Paraquat MDL Judge To Evaluate Expert Testimony About Parkinson’s Disease Risk on August 21

Decisions made by the Paraquat judge will determine what expert witnesses will be allowed to testify before juries during the first MDL trials.

The U.S. District Judge presiding over all federal Paraquat lawsuits has laid out the schedule for a series of pretrial hearings, where the Court will evaluate the reliability of proposed expert witnesses and determine what testimony can be put before juries during early trials over the risk of Parkinson’s disease linked to the controversial herbicide.

Syngenta and Chevron currently face more than 4,300 lawsuits brought by individuals diagnosed with Parkinson’s disease after exposure to Paraquat-based weedkillers, which have been on the market since the 1960s, when the product was first marketed under the brand name Gramoxone. However, each complaint raises similar allegations, indicating that the manufacturers knew for years about the Paraquat Parkinson’s disease risks, but failed to warn farmers and agricultural users, who routinely spray, mix, transport and handle the herbicide.

In support of their claims, plaintiffs have proposed a collection of expert witnesses, which will testify about the link between Paraquat and Parkinson’s, pointing to research they believe shows that exposure to the toxic herbicide may cause the progressive neurological disease. However, the manufacturers have maintained that their product is safe, and dispute the conclusions reached by many of the experts.

Given common questions of fact and law raised in the litigation, all cases brought throughout the federal court system have been centralized as part of a Paraquat MDL (multi-district litigation) since June 2021, which is consolidated before U.S. Chief District Judge Nancy J. Rosenstengel in the Southern District of Illinois, for coordinated pretrial proceedings.

Paraquat MDL Judge to Review Expert Testimony

Early in the MDL, Judge Rosenstengel has set an aggressive schedule, which calls for the first Paraquat Parkinson’s disease lawsuit bellwether trial to begin in October 2023.

Starting on August 21, a series of Paraquat “Daubert” hearings will be held to allow the Court to consider the admissibility of each side’s proposed expert witnesses and rule on summary judgment motions. Judge Rosenstengel will evaluate the strength and reliability of the expert opinions to ensure the methodology used by each expert is scientifically sufficient to allow the testimony to be offered at trial.

After receiving briefs from the parties on their proposed Daubert motions on July 28, Judge Rosenstengel issued a case management order (PDF) that lays out how the Daubert hearings will be conducted.

After the parties submitted a list of additional experts that will be the subject of affirmative arguments, Judge Rosenstengel released a daily schedule for the Daubert hearings in a court order (PDF) issued on August 4, outlining arguments that will be presented over four consecutive days.

On the afternoon of Monday August 21, each party will be given 40 minutes to present their roadmap and summary of the arguments that will be presented to the Court. On Tuesday August 22, each party will be given two hours to take testimony from Dr. Martin Wells. This will be followed by shorter presentations on Wednesday August 23, including oral arguments on the admissibility of Dr. Wells’ testimony in the morning, followed by oral arguments regarding the admissibility of additional testimony from Dr. Dominik Alexander, Dr. Anthony Lang and Dr. Binit Shah in the afternoon. On Thursday, August 24, the Court will hear additional arguments regarding the admissibility of proffered testimony from Dr. C. Warren Olanow and Mr. Jack Housenger in the morning, followed by additional arguments in the afternoon regarding Dr. Elizabeth Anderson and Dr. Peter Spence.

The manufacturers are attempting to exclude expert witnesses from testifying entirely, which would leave plaintiffs without the required proof necessary to present their claim. However, unless the manufacturers are successful, it is expected that the first Paraquat bellwether trial will get underway on October 16, 2023.

While the outcome of the early jury trials will not have any binding impact on other plaintiffs, they are expected to greatly influence the outcomes of any Paraquat settlement negotiations. If the parties fail to reach such a settlement or other resolution to the litigation, thousands of Paraquat lawsuits could be remanded back to district courts nationwide for individual trial dates.