This paper first describes the SEM/EDS equipment used in the work described in this paper. This is followed by a description of PRR particles. The description notes that in virtually every case, pyrotechnic reactions, either in fires or explosions, produce sufficient thermal energy to yield molten reaction products. The distribution of particle size depends on the nature of the pyrotechnic composition and the conditions under which they are produced. One section of the paper explains the process of PRR particle identification, followed by the presentation of a case example of the use of SEM/EDS in the characterization of PRR particles. The authors conclude that the SEM/EDS methodology to identify and analyze PRR particles in the course of investigating incidents that involve pyrotechnic materials can provide information with a degree of sensitivity and specificity that is not possible with other commonly used techniques. Although a few particle assignments may be uncertain, conclusions can collectively be drawn with a high degree of confidence. 4 figures, 3 tables, and 20 references