A drinking water well used by the town of Hinesburg is contaminated with low levels of the gasoline additive, MTBE.
Although the levels are below the threshold considered dangerous for drinking, town officials are eager to clean up the pollution problem.
Hinesburg now plans to join a lawsuit against major oil companies to recover costs for the clean-up.
Methyl tertiary butyl ether (MTBE) was added to gasoline to boost octane performance and to make the fuel burn cleaner.
The problem is that it is highly soluble in water, and can pollute groundwater if an underground gasoline tank springs a leak.
Hinesburg Town Administrator Joe Colangelo said officials learned in 2009 that one of the municipal wells was contaminated. He said about 400 people use the well for drinking.
“The levels detected are fairly low; less than 5 parts per billion, while the state has indicated that up to 40 parts per billion is acceptable in drinking water,” he said. “Nonetheless, we do have a contaminated water supply.”
The selectboard recently voted to engage a Houston, Texas-based law firm that specializes in MTBE cases. Colangelo said the multi-state lawsuit will not be directed against a local gas station or fuel distributor but rather is aimed at national companies that he said knew the additive could pollute ground water.
“It’s kind of similar to almost like the class action suit against the tobacco companies. The oil companies were aware, they knew, that this MTBE could have been easily contaminating ground water but they continued to blend the MTBE in with the gasoline,” he said.
Last spring, a jury in New Hampshire ordered Exxon Mobil to pay the state $236 million to monitor and remediate ground water contaminated with the chemical.
Vermont hasn’t sued the oil companies, but MTBE has affected other public water supplies. Chuck Schwer, a section chief in the hazardous sites clean up program with the state Department of Environmental Conservation, said the additive was banned in Vermont and in many other states in 2007.
“So with the removal of it, we don’t see many new incidents of MTBE problems but there certainly are still effects from existing releases of gasoline that had the additive,” he said.
Schwer said charcoal filtration can remove the chemical, but the systems are expensive. The state has helped install treatment systems for water supplies where MTBE levels exceeded the health standards, using money from the state petroleum clean-up fund. Schwer said MTBE contamination has affected wells in East Clarendon, Hartland and Killington.