By Lisa R. Burchi and Barbara A. Christianson

On December 2, 2021, the U.S. Environmental Protection Agency (EPA) announced it released the registration review schedule for the next four years through fiscal year (FY) 2025. While historically this schedule has been updated once each year, EPA states that going forward it will be updated on a quarterly basis.

The 2007 amendment of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires that EPA review each registered pesticide at least every 15 years. For the 726 pesticide cases that were registered before October 1, 2007, the amendment to FIFRA requires EPA to complete its review by October 1, 2022. This is significant, as it is intended to mark the end of the first 15-year registration review cycle.

Working toward that goal, EPA states that it has completed the following over the past 15 years:

• Issued more than 550 interim or final decisions;
• Completed more than 600 proposed interim decisions;
• Conducted more than 680 human health and ecological draft risk assessments (excluding endangered species assessments);
• Imposed new risk mitigation requirements for 51 percent of antimicrobial pesticides and 70 percent of conventional pesticides for which EPA issued an interim or final decision; and
• Canceled some or all uses in 120 cases.

EPA states its updated registration review schedule provides a “roadmap” for the next four years of EPA’s registration review program. EPA’s schedule includes 297 entries describing the registration review “action” (e.g., Draft Risk Assessment, Proposed Interim Decision, Interim Decision, Preliminary Work Plan, Final Work Plan) to be addressed by EPA’s different divisions (e.g., Pesticide Reevaluation Division; Antimicrobials Division, Biopesticides and Pollution Prevention Division). Throughout its review, EPA makes the information, assessments, and supporting material for each case available to the public at regulations.gov.

Significantly, but not surprisingly, EPA acknowledges that for some pesticides registered before October 1, 2007, it “anticipates that its review will extend beyond” the October 1, 2022, deadline “due to a number of challenges including delays in receiving data from registrants; the demands of responding to COVID-19; and a significant increase in recent years of resources devoted to litigation.” EPA also warns that the schedule is “subject to change based on shifting priorities and is intended to be an estimated timeline.” EPA notes further that data that are not submitted on time may affect EPA’s registration review timeline and that “several cases are not found on the schedule due to uncertainty of when necessary data will be received.”

Complying with the Endangered Species Act (ESA) is also part of the registration review process. Since 2007, EPA states that it has completed ESA assessments for certain high-priority pesticides and, in the coming years, plans to assess the effects of many more pesticides on endangered species in registration review. According to EPA, it will release its first ESA pesticides work plan in the coming months, which will outline steps EPA will take to come into compliance with the ESA in ways that are fair and transparent to the agriculture sector.

Information on EPA’s registration review process is available here.

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By Carla N. Hutton

On November 3, 2021, the U.S. Environmental Protection Agency (EPA), the White House Council on Environmental Quality (CEQ), the U.S. Department of Agriculture (USDA), the U.S. Department of Commerce, and the U.S. Department of the Interior “reaffirm[ed] their commitment to working together and with stakeholders to protect endangered species, provide effective pest control tools, and regulate pesticide use in a fair, transparent, and predictable manner.” According to EPA’s November 3, 2021, press release, on October 15, 2021, all five agencies met as part of the Interagency Working Group (IWG) created under the 2018 Farm Bill to discuss improvements to the consultation process for pesticide registration and registration review under Section 7 of the Endangered Species Act (ESA). EPA states that the group’s first meeting resulted in specific commitments to improve the pesticide consultation process for endangered species and engaging stakeholders, including by capitalizing on the strong interest among stakeholders for a workable process.

According to the press release, the IWG is optimistic about its ability to collaborate on improvements that the Biden Administration can implement. The IWG’s actions focused on improving processes that will contribute to tangible benefits for species conservation and for stakeholders. EPA states that the IWG “is intent to adopt improvements expeditiously and that endure across administrations.” To guide its future work, the IWG has identified the following initial priorities and approaches:

• Focus on improvements that deliver real world benefits for species conservation, public health, and food production. Examples include:
  • Use pilot projects to begin implementing mitigation measures as part of upcoming pesticide consultations and to demonstrate process improvements;
  • Adopt measures early in the pesticide consultation process to avoid, minimize, and offset the effects of pesticide use on ESA-listed species; and
  • Ensure that mitigation measures are effective and practical to implement;
• Consider opportunities to engage with stakeholders as an interagency body to complement the stakeholder activities of each agency; and
• Communicate the IWG’s work to stakeholders in a transparent manner.

EPA states that “[e]ffective endangered species protection cannot be accomplished solely by federal agencies,” but also requires “open and continuous engagement with stakeholders on practical solutions to harmonizing species conservation with pesticide use.” To that end, the IWG plans to hold its first stakeholder listening session in early 2022 and will provide details on the proposed session before the end of 2021.

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By Sheryl L. Dolan and Barbara A. Christianson

On August 25, 2021, the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) announced its release of a draft guide detailing the information requirements and process for submitting a Regulatory Status Review (RSR) request. Developers of certain genetically modified organisms may use the RSR process to determine the regulatory status of the organisms. The draft guide is open for public comment for 60 days. APHIS also will host a webinar to provide an overview of the draft RSR guide.

On May 18, 2020, APHIS published revised biotechnology regulations, codified in 7 C.F.R. Part 340 and referred to as the Sustainable, Ecological, Consistent, Uniform, Responsible, Efficient (SECURE) rule. For a discussion of the SECURE rule, please review Final SECURE Rule Will Update and Modernize USDA's Biotechnology Regulations. The revised regulations identify high-level information requirements for submissions to support RSR requests. In response to comments on the proposed SECURE rule, APHIS stated that it would publish detailed information requirements as a draft guide for public comment prior to issuing the draft guide in final.

The draft RSR guide is available on the APHIS website, at the bottom of the tab labeled The Regulatory Status Review Process, and also in the online docket. The public may submit comments at https://www.regulations.gov/docket/APHIS-2021-0062. APHIS states that it will consider all comments received by October 25, 2021, prior to issuing the final RSR guide. Additionally, APHIS will host a technical webinar on September 21, 2021, to discuss the RSR process and guide, and provide stakeholders the opportunity to ask questions. Registration is available now on the APHIS website.

Commentary

APHIS is authorized by the Plant Protection Act to evaluate potential plant pest risks resulting from certain organisms developed using genetic engineering techniques. Prior to the SECURE rule, developers of genetically modified plants could petition APHIS to seek a determination that a modified plant is unlikely to pose a plant pest risk and therefore is no longer subject to APHIS’ biotechnology regulations. With the SECURE rule, APHIS made several changes to its procedures, including introduction of the RSR process. The RSR process was implemented for select crops on April 5, 2021, and will be fully implemented for all crops on October 1, 2021.

Developers must submit a significant amount of technical information to APHIS to support a determination that a genetically modified plant can be deregulated. It typically is welcome news when regulators clarify the information that they need to make a regulatory determination, particularly given the time and resources invested in a new technology. A clear regulatory process, including information requirements and review timelines, allows industry to plan accordingly. The APHIS draft guide addresses information requirements, the review process, decision timelines, confidential business information justifications, and key definitions, and provides an optional submission template. It appears to be a useful tool in planning an RSR submission. We urge developers of genetically modified plants to review the guide carefully. If, following review, there are issues that require additional clarification, developers should highlight those issues in comments submitted to the docket linked above.

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By Lisa M. Campbell, Lisa R. Burchi, and James V. Aidala

On December 7, 2020, the U.S. Environmental Protection Agency (EPA) issued for comment the Proposed Interim Decision (PID) for chlorpyrifos.  85 Fed. Reg. 78849.  EPA announced it is proposing new risk mitigation measures to address potential human and environmental risks identified in EPA’s September 2020 draft risk assessments.  The PID proposes the following measures:

• Label amendments limiting application to address potential drinking water risks of concern.
• Additional personal protection equipment and application restrictions to address potential occupational handler risks of concern.
• Spray drift mitigation, in combination with the use limitations and application restrictions identified to address drinking water and occupational risks, to reduce exposure to non-target organisms.

EPA states that the PID presents proposed mitigation with the 10-fold (10x) Food Quality Protection Act (FQPA) safety factor, reflecting the uncertainties around doses that may cause pre- and post-natal neurodevelopmental effects.  Under FQPA, EPA evaluates new and existing pesticides to ensure they can be used with a reasonable certainty of no harm to infants, children, and adults.  EPA is required to consider the special susceptibility of children to pesticides by using an additional 10x safety factor unless adequate data are available to support a different factor.  EPA additionally included a FQPA factor of 1x to reflect the range of potential risk estimates of chlorpyrifos, as illustrated in the September 2020 draft risk assessments.

Comments on both the September 2020 draft risk assessments and the PID are due on or before February 5, 2021.  EPA states that by holding the comment period for both actions at the same time, the public has access to more information and can provide more informed, robust comments.  Comments can be submitted at EPA-HQ-OPP-2008-0850.

EPA announced that it will also consider the input and recommendations from the September 2020 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) meeting once it releases its report in December 2020.  Depending on the SAP’s conclusions, EPA may further revise the human health risk assessment. 

Commentary

The inclusion of both 1x and 10x calculations for the appropriate FQPA safety factor is unusual.  EPA states the final decision on the appropriate FQPA safety factor is partly dependent on any recommendations expected from the SAP meeting, which reviewed the “use of new approach methodologies (NAMs) to derive extrapolation factors and evaluate developmental neurotoxicity for human health risk assessment.”  This is part of a larger and longer evaluation of whether test methods that avoid using test animals can reliably substitute for current test guideline requirements, that is, whether it is appropriate to rely on in vitro test protocols to substitute for current in vivo testing protocols.

EPA’s articulation at this point in time of mitigation needed if the FQPA 10x safety factor is retained may indicate a prediction about the SAP’s likely recommendations.  It will be important to monitor developments on this issue closely.

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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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By Timothy D. Backstrom

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.

More information on glyphosate issues is available on our blog under keyword glyphosate.

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By Timothy D. Backstrom and James V. Aidala

On December 18, 2019, the Office of Pesticide Programs (OPP) of the U.S. Environmental Protection Agency (EPA) issued for comment a Proposed Interim Decision (PID) in the ongoing registration review process for each of the three registered triazine herbicides: atrazine, propazine, and simazine.  EPA will allow 60 days for comment on each of these triazine PIDs, but the specific comment deadline will only be established after EPA has published notice concerning the proposed interim decisions in the Federal Register.  EPA can utilize an “interim registration review decision” under 40 C.F.R. Section 155.56 whenever it is not yet ready to complete the registration review process, but EPA has nonetheless completed sufficient review to determine that new or interim risk mitigation measures are needed or that additional data or information should be submitted to complete the review.  For each of the three triazine herbicides, EPA is proposing to impose specific risk mitigation measures for particular registered uses to mitigate potential health and environmental risks.  For each triazine herbicide, EPA is not yet ready to make a final registration review decision because EPA has not made findings in the Endocrine Disruptor Screening Program (EDSP) or an effects determination under the Endangered Species Act (ESA).  Several key factors that will affect the final registration review decision for each of the triazine herbicides are discussed below.

Common Factors for Triazine Risk Assessment

There are several common factors to consider with regard to the triazines risk assessment.  These include:

1. Atrazine, propazine, and simazine are all included in the chlorotriazine chemical class.  EPA has determined that these three herbicides, along with three specific chlorinated metabolites, share a common mechanism of toxicity, so human health risks from all of these substances are being assessed by EPA together through one cumulative triazine risk assessment. The contribution of each product to aggregate human risk differs because of somewhat dissimilar use patterns. The combining of risks resulting from use of each triazine means, however, that it may be necessary for EPA to coordinate the ultimate registration review decisions for the three active ingredients.
2. As part of the ecological risk assessment for each triazine herbicide, EPA plans to make an effects determination for potentially vulnerable species under the ESA, which in turn will determine whether it is necessary for EPA to consult with the Fish and Wildlife Service or the National Marine Fisheries Service (the Services) concerning potential impacts of each active ingredient and relevant metabolites on endangered or threatened species.  Atrazine, propazine, and simazine are all included in a stipulated settlement between the parties in Center for Biological Diversity et al. v. EPA et al. No. 3:11 cv 0293 (N.D. Cal.), and EPA agreed in that stipulated settlement to set August 14, 2021, as the deadline for EPA to make a nationwide effects determination for each active ingredient, and to request any required consultation with the Services, under ESA Section 7(a)(2).
3. EPA states that the predominant human health effect of concern for all three of the triazine herbicides and their chlorinated metabolites is potential suppression of the luteinizing hormone (LH) surge, which is considered to be both a neuroendocrine and a developmental effect.  Atrazine and simazine were both included on List 1 for screening testing under the EDSP required by the Food Quality Protection Act (FQPA) amendments.   All of the required Tier 1 screening assays for each of these substances are complete and have been evaluated by EPA, but EPA has not yet made human health or environmental findings under the EDSP.  The EDSP screening testing has not been completed yet for propazine.

Risk Mitigation Measures

Each PID proposes specific risk mitigation measures intended to address potential human and environmental risks identified by the EPA risk assessments.

For atrazine, the PID includes the following measures to mitigate aggregate human risk:

• Reduce the permissible application rates for use of granular and liquid formulations on residential turf.
• Require additional personal protective equipment (PPE) and engineering controls for certain uses.
• Restrict aerial applications to liquid formulations only.
• Limit backpack sprayer applications to landscape turf to spot treatment only.
• Prohibit pressurized handgun application to certain commodities.

To mitigate ecological risks, the atrazine PID proposes to require various spray drift reduction measures, to add a non-target advisory statement to labeling, and to adopt a nationwide stewardship program.

For propazine, the PID proposes to cancel the greenhouse use to mitigate aggregate human risk.  Ecological risks would be mitigated by proposing to require various spray drift reduction measures and by adding a non-target advisory statement to labeling.

For simazine, the PID includes the following measures to mitigate aggregate human risk:

• Cancel simazine use on residential turf.
• Require additional PPE and engineering controls for certain uses.
• Limit pressurized handgun applications to certain commodities to spot treatment only.

Ecological risks would be mitigated by proposing to require various spray drift reduction measures and by adding a non-target advisory statement to labeling.

Commentary

In each of the PIDs for the triazine herbicides, EPA has focused its efforts on adopting mitigation measures which should be efficacious in reducing human and ecological risks without materially impairing the availability of the products in question for key agricultural uses.  In some instances, the PID documents explicitly state that the product registrants have agreed to proposed changes.  An EPA Pesticide Program Update dated December 19, 2019, that discusses the interim decision for atrazine includes statements of support from several grower groups.

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By Timothy D. Backstrom

On December 5, 2019, the U.S. Environmental Protection Agency (EPA) Office of Pesticide Programs (OPP) announced the availability of a revised interim registration review decision for use of sodium cyanide in the M-44 predator control device.  The M-44 device is a restricted use pesticide (RUP) and may be used only by certified applicators in compliance with specific mandatory restrictions set forth on the label.  Although the registration review process for sodium cyanide remains pending, EPA has decided to issue an interim decision for the M-44 device now to adopt new label restrictions intended to mitigate potential risks.  The revised interim decision adopts two new restrictions and also modifies certain existing restrictions, which EPA states "will reduce the potential for unintended impacts on humans, pets, and other non-target animals.”

The M-44 predator control device uses a spring-loaded ejector to fire a capsule containing a single lethal capsule of sodium cyanide.  The M-44 is used by livestock producers to control predators (primarily coyotes) that kill sheep, goats, and cattle.  Registrations for the M-44 device are currently held by the U.S. Department of Agriculture, and by five individual States (South Dakota, Texas, Montana, Wyoming, and New Mexico) where livestock predation has been a particular problem.

New or revised restrictions that will be incorporated in the approved labeling for the M-44 device include:

• Requiring a 600-foot buffer zone around residences where an M-44 cannot be used (except for a cooperating landowner who has given written permission).
• Requiring that the applicator notify occupants of all residences within a 0.5 mile radius (by face-to-face communication, person-to-person telephone communication, door hanger, or certified mail) prior to an M-44 placement.
• Increasing from 50 feet to 300 feet the distance from designated public paths and roads where M-44 use is prohibited.
• Requiring two elevated warning signs placed 15 feet from the M-44 device and facing the most likely directions of approach, instead of one elevated sign placed 25 feet from the device.

Commentary

Livestock producers and State departments of agriculture contend that the M-44 device is essential to limit economic losses resulting from predation, which reportedly amount to hundreds of millions of dollars annually.  In contrast, wildlife advocates have strongly opposed any continued use of the M-44 device.  In 2017, WildEarth Guardians and the Center for Biological Diversity petitioned EPA to suspend and cancel all registrations for M-44 capsules, but EPA concluded that the petition did not contain substantial new information and denied the petition in 2018.  Although the new and modified label restrictions adopted by EPA in the interim decision for the M-44 device are not likely to satisfy opponents, these changes should nonetheless reduce the likelihood that humans, pets, or other non-target species will be exposed to the M-44 capsules or the toxin they contain.

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By Lisa M. Campbell and Timothy D. Backstrom

On August 7, 2019, the League of United Latin American Citizens, Pesticide Action Network North America, Natural Resources Defense Council, and other petitioners (Petitioners) filed a new petition in the Ninth Circuit Court of Appeals seeking judicial review of United States Environmental Protection Agency (EPA) orders denying their request that EPA revoke all tolerances and cancel all registrations for chlorpyrifos.  On August 8, 2019, New York, California, Hawaii, Maryland, Vermont, Washington, Massachusetts, and the District of Columbia (States) also filed a new petition for judicial review concerning the refusal of EPA to ban chlorpyrifos.  The Petitioners and the States seek judicial review of the July 18, 2019, final order by EPA dismissing all objections to the initial decision by EPA to retain tolerances and registrations for chlorpyrifos, and of EPA’s March 29, 2017, order that initially denied a 2007 petition to revoke all tolerances and cancel all registrations for chlorpyrifos.

The Petitioners and the States also seek consolidation of their newly filed petitions for judicial review with currently pending chlorpyrifos litigation in LULAC, et al. v. Wheeler, et al.  As part of rehearing in the LULAC case, the Ninth Circuit vacated a prior decision that ordered EPA to cancel chlorpyrifos registrations, and instead issued a writ of mandamus requiring EPA to respond to objections to the 2017 denial order within 90 days.  EPA then issued the July 18, 2019, order denying all objections, along with a motion on July 19, 2019, to dismiss the LULAC case as moot.  EPA seeks dismissal of LULAC because it contends that the 2017 initial order was never itself reviewable, and EPA has now done everything that the writ of mandamus required. The Petitioners oppose the motion to dismiss because it would require the Court to take a position on a jurisdictional issue which they contend was not decided during rehearing.  The Petitioners and the States also argue that dismissal would be unnecessary and inefficient, requiring the challenging parties to reconstitute the record for review compiled in LULAC.

Petitioners also note that the Ninth Circuit retained jurisdiction when it issued mandamus in LULAC, and they request that their combined challenge to the EPA decision to retain the existing tolerances and registrations for chlorpyrifos be heard by the Court en banc as well.

Commentary

The latest petitions for judicial review of EPA’s 2019 decision to retain all tolerances and registrations for chlorpyrifos pending registration review were anticipated by all parties, and all parties agree that the procedural requisites for a judicial determination concerning the legality of EPA’s final decision to deny the 2007 administrative petition have now been satisfied.  The Petitioners and the States will likely argue that prior scientific determinations by EPA, including EPA analysis of epidemiology studies that purport to establish a link between exposure to chlorpyrifos and adverse neurodevelopmental effects in children, require that EPA proceed to revoke all tolerances and cancel all registrations for chlorpyrifos, while EPA will likely argue that difficult scientific issues concerning chlorpyrifos remain unresolved and should be addressed by EPA as part of the pending registration review for chlorpyrifos.

In addition to the dispute about combining the new petitions for review with the LULAC case, an interesting element of the latest filing by the Petitioners is that they attempt to bootstrap en banc review of the 2019 order in which EPA finally denied the administrative petition to revoke tolerances and cancel registrations for chlorpyrifos.  En banc review for an initial hearing (as opposed to en banc rehearing in a previously decided case) is allowed by the applicable appellate rules, but such review is disfavored and would be highly unusual.  Petitioners argue that it is warranted here because the en banc panel in the rehearing in the LULAC case reserved jurisdiction.  Given the motion by EPA to dismiss the LULAC case as moot, it can be presumed that EPA is likely to oppose this vicarious argument for en banc judicial review.   EPA can argue that the only reason the en banc panel retained jurisdiction was to assure that EPA would timely comply with the writ of mandamus that required EPA to rule on the objections within 90 days.

For further information on the long history of litigation concerning the petition to ban chlorpyrifos, please review our prior blog entries.

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

On August 2, 2019, the U.S. Environmental Protection Agency (EPA) Office of Pesticide Programs (OPP) announced that it has decided to reduce the Food Quality Protection Act (FQPA) safety factor for infants and children for pyrethroids from its current value of 3X to a new value of 1X.  This decision is based on a July 1, 2019, OPP report entitled “USEPA Office of Pesticide Programs’ Re-evaluation of the FQPA Safety Factor for Pyrethroids: Updated Literature and CAPHRA Program Data Review.”  Risk assessments incorporating the new lower FQPA safety factor for pyrethroids will be utilized in developing proposed registration review decisions for these compounds, and EPA has stated it will be taking public comment on the OPP report reducing the FQPA safety factor for pyrethroids after EPA publishes a notice of availability for the proposed registration review decisions.

Pyrethroids are a group of insecticides that includes natural pyrethrins (found in chrysanthemums) and more than 30 synthetic compounds with similar structure and activity. EPA has determined that it is appropriate to establish one FQPA safety factor for all pyrethroid active ingredients because these compounds all have the same mode of action and similar patterns of toxicity.  Pyrethroid insecticides are widely used in and around residential structures, on pets, in treated clothing, for mosquito control, and in various agricultural applications.  EPA indicates that although pyrethroids have relatively low mammalian toxicity, EPA believes that the principal concern for human risk assessment is a potential to cause acute neurotoxic effects.

The FQPA safety factor is intended to account for “potential pre- and post-natal toxicity and completeness of data with respect to exposure and toxicity to infants and children.”  The FQPA safety factor is set by statute at a default value of 10X, but EPA may select a lower value for this safety factor if EPA determines based on “reliable data” that such a lower value will be safe for infants and children.  This determination necessarily depends on EPA’s assessment of the quality of the data that address the susceptibility to adverse effects of the pesticide of infants and children.  Based on current EPA guidance, OPP evaluates the need for the default FQPA safety factor of 10X in two components: a safety factor of about 3X assigned to pharmacodynamic (PD) differences and a safety factor of about 3X assigned to pharmacokinetic (PK) differences.  PD differences refer to the sequence of events at the molecular or cellular level leading to a toxic response to a substance, while PK differences refer to absorption, distribution, metabolism, and excretion of the substance.

EPA previously evaluated the adequacy of the database concerning risks to infants and children posed by pyrethroid active ingredients in 2011.  At that time, EPA decided that there were sufficient data concerning the mechanism for potential neurotoxic effects of pyrethroids to allow EPA to reduce the factor for PD differences to 1X, but EPA retained the 3X factor for PK differences because EPA believed that the available pharmacokinetic data for pyrethroids was not sufficient for EPA to conclude that infants and children would not confront a greater risk of neurotoxic outcomes.  After EPA made the 2011 determinations, the Council for the Advancement of Pyrethroid Human Risk Assessment (CAPHRA) conducted a variety of additional research to address whether children are more sensitive to the neurotoxic effects of pyrethroid exposure, and this research assessed both PD and PK differences.  CAPHRA submitted a peer-reviewed physiologically based pharmacokinetic (PbPk) model for pyrethroids to EPA in 2018.  After reviewing the new CAPHRA data and the current public literature for pyrethroids, EPA has now concluded that the factor for PD differences should be maintained at 1X, but the factor for PK differences should be reduced from 3X to 1X.  Collectively, these determinations mean that EPA has concluded that there are reliable data to support a determination that infants and children are not more susceptible to the neurotoxic effects of pyrethroids than adults, so there is no need to retain either the default FQPA safety factor of 10X or the previous FQPA safety factor used for pyrethroids of 3X.

Commentary

The adoption by EPA of a new FQPA safety factor of 1X for all pyrethroid active ingredients will likely facilitate retention of existing use patterns and use directions for a large number of pyrethroid insecticides that are commonly used in and around human residences and workplaces.

From a larger perspective, the process by which EPA evaluated and selected a proposed FQPA safety factor for pyrethroids may be seen as typical for most pesticides or classes of pesticides.  The selection of a FQPA safety factor for a particular pesticide usually is based on review of available animal data, including PD and PK data, to determine whether there is any basis for concluding that infants and children may be more susceptible to adverse effects of that pesticide than adults.  Where EPA decides that the animal data addressing this question are insufficient, affected registrants and other proponents of registration can consult with EPA concerning studies that will address the uncertainties.  Depending on the outcome of such studies, EPA may be able to conclude that there is a scientific basis for a partial or complete reduction of the default FQPA safety factor.

Compared to this typical evaluation process, the recent decision by EPA to retain the default FQPA safety factor for all organophosphate (OP) active ingredients, which was based on EPA’s interpretation of neurodevelopmental effects reported at low exposure levels (below the threshold for acetylcholinesterase inhibition) in epidemiology studies for chlorpyrifos, may be seen as an aberration.  EPA’s decision to rely on epidemiology studies that may be susceptible to methodological biases, and the decision to utilize epidemiology studies for chlorpyrifos to set the FQPA safety factors for all OP pesticides, have both been controversial.

EPA’s recent decision to retain the current tolerances and registrations for chlorpyrifos was based in significant part on EPA’s interpretation of a PbPk model for chlorpyrifos previously submitted by DowAgro (now Corteva), which mitigated to some degree EPA’s retention of the default FQPA safety factor for chlorpyrifos.  Corteva may submit further data addressing PD and PK differences for chlorpyrifos, and EPA has also stated that it intends to review some new animal studies for chlopyrifos, which purport to show neurodevelopmental effects at low exposure levels.  Perhaps these data will allow EPA to establish a point of departure (POD) for chlorpyrifos risk assessment without any need for a further excursion into the unfamiliar risk assessment territory represented by EPA’s use of epidemiology data for chlorpyrifos.

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