Drilling for natural gas caused “significant damage” to drinking-water aquifers in a Pennsylvania town at the center of a fight over the safety of hydraulic fracturing, according to a report prepared by a federal official.
The previously unreleased document from an employee at the Environmental Protection Agency’s regional office found that drilling or fracking, in which water, sand and chemicals are shot underground to free trapped gas, caused methane to leak into domestic water wells in Dimock, Pa. The findings contradict Cabot Oil and Gas Corp., which drilled in the town and said the explosive methane gas was naturally occurring.
“Methane is released during the drilling and perhaps during the fracking process and other gas well work,” according to the undated slide show prepared by the EPA coordinator in Dimock, who is not identified, for other agency officials. The report, obtained by Bloomberg from critics of fracking, is based on a chemical analysis of methane in wells. The EPA said the findings in the presentation are preliminary and more study is needed.
Dimock, featured in the anti-fracking film “Gasland,” has become a symbol for opponents questioning the safety of fracking. In 2010, state regulators stepped in and said Cabot’s drilling contaminated local wells, a finding disputed by the company. A subsequent EPA investigation said the water posed no health risks to town residents.
“You would really expect the federal government to follow up on this,” Kate Sindig, director of the Natural Resources Defense Council’s fracking defense project, said in an interview about the report. In Dimock and two other cases, the EPA abandoned its investigation “without a satisfactory explanation to the people in the communities,” she said.
Although the internal report, disclosed by the Los Angeles Times on July 27, does not necessarily contradict the EPA’s 2012 finding of elevated levels of methane and conclusion that the water was safe to drink, it does show that at least one official determined that Cabot’s work damaged the water wells. The report does not present evidence that the chemicals shot underground leaked into shallower wells, a possibility that scientists and industry representatives say is much less likely.
The report “is a preliminary evaluation that requires additional assessment in order to ascertain its quality and validity,” Alisha Johnson, an EPA spokeswoman, said in an e-mail. “The data and conclusions have not been peer-reviewed and do not in any way reflect an official agency position.”
The EPA will consider this information as part of its ongoing study of the impact of fracking on drinking water, she said.
The U.S. government does not set a limit on methane levels in water, as the agency says methane does not impair the smell or taste of water. The gas can, however, be explosive.
Last month, researchers from Duke University released a similar analysis of the methane isotopes. They determined that gas found in many water wells has the characteristics of the Marcellus Shale, from deep undergound, and that distance from gas wells was the most significant reason for high concentration of gas in the water.
Scientists affiliated with Cabot released research in May that found no connection between drilling and methane levels. George Stark, a company spokesman, didn’t return telephone and e-mail messages Monday.
“EPA’s review of data before and after its investigation suggested no need for additional action,” Steve Everley, a spokesman for the industry group Energy in Depth, said in an e-mail. “That wasn’t a conspiracy to conceal differing opinions, it was a reflection of reality.”
Gas production in Pennsylvania surged in the past few years as companies expanded their use of fracking. The Marcellus Shale is about 5,000 feet under Pennsylvania, separated by thick rock layers from water aquifers, which are at most a few hundred feet beneath the surface.
The surge in fracking has been accompanied by complaints from many homeowners who say their water has been contaminated, resulting in sick children, dead livestock and flammable tap water. Industry groups representing companies say evidence has failed to establish that water contamination is tied to fracking.
The internal EPA report concludes that the causes of gas migration could be drilling, spills or fracking. “In some cases the aquifers recover [in less than a year] but, in others cases the damage is long term [longer than three years],” the report says.