Alkylating agents such as formaldehyde, ethylene oxide, and propylene oxide are broad-spectrum biocides active against bacteria, viruses, and fungi, including spores.
Ethylene and propylene oxides are highly reactive gaseous fumigants used to sterilize animal feed, human food, surgical equipment that cannot be autoclaved (eg, endoscopes, gloves, syringes, catheters, tubing, implantable devices, laboratory equipment). Both are noncorrosive. However, ethylene oxide has better penetrability than propylene oxide and, therefore, is more commonly used. For this application, ethylene oxide is mixed with chlorofluorocarbons or carbon dioxide and sold in gas cylinders.
Other gaseous disinfectants (eg, formaldehyde, sulfur dioxide, methylbromide) have been used infrequently because of their toxic or corrosive properties.
Steam sterilization is more effective than low-temperature sterilization technologies using ethylene oxide or hydrogen peroxide gas plasma, and vaporized hydrogen peroxide is the least efficacious. Steam also has the largest margin of safety.