Abstract: At approximately 10:00 a.m. on July 1, 1991, Employee #1 was replacing a filter on an Amsco gas sterilizer, which used 12 percent ethylene oxide and 88 percent Freon. Prior to replacing a filter, Employee #1 discharged the gas line. The line recharged, unknown to Employee #1, and while removing the filter, he was hit in the chest with 60 psi of gas. He was wearing only a face shield. Employee #1 turned off the gas and collapsed near the eye wash. When Employees #2, #3, #4, #5, and #6 heard the explosion, Employee #6 told Employees #2, #3, and #4 to evacuate and call the designated emergency number. Employees #5 and #6 went to assist Employee #1 without donning any personal protective equipment. Employee #6 helped Employee #1 wash out his eyes while Employee #5 went out to call for specific assistance. The employees were admitted to the emergency room for possible ethylene oxide exposures and then released.