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.

Pavillion Area Concerned Citizens provided this photo of the home of John and Katherine Fenton. It said the haze was from fracking fluids vaporized in the drilling process and that it lasted for about 10 minutes. Similar releases happened a dozen times over 3 days, it added.
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.
The process pumps pressurized water, sand and chemicals underground to open fissures and improve the flow of oil or gas.












