- Screenshot
- Firefighting foam concentrate leaking into a hangar
Updated on June 25, 2024 with comments from Col. Jacob Roy.
A tank full of firefighting chemicals leaked onto the floor of a helicopter hangar at the Vermont National Guard base last week, and some of the toxic material likely reached the Winooski River, officials said on Monday.
The fire-suppression material began spreading across the hangar floor shortly before 9 p.m. on Thursday, according to surveillance video provided by the Guard. It shows a thick white substance flowing toward one of several Black Hawk helicopters operated by the Guard.
The liquid is a concentrate known as AFFF, or aqueous film-forming foam, which, when mixed with water, creates a foam that is better than plain water at suppressing fuel fires. But AFFF also contains PFAS chemicals. The group of water-resistant substances is now understood to be toxic and highly resistant to natural breakdown, earning the moniker "forever chemicals."
The Vermont Air National Guard has struggled to contain groundwater contamination from AFFF foam, which it has used for years to practice putting out aircraft fires. Neighboring property owners have complained their wells have been contaminated with PFAS.
The leak went undetected overnight until Friday morning, by which time some of it had reached a hangar floor drain — and flowed into South Burlington's sewer system.
Crews scrambled to prevent the chemicals from reaching a nearby wastewater treatment plant, but by Friday morning enough of the substance had reached it that a layer of foam up to three-feet thick covered the facility’s treatment ponds.
“I was not happy,” South Burlington Water Quality Superintendent Bob Fischer told Seven Days on Monday. “It looked like a bubble bath.”
The Guard hired contractors who sent a crew with a vacuum truck to suck up the foam from the plant, as well as from a pump station.
On Monday, Guard officials said they had captured about 650 of the 800 gallons of concentrate initially released. Fischer said it appeared teams prevented much of the foam from reaching the plant.
“They’ve recovered quite a bit of it, but there’s no way they could have gotten it all,” Fischer said. “I would assume some went into the river, and even though is a small amount, it's still a dangerous carcinogen.”
The plant is designed to clean sewage and, like most municipal wastewater plants, does not remove PFAS from wastewater, he said.
State lawmakers have tried to accelerate the phaseout of such toxic foams, but they have no power over the Guard, which takes its orders from the U.S. Department of Defense.
The spill did not appear to have disrupted the wastewater plant’s functions. The facility releases treated water into the Winooski River.
Contractors hired by the Guard will determine the extent of any river contamination, he said.
“We’re going to be testing for months,” he said.
A tank full of firefighting chemicals leaked onto the floor of a helicopter hangar at the Vermont National Guard base last week, and some of the toxic material likely reached the Winooski River, officials said on Monday.
The fire-suppression material began spreading across the hangar floor shortly before 9 p.m. on Thursday, according to surveillance video provided by the Guard. It shows a thick white substance flowing toward one of several Black Hawk helicopters operated by the Guard.
The liquid is a concentrate known as AFFF, or aqueous film-forming foam, which, when mixed with water, creates a foam that is better than plain water at suppressing fuel fires. But AFFF also contains PFAS chemicals. The group of water-resistant substances is now understood to be toxic and highly resistant to natural breakdown, earning the moniker "forever chemicals."
The Vermont Air National Guard has struggled to contain groundwater contamination from AFFF foam, which it has used for years to practice putting out aircraft fires. Neighboring property owners have complained their wells have been contaminated with PFAS.
Crews scrambled to prevent the chemicals from reaching a nearby wastewater treatment plant, but by Friday morning enough of the substance had reached it that a layer of foam up to three-feet thick covered the facility’s treatment ponds.
- Vermont Department of Environmental Conservation
- Foam covers the South Burlington Wastewater Treatment Plant tanks
The Guard hired contractors who sent a crew with a vacuum truck to suck up the foam from the plant, as well as from a pump station.
On Monday, Guard officials said they had captured about 650 of the 800 gallons of concentrate initially released. Fischer said it appeared teams prevented much of the foam from reaching the plant.
“They’ve recovered quite a bit of it, but there’s no way they could have gotten it all,” Fischer said. “I would assume some went into the river, and even though is a small amount, it's still a dangerous carcinogen.”
The plant is designed to clean sewage and, like most municipal wastewater plants, does not remove PFAS from wastewater, he said.
The tank that leaked had been decommissioned in 2014 because of environmental concerns, said Col. Jacob Roy. The tank was detached from the hangar’s sprinkler system, which now will release only water, Roy said. The 800 gallons of chemicals sat in the tank for a decade because the Guard considered the risk of release to be low, Roy said.
“It’s hard to understand why it was here for so long, but we’re just one piece of a national effort to work with this material and dispose of it properly,” he said. The investigation into what caused the release is ongoing, but it appears to have been a “mechanical failure,” Roy said.
“It’s hard to understand why it was here for so long, but we’re just one piece of a national effort to work with this material and dispose of it properly,” he said. The investigation into what caused the release is ongoing, but it appears to have been a “mechanical failure,” Roy said.
State lawmakers have tried to accelerate the phaseout of such toxic foams, but they have no power over the Guard, which takes its orders from the U.S. Department of Defense.
The spill did not appear to have disrupted the wastewater plant’s functions. The facility releases treated water into the Winooski River.
Contractors hired by the Guard will determine the extent of any river contamination, he said.
“We’re going to be testing for months,” he said.
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