WASHINGTON, Sept. 16, 2016 – Data reviewed by the Environmental Protection Agency on the safety of glyphosate fail to prove or even suggest the herbicide causes cancer in humans, according to an agency paper posted online in advance of a meeting of EPA scientific advisers next month.

“The available data at this time do no support a carcinogenic process for glyphosate,” the report said.

In addition, “Based on all of the available data, the weight-of-evidence clearly do not support the descriptors ‘carcinogenic to humans’ and ‘likely to be carcinogenic to humans’ at this time,” according to EPA’s paper, “Glyphosate Issue Paper: Evaluation of Carcinogenic Potential.” The paper is one of more than 80 documents posted for review in preparation for a Scientific Advisory Panel (SAP) meeting next month on glyphosate’s potential carcinogenicity.

EPA also said that there were not enough data to say there is “suggestive evidence of carcinogenic potential.” 

“Considering the entire range of information for the weight-of-evidence, the evidence outlined above to potentially support the ‘suggestive evidence of carcinogenic potential’ descriptor are contradicted by other studies of equal or higher quality and, therefore, the data do not support this cancer classification descriptor,” EPA’s paper said.

Monsanto issued a brief statement shortly after the paper was posted Friday, calling the agency’s conclusion “consistent with EPA’s internal Cancer Assessment Review Committee, the Joint FAO/WHO Meeting on Pesticide Residues, and regulators in Canada, Europe, Japan, New Zealand and around the world.

“There is no credible evidence that glyphosate is a carcinogen,” the company said. “Given the overwhelming opinion of scientists and regulators around the world, we feel an SAP for glyphosate is an unnecessary use of resources. Nonetheless, we are fully confident that if the SAP follows sound scientific principles and reviews the overwhelming weight of evidence, it will reaffirm that glyphosate is not a carcinogen.”

The Natural Resources Defense Council had a different take. NRDC senior scientist Jennifer Sass said that EPA's conclusions are not supported by the science.

"After decades of using glyphosate on food crops, and a 2014 GAO report that was highly critical of the FDA and USDA pesticide residue monitoring programs and specifically noting the need to test glyphosate, we are glad that the federal government is finally testing for residues in food," Sass said in an email. "But, EPA isn’t waiting for the data. So, how can EPA make a risk finding 'at doses relevant for human health risk assessment' when we don’t know what doses people are being exposed to?"

The agency said it could not reach a conclusion on whether glyphosate causes non-Hodgkin lymphoma.

“In epidemiological studies, there was no evidence of an association between glyphosate exposure and numerous cancer outcomes,” EPA said. “However, due to conflicting results and various limitations identified in studies investigating (non-Hodgkin lymphoma), a conclusion regarding the association between glyphosate exposure and risk of NHL cannot be determined based on the available data.”

In a report released in March 2015 that concluded glyphosate was a probable human carcinogen, the World Health Organization’s International Agency for Research on Cancer (IARC) found “limited evidence of carcinogenicity in humans for non-Hodgkin lymphoma. The evidence in humans is from studies of exposures, mostly agricultural, in the USA, Canada, and Sweden published since 2001.”

EPA’s report also said that “genotoxicity studies demonstrate that glyphosate is not directly mutagenic or genotoxic in vivo.” (In vivo refers to tests performed on live animals). “The available data regarding non-cancer endpoints also do not provide any support for a carcinogenic process for glyphosate, and have shown glyphosate has relatively low toxicity.”

The agency said more research and analysis is needed to understand how glyphosate affects human health, calling for “additional epidemiology studies and updates” from the National Institutes of Health Agricultural Health Study.

“This evaluation focused on studies on the active ingredient glyphosate; however, additional research could also be performed to determine whether formulation components, such as surfactants, influence the toxicity of glyphosate formulations,” EPA said. “The agency has been working on plans to initiate research given these identified data gaps.”

The most widely used herbicide in the world, glyphosate is the active ingredient in Monsanto’s Roundup. After IARC’s assessment was released, other food safety bodies examined glyphosate and came to other conclusions.

“In November 2015, the European Food Safety Authority (EFSA) determined that glyphosate was unlikely to pose a carcinogenic hazard to humans,” EPA’s paper said. 

“In May 2016, the Joint Food and Agriculture Organization (FAO)/WHO Meeting on Pesticide Residues (JMPR), another subdivision of the WHO, concluded that glyphosate was unlikely to pose a carcinogenic risk to humans from exposure through the diet. Some individual countries (e.g., France, Sweden) have been moving to ban glyphosate based on the IARC decision, while other countries (e.g., Japan, Canada) have continued to support their conclusion that glyphosate is unlikely to pose a carcinogenic risk to humans.”

EPA was not impressed by some of the studies IARC used, saying it had given them “a low quality ranking.”