Paraquat is one of the most widely used herbicides in American agriculture—and one of the most toxic. For decades, farmworkers, pesticide applicators, and agricultural employees across California and the rest of the country have been exposed to this chemical as part of their daily work. A growing body of scientific evidence now links paraquat exposure to a significantly increased risk of Parkinson’s disease, a progressive neurological disorder with no cure. Thirty-two countries around the world have already banned paraquat. The United States has not.

What Is Paraquat

Paraquat dichloride is a toxic chemical herbicide used to control weeds and grasses in agricultural settings. It is one of only two herbicides still used in the United States that is banned in the European Union. Paraquat is so toxic that a single sip can be fatal, and it is classified as a restricted-use pesticide that can only be applied by licensed applicators. Despite these restrictions, exposure occurs routinely through inhalation of spray drift, skin contact during mixing and application, and environmental contamination of soil and water near application sites.

The Connection to Parkinson’s Disease

Parkinson’s disease is a progressive disorder of the nervous system that affects movement, balance, and coordination. Symptoms include tremors, stiffness, slowed movement, and difficulty with balance and speech. As the disease progresses, it can lead to severe disability, cognitive decline, and loss of independence.

Research has consistently shown that paraquat exposure increases the risk of developing Parkinson’s disease. A 2019 study found that individuals exposed to paraquat had a 25 percent higher chance of developing the disease. The risk increases with the duration and intensity of exposure. The chemical appears to damage dopamine-producing neurons in the brain—the same neurons whose loss drives Parkinson’s symptoms.

Who Is at Risk

The people most affected by paraquat exposure are those who worked directly with the chemical: farmworkers who applied it to crops, agricultural laborers who worked in fields where it was sprayed, pesticide mixing and loading workers, and residents living near agricultural operations where paraquat was used. California’s agricultural workers are particularly affected given the state’s massive farming industry. In January 2026, California enacted Assembly Bill 1963, banning paraquat effective immediately—but for many workers, the exposure has already occurred.

Current Litigation and Compensation

More than 6,400 paraquat lawsuits are consolidated in a federal multidistrict litigation against Syngenta and Chevron, the primary manufacturers and distributors of the chemical. A confidential settlement agreement was reached in April 2025, with finalization expected by March 2026. Claimants may be entitled to compensation for Parkinson’s disease diagnosis and treatment, neurological care and medications, lost wages and disability, pain and suffering, diminished quality of life, and care assistance as the disease progresses.

If you or someone you love was exposed to paraquat through agricultural work and has been diagnosed with Parkinson’s disease, you have the right to seek compensation. Beverly Wilshire Law APC can evaluate your case at no cost. Call (310) 424-5566 or email info@bevwilshire.com for a consultation—we’re here to guide you in the right direction.