[A] type of chemical called polyfluorinated compounds has been found in a private well at a farm near the Vermont Air National Guard base in South Burlington.
This class of chemical includes perfluorooctanoic acid, or PFOA, a carcinogen and toxicant with which Bennington manufacturer Chemfab was found to have poisoned hundreds of area wells.
This type of chemical is common in certain types of manufacturing, but it’s also found in firefighting foams, due to its exceptional resistance to thermal breakdown. The National Guard is a branch of the U.S. Air Force, which — like many agencies across the country that fight fires — began decades ago to use firefighting foam that contains PFCs.
The PFCs were found in a private well on a farm located about half a mile from the National Guard base, said Peter Walke, deputy secretary of the Agency of Natural Resources.
Walke said the affected well served the farm’s barn, and said the water it produced was primarily used to wash and to water livestock, although workers and the farm’s owner occasionally drank it.
Water in the contaminated farm well contains 110 parts per trillion of PFOA, and 23 parts per trillion of perfluorooctanesulfonic acid, a related chemical, Walke said.
The state of Vermont paid for the filter, but the National Guard is expected to compensate Vermonters for the expense, Walke said.
Vermont limits both chemicals combined to no more than 20 parts per trillion for drinking water within the state, Walke said, meaning that the state conducts investigations into groundwater found to contain more than that amount.
The base tested its own wells and soil in April, and positive results led officials to test nearby groundwater sources, said Sgt. Chelsea Clark, a public affairs specialist for the Vermont Air National Guard.
Water for the base itself, which is supplied by the Champlain Water District, has been found to be free of PFCs after multiple tests over years, said water district general manager Jim Fay.
The Champlain Water District takes its water from Lake Champlain, Fay said, and the district’s intake pipe is found beneath 75 feet of water, half a mile out into the lake.
Clark said it’s not been confirmed that the PFCs found in the well actually originated at the National Guard base. She said test results have also not been finalized, and said a final report on the contamination is expected in January.
The Vermont Air National Guard used firefighting foam that contained PFCs until 2014, Clark said.
Walke said he wasn’t surprised at the concentration of PFCs in nearby groundwater, given the frequency with which the Vermont Air National Guard used the foam.
“It’s a training center,” he said. “They’d light things on fire all the time, and put them out.”
Walke said National Guard officials have cooperated with state environmental regulators, and said that federal National Guard authorities understand that the agency has “an obligation to clean up” the pollution.
Clark did not say whether the National Guard will conduct “clean-up” of the polluted groundwater beyond the filter placed on the neighboring well.
Walke said that when polluters contaminate the environment or harm public health, “we as a state are going to hold you responsible to remediate that contamination.” Polluters usually do this voluntarily, Walke said.
Walke said that the state’s current relationship with the National Guard on that score is “not adversarial,” and said the Guard is cooperating “in a way that shows their commitment to righting the situation.”
PFCs are a class of chemicals that possess several unusual characteristics, among them a resistance to destruction by high heat. The fluorine-carbon chemical bond by which PFCs are held together are among the strongest known chemical bonds, and as a result these chemicals are extremely persistent when released into the environment.
This class of chemicals includes numerous toxicants, and the U.S. government continues to study their effects on human health, which aren’t well-known.
PFCs — and PFOA in particular — have been found in hundreds of drinking wells around the state.
Many of those polluted wells are believed to have been contaminated by chemicals deposited by smokestack emissions.
