WEATHERFORD -- The Environmental Protection Agency had scientific evidence regarding 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.The EPA asked Geoffrey Thyne, an independent scientist, to analyze samples taken from 32 water wells near Range's Parker County wells in 2010. In the report obtained by the AP, Thyne concluded from chemical testing that gas in the water, including from a well on Steven Lipsky's property, could have originated from Range's wells.In December 2010, the EPA issued an emergency order directing Range to identify the source of the gas in the water wells and take other corrective actions. Range said its wells did not contaminate the water. Four months later, the Texas Railroad Commission agreed with the company, and the EPA withdrew its order in March 2011.Range spokesman Matt Pitzarella told the Star-Telegram that the confidential report obtained by the AP is incomplete and countered by other data made available to state and federal 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.At the 2011 hearing before the Railroad Commission, which regulates the oil and gas industry, the agency's examiners found that the gas in Lipsky's well and others was "most likely" from a much shallower formation called the Strawn.Pitzarella said Thyne made his report in February 2011, after the EPA issued its order, and did not consider the Strawn as a source. He called Thyne "an outspoken critic of the gas industry" who has "awful science."The EPA would not answer questions about its decision to withdraw its order against Range. Instead, it issued a statement by email that said resolving the matter let the agency shift its "focus in this case away from litigation and toward a joint effort on the science and safety of energy extraction."Lipsky, who still lives in his Parker County home and is involved in litigation with Range, told The Associated Press: "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." He said he pays $1,000 a month to have water hauled in.The agency is conducting a national study into hydraulic fracturing, which will include three sites in Wise County. The EPA expects to release it in 2014.Range told EPA officials in Washington that as 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, company attorney David Poole said.Pitzarella said Poole's comments 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 saidRob Jackson, chairman of global environmental change at Duke University's Nicholas School of the Environment, reviewed Thyne's report and the raw data it was based on.Jackson, who studies hydraulic fracturing and specializes in isotopic analysis, acknowledged that more information 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 said.Jackson said it was "premature" to withdraw the order and said the EPA "dropped the ball in dropping their investigation."Range told the Railroad Commission that tests showed its wells were not leaking, a position reiterated by Pitzarella. He said he has provided Jackson with additional data.Staff writer Jim Fuquay contributed to this report.