Testing conducted by the Environmental Protection Agency revealed contamination in three private water wells located near an April blowout at a natural gas drilling site.

The EPA took water samples from seven private water wells near the Chesapeake Energy Corp. drilling site outside Canton in northeastern Pennsylvania's Bradford County, agency spokesman Roy Seneca said Friday.

Seneca declined to reveal the nature of the contamination, but said the agency has not drawn any conclusion about its cause. The EPA will sample the wells again in July.

Chesapeake has said a piece of equipment failed while its well in LeRoy Township was being hydraulically fractured, or fracked. In the fracking process, millions of gallons of water, along with chemical additives and sand, are injected at high pressure down the well bore to break up the shale and release the gas.

The accident spilled thousands of gallons of salty, chemical-laced flowback water into fields and a stream.

Chesapeake denied the spill had any effect on residential water supplies.

"The EPA water test results reflect the water quality that existed in these wells before any natural gas drilling activity began in this area," Chesapeake spokesman Brian Grove said in a statement Friday. "While EPA's latest results make a strong case for developing standards to govern water well construction, which currently is unregulated, they do not support any link between water quality and our natural gas operations."

Landowner Ira Haire, 71, whose well was tainted, said Friday he has "no problem at all with Chesapeake," adding the company has been in touch with him daily since the April spill. Chesapeake supplied the retired machinist with a temporary water tank, and it's installing a filtration system for his well. Haire declined to say what the EPA found in his well.

The state Department of Environmental Protection also has taken water samples from the water wells. The department is testing for a wide range of contaminants, including volatile organic compounds, strontium and barium, but a spokeswoman said Friday the results have not yet come in.