MONTPELIER -- Vermont is suing more than two dozen oil companies to recover the ongoing costs to clean up preventable groundwater contamination.

Among the companies the state is suing are BP, Chevron, Exxon Mobil Corp. and Shell. The state alleges that these companies used the toxic gasoline additive, MTBE (methyl tertiary-butyl ether), knowing that it "posed a devastating risk" to the state's water supplies.

"We believe these companies knew years ago that MTBE was a uniquely bad actor in groundwater, and they ignored the risks and sold it anyway," said Attorney General Bill Sorrell in a statement last week. "This lawsuit is about holding them accountable and ensuring that they -- and not Vermonters -- pay to clean up our groundwater.

Vermont AG William Sorrell. (VTD/Josh Larkin)
Vermont AG William Sorrell. (VTD/Josh Larkin) (Josh Larkin)
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MTBE quickly spreads through groundwater when it spills or leaks from underground tanks. Vermont alleges oil companies should have known "MTBE contamination of groundwater and drinking water was inevitable."

The gasoline additive is now banned in Vermont. Nonetheless, the state continues to clean up and find wells contaminated decades ago.

"The companies that profited from selling MTBE need to be held responsible for the resulting damage to our groundwater," said Environmental Conservation Commissioner David Mears in the statement. "Vermont citizens deserve compensation so that we can invest in restoring this vital source of clean water."

Chuck Schwer, site cleanup program manager for the Department of Environmental Conservation, said in an interview the state has cleaned up more than 2,000 leaks. More than three-quarters of these leaks contained MTBE, he said. In the past six years, Schwer said the state has paid $24 million to clean this up.

"As long as we we're aware of the problem, our program has been very proactive," he said. This includes installing charcoal filtration systems and providing bottled water to residents.

One of the worst cases was a 1992 tank leak in Killington that contaminated over 40 wells. The state is still paying to treat the groundwater and provide bottled water.

The toxic gasoline additive was designed to improve air quality under the federal Clean Air Act. But now, oil companies have paid billions to state, cities, and individuals to clean up and settle cases of water contamination. A New Hampshire jury last year ordered Exxon Mobil to pay $236 million in for similar damages to the state's water quality.

"The Environmental Protection Agency (EPA) certified MTBE for Clean Air Act compliance twice and refiners then used the product as a gasoline additive to comply with federal mandates," the trade group American Fuel and Petrochemical Manufacturers said in an emailed statement Monday.

"In the State of Vermont (and every other state in the country), if you spill gasoline, you are required to clean it up. If plaintiffs are determined to correct a problem that does not exist, we suggest that the solution lies at EPA, which approved the use of MTBE not once, but twice. This case, and similar cases elsewhere, should be dismissed as it makes absolutely no sense to penalize refiners for blending an oxygenate such as MTBE to comply with a government fuel mandate. Yet again we see the consequences of such ill-informed policies," the group wrote.