Gaseous disinfectants/sterilants are chemical agents in gaseous form used to sterilize/disinfect heat-labile items (plastics, electronic equipment, delicate instruments) that would be damaged by moist or dry heat, by penetrating packaging and reaching all surfaces of complex-shaped items.
Examples:
Ethylene oxide (ETO) — the most widely used gaseous sterilant in hospitals/industry; a highly penetrating, alkylating agent that kills microorganisms (including spores) by alkylating nucleic acids and proteins, disrupting normal cellular metabolism and reproduction. Used to sterilize heat-sensitive medical devices, plastic disposables, catheters, and electronic equipment. Requires controlled temperature, humidity, and gas concentration, and a prolonged aeration period after exposure to remove residual toxic gas (ETO is flammable, explosive, carcinogenic, and irritant to tissues, so operator safety and residue clearance are important concerns).
Formaldehyde gas — used for fumigation of rooms/enclosed spaces (e.g., operation theatres, isolation wards, laboratory safety cabinets) and for low-temperature steam-formaldehyde sterilization of heat-sensitive equipment; also alkylates microbial proteins/nucleic acids; pungent, irritant, and a suspected carcinogen, limiting its current use.
Hydrogen peroxide gas plasma / vaporized hydrogen peroxide — a modern, low-toxicity alternative increasingly used for sterilizing heat- and moisture-sensitive medical instruments (e.g., endoscopes), producing free radicals that damage microbial components; leaves no toxic residue (breaks down to water and oxygen).
Beta-propiolactone — an alkylating gaseous/liquid agent, used for sterilizing vaccines and some biological products, and for room fumigation, though largely superseded due to toxicity/carcinogenicity concerns.
Common principle: these agents typically act by alkylation of nucleic acids and proteins, disrupting replication and essential cellular functions, and are chosen specifically because they achieve sterilization at low temperature, avoiding the heat/moisture damage that would occur with autoclaving.
