Revealed: the undisclosed safety data emerging as weedkiller maker faces Parkinson’s lawsuits in US

Sweden started ringing the alarm doorbell much than 20 years ago, calling for a prohibition connected the weedkilling chemic paraquat successful 2004. One by one, dozens of different countries did the aforesaid arsenic grounds of paraquat risks to quality wellness mounted. Even the Chinese government, which owns the longtime paraquat shaper Syngenta, halted home usage of the pesticide a decennary agone aft conducting its ain studies connected paraquat information and uncovering troubling results.

In the US, 2 states – Vermont and California – person precocious besides banned paraquat, citing risks that see an relation betwixt paraquat and Parkinson’s illness shown successful years of technological research. And California regulators announced successful August that paraquat makers voluntarily agreed to halt selling the chemic aft the authorities identified wellness concerns successful transportation with its usage successful caller research. Several national lawmakers person pushed for a nationwide ban.

Yet amid the planetary unreality of concern, the US Environmental Protection Agency (EPA) continues to greenlight paraquat usage connected millions of acres, and has downplayed scientific findings linking paraquat to Parkinson’s, an incurable encephalon disease. The bureau said successful June it would clasp a circular array implicit the summertime to re-examine the “safety challenges” associated with paraquat. But nary specified lawsuit has yet been held oregon scheduled.

Now, clues to however and wherefore the US remains 1 of the world’s past ample markets for wide paraquat usage are coming to airy done troves of interior Syngenta records precocious revealed done litigation.

The records amusement that arsenic paraquat markets astir the satellite started crumbling implicit concerns for nationalist health, Syngenta, a Swiss-headquartered multinational, fought to support a choky clasp connected the US market, wherever usage of paraquat nearly tripled betwixt 2000 and 2018, a clip play erstwhile dozens of different countries were banning paraquat.

Internal firm records, depositions and different records amusement that earlier and during this clip frame, Syngenta did not stock definite interior information and different accusation with the EPA regarding paraquat wellness effects and risks contempt national ineligible requirements for companies to study accusation astir “unreasonable adverse effects” of their products.

Among the information not shared by Syngenta were analyses of however rapidly the chemic could permeate untreated clothing; however accelerated it could sorb into an applicator’s tegument and bloodstream. The institution besides did not stock immoderate accusation astir however mixing paraquat with surfactants increases the chemical’s absorption. Surfactants are additives commonly utilized by workplace workers to assistance herbicides flooded the waxy, water-repellent aboveground of their leaves. Certain accusation demonstrating dire risks to the encephalon from vulnerability was besides not shared with the EPA.

In contrast, the institution focused connected processing and promoting subject showing paraquat information that it could stock with regulators, including 1 published successful 2016 that institution insiders noted would beryllium “invaluable successful supporting our work”.

In 2022 and 2023, the New Lede and the Guardian obtained and revealed a set of interior firm records showing that Syngenta and its predecessor firm entities utilized an array of concealed tactics for decades to downplay and discredit subject linking what the institution called its “blockbuster” weedkiller to Parkinson’s and different chronic wellness issues.

The recently released files, totaling astir 3,700 pages, supply much insights into the company’s handling of paraquat concerns, arsenic good arsenic aggregate examples of accusation Syngenta did not stock with the EPA. The records were submitted to a Pennsylvania authorities tribunal wherever cases person been filed by radical with Parkinson’s alleging that they developed the illness from vulnerability to paraquat products. Earlier this period the underlying suit successful which the documents were filed was dismissed by the justice owed to the plaintiff not having capable impervious of vulnerability to paraquat; however, determination are thousands much progressive cases pending astir the country.

In the look of the ongoing litigation, which has already outgo the company astatine slightest $187m successful a 2021 settlement and an undisclosed further magnitude for additional settlements since then, Syngenta announced earlier this twelvemonth it would halt each planetary accumulation of paraquat.

Asked astir the recently disclosed US tribunal documents, Syngenta said it has ne'er knowingly failed to supply regulators with immoderate applicable and required information. The institution has agelong maintained that determination is nary existent nexus betwixt paraquat and Parkinson’s disease, and that its determination to halt selling was purely based connected marketplace factors. The settlements see nary admittance of liability.

Other suppliers proceed to merchantability successful the US arsenic the EPA maintains determination is no “clear link” betwixt paraquat vulnerability from regular usage and “adverse wellness outcomes specified arsenic Parkinson’s illness and cancer”.

Empty containers of herbicides astatine a workplace successful San José de la Esquina, Argentina, connected 16 January 2023. Photograph: Bloomberg/Getty Images

Critics accidental the communicative of paraquat is simply a lawsuit survey successful the failures and frailties of the EPA and a strategy that does much to support firm profits than user health. And critics enactment that revelations that the institution failed to stock definite information with the EPA are peculiarly concerning now, coming conscionable months aft the US ultimate tribunal issued a ruling declaring the EPA arsenic the pre-emptive authority for determining erstwhile a pesticide merchandise needs to see a peculiar wellness warning.

“When the pesticides companies cognize from their ain studies that their pesticides are harmful and don’t archer the nationalist oregon regulators, past they are knowingly contributing to radical getting sick and dying,” said Tracey Woodruff, a prof of epidemiology and colonisation wellness astatine the Stanford University School of Medicine.

When asked astir Woodruff’s comment, Syngenta rejected the claims and said it takes the information of its products precise seriously.

When asked astir the omissions of information, the EPA said successful a connection that it “cannot speculate connected however this further accusation would interaction EPA’s assessment”, but noted it has based its paraquat assessments connected an “extensive database of information”.

The bureau noted that the paraquat reappraisal is ongoing.

“If accusation exists that has not been submitted to EPA, EPA wants it truthful that immoderate protections developed are rooted successful golden modular subject and reflective of the afloat beingness of data,” the national bureau said.

The bureau said that companies indispensable taxable accusation “regarding immoderate unexpected oregon unreasonable adverse effects resulting from their product’s usage to EPA. Failure to comply is simply a nonstop usurpation of national law,” the bureau said.

‘Bad news’

The cardinal instrumentality regulating pesticides – including herbicides – the Federal Insecticide, Fungicide and Rodenticide Act (Fifra), requires that a institution holding a pesticide registration indispensable taxable “factual accusation regarding unreasonable adverse effects” to the EPA adjacent aft a pesticide has been approved and is connected the market.

EPA guidance connected however to construe the requirements states that accusation indispensable beryllium submitted if “the registrant knows, oregon should reasonably know, that the information, unsocial oregon successful conjunction with different information, mightiness rise concerns astir the continued registration of a pesticide oregon astir the due presumption and conditions of registration of a pesticide”.

Yet Syngenta acknowledged successful discovery that arsenic of the day of that papers – January 2025 – it had nary grounds of providing the EPA with a agelong database of reports and probe that it possessed pertaining to paraquat and imaginable wellness impacts.

When asked by the New Lede and the Guardian astir galore tribunal records detailing information not shared with the EPA, the institution said nary of it was applicable to the US marketplace oregon to EPA oversight and would not person changed the regulatory presumption of paraquat. The institution said it has ne'er “deliberately withheld pertinent accusation from the US EPA, oregon immoderate different regulatory authorization astir the world” and has “always afloat complied with each EPA information requests and provided applicable survey data, successful enactment with EPA’s regulatory requirements”.

There are galore examples of accusation that Syngenta developed oregon accessed but did not springiness to the EPA, according to the tribunal documents and interior institution files. Here are a few:

• Information astir concerns with surfactants, which workplace workers premix into weedkillers to assistance absorption connected plants. Labels connected the company’s US products person agelong recommended that users adhd surfactants anterior to spraying paraquat to marque it much effective. But astatine slightest since the 1970s, the institution has had accusation that paraquat could go much toxic erstwhile mixed with surfactants. Company files amusement worries astir “increased toxicity” erstwhile surfactants were added to paraquat and see studies showing the imaginable for accrued absorption, including done tegument and nasal membranes. The institution did not stock astatine slightest immoderate of those findings with the EPA, according to deposition grounds and Syngenta’s tribunal admissions. Syngenta denied successful the tribunal filings that surfactants volition “normally summation the absorption of paraquat and hence summation its toxicity”. And a institution spokesperson said erstwhile asked astir the surfactant concerns that Syngenta conducted galore studies that recovered nary harmful effects connected the tense system. The surfactant utilized successful Syngenta’s Gramoxone merchandise was “specifically selected not to accelerate epidermal penetration”, the spokesperson said. The institution additionally said galore studies amusement surfactants person “no important interaction connected dermal absorption of paraquat”.

• Data showing that Syngenta’s Gramoxone paraquat merchandise “almost immediately” penetrated fabric and different covering materials, including Tyvek materials commonly utilized successful protective apparel. Though the survey was done successful 1985, Gramoxone labels person stated for years that users tin deterioration a “long-sleeved garment and agelong pants”. When asked astir wherefore the survey results were not fixed to the EPA, Syngenta said that the merchandise was not registered successful the US, the results lone confirmed accusation already known, and labels astatine that clip successful the US already recommended waterproof footwear and clothing.

• A 1988 investigation of paraquat absorption successful the urine and humor of radical spraying the pesticide implicit 3 days that recovered “an unexpected number” of affirmative urine tests. A fig of workers had paraquat successful their plasma arsenic well. Company notes stated that the detection of paraquat successful plasma “was the archetypal clip it had been observed” and that it could subordinate to “a occupation that whitethorn originate with the EPA”. When asked astir the analysis, the institution said the concern was not applicable to the usage of paraquat products successful the US for assorted reasons, including the information that the US required idiosyncratic protective equipment.

• In 2007, different valuation of paraquat successful the urine of workers spraying the chemic brought “bad news”. Email correspondence shows 2 of the tiny radical of sprayers showed levels of paraquat that vastly exceeded “acceptable relation vulnerability levels” (AOEL). “This is atrocious quality whichever mode you look astatine it,” a Syngenta idiosyncratic wrote successful an internal email successful June 2007. When asked astir the evaluation, Syngenta said astir paraquat absorbed into the assemblage is rapidly excreted done urine and truthful is not a “regulatory oregon toxicological concern”. The institution besides said that the AOEL information progressive operators who were not complying with paraquat information measures, and the institution said the precocious exposures were “not typical of mean paraquat use”.

In its defense, Syngenta notes successful the aforesaid tribunal filing that the EPA has “never cited oregon sanctioned Syngenta for failing to comply” with its disclosure obligations with respect to paraquat. And the institution said for each lawsuit of not sharing thing with the agency, determination were different factors and findings negating oregon reducing the value of the information. It besides said that EPA guidance regarding institution requirements nether the Federal Insecticide, Fungicide and Rodenticide Act had “evolved”, and the institution had followed “processes designed to comply with its evolving obligations”.

The institution said claims that it did not supply regulators with due accusation are “inaccurate and misleading”.

‘Brush speech 10 years of research’

In the US, paraquat is often utilized by farmers to power weeds earlier planting their crops and to adust retired crops for harvest. It is utilized successful orchards, wheat fields, pastures wherever livestock graze, fabric fields and elsewhere. Farmers person been assured by Syngenta, which brought paraquat to the marketplace successful the 1960s done a firm predecessor, that determination is nary credible grounds of a transportation betwixt the illness and its weedkiller.

But galore technological studies person recovered that paraquat damages cells successful the encephalon successful ways that tin pb to Parkinson’s. Concerns accelerated successful the 2000s arsenic respective researchers published studies supporting specified a link.

By 2003 the institution was noting the rising outer unit connected paraquat and acceptable a extremity to “raise the level of proactive regulatory defence of paraquat globally”, portion noting that the US was a starring marketplace for its Gramoxone brand. Syngenta’s firm run to support and beforehand paraquat usage past accelerated alongside the subject indicating harm.

A large portion of the effort was the work of studies addressing the paraquat and Parkinson’s links recovered by extracurricular researchers. In 1 email attached to the tribunal filing , a Syngenta idiosyncratic wrote to a colleague, “what we privation to bash is brushwood speech 10 years of probe by others and regenerate it with our own”. The institution would “employ the champion radical to assistance us” and would request “impeccable data” arsenic good arsenic “a batch of luck”. It was important that Sygenta’s probe beryllium “dead coagulated airtight and self-contained”, and credible with the larger subject assemblage arsenic good arsenic “the justice and jurors”.

When asked astir the email, Syngenta said probe astatine the clip was mostly based connected definite types of rodent studies that had constricted relevance to quality exposure, and the institution was seeking to behaviour a acold much broad analysis.

The company’s interior documents bespeak that secrecy was a cardinal constituent of the campaign. In a 2007 email, institution officials discussed a request to minimize written connection connected an investigation of paraquat and Parkinson’s data. Even that connection itself should not beryllium shared successful writing, but should beryllium communicated “verbally” to staff.

And successful a 2008 email, institution scientists were warned against written discussions astir conducting definite studies and chided for penning that “a large nonsubjective of this programme is to trim the risk” that Syngenta mightiness suffer lawsuits brought by radical with Parkinson’s. “Please tin we telephone a halt to this correspondence,” a Syngenta enforcement wrote to the colleagues.

Bans span the globe

Sweden was among the archetypal countries to prohibition paraquat, and was a cardinal subordinate successful starring the European Union to yet prohibition the chemic crossed each subordinate countries successful 2007 amid concerns astir neurotoxicity and Parkinson’s.

In 2011, galore African countries, including Senegal and Côte d’Ivoire, besides banned paraquat. Since then, galore others person joined successful blocking usage of the pesticide. In each much than 70 countries person chosen to prohibition the chemical. And successful a 2022 report connected reducing Parkinson’s risks, the World Health Organization called for banning definite pesticides, including paraquat.

Brazil banned paraquat, citing the risk of Parkinson’s and concerns that the chemic whitethorn beryllium mutagenic, meaning it could origin imperishable mutations successful DNA.

One of the astir noteworthy bans was made by China, not lone the location to Syngenta ownership but besides a ample manufacturing hub for paraquat made by a scope of companies and exported to the US and elsewhere.

Unlike the EPA, which mostly relies connected information information that comes from the companies selling pesticides, China sought a much autarkic presumption arsenic concerns astir paraquat mounted. Deposition grounds unsealed and included successful the caller tribunal filings amusement that Syngenta was caught disconnected defender erstwhile the Chinese authorities commissioned its ain dermal and inhalation toxicity survey astatine a Chinese lab.

The information that China undertook the survey without Syngenta’s cognition was “alarming”, according to an interior institution email confirmed by Syngenta idiosyncratic Phil Botham successful the 2024 deposition. The EPA did not bash its ain specified studies, Botham testified successful the deposition.

China started a phase-out of paraquat successful 2012 and ultimately banned it domestically successful 2016 aft uncovering utmost toxicity risks done some routes of vulnerability and different wellness risks.

Even immoderate ample nutrient companies person agelong agone banned paraquat successful their proviso chain. Dole, an Irish multinational shaper of fruits and vegetables, started eradicating paraquat from its fields 19 years ago. A 2007 email betwixt Syngenta executives astir Dole’s determination notes a request to effort to “influence” Dole’s property merchandise connected the substance “to guarantee its not excessively damaging”.

Through it all, the US EPA has taken the presumption that paraquat is an important instrumentality for farmers and grounds astir superior chronic wellness impacts is lacking, though the bureau does restrict paraquat usage to certified applicators and has enactment limits connected however it tin beryllium applied to effort to trim inhalation and absorption done the skin. But the bureau inactive allows paraquat to beryllium sprayed from the entity connected workplace fields.

In its 2021 decision, the EPA said determination was insufficient grounds of links betwixt paraquat and Parkinson’s and besides insufficient grounds of a scope of different wellness problems. The “human wellness database for paraquat is considered complete”, the bureau said successful its decision.

Several wellness advocacy groups challenged the EPA’s determination successful court, starring the EPA to accidental it needed clip to “further see substantive issues”. Last November, the bureau asked paraquat manufacturers to supply further information connected paraquat volatilization to assistance recognize vulnerability risks to radical surviving beyond areas wherever paraquat is sprayed.

Lee Zeldin, the EPA administrator, speaks astatine the agency’s office connected 18 February 2025 successful Washington DC. Photograph: Kayla Bartkowski/Getty Images

The EPA administrator, Lee Zeldin, past made a connection connected societal media successful January this twelvemonth saying the bureau was making a determination to “freshly reassess” the information of paraquat arsenic portion of an effort to admit the “Make America steadfast again” (Maha) movement. But an EPA spokesperson contradicted Zeldin astatine the time, saying the head had been referring to the volatilization data.

Paraquat was a premier illustration of the weaknesses successful the existent regulatory system, said Ted Schettler, a erstwhile doc who serves arsenic subject manager for the Science and Environmental Health Network, a radical that advocates for precautionary wellness policies.

“[This situation] illustrates the nationalist wellness risks of allowing the US EPA to beryllium the sole arbiter of pesticide safety,” helium said. “Untold numbers of radical could person been prevented from processing Parkinson’s disease, not to notation different illnesses, if the bureau had done its occupation of protecting nationalist health.”

This communicative is co-published with the New Lede, a journalism task of the Environmental Working Group