Consumer advocate Erin Brockovich and a New York-based law firm will investigate the drinking water contamination near former naval air bases outside Philadelphia, they said Tuesday.

In Bucks and Montgomery Counties, 16 public drinking wells and dozens of private wells have been shut off since 2014 after having been found contaminated with chemicals known as PFOA and PFOS.

Although officials say public water is now safe to drink, and private well owners are being moved onto the public supply, residents worry about the years they spent drinking the water - and many say the government and military have failed to give them all the answers they're seeking.

Residents contacted the law firm Weitz & Luxenberg "in large numbers," said Robin Greenwald, head of the firm's environmental and consumer protection unit. The firm, which has a Cherry Hill office, has done similar investigations in New York, Vermont, and New Hampshire and filed a class-action suit in February in a similar case in Hoosick Falls, N.Y.

"Nobody wants to drink a chemical," Greenwald said. "You have people who are really uncertain about what all this means."

Brockovich, who was portrayed by Julia Roberts in the eponymous 2000 film, has taken on environmental, pharmaceutical, and personal injury issues.

"It is time to give this community a voice and make sure those responsible are held accountable for this issue," Brockovich said in a statement.

The chemicals, known as perfluorinated compounds, have been linked to cancer and reproductive issues. They were used in firefighting foams at the air stations at Willow Grove and Warminster.

On Monday, U.S. Rep. Brendan Boyle (D., Pa.) called for a congressional hearing about the compounds. State officials last month said they would undertake a regional cancer study and would consider blood testing for residents.

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