Fracking, or hydraulic fracturing, has been a process to extract a considerable amount of natural gas from underground shale formations. It has been quite a lucrative endeavor. A recent National Economic Bureau Research study (Gilje et al., 2016) shows that since 2012, fracking has increased aggregate U.S. equity market capitalization by $3.5 trillion, which says nothing of social costs or benefits. As the Brookings Institution points out, while there are economic gains to be made, there are still environmental concerns to be considered.
One such consideration is that of groundwater. Fracking produces the fractures in the rocks by injecting high-pressure amounts of fluids (usually water, sand, and chemical additives). After the injection, the internal pressure causes fluid to return to the surface through the wellbore. This flowback is stored on site in tanks or pits before treating, disposing, or recycling it. In many cases, the flowback is injected underground. The potential for the flowback to seep into groundwater is what has many concerned, but how valid is the concern?
The controversy behind fracking and groundwater dates back at least to 2011. In December 2011, the Environmental Protection Agency (EPA) released a preliminary report hinting at there being an issue with fracking and groundwater contamination in Pavilion, Wyoming, even though the then-EPA Administrator said that there is no definitive determination to be made. In 2013, the EPA handed it over to the Wyoming Department of Environmental Quality (DEQ). The evidence from the DEQ, released in November 2016, found that hydraulic fracturing fluids did not sink into water-supply wells, although a Stanford University study attempted to refute these findings a few months earlier.
Last week, the EPA released its own final report from its original investigation earlier this decade, the report that found no evidence of "widespread, systematic impacts on drinking water sources in the United States." This latest report redacts the portion that says there is no evidence of widespread groundwater contamination. However, the report concludes with hypotheticals in which fracking could be bad, such as injecting hydraulic fracking fluids directly into groundwater (Executive Summary, p. 42). One would think it would be obvious that injecting the fluids directly in the water would contaminate, but that is not inherent within the process. Nor does the disposal of inadequately treated wastewater into surface water (ibid.).
These are not the only studies that point to a lack of a threat to groundwater caused by fracking. A Duke University study (Jackson et at., 2013) saying the issue was faulty steel casings and improper sealing of the wells, and not fracking itself. The United Kingdom's Department of Energy and Climate Change came to a similar conclusion in their 2014 report on fracking that the issue is poorly crafted wells, not fracking per se (p. 3). Another study, this one from the National Science Foundation, found that the introduction of fracking in Colorado did not increase the likelihood of water contamination (Sherwood et al., 2016). There are also a 2011 United States Geological Survey study and a Yale University study (Drollette et al., 2015) showing that fracking does not have these particular systemic effects on groundwater. I don't mind taking measures to avoid preventable, accidental leakages and assessing the costs against the benefits of fracking. However, environmentalist fear-mongering on the hydraulic fracturing process that has brought the American people cheaper energy with less carbon emissions is folly.
6-20-2017 Addendum: The University of Texas' Academy of Medicine, Engineering, and Science of Texas just released a study on the environmental effects of fracking. What it ended up finding is that fracking does not contaminate groundwater, nor does it cause an earthquake hazard.