After developing Parkinson’s disease from paraquat exposure, an Illinois man indicates Syngenta and Chevron intentionally concealed known health risks associated with their controversial weedkiller, due to the already-precarious position of the herbicide on the market in the U.S.

Dale Smith filed a complaint (PDF) in the U.S. District Court for the Northern District of California this week, alleging that the manufacturers have deceived both federal regulators and agricultural workers about the potential Paraquat risks, which may cause users to develop Parkinson’s disease after spraying, mixing or handling the toxic chemicals.

Paraquat has been widely used as a weed and grass killer for decades on farms throughout the United States, even though it has been banned in several countries due to the serious health risks. However, warnings and safety instructions provided for users largely focus on the risk of Paraquat poisoning, as ingesting even small amounts can result in fatal injuries.

In recent years, a number of studies have identified a link between Paraquat-based herbicides and the development of Parkinson’s disease, which is a serious and progressive neurological condition that causes shaking, stiffness and difficulty walking, balancing and difficulty coordinating body movements.

Smith’s lawsuit suggests that if the Paraquat Parkinson’s risks had been disclosed earlier, it may have been a tipping point that would have convinced regulators to recall the herbicide from the market in the U.S., allowing him to avoid a diagnosis received after uyears of exposure to the product.

“Many epidemiological studies (studies of the patterns and causes of disease in defined populations) have found an association between paraquat exposure and [Parkinson’s], including multiple studies finding a two- to five-fold or greater increase in the risk of [Parkinson’s disease] in populations with occupational exposure to paraquat compared to populations without such exposure,” the lawsuit states. “Defendants had knowledge of these studies and the relationship between paraquat exposure and [Parkinson’s] but actively and fraudulently concealed this information from Plaintiff and others.”

Parkinson’s affects more than 500,000 Americans, with approximately 50,000 new cases each year. The disease causes the loss of motor functions, causing imbalance and shaking, which gets progressively worse over time.

While genetics are often believed to be a major cause of Parkinson’s disease, growing research indicates that genes are only believed to be associated with about one-in-ten cases. Exposure to herbicides and pesticides are increasingly considered a leading risk, especially when combined with other factors that place individuals at risk of the development of Parkinson’s.

Studies have found farmers and agricultural workers exposed to the herbicide are several times more likely to develop the disease, and individuals with certain genetic variations may be 11 times more likely to be diagnosed with Parkinson’s.

Smith’s complaint joins a growing number of similar Parkinson’s lawsuits that have been filed throughout the federal court system in recent weeks by individuals exposed to Paraquat, either from direct handling of the herbicide, working in the same fields where it was sprayed or living near farmland where Paraquat was regularly applied. Each of the claims raise similar allegations, indicating that plaintiffs may have avoided a diagnosis if information about the Parkinson’s risk associated with Paraquat had not been concealed and hidden for decades.

 Tags: Chevron, Herbicide, Paraquat, Parkinsons Disease, Syngenta, Weed Killer