WASHINGTON — The Environmental Protection Agency on Thursday said it had found no evidence that the hydraulic fracturing process responsible for unlocking vast stores of oil and gas nationwide has caused “widespread systemic impacts on drinking water.”
But some water supplies have been contaminated and “there are potential vulnerabilities,” the agency warned, as it released a long-awaited, congressionally directed assessment of the technique used to stimulate oil and gas production at wells across the United States.
The five-year probe documented instances where waste water was spilled above ground and the integrity of wells themselves may have caused problems. But in releasing its draft assessment Thursday, the EPA said those instances were relatively infrequent.
“There are recognized instances where fracking-related activities related to releases that have impacted surface and ground water,” said the EPA’s top science adviser, Thomas Burke. “The number of documented impacts to drinking water resources is relatively small when compared to the number of fractured wells.”
Burke stressed “the study was not — nor was it intended to be — a numerical catalogue of all episodes of contamination.”
“This is a study of how we can best protect our water resources,” he told reporters on a conference call. “It’s not a question of safe or unsafe. It’s a question of understanding the vulnerabilities so we can . . . reduce those risks and protect our water resources.”
Industry leaders celebrated the report’s release as a vindication of hydraulic fracturing, which involves pumping sand, water and chemicals underground to open the pores of oil- and gas-bearing rock, allowing those hydrocarbons to flow out.
“The evidence gathered by EPA confirms what the agency has already acknowledged and what the oil and gas industry has known: Hydraulic fracturing is being done safely under the strong environmental stewardship of state regulators and industry best practices,” said Erik Milito, upstream group director for the American Petroleum Institute. “Hydraulic fracturing has been used safely in over a million wells, resulting in America’s rise as a global energy superpower, growth in energy investments, wages and new jobs.”
But environmentalists took a starkly different view, noting that EPA’s draft results show evidence of pollution in the past and highlight ongoing risks.
“The assessment smashes the myth that there can be oil and gas development without impacts to drinking water,” said John Noel, the national oil and gas campaigns coordinator for Clean Water Action. “Fracking is a complex process that poses a complex array of potential risks to drinking water.”
Critics said the EPA’s assessment is a long way from Obama administration officials’ testimony on Capitol Hill that fracturing is safe. This is a “watershed” moment for fracking because the EPA is formally confirming links to drinking water pollution, the group Earthworks said.
EPA’s Burke called the agency’s draft assessment “the most complete compilation of scientific data to date, including over 950 sources of information, published papers, numerous technical reports, information from stakeholders and peer-reviewed EPA scientific reports.”
But its scope has been criticized by hydraulic fracturing skeptics, who say the agency was forced to analyze data without forward-looking studies that include tests of wells both before and after hydraulic fracturing operations to determine baseline conditions and document changes.
In its draft, the EPA itself acknowledged that its findings could be affected by “insufficient pre- and post-fracturing data on the quality of drinking water resources.”
The review itself focused closely on the water cycle involved in hydraulic fracturing — from initially getting water supplies before those operations are underway to disposing wastewater after. It did not tackle other concerns tied to oil drilling or fracturing operations, including fears that disposing wastewater underground has ratcheted up seismic activity and earthquakes in some regions.
Fears about water contamination have coincided with the rise in hydraulic drilling. According to EPA estimates, roughly 9.4 million people lived within one mile of a hydraulically fractured well between 2000 and 2013. And nearly 7,000 sources of drinking water for public water systems serving more than 8 million people were located within one mile of at least one hydraulically fractured well during the same period.
Most of the public scrutiny has focused on the actual fracking process, when fluids are actively injected underground. If wells are poorly cemented, both the fluids pumped into them and oil and gas in the rock itself can move unexpectedly. And older wells may not have been built to withstand the stresses of hydraulic fracturing operations.
The EPA noted that there have been “several examples” where well failures “may have resulted in impacts to drinking water resources.” For instance, EPA noted that when an inner string of casing burst during fracturing operations in Killdeer, N.D., fluids were released on land and possibly entered an aquifer as well.
Oil industry leaders argue that most fracturing is done in geologic zones that are deep below drinking water resources, but the EPA noted that is not always the case, such as in the Antrim Shale in Michigan and the New Albany Shale that spans Illinois, Indiana and Kentucky. Sometimes oil and gas resources and drinking water supplies co-exist in the same formation.
There are other risks before and after fracturing operations.
Water consumption is one of them. Although the oil and gas industry is pursuing water-free techniques and recycling water, the EPA noted the process overall still involves a large amount of fluid, potentially millions of gallons per well.
And managing the waste water that flows out of wells is another challenge. There have been surface spills of that waste water; the EPA estimated that spills ranged from about 0.4 to 12.2 spills per 100 wells in Colorado and Pennsylvania.
Mark Brownstein, vice president of the climate and energy program at the Environmental Defense Fund, noted that “ongoing physical integrity of the wells and handling the millions of gallons of waste water coming back to the surface after fracking, over the lifetime of each well, are even bigger challenges” than the process of fracturing itself. “Relentless focus on these issues by regulators and industry is critical.”
Oil industry representatives have drawn a distinction between fracturing-related accidents — such as a surface spill of waste water — and incidents directly resulting from the process itself. But EPA’s Burke suggested those distinctions were irrelevant.
“It is important to protect our water resources that we take a broad look at hydrofracking activities,” Burke said. “The focus of our study was on wells that are fracked, but there is a narrow window of time in the life of a well, where that fracking activity actually takes perhaps three days or so. We looked far beyond that to look at the entire water cycle because we felt that’s the most important aspect of it.”
The study could bolster efforts by state and federal regulators to boost oversight of hydraulic fracturing, including a just-imposed, heavily criticized Interior Department rule that sets mandates for the activity on public land.
Separately, federal regulators at both the EPA and the Interior Department are planning new rules clamping down on methane emissions from oil and gas drilling operations, including wells that have been hydraulically fractured. And the Occupational Health and Safety Administration is advancing a rule that would limit the amount of silica to which workers are exposed.
The EPA’s draft assessment will be subject to public comment and a review from the agency’s science advisory board before it can be finalized.