Written with Janet Currie of Princeton and Kathrine Meckel of UCLA.

Hydraulic fracturing, or fracking, is perhaps the most important energy discovery in the last half century. As a result of fracking, U.S. production of oil and natural gas has increased dramatically. This increase has abruptly lowered energy prices, strengthened energy security and even lowered air pollution and carbon dioxide emissions by displacing coal in electricity generation. The lower energy prices have meant more money in the pockets of American families and businesses. And the lower emissions are certainly good news for our health with large reductions in air pollution dispersed across the country and, at least for the near term, our climate.

Whether or not we as a society continue to gain from the broad benefits of fracking rests on the shoulders of the local communities where drilling takes place, or could take place. These communities must determine if the local benefits exceed the local costs, a calculation that requires a lot of information to be done well. Over the past year, we have been part of two research efforts that have shed light on what’s at stake in the choices communities are making.

On the benefits side, fracking increases economic activity, employment, income and housing prices. But, it also brings more truck traffic, increases in crime and potential health impacts possibly due to air and/or water pollution. In some recent work, we’ve added it all up. We discovered that for the average household living in a community where fracking takes place the benefits exceed the costs—indeed, it is worth about $2,000 per year to them. That calculation of $2,000 per year is based on people’s current understanding of the health impacts at the time of our study. If people’s understanding of the health impacts were to change, it is likely that this would alter the net benefits of allowing fracking.

Since health is such a critical factor, we decided to dig in further by looking at the health of those born near fracking sites. Our findings, published recently in the journal Science Advances, present the first large-scale peer-reviewed evidence of a link between hydraulic fracturing and health.

Specifically, we found that babies born within 3 kilometers, about 2 miles, of a fracking site are more likely to suffer from poor health. The largest impacts were to babies born within 1 kilometer, about a half mile, of a site, with those babies being 25% more likely to be born at a low birth weight (i.e., less than 5.5 pounds). Equally important, those babies born to mothers living further than 3 kilometers didn’t show any health impacts, indicating that the health impacts are highly localized. Out of the nearly 4 million babies born in the United States each year, back of the envelop calculations suggest that about 30,000 of them are born within a kilometer of a fracking site and another 100,000 are born between 1 and 3 kilometers away.

Our findings are based on a massive amount of data: 9 years’ worth of birth records from throughout Pennsylvania, totaling 1.1 million births. These records included information about the infant’s health at birth, where the mother lived, and detailed demographic information about the mother such as race, education and marital status. We then combined this data with a list of all fractured wells in Pennsylvania through 2014, which included 7,757 wells.

One big question that naturally arises from this kind of work is whether the analysis controls for other factors that might contribute to low birth weight such as socio-economic or behavioral factors. For example, mothers who live nearby active fracking site are younger, less likely to have been married at the time of the birth, and less educated—characteristics that might lead to worse infant health outcomes.

We account for these differences by comparing infants born to mothers living up to 3 kilometers away from a site to those living between 3 and 15 kilometers, both before and after fracking began. Conducting the analysis this way does a great deal to control for these other factors that affect infant health. Specifically, any explanation besides fracking activity would need to involve differential changes in the determinants of health among infants born to mothers living within 3 kilometers of a fracking site, relative to infants born to mothers living 3-15 kilometers away, after fracking was initiated. In other words, at the onset of fracking, mothers living closer to wells would have to suddenly become poorer or use more  alcohol or eat less healthy, and they would have to do so more than mothers living farther away. We can’t rule out this possibility, but our investigations failed to turn up credible evidence for such changes in the data.

Nevertheless, we further probed the health of babies born after fracking, comparing it to that of their siblings born to the same mother before fracking. This test’s appeal is that many of the concerns about unobserved differences in determinants of infant health are much less likely to be relevant when comparing siblings that share the same mother. Here again, the data shows that the initiation of fracking is associated with an increase in the probability of low birth weight. The limitation of this test is that it is very demanding of the data, so these results are not significant on their own, but they provide a compelling validation of the main results.

While our study provides a link to fracking activities and poorer infant health, it doesn’t tell us what aspects of fracking lead to those poorer health outcomes. Because many people in the study got their water from municipal sources not close to fracking sites, we suspect water contamination isn’t to blame. The most plausible explanation appears to be localized air pollution caused by the increased truck traffic, the diesel generators powering the sites, or perhaps other emissions, but the evidence on the cause is not decisive. Indeed, future work exploring the mechanism is warranted. Another important area for future research is to explore whether fracking affects health at other ages. We hope that our paper will open up these lines of inquiry.

Fracking has upended the American energy system. It has brought substantial benefits to the nation in terms of lower energy prices, greater energy security, reduced air pollution, and fewer carbon emissions (although its long-run impact on carbon emissions is less clear). Our research shows that there are also health and other costs to local communities where fracking takes places.

As governments and communities with shale deposits in the United States and around the world continue to grapple with whether to allow fracking, it is vital that they have the facts on its impacts. This is the only way to ensure that we get fracking’s benefits and minimize its costs.

Continue Reading at Forbes…

Areas of Focus: Hydraulic Fracturing
Hydraulic Fracturing
Hydraulic fracturing is perhaps the most important innovation in the energy system in the last half century, but nearby communities are concerned about its potential effects on water quality, public...