Dehydrohalogenation during pyrolysis of brominated flame retardant containing polystyrene (brominated high impact polystyrene (HIPSBr)) mixed with polyvinylchloride (PVC) was carried out in a laboratory scale batch process. Thermal and catalytic degradation of HIPS-Br mixed with PVC on carbon composite of iron oxide (TR-00301) catalyst was investigated. The thermal degradation of waste plastics (HIPSBr/PVC) yielded liquid products with 55,000 ppm bromine and 4300 ppm chlorine content in oil. Catalytic degradation (4 g; TR-00301) of HIPS-Br/PVC waste plastics at 430 degreesC produced halogen-free clean oil, which can be used as a fuel oil or chemical feedstock. The main liquid products during catalytic degradation were benzene, toluene, styrene, ethyl benzene, alpha-methyl styrene, butyl benzene, 1,2-dimethyl benzene etc. The average carbon number of the liquid products produced during catalytic degradation (9.3) of waste plastics was less than that of the thermal degradation (10.4) and the density of liquid products was found to be lower during the catalytic degradation than the thermal degradation. The possibility of a single step catalytic process for the conversion of halogenated waste plastics into fuel oil with the simultaneous removal of chlorine and bromine content from the oil was demonstrated. (C) 2002 Elsevier Science Ltd. All rights reserved.