Methyl isocyanate eight-day vapor inhalation study with Fischer 344 rats
Groups of ten male and ten female Fischer 344 rats were exposed by inhalation 3.1, 0.6, 0.15, or 0.0 (control) ppm of methyl isocyanate (MIC) vapor 6 hr per day for 8 days (two 4-day sessions separated by a 2-day rest). Evaluation of toxic effects included body weight, food consumption, organ weights, and selected hematologic, ophthalmic, neurologic, gross anatomic, and histologic examinations. There were no deaths during the study. Rats of the 3.1 ppm exposure group had decreased body weights, food consumption, and blood oxygen saturation (males only). An increase in hemoglobin concentration (males only) and in lung weights (absolute and as a percentage of body weight) were also observed in the 3.1 ppm rats. Ophthalmic or neurofunctional behavior evaluations were negative for all MIC exposure groups. Only 3.1 ppm of MIC vapor resulted in lesions in the respiratory tract, 0.6 or 0.15 ppm did not. The types of lesions observed were inflammation and squamous metaplasia in the nasal cavity, trachea, and bronchi; inflammation of the bronchioles and alveoli; and submucosal fibroplasia of the bronchioles. No significant lesions were observed in tissues other than those of the respiratory tract in all MIC exposure groups. The results of this study indicate the current 0.2 ppm threshold limit value for MIC is not too high regarding toxicity.
- Research Organization:
- Union Carbide Corp., Export, PA
- OSTI ID:
- 6016233
- Journal Information:
- Environ. Health Perspect.; (United States), Journal Name: Environ. Health Perspect.; (United States) Vol. 72; ISSN EVHPA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Respiratory tract changes in guinea pigs, rats, and mice following a single six-hour exposure to methyl isocyanate vapor
Toxicity of dimethylamine in F-344 rats and B6C3F1 mice following a 1-year inhalation exposure
Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
FEEDING
FEMALES
FIBROSIS
FLUIDS
GASES
HEMATOLOGY
HISTOLOGY
INFLAMMATION
INHALATION
INTAKE
ISOCYANATES
MALES
MAMMALS
MEDICINE
PATHOLOGICAL CHANGES
RATS
RESPIRATORY SYSTEM
RODENTS
SAFETY STANDARDS
STANDARDS
SYMPTOMS
VAPORS
VERTEBRATES
WEIGHT