Paraquat is a toxic herbicide that has been linked to a variety of harmful conditions, most notably Parkinson’s disease. Farmers, agricultural workers, and those who live near industrial farms are most at risk of developing this neurodegenerative condition. Paraquat has been banned in 32 countries in the world, but it continues to be applied by commercially licensed users in the United States. Due to its high toxicity, paraquat is designated as a “restricted use” chemical.

What is Paraquat Poisoning?

Paraquat has been used since the early 1960s and became widely applied in the decades that followed, due in part to the growing resistance of certain weeds to Bayer AG’s best-selling product, Roundup. When used by commercial applicators, paraquat poisoning can occur if the individual inhales or ingests paraquat, has contact with plants treated with paraquat, or is involved in mixing and applying paraquat. Paraquat is highly toxic and can be lethal if ingested. Prolonged exposure to paraquat has been shown to caused deterioration of brain cells, leading to loss of control of motor function. This condition, known as Parkinson’s disease, causes diminished movement, tremors, and loss of balance.

What is the Status of Litigation against Paraquat Manufacturers?

Lawsuits against paraquat manufacturers, Syngenta Corp. (Syngenta) and Chevron USA (Chevron), are being handled in a multidistrict litigation (MDL) in southern Illinois. There are currently over 600 cases filed in the MDL. Syngenta sells paraquat in the United States under the brand name Gramoxone. Prior to 1986, paraquat was distributed by Chevron.

Hundreds of agricultural laborers, farmers, and other plaintiffs allege that they developed Parkinson’s disease after being exposed to paraquat through their occupations. In February 2022, U.S. District Judge Nancy Rosenstengel denied Syngenta and Chevron’s motions to dismiss claims for strict product liability, negligence, breach of implied warranty, and violations of consumer protection laws in several states. While the Judge also acknowledged that the plaintiff’s public nuisance claim is a “simple repackaging” of its product liability claim, the judge’s ruling is a victory for plaintiffs who can now proceed with the majority of their legal claims.

A bellwether trial under Judge Rosenstengel is expected to be held in November 2022.

What are the Claims against Syngenta and Chevron?

Plaintiffs in the MDL allege that Syngenta and Chevron had knowledge of scientific studies that established a link between exposure through occupational routes and an increased risk of Parkinson’s disease. Despite being aware of the risk of Parkinson’s, the manufacturers failed to adequately warn users.

Scientific studies have confirmed that exposure to paraquat is associated with the neurological symptoms that are the hallmarks of Parkinson’s disease. According to the National Institutes of Health, individuals who used paraquat developed Parkinson’s approximately 2.5 times more than those who had no contact with the herbicide. The report noted that paraquat expands the production of oxygen derivatives that can impair cell structures. Additional research supports the idea that prolonged exposure to paraquat at low levels through airborne contact causes the chemical to enter into the brain where it generates changes that correlate with deviations seen at the onset of Parkinson’s.

The case is In re Paraquat Liability Litigation, U.S. District Court, Southern District of Illinois, No. 21-md-03004.