ARUNDEL, Maine (AP) A report from the Maine Center for Disease Control found PFAS chemical contamination in nearly half the public water supplies tested.

The agency had 19 water supplies tested because of their proximity to potential sources of PFAS contamination such as airports, landfills and paper mills. PFAS chemicals, which are sometimes described as “forever chemicals,” were found in nine of the water supplies.

Maine CDC provided its report on Tuesday to a PFAS task force organized by Democratic Gov. Janet Mills.

PFAS chemicals were found in towns including Arundel, Georgetown and Topsham. Maine CDC’s summary of the findings says a high percentage of water systems declined to take part.

Maine Public reports a Maine CDC spokesperson says the data is evidence for mandatory monitoring for the chemicals in community water systems.