EPA's Study of Hydraulic Fracturing and Its Potential Impact on Drinking Water Resources

Questions and Answers about EPA's Hydraulic Fracturing Study

General Study Background
Hydraulic Fracturing Study Draft Assessment Report
Peer Review and Quality Assurance Process
Hydraulic Fracturing Study Progress Report (Released 2012)
Stakeholder Outreach and Engagement 
Case Studies
Analysis of Existing Data
Environmental Justice

General Study Background

Q: Why is EPA doing this study?

A: Responsible development of America’s unconventional oil and natural gas resources offers important economic, energy security and environmental benefits. EPA is committed to studying and addressing potential concerns related to unconventional oil and natural gas development so that the public has confidence that it will proceed in a safe and responsible manner. In its FY2010 Appropriations Committee Conference Report, Congress urged EPA to study the relationship between hydraulic fracturing and drinking water, using the best available science, independent sources of information, and to conduct the study in consultation with others using a transparent, peer-reviewed process. EPA announced in March 2010 that it would conduct a research study to investigate the potential impacts of hydraulic fracturing on drinking water resources.

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Q: Will the study look at potential effects on resources other than drinking water (air, ecosystems, fish, occupational risks, etc.)?

A: No, the current study focuses on potential impacts to drinking water resources. However, the study plan identifies important areas that merit further research, including potential impacts on air, ecosystems, occupational risks and other topics.

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Q: How frequently will EPA update the public on the progress of the research?

A: EPA is committed to updating the public as we make progress. EPA released a Progress Report on the study in December 2012. Updates on the study will be provided regularly in a variety of formats, including website updates, briefings via webinar, etc. New EPA peer reviewed papers reflecting research that was conducted in support of the study have been posted online and are available here.

EPA’s stakeholder roadmap outlines the plan to build upon the Agency’s commitment to transparency and stakeholder engagement during the development of the Hydraulic Fracturing Study Plan, and will help inform the draft assessment report. To learn more about how you can get involved please visit: http://www2.epa.gov/hfstudy/how-get-involved-epas-study-hydraulic-fracturing.

You can also sign-up to receive EPA’s hydraulic fracturing research email alerts.

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Q: How are drinking water resources defined in this study?

A: For this study, drinking water resources include any body of ground or surface water that could now or in the future be a source of public or private drinking water.

“Ground water” includes water found underground—usually in aquifers, which supply wells and springs. “Surface water” includes all water naturally open to the atmosphere, such as rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, and so on.

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Q: Will the study evaluate the potential impacts of underground waste injection?

A: No, the evaluation of the potential impacts of storing hydraulic fracturing wastewaters and flowback in underground injection wells is outside the scope of the study plan. (See chapter 13 of the study plan for a further discussion of this topic).

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Q: In November 2012, EPA published a Federal Register Notice, establishing a docket where stakeholders could submit relevant data and scientific literature to ensure that EPA is up-to-date on evolving industry practices and technologies. Is the submitted information available online?

A: Yes, the information submitted to the docket is available here.

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Q: How has the research program changed since the publication of the Study Plan?

AThe EPA has modified some of the research projects since the publication of the Study Plan, including:

  •  FracFocus Analysis: In 2011, a voluntary industry database for chemicals used in hydraulic fracturing, called FracFocus, was made available online. The data are being analyzed to identify the chemicals used in hydraulic fracturing fluids as well as the geographic distribution of water and chemical use.
  • Prospective Case Studies: Due to scheduling conflicts, the location of a previously identified prospective case study is no longer being considered. The EPA continues to work with industry partners to identify locations and develop research activities for prospective case studies.
  • Chemical Prioritization: As part of the toxicity assessment, EPA planned to prioritize a subset of chemicals used in hydraulic fracturing for future toxicity screening. However, based on the recommendations of the Science Advisory Board, the Agency will not conduct screening assays on a subset of chemicals, but will continue efforts to identify and evaluate existing toxicity data.
  • Reactions Between Hydraulic Fracturing Fluids and Shale: EPA decided to discontinue its work on the interactions between hydraulic fracturing fluids and various rock formations, as the research is being conducted by the US Department of Energy.

For more details on changes to the research program, please see chapter 2 of the Progress Report.

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Q: How is the final study plan different from the draft study plan?

A: The core research questions and general study approach are the same in the final study plan as they were in the draft document. In the final study plan, we included more details about the research activities to improve the public’s understanding of how we are carrying out the study.

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Q: Did EPA expand the scope of the study?

A: No, EPA has not expanded the scope of the hydraulic fracturing study. The core research questions and general study approach are the same as they were in the draft document.

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Q: What topics fall outside of this study’s scope?

A: EPA recognizes that the public has raised concerns about hydraulic fracturing that extend beyond the potential impacts on drinking water resources. Areas that fall outside of this study’s scope include, for instance: air impacts, ecological effects, seismic risks, specific health impacts, public safety, and occupational risks. For more information, see chapter 13 of the Final Study Plan.

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Hydraulic Fracturing Study Draft Assessment Report

Q: What is the status of the study?

A: Work is underway to release a draft assessment report for public comment and peer review. EPA is considering the results of original research projects, existing scientific literature, and information submitted by stakeholders.

The study's individual research projects are being published as peer reviewed journal articles, or as EPA reports that undergo peer review by external technical experts. The published papers are available here and future papers will be posted as they become available.

For detailed information on the study's research projects and approaches, please see the Progress Report that was released in December 2012.

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Q: What is the purpose of the draft assessment report and how will it be used?

A: The draft assessment report will represent the state-of-the-science on hydraulic fracturing and its potential impact on drinking water. This assessment will be based upon the results of extensive review of the literature, EPA peer review research projects, and input from industry, states and other stakeholders. The overall purpose of the report is to:

  • Contribute to the understanding of potential impacts of hydraulic fracturing on drinking water resources.
  • Inform and promote dialogue among federal, tribal, state, and local government entities, industry, non-governmental organizations, and other stakeholders.
  • Identify knowledge gaps and information needs.

The results of the study will inform the public and provide decision-makers at all levels with high-quality scientific knowledge so they can make decisions that are protective of people's health and environment.

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Q: What types of potential impacts will be addressed in the draft assessment report?

A: The report will address impacts related to:

  • Normal hydraulic fracturing operations reflecting modern typical practices.
  • Potential and actual accidents or unintended events associated with hydraulic fracturing activities.
  • Potential immediate, short-term, and long-term impacts of hydraulic fracturing activities.

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Q: Will EPA determine specific health effects of any impacts to drinking water?

A: The study will summarize existing data regarding the toxicity and potential human health effects associated with hydraulic fracturing-related chemicals. While the study may point to chemicals associated with hydraulic fracturing that could be toxic to human health, we will not be able to specify the health effects at different levels of exposure to a certain chemical, nor specify what the added health risk to the community might be. Results of the study could be used to support future research.

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Q: Will this study either assess existing regulations or recommend any new regulations?

A: No. This study is being conducted by EPA’s Office of Research and Development, the scientific research arm of EPA, and thus will neither assess current nor recommend any new regulations.

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Q: What sources of information will support the draft assessment report?

A: Sources of information will include:

  • Existing scientific literature, government reports, technical papers, with an emphasis on peer reviewed literature.
  • Results from the agency's ongoing original research projects.
  • Information submitted by stakeholders through technical workshops and roundtables, the EPA docket, and Science Advisory Board meetings.

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Q: How did the 2013 technical workshops inform the draft assessment report?

A: In 2013, five technical workshops were held to provide EPA timely and constructive feedback on data and analysis developed in the study, and to assure that EPA is current on changes in industry practices and technologies. Workshop topics included Analytical Chemical Methods, Well Construction and Operation, Subsurface Modeling, Water Acquisition Modeling, and Case Studies. For details on how each workshop informed the draft assessment report, please click here.

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Q: What is the geographic scope of the draft assessment report?

A: The scope will be of national scale. The report will evaluate available information for multiple regions, and potential impacts are expected to be evaluated at multiple scales, including: single wells, watersheds, and shale plays.

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Q: Given the rapidly changing hydraulic fracturing practices, will the results of EPA’s study be relevant in the future?

A: To ensure that EPA is up-to-date on evolving hydraulic fracturing practices and technologies, the Agency requested relevant data and scientific literature to inform the study through a Federal Register Notice. EPA is soliciting relevant information from experts and the public through ongoing stakeholder engagement activities. The agency is also conducting a comprehensive literature review to inform the research.

The results of EPA’s research will contribute to the state of knowledge on the relationship between hydraulic fracturing and drinking water resources. While the Agency acknowledges that some companies may adopt new technologies and practices in the future, others may continue to use current or older technologies and practices.

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Q: Will the public have an opportunity to comment on the draft assessment report?

A: EPA plans to release the draft assessment for peer review and public comment. As a HISA, the study will undergo a rigorous and transparent peer review by EPA's SAB to ensure all information is high quality. EPA plans to host public webinars following the release of the draft assessment and before the peer review process to allow the public and stakeholders an opportunity to ask questions about the report. This will ensure EPA can explain its report and findings clearly and allow for a more effective peer review and public commenting process.

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Peer Review and Quality Assurance Process

Q: How will EPA ensure that the study design and the results are not biased in any way?

A: The study itself is being conducted according to the SAB reviewed study plan and is adhering to a rigorous application of the agency’s quality assurance principles. This approach will ensure that results generated are scientifically sound.

Furthermore, EPA has engaged multiple stakeholder groups in the planning process in an effort to ensure that the study is conducted in an unbiased and objective manner. These stakeholder groups include the public, industry, non-governmental organizations, federal, state, interstate, and tribal agencies.

The results of the study will be synthesized in a draft assessment report that will undergo a quality assurance review and a thorough peer review with a public comment process.

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Q: What is a quality assurance project plan (QAPP)?

A: A quality assurance project plan (QAPP) describes procedures that ensure that only valid data are generated and used in our study. QAPPs are internal scientifically deliberative documents that describe the methods and quality assurance protocols used in our study. It is an internal planning document prepared, reviewed, and approved by agency technical and quality assurance experts. The QAPP may be updated throughout a project to document changes needed to the initial approach based on results obtained or observations made during the study.

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Q: Are quality assurance project plans available for all parts of the study? 

A: Quality assurance project plans are developed for all parts of the study for which research has been initiated. They are dynamic documents. Based on early outcomes in individual research projects, we may need to modify our initial plans before moving on to next steps. In all instances, any such modifications will be within the bounds of the study plan, both substantially and geographically, and will be subject to the same review and approval process as the initial quality assurance project plan.

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Q: What is EPA's review process for QAPPs?

A: Quality assurance project plans (QAPPs) for the hydraulic fracturing study are reviewed and approved by quality assurance managers, senior technical research leads and the study coordinator among others. These reviews help ensure the data generated will meet the research goals as stated in the study plan. QAPPs must be approved before work can begin. Any modified QAPP must be subjected to the same review and approval process as the initial plan.

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Q: Will EPA provide its QAPPs for the hydraulic fracturing study to the public? 

A: Yes, the quality assurance project plans are available to view and print on our "Quality Assurance Project Plans for the Hydraulic Fracturing Study Plan" page.

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Q: How will EPA ensure unbiased results from the existing data analysis?

A: Analysis of existing data includes data from peer-reviewed literature, state and federal agencies, industry responses to information requests, and data obtained from various publically available databases. We will consider data that is submitted to us from a variety of sources, but will always give priority to that literature which is peer-reviewed. EPA rigorously adheres to Quality Assurance Guidelines, which qualify the source and reliability of the information analyzed.

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Q: Did EPA incorporate all of the Science Advisory Board’s (SAB) suggestions? If not, why not?

A: EPA appreciates the great effort made by the SAB to help improve EPA's hydraulic fracturing study plan.  EPA incorporated most of the SAB’s suggestions. We did not incorporate suggestions that concerned issues that are not uniquely relevant to the potential impact of hydraulic fracturing on drinking water resources, are under the purview of other government entities, or require work that exceeded the scope of the study.  You can view a table detailing EPA’s response to the SAB (PDF) . The table indicates where EPA incorporated individual suggestions, and where EPA did not, gives an explanation of why the suggestion was not incorporated.

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Q: Have scientists published peer reviewed papers on original research projects?

A: Yes. The study's individual research projects are being published as peer reviewed journal articles, or as EPA reports that undergo peer review by external technical experts. The published papers are available here and future papers will be posted as they become available.

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Hydraulic Fracturing Study Progress Report (Released 2012)

Q: What does EPA plan to do with the information contained in the Progress Report?

A: EPA released the progress report to provide the public with the latest information on the work being undertaken as part of the Hydraulic Fracturing Research Study. The report outlines work that has been underway and cannot be used to draw conclusions about the potential impacts of hydraulic fracturing on drinking water resources. A draft assessment report will provide a synthesis of the data collected and will help inform Agency decision-making.

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Q: Why can’t this report be used to draw early conclusions about the potential impact of hydraulic fracturing on drinking water resources?

A: In order to answer EPA's study questions, we need to synthesize the results from all of the research projects undertaken as part of the study, which includes a thorough review of existing literature. The progress report explains what EPA has done as of December 2012, but does not provide the information or the synthesis necessary to draw conclusions or to answer the study questions.

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Q: Did the Progress Report undergo peer review?

A: As a Highly Influential Scientific Assessment, the draft assessment report will receive meaningful and timely peer review in accordance with EPA’s peer review handbook. In March 2013, the EPA's Scientific Advisory Board (SAB) formed an ad hoc panel of independent experts who provide periodic advice and review of EPA's hydraulic fracturing research, starting with a consultation to provide feedback on its 2012 Progress Report and concluding with a peer review of the draft assessment report. After the establishment of the SAB ad hoc panel, the SAB held a meeting in May 2013 to review the Progress Report and offer the public an opportunity to provide oral and written comment for consideration. In addition, a public teleconference by the SAB was held in November 2013 to allow for additional opportunity for the public to provide oral and written comment. The EPA plans to consider individual experts’ comments, which will be informed by public comment, in the development of the draft assessment report that will undergo a formal SAB peer review. For more information on the SAB process, please visit: http://yosemite.epa.gov/sab/sabpeople.nsf/WebCommittees/BOARD

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Stakeholder Outreach and Engagement 

Q: How is EPA working with stakeholders, including industry, non-governmental organizations, and other state and federal agencies, to conduct the study?

A: Stakeholder input has played, and will continue to play, an important role in the hydraulic fracturing study. EPA has engaged stakeholders through:

  • technical workshops,
  • technical roundtables,
  • public webinars and informational meetings,
  • federal, state, and tribal partner consultations,
  • sector-specific meetings,
  • opportunities to submit electronic or written comments

For more detail on how EPA has been working with stakeholders, please see our "How You Can Get Involved" page.

In addition, EPA has worked with stakeholders to gather and understand specific sources of data for the following research projects:

  • Review of State and Industry Spill Data: EPA is reviewing data sources obtained from agencies in the following nine states: Arkansas, Colorado, Louisiana, New Mexico, Oklahoma, Pennsylvania, Texas, Utah, and Wyoming.
  • Retrospective Case Studies: EPA is working closely with state agencies to conduct the research.
  • Wastewater Treatment Studies: EPA is working with state agencies and wastewater treatment facilities in Pennsylvania to obtain samples of raw and treated hydraulic fracturing wastewater.
  • Well File Review: EPA is reviewing and analyzing information about hydraulically fractured oil and gas production wells that were provided by nine well operating companies. EPA is also meeting with the companies to ensure that we have an accurate understanding of the information they provided. 
  • FracFocus: The Ground Water Protection Council provided EPA with information reported by oil and gas operators to FracFocus, a publicly accessible hydraulic fracturing chemical registry developed by the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission.

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Q: How is EPA working with other federal agencies?

A: EPA has exchanged information with the Department of Energy and the Department of the Interior/US Geological Survey on research and findings relevant to our study. In addition, as part of the study’s research project on Subsurface Migration Modeling, EPA has contracted with the Department of Energy’s Lawrence Berkeley National Laboratory to conduct research on the potential for hydraulic fracturing fluids to move from the fractured zone to drinking water aquifers. For more information, please see chapter 4 of the Progress Report.

More broadly, the Federal Multiagency Collaboration on Unconventional Oil and Gas Research, comprised of the US Department of Energy, the US Department of the Interior, and the US Environmental Protection Agency, is working together through a Memorandum of Understanding (MOU) to identify the highest priority research associated with safely and prudently developing important unconventional oil and gas domestic onshore resources. For more information, please review the Federal Multiagency Collaboration on Unconventional Oil and Gas Research Strategy.

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Case Studies

Q: Where is EPA conducting case studies? 

A: EPA has selected case studies that the Agency believes will provide the most useful information about the potential impacts of hydraulic fracturing on drinking water resources under a variety of circumstances.

EPA selected five retrospective case studies located in:

• Bakken Shale - Killdeer, Dunn County, North Dakota 
• Barnett Shale - Wise County, Texas 
• Marcellus Shale - Bradford and Susquehanna Counties, Pennsylvania 
• Marcellus Shale - Washington County, Pennsylvania 
• Raton Basin – Las Animas and Huerfano Counties, Colorado 

EPA currently is working closely with industry partners to identify locations for prospective case studies. 

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Q: How were the retrospective case study sites chosen?

A: The EPA identified, prioritized and selected the case studies based on a rigorous set of criteria and site visits by EPA scientists who will be conducting the research. Decision criteria included proximity of population and drinking water supplies, evidence of impaired water quality, health and environmental concerns and knowledge gaps that could be filled by the case study. Scientists prioritized sites based on geographic and geologic diversity, population at risk, site status (planned, active or completed), unique geological or hydrological features, characteristics of water resources, and land use. 

Background: EPA invited stakeholders nationwide to nominate potential case studies through informational public meetings and the submission of electronic or written comments. Of the 48 case studies nominated, EPA selected five for inclusion in the study. Learn more about the case study locations and the criteria for selecting those locations.

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Q: What is a retrospective case study, and how does it contribute to the greater study?

A: Retrospective case studies occur at sites where hydraulic fracturing has already occurred, and where contamination of drinking water resources has been reported.

Goals: Researchers will first determine whether contamination has occurred. If it has, they will then work to identify the probable cause of contamination.

Contribution: Retrospective case studies may provide information about which, if any, specific geologic and hydraulic fracturing conditions could contribute to impacts on drinking water resources by hydraulic fracturing activities. This is important because the conditions under which hydraulic fracturing occurs at one site may vary widely from the conditions at another site, so that the potential for impacts on drinking water resources could also be different.

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Q: What is a prospective case study, and how does it contribute to the greater study?

A: In prospective case studies, research at the site begins before hydraulic fracturing occurs, and then continues during and after hydraulic fracturing activities.

Goals: Scientists will determine whether, during the limited period of the study, hydraulic fracturing activities led to any impacts to drinking water resources. The data will also be evaluated to consider the potential for impacts to arise after the study period.

Contribution: Because baseline data can be collected, comparisons can be made between the conditions of drinking water resources prior to and at all stages of the hydraulic fracturing water cycle, and for up to a year after hydraulic fracturing occurs. Collecting samples as hydraulic fracturing is occurring also provides the opportunity to more directly observe the behavior of hydraulic fracturing fluids in the environment throughout the fracturing lifecycle.

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Q: What is the current status of the prospective case studies?

A: We have worked closely with industry partners to try and identify suitable locations for prospective case studies that meet the scientific needs of the study and industry's business needs. We continue to explore opportunities and so far we have not identified a suitable location. For a location to be suitable, it is necessary to gather a minimum of one year of characterization data for ground water and surface water prior to and following unconventional exploration activities in the study area, and for there to be no other hydraulic fracturing activities on adjacent properties during the entire study period, which could last several years.

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Analysis of Existing Data

Q: In the analysis of existing data, will EPA be considering recently published studies of the relationship between hydraulic fracturing and drinking water resources?

A: Yes, relevant, peer-reviewed studies will be considered in the report.

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Q: Is EPA incorporating ongoing ground water investigations, such as the ones in Pavillion, WY and Dimock, PA, into this study?

A: Ground water investigations are distinct from the retrospective and prospective case studies conducted as a part of this study, and so they cannot be used as case studies. EPA is applying the Agency’s assessment factors for evaluating the quality of all scientific and technical information considered in the Hydraulic Fracturing Study.

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Q: How can the public contribute information to the study?

A: In fall 2012, EPA published a Federal Register Notice, establishing a docket where stakeholders could submit relevant data and scientific literature to ensure that EPA is up-to-date on evolving industry practices and technologies. The submission deadline was extended from April to November 2013, to provide the public with more of an opportunity to provide feedback to the Agency. All submissions to the docket can be viewed here.

EPA is currently considering all submissions. Consistent with the Agency’s commitment to using the highest quality information in its scientific assessments, EPA prefers information that has been peer reviewed.

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Q: How is EPA analyzing chemicals that are protected by confidential business information rules?

A: EPA is working closely with the companies that provided information to determine how best to summarize the results of this effort so that Confidential Business Information (CBI) is protected while upholding the agency's commitment to transparency. 

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Q: What information will the study provide about the identity and concentration of chemicals used in hydraulic fracturing fluids?

A: Appendix A of the Progress Report, released in December 2012, includes a list of over 1,000 unique chemicals reported to have been used in hydraulic fracturing fluids or detected in hydraulic fracturing wastewater. Sources of information include federal and state government documents, industry-provided data, and other reliable sources. In evaluating the sources, EPA considered whether reports relied upon a clear, scientific methodology and had verifiable original sources. (The complete list of sources for the information in Appendix A is available on page 245 of the report). EPA has limited information on the concentrations of chemicals being used in hydraulic fracturing and is currently reviewing these data.

In the draft assessment report, EPA plans to provide a table that outlines the known chemical, physical and toxicological properties of each chemical listed. If this information is not available from the literature, EPA will estimate properties based on the chemical structures.

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Q: How did EPA select the oil and gas operators that are providing data for the study?

A: Prior to selection, the nine hydraulic fracturing service companies that responded to an information request provided a list of approximately 1,100 companies that together own or operate roughly 25,000 oil and gas production wells that were hydraulically fractured during 2009-2010. Using the list of 25,000 wells, EPA selected nine operators using a stratified random process to represent diversity in both geography and operator size. From the wells associated with the nine operators, EPA randomly selected a subset that approximates the geographic diversity of wells hydraulically fractured in the continental U.S by the nine hydraulic fracturing service companies.

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Environmental Justice

Q: What is the status of the Environmental Justice screening?

A: During the study’s planning process, some stakeholders raised concerns about environmental justice and hydraulic fracturing, while others stated that hydraulic fracturing-related activities provide benefits to local communities.

The EPA attempted to conduct a screening to provide insight into whether hydraulic fracturing occurs more often near communities with environmental justice concerns. However, the Agency was not able to identify comprehensive, sufficient, and consistent data sources at the appropriate scale for an environmental justice analysis. Further research on environmental justice issues will not be completed as part of the study. For more information, please see chapter 2 of the Progress Report.

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