SOUTH BURLINGTON, Vt. — The Vermont Air National Guard says it’s found elevated levels of a toxic chemical in a private drinking water well near its base at the Burlington International Airport.

The Guard says test results this week show the levels of PFCs, or perfluorinated compounds, were above state guidelines.

The test came after the U.S. Air Force did a base-wide inspection for PFCs.

PFCs are used in firefighting foam and have been linked to cancer and other illnesses.

Public drinking water for the base and area is supplied by Champlain Water District.

The Guard says the district’s web site says its drinking water was tested in 2016 and found to be unaffected.

The Guard says it’s coordinating with state agencies in its response and installing a carbon filtration system to remove PFCs.