Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries

Abstract

ObjectivesThe 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.MethodsFrom 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.ResultsThe 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).ConclusionThese findings suggest that the periodic work environment must be assessed during non-routine works such as TA.

Personal exposure to benzene and 1,3-butadiene during petroleum refinery turnarounds and work in the oil harbour

“…A limited number of personal measurements of the benzene exposure during refinery turnarounds have been reported in the literature (Chung et al 2010 ; Gaffney et al 2010 , 2011 ; Kreider et al 2010 ). Although the data are scarce, the exposure to benzene is generally higher during a turnaround compared to normal production (Capleton and Levy 2005 ; Gaffney et al 2011 ; Kreider et al 2010 ).…”

Estimating Benzene Exposure Level over Time and by Industry Type through a Review of Literature on Korea

“…A large proportion of the benzene measurement results in those periods (78% in 2005–2009 and 25% in 2010–2013) were derived from extensive studies on petrochemical industry workplaces conducted between 2000 and 2003. These exposure assessment results included maintenance work and peak exposure [34] , resulting in a high level of benzene since 2005. Currently, even if occupational exposure in regular operations or work can be tightly controlled, benzene exposure for maintenance work performed regularly or irregularly could still be high, regardless of industry type.…”

“…The proportion of turnaround maintenance samples exceeding TWA-OEL of 1 ppm and the STEL-OEL of 5 ppm were 4.1% (20/488 samples) and 6.0% (13/217 samples), indicating that the proportion of the measurements over the exposure limits in not high. Refinery maintenance workers in petrochemical plants tend to experience intermittent benzene exposures due to a variety of tasks performed over short periods, which may include draining, opening, cleaning, and working on enclosed equipment [34] . The available benzene exposure data reviewed suggests that, although mean full-shift exposures are typically low, higher exposures may occasionally be experienced during shutdown and cleaning procedures, and during irregularly performed maintenance work.…”

Cancer incidence and mortality among temporary maintenance workers in a refinery/petrochemical complex in Korea

“…For example, during the welding of pipelines carrying petroleum, workers may be exposed to chemicals, such as benzene and 1,3-butadiene, and metal fumes containing heavy metals, such as chromium and nickel, and/or asbestos. 1 In Korea, maintenance operations in petrochemical plants are typically performed by temporary employees hired as contract workers. In a regional petrochemical plant maintenance workers union, several cases of leukemias among workers have been reported, raising public concern on the health of maintenance workers in Korea.…”

“…The benzene monitoring study was carried out to assess benzene exposure during turnaround maintenance operations, and the resultant air benzene levels are described in detail elsewhere. 1 This aim of this study was to retrospectively evaluate the cancer risks of temporary maintenance workers in a refinery/petrochemical complex. This is the first study to investigate the cancer risks of petrochemical plant maintenance workers who are primarily engaged in actual maintenance operations.…”