Dept. of Fracking: Three Studies Examine Drilling Risks

  • A drilling rig on a Marcellus shale well pad near a Butler County, Pa. farm in April, 2014. Photo: Reid R. Frazier

September 16, 2014

Three studies shed light on what’s safe, and what isn’t, about hydraulic fracturing.

A slate of recently published scientific studies show what aspects of natural gas development are of concern to the environment and public health, and what aspects might not be.

In a study published in the Proceedings of the National Academy of Sciences, a team of researchers focused on eight known clusters of gas migration in Pennsylvania and Texas. They then measured the gas isotopes, or ‘fingerprint’, to determine where the contamination came from.

In four of the areas, the researchers found that the gas contamination was a result of failures in cementing of the wells. In three wells, the problem was a faulty casing. In one of the cases, the problem was a failed gas well.

Significantly, the authors found that no evidence that contamination appeared to be the result of fracking—the high-pressure pumping of millions of gallons of water, sand and chemicals into carbon-rich rock formations in order to fracture the rock and recover oil and gas.

“Our data do not suggest that horizontal drilling or hydraulic fracturing has provided a conduit to connect deep Marcellus or Barnett Formations” to groundwater above the wells, the authors wrote. 

These results echo the recently published findings of Penn State Professor Terry Engelder. Engelder found last week that fracking chemicals do not migrate to the surface after hydraulic fracturing. More than half of the water and chemicals that get pumped into the ground during fracking stay underground. Scientists have suggested this liquid mix of chemicals and naturally occurring metals, salts, and radioactive materials could migrate upward through naturally occurring pathways.

Engelder’s study, however, demonstrated that the physical properties of shale formations in Pennsylvania and Louisiana keep these liquids, in effect, permanently sequestered.

While those two studies focused on the condition of water below ground, a third study focused on the health of people above it. A study in Southwestern Pennsylvania showed that health impacts for those living near gas wells increased the closer their home was to a well.

Researchers from Yale randomly sampled 492 people in 180 households in Washington County. The respondents were asked whether they’d experienced a variety of symptoms.

The self-reported survey showed that those living closest to wells exhibited higher reported skin and upper respiratory symptoms than those who live further away. No correlation was found for other symptoms, like neurological, heart, or gastrointestinal disease.

Though the authors stressed the study cannot say whether gas drilling activities caused the uptick in self-reported health problems, “proximity of natural gas wells may be associated with the prevalence of health symptoms.” The gas industry questioned the study's methods.