Recently, we posted a link to an article we published in the National Law Journal with Yvette W. Lowney of Exponent discussing causation issues in the context of fracking litigation.  In the article, we reviewed published studies and concluded that “taken together, the available literature contains no studies that definitively link measurable adverse human health effects with specific exposures from hydraulic-fracturing operations.”  We further observed that each study is different, addresses unique issues, and has its own set of strengths and limitations.  Accordingly, we cautioned that courts should not permit any particular study to serve a “one size fits all” purpose and that plaintiffs must be required to show specific causation in their particular cases.  In short, proximate cause remains a key factor in any fracking litigation and it is imperative that courts fulfill their gatekeeping function and avoid a rush to judgment merely because of heightened media scrutiny, emotion or politics.

It is against this backdrop that we note a recent study published in the journal PLOS ONE, where scientists from Columbia University and the University of Pennsylvania reviewed hospital admittance rates from 2007 to 2011 for 18 ZIP codes in three counties in northeastern Pennsylvania.  Two of the counties have seen an increase in drilling activity during that time period and the third functioned as a “control” because it had no active natural gas wells due to its proximity to the Delaware River watershed.  The study has generated attention-grabbing headlines like “New Report Links Fracking to Increased Hospitalizations” followed by articles discussing certain findings such as individuals living closer to active wells being more likely to be hospitalized for cardiovascular disease, cancer, and neurologic illnesses.

What is often left unsaid, however, is a critical point:  the study does not prove causation, i.e., that the health problems observed were actually caused by fracking.  Indeed, the University of Pennsylvania’s press release on the study acknowledges as much, stating that “the study does not prove that hydraulic fracturing actually causes these health problems” and that “the authors caution that more study is needed to determine how specific, individual toxicants or combinations may increase hospitalization rates.”  In addition, the study itself notes that “the precise cause for the increase in inpatient prevalence rates within specific medical categories remains unknown” and that “it is impossible to associate a specific toxicant exposure to an increase in a specific disease category requiring hospitalization.”

As more studies on fracking are published, and more headlines are generated, we must remain mindful of Chief Judge Richard Posner’s famous admonition: “[t]he courtroom is not the place for scientific guesswork, even of the inspired sort. Law lags science; it does not lead it.” Rosen v. Ciba-Geigy Corp., 78 F.3d 316, 319 (7th Cir. 1996).