Washington — Proponents of antimicrobial copper alloys are hailing a recent decision by the U.S. Environmental Protection Agency to approve the alloys' registration.
According to the Copper Development Association, the EPA's decision acknowledges that copper, brass and bronze are capable of killing harmful and potentially deadly bacteria.
Harold Michels, the CDA's senior vice president of technology and technical services, said the EPA's ruling is significant because it recognizes that the alloys can eliminate “super bugs.” He said these bacteria cause up to 100,000 deaths per year and cost $20 billion to $30 billion per year in additional medical bills.
“It's the first time that the EPA has registered a material to make public health claims that (the alloys) kill organisms,” Michels said. “The only things that can say that are gases and liquids, which are sanitizers and sterilizers. This is a really significant recognition of a material that can actually perform this function. If you apply a sanitizer or a sterilizer to a surface, it's gone, but two seconds later, someone can come by and re-infect the surface.”
The EPA based the registration on independent laboratory testing using EPA-prescribed protocols that demonstrate the metals' ability to kill specific disease-causing bacteria, including Methicillin-resistant Staphylococcus aureus, or MRSA, according to the CDA. MRSA is one of the most virulent strains of antibiotic-resistant bacteria and a common cause of hospital- and community-acquired infections.
Statistics from the U.S. Centers for Disease Control and Prevention estimate infections acquired in U.S. hospitals affect 2 million individuals every year, according to the CDA.
Testing under EPA-approved protocols demonstrates that copper, brasses and bronzes are effective against a number of disease-causing bacteria, the CDA said. One study showed that more than 99.9% of MRSA “super bugs” died within two hours at room temperature on copper alloy surfaces.
“When cleaned regularly, antimicrobial copper alloys surfaces kill greater than 99.9% of (specific) bacteria within two hours, and continue to kill more than 99% of (these) bacteria even after repeated contamination,” the EPA said in its registration. “The use of a copper alloy surface is a supplement to and not a substitute for standard infection control practices; users must continue to follow all current infection control practices, including those practices related to cleaning and disinfection of environmental surfaces. The copper alloy surface material has been shown to reduce microbial contamination, but it does not necessarily prevent cross contamination.”
The CDA said potential uses for the alloys include faucets, sinks and workstations, adding that the alloys can help reduce the amount of disease-causing bacteria in patient rooms.
While the antimicrobial copper alloys have shown promising results on “touchable” surfaces, ongoing study is necessary to determine their potential effect on potable water piping, according to Michels.
One person who remains skeptical is David Yates, owner of F.W. Behler, in York, Pa., and a regular columnist for Contractor Magazine.
“New copper does indeed offer direct-contact limited protection,” Yates said. “It does not offer eradication of free-roaming bugs, and once biofilms build up inside the piping, the protective effects are negated with the exception of the outermost fringes of the biofilm where it is in direct contact with the copper tubing.
“The danger I see in this over-reaching declaration is that those who abuse potable water quality — like the use of open combined dual-use potable hydronic systems — will now hang their collective hats on this by adding a few feet of copper to ‘sterilize’ their system.”The CDA is under way with the University of Southampton and others on a very preliminary study of copper alloys' effects on potable water piping systems, Michels said.
“As far as potable water, we're very reluctant to make any kind of sweeping claims because it depends on so many factors,” Michels said.
Yates cautioned that copper or silver ionization and chlorine dioxide are the only two types of potable water treatment that ensure the eradication of bacteria such as Legionella in potable water.
The CDA also is conducting a laboratory study comparing the antimicrobial effects of all-copper air conditioning systems versus conventional aluminum fin copper tube systems, Michels said.