By Lynn L. Bergeson, James V. Aidala, and Lisa R. Burchi
On March 20, 2015, the United Nations World Health Organization’s International Agency for Research on Cancer (IARC) announced it had completed evaluations assessing the carcinogenicity of five organophosphate pesticides. Specifically, IARC classified the herbicide glyphosate and the insecticides malathion and diazinon as probably carcinogenic to humans (Group 2A), and classified the insecticides tetrachlorvinphos and parathion as possibly carcinogenic to humans (Group 2B). IARC also found there is “limited evidence” that glyphosate can cause non-Hodgkin’s lymphoma and lung cancer in humans.
A summary of the final evaluations, together with a brief rationale, is published online in The Lancet Oncology; the detailed assessments will be published as Volume 112 of the IARC Monographs. IARC’s press release announcing its evaluation is available at http://www.iarc.fr/en/media-centre/iarcnews/pdf/MonographVolume112.pdf.
Monsanto, on behalf of glyphosate task forces in the U.S. and the European Union (EU), immediately voiced its vigorous disagreement with IARC’s conclusions, noting various scientific issues with IARC’s evaluation that resulted in a conclusion that has not been reached following review by the U.S. Environmental Protection Agency (EPA) and in the EU. Monsanto’s statement is available at http://news.monsanto.com/news/monsanto-disagrees-iarc-classification-glyphosate.
The IARC announcement with regard to glyphosate will further energize both sides of the debate about genetically modified organism (GMO) crops, since there are several crops that have been genetically engineered to be resistant to glyphosate. If some occupational risks are identified as needing possible further mitigation, the distinction between food safety issues and occupational risks may be lost in the rhetoric. Opponents of GMO crops and those who support GMO food product labels can be expected to cite the IARC designation regardless of any further clarification or nuance that the scientific debate over the data might provide. Defenders of the technology will insist that not only is the IARC designation wrong and misleading, but it is clearly at odds with numerous other conclusions reached by multiple competent governmental authorities concerning the safety of using glyphosate and especially consuming GMO crops.
Regardless of Monsanto’s rapid and detailed response, “dueling science” views are not helpful towards enhancing public confidence in the safety of the food supply, which is ultimately where this headline will be most influential. That will only add pressure on the review process and conclusions contained in the expected EPA registration review of glyphosate data scheduled for completion in 2015.