Fuel Oxygenates: Environmental and Health Issues
Oxygenates (e.g., methyl tertiary butyl ether [MTBE], ethanol) are required in gasoline in certain areas of the United States by the 1990 Clean Air Act Amendments and have been used since the 1970s to increase the octane of U.S. gasoline. Concerns have arisen ab out potentially adverse health and environmental impacts of oxygenates, particularly in relation to MTBE contamination of water resources through oxygenated gasoline releases from leaking underground storage tanks and other sources. These concerns stand in contrast with the intended air quality benefits of oxygenates and create some difficult issues for those charged with protecting the environment and public health. To weigh the air and water quality trade-offs as well as other issues posed by oxygenated fuels, adequate scientific information is needed to support quantitative risk assessments and cost-effective risk management efforts. This presentation provides an overview on what is known and what remains to be learned about the relative source contributions, environmental fate, occurrence, exposure, and health effects fo oxygenates, as well as risk management practices. A summary and update on recent evaluations of oxygenates by various organizations will also be provided.