In February, we reported on the Ninth Circuit’s decision in Nelson v. Matrixx Initiatives, Inc.that granted defendant’s motion for summary judgment based on plaintiff’s failure to prove specific causation through expert witness testimony in a toxic tort case.   See article.   Last week, the Seventh Circuit reinforced that holding, clarifying that an expert witness wasnecessary to establish specific causation in a negligence action brought against amusement park owners alleging plaintiff developed chronic asthma and reactive airways dysfunction syndrome (RADS) from inhaling chlorine gas at the park.  Higgins v. Koch Dev. Corp., No. 14-2207, 2015 WL 4394895 (7th Cir. July 20, 2015). 

In Higgins, the plaintiff visited an amusement park where a filter pump malfunctioned and released a cloud of chlorine gas into the air.  Plaintiff inhaled lingering chemical fumes and visited a hospital the same day for treatment.   A year later, Plaintiff consulted his primary care physician who referred him to a pulmonologist.  Nearly a year after that initial doctor’s visit, the plaintiff filed this negligence action against the amusement park owners alleging he developed chronic asthma as a result of exposure to the chlorine gas.

To prove his negligence claim, Higgins sought to designate the doctor who examined him for purposes of the litigation as his causation expert.  The district court disqualified the doctor’s testimony for failure to establish a reliable methodology.  In opposition to defendant’s subsequent motion for summary judgment, and lacking a causation expert, Higgins sought to persuade the district court that expert testimony regarding causation was unnecessary to prove his cause of action for negligence.  The district court disagreed finding a proper causation expert essential to prove his negligence claim.

On appeal, Higgins argued that no expert testimony was required to prove specific causation, citing to a prior Seventh Circuit decision that held “[e]xpert testimony is unnecessary in cases where a layperson can understand what caused the injury.”  Meyers v. III. Cent. R.R. Co., 629 F.3d 639, 643 (7th Cir. 2010) (holding that “when a plaintiff suffers from a broken leg or a gash when hit by a vehicle, he doesn’t need to produce expert testimony”).  The Seventh Circuit disagreed with plaintiff’s analogizing his injury to a case where a layperson could understand what caused the injury without the aid of expert testimony.  Higgins, 2015 WL 4394895 at *3 (“[A] typical layperson does not possess the requisite knowledge to draw a causative line, without the assistance of a medical expert, between a brief encounter with chlorine gas and the onset of . . . asthma.”).

The Seventh Circuit clarified that questions of “medical causation of a particular injury” are “questions of science” and therefore necessarily depend on expert testimony.  Id. at *4.  Furthermore, the Higgins Court suggests in dicta several other factors weighing in favor of requiring expert testimony.

First, the necessity of expert testimony to prove specific causation may depend on the time period between the occurrence of the alleged cause and the resulting harm.   In Higgins, the Seventh Circuit pointed out that it is improper for a plaintiff to ask a jury to make the causative connection between inhalation of gas and a chronic condition “after some unspecified interval of time following the release of the gas.”  Id.  By contrast, in the Court’s view, the causative connection is far more apparent where a plaintiff’s symptoms present immediately.

Second, courts appear more likely to require expert testimony—as in Higgins—where the plaintiff alleging negligence seeks damages for permanent, chronic conditions as opposed to symptoms.  The reason for this distinction is that a jury is less equipped, absent the aid of expert testimony, to determine the origin of a chronic condition than an immediate harm suffered that presents as typical symptoms (e.g. swollen eyes or dizziness resulting from prolonged exposure to paint fumes).  The Seventh Circuit warned that allowing a jury to decide a case involving an allegation that brief exposure to a chemical caused a “permanent and debilitating lung dysfunction” without an expert would necessarily rely on “the logical fallacy post hoc ergo propter hoc (the fallacy of saying that because effect A happened at some point after alleged cause B, the alleged cause was the actual cause).”

Last, and related to the two forgoing, expert testimony regarding specific causation is particularly relevant where evidence exists of reasonable—and even probable—alternative causes of the alleged harm.  For example, in Higgins, the plaintiff’s treating physician testified that Higgins was obese and that obesity affects lung volume.  In its opinion, the Court intimates that Plaintiff’s obesity—and not his inhalation of chlorine gas—may have caused, or at least contributed to, his developing chronic asthma.  Id. at *3.  The Court emphasized that “[g]iven so much uncertainty, there is no question that a layperson is incapable of scientifically determining specific causation here without the assistance of an expert.”  Id.

Overall, Higgins provides good precedent for defendants hoping to prevail on summary judgment where plaintiffs lack reliable expert testimony on specific causation.