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Objectives: This ecologic study assessed whether there was a change in health status in Alaska in the winter of 1992-93 after the introduction of MTBE in gasoline. Methyl tertiary butyl ether(MTBE) is used as a fuel oxygenate in the United States and in Europe. In the winter of 1992-93 MTBE was added to gasoline in the cities of Fairbanks and Anchorage, Alaska. The program was discontinued in Fairbanks in December, 1992, but continued in Anchorage until February 28, 1993., Methods: Outpatient visits for state employees and dependents (n = approximately 28,000) living in Alaska were compared over three winters by analyzing health insurance claims., Results: Odds ratios were calculated. The odds ratios indicated that the winter of 92-93 was not statistically different from previous winters in numbers of claims for upper respiratory illness, bronchitis, headache, or asthma in either Anchorage or Fairbanks., Conclusion: There was no increase in claims for respiratory illness in either city after introduction of MTBE.

Residents of Fairbanks, Alaska reported health complaints when 15%, by volume, methyl tertiary butyl ether (MTBE) was added to gasoline during an oxygenated fuel program. We conducted an exposure survey to investigate the effect of the program on human exposure to MTBE. We studied 18 workers in December 1992 during the program and 28 workers in February 1993 after the program was suspended. All workers were heavily exposed to motor vehicle exhaust or gasoline fumes. In December, the median post-shift blood concentration of MTBE in the workers was 1.8 micrograms/l (range, 0.2-37.0 micrograms/l), and in February the median post-shift blood concentration of MTBE in the 28 workers was 0.24 micrograms/l (range, 0.05-1.44 micrograms/l; p = .0001). Blood MTBE levels were measurably higher during the oxygenated fuel program in Fairbanks than after the program was suspended.

During a 4-week period in late November and early December 1992, blood samples from individuals exposed to auto emissions derived from oxyfuel were analyzed. Effects on the immune system were measured by monitoring plasma interleukin 6 (IL-6) levels in a total of 22 subjects at the beginning and the end of the workday. After approximately 8 h of workplace exposure, mean levels of IL-6 of 2.5 pg/ml were obtained. While some subjects showed increasing levels at the end of the workday, there was no difference between morning and evening IL-6 means. Our conclusion is that single day exposures to oxyfuel and its combustion products does not show an immediate effect on the immune system as judged by serum IL-6 levels.