CHEYENNE — A group representing residents of a community where the U.S. Environmental Protection Agency has speculated that hydraulic fracturing may have contaminated their groundwater criticized Wyoming state officials for the first time, saying they're siding with the petroleum industry at the expense of those who have to live with polluted water.

For years state officials ignored the complaints of Pavillion-area residents and their suspicion that gas drilling had contaminated their groundwater, John Fenton, chairman of the group Pavillion Area Concerned Citizens, told The Associated Press on Tuesday.

"Now that we have credible scientific data, it seems like the state and industry — and they're not making any secret of it — they're just doing everything they can to discredit the study and the people doing the scientific work," Fenton said Tuesday.

Gov. Matt Mead toured the Pavillion area on Jan. 5, a trip hosted by Pavillion Area Concerned Citizens on Mead's precondition that the media not be told about it in advance.

Mead had no comment on Fenton's remarks to AP, spokesman Renny MacKay said. Encana Corp., which owns much of the polluted Pavillion gas field, has found much to fault with both the methodology and conclusions of the EPA study, and Mead himself in a Dec. 21 letter to EPA Administrator Lisa Jackson wrote that EPA employees had "rushed to conclusions that raise specters of cracked earth."

The conclusions aren't supported by available evidence, Mead wrote.

Petroleum companies use hydraulic fracturing, or fracking, to break open rock to aid the flow of oil and gas. The process involves large amounts of pressurized water and fine sand as well as relatively small levels of toxic chemicals.

The EPA agreed to begin investigating foul-smelling well water in Pavillion a few years ago at the request of local residents, who have described state officials' response to their pleas for help up to that point as discouraging.

The EPA found suspect chemicals in two wells it drilled to test groundwater in the Pavillion gas field. Agency scientists speculated that gas development, including fracking, may have been to blame for the contamination, according to a draft report on the study released Dec. 8.

The petroleum industry has long maintained there has never been a definitive case of groundwater pollution caused by fracking. The report marked the first time EPA theorized a link between fracking and groundwater pollution.

The governor raised other concerns and questions in last month's letter, including whether an upcoming peer review of the EPA study on the Pavillion contamination would "give deference to the unique geology and hydrology" in the Pavillion area.

On Tuesday, Mead released a follow-up letter to Jackson in which he said the EPA had yet to answer most of his questions.

"He continues to say that he has concerns about the scientific validity of the draft report. He would like assurances about the integrity of the EPA's methodology used in testing the two wells," MacKay said by email.

Mead also asked for a 30-day extension of the public comment period on the EPA report.

"EPA has stated from the outset that we are committed to public comment and peer review. We will continue to work with the state and others and will announce the next steps of the process soon," EPA Region 8 spokesman Rich Mylott said by email.

Pavillion Area Concerned Citizens said Tuesday it had asked EPA to stick by its plans for the public comment period, which began Dec. 14 and is scheduled to continue through Jan. 27. The group did so after Encana asked EPA to suspend taking public comments until it clarified which topics and issues should be the focus of comments on the Pavillion report.

The company also has asked EPA for more of the data that went into the report.

Encana officials are concerned that the EPA report strayed into hydraulic fracturing beyond its original scope of investigating foul-smelling and bad-tasting domestic well water, company spokesman Doug Hock said by email.

"The authors of this release seem intent on a predetermined conclusion. Our concerns with the EPA study are based on ensuring that a full and thorough scientific review of the data occurs rather than a predetermined conclusion," Hock said.