Traces of potentially harmful chemicals have shown up in three Colorado water systems, prompting officials to shut down three wells and start looking for the source.

Tests required by the U.S. Environmental Protection Agency detected compounds called PFOS and PFOA in utilities that serve about 69,000 people in Fountain and the unincorporated community of Security-Widefield.

The chemicals were once widely used in nonstick cookware coatings, firefighting foam, stain-resistant fabrics and other materials. The EPA says they've been linked to health problems in animals and could be bad for people, too.

No health problems have been linked to the compounds in Colorado.

The water utilities say they use multiple sources of water, and any chemicals would be highly diluted when they arrived at anyone's faucet.

More water tests are underway.