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July 2, 2020

EPA Registers NSPW Nanosilver as a Materials Preservative

Lynn L. Bergeson Carla N. Hutton

The U.S. Environmental Protection Agency (EPA) announced on July 2, 2020, that it registered NSPW Nanosilver as a new active ingredient that helps suppress odor-causing bacteria, and algae, fungus, mold, and mildew that can cause deterioration or staining in textiles.  EPA notes that NSPW Nanosilver is registered only for use in specified textiles, including fabrics, sportswear, footwear, linens, and awnings.  NSPW Nanosilver is the active ingredient in the pesticide product POLYGUARD-NSPW MASTER BATCH (Polyguard).  According to EPA, Polyguard will be formulated as a master batch, meaning that NSPW Nanosilver will be embedded within plastic beads or pellets.  EPA states that these beads or pellets “are polymeric materials similar to nylon or polyester which are incorporated/infused into textiles through a closed-loop manufacturing process called extrusion.”  Once introduced into the process, no beads or pellets can escape into the environment.  Available data indicate that the leach rate of nanosilver derived from NSPW Nanosilver-treated textiles is below the limit of detection; the potential for environmental exposure of the polymer is presumed to be negligible.

EPA notes that NSPW Nanosilver was the active ingredient in a previous conditional registration granted in 2015 for use as a materials preservative in textiles and plastics.  As reported in our May 31, 2017, memorandum, that registration was challenged, however, 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 unsupported in the record.  EPA states that the current action has a modified use pattern that is expected to limit exposures compared to the previous conditional registration.  According to EPA, additional data were submitted and reviewed to update the risk assessment for NSPW Nanosilver, allowing for an unconditional registration.

EPA states that based on its human health and ecological risk assessment, it has determined that the new active ingredient, NSPW Nanosilver, meets the regulatory standard under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) for use as a materials preservative in textiles in Polyguard.  Although EPA includes a link to Docket ID EPA-HQ-OPP-2020-0043 to view the product registration and response to comments, those materials are not yet posted in the docket.