This project was designed to evaluate the combustion performance of and emissions from a fluidized bed combustor during the combustion of mixtures of high sulfur and/or high chlorine coals and municipal solid waste (MSW). The effect of sulfur dioxide on the formation of molecular chlorine during co-combustion of fuels was examined in this study. Sulfur dioxide was shown to be an effective inhibitor for the formation of molecular chlorine through the Deacon Reaction and, subsequently, the formation of chlorinated organics. Theoretically, co-firing high sulfur coals with MSW will decrease the possibility of polychlorodibenzodioxin/furan (PCDD/F) formation during the combustion process. A mixture of coal and PVC pellets was burned in a 0.1 MWth bench-scale fluidized bed system at WKU and no detectable amounts of chlorinated organics were found in the flue gas and bed ash. The results from this study indicated the practical effects of using coal as a combustion support fuel when burning MSW.