2000 Monsanto-backed Roundup Safety Study Retracted Over Ethical Concerns
The journal Regulatory Toxicology and Pharmacology has formally retracted a 2000 paper that claimed no health risks from glyphosate, the active ingredient in Monsanto's Roundup weedkiller. The retraction cites serious ethical concerns regarding authorship, independence, and the integrity of the carcinogenicity studies underpinning the paper.
The original study was authored by Gary Williams, Robert Kroes, and Ian Munro, external scientists unaffiliated with Monsanto. Despite this, Monsanto heavily relied on the paper as a key defense against claims linking Roundup to cancer. Internal Monsanto documents released amid litigation reveal a company strategy to influence the paper's publication via a program called "Freedom to Operate," with emails praising involved staff and planning to use the paper to defend Roundup and distinguish it from generic products.
An email from Lisa Drake dated 2000 detailed Monsanto personnel involvement and described the publication as the definitive reference on Roundup safety. Another email discussed distributing Roundup-branded polo shirts to eight individuals who worked on the papers. Further documents show Monsanto scientist William Heydens in 2015 suggested ghostwriting and paying external scientists to edit and sign the study, indicating the Williams, Kroes, and Munro paper was ghostwritten.
The retraction notice emphasizes misrepresentation of author contributions, sponsor influence, and conflicts of interest. It highlights that the carcinogenicity conclusions relied primarily on unpublished Monsanto studies while disregarding other published research.
Bayer, which acquired Monsanto in 2018, acknowledged Monsanto's involvement in the study but stated that a broad majority of glyphosate research continues to affirm its safety. The EPA declared it has not based its assessments on the retracted article and will not rely on it in its upcoming 2026 glyphosate safety evaluation.
The retraction occurs amid ongoing Roundup litigation and potential Supreme Court review. This story is co-published with the New Lede, a journalism project of the Environmental Working Group.
