The U.S. Department of Defense plans to install two more groundwater treatment systems at a former Michigan military base to control contamination from so-called forever chemicals, U.S. Rep. Elissa Slotkin’s office announced Friday.

Environmentalists say the systems will help prevent PFAS from spreading into the Clarks Marsh area and the Au Sable River near the former Wurtsmith Air Force Base in Oscoda on the shores of Lake Huron. The base closed in 1993 as part of a base realignment.

PFAS, an abbreviation for perfluoroalkyl and polyfluoroalkyl substances, are compounds that don’t degrade in the environment. They’re linked to a host of health issues, including low birthweight and kidney cancer. The chemicals are found in a wide range of products, including nonstick cookware, food packaging and firefighting foam that airports use to combat fires resulting from plane crashes.

Pentagon documents show at least 385 military bases nationwide are contaminated with PFAS, mostly from firefighting foam used during training.

DOD records released in 2021 showed PFAS had been detected in groundwater around Wurtsmith at levels up to 213,000 parts per trillion. Federal regulators in March proposed limits of 4 parts per trillion in drinking water. State officials have warned people not to eat fish, venison or small game caught in and around Clarks March and parts of the Au Sable and to avoid contact with all surface water and shoreline foam in Oscoda.

The Department of Defense announced in August that it would install two groundwater treatment systems near the base. The two new systems would be in addition to those systems.

“This announcement is a milestone moment for Oscoda and its surrounding communities,” Slotkin said in a news release. “I will continue to urge the Pentagon to swiftly implement these measures and to address other instances of PFAS contaminations at installations in Michigan and across the country.”

Tony Spaniola, co-chair of the Great Lakes PFAS Action Network, has pushed the Pentagon to clean up PFAS contamination around Wurtsmith since he was notified in 2016 that water near his Oscoda cabin wasn’t safe to drink. In a statement in Slotkin’s news release, he called the additional systems “a landmark moment.” The effort should serve as a model for cleanup at other contaminated military installations, he said.