Paraquat litigation · Evidence guide

The paraquat cases ask courts to weigh a genuinely contested Parkinson's record

Plaintiffs allege paraquat exposure caused Parkinson's disease. EPA says the studies conflict and has not found a clear link from labeled uses, while its regulatory review continues.

WeSpeakLaw EditorialUpdated August 24, 2026

Plaintiffs allegeExposure caused Parkinson'sAn allegation, not a finding
EPA positionStudies conflictRegistration review remains active
Cohort researchEarlier association not reproducedOne study does not settle the literature

What plaintiffs allege

The centralized lawsuits allege that paraquat exposure caused Parkinson's disease. The JPML grouped cases with that shared question, but centralization is not a finding that paraquat causes the disease generally or in any one person.

Why the science remains disputed

EPA says the epidemiological literature contains conflicting results and that it has not found a clear link between labeled paraquat uses and Parkinson's disease. A 2020 Agricultural Health Study analysis did not reproduce an earlier paraquat association. That study matters, but one cohort cannot by itself settle the entire literature or an individual's exposure history.

EPA's registration review remains active. The agency is also seeking more information after newer vapor-pressure data increased uncertainty about possible volatilization and bystander exposure. Regulatory review and civil liability use different legal standards.

A dated view of the federal docket

MDL 3004 is in the Southern District of Illinois before Chief Judge Nancy J. Rosenstengel. JPML listed 6,665 actions pending on August 3, 2026. The count does not establish exposure, diagnosis or outcome.

Verification ledger

Primary sources

U.S. Judicial Panel on Multidistrict Litigation

Paraquat transfer order

The official scope of the centralized allegations.

MDL 3004, Document 506

U.S. Environmental Protection Agency

Paraquat Dichloride

EPA's current scientific position and ongoing review.

Human health · Registration Review

U.S. Judicial Panel on Multidistrict Litigation

Pending MDLs

The dated federal docket snapshot.

Page 1, MDL 3004

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