The Department of Environmental Conservation (DEC) announced Aug. 12 that Stewart Air National Guard Base in New Windsor has been classified by the state as a Superfund Site.
A preliminary investigation by the state in March revealed perfluorooctanesulfonic acid (PFOS) contamination in Washington Lake, Newburgh’s primary potable water source. Some of the highest concentrations of PFOS detected were found in an outfall from the Air National Guard Base that drains into Silver Stream, a primary tributary of Lake Washington, the DEC said.
It is holding the Department of Defense responsible for the contamination, and is requiring the department to produce “expedited” cleanup plans, as well as pay for the cleanup.
Superfund sites are sites where large amounts of hazardous waste may exist, and are separated into five classes, the first being the most polluted, and the fifth being the least polluted.
Stewart Air Base was labeled a Class 2, which the DEC defines as a “significant threat to the public health or environment.”
The DEC suspects the contamination came from Class B firefighting foam that was used on the base until 2002. PFOS was a major ingredient in the foam, the DEC said, and it does not break down.
According to a March 2016 advisory issued by the U.S. Environmental Protection Agency (EPA), exposure to PFOS “over certain levels may result in adverse health effects, developmental effects to fetuses during pregnancy or to breastfed infants (e.g., low birth weight, accelerated puberty, skeletal variations), cancer (e.g., testicular, kidney), liver effects (e.g., tissue damage), immune effects (e.g., antibody production and immunity), thyroid effects and other effects (e.g., cholesterol changes).”
PFOS is not regulated at the federal level, but it was added to New York State’s list of hazardous material in April, which is why the base qualifies as a Superfund Site, the DEC said.
Newburgh transitioned its water supply from Washington Lake to Brown’s Pond on May 2, and to the New York City Catskill Aqueduct on June 7 while a new carbon filtration system was built. The state estimates the new system will be complete by October 2017.
The City of Newburgh tested for PFOS from the end of 2013 to October of 2014 and found levels between 140 and 170 parts per trillion, which is below the EPA’s short-term health advisory of 200 parts per trillion.
In May, the DEC set the new lifetime drinking water health advisory level at 70 parts per trillion.
Groundwater samples collected from existing monitoring wells on the air base found concentrations of up to 3,160 parts per trillion, the DEC said, and surface water samples from the retention pond had concentrations of up to 790 parts per trillion. The highest concentrations of PFOS found so far were 5,900 parts per trillion.
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