On February 3, 2020, the U.S. Environmental Protection Agency (EPA) issued a Federal Register notice announcing the availability of an interim registration review decision for glyphosate.  EPA previously issued a proposed interim registration review decision (PID) for glyphosate for comment in April 2019.  At the time EPA issued the glyphosate PID for comment, EPA also issued a draft human health risk assessment and a preliminary ecological risk assessment for glyphosate.  After reviewing the comments received concerning these assessments, EPA has not made any revisions to either assessment.  EPA has determined that there are no dietary, residential, bystander, or occupational human health risks of concern associated with glyphosate use.   EPA has also determined that there are some potential risks to plants, birds, mammals, and invertebrates from glyphosate use, but that these can be appropriately mitigated by label changes requiring enforceable spray drift management measures and adding a warning concerning the potential hazards to non-target organisms.  EPA also has proposed some new measures to manage the development and spread of herbicide-resistant weeds.  EPA has generally retained the proposed labeling changes identified in the PID, except for some modest adjustments to the proposed language concerning droplet size restrictions and swath displacement restrictions for aerial applications, and removal of spray drift advisory language for airblast application.

Despite considerable publicity recently concerning purported carcinogenic risks for glyphosate, including allegations that human exposure to glyphosate can be linked to non-Hodgkin's lymphoma, EPA has determined that glyphosate is not likely to be a human carcinogen and has steadfastly adhered to this basic conclusion.  EPA made this determination for glyphosate after convening a meeting of the FIFRA Scientific Advisory Panel (SAP) to evaluate the carcinogenic potential of glyphosate in 2016.

The general purposes of the PID process are to allow EPA to move forward with aspects of the registration review process that are essentially complete, and to adopt interim risk mitigation measures, even though some of the actions required prior to a final registration review decision are not yet complete.  As in the case of most recent PIDs, EPA states that it has not yet made a complete determination concerning potential effects or any required consultation for glyphosate under the Endangered Species Act (ESA), nor has it made a determination for glyphosate under the Endocrine Disruptor Screening Program (EDSP).  In addition, EPA is considering a pending petition to prohibit preharvest use of glyphosate on oats, and to reduce the tolerance for glyphosate in oats, that was filed in 2018 by the Environmental Working Group and others.  This petition is predicated on the potential carcinogenicity of glyphosate.  Finally, EPA is still evaluating the question of whether additional data will be needed to evaluate properly the potential effects of glyphosate use on pollinators.  

More information on glyphosate and EPA’s interim registration review decision is available here.

Commentary

EPA's interim registration review decision for glyphosate is predicated on EPA's prior determination that the best available scientific data do not substantiate the claims that glyphosate may be a human carcinogen.  As discussed above, the potential carcinogenicity of glyphosate was thoroughly evaluated by the FIFRA SAP in 2016.  EPA's determination after that review that glyphosate is not a carcinogen has also been supported by other pesticide regulatory authorities.  Nonetheless, EPA's view conflicts with a cancer classification decision for glyphosate by the World Health Organization (WHO), and with some recent tort case decisions that were based on the premise that there is a credible linkage between glyphosate exposure and human cancer.  EPA recently announced that it would not permit or approve any cancer warning statements for inclusion in glyphosate labeling (including any statements that may be required pursuant to California's Prop 65) because EPA believes that such statements are false or misleading and would therefore cause the pesticides to be "misbranded."

It appears probable there will be continued litigation based on the purported carcinogenicity of glyphosate, along with various proposals to ban or restrict glyphosate use.  The pending petition to restrict use of glyphosate on oats that was filed by EWG, et al., is expressly predicated on the potential carcinogenicity of glyphosate, so it appears probable that this petition will ultimately be denied by EPA.  Nonetheless, unless WHO decides to reverse or modify its classification determination, or the courts determine that the recent tort awards for glyphosate users cannot be scientifically substantiated, the battles over the claimed carcinogenicity of glyphosate may persist for years.