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Environmental Health - Toxic Substances



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Methyl tertiary butyl ether (MTBE) - "MTBE is an oxygenate added to gasoline to improve combustion and to reduce harmful vehicle emissions." - Moran and others, 2006

Methyl tertiary butyl ether (MTBE) - "MTBE is used as a gasoline additive for several purposes. It has been added in relatively low concentrations to increase octane ratings in premium grade fuels since the late 1970's. Beginning in the early 1990's MTBE has been added in much higher concentrations (up to 15 percent) to enhance gasoline combustion and reduce tailpipe emissions ... MTBE is the most common fuel oxygenate, used in more than 80 percent of oxygenated fuels. MTBE is credited with contributing to significant reductions in carbon monoxide and ozone levels in many of these areas." - U.S. Geological Survey, 2007

Methyl tertiary butyl ether (MTBE) - "A chemical compound that is manufactured by the chemical reaction of methanol and isobutylene. MTBE is produced in very large quantities (over 200,000 barrels per day in the U.S. in 1999) and is almost exclusively used as a fuel additive in motor gasoline. It is one of a group of chemicals commonly known as "oxygenates" because they raise the oxygen content of gasoline. At room temperature, MTBE is a volatile, flammable and colorless liquid that dissolves rather easily in water ... A growing number of studies have detected MTBE in ground water throughout the country; in some instances these contaminated waters are sources of drinking water. Low levels of MTBE can make drinking water supplies undrinkable due to its offensive taste and odor." - U.S. Environmental Protection Agency, 2008

MTBE - "Oxygenates, compounds that contain oxygen, are commonly added to gasoline in the United States (U.S.) as an octane enhancer and to promote more complete combustion of gasoline ... the oxygenate used most commonly is methyl tert-butyl ether (MTBE) because of its low cost, ease of production, and favorable transfer and blending characteristics (Squillace and others, 1995)." - Squillace and Moran, 2000

MTBE - "MTBE often is added to gasoline at up to 15 percent by volume ... MTBE has a foul odor, and when it contaminates drinking water supplies it can render the water unusable. MTBE is generally resistant to biodegradation because of its stable molecular structure and its reactivity with microbial membranes." - National Research Council, 2000

Related Definitions

Fuel Oxygenates


Volatile Organic Compounds (VOCs)

BTEX (benzene, toluene, ethylbenzene, xylene)

USGS Information on MTBE

Related Science Feature Articles

Other Information on MTBE


Moran, M.J., Hamilton, P.A., and Zogorski, J.S., 2006, Volatile organic compounds in the Nation's ground water and drinking-supply wells--A summary: U.S. Geological Survey Fact Sheet 2006-3048, 6 p.

National Research Council, 2000, Natural attenuation for groundwater remediation: Washington, D.C., National Academies Press, 274 p.

Squillace, P.J., and Moran, M.J., 2000, Estimating the likelihood of MTBE occurrence in drinking water supplied by ground-water sources in the Northeast and Mid-Atlantic regions of the United States: U.S. Geological Survey Open-File Report 00-343, 16 p.

Squillace, P.J., Pankow, J.F., Korte, N.E., and Zogorski, J.S., 1996, Environmental behavior and fate of methyl tert-butyl ether (MTBE): U.S. Geological Survey Fact Sheet 203-96, 6 p.

Squillace, P.J., Pope, D.A., and Price, C.V., 1995, Occurrence of the gasoline additive MTBE in shallow ground water in urban and agricultural areas: U.S. Geological Survey Fact Sheet 114-95, 4 p.

U.S. Environmental Protection Agency, 2008, Methyl tertiary butyl ether (MTBE) overview: U.S. Environmental Protection Agency, access date August 11, 2010.


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