A retrospective study of workers exposed to toluene-diisocyanate (26471625) (TDI) was performed. Diagnostic evaluations were done on 32 cases based on physical examination, pulmonary function measurements, and immunologic tests. Workroom air TDI values were tabulated and were found recently to average less than 0.004 parts per million (ppm) in normal operation, compared to 0.06ppm in the previous 14 years. During the 17 year history of the TDI facility, 30 of 300 persons in the population at risk became sensitized to TDI, with an onset of 2 to 14 years after initial exposure. The number of sensitivity cases per year did not increase with time, reflecting improved control of TDI concentration in air and increased knowledge of TDI effects. Immunologic testing in a subgroup of seven individuals with no physiological or clinical symptoms related to TDI contact gave a negative immunologic response, and generally normal lung function. Another subgroup of seven subjects showed immunologic capability in TDI response to form circulating gammaglobulin antibodies. Two of these had lung disease and reduced pulmonary function. A third group of workers was immunologically competent but no longer reacted with TDI antigens. Most showed lowered pulmonary function. In two subjects having identical work histories, age, pulmonary function, and immunologic capabilities, one showed TDI hypersensitivity. Two cases showed immediate sensitivity reaction without abnormal pulmonary function. Clinical problems were reversible and eliminated after removal from exposure. The authors conclude that the medical problems among the workers are not exclusively due to TDI exposure, reflecting the complicated nature of the diagnostic problem.
NIOSH-Author; Industrial-chemicals; Industrial-factory-workers; Industrial-exposures; Employee-exposure; Humans; Clinical-diagnosis; Pulmonary-function-tests; Lung-function; Chemical-industry-workers; Chemical-factory-workers; Industrial-environment; Breathing-atmospheres; Toxic-vapors; Chemical-manufacturing-industry