22
Nov
Paraquat, Parkinson’s, and Litigation: Chem Company Proffers Disinformation and Character Assassination
(Beyond Pesticides, November 22, 2024) With numerous campaigns at the state and federal level to ban the weed killer paraquat and nearly 6,000 individual lawsuits alleging exposure to it causes Parkinson’s disease (PD), U.S. Senator Cory Booker (D-NJ) and six Senators on October 31 called on the U.S. Environmental Protection (EPA) to ban the chemical. Citing that “[f]armworkers and rural residents are disproportionately exposed to paraquat,” the Senators’ letter to EPA stating that, “Paraquat has been linked to Parkinson’s disease, thyroid cancer, and other health harms such as kidney, liver, and respiratory damage, and reproductive harm, including neurodevelopmental impact on developing fetuses [and] [i]n rural areas, exposure to paraquat and other pesticides during pregnancy can increase the risk of leukemia.”
Most of the 6,000 cases against paraquat’s manufacturer, Syngenta, have been consolidated into Multi-District Litigation (MDL) in the U.S. District Court for the Southern District of Illinois. In April the MDL judge ousted the plaintiffs’ expert witness regarding causality, which resulted in the first five cases ready for trial being tossed out. The defendant sells paraquat globally and is doing everything it can, according to investigative news reports, to discredit any link between paraquat and Parkinson’s, including the use of misdirection, disinformation and character assassination.
A series of recent news reports have collectively dissected Syngenta’s malfeasance—and its power. These investigations include an October 2024 report by Evy Lewis of Investigate MidWest; a June 2023 report by Carey Gillam at The New Lede, including its documents archive; The Guardian’s October 2022 expose by Gillam and Aliya Uteuova; a March 2021 report by Crispin Dowler and Laurent Gaberell of Greenpeace’s Unearthed; and U.S. Right to Know’s series on paraquat.
See also Beyond Pesticides’ coverage of paraquat health hazards, regulation and litigation, as well as our work on conflicts of interest in science, attacks on scientists such as Tyrone Hayes, PhD, and industry influence on federal agencies.
The MDL expert witness conflict is a perfect example of industry’s self-protective gyrations. The plaintiffs’ sole causation expert was Martin Wells, PhD, a Cornell University statistician and epidemiologist. Dr. Wells found in a meta-analysis that, in study participants occupationally exposed to paraquat, the incidence of Parkinson’s nearly tripled. The court found that Dr. Wells’ work was methodologically suspect and that, since his analysis was not generally accepted by his peers, he must be isolated from the scientific community—a marker of unreliability, according to a legal backgrounder by the conservative Washington Legal Foundation. Judges have wide latitude to determine the “reliability” of expert testimony under the “Daubert Standard.”
About 10 million pounds of paraquat a year are used in the U.S., mostly to control weeds in soy, corn, cotton, peanuts, almonds, grapes and other crops. No residential use is approved, and more than 60 countries have banned paraquat. Concern has been mounting for decades based on its extreme acute toxicity and accumulating evidence of its neurological hazards even in lower chronic exposures. In July 2021, EPA conducted a reregistration review and decided to leave paraquat on the market with further restrictions, saying “the Agency concluded that the weight of evidence was insufficient to link paraquat exposure from pesticidal use of U.S. registered products to PD in humans.” Its most recent action, taken only under pressure from environmental groups, is to reexamine paraquat’s toxicity with results due in 2025.
But paraquat’s life is much longer than the suits filed in 2021 and afterwards, as is the knowledge that paraquat damages the nervous system of animals. In a breathtaking example of scientific malpractice, the company that discovered paraquat’s herbicidal talents in 1955—Imperial Chemical Industries (ICI)—simply declared, as was also done in the case of the herbicide glyphosate, that something that kills plants would have no effect on animals. (Syngenta, the successor to ICI, is now owned by Sinochem, a Chinese state-owned company.) The industry has known for decades that paraquat kills plants via oxidative stress, a process common to bacteria, fungi and animals as well.
The history of pesticides lays bare the mistake made by governments to leave scientific research to the entities that would be profiting from the product. Despite the assertion of no harm to animals, an ICI scientist wrote in an internal 1958 memo that dipyridyl, an active ingredient in paraquat (which is marketed in the U.S. as Gramoxone), had “moderate toxicity mainly by affecting the central nervous system” and could be absorbed through the skin. Hypocrisy is a powerful political tool.
The art of character assassination is well developed at Syngenta. Ray Dorsey, MD is a neurologist known for his proposal, analyzed by Beyond Pesticides here, that two types of Parkinson’s may be the same disease caused by chemical exposures moving through different body systems to the brain. Dorsey was dragged into the MDL by Syngenta in a bizarre and intrusive attempt at discrediting him.
Dr. Dorsey had declined to be an expert witness, but Syngenta served him with a discovery subpoena to produce documents used to prepare a co-written opinion piece in Movement Disorders, a publication of the International Parkinson and Movement Disorder Society. The piece asserted that paraquat causes Parkinson’s. Dr. Dorsey cited Syngenta’s half-century campaign to suppress evidence of paraquat’s neurological effects. He called Syngenta’s behavior “agnotology,” or “the deliberate production of ignorance.” His discussion was based on the The Guardian investigation. Syngenta attacked Dr. Dorsey simply because his opinion piece, supported by scientific evidence and investigative journalism, had attracted a lot of public attention. Apparently, Syngenta considered this unfair. The court sided with Dr. Dorsey. But Syngenta still won the skirmish in convincing the court to exclude Dr. Wells, leaving the defendants without a causation expert.
The Guardian exposé also revealed Syngenta’s extensive character assassination of neurotoxicologist Deborah Cory-Slechta, PhD, whose research has shown that paraquat crosses the blood-brain barrier and, when inhaled, travels up the nose to the olfactory bulb, whence it is distributed throughout the brain. But Syngenta knew paraquat reached the brain much earlier and might have lingering effects there. According to Investigate MidWest, “In 2008, Syngenta internally re-evaluated paraquat’s safety. In its report, it listed several ‘major sources of uncertainty,’ including the question of how long paraquat remained in the brain and the possibility the braincell death caused by paraquat exposure could progress even without further exposure.”
All these actions recall Syngenta’s scurrilous attacks on Tyrone Hayes, PhD, the University of California Berkeley researcher who demonstrated atrazine’s endocrine disrupting effects. As detailed in a 2014 New Yorker article by Rachel Aviv, Syngenta went so far in the late 1990s to spread the rumor that Dr. Hayes was mentally unstable. Eventually the company mounted an all-out and largely successful (at least temporarily) destruction of Dr. Hayes’ academic and public reputations. See Beyond Pesticides Daily News analyzing the Hayes case and Syngenta’s misinformation campaign against a class action suit. Dr. Hayes delivered the keynote speech at Beyond Pesticides’ 31st National Pesticide Forum.
EPA focuses only on toxicological tests provided by the manufacturer, which are outmoded and fail to capture the real effects of pesticides on the biosphere. Standard tests usually do not include examination of brain tissue in animal models except to assess developmental effects in offspring. Thus, Syngenta has been able to ignore evidence such as that cited in the Investigate MidWest story in which a Japanese woman died of paraquat poisoning in 1968 and an autopsy subsequently found paraquat in her brain. An ICI doctor wrote that the levels found were “rather higher than we would have expected, particularly in the brain, considering the relatively small quantity that was taken.”
The Guardian investigation cited the case of a farmworker showing degenerative changes in the brain after paraquat exposure. And in an especially scurrilous attack, a completely unqualified columnist at the American Council on Science and Health, an industry supported group, wrote last year that the MDL cases are unfounded because “paraquat probably can’t cross the blood-brain barrier efficiently enough to cause the neurological damage at the root of PD.” His statement is based on a 2021 “review of reviews” in NeuroToxicology by Douglas Weed, MD, PhD, a consultant who has worked with industry partisans to deny glyphosate’s carcinogenicity.
According to Investigate MidWest, both EPA and Syngenta have argued that animal studies on paraquat do not apply to workers using paraquat because the animal studies involve injecting huge amounts into the animals and humans are more likely to inhale, lick their lips, or have dermal exposure, “usually in very small quantities.”
The logic of toxicology testing is incredibly skewed. This argument shows that the EPA test requirements are tailored to acute exposures, not chronic ones. It also assumes inhalation is not a relevant exposure route, which is completely inaccurate. Further, one has to ask why, if the high-dose tests are irrelevant, they are being used to decide whether human health effects are plausible. In fact, in the Wells ruling, the MDL judge noted that both parties had warned against relying on animal studies to determine human causes of health effects. At the same time, however, the industry relies on arguments that denigrate human epidemiology as unreliable. The end result is the neutralization of the only methods available to enlighten the issue. Why the court does not recognize this double-dealing is unclear, especially given that evidence produced in the litigation—easily available to the judge—demonstrates how much deception and personal attack Syngenta and other pesticide companies routinely engage in.
In the words of a 2006 Lancet commentary on developmental toxicology by environmental health experts Philippe Grandjean, MD and Philip Landrigan, MD, “The two main impediments to prevention of neurodevelopmental deficits of chemical origin are the great gaps in testing chemicals for developmental neurotoxicity and the high level of proof required for regulation.” Eighteen years later these obstacles remain. Syngenta’s concerted disinformation, deceptive science and character assassinations are still working. Citizen pressure must force EPA to bring its regulatory practices into alignment with modern, ethical, and transparent science. Courts would likely then follow suit.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources:
Syngenta spent decades attempting to quiet health concerns about its profitable herbicide
by Evy Lewis, Investigate Midwest
October 23, 2024
https://investigatemidwest.org/2024/10/23/herbicide-paraquat-sygenta-legal-troubles-parkinsons-disease-health-claims-lawsuits
The Paraquat Papers: How Syngenta’s bad science helped keep the world’s deadliest weedkiller on the market
by Crispin Dowler and Laurent Gaberell
Greenpeace Unearthed
March 24, 2021
https://unearthed.greenpeace.org/2021/03/24/paraquat-papers-syngenta-toxic-pesticide-gramoxone/
details international paraquat overdose problems and syngenta’s refusal to include an adequate emetic in its formulations
Syngenta’s “SWAT” team- Internal files reveal secret strategies to influence science
by Carey Gillam
The New Lede
https://www.thenewlede.org/2023/06/syngentas-swat-team-internal-files-reveal-secret-strategies-to-influence-science/
Assault on Science what is getting in the way of using science to protect health and the environment?
Beyond Pesticides – Pesticides and You, Winter 2017–2018
https://www.beyondpesticides.org/assets/media/documents/infoservices/pesticidesandyou/documents/TyroneHayesProtectingLife.pdf
Beyond Pesticides Urges Ban of Weed Killer Paraquat Using Same Criteria Used in the Landmark Dacthal Ban
Beyond Pesticides, October 1, 2024
https://beyondpesticides.org/dailynewsblog/2024/10/beyond-pesticides-urges-ban-of-weed-killer-paraquat-using-same-criteria-used-in-the-landmark-dacthal-ban/
Biden EPA Reapproves Paraquat with Weaker Protections than Trump Administration Proposed
Beyond Pesticides, August 10, 2021
https://beyondpesticides.org/dailynewsblog/2021/08/biden-epa-reapproves-paraquat-with-weaker-protections-than-trump-administration-proposed/
California Bill Would Ban Deadly Weedkiller, Paraquat, Linked to Parkinson’s Disease in Face of EPA Inaction
Beyond Pesticides, April 16, 2024
https://beyondpesticides.org/dailynewsblog/2024/04/california-bill-would-ban-deadly-weedkiller-paraquat-linked-to-parkinsons-disease-in-face-of-epa-inaction/
Parkinson’s Disease Explodes as Researchers Find Connection to Pesticide Exposure and Genes
Beyond Pesticides, May 3, 2024
https://beyondpesticides.org/dailynewsblog/2024/05/parkinsons-disease-explodes-as-researchers-find-connection-to-pesticide-exposure-and-genes/
Research Links Parkinson’s and Lewy Body Disease with Chemical Effects on Brain and Gut
Beyond Pesticides, April 19, 2024
https://beyondpesticides.org/dailynewsblog/2024/04/research-links-parkinsons-and-lewy-body-disease-with-chemical-effects-on-brain-and-gut/
Uncertain Harvest: Examining the globe-spanning relationship of chemical companies, academics and regulators, and the powerful toxins and genetically modified seeds used to grow food in many parts of the world.
Scientists Loved and Loathed by an Agrochemical Giant
by Danny Hakim
New York Times, December 31, 2016
https://www.nytimes.com/2016/12/31/business/scientists-loved-and-loathed-by-syngenta-an-agrochemical-giant.html
New Report Showcases Atrazine Manufacturer’s Efforts to Discredit Critics
Beyond Pesticides, June 21, 2013
https://beyondpesticides.org/dailynewsblog/2013/06/new-report-showcases-atrazine-manufacturers-efforts-to-discredit-critics/
