The objective of this research was to develop and evaluate materials and methods to achieve post-explosion identification of explosives reliably and economically through the use of phosphor-coded grains incorporated into the explosive during its manufacture. A coding system of two spotting phosphors and seven coding phosphors was successfully developed. The ability of the coded grains to survive detonation in many different types of explosives was demonstrated, and the complete code was extracted from a single 100-micrometer post-explosion fragment. A method was established for testing grain strength to correlate with field test results, and an optical system was designed for extracting the code from the grains. A laboratory method for manufacturing the coded grains was established, and ten 1- pound samples, each with a different code, were fabricated. A method was developed for applying a coating of polyethylene to the grains to prevent sensitization of the tagged explosives.