Final answer:
Ethylene oxide is the chemical used for gas sterilization of equipment that cannot be autoclaved safely and is a suspected carcinogen.
Step-by-step explanation:
The chemical used for gas sterilization of equipment that cannot be autoclaved safely is ethylene oxide. Ethylene oxide is a powerful alkylating agent which modifies biochemicals through S₁₂ reactions, resulting in the death of microorganisms. It is used extensively for the sterilization of medical equipment such as catheters, surgical instruments, and various disposable items that are sensitive to heat, as it can penetrate plastic packaging and doesn't require high temperatures. However, ethylene oxide is also a suspected carcinogen and is explosive in nature, which entails that its use must be carefully managed, and objects sterilized with it should be adequately aerated to remove any residual gas.
Supercritical carbon dioxide (scCO₂) is also noted for its sterilization properties, particularly because it is nonreactive, nontoxic, nonflammable, and operates effectively at low temperatures. While scCO₂ is gaining popularity for various applications due to these benefits, ethylene oxide remains the primary chemical used when gas sterilization is required in situations where autoclaving is not feasible.