For years, plaintiffs in product liability and toxic tort cases have viewed Pennsylvania's state court system as a favorable forum. Over the past year and a half, however, the Pennsylvania appellate courts have issued decisions signaling an effort to bring state law in line with other jurisdictions. The Superior Court’s decision last week in Snizavich v. Rohm & Haas Co. continues that trend.

Snizavich held that an expert’s testimony is admissible only if it points to “scientific authority?whether facts, empirical studies, or the expert’s own research?that the expert has applied to the facts at hand and which supports the expert’s ultimate conclusion.” In other words, courts must ensure that each expert opinion “reflects more than mere personal belief.”

In Snizavich, the plaintiff alleged that her deceased husband was exposed to chemicals while working as a contractor at a Spring House, Pennsylvania, worksite and that he later died of brain cancer caused by such exposure. The plaintiff submitted an expert report from a medical doctor who reviewed nine documents?eight of which dealt with the decedent’s medical and work history.

The ninth document was a 2010 University of Minnesota report that purportedly found statistically higher brain cancer rates among individuals who worked at the Spring House site but was inconclusive as to the chemicals on site causing brain cancer. Despite the inconclusive results, the expert in Snizavich concluded that the Spring House chemical exposure caused the decedent’s brain cancer. The court granted the defendant’s motion to preclude the expert’s testimony under Frye v. United States.

On appeal, the Superior Court identified the specific issue before it as “whether there is any minimal threshold that expert testimony must meet in demonstrating that the proffered testimony reflects the application of the expert’s expertise, as opposed to simply being a lay opinion offered by an expert.” The court agreed with the trial court that the expert’s report was “nothing more than a logical post hoc ergo propter hoc fallacy?decedent worked at Spring House, then decedent died of brain cancer, therefore working at Spring House caused the decedent to die of cancer.”

In summing up the expert standard, the Superior Court explained that expert testimony as to a causal relationship “may be admissible, even if based solely on the expert’s review of medical records and his experience and expertise in the applicable medical field, when the expert can point to some scientific authority that supports the causal connection.”

The Snizavich opinion should provide some comfort to corporate defendants in Pennsylvania litigation facing the all-too-familiar scenario of a plaintiff’s expert opining that, because a plaintiff was exposed to a chemical attributable to the defendant and later became ill or died, his illness or death must have been caused by that exposure. This continues a trend toward requiring increased scrutiny of expert testimony in Pennsylvania, a trend that began in earnest with Betz v. Pneumo Abex and Howard ex rel. Estate of Ravert v. A.W. Chesterton Co., in which the Supreme Court of Pennsylvania put a stop to the use of boilerplate expert testimony that each and every fiber of inhaled asbestos can be a substantial contributing factor to asbestos-related diseases?diseases that are by nature dose-responsive?finding that such opinions fail under Frye due in part to “large analytical gaps.”

With Snizavich, Betz, and Howard, defendants in Pennsylvania product liability and toxic tort cases are better equipped to challenge expert reports, while plaintiffs may begin more seriously considering non-Pennsylvania forums when given the opportunity in such cases.