Abstract: Employee #1 responded to an ethylene oxide (ETO) leak in the tank room of the sterile processing department of a general and surgical hospital. Employee #1 entered the tank room with an uncalibrated ETO sensor to determine the location of the leak. The employer did not provide nor did Employee #1 wear any respiratory protection. Once Employee #1 entered the tank room, the sensor alarm sounded and he left immediately. The leak was due to an improperly loaded gas sterilizer and a piece of cloth that became caught between the sterilizer door frame and door seal. Employees #1 and Employee #2, who also worked in the sterile processing department, were exposed to an unknown concentration of ETO.