Bergeson & Campbell, P.C. serves small, medium, and large pesticide product registrants and other stakeholders in the agricultural and biocidal sectors, in virtually every aspect of pesticide law, policy, science, and regulation.

By Lynn L. Bergeson and Carla N. Hutton

On October 19, 2018, the U.S. Environmental Protection Agency (EPA) posted the Final Work Plan (FWP) for the nanosilver registration review process under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).  The FWP explains what the Office of Pesticide Programs (OPP) “knows about nanosilver generally, highlighting anticipated data and assessment needs for each unique nanosilver chemistry, identifying the types of information that would be especially useful to the Agency in conducting the review, and providing an anticipated timeline for completing review of the nanosilver case.”  According to the FWP, EPA has identified the following use patterns to date:  swimming pool/spa treatments; and material preservative products for coatings, textiles, and plastics.  The FWP states that people may be exposed to nanosilver through inhalation and dermal exposures while applying the products to swimming pools and from incidental oral exposures during swimming.  Further exposures may come from material preservative uses either while applying or from nanosilver that leaches out when textiles and plastics are washed.  Nontarget organisms can be exposed when swimming pool water is released or when nanosilver used as a material preservative leaches.  

According to the FWP, EPA “anticipates the need to require generation and submission of human health hazard and exposure data and to conduct a human health risk assessment for nanosilver during registration review.”  The FWP states that EPA plans to conduct an environmental risk assessment for the nanosilver uses, “particularly focusing on materials preservative uses, such as plastics and textiles if the particular nanosilver chemistries are shown to leach, and swimming pool uses.”  Any of the other use patterns may also be subject to ecological assessment if the fate and product chemistry profiles indicate the potential for environmental exposures.  According to the FWP, the risk assessment integrates the environmental fate and effects data to determine if any uses pose risks to nontarget organisms.  Potential risks to fish, aquatic invertebrates, aquatic plants, and birds and mammals will be assessed after the data gaps specified in the FWP are satisfied and the relevant data are available.

EPA invites any label amendments that could be considered to eliminate the anticipated need to require certain data, reduce the possibility that EPA’s planned risk assessments overestimate risk due to reliance on conservative assumptions, and/or improve label clarity.  EPA anticipates issuing in 2018 a DCI requiring the data set out in Table 7 of the FWP, “Studies Anticipated as Needed for Nanosilver Registration Review.”


 

By Margaret R. Graham

On October 10, 2018, EPA’s Office of Pesticide Programs (OPP) announced that it will be holding a public meeting of the Pesticide Program Dialogue Committee (PPDC) on October 31, 2018, from 8:30 a.m. to 5:00 p.m., and that on November 1, 2018, from 8:30 a.m. to 12:00 p.m., it will be hosting an informational seminar on biotechnology-pesticide issues for stakeholders.  83 Fed. Reg. 50921.  The PPDC meeting and informational seminar will be held at 1 Potomac Yard South, 2777 S. Crystal Dr., Arlington, Virginia, in the lobby-level Conference Center.  EPA’s draft agenda for the PPDC meeting has been posted to the PPDC website.

The PPDC meeting agenda lists the following seven sessions: 

  1. Pesticide Registration Improvement Act (PRIA) -- session goal is to “provide the PPDC with an update on EPA’s progress in implementing PRIA”;
  2. Smart Label Project/e-CSF -- session goal is to “provide the PPDC with an overview the electronic pesticide label, the benefits to EPA and stakeholders, and next steps”;
  3. Emerging Application Technologies -- session goal is “to inform the PPDC about how new unmanned aerial vehicle (UAV) technology is working in the field for pesticide applications and how this new technology may benefit the agricultural sector”;
  4. Benefits of Biological Products: Industry Perspective -- session goal is to explain “BPPD’s focus on low risk products and biopesticides, how EPA encourages low risk products by having a different division and registration timelines and costs” and “how pesticides, whether conventional or biological, are reviewed with rigor and held to the same safety standard”;
  5. Integrated Mosquito Management Training -- session goal is to “provide awareness of on-line training and manual (in English and Spanish) focusing on Integrated Mosquito Management created by AMCA with funding by the Centers for Disease Control and Prevention”;
  6. Public Health Workgroup -- session goal is to “report on the progress of the group’s Emergency Preparedness Plan and solicit feedback”; and
  7. 21st Century Toxicology: OPP’s Efforts on Non-Animal Alternative Testing for the Acute 6-Pack -- session goal is to “update the PPDC on OPP’s recent progress toward the reduction of animal use in testing, and the implementation of alternative methods.”

Nancy Beck, Ph.D., Deputy Assistant Administrator of the Office of Chemical Safety and Pollution Prevention and Richard Keigwin, OPP Director, will make the opening remarks.  After the sessions, EPA is providing a 15-minute window for public comments.  PPDC meetings are free, open to the public, and no advance registration is required.


 

By James V. Aidala and Margaret R. Graham

On September 28, 2018, the U.S. Environmental Protection Agency (EPA) announced it was accepting public nominations of scientific experts to be considered for ad hoc participation on the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) through membership on the Food Quality Protection Act (FQPA) Science Review Board (SRB).  83 Fed. Reg. 49091.  EPA states that “all nominees will be considered for ad hoc participation providing independent scientific advice to the EPA on health and safety issues related to pesticides”  and requests that any individuals nominated have expertise in one or more of the following areas:  biochemistry; chemistry; epidemiology; human health risk assessment; pathology; physiologically based pharmacokinetic (PBPK) modeling; aquatic modeling; pharmacology; ecological risk assessment; environmental exposure and fate; environmental toxicology; occupational, consumer, and general exposure assessment; toxicology; dose response modeling; environmental engineering; statistics; water quality monitoring; hydrologist; Geographic Information Systems (GIS) specialist; computational toxicology; entomology; veterinary entomology; medical entomology, insect ecology, allergenicity, research veterinarian; inhalation toxicology; volatile organics; endocrinology, alternative testing methods, high throughput testing approaches, adverse outcome pathways, cross species extrapolation, and systematic review.  The Designated Federal Officer’s to whom nominations should be provided is listed in the Federal Register notice.  Nominations are due by November 13, 2018

Commentary

FPQA added this SRB to the previous authorization for the SAP to recognize the expanding universe of scientific questions which often underlie issues surrounding pesticide registration.  The FQPA amendment simply adds that “60 scientists who shall be available to the SAP” without specifying any particular disciplines or skills which might be useful to assist with the deliberations and review by the SAP.  This was intended to continually allow EPA to adapt to changing or evolving scientific questions without constantly tinkering with the membership of the SAP itself.  At the same time, it allows these ad hoc members to be recognized for their contributions and to be compensated in the same manner as SAP members.  


 

By Lisa R. Burchi and Lisa M. Campbell

On September 25, 2018, the U.S. Environmental Protection Agency’s (EPA) Office of Inspector General (OIG) issued a report Measures and Management Controls Needed to Improve EPA’s Pesticide Emergency Exemption Process that details the results from the its audit done to determine whether EPA has a comprehensive pesticide emergency exemption approval process that maintains environmental and human health safeguards.  Section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) allows EPA to “grant federal and state lead agencies the authority to approve -- in certain emergency situations -- the limited application of a pesticide not registered for that particular use.  These short-term pesticide use approvals are called emergency exemptions.”  OIG states that the scope of the audit “focused on the emergency exemption management process and the internal controls necessary to consistently implement and administer it.”  OIG did not “evaluate the science used to review emergency exemptions or the subsequent emergency exemption application decisions.”

OIG’s main criticisms of EPA’s emergency exemption program listed in the report are:

  1. EPA’s Office of Pesticide Programs (OPP) collects human health and environmental data through its emergency exemption application process, including the total acres affected, the proposed and actual quantities of the exempted pesticide applied, and the estimated economic losses but it does not use these data to support outcome-based performance measures that capture the scope of each exemption, to measure the potential benefits or risks of each exemption, or to determine how well the emergency exemption process maintains human health and environmental safeguards.
  2. OPP does not consistently communicate emergency exemption information with its stakeholders.  OPP previously sent a “year in review” letter to states that summarized the emergency exemption activity for that year and provided additional information regarding the emergency exemption process.  OPP has not sent this letter since 2015, however.
  3. There were significant deficiencies in the OPP’s online database management, in its draft Section 18 emergency exemption standard operating procedure and application checklist, and in its reports to Congress and the Office of Management and Budget.

The eight OIG recommendations in the report for the Assistant Administrator (AA) for the Office of Chemical Safety and Pollution Prevention’s (OCSPP) consideration, and OCSPP’s response to those recommendations, are as follows:   

Recommendation 1:  Develop and implement applicable outcome-based performance measures to demonstrate the human health and environmental effects of the EPA’s emergency exemption decisions.

  • OCSPP Response and OIG Resolution:  OCSPP did not agree with this recommendation, stating that development of an outcome-based performance measure for the Section 18 emergency exemption process was neither appropriate nor feasible.  No proposed corrective actions were proposed and this issue remains unresolved. 

Recommendation 2:  Determine which application review performance target for emergency exemption applications the OPP plans to meet, and make that target consistent between its Annual Performance Goal and its internal controls governing the emergency exemption process.

  • OCSPP Response and OIG Resolution:  OCSPP did not agree or disagree with Recommendation 2, but it nevertheless provided a corrective action “to avoid future confusion” and a completion date (July 31, 2019) that was considered acceptable to OIG.

Recommendation 3:  Update and prepare the draft standard operating procedure in final that OPP uses to guide the emergency exemption process.

  • OCSPP Response and OIG Resolution:  OCSPP agreed with this recommendation and provided planned corrective actions and a completion date (July 31, 2019) that was considered acceptable to OIG.

Recommendation 4:  Develop formal emergency exemption application review procedures that detail specific data collection, management and reporting control steps, and procedures that require specific management controls for accurately and consistently updating the OPP’s Section 18 database.

  • OCSPP Response and OIG Resolution:  OCSPP agreed with this recommendation and provided acceptable planned corrective actions and a completion date (July 31, 2019) that was considered acceptable to OIG.

Recommendation 5:  Develop concise emergency exemption application guidance that specifies the minimum requirements of an application submission and is available on the OPP’s Section 18 website.

  • OCSPP Response and OIG Resolution:  OCSPP did not agree or disagree with Recommendation 2, but it nevertheless proposed to:  (1) evaluate how its web resources can be enhanced to respond to this recommendation; and (2) if it determines that enhancements to the Section 18 website are necessary, implement any needed web updates by December 2019.  OIG does not believe the proposed corrective action for this recommendation is sufficient to meet the intent of the recommendation and states this recommendation remains unresolved.

Recommendation 6:  Provide clear guidance to state lead agencies on how and when they can use efficacy data from other state lead agencies to satisfy the emergency exemption application criteria.

  • OCSPP Response and OIG Resolution:  OCSPP did not agree with this recommendation, stating that the only example provided by OIG to support this recommendation represents an extremely rare situation.  No corrective actions were proposed and this issue remains unresolved. 

Recommendation 7:  Expand the data presented in the OPP’s Section 18 database by considering additional data points, such as application acreage requested, actual acreage applied, and registration status of each exempted pesticide.

  • OCSPP Response and OIG Resolution:  OCSPP agreed with this recommendation and stated it would “consider additional data points, such as application acreage requested, decision documents, and registration status of each exempted pesticide, as OCSPP explores ways to improve the website database and its overall content.”  OCSPP proposed that by December 2019 recommendations would be made to the OPP Director for enhancing the Section 18 database and a memorandum would be provided to the OCSPP AA with a plan for updating the Section 18 database addressing these recommendations.  OIG states that OCSPP did not commit to expanding the data presented in the Section 18 database and, thus, this issue remains unresolved.

Recommendation 8:  Provide an annual update and information summary to state lead agencies to better inform them about any changes to the emergency exemption application-and-review process.

  • OCSPP Response and OIG Resolution:  OCSPP agreed with this recommendation and stated it would “explore how to provide periodic and useful program updates to applicants.”  OCSPP proposed by that December 2019 it would “work with State Lead Agencies to identify the types of information they may find helpful for periodic updates” and “develop a strategy which details the activities that might be conducted to provide periodic and useful program updates to applicants.”  OIG states that OCSPP found the term “periodic” unclear and stated the issue remains unresolved.

Although several of these recommendations and EPA’s proposals remain unresolved, registrants should monitor for actions to be taken by EPA in response to the OIG Report. 


 

By Timothy D. Backstrom and Lisa M. Campbell 

On September 24, 2018, in the U.S. Court of Appeals for the Ninth Circuit (Ninth Circuit), respondents U.S. Environmental Protection Agency (EPA) and Acting EPA Administrator Andrew Wheeler (collectively EPA) petitioned for an en banc and panel rehearing concerning the Ninth Circuit’s August 9, 2018, decision that granted judicial review of EPA’s initial order denying an administrative petition by the Pesticide Action Network North America (PANNA) and the Natural Resources Defense Council (NRDC) to revoke all tolerances and cancel all registrations for chlorpyrifos, and that specifically directed EPA to revoke all tolerances and cancel all registrations for chlorpyrifos within 60 days.  More information regarding the August 9 decision is available in our blog item “Ninth Circuit Directs EPA to Revoke all Tolerances and Cancel All Registrations for Chlorpyrifos.”

EPA’s petition for rehearing sets forth three discrete procedural arguments as to why rehearing should be granted.  The first argument is that the panel erred because “an initial decision denying an administrative petition under 21 U.S.C. § 346a(d)(4)(A)(iii) is simply not within the jurisdiction of this Court to review ….”  EPA contends that the decision to grant judicial review of the initial EPA order, without waiting for EPA to respond to objections or to issue a final order, conflicts with the applicable precedent in both the Ninth Circuit and the U.S. Court of Appeals for the Second Circuit (Second Circuit).

EPA’s second argument is that, even if the initial EPA order is deemed to be reviewable, the panel’s decision directing EPA to take specific actions on remand “exceeded the remedial authority granted the courts by Congress” and conflicts with applicable Supreme Court precedent.  EPA identifies some other actions that EPA could hypothetically have decided to take on remand, including denying the administrative petition based on a finding that the Federal Food, Drug, and Cosmetic Act (FFDCA) safety standard is met, reducing the affected tolerances, or revoking only certain tolerances.  EPA argues that the court was not empowered to direct EPA to take specific actions, but should have instead remanded the matter to EPA “for further consideration in light of the panel’s holding that EPA may not ‘decline to revoke chlorpyrifos tolerances [without] mak[ing] a finding of reasonable certainty that the tolerances were safe.’”

EPA’s third argument is that, in the event a broader rehearing is not granted, a rehearing by the panel should nonetheless be convened to modify the relief ordered under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).  EPA argues that revocation of the chlorpyrifos tolerances would not lead automatically to cancellation of all chlorpyrifos registrations, because there are also some non-food uses for chlorpyrifos.  EPA states that “FIFRA incorporates the safety standard of the FFDCA only with respect to food-use pesticides …” (emphasis in original).  EPA also notes that EPA lacks authority to comply with the court’s order to cancel all chlorpyrifos registrations within 60 days, because EPA must follow the statutory procedure for cancellation under FIFRA Section 6(b), which requires EPA to forward a proposed cancellation first to the U.S. Department of Agriculture (USDA) and the FIFRA Scientific Advisory Panel (SAP), and to afford the affected registrants and other adversely affected persons an opportunity to request an adjudicatory hearing to contest the proposed cancellation.  EPA states that the panel should provide at least a limited rehearing, because it granted relief without the benefit of any prior briefing on remedy in which these significant problems would have been identified.

Commentary

Although parties to appellate litigation often seek rehearing or rehearing en banc, federal agencies represented by the U.S. Department of Justice (DOJ) are considerably more selective about the circumstances in which they will file a petition for rehearing.  There are some compelling arguments supported by precedent that judicial review is not available under the FFDCA for the type of initial order concerning which the petitioners in this case sought review.  Moreover, EPA has identified some practical factors which make it literally impossible for EPA both to adhere to mandatory statutory procedures under FIFRA and to comply with the terms of the court’s order.  For this reason, even if a broader rehearing is not granted concerning the jurisdictional question or the authority of the court to order EPA to take specific actions, a narrower rehearing before the appellate panel may be ordered, which would allow the parties an opportunity for further briefing on remedy and permit the court to modify its order.

More information on chlorpyrifos issues, including further proceedings in this case, is available on our blog under key word chlorpyrifos.


 

By Timothy D. Backstrom and Lisa M. Campbell

On September 19, 2018, the California Department of Pesticide Regulation (DPR) proposed a regulation to designate chlorpyrifos as a toxic air contaminant (TAC).  DPR states that this proposal is being presented “after an extensive period of scientific and public review.”  The proposed rule is based on a final evaluation issued in July 2018, in which DPR’s Human Health Assessment (HHA) Branch determined that chlorpyrifos meets the quantitative criteria for designation as a TAC.  To make that determination, DPR utilized an inhalation reference concentration (RfC) based on new animal studies with chlorpyrifos that reported neurodevelopmental effects at exposure levels well below the threshold for acetylcholinesterase (AChE) inhibition.  More information on DPR’s final TAC evaluation is available in our blog item "California DPR Releases Final Toxic Air Contaminant Evaluation for Chlorpyrifos."  In August 2018, DPR posted the Scientific Review Panel on TAC’s findings on chlorpyrifos and the Director’s Proposed Determination Concerning Chlorpyrifos as a TAC.

DPR is providing a 45-day public comment period (until November 9, 2018) on the proposed regulation to list chlorpyrifos as a TAC.  Written comments may be submitted to .(JavaScript must be enabled to view this email address).  In addition, DPR is holding a hearing to receive oral comments on this issue on November 8, 2018, at 2:00 p.m. (PT) at the California Environmental Protection Agency headquarters, 1001 I Street, in Sacramento, California.  DPR states that it anticipates that the proposed regulation to list chlorpyrifos as a TAC will be effective in 2019.  Even though DPR is proposing to list chlorpyrifos as a TAC, DPR states that “possible mitigation measures to protect human health and the environment will be considered through a subsequent process involving consultation with other state and local agencies including the Office of Environmental Health Hazard Assessment (OEHHA) and the California Air Resources Board (CARB).”

Commentary

The U.S. Environmental Protection Agency (EPA) previously issued a determination that the default 10X safety factor for infants and children established by the Food Quality Protection Act (FQPA) should be retained for chlorpyrifos.  This determination was based primarily on epidemiology studies that purported to show adverse neurodevelopmental outcomes in humans at exposure levels below the threshold for AChE inhibition, but the methodology used in these epidemiology studies has been harshly criticized by the pesticide industry.  In contrast, the DPR TAC proposal is predicated on a determination that new animal studies with chlorpyrifos report neurodevelopmental effects below the threshold for AChE inhibition, and DPR views the epidemiology studies utilized by EPA to make its FQPA determination as providing corroboration for the animal data.  At this juncture, it is not clear how EPA will characterize the new animal data concerning chlorpyrifos.  In any case, questions are likely to remain concerning EPA’s use of data concerning chorpyrifos to establish the FQPA safety factor for other organophosphate (OP) pesticides.

More information on chlorpyrifos issues and California DPR regulations is available on our blog.


 

By Margaret R. Graham

On September 20, 2018, the U.S. Environmental Protection Agency (EPA) announced it would be hosting a webinar titled “Best Practices for Ground Application” on October 25, 2018, from 2:00 p.m. to 3:30 p.m. (EDT).  The announcement states that this webinar is tailored for “growers, pesticide applicators, pest management professionals, and other interested stakeholders who work in crop production.”

The webinar will be presented by Dr. Greg Kruger, a weed science and application technology specialist from the University of Nebraska-Lincoln and will cover different methods of ground application, best practices for reducing pesticide spray particle drift when using ground application equipment, and a discussion of the optimization of weed control.  Registration is available online.

More information on other pesticide applicator issues, including the Worker Protection Standard, is available on our blog.


 

By Lisa M. Campbell and Lara A. Hall, MS, RQAP-GLP

On August 21, 2018, the U.S. Environmental Protection Agency (EPA) announced it was posting new frequently asked questions (FAQ) for registrants and contract laboratories conducting honeybee toxicity testing.  EPA states that these FAQs are “made up of responses to inquiries EPA commonly receives about protocols used to generate honeybee toxicity data for submission in support of pesticide registration,” and are “meant to complement the Agency’s existing Pollinator Risk Assessment Guidance and increase the transparency and clarity of the risk assessment process.”  The FAQs include general study questions and questions related to specific kinds of contact toxicity, oral toxicity, chronic toxicity, toxicity of residues on foliage, and field and tunnel colony toxicity levels.  Questions not found in the FAQs or risk assessment guidance can be submitted to .(JavaScript must be enabled to view this email address).


 

By Lisa M. Campbell and Timothy D. Backstrom

On August 9, 2018, the majority of a three-judge panel of the U.S. Court of Appeals for the Ninth Circuit (Ninth Circuit) issued an opinion in the latest chlorpyrifos case (League of United Latin American Citizens (LULAC) v. Wheeler, No. 17-71636) granting the petition for review of a 2017 order by the U.S. Environmental Protection Agency (EPA) that denied an administrative petition to revoke the tolerances for chlorpyrifos; vacating the 2017 order; and remanding the matter back to EPA with explicit directions to EPA to “revoke all tolerances and cancel all registrations for chlorpyrifos within 60 days.”  A separate dissent stated that the court should have dismissed the case for lack of jurisdiction.  Please see our blog item “EPA Denies Petition to Ban Chlorpyrifos” for more information on EPA’s denial of the petition in 2017.

EPA argued in its brief that the court lacks jurisdiction to review the 2017 order denying the petition to revoke the tolerances for chlorpyrifos because Section 408(g)(2)(C) of the Federal Food, Drug, and Cosmetic Act (FFDCA) requires EPA to rule on administrative objections to its denial of the petition to revoke the tolerances for chlorpyrifos before judicial review is available under FFDCA Section 408(h)(1).The majority opinion rejected this argument, stating that FFDCA Section 408(h)(1) “does not ‘clearly state’ that obtaining a section (g)(2)(C) order in response to administrative objections is a jurisdictional requirement.” Rather than a jurisdictional limitation, the majority construed the objections process in FFDCA as a non-jurisdictional “claims-processing rule.”In contrast, the dissenting judge agreed with EPA’s argument that the court lacks jurisdiction to review this matter until after EPA responds to the objections to the 2017 order.

After concluding that the objections process is not jurisdictional in character, the majority next considered whether the petitioners should nonetheless be required to exhaust their administrative remedies by waiting until EPA responds to their objections before obtaining judicial review.Although FFDCA Section 408(g)(2)(C) requires EPA to rule on the objections “as soon as practicable,” EPA had taken no action for 13 months after the objections were filed.The majority concluded that the exhaustion requirement should be waived “in light of the strong individual interests against requiring exhaustion and weak institutional interests in favor of it.”

EPA did not specifically address the substantive merits of the 2017 order in its brief, and the majority found that EPA has consequently “forfeited any merits-based argument.”The 2017 order was issued in the context of an administrative record in which EPA has repeatedly determined that the FFDCA standard for maintenance of chlorpyrifos tolerances (“a reasonable certainty that no harm will result from aggregate exposure to the pesticide”) could not be met because of the risk of neurodevelopmental effects. The standard for registration under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) incorporates this same FFDCA standard. Although the 2017 order stated that “the science addressing neurodevelopmental effects is unresolved,” it did nothing to alter these prior EPA determinations. The majority noted that EPA’s assertion that “significant uncertainty” remains regarding the health effects of chlorpyrifos being directly at odds with the “reasonably certainty” standard and “therefore mandates revoking the tolerance under [FFDCA Section 408(b)(2)(A)(i)].” The majority concluded that the possibility that future evidence may contradict EPA’s current determinations cannot justify continued inaction, and that the failure of EPA to proceed with the revocation of the tolerances and the cancellation of the registrations for chlorpyrifos “has now placed the agency in direct contravention of the FFDCA and FIFRA.”

Commentary

The court’s direct instruction requiring EPA to proceed promptly with revocation of all tolerances and cancellations of all registrations for chlorpyrifos represents an unusually aggressive judicial intervention in the administrative process.Nevertheless, this outcome must be viewed in the context of an eleven year history beginning with an administrative petition that requested the same relief, followed by a writ of mandamus in 2015 from the same court requiring EPA to make a prompt decision on the petition.Although substantial controversy remains concerning the correct interpretation of epidemiology studies with chlorpyrifos, it appears that the court believes that EPA has not taken any action that would support a change in EPA’s prior conclusion that these studies constitute evidence of potential neurodevelopmental effects in children at chlorpyrifos exposure levels below the threshold for acetylcholinesterase (AChE) inhibition. Had EPA’s 2017 denial of the administrative petition been accompanied by an amended risk assessment for chlorpyrifos which articulated a changed conclusion, the court may have been less likely to substitute its judgment for that of EPA.The court seemed to find that because the scientific assessments in the current administrative record could not support the “reasonable certainty” standard in the FFDCA, the conclusion it reached on the merits was unavoidable.

Please see our blog item “Oral Argument Held in Case Challenging EPA’s Denial of Petition to Revoke Chlorpyrifos Tolerances” for information on the oral argument that took place on July 9, 2018, and the briefing in this case.  Further information on the case proceedings is available on our blog under key word chlorpyrifos.


 

By Lisa M. Campbell and Timothy D. Backstrom

In July 2018, the California Environmental Protection Agency’s Department of Pesticide Regulation (DPR), Human Health Assessment (HHA) Branch, issued its final toxic air contaminant (TAC) evaluation of chlorpyrifos.  This final TAC evaluation updates the December 2017 draft evaluation of chlorpyrifos as a TAC for the Scientific Review Panel (SRP) which updated the August 2017 draft and was reviewed by the SRP on TACs, and incorporates certain changes based on SRP recommendations.  As part of their review of the December 2017 draft, the SRP recommended “additional and detailed review of developmental neurotoxicity studies, in particular recent in vivo animal studies as well as a more in depth analysis of human effects of chlorpyrifos” and “that DPR reevaluate the critical endpoints, the associated [(uncertainty factors (UF)], and the resulting [reference concentrations (RfC)] and [reference doses (RfD)] for each endpoint.”

DPR determines that a pesticide is a TAC for a non-cancer adverse effect if the projected air concentrations associated with use of the pesticide are more than one tenth of the inhalation RfC established based on animal toxicity and epidemiology data.  In the draft TAC evaluation for chlorpyrifos, DPR utilized the threshold for red blood cell acetylcholinesterase (AChE) inhibition in humans and a target margin of exposure (MOE) of 100, including a factor of 10 intended to account for potential neurodevelopmental effects below the threshold for RBC AChE inhibition.  In the final TAC evaluation for chlorpyrifos, DPR increased the MOE for AChE inhibition to 300, based on deficiencies in the human inhalation parameters used to model the threshold for AChE inhibition.

In addition, the final TAC evaluation establishes a new No Observed Effect Level (NOEL) for neurodevelopmental effects in animal studies with chlorpyrifos reported at exposure levels well below the threshold for AChE inhibition.  Based on this NOEL, DPR has derived a new inhalation RfC for neurodevelopmental effects, using a standard MOE of 100 consisting of 10X for interspecies sensitivity and 10X for intraspecies variability.  This new inhalation RfC based on neurodevelopmental effects in animal studies is about one-half the revised inhalation RfC based on the threshold for AChE inhibition.  Because the modeled spray drift air concentrations for chlorpyrifos are more than one tenth of this new inhalation RfC, DPR concludes “that chlorpyrifos meets the criteria to be listed as a TAC pursuant to the law of California.”

Commentary

In the final TAC evaluation for chlorpyrifos, DPR concluded that there is sufficient evidence from animal studies to establish a new NOEL for neurodevelopmental effects, which is well below the level that has been shown to cause AChE inhibition in the same animals.  Although the U.S. Environmental Protection Agency (EPA) has previously issued a determination that the default 10X safety factor for infants and children established by the Food Quality Protection Act (FQPA) should be retained for chlorpyrifos, this determination was based on epidemiology studies that purported to show adverse neurodevelopmental outcomes in humans at exposure levels below the threshold for AChE inhibition.  The methodology used in these epidemiology studies has been harshly criticized by the pesticide industry.  DPR views these epidemiology studies as providing corroboration, but the new DPR risk assessment is predicated instead on DPR’s view that animal studies with chlorpyrifos report neurodevelopmental effects below the threshold for AChE inhibition.  The DPR risk assessment based on these animal studies uses a standard MOE of 100.  How EPA may or may not view DPR’s conclusion is not known.  In light of the August 9, 2018, decision by the U.S. Court of Appeals for the Ninth Circuit (Ninth Circuit) directing EPA to proceed with revocation of all tolerances and cancellation of all registrations for chlorpyrifos, the effect of the DPR conclusion on EPA actions is not clear.  Nevertheless, it is worth noting that, because the mechanism by which chlorpyrifos would cause such neurodevelopmental effects is unknown and is below the level that causes AChE inhibition, any presumption by EPA that other organophosphate (OP) pesticides may cause the same type of effects will likely be vigorously disputed by industry on scientific grounds.  

Please see our blog item Ninth Circuit Directs EPA to Revoke all Tolerances and Cancel All Registrations for Chlorpyrifos for more information on the Ninth Circuit’s August 9, 2018, decision.


 
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