Risk of Parkinson’s Disease From Paraquat Lead to Calls To Ban Weed Killer

At least nine states have proposed bans or restrictions on the use of Paraquat, amid mounting evidence of Parkinson’s disease risks linked to the herbicide.

Some Pennsylvania lawmakers are calling for a ban on the weed killer Paraquat, citing research linking the herbicide to an increased risk of Parkinson’s disease and warning that its extreme toxicity outweighs its agricultural benefits.

According to a report by the Environmental Working Group (EWG) published on February 4, Pennsylvania is the latest of at least nine states to entertain bans or restrictions on the herbicide, with most proposed laws targeting its use near public schools.

Paraquat, originally sold under the brand name Gramoxone, became commercially available in the U.S. in 1964. It is widely used nationwide to kill broadleaf weeds and grasses before planting numerous types of crops. Paraquat is also sometimes sprayed on plants during harvest to dry them out.

The weed killer has long been known to be extremely toxic, with even small amounts posing a life-threatening risk if ingested. Additional concerns have emerged over the past few decades about the link between Paraquat and Parkinson’s disease, with reports suggesting that farm workers, landscapers and other individuals can be left with chronic and progressive neurological problems after routinely spraying, mixing or handling the herbicide.

This has led to more than 6,400 individuals pursuing Paraquat lawsuits in the federal court system, each raising similar allegations that the manufacturers failed to warn that farmers and agricultural workers may develop Parkinson’s disease, even when the product is used in accordance with safety instructions.

Several states have begun to respond to those concerns as well, with one of the latest being Pennsylvania. Last month State Senator Devlin Robinson, a Republican, and State Senator Nick Miller, a Democrat, introduced legislation for a Paraquat ban in that state.

They note that the herbicide is already banned in 70 countries, including the European Union and China, all of whom have found suitable replacements that do not increase the risk of Parkinson’s disease.

“Yet more than 10 million pounds of Paraquat is sprayed on American crops each year.  Other countries have found safer alternatives to Paraquat, and we think it’s time for Pennsylvania to do the same.”

– Paraquat Ban Memo to All Pennsylvania Senate Members, January 12, 2026

The text of the legislation has not yet been published for review, but similar proposals have been introduced in Illinois, Missouri, New Jersey, Vermont, Virginia, Washington, West Virginia and Utah, according to EWG. Parkinson’s disease groups like the Michael J. Fox Foundation support the various measures to limit Paraquat exposure. 

Paraquat Parkinson’s Disease Lawsuits

The proposed Pennsylvania ban was announced just before the first Paraquat bellwether trial was supposed to begin in a Philadelphia courtroom involving a lawsuit brought by Bill Merten, who indicates he developed Parkinson’s disease after years of spraying Paraquat as part of his landscaping business. However, Syngenta settled the lawsuit prior to the start of the trial.

The case is just one of thousands of Paraquat lawsuits awaiting resolution both at the state and federal levels, each raising similar allegations that Syngenta failed to disclose the substantial risk of Parkinson’s disease that users may face, even when all of the recommended handling instructions are followed.

Given common facts and law connecting all Paraquat Parkinson’s disease lawsuits, federal claims were consolidated into a multidistrict litigation (MDL) in June 2021 in the Southern District of Illinois, where U.S. District Judge Nancy Rosenstengel is presiding over coordinated discovery and pretrial proceedings.

In April 2025, attorneys announced that they were nearing a Paraquat Parkinson’s disease lawsuit settlement agreement. As a result, Judge Rosenstengal put a stay in place on all pretrial proceedings at the federal level. In December, she extended the Paraquat lawsuit stay until March 6, 2026.

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