Reclassifying Nanosilver

Silver—claimed to be nanoparticles—employed to kill bacteria in washing machines will now be regulated as a pesticide, EPA announced late last month. Currently, washers that generate silver ions are classified as devices and are not required to be registered with EPA.

The products at issue are Samsung washing machines that are advertised as using silver ions to kill 99.9% of odor-causing bacteria. This technology, called SilverCare, generates ions by applying current to two silver plates housed next to the machine's tub. The ions are then directed into the tub during the wash cycle.

"EPA has determined that the Samsung silver ion-generating washing machine is subject to registration requirements under the Federal Insecticide, Fungicide & Rodenticide Act," according to an EPA statement. The agency decided to change the classification of the washer because it releases silver ions into the laundry "for the purpose of killing microbial pests," the statement explains.

For its part, Samsung has pledged to comply with the change of policy. "Samsung has and will continue to work with EPA and state regulators regarding regulation of the silver washing machine," the company says.

Several groups concerned about the environmental impact of nanoparticles of silver had asked EPA to reevaluate the way products containing such materials are regulated. For example, environmental group Natural Resources Defense Council (NRDC) noted in a letter to EPA that there are currently more than 40 products on the market in addition to Samsung's washing machine that have made or implied claims of using nanoparticles of silver to kill bacteria.

NRDC praised EPA for taking what it called a "step in the right direction" by reclassifying nanosilver generated in a washer as a pesticide. The group also said this revised policy should lead to EPA reassessing other products that use nanoparticles of silver for their biocidal qualities.