Glyphosate cancer claims remain contested despite renewed US policy support
A new US policy push for glyphosate production has intensified political attacks on the herbicide, but FactCheck.org says the scientific evidence remains mixed and regulators still do not treat carcinogenicity as settled.
A fresh political fight over glyphosate has opened in the United States after a February executive order from the Trump administration promoted production of glyphosate-based herbicides as a matter of national security. FactCheck.org says the political rhetoric has become much more absolute than the science itself. Some studies have found links between glyphosate exposure and cancer, especially non-Hodgkin lymphoma in agricultural workers, but those findings have not been consistent across the evidence base.
The article notes that glyphosate was first marketed by Monsanto in 1974 as Roundup, and that Bayer, which acquired Monsanto in 2018, is now the only US manufacturer of glyphosate, although imported generics are also sold. Trump’s February 18 executive order was widely seen as clashing with the MAHA movement, which generally opposes pesticides and has made glyphosate a major target.
Health and Human Services Secretary Robert F. Kennedy Jr. has previously said glyphosate causes cancer, even though he defended the executive order. Democratic politicians then made their own forceful claims. Sen. Cory Booker said the order was a blow to Americans who had developed cancer from glyphosate, while Sen. Ed Markey said Trump was siding with a chemical company that causes cancers. FactCheck.org argues those statements go further than the underlying evidence can support.
The article points to a large National Institutes of Health study of agricultural workers, published in 2017, that did not find an association between glyphosate and non-Hodgkin lymphoma or other cancers. That lack of a consistent signal is one reason why regulatory agencies, including the US Environmental Protection Agency, have concluded glyphosate is unlikely to pose a carcinogenic risk under real-world conditions. At the same time, the International Agency for Research on Cancer classified glyphosate in 2015 as “probably carcinogenic to humans,” based on animal evidence and limited human evidence.
FactCheck.org quotes professor emeritus David Eastmond as saying the overall picture on glyphosate is “messy,” with human studies, animal studies and mechanistic evidence all open to competing interpretations. The practical takeaway for agriculture is that glyphosate remains both commercially central and politically vulnerable. It is one of the world’s most widely used herbicides, yet it continues to sit in a zone of unresolved scientific and regulatory dispute rather than clear consensus.