Study suggests fracking could release radon from ground

Levels of cancer-causing radon gas in Pennsylvania homes have increased as the fracking industry has expanded, a new study shows.

The study is a preliminary "first look" into a possible connection between fracking and radon, a naturally occurring radioactive gas, says co-author Joan Casey. While the study doesn't conclusively prove that fracking releases radon from the ground, the findings are concerning, says Casey, a researcher at the University of California-Berkeley and University of California-San Francisco.

Fracking, or hydraulic fracturing, has spurred a boom in oil and natural-gas production. The fracking process blasts millions of gallons of water -- mixed with sand and chemicals -- deep underground to break apart shale deposits and release natural gas.

While supporters of fracking says it's a safe source of energy, opponents are concerned that the process could contaminate local water supplies and even contribute to earth quakes.

Authors of the new study, published today in the journal Environmental Health Perspectives, say they focused on Pennsylvania because it has one of highest residential radon levels in the country, and because the state has a huge, detailed database of home radon measures.

Pennsylvania's high radon levels stem from the type of bedrock that runs through much of the state, which contains radioactive materials such as uranium and radium, which degrade into radon, an invisible gas, Casey says.

Radon can seep into basements through cracks in a home's foundation and become trapped in homes that aren't well ventilated.

Doctors are concerned about radon because it's the second-leading cause of lung cancer, behind only tobacco, says Janice Nolen, assistant vice president of national policy at the American Lung Association. Radon causes 21,000 lung cancer deaths a year, according to the Environmental Protection Agency.

Authors analyzed more than 860,000 indoor radon measurements from Pennsylvania's database, taken from Jan. 1, 1989 to Dec. 31, 2013.

Researchers found that radon levels fluctuated from 1989 to 2004. But radon levels in the state began to rise around 2004, when fracking really took off, the study says.

Authors also noticed that radon concentrations were 21% higher in buildings with well water than in those using municipal water. Radon can dissolve in water. So it's possible that radon enters homes through showers and faucets, then spreads into the air, says study coauthor Brian Schwartz, a professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

Schwartz notes that it's possible that something other than fracking caused home radon levels to rise. For example, homes may have become more energy efficient since 2004. Although well-insulated homes save energy, they can also trap radon inside, he says.

A top industry group was unimpressed with the study. The Marcellus Shale Coalition, Pennsylvania's leading natural gas organization, provided USA TODAY with this statement:

"It's unfortunate, yet not unexpected, that some anti-shale activists continue to peddle profoundly flawed and unsubstantiated claims, such as this, based purely on hypothetic and perhaps pre-determined narrative-driven 'cause and effect' conclusions with the goal of generating fear," the statement read. "Thankfully, however, these suggestive scare tactics veiled as 'research' are easily refuted with readily available unbiased, fact-based data and independent scientific findings."

Authors of today's study acknowledge that their findings conflict with those of a January study from Pennsylvania's Department of Environmental Protection, which reported that "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."

Pennsylvania officials, however, say it's difficult to compare the two studies, because they measured radon in very different ways.

While Casey and Schwartz's paper included radon measurements from homes, the Pennsylvania state report measured radon at fracking wells, gas processing facilities, disposal sites and waste water processing facilities and other places, says the Pennsylvania Department of Environmental Protection's Ken Reisinger. The state report measured radon levels in the natural gas coming out of the ground, as well as in air near the fracking facilities. Radon levels weren't higher than expected, Reisinger says.

Reisinger questioned Casey and Schwartz' conclusion that fracking may be causing radon levels to rise. That's because their report also found rising radon levels in parts of the state with no fracking.

Casey and Schwartz say researchers should conduct more detailed studies to see if their findings can be confirmed.

Some health experts say the link between radon and fracking is worrisome.

"There are a tremendous number of poorly understood and potentially serious health risks associated with fracking, one of which is exposure to radioactivity," says 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. "We simply do not have anything close to adequate safeguards for people's health."

Fracking has been linked to a wide spectrum of health problems for Americans across the country, according to a December report by the Natural Resources Defense Council, an environmental group.

That report said Americans who live near oil and gas drilling wells are exposed to fracking-related air pollution in the form of chemicals such as benzene and formaldehyde.