This is a guest post by Jamie L. Vernon, Ph.D., a research scientist and aspiring policy wonk, who recently moved to D.C. to get a taste of the action

Recently, EPA Administrator Lisa Jackson stated that there is no evidence that the “fracking” process has lead to contamination of ground water. In response to a question from the U.S. House Oversight Committee, she said,

“I’m not aware of any proven case where the fracking process itself has affected water, although there are investigations ongoing.”

The term “fracking” refers to a process of extracting natural gas from wells drilled deep below the Earth’s surface. The technique is officially known as hydraulic fracturing and involves pumping a water-based fluid into a well under high pressure so as to cause the formation of cracks in deep rock layers. The cracks and the chemical ingredients in the fracture fluid facilitate more efficient extraction of the natural gas.

Critics of the process have made claims that hydraulic fracturing has contaminated aquifers and other water sources with ingredients from toxic fracking fluid in areas where natural gas drilling is occurring. A documentary entitled “Gas Land” recently sensationalized the story by showing scenes in which drinking water had become flammable. Here’s a famous scene from the movie:

The problem with the critics’ argument is there is insufficient evidence to prove that the contaminated water is indisputably due to fracking. The process has been used for many years and has not been scrutinized until recently. Despite the scrutiny, no one has carried out thorough investigations to determine whether the process is likely to lead to water contamination. Sure, there have been cases where it is suspected that the process has contaminated ground water. Indeed, I have blogged about it here at The Intersection, but with no analysis of the ground water prior to drilling, one cannot be sure that the contamination is directly caused by the fracking industry.

Personally, even though the evidence is sparse and inconclusive, I still believe the risks of contamination are too high for us to continue drilling for natural gas without significant oversight and regulation. A recent blowout in Bradford County, Pennsylvania has contaminated the immediate surrounding areas and three private wells with chemical-laced water. I feel strongly that fracking is unsafe as it is currently being carried out.

Fortunately, the Obama administration has made it a priority to take a look at the hydraulic fracturing industry. On Thursday, the EPA announcedthe seven natural gas drilling sites where it will conduct case studies. The investigations will look at the impact of hydraulic fracturing on local drinking water.

The sites include drilling in Haynesville Shale in DeSoto Parish, La., Marcellus Shale in Washington County, Bradford and Susquehanna, Pa., Bakken Shale in Kildeer and Dunn Counties, N.D., Barnett Shale in Wise and Denton Counties, TX, and Raton Basin in Las Animas County, Colo.

Here are my concerns about the EPA’s plan:

First, there is little or no evidence that the toxic ingredients in fracking fluid have contaminated drinking water directly from the below-ground wells. Dangerous chemicals like benzene and acrylamide are known to be part of the fracking mixture, but legislation has protected the industry under intellectual property rights from fully revealing the contents. Therefore, investigators have been unable to do proper testing for all the chemicals contained in the mixture. Regardless, it seems that the fracking fluid and, in fact, the fracking process is not the problem.

There are numerous physical arguments against the possibility that fracking fluid will find its way into drinking water during the hydraulic fracturing process. The pressures at those depths are so high it is unlikely the chemicals will be able to flow upward into the aquifer. Also, the permeability of the shale is so low it seems unlikely the chemicals will penetrate the rock. Of course, there is the possibility that the cracks created by the process could connect with natural cracks in the rock formations leading to a direct connection between the well and the aquifer, but this is statistically unlikely. My point is that if the EPA focuses on the fracking process alone it is unlikely that they will find a connection between drilling and contamination at the 7 selected sites.

As described in the PNAS paper, the problem of contamination is most likely due to leaky gas-wells, not the hydraulic fracturing itself. The EPA investigators will need to look at the wells as well as the fracking process. However, because the sites have been announced ahead of time, the drillers can take special precautions to ensure high quality wells are drilled and that the concrete is poured properly so as to avoid any leaks or spills. If so, investigators may not find any contamination.

Second, there are millions of natural gas wells across the country. Very few of them have been linked to any contamination. Statistically, for the EPA to choose only 7 wells, I believe it is highly unlikely they will find a correlation between drilling and contamination.

For me, the issue of water contamination due to the fracking process is not simply a yes or no question. It is a matter of risk. We must ask ourselves if we are willing to risk the possibility of water contamination occurring in our neighborhood. Given that few of the natural gas sites across the country have caused contamination, I think it is unlikely that the EPA study will demonstrate a direct correlation between hydraulic fracturing and water contamination. If this is the case, this study will do more harm than good by providing evidence, albeit faulty, for the gas industry to argue that fracking is safe. The real question is whether you are willing to take the risk of having undrinkable water. Are you?

I guess we can be thankful that the fracking process as it is being done today is very different from the plowsharing process proposed in the 70′s.

Let’s keep our eyes on this study and hope that it yields the results we need.

Follow Jamie Vernon on Twitter or read his occasional posts at his personal blog, “American SciCo.”