NRDC v. EPA: The Ninth Circuit issues a narrow ruling on EPA’s conditional registration of a “nano-pesticide”

Vol. 45 No. 5

Michael T. Novak is a partner and co-chair of the Pesticide Practice Group at Keller and Heckman LLP. Eric P. Gotting is a partner and serves in the Litigation and Environmental Practice Groups at Keller and Heckman LLP. Kathryn M. Biszko is an associate in the Environmental Practice Group at Keller and Heckman LLP.

The U.S. Environmental Protection Agency’s (EPA) first-ever conditional registration of a nanosilver pesticide was recently challenged on multiple fronts. Natural Res. Def. Council v. EPA, 735 F.3d 873 (9th Cir. 2013) (NRDC v. EPA). The Natural Resources Defense Council (NRDC) not only questioned EPA’s approach to granting “conditional” pesticide registrations, but also the very safety of nanosilver itself. The U.S. Court of Appeals for the Ninth Circuit, however, largely rejected NRDC’s suit. On November 7, 2013, the court upheld EPA’s conditional registration with one narrow exception and remanded the registration decision back to EPA on that issue. EPA, working with the pesticide registrant, subsequently amended the pesticide label to address the grounds for remand, thereby permitting the conditional registration to stand.

While NRDC v. EPA confirms the lawfulness of EPA’s current approach for conditionally registering nano-sized pesticides, these products will continue to draw interest, and possibly challenge, from public interest groups.

EPA’s statutory authority under FIFRA to issue conditional pesticide registrations

At issue in this case was EPA’s conditional registration of two similar products, AGS-20 and AGS-20 U (collectively, “AGS-20”), under the federal pesticide law, the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). The AGS-20 product, registered by the product manufacturer, HeiQ Materials (HeiQ), uses nanosilver to control bacteria and mold in textiles such as sports clothing, blankets, and carpet. The product contains extremely small “nanosilver” particles measuring between one and one-hundred nanometers in diameter. For perspective, a human hair is approximately 80,000–100,000 nanometers in width.

Under FIFRA, EPA is charged with the registration of any pesticide product sold or distributed in the United States. To register a pesticide, an applicant must submit scientific data demonstrating the product will not present unreasonable adverse effects to man or the environment. Data required to register vary, depending on the chemistry of the product and its claimed use patterns.

Section 3(c)(7) of FIFRA gives EPA authority to grant a “conditional” registration, where some necessary data have not been provided by the registrant in its application. To do so, EPA must determine that use of the pesticide will not “significantly increase the risk of unreasonable adverse effects on the environment.” EPA has generally granted conditional registrations for products similar to other products already registered, as well as new uses of currently registered products. EPA has discretionary authority, however, to grant conditional registration to a new active ingredient where (1) required data are lacking because a data requirement was imposed so recently that the registrant did not have adequate time to generate the data, (2) the pesticide will not cause unreasonable adverse effects on the environment while data are being generated, and (3) registration is in the public interest. Typically, EPA grants registrants one to four years to generate and submit the additional data.

EPA’s conditional registration of HeiQ’s products

On December 1, 2011, EPA used its discretionary authority under FIFRA section 3(c)(7) to grant conditional registration to HeiQ for AGS-20, setting forth a two-tiered approach for additional testing of the product over four years. Decision Document: Conditional Registration of HeiQ AGS-20 as a Materials Preservative in Textiles, EPA-HQ-OPP-2009-1012-0064 (Dec. 1, 2011).

During the registration process, EPA’s FIFRA Scientific Advisory Panel (SAP) determined that nano-scale pesticides may have different properties and effects than larger molecules of the same substance and that there was limited scientific data regarding the toxicity and exposure levels of nanosilver particles. As a result, although EPA had previously registered silver, EPA requested that HeiQ classify AGS-20 as “new” active ingredient pesticide because of its small silver particles.

In granting the conditional registration, EPA considered AGS-20’s two uses (nanosilver coated on textiles and incorporated into the fibers themselves) as well as three routes of exposure to humans for each use (oral, dermal, and aggregate). EPA assessed the risks that the pesticide might pose to workers, consumers, and the environment. EPA’s consumer assessment used a three-year old child (a toddler) as the most vulnerable subpopulation and examined a hypothetical toddler’s potential exposure to AGS-20. The three-year old was assumed to be exposed to the substance by both wearing and mouthing (i.e., chewing or sucking on) clothing or another item treated with AGS-20. EPA concluded that the aggregate exposure measure did not indicate that AGS-20 posed an unreasonable risk to consumers or the environment.

EPA granted conditional registration, subject to further investigation during the first four years of its sale and distribution. Specifically, EPA required HeiQ to perform route-specific toxicity tests for various exposures, as well as product characterization and stability studies, to determine if nanosilver would break away from AGS-20 or textiles treated with the pesticide. If nanosilver was found to break away, EPA would require HeiQ to conduct additional tests to determine the pesticide’s impact on humans and the environment.

NRDC files suit challenging EPA’s HeiQ decision

NRDC challenged the conditional registration in court, arguing that EPA erred in determining that use of AGS-20 would not cause any unreasonable adverse effect on man and the environment while HeiQ collected the required data during the conditional registration period.

NRDC asked the Ninth Circuit to set aside the conditional registration, arguing that EPA failed to (1) consider risks posed by the antimicrobial to infants and babies, and (2) account for aggregate exposures to the consuming public from other nanosilver-based products. NRDC claimed that infants and babies represent a vulnerable subpopulation due to low body weight and would have potentially high exposures to AGS-20 through mouthing activity on treated fabrics. NRDC added that the agency’s risk assessment would have raised significant concerns if it had considered exposures to younger children. With regard to aggregate exposures, NRDC argued that consumers of all ages would not only be exposed to AGS-20, but also nanosilver in other commercial products not registered by EPA, such as cosmetics or cleaning products. Although EPA acknowledged these additional exposures in its risk assessment, NRDC claimed that the agency did not take them into account when assessing the overall health risks of AGS-20 and that EPA incorrectly concluded there would be no unreasonable adverse effects during the conditional registration period.

The court’s decision

After concluding that NRDC had standing, the Ninth Circuit’s decision granted in part, and denied in part, NRDC’s petition to vacate the conditional registration. In addition to addressing the two issues raised by NRDC, the court raised a third issue, sua sponte, as to whether EPA properly applied its risk-assessment policy approving AGS-20 for the surface coating of textiles. 735 F.3d at 881. It is this third issue that led to the remand of the registration to EPA.

The court looked specifically to EPA’s risk assessment using the concept of a margin of exposure (MOE). EPA sets an MOE by assessing hypothetical and actual exposure scenarios, as well as toxicological data on a pesticide, and then applies it to determine whether exposure to a pesticide might cause an adverse effect to a human.

In HeiQ’s case, EPA’s risk assessment stated there is a risk concern requiring mitigation if the MOE is less than or equal to 1,000. EPA found that the aggregate MOE for a surface-coated textile was equal to 1,000 but concluded that there was no risk concern. In essence, the risk assessment resulted in calculations that were right on the line between showing a “concern” and “no concern.” The Ninth Circuit concluded that EPA failed to follow its own rules and policy, which required a risk concern determination when MOE calculations are equal to 1,000. 735 F.3d at 884.

Of note, the court’s decision was not based on the conclusion that nanosilver generally poses a risk to health or the environment, as the court did not evaluate studies or other information on whether nanosilver poses a risk or not. Instead, the court limited its decision to considering EPA’s own internal policy interpreting risk assessment data. 

The court rejected NRDC’s two principle arguments. First, as to whether EPA should have based its risk assessment using exposures to infants rather than toddlers, the court found that EPA’s use of toddlers was reasonable. In particular, EPA’s approach was consistent with similar risk assessments and, given toddler’s aggressive mouthing of clothing and blankets, representative of an actual exposure scenario. 735 F.3d at 881. Second, the court ruled that substantial evidence supported EPA’s decision not to account for aggregate exposure to other nanosilver products, as FIFRA does not require this assessment for pesticides like AGS-20. Moreover, the court agreed with EPA’s determination that no data were available to assess exposure to other nanosilver products. 735 F.3d at 885.

While NRDC obtained a partial victory vis-à-vis HeiQ, the decision also represents a defeat for the group on significant arguments aimed at restricting the nanotechnology and pesticide industry as a whole. Ultimately, nothing in this opinion casts doubt on EPA’s conditional registration process. The court rejected NRDC’s arguments regarding consideration of aggregate exposures and exposures to infants. The court never questioned the overall safety of nanosilver and instead noted that EPA’s risk assessment, even for surface coatings, does not mean that consumers are actually at risk from nanosilver materials.

The future of nanotechnology and pesticides

The aftermath of NRDC v. EPA is encouraging for EPA and its current approach in regulating the nanotechnology industry. With respect to AGS-20, on December 17, 2013, EPA approved an amendment to the product label limiting the application rate to 19 ppm (by weight) of silver for surface coatings and the types of fibers that may be treated. Approval of Label Amendment for HEIQ AGS-20 (EPA Reg. No. 85249-1). This change addressed the Ninth Circuit’s concerns about the aggregate MOE. HeiQ is now able to lawfully sell AGS-20.

Public interest groups, however, remain concerned about the risks posed by nano-sized products and continue to challenge EPA’s risk assessments for nanotech products.

On August 27, 2013, EPA announced a proposed decision to register a new product, “Nanosilva,” as a preservative to protect plastics and textiles from odor and stain-causing bacteria, fungi, mold, and mildew. Draft Decision Document: Proposed Conditional Registration of Nanosilva as a Materials Preservative in Plastics, EPA-HQ-OPP-2012-0594-0002 (Aug. 27, 2013). In light of the ongoing HeiQ litigation at that time, EPA broadened its supporting risk assessment to include exposure to children in age ranges of 6–12 months, 1–2 years, and 2–3 years.

Despite the use of a broader age range, both NRDC and the Center for Food Safety filed comments on EPA’s Draft Decision Document for Nanosilva, alleging that EPA declared a “low probability” of adverse risk during the conditional registration while FIFRA requires EPA to determine that the pesticide will not cause “any” unreasonable adverse effect. It remains unclear whether EPA will move forward with the registration, and, if it does, whether these groups will challenge EPA’s approval.


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