Photo of a fracking well near Mainesburg, PA in 2011. Credit: Gerry Dincher, flickr creative commons


Many people worry about the potential health effects of hydraulic fracturing, or “fracking,” but there are few studies that quantify what risks there might be.

By Gabe Rivin

Depending upon whom you ask, hydraulic fracturing is either a catastrophic risk for public health in North Carolina or offers an economic boon with a proven ability to operate safely.

But a recent review of academic research suggests that neither side may be right – at least given the current lack of academic research.

A smaller natural gas drilling rig.
A smaller natural gas drilling rig. Photo courtesy North Carolina Department of Environment and Natural Resources

The review’s authors say they found no studies that address unconventional drilling’s health effects from water contamination. They found “relatively few” studies addressing air pollution’s health effects.

“There is an inadequate amount of information to make decisions that would be responsive to public concerns,” said Bernard Goldstein, a professor emeritus at the University of Pittsburgh Graduate School of Public Health and a coauthor of the review.

The authors’ findings come as North Carolina regulators are speeding to finish their work by October on a suite of fracking and drilling regulations. If the General Assembly approves the rules, the state will be able to issue drilling permits, which could arrive as early as next year.

Fracking opponents in North Carolina have claimed that the regulators place a higher value on energy development than public health. Regulators say the draft rules are strong, since they draw from the best practices of other states – even though, at times, regulators have had little science upon which to base their rules.

Yet the recent review suggests an alternative to the polarized narrative: Current research isn’t well equipped to say whether either side is right.

Threats to residents’ and workers’ health

The research may be slim, but that doesn’t mean unconventional gas drilling is necessarily safe, according to the researchers, who published their findings late last month in Environmental Science and Technology, a peer-reviewed academic journal.

In their literature review, the authors lay out an exhaustive list of potential threats to human health.

Drilling sites host a large number of incoming and outgoing trucks, for example, which can leave nearby areas awash in diesel exhaust and nitrogen oxides. The latter, according to the U.S. Environmental Protection Agency, contributes to the formation of ground-level ozone, which can cause lung damage.

Gas drilling also appears to increase airborne benzene, the review says. Benzene, even when inhaled for a short period, can cause dizziness, eye irritation and a loss of consciousness, according to the EPA.

Gas-rig workers may face a particular health risk. Workers handle silica, a chemical that helps to prop open shale rock during the fracking process. But silica can turn into a dust, which is carcinogenic when inhaled, according to the review.

Perhaps most controversial is fracking’s potential to contaminate water. The review’s authors echo other researchers, however, who have found that fracking in itself does not appear to cause water contamination. Instead, accidents and malfunctions, such as leaky gas wells, appear most likely to be the sources of contamination.

‘A number of scientific limitations’

The researchers note several studies that have raised concerns about gas drilling. One study, for example, found that pregnant women who lived near gas wells gave birth in greater rates to children with congenital heart defects and neural tube defects. (That study’s lead author, Lisa McKenzie, was one of the coauthors of the recent review.)

Yet many of the current studies “have had a number of scientific limitations, including self-selected populations, small sample sizes …  limited exposure measurements and/or lack of access to relevant exposure data,” among other limitations, they say.

These limitations don’t necessarily prove that drilling’s byproducts are unsafe, however.

Robert Jackson, a Duke University geochemists, sampled well water in northeastern Pennsylvania, a hotbed of gas drilling. Residents who lived near gas wells, Jackson and a group of scientists found, had a greater amount of methane in their well water.

Jackson said that he could not find any studies assessing the health effects of methane in drinking water.

“Just because there hasn’t been any work done that I can find – and I have looked – that does not mean that there are large health effects,” he said. “It just means that there isn’t peer-reviewed literature looking at it.”

For other, well-studied chemicals, scientists can infer health risks if they have information about people’s exposures to the chemicals, said Goldstein.

With proper pollution monitoring, he said, scientists can use “standard approaches that have long been in use” to assess the pollution’s threat to human health.

How N.C. regulators have responded to uncertainty

According to the review, public-health researchers have much to learn about unconventional gas drilling.

But that conclusion is not accurate, said Jim Womack, chairman of the N.C. Mining and Energy Commission, which is developing fracking and drilling regulations.

“There is an enormous body of work that has been dedicated to hydrocarbons over the last one hundred years,” he said. “The reason you don’t see shale energy specialized is because it’s the same byproducts, the same products that have already been studied.”

Womack added, “We know what the carcinogens are; we know what the toxic chemicals are that are used both in the process and that are in the extracted product.”

In the law that legalized fracking, the General Assembly required the M.E.C.’s rules to protect public health.

Womack said that the commission has taken objective measures to protect public health. He noted too that the North Carolina rules incorporate several federal requirements, including prohibitions against the use of certain chemicals while fracking.

But some environmentalists say the M.E.C.’s requirements are not enough.

“Unfortunately, while the Commission has worked on an expansive package of rules, it has not prepared any kind of rule to establish baseline epidemiological data, or to track public health impacts broadly – so there’s no real framework for capturing [public health] impacts,” wrote Grady McCallie, policy director of the N.C. Conservation Network, in an email interview.

Energy companies say that no new health studies are necessary, since gas drilling is a decades-old practice, Goldstein said. But, given the major technological developments in drilling, that mentality risks “getting the public at least confused and concerned, and wondering if in fact they’re being told the whole story,” he said.

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Gabe is our former environmental health reporter from 2014-2016. He is a former editor of The Cooperative Business Journal, and a former reporter for Inside Washington Publishers, where he covered federal...