Air Force To Further Investigate Chemicals At Closed Base.

FILE — The sun sets behind the control tower of the former Loring Air Force Base, Saturday, July 18, 2020, in Limestone, Maine. The Air Force plans to test multiple sites at the former Loring Air Force Base for contamination by so-called forever chemicals. Officials are concerned that PFAS contamination from firefighting foam used on Loring's runway may have spread elsewhere. So far, it has not been found in any drinking water supplies. (AP Photo/David Sharp, File)
FILE — The sun sets behind the control tower of the former Loring Air Force Base, Saturday, July 18, 2020, in Limestone, Maine. The Air Force plans to test multiple sites at the former Loring Air Force Base for contamination by so-called forever chemicals. Officials are concerned that PFAS contamination from firefighting foam used on Loring's runway may have spread elsewhere. So far, it has not been found in any drinking water supplies. (AP Photo/David Sharp, File)

BANGOR, Maine (AP) — The U.S. Air Force plans to test multiple sites at the former Loring Air Force Base for contamination by so-called forever chemicals.

Officials are concerned that PFAS contamination from firefighting foam used on Loring's runway may have spread elsewhere. So far, it has not been found in any drinking water supplies.

A previous analysis showed low levels of PFAS, warranting further investigation, the Bangor Daily News reported.

“Our initial investigation found that 21 of our 22 sites require further investigation,” said Val de la Fuente, chief of the Civil Engineering Center’s Eastern Executive Branch.

Sampling for contamination from firefighting foam began in May and will continue throughout fall. The investigation will include at least 1,300 total samples of groundwater, surface water, soil, sediment and fish in and around the redeveloped Loring Commerce Center.

This cleanup of per- and polyfluoroalkyl substances that's known to cause cancer, birth effects and other health risks will be more challenging than previous petroleum spills and chlorinated solvent leaks because the fire foam residue spread, de la Fuente said.