The US state of California has officially placed the chemical glyphosate – the main ingredient in Monsanto’s best-selling herbicide Roundup – on its Prop 65 list of substances “known by the state to cause cancer”.
California has been planning to formally place glyphosate under its Prop 65 regulation since 2015, when the World Health Organization’s International Agency for Research on Cancer (IARC) reclassified glyphosate as a “probable carcinogen.”
But the US state had been thwarted by a legal action brought by Monsanto, which argues that “listing glyphosate under Prop 65 is unwarranted on the basis of science and law”.
Enforcement of Prop 65 triggers a requirement for a compulsory cancer warning label to be included on all products containing a designated ingredient. This requirement has been delayed while Monsanto pursues its case against California.
The WHO/IARC’s decision to classify glyphosate as “probable carcinogen” was strongly welcomed by many health campaigners and by the organic farming community. But in 2016, a co-analysis by the UN’s Food and Agriculture Organisation (FAO) and World Health Organisation found that the chemical was “unlikely to pose a carcinogenic risk to humans from exposure through the diet”. Some scientists have argued that the IARC had based its 2015 decision on outright hazard as opposed to actual risk. Henry Miller, a molecular journalist and fellow at Stanford University’s Hoover Institution, claimed in a recent LA Times article that “IARC looks for any shred of evidence to prove that something might cause cancer, even under extreme circumstances”.
Separate to the California case, Monanto is defending itself in a lawsuit filed in federal court in Wisconsin on June 20 by residents of Wisconsin, Illinois, California, New York, New Jersey, and Florida. That case alleges that Monsanto and Roundup distributor Scotts Miracle-Gro falsely claim that glyphosate “targets an enzyme that is not found in people or pets.” The plaintiffs argue that glyphosate affects an enzyme found in “beneficial gut bacteria” critical to health.