Fire properties of 4 natural sorbents contg. bark and fibers of pine, modified lignin, bark of mixed tree and of cork tree were detd. The explosion characteristics were studied in a cone calorimeter and a smoke chamber. During thermal degrdn. of pure sorbents, the large amts. of C oxides and phenols were released. In addn., hydrocarbons and polycyclic arom. hydrocarbons were also contained in the thermal decompn. products of used sorbents.