Paraquat Weed Killer

Hausfeld’s US Product Liability and Environmental Practice Group is working with leading experts to investigate claims on behalf of California farm and agricultural workers with long-term exposure to the weed killer Paraquat, who have been diagnosed with Parkinson’s Disease.

Paraquat is one of the most dangerous products our group has ever investigated. One sip can kill an adult. It has been banned in over 30 countries, including the countries where the product originally was developed. This is the same product that was used by law enforcement agents in the 1970s to wipe out marijuana and poppy fields in Mexico. Yet it remains available in the United States as a powerful weed killer, under a restricted use license. So it comes as little surprise to us that Paraquat is not just a poison, but a potent neurotoxin capable of causing, or at least accelerating the early onset of Parkinson’s Disease. 

The scientific community has been investigating and studying the association between Paraquat and Parkinson’s Disease for decades. The companies involved in the manufacturing, marketing and, distribution of Paraquat (Syngenta and Chevron USA) are expected to know, and under the law are held to the standard of knowing the state of the science, which for some time has linked their product to Parkinson’s and related movement disorders. Yet the companies have never acknowledged or warned about the connection, or otherwise taken reasonable and necessary steps to protect farm and agricultural workers from exposure to the neurotoxic effects of chronic and long-term use of Paraquat. 

Parkinson's disease is a progressive nervous system disorder that affects movement. Symptoms start gradually, sometimes starting with a barely noticeable tremor in just one hand. Tremors are common, but the disorder also commonly causes stiffness or slowing of movement that can often progress. According to the Mayo Clinic: "Over time, Parkinson's disease may slow your movement, making simple tasks difficult and time-consuming. Your steps may become shorter when you walk. It may be difficult to get out of a chair. You may drag your feet as you try to walk. Muscle stiffness may occur in any part of your body. The stiff muscles can be painful and limit your range of motion. Your posture may become stooped, or you may have balance problems as a result of Parkinson's disease.  You may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging your arms when you walk. You may speak softly, quickly, slur or hesitate before talking. Your speech may be more of a monotone rather than have the usual inflections." These conditions often worsen and can become debilitating.  Other changes that can result from Parkinson’s include:

  • Thinking difficulties
  • Depression and emotional changes
  • Swallowing problems
  • Chewing and eating problems
  • Sleep problems and sleep disorders
  • Bladder problems; and
  • Constipation.

There is no cure and no normalizing treatment for this disease, meaning that, once diagnosed, these workers suffer endlessly for the remainder of their lives, and many become unable to work and provide for their families. Relationships with loved ones are forever changed. Parkinson’s Disease is typically not seen in adults under the age of 60, but due to exposure to Paraquat, diagnoses can be seen in farm workers in their 50s, or even younger.    

Hausfeld is directing its resources, knowledge and toxic tort litigation experience to assist California-based farm and agricultural workers with sufficient exposure to Paraquat and a diagnosis of Parkinson’s Disease, in lawsuits against Syngenta and Chevron in California state courts. Paraquat historically has been used more in California than most any other state. Chevron USA, which has played a central role in the marketing and distribution of Paraquat, also maintains its headquarters in California. A California jury is therefore well-suited to hear these workers' stories and decide fair and just compensation for the devastation caused by Parkinson’s Disease as a result of Syngenta and Chevron’s choice to place profits over the well-being and safety of America’s farm and agricultural workers.


If you or a loved one engaged in California farm or agricultural work, was exposed long term to Paraquat and diagnosed with Parkinson’s Disease, please contact our California-based mass tort paralegal Ramon Rodriguez (, or complete this form, so we can further investigate your potential claim.

Please do not include any confidential information when contacting the related lawyers or submitting this form. No lawyer-client relationship is formed unless and until an engagement agreement is signed.

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