Potential Link Between Chlorpyrifos Exposure and Parkinson’s Disease in Gulf War Veterans

Veterans who served during Operations Desert Shield and Desert Storm may have been exposed to chlorpyrifos, an insecticide used by the U.S. military to control flies, sand flies, mosquitoes, and other pests in the Persian Gulf region. More than three decades later, research linking long-term chlorpyrifos exposure to an increased risk of Parkinson’s disease is raising questions about the potential long-term effects of exposure among Gulf War veterans.

A recent UCLA Health study found that people with long-term residential exposure to chlorpyrifos had more than 2.5 times the risk of developing Parkinson’s disease compared with people without such exposure. The research did not specifically examine Gulf War veterans, and it does not establish that veterans exposed during military service will develop Parkinson’s disease. However, the findings add to ongoing research examining pesticides as potential environmental risk factors for the neurological disorder.

Chlorpyrifos Insecticide and its Alleged Link to Parkinson’s Disease

Chlorpyrifos is an organophosphate insecticide that has been widely utilized in agriculture since it was introduced in the 1960s. Originally developed by Dow Chemical Company, it was designed to target a variety of pests by inhibiting the enzyme acetylcholinesterase, which is crucial for proper nerve function. While effective in controlling pests, this same mechanism has the potential to pose serious risks to human health due to chlorpyrifos’ neurotoxic properties, particularly for those exposed over extended periods.

Concerns surrounding chlorpyrifos have resulted in restrictions on its use over the years. Most residential uses of the pesticide were phased out in the United States beginning in 2000, although chlorpyrifos continued to be widely used in agriculture. Researchers have continued to study whether long-term exposure may contribute to neurological conditions, including Parkinson’s disease.

What is Parkinson’s Disease?

Parkinson’s disease is a progressive neurological disorder characterized by the degeneration of dopamine-producing neurons in the brain. Symptoms of Parkinson’s disease often develop gradually and can include tremors, muscle stiffness, slowed movement, and balance issues. Parkinson’s disease can also cause non-movement symptoms, and the disease may progress differently from one person to another.

Recent research has examined the potential connection between chlorpyrifos exposure and Parkinson’s disease. In a 2025 study conducted by UCLA Health, researchers found that individuals with long-term exposure to chlorpyrifos were over 2.5 times more likely to develop Parkinson’s disease compared to those without such exposure. 

The study found that chlorpyrifos exposure can disrupt autophagy, a cellular process responsible for clearing damaged proteins from the brain. When this process is disrupted, abnormal proteins can accumulate and contribute to inflammation and neuronal damage. The researchers concluded that their findings support chlorpyrifos exposure as a potential risk factor for Parkinson’s disease.

Chlorpyrifos Use by the Military During the Gulf War

During the Gulf War, the U.S. military reportedly deployed large quantities of chlorpyrifos to combat insect infestations that posed threats to troops. An analysis of Gulf War pesticide exposures by the National Academies indicates that nearly 48,000 bottles of chlorpyrifos were shipped to the Persian Gulf during the conflict. A review of harmful environmental exposures in the Persian Gulf estimates that roughly 8,400 pounds of chlorpyrifos were available during Operations Desert Shield and Desert Storm. 

The widespread availability of chlorpyrifos during the Gulf War raises questions about the potential long-term health effects on servicemembers who may have been exposed to the insecticide. However, the amount of chlorpyrifos actually used and the extent of individual servicemembers’ exposure remain unclear. Exposure levels could have varied considerably depending on where troops were stationed, their duties, and how pesticides were applied. 

Parkinson’s Disease Diagnosis and Intervention

Parkinson’s disease can be difficult to diagnose, particularly in its early stages, because symptoms often develop gradually and can overlap with those of other neurological conditions. There is no single test used to diagnose Parkinson’s disease, so physicians generally consider a patient’s symptoms, medical history, and neurological examination when evaluating the condition.

For Gulf War veterans, discussing military service and potential pesticide exposures with a healthcare provider may provide additional context when reviewing their health history. Veterans experiencing persistent tremors, muscle stiffness, slowed movement, balance problems, or other neurological changes should seek a medical evaluation. While there is currently no cure for Parkinson’s disease, treatment can help manage symptoms and maintain quality of life.

Continued Research Into Chlorpyrifos Exposure and Parkinson’s Disease

The potential link between chlorpyrifos exposure and Parkinson’s disease raises new questions about the long-term health of Gulf War veterans who may have encountered the insecticide during military service. However, more research is needed to determine whether veterans exposed to chlorpyrifos during Operations Desert Shield and Desert Storm face an increased risk of developing Parkinson’s disease. As Gulf War veterans continue to age, research into the long-term effects of pesticide and other environmental exposures may provide a clearer understanding of the potential health consequences associated with their service.