The multidistrict litigation (MDL) concerning paraquat-based herbicides — In re: Paraquat Products Liability Litigation, MDL No. 3004 (S.D. Ill.) — has become a focal point in mass torts. Thousands of plaintiffs allege that exposure to paraquat caused them to develop Parkinson’s disease (PD). The litigation has featured high-stakes scientific disputes, key defense wins, a master settlement agreement, and now Case Management Order No. 25 (CMO 25, 2026 WL 1707147), a Lone Pine order with important implications for nonsettling plaintiffs and a potential roadmap for effective case management in other MDLs.
In April 2024, the MDL court excluded the plaintiffs’ sole expert on general causation. That ruling left the plaintiffs unable to establish general causation, and the court accordingly granted the defendants’ motion for summary judgment. But that ruling only formally applied to the four bellwether cases; while the bellwether plaintiffs’ inability to establish general causation portended problems for every plaintiff in the MDL, the litigation continued.
As we have discussed before (for example, in regard to the acetaminophen MDL and the Deepwater Horizon BELO cases), it is not uncommon for the remaining plaintiffs in such circumstances to try again — often unsuccessfully — with a different set of general causation experts. In Paraquat, though, the parties focused on settlement negotiations. By August 2025, those talks culminated in a master settlement agreement. However, not all plaintiffs were eager to participate.
Lone Pine orders are case-management tools that require plaintiffs to produce evidence supporting key elements of their claims. CMO 25 applies that screening function while the settlement process is underway and gives covered plaintiffs notice of what they must gather before further discovery. The core requirements of CMO 25 include:
- Special master meeting for settlement opt-outs. Plaintiffs who received a settlement offer and declined, or have not decided whether to accept, must contact the special master within 30 days to arrange a personal meeting at which the offer will be discussed. Plaintiffs who still opt out after the meeting must submit a wet-ink certification confirming the meeting.
- Rule 26(a) disclosures, plaintiff’s fact sheet, and medical summary. Each plaintiff must serve initial disclosures, complete the plaintiff’s fact sheet, and produce a summary of pertinent medical records with citations and excerpts.
- Proof of paraquat use, tiered by time period. Recent use requires documentary proof; intermediate use permits a nonfamily affidavit fallback with corroboration; and pre-1995 use permits a family affidavit fallback if other proof cannot be obtained.
- Witness affidavits. Any witness to alleged paraquat use must provide a sworn affidavit describing the use in detail, including location, frequency, method of application, and protective equipment.
- Diagnosis and causation proof. Plaintiffs claiming PD must produce a qualifying diagnosis at least 10 years after first alleged exposure and a case-specific Rule 26 expert report addressing exposure, diagnosis, alternative causes, and causation.
- Counsel affidavit, choice of law, and limitations information. Counsel must attest to claim investigation and merit, identify the asserted choice of law, and, for post-CMO cases filed in, removed to, or transferred to the MDL, provide the required limitations-related affidavit.
- Noncompliance. After notice and a 30-day cure period, unresolved deficiencies may lead to an order to show cause and, in the court’s discretion, dismissal with prejudice or other terms.
Interestingly, CMO 25 does not set any deadlines for the requirements other than meeting with the special master to discuss settlement. The court overtly issued the order to give nonsettling plaintiffs “notice of what will be required of them” and a chance to “begin to gather the required information.”
The court’s grant of summary judgment against a full slate of bellwether plaintiffs for inability to establish general causation should have given the remaining plaintiffs plenty of incentive to accept a settlement offer. CMO 25 now further urges the remaining plaintiffs toward the exit door, not only requiring nonsettling plaintiffs to meet personally with a special master but also giving advance notice of how onerous life postsettlement will become.
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