CHEYENNE, Wyo. (AP) — Encana Corp. has gone on the offensive now that the U.S. Environmental Protection Agency for the first time has theorized a link between a petroleum industry practice called hydraulic fracturing and groundwater pollution in a Wyoming gas field.

The EPA suggested the link in a Dec. 8 draft report. On Tuesday, Encana outlined objections to the report in a conference call with reporters.

Encana spokesman Doug Hock says the objections have less to do with the data so much as the EPA's interpretation of its data.

Hydraulic fracturing, or "fracking," involves pumping pressurized water, sand and some chemicals underground to open fissures and improve the flow of oil or gas.

The EPA says fracking is the best explanation for chemicals found beneath the central Wyoming community of Pavillion.