Glyphosate has long been considered as an herbicide with no unacceptable health risk. In 2015, its classification as “probably carcinogenic” by the International Agency for Research on Cancer (IARC) changed the situation, and in 2017 the European Union renewed its authorisation for only five years with France even wanting to “get out of glyphosate” in three years’ time. However, other official risk assessment agencies have contradicted the IARC’s opinion and, as our study attempts to show, this discrepancy is not scientifically explainable. On the other hand, the IARC has a clear lack of ideological neutrality and some IARC experts have financial ties with lawyers exploiting the tort law in the United States based on the IARC’s opinion on glyphosate. In Europe, claims of a universal contamination of the population by this herbicide was propagated following urine analyses of volunteers. However, the unreliability of the tests used in these activist campaigns has been established. The glyphosate case confirms the necessity of trustworthy scientific authorities to separate “the wheat from the tares”. In addition, the influence of activist structures having a pretence to science and the questioning of official risk assessment agencies present a problem in terms of risk management by the political authorities and public perception. All the more so when journalists entered the debate, some involved in interpreting scientific evidence whilst others drew attention to the supposed influence of Monsanto on researchers or on scientific risk experts.

This study was written by Marcel Kuntz, Research Director at the French National Centre for Scientific Research (CNRS), Invited lecturer at Grenoble-Alpes University, 2017 gold medal recipient from the French Academy of Agriculture.