Field observations of the persistence of Comp B explosives residues in a salt marsh impact area

Field observations of weathering Comp B (RDX/TNT 60/40) residue were made on a live-fire training range over four years. The Comp B residue was formed by low-order detonations of 120-mm mortar projectiles. Physical changes were the disaggregation of initially solid chunks into masses of smaller diameter pieces and formation of red phototransformation products that washed off with rain or tidal flooding. Disaggregation increased the surface area of the residue, thereby increasing the potential for dissolution. The bulk of the mass of Comp B was in the craters, but solid chunks were scattered asymmetrically up to 30 m away.