Last month, in an article published in the journal Science Advances, economics professors at Princeton University, the University of Chicago, and the University of California, Los Angeles attempted to link fracking to low birth weight. The study is controversial, and has been criticized since its publication.

Over the course of ten years, Janet Currie, Michael Greenstone, and Katherine Meckel, the authors of the study, analyzed 1.1 million births in Pennsylvania, where fracking is common. They concluded that living within 1 kilometer of a fracking well while pregnant increased the odds that one’s baby would be born with a low birth weight by 25%.

The study is headline-grabbing but has significant flaws. The authors concede that forces other than fracking could explain low birth weights in Pennsylvania frack zones. “[M]others whose babies are potentially exposed to nearby fracturing in utero are younger, less likely to have been married at the time of birth, and less educated—characteristics that might lead to worse infant health outcomes even in the absence of fracturing.” The authors also note that the study relies on possible exposure to fracking pollutants, not actual exposure shown through real monitoring data.

Author Michael Greenstone—again an economist, not a natural scientist—stated to the press, “This study provides the strongest large-scale evidence of a link between the pollution that stems from hydraulic fracturing activities and our health, specifically the health of babies.” His statement belies, however, his and his colleague’s failure to collect real pollution-monitoring data, the core of their work being actual human exposure to fracking pollutants. His statement also ignores the other potential causes of poor infant health in Pennsylvania frack zones.

The study begins, “The growth in unconventional gas production involving hydraulic fracturing . . . has transformed the energy landscape, reducing energy prices, decreasing conventional air pollution by displacing coal in electricity generation, disrupting international energy trading arrangements, and increasing the prospects for energy self-sufficiency for the United States.” Many have encouraged readers to glean from the article’s opening this truth and to discount the unfounded assertions made thereafter.

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