Fracking is already associated with earthquakes, contaminated groundwater and increasing levels of toxic radon, but now researchers are adding air quality and human health to the list.
The new study published in the journal Environmental Science & Technology, found that hydraulic fracturing – a technique for releasing natural gas from below-ground rock formations – emits pollutants known as PAHs (polycyclic aromatic hydrocarbons).
What’s more, people living or working near active natural gas wells may be exposed to these pollutants at higher levels than the Environmental Protection Agency (EPA) considers safe for lifetime exposure.
And these harmful levels are reportedly linked with increased risk of cancer and respiratory ailments.
“Air pollution from fracking operations may pose an under-recognized health hazard to people living near them,” study co-author Kim Anderson, an environmental chemist with Oregon State University, said in a statement.
Anderson and her colleagues collected air samples from sites near active natural gas wells in Carroll County, Ohio, over a three-week period last February. This region sits on top of the Utica formation, a deep oil- and gas-rich reef of subterranean shale, and thus is a hotspot of natural gas digging, with more than one active well site per square mile.
They placed air samplers on the properties of 23 volunteers living or working at sites ranging from right next to a gas well to a little more than three miles away.
The samplers picked up high levels of PAHs across the study area. Levels were highest closest to the wells and decreased by about 30 percent with distance.
Even the lowest levels – detected on sites more than a mile away from a well – were about 10 times higher than in a rural Michigan area with no natural gas wells.
The researchers then used a standard calculation to determine the additional cancer risk posed by airborne contaminants over a range of scenarios. For the worst-case scenario (exposure 24 hours a day over 25 years), they found that a person anywhere in the study area would be exposed at a risk level exceeding the threshold of what the EPA deems acceptable.
The highest-risk areas were those nearest the wells, whereas areas more than a mile away posed about 30 percent less risk, according to the researchers.
The team also pointed out that their findings are worst-case estimates and can’t predict the risk to any particular individual.
“Actual risk would depend heavily on exposure time, exposure frequency and proximity to a natural gas well,” Anderson said.