National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/5777

TDMS Study 89002-02 Pathology Tables

NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Columbus                                     PENTACHLOROPHENOL                                   DATE: 08/19/97       
EXPERIMENT: 89002 TEST: 02                                                                                     TIME: 16:58:33       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: NO1-ES-15322                              ROUTE: DOSED FEED                                              NTP C#: C89002       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 87-86-5         
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    
                                                       Control vs Stop Study                                                        
                                                                                                                                    

               REASONS FOR REMOVAL:    25019 Moribund Sacrifice                                                                     
                                       25020 Natural Death                                                                          
                                       25021 Terminal Sacrifice                                                                     
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       INCLUDE 001    0 PPM                                                                         
                                       INCLUDE 002    0 PPM                                                                         
                                       INCLUDE 009    1000 PPM                                                                      
                                       INCLUDE 010    1000 PPM                                                                      
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Columbus                                     PENTACHLOROPHENOL                                   DATE: 08/19/97       
EXPERIMENT: 89002 TEST: 02                                                                                     TIME: 16:58:33       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: NO1-ES-15322                              ROUTE: DOSED FEED                                              NTP C#: C89002       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 87-86-5         




                                                    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
                                                    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 Columbus                                     PENTACHLOROPHENOL                                   DATE: 08/19/97       
EXPERIMENT: 89002 TEST: 02                                                                                     TIME: 16:58:33       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: NO1-ES-15322                              ROUTE: DOSED FEED                                              NTP C#: C89002       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 87-86-5         




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

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

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

              Skin                          Keratoacanthoma
              Testes                        Adenoma
              All Organs                    Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                            Mesothelioma: Benign, Malignant, NOS
                                            Benign Tumors
                                            Malignant Tumors
                                            Malignant and Benign Tumors

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

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

              Mammary Gland                 Fibroadenoma
                                            Fibroma, Fibroadenoma, Carcinoma, or Adenoma

              ====================================================================================================
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   1
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Benign                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        14/50 (28%)         16/50 (32%)             |         0/50 (0%)           1/50 (2%)              |
|ADJUSTED (b)           |         57.3%               48.2%                  |          0.0%                3.6%                  |
|TERMINAL (d)           |         5/12 (42%)         10/27 (37%)             |         0/28 (0%)           1/28 (4%)              |
|FIRST INCIDENCE (DAYS) |          579                 684                   |          ---                 738 (T)               |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.142N               |                             P=0.500                |
|INCIDENTAL TUMOR       |                             P=0.553                |                             P=0.500                |
|LOGISTIC REGRESSION    |                             P=0.566N               |                             P=0.500                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.414                |                             P=0.500                |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Malignant                                                                                                  |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           3/50 (6%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          8.3%                9.9%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         1/12 (8%)           2/27 (7%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          736 (T)             680                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.563                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.478                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.424                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.309                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   2
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma: Benign, Complex, Malignant, NOS                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        16/50 (32%)         18/50 (36%)             |         0/50 (0%)           1/50 (2%)              |
|ADJUSTED (b)           |         65.3%               52.6%                  |          0.0%                3.6%                  |
|TERMINAL (d)           |         6/12 (50%)         11/27 (41%)             |         0/28 (0%)           1/28 (4%)              |
|FIRST INCIDENCE (DAYS) |          579                 680                   |          ---                 738 (T)               |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.106N               |                             P=0.500                |
|INCIDENTAL TUMOR       |                             P=0.575                |                             P=0.500                |
|LOGISTIC REGRESSION    |                             P=0.527N               |                             P=0.500                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.417                |                             P=0.500                |
|=================================================================================================================================|
|                                                                                                                                 |
|Brain                                                                                                                            |
|     Oligodendroglioma, Glioma, or Astrocytoma                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           2/50 (4%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%                4.1%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           0/27 (0%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 265                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.242                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.398                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.286                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.247                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   3
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         4/50 (8%)           4/49 (8%)              |         4/50 (8%)           5/49 (10%)             |
|ADJUSTED (b)           |         18.0%               11.5%                  |         13.0%               13.6%                  |
|TERMINAL (d)           |         1/12 (8%)           2/27 (7%)              |         3/28 (11%)          1/27 (4%)              |
|FIRST INCIDENCE (DAYS) |          647                 550                   |          645                 365                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.408N               |                             P=0.510                |
|INCIDENTAL TUMOR       |                             P=0.580                |                             P=0.587N               |
|LOGISTIC REGRESSION    |                             P=0.634                |                             P=0.488                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.631                |                             P=0.487                |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           2/49 (4%)              |         2/50 (4%)           1/49 (2%)              |
|ADJUSTED (b)           |          2.0%                5.8%                  |          6.8%                2.3%                  |
|TERMINAL (d)           |         0/12 (0%)           1/27 (4%)              |         1/28 (4%)           0/27 (0%)              |
|FIRST INCIDENCE (DAYS) |          396                 536                   |          715                 600                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.588                |                             P=0.489N               |
|INCIDENTAL TUMOR       |                             P=0.471                |                             P=0.477N               |
|LOGISTIC REGRESSION    |                             P=0.481                |                             P=0.507N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.492                |                             P=0.508N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   4
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         5/50 (10%)          5/49 (10%)             |         6/50 (12%)          6/49 (12%)             |
|ADJUSTED (b)           |         19.6%               13.4%                  |         19.3%               15.5%                  |
|TERMINAL (d)           |         1/12 (8%)           2/27 (7%)              |         4/28 (14%)          1/27 (4%)              |
|FIRST INCIDENCE (DAYS) |          396                 536                   |          645                 365                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.420N               |                             P=0.602N               |
|INCIDENTAL TUMOR       |                             P=0.503                |                             P=0.435N               |
|LOGISTIC REGRESSION    |                             P=0.581                |                             P=0.607                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.617                |                             P=0.606                |
|=================================================================================================================================|
|                                                                                                                                 |
|Intestine Small: Site Unspecified                                                                                                |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           2/50 (4%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%                6.1%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           1/27 (4%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 614                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.339                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.225                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.240                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.247                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   5
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           2/50 (4%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          4.2%                7.4%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           2/27 (7%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          695                 736 (T)               |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.722                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.625                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.617                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500                |                               (e)                  |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Adenoma                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           0/50 (0%)              |         2/50 (4%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%                0.0%                  |          6.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           0/27 (0%)              |         1/28 (4%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 ---                   |          645                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |           (e)                 (e)                  |                             P=0.232N               |
|INCIDENTAL TUMOR       |           (e)                 (e)                  |                             P=0.213N               |
|LOGISTIC REGRESSION    |           (e)                 (e)                  |                             P=0.236N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                               (e)                  |                             P=0.247N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   6
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           0/50 (0%)              |         3/50 (6%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%                0.0%                  |          9.5%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           0/27 (0%)              |         2/28 (7%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 ---                   |          645                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |           (e)                 (e)                  |                             P=0.118N               |
|INCIDENTAL TUMOR       |           (e)                 (e)                  |                             P=0.109N               |
|LOGISTIC REGRESSION    |           (e)                 (e)                  |                             P=0.115N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                               (e)                  |                             P=0.121N               |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroadenoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         5/50 (10%)          2/50 (4%)              |        25/50 (50%)         15/50 (30%)             |
|ADJUSTED (b)           |         21.8%                7.0%                  |         66.6%               45.8%                  |
|TERMINAL (d)           |         1/12 (8%)           1/27 (4%)              |        16/28 (57%)         11/28 (39%)             |
|FIRST INCIDENCE (DAYS) |          619                 715                   |          507                 600                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.081N               |                             P=0.036N*              |
|INCIDENTAL TUMOR       |                             P=0.287N               |                             P=0.031N*              |
|LOGISTIC REGRESSION    |                             P=0.175N               |                             P=0.022N*              |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.218N               |                             P=0.033N*              |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   7
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma, Carcinoma, or Adenoma                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         5/50 (10%)          2/50 (4%)              |        25/50 (50%)         15/50 (30%)             |
|ADJUSTED (b)           |         21.8%                7.0%                  |         66.6%               45.8%                  |
|TERMINAL (d)           |         1/12 (8%)           1/27 (4%)              |        16/28 (57%)         11/28 (39%)             |
|FIRST INCIDENCE (DAYS) |          619                 715                   |          507                 600                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.081N               |                             P=0.036N*              |
|INCIDENTAL TUMOR       |                             P=0.287N               |                             P=0.031N*              |
|LOGISTIC REGRESSION    |                             P=0.175N               |                             P=0.022N*              |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.218N               |                             P=0.033N*              |
|=================================================================================================================================|
|                                                                                                                                 |
|Nose                                                                                                                             |
|     Squamous Cell Carcinoma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           5/50 (10%)             |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          2.9%               14.0%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           2/27 (7%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          643                 460                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.210                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.062                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.093                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.102                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   8
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Papilloma Squamous or Papilloma                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           2/50 (4%)              |         2/50 (4%)           1/50 (2%)              |
|ADJUSTED (b)           |         12.7%                7.4%                  |          7.1%                3.4%                  |
|TERMINAL (d)           |         1/12 (8%)           2/27 (7%)              |         2/28 (7%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          702                 736 (T)               |          738 (T)             724                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.419N               |                             P=0.500N               |
|INCIDENTAL TUMOR       |                             P=0.522N               |                             P=0.472N               |
|LOGISTIC REGRESSION    |                             P=0.541N               |                             P=0.482N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.691N               |                             P=0.500N               |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma, Papilloma Squamous, or Papilloma                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           2/50 (4%)              |         2/50 (4%)           2/50 (4%)              |
|ADJUSTED (b)           |         12.7%                7.4%                  |          7.1%                6.1%                  |
|TERMINAL (d)           |         1/12 (8%)           2/27 (7%)              |         2/28 (7%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          702                 736 (T)               |          738 (T)             701                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.419N               |                             P=0.679N               |
|INCIDENTAL TUMOR       |                             P=0.522N               |                             P=0.651N               |
|LOGISTIC REGRESSION    |                             P=0.541N               |                             P=0.675N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.691N               |                             P=0.691N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE   9
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pancreas                                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           0/50 (0%)              |         0/50 (0%)           1/50 (2%)              |
|ADJUSTED (b)           |         11.3%                0.0%                  |          0.0%                3.6%                  |
|TERMINAL (d)           |         1/12 (8%)           0/27 (0%)              |         0/28 (0%)           1/28 (4%)              |
|FIRST INCIDENCE (DAYS) |          660                 ---                   |          ---                 738 (T)               |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.132N               |                             P=0.500                |
|INCIDENTAL TUMOR       |                             P=0.199N               |                             P=0.500                |
|LOGISTIC REGRESSION    |                             P=0.209N               |                             P=0.500                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.247N               |                             P=0.500                |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        18/50 (36%)         16/50 (32%)             |        22/50 (44%)         18/50 (36%)             |
|ADJUSTED (b)           |         56.3%               42.7%                  |         55.0%               53.6%                  |
|TERMINAL (d)           |         4/12 (33%)          7/27 (26%)             |        11/28 (39%)         13/28 (46%)             |
|FIRST INCIDENCE (DAYS) |          396                 565                   |          507                 652                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.082N               |                             P=0.262N               |
|INCIDENTAL TUMOR       |                             P=0.545                |                             P=0.245N               |
|LOGISTIC REGRESSION    |                             P=0.438N               |                             P=0.240N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.417N               |                             P=0.270N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  10
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Adenoma                                                                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           2/50 (4%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          3.7%                5.9%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           1/27 (4%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          684                 592                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.628                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.440                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.503                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500                |                               (e)                  |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Adenoma, Basosquamous Tumor Benign, or Trichoepithelioma                                                         |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           4/50 (8%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          3.7%               11.3%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           1/27 (4%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          684                 592                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.312                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.093                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.184                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.181                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  11
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Carcinoma, Basal Cell Adenoma, Basosquamous Tumor (benign,                                                       |
|     malignant or NOS), or Trichoepithelioma                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           4/50 (8%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          3.7%               11.3%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           1/27 (4%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          684                 592                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.312                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.093                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.184                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.181                |                               (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)            |         3/50 (6%)           9/50 (18%)             |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |         19.8%               26.7%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         2/12 (17%)          4/27 (15%)             |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          684                 592                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.297                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.078                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.102                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.061                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  12
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           1/50 (2%)              |         2/50 (4%)           0/50 (0%)              |
|ADJUSTED (b)           |          5.8%                2.4%                  |          5.7%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           0/27 (0%)              |         1/28 (4%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          603                 614                   |          523                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.447N               |                             P=0.240N               |
|INCIDENTAL TUMOR       |                             P=0.733                |                             P=0.366N               |
|LOGISTIC REGRESSION    |                             P=0.521N               |                             P=0.226N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500N               |                             P=0.247N               |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         5/50 (10%)          2/50 (4%)              |         3/50 (6%)           1/50 (2%)              |
|ADJUSTED (b)           |         24.7%                5.1%                  |          9.2%                2.1%                  |
|TERMINAL (d)           |         2/12 (17%)          0/27 (0%)              |         2/28 (7%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          603                 614                   |          523                 516                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.098N               |                             P=0.306N               |
|INCIDENTAL TUMOR       |                             P=0.304N               |                             P=0.525N               |
|LOGISTIC REGRESSION    |                             P=0.207N               |                             P=0.289N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.218N               |                             P=0.309N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  13
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           1/50 (2%)              |         1/50 (2%)           1/50 (2%)              |
|ADJUSTED (b)           |         16.7%                2.7%                  |          3.6%                2.1%                  |
|TERMINAL (d)           |         2/12 (17%)          0/27 (0%)              |         1/28 (4%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          736 (T)             680                   |          738 (T)             516                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.288N               |                             P=0.758N               |
|INCIDENTAL TUMOR       |                             P=0.375N               |                             P=0.634                |
|LOGISTIC REGRESSION    |                             P=0.405N               |                             P=0.755N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500N               |                             P=0.753N               |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma, Sarcoma, Myxosarcoma, or Fibrous Histiocytoma                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         3/50 (6%)           1/50 (2%)              |         1/50 (2%)           1/50 (2%)              |
|ADJUSTED (b)           |         20.1%                2.7%                  |          3.6%                2.1%                  |
|TERMINAL (d)           |         2/12 (17%)          0/27 (0%)              |         1/28 (4%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          695                 680                   |          738 (T)             516                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.135N               |                             P=0.758N               |
|INCIDENTAL TUMOR       |                             P=0.250N               |                             P=0.634                |
|LOGISTIC REGRESSION    |                             P=0.228N               |                             P=0.755N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.309N               |                             P=0.753N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  14
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Keratoacanthoma                                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           7/50 (14%)             |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%               23.1%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           4/27 (15%)             |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 708                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.061                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.015 *              |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.025 *              |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.006 **             |                               (e)                  |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           0/50 (0%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |         16.7%                0.0%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         2/12 (17%)          0/27 (0%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          736 (T)             ---                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.085N               |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.085N               |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.085N               |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.247N               |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  15
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, Squamous Cell Carcinoma or Keratoacanthoma                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           7/50 (14%)             |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |         16.7%               23.1%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         2/12 (17%)          4/27 (15%)             |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          736 (T)             708                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.353                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.177                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.208                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.080                |                               (e)                  |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, or Keratoacanthoma                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         2/50 (4%)           7/50 (14%)             |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |         16.7%               23.1%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         2/12 (17%)          4/27 (15%)             |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          736 (T)             708                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.353                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.177                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.208                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.080                |                               (e)                  |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  16
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Trichoepithelioma                                                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           2/50 (4%)              |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%                5.6%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           0/27 (0%)              |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 661                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.328                |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.130                |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.246                |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.247                |                               (e)                  |
|=================================================================================================================================|
|                                                                                                                                 |
|Testes                                                                                                                           |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        42/50 (84%)         45/50 (90%)             |                                                    |
|ADJUSTED (b)           |        100.0%              100.0%                  |                                                    |
|TERMINAL (d)           |        12/12 (100%)        27/27 (100%)            |                                                    |
|FIRST INCIDENCE (DAYS) |          561                 502                   |                                                    |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.004N**             |                                                    |
|INCIDENTAL TUMOR       |                             P=0.359                |                                                    |
|LOGISTIC REGRESSION    |                             P=0.410                |                                                    |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.277                |                                                    |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  17
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         5/50 (10%)          4/50 (8%)              |         3/50 (6%)           7/50 (14%)             |
|ADJUSTED (b)           |         19.4%               13.4%                  |          8.7%               21.2%                  |
|TERMINAL (d)           |         1/12 (8%)           3/27 (11%)             |         1/28 (4%)           4/28 (14%)             |
|FIRST INCIDENCE (DAYS) |          535                 675                   |          585                 668                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.235N               |                             P=0.186                |
|INCIDENTAL TUMOR       |                             P=0.479N               |                             P=0.202                |
|LOGISTIC REGRESSION    |                             P=0.471N               |                             P=0.166                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500N               |                             P=0.159                |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           0/50 (0%)              |         2/50 (4%)           1/50 (2%)              |
|ADJUSTED (b)           |          0.0%                0.0%                  |          7.1%                3.6%                  |
|TERMINAL (d)           |         0/12 (0%)           0/27 (0%)              |         2/28 (7%)           1/28 (4%)              |
|FIRST INCIDENCE (DAYS) |          ---                 ---                   |          738 (T)             738 (T)               |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |           (e)                 (e)                  |                             P=0.500N               |
|INCIDENTAL TUMOR       |           (e)                 (e)                  |                             P=0.500N               |
|LOGISTIC REGRESSION    |           (e)                 (e)                  |                             P=0.500N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                               (e)                  |                             P=0.500N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  18
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         5/50 (10%)          4/50 (8%)              |         5/50 (10%)          8/50 (16%)             |
|ADJUSTED (b)           |         19.4%               13.4%                  |         15.5%               24.5%                  |
|TERMINAL (d)           |         1/12 (8%)           3/27 (11%)             |         3/28 (11%)          5/28 (18%)             |
|FIRST INCIDENCE (DAYS) |          535                 675                   |          585                 668                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.235N               |                             P=0.304                |
|INCIDENTAL TUMOR       |                             P=0.479N               |                             P=0.327                |
|LOGISTIC REGRESSION    |                             P=0.471N               |                             P=0.298                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500N               |                             P=0.277                |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           2/50 (4%)              |         1/50 (2%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%                6.9%                  |          3.6%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           1/27 (4%)              |         1/28 (4%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 711                   |          738 (T)             ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.385                |                             P=0.500N               |
|INCIDENTAL TUMOR       |                             P=0.257                |                             P=0.500N               |
|LOGISTIC REGRESSION    |                             P=0.312                |                             P=0.500N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.247                |                             P=0.500N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  19
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         0/50 (0%)           3/50 (6%)              |         2/50 (4%)           0/50 (0%)              |
|ADJUSTED (b)           |          0.0%               10.5%                  |          7.1%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           2/27 (7%)              |         2/28 (7%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          ---                 711                   |          738 (T)             ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.267                |                             P=0.238N               |
|INCIDENTAL TUMOR       |                             P=0.178                |                             P=0.238N               |
|LOGISTIC REGRESSION    |                             P=0.197                |                             P=0.238N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.121                |                             P=0.247N               |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Polyp Stromal                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |         6/50 (12%)          6/50 (12%)             |
|ADJUSTED (b)           |                                                    |         21.4%               18.8%                  |
|TERMINAL (d)           |                                                    |         6/28 (21%)          4/28 (14%)             |
|FIRST INCIDENCE (DAYS) |                                                    |          738 (T)             600                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |                             P=0.611N               |
|INCIDENTAL TUMOR       |                                                    |                             P=0.608N               |
|LOGISTIC REGRESSION    |                                                    |                             P=0.581N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                                                    |                             P=0.620N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  20
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Sarcoma Stromal or Polyp Stromal                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |         6/50 (12%)          7/50 (14%)             |
|ADJUSTED (b)           |                                                    |         21.4%               20.9%                  |
|TERMINAL (d)           |                                                    |         6/28 (21%)          4/28 (14%)             |
|FIRST INCIDENCE (DAYS) |                                                    |          738 (T)             600                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |                             P=0.518                |
|INCIDENTAL TUMOR       |                                                    |                             P=0.529                |
|LOGISTIC REGRESSION    |                                                    |                             P=0.541                |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                                                    |                             P=0.500                |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        25/50 (50%)         15/50 (30%)             |        15/50 (30%)         11/50 (22%)             |
|ADJUSTED (b)           |         74.2%               42.4%                  |         37.8%               26.8%                  |
|TERMINAL (d)           |         5/12 (42%)          8/27 (30%)             |         5/28 (18%)          2/28 (7%)              |
|FIRST INCIDENCE (DAYS) |          561                 536                   |          475                 472                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.001N**             |                             P=0.231N               |
|INCIDENTAL TUMOR       |                             P=0.089N               |                             P=0.224N               |
|LOGISTIC REGRESSION    |                             P=0.018N*              |                             P=0.300N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.033N*              |                             P=0.247N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  21
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Mesothelioma: Benign, Malignant, NOS                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |         1/50 (2%)           9/50 (18%)             |         0/50 (0%)           0/50 (0%)              |
|ADJUSTED (b)           |          2.7%               24.9%                  |          0.0%                0.0%                  |
|TERMINAL (d)           |         0/12 (0%)           4/27 (15%)             |         0/28 (0%)           0/28 (0%)              |
|FIRST INCIDENCE (DAYS) |          617                 502                   |          ---                 ---                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.049 *              |           (e)                 (e)                  |
|INCIDENTAL TUMOR       |                             P=0.005 **             |           (e)                 (e)                  |
|LOGISTIC REGRESSION    |                             P=0.009 **             |           (e)                 (e)                  |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.008 **             |                               (e)                  |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Benign Tumors                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        48/50 (96%)         47/50 (94%)             |        37/50 (74%)         35/50 (70%)             |
|ADJUSTED (b)           |        100.0%              100.0%                  |         87.8%               85.2%                  |
|TERMINAL (d)           |        12/12 (100%)        27/27 (100%)            |        23/28 (82%)         22/28 (79%)             |
|FIRST INCIDENCE (DAYS) |          396                 502                   |          507                 365                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.001N**             |                             P=0.379N               |
|INCIDENTAL TUMOR       |                             P=0.702                |                             P=0.266N               |
|LOGISTIC REGRESSION    |                             P=0.401N               |                             P=0.352N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500N               |                             P=0.412N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  22
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |          0 PPM               1000 PPM              |          0 PPM               1000 PPM              |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Tumors                                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        32/50 (64%)         29/50 (58%)             |        20/50 (40%)         16/50 (32%)             |
|ADJUSTED (b)           |         84.3%               67.9%                  |         51.4%               36.2%                  |
|TERMINAL (d)           |         7/12 (58%)         14/27 (52%)             |        10/28 (36%)          3/28 (11%)             |
|FIRST INCIDENCE (DAYS) |          396                 265                   |          475                 472                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.013N*              |                             P=0.251N               |
|INCIDENTAL TUMOR       |                             P=0.508N               |                             P=0.273N               |
|LOGISTIC REGRESSION    |                             P=0.337N               |                             P=0.321N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.341N               |                             P=0.266N               |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant and Benign Tumors                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |           #                   #                    |           #                   #                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |        50/50 (100%)        49/50 (98%)             |        45/50 (90%)         42/50 (84%)             |
|ADJUSTED (b)           |        100.0%              100.0%                  |         95.7%               87.5%                  |
|TERMINAL (d)           |        12/12 (100%)        27/27 (100%)            |        26/28 (93%)         22/28 (79%)             |
|FIRST INCIDENCE (DAYS) |          396                 265                   |          475                 365                   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                             P=0.002N**             |                             P=0.315N               |
|INCIDENTAL TUMOR       |           (e)                 (e)                  |                             P=0.194N               |
|LOGISTIC REGRESSION    |                             P=0.680N               |                             P=0.284N               |
|COCHRAN-ARMITAGE       |                                                    |                                                    |
|FISHER EXACT           |                             P=0.500N               |                             P=0.277N               |
|=================================================================================================================================|
         DATE: 08/19/97                     EXPERIMENT: 89002 TEST: 02                                                 PAGE  23
                            STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- PENTACHLOROPHENOL

                                                 TERMINAL SACRIFICE AT 106 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).
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.