Hydraulic fracturing activities have not led to widespread, systemic contamination of drinking water resources although potential water vulnerabilities exist, the US Environmental Protection Agency concluded in a draft assessment.
"Drinking water may be vulnerable to impacts," said Thomas A. Burke, EPA's science advisor and deputy assistant administrator of EPA's Office of Research and Development. "We feel very confident in our findings... the study was not, nor was it intended to be, a catalog of all instances of contamination."
The study was intended to help identify vulnerabilities so the nation can take measures to reduce risks and better protect its water, he said while briefing reporters on the assessment on June 4.
The American Petroleum Institute cited the safety and effectiveness of state and federal regulations along with current industry practices as contributing to the draft assessment's findings, which are being reviewed.
"After more than 5 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," said API Upstream Group Director Erik Milito. "Hydraulic fracturing is being done safely under the strong environmental stewardship of state regulators and industry best practices."
Mark Plummer, chief executive officer of Chestnut Exploration of Dallas, said the report serves as another affirmation to the public that fracturing is not a threat as some have suggested.
"This EPA conclusion reflects what we already knew--fracking is perfectly safe when done responsibly," Plummer said. "Hydraulic fracturing...has been given a bad name lately. While I am a firm believer that fracturing is safe when completed correctly, sometimes this kind of research is needed to put people at ease."
The report includes over 950 sources and follows water used for fracturing from water acquisition, chemical mixing at the well pad site, well injection of fracking fluids, the collection of fracturing wastewater and wastewater treatment and disposal.
Resources For the Future suggested the EPA report will help advance understanding of the vulnerabilities of drinking water resources to fracturing, but RFF noted that EPA's draft assessment lacked a systematic set of analyses that could narrow the range of uncertainty.
"The difference between understanding vulnerabilities and risk pathways and the scientific basis for decisions, while seemingly semantic, is large," RFF's Alan Krupnick and Katrina McLaughlin said. "The difference is a question of degree of uncertainty-do we have enough information to really advance the scientific basis, or are we still in the world of anecdotes? To the extent that data limitations force us to rely only on anecdotes, there is a way to go before decisionmaking can be improved."
Krupnick is co-director of RFF's Center for Energy and Climate Economics and a senior fellow. McLaughlin is a research assistant at RFF, based in Washington, DC.
EPA studied water cycle
Following a congressional request, EPA studied water used for fracturing starting with the acquisition of the water, chemical mixing at the well, injection of fracturing fluids, the collection of fracturing wastewater, and wastewater treatment and disposal.
"Once final, this assessment will give state regulators, tribes, and local communities and industry around the country with a critical resource to identify how best to protect public health and their drinking water resources," Burke said.
More than 20 peer-reviewed articles were published as part of the study. In addition, 9 peer-reviewed EPA scientific reports were released along with the draft assessment.
"More importantly, we reached out to the public...and industry," Burke said. "We conducted multiple meetings all over the United States." The draft assessment was submitted in what Burke called a continuing dialogue regarding fracturing and water.
The study looked at water resources currently being used as drinking water as well as other water resources that could potentially be used as drinking water in the future. The study is not a human health risk assessment, Burke said, adding that it also is not a list of wells.
EPA's review found specific instances where well integrity and wastewater management affected drinking water, but the agency noted the instances were small compared with "the large number of hydraulically fractured wells across the country."
Vulnerabilities to drinking water resources include:
• Water withdrawals in areas with low-water availability;
• Hydraulic fracturing conducted directly into formations containing drinking water resources;
EPA
• Inadequately cased or cemented wells resulting in below ground migration of gases and liquids;
• Inadequately treated wastewater discharged into drinking water resources;
• Spills of hydraulic fluids and fracturing wastewater, including flowback and produced water.
State vs. fed jurisdiction
States play a primary role in regulating most natural gas and oil development. EPA's authority is limited by statutory or regulatory exemptions under the Clean Water Act, Safe Drinking Water Act, the Comprehensive Environmental Response, Compensation and Liability Act, and the Resource Conservation and Recovery Act.
In instances where EPA's exemptions exist, states may have authority to regulate unconventional oil and gas activities under their own state laws.
The study will be finalized after review by the Science Advisory Board and public review and comment.
EPA conducted its study during 2009-13 while state agencies finalized an estimated 82 groundwater-related rules for oil and gas production, including hundreds of discrete rule changes, according to the Ground Water Protection Council.
"Continuous safety improvements have been an ongoing part of hydraulic fracturing for 65 years," said API's Milito. "That process will continue, with our support, under the oversight of state regulators who are most familiar with their own area's unique geology, hydrology, and other physical characteristics."
