The Seattle Times
www.seattletimes.com

Gasoline additive found in ground water at 30 sites

by Hal Bernton
Seattle Times staff reporter

Wednesday, October 11, 2000

A gasoline additive may have seeped into ground water at hundreds of sites around the state, with the Puget Sound area at the greatest risk, according to a new study released by the Washington Department of Ecology.

The additive is methyl tertiary-butyl ether, or MTBE, which in recent years has emerged nationally as a major and difficult-to-contain water pollutant. Washington state tests confirmed traces of MTBE in the ground water at 30 sites.

So far, there are no reports of MTBE reaching drinking water in Washington, but the test results "clearly show" a potential risk of such contamination, according to the state report.

"This was basically to give us an idea if it was even there, and we were pretty surprised at the results," said Caitlin Cormier, a spokeswoman for the Ecology Department.

Based on that initial survey, state officials estimate a potential for more than 800 other contaminated sites. Most of them are in areas where old fuel tanks already are known to have leaked other gasoline contaminants.

Nationally, MTBE has seeped into dozens of public drinking-water systems. The chemical, in concentrations as low as 20 to 40 parts per billion, can give drinking water a turpentinelike odor and taste. It is also a potential carcinogen. One of the worst cases of MTBE contamination is in Santa Clara, Calif., where half of the city water supply was fouled by the additive. Those wells are no longer in use.

California and other states with the worst water-pollution problems originally embraced MTBE as a way to create cleaner-burning fuels to fight air pollution. The additive was mixed into gasoline at concentrations of 10 percent to 15 percent.

Earlier this year, citing the widespread water pollution, the Environmental Protection Agency (EPA) ordered a phase out of MTBE use in clean-burning fuels, which are specially formulated for smog-prone areas.

In Washington, MTBE has never been used in clean-burning fuel formulations. But some state refineries used to blend the additive in to boost octane, typically at concentrations of less than 5 percent. Within the past several years, as the water-pollution problems associated with MTBE have come to light, all five regional refineries have stopped using the additive.

"The key point, from my perspective, is we don't have a California-type issue here," said Dan Riley of the Western States Petroleum Association. "There has been some historical (MTBE) use but nowhere near as extensive as in California."

Washington state officials confirm that most of the test results indicate contamination levels well below those in California. But at 15 sites, the MTBE levels in ground water exceeded the 20-parts-per-billion level that triggers an EPA drinking-water advisory. And at the worst site, in Davenport, Lincoln County, in Eastern Washington, the contamination level reached 7,150 parts per billion.

In the Seattle area, state officials tested 49 sites. They found that 10 exceeded the federal drinking-water-advisory levels, with the highest concentration reported at 364 parts per billion. The exact locations of the contaminated sites were not disclosed because of confidentiality agreements between the state and landowners.

Most of the sites are at gasoline stations where underground tanks began to leak after years of use.

State officials say they are changing cleanup regulations to require testing for MTBE at gasoline-spill sites. The state also will enforce a cleanup standard requiring no more than 100 parts per billion in soil and no more than 20 parts per billion in ground water.

"Our main goal is to protect drinking water and therefore prevent human exposures," said Cormier, the Ecology Department spokeswoman.