Babies born to mothers living within two-thirds of a mile from a fracking well site see a 25 percent increase in the probability of significantly low birth weight, a condition linked to other health problems later in life, according to a new study. The research adds to a growing body of scientific work that links the controversial extraction process with adverse effects on the environment and people.

Based on an analysis of more than 1.1 million births in Pennsylvania between 2004 and 2013, the researchers found that babies born to mothers who lived within 1 kilometer, or 0.64 miles, of a fracking well weighed, on average, 1.38 ounces less than babies born to women whose pregnancies occurred 3 kilometers or more from a fracking site.

Low birth weight is a risk factor for numerous negative outcomes, including infant mortality, attention deficit hyperactivity disorder, asthma, lower test scores, lower schooling attainment, lower earnings, and higher rates of social welfare program participation, the researchers noted.

The Princeton University, University of Chicago, and University of California-Los Angeles researchers found little evidence of health effects at distances beyond 3 kilometers, suggesting that health impacts of fracking are highly local. The study, “Hydraulic Fracturing and Infant Health: New Evidence from Pennsylvania,” was published Wednesday in the journal Science Advances.


“Given the growing evidence that pollution affects babies in utero, it should not be surprising that fracking, which is a heavy industrial activity, has negative effects on infants,” co-author Janet Currie, the Henry Putnam Professor of Economics and Public Affairs at Princeton University, said in a statement.

Energy In Depth, an industry advocacy group started by the Independent Petroleum Association of America in 2009, said it views the study as flawed. Researchers found birth weight anomalies that they link to fracking but then admit the sampled population would be expected to have similar effects even without fracking, the industry group said in a blog post published Wednesday.

“The authors admit that the study was only exploring ‘potential’ pollution, not ‘actual exposure,’ and even said that such pathways are ‘not known with certainty.’ Instead, the authors relied on a simple spatial correlation to suggest that the closer mothers live to production sites, the more likely they are to have babies with lower birth weights,” Energy In Depth noted.

In a 2014 study that examined babies born from 1996 to 2009 in rural Colorado locations, researchers found that women who lived close to natural gas wells were more likely to have children born with a variety of defects, from oral clefts to heart issues. The researchers, however, were unable to include data on maternal health, prenatal care, genetics, and other factors that have been shown to increase the risk of birth defects.

Lisa McKenzie, one of the lead authors of the Colorado study, said there was value to the work. “What I think this is telling us is that we need to do more research to tease out what is happening and to see if these early studies hold up when we do more rigorous research,” she told ProPublica.


Another study, published in August 2016, found that fracking in Pennsylvania may be associated with migraines, fatigue, and sinusitis. The study was led by John Hopkins University researchers who chose to evaluate these health conditions due to their high prevalence, large economic costs, and possible link to environmental risk factors like chemical toxicity or odors.

Also last year, Environment America released a report that found children are more sensitive than healthy adults to chemicals and particles in the air, but across the United States at least 650,000 students from kindergarten to high school spend their days within a mile of a fracking facility. In West Virginia, for example, 8 percent of K-12 students spend their days less than a mile from fracking operations. Fully 10 percent of nursing homes are within one mile of a fracked well.

For the new study, the researchers were able to compare babies born to the same woman. Of the records examined, 594 of the babies born within 1 kilometer of a fracked well had a sibling who was born before fracking began. The data allowed the researchers to compare the birth weights among children born to the same mother. A larger group, 3,538 infants, lived between 2 and 3 kilometers from a well and had an unexposed sibling.

“This study adds to the existing scientific literature that tells us there are serious public health consequences linked to fracking,” Food & Water Watch Executive Director Wenonah Hauter said Wednesday in a statement. “Unfortunately, Governor Wolf wants to take Pennsylvania in the opposite direction, by encouraging new drilling and expanding fossil fuel operations.”

Pennsylvania Gov. Tom Wolf (D) has been a strong supporter of shale gas drilling in the state since taking office in January 2015. Pennsylvania’s natural gas production reached a new high of 15 billion cubic feet per day in October, an increase of 25 percent from October 2016 levels and an increase of 80 percent from January 2013. Currently, Pennsylvania accounts for 19 percent of total U.S. natural gas production, according to the U.S. Energy Information Administration.