The M13 Kit Clothing Impregnant contains a dye, p-nitrophenyl-beta-naphtholamine which reacts violently with Cl2 gas at room temp. and thusly functions as a chemical fuze to cause the XXCC-3 mixture to burn exothermically and completely. The principal source of heat is due to the polymerization of the trichlorophenyl isocyanate formed. A kit Cl2 analysis is reported and a Cl2 concentration of 1.3 or greater is needed for kit burn. Thermal decomposition reactions are discussed.