What is Fracking?

Fracking (also often referred to as hydraulic fracturing or hydrofracking) is a process in which a fluid is injected at high pressure into oil or methane gas deposits to fracture the rock above and release the liquid or gas below. The process and its aftermath has generated controversy because of harm to drinking water and health where it has been used, in Colorado and New Mexico [1], and more recently in expanded drilling plans in the Marcellus Shale in New York, Ohio, Pennsylvania and other mid-Atlantic states.[2]

Fracking -- which uses enormous amounts of drinkable water along with toxic chemicals and which also releases radioactive materials and other hazardous substances in shale deposits -- has raised significant environmental and health concerns.[3] In New Mexico, for example, similar processes have leached toxic chemicals into the water table at 800 sites.[4]

The industry lobbied the Bush Administration and Congress with its claims that the "fracking fluid" should be considered "proprietary" and exempt from disclosure under federal drinking water protection laws.[5] Led by Halliburton and aided by the former CEO of Halliburton, then-Vice President Dick Cheney, the industry obtained this exception in the law along with favorable treatment by political appointees and regulators in the "Environmental Protection Agency." As a result of the "Halliburton loophole" to the law, drilling companies have not been required to divulge the cocktail of chemicals that are in the fracking fluids used at each of the proposed or continuing drill sites across the country.


What Fracking Involves

The method for extracting methane gas being used in the Marcellus Shale region of the U.S. is more formally called "horizontal hydraulic fracturing," or hydrofracking or fracking. In this process, a fluid is injected into the rock which then releases the gas along with radioactive toxins and other hazardous substances in the shale. This procedure has raised serious environmental and health concerns.[6] In New Mexico, for example, similar processes have leached toxic chemicals into the water table at 800 sites.[7] To force methane gas out of shale, millions of gallons of fresh, drinkable water are forced through a pipe drilled into the shale at extremely high pressure. A variety of chemicals are added to the water to keep the fractures in the shale open and keep the gas flowing to the surface.

Pro Publica has created two very helpful charts depicting how the fracking process works. "What is Hydraulic Fracturing?" can be seen at: http://www.propublica.org/special/hydraulic-fracturing-national and "Anatomy of a Gas Well can be seen at: http://www.propublica.org/feature/anatomy-of-a-gas-well-426.

Hydrofracking and the "Halliburton Loophole"

In 2005, at the urging of Vice President Dick Cheney, Congress created the so-called "Halliburton loophole" to clean water protections in federal law to prevent the U.S. Environmental Protection Agency from regulating this process, despite serious concerns that were raised about the chemicals used in the process and its demonstrated spoiling and contamination of drinking water. In 2001, Cheney's "energy task force" had touted the benefits of hydrofracking, while redacting references to human health hazards associated with hydrofracking. Halliburton, which was previously led by Cheney, reportedly earns $1.5 billion a year from its energy operations, which rely substantially on its hydrofracking business.)[8]

According to Pro Publica reporter Abrahm Lustgarten, the EPA under Christine Todd Whitman's tenure as Administrator engaged in secret negotiations with industry, while purportedly addressing drinking water issues related to "fracking."[9] In 2004, the EPA undertook a study on the issue and "the EPA, despite its scientific judgment that there was a potential risk to groundwater supplies, which their report clearly says, then went ahead and very surprisingly concluded that there was no risk to groundwater," Lustgarten noted in September 2009. "[P]art of my reporting found that throughout that process the EPA was closer than seemed comfortable with the industry. I filed FOIA requests for some documents and found conversations between Halliburton employees and the EPA researchers, essentially asking for an agreement from Halliburton in exchange for more lax enforcement. The EPA, in these documents, appeared to offer that and agree to that. And it doesn’t appear, by any means, to have been either a thorough or a very objective study." [10]

In June 2009, U.S. Representatives Diana DeGette, John Salazar and Maurice Hinchey and Senators Robert P. Casey Jr. and Chuck Schumer introduced the Fracking Responsibility and Awareness of Chemicals Act (FRAC ACT).[11] The proposal is aimed at closing the 'Halliburton loophole' and requiring the oil and gas industry to disclose the chemicals used in drilling projects which can contaminate ground water and drinking water.

In late October 2009 the House of Representatives agreed to include a statement in the Interior and Environment Appropriations bill and report for fiscal year 2010 urging the EPA to reassess the impact of fracking on water supplies. The report stated:
"The conferees urge the EPA to carry out a study on the relationship between hydraulic fracturing and drinking water, using a credible approach that relies on the best available science, as well as independent sources of information. The conferees expect the study to be conducted through a transparent, peer-reviewed process that will ensure the validity and accuracy of the data. EPA shall consult with other federal agencies as well as appropriate state and interstate regulatory agencies in carrying out the study, and it should be prepared in accordance with EPA quality assurance principles."[12]
On March 18, 2010, the Environmental Protection Agency announced that it would lead a $1.9 million for this comprehensive, peer-reviewed study on the impacts hydrofracking would have on water quality and public health.[13] Despite the study, Rep. Diana DeGette (D-CO) has expressed that it is crucial to continue the push forward for the passing of the FRAC Act[14]
More information about other legislative proposals can be found in the main page on this topic, Marcellus Shale.

Possible violations of the Safe Drinking Water Act

Although the 2005 Bush-Cheney Energy Policy Act exempted hydraulic fracturing from the Safe Drinking Water Act - the "Halliburton Loophole" - it made one small exception: diesel fuel. The Policy Act states that the term “underground injection,” as it relates to the Safe Drinking Water Act, “excludes the underground injection of fluids or propping agents (other than diesel) pursuant to hydraulic fracturing operations related to oil, gas, or geothermal production activities [italics added].” But a congressional investigation has found that oil and gas service companies used tens of millions of gallons of diesel fuel in fracking operations between 2005 and 2009, thus violating the Safe Drinking Water Act. Diesel fuel contains a number of toxic constituents including benzene, toluene, ethylbenzene, and xylene, which have been linked to cancer and other health problems.[15]

In a letter to EPA Administrator Lisa Jackson, the congressional committee noted that between 2005 and 2009, “oil and gas service companies injected 32.2 million gallons of diesel fuel or hydraulic fracturing fluids containing diesel fuel in wells in 19 states.” None of the companies sought or received permits to do so. “This appears to be a violation of the Safe Drinking Water Act. It also means that the companies injecting diesel fuel have not performed the environmental reviews required by the law.” Yet because the necessary environmental reviews were circumvented, the companies were unable to provide data on whether they had used diesel in fracking operations in or near underground sources of drinking water.[15]

The EPA is conducting its own study of the impact of hydraulic fracturing on drinking water supplies, due out in late 2012. It is unknown whether companies that have violated the Safe Drinking Water Act since 2005 be held accountable. Matt Armstrong, a lawyer with the Washington firm Bracewell & Giuliani, which represents several oil and gas companies, told the New York Times: “Everyone understands that E.P.A. is at least interested in regulating fracking.” But: “Whether the E.P.A. has the chutzpah to try to impose retroactive liability for use of diesel in fracking, well, everyone is in a wait-and-see mode. I suspect it will have a significant fight on its hands if it tried it do that.”[15]

Why People Are Concerned

Although no complete list of the cocktail of chemicals used in this process exists, information obtained from environmental clean-up sites demonstrates that known toxins are routinely being used, including hydrochloric acid, diesel fuel (which contains benzene, tuolene, and xylene) as well as formaldehyde, polyacrylimides, arsenic, and chromates.[16] In a letter to Congress, an Environmental Protection Agency employee describes how the Bush Administration's EPA produced a scientifically unsupportable conclusion that hydrofracking should not be regulated under the Clean Water Drinking Act.[17] These chemicals include known carcinogens and other hazardous substances.[18]

Pro Publica reporter Abrahm Lustgarten revealed that as much as 85% of the fluids used during hydrofracking is regularly left underground after wells are drilled in the Marcellus Shale. Translation: "[Over] three million gallons of chemically tainted wastewater could be left in the ground forever. Drilling companies say that chemical make up less than 1% of that fluid...[which] still amount[s] to 34,000 gallons in a typical well." The old school of thought was that only roughly 30% of the fluids stayed in the ground, which has proven false.[19] Toxics Targeting created a video which shows what they call "ignitible water."[20] The video can be seen at right.

Fracking and Ignitible Water

Concerns about Fracking and the New York City Water Supply

Citizen groups have mobilized in New York to oppose hydrofracking. This opposition has deployed several tactics, including a class action lawsuit.[21] New videos have also been produced to educate the public about the dangers of fracking the Marcellus shale. In the following video, Manhattan Borough President Scott Stringer calls massive proposed drilling operations in the watershed that provides New York City with its drinking water is the "most alarming environmental news he has heard in a long time, and makes this the number one environmental crisis" they face in the city:

Kill the Drill
In response to these and other concerns, New York City urged the state to ban methane gas drilling in its watershed on Wednesday, December, 23, 2009. Steven Lawitts, the city's top environmental official, called fracking techniques "unacceptable threats to the unfiltered fresh water supply of nine million New Yorkers," putting the City at odds with the methane gas industry, which considers shale drilling completely safe. Marc LaVorgna, spokesman for NYC Mayor Michael Bloomberg stated, "Based on all the facts, the risks are too great and drilling simply cannot be permitted in the watershed."[22]
The New York Times noted that the New York State Department of Environmental Conservation, which was tasked with "going through a public review of its new rules on hydraulic fracturing," was looking into reports that "gas companies use at least 260 types of chemicals, many of them toxic, like benzene. These chemicals tend to remain in the ground once the fracturing has been completed, raising fears about long-term contamination."[23]
American Rivers, a Washington, D.C. advocacy group, announced on June 3, 2010, that hydrofracking poses a huge threat to the Delaware River, which is the drinking source for nearly 17 million people across New York, New Jersey, and Pennsylvania. In the America's Most Endangered Rivers Report: 2010 Edition report, the American Rivers advocacy group named the Delaware River the number one most at-risk river, due to the threat of extensive drilling into the Marcellus Shale.[24] Here is a great link to a Factsheet produced by the American Rivers Group on the threat faced to the Delaware River by drilling into the Marcellus Shale: http://www.americanrivers.org/assets/pdfs/mer-2010/upperdelaware_factsheet_2010.pdf

Facts about Drilling

Dangers of Fracking Noted around the Country

Catskill Mountainkeeper has noted that "A number of these [hydrofracking] fluids qualify as hazardous materials and carcinogens, and are toxic enough to contaminate groundwater resources. There are cases in the U.S. where hydraulic fracturing is the suspected source of impaired or polluted drinking water. In Alabama, Colorado, New Mexico, Virginia, West Virginia and Wyoming, incidents have been recorded by people who have gas wells near their homes. They have reported changes in water quality or quantity following fracturing operations." [25] Significant harms have also been exposed in Pennsylvania, as noted below.


On November 9, 2009, Reuters reported that the owner of 480 acres of land in southwest Pennsylvania claimed Atlas Energy Inc. ruined his land with toxic chemicals used in or released there by hydraulic fracturing, and he also claimed to find seven potentially carcinogenic chemicals above permissible levels set by the U.S. Environmental Protection Agency. He performed tests on his well water a year before drilling began and said the water conditions were "perfect." After the drilling began, water tests found arsenic at 2,600 times acceptable levels, benzene at 44 times above limits and naphthalene five times the federal standard. He has decided to sue Atlas Energy Inc. for negligence and is seeking an injunction against further drilling, and unspecified financial damages. Jay Hammond, general counsel for Atlas, said Zimmermann's claims are "completely erroneous" and said Atlas will "vigorously" defend itself in court and declined further comment.[26]

Later that month on November 20, 2009, Reuters reported that residents of Dimock sued Cabot Oil & Gas Corp claiming the company's natural-gas drilling had contaminated their water wells with toxic chemicals, caused sickness and reduced their property values. The complaint says residents have suffered neurological, gastrointestinal and dermatological symptoms from exposure to tainted water. They also say they have had blood test results consistent with exposure to heavy metals. The lawsuit accuses Cabot of negligence and says it has failed to restore residential water supplies disrupted by gas drilling.[27] Contaminated water from methane gas drilling operations, such as in Dimock, Pennsylvania, is often ten times more toxic than water produced from petroleum production, and can contain high concentrations of salts, acids, benzene, toluene, ethylbenzene, xylene, radioactive materials," and other chemicals. [28]


Oil and gas drilling in Colorado, predominantly in western Colorado, has raised health concerns from residents who believe the industry is the root cause of their illnesses or that is has exacerbated disease.

Chris Mobaldi, who lived in Rifle, Colorado, believes her neurological system was damaged by drinking water that may have been contaminated by drilling fluids from wells around her home. She had two tumors removed from her pituitary gland and endured excruciating pain. [29]

Odor complaints and air pollution concerns are also on the rise in Garfield County, on the western slope, where longtime residents often endure hazy skies in the Colorado River valley. Many believe the gas industry is responsible. Carol and Orlyn Bell noticed a "terrible" smell when they neared their Dry Hollow ranch, south of Silt, Colorado. "It was the strongest odor we've smelled in the last four years," Carol Bell said. The Bells said the odor came from nearby gas wells and production facilities, something they've seen surround their 110-acre ranch within the span of four years. [30]

From September to December, 2005, the Colorado Oil and Gas Commission documented ten complaints from eight separate households related to odors emanating from wells being drilled and completed by the Barrett Corporation [31]


In the April 30, 2009 [Pro Publica]]'s Abrahm Lustgarten wrote about a story he dug up from Louisiana's Shreveport Times. The story revealed that 16 cattle mysteriously and abruptly dropped dead in a "northwestern Louisiana field after apparently drinking from a mysterious fluid adjacent to a natural gas drilling rig, according to Louisiana's Department of Environmental Quality. At least one worker told the newspaper that the fluids . . . were used for . . . hydraulic fracturing.[32]


In late 2007, three families near Grandview, Texas noticed changes in their well water just after a natural gas well within a couple of hundred yards of their properties was hydraulically fractured. Within days, five goats and a llama had died. All three families noticed strong sulfur smells in their water, making it unusable. At first their water ran dry, and then the water returned with extremely high pressure, blowing out pipes. Showering caused skin irritation. The Railroad Commission of Texas acknowledged that testing of well water found toluene and other toxic contaminants.[33]


Reuters also reports that "the U.S. Environmental Protection Agency found 14 "contaminants of concern" in 11 private wells in the central Wyoming farming community of Pavillion, an area with about 250 gas wells.[34]

Documentary Film Gasland Exposes the Harms Caused by Hydrofracking

Gasland Trailer
Gasland is a 2010 documentary about unconventional natural gas drilling, or hydraulic fracturing. Its director, Josh Fox, lives in the Upper Delaware River Basin, on the border between Pennsylvania and New York State, part of the area of Marcellus Shale. (For more information on Gasland, Marcellus Shale, and the impact of drilling on drinking water, please see SourceWatch's water clearinghouse.)
In May 2008, Fox received a letter from a natural gas mining company, who wanted to lease 19.5 acres of land from Fox for $100,000. On an interview on NPR's Fresh Air, Fox said the company stated,"'We might not even drill. We don't even know if there's gas here. It's going to be a fire hydrant in the middle of a field — very little impact to your land. You won't hardly know we're here.' " Instead of saying yes, Fox decided to travel around the country to see how the process of natural gas drilling affected other communities and homeowners, producing the documentary Gasland.[35]

In an interview on NPR's Fresh Air, Fox talked about the effects of unconventional gas drilling, and lack of regulations on hydraulic fracturing, also known as "Fracking": "Hydraulic fracturing is a process of injecting, at incredibly high pressure, a huge volume of water — they use between 2 and 7 million gallons of water per frack to fracture the rock formation. It's called unconventional gas drilling. It fractures that rock apart and gets at all of the tiny bubbles of the gas that are sort of infused in that rock. In order to do that, they inject [these] million gallons of fluid down the wellbore that breaks apart the rock. It causes a kind of mini-earthquake under very intense pressure. What seems to be happening is that's liberating gas and other volatile, organic compounds. ... The volatile organics are released along with the gas. Sometimes they're used as part of the compounds. The fracking fluid creates this. You're releasing volatile organics, which are carcinogenic, and that is traveling, somehow — along with the methane — getting into peoples' water supply so that it's flammable."[35

Some homeowners he spoke to noticed that their water had been discolored, or was starting to bubble. In some communities, people were able to light the water coming out of their faucets on fire — because chemicals from the natural gas drilling process had seeped into the water, an event documented in the film. Despite the pollutants, Fox says, "[t]he gas industry is very powerful, and their power in Congress is well shown. They were exempted from the Safe Drinking Water Act by the 2005 Energy bill. The Safe Drinking Water Act monitors underground injection of toxins. They were also exempted in previous years from the Clean Air Act, the Superfund Law. . . . It's an unregulated industry."[35]

At the end of the interview, Fox summed up the extent of the reach of the gas industry into community water supplies:[35]

Josh Fox: "You'd be surprised at how many of those summer camps are leasing [their land to natural gas companies]. Listen, we're talking about 65 percent of Pennsylvania, 50 percent of New York. Even if the summer camps aren't leased, their neighbors are leasing."
Terry Gross: "You know, I never thought of that. So that means some of the summer camps might become oil wells?"

Josh Fox: "Well, no. Listen. What the gas company is saying is, 'You can live where this is happening. You can go to camp where this is happening.' If watersheds are not off the table, schools are not off the table, summer camps are not off the table — near hospitals are not off the table. You have close to 15,000 wells in the downtown Fort Worth area — in the urban area, in the country, in the city. This is everywhere. So it stands to reason if you can put it next to somebody's house and the gas company says that's OK, you can put it in the middle of a summer camp. You can put it in the middle of a lake. You can put it right on the banks of the Colorado River, which supplies all the water to Los Angeles. This is what we're seeing."

Enforcement Problems

With state budget limitations and shortfalls, oil and gas regulators are spread too thin to do their jobs, even with the minimal guidelines in place[36] In West Virginia, for example, for the state's 17 inspectors to visit West Virginia's 55,222 wells once a year, they would have to inspect nine wells a day, every day of the year, with no weekends off, nor any vacation days. While the number of new oil and gas wells being drilled in the 22 states each year has jumped 45 percent since 2004, most states have added only a few regulators.[37]

Texas has largest imbalance, with 273,660 wells and just 106 regulators to oversee them. In late 2007, a Texas state auditor's report found that nearly half of the state's wells hadn't been inspected in the five years between 2001 and 2006, when the data was collected. According to Pro Publica's analysis, the number of new wells drilled each year in Texas has jumped 75 percent since 2003. However, staffing increased just 5 percent during that period and enforcement actions increased only 6 percent.[38]

Maps and charts depicting this problem can be seen here: http://projects.propublica.org/gas-drilling-regulatory-staffing/

Articles and resources

External resources

Split Estate Trailer

  • Information from the Union of Concerned Scientists:
"When an EPA study concluding that hydraulic fracturing "poses little or no threat" to drinking water supplies was published in 2004, several EPA scientists challenged the study's methodology and questioned the impartiality of the expert panel that reviewed its findings. The Bush administration has strongly supported hydraulic fracturing, an oil extraction technique developed by Halliburton Co., but environmental groups as well as scientists within the EPA have warned that the practice may contaminate drinking water and needs to be regulated."[39]
  • For information from Earthworks on the environmental impact of fracking on U.S. residents and efforts to close the Halliburton loophole, see http://www.earthworksaction.org/pubs/JointFS_HalliburtonLoophole.pdf.
  • Toxics Targeting also has more information on fracking in New York state. They are a service that obtains environmental data from local, state and federal government sources and interactively maps toxic sites on a lot-by-lot basis in New York, has identified 270 past oil and gas spills in New York state that have caused fires, explosions, home evacuations, massive pollution releases, contaminated drinking water sources and tainted farmland. For more information on how they are helping citizens get more involved, see http://www.toxicstargeting.com/MarcellusShale/coalition_letter sign a letter


  1. Jeff Moscou A Toxic Spew? Officials worry about impact of 'fracking' of oil and gas Newsweek August 20, 2008
  2. Catskill Mountainkeeper, "Marcellus Shale: The Marcellus Shale – America's next super giant", Catskill Mountainkeeper website, accessed March 2009.
  3. "What Is Hydraulic Fracturing?", Pro Publica, accessed October 2009.
  4. Abrahm Lustgarten, "New York’s Gas Rush Poses Environmental Threat", Pro Publica, July 22, 2008.
  5. See Jeff Moscou A Toxic Spew? Officials worry about impact of fracking of oil and gas Newsweek August 20, 2008
  6. "What Is Hydraulic Fracturing?", Pro Publica, undated, accessed October 2009.
  7. Abrahm Lustgarten, "New York’s Gas Rush Poses Environmental Threat", Pro Publica, July 22, 2008.
  8. Tom Hamburger and Allen C. Miller, "Halliburton's Interests Assisted by the White House", Los Angeles Times, October 14, 2004.
  9. See http://www.democracynow.org/2009/9/3/fracking_and_the_environment_natural_gas.
  10. Interview with Abrahm Lustgarten, "Fracking and the Environment: Natural Gas Drilling, Hydraulic Fracturing and Water Contamination," Democracy Now!, September 3, 2009.
  11. "Senators, Representatives act to close Halliburton Loophole in the Safe Drinking Water Act", Media Release, June 9, 2009.
  12. Congressman Maurice Hinchey, "Congress Gives Final Approval to Hinchey Provision Urging EPA to Conduct New Study on Risks Hydraulic Fracturing Poses to Drinking Water Supplies", Media Release, October 29, 2009.
  13. [1], "EPA Initiates Hydraulic Fracturing Study: Agency seeks input from Science Advisory Board." Environmental Protection Agency, March 18, 2010.
  14. [2], "EPA to study hydraulic fracturing, but calls for FRAC Act continue." Colorado Independent. March 18, 2010.
  15. 15.0 15.1 15.2 Adam Federman, "Oil and Gas Companies Illegally Using Diesel in Fracking" AlterNet, Feb. 1, 2011.
  16. [3] "Q+A: Environmental fears over U.S. shale gas drilling," Reuters, Dec. 23, 2009.
  17. Weston Wilson, Letter to Senators Allard and Campbell and Representative DeGette, October 8, 2004.
  18. "Gas Drilling Plan Raises Water Contamination Fears in New York City", Voice of America News, Carolyn Weaver, December 24, 2009
  19. [4], "New gas wells leave more chemicals in ground," Abrahm Lustgarten, Politico.com, December 27, 2009
  20. [5], "Ignitible Drinking Water From a Well in Candor, New York, Located Above the Marcellus Shale Formation."
  21. "Marcellus Shale Developments", Pocahantas County Fare Blog, March 9, 2009
  22. "NYC urges ban on shale gas drilling in watershed", Edith Honan, "Reuters" December 23, 2009].
  23. [6] "Dark Side of a Natural Gas Boom," Jad Mouawad and Clifford Krauss, New York Times, Dec. 8, 2009
  24. [7],"America's Most Endangered Rivers Report: 2010 Edition: #1 Upper Delaware River, Pennsylvania and New York Threat: Natural Gas Extraction."
  25. "The Marcellus Shale – America's next super giant" Catskill Mountainkeeper", 2009
  26. [8] "Pennsylvania lawsuit says drilling polluted water," Jon Huddle, Reuters, Nov. 9, 2009.
  27. [9] "Pennsylvania residents sue over gas drilling," Jon Huddle, Reuters, Nov. 20, 2009.
  28. [10], "What the Frack? Poisoning our Water in the Name of Energy Profits," Peter Gleick, Pacific Institute, December 8, 2009
  29. Judith Kohler (The Associated Press) 'Collateral damage' - Residents fear murky effects of energy boom, Aspen Times, December 3, 2006
  30. Associated Press Oil and Gas Drilling Raise Health Concerns in Garfield County, Summit Daily News, October 22, 2006
  31. Eaerthworks Action Contamination Incidents Related to Oil and Gas Development, Web page, accessed February 3, 2010
  32. [11], "16 Cattle Drop Dead Near Mysterious Fluid at Gas Drilling Site," Abrahm Lustgarten, ProPublica, April 30, 2009
  33. "Congress Should Close the Halliburton Loophole Hydraulic fracturing should be regulated under the Safe Drinking Water Act", EarthsWorkAction.org
  34. [12] "Q+A: Environmental fears over U.S. shale gas drilling," Reuters, Dec. 23, 2009.
  35. 35.0 35.1 35.2 35.3 "Josh Fox: Living In The Middle Of A 'Gasland'" NPR, June 25, 2010.
  36. "State Oil and Gas Regulators Are Spread Too Thin to Do Their Jobs", Abrahm Lustgarten, Pro Publica; December 30, 2009
  37. "State Oil and Gas Regulators Are Spread Too Thin to Do Their Jobs", Abrahm Lustgarten, Pro Publica; December 30, 2009
  38. [13], Abrahm Lustgarten, Pro Publica, December 30, 2009
  39. Union of Concerned Scientists, "EPA Findings on Hydraulic Fracturing Deemed 'Unsupportable'", Union of Concerned Scientists website, undated, accessed October 2009.

External Resources

External Articles

Source: http://www.sourcewatch.org/index.php?title=Fracking#Colorado