Essential herbicide, but at what cost? Paraquat remains in US despite bans elsewhere

The number of nations where paraquat, an agricultural herbicide, is allowed to be used continues to dwindle, yet paraquat continues to receive stamps of approval from federal regulators in the United States.

"Contrary to these dozens of countries, which have looked at the exact same data and have found that paraquat is too dangerous [and] too toxic to continue using, the United States Environmental Protection Agency reached the exact opposite conclusion," said Jonathan Kalmuss-Katz, a senior attorney with Earthjustice, a non-profit environmental law firm.

Paraquat, which is often distributed under the name Gramoxone in the U.S. by Syngenta, is a restricted use herbicide known for its effectiveness in killing weeds.

Farmers across the country are only allowed to use paraquat if they have been trained and certified, and when applying it to farmland, they are told to wear protective gear and not ingest any amount of the herbicide due to its toxicity.

Frank Garcia didn't think twice about using paraquat on his Arizona farm in the late 1970s and early 1980s. He says that he got the necessary certification to use paraquat, but does not remember whether he or his wife Maria wore respirators when using the herbicide.

"You could see the results in a few hours," Garcia said. "In a day or two, [the weeds] would be shriveled up pretty well."

Decades later, Maria Garcia is battling Parkinson's disease, and she believes it's because she was exposed to paraquat during her time on the farm. She is one of more than 4,000 people who have sued Syngenta and Chevron, alleging negligence and failure to warn of a product liability.

Syngenta rejects these concerns, telling ABC News, "In short, the hypothesis that paraquat causes Parkinson's is not accepted in the medical community or peer-reviewed science, nor has it been accepted at any time in the past."

'They continue to sell it here'

The use of paraquat tripled in the U.S. between 2008 and 2018, with estimates from the U.S. Geological Survey showing that in 2018, the use of the herbicide was particularly common in areas such as California's Central Valley, Iowa and the Mississippi River Valley.

In 2019, Thailand issued a ban on paraquat, with Brazil, Chile, Malaysia, Peru and Taiwan each following with various prohibitions. China also banned the domestic use of paraquat, despite a state-owned Chinese chemical company acquiring Syngenta in a record $43 billion deal in 2017.

"The Chinese government essentially owns Syngenta, but doesn't use [paraquat] in their own country," Peter Flowers, co-lead counsel in the multidistrict litigation against Syngenta and Chevron involving more than 4,000 plaintiffs, told ABC News.

"They continue to sell it here," he continued. "We as Americans should be outraged by this."

Paraquat bans now apply to more than 50 countries, an ABC News analysis found.

To use paraquat products like Gramoxone, the EPA says that Americans must be certified pesticide applicators and complete an hour-long online safety training every three years.

"EPA's assumption that existing regulations would be sufficient to protect people is just not grounded in reality and not supported by science," said Kalmuss-Katz.

Syngenta says that Gramoxone does not pose a danger when used properly.

Chevron, which distributed Gramoxone in the U.S. between 1966 and 1986 before ceasing its involvement in the paraquat market, has also denied liability. They told ABC News in a statement that they quit selling paraquat for commercial reasons due to increased competition, not health concerns.

"To this day, and despite hundreds of studies being conducted in the past 20 or so years, a causal link between Paraquat and Parkinson's disease has not been established," Chevron's statement said.

'This would be really bad for them'

The EPA has insisted that its most recent thorough review of scientific studies on paraquat has found no clear link between the herbicide and Parkinson's.

Both the agency and Syngenta have pointed to a 2020 Agricultural Health Study sponsored in part by the National Institute of Health, which found "that there was no evidence of an association between paraquat exposure and Parkinson's disease."

But in their petition, Earthjustice argued that the EPA "misinterpreted the evidence" when they dismissed the connection between paraquat and Parkinson's disease, and that their risk assessment was "flawed" and "one-sided," which could leave more people "likely to develop Parkinson's disease."

Dr. Deborah Cory-Slechta, a widely respected University of Rochester neurotoxicologist, conducted several of her own paraquat studies on mice and reached a conclusion that was different from what the EPA found.

"We saw things that were convincing to us that paraquat could indeed be a risk factor for Parkinson's disease," Cory-Slechta told ABC News.

Cory-Slechta's work examining what effect paraquat has on the brains of mice is frequently cited as evidence suggesting a link between paraquat and Parkinson's.

"The human studies … show links between paraquat and Parkinson's disease over and over again," she said. "The animal studies continue to show those links including the loss of dopamine neurons, so you have a correspondence between the human and the animal studies that's very compelling."

Cory-Slechta was being considered by the EPA as a potential candidate nearly 20 years ago for a scientific advisory panel regarding pesticides, but 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, said the internal Syngenta communications she obtained showed that Syngenta did not want that to happen.

"Syngenta got wind of this and realized that this would be really bad for them," Gillam said, pointing to a 2005 email in which Syngenta asked "what action can be taken" to keep Cory-Slechta off the EPA panel. "You can see through the emails how they develop this plan that they want to convince the EPA to kick her off or to not appoint her to any of their panels."

Syngenta maintains that it "acted appropriately with regard to Dr. Cory-Slechta."

In other internal communications obtained by Gillam, the company asked industry lobbying group CropLife America to, “in such a way that they cannot be attributed to Syngenta,” tell the EPA that Cory-Slechta was unwilling to "enter into objective scientific debate with industry regarding her data."

When ABC News reached out to ask about Cory-Slechta, Syngenta said they continue to stand by this position.

"I think Syngenta's efforts are very similar to what I've seen over the years from many chemical companies whose efforts are to either discredit the science or to mitigate its potential impact," Cory-Slechta said.

Federal lobbying disclosures show CropLife America spent almost $2 million last year on lobbying efforts. Some of that money was associated with legislation like the Protect America's Children from Toxic Pesticides Act, which would ban pesticides like paraquat from the U.S.

CropLife America told ABC News that it "routinely represents our members by reflecting their views in our comments on these nominees, as we do on dozens of other regulatory matters on which EPA requests public comment."

A reconsideration by regulators

In 2021, the EPA issued an interim decision to allow for paraquat’s continued use in the U.S. for another 15 years while requiring additional safety precautions.

Since then, after being sued by Earthjustice, which is representing The Michael J. Fox Foundation and other organizations in this effort, the EPA said that they would reconsider their decision.

"Now [the] EPA has a chance to go back to fix the mistakes that it made during the prior risk evaluation, to reject Syngenta's interference and to provide the protections law requires," Kalmuss-Katz of Earthjustice said. "We're waiting to see whether [the] EPA lives up to that."

In the meantime, more than 2,300 miles away from EPA headquarters, each day continues to be a challenge for Maria Garcia as she copes with the effects of Parkinson's in her Arizona home.

Tricia, Maria's daughter-in-law, is hoping that the agency will take action.

"I would urge the EPA and any other decision makers to please ban this product from being used in the United States and save the lives of the future farmers," she said.