On July 6, 2012, the U.S. Environmental Protection Agency (EPA) announced the establishment of a registration review docket for nanosilver. EPA states that registration review is its “periodic review of pesticide registrations to ensure that each pesticide continues to satisfy the statutory standard for registration, that is, the pesticide can perform its intended function without unreasonable adverse effects on human health or the environment.” Registration review dockets include information intended to assist the public in understanding the types of information and issues that EPA may consider during the course of registration reviews. According to the preliminary work plan, EPA has information that there are silver-based pesticide products that were registered without the registrant disclosing to EPA the presence or characteristics of the nanosilver in their products. EPA sent a letter in August 2009 to each registrant with silver-based products requesting a statement as to whether their products contained any amount of silver in any form having a dimension that measures between 1 and approximately 100 nanometers. Four registrants responded that their products, which were registered using data for conventional silver, contain nanosilver. In the preliminary work plan, EPA states it is identifying several other products, registered using data for silver chloride, as potentially containing nanosilver. The registration review for nanosilver includes these products, as well as the two HeiQ nanosilver products conditionally registered in December 2011. According to the preliminary work plan, EPA believes that additional data are needed to determine whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) standard for maintaining these registrations is met “due to nanosilver’s unique physical and chemical properties, and thus nanosilver’s potentially different health and safety properties as compared to silver.”

With the exception of the HeiQ products, EPA does not have information on the composition of the nanosilver or potential nanosilver in the selected products, and is proposing that the first phase of data submission be focused on determining the characteristics of the silver present in these products. According to EPA, if nanosilver is identified during the first phase of data submission, then the next phase of proposed data submission would be determining the form and concentration of silver released from the products identified to contain nanosilver. If nanosilver is found to be released, then the final phases of data submission will concern health effects, ecological effects, and environmental fate. Comments are due August 19, 2012.

EPA notes that, on February 29, 2012, it sent data call-in notices (DCI) to registrants with products included in the silver and compounds registration review case requesting information on particle size. EPA is currently reviewing responses to the DCIs and “may determine that some of the products covered by that case and DCI should also be included in this Nanosilver Registration Review case.” If EPA determines that any of these silver and compounds products need to be included in the nanosilver registration review case, it will include a statement in the docket, and reflect that determination in the final work plan for nanosilver. EPA’s anticipated schedule is below:


Estimated Month/Year

Phase 1: Opening the docket

Open Public Comment Period for Docket

June 2012

Close Public Comment Period for Docket

August 2012

Phase 2: Case Development

Develop Final Work Plan (FWP)

August 2012

Issue DCI

August 2012

DCI 90-day responses due1

November 2012

Data Submission – All data2

August 2015

Open Public Comment Period for Preliminary Risk Assessments

January 2016

Close Public Comment Period

February 2016

Phase 3: Registration Review Decision

Open Public Comment Period for Proposed Reg. Review Decision

September 2016

Close Public Comment Period for Proposed Reg. Review Decision

November 2016

Final Decision and Begin Post-Decision Follow-up

March 2017

Total (years)


1 — The 90‐day responses will be due based on the date the affected registrant receives the DCI that EPA anticipates issuing.

2 — This date reflects the last date on which required data are due, based on the schedule expected to be included in the anticipated DCI.  Earlier deadlines for submission will be included in the DCI for various data requirements due earlier.