Objectives The purpose of this study was to assess potential occupational exposure to chemicals among workers using both qualitative and quantitative information during specific job tasks on the photolithography process of a semiconductor manufacturing facility.

Method Historical exposure measurement data from 1997 to 2012 (n = 1347) were collected and classified by each type of chemical during 8 of 36 job tasks, and hallmark risk assessment was performed to determine control bands by job task of interest using the qualitative information on health hazard, duration of use, quantity, exposure control, etc. Finally, Bayesian Decision Analysis was performed to evaluate potential exposure ratings for those 8 job tasks by combining the prior distribution and likelihood distribution into the posterior distribution.

Results Control bands for 8 job tasks of interest were determined as 1, interpreting that workers use appropriate industrial hygiene, follow recommended job practices, wear personal protective equipment, and instal proper ventilation systems. Arithmetic mean and standard deviation for 7 types of chemicals from historical exposure measurement data were 2-heptanone 0.013 ± 0.011 ppm, 1-methoxypropyl-2-acetate 0.163 ± 0.261 ppm, acetone 0.456 ± 0.609 ppm, ethyl 3-ethoxy propionate 0.131 ± 0.106 ppm, ethyl lactate 0.058 ± 0.067 ppm, isopropyl alcohol 0.594 ± 0.923 ppm, and n-butyl acetate 0.071 ± 0.368 ppm, respectively, and all concentrations of chemicals were below 10% of OELs. Therefore, exposure ratings of the 8 job tasks were determined as exposure category 1, indicating that the 95th percentile of exposures infrequently exceed 10% of the OELs.

Conclusions In conclusion, the study findings suggest that potential exposures to chemicals of interest among semiconductor workers for 16 years were very low (below 10% of the OELs) and “highly controlled.”