The exposure of service station attendants and operators to methyl- tert-butyl-ether (1634044) (MTBE) and benzene (71432) was investigated. Service attendants with at least one full service island, and three categories of service (stations that did not use MTBE (Cincinnati, Ohio), those that had seasonal requirements to use 12% to 15% MTBE (Phoenix, Arizona), and those equipped with active vapor recovery systems (Los Angeles, California). Sampling consisted of about 60 shifts, two samples/shift. Personal air samples of one per 4 hour (hr) or two per 8hr shift were collected. Results from 27 Cincinnati samples showed MTBE contents of 0.03 to 0.13% liquid volume (LV%), with average benzene ranging from 0.39 to 0.86LV%. Highest MTBE and benzene contents were from regular grade gasoline (0.18 and 1.60 LV%, respectively). Average MTBE in Phoenix was much higher (1.18 to 1.63 LV%), while those in Los Angeles were 2.10 LV%. Benzene levels in Los Angeles were 1.76 to 2.00 LV%. MTBE and benzene exposure variations by location were calculated. Only one of 32 samples for MTBE was above the analytical limit of detection in Cincinnati at 0.16 parts per million (ppm). In Phoenix, where MTBE content averaged 12.5 to 13%, exposures averaged 0.30ppm. In Los Angeles, MTBE exposures averaged 0.14ppm. Higher MTBE exposures were correlated with the service station distributing premium grade fuel containing 11 LV% MTBE. Benzene exposures averaged 0.03ppm in Cincinnati, 0.05ppm in Phoenix, and 0.06ppm in Los Angeles. The author concludes that the average exposure to MTBE among service station attendants is below 1ppm, when at least 12% MTBE is used in fuels, and that this does not seem to affect benzene exposure patterns.