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Hydraulic fracturing involves the high-pressure underground injection of large amounts of water and other fluids into gas-bearing rock formations to form fractures that are propped open with sand and/or other materials and chemicals that are also injected. Once the formation is fractured, the natural gas can flow to the well where it is pumped out of the ground. Hydraulic fracturing is a technique that has enabled the production of natural gas from unconventional formations, which represent an increasingly important source of domestically produced gas in the United States.
A single well may be fractured several times, using up to 3 million gallons of water in some locations. Treating and/or disposing of the contaminated flowback water from fracturing operations can pose groundwater and surface water quality management challenges for state regulators and gas developers. Landowners are expressing concern over the potential for contamination of their wells. Some contamination incidents have been reported, but most have been attributed to poor well construction or surface activities, rather than fracturing. However, identifying the cause of contamination can be difficult for various reasons, including the complexity of hydrogeologic evaluations, as well as the confidential business information status given to fracturing fluids in many states.
In the United States, the Safe Drinking Water Act (SDWA) requires controls on the underground injection of fluids to protect underground sources of drinking water. Notwithstanding that general mandate, the law specifically states that Environmental Protection Agency (EPA) regulations for state underground injection control (UIC) programs “may not prescribe requirements which interfere with or impede ... any underground injection for the secondary or tertiary recovery of oil or natural gas, unless such requirements are essential to assure that underground sources of drinking water will not be endangered by such injection.” Consequently, EPA has not regulated gas production wells, and had not considered hydraulic fracturing to fall within the regulatory definition of underground injection. Then, in 1997, the U.S. Court of Appeals for the 11th Circuit ruled that the hydraulic fracturing of coal beds for methane production constituted underground injection and must be regulated. (This decision applied only to Alabama (LEAF v. EPA, 118 F. 3d 1467).) In response to the 1997 court decision and citizen complaints about water contamination attributed to hydraulic fracturing, EPA began to study the impacts of hydraulic fracturing practices used in coal-bed methane (CBM) production on drinking water sources, and to determine whether further regulation was needed. In 2004, EPA issued a final (phase I) report, based primarily on interviews and a review of the available literature, and concluded that the injection of hydraulic fracturing fluids into CBM wells posed little threat to underground sources of drinking water and required no further study; however, EPA noted that very little documented research had been done on the environmental impacts of injecting fracturing fluids.  EPA also noted that estimating the concentration of diesel fuel components and other fracturing fluids beyond the point of injection was beyond the scope of its study. Some Members of Congress and some EPA professional staff criticized the report, asserting that its findings were not scientifically founded.
The 109th Congress also responded to the court’s decision, and amended SDWA, Section 1421(d), to specify that the definition of “underground injection” excludes the injection of fluids or propping agents (other than diesel fuels) used in hydraulic fracturing operations related to oil, gas, or geothermal production activities. This language removed EPA’s authority under SDWA to regulate the underground injection of fluids for hydraulic fracturing purposes.
Since these developments, the use of hydraulic fracturing has increased. So has concern over the potential impact on water resources, particularly in the water-scarce West, and very few studies have been done to evaluate these impacts. Moreover, hydraulic fracturing is becoming important in the development of gas from shale formations in the densely-populated eastern states, creating new concerns about possible gas development threats to underground sources of drinking water, as well as to surface water quality and supply. These formations include the Marcellus shale, which underlies large parts of New York, Pennsylvania, and West Virginia. The U.S. Geological Survey recently noted that, while the extraction technology for this gas resource has advanced in recent years, “the knowledge of how this extraction might affect water resources has not kept pace.” The gas industry believes that state regulations are adequate, and notes that thousands of fracturing jobs have been conducted with few problems. The industry cautions that additional federal regulation is unnecessary and would likely slow domestic gas development and increase energy prices. However, information on reported contamination incidents is largely anecdotal, and some are calling for federal regulation or further study of this activity. Currently the National Academy of Sciences is conducting a study titled “Management and Effects of Coalbed Methane Development and Produced Water in the Western United States.” The project is expected to be completed in mid-2010.
In the 111th Congress, several pending bills address the treatment of hydraulic fracturing under SDWA. H.R. 2300, the American Energy Innovation Act, would express the sense of Congress that SDWA was never intended to regulate natural gas and oil well construction and stimulation, and that the 2005 SDWA amendment clarifying that SDWA was not intended to regulate the use of hydraulic fracturing should be maintained. Companion bills H.R. 2766/S. 1215, entitled the Fracturing Responsibility and Awareness of Chemicals Act, would amend the SDWA definition of “underground injection” to include the underground injection of fluids or propping agents used for hydraulic fracturing operations related to oil and gas production activities. The two bills also would require public disclosure of the chemical constituents (but not the proprietary chemical formulas) used in the fracturing process. Disclosure of a propriety formula to the state, EPA Administrator, or treating physician or nurse would be required in the case of a medical emergency. The House Appropriations Committee report accompanying the Department of the Interior, Environment, and Related Agencies Appropriation Bill, FY2010 (H.R. 2996, H.Rept. 111-180), urges EPA to review the risks that hydraulic fracturing poses to drinking water supplies, using the best available science, as well as independent sources of information.
- ^SDWA Section 1421(b)(2)(B).
- ^ In 2000, a second suit was filed against EPA for approving Alabama’s revised UIC program when it contained several alleged deficiencies. (Legal Environmental Assistance Foundation, Inc. v. U.S. EPA., 276 F.3d 1253 (11th Cir. 2001)). The U.S. Court of Appeals for the 11th Circuit directed EPA to require Alabama to regulate hydraulic fracturing under SDWA. The court determined that EPA could regulate hydraulic fracturing under SDWA’s more flexible state oil and gas provisions in Section 1425, rather than the more stringent underground injection control requirements of Section 1422.
- ^Environmental Protection Agency, Evaluation of Impacts to Underground Sources of Drinking Water by Hydraulic Fracturing of Coalbed Methane Reservoirs, Washington, DC, June 2004, pp. 4-1.
- ^Ibid. p. 4-12.
- ^The Energy Policy Act of 2005 (P.L. 109-58, Section 322).
- ^Daniel J. Soeder and William M. Kappel, Water Resources and Natural Gas Production from the Marcellus Shale, U.S. Geological Survey, U.S. Department of the Interior, Fact Sheet 2009-3032, May 2009, http://pubs.usgs.gov/fs/ 2009/3032/pdf/FS2009-3032.pdf.
Disclaimer: This article is taken wholly from, or contains information that was originally published by, the Congressional Research Service. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the Congressional Research Service should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.
Note: The first version of this article was drawn from RL34201 Safe Drinking Water Act: Selected Regulatory and Legislative Issues by Mary Tiemann, Congressional Research Service on September 2, 2009.