Ethylene oxide antimicrobial agent, molecular model. Ethylene oxide (also known as oxirane, epoxyethane, dimethylene oxide) is an industrial chemical used as a sterilant, killing bacteria, mould and fungi. It is mostly used in sterilising medical supplies such as bandages, sutures and surgical equipment. It is also used in manufacturing other chemicals, such as the car refrigerant ethylene glycol found in antifreeze. Ethylene oxide has the chemical formula C2H4O. Atoms are represented as spheres and are colour-coded: carbon (C, grey), hydrogen (H, turquoise) and oxygen (red).