Abstract: On August 14, 1993, at 9:57 p.m., the San Francisco Fire Department, along with other fire departments, received a call from 911. Engine 17 under the direction of Employee #1 was dispatched to an apartment in San Francisco. Employee #1 and twelve fellow fire fighters were in the hallway. One fire fighter was positioned on the right side of the apartment door, crouched down against the wall with a small charged hose line and the hose nozzle set for a straight stream. Another fire fighter also crouched down with a small charged hose line and his nozzle set for a spray pattern. Employee #1, whose position was on the left side of the door, tried to force open the door with a Chicago door opener. The door would not give away. Another fire fighter who was striking the door with his ax warned the fire fighters that the door was about to give way. He opened the door and two other fire fighters opened their hose nozzles. They swept the apartment for approximately 10 to 15 seconds and advanced into the apartment. According to the fire fighter who was present, a swirling gray cloud advanced toward them like a thrust from a jet engine. The intense gray cloud was a blast of hot steam, air, and gases that rushed from the apartment into the hallway. Employee #1 was directly in line of the blast. He was completely surrounded by the blast, thereby exposing his entire body to its force. The paramedic stated that Employee #1 told him that his facepiece and helmet were dislodged. The investigation team concluded that he was able to quickly replace his facepiece and helmet. He was aware, alert, and communicative when he entered the ambulance. Employee #1 later died from burns that covered 40 percent of his body.