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.

• Email This
• Print
• Comments

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

On February 6, 2020, Corteva Agriscience (Corteva), announced it will discontinue all production of the organophosphate (OP) insecticide chlorpyrifos by the end of the year.  Corteva and its corporate predecessor, Dow AgroSciences, have been the principal global manufacturers of chlorpyrifos.  Corteva announced that its decision to stop selling chlorpyrifos was based entirely on financial considerations.  This announcement came on the same day that Corteva had previously agreed it would end further sales of chlorpyrifos in California, and less than a week after the date the European Union (EU) ended all sales of chlorpyrifos in member states.  These actions followed a number of prior actions taken by other national and state governments to ban or severely restrict chlorpyrifos.  Corteva emphasized in its public statements that the science demonstrates that chlorpyrifos can be safely used, but that the company made a business decision based on the declining markets for the product.  In an interview reported by the Washington Post, Susanne Wasson, Corteva's President for Crop Protection said, “It’s a tough decision for us to make, but we don’t feel like it’s viable going forward.” In other statements, Corteva noted that in the last ten years their share of the global chlorpyrifos market had declined from 75% to less than 20%.

Chlorpyrifos has been registered for use in the U.S. for over 50 years, but has become increasingly controversial in the dozen years since the Pesticide Action Network of North America and the Natural Resources Defense Council filed a petition in 2007 to cancel all registrations and revoke all tolerances for chlorpyrifos.  Following a protracted court battle and a decision by the Ninth Circuit Court of Appeals to force the U.S. Environmental Protection Agency (EPA) to take final administrative action concerning the 2007 petition, EPA proposed near the end of the Obama Administration to revoke all existing tolerances for chlorpyrifos.  A significant basis for this proposal was a controversial decision by a panel of EPA scientists that the default tenfold safety factor established by the Food Quality Protection Act (FQPA) for infants and children, which EPA had previously waived based on studies establishing a threshold for acetylcholinesterase (AChE) inhibition, should be reinstated.

The new EPA safety factor determination was based in large measure on epidemiology studies that reported an association between exposure to chlorpyrifos at levels below the presumed threshold for AChE inhibition and adverse neurodevelopmental effects in children.  Many industry scientists disputed the scientific basis for this EPA determination because confounding exposures and methodological biases in the epidemiology studies may have influenced the reported association with neurodevelopmental effects and because the EPA determination made unprecedented use of epidemiology data.  Beyond the effect on chlorpyrifos, the EPA decision will likely continue to be controversial because EPA included a similar safety factor determination for all OP pesticides, even though the mechanism responsible for the reported neurodevelopmental effects attributed to chlorpyrifos has not been identified and the other OP products were not studied in the epidemiology studies.

In the first year of the Trump Administration, EPA Administrator Scott Pruitt decided not to adopt EPA’s previously proposed tolerance revocation and instead to deny formally the 2007 petition, citing unresolved scientific issues.  This reversal of course, however, was not accompanied by any new scientific assessment or by any explicit revision of the prior FQPA safety factor determination.  Later, the California Department of Pesticide Regulation (DPR) decided to designate chlorpyrifos as a Toxic Air Contaminant, a decision that was noteworthy because it was based primarily on new toxicology studies that DPR stated reported neurodevelopmental effects well below the threshold for AChE inhibition.  DPR deemphasized the epidemiology data relied on in the EPA safety factor determination in its decision.  Although EPA later stated that it would address these new toxicology studies as part of an accelerated registration review process, there were intervening decisions by the EU and by California to ban new sales, which may have contributed to Corteva’s February 6, 2020, decision to cease chlorpyrifos production.

Commentary

The decision by Corteva to cease manufacturing chlorpyrifos reminds us that the decision to continue marketing any chemical substance cannot be based solely on the scientific data, but must also consider the regulatory climate and the economic viability of the product.  For those of us with a long memory, the decision by Corteva is reminiscent of the decision nearly 40 years ago by the Dow Chemical Company to pull the plug on 2,4,5-T and silvex, after Dow had expended millions of dollars and many years of effort to contest an emergency suspension and subsequent cancellation of these herbicides.  Dow made this decision even though it believed that the available data demonstrated the safety of those products.

• Email This
• Print
• Comments

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.

• Email This
• Print
• Comments

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

On May 22, 2015, the European Food Safety Authority (EFSA) issued a call for new scientific information relevant to the evaluation of the risk to bees in the European Union (EU) from the use of the three neonicotinoid pesticide active substances:  clothianidin, imidacloprid, and thiamethoxam (the substances).

The call for data complies with the decision taken by the European Commission in May 2013, Commission Implementing Regulation (EU) No. 485/2013, to put in place measures to restrict the use of the substances, which at the time included prohibiting use of the active substances clothianidin, thiamethoxam, and imidacloprid as a seed or soil treatment and for pre-flowering applications on crops attractive to bees and for cereals other than winter cereals.  In May 2013, the Commission also stated that within two years it would initiate a review of any new scientific information. 

EFSA is urging national authorities, research institutions, industry, and other interested parties to submit all information on the effects, exposure, and risks of the three substances regarding bees -- honeybees, bumble bees, and solitary bees -- when used as seed treatments and granules.  This can include:

• Literature data, including grey literature and any other data from research activities relevant to the risk assessment for bees for the uses of the three substances applied as seed treatments and granules.  Data that have been provided and identified as relevant by EFSA in its published systematic literature review report need not be submitted, however.
• Study reports conducted specifically to assess the risk to bees from the three substances applied as seed treatments and granules, and not yet considered under the previous EFSA assessments (EFSA Journal 2013;11(1):  3066, 3067, 3068).
• National evaluations and/or monitoring data relevant to the risk assessment for bees for the uses of the three substances applied as seed treatments and granules that are available at the Competent Authorities of Member States and not yet considered under the previous EFSA assessments, listed in the above bullet.
• Data that EFSA stated were not relevant in its published systematic literature review report may be submitted only if accompanied with a scientific rationale supporting their relevance.

The notice states that all information should be submitted by September 30, 2015.  Any information submitted can be claimed as confidential by following procedures set forth in Article 63 of Regulation (EC) No 1107/2009.  EFSA will review the material provided from this call for data and offer conclusions concerning an updated risk assessment following receipt of a follow-up mandate from the European Commission.

• Email This
• Print
• Comments