EXPOSURE TO METHYL TERT-BUTYL ETHER AND BENZENE AMONG SERVICE STATIONATTENDANTS AND OPERATORS

Concerns for atmospheric pollution from auto exhaust have led to the b lending of ''oxygenates'' with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is curl-entry required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the mot or fuel. Amendments to the Clean Air Act may expand this requirement t o as many as 44 other areas of the United States in the near future. I n consideration of the magnitude of potential uncontrolled exposures f rom its extensive use and a related concern involving the potential in fluence of MTBE blending on exposures to other constituents of gasolin e (particularly benzene), an evaluation of exposures among service sta tion attendants and operators was undertaken at the request, and in co operation with, the American Petroleum Institute during the latter par t of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with reg ard to MTBE use and exposure potential: a) service stations that do no t use MTBE or use it only as an octane enhancer, b) service stations w ith seasonal requirements to use 12-15% MTBE (the Denver, Colorado, an d Phoenix, Arizona, metropolitan areas), and c) service stations equip ped with stage II (active) vapor recovery systems (several coastal are as, most notably Southern California). At the two sampled service stat ions that use only minimal amounts of MTBE (less than 1%) only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the a nalytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm. At the two sampled stations with requirements to use oxygenated fuel, geometric mean MTBE and benzene concentrations were 0.30 and 0.0 4 ppm, respectively (n = 41). At the two stations equipped with stage II vapor recovery, 16 of 48 PBZ samples for MTBE were detectable, with a geometric mean concentration of 0.09 ppm. The geometric mean benzen e concentration at these facilities was 0.06 ppm (n = 48).