Diisocyanates toxicity data

The paucity of data on MIC at the time of the Bhopal accident and extensive toxicity data on diisocyanates (Anonymous, 1966 Varma, 1986) prompted the prestigious journal Lancet (Anonymous, 1984a) to comment, In a year s time wc will have learned a lot more about methyl isocyanate — at an appalling price. Indeed, wc did learn a lot in a few years time. The U.S. National Toxicology... 

Most of the toxicity data available relates to the diisocyanates TDI, MDI... 

Toxicity Data for the Analogues Aromatic and Aliphatic Diisocyanates... 

The primary purpose of this ehapter is to provide publie health offieials, physieians, toxicologists, and other interested individuals and groups with an overall perspeetive of the toxieology of hexamethylene diisocyanate. It contains descriptions and evaluations of toxicologieal studies and epidemiological investigations and provides conclusions, where possible, on the relevanee of toxicity and toxicokinetic data to public health. 

In addition to their local irritant effects on the respiratory tract, the diisocyanates also have a propensity to induce an immimological response in some individuals, which is characterized by an asthma-like respiratory reaction, and will induce the formation of antibodies to both the monomeric and polymer forms of HDl. A few studies have examined the immimological effects of HDl toxicity in humans, with some data available from laboratory animal studies as well. 

NIOSH REL (Diisocyanates) TWA 0.005 ppm CL 0.02 ppm/lOM SAFETY PROFILE Poison by intravenous route. A strong sensitizer. Questionable carcinogen with experimental carcinogenic data. When heated to decomposition it emits toxic fumes of NOx. See also CYANATES. 

NIOSH REL (Diisocyanates) TWA 0.005 ppm CL 0.02 ppm/lOM DOT CLASSIFICATION 6.1 Label KEEP AWAY FROM FOOD DOT Class 6.1 Label Poison DOT Class 6.1 Label Poison, Flammable Liquid DOT Class 3 Label Flammable Liquid, Poison SAFETY PROFILE Poison by inhalation. Mildly toxic by ingestion. Human systemic effects by inhalation increased immune response and body temperature. A skin and eye irritant. An allergic sensitizer. Questionable carcinogen. Mutation data reported. A flammable liquid. When heated to decomposition it emits toxic fumes of NOx and SOx. See also CYANATES. 

Moderate to high toxicity toxic route—inhalation LD50 data not available in humans, acute toxic symptoms can be bronchitis, wheezing, congestion in chest, and pulmonary edema—similar to other aromatic diisocyanates low oral toxicity LD50 intravenous (mice) 5.6 mg/kg exposure limits TLV-TWA (relative to diisocyanate) 0.0327 mg/m ... 

Diphenylmethane Diisocyanate— Fire Hazards Flash Pmnt (deg. F) 425 OC Flammable Limits in Air (%) Not pertinent Fire Extinguishing Agents Carbon dioxide or dry chemical Fire Extinguishing Agents Not to be Used Not pertinent Special Hazards of Combustion Products Toxic vapors are generated when heated Behavior in Fire Solid melts and bums Ignition Tenyterature (deg. F) Data not available Electrical Hazard Not pertinent Burning Rate Not pertinent Chertrical Reactivity Reactivity with Water Slow, non-hazardous. Form carbon dioxide gas Reactivity with Common Materials (lata not available ... 

TDI has a sharp, pungent, sweetish odor. Its vapors are toxic. Certain precautions are necessary when handling or using toluene diisocyanate. Before using TDI, obtain and study ARCO Chemical s Material Safety Data Sheet (MSDS) and product literature. For more information, see TDI Safety and Handling below. 

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