By James V. Aidala and Lisa R. Burchi

On November 18, 2021, the United Farm Workers and several other non-governmental organizations (NGO) filed a petition with the U.S. Environmental Protection Agency (EPA) to revoke all food tolerances and cancel registrations for organophosphate (OP) pesticides (Petition). The Petition was filed pursuant to the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. Section 346a(d), the Administrative Procedure Act (APA), 5 U.S.C. Section 551, and the First Amendment Constitutional Right to Petition.

The Petition seeks final EPA actions to revoke tolerances and cancel registrations for 15 OPs by the registration review deadline of October 1, 2022.

The Petition also states that EPA must take the following actions:

• Update EPA’s human health risk assessments (HHRA) for OP pesticides to use a regulatory endpoint that the Petition claims will protect children from learning disabilities and other neurodevelopmental harm.
• Complete Endangered Species Act (ESA) consultations and ensure its registrations comply with the ESA;
• Conduct endocrine disruptor screening of all pesticides.
• Complete a cumulative risk assessment for all the OPs to address their cumulative acute poisoning and neurodevelopmental effects.

The Petition focuses on 15 OPs that are currently going through registration review:

• Acephate (EPA-HQ-OPP-2008-0915);
• Bensulide (EPA-HQ-OPP-2008-0022);
• Chlorethoxyfos (EPA-HQ-OPP-2008-0843);
• Chlorpyrifos-methyl (EPA-HQ-OPP-2010-0119);
• Diazinon (EPA-HQ-OPP-2008-0351);
• Dichlorvos (EPA-HQ-OPP-2009-0209);
• Dicrotophos (EPA-HQ-OPP-2008-0440);
• Dimethoate (EPA-HQ-OPP-2009-0059);
• Ethoprop (EPA-HQ-OPP-2008-0560);
• Malathion (EPA-HQ-OPP-2009-0317);
• Naled (EPA-HQ-OPP-2009-0053);
• Phorate (EPA-HQ-OPP-2007-0674);
• Phosmet (EPA-HQ-OPP-2009-0316);
• Terbufos (EPA-HQ-OPP-2008-0119); and
• Tribufos (EPA-HQ-OPP-2008-0883).

Commentary

Now that EPA is in receipt of the Petition, it must determine that it has received a “complete” petition to revoke a tolerance based on criteria set forth in EPA’s regulations (40. C.F.R. § 180.7). If EPA determines the Petition is complete, it will publish in the Federal Register within 30 days a notice of filing for the Petition, which must include the informative summary of the Petition submitted by the petitioner. FFDCA Section 408(d)(3). A public comment period follows.

Generally, the Petition is an important signaling document that the petitioners use to outline how EPA should approach the 2022 registration review deadline for these OP products. It signals that unless EPA completes all elements of a registration review, including a complete ESA assessment and an endocrine disruptor review -- which may be impossible for EPA to complete -- then EPA should act now to revoke OP tolerances in light of arguments contained in the Petition. It stresses the environmental justice commitments announced by the Biden Administration, arguing that evidence is clear, in their view, of the need to take immediate action to end OP use across virtually all of the members of the class. It seems to anticipate that even if EPA rolls out registration reviews of the individual OP pesticides before the deadline, there will likely be comment and debate about the specific analyses and evaluation of each member of the category. This would additionally delay the completion of any revised cumulative risk assessment for the OPs.

From the view of the petitioners, not only will EPA miss the 2022 deadline, but they also argue the evidence is sufficient now for EPA to take action to revoke tolerances for these compounds based on evidence already before EPA. Other stakeholders and EPA’s eventual analyses will dispute such conclusions, but completing registration review (as defined in the Petition) will likely be impossible to complete before next October. As a result, the Petition here suggests the template these advocacy groups will use to challenge continued registration of OP products past the 2022 deadline.

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By Lisa M. Campbell, Timothy D. Backstrom, and James V. Aidala

In September 2020, the U.S. Environmental Protection Agency’s (EPA) Office of Pesticide Programs (OPP) plans to convene a Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) meeting to discuss New Approach Methodologies (NAM) for organophosphate (OP) pesticides.  EPA states that these NAMs could reduce reliance on default uncertainty factors for human health risk assessment and also reduce animal testing.

Under Administrator Wheeler’s directive to prioritize efforts to reduce animal testing, EPA is developing NAMs based on in vitro techniques and computational approaches that will also provide the opportunity to incorporate information relevant to humans.  OPP states that it is evaluating use of “in vitro data for 16 organophosphate compounds to reduce potentially reliance on default risk assessment uncertainty factors in favor of more refined data-derived factors.”  Human health risk assessment for OP pesticides has recently been focused primarily on potential developmental neurotoxicity, and the Office of Research and Development (ORD) has been working to develop a NAM to evaluate developmental neurotoxicity.  Initial analyses of data derived from neuron cell models have been completed for specific OP pesticides as a case study and, when possible, compared to in vivo results (an in vitro to in vivo extrapolation).

This case study of a NAM for developmental neurotoxicity using OP pesticides will be presented to the FIFRA SAP at the September meeting for its consideration and advice.  EPA will request external review and public comment on this research before implementing NAMs in human health risk assessments.  Additional details, including dates, times and agenda, will be forthcoming at www.epa.gov/sap.

Commentary

EPA has for some time had a general policy that it will try to develop and to implement alternatives to in vivo animal testing.  These alternatives to animal testing are typically based on new in vitro assays and modeling methodologies.  It is interesting that OPP has selected an in vitro NAM to assess developmental neurotoxicity of OP pesticides as a case study, given the controversy surrounding EPA’s use of the default Food Quality Protection Act (FQPA) uncertainty factor for all OP pesticides, which was based primarily on epidemiology data that EPA claimed may suggest a link between chlorpyrifos exposure and developmental neurotoxicity.  Prior to this determination, human health risk assessment for OP pesticides was generally based on expert judgments by EPA that neurotoxicity would not be expected below the established threshold for acetylcholinesterase (AChE) inhibition, and that infants and children are not likely to be more sensitive to neurotoxic effects than adults.  OPP adopted the FQPA determination for all OP pesticides even though it could not determine or propose a mechanism for the presumed developmental neurotoxicity of chlorpyrifos below the threshold for AChE inhibition, or evaluate whether other OP pesticides might share a similar mechanism.  Since the 2015 release of the Literature Review, additional epidemiology studies have become available and a number of concerns regarding the reliability of the epidemiology data have been raised.  EPA has also expressed concerns with the availability and reliability of the epidemiology studies.  These developments bring into question the accuracy and reliability of the Literature Review.

In its announcement, OPP states that the new NAM is intended “to reduce potentially reliance on default risk assessment uncertainty factors,” although it does not state which uncertainty factors may be supplanted or modified.  Standard uncertainty factors which may be implicated include the factor for extrapolating from animal data to human effects (“interspecies variation”), the factor for human variability (“intraspecies variation”), and the default uncertainty factor for potential increased sensitivity of infants and children (“FQPA uncertainty factor”).  The issues may spark additional controversy.  Additionally, even if OPP and the FIFRA SAP conclude that the proposed NAM for developmental neurotoxicity is a viable approach to human health risk assessment for OP pesticides, there are likely to be many related policy issues.  For example, it is unclear whether OPP would be sufficiently confident in the reliability of such an assay to propose cancellation or suspension of affected pesticide products based on a resultant human health risk assessment.

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