On March 8, 2001, a 38-year-old male career fire fighter (the victim) fell through the floor while fighting a structure fire; and died 12 days later from his injuries. At 1231 hours, Central Dispatch notified the career department of a structure fire with reports of occupants still inside. The Assistant Chief arrived on the scene along with Engine 70 and assumed Incident Command (IC). The IC immediately called for the second alarm, began conducting the initial size-up of the structure, and confirmed heavy fire in the left front section. At that time, the neighbors approached the IC and informed him that the occupants were trapped inside. The IC ordered the fire fighters on scene to commence search and rescue efforts, and then verified the stability of the structure through radio and face-to-face communications. Engine 68 arrived in the scene at approximately 1250 hours with an Assistant Chief and the victim. The Assistant Chief provided tactical command of the fire ground, and along with the victim, conducted search and rescue operations. Other crews conducted searched with a thermal imaging camera of the first floor and basement level of the residence with no sign of any occupants. During these searches the stability of the structure was diminishing due to the intense fire that was now venting through the roof. Fire Fighter #3 and the victim were at the front entrance conducting a defensive attack as the third emergency evacuation signal was sounded. The neighbors were still insisting to the IC and fire fighters that the occupants were trapped inside, and one of the occupants was handicapped. The victim and one other fire fighter conducted another search of the structure. The heat and flames were now extending from the basement level of the first floor when the fire fighter's low air alarm sounded. The victim and the fire fighter were backing out of the structure when the floor beneath the victim gave way. causing him to fall through the floor and become trapped in the basement. Attempts were made from the first floor to rescue the victim by utilizing a handline and an attic ladder, but they were unsuccessful due to the intense heat and flames. Two Rapid Intervention Teams (RIT #1 & RIT #2) were deployed simultaneously from separate entrances into the basement to perform a search and rescue mission for the downed fire fighter. The RITs were able to locate and remove the victim on their initial entry. He sustained third degree burns to over half of his body and died 12 days later. NIOSH investigators concluded that to minimize the risk of similar occurrences, fire departments should: 1. ensure that Incident Command continually evaluates the risk versus gain during operations at an incident; 2. ensure that a separate Incident Safety Officer independent from the Incident Commander is appointed; 3. ensure that fire fighters are trained in the tactics of defensive search; 4. ensure that fire fighters performing fire fighting operations under or above trusses are evacuated as soon as it is determined that the trusses are exposed to fire; 5. ensure consistent use of Personal Alert Safety System (PASS) devices at all incidents and consider providing fire fighters with a PASS integrated into their Self-Contained Breathing Apparatus which provides for automatic operation; 6. ensure that personnel equipped with a radio, position the radio to receive and respond to radio transmissions.