The U.S. Environmental Protection Agency has OK’d 73 more copper alloys as having anti-microbial properties, the Copper Development Association announced.

The EPA has already approved 282 other copper alloys as anti-microbial, which allows manufacturers to make health claims regarding their ability to fight bacteria.

CDA officials said independent testing proved that properly cleaned copper, along with brass and bronze kill 99.9 percent of several potentially deadly bacteria. Possible uses for the materials include doorknobs, sinks and work stations in areas with a high potential for infection, such as hospitals.

A recent U.S. Defense Department clinical trial concluded that copper-containing surfaces may decrease contamination in intensive care units. Research as to whether that translates into fewer infections is ongoing.