The Maine Air National Guard’s base of operations at Bangor International Airport sits atop groundwater tainted with high levels of toxic, so-called forever chemicals that seeped into it from decades of the guard using firefighting foam on the property.
A report published by the U.S. Air Force last month says there’s a high risk that the contamination from those chemicals, called PFAS, has spread beyond the base property, which could contaminate area water supplies.
But the military branch is in the middle of a long process of figuring out how widespread the contamination is, and how to address it.
The findings stem from work the Department of Defense has started over the past two decades to identify the military properties where a specific type of firefighting foam made with PFAS, Aqueous Film Forming Foam, was used.
The analysis of the Air National Guard site in Bangor — home to the 101st Air Refueling Wing — is part of an effort by the Air Force that started around 2015 to look at each of its National Guard bases to determine if the foam was used there, said Jenna Laube, an engineer who manages environmental cleanup sites for the U.S. Air Force.
The findings from the Air Force’s analysis of the site, which is owned by the city of Bangor, provide one more piece of the puzzle as Maine comes to grips with the extent of contamination from PFAS, which have been used for decades in manufacturing and were common in firefighting foam that was heavily used on military properties starting in the 1970s.
The chemicals have been linked to a number of health problems, and state and federal governments have been working on expanded testing for the chemicals and setting new safety thresholds for drinking water.
“The EPA and regulations are still kind of a moving target. They’re still trying to figure out the data,” Laube said. “But since we knew it was emerging as a contaminant, we started looking into it a number of years ago.”
As part of the process, the Air Force made a list of facilities that used the firefighting foam and those that didn’t, then set out to identify individual locations on bases that may have seen the most foam use.
The Air Force’s site investigation of the Bangor base in 2018 found nine locations where the toxic foam had been widely used for a variety of purposes — to clean up fuel spills, for regular firefighter trainings and for routine testing of the base’s emergency systems.
Groundwater samples taken from those locations contained both PFOS and PFOA — two varieties of chemicals — at levels hundreds of times higher than the EPA’s safe drinking water threshold for PFAS.
And there’s a good chance the contamination has spread beyond the Air National Guard base’s grounds, including to nearby residential wells.
“Overall, Bangor has a lot of high-potential release locations,” Laube said.
One groundwater sample from a spot on the base where there’s a nozzle that releases the firefighting foam was revealed to have 11,700 parts PFOS per trillion parts water. That’s 585 times higher than Maine’s interim safe drinking water standard of 20 parts per trillion.
The Air Force’s investigations into its national guard sites are showing that more sites are contaminated than not, especially sites that had aircraft, Laube said.
Bangor’s water quality director, Amanda Smith, said the results aren’t surprising and that she expects additional testing will show more PFAS contamination.
“Firefighting foam was among the first identified sources of these chemicals,” she said. “It is also prohibited from entering the sewer system.”
The Air Force has also been investigating possible PFAS contamination at the site of the former Loring Air Force Base in the Aroostook County town of Limestone.
In Bangor, the Air Force is still working to understand just how widespread the contamination is, Laube said.
“We know that there is an on-base existence of PFAS,” she said. “We don’t know what those impacts mean yet.”
Maj. Carl Lamb, a spokesperson for the Maine National Guard, said the risk evaluation is an important step toward eventual remediation of the problem, whatever form that remediation takes.
“While there are no drinking wells on base in Bangor, AFFF foam was previously used and tested there, and [101st Air Refueling Wing] staff have been diligently following the steps in accordance with the DOD process,” Lamb said.