Most sterilization in the medical industry is accomplished by way of heat, usually in the form of steam. A significant alternative to heat-only processing methods is ethylene oxide (EtO) sterilization. As alluded to, this process is usually performed on heat- or moisture-sensitive items.
EtO sterilization uses both temperature (30°-70°C) and the presence of the EtO molecule in a very low humidity condition in a sealed vessel to provide sterility. EtO sterilization cycles are often very long, lasting 10+ hours. Ethylene oxide is very toxic to humans and it is also flammable, meaning that EtO sterilization is extremely dangerous and requires equipment that is specially designed to address these aspects of the process.