The Link Between Paraquat and Parkinson’s Disease

The Link Between Paraquat and Parkinson’s Disease
The Link Between Paraquat and Parkinson’s Disease

The weed killer Paraquat has been a staple for moderate to large-scale agricultural businesses since its introduction in the early 1960s. However, a growing number of Parkinson's disease advocacy groups have sounded the alarm about its potential to contribute to or cause Parkinson’s Disease. For instance, a 2017 letter from the Unified Parkinson’s Advocacy Council informed the EPA that exposure to Paraquat in teenagers and young adults increased their likelihood of developing Parkinson's disease anywhere from 100 to 500%. 

Alongside a bevy of clinical research and high-profile Paraquat litigation, the regulatory and legal landscape for the production, distribution, and marketing of the ubiquitous herbicide is likely to endure a dramatic change in coming years. 

Paraquat Use and the Risk of Herbicide Contamination

Paraquat dichloride is a staple herbicide in the agricultural industry. Commonly sold under the name brands Gramoxone, Parazone, and Firestorm, it assists farmers in the eradication of weeds and defoliation before harvests. 

However, Paraquat is a highly hazardous toxin, which can have long-term and irreversible side effects. Although banned throughout the European Union, it enjoys express but restricted approval from the Environmental Protection Agency (EPA)

Only registered applicators can administer Paraquat upon the completion of an EPA-approved training course. Nevertheless, despite mandatory personal protective equipment (PPE) and other safety precautions, even licensed Paraquat users run the risk of sustaining potent Paraquat exposure. 

The most vulnerable populations for Paraquat exposure include farmhands and agricultural employees, but neighboring residents can run the risk of overexposure from herbicide drift, overspray, and runoff as well. 

In the short-term, Paraquat exposure may result in mouth and throat irritation and abdominal pain, but extended intervals may cause: 

Symptoms of Parkinson’s Disease from Paraquat Exposure

One of the most severe medical complications associated with Paraquat exposure is Parkinson’s Disease. The neurodegenerative and incurable disorder results in the degradation and death of important neurons in the brain. Over time, the subsequent decrease in dopamine levels can severely inhibit normal brain and bodily functions. 

Although there is not a definitive scientific consensus on the causes of Parkinson's disease, many researchers and physicians have concluded that both genetic and environmental factors impact risk levels. In the context of Paraquat litigation, plaintiffs assert that their exposure to the toxins in Paraquat contributed significantly to their subsequent diagnosis. 

Paraquat’s known potential to increase oxidative stress in both rodent and human test subjects may be positively linked to permanent cell damage in those parts of the brain most heavily impacted by Parkinson’s. In victims of Paraquat exposure, Parkinson’s Disease typically manifests in:

  • Mild motor impairments
  • Tremors
  • Imbalance
  • Postural disturbance
  • Muscular rigidity
  • Bradykinesia and akinesia
  • Speech impairment
  • Emotional and psychological changes

Paraquat Litigation Holds Manufacturers to Account

In recent years, the victims of Paraquat exposure have begun to file suit against two prominent manufacturers, Syngenta and Chevron Phillips Chemical Company LLC. Plaintiffs allege that their parkinson's diagnoses are causally linked to Paraquat inhalation or absorption and that the herbicide’s manufacturers misled the public about the safety of their products. 

In June 2021, the U.S. Judicial Panel on Multidistrict Litigation (JPML) granted select plaintiffs’ request to consolidate their cases for pretrial proceedings in a multidistrict litigation (MDL). The federal panel subsequently transferred the MDL to the U.S. District Court for the Southern District of Illinois and appointed Judge Nancy Rosenstengel as presiding magistrate. 

The Centrality of Expert Testimony in Paraquat Lawsuits 

Aside from procedural disputes between the defense and prosecution, the ongoing Paraquat litigation hinges on the scientific evidence parties adduce. Syngenta and Chevron have continually denied the connection between PQ exposure and Parkinson’s Disease, and frequently cite the inconclusiveness of clinical research. 

The Environmental Protection Agency (EPA) has partially corroborated their argument by renewing but restricting Paraquat’s sale and application on a 15-year license, in October 2020. Nonetheless, the court-approved plaintiffs’ counsel undertook a rigorous campaign of evidentiary collection, and introduced a series of persuasive, peer-reviewed studies suggesting a positive Paraquat-Parkinson's disease correlation. 

For example, a 2011 study from Environmental Health Perspectives concluded that “PD was positively associated with [paraquat or rotenone]” on account of their tendency to increase oxidative stress and inhibit the mitochondrial complex, respectively. Another study published in Movement Disorders concluded that those who lack the crucial GSTTI gene were especially vulnerable to PQ-induced Parkinson’s Disease. 

Internal Documents Reveal Manufacturers Knew of Inherent Paraquat Health Risks

Throughout the course of the discovery process, the defense and their affiliates sought to frustrate efforts to disclose incriminating evidence. The crossfire came to a head in February 2023 after Syngenta’s consulting firm attempted to evade a subpoena from the court. 

Exponent Inc. likely served an important role in Syngenta’s efforts to conduct internal and confidential research into the health hazards of Paraquat and the company’s liabilities. When considered alongside previously undisclosed documentation from the 1970s revealing Syngenta’s awareness of Paraquat’s risks, the controversy damaged the credibility of the herbicide manufacturer’s defense.  

Pennsylvania Paraquat Class Action Lawsuit

Although the Paraquat MDL contains over 6,000 plaintiffs, it is not the exclusive litigation challenging the irresponsible business practices of Paraquat producers and distributors. In April 2023, a Pennsylvanian court authorized a Paraquat class action lawsuit, involving hundreds of injured members. 

In contrast to multidistrict litigation, class action lawsuits result in the establishment of a class of injured plaintiffs, on whose behalf a single or several representative cases are tried. Class action certifications last for the entirety of legal proceedings and may advance in both state and federal courts. 

Common Damages in Parkinson’s Herbicide Lawsuits 

Exposure to Paraquat can result in a series of serious health complications, which may alter or even threaten victims’ lives. Alongside the emotional and mental stress these severe conditions can cause, they also decrease an individual’s ability to work and jeopardize their financial stability. 

Fortunately, plaintiffs who have suffered high levels of Paraquat exposure and subsequently developed Parkinson’s Disease may be entitled to financial compensation for damages, such as: 

  • Medical costs – past, present, and future
  • Lost wages and income 
  • Transportation costs
  • Physical therapy expenses
  • Mental anguish
  • Pain and suffering
  • Loss of consortium 

In order to determine the precise compensation figure to which you may be entitled, it is of paramount importance to speak with a qualified Paraquat lawyer. 

Contact an Experienced Herbicide Lawyer for Your Paraquat Lawsuit

Syngenta and Chevron Phillips Chemical Company LP prioritized the bottom line over public health. They understood the risks inherent in the application of and exposure to Paraquat but failed to inform users of potential complications and conditions associated with their use. 

Now that they are being held to account, the legal team at LLN is on standby to offer you and your loved ones counsel, support, and results. Our experienced Paraquat lawyers are intimately familiar with the intricacies of enrolling in an MDL, and provide free consultations to prospective clients to inform them of their rights. 

For more information about the eligibility of your claim or the compensation to which you may be entitled, consider contacting us today. 


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