TRAVERSE CITY, Mich. — High levels of toxic, widely used “forever chemicals” contaminate groundwater around at least six military sites in the Great Lakes region, according to U.S. Department of Defense records that an environmental group released Tuesday.

The Environmental Working Group said PFAS, an abbreviation for perfluoroalkyl and polyfluoroalkyl substances, have oozed into the Great Lakes and pose a risk to people who eat fish tainted with the chemicals.

Pentagon documents show at least 385 military installations nationwide are polluted with PFAS, mostly from firefighting foam used widely in training exercises, the group said.

“If you are relying on well water and are near one of these bases where PFAS has been confirmed in the groundwater, you should be concerned,” said Scott Faber, senior vice president of government affairs. “And you should be doubly concerned if you are near one of the hundreds of bases where PFAS is suspected but not confirmed.”

Asked for comment, a Pentagon spokesman referred to remarks by Richard Kidd, deputy assistant secretary of defense for environment and energy resilience, during a July 14 public discussion on PFAS. Kidd said it would take “years to fully define cleanup requirements the department faces, and probably decades before that cleanup is complete.”

“We are intent on making sustained progress on all PFAS challenges,” Kidd said, adding that cleanup costs were estimated at $2 billion.

A review of department records showed PFAS has been detected at levels up to 213,000 parts per trillion at the former Wurtsmith Air Force Base in Oscoda, Michigan, which closed in 1993, the Environmental Working Group said.

State officials discovered the contamination in 2010. The Air Force is treating PFAS-contaminated groundwater at some sites in the area, but local residents and members of Congress have called the actions insufficient and demanded a stronger and faster approach.

The environmental group said its study turned up high readings at five other Great Lakes bases.

Combined levels of PFOA and PFOS, two of the most commonly used chemicals in the group, reached as high as 1.3 million ppt at Niagara Falls Air Reserve Station in Niagara County, New York.

Other readings included 135,000 ppt of the compound PFHxS at General Mitchell International Airport in Milwaukee; 82,000 ppt of PFOA and PFOS at Alpena County Regional Airport in Michigan; 17,000 ppt of PFOS at Selfridge Air National Guard Base in Mount Clemens, Michigan; and 5,400 ppt of PFHxS at Duluth International Airport in Minnesota.

Most civilian airports also have firefighting foam containing PFAS and some have released it to the environment during emergency fire suppression and training, said Melanie Benesh, the group’s legislative attorney. Federal regulations require that airports be equipped with foams meeting military specifications, although Congress has ordered the Federal Aviation Administration to allow foams without PFAS.

The Biden administration is developing national standards for triggering PFAS cleanups in drinking water and groundwater. The Environmental Protection Agency presently has a non-enforceable health advisory level of 70 ppt for PFOS and PFOA for drinking water.

PFAS compounds, first developed in the 1940s, are used in a variety of commercial and household products ranging from non-stick cookware to food packaging and water-repellent clothing. Foam containing PFAS has long been used to extinguish jet fuel fires.

The compounds are called “forever chemicals” because they don’t break down in the environment or the human body and can accumulate over time. They have been linked to a variety of health problems including cancer, liver damage and decreased fertility.