The results of MDA assay showed that MDA levels of two expo- sure groups were significantly higher than that of control group, as a consequence of high lipid peroxidation in workers exposed to organic BPs. The lipid peroxidation of exposure group I with higher exposure levels obviously increased, as compared with exposure group II with lower exposure concentrations. It was determined that the occupational exposure to organic BPs could induce lipid peroxidation which increased with exposure concentrations of organic BPs in air for occupational population. These findings were