WEATHERFORD -- The Environmental Protection Agency had scientific evidence related to charges of water contamination against Fort Worth-based Range Resources, but changed course after Range threatened not to cooperate with a national study into hydraulic fracturing, according to a confidential report obtained by The Associated Press and interviews with Range officials.Range spokesman Matt Pitzarella told the Star-Telegram the report cited is incomplete and countered by other data made available to regulators. He also said that while Range declined to participate in the EPA study, "it is ludicrous" to conclude that Range, one of hundreds of U.S. gas producers, could stymie the EPA's efforts.EPA asked an independent scientist named Geoffrey Thyne to analyze water samples taken from 32 water wells near Range's Parker County wells. In the report obtained by the AP, Thyne concluded from chemical testing that the gas in the drinking water, including that from a well on the property of Steven Lipsky in the Silverado subdivision, could have originated from Range wells.Lipsky in 2010 had reported natural gas in his water.Thyne's report appears at odds with evidence introduced by Range at a hearing into the matter before the Texas Railroad Commission in 2011. At that hearing, which the EPA did not participate in, the agency's examiners found that the gas in Lipsky's well and other water wells in the area was "most likely" from a much shallower formation called the Strawn.Examiner Gene Montes said geochemical fingerprinting analysis of the gas in the contaminated wells indicated that it likely came from the Strawn, and didn't match Barnett Shale gas. The three-member Railroad Commission in March 2011 ruled Range was not at fault.Pitzarella said Thyne made his report in February 2011 and did not consider the Strawn as a source of the gas. He called Thyne "an outspoken critic of the gas industry" who has "awful science."At first, the EPA said the situation in Parker County was so serious that it issued a rare emergency order saying Lipsky and another homeowner were in immediate danger from a well saturated with flammable methane. It ordered Range to take immediate steps to trace the gas, but Range concluded its wells were not the source, leading to the Railroad Commission hearing.In March 2012, the EPA retracted its emergency order."I just can't believe that an agency that knows the truth about something like that, or has evidence like this, wouldn't use it," said Lipsky, who said he still lives wtih his family in the home but pays $1,000 a month to have water hauled in.The case isn't the first in which the EPA initially linked a hydraulic fracturing operation to water contamination and then softened its position after the industry protested.In Pavillion, Wyo., a similar dispute unfolded in late 2011, when the EPA said hydraulic fracturing could have contaminated groundwater. After industry and GOP leaders went on the attack, the agency said it had decided to do more testing. It has yet to announce a final conclusion.Hydraulic fracturing -- often called "fracking" -- allows drillers to tap into oil and gas reserves that were once considered out of reach because they were locked in deep layers of rock. It has contributed to a surge in natural gas drilling nationwide, but environmental activists and some scientists believe it can contaminate groundwater. The industry insists the practice is safe.The agency is conducting a national study into hydraulic fracturing. It issued a progress report in December on the study, which it expects to release in 2014.Range told EPA officials in Washington that so long as the agency pursued a "scientifically baseless" action against the company, it would not take part in the study and would not allow government scientists onto its drilling sites, said company attorney David Poole.Pitzarella said Poole's comments are accurate, but refer to its operations in Pennsylvania, where it is a major driller. Range sold its Barnett Shale properties in 2011 and the EPA is free to study whatever it wants there without Range's permission, he saidThe EPA refused to answer questions about its decision to withdraw its Parker County order against Range, instead issuing a statement by email that said resolving the matter allowed the agency to shift its "focus in this case away from litigation and toward a joint effort on the science and safety of energy extraction."Rob Jackson, chairman of global environmental change at Duke University's Nicholas School of the Environment, reviewed Thyne's report and the raw data upon which it was based. He agreed the gas in Lipsky's well could have originated in the Barnett Shale, the big natural gas field that underlies much of North Texas.Jackson said it was "premature" to withdraw the order and said the EPA "dropped the ball in dropping their investigation."Thyne's report relied on a type of testing known as isotopic analysis, which produces a unique chemical fingerprint that sometimes allows researchers to trace the origin of gas or oil.Jackson, who studies hydraulic fracturing and specializes in isotopic analysis, acknowledged that more data is needed to determine for certain where the gas came from. But even if the gas came from elsewhere, Range's wells could have contributed to the problem in Lipsky's water, because gas migrates, he added.Gas can migrate away from a producing well if it was improperly cased in steel and cemented in place. Range told the Railroad Commission hearing that tests showed its wells were not leaking, a position Pitzarella reiterated Wednesday. He said he has provided Jackson with additional data on the topic.Staff writer Jim Fuquay contributed to this report.