title: Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries.
abstract: OBJECTIVE
  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 classified into three stages: shut-down, maintenance and start-up. All works were classified 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 significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05).
  
  
  CONCLUSIONS
  These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.
authors.affiliation: Department of Occupational Environment Research, Occupational Safety and Health Research Institute, KOSHA, Incheon, Korea.
authors.forename: Eun-Kyo
authors.initials: EK
authors.lastname: Chung
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Shin
authors.forename: Byung-Kyu
authors.initials: BK
authors.lastname: Lee
authors.forename: Jiwoon
authors.initials: J
authors.lastname: Kwon
authors.forename: Naroo
authors.initials: N
authors.lastname: Lee
authors.forename: Kwang-Jae
authors.initials: KJ
authors.lastname: Chung
authors.forename: Jong-Han
authors.initials: JH
authors.lastname: Lee
authors.forename: In-Seop
authors.initials: IS
authors.lastname: Lee
authors.forename: Seong-Kyu
authors.initials: SK
authors.lastname: Kang
authors.forename: Jae-Kil
authors.initials: JK
authors.lastname: Jang