Paraquat: The Pesticide Linked to Parkinson's Disease and Thousands of Lawsuits

A Common Agricultural Chemical with Devastating Neurological Consequences

Paraquat dichloride is one of the most widely used herbicides in the world, applied on millions of acres of farmland to control weeds and grasses. It has been commercially available since the 1960s and is sold under various brand names, including Gramoxone (manufactured by Syngenta). While it is banned or restricted in many countries due to its toxicity, paraquat remains legally available and heavily used in the United States.

The Parkinson's Disease Connection

Scientific research spanning decades has increasingly linked paraquat exposure to an elevated risk of developing Parkinson's disease, a progressive neurological disorder that affects movement and cognitive function. Studies have found that individuals who lived near fields where paraquat was sprayed, or who worked directly with the chemical as farm laborers or applicators, faced significantly higher rates of Parkinson's disease diagnosis compared to the general population.

Animal studies have shown that paraquat causes the death of dopamine-producing neurons in the brain — precisely the mechanism underlying Parkinson's disease. The National Institutes of Health (NIH) and multiple epidemiological studies have supported the association, though the chemical industry has long contested this link.

The Growing Litigation Wave

Tens of thousands of Parkinson's disease patients who were exposed to paraquat have filed lawsuits against Syngenta and Chevron (which previously manufactured and sold paraquat under the Ortho brand). These cases have been consolidated in federal MDL proceedings in the Southern District of Illinois. Plaintiffs allege that manufacturers knew or should have known about the neurotoxic risks and failed to adequately warn users.

The paraquat litigation remains active and evolving, with no comprehensive settlement reached as of publication. Some cases have resulted in significant plaintiff victories at the trial level, while manufacturers continue to dispute the scientific evidence.

Regulatory Implications

The paraquat litigation has fueled calls for a U.S. ban on the chemical, mirroring restrictions already in place in the European Union, China, and dozens of other countries. The EPA has faced criticism for repeatedly renewing paraquat's registration despite mounting scientific evidence of its neurological risks. For affected patients and their families, the paraquat cases represent a fight not just for compensation, but for the broader recognition that occupational chemical exposure can have life-altering neurological consequences.