Compliance with the OSHA Benzene Permissible Exposure Limit (PEL) at the Gasoline Vapor PEL

Abstract

The purpose of this study was to evaluate the new U.S. Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for gasoline vapor of 300 ppm for adequacy of concurrent compliance with the 1 ppm OSHA PEL for benzene. A PEL for gasoline vapor did not exist until January 1989 (effective September 1989) when OSHA adopted the American Conference of Governmental Industrial Hygienists' gasoline vapor Threshold Limit Value of 300 ppm. In this study, short-term, breathing zone air samples were collected during the winter and summer seasons on a gasoline refueling attendant. The winter gasoline vapor results varied from 0.79 to 734 ppm, while the associated benzene vapor concentrations varied from 0.01 to 2.88 ppm. The summer results for gasoline vapor varied from 1.08 to 266 ppm, and the associated benzene vapor results varied from 0.01 to 2.30 ppm. Benzene vapor concentrations associated with a 300-ppm gasoline vapor level were 1.3 and 2.7 ppm for winter and summer, respectively. Gasoline vapor concentrations of 235 ppm in winter and 109 ppm in summer represented upper limit concentrations at which benzene concentrations did not exceed the OSHA PEL of 1 ppm. These findings were corroborated by other published data on benzene levels in gasoline vapor. This study's results strongly suggest that the ‘new’ gasoline vapor PEL does not provide adequate protection against exposure to benzene exceeding the PEL.