| Controlled Human Exposure to Methyl Tertiary Butyl Ether in Gasoline: Symptoms, Psychophysiologic and Neurobehavioral Responses of Self-Reported Sensitive Persons Nancy Fiedler,1,2 Kathie Kelly-McNeil,1,2 Sandra Mohr,1,2 Paul Lehrer,1 Richard E. Opiekun,1,2 ChiaWei, Lee,1,2 Tom Wainman,1,2 Robert Hamer,1 Clifford Weisel,1,2 Robert Edelberg,1,2 and Paul J. Lioy1,2 1UMDNJ-Robert Wood Johnson Medical School, Department of Environmental and Community Medicine, Piscataway, New Jersey, USA
2Environmental and Occupational Health Sciences Institute, Piscataway, New Jersey, USA. Abstract
The 1990 Clean Air Act mandated oxygenation of gasoline in regions where carbon monoxide standards were not met. To achieve this standard, methyl tertiary butyl ether (MTBE) was increased to 15% by volume during winter months in many locations. Subsequent to the increase of MTBE in gasoline, commuters reported increases in symptoms such as headache, nausea, and eye, nose, and throat irritation. The present study compared 12 individuals selected based on self-report of symptoms (self-reported sensitives ; SRSs) associated with MTBE to 19 controls without self-reported sensitivities. In a double-blind, repeated measures, controlled exposure, subjects were exposed for 15 min to clean air, gasoline, gasoline with 11% MTBE, and gasoline with 15% MTBE. Symptoms, odor ratings, neurobehavioral performance on a task of driving simulation, and psychophysiologic responses (heart and respiration rate, end-tidal CO2, finger pulse volume, electromyograph, finger temperature) were measured before, during, and immediately after exposure. Relative to controls, SRSs reported significantly more total symptoms when exposed to gasoline with 15% MTBE than when exposed to gasoline with 11% MTBE or to clean air. However, these differences in symptoms were not accompanied by significant differences in neurobehavioral performance or psychophysiologic responses. No significant differences in symptoms or neurobehavioral or psychophysiologic responses were observed when exposure to gasoline with 11% MTBE was compared to clean air or to gasoline. Thus, the present study, although showing increased total symptoms among SRSs when exposed to gasoline with 15% MTBE, did not support a dose-response relationship for MTBE exposure nor the symptom specificity associated with MTBE in epidemiologic studies. Key words: controlled exposure, methyl tertiary butyl ether, neurologic, psychophysiology, self-reported sensitives, symptoms. Environ Health Perspect 108:753-763 (2000) . [Online 28 June 2000] http://ehpnet1.niehs.nih.gov/docs/2000/108p753-763fiedler/ abstract.html Address correspondence to N. Fiedler, Environmental and Occupational Health Sciences Institute, UMDNJ-Robert Wood Johnson Medical School, 170 Frelinghuysen Road, Room 210, Piscataway, NJ 08854 USA. Telephone: (732) 445-0123, ext. 625. Fax: (732) 445-0130. E-mail: nfiedler@eohsi.rutgers.edu We thank the participants who volunteered for the study, the Scientific Advisory Committee for its comments, and D. Ashley of the Centers for Disease Control for quality assurance analyses of blood data. Funding was provided by ARCO (now Lyondell) and the New Jersey Department of Environmental Protection. N. Fiedler, C. Weisel, S. Mohr, and P. Lioy are supported, in part, by NIEHS Environmental Health Center grant ES05022-12. Received 31 January 2000 ; accepted 11 April 2000.
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