The U.S. Environmental Protection Agency was justified in ordering that drinking water be provided to several Parker County residents whose water wells were contaminated with methane and cancer-causing benzene in 2010, but additional work needs to be done to assess whether a risk still exists, according to an internal investigation released Tuesday.The report by the agency’s Office of Inspector General concludes a yearlong probe into a case that has been mired in politics and a persistent back-and-forth between Texas and the EPA over how to oversee oil and gas drilling operations. It also left residents in the affected area either using the same water wells or paying to truck in water from other sources.But the report’s findings could reopen a case that appeared to have been closed in 2012, when the EPA settled with Fort Worth-based Range Resources, the gas driller it suspected had contaminated the water, and withdrew its emergency actions. Range contended that its drilling did not cause the contamination and that the methane naturally migrated into the water.Now, the EPA is being asked to evaluate Range’s most recent tests for quality and determine whether there are still risks to public health or of explosions due to methane gas. The report also asked the EPA to work with the Texas Railroad Commission, the state agency that oversees oil and gas operations, to mitigate any problems.“Although EPA officials believe that current residents are not presently at risk, the overall risk faced by current and future area residents has not been determined,” the report says. “We believe that the EPA needs to implement cost-effective steps to better gauge the risk and document and disseminate its findings to affected residents.”The case began after Steve Lipsky, a resident of the Silverado subdivision in far south Parker County, noticed that his water bubbled like champagne. He alerted the Railroad Commission and eventually the EPA when he believed the state was not responding quickly enough.The EPA took its own tests, including isotopic fingerprinting designed to determine the origin of the gas and other chemicals, and decided that nearby drilling wells operated by Range Resources were the most logical culprit. The agency found that the gas in the water and the gas at Range’s drilling operation were nearly identical and that the levels of contamination in the residential wells were alarming.It filed an emergency order in December 2010, demanding that Range immediately supply two homes with safe drinking water, determine the origin of the contamination and mitigate the problem. The agency believed that methane gas and other chemicals leaked into the aquifer because of the company’s nearby hydraulic fracturing, used to extract natural gas and oil by pumping high-pressure, chemical-laced water to crack thick layers of rock.But the Railroad Commission conducted its own investigation, which disputed the EPA’s findings. The state agency insisted the aquifer had long been naturally contaminated with methane and that Range Resources was not to blame. The company accepted the state’s finding and disputed the EPA, setting the stage for a long, bitter and expensive legal fight.The two sides settled in March 2012, with Range Resources agreeing to test the wells for a year and share the findings with the EPA. But the company admitted no guilt and wasn’t ordered to provide residents with another water source.The settlement prompted Republican members of Congress from Texas to publicly accuse the EPA, and its Region 6 head, Al Armendariz, of going after Range Resources for no good reason and demanded an investigation. Armendariz came under fire and was forced to resign after a video surfaced showing him likening his approach at the EPA to Roman conquerors who used crucifixion to deter dissent.On Tuesday, Range spokesman Matt Pitzarella said the company was still reviewing the inspector general’s report. But he said the company agrees with the state’s finding that “Range’s activities did not cause or contribute to the long-standing matter of naturally occurring methane.”He did not immediately respond to questions about the company’s testing or the recommendation that the EPA determine the future risk to residents.To residents who live in the area, though, Tuesday’s report is only the beginning.“The truth has only started. This is only a piece of it,” Lipsky said, adding that he no longer uses the water from his well. Instead, he pays hundreds of dollars a month for an alternate source but said some of his neighbors still use the well water.“The holding tanks in people’s garages are going to explode and I don’t care where it’s coming from, someone is going to get killed,” Lipsky said. Lipsky and Range are engaged in ongoing litigation over the allegations. And other families who live near the Lipskys have complained about methane contamination in recent months.To Armendariz, a former professor at Southern Methodist University who now works for the Sierra Club, the inspector general’s report is “complete and total vindication of the work we did at EPA.”“Our evidence was solid and we followed the law, and all rules and regulations,” he said. This report includes material from the Star-Telegram archives.