CONCORD, N.H. — Several wells in a southern New Hampshire town have elevated levels of a toxic chemical linked to cancer.

The New Hampshire Department of Environmental Services says four wells it tested in Windham had levels of perfluorochemicals or PFCs ranging from 70.4 parts per trillion to 396 parts per trillion. The state standard is 70 parts per trillion.

PFCs were used at a company in the area, Central Metal Finishing, Inc.

Since last year, PFOAs have been found in the drinking water at 222 sites across the state. More than 180 sites are connected to contamination from Saint-Gobain Performance Plastics plant in Merrimack. Similar contamination was found near the company’s now-defunct plant in Vermont, and regulators in New York identified them as potentially responsible for chemical contamination in Hoosick Falls’ water.