Abstract: At approximately 10:30 a.m. on March 27, 1996, Employee #1 moved a supposedly empty 1-ton cylinder scheduled for inspection and reworking from an outdoor stockpile to the service area building. Following standard operating procedures, he removed a valve on the cylinder, which released the chlorine remaining in the tank into the atmosphere. Employees #2 and #3, who were working in the vicinity, evacuated the service area and ran approximately 100 ft to the filling room building, where a general alarm was sounded. Employee #1 also left the service area building and coworkers helped him to a safe area. A fourth employee, who had been trained in handling such situations, put on self-contained breathing apparatus (SCBA) and stopped the flow of gas from the cylinder. All other employees had evacuated to the east side of the property, where ambulances were waiting. Employees #1 through #3 were transported to the hospital. None of the employees working inside the service area had been assigned respirators to wear during the servicing operations.