Experimental blasts were performed with free-hanging charges. The samples taken from metal plates placed at different distances from the center of the explosion were analyzed by gas chromatography with chemiluminescence detection. The results were evaluated with respect to the relative amounts of the dinitrotoluene isomers to each other. In the postblast residue of dynamites that contain nitro-aromatic compounds, the isomers of dinitrotoluene and/or trinitrotoluene were detected. Using an analytical system with enough resolution efficiency to separate and quantify the different isomers, much information can be obtained to identify the explosive. The brand can be determined in comparison with a known sample of explosive or by search in a special database. The best explosive residue for characterization after the detonation consists of unreacted microparticles from the original explosive that are spread into the environment. If the explosive charge is uncovered and free-hanging, such microparticles may be found up to several meters from the center of the explosion. 11 figures, 5 tables, and 9 references