Toluene Diisocyanate Exposure: Exposure Assessment and Development of Cross-Facility Similar Exposure Groups Among Toluene Diisocyanate Production Plants.

Objective: The objective of this study was to characterize workplace toluene diisocyanate (TDI) exposures using standardized industrial hygiene exposure assessment procedures for use in a prospective epidemiologic study of occupational asthma.

Methods: Over 2300 representative routine full shift time-weighted average (TWA) and short-term high potential exposure tasks (HPETs) air samples in groups across three TDI plants were collected over a nearly 7-year period.

Results: Data-derived similar exposure groups (SuperSEGs) were developed across the plants based on TWA sampling using cluster analysis. Individual cumulative exposure estimates were developed on the basis of the SuperSEGs.

Conclusion: Workplace TWA exposures to TDI were adequately characterized quantitatively, but HPET exposures were adequately characterized only by qualitative measures. The mean TWA exposure was 0.65 parts per billion for 1594 routine samples. These TWA and HPET exposures can be used to support exposure-response analyses.