Four volunteer firefighters died when they were trapped by a partial floor collapse during a structure fire in Brackenridge, Pennsylvania, on the morning of December 20, 1991. All four were members of a mutual aid truck company that had responded to the early morning incident and were assigned to prevent fire extension from the basement to the ground floor of a 2-story building. Although they were wearing full protective clothing and using self-contained breathing apparatus, it appears that they were overwhelmed by the severe fire conditions that erupted when a section of the ground floor collapsed into the basement. The collapse cut off their primary escape path, and the fire burned through their hose line, leaving them without protection from the flames.