A controversial method of drilling for oil and natural gas appears to be the cause of groundwater pollution in a central Wyoming town, the U.S. Environmental Protection Agency said Thursday in its first statement implicating what proponents see as the next great energy boom.

The EPA last month said it had found compounds associated with chemicals used in the drilling process known as hydraulic fracturing, or fracking, in the groundwater beneath Pavillion. Many residents say their well water has reeked of chemicals since the drilling began there and first complained to the EPA in 2008.

But until Thursday, the EPA said it could not speculate on where the contaminants came from.

In the draft report (.pdf) released Thursday, the EPA said that "the explanation best fitting the data ... is that constituents associated with hydraulic fracturing have been released into the Wind River drinking water aquifer."

Health officials had earlier advised residents not to drink their water after the EPA said it had found benzene and other hydrocarbons in wells it tested.

http://usnews.msnbc.msn.com/_news/2011/12/08/9302971-energy-fracking-boom-tainted-by-epa-finding-contaminants-in-drinking-water