An Environmental Protection Agency employee said gas drilling damaged drinking-water aquifers in a Pennsylvania town, according to a presentation the staffer prepared for superiors before they agreed to end deliveries of clean water to the residents.
The previously unreleased document found that drilling known as hydraulic fracturing 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, Pennsylvania. The findings contradict those of Cabot Oil and Gas Corp., which drilled in the town and said the explosive methane gas was naturally occurring in domestic wells.
“Methane is released during the drilling and perhaps during the fracking process and other gas well work,” according to the undated power-point presentation prepared by the EPA coordinator in Dimock, who isn’t identified, for other agency officials. The report, obtained by Bloomberg from fracking critics, is based on a chemical analysis of methane in wells from 2008 through July 2012. The EPA said the findings in the presentation were 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.
The internal report, disclosed by the Los Angeles Times on July 27, doesn’t necessarily contradict the EPA’s conclusion released in July 2012 that the water in the Dimock homes was safe to drink. The EPA had already shown elevated levels of methane in some homes, but the agency doesn’t set a limit on methane levels in water, as the gas doesn’t impair the smell or taste of water. It can be explosive.
The report does show that at least one official determined that Cabot’s work damaged the water wells.
“You would really expect the federal government to follow up on this,” Kate Sinding, director of the Natural Resources Defense Council’s fracking defense project, said in an interview about this report. In Dimock and two other cases, the EPA abandoned its investigation “without a satisfactory explanation to the people in the communities,” she said.
The report doesn’t present evidence that the chemicals shot underground leaked into shallower wells, a possibility 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.”
EPA will consider this information as part of its ongoing study of fracking and drinking water, and residents were already aware that their water contained methane, she said.
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.
“Water quality issues that exist at isolated households in Dimock are believed to be associated with poorly constructed water wells that have, over time, allowed naturally occurring contaminants to leach into drinking water,” George Stark, a Cabot spokesman, said in an e-mail.
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 (under a year) but, in others cases the damage is long term (greater than 3 years),” the report says.