Such products could include shoe liners, food-storage containers, air fresheners and washing machines. Silver nanoparticles are used in these applications for their bactericidal properties but there's concern that if the material escapes into the aquatic environment it may kill beneficial bacteria and other organisms.

Companies wishing to advertise silver nanoparticle-containing products as germ-killing will have to provide evidence to the EPA that the products do not pose an environmental risk.

This news was first published by the Daily Environment Report and followed up by the Washington Post.