Long-awaited EPA Study Shows How Fracking Contaminates Drinking Water

UPDATE (June 24, 2015): Last week, the University of Texas at Arlington released a study finding widespread contamination of drinking water from fracking. The study examined 550 drinking water wells located near fracking operations on the Barnett shale in northern Texas. 69 percent (381) of the wells tested positive for BTEX chemicals, which are associated with oil and gas development and do not occur naturally in water. BTEX stands for benzene, toluene, ethylbenzene, and xylenes, four toxic chemicals linked to serious health risks ranging from cancer to neurological effects. This study highlights the public health risks of fracking and rebuts the EPA study’s claim that water contamination from fracking operations is not a widespread problem. 


A U.S. Environmental Protection Agency (EPA) study that was five years in the making was released yesterday.  Its un-news: fracking can contaminate drinking water sources. The report acknowledges what scientists, environmental groups, and communities living near drilling sites have been arguing for years. However, EPA’s questionable statement that the problem is not “widespread” seems unmerited given the limitations of the methodology and the data, and it downplays the critical findings of the report. 

For years, the oil and gas industry has denied that fracking pollutes drinking water.

The oil and gas industry has spent an enormous amount of money trying to convince the American public that fracking is safe and to discredit claims that it can contaminate drinking water. For years, there were few scientific studies on fracking's impacts, allowing industry to push back against health and safety concerns over the drilling practice.

And, although the oil and gas industry asserts that fracking is safe, it has been largely uncooperative with researchers. EPA’s study was supposed to be released in 2012 but was delayed in part because of industry’s refusal to provide locations and data essential to the study. These hurdles, combined with a lack of baseline water testing and limited access to information on the chemicals used in fracking, limited EPA’s ability to study fracking’s impacts on drinking water.

EPA's study highlighted instances where fracking has or potentially could contaminate surface and groundwater sources.

The agency reviewed scientific studies and data sources looking at water contamination during five stages of fracking:

  • Water acquisition is the withdrawal of surface and/or groundwater to use as fracking fluids. Significant water withdrawals may cause local wells or streams to run dry. EPA didn’t find an instance where this happened due to fracking alone but admits it remains a risk, given the enormous amounts of local water consumed by fracking and ongoing drought in regions where fracking is common.
  • Chemical mixing includes mixing base fluids (usually water) with chemical additives to form a fracking fluid. This is often done at the well pad, where human error and equipment failure can lead to spills. Comprehensive data on spills is limited, but EPA was able to calculate spill rates in two states. They found one spill per 100 wells in Colorado, and up to 12.2 spills per 100 wells in Pennsylvania. Average spills involve roughly 420 gallons of chemicals. Additionally, the fluids reached (i.e., contaminated) surface water in nine percent of spills that EPA examined. Chemicals can also saturate the soil and leach into groundwater sources, a process that can take several years and require long-term monitoring to detect.
  • Well injection includes injecting fracking fluids several thousand feet beneath the surface – through the water table – to unlock oil and gas from rock formations. Poor well casing can leach contaminants into underground drinking water sources. Even when well casings are intact, unique geological formations can cause chemicals to travel into drinking water. EPA cited several cases where drinking water has been contaminated through well injection, including in states like Ohio and Colorado.
  • Produced water is the set of fluids that return to the surface during injection. This can be freshwater or loaded with salt, and it may contain everything from chemical additives to cancer-causing substances like benzene and cadmium. EPA looked at 225 spills in 11 states involving produced water, eight percent of which resulted in contamination of ground or surface water. The average amount spilled was 990 gallons. The largest spill ever occurred in North Dakota and involved 2.9 million gallons of salty water that leaked into nearby creeks.
  • Wastewater disposal involves disposing of produced waters. This waste may be stored temporarily in an open pit on site, injected underground, or sent to a public water treatment facility. When water used in fracking is sent to public water facilities, it can contaminate water supplied if the facilities can’t handle large volumes of toxic water.


Despite documenting millions of gallons of toxic spills across the U.S., EPA concluded that, compared to the enormous number of fracking wells, water contamination is not a “widespread” issue.


But given the significant gap in available data on fracking wells – largely due to industry secrecy – EPA doesn't really know how widespread the problem is.

The agency acknowledges limitations in the study. No reliable data on the total number and location of fracking wells exists. Well operators usually do not conduct water tests before or after drilling. And loopholes in chemical disclosure laws allow companies to hide information on the chemicals they use in fracking. Incredibly, EPA did not include underground wastewater injection in its study, a common form of wastewater disposal that has been shown to pollute groundwater

EPA’s finding that fracking has contaminated drinking water in many instances demonstrates the need for stronger standards and safeguards, better data collection (including, pre- and post-drilling water tests in order to establish reliable baselines), and ongoing oversight.

EPA’s study found that 8.6 million Americans rely on drinking water sources that are within one mile of a fracking well. These communities need to have their drinking water protected.

Photo by Flickr user Sarah Craig, used under a Creative Commons license.

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not surprising
I'd like to know the estimated lifetime of the well casing? Has there been any research into the average lifespan and how the eventual failure of those casings will effect everything around it? Who's responsible when the texas gas frackers have packed up and gone?
I'd like to know the estimated lifetime of the well casing? Has there been any research into the average lifespan and how the eventual failure of those casings will effect everything around it? Who's responsible when the texas gas frackers have packed up and gone?