Wait — the key “glyphosate is safe” paper wasn’t written by the authors?
For 25 years, one paper shaped global opinion about glyphosate’s safety.
Regulators cited it. Policymakers leaned on it. Industry waved it like a permission slip.
And here in New Zealand, the same paper helped justify why glyphosate-based weedkillers such as Roundup® were treated as “low risk” and allowed to saturate our food, soil, and waterways with almost no independent oversight.
But now something extraordinary has happened:
That cornerstone paper has finally been retracted.
And not because of new science.
Because of ghostwriting.
The Cornerstone Glyphosate “Safety” Study Has Been Retracted
That’s right.
The now-retracted paper — Williams, Kroes & Munro (2000) — concluded confidently that “under present and expected conditions of use, Roundup herbicide does not pose a health risk to humans”.
The retraction notice says: “The paper had a significant impact on regulatory decision-making regarding glyphosate and Roundup for decades.”
However, US Roundup/cancer litigation in 2017 revealed it to have been ghostwritten by Monsanto.
Yet in spite of that revelation, it continued over two decades to be cited as evidence supporting glyphosate’s safety. This fact was subjected to strong criticism in a peer-reviewed paper.
Let that land for a moment.
A ghostwritten paper — presented as independent science — shaped global policy for 25 years.
Why Was This Paper So Influential?
The paper, by Williams, Kroes, and Munro, was published in 2000 and concludes, “under present and expected conditions of use, Roundup herbicide does not pose a health risk to humans”.
For decades, it was treated as the foundational safety review behind regulator decisions.
Was It Really Ghostwritten by Monsanto?
But during US Roundup cancer lawsuits in 2017, court documents revealed something shocking:
Monsanto ghostwrote the paper.
Not “industry contributed.”
Not “industry provided data.”
Ghostwrote.
Regulators Kept Using It Anyway
Even after the ghostwriting became public, the Williams/Kroes/Munro paper continued to be cited by agencies, consultants, and industry groups defending glyphosate’s safety.
In fact, a later peer-reviewed critique warned that relying on such tainted evidence undermines public trust and distorts chemical regulation.
Yet nothing happened.
Not until now.
What This Means for New Zealand
This retraction:
- Undermines the scientific foundation regulators used to claim glyphosate is “non-carcinogenic”
- Calls into question historical approvals and reassessments
- Strengthens the case for a full, independent, transparent review of glyphosate-based weedkillers
- Highlights the risk of relying on industry-funded data over independent evidence
And frankly, it raises the obvious question:
If the cornerstone paper is now gone, what exactly is left holding up the claim that glyphosate is safe?
A Major Shift in the Glyphosate Evidence Base
And meanwhile, our own testing at NoMoreGlyphosate.nz has found glyphosate or AMPA in common household foods — including honey, Weet-Bix, and cereals.
How can New Zealand continue to rely on regulatory decisions built on a foundation we now know was compromised?
Where This Leaves Us
This isn’t a footnote.
This isn’t an academic technicality.
This is a pillar collapsing.
A key paper is gone.
A quarter-century of regulatory reassurance suddenly looks fragile.
And the burden shifts — finally — back onto regulators to prove glyphosate’s safety with real, independent, transparent evidence.
Because one thing is clear:
If a ghostwritten paper can shape regulation for 25 years, then something in the system is deeply broken.
New Zealand has a chance to do better.
The question now is: will we?
Resources & References
Before we move on, it’s worth taking a moment to look at the evidence that sits beneath this story — the retraction, the litigation documents, the independent science, and the regulatory material that shaped New Zealand’s stance for more than two decades. None of this exists in isolation. When you read these papers side by side, a clearer pattern emerges: the foundations of glyphosate’s “safety” narrative were never as solid as we were told.
This is the reading that helps you see the gaps regulators won’t acknowledge — and the questions the public was never encouraged to ask.
Williams, G.M., Kroes, R., & Munro, I.C. (2000).
Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans. Regulatory Toxicology and Pharmacology, 31(2), 117–165.
Retracted by publisher.
https://doi.org/10.1006/rtph.1999.1371
Elsevier Retraction Notice (Late November 2025).
Retraction of Williams, Kroes & Munro (2000) due to undisclosed contributions and conflicts of interest.
https://www.sciencedirect.com/science/article/pii/S0273230099913715/pdfft?md5=0bc829809ce23357275f9fcf4d69006c&pid=1-s2.0-S0273230099913715-main.pdf
Gillam, C. (2017).
Monsanto Papers reveal ghostwriting and manipulation of scientific literature. U.S. Roundup litigation document disclosures.
(Primary source documents accessible via U.S. Right to Know.)
https://usrtk.org/monsanto-papers/
Fagan, J. et al. (2019).
Organic agriculture is the future of farming. (Includes analysis of scientific ghostwriting practices in pesticide approvals.) Environmental Sciences Europe.
https://enveurope.springeropen.com/
Benbrook, C.M. (2019).
How did the US EPA and IARC reach diametrically opposed conclusions on glyphosate’s genotoxicity?
Environmental Sciences Europe, 31(2).
https://enveurope.springeropen.com/articles/10.1186/s12302-018-0184-7
Further Reading
If you’re exploring how weak science and regulatory gaps shape real-world exposure, these articles provide useful context:
The Monsanto Papers & the Glyphosate Legal Battle — an overview of the court-released internal documents showing how industry influence shaped so-called “independent” glyphosate research.
https://nomoreglyphosate.nz/the-monsanto-papers-glyphosate-legal-battle/
Does Glyphosate Cause Cancer?
A deep dive into cancer classifications, global evidence, and why regulators keep disagreeing.
https://nomoreglyphosate.nz/does-glyphosate-cause-cancer/
Glyphosate and Hormone Disruption: What We Know So Far
How glyphosate-based weedkillers interact with endocrine pathways — and why regulators have overlooked it.
https://nomoreglyphosate.nz/glyphosate-hormone-disruption/
Why Raising MRLs Threatens Public Health
How increasing allowable residues reshapes risk — especially when foundational science collapses.
https://nomoreglyphosate.nz/raising-mrls-public-health-risk/
Why Glyphosate Isn’t Just a Weed Killer — It’s a Public Health Issue
A broader look at glyphosate’s overlooked pathways and chronic exposure risks.
https://nomoreglyphosate.nz/why-glyphosate-isnt-just-a-weed-killer/
Glyphosate in NZ Honey: Our First Test Results
Independent testing showing real-world residues in common foods.
https://nomoreglyphosate.nz/glyphosate-in-nz-honey-first-test-results/
Weet-Bix Glyphosate Test Results
What we found in one of New Zealand’s most iconic breakfast foods.
https://nomoreglyphosate.nz/weet-bix-glyphosate-test-results/
Glyphosate in Waterways: A Contamination Crisis
What happens when glyphosate leaves the paddock and enters our streams, rivers, and drinking water sources.
https://nomoreglyphosate.nz/glyphosate-waterways-contamination/
As always, you don’t need to accept any single source as truth. The power comes from seeing how these pieces fit together — how the ghostwriting revelations, the retraction, the litigation evidence, and the independent studies form a picture far bigger than one flawed paper. When a chemical becomes this widespread, the science behind its approval should be beyond reproach. Instead, the deeper you look, the more uncertainty you find.
And that raises the real question: if this is what slipped through in plain sight, what else have we missed?
Image Source & Attribution
The feature image on this page is a screenshot of the Williams, G.M., Kroes, R., & Munro, I.C. (2000). Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans. PDF, edited using Canva.com
