25 Years Later: Landmark 2000 Roundup Safety Review Retracted Over Monsanto Ghostwriting

A influential 2000 review that concluded the herbicide glyphosate (commercially known as Roundup) "does not pose a health risk to humans" has been formally retracted 25 years after publication amid evidence of industry influence and ethical breaches.

Why the Paper Was Retracted

In a retraction notice published in November 2025, the journal Regulatory Toxicology and Pharmacology said the article was withdrawn because of "several critical issues" that undermined its academic integrity. Co-editor-in-chief Martin van den Berg noted that attempts to contact Gary Williams, the paper's sole surviving listed author, produced no response.

"The lack of clarity regarding which parts of the article were authored by Monsanto employees creates uncertainty about the integrity of the conclusions drawn." — Martin van den Berg, Regulatory Toxicology and Pharmacology

Key Problems Identified

The journal highlighted three central concerns:

• Assessments of cancer and genetic-toxicity risks relied heavily on unpublished Monsanto studies.
• Numerous long-term studies that were available at the time were omitted from the review.
• There was insufficient disclosure of company involvement and potential financial ties, raising questions about authorial independence.

Background And Impact

The review, authored in 2000 by Gary Williams, Robert Kroes, and Ian Munro, became one of the most-cited papers in the glyphosate literature. Harvard scientist Naomi Oreskes found it has been cited in more than 800 academic papers, dozens of government documents, and multiple Wikipedia entries — material that has influenced scientific debate, regulation, and public perception.

Legal revelations in a 2017 court case first exposed that Monsanto employees had helped ghostwrite parts of the safety assessment. Monsanto introduced Roundup in 1974; the company was acquired by Bayer in 2018, and Bayer continues to assert that glyphosate is safe when used as directed.

Scientific Dispute And Legal Fallout

In 2015, the World Health Organization's International Agency for Research on Cancer (IARC) classified glyphosate as a "probable carcinogen," based mainly on animal studies. Other regulatory bodies have reached different conclusions, leaving the scientific community divided and emphasizing the need for rigorous, independent research.

By 2020 Bayer had paid roughly $10 billion to settle Roundup-related litigation, and tens of thousands of cases have been filed alleging links between glyphosate exposure and cancer. A Science review of the retracted paper documented its wide influence on research, policy, and public discussion.

What Comes Next

The retraction removes a high-profile piece of evidence that had been used to argue glyphosate's safety and underscores how industry involvement can distort scientific literature. Editors, regulators, and independent researchers now face the challenge of reassessing the evidence base to determine glyphosate's true risks and to restore public trust in the process.