |  P=0.567N                                          |  P=0.593                                           |
|FISHER EXACT           |               P=0.500        (e)          (e)      |                 (e)        P=0.242        (e)      |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  26
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Polyp Stromal                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  6/50 (12%)  11/50 (22%)   6/50 (12%)   6/50 (12%) |
|ADJUSTED (b)           |                                                    |  19.8%        37.6%        18.3%        22.7%      |
|TERMINAL (d)           |                                                    |  4/28 (14%)   4/19 (21%)   5/30 (17%)   4/23 (17%) |
|FIRST INCIDENCE (DAYS) |                                                    |   713          428          432          651       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.409N     P=0.049 *    P=0.585N     P=0.485    |
|INCIDENTAL TUMOR       |                                                    |  P=0.357N     P=0.131      P=0.543N     P=0.598    |
|LOGISTIC REGRESSION    |                                                    |  P=0.362N     P=0.112      P=0.619      P=0.530    |
|COCHRAN-ARMITAGE       |                                                    |  P=0.354N                                          |
|FISHER EXACT           |                                                    |               P=0.143      P=0.620N     P=0.620N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Sarcoma Stromal or Polyp Stromal                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  6/50 (12%)  12/50 (24%)   6/50 (12%)   6/50 (12%) |
|ADJUSTED (b)           |                                                    |  19.8%        38.9%        18.3%        22.7%      |
|TERMINAL (d)           |                                                    |  4/28 (14%)   4/19 (21%)   5/30 (17%)   4/23 (17%) |
|FIRST INCIDENCE (DAYS) |                                                    |   713          428          432          651       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.374N     P=0.032 *    P=0.585N     P=0.485    |
|INCIDENTAL TUMOR       |                                                    |  P=0.328N     P=0.094      P=0.543N     P=0.598    |
|LOGISTIC REGRESSION    |                                                    |  P=0.298N     P=0.090      P=0.619      P=0.530    |
|COCHRAN-ARMITAGE       |                                                    |  P=0.320N                                          |
|FISHER EXACT           |                                                    |               P=0.096      P=0.620N     P=0.620N   |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  27
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Zymbal's Gland                                                                                                                   |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    2/50 (4%)    0/50 (0%)    1/50 (2%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |   0.0%         4.1%         0.0%         2.6%      |   3.6%         5.3%         0.0%         4.3%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  1/28 (4%)    1/19 (5%)    0/30 (0%)    1/23 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          397          ---          595       |   733 (T)      733 (T)      ---          733 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.548      P=0.240        (e)        P=0.511    |  P=0.635N     P=0.673      P=0.486N     P=0.718    |
|INCIDENTAL TUMOR       |  P=0.528      P=0.290        (e)        P=0.514    |  P=0.635N     P=0.673      P=0.486N     P=0.718    |
|LOGISTIC REGRESSION    |  P=0.409      P=0.214        (e)        P=0.494    |  P=0.635N     P=0.673      P=0.486N     P=0.718    |
|COCHRAN-ARMITAGE       |  P=0.539                                           |  P=0.615N                                          |
|FISHER EXACT           |               P=0.247        (e)        P=0.500    |               P=0.753N     P=0.500N     P=0.753N   |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 35/50 (70%)  27/50 (54%)  33/50 (66%)  25/50 (50%) | 22/50 (44%)  13/50 (26%)  14/50 (28%)   9/50 (18%) |
|ADJUSTED (b)           |  88.2%        92.1%        80.3%        90.0%      |  52.5%        38.1%        37.6%        27.2%      |
|TERMINAL (d)           |  9/13 (69%)  14/16 (88%)   7/14 (50%)   6/8 (75%)  |  9/28 (32%)   3/19 (16%)   8/30 (27%)   3/23 (13%) |
|FIRST INCIDENCE (DAYS) |   411          427          499          405       |   519          428          512          597       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.388N     P=0.119N     P=0.441N     P=0.357N   |  P=0.020N*    P=0.268N     P=0.089N     P=0.030N*  |
|INCIDENTAL TUMOR       |  P=0.044N*    P=0.071N     P=0.370N     P=0.029N*  |  P=0.004N**   P=0.017N*    P=0.130N     P=0.002N** |
|LOGISTIC REGRESSION    |  P=0.053N     P=0.091N     P=0.410N     P=0.033N*  |  P=0.005N**   P=0.033N*    P=0.124N     P=0.001N** |
|COCHRAN-ARMITAGE       |  P=0.059N                                          |  P=0.007N**                                        |
|FISHER EXACT           |               P=0.074N     P=0.415N     P=0.033N*  |               P=0.046N*    P=0.072N     P=0.004N** |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  28
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Mesothelioma: Benign, Malignant, NOS                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    3/50 (6%)    0/50 (0%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   2.1%         8.1%         0.0%         9.1%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/16 (0%)    0/14 (0%)    0/8 (0%)   |  0/28 (0%)    0/19 (0%)    0/30 (0%)    0/23 (0%)  |
|FIRST INCIDENCE (DAYS) |   490          439          ---          709       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.435N     P=0.297      P=0.500N     P=0.696    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.383N     P=0.350      P=0.531N     P=0.729N   |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.441N     P=0.324      P=0.588N     P=0.759    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.409N                                          |    (e)                                             |
|FISHER EXACT           |               P=0.309      P=0.500N     P=0.753N   |                 (e)          (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Benign Tumors                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 50/50 (100%) 45/50 (90%)  50/50 (100%) 47/50 (94%) | 44/50 (88%)  47/50 (94%)  48/50 (96%)  49/50 (98%) |
|ADJUSTED (b)           | 100.0%       100.0%       100.0%       100.0%      |  97.7%       100.0%       100.0%       100.0%      |
|TERMINAL (d)           | 13/13 (100%) 16/16 (100%) 14/14 (100%)  8/8 (100%) | 27/28 (96%)  19/19 (100%) 30/30 (100%) 23/23 (100%)|
|FIRST INCIDENCE (DAYS) |   242          427          395          444       |   454          428          432          425       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.229      P=0.293N     P=0.530N     P=0.278    |  P=0.162      P=0.015 *    P=0.425      P=0.058    |
|INCIDENTAL TUMOR       |  P=0.145N     P=0.043N*      (e)        P=0.105N   |  P=0.029 *    P=0.134      P=0.102      P=0.045 *  |
|LOGISTIC REGRESSION    |  P=0.139N     P=0.023N*      (e)        P=0.045N*  |  P=0.021 *    P=0.161      P=0.094      P=0.036 *  |
|COCHRAN-ARMITAGE       |  P=0.313N                                          |  P=0.035 *                                         |
|FISHER EXACT           |               P=0.028N*    P=1.000N     P=0.121N   |               P=0.243      P=0.134      P=0.056    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  29
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      94 PPM       188 PPM      375 PPM   |   CONTROL      94 PPM       188 PPM      375 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Tumors                                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 40/50 (80%)  35/50 (70%)  39/50 (78%)  33/50 (66%) | 28/50 (56%)  21/50 (42%)  20/50 (40%)  27/50 (54%) |
|ADJUSTED (b)           |  92.4%        96.9%        89.6%        96.2%      |  63.0%        56.5%        49.8%        65.0%      |
|TERMINAL (d)           | 10/13 (77%)  15/16 (94%)  10/14 (71%)   7/8 (88%)  | 12/28 (43%)   6/19 (32%)  11/30 (37%)  10/23 (43%) |
|FIRST INCIDENCE (DAYS) |   411          292          395          405       |   519          428          432          387       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.475      P=0.258N     P=0.489N     P=0.529    |  P=0.435      P=0.518N     P=0.108N     P=0.412    |
|INCIDENTAL TUMOR       |  P=0.110N     P=0.181N     P=0.434N     P=0.065N   |  P=0.537N     P=0.054N     P=0.124N     P=0.380N   |
|LOGISTIC REGRESSION    |  P=0.107N     P=0.197N     P=0.499N     P=0.087N   |  P=0.513      P=0.086N     P=0.078N     P=0.455N   |
|COCHRAN-ARMITAGE       |  P=0.112N                                          |  P=0.501                                           |
|FISHER EXACT           |               P=0.178N     P=0.500N     P=0.088N   |               P=0.115N     P=0.080N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant and Benign Tumors                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 50/50 (100%) 49/50 (98%)  50/50 (100%) 49/50 (98%) | 49/50 (98%)  50/50 (100%) 50/50 (100%) 50/50 (100%)|
|ADJUSTED (b)           | 100.0%       100.0%       100.0%       100.0%      |  98.0%       100.0%       100.0%       100.0%      |
|TERMINAL (d)           | 13/13 (100%) 16/16 (100%) 14/14 (100%)  8/8 (100%) | 27/28 (96%)  19/19 (100%) 30/30 (100%) 23/23 (100%)|
|FIRST INCIDENCE (DAYS) |   242          292          395          405       |   454          428          432          387       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.210      P=0.481N     P=0.530N     P=0.210    |  P=0.347      P=0.034 *    P=0.513N     P=0.170    |
|INCIDENTAL TUMOR       |  P=0.380N     P=0.550N       (e)        P=0.500N   |  P=0.313      P=0.577      P=0.486      P=0.539    |
|LOGISTIC REGRESSION    |  P=0.340N     P=0.510N       (e)        P=0.455N   |  P=0.313      P=0.577      P=0.486      P=0.539    |
|COCHRAN-ARMITAGE       |  P=0.405N                                          |  P=0.304                                           |
|FISHER EXACT           |               P=0.500N     P=1.000N     P=0.500N   |               P=0.500      P=0.500      P=0.500    |
|=================================================================================================================================|
         DATE: 04/04/96                     EXPERIMENT: 05200 TEST: 05                                                 PAGE  30
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- NITROMETHANE

                                                 TERMINAL SACRIFICE AT 105 WEEKS
                                                                           

 (a)  Number of tumor-bearing animals / number of animals examined at site.
 (b)  Kaplan-Meier estimated lifetime tumor incidence after adjustment for 
      intercurrent mortality.
 (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).