'Burns me to a crisp': Farmers allege link between popular herbicide paraquat and Parkinson's disease

It is against the law to use paraquat in China, Switzerland, the United Kingdom and dozens of other countries. Many countries have banned the herbicide due to its extreme toxicity, while others have expressed concerns over the possible risk for Parkinson's disease.

Yet the herbicide, manufactured by a Swiss company that is owned by the Chinese state, is still widely used throughout the United States in part because it is a highly effective way to kill weeds.

The company, Syngenta, says that paraquat, which it produces under the name Gramoxone, "is safe for its intended and labelled use."

Clayton Tucholke, who used Gramoxone for years on his farm in LaBolt, South Dakota, and has since been diagnosed with Parkinson's disease, says otherwise.

"It should have been pulled, I think, you know, so it didn't happen to somebody else," Tucholke told ABC News.

A 76-year-old father and grandfather, Tucholke lived on his farm with his wife Denise, but as the symptoms of Parkinson's have worsened, he says he was forced to give up his career in agriculture and had to move to the nearby town of Milbank to be closer to medical professionals.

Daily tasks have become arduous for Tucholke, who now has to travel to physical therapy three times a week to slow the progression of his symptoms.

"This man was so independent," Denise Tucholke said. "And his independence has been taken from him, which is unfair."

The Tucholkes are among the more than 4,000 Americans who have filed lawsuits as part of a multi-district litigation against Syngenta, which currently manufactures Gramoxone, and Chevron, which distributed it in the U.S. from 1966 until 1986.

Although Syngenta and Chevron told ABC News that there is no scientific evidence that supports a causal link between paraquat and Parkinson's disease, the Tucholkes and other plaintiffs allege that such a link exists, arguing that Syngenta and Chevron knew or should have known that the herbicide could "cause severe neurological injuries."

"Our daughter and son-in-law are still farming. I think any time [a] chemical is applied to the fields that they have to use, they should know what's going to happen," Denise Tucholke said.

"All the generations that are coming up afterwards need to know," she said.

'You have to be careful where you spray'

Gramoxone was initially manufactured by Imperial Chemical Industries, a British company that eventually evolved alongside other firms into Syngenta, which in turn was acquired by the China National Chemical Corporation in 2017.

To the Tucholkes, paraquat was highly effective at removing weeds when they used it throughout the 1970s and 1980s. It even killed weeds that had developed resistance to other herbicides.

"[It] kills vegetation, doesn't matter what," Denise Tucholke said. "You don't want it to drift to crops. You have to be careful where you spray."

Frank Garcia, a retired farmer living in Arizona, says he and his family used paraquat for years as well. He says his family knew paraquat was highly toxic if swallowed, but added that they were not warned of possible effects that could come from other forms of exposure to the herbicide.

"They should've told us the consequences of this, and they didn't," Garcia said. "That just burns me to a crisp."

Like Clayton Tucholke, Garcia's wife Maria was also diagnosed with Parkinson's.

Paraquat containers include warnings that one sip of the product can kill, and the EPA cautions that there is no known antidote to this toxic substance. During training, those seeking certification are told to wear proper protective equipment, including respirators, when handling paraquat.

Aside from its immediate toxicity, some of the world's leading scientists believe that exposure to environmental toxins, including pesticides like paraquat, could be associated with an elevated risk of developing Parkinson's disease.

'Something that was really disturbing'

In their claims against Syngenta, the Tucholkes and Garcias say that paraquat products were not accompanied by proper warnings regarding its possible health effects, including developing Parkinson's disease as a result of exposure. Both families told ABC News that they did not remember if they wore respirators when they applied paraquat.

The lawsuits brought by the Tucholkes and Garcias are not the only ones that Syngenta and Chevron have faced over paraquat.

In 2017, they were sued by plaintiffs with Parkinson's disease. According to Syngeneta's financial statements, they settled a number of lawsuits for a combined $187.5 million in response to claims they said have no merit.

Carey Gillam, a contributor to The Guardian and the managing editor for The New Lede, an environmental news website supported by the Environmental Working Group, followed the trial.

She says she obtained thousands of pages of internal documents from the case when they were left outside her home; documents she alleges show that Syngenta and Chevron management have known about possible risks associated with paraquat for decades.

"The level of knowledge that they had so long ago was something that was really disturbing," Gillam said, adding that Chevron executives were "talking about the chronic effects possibly causing them legal problems back in the 1970s."

In 1974, the notes from a Chevron meeting involving several senior members from different departments show that they were discussing how state regulators were concerned about the "potential long term chronic effects of workers … breathing in low doses of paraquat from spray mist."

The files show that an attorney believed that there was "evidence now that paraquat could cause industrial injury" and that "Chevron could face suits totaling millions of dollars."

By 1985, a Chevron internal memo was flagging an article about how pesticides, including paraquat, "may be implicated" as a cause for Parkinson’s disease.

"We can hope that another chemical or cause will explain the correlation," the memo said, and that, "I trust that Chevron is watching this closely… and, perhaps, doing a little testing for the sake of its customers and stockholders."

The next year, Chevron stopped selling paraquat completely.

A Chevron spokesperson said in part in response to questions from ABC News that the company "met or exceeded all federal and state requirements for product-safety testing before and after release." They say that they stopped selling paraquat for commercial reasons, and not because of health concerns.

But paraquat continued to be a lucrative product for Syngenta, with one internal memo in 1985 noting that they depended on it as a "major product" and would do whatever possible to defend it.

"They wanted to develop sort of a counterattack, a counter-strategy," Gillam said. "They talk about developing scientific studies that they can use in their defense of paraquat. They talk about influencing strategies with regulators."

'Her quality of life is almost non-existent'

More than four decades since paraquat was used on their Arizona farm, Maria Garcia now has to rely on family members like her daughter-in-law Tricia to assist with everything from walking around the house to preparing meals, all while facing growing medical bills.

"Her quality of life is almost non-existent," Tricia Garcia said.

"We have great sympathy for the health issues faced by the plaintiffs and others suffering from the debilitating effects of Parkinson's disease," Syngenta told ABC News in a statement. "But it is important to note that paraquat is safe when used as directed."

The company claims it is being targeted by what it calls a "mass tort machine" of plaintiffs' lawyers.

"Syngenta will not sell a product if it is not safe for its intended use," the company continued. "Paraquat contributes less than 2% of total sales, and less than 2% of overall profit for Syngenta. But it is an important product for farmers in their quest to produce food for an increasingly populated world."

Frank Garcia disagrees. What's more, he says that he doesn't comprehend how regulators like the EPA, which just renewed paraquat's U.S. registration in 2021, can still allow it to be used.

The EPA strengthened safety requirements at the time, but has not found that paraquat is unsafe to use when those requirements are followed nor has the EPA found there is a link between Parkinson's and paraquat, prompting appeals from advocates.

"I can't understand [why] the United States does not ban this," Garcia said.