Noteworthy progress has been made recently toward understanding and quantifying the smoke toxicity factors involved in fire hazard assessment. Such progress has led to increased attention to the significance of fire growth parameters for toxic hazard. Methodology has been proposed to use fire test data, including information on the toxic potency of smoke in engineering calculations for the assessment of overall fire hazard. Confidence in the methodology may evolve from comparison with full-scale fire tests as well as from human fire fatality experience. This report addresses fire modeling, fire testing, smoke toxicity testing, fire hazard assessment, and fire risk assessment. In the assessment of potential toxic hazards in the event of fires in mass transit vehicles, the report concludes that selection of candidate materials should be based on analyses using both toxicological and engineering considerations.