PLYMOUTH – Contamination at the Howe Corner Superfund site on the Sawyer Road in Plymouth cannot be cleaned up, project manager Terry Connelly of the U.S. Environmental Protection Agency told residents Wednesday night.

“It is not technically possible to restore the groundwater,” Connelly said.

Connelly hosted the informational meeting to update residents regarding proposed changes to the site’s remediation plan.

Connelly explained that the 17-acre Superfund site contains two acres of land where landowner George West Jr. of Wells operated a waste oil storage and treatment facility from 1965 to 1980. Thousands of gallons of used oil, degreasers and solvents were dumped on the ground, either accidentally or on purpose, and seeped through bedrock fractures into the groundwater.

More than $6 million has been spent removing contaminated soil and installing the public water system, all of that paid by the businesses and towns that sent oil to the site.

There are 77 parcels of land affected and 53 homes have been connected to the water system.

“The good news is the contamination is limited to the upper 100 feet of the bedrock and will not spread to Plymouth Pond,” Connelly told the nearly two dozen people gathered at the Plymouth Grange Hall.

“The bad news is that it has a low flushing capability. It sticks to the rock and will be there a long, long time,” Connelly said. Without treatment, the groundwater will remain contaminated for the next 400 years, he said.

The EPA’s plan involves the construction of what Connelly called a “containment system,” which is a well and pump house that will extract contaminated groundwater, treat it to acceptable drinking water standards, and then recharge it back into the ground.

Not only will this system cleanse the water, Connelly said, it will shut off the flow of the contaminants through the bedrock.

Residents at the meeting were concerned that the contamination might be spreading.

Connelly reassured them that there is no data that shows any increase in the contamination area. He said wells being used in the area are repeatedly tested and consistently show no change. Also, tests indicate that the contamination level drops off quickly the farther one gets from the actual site.

“The level of contamination has remained essentially unchanged in the last 10 years,” he said. “That contamination has gone as far as it’s going to go.”

Everett Spaulding lives directly across the street from the contamination site. He was worried about the new containment system and how loud it would be.

“I don’t want to listen to that for the next 40 years,” Spaulding said. “It’s very quiet and dark out there and that’s what we like about it.”

Connelly assured Spaulding that the pumping station would be back from the road in an enclosed building and that the EPA would cooperate with residents to make it a quiet, efficient system.

A public hearing on the proposals will be held on June 28, Connelly said.