The pyrolysis of brominated flame retardant containing high impact polystyrene (HIPS-Br) mixed with poly(ethylene terephthalate) (PET) was performed at 430degreesC under atmospheric pressure by a batch operation. The addition of PET to HIPS-Br affected significantly the formation of decomposition products and the degradation behavior of HIPS-Br. We have found the following observations on the addition of PET during the pyrolysis of HIPS-Br: (i) the rate of formation and the yield of liquid products decreased, (ii) the residue and gaseous products formation increased, (iii) the average carbon number (Cnp) of liquid products reduced from 12.5 to 9.1, (iv) the yield of high molecular weight hydrocarbons (C-16-C-20) decreased and the amount of hydrocarbons from C-6 to C-10 doubled, (v) heavy waxy compounds were formed on the top of the glass reactor wall in addition to the solid residue on the bottom of the reactor, (vi) antimony compounds were observed in the solid residue, as opposed to the formation of antimony tribromide (SbBr3) detected in the liquid products of HIPS-Br in the absence of PET. We attempted the debromination of brominated liquid hydrocarbons using iron and calcium based carbon composites for the production of halogen free liquid hydrocarbons, which can be used as a feedstock in a refinery or as a fuel. (C) 2003 Elsevier B.V. All rights reserved.