Abstract: An employee began the routine task of changing a chlorine tank. At about 2:00 a.m., a 1 ton cylinder began to leak. The employee enlisted the help of another employee on duty. At 2:10 a.m., the employees put on SCBA. One respirator, however, was not working. At 2:15 a.m., Employee #1, wearing SCBA, entered the chlorine room. Within minutes, the chlorine entered the SCBA's face piece. The employee quickly removed the respirator and ran from the room. Once outside, he vomited. His throat burned, his skin tingled, and he was coughing. At 4:00 a.m., he was transported to an emergency room, where he was given oxygen and a mist. He did not know what the mist contained. He returned to work and completed his shift. His throat began to feel better on August 6, 1991. He was still coughing (dry cough) on August 7, 1991, and had not received any medical attention after visiting the emergency room. Thirty-two pounds of chlorine leaked from the 1 ton cylinder during the incident.