EPA to Regulate Nanoproducts Sold As Germ-Killing

Advocates of tougher regulation oppose that approach.

"Its sounds like a major legal loophole and is probably something that will have to be dealt with in the courts," said Mae Wu, a lawyer at the Natural Resources Defense Council, which has been pushing the EPA to regulate nanosilver.

Efforts to reach an official at the Sharper Image were unsuccessful.

Conventional materials, such as carbon or gold, exhibit unconventional properties when manufactured on a nanoscale. That is largely because the tiny particles have relatively large surface areas for their small mass, which makes them very chemically reactive.

Carbon, for example, does not conduct electricity well in its bulk form but does so very well when spun into fibers a few nanometers in diameter. And though bulk gold hardly reacts with substances around it, nanoparticles of gold can burn up bacteria and other living cells.

Silver can kill microbes even in bulk form but is more efficient as nanoparticles. Nanosilver also can be easily incorporated into a variety of products, such as food containers and shoe liners. That characteristic has made it the most common type of nanomaterial marketed to consumers, according to a database of about 350 nanoproducts maintained by the Project on Emerging Nanotechnologies.

Nanosilver has also been added to bandages to speed healing. That use and others in which the particles are applied to the body are regulated not by the EPA but by the Food and Drug Administration, which is currently considering whether it needs new rules for nanoproducts.

One product, a "Silver Wash" clothes washer made by Samsung, had in the past year drawn particular attention from the EPA because of claims that it sanitized clothes in cold water by releasing tiny charged particles of silver into the wash water.

In a statement yesterday, Samsung said that "only very minute, inactive forms of silver are discharged into the environment" by its washing machine. "Samsung has and will continue to work with the EPA and state regulators regarding regulation of the silver washing machine to maintain full compliance with all applicable laws and regulations," the company said.

About a year ago, Jones said, the EPA decided that such products did not fall under his office's major regulatory tool, the Federal Insecticide, Fungicide, and Rodenticide Act, or FIFRA. That is because FIFRA requires that pesticidal chemicals be proved safe before they are marketed but exempts pesticidal "devices."

In effect, Jones said, the agency considered the washing machine more of a mouse trap than a mouse poison, which meant that it was not subject to regulatory review.

Among those disagreeing with that ruling was Chuck Weir, chairman of Tri-TAC, a technical advisory group for wastewater treatment plants in California. Those plants are subject to penalties if the water that leaves their stations is toxic to aquatic organisms.

In a letter to Jones in January, Weir asked the EPA to rethink its decision on nanosilver. "Silver is highly toxic to aquatic life at low concentrations and also bioaccumulates in some aquatic organisms, such as clams," Weir wrote.

Under pressure from other groups as well, the EPA decided to reconsider.

"We took a second look at the release of silver ions, and it was very clear that this is a pesticide and not a device," Jones said. "Our original determination proved not to be a correct one."