The Growing Evidence of the Threat of Fracking to the Nation’s Groundwater

For some time now, proponents of the controversial practice of hydraulic fracturing or “fracking” have claimed there was little or no evidence of real risk to groundwater. But as the classic saying goes: “the absence of evidence is not evidence of absence” of a problem. And the evidence that fracking can contaminate groundwater and drinking water wells is growing stronger with every new study.

As most people now know, fracking is a method for enhancing the production of natural gas (or oil, or geothermal energy wells). Fracking involves injecting fluids -- typically complex mixes of water and chemicals – under high pressure into wells to create cracks and fissures in rock formations that improve the rates of production.

Whether you support or oppose fracking depends on many complex factors: the economics of the practice, perceptions about the implications for national security of relying on domestic or imported energy, the consequences for climate change from the emissions of different amounts of greenhouse gases from different energy strategies, the positive and negative implications of fracking for employment and quality of life in rural communities, and the scientific evidence about the environmental consequences of the practice, including risks to water availability, water and air quality, and local ecosystems.

Some of the most significant environmental concerns associated with fracking are related to impacts on water. In 2012, the Pacific Institute released a major study on these water-related risks. These risks include growing competition for limited water resources; the production of large volumes of contaminated wastewater that comes up with the oil or gas and must be treated, reinjected, or otherwise safely stored; truck traffic and its impacts on the water quality of streams; spills and leaks; and the risks of groundwater contamination from the drilling and fracking process or from surface seepage of improperly handled wastewater. Ceres recently released a map showing that many fracking operations are occurring in regions of the US where water stress is already a real problem.

This map, produced at, shows that nearly half of all US shale gas and oil wells are being developed in regions of the US with high to extremely high water stress. The research is based on well data from This map, produced at, shows that nearly half of all US shale gas and oil wells are being developed in regions of the US with high to extremely high water stress. The research is based on well data from

The Pacific Institute analysis concluded that a lack of credible and comprehensive data and information makes it much more difficult to identify or clearly assess the key water-related risks associated with hydraulic fracturing and to develop sound policies to minimize those risks. While much has been written about the interaction of hydraulic fracturing and water resources, the majority of this writing is either industry or advocacy reports that have not been peer-reviewed. As a result, the discourse around the issue is largely driven by opinion. Only by comprehensive and careful independent testing and monitoring is it possible to assess the full environmental and public health risks of fracking and identify strategies to minimize these risks This is particularly true for groundwater contamination, which is hard to measure, hard to monitor, and hard to track.

Because of the limited amount of data, some industry proponents have long claimed that fracking is safe. Indeed, we sometimes see statements at odds with actual scientific evidence. Here is one from the American Petroleum Institute:

 “There are zero confirmed cases of groundwater contamination connected to the fracturing operation in one million wells hydraulically fractured over the last 60 years.”

Another industry proponent recently described the risks of groundwater pollution from fracking as “almost inconceivable.”

“Inconceivable”? That brings to mind the classic scene from the film Princess Bride, where Inigo Montoya says to Vizzini: “You keep using that word. I do not think it means what you think it means.” [Here is a link to a 10-second clip from the movie: enjoy.]

In fact, even with the limited research done to date, there is clear scientific evidence that fracking not only can -- but already has -- led to groundwater contamination, including a new study just released this week. Here are just seven separate lines of evidence:

  1. As far back as 1984, the USEPA reported on a clear case in which hydraulic fracturing fluids and natural gas from production operations contaminated a groundwater well in West Virginia, “rendering it unusable.”
  2. The USEPA issued a draft report in 2011 on groundwater contamination in Pavillion, Wyoming, that showed extensive presence of fracking chemicals (natural and synthetic) in shallow and deep groundwater systems. Some of this contamination may have resulted from faulty wells drilled through groundwater aquifers; some of it may have resulted from surface seepage of fracking waste fluids escaping from badly designed and managed wastewater pits.
  3. The US Geological Survey Report issued its own independent assessment of the Pavillion, Wyoming groundwater testing that also showed high concentrations of several chemicals used in fracking.
  4. A Canadian groundwater contamination report described a “hydraulic fracturing incident” in 2011 in which errors in well drilling and management led to the release of fracking chemicals into groundwater including isopropanolamine, benzene, toluene, ethylbenzene, xylene, petroleum hydrocarbons, and more.
  5. A Duke University peer-reviewed study showed that fracked groundwater systems pose risks to other groundwater systems that were thought to be, but were not, hydraulically separate. This study clearly shows the risks in some groundwater geologies of cross contamination.
  6. Even more compelling, another peer-reviewed study published in the Proceedings of the National Academy of Sciences documented “systematic evidence for methane contamination of drinking water associated with shalegas extraction.”
  7. The latest peer-reviewed study, released this week, also shows strong evidence that increased concentrations of methane and other hydrocarbons in drinking water wells are directly correlated with proximity to gas wells in the Marcellus Shale region of Pennsylvania.

This growing evidence of a real threat to some of the nation’s valuable groundwater makes it all the more disturbing to learn that the US EPA is halting its own independent assessment of groundwater contamination from fracking in the Pavillion gas fields of Wyoming and even worse, turning that research over to a project funded by the fracking company itself. This smells rotten and is not how independent research should be done.

Far more and better research is needed, and public agencies must demand that monitoring data be independently collected, analyzed, and publicly released. But the evidence already available shows that fracking threatens our water resources. I repeat my comment above: the net effects of fracking depend on a complicated mix of the risks and benefits of the process and how one evaluates, perceives, values, and weighs those effects. But no smart public policy can be made if we turn a blind eye to the risks, fail to pursue comprehensive independent science, or even worse, deny the science and the evidence already available to us.

Peter Gleick

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No question, the Alberta report documents contaminated groundwater during a frack operation. The company mistakenly perforated the casing (which they have to do in order to be able to inject the fluids into the rock from the well) over a very shallow rock section.

The 1984 EPA report is far less certain, however. There are alot of "may"s in there, alot less analytical data, and far less certainty than to draw a firm conclusion that fracking rendered the groundwater unusable.

As for the Duke studies, even the authors aren't blaming fracking anymore, but crappy casing jobs allowing gas to migrate upward beside the wells. Further, the first of those papers spawned some comments that discussed whether that methane might've been there before the drilling ever took place (there is plenty of shallow thermogenic gas in the northeastern U.S.) and whether it's possible that fluids can move up from about a mile depth in the intervening rock. Thus, their results are far from certain (though probably correct in Dimock, where it was indeed found that gas wells with faulty casing contaminated groundwater).

As for the Duke study on whether deep systems are hydraulically connected to the surface, this finding flatly contradicts decades of the understanding of hydrogeology in petroleum systems (that deep systems are almost completely isolated from shallow systems: deep saline water almost never moves upward because it's more dense than freshwater at surface). The Duke study also didn't give a timescale for the intrusion of salt water upward to even make it possible to determine whether this is possible on a human time scale. Two papers (both rebuttals to Myers, 2012, a paper that tried to use MODFLOW to demonstrate that deep-to-surface communication was possible, something that the model was never intended for and is not really capable of determining) demonstrate the high ulikelihood of this very well.…

Further, if gas could move that freely from depth to surface, there would not be a puff of gas anywhere under the earth in any formation, shallow or deep, as it would've leaked out millions of years ago. Marcellus gas was generated hundreds of millions of years ago and remains overpressured, suggesting it's been stuck in place for all that time and that the seals overhead (and there are far more than one seal and they're very thick) have very solid integrity that fracking would not change (it's well known the fractures don't extend more than 600 m upward even in the most aggressively fracked wells, more likely only a few hundred metres in most wells, and this is measureable using microseismic). There'd be no gas worth drilling for at all. Let's not forget that gas only moves upward until it hits a permeable formation, then it goes laterally because it's taking the path of least resistance (this, of course, would divert it from rising any further).

As for the USGS study on Pavillion, the USGS also found that they couldn't find many of the chemicals the EPA said they could. Plus, the data from re-testing the EPA test wells suggests there's a halo of contamination around them, likely caused by the cement the EPA used (the potassium concentrations that the EPA said came from fracking kept steadily dropping and never reached a baseline). Plus, while the EPA suggested KOH was used in the frack fluids and would explain the high pH in the samples they took, something that they used as a main argument in making the link between fracking and groundwater quality, state regulatory records indicate KOH wasn't used but CO2 foams instead, which should decrease pH, not raise it.

That's not the only significant problem with the EPA Pavillion study (for example, they also didn't do any hydrogeological mapping to determine whether it was possible for the fluids to move upwards, something that should be standard in any ground-water contamination case study, especially one that said frack solutions were moving upward, which is unusual). The problems are numerous and it's probably a good thing they retracted it or it was going to get butchered in peer review and then they'd lose even more credibility over this.

Now, I have absolutely no love for the oil and gas industry. They've obviously engendered very little trust because of their denial of climate change and resistance to many regulations that would greatly enhance protection of the environment. There is very good evidence that shoddy well casing has resulted in contaminated groundwater in Pennsylvania and elsewhere. I have no doubt in my mind that their bleating about using gas to displace coal to lower GHG emissions is a selling point only and, if that wasn't possible, they'd be back to denying GHG emissions are a problem at all. The Pavillion EPA study indicates abandoned surface pits likely contributed to poor groundwater quality in the shallow aquifers. Finally, I like the EPA's mission and they have a definite role in ensuring water quality and air quality in the U.S., as well as regulating CO2 emissions when congress won't pass legislation to do it, though I found EPA's methodology and conclusions for the Pavillion study sorely lacking.

But fracking very likely isn't the culprit except for a handful of cases (like the Alberta example). Where oil and gas activity is responsible, poor well casing and surface activity almost certainly is.

By Miguelito (not verified) on 27 Jun 2013 #permalink

Thank you for taking the time, and effort, to write a detailed and informative post, adding information about the cases and questions I've raised. I guess my overall response is that, despite the uncertainties and criticisms of various of the studies (some of which may be valid, of course), the bottom line is where you ended: "a handful of cases" "poor well casing" "surface activity" "crappy casing jobs" are all real risks. Well done fracking operations may pose little or no risk: but millions of wells, poorly monitored, will cause more and more problems. Even if one-tenth of a percent (0.1%) of wells are "crappy" or "poor", that is still 1,000 wells that may cause groundwater problems. If society is going to accept fracking, we have the right to insist on better regulation, monitoring, enforcement....

It seems all the documented incidents of contamination involve spills, well casing failure and negligence. If this is the case, there is no evidence that hydrolic fracturing as a tequneque is causing damage (as most opposition claim), but that poor practices cause damage. An obvious cause of these incidents could be lack of regulation and oversight.
However, It would be necvisary to compair incident rates involving fracing with those of other energy reasource extraction.

Personally, I work at a facility that extracts a reasource from via solution mining from a deposit 5-10 feet above a heavily utilized gas formation. Over the last 5-10 years more than 15 fracted wells have gone in around and under our location. Not being exempted from the clean water act we monitor ground water for contaminants every week, and have found no change since the fracing began. We take the issue seriously as contamination from these wells could potentially gravely impact our operation.

From what I have seen and read, hydrolic fracturing is safe as long as good practice is fallowed. If there is a problem with the implementation of this technology, it should be addressed with regulation monitoring.

Unfortunately the Oil and Gas industry use the "Drill first go to court later" business model. Also, thanks Peter, it's good to see my old man's quote being used in the right way every now and then, (Absence of evidence is not evidence of absence). He was an Astrophysicist.

By Dimitrios Papa… (not verified) on 27 Jun 2013 #permalink

Peter: absolutely, society has a huge interest in making sure things are done right. The regulations, monitoring, and enforcement have to be there to get that social licence. The IEA proposed some golden rules that would only increase well costs by 7%.,27266,…

The problem is that industry typically fights any attempts to improve standards. Typically, of course, but not always: in Pennsylvania, there's a coalition between some of the big industry players and environmentalists to set some real standards. In Illinois, new regulations were set and were accepted by some environmentalists and some industry. That being said, that's not the norm and that's disappointing.

By Miguelito (not verified) on 27 Jun 2013 #permalink

Miguelito and Thad, it seems to me that the separation between fracking and processes necessary to implement it is meaningless in practice.
As an analogy, consider if there has been an epidemic of collapses in new buildings. Would you accept the protest "It's just because some construction firms used substandard steel, nothing to worry about"?

Dick, if there were some building collapses would it be more useful to ban all building projects or Thales a look at what caused the collapses and solve the problem, furthermore suppose these buildings were of a new design and when compared to existing designes colapsed with the same rate( of course in reality there is no acceptable collapse rate for buildings). Would it be logical to ban the new design while leaving the old design regulations the same?

We can all agree here that the use of carbon based fuels is one of the biggest problems facing is inofern times. Steps need to be taken to turn the trends around, however banning exploration and extraction of natural gas for the same rate of pollution as other drilling logically leads to banning ALL drilling, if you want that take your house off of the power grid(a good option if you can afford wind and solar units) do not drive any car gas or electric charged with the national power grid, do not buy any product that contains or is produced with the help of plastics, eat only non fertilizer grown food, and perhaps we can get the transition accomplished faster.

I totally agree that there are real risks, particularly around poor casing work and water management practices (and, moreso, from treating shale gas as a transition fuel without any policies to back that up - I worry constantly that we have lulled ourselves into complacency around NG's entirely insufficient ability to mitigate climate change.)

However, what I came to say is that, like Vizzini's 'inconceivable', I think that we as scientists and public technical voices need to consciously avoid using 'fracking' as the catch-all term it has become. Not only does it not accurately reflect where many problems originate, but we will lose the debate every time against companies who use it more specifically to retort claims of problems.

I understand (intimately) that this is a battle over public discourse that is hard to affect, but we - you! - should know better and act better, in an effort to improve the quality and accuracy of that discussion.

Alex, thank you for the comment. I partly agree -- the term is used loosely as a overarching reference to processes used to extract difficult to access fossil fuels. I use it, and used it in this post, to refer to hydraulic fracturing techniques (applied largely to NG but also to oil and to some degree geothermal wells). Moreover (and perhaps this is your point), some of the groundwater contamination results from inappropriate surface disposal of waste fluids, not the actual well operations themselves. We make this point very clearly in the paper we released on this topic.….