A comparison of benzene exposures in maintenance and regular works at Korean petrochemical plants

The goal of this study was to compare the exposure levels of benzene in maintenance and regular works at the petrochemical plant. Four companies handling benzene were investigated during maintenance and regular works. The data were analyzed by classifying the workers into two groups (maintenance operations: 129, regular operations: 63) comprising a total of 192 plant workers. Benzene concentrations in long-term samples during maintenance were found to be 1.7-9 times higher than those during regular operations; furthermore, benzene concentrations in short-term samples during maintenance were 20 times higher than those during regular operations (p < 0.01). For personal air samples, the exceedances above the ACGIH TLV for benzene were 17.8% during maintenance operations and were not significant during regular operations. In short-term air samples, the exceedances above TLV were 11.1% during maintenance works and none of the samples exceeded the TLVs during regular operations. Therefore, the periodic monitoring according to manual which is standardized is necessary to reinforce during maintenance operations.