Skip to Main Navigation
Skip to Page Content

COVID-19 is an emerging, rapidly evolving situation.

Get the latest public health information from CDC and research information from NIH.

U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
https://ntp.niehs.nih.gov/go/2544

TDMS Study 05156-05 Pathology Tables

NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51

                                                           CORE STUDY




       Facility:  Battelle Northwest

       Chemical CAS #:  10026-24-1

       Lock Date:  07/15/94

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All


































a  Number of animals examined microscopically at site and number of animals with lesion

                                                              Page   1

NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                19           20           20           17                                     
    Natural Death                                      3            4            4            3                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                28           25           26           30                                     
  Other                                                             1                                                               
  Animals Examined Microscopically                    50           49           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)         (49)         (50)         (50)                                   
      Inflammation, Suppurative                                                  1 (2%)                                             
   Intestine Large, Cecum                             (48)         (45)         (47)         (47)                                   
      Necrosis                                                                   1 (2%)                                             
   Liver                                              (50)         (49)         (50)         (49)                                   
      Angiectasis                                      6 (12%)      4 (8%)       1 (2%)       2 (4%)                                
      Basophilic Focus                                39 (78%)     37 (76%)     45 (90%)     41 (84%)                               
      Clear Cell Focus                                 7 (14%)      6 (12%)      5 (10%)     11 (22%)                               
      Cyst                                                                       1 (2%)                                             
      Degeneration, Fatty                              8 (16%)      9 (18%)      8 (16%)      2 (4%)                                
      Eosinophilic Focus                               4 (8%)       1 (2%)       1 (2%)       2 (4%)                                
      Hepatodiaphragmatic Nodule                       6 (12%)      6 (12%)      8 (16%)      4 (8%)                                
      Inflammation, Chronic Active                                  1 (2%)                                                          
      Mixed Cell Focus                                11 (22%)     11 (22%)     18 (36%)     15 (31%)                               
      Necrosis                                                      1 (2%)                                                          
      Regeneration                                                  1 (2%)       2 (4%)                                             
      Thrombosis                                       1 (2%)                                                                       
      Bile Duct, Hyperplasia                           5 (10%)      6 (12%)      9 (18%)      7 (14%)                               
      Centrilobular, Necrosis                          5 (10%)      6 (12%)      7 (14%)      5 (10%)                               
   Mesentery                                          (5)          (8)          (6)          (13)                                   
      Inflammation, Chronic Active                                                            1 (8%)                                
      Artery, Inflammation, Chronic Active                          1 (13%)                                                         
      Fat, Necrosis                                    5 (100%)     6 (75%)      6 (100%)    12 (92%)                               
   Pancreas                                           (49)         (49)         (50)         (48)                                   
      Atrophy                                         22 (45%)     11 (22%)     16 (32%)     16 (33%)                               
      Basophilic Focus                                                                        3 (6%)                                
      Hyperplasia                                                                             1 (2%)                                
      Artery, Inflammation                                                       1 (2%)                                             
   Salivary Glands                                    (50)         (49)         (50)         (50)                                   
      Atrophy                                          3 (6%)       4 (8%)       1 (2%)                                             
   Stomach, Forestomach                               (50)         (49)         (50)         (50)                                   
      Hyperplasia, Basal Cell                                       1 (2%)                                                          
      Hyperplasia, Squamous                                                      1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Necrosis                                         3 (6%)       2 (4%)       1 (2%)       1 (2%)                                
   Stomach, Glandular                                 (49)         (49)         (49)         (48)                                   
      Mineralization                                   1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Necrosis                                         4 (8%)                    1 (2%)                                             
   Tooth                                                           (2)                       (1)                                    
      Developmental Malformation                                    1 (50%)                                                         
      Inflammation, Chronic Active                                  1 (50%)                   1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                                 (1)                                                 
      Aorta, Inflammation, Chronic Active                                        1 (100%)                                           
   Heart                                              (50)         (49)         (50)         (50)                                   
      Cardiomyopathy                                  29 (58%)     24 (49%)     29 (58%)     23 (46%)                               
      Atrium, Thrombosis                                            1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (49)         (50)         (49)                                   
      Hyperplasia                                     21 (43%)     21 (43%)     25 (50%)     23 (47%)                               
      Hypertrophy                                      5 (10%)      3 (6%)       8 (16%)      9 (18%)                               
      Necrosis                                         1 (2%)                                                                       
      Vacuolization Cytoplasmic                       11 (22%)      5 (10%)     10 (20%)     12 (24%)                               
   Adrenal Medulla                                    (48)         (49)         (50)         (48)                                   
      Hyperplasia                                      8 (17%)      7 (14%)     11 (22%)     13 (27%)                               
   Pituitary Gland                                    (50)         (49)         (50)         (49)                                   
      Pars Distalis, Angiectasis                                                 2 (4%)                                             
      Pars Distalis, Cyst                                                                     1 (2%)                                
      Pars Distalis, Hyperplasia                       5 (10%)      5 (10%)      8 (16%)      5 (10%)                               
   Thyroid Gland                                      (49)         (49)         (50)         (48)                                   
      C-Cell, Hyperplasia                             37 (76%)     42 (86%)     37 (74%)     38 (79%)                               
      Follicular Cell, Hyperplasia                     2 (4%)                                 1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (48)         (48)         (49)                                   
      Hyperplasia                                      2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
      Inflammation, Chronic Active                     2 (4%)       6 (13%)      2 (4%)       6 (12%)                               
   Ovary                                              (50)         (49)         (50)         (49)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Cyst                                             5 (10%)      1 (2%)       3 (6%)                                             
   Uterus                                             (50)         (49)         (50)         (49)                                   
      Hydrometra                                                                              2 (4%)                                
      Cervix, Hypertrophy                                           1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (49)         (50)         (50)                                   
      Atrophy                                          2 (4%)                                 1 (2%)                                
      Hyperplasia, Histiocytic                                                   1 (2%)       1 (2%)                                
   Lymph Node                                         (2)          (3)          (3)          (2)                                    
      Renal, Hemorrhage                                             1 (33%)                                                         
   Lymph Node, Mandibular                             (44)         (40)         (47)         (45)                                   
      Infiltration Cellular, Plasma Cell                                                      1 (2%)                                
   Lymph Node, Mesenteric                             (49)         (49)         (50)         (48)                                   
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
      Infiltration Cellular, Eosinophil                                                       1 (2%)                                
   Lymph Node, Mediastinal                            (43)         (38)         (43)         (45)                                   
      Hemorrhage                                       1 (2%)                                 1 (2%)                                
      Infiltration Cellular, Plasma Cell                                         1 (2%)       1 (2%)                                
   Spleen                                             (49)         (48)         (50)         (49)                                   
      Accessory Spleen                                 1 (2%)       2 (4%)                                                          
      Fibrosis                                                      4 (8%)       2 (4%)                                             
      Hematopoietic Cell Proliferation                 3 (6%)       2 (4%)       4 (8%)       3 (6%)                                
      Hemorrhage                                       2 (4%)                    3 (6%)       1 (2%)                                
      Hyperplasia, Focal                                                                      1 (2%)                                
      Necrosis                                                                                1 (2%)                                
      Thrombosis                                                                              1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (49)         (50)         (49)                                   
      Galactocele                                                   2 (4%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                                                            1 (2%)                                
   Skin                                               (50)         (49)         (50)         (50)                                   
      Hyperkeratosis                                                1 (2%)                                                          
      Inflammation, Chronic                                                                   1 (2%)                                
      Inflammation, Chronic Active                                  4 (8%)       3 (6%)       3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (49)         (50)         (50)                                   
      Hyperostosis                                     4 (8%)       5 (10%)      5 (10%)      3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (49)         (50)         (50)                                   
      Gliosis                                                                                 1 (2%)                                
      Hemorrhage                                       2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (49)         (50)         (50)                                   
      Epiglottis, Metaplasia, Squamous                 1 (2%)      22 (45%)     39 (78%)     48 (96%)                               
   Lung                                               (50)         (49)         (50)         (50)                                   
      Congestion, Chronic                                           1 (2%)                                                          
      Cyst                                                                       1 (2%)                                             
      Metaplasia, Osseous                                                                     1 (2%)                                
      Metaplasia, Squamous                                          1 (2%)       8 (16%)      3 (6%)                                
      Pigmentation, Hemosiderin                                     1 (2%)                                                          
      Proteinosis                                                  36 (73%)     49 (98%)     49 (98%)                               
      Alveolar Epithelium, Hyperplasia                15 (30%)      7 (14%)     20 (40%)     33 (66%)                               
      Alveolar Epithelium, Hyperplasia, Atypical                                 3 (6%)       5 (10%)                               
      Alveolar Epithelium, Metaplasia                  2 (4%)      47 (96%)     50 (100%)    49 (98%)                               
      Alveolus, Inflammation, Granulomatous            9 (18%)     47 (96%)     50 (100%)    49 (98%)                               
      Interstitium, Fibrosis                           7 (14%)     47 (96%)     50 (100%)    49 (98%)                               
      Perivascular, Inflammation, Chronic Active                                              1 (2%)                                
   Nose                                               (50)         (49)         (50)         (50)                                   
      Inflammation, Suppurative                        6 (12%)     10 (20%)      2 (4%)       4 (8%)                                
      Thrombosis                                       4 (8%)       4 (8%)       3 (6%)       2 (4%)                                
      Lateral Wall, Hyperplasia                        1 (2%)       8 (16%)     26 (52%)     38 (76%)                               
      Lateral Wall, Metaplasia, Squamous               1 (2%)       1 (2%)       4 (8%)      10 (20%)                               
      Nasolacrimal Duct, Metaplasia, Squamous                       1 (2%)                                                          
      Olfactory Epithelium, Atrophy                    5 (10%)     29 (59%)     46 (92%)     47 (94%)                               
      Olfactory Epithelium, Metaplasia                 2 (4%)       2 (4%)       3 (6%)      40 (80%)                               
      Respiratory Epithelium, Hyperplasia, Focal       1 (2%)                                                                       
      Respiratory Epithelium, Metaplasia, Squamous     2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (1)          (5)          (3)          (3)                                    
      Cataract                                         1 (100%)     4 (80%)      3 (100%)     2 (67%)                               
      Cornea, Edema                                                 1 (20%)                                                         
      Retina, Atrophy                                  1 (100%)     4 (80%)      3 (100%)     1 (33%)                               
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (49)         (50)         (48)                                   
      Hyperplasia, Stromal                                                                    1 (2%)                                
      Infarct                                          1 (2%)                    2 (4%)       2 (4%)                                
      Nephropathy                                     47 (96%)     48 (98%)     45 (90%)     48 (100%)                              
      Renal Tubule, Hyperplasia                                                  1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                30           34           26           34                                     
    Natural Death                                      3            1            3            1                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                17           15           21           15                                     
  Animals Examined Microscopically                    50           50           50           50                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)         (50)         (50)         (50)                                   
      Inflammation, Suppurative                                                  1 (2%)                                             
   Intestine Small, Jejunum                           (49)         (49)         (47)         (49)                                   
      Inflammation, Chronic Active                                  1 (2%)                                                          
   Liver                                              (50)         (50)         (48)         (50)                                   
      Angiectasis                                      5 (10%)      1 (2%)                    1 (2%)                                
      Basophilic Focus                                13 (26%)     16 (32%)     23 (48%)     21 (42%)                               
      Clear Cell Focus                                 8 (16%)      5 (10%)      8 (17%)      6 (12%)                               
      Degeneration, Cystic                            10 (20%)     11 (22%)     16 (33%)     10 (20%)                               
      Degeneration, Fatty                              6 (12%)      5 (10%)      5 (10%)      6 (12%)                               
      Eosinophilic Focus                               2 (4%)                    3 (6%)       5 (10%)                               
      Hepatodiaphragmatic Nodule                       1 (2%)       4 (8%)       4 (8%)       6 (12%)                               
      Mixed Cell Focus                                 3 (6%)       3 (6%)       4 (8%)       5 (10%)                               
      Necrosis                                                      2 (4%)       1 (2%)       1 (2%)                                
      Regeneration                                     3 (6%)       1 (2%)       1 (2%)       1 (2%)                                
      Thrombosis                                       1 (2%)       1 (2%)                                                          
      Bile Duct, Hyperplasia                          41 (82%)     42 (84%)     34 (71%)     35 (70%)                               
      Centrilobular, Necrosis                         17 (34%)     19 (38%)      5 (10%)     11 (22%)                               
   Mesentery                                          (21)         (14)         (11)         (14)                                   
      Fat, Hemorrhage                                  1 (5%)                    1 (9%)                                             
      Fat, Necrosis                                   20 (95%)     11 (79%)      9 (82%)     13 (93%)                               
   Pancreas                                           (50)         (50)         (48)         (50)                                   
      Angiectasis                                                   1 (2%)                                                          
      Atrophy                                         25 (50%)     25 (50%)     20 (42%)     28 (56%)                               
      Basophilic Focus                                 3 (6%)       2 (4%)       6 (13%)      3 (6%)                                
      Hyperplasia                                      2 (4%)       1 (2%)       4 (8%)       1 (2%)                                
      Metaplasia, Hepatocyte                                        1 (2%)                                                          
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
      Atrophy                                          2 (4%)       2 (4%)                    1 (2%)                                
   Stomach, Forestomach                               (50)         (50)         (49)         (50)                                   
      Hyperplasia, Basal Cell                                       1 (2%)                                                          
      Hyperplasia, Squamous                                         1 (2%)                                                          
      Necrosis                                         6 (12%)      5 (10%)     10 (20%)      3 (6%)                                
   Stomach, Glandular                                 (50)         (50)         (48)         (50)                                   
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Inflammation, Acute                                           1 (2%)                                                          
      Mineralization                                   1 (2%)       2 (4%)       1 (2%)       1 (2%)                                
      Necrosis                                         3 (6%)       2 (4%)       5 (10%)      2 (4%)                                
   Tongue                                             (1)                                    (2)                                    
      Hyperplasia, Squamous                            1 (100%)                               1 (50%)                               
      Epithelium, Cyst                                                                        1 (50%)                               
   Tooth                                                                        (1)          (1)                                    
      Developmental Malformation                                                 1 (100%)     1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                                              (1)                                    
      Aorta, Mineralization                                                                   1 (100%)                              
   Heart                                              (50)         (50)         (50)         (50)                                   
      Cardiomyopathy                                  38 (76%)     46 (92%)     45 (90%)     38 (76%)                               
      Atrium, Thrombosis                               2 (4%)       4 (8%)       1 (2%)       4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (48)         (50)                                   
      Hyperplasia                                     26 (52%)     24 (48%)     26 (54%)     24 (48%)                               
      Hypertrophy                                      2 (4%)       5 (10%)      5 (10%)      5 (10%)                               
      Necrosis                                         2 (4%)       1 (2%)                    3 (6%)                                
      Thrombosis                                                                 1 (2%)                                             
      Vacuolization Cytoplasmic                        6 (12%)      4 (8%)       3 (6%)       3 (6%)                                
   Adrenal Medulla                                    (50)         (50)         (49)         (50)                                   
      Cyst                                                                                    1 (2%)                                
      Hyperplasia                                     34 (68%)     23 (46%)     29 (59%)     30 (60%)                               
   Islets, Pancreatic                                 (50)         (50)         (48)         (50)                                   
      Hyperplasia                                                   1 (2%)                                                          
   Parathyroid Gland                                  (48)         (48)         (49)         (49)                                   
      Hyperplasia                                      1 (2%)       1 (2%)       3 (6%)       1 (2%)                                
   Pituitary Gland                                    (49)         (49)         (50)         (49)                                   
      Pars Distalis, Hyperplasia                       4 (8%)       5 (10%)      4 (8%)       5 (10%)                               
   Thyroid Gland                                      (49)         (50)         (48)         (50)                                   
      C-Cell, Hyperplasia                             31 (63%)     32 (64%)     32 (67%)     34 (68%)                               
      Follicular Cell, Hyperplasia                     2 (4%)                    1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
      Granuloma Sperm                                  1 (2%)       3 (6%)                                                          
   Preputial Gland                                    (50)         (50)         (49)         (50)                                   
      Hyperplasia                                      1 (2%)                                                                       
      Inflammation, Chronic Active                    11 (22%)     10 (20%)      3 (6%)      12 (24%)                               
   Prostate                                           (50)         (50)         (49)         (50)                                   
      Hyperplasia                                     12 (24%)      8 (16%)      5 (10%)      9 (18%)                               
      Inflammation, Chronic Active                     3 (6%)       4 (8%)       1 (2%)       1 (2%)                                
      Necrosis                                                                                1 (2%)                                
   Seminal Vesicle                                    (50)         (50)         (49)         (49)                                   
      Inflammation, Chronic Active                                               1 (2%)                                             
      Necrosis                                                                                1 (2%)                                
   Testes                                             (50)         (50)         (50)         (50)                                   
      Atrophy                                          2 (4%)       4 (8%)       5 (10%)                                            
      Artery, Inflammation, Chronic Active             1 (2%)       1 (2%)       2 (4%)       3 (6%)                                
      Interstitial Cell, Hyperplasia                  13 (26%)     10 (20%)      6 (12%)     10 (20%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (48)         (50)                                   
      Necrosis                                                      1 (2%)                                                          
   Lymph Node                                         (8)          (9)          (9)          (9)                                    
      Iliac, Ectasia                                                                          1 (11%)                               
      Iliac, Hemorrhage                                                                       1 (11%)                               
      Pancreatic, Ectasia                                                        1 (11%)                                            
      Renal, Hemorrhage                                                          1 (11%)                                            
   Lymph Node, Bronchial                              (45)         (30)         (41)         (49)                                   
      Inflammation, Suppurative                                                  1 (2%)                                             
   Lymph Node, Mandibular                             (46)         (47)         (47)         (49)                                   
      Infiltration Cellular, Plasma Cell                                                      1 (2%)                                
   Lymph Node, Mediastinal                            (47)         (46)         (44)         (49)                                   
      Hemorrhage                                                    1 (2%)                    1 (2%)                                
   Spleen                                             (50)         (50)         (49)         (50)                                   
      Accessory Spleen                                 1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
      Depletion Cellular                                                         1 (2%)                                             
      Fibrosis                                        16 (32%)     16 (32%)     12 (24%)     13 (26%)                               
      Hematopoietic Cell Proliferation                 1 (2%)       1 (2%)       1 (2%)                                             
      Hyperplasia, Focal                                                                      1 (2%)                                
      Necrosis                                         2 (4%)                    1 (2%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (30)         (34)         (36)         (38)                                   
      Galactocele                                      2 (7%)       1 (3%)                    1 (3%)                                
      Hyperplasia, Atypical                                                      1 (3%)                                             
   Skin                                               (50)         (48)         (50)         (50)                                   
      Cyst Epithelial Inclusion                        1 (2%)                                                                       
      Inflammation, Chronic                            3 (6%)       1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Chronic Active                     1 (2%)       2 (4%)                    3 (6%)                                
      Subcutaneous Tissue, Edema                                                              1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Fibrous Osteodystrophy                                                     2 (4%)                                             
      Hyperostosis                                     2 (4%)       2 (4%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Developmental Malformation                                    1 (2%)                                                          
      Gliosis                                          1 (2%)       1 (2%)       1 (2%)                                             
      Mineralization                                                1 (2%)                                                          
      Necrosis                                         2 (4%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (50)         (49)         (48)         (50)                                   
      Epiglottis, Metaplasia, Squamous                             10 (20%)     37 (77%)     50 (100%)                              
   Lung                                               (50)         (50)         (48)         (50)                                   
      Cyst                                                                                    1 (2%)                                
      Foreign Body                                                                            1 (2%)                                
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia, Atypical                                                      1 (2%)       1 (2%)                                
      Infiltration Cellular, Histiocyte                             1 (2%)       1 (2%)       1 (2%)                                
      Inflammation, Suppurative                                                               1 (2%)                                
      Metaplasia, Squamous                                          1 (2%)       4 (8%)       2 (4%)                                
      Mineralization                                                                          1 (2%)                                
      Proteinosis                                                  16 (32%)     40 (83%)     47 (94%)                               
      Thrombosis                                                    1 (2%)                    1 (2%)                                
      Alveolar Epithelium, Hyperplasia                 9 (18%)     20 (40%)     20 (42%)     23 (46%)                               
      Alveolar Epithelium, Hyperplasia, Atypical                    1 (2%)       2 (4%)       2 (4%)                                
      Alveolar Epithelium, Metaplasia                              50 (100%)    48 (100%)    49 (98%)                               
      Alveolus, Inflammation, Granulomatous            2 (4%)      50 (100%)    48 (100%)    50 (100%)                              
      Artery, Mediastinum, Mineralization                                                     1 (2%)                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05156-05         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                    COBALT SULFATE HEPTAHYDRATE                                Date: 07/25/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:33:51  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     CONTROL      0.3          1.0          3.0                                       
                                                                MG/M3        MG/M3        MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Bronchiole, Inflammation, Chronic                                                       1 (2%)                                
      Interstitium, Fibrosis                           1 (2%)      50 (100%)    48 (100%)    49 (98%)                               
      Mediastinum, Inflammation, Suppurative                                     1 (2%)                                             
   Nose                                               (50)         (50)         (49)         (50)                                   
      Inflammation, Chronic Active                     1 (2%)                                                                       
      Inflammation, Suppurative                        4 (8%)      15 (30%)      5 (10%)      6 (12%)                               
      Metaplasia, Squamous                             1 (2%)                                                                       
      Thrombosis                                      14 (28%)     18 (36%)      3 (6%)       9 (18%)                               
      Glands, Cyst                                     1 (2%)                                                                       
      Lateral Wall, Hyperplasia                        2 (4%)      14 (28%)     21 (43%)     20 (40%)                               
      Lateral Wall, Inflammation                                                              1 (2%)                                
      Lateral Wall, Metaplasia, Squamous               1 (2%)       3 (6%)       5 (10%)      8 (16%)                               
      Olfactory Epithelium, Atrophy                    8 (16%)     24 (48%)     42 (86%)     48 (96%)                               
      Olfactory Epithelium, Metaplasia                 5 (10%)      1 (2%)       5 (10%)     30 (60%)                               
      Respiratory Epithelium, Hyperplasia, Focal       6 (12%)      1 (2%)       3 (6%)       2 (4%)                                
      Respiratory Epithelium, Inflammation             4 (8%)                                 1 (2%)                                
      Respiratory Epithelium, Metaplasia, Squamous     1 (2%)                                 1 (2%)                                
   Trachea                                            (50)         (50)         (48)         (50)                                   
      Mineralization                                                                          1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (5)                       (1)          (1)                                    
      Cataract                                         5 (100%)                  1 (100%)     1 (100%)                              
      Retina, Atrophy                                  5 (100%)                  1 (100%)     1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (48)         (50)                                   
      Cyst                                             1 (2%)                                 1 (2%)                                
      Hydronephrosis                                                1 (2%)                    1 (2%)                                
      Infarct                                          4 (8%)       1 (2%)       1 (2%)       3 (6%)                                
      Nephropathy                                     49 (98%)     49 (98%)     48 (100%)    50 (100%)                              
      Thrombosis                                                                 1 (2%)                                             
      Papilla, Necrosis                                                                       1 (2%)                                
      Renal Tubule, Hyperplasia                        2 (4%)       4 (8%)       2 (4%)       2 (4%)                                
   Urinary Bladder                                    (50)         (50)         (48)         (50)                                   
      Necrosis                                                                                1 (2%)                                
      Transitional Epithelium, Hyperplasia                                                    1 (2%)                                
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------