This article is an excerpt from Richard Heinberg’s new book SNAKE OIL: How Fracking’s False Promise of Plenty Imperils Our Future. Given the urgency and importance of the issues we are serializing the book here at Resilience.org.
News item, dateline February 14, 2013: Ben Lupo, 62, owner of Hardrock Excavating in Poland, Ohio, was charged with violating the Federal Clean Water Act by ordering an employee to dump thousands of gallons of brine and fracking waste discharge into a tributary of the Mahoning River. Lupo faces up to three years in prison, a $250,000 fine, and a year of supervised release if convicted. He has pleaded innocent.
Fracking opponents in Ohio seized upon the Lupo incident to call for a ban or moratorium on drilling. Fracking supporters insisted this was merely an isolated case; further, they said, the fact Lupo was caught and prosecuted simply showed that existing regulations were sufficient and effective.
It would be reassuring to know the Lupo incident did indeed represent a unique or rare occurrence, and that fracking is otherwise as safe as a walk in the park. The oil and gas industry, after all, claims to be making serious attempts to address environmental problems as they arise—finding better ways to dispose of or recycle wastewater, building better well casings, and exploring methods of capturing fugitive methane.
But fracking by its very nature implies a wide range of environmental risks, of which failure to properly treat wastewater is only one. Remember: as society extracts fuels from lower and lower levels of the resource pyramid, it must use ever more extreme measures, and more things can go wrong. Further, as we have just seen, the high per-well decline rates associated with shale gas and tight oil wells mean that drillers must frack relentlessly in order to maintain production rates; therefore environmental risks are multiplied thousands, tens of thousands, and ultimately hundreds of thousands of times over.
Across America, hundreds of grassroots groups with names like New Yorkers Against Fracking, Save Colorado from Fracking, Blackfeet Anti-Fracking Coalition, No Frackin’ PA!, Don’t Frack Ohio, and Ban Michigan Fracking have sprung up and formed mutual support networks. Many of the people who start or join such groups had never previously thought of themselves as environmentalists but are compelled to action by methane in drinking water, sickened livestock, bad air quality, or constant truck noise.
In response, the industry has mounted a public relations offensive. The pro-fracking website energyfromshale.org insists, for example, that “hydraulic fracturing technology has a strong environmental track record” and that “properly designed and constructed oil and natural gas wells present low environmental risk to our groundwater.”
Why has there been such a massive grassroots backlash against fracking? In this chapter, we’ll look at the evidence for fracking’s impacts on water, air, land, and climate. Reader warning: it ain’t pretty.
Everyone agrees that fracking takes water—lots of it. A single well-pad cluster might require more than 60 million gallons. Where does all this water come from? Sometimes drillers buy water from wells on leased property, sometimes they pump it from nearby streams or rivers, sometimes they purchase it from municipal water systems. In the dry states of the American southwest, future drilling could draw water from the Colorado River at a rate equivalent to that of an additional large city, yet the region already faces the prospect of serious water shortages.1 As climate change results in more widespread and severe drought conditions, finding water for shale gas and tight oil production is likely to pose an ever more vexing conundrum. One arid county in New Mexico has already banned fracking due to its fierce water needs.2
That’s only the start of fracking’s water problems. After water has been injected deep underground in the hydrofracturing process, most of it is pumped back to the surface. At that point, the water carries with it not only a secret cocktail of chemicals added so that it can accomplish its mission, but also highly corrosive salts, carcinogenic benzene, and radioactive elements like cesium and uranium, all leached from rock strata miles underground.3
What’s a fracker to do with all this toxic wastewater? There are several options. Drillers can inject it into deep wells—either older abandoned oil or gas wells, or holes newly drilled for the purpose. Wastewater can also be held in large evaporation pools or sent to municipal treatment facilities. Each of these options is problematic. Underground injection simply means taking precious freshwater out of aquifers or rivers, polluting it, and then burying it so that it can never be used again. Evaporation pools poison birds and are prone to leaks and spills. Municipal water treatment plants are poorly equipped to remove the pollutants in fracking wastewater, especially when many of those pollutants are company secrets. An additional problem for wastewater treatment plants is the radioactivity released in fracking: reports from the US Environmental Protection Agency (EPA) made public in 2011 showed that fracking wastewater is too radioactive to be dealt with safely by municipal treatment plants, raising the specter of entire cities drinking radioactive water so that residents can continue burning natural gas.4
Increasingly, fracking operations recycle most of their water, using wastewater from one well in the next well’s initial hydrofracturing. This helps with the problems of sourcing water for operations and disposing of waste, but it is far from a complete solution. While the industry says it is aiming for 100% recycling, that goal is probably unattainable for purely practical reasons; currently, recycling efforts achieve about 50% efficiency. New sources of water are still needed, and toxic effluents have a way of leaking and seeping.
In October 2011, the EPA announced plans to develop standards for disposing of fracking wastewater; as of this writing, those standards have yet to be issued.
Fracking wastewater can make its way into streams and rivers, impacting both municipal water supplies and wildlife. A study published in the Proceedings of the National Academy of Sciences documents how chloride from fracking wastewater ends up in Pennsylvania’s rivers and streams, even when the wastewater has been treated at municipal facilities.5 The same study also found that waterways are impacted by increased amounts of total suspended solids (TSS) from shale gas drilling. High TSS levels decrease the amount of dissolved oxygen in streams, raise water temperatures, and block sunlight. The study found that 18 well pads in a water-shed increases TSS concentrations by 5%. For perspective, consider that 4,000 well pads have been constructed in Pennsylvania since the beginning of the fracking boom.6
Shale gas drilling also runs the risk of contaminating water tables. Drillers guard against this by isolating water tables from wells with cemented-steel well casings. However, well casings sometimes fail. The industry claims that casings fail less than 1% of the time, yet independent research suggests the failure frequency may be much higher, perhaps in the range of 6–7%.7
Eventually (speaking now in terms of centuries and millennia) all well casings will leak. When a well reaches the end of its useful life, operators install cement plugs in the borehole to prevent migration of fluids between the different rock layers. This may render the well safe for decades to come, but seismic activity can dislodge even the most carefully placed plugs. According to a paper by Maurice B. Dusseault, Malcolm Gray, and Pawel A. Nawrocki, published by the Society of Petroleum Engineers in 2000, “Oil and gas wells can develop gas leaks along the casing years after production has ceased and the well has been plugged and abandoned.”8 The most frequent reason for such failures is probably cement shrinkage, leading to fractures that are propagated upward by the slow accumulation of gas under pressure behind the casing.
Once again, the high rates of drilling required in order to maintain overall field production rates in shale gas and tight oil plays serve to amplify risk: even if just 1% of well casings fail, for the more than 65,000 current wells in fracking country that translates to 650 instances of likely contamination. If failure rates are 6%, that raises the number to 3,900. Actual instances of water table pollution resulting from well casing problems are documented, despite industry efforts to deny, distract, and evade: for example, in 2007 the faulty cement seal of a fracked well in Bainbridge, Ohio, allowed gas from a shale layer to leak into an underground drinking water source; the methane built up until it caused an explosion in a homeowner’s basement.9 Other such tales would likely be more commonly heard were it not for the industry’s insistence on nondisclosure agreements when landowners whose water has been contaminated settle lawsuits with drillers.
Anecdotes about flammable tap water or dying house pets can be emotionally compelling, but at the end of the day, decisions about whether to allow or ban fracking must be based on scientific studies and statistical analyses addressing the question of whether and to what degree drilling actually impacts the water we drink. Such studies have been slow to appear, partly because of industry efforts to withhold or suppress information. Nevertheless, according to one report, published in 2011 in the Proceedings of the National Academy of Sciences, drinking water samples from 68 wells in the Marcellus and Utica shale plays were contaminated with excess methane.10 The study found that average methane concentrations in wells near active fracturing operations were 17 times higher than in wells in inactive areas. Methane concentrations varied according to proximity to the drilling sites. Subsequent tests confirmed the findings.11
While more research is needed, initial findings suggest that fracking and water safety just don’t mix.
Methane, the primary constituent of natural gas, is colorless, odorless, and nontoxic—though in significant concentrations it is highly explosive. When methane is inadvertently released in gas or oil drilling, it reacts with atmospheric hydroxyl radicals (OH) to produce water to produce water vapor and carbon dioxide, which are likewise nontoxic. (We’ll discuss the climate impacts of methane and carbon dioxide later in this chapter; for now we are concerned only with toxic air pollution.)
However, other chemicals often present in natural gas at the wellhead—including hydrogen sulfide, ethane, propane, butane, pentane, benzene, and other hydrocarbons—can degrade air quality significantly. In addition, emissions from trucks, compressors, pumps, and other equipment used in drilling contain a complex mixture of benzene, toluene, and xylene, as well as other volatile organic compounds. Drilling activity and truck traffic create high levels of dust, while flaring of methane also contributes to air pollution. Some chemicals associated with drilling combine with nitrogen oxides to form ground-level ozone. It is often difficult to trace the exact causal connections between oil and gas drilling, air pollution, and human health impacts; however, people who work at or live near fracking sites have complained of a wide variety of new illnesses with symptoms including skin rashes, open sores, nosebleeds, stomach cramps, loss of smell, swollen and itching eyes, despondency, and depression.12
Ozone pollution is normally associated with automobile exhaust, but fracking also generates it when the volatile organic compounds in wastewater ponds evaporate and come in contact with diesel exhaust from trucks and generators at the well site. Ozone inflames lung tissues and can cause coughing, chest pains, and asthma. Human health is harmed both by prolonged exposure to low-level ozone concentrations and by exposure to higher levels for shorter durations. Children and the elderly are the most susceptible.13
Tight oil production in North Dakota releases lots of associated methane—but, given a lack of pipeline infrastructure, drillers usually just burn the methane on-site rather than attempting to capture it. Nighttime satel-lite photos of the state show light from natural gas flares rivaling the city lights of Chicago and other major metropolitan areas. Flaring can result in the emission of a host of air pollutants, depending on the chemical composition of the gas and the temperature of the flare. Emissions from flaring may include hydrogen sulfide, benzene, formaldehyde, polycyclic aromatic hydrocarbons (such as naphthalene), acetaldehyde, acrolein, pro-pylene, toluene, xylenes, ethyl benzene, and hexane. Canadian researchers have measured more than 60 air pollutants downwind of natural gas flares.14
Once again, anecdotes are easy to come by (such as the story of Joyce Mitchell of Hickory, Pennsylvania, who leased drilling rights on her land to Range Resources only to endure a constant barrage of noxious fumes),15 but also easy to brush off as isolated incidents that don’t reflect the actual safety record of the industry. Scientific studies and statistical analyses are crucial but have been slow to appear.
A recent article in the journal Environmental Science and Technology concluded, on the basis of data from National Oceanic and Atmospheric Administration (NOAA), that oil and gas activity in the Wattenberg field in the Niobrara formation in Colorado “contributed about 55% of the volatile organic compounds linked to unhealthy ground-level ozone” in the area. NOAA maintains an air-monitoring tower outside the small town of Erie, Colorado, located in the Niobrara play, and found that this town of 18,000 now has methane and butane spikes that exceed by four to nine times the levels of those pollutants in Dallas, Texas, a city with some of the worst air in America.16
A study by The Endocrine Disruption Exchange, led by environmental health analyst Dr. Theo Colborn, measured more than 44 hazardous pollutants at operating well sites in Garfield County, Colorado. The study detected pollutants up to seven-tenths of a mile from the well site. Many of the chemicals detected are known to impact the brain and nervous system; some are known hormonal system disruptors. The human endocrine system is so sensitive that even tiny doses of some of these chemicals, measured in parts per billion, can lead to large health effects.17
As gas drilling expands throughout the nation, production is moving closer to populated areas, with wells in some states now being drilled within a few hundred feet of schools and homes.
Expect bad air.
Suppose you own farmland, and you also own the subsurface mineral rights to your land.18 A petroleum company offers you money for the right to drill on your property. Drillers promise to rehabilitate the acreage when they’re done. You need the money. What should you do?
Your answer may depend on how badly you need the money. But it will also reflect your philosophy—whether you see the land merely as a speculative investment, or whether you have a sense of obligation to its welfare. That’s because drilling for shale gas or tight oil can seriously impact land—whether through water, air, or soil pollution; damage to vegetation, livestock, and wildlife; or erosion and induced earthquakes.
Heavy metals such as lead, mercury, cadmium, chromium, barium, and arsenic have been found in soils near natural gas drilling sites. And when fracking leads to increased ground-level ozone, plants are damaged by inhibited photosynthesis and root development.19
Livestock and wildlife, attracted by the salty taste of fracking fluids and wastewater, can be poisoned—either dying outright or suffering loss of reproductive function, stillbirths, birth defects, and other maladies.20 Light and noise from fracking and related traffic can also increase animal stress. A peer-reviewed study in 2012 by professor of molecular medicine Robert Oswald and veterinarian Michelle Bamberger found significant adverse health links between fracking and livestock exposed to the air and water by-products of drilling. Animals were found to suffer neurological, reproductive, and gastrointestinal disabilities.21
Colorado Division of Wildlife officials have observed both indirect effects leading to population declines and direct mortality in wildlife, in areas of intensive natural gas drilling. Waterfowl are most directly impacted, as they can land in wastewater pits near drilling pads. Industrial activity too near an area where a raptor pair is engaged in courtship behavior may discourage mating, and stress can cause the adult birds to abandon eggs or even young; the loss of a breeding season reduces population over time. Deer and elk populations decline when areas of unbroken habitat are reduced by land fragmentation from road building and well pad construction. Wild fish populations are threatened by spills of industrial materials or toxic chemicals.22
In mountainous regions of the Marcellus shale formation, drilling leads to erosion. Loosened sediments quickly enter surface streams, contaminating coldwater fish habitats and drinking water sources.23
Most earthquakes triggered by hydraulic fracturing are too weak to be felt or cause significant damage—though the number of quakes in normally seismically quiet parts of fracking country in Arkansas, Texas, Ohio, and Colorado is on the rise. Indeed, according to a USGS study, in the last four years the number of quakes in the middle of the United States jumped elevenfold from the previous three decades. The largest yet measured, in central Oklahoma on November 6, 2011, was a magnitude 5.7 temblor tied to the injection of fracking wastewater. It was the biggest quake ever recorded in Oklahoma, destroying 14 homes, buckling a highway, and leaving two people injured.24 Earthquakes are an especially serious issue in California, a state riddled with seismic faults, yet also contemplating whether to allow drillers to increasingly exploit the Monterey shale formation.
The various forms of land damage from fracking often result in decreased property values, making resale and farming difficult, and also making it harder to acquire mortgages and insurance. Properties adjoining drilling sites are often simply unsellable, as no one wants to live with the noise, the bad air, and the possibility of water pollution.25
All of these problems are once again multiplied by fracking’s need for heroic rates of drilling, and therefore for enormous numbers of drilling sites. Consider just the state of Colorado: at the start of 2012 approximately nine thousand square miles of public land in Colorado had been leased to the oil and gas industry for drilling—roughly 10% of the state. The amount of private land under lease is probably greater, though exact figures are harder to come by. Thus, it is likely that roughly a fifth of the land area of Colorado is currently leased by the oil and gas industry.
Finally, fracking can affect land far away from drilling sites. Sand is being mined in Wisconsin, Minnesota, and Iowa for fracking in Pennsylvania, Texas, and North Dakota. The round, fine-grained sand in these regions, left over from the grinding of glacier upon rock during the last Ice Age, is ideal for use as a fracking proppant, but mining operations destroy farmland, impact wildlife, and degrade streams.26Moreover, when winds take up the tiny silica particles dislodged by mining, higher rates of silicosis and cancer result.27
Considering emissions only at the point of combustion, current US natural gas power plants produce 56% less carbon dioxide, per kilowatt-hour, than existing coal plants.28 Therefore, as the world gradually transitions toward renewable energy sources, it might seem prudent to replace coal-burning power plants with natural gas burners as a stopgap measure. That way, natural gas could serve as a bridge fuel to reduce carbon emissions while society makes the investments and builds the infrastructure to eventually power itself with wind and solar. This line of reasoning has been so appealing to the Environmental Defense Fund, as well as to former Sierra Club Executive Director Carl Pope and New York City Mayor Michael Bloomberg, that all have gone on record as supporting fracking for natural gas. (The Sierra Club now opposes fracking.)
However, recent research challenges the assumption that shale gas is better for the climate than coal. In 2011, Robert Howarth, professor of marine ecology at Cornell University, led a study published in Climatic Change concluding that as much as 1.9% of the gas in a typical well escapes to the atmosphere during fracking, compared with 0.01% in a conventional gas well.29 This turns out to make an enormous difference: over short time frames, methane is 20 to 100 times as powerful a greenhouse gas as carbon dioxide. If Howarth’s figures are accurate, this means that life-cycle greenhouse gas (GHG) emissions from shale gas are 20% to 100% higher than those from coal on a 20-year time frame basis.
Howarth’s conclusions were reported in the New York Times30 and immediately triggered a firestorm of vitriolic criticism from the industry—and from a few environmental organizations. A Forbes article later noted that “almost every independent researcher—at the Environmental Defense Fund, the Natural Resources Defense Council, the Council on Foreign Relations, the Energy Department and numerous independent university teams, including a Carnegie Mellon study partly financed by the Sierra Club—has slammed Howarth’s conclusions.”31
The critics insisted that Howarth had greatly overestimated leaks from fracked wells. National Energy Technology Laboratory (NETL) scientist Timothy Skone provided evidence for this view in a lecture at Cornell titled “Life Cycle Greenhouse Gas Analysis of Natural Gas Extraction & Delivery in the United States”; soon afterward, Lawrence Cathles, a Cornell geology professor, similarly argued—in a commentary published in Climatic Change—that Howarth’s fugitive methane figures were 10 times too high.32
How could scientists analyzing the same phenomenon arrive at such starkly different conclusions? Three main variables are keys to understanding the discrepancy. The first is the actual level of methane emissions during the drilling and fracking of a typical shale gas well. This number must be amortized over the total lifetime production of the well in question, as most of the “fugitive” methane escapes during drilling rather than during later production. Hence the second variable: the actual lifetime cumulative production figure for a typical well in the given formation. The third significant number indicates the amount of natural gas that leaks from pipelines on its way to the end user. The total amount of gas leaked to the atmosphere (from all phases of production and distribution) must remain below about 3.2% of all gas produced if natural gas is to have a climate advantage over coal over the next few critical decades, during which society must avert catastrophic climate change.33 In 2012, my colleague at Post Carbon Institute, geologist David Hughes, helped clarify issues in the dispute in a report titled “Life Cycle Greenhouse Gas Emissions from Shale Gas Compared to Coal: An Analysis of Two Conflicting Studies.”34 Hughes found that Howarth’s critics were lowballing per-well methane leaks during drilling and overestimating likely lifetime per-well production figures. He concluded that if these numbers are corrected, “the result is not significantly different from the conclusions of Howarth et al.”
Some recent measurements of actual methane emissions during drilling have come down strongly on Howarth’s side. A study by the National Oceanic and Atmospheric Administration (NOAA) reported that fully 4% of the methane gas being produced in the Wattenberg field in Colorado was leaking to the atmosphere; in a subsequent study, the same NOAA team found that 9% of produced gas was leaking to the atmosphere in a large natural gas field on mostly Indian land in north central Utah.35 On the other hand, the research arm of ExxonMobil has published a study insisting that fugitive methane leaks from fracking are less than 1% of the gas produced, though this was based on a generous estimate of lifetime production from a typical Marcellus shale gas well.36 The US Environmental Protection Agency recently downgraded its estimates of methane leaks in America’s natural gas production and distribution system, but this action was based on industry-funded studies (like the one just mentioned) rather than new direct measurements, and it did not take into account the recent NOAA data.37
Fugitive emissions of natural gas from pipelines (the third significant number) are still relatively poorly understood. A recent study of leaks from gas pipelines under Manhattan streets yielded numbers well above previous estimates for distribution leakage; the subsequent report estimated, on the basis of measured pipeline leaks, that the total of production losses and transmission losses for natural gas used in New York City must be above 5%.
Can drilling, production, and transmission leaks be plugged? Yes, in principle.38 And of course, industry should do everything in its power to reduce fugitive methane emissions. But recent data suggest that both drillers and pipeline operators have a big job on their hands.
Meanwhile, for the time being, the evidence is strong that current full-cycle greenhouse gas emissions for natural gas—especially from fracking—are worse than those for coal over the first 40 years. From the standpoint of climate stabilization, fracking for gas may be a bridge to nowhere.
We’ve been told that the economic and climate benefits of fracking (the latter in the case of natural gas, not oil) outweigh the risks to the immediate environment and to human health. But if evidence we’ve surveyed in the last two chapters is credible, then the real benefits of this technology have been exaggerated, and the risks substantially downplayed.
When benefits are systematically hyped and risks are unrealistically minimized, the results are bad investments and bad government policy.
1. Felicity Barringer, “Hydrofracking Could Strain Western Water Resources, Study Finds,” New York Times, May 2, 2013.
2. Sandra Postel, “As Oil and Gas Drilling Competes for Water, One New Mexico County Says No,” National Geographic, May 3, 2013.
3. Ian Urbina, “Regulation Lax as Gas Wells’ Tainted Water Hits Rivers,” New York Times, February 26, 2011, “Report: Fracking’s ‘Radioactive Wastewater’ Discharged into Drinking Water Supplies,” Environmental Leader (website), March 1, 2011. Abby Zimet, “Fracking Debris Ten Times Too Radioactive for Hazardous Waste Landfill,” Common Dreams (blog), April 25, 2013.
4. Ian Urbina, “Regulation Lax as Gas Wells’ Tainted Water Hits Rivers,” New York Times, February 26, 2011. Urbina references EPA documents (2011) obtained by the New York Times.
5. Sheila M. Olmstead et al., “Shale Gas Development Impacts on Surface Water Quality in Pennsylvania,” Proceedings of the National Academy of Sciences, March 11, 2013, doi:10.1073/pnas.1213871110.
6. Brett Walton, “Study: Shale Gas Fracking Taints Rivers in Pennsylvania,” Circle of Blue (website), March 21, 2013.
7. Anthony R. Ingraffea, “Fluid Migration Mechanisms Due to Faulty Well Design and/or Construction: An Overview and Recent Experiences in the Pennsylvania Marcellus Play,” Physicians, Scientists and Engineers for Healthy Energy (website), October 2012, 8–9.
8. Maurice B. Dusseault, Malcolm N. Gray, and Pawel A. Nawrocki, “Why Oilwells Leak: Cement Behavior and Long-Term Consequences,”(paper presented at the SPE International Oil and Gas Conference and Exhibition, Beijing, China, November 7–10, 2000).
9. Diane Ryder, “Report on Bainbridge Well Problem Released,” News–Herald, September 11, 2008.
10. Stephen G. Osborn et al., “Methane Contamination of Drinking Water Accompanying Gas-well Drilling and Hydraulic Fracturing,” Proceedings of the National Academy of Sciences 108, no. 20 (May 17, 2011), doi: 10.1073.
11. Deborah Solomon and Russell Gold, “EPA Ties Fracking, Pollution,” Wall Street Journal, December 9, 2011, .
12. Ellen Cantarow, “The Downwinders: Fracking Ourselves to Death in Pennsylvania,” TomDispatch.com (blog), May 2, 2013.
13. Joe Spease, Chairman, Kansas Sierra Club Fracking Committee, Testimony on Risks of Hydraulic Fracturing, (testimony, Kansas Legislature), January 31, 2012.
14. Peter Lehner, “Fracking’s Dark Side Gets Darker: The Problem of Methane Waste,” Natural Resources Defense Council Staff Blog, October 15, 2012.
15. Jon Hurdle, “US Gas Drilling Boom Stirs Water Worries,” Reuters, February 25, 2009.
16. Philip Doe, “A Must Read Account of Fracking Colorado,” EcoWatch (website), March 5, 2013.
17. Lisa Song, “First Study of Its Kind Detects 44 Hazardous Air Pollutants at Gas Drilling Sites,” InsideClimate News (blog), December 3, 2012.
18. In West Virginia and parts of Pennsylvania, most landowners do not own subsurface mineral rights and thus have no say in whether their land is drilled.
19. Ohio Ecological Food and Farm Association, “Fracking and Farmland: What Farmers and Landowners Need to Know About the Risks to Air, Water, and Land,” Fracking Factsheet, September 27, 2011, .
21. Oswald Bamberger, “Impacts of Gas Drilling on Human and Animal Health,” New Solutions 22, no.1 (2012): 51–77, doi: 10.2190/NS.22.1.e. 22.Judith Kohler, “Report Says Drilling Threatens Colorado Wildlife,” Aspen Times, January 20, 2010.
23. Katy Dunlap, Eastern Water Project Director, Trout Unlimited, Shale Gas Production and Water Resources in the Eastern United States, (testimony, US Senate Committee on Energy and Natural Resources, Subcommittee on Water and Power), October 20, 2011, . Susan Young, “EPA to Regulate Fracking Waste Water,” Nature News Blog, October 21, 2011, .
24. Katie M. Keranen et al., “Potentially Induced Earthquakes in Oklahoma, USA: Links Between Wastewater Injection and the 2011 Mw 5.7 Earthquake Sequence,” Geology (first published on March 26, 2013), doi: 10.1130/G34045.1. Becky Oskin, “New Mexico Earthquakes Linked to Wastewater Injection,” Live Science (website), April 23, 2013, .
25. “Loss of Property Values, Difficulty Getting Mortgages and Home Insurance,” Save Colorado From Fracking (website), .
26. Jeff Abbas, “Farming, Foraging and Fracking: Our Fight Against the Machine,” Resilience.org, March 26, 2013, . Steve Horn and Trisha Marczak, “Sand Land: Fracking Industry Mining Iowa’s Iconic Sand Bluffs in New Form of Mountaintop Removal,” DeSmogblog.com (blog), April 30, 2013, .
27. Dr. Wayne Feyereisn, “Potential Public Health Risks of Silica Sand Mining and Processing,” (presentation hosted by Concerned Citizens for St. Charles, St. Charles, MN), March 7, 2013, .
28. US Environmental Protection Agency, Inventory of US Greenhouse Gas Emissions and Sinks: 1990–2010, (Washington, DC, April 15, 2012), Energy 3-5, . The EPAmeasured each source of energy by its carbon (C) intensity in comparison to coal.
29. Robert Howarth, Renee Santoro, and Anthony Ingraffea, “Methane and the Greenhouse-Gas Footprint of Natural Gas from Shale Formations,” Climatic Change 106, no. 4 (June, 2011): 679–690, doi: 10.1007/s10584-011-0061-5.
30. Tom Zeller Jr., “Studies Say Natural Gas Has Its Own Environmental Problems,” New York Times, April 11, 2011, .
31. Jon Entine, “New York Times Reversal: Cornell University Research Undermines Hysteria Contention That Shale Gas Is ‘Dirty’,” Forbes, March 2, 2012, .
32. Lawrence Cathles et al., “A Commentary On ‘The Greenhouse-Gas Footprint Of Natural Gas In Shale Formations’ by R. W. Howarth, R. Santoro, and Anthony Ingraffea,” Climatic Change 113, no. 2 (July 2012): 525–535, doi: 10.1007/s10584-011-0333-0.
33. Ramón A. Alvarez et al, “Greater Focus Needed On Methane Leakage From Natural Gas Infrastructure,” Proceedings of the National Academy of Sciences 110, no. 13, (March 11, 2013): 4962–4967, doi:10.1073/pnas.1202407109.
34. David Hughes, “Lifecycle Greenhouse Gas Emissions from Shale Gas Compared to Coal: An Analysis of Two Conflicting Studies,” Post Carbon Institute, July 2011, 16–18, .
35. Jeff Tollefson, “Methane Leaks Erode Green Credentials of Natural Gas,” Nature 493, no. 7430 (January 2, 2013), .
36. Ian J. Laurenzi and Gilbert R. Jersey, “Life Cycle Greenhouse Gas Emissions and Freshwater Consumption of Marcellus Shale Gas,” Environmental Science and Technology 47, no. 9 (April 2, 2013): 4896–4903, doi: 10.1021.
37. “EPA Methane Report Further Divides Fracking Camps,” Associated Press, April 28, 2013.
38. Tim McDonnell, “Frackers Are Losing $1.5 Billion Yearly to Leaks,” Mother Jones, April 5, 2013.