This month s meeting in Lyon, France, of the International Agency for Research on Cancer (IARC) the branch of the UN s World Health Organization that studies the relationship between environmental and lifestyle risk factors and cancer focused on pesticides. The committee concluded that of the five pesticides evaluated, three were probably carcinogenic, a 2A classification, despite the fact that neither the U.S. EPA nor the European Chemical Agency had classified these pesticides as such. A classification of 2A is one step removed from a Group 1 classification - Carcinogenic to humans. One of the newly-tarred pesticides was glyphosate, an herbicide. Glyphosate is a component of Roundup, Monsanto s widely used weedkiller, which has been in common household (as well as agricultural) use for decades.
The problems with this conclusion are manifold: first, the studies used by IARC are not new and in fact, these same studies have been reviewed in much more detail by regulatory agencies such as the U.S. EPA, the German Risk Agency (among others) who have concluded that glyphosate is not a carcinogen. The German Risk Agency recently concluded in a reevaluation in January 2015 that the available data do not show carcinogenic or mutagenic properties of glyphosate nor that glyphosate is toxic to fertility, reproduction or embryonal/fetal development in laboratory animals, and in epidemiological studies in humans, there was no evidence of carcinogenicity and there were no effects on fertility, reproduction and development of neurotoxicity that might be attributed to glyphosate.
As former ACSH Trustee and FDA official Dr. Henry Miller explains in his piece in Forbes, IARC based their decision to classify glyphosate as a probable human carcinogen based on its potential hazard, rather than actual risk of harm. According to the data, glyphosate may cause harm at extremely high doses. However, as Dr. Miller says, the dose makes the poison, and the reality is that glyphosate is not a human health risk even at levels of exposure that are more than 100 times higher than the human exposures that occur under conditions consistent with the product s labeling.
Even the new data, which the German Risk Agency had not evaluated at the time of its reevaluation because it had not yet been published, failed to find a link between glyphosate and cancer. The conclusion from an article in the March 2015 issue of Critical Reviews in Toxicology: The lack of a plausible mechanism, along with published epidemiology studies, which fail to demonstrate clear, statistically significant, unbiased and non-confounded associations between glyphosate and cancer of any single etiology, and a compelling weight of evidence, support the conclusion that glyphosate does not present concern with respect to carcinogenic potential in humans.
Although regulatory agencies continue to affirm the safety of these pesticides, IARC will continue to make conclusions without relying on the science. As Dr. Miller sadly predicts, re: the upcoming June ruling by IARC on three additional pesticides, My bet is that none of them will get through unscathed. That s much more of a sure thing than my predictions about March Madness.
We here at ACSH have been keen observers of the working of IARC over the years, and while this ruling is disappointing for anyone devoted to sound science as the basis of regulatory policy, no one should be surprised. This agency of the WHO/UN is among the worst of the hyper-regulators, and has developed a well-deserved reputation for breezing past or simply ignoring the latest (or even the consensus) science in the service of their precautionary principle-based agenda.
Anyone who wishes more information on the uses and safety profile of glyphosate (among many other pesticides) should review our publication on the subject, here.