LINCOLN, Neb. (DTN) -- With Syngenta Crop Protection LLC now facing approximately 6,200 lawsuits alleging the use of the herbicide paraquat caused Parkinson's disease -- including about 1,200 cases in Philadelphia County, Pennsylvania, alone -- the company is seeking the Supreme Court's intervention.

Syngenta filed a petition with the court in May 2025 and received a boost from CropLife America in an amicus brief the group filed last month.

Syngenta is trying to put an end to the lawsuits, and in Pennsylvania, where out-of-state plaintiffs have been taking advantage of a state law that requires out-of-state companies to register to do business in the state, which subjects them to general personal jurisdiction in Pennsylvania courts.

According to Syngenta's petition, 90% of all paraquat cases filed in Pennsylvania are out-of-state plaintiffs who didn't buy, use or become exposed to the chemical in the state.

Syngenta asked the Supreme Court to consider whether the commerce clause allows a state to condition an out-of-state company's right to do business on submission to general personal jurisdiction. In addition, Syngenta questions whether the due process clause is violated when companies are required to submit to such a law.

Syngenta makes the argument that the current situation in Pennsylvania draws in plaintiffs who are shopping for favorable court forums.

The company said currently there are more than 100,000 out-of-state businesses registered in the state. Although Syngenta is registered there, the company said it does not own property and has just 15 employees in Pennsylvania.

"Only this court can answer the questions it left open in Mallory (v Norfolk Southern Railway Company)," Syngenta said in its petition.

"It should do so here and, most importantly, it should do so now -- before out-of-state defendants facing numerous mass-actions, class actions and other costly litigation in foreign forums where they have no meaningful presence, serves to coerce trials or settlements in cases that should never have been brought there in the first place."

In the 2023 Mallory case, the plurality of the Supreme Court held that Pennsylvania's registration statute did not violate due process.

In its amicus brief filed in June 2025, CropLife America said the Supreme Court should consider Syngenta's petition because in the Mallory case the court ruled in favor of a defendant that had "substantial" in-state operations.

CropLife America said two questions remain open: whether due process forbids registration-jurisdiction over defendants without significant in-state presence and whether the dormant commerce clause forbids registration jurisdiction in cases with no link to a particular legal forum.

"By upholding registration-jurisdiction -- but only on one specific set of facts -- Mallory upended that consensus," CropLife said in the brief.

"Now, any company registered to do business in Pennsylvania may or may not be subject to suit there on any cause of action arising anywhere in the world. Given Philadelphia's reputation as a plaintiff-friendly forum, plaintiffs' counsel have every reason to bring suit there against any registered company."

Syngenta said in its petition that while Parkinson's disease has existed for thousands of years and has been extensively studied, "beyond genetics, not a single environmental factor has been concluded to definitively cause Parkinson's disease to date -- including paraquat."

In January 2024, the U.S. Environmental Protection Agency said it found no scientific link between the use of paraquat and Parkinson's. Read about that here, https://www.dtnpf.com/….

Thousands of lawsuits have been filed against paraquat's registrants, Syngenta and Chevron Chemical Company, in the past several years, primarily product liability claims and alleged connections between the chemical and Parkinson's.

Use of paraquat, which is sold under brand names such as Gramaxone, Firestorm and Parazone among others, has increased steadily in the U.S. in the past decade, in response to the development of herbicide-resistant weeds.

Read more on DTN:

"Members of Congress Seek Paraquat End," https://www.dtnpf.com/…

Todd Neeley can be reached at todd.neeley@dtn.com

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