The world’s most controversial weedkiller has had its safety approval vacated by a court, withdrawn by the regulator, and challenged by over a hundred and eighty thousand lawsuits — and you can still buy it this weekend.
Here’s what that tells us about how regulators decide what’s safe.
Walk into any garden centre or supermarket in New Zealand and you can pick up a glyphosate-based weedkiller. The label will tell you it kills weeds. It will not tell you it causes cancer.
The same is true in the United States — though there, Bayer began replacing glyphosate in consumer Roundup products in 2023, after the lawsuits became too expensive. Some researchers have argued that the replacement herbicides also raise important toxicological questions and should not automatically be assumed to be safer. The agricultural version — the one sprayed on the crops — still contains glyphosate. It is still legal. The US Environmental Protection Agency says it is safe.
So does New Zealand’s EPA.
But this story is less about whether glyphosate is safe than about something more fundamental: how regulators decide what “safe” means — and what happens when courts, juries, and independent scientists disagree.
How the US EPA’s Glyphosate Safety Approval Was Vacated by the Court
Glyphosate has been registered as a pesticide in the US since 1974. For most of those fifty years, it was uncontroversial. Then, in 2015, the World Health Organisation’s cancer research arm — the International Agency for Research on Cancer (IARC) — classified it as “probably carcinogenic to humans.”
That single word — probably — triggered more than a hundred thousand lawsuits.
In 2020, the US EPA published a formal Interim Registration Review Decision concluding that glyphosate was “not likely to be carcinogenic to humans.” A month later, the decision was challenged in court. In June 2022, the US Court of Appeals for the Ninth Circuit vacated the human health portion of the decision entirely, finding EPA’s analysis insufficient and its obligations under the Endangered Species Act unmet.
The EPA couldn’t meet a court-imposed October 2022 deadline to fix the ecological portion either. And so, in September 2022, it withdrew the decision altogether.
Here’s the part that surprises people: glyphosate stayed on shelves through all of this.
The EPA was explicit: “Pesticide products containing glyphosate continue to remain on the market and be used according to the product label and are unaffected by this action.”
The withdrawal of a safety decision doesn’t remove the product. In American pesticide law, the default is legal. Prohibition requires a separate, affirmative act. Regulatory chaos — even chaos that ends in a court-ordered vacatur of the agency’s own findings — does not disrupt commerce.
Why the EPA Says Glyphosate Is Safe While the WHO’s Cancer Agency Says Otherwise
To understand why regulators have reached different conclusions, it helps to understand what each body was actually asking.
The EPA’s job, under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), is a cost-benefit question: do the risks of this pesticide, given how people realistically encounter it, outweigh its benefits? It’s not asking whether glyphosate could harm someone under any circumstances. It’s asking whether it’s unreasonably harmful at normal exposure levels.
IARC’s job is different. It asks whether a substance is capable of causing cancer — a hazard question, not a risk question. IARC is not a regulator and does not set policy. It identifies hazards. The two approaches will sometimes produce different headlines from the same evidence.
The agencies also used different datasets. The EPA reviewed fifteen animal carcinogenicity studies; IARC reviewed eight. Critically, the EPA’s evidence base included unpublished studies submitted by manufacturers to support product registration — data IARC didn’t consider.
Critics have pointed out that industry-funded studies submitted by the registrant might not be the most disinterested evidence base. Regulators counter that those studies are conducted under strict guidelines and represent the most comprehensive data available.
Perhaps the more interesting question isn’t whether regulators rely on industry studies—they generally do. The more important question is who decides when the available evidence is sufficient, and what threshold of new independent evidence should trigger a formal reassessment. Those are governance questions as much as scientific ones, and they sit at the heart of the continuing debate over glyphosate.
Over 180,000 Roundup Lawsuits Later: What the Courts Found That Regulators Didn’t
While regulators debated methodology, tens of thousands of people who had used Roundup and developed non-Hodgkin lymphoma were taking their cases to court.
Juries repeatedly sided with them.
Between 2023 and 2025, juries returned verdicts totalling nearly US$5 billion before reductions and appeals. A Missouri appellate court upheld a $611 million award. A California court affirmed a $28 million verdict. In Georgia, a jury ordered Monsanto to pay $2 billion in punitive damages — later reduced — to a man who said he was never warned the product could harm him.
Bayer, which acquired Monsanto in 2018 and inherited every lawsuit with it, has reportedly set aside USD $16 billion to address remaining litigation. In February 2026, it proposed a $7.25 billion class settlement to resolve current and future non-Hodgkin lymphoma claims. A judge granted preliminary approval in March.
Then, on 25 June 2026 the US Supreme Court ruled 7-2 that state-level failure-to-warn claims against Roundup are preempted by federal law. Because the EPA has approved Roundup’s label without a cancer warning, Bayer generally cannot be sued under state failure-to-warn laws where those claims conflict with EPA-approved labelling.
The ruling was a sweeping win for Bayer. But more than that, it was a declaration about the EPA’s authority: when the federal agency approves a label, that approval supersedes what a state jury might think people deserve to be told.
New Zealand and Glyphosate: An Approval That Predates the Law Meant to Regulate It
New Zealand’s regulatory story on glyphosate runs parallel to the American one — and arrives at a similar dead end.
Glyphosate was approved for use here before the Hazardous Substances and New Organisms (HSNO) Act even came into force in 1996. A number of glyphosate-containing products were shifted into the HSNO framework during a transfer process in 2004. There has been no comprehensive reassessment of glyphosate under today’s HSNO reassessment process.
In 2024, the Environmental Law Initiative (ELI) applied to the New Zealand EPA for a reassessment, arguing that significant new information had emerged about glyphosate’s health and environmental effects. The EPA declined — finding grounds for reassessment had not been established.
ELI challenged that decision in the Wellington High Court. In October 2025, the High Court ruled against them, finding no reviewable error. ELI filed an appeal in November 2025, then withdrew it in May 2026.
The result: glyphosate remains approved in New Zealand, under an assessment framework that hasn’t been comprehensively revisited since the product entered the market here half a century ago.
New Zealand’s EPA does not independently test chemicals. The primary toxicological assessment focuses on the active ingredient — glyphosate — based largely on data provided by manufacturers and reviews by international regulators. It does not assess the full commercial formulations that people actually spray.
This matters because the thing people buy at the garden centre is not just glyphosate. It’s a mixture — with surfactants, solvents, and co-formulants — whose combined long-term effects have not been evaluated to the same extent as the active ingredient.
Who Bears the Burden of Proof When a Pesticide Is Already on the Shelf?
Here is the question regulators think they’ve answered: is glyphosate safe?
But notice whose job it is to ask. Under the current framework, the burden sits with the public — with communities, with organisations like ELI, with individual plaintiffs — to prove that a chemical already on the market causes harm. The manufacturer doesn’t have to prove it’s safe. It already has approval. The onus is on everyone else to dislodge it.
That’s not an accident. It’s a design choice. And it’s worth naming.
The honest answer to the safety question, given that design, is this: glyphosate is considered safe enough by most regulators at the exposure levels they regard as typical. That conclusion, however, rests on an evidence base that includes a substantial amount of data generated by the manufacturers themselves.
It also sits alongside an ongoing scientific dispute, a decade of high-profile litigation, and the experiences of thousands of people who say they developed non-Hodgkin lymphoma after using Roundup without ever being warned that one of the world’s leading cancer research agencies considered glyphosate a probable human carcinogen.
What regulatory systems are not designed to resolve — and perhaps cannot resolve — is the harder question underneath:
How Much Uncertainty Is Acceptable Before a Warning Is Required — and Who Decides?
The EPA asks whether risk is unreasonable. Juries, when given the chance, have been asking something closer to: should someone have told us this was possible?
The US Supreme Court has now answered that question, at least for future American plaintiffs: when the EPA speaks on a product label, the states must listen.
New Zealand’s EPA declined to speak at all — and the courts here agreed that was within its rights.
In both countries, the chemical stays on the shelf. The argument about what that means is far from over.
Glyphosate has been in registration review in the US since 2009. The EPA’s long-awaited final registration review decision — the completed version of a process that wound through two court challenges, a voluntary remand, a missed court deadline, and a full withdrawal — is expected later in 2026.
In New Zealand, glyphosate-containing products are regulated under the HSNO Act. The EPA’s July 2024 decision declining reassessment was upheld by the High Court in October 2025. ELI’s subsequent appeal was withdrawn in May 2026.
Further Reading
The story of glyphosate in New Zealand — who sprays it, who regulates it, who profits from it, and who bears the risk — runs deeper than any single article can cover. The resources below bring together our own investigations alongside the scientific and legal record. Take what’s useful. Share what matters.
Roundup vs Glyphosate: Why the Label Tells Only Half the Story
No More Glyphosate NZ
When regulators assess glyphosate, they assess the active ingredient — not the full commercial product people actually spray. This piece explains why the co-formulants in products like Roundup may pose risks that the official safety record completely ignores.
When the High Court Sided with the EPA: A Win for Procedure, Not Science
No More Glyphosate NZ
In October 2025, the High Court upheld the EPA’s refusal to reassess glyphosate. This piece unpacks what that ruling actually means — and what it reveals about the limits of judicial review as a tool for public health accountability.
NZ Glyphosate Submissions: What Really Changed — and What Didn’t
No More Glyphosate NZ
Over 3,100 New Zealanders submitted against proposed increases to glyphosate residue limits in food. Here’s what the government actually changed, what it didn’t, and what the fine print reveals about who the system is designed to protect.
Glyphosate and the EPA: The Judicial Review Explained
No More Glyphosate NZ
Before the High Court ruled, the Environmental Law Initiative took the EPA to court. This explainer covers what the case was actually about — not whether glyphosate causes cancer, but whether our regulator followed proper process when it chose not to find out.
IARC Monograph Volume 112: Glyphosate Classification
International Agency for Research on Cancer (WHO)
The original 2015 classification that triggered a decade of litigation, regulatory dispute, and public debate. The WHO’s cancer research arm concluded glyphosate is “probably carcinogenic to humans” — the finding regulators have spent ten years arguing against.
Challenging the EPA’s Regulatory Failure on Glyphosate
Environmental Law Initiative (ELI)
The Environmental Law Initiative’s own case summary — covering the legal challenge to the EPA’s decision not to reassess glyphosate, the High Court outcome, and what it means that glyphosate has never undergone a full risk assessment in Aotearoa.
Glyphosate Health Risks: Who’s Responsible?
No More Glyphosate NZ
When no single agency owns the problem — the EPA regulates substances, MPI sets residue limits, the Ministry of Health monitors public health, WorkSafe oversees worker exposure — the gaps between them become a place where accountability disappears.
The Monsanto Papers: Glyphosate on Trial
Carey Gillam / US Right to Know
The investigative book and reporting project that drew on internal Monsanto documents — obtained through litigation discovery — to reveal how the company worked to shape the science, ghostwrite studies, and influence regulators over decades. Essential background for understanding why courtroom evidence looks so different from the regulatory record.
The question this article asks — who carries the burden of proof when a chemical is already on the shelf? — doesn’t have a comfortable answer. But the more New Zealanders understand how the system works, the harder it becomes to accept that “within the legal limit” is the same as “safe.” If any of these resources prompt questions, we want to hear them.
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