Evidence Scientific Testimony: Long Term Exposure to PesticidesFrye

June 21st, 2018 by Rieders Travis in Evidence

Long Term Exposure to Pesticides and the Death of Golf Course Groundskeeper for 40 Years

Walsh v. BASF Corporation, 2018 Pa. Super. LEXIS 686 (June 20, 2018) Bowes, J.  Richard Thomas Walsh, Executor of the Estate of Thomas J. Walsh, Deceased, appeals from the October 14, 2016 order granting summary judgment in favor of Appellees, and challenges the propriety of the trial court’s order barring his experts from testifying pursuant to the standard enunciated in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). Since we conclude that the learned trial court erred in the manner in which it conducted the Frye inquiry herein, we reverse the grant of summary judgment, vacate the order precluding Mr. Walsh’s experts from testifying, and remand for further proceedings. Decedent, Thomas J. Walsh, was employed for almost forty years as a groundskeeper and golf course superintendent at several golf courses in the Pittsburgh area. During his employment, he frequently and regularly applied insecticides and fungicides on the golf courses.

Mr. Walsh died on February 2, 2009. His treating oncologist, James Rossetti, D.O., later opined that Mr. Walsh’s extensive chemical exposure, together with “the high-risk karyotype and dyspoietic features associated with [AML] raise a high degree of suspicion that such [occupational pesticide] exposure played a significant role in the development of his disease.” Executor commenced this wrongful death and survival action against the manufacturers of various pesticides that Decedent applied over the forty-year period, asserting claims in strict products liability, negligence, and breach of warranty. Summary judgment was granted in favor of the manufacturers and sellers of more than twenty-five of the allegedly defective pesticides on December 11, 2012, based on a lack of expert testimony identifying these pesticides as substantial contributing factors in Mr. Walsh’s death.

On August 5, 2013, the Bayer Defendants filed a motion to exclude Executor’s experts, epidemiologist April Zambelli-Weiner, Ph.D., and physician Nachman Brautbar, M.D., pursuant to Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). The other remaining defendants either joined Bayer’s Frye motion or filed their own. The substance of the Frye motions was that this case involved novel science, and the methodologies used by these experts were not generally accepted or conventionally applied in the relevant scientific communities.

At issue in the underlying litigation is whether Decedent’s forty-year occupational exposure to Defendants’ insecticides and fungicides, collectively pesticides, some of which contain known carcinogens and teratogens, was a substantial contributing factor in his death due to AML. The precise issue before us involves the propriety of the trial court’s ruling that Frye barred Executor’s experts from testifying as to causation.

Since the defense offered expert opinion that neither Dr. Brautbar nor Dr. Zambelli-Weiner applied the Bradford-Hill method in a generally accepted manner in reaching their conclusions, we find no abuse of discretion on the part of the trial court in conducting a Frye inquiry herein. Nonetheless, we find merit in Executor’s contention that the Frye inquiry herein was overly expansive. The court viewed its role as that of a gatekeeper, charged with “review[ing] the studies that Dr. Brautbar relies upon to determine whether they support Dr. Brautbar’s reliance[,]” and “to make sure that the articles stood for what Dr. Brautbar said that they did.”

The trial court did not expressly find that Dr. Brautbar’s manner of applying Bradford Hill was not generally accepted. Rather, the court focused on Dr. Brautbar’s reference to studies in applying those factors, and concluded that his reliance upon particular studies was not in accordance with generally accepted scientific methodology. In arriving at that conclusion, the court scrutinized the studies cited by Dr. Brautbar, assessed their scientific relevance and validity, and then arrived at its own conclusion whether the expert’s reliance upon them was scientifically acceptable. The court’s finding that Dr. Brautbar did not follow accepted methodologies in relying upon certain studies in forming his opinions as to general causation added another layer to the generally accepted methodology requirement. Furthermore, the trial court did not identify the methodology it was employing or reference testimony from scientists in the field. In short, the trial court baldly concluded, “Dr. Brautbar’s reliance on this literature to support his general causation theory is not in accordance with generally acceptable scientific methodology.” The trial court employed the same flawed approach in evaluating the sources reviewed and cited by Dr. Brautbar in support of his specific causation opinions. Notably, the defense experts did not dispute the general acceptance of Dr. Brautbar’s choice of the differential etiology methodology for determining specific causation. That method permits a medical expert to render specific causation opinions based on the scientific information available, the patient’s history, his education, training, and experience. We routinely require our experts, especially medical experts, to apply their scientific knowledge, information, and expertise to a unique set of circumstances.

Although the epidemiological studies cited by Executor’s experts did not explore whether exposure to one particular pesticide product caused AML, we reject Defendants’ contention that such specific studies were required in order to survive a Frye scrutiny. The EPA assesses the cumulative risk of pesticides that share common mechanisms of toxicity or act the same way in the body.

The general scientific principle underlying the opinions of Dr. Zambelli-Weiner and Dr. Brautbar is that long-term exposure to pesticides can cause or increase the risk of leukemia, and specifically AML. The literature and studies, in the aggregate, support the general acceptance of that principle. In addition, medical science in the form of cytogenetic studies linking changes in certain chromosomes with exposure to chemicals supports a causal link. Dr. Brautbar used the differential diagnosis theory, which is generally accepted in the scientific community, to arrive at his opinion that long-term pesticide exposure was the cause of Decedent’s AML. See In re Paoli R.R. Yard PCB Litig., 35 F.3d 717, 756 (3d Cir. 1994) (affirming for purposes of the Frye prong of the Daubert inquiry, that differential diagnosis is widely accepted technique, subjected to peer review, used by the medical community to rule in or out alternative causes).

Orders vacated and case remanded for further proceedings.