EPA Registers New Nanosilver Active Ingredient as a Materials Preservative

For Release: July 2, 2020

EPA has registered a new active ingredient that helps suppress odor causing bacteria, and algae, fungus, mold and mildew that can cause deterioration or staining in textiles. NSPW Nanosilver is registered solely for use in specified textiles including fabrics, sportswear, footwear, linens, awnings and more. The ingredient, “NSPW Nanosilver,” can be found in the pesticide product POLYGUARD-NSPW MASTER BATCH (Polyguard).

Polyguard will be formulated as a master batch, meaning that NSPW Nanosilver would be embedded within plastic beads or pellets. 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-treated textiles is below the limit of detection; the potential for environmental exposure of the polymer is presumed to be negligible.

NSPW Nanosilver was the active ingredient in a previous conditional registration, granted by EPA in 2015, for use as a materials preservative in textiles and plastics. However, that registration was challenged, and the Ninth Circuit Court of Appeals vacated it on grounds that EPA’s public interest finding for granting the registration was unsupported in the record. The current action has a modified use pattern which is expected to limit exposures, compared to the previous conditional registration. Additional data were submitted and reviewed in order to update the risk assessment for NSPW Nanosilver, which allows for an unconditional registration.

Based on EPA’s human health and ecological risk assessment, the Agency has determined  that the new active ingredient, NSPW Nanosilver, meets the regulatory standard under FIFRA for use as materials preservative in textiles in Polyguard. View the product registration and response to comments.