Assessment of Occupational Methyl Tertiary Butyl Ether Vapor Exposures to Petroleum Refinery and Transport Loading Rack Facility Employees

Abstract

Abstract The use of oxygenated gasoline is required for metropolitan areas which exceed the carbon monoxide nonattainment standard as specified by the Clean Air Act Amendments of 1990. Many petroleum refineries blend methyl tertiary butyl ether (MTBE) with gasoline to make oxygenated fuel, which burns cleaner and reduces carbon monoxide emissions from motor vehicle exhaust. MTBE has a low acute toxicity ranking and is only mildly irritating to the eyes and skin. Excessive acute vapor inhalation causes depression of the central nervous system. Limited animal data indicate that MTBE may increase the risk of cancer, although this has not been adequately addressed. This assessment was conducted to monitor airborne MTBE occupational exposure to petroleum refinery and transport loading rack facility employees at one location. The 47 time-weighted average (TWA) and short-term exposure limit (STEL) personal air samples collected did not exceed the American Industrial Hygiene Association workplace environmental exposure level of 100 ppm for an 8-hour TWA. The 38 personal STEL samples collected ranged from <0.896 to 35.012 ppm with a geometric mean of 2.44 ppm. The nine personal TWA samples ranged from <0.042 to 1.750 ppm with a geometric mean of 0.58 ppm. This study found that minimal occupational exposures to MTBE occurred when fugitive emissions from operating equipment were limited, leaks and spills during product transfer were minimized, and mechanical equipment was thoroughly depressurized and purged before allowing the equipment to be repaired.