Abstract: On August 2, 1988 seven employees were working at their respective job assignments throughout the Allied Signal Corporation - South Works generation 113/114 unit. Employee #1 was working at Reactor #2 on the fourth deck taking pipe down, west of Reactor #1. Employee #2 was attending a first aid training course in the administration building, located northeast of the process area. Employee #3 was loading drums in the packaging building located west of the unit. Employee #4 was cutting out pipe on the 3rd floor of Reactor #2. Employee #5 was working in the control room immediately north of the process units bringing up reactors. Employee #6 was near the mobile equipment shop riding an electric cart. Employee #7 was working in the packaging building west of the unit. An explosion occurred in the generation room of the 113/114 unit, apparently resulting from a chemical reaction between chlorine and hydraulic oil at the G-113 chorine feed pump, a Durco Meter PD #2, plunger/diaphragm metering pump. Failure of one diaphragm and cracks in the other due to wear resulted in the mingling of oil and chlorine between the discharge side of the chlorine pump and the pressure side. Apparently a blow out of a pipe segment and four valves occurred there. Seven employees were hospitalized and diagnosed as having been exposed to chlorine. Employee #2 experienced bronchospasms and coughing. Employee #6 had bronchospasms and a burning sensation in the lungs complicated by a previous medical condition. Employee #5 had conjunctivitis. Employees #1, #3, #4 and #7 were hospitalized for observation. No pulmonary edema or pneumonia was evident in any exposed employee.