NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08
LAB: TSI Mason Research                                         PYRIDINE                                       DATE: 09/26/97

EXPERIMENT: 55301 TEST: 06                                                                                     TIME: 13:41:43
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:
CONT: N01-ES-95268                              ROUTE: DOSED WATER                                             NTP C#: 55301B
PATHOLOGIST: D. SAUER                                                                                          CAS: 110-86-1
                    

Rats(WISTAR OUTBRED)
-----------------------------
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.

                                                 ----------------
                                                 Kidney
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08   
LAB: TSI Mason Research                                         PYRIDINE                                       DATE: 09/26/97     
EXPERIMENT: 55301 TEST: 06                                                                                     TIME: 13:41:43     
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:              
CONT: N01-ES-95268                              ROUTE: DOSED WATER                                             NTP C#: 55301B     
PATHOLOGIST: D. SAUER                                                                                          CAS: 110-86-1      



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

Male Rats
------------
Organ                                 Morphology
-----                                 ----------
Kidney, Renal Tubule (Step Section)    Carcinoma and Adenoma
                                       Hyperplasia
                                       Hyperplasia and Adenoma
                                       Hyperplasia, Carcinoma or Adenoma
Kidney, Renal Tubule (Step and Original Sections)
                                       Hyperplasia
                                       Hyperplasia and Adenoma
                                       Hyperplasia, Carcinoma or Adenoma
Kidney: Renal Tubule                   Hyperplasia
                                       Hyperplasia and Adenoma
                                       Hyperplasia, Carcinoma or Adenoma
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 1
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)        -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step Section)                                                                                              |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  1/50 (2%)                2/50 (4%)                4/50 (8%)                2/50 (4%)       |
|POLY-3 ADJUSTED (b)|                  2.5%                     5.6%                     11.5%                    6.9%            |
|TERMINAL (d)       |                  1/22 (5%)                0/14 (0%)                2/11 (18%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  722 (T)                  611                      520                      550             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.114                  P=0.401                  P=0.064                  P=0.230         |
|POLY 3             |                  P=0.209                  P=0.459                  P=0.136                  P=0.388         |
|POLY 1.5           |                  P=0.281                  P=0.475                  P=0.153                  P=0.436         |
|POLY 6             |                  P=0.129                  P=0.441                  P=0.118                  P=0.325         |
|LOGISTIC REGRESSION|                  P=0.283                  P=0.461                  P=0.140                  P=0.394         |
|COCH-ARM / FISHERS |                  P=0.387                  P=0.500                  P=0.181                  P=0.500         |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step Section)                                                                                              |
|     Carcinoma and Adenoma                                                                                                       |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  1/50 (2%)                2/50 (4%)                5/50 (10%)               2/50 (4%)       |
|POLY-3 ADJUSTED (b)|                  2.5%                     5.6%                     14.4%                    6.9%            |
|TERMINAL (d)       |                  1/22 (5%)                0/14 (0%)                2/11 (18%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  722 (T)                  611                      520                      550             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.091                  P=0.401                  P=0.028 *                P=0.230         |
|POLY 3             |                  P=0.181                  P=0.459                  P=0.070                  P=0.388         |
|POLY 1.5           |                  P=0.257                  P=0.475                  P=0.082                  P=0.436         |
|POLY 6             |                  P=0.101                  P=0.441                  P=0.058                  P=0.325         |
|LOGISTIC REGRESSION|                  P=0.243                  P=0.461                  P=0.068                  P=0.394         |
|COCH-ARM / FISHERS |                  P=0.371                  P=0.500                  P=0.102                  P=0.500         |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 2
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step Section)                                                                                              |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  5/50 (10%)               13/50 (26%)              10/50 (20%)              9/50 (18%)      |
|POLY-3 ADJUSTED (b)|                  12.0%                    33.4%                    27.0%                    28.0%           |
|TERMINAL (d)       |                  1/22 (5%)                3/14 (21%)               3/11 (27%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  557                      352                      486                      486             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.023 *                P=0.013 *                P=0.035 *                P=0.016 *       |
|POLY 3             |                  P=0.109                  P=0.018 *                P=0.078                  P=0.074         |
|POLY 1.5           |                  P=0.189                  P=0.023 *                P=0.098                  P=0.115         |
|POLY 6             |                  P=0.047 *                P=0.014 *                P=0.058                  P=0.041 *       |
|LOGISTIC REGRESSION|                  P=0.369                  P=0.041 *                P=0.161                  P=0.235         |
|COCH-ARM / FISHERS |                  P=0.345                  P=0.033 *                P=0.131                  P=0.194         |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step Section)                                                                                              |
|     Hyperplasia and Adenoma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  6/50 (12%)               15/50 (30%)              12/50 (24%)              11/50 (22%)     |
|POLY-3 ADJUSTED (b)|                  14.4%                    38.0%                    31.6%                    33.5%           |
|TERMINAL (d)       |                  2/22 (9%)                3/14 (21%)               3/11 (27%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  557                      352                      486                      486             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.011 *                P=0.008 **               P=0.020 *                P=0.006 **      |
|POLY 3             |                  P=0.074                  P=0.012 *                P=0.056                  P=0.045 *       |
|POLY 1.5           |                  P=0.139                  P=0.016 *                P=0.070                  P=0.076         |
|POLY 6             |                  P=0.030 *                P=0.010 *                P=0.042 *                P=0.022 *       |
|LOGISTIC REGRESSION|                  P=0.291                  P=0.027 *                P=0.123                  P=0.146         |
|COCH-ARM / FISHERS |                  P=0.282                  P=0.024 *                P=0.096                  P=0.143         |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 3
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step Section)                                                                                              |
|     Hyperplasia, Carcinoma or Adenoma                                                                                           |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  6/50 (12%)               15/50 (30%)              13/50 (26%)              11/50 (22%)     |
|POLY-3 ADJUSTED (b)|                  14.4%                    38.0%                    34.1%                    33.5%           |
|TERMINAL (d)       |                  2/22 (9%)                3/14 (21%)               3/11 (27%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  557                      352                      486                      486             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.009 **               P=0.008 **               P=0.011 *                P=0.006 **      |
|POLY 3             |                  P=0.067                  P=0.012 *                P=0.032 *                P=0.045 *       |
|POLY 1.5           |                  P=0.130                  P=0.016 *                P=0.042 *                P=0.076         |
|POLY 6             |                  P=0.026 *                P=0.010 *                P=0.023 *                P=0.022 *       |
|LOGISTIC REGRESSION|                  P=0.270                  P=0.027 *                P=0.076                  P=0.146         |
|COCH-ARM / FISHERS |                  P=0.274                  P=0.024 *                P=0.062                  P=0.143         |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step and Original Sections)                                                                                |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  3/50 (6%)                6/50 (12%)               5/50 (10%)               4/50 (8%)       |
|POLY-3 ADJUSTED (b)|                  7.4%                     16.5%                    14.4%                    13.6%           |
|TERMINAL (d)       |                  1/22 (5%)                1/14 (7%)                2/11 (18%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  576                      610                      520                      550             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.104                  P=0.134                  P=0.142                  P=0.130         |
|POLY 3             |                  P=0.288                  P=0.187                  P=0.271                  P=0.328         |
|POLY 1.5           |                  P=0.391                  P=0.208                  P=0.306                  P=0.400         |
|POLY 6             |                  P=0.172                  P=0.168                  P=0.231                  P=0.241         |
|LOGISTIC REGRESSION|                  P=0.345                  P=0.204                  P=0.286                  P=0.369         |
|COCH-ARM / FISHERS |                  P=0.533                  P=0.243                  P=0.357                  P=0.500         |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 4
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step and Original Sections)                                                                                |
|     Carcinoma and Adenoma                                                                                                       |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  3/50 (6%)                6/50 (12%)               6/50 (12%)               4/50 (8%)       |
|POLY-3 ADJUSTED (b)|                  7.4%                     16.5%                    17.2%                    13.6%           |
|TERMINAL (d)       |                  1/22 (5%)                1/14 (7%)                2/11 (18%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  576                      610                      520                      550             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.087                  P=0.134                  P=0.076                  P=0.130         |
|POLY 3             |                  P=0.258                  P=0.187                  P=0.167                  P=0.328         |
|POLY 1.5           |                  P=0.365                  P=0.208                  P=0.197                  P=0.400         |
|POLY 6             |                  P=0.144                  P=0.168                  P=0.135                  P=0.241         |
|LOGISTIC REGRESSION|                  P=0.308                  P=0.204                  P=0.170                  P=0.369         |
|COCH-ARM / FISHERS |                  P=0.516                  P=0.243                  P=0.243                  P=0.500         |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step and Original Sections)                                                                                |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  10/50 (20%)              22/50 (44%)              14/50 (28%)              13/50 (26%)     |
|POLY-3 ADJUSTED (b)|                  23.7%                    52.0%                    36.5%                    37.8%           |
|TERMINAL (d)       |                  5/22 (23%)               5/14 (36%)               5/11 (46%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  468                      352                      354                      463             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.037 *                P=0.002 **               P=0.040 *                P=0.017 *       |
|POLY 3             |                  P=0.256                  P=0.005 **               P=0.149                  P=0.133         |
|POLY 1.5           |                  P=0.387                  P=0.005 **               P=0.186                  P=0.197         |
|POLY 6             |                  P=0.137                  P=0.004 **               P=0.111                  P=0.079         |
|LOGISTIC REGRESSION|                  P=0.411N                 P=0.013 *                P=0.278                  P=0.388         |
|COCH-ARM / FISHERS |                  P=0.490N                 P=0.009 **               P=0.241                  P=0.318         |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 5
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step and Original Sections)                                                                                |
|     Hyperplasia and Adenoma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  12/50 (24%)              25/50 (50%)              16/50 (32%)              16/50 (32%)     |
|POLY-3 ADJUSTED (b)|                  28.3%                    58.0%                    40.7%                    45.4%           |
|TERMINAL (d)       |                  6/22 (27%)               5/14 (36%)               5/11 (46%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  468                      352                      354                      463             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.015 *                P=0.002 **               P=0.036 *                P=0.005 **      |
|POLY 3             |                  P=0.203                  P=0.003 **               P=0.166                  P=0.087         |
|POLY 1.5           |                  P=0.321                  P=0.004 **               P=0.200                  P=0.139         |
|POLY 6             |                  P=0.107                  P=0.004 **               P=0.132                  P=0.048 *       |
|LOGISTIC REGRESSION|                  P=0.514N                 P=0.008 **               P=0.285                  P=0.236         |
|COCH-ARM / FISHERS |                  P=0.530                  P=0.006 **               P=0.252                  P=0.252         |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney, Renal Tubule (Step and Original Sections)                                                                                |
|     Hyperplasia, Carcinoma or Adenoma                                                                                           |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                  #                        #                        #                        #               |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  12/50 (24%)              25/50 (50%)              17/50 (34%)              16/50 (32%)     |
|POLY-3 ADJUSTED (b)|                  28.3%                    58.0%                    43.2%                    45.4%           |
|TERMINAL (d)       |                  6/22 (27%)               5/14 (36%)               5/11 (46%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  468                      352                      354                      463             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.013 *                P=0.002 **               P=0.022 *                P=0.005 **      |
|POLY 3             |                  P=0.189                  P=0.003 **               P=0.114                  P=0.087         |
|POLY 1.5           |                  P=0.306                  P=0.004 **               P=0.143                  P=0.139         |
|POLY 6             |                  P=0.096                  P=0.004 **               P=0.086                  P=0.048 *       |
|LOGISTIC REGRESSION|                  P=0.538N                 P=0.008 **               P=0.206                  P=0.236         |
|COCH-ARM / FISHERS |                  P=0.520                  P=0.006 **               P=0.189                  P=0.252         |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 6
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                                                                             |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  2/50 (4%)                5/50 (10%)               1/50 (2%)                2/50 (4%)       |
|POLY-3 ADJUSTED (b)|                  4.9%                     13.9%                    3.0%                     7.0%            |
|TERMINAL (d)       |                  0/22 (0%)                1/14 (7%)                0/11 (0%)                0/7 (0%)        |
|FIRST INCIDENCE    |                  576                      610                      721                      606             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.417                  P=0.128                  P=0.656N                 P=0.381         |
|POLY 3             |                  P=0.531N                 P=0.167                  P=0.564N                 P=0.562         |
|POLY 1.5           |                  P=0.459N                 P=0.186                  P=0.537N                 P=0.622         |
|POLY 6             |                  P=0.499                  P=0.149                  P=0.599N                 P=0.477         |
|LOGISTIC REGRESSION|                  P=0.539N                 P=0.186                  P=0.547N                 P=0.640         |
|COCH-ARM / FISHERS |                  P=0.371N                 P=0.218                  P=0.500N                 P=0.691N        |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                                                                             |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  2/50 (4%)                5/50 (10%)               1/50 (2%)                3/50 (6%)       |
|POLY-3 ADJUSTED (b)|                  4.9%                     13.9%                    3.0%                     10.4%           |
|TERMINAL (d)       |                  0/22 (0%)                1/14 (7%)                0/11 (0%)                0/7 (0%)        |
|FIRST INCIDENCE    |                  576                      610                      721                      606             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.206                  P=0.128                  P=0.656N                 P=0.161         |
|POLY 3             |                  P=0.420                  P=0.167                  P=0.564N                 P=0.348         |
|POLY 1.5           |                  P=0.501                  P=0.186                  P=0.537N                 P=0.413         |
|POLY 6             |                  P=0.316                  P=0.149                  P=0.599N                 P=0.268         |
|LOGISTIC REGRESSION|                  P=0.414                  P=0.186                  P=0.547N                 P=0.372         |
|COCH-ARM / FISHERS |                  P=0.562N                 P=0.218                  P=0.500N                 P=0.500         |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 7
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Hyperplasia                                                                                                                 |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                                                                             |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  6/50 (12%)               17/50 (34%)              8/50 (16%)               5/50 (10%)      |
|POLY-3 ADJUSTED (b)|                  14.5%                    41.6%                    22.0%                    16.2%           |
|TERMINAL (d)       |                  4/22 (18%)               3/14 (21%)               3/11 (27%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  468                      445                      354                      463             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.430                  P=0.003 **               P=0.122                  P=0.315         |
|POLY 3             |                  P=0.390N                 P=0.004 **               P=0.288                  P=0.552         |
|POLY 1.5           |                  P=0.255N                 P=0.005 **               P=0.330                  P=0.617N        |
|POLY 6             |                  P=0.489                  P=0.005 **               P=0.239                  P=0.438         |
|LOGISTIC REGRESSION|                  P=0.093N                 P=0.012 *                P=0.430                  P=0.434N        |
|COCH-ARM / FISHERS |                  P=0.131N                 P=0.008 **               P=0.387                  P=0.500N        |
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Hyperplasia and Adenoma                                                                                                     |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                                                                             |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  7/50 (14%)               20/50 (40%)              8/50 (16%)               7/50 (14%)      |
|POLY-3 ADJUSTED (b)|                  16.9%                    48.4%                    22.0%                    22.3%           |
|TERMINAL (d)       |                  4/22 (18%)               4/14 (29%)               3/11 (27%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  468                      445                      354                      463             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.293                  P<0.001 **               P=0.182                  P=0.138         |
|POLY 3             |                  P=0.443N                 P<0.001 **               P=0.390                  P=0.392         |
|POLY 1.5           |                  P=0.299N                 P=0.002 **               P=0.438                  P=0.486         |
|POLY 6             |                  P=0.436                  P<0.001 **               P=0.333                  P=0.281         |
|LOGISTIC REGRESSION|                  P=0.150N                 P=0.004 **               P=0.531                  P=0.621N        |
|COCH-ARM / FISHERS |                  P=0.159N                 P=0.003 **               P=0.500                  P=0.613N        |
|=================================================================================================================================|
       Date:  09/26/97                           EXPERIMENT: 55301 TEST: 06                                            Page 8
                     Statistical Analysis of Primary Tumors in Rats(WISTAR OUTBRED)       -                      PYRIDINE
                                         Terminal Sacrifice at 103 weeks 
|=================================================================================================================================|
|                   |                                                        |                                                    |
|                   |                                                      Males                                                  |
|Dose               |                  0 PPM                    100 PPM      |           200 PPM                  400 PPM         |
|                   |                                                        |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Hyperplasia, Carcinoma or Adenoma                                                                                           |
|                                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES        |                                                                                                             |
|-----------        |                                                                                                             |
|OVERALL (a)        |                  7/50 (14%)               20/50 (40%)              8/50 (16%)               8/50 (16%)      |
|POLY-3 ADJUSTED (b)|                  16.9%                    48.4%                    22.0%                    25.4%           |
|TERMINAL (d)       |                  4/22 (18%)               4/14 (29%)               3/11 (27%)               0/7 (0%)        |
|FIRST INCIDENCE    |                  468                      445                      354                      463             |
|-------------------|                                                                                                             |
|STATISTICAL TESTS  |                                                                                                             |
|-------------------|                                                                                                             |
|LIFE TABLE         |                  P=0.198                  P<0.001 **               P=0.182                  P=0.071         |
|POLY 3             |                  P=0.533                  P<0.001 **               P=0.390                  P=0.278         |
|POLY 1.5           |                  P=0.403N                 P=0.002 **               P=0.438                  P=0.367         |
|POLY 6             |                  P=0.333                  P<0.001 **               P=0.333                  P=0.182         |
|LOGISTIC REGRESSION|                  P=0.235N                 P=0.004 **               P=0.531                  P=0.472         |
|COCH-ARM / FISHERS |                  P=0.234N                 P=0.003 **               P=0.500                  P=0.500         |
|=================================================================================================================================|

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