Paraquat Lawsuits 2026: Syngenta Settles First Trial as 6,400 Federal Cases Mount

Syngenta settled the first-ever U.S. paraquat-Parkinson's disease trial one day before it was set to begin in January 2026 in Philadelphia. The plaintiff, Bill Mertens, is a 77-year-old retired landscaper who was exposed to paraquat during the 1980s and 1990s and was diagnosed with Parkinson's disease in 2021. More than 6,400 federal cases remain pending in MDL-3004, the eighth-largest active multidistrict litigation in the country.

The Mertens settlement marked the second time in six months that Syngenta resolved a paraquat case on the eve of trial. The company has never allowed a paraquat-Parkinson's claim to reach a jury verdict. In 2021, Syngenta paid $187 million in a multi-plaintiff settlement. The pattern suggests the manufacturer is unwilling to test its defense in front of jurors — a signal plaintiff firms are watching closely.

The Science Behind the Lawsuits

The causation evidence connecting paraquat to Parkinson's disease has been building for more than a decade. A 2019 meta-analysis of 13 epidemiological studies found that paraquat exposure increased the risk of Parkinson's disease by 64%. One study within that body of research found exposed individuals were more than twice as likely to develop the disease compared to unexposed populations.

The Michael J. Fox Foundation has submitted multiple studies to the EPA supporting the link between paraquat and Parkinson's. Despite this, the EPA dismissed approximately 90 articles of evidence in its 2024 review. An updated 2020 Agricultural Health Study found no association, contradicting earlier research — a discrepancy that defendants have cited in their defense.

Paraquat remains one of the most widely used herbicides in the United States, with more than 10 million pounds applied annually. It is banned in more than 60 countries, including all EU member states, China, and Canada.

Where the Litigation Stands

MDL-3004 is centralized before Judge Nancy J. Rosenstengel in the Southern District of Illinois. The more than 6,400 pending federal cases represent a fraction of the total — approximately 8,000 cases exist when including state courts.

A tentative global settlement agreement was reached in April 2025, but it remains unsigned. The presiding judge paused case work while settlement details are finalized, leaving thousands of plaintiffs in limbo. Whether the framework holds — and what it pays per claim — remains unclear.

For plaintiff firms, the pre-trial settlement pattern creates a dual challenge: building cases strong enough to force favorable settlements while preparing for the possibility that the global framework collapses and individual trials proceed.

The Medical Records Challenge

Paraquat cases present a uniquely difficult records problem. The latency period between herbicide exposure and a Parkinson's diagnosis can span 10 to 30 years. A landscaper or farmworker exposed in the 1980s may not have received a Parkinson's diagnosis until the 2010s or later.

Building a viable case file requires Parkinson's disease diagnosis records from neurologists or movement disorder specialists, treatment histories showing disease progression, employment or farm records proving proximity to paraquat application, and occupational health records documenting chemical exposure. Many of these records originate from rural healthcare providers, agricultural cooperatives, or employers that may no longer exist.

The challenge is compounded by the nature of Parkinson's itself. Diagnosis is clinical — there is no single definitive test. Records must show a pattern of symptoms, specialist evaluations, and treatment that collectively support the diagnosis. Firms that cannot assemble this evidence across decades of care will struggle to survive summary judgment, let alone negotiate meaningful settlements.

What Firms Should Watch in 2026

The Bottom Line

The paraquat-Parkinson's litigation is at an inflection point. Syngenta's refusal to let a single case reach a jury, combined with a tentative settlement framework and a new EPA review, suggests 2026 will be the year that defines case values for thousands of plaintiffs.

For firms handling paraquat cases, the work is in the records. Exposure histories, neurological diagnosis documentation, and occupational records spanning decades are what separate cases that settle from cases that stall. The firms that solve the evidence problem first will capture the most value from whatever resolution this litigation produces.

Sources: The New Lede, Drugwatch, AboutLawsuits, AboutLawsuits MDL Updates, EWG, EPA, Drugwatch EPA Review.