This article was contributed by Dr. Rosalinda Volpe, Executive Director, Silver Nanotechnology Working Group (SNWG) and originally appeared on the National Nanomanufacturing Network’s InterNano website earlier today.  It is licensed under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported.

On November 3 – 6, 2009 the US Environmental Protection Agency (EPA) held a Scientific Advisory Panel (SAP) meeting in Arlington, Virginia to discuss the “Evaluation of Hazard and Exposure Associated with Nanosilver and Other Nanometal Oxide Pesticide Products.”[1] The meeting was well attended. Over seventy-five people from industry, regulatory, public interest, and academic sectors attended the meeting over three days. EPA received presentations and comments from the SAP panel members during the course of the meeting, as well as six presentations during the Public Comment period, and also received over 560 written comments which can be found on EPA’s website.

One group—The Silver Nanotechnology Working Group (SNWG)[2] —made a detailed presentation[3] to EPA supporting a fundamental regulatory consideration previously overlooked by many in attendance: nanosilver has been rationally manufactured, regulated, and used commercially for over a century with no significant adverse environmental, health, and safety effects. SNWG explained that nanosilver—often called by other names such as "colloidal silver" or "millimicron silver"—has been used in a wide range of consumer applications such as swimming pool treatments and drinking water filters with an established record under FIFRA of regulated and safe use dating as far back as the 1950’s. Thus, SNWG believes that nanosilver is not a “new” material requiring some type of special regulation and EPA needs to look beyond general conceptions of nano terminology and consider the broader established regulatory record of nanoscale silver products within the Agency. Simply put, SNWG believes that calls for treatment of nanosilver as a new material requiring development of expensive new test regimes and discriminatory regulation are difficult to justify.

Moreover, SNWG explained at the meeting that a detailed look at the history of silver within EPA shows that the toxicological studies that form the center of EPA’s existing general hazard limits for silver are derived from historical data from nanoscale silver materials and not conventional (bulk) silver as is often mistakenly assumed. For example, SNWG’s careful examination of EPA’s public registration database[4] for silver over a period of 6 decades revealed:

  • The very first registered silver product was a colloidal nanosilver algaecide product that has been safely used by millions of consumers for over 50 years (registered since 1954).
  • Every EPA silver registration between 1970 and 1990 was either a colloidal nanosilver or nanosilver-composite product.
  • The very first NON-nanosilver product registered by EPA was not registered until 1994.
  • An overall analysis reveals that today over 50% of all EPA registered silver products are in fact based on nanoscale silver.

Based on its analysis, SNWG took the formal position that EPA has a range of existing regulatory structures that have successfully addressed silver materials across the size spectrum for over 5 decades. Additionally, EPA has not any incidents of significance on the Agency’s formal incident reporting database (EPA OPP IDS) – indicating that thorough monitoring of real-life use supports the safety of these products.

The SWNG congratulated EPA for its record of successful monitoring and risk management for these materials despite different terminologies being used throughout this time period. Indeed, SNWG pointed out that with nanosilver there is perhaps more historical data and evidence of safe use than for many other regulatory materials, and the EPA has the opportunity to assess nanosilver products with confidence given this long history of safe use under existing EPA regulatons.

The SNWG is hopeful that the EPA and the other meeting attendees will examine SNWG’s position and supporting information in more detail to confirm that nanosilver has been successfully regulated for decades. If sufficient consideration is given, SNWG believes that EPA will conclude that there is no need to “fix” a regulatory process that is not “broken,” but has worked exceedingly well for decades in the case of nanosilver.


1.  EPA Scientific Advisory Panel meeting, Arlington VA (November 3 – 6, 2009).

2.  SNWG is an industry effort intended to foster the collection of data on silver nanotechnology in order to advance the science and public understanding of the beneficial uses of silver nanoparticles in a wide-range of consumer and industrial products.

3.  SNWG “Evaluation of Hazard and Exposure Associated with Nanosilver and Other Nanometal Oxide Pesticide Products”, Presentation to Scientific Advisory Panel (November 4th, 2009).

4.  NPIRS Public.