WAKE FOREST — Wells in a second northern Wake County neighborhood have tested positive for a cancer-causing chemical, just two miles north of the Stony Hill community, where 21 wells were found tainted this past summer.

Investigators from county, state and federal regulatory agencies announced their finding at a news conference Thursday. A potential homebuyer had ordered tests on a well in the Mangum Estates subdivision west of Wake Forest. The test found trichloroethylene, a chemical used in manufacturing that’s known to cause cancer, liver problems and other illnesses.

That finding prompted further tests from the Environmental Protection Agency and the state’s Division of Waste Management. Out of 18 wells sampled in Mangum Estates, nine exceeded the EPA’s maximum level of TCE. Results of 50 more tests conducted within a half-mile radius are due back Friday, the EPA’s Ken Rhame said.

Rhame said the EPA doesn’t yet know whether the new site is related to the Stony Hill well issue. Division of Waste Management Director Jim Bateson confirmed reports that a contaminated groundwater plume appears to extend north from Stony Hill.

Two homes in Mangum Estates had water filtration systems installed Wednesday; seven others should have filters by the weekend, Rhame said. That will mean the water’s safe to drink again, but EPA hopes eventually to extend private water lines to the neighborhood.

A few miles south in the Stony Hill community, crews are building water lines from nearby neighborhoods served by Aqua North Carolina. They’ve connected nine homes along Stony Hill Road so far, and others will have water service by early next year. EPA and Wake County have tested more than 100 wells within a three-quarter-mile radius; they’re still waiting on some of the results.

The EPA has spent almost $1.5 million handling the contamination issue in Stony Hill. Officials said it could be designated a federal Superfund site in the future, which would allow more funding for cleanup. “Those programs are some time away,” said Joseph Threadcraft of Wake County Environmental Services.

Regulators think a former circuit board manufacturer on Stony Hill Road could be responsible for the contamination there. A neighbor has said he saw the business owner washing circuit board parts with a degreaser containing TCE more than 10 years ago.

Attorneys for state and federal agencies are pursuing the company, which has been known as C-Tron, Circuit Board Assemblies and Flextronics. It could be held responsible for the costs, though state regulators have been trying since the first tainted well was found in 2005. “I’m not ruling out” financial penalties, Rhame said.

Residents have criticized the state’s Division of Waste Management for failing to test more wells after the initial discovery in 2005. The agency put the affected home on a different water supply and stopped testing after seven nearby wells came up clear. Most newcomers to the area weren’t aware of the 2005 contamination.

Bateson responded to those concerns Thursday. He says the agency oversees thousands of contamination sites, and the Stony Hill site wasn’t high priority because investigators thought the issue was isolated. “We have to make decisions about how we deploy our resources,” he said.

Campbell: 919-829-4802