Carbon halides, especially halons (bromofluorocarbons), are compounds known to deplete the ozone layer and contribute to global warming. Appropriate treatments to decompose halon waste is important to protect the environment. A dry process to decompose halon has been developed. Solid alkaline carbonate and hydrate obtained from dolomite were prepared for the reactants to decompose halon and to react with the fluorine and bromine produced by the halon decomposition. Twelve kinds of reactants were obtained by changing the burning temperature and burning time. The amount of the decomposed halon and the conversion were correlated with the pore distributions in the reactants. The distributions of F and Br differed depending on the preparation of the reactants. The difference would be attributed to the reactivity and the diffusion rate of the gases produced by the decomposing halon.