Biological effects of short-term, high-concentration exposure to methyl isocyanate. I. Study objectives and inhalation exposure design
Early reports from India indicated that humans were dying within minutes to a few hours from exposure to methyl isocyanate (MIC). Attempts to explain the cause(s) of these rapid mortalities is where Union Carbide Corporation concentrated its post-Bhopal toxicologic investigations. The MIC studies involving rats and guinea pigs focused primarily on the consequences of acute pulmonary damage. All MIC inhalation exposures were acute, of short duration (mainly 15 min), and high in concentration. MIC vapors were statically generated in a double chamber exposure design. Precautionary measures taken during exposures are discussed. Guinea pigs were more susceptible than rats to MIC exposure-related early mortality. A greater than one order of magnitude difference was observed between an MIC concentration that caused no early mortality in rats (3506 ppm) and an MIC concentration that caused partial (6%) early mortality in guinea pigs (225 ppm) for exposures of 10 to 15 min duration. For both species, the most noteworthy clinical signs during exposure were lacrimation, blepharospasm, and mouth breathing. Fifteen minute LC/sub 50/ tests with 14-day postexposure follow-up were conducted, and the LC/sub 50/ (95% confidence limit) values were 171 (114-256) ppm for rats and 112 (61-204) ppm for guinea pigs. Target exposure concentrations for the toxicologic investigations of MIC-induced early mortality were established. A short summary of pertinent results of Union Carbide Corporation's post-Bhopal toxicologic investigations is presented.
- Research Organization:
- Union Carbide Corp., Export, PA
- OSTI ID:
- 6066018
- 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
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACUTE EXPOSURE
ANIMALS
BIOLOGICAL EFFECTS
BODY
DESIGN
DOSE-RESPONSE RELATIONSHIPS
DOSES
EXPOSURE CHAMBERS
GUINEA PIGS
INHALATION
INTAKE
ISOCYANATES
LETHAL DOSES
LUNGS
MAMMALS
MORTALITY
ORGANS
RATS
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES