A noteworthy development in the U.S. Environmental Protection Agency’s (EPA) ongoing and controversial consideration of the potential use of epidemiological data in its pesticide risk assessments occurred on May 25, 2017, when EPA placed in the public dockets for certain organophosphate (OP) pesticides an “update” of the September 15, 2015, Literature Review and Food Quality Protection Act (FQPA) determination, along with a response to comments on the original document.  These documents were signed by EPA scientists on December 29, 2016, prior to the new Administration, but were placed in the docket only last month, under the new Administration.  The documents attempt to rebut the various criticisms of EPA’s assessment of the epidemiology studies for chlorpyrifos and the original FQPA safety factor determination for OP pesticides, and they reaffirm the policy embodied in the original Literature Review.  Because these new documents were signed in the last days of the Obama Administration, they may be viewed by some industry stakeholders as an effort by some at EPA to “lock in” the prior policy concerning OP pesticides.

The public release of the “updated” Literature Review and response to comments must be considered in the context of the ongoing chlorpyrifos battles that have received significant public attention.  During the five months between the date that these “update” documents were signed and the date that EPA placed them in the public docket, EPA Administrator Pruitt issued a decision on March 29, 2017, to deny the petition filed by the Pesticide Action Network North America (PANNA) and the National Resources Defense Council (NRDC) requesting that EPA revoke all tolerances and cancel all registrations for chlorpyrifos products.  See EPA Denies Petition to Ban Chlorpyrifos.  In his denial decision, Administrator Pruitt concluded it would be appropriate for EPA to defer determining whether chlorpyrifos is likely to cause neurodevelopmental effects at exposure levels below the levels that cause acetylcholinesterase (AChE) inhibition until the completion of the registration review process for chlorpyrifos.  Administrator Pruitt based his decision on the premise that “the science addressing neurodevelopmental effects remains unresolved” and that “significant uncertainty … exists regarding the potential for chlorpyrifos to cause adverse neurodevelopmental effects.”

Some industry stakeholders may argue that the decision by the EPA scientists who prepared the “updated” Literature Review which concluded that EPA should retain the 10X FQPA uncertainty factor for OP pesticides can be reconciled with Administrator Pruitt’s subsequent denial decision, because the “updated” FQPA safety factor determination does not preclude further scientific discussion concerning the potential for neurodevelopmental effects from OP pesticide exposures.  On the other hand, other industry stakeholders may be concerned about the immediate adverse impact of this “updated” FQPA determination on the risk assessments prepared by EPA for OP pesticides and the measures that will be demanded by EPA to mitigate purported risks.

On April 5, 2017, PANNA and NRDC responded to Administrator Pruitt’s March 29, 2017, decision to deny their petition to revoke the tolerances and cancel the registrations for chlorpyrifos by submitting to the Ninth Circuit Court of Appeals a Motion for Further Mandamus Relief.  That motion was substantially based on the premise that EPA does not “suggest that it has reconsidered its finding that chlorpyrifos is unsafe.”  The briefing on the new mandamus motion was completed on May 5, 2017, several weeks before EPA disclosed the documents concerning the “updated” FQPA determination.  Nevertheless, petitioners could try to argue that these documents constitute further evidence supporting their key premise that EPA has not actually revisited its prior determination that chlorpyrifos exposures are unsafe.

The legal and policy issues posed by EPA’s evaluation of the epidemiological data for chlorpyrifos and by EPA’s determination that these data create sufficient uncertainty to warrant retention of the FQPA 10X safety factor for all OP pesticides will be a continued source of controversy, and will be watched with interest by all stakeholders.