Comments on EPA's Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray

National Center for Environmental Assessment
Office of Research and Development
Environmental Protection Agency
1200 Pennsylvania Ave. NW
Washington DC  20460-0001

Subject:  Comments on “Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray,” EPA Document EPA/600/R-10/081, EPA National Center for Environmental Assessment, Office of Research and Development. 

Docket ID: EPA-HQ-ORD-2010-0658

Environmental Working Group (EWG), a non-profit public health research and advocacy organization, submits these comments regarding the Environmental Protection Agency’s (EPA) draft report titled “Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray.”

EPA’s draft report summarizes the publicly available data regarding the potential health and environmental impacts of nanoscale silver (nanosilver), as well as what is known about the range of consumer products that incorporate this increasingly popular antimicrobial pesticide.

Given the enormous gaps in basic market, health and safety information that EPA itself identified, EWG questions EPA’s earlier decisions to approve nanoscale, silver-based antimicrobials for use in consumer products and calls on the agency to conduct thorough health and safety evaluations of novel nanoscale materials prior to market entry.

As EPA notes in its report, various nanomaterials, especially nanosilver formulations, are likely used in a variety of consumer products found in the homes, schools and offices of many Americans. These include athletic clothing, stuffed animals, pillows, toothpaste, cutlery, cutting boards and more.  Yet significant questions remain about nanomaterials’ long-term health effects, and EPA has acknowledged that the limited data currently available are insufficient to establish whether such products are safe.

EPA published its draft case study on engineered nanoscale silver in disinfectant sprays in August 2010. The case study did not present specific conclusions regarding possible ecological or health risks (EPA 2010a); instead, EPA requested public comments in order to identify scientific gaps that hinder environmental health and safety assessments of nanosilver and to help the agency prioritize long-term research efforts in the area.

EWG agrees with EPA that there is a lack of basic health and safety information on nanosilver.  The lack of information makes it impossible to complete a meaningful risk assessment and to understand the potential environmental and health consequences of its widespread use. To date, EPA has not required manufacturers to conduct testing that would fill these data gaps prior to marketing their nanosilver products. The case study highlights the large number of data gaps and unknowns that EPA and nanosilver manufacturers must address, including:

  • The lack of a reliable estimate of domestic and worldwide production of nanosilver products (chap. 3 p. 11);
  • The lack of information about the primary sources of nanosilver exposure in daily life and in the workplace (chap. 5 p.59);
  • Gaps in the understanding of the relationship between nanoparticles’ physical properties (size, shape etc.) and their toxicity to humans and the environment (chap. 6 p. 58);
  • The lack of information on the persistence of manufactured nanosilver particles in the environment (chap. 4 p. 23);
  • The lack of information on how nanosilver particles behave after production, including their stability in consumer products; release during disposal, washing or other use; effects on wastewater treatment processes; and effects on receiving water bodies (chap. 3 p. 11);
  • The insufficient knowledge about various types of silver materials, such as engineered nanosilver particles and colloidal silver, and their behavior in the environment (chap. 4 p.23);
  • The absence of monitoring programs and the resulting lack of information on background levels of silver particles in the environment, especially in water bodies (chap. 2 p. 24);
  • The unknown potential for health effects from environmental exposure to secondary sources, such as nanosilver-contaminated water supplies or nanosilver-loaded sewage sludge (chap. 6 p.58).

Despite these data gaps, EPA has registered and sanctioned the marketing of many nanosilver materials, according to the research by the Wilson Center Project on Emerging Nanotechnologies, a not-for-profit research center, and advertisements on company websites (Project on Emerging Nanotechnologies 2009; American Biotech Labs 2010).

In EWG’s recent comments to EPA on the use of nanosilver in textiles (EWG 2010), we advised EPA to require manufacturers of all novel nanomaterials to submit sufficient information to assess their safety prior to market entry. The case study presented by EPA’s Office of Research and Development on nanosilver in disinfectant sprays heightens our concern over the potential for adverse consequences from nanosilver releases into the environment. Consequently, EWG urges EPA to:

  • Catalog and make public production, use and release information on nanosilver across all registered products;
  • Ensure that a risk assessment includes cumulative exposures of the most sensitive populations to all nanosilver-based products;
  • Outline how research needs and data gaps will be met, from both technical and regulatory perspectives;
  • Establish a system to ensure environmental and biological monitoring of nanomaterials;
  • Assess background levels of naturally occurring as well as current levels of engineered nanoparticles.

We also noted that EPA’s case study offers peculiar disclaimers about EPA’s lack of knowledge as to whether “any exposure actually occurs to such a product” (EPA 2010a).  EPA provided no original information on registered pesticides that contain or may contain nanosilver but instead relied on a database published by the Wilson Center Project on Emerging Nanotechnologies to highlight eight companies that report the use of nanosilver in disinfectant sprays. EWG urges EPA to conduct its own comprehensive assessment of nanosilver products, manufacturing locations and production estimates, and to share this information with the public.

The EPA case study on nanosilver in disinfectant spray underscores the inadequate resources currently dedicated to environmental health and safety studies of novel materials. New nanomaterials and products are being introduced into the marketplace and the environment before anyone has assessed their risks or even established methods for characterizing the risks, largely due to the limitations of the Toxic Substances Control Act.

EPA has developed a suite of tools for screening and assessing new chemicals in an effort to flag chemicals of concern during the registration process (EPA 2010b). However, these tools are ineffective and insufficient to address the toxicity of inorganic materials in general and of engineered nanoparticles such as nanosilver in particular (EPA 2010b).

In addition to the recommendations above, EWG strongly urges EPA to use its existing authority to complete the announced Significant New Use Rule (SNUR), Information Gathering Rule and Test Rule that would require manufacturers of all engineered nanomaterials to register and to provide characterization and toxicity information. Within the limitations of TSCA this set of rules would ensure transparency and provide critical data as EPA begins to access the impacts to public health from engineered nanomaterials.


David Q. Andrews, PhD, Senior Scientist
Olga V. Naidenko, PhD, Senior Scientist
Jane Houlihan, MSCE, Senior Vice-President for Research

Environmental Working Group
1436 U. Street, Suite 100, NW
Washington DC 20009


American Biotech Labs. 2010.  About the Company.  Accessed: 9/27/2010.  Available:

EPA (Environmental Protection Agency). 2010a.  Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. EPA Document Docket EPA-HQ-ORD-2010-0658. Available:

EPA (Environmental Protection Agency). 2010b.  Sustainable Futures: Models and Methods.  Pollution Prevention & Toxics.  Accessed: 9/24/2010. Available:

EWG (Environmental Working Group). 2010. Comments on Registration of "HeiQ AGS-20," a new nanosilver active ingredient intended for use as a preservative in textile products.  Docket ID: EPA-HQ-OPP-2009-1012

PEN (Project on Emerging Nanotechnologies). 2009. Inventory of nanotechnology-based consumer products. Produced in partnership between the Woodrow Wilson International Center for Scholars and the Pew Charitable Trust. Accessed: September 26, 2010.  Available:

Disqus Comments

Related News

Continue Reading