While the exact cause of Parkinson’s disease remains under investigation, new research focuses on the possibility of environmental factors, such as long-term exposure to certain pesticides. While there are hundreds of different types of pesticides used throughout the United States for both agricultural and non-agricultural uses, current research focuses on several chemicals that may increase a person’s risk of developing the neurodegenerative condition.
A 2026 UCLA Health study focused on the connection between a widely used pesticide, chlorpyrifos, and Parkinson’s, instead of pesticides as a broad group. The study suggests that people with long-term estimated residential exposure to chlorpyrifos had a 2.5x greater risk of developing the disease. The research highlights the idea that specific pesticides, including chlorpyrifos, may be linked with Parkinson’s.
What Is Parkinson's Disease?
Parkinson’s disease is a progressive neurological condition that affects more than 1.1 million people in the U.S. Almost 90,000 Americans are newly diagnosed with the condition each year. Currently, there is no cure for the disease, and its overall cause remains under investigation.
The neurodegenerative disease damages dopamine-producing (dopaminergic) neurons in a part of the brain called the substantia nigra. Symptoms of the disorder may progress slowly and may include tremors, slow movements, limb stiffness, gait difficulties, and postural instability (balance problems).
While genetic factors may play a role in some cases, new research indicates that environmental factors may also contribute to disease development in some people. Long-term exposure to certain pesticides has been associated with an increased risk of developing Parkinson’s in recent studies, which focus on how these chemicals may damage brain cells.
Paraquat & Parkinson’s Disease
Paraquat is one of the most widely used pesticides in the world. It has also been one of the most studied as it relates to a potential connection to Parkinson’s disease. Paraquat or paraquat dichloride is a highly effective, fast-acting herbicide that has been used since the 1960s. Due to its high toxicity, the pesticide is classified as a Restricted Use Pesticide, which can only be handled by licensed applicators, according to the EPA.
Paraquat has been banned in over 70 countries, including in China and the European Union. Despite these restrictions, it remains legal in the U.S.
A 2011 study published in Environmental Health Perspectives found that individuals who were exposed to the pesticides paraquat or rotenone were 2.5x more likely to develop Parkinson’s compared to those who did not use either pesticide. According to the study, exposure to paraquat can cause oxidative stress, a potential mechanism for Parkinson’s disease.
In March 2026, a major producer of paraquat, Syngenta, announced it would cease global production by the end of June. The company cited “significant competition from generic producers” as its reasoning for ending production at its U.K. manufacturing facility. Despite this commitment from Syngenta, other manufacturers may continue to produce, market, and sell the herbicide in the U.S. and worldwide.
Chlorpyrifos & Parkinson’s Disease
Another pesticide widely looked at for a potential link to Parkinson’s disease is chlorpyrifos. The pesticide is a broad-spectrum organophosphate pesticide used in the U.S. since 1965. Originally manufactured by Dow Chemical and later marketed by Dow AgroSciences (whose agricultural business became part of Corteva Agriscience), the widely used chemical has been sold under several names, including Dursban, Lorsban, and Cobalt.
In 2000, the EPA reached an agreement to phase out most residential uses of the pesticide. Then, in 2021, the EPA effectively banned the use of chlorpyrifos on food crops. However, the rule was vacated in 2023 by a federal appeals court. Subsequent restrictions mean that chlorpyrifos may be used on only 11 specified food and feed crops in certain states as of July 2025, subject to additional limitations. The EPA’s registration review remains ongoing.
A 2026 UCLA Health study found that individuals with long-term residential exposure to chlorpyrifos were 2.5x more likely to develop Parkinson’s compared to those who were not exposed to the pesticide. The study combined both human population data and laboratory animal experiments. In the laboratory experiments, chlorpyrifos exposure damaged dopamine-producing neurons and led to a buildup of alpha-synuclein — both processes seen in the brains of people with Parkinson’s.
Who Is Most at Risk of Parkinson’s After Pesticide Exposure?
A study of individuals in California’s Central Valley found that those living near where pesticides were frequently used had an elevated risk of developing Parkinson’s disease. Exposure may occur through contaminated groundwater, direct contact, airborne drift, or contact with contaminated soil.
Individuals who may be most at risk of developing Parkinson’s after exposure to certain pesticides:
- Farmworkers
- Licensed applicators
- Agricultural workers
- Individuals living near agricultural fields, orchards, or golf courses
- Residents drinking from a contaminated water source
Since Parkinson’s disease is a slow-moving, progressive disease, it can take years or even decades for symptoms to appear. Individuals are encouraged to document any symptoms and keep detailed medical records.
Where the Litigation Stands
Current litigation against the makers of paraquat and chlorpyrifos alleges that the manufacturers knew or should have known about the potential risk of harm associated with exposure to the chemicals. Lawsuits also allege the companies, including Syngenta, Chevron, and others, failed to adequately warn consumers about these risks.
Litigation against pesticide manufacturers, particularly those who make, sell, and market chlorpyrifos, is in its early stages. Law firms across the U.S. continue to evaluate and accept cases on behalf of those diagnosed with Parkinson’s after exposure to one of these insecticides.
Contact Wisner Baum for a Free Case Evaluation
Individuals who believe that exposure to a pesticide may have played a role in their Parkinson’s diagnosis are encouraged to seek legal counsel. Those who may have been harmed by exposure do not need to have all of the information prior to contacting an attorney. An experienced lawyer can help to secure evidence linking exposure to the condition. Every case is different, and not all Parkinson’s patients will qualify to take legal action. Factors such as the type of pesticide exposure, duration and timing of exposure, and a person’s medical history may all affect whether a person meets the qualifying criteria.
Affected individuals are encouraged to contact Wisner Baum at (310) 207-3233 to schedule a free consultation. All case evaluations are confidential and provided without obligation to retain the firm.
Pesticides & Parkinson’s Disease FAQs
Does exposure to pesticides cause Parkinson’s disease?
Research shows that exposure to certain pesticides may increase a person’s risk of developing Parkinson’s disease. While research continues into the potential link between pesticide exposure and the disease, individuals who may have been exposed to paraquat, chlorpyrifos, or another pesticide and were subsequently diagnosed with Parkinson’s may be able to take legal action.
Has paraquat been banned in the United States?
Paraquat has not been banned in the United States. It continues to be used throughout the country, despite being banned in a number of other countries. It is currently a Restricted Use Pesticide, meaning only licensed applicators handle the product.
Who is eligible to file a pesticide lawsuit?
Individuals who were exposed to pesticides either through their work or residence may be eligible to file a lawsuit against the manufacturers if they were diagnosed with Parkinson’s and their diagnosis can be connected to the exposure.
How long does it take Parkinson’s symptoms to show up after exposure?
Parkinson’s disease is a slow-moving, progressive disease. It can take years to decades for symptoms to show up after exposure to a pesticide. Many people do not realize that their condition may be linked to pesticide exposure because of the long latency period.
How do I prove pesticide exposure caused my Parkinson’s?
The best way to prove pesticide exposure potentially caused Parkinson’s is with the help of an attorney. An attorney can help to determine whether you qualify to take legal action against a pesticide manufacturer.
What chemicals have been linked to Parkinson’s?
Several pesticides have been potentially linked to an increased risk of Parkinson’s, including paraquat, chlorpyrifos, and rotenone. Research continues to help determine the connection between these pesticides and the neurodegenerative disease.
