MTBE (methyl tertiary-butyl ether) is a chemical compound that is manufactured through 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.
MTBE has been used in U.S. gasoline at low levels since 1979 to replace lead
as an octane enhancer (helps prevent the engine from "knocking"). Since 1992, MTBE has been used at higher concentrations in some gasoline to fulfill the oxygenate requirements set by Congress in the 1990 Clean Air Act Amendments. (A few cities, such as Denver, used oxygenates (MTBE) at higher concentrations during the wintertime in the late 1980's.)
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.
The majority of the human health-related research conducted to date on MTBE has focused on effects associated with the inhalation of the chemical. When research animals inhaled high concentrations of MTBE, some developed cancers
or experienced other non-cancerous health effects. However, researchers have limited data about what the health effects may be if a person swallows MTBE. EPA's Office of Water has concluded that available data are not adequate to estimate potential health risks of MTBE at low exposure levels in drinking water but that the data support the conclusion that MTBE is a potential human carcinogen at high doses. Recent work by EPA and other researchers is expected to help determine more precisely the potential for health effects from MTBE in drinking water.
See your doctor if you have experienced serious health problems because of MTBE exposure. In addition, it may be important to contact an attorney
who can help you protect your legal rights. Please keep in mind that there may be time limits
within which you must commence suit.
Some information provided by the Agency for Toxic Substances and Disease Registry
- Toxic & Hazardous Substances
- MTBE Exposure: Frequently Asked Questions