Vaporized hydrogen peroxide

Vaporized hydrogen peroxide (also known as hydrogen peroxide vapor, HPV, and by the trademarked name VHP) is a gaseous form of hydrogen peroxide with applications as a low-temperature antimicrobial gas used to decontaminate enclosed and sealed areas such as laboratory workstations, isolation and pass-through rooms,cite web|url=http://www.epa.gov/webmast1/nlconversion_0421/test/opp/vhp_factsheet.htm|title=EPA: Pesticides - Vaporized Hydrogen Peroxide|publisher=US Environmental Protection Agency|accessdate=September 2008] and even aircraft interiors.cite web|url=http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=ADA460897&Location=U2&doc=GetTRDoc.pdf|title=Vaporized Hydrogen peroxide (VHP) Decontamination if a Section of a Boeing 747 Cabin|publisher=US Federal Aviation Administration|accessdate=September 2008] It is registered by the U.S. Environmental Protection Agency as a "sterilant", which the EPA defines as "a substance that destroys or eliminates all forms of microbial life in the inanimate environment, including all forms of vegetative bacteria, bacterial spores, fungi, fungal spores, and viruses". As a sterilant, VHP is one of the chemicals approved for decontamination of anthrax spores from contaminated buildings, such as occurred during the 2001 anthrax attacks in the U.S.cite web|url=http://www.epa.gov/pesticides/factsheets/chemicals/vhp_factsheet.htm|title=Anthrax Spore Decontamination using Hydrogen Peroxide Vapor|publisher=US Environmental Protection Agency|accessdate=September 2008] It has also been shown to be effective in removing exotic animal viruses, such as avian influenza and Newcastle disease from equipment and surfaces. [cite web|url=http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=168702&blobtype=pdf|title=Efficacy of Vaporized Hydrogen Peroxide against Exotic Animal Viruses|publisher=US National Institutes of Health|accessdate=September 2008]

VHP is produced from a solution of liquid hydrogen peroxide and water, by generators specifically designed for the purpose. These generators initially dehumidify the ambient air, then produce VHP by passing aqueous hydrogen peroxide over a vaporizer, and circulate the vapor at a programmed concentration in the air, typically from 140 ppm to 1400ppm depending on the infectious agent to be cleared.cite web|url=http://www.phoenixcontrols.com/documents/HPV%20White%20Paper%20(MKT-0169).pdf|title=HVAC Considerations for Gaseous Decontamination of Laboratory Spaces using Hydrogen Peroxide Vapor (HPV)|publisher=Phoenix Controls Corporation|accessdate=September 2008] By comparison, a concentration of 75ppm is considered to be "Immediately Dangerous to Life or Health" in humans. [cite web|url=http://www.cdc.gov/niosh/idlh/intridl4.html|title=NIOSH:Documentation for Immediately Dangerous to Life or Health Concentrations|publisher=US Centers for Disease Control|accessdate=September 2008] After the VHP has circulated in the enclosed space for a pre-defined period of time, it is circulated back through the generator, where it is broken down into water and oxygen by a catalytic converter, until concentrations of VHP fall to safe levels (typically <1 ppm). Alternatively, the VHP is vented to the outside air, in cases where recapturing of the VHP is not needed.

References