In this photograph taken April 15, 2009, an unidentified worker steps through the maze of hoses being used at a remote fracking site being run by Halliburton for natural-gas producer Williams in Rulison, Colo. The U.S. Environmental Protection Agency announced Thursday Dec. 8, 2011 in Wyoming, for the first time that fracking - a controversial method of improving the productivity of oil and gas wells - may be to blame for causing groundwater pollution. (AP Photo/David Zalubowski, File)

(AP) -- A U.S. Environmental Protection Agency draft finding that it may have detected groundwater pollution resulting from a controversial technique that plays a huge role in modern oil and gas development isn't settled science yet.

Nor is it settled politics, especially where hydraulic fracturing has been opening up vast new oil and gas reserves and creating economic opportunities that might not otherwise exist.

And so the debate over fracking is likely to continue.

Environmentalists have been sounding the alarm about fracking in Pennsylvania, New York State and other places with new gas drilling. They lauded Thursday's announcement concerning pollution in a central Wyoming community as a long time coming.

"In Wyoming, EPA is recognizing what experts - along with families in fracking communities across the country - have known for some time," Kate Sinding, an attorney with the Natural Resources Defense Council in New York City, said in an e-mail Thursday. "Fracking poses serious threats to safe drinking water."

Jan Jarrett, president of the environmental group PennFuture, said the news underscores the need for more research and protections in Pennsylvania.

"It really highlights the importance of getting the best possible safeguards in place," he said, adding that the report also shows that hydraulic fracking is not foolproof, as some in the industry have claimed.

The EPA emphasized that its announcement that it had found chemicals likely associated with gas production practices, including fracking, was just the first step in a review of its science. The draft report opens up a 45-day public comment period and a 30-day peer review process by independent scientists.

Even so, the oil and gas industry and its allies blasted the announcement as premature.

"Unsubstantiated statements coming from the EPA today stretch the data and cause unwarranted alarm and concern about a proven technology that allows our industry to safely extract oil and natural gas. The EPA's announcement is irresponsible and leads us to call into question its motives," said Bruce Hinchey, president of the Petroleum Association of Wyoming.

The practice called hydraulic fracturing is aimed at improving the productivity of oil and gas wells. It involves pumping pressurized water, sand and chemicals underground to open fissures and improve the flow of oil or gas to the surface.

Sen. James Inhofe called the study "not based on sound science but rather on political science."

"Its findings are premature, given that the Agency has not gone through the necessary peer-review process, and there are still serious outstanding questions regarding EPA's data and methodology," the Oklahoma Republican said.

Residents of Pavillion long have said their drinking water stinks of chemicals and is giving them health problems. Health officials last year recommended that they not drink their water and ventilate their bathrooms while showering.

Industry officials pointed out that the EPA announcement didn't focus on those domestic water wells but two wells drilled somewhat deeper into the aquifer specifically to test for pollution.

Moreover, the compounds could have had other origins not related to gas development, said Doug Hock, spokesman for Calgary, Alberta-based Encana, owner of the Pavillion gas field.

"Those could just have likely been brought about by contamination in their sampling process or construction of their well," Hock said.

An announced $45 million sale of the Pavillion field to Midland, Texas-based Legacy Reserves fell through last month amid what Encana said were Legacy's concerns about the EPA investigation.

The EPA, which has been studying the groundwater in Pavillion for more than two years, also emphasized that the preliminary findings are specific to the Pavillion area, not necessarily anywhere else in the U.S. The agency said the fracking that occurred in Pavillion differed from fracking methods used in regions with different geological characteristics.

The fracking occurred below the level of the drinking water aquifer and close to water wells, the EPA said. Elsewhere, drilling is more remote and fracking occurs much deeper than the level of groundwater that would normally be used.

"EPA's highest priority remains ensuring that Pavillion residents have access to safe drinking water," said Jim Martin, EPA regional administrator in Denver. "We look forward to having these findings in the draft report informed by a transparent and public review process."

The draft EPA report and the upcoming critiques of it come as states and the federal government continue to ponder whether and how to regulate fracking.

Last year, Wyoming became one of the first states to require oil and gas companies to publicly disclose the chemicals used in fracking. Colorado regulators are considering doing the same.

The public and industry representatives packed an 11-hour hearing on the issue in Denver on Monday. They all generally supported the proposal but the sticking point is whether trade secrets would have to be disclosed and how quickly the information would have to be turned over.

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