A U.S. judicial panel has ordered the pretrial consolidation of dozens of lawsuits against Syngenta and Chevron over allegations that paraquat weed killer, which has been used widely around the world for more than 50 years, causes Parkinson’s disease.

The U.S. Judicial Panel on Multidistrict Litigation said that “to date, 77 actions and potential tag-along actions are pending in sixteen different districts,” and they all involve “common factual issues concerning the propensity of paraquat to cause Parkinson’s Disease.” The cases will include “complex scientific and regulatory issues,” the panel said.

“Centralization will eliminate duplicative discovery; avoid inconsistent pretrial rulings; and conserve the resources of the parties, their counsel and the judiciary,” the panel stated in its order.

The panel determined the cases will be transferred to the federal court in the Southern District of Illinois and assigned to U.S. Judge Nancy Rosenstengel for handling.

Lawyer Majed Nachawati, whose firm is among those representing hundreds of plaintiffs suing Syngenta and Chevron, applauded the decision, and said the litigation is “monumentally important.” It was Nachawati’s firm that requested the MDL.

Syngenta, a Swiss company owned by a larger Chinese chemical company, developed and markets the paraquat-based Gramoxone brand, while Chevron has been a distributor of Syngenta’s paraquat products in the United States.

The formation of the paraquat multidistrict litigation (MDL) underscores the legal threat Syngenta faces in the litigation.  An MDL was also formed for the lawsuits filed against Monsanto over allegations that its Roundup weed killers cause non-Hodgkin lymphoma; ultimately tens of thousands of people sued the company for such claims and Monsanto’s owner, Bayer AG, is now facing settlement payouts of more than $10 billion.

Syngenta said in a statement that it agrees with the decision to coordinate the various federal lawsuits before one judge.

“This will help the parties and the courts proceed in a timely and efficient way,” the company said.

Chevron did not respond to a request for comment.

Used since the ’60s

Paraquat has been used in the United States since 1964 as a tool to kill broadleaf weeds and grasses. Farmers often use paraquat before planting crops or before those crops emerge. It has long been known to be extremely dangerous to anyone who ingests even a small amount, and regulators have issued warnings and placed restrictions on its use because of poisoning risks.

The body of science showing links between Parkinson’s disease and paraquat is less clear, having evolved over time. The EPA does not currently confirm a causal link to Parkinson’s disease. But many scientists say the research showing causation is robust.

Several scientific studies have linked paraquat to Parkinson’s, including a  large study of U.S. farmers  jointly overseen by multiple U.S. government agencies.

The Agricultural Health Study (AHS), which is backed by numerous U.S. agencies and researchers, has found that “exposure to agricultural pesticides may increase a person’s risk of developing Parkinson’s disease.” And in 2011, AHS researchers reported that participants who used paraquat or another pesticide were “twice as likely to develop Parkinson’s disease” as people who were not exposed to those chemicals.

Syngenta maintains that newer and better research, including by AHS scientists, has discounted a tie between paraquat and Parkinson’s.

In addition to the cases brought on behalf of people suffering from Parkinson’s, additionally, a  class action lawsuit was filed in federal court in Iowa on May 3 by a law firm representing people who fear they may get the disease in the future.

The suit seeks “equitable relief in the form of medical monitoring, including, but not limited to, the costs of diagnostic testing” for farmers and others exposed to paraquat who are allegedly at “increased risk” for Parkinson’s, according to the legal filing.

Settlement rumors

What was supposed to be the first trial over allegations that Syngenta’s paraquat causes Parkinson’s has been delayed multiple times and the parties may be nearing a settlement, according to sources close to the case.

The trial in the case of  Hoffman V. Syngenta is pending in St. Clair County Circuit Court in Illinois and has had multiple trial dates set and then cancelled, the most recent earlier this month.

The lawyer for the plaintiffs in that case had pronounced publicly that he had internal Syngenta documents that would expose the company’s alleged knowledge of connections between paraquat and Parkinson’s.

But Syngenta steadfastly has denied any such evidence exists.

“Syngenta has great sympathy for the health issues faced by the plaintiffs and others suffering from the debilitating effects of Parkinson’s disease,” the company’s statement reads.  “We care deeply about the health and well-being of farmers and are dedicated to providing them safe and effective products. There is no credible evidence that Paraquat, which has been widely used for more than 55 years, causes Parkinson’s disease.  No peer reviewed study, including the largest study which involved 38,000 farmers, has ever concluded Paraquat causes Parkinson’s disease.  The EPA and other government authorities have extensively analyzed this issue and similarly found no evidence that Paraquat causes Parkinson’s disease. The facts simply do not support the Plaintiffs’ allegations, and we intend to defend this product and our legal position vigorously in court.”