2015: Fracking in the United States

Hydraulic fracturing, also known as fracking, is a method of oil and natural gas extraction. Fracking involves injecting fluid into subterranean rock formations at high pressure to produce a fracture network that allows crude oil and natural gas inside dense rocks to be extracted at the surface.

  • According to the U.S. Energy Information Administration (EIA), hydraulically fractured wells in the United States increased 1,204 percent—from approximately 23,000 hydraulically fractured wells in 2000 to approximately 300,000 wells in 2015.
  • In 2015, hydraulically fractured wells accounted for 67 percent of U.S. natural gas production and 51 percent of U.S. crude oil production.
  • Proponents of fracking argue that the practice produces economic benefits, such as jobs, higher tax revenue, lower energy prices, and economic growth. Opponents of fracking argue that its environmental impacts, such as air pollution and potential effects on water resources, justify greater federal and/or state regulation.

See the sections below for further information on the following topics:

  • Background: This section summarizes the basics of fracking, the estimated number of hydraulically fractured wells, and the history of fracking.
  • Federal fracking policies: This section summarizes how fracking is regulated at the federal level.
  • Support and opposition: This section summarizes arguments from both proponents and opponents of fracking.
  • Economic impact: This section summarizes a variety of studies to calculate the economic effects of fracking.
  • Environmental impact: This section summarizes discussions of the various environmental impacts of fracking.
  • Oil and gas production: This section summarizes oil and natural gas production (which includes production with and without fracking) in the United States.


See also: Fracking
Well field in Odessa, Texas

Hydraulic fracturing, also known as fracking, is a method of oil and natural gas extraction. The process involves injecting fluid into subterranean rock formations at high pressure. The high-pressure fluid produces a fracture network that allows crude oil and natural gas inside dense rocks to flow into a wellbore and be extracted at the surface. The fluid (known as frac fluid) contains between 98 percent and 99.5 percent water and sand; between 0.5 percent and 2 percent of the fluid is composed of chemical additives, which are used to stop the growth of microorganisms, prevent well casing corrosion, increase the rate at which the fluid is injected, and reduce pressure, among other things.

According to the U.S. Energy Information Administration (EIA), the United States had approximately 23,000 hydraulically fractured wells in 2000. In 2015, the United States had approximately 300,000 hydraulically fractured wells, which accounted for 67 percent of U.S. natural gas production and 51 percent of U.S. crude oil production. According to the EIA, increased U.S. natural gas production from 2000 to 2015 „was mainly the result of horizontal drilling and hydraulic fracturing techniques, notably in shale, sandstone, carbonate, and other tight geologic formations.“

The charts from EIA below show total crude oil and natural gas production from hydraulically fractured wells and non-fracked wells.



Data was compiled by the U.S. Energy Information Administration.
Data was compiled by the U.S. Energy Information Administration.

History of fracking

The process of fracking was first studied by the Stanolind Oil and Gas Corporation in the 1940s. Fracturing was used experimentally in Kansas in 1947 to extract natural gas from limestone. Beginning in 1949, this experimental technology was used commercially by Halliburton, an oilfield service company. Fracking applications increased during the 1950s. In the mid-1950s, over 3,000 existing wells were hydraulically fractured per month. In 1970, downhole motors (mud motors) were developed to allow drill operators to adjust the drill string in order to drill wells horizontally. By the 1970s, natural gas extraction began to decline. Additionally, the Organization of the Petroleum Exporting Countries (OPEC) imposed a ban on petroleum exports to the United States and cut oil production, leading to rising gasoline prices in the United States. In response, Congress passed the Energy Policy and Conservation Act (EPCA), which banned crude oil exports to facilitate increased domestic crude oil production.


During this time, the U.S. Department of Energy initiated funding for microseismic mapping and data accumulation projects related to the production of unconventional natural gas sources. In the 1980s and 1990s, George Mitchell, head of Mitchell Energy & Development Corp., invested between $7 million and $8 million to research and develop fracking and horizontal drilling and to extract natural gas in the Barnett Shale of Texas.


According to the U.S. Geological Survey, „There have been significant advancements in both drilling and treatment fluids since their initial applications, most strikingly since 2000.“ Between 2000 and 2010, companies began using different types of frack fluid and additives during the fracking process to enhance oil and gas recovery. From 2007 to 2009, fracking spurred by new treatment fluids and additives led to increased shale gas production in states outside Texas, such as Pennsylvania, Ohio, West Virginia, and North Dakota. These developments allowed oil and gas producers to drill into shale reservoir rocks that were previously believed to be too impermeable or costly to drill.


The maps below show the distribution of approximately 987,000 hydraulically fractured wells drilled in the contiguous United States from 1947 to 2010 (left) and approximately 278,000 hydraulically fractured wells drilled in the contiguous United States from 2000 through 2010 (right).


Fracking policies

See also: Oil and natural gas extraction on federal land


While state governments generally have the primary regulatory authority over fracking within their borders, oil and natural gas companies must comply with requirements in various federal laws on environmental protection and public safety. These laws include the Clean Air Act (limiting air pollution), the Clean Water Act (limiting the discharge of pollutants into navigable waters), the Resource Conservation and Recovery Act (which regulates disposal of hazardous wastes), the Comprehensive Environmental Response, Compensation, and Liability Act (which regulates the cleanup of hazardous spills). State governments generally regulate fracking operations in the following areas:

  • Well construction, casing, and cementing
  • Protection of underground and surface water
  • The reporting and disclosure of the types of fluids used in fracking and at what volume and a description of each chemical additive used in fracking
  • The maximum amount of surface and injecting pressure used during the process
  • Spill prevention and clean-up
  • All other information considered necessary for the regulation of fracking for safety and environmental protection

After Congress passed the 1974 Safe Drinking Water Act (SDWA), the Environmental Protection Agency (EPA) interpreted the law to exclude fracking from the act’s underground injection program for oil and natural gas-related wells, claiming that fracking did not fall under the program’s requirements. Specifically, the agency argued that the purpose of fracking was to extract natural gas and not to inject fluids into a well, the latter of which is regulated under the federal underground injection program. In 1997, the U.S. Court of Appeals for the 11th Circuit ruled that the use of fracking to extract coalbed methane in Alabama was underground injection subject to Safe Drinking Water Act regulations.


After the ruling, the EPA studied the potential health and safety impacts to drinking water supplies from fracking for coalbed methane, concluding in 2004 that risks were minimal (unless diesel fuel was used) and that regulation of fracking under the Safe Drinking Water Act’s injection program was unnecessary.

In the Energy Policy Act of 2005, Congress revised the Safe Drinking Water Act (SDWA) to exclude „the underground injection of fluids or propping agents (other than diesel fuels) pursuant to hydraulic fracturing operations related to oil, gas, or geothermal production activities” from the Safe Drinking Water Act’s requirements for the underground injection control (UIC) program. The 2005 act effectively allows state governments to regulate fracking as the process relates to underground drinking water sources, though state regulations must meet the minimum requirements outlined in all applicable federal laws, such as the Clean Air Act, Clean Water Act, and others.

Production on federal land

Companies seeking permission to extract oil or natural gas on federal land, whether or not fracking is used, must submit an application containing a drilling plan, a surface use plan, information on drilling locations, a plan for containing and disposing waste, and plans for surface reclamations (restoring land to its original state prior to drilling operations). In fiscal year 2015, an application to develop oil or natural gas on federal land took an average of 220 days to process (to approve or deny). Generally, state agencies process applications for oil and natural gas development on private land within their states in less time than the federal government, though the comparison between the permitting processes for private land and federal land „does not lend itself to an ‚apples-to-apples‘ comparison,“ according to the Congressional Research Service.

Trump administration (2017-2020)

For information about actions taken by the Trump administration regarding energy policy, including fracking, see the articles below:

Obama administration (2009-2017)

Fracking rule for federal land

In March 2015, the Obama administration issued a final agency rule regulating fracking on federal land. The rule would have required oil and gas operators to receive approval from the U.S. Bureau of Land Management (BLM) for fracking on federal land; receive BLM verification of well casing for safety and adequacy; monitor, record, and report pressure within well casing; and provide notification to the BLM of and make publicly available all non-trade secret chemicals used during fracking.


Opponents of the rule, such as the Independent Petroleum Association of America and the Western Energy Alliance, filed suit against the Interior Department, arguing that the Interior Department had no congressional authority to issue the rule. Proponents of the rule, such as the Sierra Club, filed a brief supporting the Interior Department, arguing that the Mineral Leasing Act of 1920 gave broad authority to the federal government to regulate all oil and gas operations on federal land. The lawsuit was filed by the states of Colorado, North Dakota, Utah, and Wyoming.


In September 2015, Judge Scott W. Skavdahl of the U.S. District Court for Wyoming temporarily blocked the rule from going into effect. Skavdahl wrote, „The fracking rule creates an overlapping federal regime, in the absence of congressional authority to do so, which interferes with the states’ sovereign interests in, and public policies related to, regulation of hydraulic fracturing.“ In June 2016, Skavdahl officially struck down the rule, arguing that the BLM had no congressional authority to issue the rule under existing federal law. In reversing the rule, Judge Skavdahl wrote that Congress‘ exclusion of fracking from regulation by the Environmental Protection Agency (EPA) in the Energy Policy Act of 2005 „indicates clearly that hydraulic fracturing is not subject to federal regulation.“ In addition to the above four states, Alaska, Kansas, Montana, and Texas filed an amicus brief in the United States Court of Appeals for the 10th Circuit opposing the BLM’s rule.

Support and opposition

Proponents argue that the use of fracking has created jobs, lowered energy prices, spurred economic growth, and provided increased tax revenue at all governmental levels. Additionally, proponents argue that fracking has few health and safety risks and that these potential risks have been and continue to be effectively regulated at the state level.


Opponents of fracking argue that the process has known and unknown environmental impacts and should be more heavily regulated, particularly at the federal level, or banned altogether. Additionally, opponents argue that the energy industry cannot be relied on to voluntarily protect the environment and thus require additional regulation, particularly at the federal level.


  • In an April 2013 article for the Century Foundation, a self-described progressive think tank whose mission is “to foster opportunity, reduce inequality, and promote security at home and abroad,” Charles R. Morris argued that growth in shale-based energy extracted through fracking could lead to fewer energy trade deficits and „a boom in energy-intensive manufacturing, like chemicals, steel, fertilizers, and paper.“ Morris wrote, „The shale industry itself is a bonanza of middle-class blue-collar jobs, and the prospect of a reindustrializing America promises many more.“ Morris also argued that the shale industry would have to adopt extensive quality control and reporting systems to ensure environmental protection. Specifically, Morris argued that the shale industry should adopt comprehensive practices to address „surface spills, water management, well casing, pre- and post-environmental status reporting, and much else.“
  • In an article entitled „What is Fracking?“, the Western Energy Alliance, a self-described nonprofit trade association representing more than 300 oil and natural gas companies, argued that the oil and gas industry uses specific measures during fracking and other extraction operations to prevent damage to the environment, including the installation of multiple cement and steel layers to protect drinking water sources. The WEA also cited a 2012 study from the National Academies concluding that fracking does not pose a high risk for felt earthquakes. The WEA also argued that states governments have successfully regulated fracking since 1949. According to the WEA, „Fracking has been performed in more than 1.2 million wells since 1949 with an exemplary safety record and no documented cases of contamination of drinking water.“ The WEA argued that additional federal regulations are thus unnecessary given existing state regulations.
  • In a November 2016 article, the Institute for Energy Research, whose stated mission is to perform „intensive research and analysis on the functions, operations, and government regulation of global energy markets“, argued that a national ban on fracking would reduce economic benefits for producers and consumers and would raise energy prices, reduce the global supply of oil, and cause the United States to become a natural gas importer rather than exporter. The institute cited a November 2016 study published by the U.S. Chamber of Commerce, an organization that supports fracking. The 2016 study’s authors found that a national fracking ban would reduce U.S. jobs by 14.8 million, double electricity and gasoline prices, increase cost of living expenses by approximately $4,000, and reduce household incomes by $873 billion by the year 2022.


  • In a March 2015 study, Food and Water Watch, whose stated mission is to „stand up to corporations that put profits before people, and advocate for a democracy that improves people’s lives and protects our environment“, argued that fracking should be banned due to its environmental impacts, such as land clearings to make room for well sites and pipelines, accidents, leaks, and spills that can harm streams, rivers, and groundwater, air pollution at well sites, and an increasing use of freshwater for fracking operations. In addition, the report’s authors argued that continued use of fracking to extract oil and natural gas would increase greenhouse gas emissions linked to potentially human-caused climate change. The authors concluded that „stringent regulations, even if put in place and even if adequately enforced, would not make fracking safe“ and that „federal- and state-level action is necessary to reverse the spread of fracking.“
  • In a 2012 study, Environment America, whose stated mission is „to commit our country to 100% renewable energy, [and] keep fossil fuels in the ground“, among other initiatives, argued that the environmental costs of fracking, such as the potential for spills and well failures, air pollution at well sites, and cleanup costs in case of accidents, justify greater regulation as well as fees and penalties on the oil and gas industry. According to the study’s authors, „[F]ederal, state and local governments should hold the oil and gas industry accountable for the costs of fracking“ by requiring companies to post bonds to pay for plugged wells, any physical damage to land, and full compensation to those who may be affected by fracking operations. The report’s authors also argued for more taxes, fees, and other charges on oil and gas companies to „recoup for the public some of the costs imposed by fracking“ and to incentivize these companies to reduce their environmental impact.
  • In a June 2013 article for the Center for American Progress, whose stated mission is to promote „bold, progressive ideas, as well as strong leadership and concerted action“, Tom Kenworthy argued that fracking could contribute to strains in water supply and use. Kenworthy cited a May 2013 study by Ceres, a nonprofit group whose stated mission is „to build a sustainable future for people and the planet.“ The study found that, out of 25,000 wells with fracking operations, 47 percent were in areas „with high or extremely high water stress“ due to water withdrawals by oil and gas operators, agriculture, and municipalities. The study’s authors found that, while fracking may account for between 1-2 percent of each state’s water use, water used for fracking can be higher at the local level and thus increase competition for dwindling freshwater supplies.

Economic impact

A rig worker in Williston, North Dakota

The following section summarizes the economic impacts of fracking and various studies that analyze these impacts. The studies below measured the economic impact of oil and natural gas as a whole, as studies focusing solely on the economic effects of hydraulically fractured wells versus non-fracked wells were generally unavailable as of August 2017.


To calculate the economic impact of greater oil and gas extraction, economists use forecasting models. Economic studies generally measure both direct impacts, which include the jobs and income added directly by the oil and gas industry, and the indirect impacts, which include the jobs and income generated by the production and distribution of oil and gas. These studies also include induced impact, which includes the jobs and income generated by serving or assisting the industry directly (such as restaurant chains that serve oil and gas workers).


Congressional Budget Office study (2014)

In December 2014, the Congressional Budget Office (CBO), a federal office that provides budgetary information to Congress, published a study on the economic and budgetary effects of increased oil and natural gas production, including increased fracking use.


The study’s authors argued that natural gas costs in the year 2040 would be 70 percent higher without the increased development of natural gas through fracking. The authors also found that Pennsylvania, New York, and West Virginia) accounted for 25 percent of total recoverable shale gas, followed by the Haynesville-Bossier Shale in Texas and Louisiana at 15 percent, the Eagle Ford Shale in Texas at 10 percent, and the Barnett Shale in Texas at 10 percent (as of December 2014). The CBO report also found that the Eagle Ford and Austin Chalk Shales (both in Texas) accounted for 40 percent of recoverable shale oil (crude oil found in shale formations), followed by the Bakken Shale in North Dakota and Montana at 20 percent (as of December 2014).

U.S. Energy Information Administration study (2013)

A 2013 study from the U.S. Energy Information Administration (EIA) found that oil and natural gas industry employment increased faster than total private sector employment between the years 2007-2012. The study found that oil and gas employment increased by more than 162,000—a 40 percent increase—compared to an increase of more than 1 million jobs in the private sector during the same period—a 1 percent increase. Of total private sector employment growth from 2007-2012, oil and natural gas employment accounted for approximately 16 percent. According to the EIA, oil and natural gas employment equaled roughly one-half of one percent of total U.S. private sector employment at the end of 2012.


The study’s breakdown of oil and natural gas employment at the end of 2012 can be found below:

  • Drilling jobs accounted for more than 90,000 jobs by the end of 2012—an increase of 6,600 jobs since 2007. Drilling employment includes any work related to the drilling and reworking of wells.
  • Extraction jobs accounted for 193,000 jobs—an increase of 53,000 jobs from 2007-2012. Extraction employment involves operating, developing, and producing natural gas and oil. It also includes exploration and all production work up to the point of shipping oil and gas from producing areas.
  • Support jobs in the oil and gas industry accounted for more than 286,000 jobs—an increase of 102,000 jobs from 2007-2012. Support employment was the largest category of oil and natural gas employment and accounted for approximately half of all workers in the oil and natural gas industry in 2012. These jobs include any supporting activities for oil and natural gas operations, such as exploration, excavation, well surveying, casing work, and well construction. This number excludes jobs created in other industries, such as manufacturing, housing, retail, education, and food services that may have resulted from increased oil and gas employment.

According to the EIA, oil and gas employment helped grow overall private sector employment following the 2007-2009 recession. The support and drilling sectors in particular were negatively affected by the 2007-2009 recession but recovered following the recession’s end in October 2009, according to the EIA. From 2007-2012, monthly crude oil production in the United States increased by 39 percent while monthly natural gas production increased by 25 percent.

IHS Markit study (2013)

A September 2013 study published by IHS, which the organization describes is dedicated to „next-generation information, analytics and solutions to customers in business, finance and government,“ concluded that an increase in unconventional oil and natural gas production (which includes production that uses fracking) increased disposable income per U.S. household by an average of $1,200 in the year 2012. The study’s authors argued that this increased income came in the form of lower energy bills and lower costs for goods and services. Additionally, the study’s authors argued that up to 250,000 jobs could be created by the year 2020 due to fracking. The full study can be accessed here.

American Petroleum Institute study (2013)

A July 2013 study by the American Petroleum Institute, whose stated mission is „to influence public policy in support of a strong, viable U.S. oil and natural gas industry essential to meet the energy needs of consumers in an efficient, environmentally responsible manner“, found that the oil and natural gas industry supported 9.8 million jobs in 2011. Of these jobs, 2.6 million were supported through direct employment in the industry, 5.9 million through indirect and induced employment in oil and gas-related operations, and 1.4 million through capital investments. In total, the study found that the oil and natural gas industry accounted for 5.6 percent of total employment in the United States. Altogether, the industry accounted for $597.6 billion in labor income and $1.21 trillion in value added in 2011 (value added includes employee compensation, proprietors‘ income, income to capital owners from a property, and indirect business taxes). The top 15 states with the largest oil and gas direct employment used in the study are listed below.

American Enterprise Institute study (2013)

A February 2013 study by Aparna Mathur and Kevin A. Hassett at the American Enterprise Institute, which is a self-described „community of scholars and supporters committed to expanding liberty, increasing individual opportunity and strengthening free enterprise,“ found that direct economic benefits from increased gas production by fracking generated approximately $36 billion in economic activity in 2011 (multiplying total U.S. natural gas production of 8.5 trillion cubic feet of natural gas in 2011 by an average price of $4.24 per thousand cubic feet). The authors argued that this economic value can lead to higher employment in the gas production and delivery sectors. The complete study can be accessed here.

Taxes, fees, and revenue

Fracking proponents argue that increased oil and gas production can generate more local government revenue collected through property and sales taxes. The primary revenue streams from fracking include mineral leasing revenues, which is the income generated to those who lease their property to oil and gas developers, and severance taxes, which go to the states and the federal government. Severance taxes are intended to compensate present and future citizens of a state where oil and gas is extracted. The pie chart below shows the U.S. average for each tax revenue source for 2014. Severance taxes accounted for an average of 3.4 percent of all state tax revenue collected in 2014.


Alaska had the largest percentage of its total revenue come from severance taxes—85.73 percent—followed by North Dakota (61.41 percent), Wyoming (53.56 percent), New Mexico (22.84 percent), and Montana (20.12 percent). Texas generated the most revenue from severance taxes with approximately $6 billion. Three other states brought in over $1 billion in revenue from severance taxes: North Dakota, Alaska, and New Mexico.

Royalties, land sales, and prices

In fiscal year 2015, the federal government collected $3.7 billion in royalties, rents, bonuses, and other revenue for onshore energy production on federal land. Of that total, $3.18 billion came as royalties from onshore oil, coal, and natural gas production. That same year, the federal government collected $5.09 billion in royalties, rents, bonuses and other revenue for offshore energy production on federal land. Of that total, $4.25 billion came from royalties on offshore oil and natural gas production.


Although the federal government does not collect data on oil and natural gas royalty and land sales on private land, a March 2014 study by Timothy Fitzgerald of Texas Tech University and Randal R. Rucker of Montana State University made the following estimates for oil and gas-related royalties, land sales, and prices for private land in 2012:

  • Royalty owners were paid $22 billion for the rights to their minerals;
  • Private minerals were worth $161 billion;
  • The top four states with the largest royalties were Texas, California, Louisiana, and Oklahoma; and
  • 77 percent of onshore oil and natural gas revenue came from minerals that were leased to oil and gas companies by private individuals or groups.

The table below shows estimated private oil and gas revenues and royalties in 2010 by state. All the data presented below are in millions of nominal dollars.

Environmental impact

The following section summarizes the environmental impacts of fracking and various studies that analyze these impacts, particularly induced seismicity (earthquakes) and potential water impacts. Other impacts (air and land impacts) are also described below.


Human-induced earthquakes can be caused by mining, damming rivers, and creating injection wells, such as those used during oil and gas extraction. These earthquakes are caused by injection wells when water pumped into underground wells causes the faults under the earth to slip. After a well has been fracked, water returns to the earth’s surface. Water that cannot be recycled or reused is generally stored in injection wells, which are located thousands of feet underground and encased in cement. Multiple oil and gas wells generally rely on at least one disposal well for wastewater storage.


As of October 2016, earthquakes from underground fluid injection during oil and gas production had been small—between 2.0 or 3.0 in magnitude on the Richter scale, according to the U.S. Geological Survey (USGS). Scientists at the USGS have also generated earthquakes intentionally by carefully injecting liquid into the earth. As of July 2017, Colorado, Kansas, Ohio, Oklahoma, and Texas established seismic monitoring stations and updated injection well regulations, among other actions, to address increased seismic activity from fluid injections.


In 2014, the U.S. Geological Survey argued that fracking was not the main cause of felt earthquakes in most instances:

USGS’s studies suggest that the actual hydraulic fracturing process is only very rarely the direct cause of felt earthquakes. While hydraulic fracturing works by making thousands of extremely small ‚microearthquakes,‘ they are, with just a few exceptions, too small to be felt; none have been large enough to cause structural damage. As noted previously, underground disposal of wastewater co-produced with oil and gas, enabled by hydraulic fracturing operations, has been linked to induced earthquakes.
—U.S. Geological Survey


In 2016, the USGS found that wastewater disposal, rather than fracking, was the main cause of an increase in earthquakes throughout the central United States from 2009 to 2013. According to the agency, wastewater disposal wells raise pressure levels more than fracked wells. Larger amounts of fluid are used in wastewater disposal wells than in fracked wells; thus, wastewater disposal wells were more likely to produce induced seismic events than fracked wells, according to the agency. In addition, the agency argued that wastewater injection and as a result induced seismic activity typically occurs in rocks that have not been previously touched, whereas fracking involves injecting fluid into rock layers from which oil and natural gas have previously been extracted. The USGS concluded that induced seismic events are more likely to occur in rock formations that have not been touched than formations that had been subjected to oil and gas activities.


In March 2014, four seismic events (ranging between 2.2 magnitude and 3 magnitudes on the Richter scale) were identified by the USGS in Poland Township, Ohio, near a fracking operation. The Ohio Department of Natural Resources (ODNR) temporarily halted the operations and conducted an investigation, which concluded that there was likely a connection between fracking and the seismic events. These seismic events occurred on a previously unknown micro-fault. The ODNR announced it would require oil and gas operators to follow additional permit conditions and would begin to monitor and address induced seismicity potentially linked to fracking in the state. The ODNR also said that it would work with private interstate oil and gas commissioners, states, and other stakeholders to share relevant data on induced seismicity and fracking. In addition, Ohio state regulators implemented a seismic monitoring system for certain disposal wells, particularly in areas where the surrounding geology could increase the likelihood of induced seismicity. Seismic monitors are used on a site-by-site basis; if induced seismic events are not detected prior to and after injection, the seismic instruments may be transferred elsewhere.


Aerial view of oil and gas wells in the Raton basin


2016 EPA study on fracking

See also: The EPA study on fracking and drinking water resources (2016)

Congress in 2010 directed the EPA to review available research on the impacts of fracking on drinking water resources. The EPA study plan was released in November 2011, and the final report was released in December 2016.


A review draft of the report was issued in June 2015, along with a press release headlined: “Assessment shows hydraulic fracturing activities have not led to widespread, systemic impacts to drinking water resources and identifies important vulnerabilities to drinking water resources.” The draft’s summary of major findings stated:

From our assessment, we conclude there are above and below ground mechanisms by which hydraulic fracturing activities have the potential to impact drinking water resources. These mechanisms include water withdrawals in times of, or in areas with, low water availability; spills of hydraulic fracturing fluids and produced water; fracturing directly into underground drinking water resources; below ground migration of liquids and gases; and inadequate treatment and discharge of wastewater.

We did not find evidence that these mechanisms have led to widespread, systemic impacts on drinking water resources in the United States. Of the potential mechanisms identified in this report, we found specific instances where one or more mechanisms led to impacts on drinking water resources, including contamination of drinking water wells. The number of identified cases, however, was small compared to the number of hydraulically fractured wells.


Following the release of the draft, the EPA’s Science Advisory Board (SAB) reviewed the report and submitted comments to the agency. In its 180 pages of comment, the board questioned the basis for the draft conclusion, stating, “The SAB finds that the EPA did not support quantitatively its conclusion about lack of evidence for widespread, systemic impacts of hydraulic fracturing on drinking water resources, and did not clearly describe the system(s) of interest (e.g., groundwater, surface water), the scale of impacts (i.e.,local or regional), nor the definitions of ‘systemic’ and ‘widespread.’”


The conclusion in the EPA’s final report published in December 2016 stated:

The available data and information allowed us to qualitatively describe factors that affect the frequency or severity of impacts at the local level. However, significant data gaps and uncertainties in the available data prevented us from calculating or estimating the national frequency of impacts on drinking water resources from activities in the hydraulic fracturing water cycle. The data gaps and uncertainties described in this report also precluded a full characterization of the severity of impacts.


Concerning the draft conclusion that researchers did not find evidence of widespread, systemic impacts from fracking on drinking water resources, the draft noted the following:

This finding could reflect a rarity of effects on drinking water resources, but may also be due to other limiting factors. These factors include: insufficient pre- and post-fracturing data on the quality of drinking water resources; the paucity of long-term systematic studies; the presence of other sources of contamination precluding a definitive link between hydraulic fracturing activities and an impact; and the inaccessibility of some information on hydraulic fracturing activities and potential impacts.


In the final report, such data gaps were presented as inhibiting a conclusion about national impacts.

2015 Science study

A 2015 article published in Science reviewed 11,309 water wells across Pennsylvania and found that „background levels of methane in the water are unrelated to the location of hundreds of oil and gas wells that tap hydraulically fractured, or fracked, rock formations.“ This study contradicted a 2011 study published by researchers of Duke University that had used smaller water well sample sizes—between 60 water wells and 114 water wells—to conclude that „wells closer to fracking sites had higher levels of methane.“ The authors of the 2015 Science study critiqued the Duke study and similar studies for using wells that were known to have been poorly constructed and that could have caused methane to migrate into drinking water wells. According to the 2015 Science article, „[F]or all their disagreements, scientists on both sides of the fracking debate agree that it is very unlikely that microfracturing of rock formation itself contributes to the vertical migration of gases.“

National Academy of Sciences study (2014)

A 2014 study published in the Proceedings of the National Academy of Sciences analyzed water well samples from both the Marcellus and Barnett shales, located in Pennsylvania and Texas, respectively. Researchers found that higher-than-expected levels of hydrocarbon gases, including methane, had not been caused by fracking, or horizontal drilling, but by well integrity problems. Researchers gathered 113 samples from Pennsylvania and found seven instances of fugitive gas contamination, known as elevated hydrocarbon levels. In Texas, 20 wells were sampled, and one instance of fugitive gas contamination was found. Of these eight cases, four were identified by the researchers as having likely been caused by poor well cementing, not fracking. Three cases were associated with faulty casing, and the final well experienced underground well failure. The study also found that methane in wells above the Marcellus Shale occurred naturally and was not the product of fracking.

Department of Energy study (2011)

An August 2011 study by the U.S. Department of Energy found that the „likelihood of properly injected fracturing fluid reaching drinking water through fractures is remote“ when a large separation exists between drinking water sources and the areas where oil and gas are produced.

According to the department, the majority of regions where shale gas production occurs are largely separated from drinking water sources and that there was little to no documentation of fracturing fluid migrating to drinking water sources.

According to Mark Zoback, professor of geophysics at Stanford University and a member of the committee responsible for the report (the Shale Gas Production Subcommittee at the Energy Department), „[F]racturing fluids have not contaminated any water supply and with that much distance to an aquifer, it is very unlikely they could.“ Zoback said that injection is performed at depths ranging from 6,000 feet and 7,000 feet and that drinking water is taken from aquifers 100 feet to 200 feet below the surface. Zoback claimed that, though natural gas has been found in drinking water supplies in some instances, the problem was caused primarily by poor well construction. For example, if a steel well’s casing is not full cemented, natural gas can leak „around the outside of the casing and contaminate shallow aquifers.“ According to Zoback, aquifers contaminated by natural gas are usually linked to „leaking casings of very old wells that predate recent drilling for natural gas by 40 or 50 years.“

Zoback identified the disposing of water that flows out of a well after it has been fracked as a concern since the water can contain arsenic, iron, and selenium. According to Zoback, one solution includes injecting the water into a storage well that meets federal and state standards to prevent leakage. Zoback also argued that a preferable method is to treat the water for reuse and return it to the shale from which it came, a process that occurs in fracking operations in the northeastern United States.

MIT study (2010)

A 2010 study by researchers at the Massachusetts Institute of Technology (MIT) found that no reported incidents „conclusively demonstrate the contamination of shallow water zones with fracture fluids.“ Researchers argued that out of 43 widely reported incidents of water contamination, approximately half appeared to be related to the contamination of shallow water zones with natural gas, and around one-third of the reported incidents were related to on-site surface spills.

State government studies

Studies from state government agencies on the impact of fracking on drinking water within their states are summarized below:

  • A January 2011 study by regulators at the Ohio Department of Natural Resources did not find „a single instance where ground has been contaminated by hydraulic fracturing operations“ in the approximately 80,000 wells that were hydraulically fractured in the state as of January 2011.
  • A September 2011 study by regulators at the New York Department of Environmental Conservation found that it was „highly unlikely that groundwater contamination would occur by fluids escaping from the wellbore for hydraulic fracturing.“ Additionally, regulators in 15 other states testified that groundwater contamination as a result of fracking processes had not occurred.
  • In a September 2012 report from the U.S. Government Accountability Office, regulatory officials in Arkansas, Colorado, Louisiana, North Dakota, Ohio, Oklahoma, Pennsylvania, and Texas testified that state investigations did not find fracking as a cause of groundwater contamination within their states.

Other environmental impacts

As with any type of energy extraction, air pollution can occur throughout the oil and gas extraction process. In the case of fracking, air pollution can occur when oil or natural gas is extracted, transported, or distributed. Pollutants that may be emitted include volatile organic compounds, hydrogen sulfide, polycyclic aromatic hydrocarbons, and particulate matter.

Fracking involves directional drilling, which is used to create non-vertical wells to access resources that are inaccessible by drilling a vertical well. Directional drillers increase their control over the angle of wells and can adjust the angle of a drill bit, and thus the well’s angle, in real time.


Proponents of fracking argue that one environmental benefit of directional drilling is the ability of operators to access energy resources in sensitive areas without having to set up multiple vertical wells on a stretch of land. Proponents also argue that drillers can create one horizontal well to access to large deposits of oil or gas deposits that would otherwise require several vertical wells.


As a result, proponents argue that visible construction and land changes are reduced and access to reserves is increased without harming sensitive areas. Opponents argue that fracking still results in land damage, including clearing land and forests for roads, wells, pipelines, and other infrastructure.


Opponents argue that these land changes negatively affect local habitats and species and disrupt public access to forests and open landscapes. Opponents further argue that continued fracking leads to more oil and gas activity near forests and farmland. As a result, opponents argue that fracking reduces or eliminates natural resources by converting forests and agricultural land into drilling sites.

Oil and gas production

Approximately 21 percent of U.S. crude oil production in 2015 was on federal land, while 79 percent occurred on state and private land. Approximately 16 percent of U.S. natural gas production in 2015 was on federal land, while 84 percent was on state and private land. According to the U.S. Energy Information Administration (EIA), wells that had been hydraulically fractured accounted for 51 percent of the crude oil and 67 percent of the natural gas produced in the United States in 2015.


See also: Energy production in the United States.
Note: This section includes oil and gas production from private and state-owned lands. Information on oil and gas production on federal lands is available here.

Crude oil production by state
A darker color indicates more production. Scroll over a state to view its percentage of total U.S. crude oil production in 2016. States in white had no production.


Natural gas production by state
A darker color indicates more production; scroll over a state to view its percentage of total U.S. natural gas production in 2015. States in white had no production.

Click the [Show] button to view the table below. (Note: Unlike crude oil production data, natural gas production data for all states in 2016 was unavailable as of August 2017)


Coalbed methane is methane contained in layers of coal; it can be used in the same manner as traditionally extracted natural gas. Click the [Show] button on the table below to see coalbed methane production in each state.


Shale gas is natural gas found in shale plays. Click the [Show] button below to see shale gas production in each state.


Oil and gas wells

Crude oil wells by state
A darker color indicates more crude oil wells; scroll over a state to view its percentage of total crude oil wells in 2009. States in white had no oil wells.

Texas ranked first in the number of crude oil wells in 2009, accounting for 39.31 percent of all wells. California ranked second with 13.65 percent. According to the U.S. Energy Information Administration (EIA), 17 states had no crude oil wells in 2009. As of August 2017, the latest EIA crude oil well data was for the year 2009. Click the [Show] button below for more information about crude oil wells in the United States.

Natural gas wells by state
A darker color indicates more natural gas wells; scroll over a state to view its percentage of total natural gas wells in 2015. States in white either had no natural gas wells or no gas well data available for 2015.

According to the U.S. Energy Information Administration (EIA), 20 states had no natural gas wells in 2015. Texas ranked first in natural gas wells, followed by Pennsylvania, West Virginia, Oklahoma, and Ohio. Click the [Show] button below for more information about natural gas wells in each state.


Injection wells

An example of a Class II injection well

Injection wells are used to store fluid or other substances under the earth. There are a variety of injection wells, some of which are shallow and used to store water and non-hazardous liquids. One type, Class II wells, is used to store saltwater and other fluids produced during the oil and gas extraction process. In 2015, 33 states had Class II injection wells. The table below contains data on injection wells in the United States. The map below shows the distribution of injection wells in each state.



Injection wells by state, 2015
A darker color indicates a greater percentage of wells; scroll over a state to view its percentage of wells in 2015. States in white had no injection wells.