By Lynn L. Bergeson and Carla N. Hutton

According to a May 9, 2022, news item published by the U.S. Environmental Protection Agency (EPA), “Advancing EPA’s Understanding of the Next Generation of Pesticides,” over the past decade, EPA “has received an increasing number of pesticide product applications that potentially contain nanomaterials.” The article notes that EPA’s current pesticide review method was not designed for nanomaterials, so each product is reviewed on a case-by-case basis. An EPA research team led by EPA scientist Dr. Chunming Su conducted an exhaustive search for patents and published literature related to nanopesticides to understand the state of the science. The item states that the team found and analyzed more than 36,000 patents and 500 peer-reviewed journal articles. The team established two general categories of nanopesticides to help inform EPA’s regulatory reviews: products with mostly metal-based nanomaterials as the active ingredient, like nanosilver and nanocopper oxide/hydroxide; and products that encapsulate and carry the active ingredient using nanomaterials (mostly carbon based) like graphene and carbon nanotubes. According to the item, the research team also developed a review framework “that includes a simple decision tree to determine what products should be classified and evaluated as a nanopesticide.” Products determined to contain nanomaterials are subject to additional assessment or data needs from the manufacturer. Dr. Andrew Byro of EPA’s Office of Pesticide Programs (OPP) states that the framework “represents a major steppingstone in the development of a method for identification of nanomaterials.” EPA will use this framework as a platform to help inform its data needs and future determinations regarding the evaluation of nanomaterials in antimicrobial pesticides.

EPA’s research team collected their findings related to the physical and chemical properties and efficacy of nanopesticides in a peer-reviewed journal article in Nature Nanotechnology, “Nano-enabled pesticides for sustainable agriculture and global food security.” According to EPA’s news item, the team “found that nano-enabled pesticides adhere better to plant surfaces and have a reduced impact on non-target organisms. Nanopesticides may also enhance plant resilience against stressors from heat or drought.” EPA states that these benefits “could lead to higher crop yield and provide more agricultural resilience to address climate change and weather extremes.” EPA notes that the research team’s findings “also highlight the data gaps and the need for additional research on potential adverse impacts of nanopesticides.”

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By Lisa M. Campbell and Lisa R. Burchi

On October 15, 2020, the U.S. Environmental Protection Agency (EPA) announced a settlement with Electrolux Home Products, Inc. (Electrolux) to resolve alleged violations of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) for importing air filter products that contain nanosilver.  Specifically, the settlement resolves EPA’s claims that Electrolux imported unregistered pesticides in violation of FIFRA Section 12(a)(1)(A) and failed to file the required Notices of Arrival in violation of FIFRA Section 12(a)(2)(N).  As part of the settlement, Electrolux will pay a civil penalty in the amount of $6,991,400.  The Consent Agreement and Final Order (CAFO) is available here.

According to EPA, Electrolux imported approximately 420,000 Frigidaire brand dehumidifiers and air conditioners that contained filters incorporating an unregistered nanosilver and that were labeled and marketed with pesticidal claims.  With regard to the incorporation of nanosilver, there currently are no nanosilver pesticide products registered with EPA for use in home appliances to disinfect the ambient air or protect the health of the user. The only nanosilver pesticides that are currently registered with EPA are approved solely for incorporation into textiles to protect those articles themselves from antimicrobial pests such as mold and bacteria that can cause deterioration, discoloration, or odors.  In those cases, the products (textiles) incorporated with nanosilver can be exempt from FIFRA registration under the “treated article” exemption.  With regard to the claims, EPA states that claims it considers pesticidal include “antibacterial filter,” and “helps eliminate bacteria in the air that can make breathing difficult.” 

Commentary

The penalty in this case is significant, and represents a potentially growing trend for penalty amounts substantially higher than past cases.  This trend is due at least in part to the inflation adjustments to statutory civil penalty amounts, as discussed further here. 

In addition to the civil penalty, the CAFO states that Electrolux has replaced the filters manufactured with nanosilver and removed the online and on-box pesticidal claims for the products it had imported, as well as some additional products already in the United States.  The CAFO states:

The SSURO also provided for the movement of subject products for the purpose of consolidating the products for a rework project whereby Respondent, among other things, would replace the filter manufactured with nanosilver contained in each unit with a filter that was not manufactured with a pesticidal substance, affix a sticker with modified language over any pesticidal claims on the product packaging, and remove all pesticidal claims made for the subject products in Respondent’s online marketing

The CAFO further states that “Respondent offered to rework all dehumidifiers and air conditioners that contained a filter manufactured with nanosilver within its possession regardless of the date those products were imported.”  To date, EPA states that Electrolux has brought over 500,000 air conditioners and dehumidifiers into compliance.

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By Lisa M. Campbell, Timothy D. Backstrom, and Carla N. Hutton

The U.S. Environmental Protection Agency (EPA) announced on July 2, 2020, that it has registered NSPW Nanosilver (a new nanosilver formulation) to suppress odor-causing bacteria and algae, fungus, mold, and mildew that can cause deterioration or staining in textiles.  Textiles that may be treated with NSPW Nanosilver include fabrics, sportswear, footwear, linens, and awnings.  NSPW Nanosilver is the active ingredient in the pesticide product POLYGUARD-NSPW MASTER BATCH (Polyguard).  The NSPW Nanosilver in Polyguard will be embedded within beads or pellets of a polymeric material in a “master batch,” and these beads of pellets will then be incorporated into treated textiles through a closed-loop manufacturing process.  EPA states that once the beads or pellets containing NSPW Nanosilver are introduced into this manufacturing process, no beads or pellets can escape into the environment.  EPA also states that the available data indicate that the leach rate of nanosilver from NSPW Nanosilver-treated textiles is below the limit of detection.

The same type of nanosilver was the active ingredient in another product that EPA previously conditionally registered under FIFRA Section 3(c)(7)(C) in 2015.  The U.S. Court of Appeals for the Ninth Circuit issued a decision vacating that conditional registration because the court concluded that the mandatory public interest finding by EPA was not adequately supported by the administrative record.  According to EPA, the new registration for NSPW Nanosilver involves a modified use pattern that will limit exposures compared to the product that received the previously vacated conditional registration.  Based on additional data that the applicant has submitted to support the use pattern as modified, EPA has prepared an updated risk assessment for NSPW Nanosilver and has determined based on that risk assessment that the product as modified meets the standard for an unconditional registration under FIFRA Section 3(c)(5).  Materials supporting this action will be posted in Docket ID EPA-HQ-OPP-2020-0043.

Commentary

Registering any new metallic silver product that satisfies the EPA criteria for classification as nanosilver for use as an antimicrobial pesticide presents special challenges, because EPA has adopted a policy that it will construe each new nanosilver product as a new pesticidal active ingredient.  The predecessor to NSPW Nanosilver (Nanosilva) was granted a conditional registration, a procedure that EPA uses when there are data gaps that must be filled before EPA is ready to make the determinations that would support issuance of an unconditional registration.  EPA may only issue a conditional registration for a product containing a new pesticidal active ingredient when EPA makes a determination that “use of the pesticide is in the public interest,” and the Ninth Circuit Court determined that EPA did not compile an administrative record adequate to support that finding.

Colloidal metallic silver products that meet the definition of nanosilver were first synthesized in the late 19th century.  Some industry stakeholders question whether the differences between different pesticide products that satisfy the EPA definition of nanosilver are sufficiently great to treat each new product as a new active ingredient, but it is also clear that the size and shape of the particles in these products do vary.  In this instance, EPA has determined that the supporting data for the application allow EPA to issue an unconditional registration.  Accordingly, the legal issue on which the Ninth Circuit based its prior decision to vacate the conditional registration for Nanosilva is not pertinent to the current registration decision.  Given the challenge to the prior registration decision, it will be important to monitor any opposition to the newly issued registration.

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By Lynn L. Bergeson and Carla N. Hutton

As reported in our February 13, 2020 blog item, the U.S. Environmental Protection Agency (EPA) announced on February 12, 2020, that it is seeking public input on a proposal to incorporate a new nanosilver pesticide product into textiles to combat odors, discoloration, and other signs of wear.  The proposed registration decision is for NSPW Nanosilver, and the proposed pesticide product, Polyguard-NSPW Master Batch (Polyguard), will be incorporated into textiles to suppress bacteria, algae, fungus, mold, and mildew, which cause odors, discoloration, stains, and deterioration.  According to EPA, based on its human health and ecological risk assessment, it has preliminarily determined that the new active ingredient in Polyguard meets the regulatory standard under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) for use as a materials preservative in textiles.  According to a February 27, 2020, memorandum placed in Docket ID EPA-HQ-OPP-2020-0043, EPA received a request to extend the comment period 30 days to allow additional time to review the documentation contained in the docket.  The memorandum states that EPA “feels that 15 additional days should be sufficient to allow for adequate review of the Proposed Decision and supporting documentation.”  Comments are now due March 30, 2020.

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By Lynn L. Bergeson and Carla N. Hutton

The U.S. Environmental Protection Agency (EPA) announced on February 12, 2020, that it is seeking public input on a proposal to incorporate a new nanosilver pesticide product into textiles to combat odors, discoloration, and other signs of wear.  The proposed registration decision is for NSPW Nanosilver, and the proposed pesticide product, Polyguard-NSPW Master Batch (Polyguard), will be incorporated into textiles to suppress bacteria, algae, fungus, mold, and mildew, which cause odors, discoloration, stains, and deterioration.  According to EPA, based on its human health and ecological risk assessment, it has preliminarily determined that the new active ingredient in Polyguard meets the regulatory standard under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) for use as a materials preservative in textiles.  EPA invites public comment on its proposal and preliminary findings.  Comments are due March 13, 2020.  More information is available in Docket ID EPA-HQ-OPP-2020-0043. 

EPA notes that NSPW Nanosilver was the active ingredient in a previous conditional registration that it granted in 2015, for use as a materials preservative in textiles and plastics.  As reported in our May 31, 2017, memorandum, that decision was challenged, and the U.S. Court of Appeals for the Ninth Circuit “vacated it on grounds that EPA’s public interest finding for granting the registration was without support in the record.”  EPA states that the currently proposed product “is solely for use in specified textiles; therefore, Polyguard will have a more limited use authorization than the previously vacated conditional registration.”  EPA notes that Polyguard will be formulated as a master batch, meaning that NSPW Nanosilver would be embedded within plastic beads or pellets, in contrast to the previous product registration, which was in the form of a liquid suspension.

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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 Lynn L. Bergeson and Carla N. Hutton

On August 26, 2019, the National Institute of Environmental Health Sciences (NIEHS) announced that the results of an NIEHS-funded study show that graphene could provide alternatives to chemicals in insect repellant and protective clothing.  The study, “Mosquito Bite Prevention through Graphene Barrier Layers,” was published in the Proceedings of the National Academy of Sciences.  According to the abstract, the researchers hypothesized that graphene films may provide mosquito bite protection for light, fiber-based fabrics.  The researchers investigated the fundamental interactions between graphene-based films and the mosquito species Aedes aegypti through a combination of live mosquito experiments, needle penetration force measurements, and mathematical modeling of mechanical puncture phenomena.  The abstract states that “the results show that graphene or graphene oxide nanosheet films in the dry state are highly effective at suppressing mosquito biting behavior on live human skin.  Surprisingly, behavioral assays indicate that the primary mechanism is not mechanical puncture resistance, but rather interference with host chemosensing.”  The researchers propose that the interference is “a molecular barrier effect that prevents Aedes from detecting skin-associated molecular attractants trapped beneath the graphene films and thus prevents the initiation of biting behavior.”  According to the abstract, placing water or human sweat on the external film surface circumvents the molecular barrier effect.  In this scenario, the abstract states, “pristine graphene films continue to protect through puncture resistance -- a mechanical barrier effect -- while graphene oxide films absorb the water and convert to mechanically soft hydrogels that become nonprotective.”

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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.”

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By Lynn L. Bergeson and Carla N. Hutton

On May 30, 2017, the U.S. Court of Appeals for the Ninth Circuit responded to two petitions for review of the U.S. Environmental Protection Agency’s (EPA) conditional registration of a nanosilver pesticide product and vacated the conditional registration.  NRDC v. EPA, No. 15-72308.  The Natural Resources Defense Council (NRDC) as well as the Center for Food Safety (CFS) and the International Center for Technology Assessment (ICTA) filed petitions in 2015 asking the court to set aside EPA’s final order granting a conditional registration for a nanosilver-containing antimicrobial pesticide product named NSPW-L30SS (NSPW).  The court vacated the conditional registration because, according to the court, “EPA failed to support its finding that NSPW is in the public interest.” 

When EPA granted the conditional registration, EPA did so on the basis that NSPW had a lower application rate and a lower mobility rate when compared to conventional-silver pesticides, and thus had the potential to reduce environmental loading and risk caused by silver release.  Petitioners disputed these facts.  While the court found that substantial evidence supports EPA’s findings that NSPW has lower application and mobility rates, the court agreed that the third premise, that current users of conventional-silver pesticides will switch to NSPW and/or that NSPW will not be incorporated into new products, “impermissibly relies on unsubstantiated assumptions.”  According to the court, EPA cites no evidence in the record to support its assumption that current users of conventional-silver pesticides will switch to NSPW (“the substitution assumption”), but contends that it will occur as a “logical matter.”  The court states that the lack of evidence supporting the substitution assumption is problematic in light of EPA’s other unsupported assumption, that there will be no new products.  The court notes that EPA assumes current users of conventional-silver pesticides will switch to NSPW because of its benefits, but that these same benefits will not prompt manufacturers to incorporate NSPW into new products.  EPA could have proved these assumptions, but without evidence in the record to support the assumptions, the court states that it “cannot find that the EPA’s public-interest finding is supported by substantial evidence as required by [the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)].”  According to the court, the public interest finding is an “essential prerequisite to conditional registration,” and EPA failed to support that finding for NSPW with substantial evidence.  The court vacated the conditional registration in whole, and did not consider the remaining issues raised by petitioners. 

More information will be available in Bergeson & Campbell, P.C.’s memorandum Appellate Court Vacates Conditional Nanosilver Registration.

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By Lynn L. Bergeson and Carla N. Hutton

On May 19, 2015, the U.S. Environmental Protection Agency (EPA) announced that it issued a conditional registration for a nanosilver-containing antimicrobial pesticide product named “NSPW-L30SS,” or “Nanosilva.”  This is the second nanosilver registration issued by EPA and reflects the Agency’s growing expertise in addressing, processing, and approving nanopesticide registration applications.  According to EPA, the product will be used as a non-food-contact preservative to protect plastics and textiles from odor- and stain-causing bacteria, fungi, mold, and mildew.  Items to be treated include household items, electronics, sports gear, hospital equipment, bathroom fixtures, and accessories. EPA based its decision “on its evaluation of the hazard of nanosilver after reviewing exposure data and other information on nanosilver from the applicant, as well as data from the scientific literature.”  EPA states that these data show that treated plastics and textiles release “exceedingly small amounts of silver.”  Based on this evaluation, EPA “determined that NSPW-L30SS will not cause unreasonable adverse effects on people, including children, or the environment and that it would be beneficial because it will introduce less silver into the environment than competing products.”  EPA notes that it is requiring the company “to generate additional data to refine the Agency’s exposure estimates.”  According to EPA, it will post a response to comments received on its 2013 proposed registration decision document, as well as the current decision document, in the rulemaking docket.

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