To gain an understanding of the harmful gasses released from a flame resistant clothing material during a simulated flash fire exposure, TPACC developed an off-gassing test method based on the Heat Transfer Performance (HTP) test, commonly known as the Thermal Protective Performance (TPP). The TPP device is utilized to expose material swatches to radiant heat and flame from 3-5 seconds. Modifications of the instrument system allow for the collection of hydrogen cyanide, hydrogen chloride and volatile organic off-gasses in an impinger with solvent. The acid gases are fully quantified. Organics are identified and a semi-quantitative estimate is made using GC/MS analysis. The amount of analyte measured in the solvent depends on fabric composition. This new method provides for analysis of off-gassing from fabrics during a more realistic simulation of a flash fire exposure.