Occupational exposure to toluene among automotive part industrial workers in eastern Thailand

Abstract

ABSTRACT            To determine the exposure levels and factors related to toluene exposure, 154 workers from five automotive part industries using toluene in the production process were monitored, using a combination of environmental and biological sampling. The results showed that toluene concentration in the production areas was 19-fold greater than that of office areas. The levels of personal toluene exposure in painting and mixing workers were significantly higher than production workers (P < 0.05), and higher than those in office areas (P < 0.001). The average urinary hippuric acid (HA) level in process workers was comparable with levels observed in office workers and much lower than the biological exposure index (BEI). Exposed levels were significantly influenced by working position, their use of chemical protective clothing, helmet and respirator, and some personal hygiene’s for chemical safety. Levels of toluene and HA detected in our study indicated low risk of toluene exposure. Urinary HA might be insufficient as an estimator of low toluene exposed workers, probably due to the reduced use of aromatics, i.e., toluene. Our results gave support to the argument for not using HA as an internal dose biomarker for low toluene exposures in some workplaces related to solvents including automotive part industry.