International Journal of Hygiene and Environmental Health 213 (2010) 285–301 Contents lists available at ScienceDirect International Journal of Hygiene and Environmental Health journal homepage: www.elsevier.de/ijheh Occupational exposure to benzene at the ExxonMobil refinery in Beaumont, TX (1976–2007) Shannon H. Gaffney a,* , Amanda M. Burns b , Marisa L. Kreider b , Ken M. Unice b , Thomas E. Widner a , Dennis J. Paustenbach a , Lindsay E. Booher c , Richard H. Gelatt d , Julie M. Panko b a ChemRisk, LLC, 25 Jessie St., Suite 1800, San Francisco, CA, USA b ChemRisk, LLC, Pittsburgh, PA, USA c ExxonMobil Production Company, Houston, TX, USA d ExxonMobil Biological Sciences, Annandale, NJ, USA article info Article history: Received 16 November 2009 Received in revised form 10 April 2010 Accepted 14 April 2010 Keywords: Benzene Refineries Exposure assessment Industrial hygiene abstract Because crude oil and refined petroleum products can contain benzene and benzene is considered a known carcinogen by numerous independent and governmental agencies, including the International Agency for Cancer Research, the petroleum industry has implemented exposure control programs for decades. As part of the benzene control programs, significant exposure assessments have been performed; both qualitatively and through quantitative measurements. In this study, we evaluated the airborne concentrations of benzene and their variability over time at the ExxonMobil refinery in Beaumont, TX between 1976 and 2007. The results of 5854 personal air samples are included in this analysis; 3761 were considered non-task (≥180 min) personal samples, and 2093 were considered task-related (<180 min) personal samples. Dock and loading rack samples were analyzed separately from the refinery samples because in addition to refinery products, employees at the dock and loading rack also handled chemical plant products. In general, the non-task personal refinery air samples indicated that exposures of the past 30 years were generally below the occupational exposure limit of 1 ppm (mean = 0.30 ppm, SD = 3.1), were higher during routine (mean = 0.32 ppm, SD = 3.3) than turnaround operations (mean = 0.16 ppm, SD = 0.87), and decreased slightly over time. The job sampled most frequently during routine operations was that of process technician, and, as broken down by area, resulted in the following mean benzene air concentrations: coker (n = 146, mean = 0.014 ppm, SD = 0.036), lube extraction unit (n = 31, mean < 0.070 ppm), pipestills (n = 136, mean = 0.12, SD = 0.47), waste treatment (n = 107, mean = 0.20, SD = 0.28), and all other areas (n = 1115, mean = 0.059 ppm, SD = 0.36). Task-based samples indicated that the highest exposures resulted from the tank cleaning tasks, although the overall task mean benzene air concentration was 1.4 ppm during routine operations. The most frequently sampled task during routine operations was blinding and breaking, and the mean benzene air concentrations associated with this task were statistically higher in the reformer area of the refinery (n = 311, mean = 3.2 ppm, SD = 7.9) than in all other areas (n = 200, mean = 0.92 ppm, SD = 3.1). However, task-related exposures were found to be statistically similar across job categories for a given task. This study thus provides a task-focused analysis for occupational exposure to benzene during refinery operations, and will be useful for understanding exposures at this refinery. © 2010 Elsevier GmbH. All rights reserved. Introduction Benzene is found in refinery process streams as a result of its presence in crude oil, and as a byproduct of refining operations (IARC, 1988; WHO, 1993; U.S. EPA, 1998; Verma and des Tombe, 1999; van Wijngaarden and Stewart, 2003). Although the refin- ing process is considered to be “closed and continuous,” periodic * Corresponding author. E-mail address: sgaffney@chemrisk.com (S.H. Gaffney). operational and maintenance activities result in the opening of equipment and, as such, increased potential for exposure to refin- ery process streams (OSHA, 2003). Consequently, monitoring of occupational exposures to benzene in employees of the petroleum refining industry has been ongoing for more than 60 years to iden- tify these activities and control corresponding potential exposures. Furthermore, because of benzene’s known associated adverse health effects, regulations have been promulgated to reduce the amount of benzene to which workers and the general public are exposed (U.S. EPA, 1990). Published reports of benzene exposures during refining operations indicate that full-shift exposures have 1438-4639/$ – see front matter © 2010 Elsevier GmbH. All rights reserved. doi:10.1016/j.ijheh.2010.04.004