In a stunning reversal, the U.S. Environmental Protection Agency (EPA) released a final report Tuesday that says hydraulic fracturing (fracking) can affect drinking water under some circumstances, and it identified several conditions where the effects could be more severe.
The report marks a significant departure from a draft assessment on the potential impacts from fracking on drinking water EPA issued in June 2015. At the time, the agency said it had found no systemic impacts to drinking water to date, but it conceded that there were "potential vulnerabilities," some of which were not unique to fracking.
"The value of high-quality science has never been more important in helping to guide decisions around our nation's fragile water resources," said Dr. Thomas A. Burke, EPA science advisor and deputy assistant administrator of EPA's Office of Research and Development. "EPA's assessment provides the scientific foundation for local decision makers, industry, and communities that are looking to protect public health and drinking water resources and make more informed decisions about fracking activities.
"This assessment is the most complete compilation to date of national scientific data on the relationship of drinking water resources and fracking."
According to EPA, the conditions where fracking could have more frequent or severe impacts on drinking water are:
Water withdrawals for fracking in times or areas of low water availability, particularly in areas with limited or declining groundwater resources;
Spills during the management of fracking fluids and chemicals or produced water that result in large volumes or high concentrations of chemicals reaching groundwater resources;
Injection of fracking fluids into wells with inadequate mechanical integrity, allowing gases or liquids to move to groundwater resources;
Injection of fracking fluids directly into groundwater resources;
Discharge of inadequately treated fracking wastewater to surface water resources; and
Disposal or storage of fracking wastewater in unlined pits, resulting in contamination of groundwater resources.
But EPA conceded that "data gaps and uncertainties" prevented it from being able to fully assess the potential effects on drinking water, both at the local and national levels.
"Because of these data gaps and uncertainties, it was not possible to fully characterize the severity of impacts, nor was it possible to calculate or estimate the national frequency of impacts on drinking water resources from activities in the fracking water cycle," EPA said.
EPA said 1 million wells have been fracked since the late 1940s, and that roughly one-third of them were fracked between 2000 and 2014. The agency estimated that 25,000-30,000 new wells were fracked in the United States every year between 2011 and 2014, but it said the decline in oil and gas prices led to a corresponding decline in the number of wells fracked. The total went down to about 20,000 in 2015, by the agency's estimate.
Between 2000 and 2013, the water sources for about 3,900 public water systems -- which collectively served more than 8.6 million people year-round in 2013 -- were located within one mile of at least one fracked well.
On the issue of water acquisition, EPA cited data from FracFocus, a publicly-accessible registry managed by the Groundwater Protection Council and the Interstate Oil and Gas Compact Commission. The agency found that the median volume of water used per fracked well varied widely -- from 76,818 gallons in California to 5.26 million gallons in Arkansas. Still, EPA acknowledged that fracking "uses a relatively small percentage of water when compared to total water use and availability at large geographic scales."
The stark difference in water usage created disparate impacts in the field, EPA found. As examples, the agency cited a 2011 incident where drinking water wells in an area overlying the Haynesville Shale ran out of water due to higher than normal groundwater withdrawals -- some of which were made for fracking operations -- and drought. EPA said groundwater impacts were also reported in Texas.
But EPA also found minimal impacts to drinking water in the Upper Colorado and Susquehanna River basins, and suggested that water management strategies help protect streams from depletion by water withdrawals for fracking operations.
On the issue of chemical spills, EPA found that 151 spills involving fracking fluids or additives occurred on or near well sites in 11 states between January 2006 and April 2012. The spills ranged from five to 19,320 gallons. Of the 151 spills, 13 were reported to have reached a surface body of water, usually creeks or streams, with spill volumes ranging from 28 to 7,350 gallons.
"Although impacts on surface water resources have been documented, site-specific studies that could be used to describe factors that affect the frequency or severity of impacts were not available," EPA said. "In the absence of such studies, we relied on fundamental scientific principles to identify factors that affect how hydraulic fracturing fluids and chemicals can move through the environment to drinking water resources.
"Because these factors influence whether spilled fluids reach groundwater and surface water resources, they affect the frequency and severity of impacts on drinking water resources from spills during the chemical mixing stage of the hydraulic fracturing water cycle."
EPA also said it found instances where three activities -- the injection of chemicals used in fracking, the handling of produced water from fracking operations, and the disposal of wastewater in aboveground tanks or pits, especially unlined ones -- led to impacts on drinking water sources.
The oil and gas industry blasted EPA over the final report.
"It is beyond absurd for the administration to reverse course on its way out the door," said Erik Milito, upstream director for the American Petroleum Institute. "The agency has walked away from nearly a thousand sources of information from published papers, technical reports and peer reviewed scientific reports demonstrating that industry practices, industry trends, and regulatory programs protect water resources at every step of the hydraulic fracturing process. Decisions like this amplify the public's frustrations with Washington.
"Fortunately, the science and data clearly demonstrate that fracking does not lead to widespread, systemic impacts to drinking water resources. Unfortunately, consumers have witnessed five years and millions of dollars expended only to see a conclusion based in science changed to a conclusion based in political ambiguity. We look forward to working with the new administration in order to instill fact-based science back into the public policy process."
Last week, President-elect Donald Trump selected Oklahoma Attorney General Scott Pruitt to lead EPA.
In a statement, the Texas Alliance of Energy Producers (TAEP) said EPA ignored the fact that thousands of wells have been fracked in the state and there have been no cases of groundwater contamination.
"The final EPA study has retreated from its previous draft conclusion of no widespread, systemic groundwater impact from fracking," TAEP said. "It now seems to bow to the pressure of the political extremists who are desperate to erase the success of fracking...EPA has wasted our taxpayer money on this political effort masquerading as a scientific study."
Merrill Matthews, resident scholar for the Institute for Policy Innovation, said that in EPA's newest report it had included the words "under some circumstances" when talking about drinking water effects but had removed references of there being no "widespread, systemic impact," which was in the June 2015 report.
"We've seen this situation again and again under [the Obama] administration," Matthews said. "Politics, not the evidence, determine this administration's findings...It's time for federal agencies to follow scientific evidence, not the pressure groups. And we expect [Pruitt] will do just that."