On May 30, 2017, the Ninth Circuit Court of Appeals vacated EPA’s conditional approval of Nanosilva NSPW-L30SWS, a type of antimicrobial silver registered as a materials preservative for textiles and plastics. NRDC v. United States EPA, 2017 U.S. App. LEXIS 9360 (9th Cir. 2017). The active ingredient in the product is nanoscale silver. The National Resources Defense Council (NRDC), Center for Food Safety (CFS), and the International Center for Technology Assessment (ICTA), appealed the conditional approval. The Ninth Circuit found that EPA had not sufficiently supported its finding that early approval was in the public interest – a requirement for conditional approval under the Federal Insecticide, Fungicide, Rodenticide Act (FIFRA). EPA granted conditional approval of the product in May 2015.
Under FIFRA, EPA is permitted to issue conditional registration for a pesticide containing an active ingredient not contained in any currently registered pesticide, only where: 1) use of that pesticide will not cause any unreasonable adverse effect on the environment, and 2) use of the pesticide is in the public interest. 7 U.S.C. § 136a(c)(7)(C). The Ninth Circuit explained that the Agency considers this type of conditional registration when it has not received sufficient data to determine that long-term use of a pesticide is reasonable. Id. In its decision to grant conditional approval of NSPW, EPA found that use of the pesticide is in the public interest because it has the “potential” to reduce the amount of silver released into the environment.
NRDC, CFS, and ICTA disputed the factual premises underlying the EPA’s public-interest finding. Petitioners challenged the Agency’s findings that:
- NSPW has a lower application rate (e., it uses less silver) than conventional-silver pesticides;
- NSPW has a lower mobility rate (e., it is less likely to release silver into the environment in detectable quantities); and
- Current users of conventional-silver pesticides will switch to NSPW and/or that NSPW will not be incorporated into new products (i.e., registration of NSPW will reduce the amount of silver pesticides used).
While the Ninth Circuit found that EPA’s analysis supported finding both lower application rate and lower mobility rate, it also found that the Agency “impermissibly relie[d] on unsubstantiated assumptions” to support the finding that the conditional registration of NSPW will reduce the amount of silver pesticides used. EPA had concluded that use of NSPW is in the public interest because it has the “potential” to reduce the amount of silver released into the environment. The Ninth Circuit held that EPA’s conclusion requires two interrelated and unstated assumptions. The Ninth Circuit found that
- EPA assumed that current users of conventional-silver pesticides will replace those pesticides with NSPW (“the substitution assumption”); and
- EPA assumed that NSPW will not be incorporated into new products to the extent that such incorporation would actually increase the amount of silver released into the environment (“the no-new-products assumption”).
The Ninth Circuit held that neither assumptions are supported by substantial evidence. In fact, the Ninth Circuit found that if the EPA’s substitution and no-new-products assumptions are incorrect, NSPW may actually increase the amount of silver released into the environment, which would contravene the identified public interest. The Ninth Circuit explained that
EPA may not satisfy the [substantial evidence] requirement by simply finding that a pesticide has the “potential” to be in the public interest—especially where the pesticide also has the “potential” to contravene the public interest. Accordingly, where an essential premise of a public-interest finding is only supported by bare assumptions, as in the present case, we will find substantial evidence lacking.
NRDC v. United States EPA, 2017 U.S. App. LEXIS 9360 (9th Cir. 2017).
 The Ninth Circuit held EPA to the substantial evidence standard as dictated by FIFRA. 7 U.S.C. § 136n(b). The Court explained that “[s]ubstantial evidence means more than a mere scintilla but less than a preponderance; it is such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” Nat. Res. Def. Council v. EPA (NRDC), 735 F.3d 873, 877 (9th Cir. 2013).