Tetrabromoethyleyclohexane (TBECH),which serves as a fire retardant agent, was decomposed in defined and controlled conditions simulating some characteristic temperature and atmosphere conditions of fire development. Under the experimental conditions TBECH converted into a large portion of gases, some volatile condensable products and very little residue. The gases consisted mainly of HBr while light hydrocarbons, light bromine-containing hydrocarbons and C02 were in low concentrations. Among the volatile-condensable products, twenty one components were identified by GC-MS. They were cyclohexadiene, aromaties predominated by benzene and styrene and bromine-containing aromatics, containing one or two bromine atoms. Among the bromine-containing aromatics, the monobromine ones made up a fair concentration, especially bromoethylbenzene. As regards the yield of decomposition products, dehydrobromination highly predominated. High temperatures eaused some additional fragmentation by cleavage of C-C bonds. Secondary reactions of decomposition fragments are also stated.