A new study of a radioactive, carcinogenic gas has grabbed the attention of news outlets and both pro and anti-fracking groups alike. The study published earlier this month says increases of radon gas in people’s homes in Pennsylvania coincide with the horizontal drilling boom. Some geological researchers in the region are skeptical while others aren’t at all surprised.
42 percent of radon readings in Pennsylvania surpass what the U.S. government considers safe, according to a report out of Johns Hopkins Bloomberg School of Public Health. And those levels have been on the rise since 2004, which is when horizontal drilling for natural gas wells took off in the state. One of the report’s authors, Joan Casey, says the two could be connected.
“Given the fact that the geology in PA contains a lot of uranium, which is a precursor to radon gas, and the fact that this industry opens up a lot of different pathways in the ground,” Casey said, “we thought that there was a possibility that the industry might be influencing indoor radon levels.”
Radon is the number one cause of lung cancer among non-smokers, according to estimates by the US Environmental Protection Agency; it’s responsible for about 21,000 lung cancer deaths every year. Casey and her colleagues analyzed 860,000 indoor radon measurements collected by the Pennsylvania Department of Environment Protection between 1989 and 2013. Researchers were hoping to gauge if there’s been a cumulative effect from the drilling and gas production of 7,469 horizontal wells. They found that between 1989 and 2004, radon levels fluctuated quite a bit, but in 2004, data indicates that radon levels began increasing state-wide.
“And the interesting thing was that in the counties that had more unconventional natural gas development, the levels of radon indoors increased more quickly than places that didn’t have that development,” Casey said.
In her report, scenarios are laid out that could possibly account for some of the increases.
- Radon gas diffuses naturally from soil under buildings.
- Radon gas can be dissolve into water (the report says you are 21 percent more likely to have a radon problem if you have groundwater in your house).
- Natural gas used to heat homes can also be laced with radon if it comes from Marcellus rock formations, which doesn’t burn off.
- There’s also the threat of radon pollution from drilling operations and leaks from various gas transmission avenues.
“The main way that radon gets into homes is from diffusing from the soil underneath the buildings and getting into the basements. And then if the basement is pretty tightly sealed the radon gets trapped inside. And that is how people get exposed.”
But some geologists in West Virginia think the connection between drilling activity and increases in radon is only distantly related, if at all.
“The numbers are probably right. The descriptive part is right. The inferential part is dead wrong, in my opinion,” said Tim Carr, a professor of geology at West Virginia University.
Carr is also the head of a major horizontal gas drilling study that’s just gotten underway in Morgantown. He’s says the idea that the process of horizontal drilling is somehow responsible for increases in household radon is highly unlikely.
Carr says other factors, many of which are outlined in the Pennsylvania report, are more likely to explain the increases in radon.
“The state of Pennsylvania started a program to better insulate houses in the early 2000s. Insulate your house better and [radon] is going to go up. Electric consumption was steadily increasing because everybody is getting more computers and flat screen TVs, and then it went flat.”
Carr attributes both electricity trends and increases in radon detection to better-insulated homes. Better insulation means gas has nowhere to go and can build up to dangerous levels.
He says if the natural gas drilling boom has had an effect, it’s been an economic one. Counties with Marcellus shale drilling have seen increases in income, Carr said.
“Radon is related to your income because you build a better house. And I’ve seen it. I’ve been in Greene County and I’ve seen the abandoned trailer with a brand new house next to it.”
But not all geologists agree with Carr that horizontal drilling isn’t at all likely to produce radon pollution.
Pamela Dodds is a hydrogeologist who is very concerned about Marcellus shale drilling because of the radioactive elements present in the shale.
She points to a recent study of 34 gas wells in Pennsylvania conducted by the state’s DEP. The agency concluded that there’s no concern about exposure to radioactive elements...
“But when I looked at their actual results, I was concerned,” Dodds said. “They pointed out that there might be as much as 7 pCi per liter underneath homes nearby those wells and that the conclusion was that it was caused by the gas accumulating underneath those homes.”
The EPA says any home with measurements of 4 pCi per liter needs to be mitigated to avoid health risks associated with exposure.
Radon has a half-life of about four days. So the only significant threat would be posed by continuous, unmitigated sources. But both the Pennsylvania DEP and the authors of the recent indoor radon levels report from Johns Hopkins say technologically enhanced naturally occurring radioactive materials is a subject that needs more research.
When asked if there are any plans in the works to study this subject in Morgantown during the drilling that is planned for later this year, Tim Carr said he had not considered it, but that it wouldn’t be too difficult or expensive. There are no sure plans, however, for that research at this point.