An outbreak of naphthalene di-isocyanate-induced asthma in a plastics factory.

Seven cases of possible naphthalene di-isocyanate-related occupational asthma occurred in 1987 and 1988. These cases were reported to the National Institute for Occupational Safety and Health by personnel at a Midwest factory that manufactured plastic wheels for fork-lift trucks. The reporting of cases prompted (a) an evaluation of the workplace, including a medical screening of workers, to detect additional cases; and (b) an industrial-hygiene survey to determine the level of exposure to isocyanates.