Paraquat Pesticide
Parkinson's Lawsuit

A Particularly Toxic Herbicide

Although many herbicides have been linked to health risks and a variety of diseases, paraquat is considered “the deadliest pesticide on the market,” according to one agricultural health study, causing about 100 poisonings each year. Highly toxic to humans, one sip of paraquat can be fatal, resulting in death 70% of the time.

Due to its toxicity, the Environmental Protection Agency (EPA) has made paraquat a restricted use pesticide, which may only be used by certified and trained applicators. The Centers for Disease Control and Prevention (CDC) provides information and warnings about paraquat because it is “more toxic and presents a greater risk from exposure” than other pesticide products.

In addition to the immediate danger of poisoning, recent epidemiological studies have investigated the long-term health effects of paraquat on individuals exposed to the herbicide during the mixing, loading, and spraying of the product.

Responding to the weight of evidence demonstrating the severe public health dangers posed by paraquat,  the EU, China, and Brazil, three of the largest agricultural producers in the world, are phasing out the use of paraquat or have banned the product entirely to protect the lives of farmers. By contrast, the United States has only taken some mitigation measures to control the immediate poisoning risks of paraquat, such as requiring warning labels, training, and safer packaging. Although these efforts may reduce the number of tragic accidents associated with paraquat, they do little to address the long-term dangers associated with low-level exposure to paraquat and the possibility that the herbicide is an environmental risk factor for Parkinson’s Disease.

Parkinson’s Disease

Parkinson’s Disease is a degenerative brain disorder that causes tremors, rigidity, slow movements, impaired balance, and difficulties with walking. Over time, both motor and non-motor symptoms gradually worsen, making day-to-day life more difficult for those suffering from the disease and for their caregivers. Although both men and women can develop the disease, it affects about 50 percent more men than women. Parkinson’s Disease affects between 750,000 and 1 million Americans, and studies show that by 2030, an estimated 1.2 million Americans will be living with the disease.

Parkinson’s is caused by the degeneration of nerve cells in the substantia nigra, the part of the brain that controls movement.  When these nerve cells die or become impaired, they produce fewer dopamine neurons, a critically important chemical compound that the nervous system uses to send messages between nerve cells. Without sufficient dopamine, the body’s balance is disrupted, leading to the slowness of movement problems that are the trademark symptoms of Parkinson’s Disease. There is currently no cure available for the disease.

Researchers still do not know the precise cause of Parkinson’s Disease, though genetic factors, accelerated aging, and the environment may all play a role.  In recent years, scientific studies have connected the development of Parkinson’s Disease to environmental exposures, including frequency of exposure to pesticides like Paraquat.

Can Paraquat Exposure Cause Parkinsons Disease?

Over the last decade, scientists have achieved significant breakthroughs that demonstrate a clear link between exposure to Paraquat and the development of Parkinson’s Disease.

A 2011 study by the National Institute of Health (NIH), the Farming and Movement Evaluation (FAME) report, used data from the Agricultural Health Study to show that Paraquat users developed Parkinson’s disease approximately 2.5 times more frequently than others. In experimental models, paraquat causes oxidative stress, which is known to bring about the loss of dopaminergic neurons in brain cells associated with Parkinson’s Disease.  

The FAME findings were supported by a 2014 study on Environmental Toxins and Parkinson’s Disease, which found that participants who had sprayed paraquat were twice as likely to develop Parkinson’s Disease than the general population. 

In 2017, an additional study found a link between paraquat and Parkinson’s Disease, particularly in people with certain genetic traits.  The major finding of the study showed that exposure to paraquat causes DNA damage and weakens mitochondrial respiration, which is likely to increase the incidence of Parkinson’s Disease. 

Last year, responding to the EPA’s proposal to re-approve paraquat, fifty-two organizations representing farmers, public health and conservation advocates signed a letter urging the EPA to ban paraquat due to the serious risks it poses to farmworkers and those who live near farms where the pesticide is used. In recent months, the New York Times has highlighted the dangers and public health costs of paraquat, calling attention to studies that tie the chemical to the development of Parkinson’s Disease symptoms. At the same time, a new book written by some of the world’s top experts in Parkinson’s Disease studies identified exposure to paraquat as one of the key environmental risk factors for the disease and forcefully called upon the U.S. government to ban the pesticide.  

Nevertheless, despite mounting evidence of the long-term dangers of paraquat to public safety, the EPA issued a Proposed Interim Decision in October 2020 that would re-approve paraquat for use with some mitigation measures. For the time being, the use of paraquat remains legal in the United States, although bills have been introduced in Congress seeking to end all paraquat sales and use in the country.