Assessing inhalatory and dermal exposures and their resultant health-risks for workers exposed to polycyclic aromatic hydrocarbons (PAHs) contained in oil mists in a fastener manufacturing industry

This study first assessed workers' inhalatory and dermal exposures to polycyclic aromatic hydrocarbons (PAHs) contained in oil mists. Then, their resultant lung cancer and skin cancer risks were estimated. Finally, control strategies were initiated from the health-risk management aspect. All threading workers in a fastener manufacturing plant were included. 16 inhalatory and 88 dermal PAH exposure samples were collected. Results show that the inhalatory gas phase total PAH exposure level (8.60 × 10⁴ ng/m³) was much higher than that of particle phase (2.30 × 10³ ng/m³). Workers' mean inhalatory exposure level (8.83 × 10⁴ ng/m³) was lower, but its corresponding 1-sided upper 95% confidence level (UCL_1,95% =1.02 × 10⁵ ng/m³) was higher than the time-weighted average permissible exposure level (PEL-TWA) regulated in Taiwan for PAHs (1.00 × 10⁵ ng/m³). The mean whole body total PAHs dermal exposure levels was 5.44 × 10⁶ ng/day and the top five exposed surface areas were lower arm, hand, upper arm, neck, and head/front. The estimated lifetime skin cancer risk (9.72 × 10^{- 3}) was lower than that of lung cancer risk (1.64 × 10^{- 2}), but both were higher than the significant risk level (10^{- 3}) defined by the US Supreme Court in 1980. The installation of a local exhaust ventilation system at the threading machine should be considered as the first priority measurement because both lung and skin cancer risks can be reduced simultaneously. If the personal protection equipment would be adopted in the future, both respiratory protection equipment and protective clothing should be used simultaneously.