EPA registration allows the manufacturers of copper alloys to legally make public health claims as to the health effects of these materials.
Copper is germicidal via the oligodynamic effect. The oligodynamic effect is a toxic effect of metal-ions on living cells, algae, molds, spores, fungus, virus, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations. This antimicrobial effect is shown by ions of: mercury, silver, copper, iron, lead, zinc, bismuth, gold, aluminium and other metals.
The exact mechanism of action is still unknown. Data from silver suggest that these ions denature proteins (enzymes) of the target cell. Viruses in general are not very sensitive. The toxic effect is fully developed often only after a many hours.