Earlier this week President Clinton announced plans to phase out MTBE, or Methyl Tertiary Butyl Ether, a gasoline additive introduced in the early 90s to make gas burn cleaner and reduce smog. It is used in all or parts of 16 states.
MTBE accounts for a third of the gas sold in the United States, much of it in the Northeast. Refiners turned to the additive after the Clean Air Act required gas in areas with serious air pollution to contain at least 2 percent oxygen by weight.
But scientists now say MTBE has spent a decade seeping out of underground gasoline tanks and into drinking water systems.
The U.S. Geological Survey recently estimated as many as 9,000 community water wells in 31 states may be affected because they are close to underground leaking storage tanks.
Some experts believe those numbers are likely to grow
"The bottom line is that 9,000 wells is probably an underestimate,"said the Natural Resources Defense Council 's Erik Olson."Literally millions of people are likely to be exposed every year."
People exposed to MTBE complain mostly of bad-tasting water, strong fumes, headaches and nausea.
But some wonder if MTBE could cause more serious health problems, such as cancer. Scientists don't know because MTBE was never tested before being added to gasoline.
"We simply haven't done the research that we need to be sure that it is innocent. It's the kind of research we would have insisted upon for any new chemical that was coming out on the market," said Dr. Bernard Goldstein of Rutgers University. "We should have insisted on it before we started using it."
On Monday afternoon, Environmental Protection Agency Administrator Carol Browner announced that her agency will seek to "significantly reduce or eliminate" MTBE use under the Toxic Substance Control Act. A government official who spoke on the condition of anonymity said the law allows EPA to ban chemicals "deemed to pose an unreasonable risk to the public or the environment."
A Congressional source said the EPA would seek changes in the Clean Air Act to promote ethanol as MTBE's successor. That 1990 law requires the use of oxygenates, the fuel additives which make gas burn more cleanly.
California, which has more leeway than other states to regulate air pollution, has already decided to ban MTBE use by the end of 2002. State officials have asked the EPA for a waiver from the Clean Air Act's oxygenate requirements so the state doesn't ave to switch to ethanol, which is more expensive than MTBE.
At least one farm state is ecstatic about a switch from MTBE to ethanol. In Nebraska, state Ethanol Board Administrator Todd Sneller said if the corn-based additive became the sole replacement to MTBE, then demand for corn could increase by 400 million bushels a year.
An EPA advisory panel concluded last summer that while current MTBE levels in water are not a health risk, its use should be curtailed dramatically due to potential problems of widespread water pollution. Other MTBE critics claim the additive has been found to be a carcinogen and poses health and environmental risks.
Last year, a coalition of Northeast states said low levels of MTBE were found in 15 percent of the drinking water tested in the Northeast, in most cases in amounts less than two parts per billion. Water begins to pose a health concern and tastes or smells bad at 30 to 70 parts per billion. About one percent of water supplies tested in the Northeast had concentrations above 35 parts per billion.
In August 1997, 178 mobile home park residents in Wilmington, N.C., won a $36 million settlement from Texas-based Conoco when a jury decided the oil company was liable for fraud and negligence in covering up leaks of gasoline containing MTBE. Between mid-1992 and mid-1998, North Carolina toxicologists documented more than 1,000 wells statewide contaminated with MTBE.