The use of soot analysis as an investigative tool in aircraft fires.

Traditionally, carboxyhemoglobin analysis has been used to determine the extent of respiration during a postcrash fire. This is a useful and informative measurement, but advances in the chemical analysis of soot samples provide a new and useful forensic tool for the investigation of deaths by fire. One of the latest analytical techniques is a computer-interfaced pyrolysis mass spectrometry. Soot consists of a high percentage of carbon as well as fragments of the original polymer that are unique to that particular material. Consequently, analysis and identification of the fragment pattern makes it possible to identify the original material from which the soot was generated. In pyrolysis mass spectrometry the soot is pyrolyzed into the ion source and the resulting ion pattern is computer analyzed to identify the polymeric system or systems that generated the soot. Analysis of soot samples collected from the upper respiratory tract of aircraft accident victims and from the accident scene can provide information on the type of toxic insult (identifies specific toxic products), the material(s) that burned and generated the toxic atmosphere, and the relative time of survival following the crash. This technique has been applied to the investigation of fire deaths in a hotel fire and will be used to illustrate the identification of the materials that burned, the toxic products, and the potential for aircraft accident investigations.