This standard describes sodium chlorite, in either solid (granular, flake, or powdered) or aqueous-solution form, for use in making chlorine dioxide for use in the treatment of potable water, wastewater, and reclaimed water. Sodium chlorite must be packaged, labeled, and registered according to the Federal Insecticide, Fungicide, and Rodenticide Act as administered by the US Environmental Protection Agency (USEPA).