HazMap: Occupational Exposure to Hazardous Agents


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Agent Name ISOCYANATES
Alternative Name CLASS
Major Category Plastics & Rubber
Category Isocyanates
Sources/Uses MDI is used to make rigid foams, while both TDI and MDI are used to make flexible foams, elastomers, and surface coatings. The diisocyanate chemicals, e.g., TDI or MDI, along with various polyols, catalysts, blowing agents, surfactants, and other agents are needed to manufacture urethane polymers. [Klees JE, Ott MG. Diisocyanates in Polyurethane Plastics Applications. Occup Med STAR 14(4):760-2,1999]
Comments Diisocyanates, also referred to as isocyanates, are organic compounds with two isocyanate groups (-NCO). They are used to make polyurethane coatings and rigid and flexible foams. Isocyanates are the leading cause of occupational asthma in many post-industrial countries where incidence rates have been measured. Commonly used isocyanates are toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI) and polymethylene polyphenyl isocyanate (PAPI). [LaDou, p. 314-5 and p. 521-3] Exposure can occur to vapors at room temperature (TDI and HDI), or after heating (MDI and PAPI), or during spraying processes (all isocyanates). [Sullivan, p. 470-2] "Isocyanate HP," a form of hypersensitivity pneumonitis, has been reported. [Rosenstock, p. 243] Some of the isocyanates are known to cause acute pneumonitis and pulmonary edema. Some are known skin sensitizers. See "Toluene-2,4 diisocyanate" and "Methylene bisphenyl isocyanate."
Reference Link OSHA Technical Links: Isocyanates
Adverse Effects
Asthma Yes
Toxic Pneumonitis Yes
Fibrogenic Yes
Skin Sensitizer Yes
Links to Other NLM Databases
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Diseases Diseases associated with exposure to this agent:
Processes Industrial Processes with risk of exposure:
Activities Activities with risk of exposure:





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Last updated: July 20, 2004