Last week, research into the connection between fracking and radon, an odorless, colorless, radioactive gas, drew international attention, making headlines in English, German and Italian.

The study, published in the scientific journal Environmental Health Perspectives, found that buildings in Pennsylvania counties where fracking is most common had significantly higher radon readings than the levels found in counties with little shale gas drilling — a difference that emerged around 2004, when the shale rush arrived.

The potential link between fracking and radon in people’s homes was surprising, the researchers, based at the Johns Hopkins Bloomberg School of Public Health, said.

“We found things that actually didn’t give us the reassurance that we thought it would when we started it,” Brian S. Schwartz, MD, a professor in the Department of Environmental Health Sciences at Johns Hopkins told the Baltimore Sun.

In a little-noticed move just one day after the Johns Hopkins report was released, a Pennsylvania court allowed the state’s environmental regulators to keep the public from reviewing data from radioactivity testing at oil and gas drilling sites.

Earlier this year, the Pennsylvania Department of Environmental Protection (DEP) had released its own study into the hazards associated with radioactive materials from the shale gas rush, concluding that there was nothing to worry about.

“There is little potential for additional radon exposure to the public due to the use of natural gas extracted from geologic formations located in Pennsylvania,” the report, published January 15, said.

That broad conclusion, critics charge, has been thrown into question by the preliminary findings from Johns Hopkins.

“One plausible explanation for elevated radon levels in people’s homes is the development of thousands of unconventional natural gas wells in Pennsylvania over the past 10 years,” Dr. Schwartz said in a statement. “These findings worry us.”

With renewed concern about a possible tie between fracking and radon in Pennsylvania residences, environmental groups have faulted the state for keeping some of its data on radon and other naturally occurring radioactive materials (NORM) from the shale rush confidential.

“The NORM report is supposed to inform an extremely important public health issue related to the effects of highly dangerous radioactive materials produced by fracking in the state,” said Tracy Carluccio, Deputy Director of the Delaware Riverkeeper Network, which had requested the data from the state. “It looks suspect and makes people wonder what they are hiding.”

A Legal Battle Over Data

Pennsylvania has a long history of naturally high radon levels, thanks in part to traces of uranium in state’s bedrock — one of the reasons that the Johns Hopkins researchers were able to collect over 2 million radon test results taken at over 800,000 different buildings in the state between 1987 and 2013.

Since the arrival of the shale drilling rush, Pennsylvania has also become the second-largest producer of natural gas in the U.S., behind only Texas, according to the Energy Information Administration.

In 2013, the Pennsylvania DEP‘s Bureau of Radiation Protection launched a study of radioactive material from the shale drilling industry.

Environmental groups have been keeping close tabs on radioactivity from shale drilling and fracking, after it was revealed in 2011 that for years Pennsylvania had allowed drillers to dump their radioactive wastewater at ill-equipped sewage treatment plants with virtually no testing to find out whether drinking water for towns and cities downstream was polluted as a result.

Internal E.P.A. memos called subsequent water contamination in the state “one of the largest failures in U.S. history to supply clean drinking water to the public.”

Doubts about the agency’s capacity to adequately police the burgeoning shale gas rush deepened in 2014 when Pennsylvania’s auditor general released a scathing report on DEP‘s oversight, finding that the agency was “underfunded, understaffed, and does not have the infrastructure in place to meet the continuing demands placed upon the agency by expanded shale gas development.”

In May 2014, DEP responded to Delaware Riverkeeper Network’s request for its sampling data by providing roughly 300 pages worth of information about a 1994 study on radioactivity and the then-underway radioactivity study, according to court records. But the agency refused to make public the remaining materials — over 57,300 pages containing 3,495 samples and surveys — arguing that the state’s open records laws allow agencies to keep records from non-criminal investigations and internal deliberations private.

Without the underlying sample data, outside physicists would be hamstrung in any effort to review the DEP‘s conclusions. Almost immediately, Delaware Riverkeeper Network challenged DEP‘s decision, asking the Pennsylvania Office of Open Records to force the DEP to hand over the data. The Office of Open Records agreed with the environmental group and ordered the DEP to hand over the records. DEP appealed that decision to the Commonwealth Court. While that case was still pending, the DEP released its radioactivity study in January of this year.

Published just five days before the end of the administration of Tom Corbett, a staunch supporter of the shale gas rush, that report was accompanied by a press release headlined “DEP Study Shows There is Little Potential for Radiation Exposure from Oil and Gas Development.”

On April 10, one day after the Johns Hopkins study was published, the Commonwealth Court released its ruling. The court agreed with DEP that the records did not have to be made public because they were records from a non-criminal investigation.

Asked by DeSmog if the DEP intended to release their data in the wake of the international attention that the Johns Hopkins study drew to radon and fracking in Pennsylvania, Susan Rickens, a spokesperson for the Pennsylvania Department of Environmental Protection, said that their data had been posted online when the radioactivity study was published. But the data available online is incomplete, according to the Delaware Riverkeeper Network.

“What we did get we will base our report on but there is still information they are keeping secret,” Ms. Carluccio said.

Correlation Not Causation

Many questions remain unanswered about the connection between radon levels in people’s homes and shale drilling and fracking.

The DEP‘s research reached different conclusions from the Johns Hopkins study in part because their methodologies and focus differed, state officials say.

Ms. Rickens noted that the ties between shale drilling activity and radon levels were not clear-cut. And she offered a critique of the Johns Hopkins research.

Radon levels also rose in areas of the state where there was no drilling, like Philadelphia and the Reading region, she said. “No explanation is offered regarding the upward trend across all areas of the Commonwealth during the same time period,” she said.

The Johns Hopkins researchers have also said that their research does not prove that fracking caused radon levels to rise, but say it demonstrates a need for more in-depth analysis.

Some of the relationships between radon levels and nearby fracking were “statistically significant,” Prof. Schwartz told The Columbus Dispatch. “The higher the gas production … the higher the basement radon levels,” Prof. Schwartz added.

The Johns Hopkins researchers responded to the state’s conclusion that radon posed little risk in an article posted on Gizmodo.

“We do worry about false reassurance since they only took measurements at 34 wells, less than 1% of the wells statewide, and did not consider how two or more wells close together could be additive,” Joan A. Casey and her colleague Dr. Schwartz wrote. “In our study we sought to take into account the cumulative effect of thousands of wells drilled statewide, and at a location more relevant to health – in buildings where people live, work and play. By contrast, the state study evaluated a few point sources of radiation pollution.”

Asked if the DEP‘s earlier conclusion that the public had little to worry about from radon associated with fracking was overly broad, Ms. Rickens focused on the differing methodologies of the two reports.

“The scope of the two studies were quite different,” she said. “All of  DEP’s sampling was done outdoors.  No indoor air monitoring was performed.”

Environmentalists raised other objections to the state’s methodologies, and in particular to the failure to release their underlying data.

“For instance, some of the ‘peer reviewers’ with whom PADEP shared the report were not given any data,” Ms. Carluccio said.

“Essentially, that means PA is allowed to conduct a ‘peer reviewed’ study with a much lower threshold than any legitimate scientific publication and without releasing any data, presenting an even greater lack of accountability and transparency in a situation where it is crucially needed.”

Risk From Radon?

There is little dispute that the Marcellus shale, which spans several Eastern states, is unusually radioactive. The oil and gas industry makes use of that radioactivity — 20 times higher than background — to pinpoint the Marcellus shale’s location underground.

The debate centers on the health hazards posed to when the drilling industry disturbs the radioactive shale layer — what, realistically, is the harm that these naturally occurring radioactive elements can do to workers, locals, and the general public? Much of the answer to that question depends on whether traces of radioactive materials find their way into the water people drink or the air people breathe.

As a result, one of the most hazardous radioactive elements associated with the Marcellus shale is radon — a colorless, odorless gas that is the leading cause of lung cancer among non-smokers in the U.S.

Some physicists worry that enough radon could be mixed in with natural gas from the Marcellus shale to make using shale gas as a fuel a potential cancer risk.

“Radon is an inert radioactive gas. This means it does not react chemically with other elements,” explained Marvin Resnikoff, Senior Associate at Radioactive Waste Management Associates, in a 2012 paper on radon in the Marcellus. “Whatever radon is in the pipeline and is delivered to homes is released to the home environment from unvented kitchen stoves and space heaters. The radon is not oxidized and is not made benign or non-radioactive in the burning process. “

The Johns Hopkins researchers warned that it is too early to tell conclusively whether shale gas had anything to do with the radon levels found in Pennsylvania homes, noting that their data did not show whether people with high radon levels used natural gas appliances in their homes.

“Our study can be improved by including information that was not available for our analysis, such as whether natural gas is used for heating and cooking, whether there is any radon remediation in the building, and general condition of the building foundation,” Dr. Schwartz said in a statement. “But these next studies should be done because the number of drilled wells is continuing to increase and the possible problem identified by our study is not going away.”

While that research continues, public health advocates have called for a cautious approach.

“There are a tremendous number of poorly understood and potentially serious health risks associated with fracking, one of which is exposure to radioactivity,” Aaron Bernstein, a pediatrician and associate director of the Center for Health and the Global Environment at the Harvard H.T. Chan School of Public Health told USA Today. “We simply do not have anything close to adequate safeguards for people’s health.”

Photo Credit: Natural gas flame, via Shutterstock.