Births and fractured wells in Pennsylvania between 2004 and 2013.| Currie et al. Sci. Adv. 2017;3:e1603021
Infants born to mothers living about 2 miles or 3 kilometers from a hydraulic fracturing site are more likely to have a low birth weight, according to a study published December 12 in Science Advances.
At distances, farther from these “fracking” wells, researchers found no evidence of compromised infant health.
The researchers did not determine which factors related to fracking might have an impact on birth weight, potentially including air and water pollution, chemicals used at the drilling sites, or an increase in motor traffic. “This is a critical area for future research,” said co-author Katherine Meckel, an assistant professor at University of California, Los Angeles, “because it can help identify ways to mitigate or even erase the health effects, without causing communities to lose out on the local economic benefits of hydraulic fracturing.
Michael Greenstone, the Milton Friedman Professor in Economics and director of the Energy Policy Institute at the University of Chicago and study coauthor said, “This study provides the first large-scale, peer-reviewed evidence of a link between hydraulic fracturing activities and our health, specifically the health of babies.”
The most significant health impacts Greenstone and colleagues discovered after analyzing a decade’s worth of data were to babies born within about a half-mile of an active well. These infants were 25% more likely to be born weighing fewer than 5.5 pounds, a birth weight with known risks for infant mortality, ADHD and asthma.
Out of the nearly 4 million babies born in the United States each year, about 29,000 of them are born within about a half-mile of a fracking site, informal estimates suggest, while another 95,500 are born about a half to 2 miles away.
Throughout the United States, the application of hydraulic fracturing to develop oil and natural gas resources has led to an increase in U.S. energy production. It has also generated benefits including lower energy prices and stronger energy security.
But while some see the new energy boom from fracking as a benefit to the local economy, others fear the potential health consequences. Pinpointing health impacts of hydraulic fracturing – for example, those related to potentially toxic chemicals used in the water that’s injected deep into the rock to create small fractures – has been challenging.
“It’s hard to identify the health effects of hydraulic fracturing because the communities where it takes place are often poorer and more rural, with less educated residents who are more likely to smoke and may also be more likely to have other health conditions,” said co-author Janet Currie, the Henry Putnam Professor of Economics and Policy Affairs at Princeton University, and the director of Princeton's Center for Health and Wellbeing. “So, if people in these communities have worse health, it is often not clear whether that is because they are likely to be sicker from the start, or whether there is an effect of fracturing.”
Determining the possible health impacts to newborns, who are especially susceptible to health shocks, has been a critical goal. To date, several studies evaluating influences on infant health in other contexts have found that air pollution can be harmful, through maternal exposure before birth.
Greenstone and colleagues analyzed records of more than 1.1 million births in Pennsylvania from 2004 to 2013. They compared the birth weights of babies born to mothers living within 1, 2 or 3 kilometers of fracking wells – both before and after drilling began.
To be more certain of identifying health influences specifically related to well proximity, the researchers compared records of siblings born close enough to be exposed to fracking in utero with those who were not.
While the greatest risk of low birth weight was to infants born to mothers living within about a half mile of an active well, infants born to mothers living half a mile to 2 miles from a site were also more likely to exhibit low birthweight, though to a lesser frequency. In contrast, the study found no evidence of impacts on infant health among babies born to mothers living farther than about 2 miles from a well.
These results suggest that hydraulic fracturing does have an impact on infant health, but only at a highly localized level.
“Efforts to mitigate effects from fracking should focus on the relatively small number of people who live quite close to fracking sites,” said Currie. Some first steps toward mitigation, she added, might be to institute monitoring of sites that have residents nearby, so that people could better understand their exposure to chemicals used in the fracking process. Another option might be to assist people in moving, Currie said, or to test water in drinking wells for fracking chemicals.
“Ultimately, our study suggests that it would be best if people did not live very close to wells,” she added. “Zoning would be one way to accomplish this, as would prohibiting fracking within a radius of populated areas.”
Despite the concerns she and colleagues have outlined, they emphasize that hydraulic fracturing is providing numerous benefits, including reducing greenhouse gas emissions by displacing coal in electricity generation. This in turn should lead to health improvements, they say.
“[In individual communities], a rational discussion of fracking will involve setting the costs against the benefits and trying to determine how we can reduce the costs so that one person’s gain is not another’s loss,” said Currie.