Benzene and Total Hydrocarbons Exposures in the Downstream Petroleum Industries

Abstract

A review of studies, including both articles published in peer-reviewed journals and reports that were not peer reviewed, regarding occupational exposure to benzene and total hydrocarbons in the downstream petroleum industry operations was performed. The objective was to provide a broad estimate of exposures by compiling exposure data according to the following categories: refinery, pipeline, marine, rail, bulk terminals and trucks, service stations, underground storage tanks, tank cleaning, and site remediations. The data in each category was divided into personal occupational long-term and short-term samples. The summarized data offers valuable assistance to hygienists by providing them with an estimate and range of exposures. The traditional 8-hour time-weighted average (TWA) exposure and the 40-hour workweek do not generally coincide with exposure periods applicable to workers in marine, pipeline, railcar, and trucking operations. They are more comparable with short-term exposure or task-based exposure assessments. The marine sector has a large number of high exposures. Although relatively few workers are exposed, their exposures to benzene and total hydrocarbons are sometimes an order of magnitude higher than the respective exposure limits. It is recommended that in the future, it would be preferable to do more task-based exposure assessments and fewer traditional TWA long-term exposure assessments within the various sectors of the downstream petroleum industry.

Occupational exposure to benzene at the ExxonMobil Refinery in Baytown, TX (1978–2006)

“…These findings are similar to data from other refinery studies, and demonstrate that the nature of the work being performed is a major determinant of overall exposure to benzene (Verma et al, 2001). However, because there are often very few samples associated with a job category and area, the absence of any statistical difference may be a function of a small sample size.…”

“…Air concentrations of benzene collected while performing specific jobs and tasks were found to be consistent with the results reported in other studies of benzene exposure in the petroleum industry (Weaver et al, 1983;Buchet et al, 1984;Runion and Scott, 1985;CONCAWE, 1987CONCAWE, , 1994Nordlinder and Ramnas, 1987;Rappaport et al, 1987;HEI, 1988;Verma et al, 2001). When comparing the results of this study to the industry-wide data sets, the average exposures at the Baytown refinery decrease within the range of those reported in the literature, despite the fact that the Baytown data set was targeted to over-represent benzene handling activities (Verma et al, 2001). The average benzene air concentration at the Baytown refinery for all non-task samples is 0.23 p.p.m.…”

“…The average benzene air concentration at the Baytown refinery for all non-task samples is 0.23 p.p.m. (during routine operations), compared with the arithmetic means reported in the literature, which range from 0.05 to 1.62 p.p.m., with an Exposures to benzene at refineries Gaffney et al (Runion and Scott, 1985;Verma et al, 2001). Fifty-nine percent of the non-task samples showed benzene air concentrations below the LOD.…”

“…Existing literature reporting benzene exposures during refining operations indicate that full-shift exposures have been typically less than 1 part per million (p.p.m.) since the 1980s (Weaver et al, 1983;Buchet et al, 1984;Runion and Scott, 1985;CONCAWE, 1987CONCAWE, , 1994Nordlinder and Ramnas, 1987;Rappaport et al, 1987;HEI, 1988;Glass et al, 1994Glass et al, , 2000Glass et al, , 2001Armstrong et al, 1996;Verma et al, 2001). Although these studies provide useful information regarding potential occupational exposures to benzene in the petroleum industry, they do not provide detailed job-or task-specific exposure data or information specific to workers at individual facilities.…”

Airborne concentrations of benzene for dock workers at the ExxonMobil refinery and chemical plant, Baton Rouge, Louisiana, USA (1977–2005)

“…The analysis by task bin is unique to this study, as other dock worker studies have focused primarily on long-term exposure estimates. Although using task-based exposure levels in epidemiology has its limitations (34), Verma et al (35) summarized data from several studies evaluating benzene exposure to employees in petroleum industries and explicitly recommended moving towards task-based exposure assessments as opposed to long-term time-weighted average estimates for the petroleum industry. This study addresses Verma et al's recommendation by providing a detailed task-level analysis of benzene air concentrations at the Baton Rouge docks.…”