EPA report leaves questions on fracking's risks to water

Hydraulic fracturing, which has transformed the United States into an international leader in oil and gas production but stirred deep concerns about its risks to the environment, has not caused significant damage to drinking water - but it does pose risks, the Environmental Protection Agency concluded Thursday in its most comprehensive review of the drilling method.

The EPA, in a draft report based on a detailed, four-year review, said that although so-called fracking operations "have not led to widespread, systemic impacts on drinking water resources, there are potential vulnerabilities in the water life cycle that could impact drinking water."

The study did find evidence of problems associated with the procedure, which involves injecting liquids at high pressure into underground formations to extract oil and gas.

It found specific instances in which well integrity and wastewater management related to fracking activities had affected drinking-water resources, but it said these instances "were small compared to the large number of hydraulically fractured wells across the country."

How comprehensive the report is remains in question. The agency alluded to its well-documented problems in gathering information, including instances of lack of cooperation from the oil and gas industry.

The EPA said the small number of cases it had identified in which fracking had an effect on drinking water could be partly explained by that lack of information.

"This finding could reflect a rarity of effects on drinking water resources, but may also be due to other limiting factors," the report said. "These factors include: insufficient pre- and post-fracturing data on the quality of drinking water resources; the paucity of long-term systematic studies; the presence of other sources of contamination precluding a definitive link between hydraulic fracturing activities and an effect; and the inaccessibility of some information on hydraulic fracturing."

In less than a decade, fracking has remade the United States into a powerful player in global oil markets, easing concerns about the nation's long-term energy supply even as it has raised new concerns about fracking's potential to cause earthquakes, threaten underground water resources, and contribute to the carbon emissions that cause climate change.

The report is one of the first major environmental analyses of fracking conducted at the federal level, and it brought swift reaction from different sides of the debate.

"After more than five years and millions of dollars, the evidence gathered by EPA confirms what the agency has already acknowledged and what the oil and gas industry has known," Erik Milito, director of the American Petroleum Institute's Upstream Group, said in a statement on the institute's website.

Mark Brownstein, vice president for the climate and energy program at the Environmental Defense Fund, said that EPA officials themselves had conceded they might not have sufficient information. He said risks could increase as fracking continues.

"The process of fracking itself is one risk factor," Brownstein said. "But in fact it's not the biggest one. Ongoing physical integrity of the wells and handling the millions of gallons of wastewater coming back to the surface after fracking, over the lifetime of each well, are even bigger challenges. Relentless focus on these issues by regulators and industry is critical."