The Environmental Protection Agency has reaffirmed its conclusion that glyphosate, the active ingredient in Bayer’s Roundup, is "likely" not carcinogenic, in a proposed registration decision that would allow the herbicide to continue to be used in the United States.

“EPA did not identify any risks of concern for humans from exposure to glyphosate,” the agency said in its proposed interim decision. “In addition, the agency determined glyphosate is not likely to be carcinogenic to humans,” though it said it did identify risks “primarily from spray drift for non-target organisms.”

“EPA has found no risks to public health from the current registered uses of glyphosate,” EPA Administrator Andrew Wheeler said in a news release, and Agriculture Secretary Sonny Perdue said “USDA applauds EPA’s proposed registration decision as it is science-based and consistent with the findings of other regulatory authorities that glyphosate does not pose a carcinogenic hazard to humans.”

The cancer-causing potential of the herbicide has been a controversial, widely debated subject ever since the International Agency for Research on Cancer concluded in March 2015 that glyphosate was a probable human carcinogen. That conclusion, while not replicated by governmental regulatory bodies, has been used to buttress arguments by plaintiffs in California state and federal courts who have sued Monsanto and its parent company, Bayer, claiming exposure to Roundup caused their non-Hodgkin lymphoma.

Two cases have ended in verdicts totaling more than $150 million. Bayer has appealed one of the verdicts and is expected to appeal the second. A third trial is under way in Alameda County Superior Court.

In its interim review document, EPA called its cancer evaluation both "more robust than IARC's evaluation" and "more transparent."

In the interim document, EPA proposes label changes “to reduce off-target spray drift and establish a baseline level of protection … that is consistent across all glyphosate products. Reducing spray drift will reduce the extent of environmental exposure and risk to non-target plants and animals.”

EPA said although it is “not making a complete endangered species finding at this time, these label changes are expected to reduce the extent of exposure and may reduce risk to listed species whose range and/or critical habitat co-occur with the use of glyphosate.”

Among the label changes: Applicators must not spray during temperature inversions, and aerial applications cannot be made when wind speeds exceed 15 mph at the application site.

The public will have 60 days to comment on the document after a notice of its availability is published in the Federal Register. EPA anticipates releasing its interim decision by late summer or early fall, but it also said in the document released Tuesday that it could issue a final decision without releasing an interim decision.

In a news release, Bayer said it was reviewing the interim decision but called it “significant that the U.S. EPA and other expert regulators who have assessed the extensive body of science on glyphosate-based herbicides for more than 40 years continue to conclude that these products are safe when used as directed and that glyphosate is not carcinogenic.

"Bayer firmly believes that the science supports the safety of glyphosate-based herbicides, which are some of the most thoroughly studied products of their kind, and is pleased that the regulators tasked with assessing this extensive body of science continue to reach favorable conclusions,” the company said.

Reacting to the report Tuesday, the Natural Resources Defense Council's Jennifer Sass said, “EPA’s Pesticide office is out on a limb here — with Monsanto and Bayer and virtually nobody else. 

“Health agencies and credible non-industry experts who’ve reviewed this question have all found a link between glyphosate and cancer," Sass said. "EPA should take the advice of its own science advisors — who have rejected the agency’s no-cancer-risk classification.”

Sass is senior scientist with NRDC's Healthy People and Thriving Communities Program.

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This story has been updated with comments from Bayer.