When credible evidence of serious harm exists, the precautionary principle says act first and seek certainty later. So why has the opposite happened with glyphosate?
Let’s start with a thought experiment.
You are a decision-maker. A regulator. A council manager. A procurement officer. A retailer. A parent.
Someone walks into your office and says: seventeen independent scientists from eleven countries have reviewed the available evidence and concluded that this substance probably causes cancer.
What do you do?
If you answered “keep selling it,” “keep spraying it in public parks,” or “keep stacking it next to the breakfast cereal” — congratulations. You are in good company with the New Zealand EPA, most of our regional councils, Mitre10, Bunnings, every garden center, and supermarket chain in the country.
The Precautionary Principle Isn’t a Suggestion
The precautionary principle has become a widely recognised principle of environmental and public health decision-making. It says: when credible evidence of serious harm exists, act to prevent that harm — don’t wait for proof beyond all doubt.
It is why governments eventually removed asbestos once the evidence became overwhelming. Why we removed lead from petrol before every scientific question had been resolved. Why we put warning labels on cigarettes while sections of the tobacco industry continued to dispute the evidence.
The precautionary principle exists precisely for situations where the evidence is strong but not yet unanimous — where waiting for certainty means waiting until people are already sick.
The International Agency for Research on Cancer (IARC) is not a fringe body. It is the cancer research arm of the World Health Organisation. In 2015, after a year-long systematic review of all publicly available evidence, it classified glyphosate as “probably carcinogenic to humans” — Group 2A, the same category as red meat, shift work, and emissions from high-temperature frying.
“Probably” in IARC’s language is not a shrug. It is a formal scientific determination meaning the evidence is sufficient to warrant concern and action.
So here is the question nobody in a position of authority seems willing to answer directly:
How do you apply the precautionary principle to a substance classified as probably carcinogenic — and conclude that no precaution is necessary?
What “Not Likely Carcinogenic” Actually Means — and What the EPA Isn’t Telling You
The standard regulatory response to IARC’s finding has been to cite the counter-conclusion: that the US EPA, the EU Food Safety Authority, and New Zealand’s own EPA have all found glyphosate “not likely to be carcinogenic to humans.”
Let’s sit with that phrase for a moment.
Not likely.
Not “does not.” Not “cannot.” Not “we have established beyond reasonable doubt that this substance is safe.”
Not likely.
That is the foundation on which glyphosate remains in supermarkets, school grounds, public parks, and waterways across New Zealand. A probabilistic assessment of non-harm — based on a body of evidence that includes studies submitted by manufacturers as part of the pesticide registration process — is treated as a definitive clean bill of health, despite those manufacturers having a direct financial interest in the product remaining on the market.
Meanwhile, the US EPA’s own “not likely” determination was vacated by a federal court in 2022, which found parts of the agency’s cancer analysis legally inadequate and sent the issue back for further consideration. The court did not conclude that glyphosate causes cancer. It concluded that the EPA had not adequately supported its finding. The agency then withdrew the cancer portion of its assessment.
And yet — because regulatory systems are designed to keep products legal unless actively removed — glyphosate stayed on shelves through the entire legal uncertainty.
“Not likely to be carcinogenic” and “probably carcinogenic to humans” cannot both be the final word. They reflect fundamentally different ways of interpreting the evidence. And the people bearing the risk of that uncertainty are not the regulators.
Councils, Contractors, Retailers: Who Is Accountable When Glyphosate Causes Harm?
Here is where the accountability question becomes concrete — and uncomfortable.
When a council contractor sprays glyphosate on a school playground, a park border, or a roadside berm, they are doing so on the instruction of a procurement decision made somewhere up the chain. That decision was made by someone who read “approved by the EPA” and went no further.
When a home gardener reaches for Roundup at the supermarket, they are trusting that the label tells them everything they need to know. It doesn’t. The label tells them the product kills weeds. It doesn’t tell them that the WHO’s cancer agency thinks it probably causes cancer. It doesn’t tell them that the surfactants and co-formulants mixed in with the glyphosate may be more toxic than the active ingredient itself. It doesn’t tell them that in New Zealand, the formulated product they are holding has never undergone a comprehensive carcinogenicity assessment as a complete commercial formulation — only the isolated active ingredient.
And when they get sick — if they get sick — who is accountable?
The regulator will point to the approval. The manufacturer will point to the label. The council will point to the contractor. The contractor will point to the product registration. The retailer will point to the regulator. And round it goes.
This is not a conspiracy. It is something more mundane and more damaging: a system deliberately structured so that no single person or institution carries the consequence of the decision. Risk is distributed to those at the end of the chain — the workers, the residents, the children playing on the grass — while accountability evaporates somewhere in the middle.
Over 100,000 Roundup Lawsuits and $18 Billion Later — and New Zealand Still Has No Cancer Warning
Where there is smoke, we are told, there is fire.
So what do we make of this?
Over 100,000 lawsuits filed in the United States by people who developed non-Hodgkin lymphoma after using glyphosate-based products. Juries — ordinary people, hearing evidence under oath, with internal corporate documents disclosed — repeatedly finding in favour of the plaintiffs. Bayer setting aside USD $16 billion to manage the fallout. A $7.25 billion class settlement proposed in 2026.
The Missouri Supreme Court upholding a $611 million verdict. A Georgia jury awarding $2 billion in punitive damages to a man never warned the product could harm him.
These are not activist findings. These are legal findings reached after courts heard expert evidence, internal corporate documents, and testimony under oath.
And in New Zealand? Roundup is still sold without a health warning. Councils still spray it in public spaces with minimal notification. The EPA declined to reassess it in 2024. The High Court upheld that decision in 2025.
There is smoke everywhere. And our institutions have collectively decided that looking directly at it is not their job.
Why Nobody Is Personally Liable When a Glyphosate Decision Turns Out to Be Wrong
Here is the most important structural fact in this entire debate, and the one least likely to appear in any official communication:
The people who decide glyphosate is safe do not bear the consequences if they are wrong.
A regulator who approves a chemical faces no personal liability if it later proves harmful. Their institution may face criticism — but even that is limited, because they can point to the international consensus, the data they were given, the process they followed.
A council manager who signs off on a spraying contract faces no legal exposure if a contractor later develops cancer. They followed approved practice.
A retailer who stocks a registered product carries no warning obligation beyond what the label — approved by the regulator — requires.
The precautionary principle was designed for exactly this situation. It was designed to ensure that the burden of proof sits with those proposing to introduce risk — not with those who will be exposed to it. It was designed to ensure that “we didn’t know for certain” is not an adequate defence after the fact.
But in practice, under the regulatory frameworks governing glyphosate in New Zealand and most of the world, the burden has been entirely reversed. The public must prove harm. The manufacturer must only maintain approval. And the regulator must only avoid making a “reviewable error” — a legal standard, not a health one.
That is not the precautionary principle. That is its opposite.
If Glyphosate Probably Causes Cancer, What Does the Precautionary Principle Require You to Do?
You don’t have to be an EPA official to make a decision about glyphosate. You might be a council CEO. A school principal. A property manager. A farmer. A parent deciding whether to spray the driveway while the kids are home.
So here is the question, plainly put:
The WHO’s cancer agency says this substance probably causes cancer. The regulatory approval is under ongoing legal challenge. The manufacturer has paid billions to settle lawsuits from people who got sick using this product. The full commercial formulation — the thing you actually spray — has never been comprehensively assessed in New Zealand.
In good conscience, can you honestly say the remaining uncertainty is too small to justify taking precaution?
And if the answer is anything less than an unequivocal yes — what does the precautionary principle require you to do?
Not the regulator. You.
Because that is what accountability actually looks like. Not a bureaucratic process that distributes responsibility until it disappears. Not a label that tells you only what the law requires. Not a minister who defers to an agency that defers to international standards that defer to industry data.
You. Holding the spray gun. Signing the contract. Stocking the shelf. Making the call.
The smoke is there.
The precautionary principle is formally recognised in New Zealand’s Resource Management Act and referenced in multiple environmental policy frameworks.
In the case of glyphosate, regulators have yet to invoke it.
Further Reading
The argument in this piece — that the precautionary principle has been designed out of the system, and that accountability has been distributed until it disappears — is not theoretical. The articles and investigations below document what that looks like in practice: in playgrounds, in council contracts, in workers with no medical follow-up, and in a health system that cannot even track what it refuses to test for.
Glyphosate in NZ Playgrounds: Why Should We Assume Safety?
No More Glyphosate NZ
Glyphosate is routinely sprayed in public playgrounds across New Zealand — with almost no residue testing to confirm what remains. This piece examines what international testing has found on playground surfaces and equipment, and asks why New Zealand councils aren’t asking the same questions.
Sprayed, Splashed, Soaked: Auckland Council’s Glyphosate Exposure Incidents Are a Wake-Up Call
No More Glyphosate NZ
Six documented glyphosate exposure incidents at Auckland Council in two years — leaking knapsacks, face splashes, soaked clothing. Zero toxicological follow-up. Zero ACC tracking. This is what the accountability gap looks like at ground level, and it raises an uncomfortable question: what happens when those workers get sick?
Why NZ’s Health System Can’t Track Glyphosate Exposure
No More Glyphosate NZ
Health New Zealand has confirmed it does not collect data on illnesses caused by glyphosate exposure — even in hospitals. There is no surveillance system, no inter-agency reporting, and no national database. If we’re not measuring it, we can’t see it coming. And if we can’t see it coming, nobody is accountable when it arrives.
Glyphosate Health Risks: Who’s Responsible?
No More Glyphosate NZ
MPI sets residue limits. WorkSafe handles occupational safety. The EPA approves the substance. The Ministry of Health monitors public health. And when asked who is responsible for tracking worker illness from glyphosate exposure, each agency points to the next. This piece maps the accountability black hole at the centre of New Zealand’s chemical regulation system.
Glyphosate Spray Drift: A Hidden Risk to Communities
No More Glyphosate NZ
Spray drift is not a theoretical concern — it is documented and measurable. Glyphosate is being deposited on school boundaries, residential properties, and waterways without the knowledge or consent of the people living nearby. If legal use can result in illegal exposure, the “used according to the label” defence begins to look very thin indeed.
Whangārei Glyphosate Review: When Safeguards Aren’t Written Into Contracts
No More Glyphosate NZ
Whangārei District Council commissioned a formal review of its glyphosate use after sustained public pressure. The result was a set of recommendations — many of which were not written into enforceable contracts. A council can have a policy. That policy can look good on paper. And none of it matters if it isn’t binding on the contractors holding the spray gun.
Glyphosate and Children: The Precautionary Case
No More Glyphosate NZ
When it comes to children’s health, the precautionary principle should be the starting point — not something that needs to be argued for after the fact. This piece examines why children are more vulnerable to pesticide exposure, why current residue limits don’t account for that, and what parents, schools, and communities can do right now.
The NMGNZ Council Herbicide Transparency Project
No More Glyphosate NZ
Councils across New Zealand are spraying glyphosate in public spaces — parks, roadsides, sports fields, playgrounds — often without meaningful public notification. Through Official Information Act requests, we’ve been documenting what each council uses, where, how often, and what oversight exists. The results reveal how wide the gap is between stated policy and actual practice.
The precautionary principle asks a simple question: if you’re not sure it’s safe, why are you proceeding as if it is? The articles above don’t just ask that question in the abstract. They show, in specific detail, where the failure to apply it is landing — on workers, on children, on communities who never consented to be part of the experiment.
Image Source & Attribution
We’re grateful to everyone who helps document the reality of glyphosate in New Zealand. The feature image on this page was supplied by No More Glyphosate NZ.
