The federal judge ruled that a crucial expert witness cannot give testimony in court for lawsuits alleging that Syngenta's herbicide paraquat leads to Parkinson's disease. As a result, the first four cases involving the product scheduled for trial have been dismissed.

The legal representatives of farmworkers taking legal action against Syngenta and Chevron, which previously sold Paraquat before 1986, wanted Cornell University professor Martin Wells to testify that being exposed to the chemical at work can lead to the disease. U.S. District Judge Rosenstengel decided the trials could not proceed without this testimony.
Judge Rosenstengel’s decision has no immediate bearing on the thousands of other cases consolidated in her East St. Louis, Illinois courtroom. However, she has instructed the plaintiffs’ legal team and the defendant companies to recommend an alternative set of cases for trial, allowing the plaintiffs to present a new expert witness.
By disallowing Wells from taking the stand, Rosenstengel criticized his methodology, stating that it selectively presented data in an unscientific manner. Furthermore, she expressed concern that his conclusions had not been corroborated or verified through rigorous, unbiased scientific scrutiny outside of this legal case, which raises suspicions about their validity.
The main lawyers representing the plaintiffs in the lawsuit, including Khaldoun Baghdadi from Walkup, Melodia, Kelly & Schoenberger; Les from Levin, Papantonio, Rafferty, Proctor, Buchanan, O’Brien; and Peter Flowers from Meyers & Flowers, released a statement together stating their intention to challenge the decision made and to move a group of cases in court.
“We remain committed to pursuing justice for the thousands of U.S. farmworkers who have been afflicted with a chronic and devastating illness as a result of their contact with paraquat, and will press forward with these legal cases on their behalf.”
The companies have rejected the claim that Paraquat is responsible for causing Parkinson’s disease, a degenerative condition of the nervous system characterized by tremors and mobility issues.
Chevron stated that the ruling confirmed that, after numerous studies carried out in the last six decades, scientists generally agree that para has not been proven to be a factor in causing Parkinson’s disease.
A representative from Syngenta expressed satisfaction with the decision, describing it as in line with numerous scientific studies that other experts have reviewed over the years.
Numerous paraquat lawsuits, most of them located in California, are currently awaiting resolution in state courts. The initial trials in state courts may take place later this year. At one point, attorneys representing the plaintiffs extensively promoted the paraquat legal action as a mass tort litigation. The cases were consolidated before Judge Rosenstengel in June 2021.
Since its introduction in the 1960s, Paraquat has been prohibited in over 60 nations worldwide. However, the U.S. Environmental Protection Agency has approved its restricted use, typically by certified professionals working on vast agricultural operations.
Syngenta sells herbicides in the United States under the trademark Gramoxone. Its continued popularity is partly due to some weeds developing resistance to Bayer’s Roundup, which is the subject of its mass tort lawsuit.
Syngenta is an affiliate of Sinochem, a state-owned Chinese company. The matter concerns the Paraquat Products Liability Litigation, which is being heard in the U.S. District Court for the Southern District of Illinois under case number 3:21-md-3004.