Benzene is a known carcinogen and long term exposure to this chemical may result in leukemia. The Occupational Safety and Health Adminstration (OSHA) permissible exposure limit (PEL) for benzene, established in the 1980’s, was 1 ppm. In the 1980’s, tetra ethyl lead, an octane booster, was removed from gasoline and replaced with these aromatic hydrocarbons: Benzene, Toluene, Ethylene and Xylene (BTEX). In 1990, benzene was one of 189 hazardous air pollutants (HAPS) identified by the Environmental Protection Agency (EPA) in the Clean Air Act of 1990. As a result, the quantity of benzene in gasoline was gradually reduced to limit the benzene emitted to the atmosphere. In 2015, EPA announced a plan to regulate benzene at 2.8 ppb at the fenceline of refineries and chemical plants since neighbors of these facilities could experience exposure to low levels of benzene in the ambient air for 24 hours per day.
The OSHA limits (PEL = 1.0 ppm) for the workplace (chemical plants, gas pipelines, shipyards etc.) can be measured at the 1 ppm level using a portable gas chromatograph configured with a photoionization detector (GC/PID). The EPA limit of 2.8 ppb at refinery
and chemical plants fence lines is near the detection limits for most GC/PID’s so a low power concentrator would be needed to measure sub ppb levels of benzene without interference from hexane or other alkanes present. A new mini hand-held GC based analyzer that will be able to measure benzene in the workplace at ppb levels and at ppt levels in refinery and chemical plant fencelines will be described.