Safety and Health at Work 2010;1:51-60 Original Article

Objectives: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. Methods: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classifi ed into three stages: shut-down, maintenance and start-up. All works were classifi ed into 12 occupation categories. Results: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1 % (20 samples of 488) and 6.0 % (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically signifi cant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fi eldman and scaffolding workers exhibited long-term samples that exceede