Appeals Court Urged To Reinstate Paraquat Lawsuits Previously Set for Bellwether Trials

Expert witnesses that would have testified about the link between Paraquat and Parkinson’s disease were held to an unreasonably high standard by the trial judge, plaintiffs’ attorneys argued.

The Seventh Circuit Court of Appeals is weighing whether to reinstate four Paraquat lawsuits, which were once slated to be the first federal bellwether trials over Parkinson’s disease risks linked to the controversial weedkiller, before they were dismissed by the federal trial judge last year, after proposed expert witnesses were barred from testifying.

The lawsuits are part of ongoing litigation over Paraquat, which was first marketed under the brand name Gramoxone in the 1960s, and has been widely used throughout the agricultural industry for decades.

Syngenta and Chevron now face more than 5,800 product liability lawsuits in the federal court system, each involving claims that the manufacturer failed to adequately disclose the link between the use of Paraquat and an increased risk of developing Parkinson’s disease.

Given common questions of fact and law, all federal Paraquat lawsuits over Parkinson’s disease have been centralized as part of a multidistrict litigaiton (MDL) before U.S. District Judge Nancy Rosenstengel in the Southern District of Illinois since June 2021, where the parties have been preparing small groups of representative claims for early “bellwether” trials to gauge how juries may respond to certain evidence that will be repeated throughout the claims.

Judge Rosenstengal established the “bellwether” process early in the litigation, but ended up dismissing the first batch of potential Paraquat bellwether lawsuits last year.

In advance of trial, the Court issued a controversial ruling excluding the plaintiffs’ expert witness from testifying at trial. As a result of the decision, it left these four plaintiffs without an ability to prove to a jury that they developed Parkinson’s disease from Paraquat.

Paraquat Appeal Sought by Initial Bellwether Plaintiffs

Although Judge Rosenstengal selected 10 new Paraquat bellwether candidates in August 2024, which are now being fast-tracked for trial involving different expert witnesses, plaintiffs from the original selections filed an appeal to have their cases reinstated.

On Wednesday, the Seventh Circuit heard arguments, at which the plaintiffs indicated that Judge Rosenstengel held their expert witnesses to too high a standard. In addition, plaintiffs argued that the decision came at the wrong time in the litigation, and that the testimony was cherry picked apart with criticisms that fell outside of court precedents.

Attorneys argued that the disagreement between the parties over the reliability or sufficiency of the expert witness testimony should have been decided by a jury, but their cases were improperly dismissed.

The manufacturers maintain that there has been no peer-reviewed research that makes a causal link between Paraquat and Parkinson’s disease, and continue to dispute the underlying claims raised in the litigation.

New Paraquat Lawsuit Bellwether Selections and Trial Dates

As the appeal plays out, Judge Rosenstengal announced late last month that full case-specific discovery will be conducted on another six Paraquat lawsuits from the second batch of potential bellwether claims, which replaced those thrown out last April.

The order identified three of the bellwether lawsuits, including complaints filed by Donald Tucker, Paul Scibilia and Marshall Bork, as candidates for the first bellwether trial, which will begin on October 14, 2025. The three other lawsuits, including claims filed by Michael Peek, Russel Okerlund and Douglas Malish, will be eligible for the second bellwether trial, slated to begin on April 6, 2026.

While the outcome of these trials will not have any binding impact on other plaintiffs, they are likely to have a substantial influence on average Paraquat settlement amounts the manufacturers may offer to avoid each individual claim being remanded back to U.S. District Courts nationwide for separate trial dates in the coming years.