Something’s going on in Pennsylvania.
After examining more than 860,000 records, Johns Hopkins Bloomberg School of Public Health researchers discovered that radon levels in Pennsylvania homes have been rising since 2004. Today, 42 percent of readings are beyond what the U.S. government considers safe, according to study data.
Radon, an odorless, radioactive gas, is considered the second-leading cause of lung cancer in the world after smoking. High levels in homes have been correlated with increased risk of lung cancer for the inhabitants. Why are so many people in Pennsylvania at risk?
Fracking, the practice of injecting high-pressure liquid into natural gas bearing rock in order to release the gas, may be to blame.
After looking at hundreds of thousands of indoor radon measurements recorded in the Pennsylvania Department of Environmental Protection database during a period stretching from 1989 to 2013, Bloomberg School researchers discovered that buildings located in the counties where natural gas is most actively being extracted out of Marcellus shale have in the past decade seen significantly higher readings of radon compared with buildings in low-activity areas. There were no such county differences prior to 2004.
“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,” says study leader Brian S. Schwartz, MD, MS, a professor in Environmental Health Sciences at the Bloomberg School. “These findings worry us.”
Between 2005 and 2013, companies extracting natural gas using hydraulic fracturing drilled 7,469 wells in Pennsylvania. Unlike conventional wells, which are created by drilling vertically into porous zones of rock known to contain natural gas, wells using hydraulic fracturing are first drilled vertically and then horizontally. Once the “fracking” well is drilled, millions of gallons of water containing proprietary chemicals are injected under high pressure into the well, breaking up the shale and releasing the gas.
“These findings worry us.”
Brian S. Schwartz, MD, MS, Professor, Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health
Because this process disrupts such a large volume of rock in the process of releasing the natural gas, it can also release heavy metals and organic and radioactive materials such as radium-226, an element that decays into radon. The radon, which naturally occurs in gaseous form, then diffuses through the soil and finds its way into well water, the natural gas being extracted, and the air above the ground. Underground structures such as basements in residential and commercial buildings can act as “traps” for the radon, allowing it to accumulate to levels that increase the risk of lung cancer in humans occupying the buildings.
The study’s first author is Joan A. Casey, currently a Robert Wood Johnson Foundation Health & Society Scholar at the University of California-Berkeley and an alumna of the Bloomberg School where she earned her PhD in 2014. She speculates that the increased radon levels in homes and businesses could be the result of fracking releasing radium into well water, into the air near gas wells, or through the use of radium-contaminated natural gas used for cooking. She also notes that another possibility is that building techniques developed during the beginning of the 21st century have resulted in homes more tightly sealed than those in the past, allowing radon to accumulate in ways it couldn’t in older, more porous homes.
Whatever the reason, Casey believes that there’s a good chance that there’s a connection between increased fracking activity and increased radon levels. “By drilling 7,000 holes in the ground, the fracking industry may have changed the geology and created new pathways for radon to rise to the surface,” Casey says. “Now there are a lot of potential ways that fracking may be distributing and spreading radon.”
Download their article, “Predictors of Indoor Radon Concentrations in Pennsylvania 1989-2003”.