Silver has proven to be effective in killing bacteria as well as in preventing foul odor in clothes. That’s why silver of nanoparticles are now used in socks, and there are washing machines that can generate this particles. Also, wastewater treatment system use silver nanoparticles in removing ammonia.  A washing machine that used the same way of nanotechnology came under the scrutiny of the US Environment Protection Agency in 2006 for the very same issue. The washing machine supposedly used nanosized particles of a silver as an antibacterial agent on clothes against body odor.

Environment officials were worried because the discharge of this washing machine could prove fatal to aquatic life even at low concentrations. Because of this, the EPA ruled that the machine was a pesticide because of it used silver ions during the washing process for the purpose of killing microbes.