Does the Nanosilver Dispute have a Silver Lining?

By: Rachel Shelton, Staff Member

The National Resources Defense Council (NRDC) is dueling with the EPA over the agency's approval of nanosilver for use in fabrics.[1] NRDC's brief, filed last year in the 9th Circuit, alleges that the EPA allowed the substance on the market without reviewing legally-required information on its potentially harmful effects.[2]

So what is nanosilver and what's the big deal? According to a report prepared for the EPA, nanosilver refers to the nano-particulate form of silver, which is used as a biocide to kill microbes in a variety of consumer products, from medical devices to food supplements to textiles.[3] The EPA report recognizes the need for a comprehensive risk assessment of the effects that nanosilver might have on the health of humans and the environment.[4] The need for an assessment is becoming increasingly important as human exposure to nanosilver becomes more and more common. Clothing treated with nanosilver, such an antimicrobial socks which are designed to decrease foot odor, is now available on the market.[5] The verdict is out on whether the additive is safe - researchers do not understand how nanosilver, toxic to bacteria and other microbes, affects humans.[6]

Despite the lack of a scientific consensus on nanosilver, in 2010 the EPA "conditionally registered" nanosilver and allowed its use for four years, subject to the requirement of additional environmental and toxicology data from manufacturers.[7] Nanosilver is classified as a "pesticide," and as such falls under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).[8] Under the FIFRA regulation scheme, a pesticide may be registered "conditionally" for such period reasonably sufficient to generate enough data to make a decision about whether or not it is harmful.[9] Registration is contingent on an EPA finding that the pesticide will not cause an "unreasonably adverse effect on the environment" during the interim period and that the use of the pesticide is in the "public interest."[10]

The NRDC claims that the EPA should be more discriminating with respect to conditional registration and accuses the agency of abusing the loophole by allowing companies to market a chemical before key data was presented on its toxicity to humans and the environment.[11] The EPA's initial analysis of the risks, NRDC argues, failed to evaluate the potential harm to infants who are exposed to nanosilver and was not supported by substantial evidence; the finding of no "unreasonably adverse effect" was therefore improper.[12]

With such a broad loophole at issue, it seems doubtful that the EPA will fail to justify the terms of their conditional approval. NRDC may have a point though - is it really in the "public interest" to put pesticides in our socks? Regardless of the outcome of the case, controversy over the use and regulation of new nanotechnology is likely here to stay.
[1] Lawsuit Seeks to Block EPA's 'Free Pass' on NanosilverNatural Res. Def. Council (Jan. 26, 2012),
[2] Id.
[3] State of the Science Literature Review: Everything Nanosilver and MoreEPA xii (2010), available at
[4] Id. at xiv.
[5] See, e.g., Magical Socks Nanosilver with Silver NanoparticlesNanoTrade, (last visited Apr. 7, 2013).
[6] Naomi Lubick, Nanosilver Tracked in RatsChemical & Engineering News (Aug. 17, 2012),
[7] Pesticide News Story: EPA Proposes Conditional Registration of Nanosilver Pesticide ProductEPA (Aug. 13, 2010),
[8] State of the Science Literature Review: Everything Nanosilver and More, supra note 3, at 12-13.
[9] 7 U.S.C. § 136(c)(7)(C) (2012).
[10] Id.
[11] Mae Wu, Nanosilver StinksSwitchboard: Natural Res. Def. Council Staff Blog (Sept. 15, 2010),
[12] Lynn L. Bergeson, Recent Developments in NRDC's Case Concerning EPA's Conditional Registration of NanosilverNano and Other Emerging Chem. Techs. Blog (June 23, 2012),