In the Paraquat Products Liability multidistrict litigation, more than 5,000 individual plaintiffs allege that they developed Parkinson’s disease as a result of their exposure to paraquat, a widely used, U.S. EPA-regulated herbicide. The cases have been consolidated for multidistrict pretrial proceedings in the U.S. District Court for the Southern District of Illinois.
In four trial selection (i.e., bellwether) cases, the defendants, Syngenta Crop Protection, LLC and Chevron U.S.A., Inc., moved to exclude the testimony of plaintiffs’ sole expert on the issue of general causation. Following submission of briefs, expert reports, and deposition transcripts, and after conducting a four-day “Daubert” hearing, Chief Judge Nancy J. Rosenstengel granted the motion to exclude on the ground that the proferred testimony was unreliable under Federal Rule of Evidence 702 (Testimony by Expert Witnesses). Because the exclusion of the general causation testimony is fatal to the plaintiffs’ claims, the court dismissed their suits.
ALF has filed an amicus brief in support of the Defendants-Appellees and affirmance of the district court’s expert testimony exclusion order. The brief was authored by Eric G. Lasker and Elyse A. Shimada of Hollingsworth LLP and ALF Executive Vice President & General Counsel, Lawrence S. Ebner.
ALF’s Amicus Brief
ALF’s amicus brief endeavors to enhance the Court’s perspective on Rule 702 by providing additional background on the genesis, purpose, and adoption of the Rule 702 Amendments that took effect on December 1, 2023, and by discussing the relationship between unreliable scientific testimony and due process.
The brief explains that the 2023 Amendments reflect concerns expressed by the U.S. Judicial Conference’s Advisory Committee on Evidence Rules that district judges were not fulfilling their expert testimony gatekeeping role by allowing juries to decide whether an expert’s testimony satisfies Rule 702’s reliability criteria. To reinforce district judges’ gatekeeping duty, the 2023 Amendments clarify two important aspects of the Rule:
First, the Advisory Committee’s Notes to the 2023 Amendments indicate that the revised Rule is intended to “clarify and emphasize that expert testimony may not be admitted unless the proponent demonstrates to the court that it is more likely than not that the proffered testimony meets the admissibility requirements set forth in the rule.”
Second, the Amendments clarify “that each expert opinion must stay within the bounds of what can be concluded from a reliable application of the expert’s basis and methodology.”
These textual clarifications to Rule 702 underscore a district court judge’s expert testimony gatekeeping role. The amicus brief explains that where—unlike in the Paraquat litigation—a district court fails to act as gatekeeper by allowing a jury to “weigh” the reliability of expert testimony, the defendant can be deprived of a fair trial and due process of law.