The U.S. Environmental Protection Agency has added a groundwater contamination plume in Goshen threatening the city’s water supply to the Superfund National Priorities List, a list of the most contaminated sites in the U.S.

The North 5th Street Groundwater Contamination site and 11 other contaminated sites across the nation were added to the list, which serves as the basis for prioritizing EPA Superfund cleanup funding and enforcement actions, according to the agency.

The site is contaminated with a 15.1-acre plume of cis-1,2-dichloroethylene and vinyl chloride, two chlorinated solvents that can cause liver and lung damage with prolonged exposure.

According to the EPA, the solvents have been detected in four of Goshen’s municipal groundwater wells at levels below the Safe Drinking Water Act maximum contaminant level.

The contamination affects the city’s raw water, the untreated water that makes its way to the city’s water treatment plant. The water is then treated, tested and distributed.

“Today’s addition of the North 5th Street Groundwater Contamination site to the NPL demonstrates our commitment to protect communities in Goshen living near the groundwater contamination,” said EPA Region 5 Administrator Debra Shore. “We will continue to build a better America by working with our state and local partners to use our federal resources to clean up this site.”

The solvents were first detected in trace amounts in 1993, but the Indiana Department of Environmental Management found increased amounts in 2016.

The agency investigated, finding more solvents and identifying 67 commercial and industrial facilities within one mile of the site that could be the source of the contamination. Ultimately, IDEM was unable to find the definitive source.