Initial state tests reveal extremely high concentrations of an especially long-lasting and toxic forever chemical at Brunswick Landing, where a malfunction in an airport hangar’s fire suppression system created one of the country’s biggest firefighting foam spills in 30 years.

The tests found 3.2 billion parts per trillion of perfluorooctane sulfonic acid, or PFOS, in the chemical tank that fed 1,450 gallons of aqueous film-forming foam (AFFF) concentrate into a malfunctioning fire suppression system at Hangar 4 at Brunswick Executive Airport on Aug. 19.

To put that into context, Maine has established several screening guidelines for remedial action when it comes to PFOS – 1,000 parts per trillion for groundwater leachate, 210 parts per trillion for milk and 20 parts per trillion for PFOS alone or in combination with five other forever chemicals that are part of the manmade PFAS (perfluorinated alkylated substance) group.

The new federal drinking water standard for PFOS is even stricter: no more than 4 parts per trillion.

PFOS wasn’t the only forever chemical found in the concentrate mix released in Hangar 6, but it was the primary one, according to the test results from the Maine Department of Environmental Protection. The property manager said the tank was filled with Chemguard and Ansulite, two commercial formulations.

About 7,500 gallons of firefighting foam concentrate is still connected to the fire suppression systems in two other hangars, according to Executive Director Kristine Logan of Midcoast Regional Redevelopment Authority, the organization overseeing the second life of the former Brunswick Naval Air Station.

Scientists say even trace amounts of these manmade compounds used to make thousands of common household and industrial products can be harmful to people and can be linked to compromised immune and cardiovascular systems, decreased fertility, low birth weights, and several types of cancer.

PFOS is a well-studied forever chemical that 3M once manufactured in the United States for use in firefighting foam, paper and leather coatings, and aerosol mists. The company agreed to stop making PFOS in 2000, but it is still one of the most common forever chemicals in circulation.

It is unclear how many Maine fire departments, airports, fuel terminals and chemical plants still have PFOS-based firefighting foam concentrate in storage or in tanks awaiting use to deprive high-intensity fuel fires of the oxygen they need to burn. It is not illegal to use AFFF to fight fires in Maine.

The new tests show the concentrate from the spill last week mixed with 150,000 gallons of water to become foam that had a PFOS concentration of 7.5 million parts per trillion, filling the hangar 4 to 5 feet deep, emptying into sewer and storm drains, and spilling into a parking lot.

On Monday, the state said the hangar had been cleaned and all discharged foam from the hangar was removed, but it didn’t quantify how much had been recovered. The planes that had been inside the hangar during last week’s spill have already been cleaned once. A second and final cleaning is planned.

The hangar will be cleaned for a final time after the second wash of the planes is complete. Contracted crews will collect all of the rinse water for both plane and hangar cleanings, DEP said. The hangar offices will also be steam-cleaned by contracted response crews.

Large clumps of bubbles escaped the hangar through manhole covers where the expanding foam bubbled up through the drains. These clumps could be seen floating in the wind. A state toxicologist advised the public last week to stay away from the foam, which could become aerosolized.

Tests show PFOS concentrations in samples collected from a series of nearby foam-covered drainage ponds to be a little more than 1 million parts per trillion where the foam first entered and 701 parts per trillion where it would leave the ponds.

Kurt Pennell, a Brown University engineering professor with expertise in environmental toxicology, said the inlet result is very high and the outlet sample is way above the maximum contaminant level for drinking water, indicating the pond is highly contaminated.

FOLLOW THE WATER

“In terms of risk, the next step is figuring where that water is going, and if it has reached a public or private drinking water source,” said Pennell, who agreed to look at the state’s initial sample report to help interpret its findings for the public. “They are likely going to need to treat the ‘pond’ water.”

The AFFF was still foaming in the retention ponds on Monday, a week after the spill, the DEP said in statement. It is unclear how long the foam will be present. Weather and rain may increase the production of foam due to the agitation of the water, the agency said.

The state is working with partner agencies to determine best practices for foam mitigation.

The state will continue to sample the drainage ponds, the streams they feed, and Harpswell Cove, the part of Casco Bay where the drainage ponds eventually discharge. Monday’s spill may be the biggest, but it is far from the only forever chemical contamination that has occurred at Brunswick Landing.

The state is downplaying the spill’s risk to drinking water. The public water district is not at risk because it taps distant aquifers, the DEP said, and testing of leftover contamination at the former Brunswick Naval Air Station shows groundwater under Hangar 4 flows away from nearby residential wells.

PFOS is the most common of the 40 forever chemicals that Maine tests for to be found in the state’s freshwater fish. It is what Maine uses as a chemical marker to set consumption thresholds for fish, milk and beef, as well as forage grass for dairy cows.

The average American has just over 4 parts per billion of PFOS in their blood. Maine advises against consuming milk with 210 parts per trillion of PFOS, or beef with more than 3.4 parts per billion of PFOS. It advises limiting the consumption of fish with 3.5 part per billion of PFOS, and not eating a single fish that tops 60 parts per billion.