Exposure assessment among US workers employed in semiconductor wafer fabrication.

Objective: To classify 100,081 semiconductor workers employed during 1983-2002, and some as early as 1968, regarding potential for chemical exposures in cleanrooms during silicon wafer fabrication. Methods: This study involved site visits to 10 cities with fabrication facilities, evaluation of 12,300 personal air samples for >60 chemicals, and examination of >37,000 departments and >8600 job codes to develop exposure groupings. Results: Each worker was classified into one of five exposure groups on the basis of job-department combinations: 1) fabrication process equipment operators or process equipment service technicians working in cleanrooms (n = 28,583); 2) professionals such as supervisors working in fabrication areas (n = 8642); 3) professionals and office workers in nonfabrication areas (n = 53,512); 4) back-end workers (n = 5256); or 5) other nonfabrication workers (n = 4088). More than 98% of the personal air samples were below current occupational exposure limits. Conclusions: Although specific chemical exposures at the level of the individual could not be quantified, semiconductor workers were classified into broad exposure groups for assessment of cancer mortality in an epidemiologic study.