Incinerators of industrial and municipal wastes are the major sources emitting dioxins and dioxin-like compounds. Small-scale incinerators especially for industrial wastes are difficult to operate under well-controlled combustion condition because of fluctuations in composition and feed rate of solid waste, and they are not usually well equipped with the waste gas treatment system. In the present work, we studied the formation of dioxins by the partial combustion of PVC as a model of fly ash formed by the partial combustion, and sought economical ways to suppress the formation of dioxins with hydrated lime. As a result, the lab-scale study revealed that the addition of Ca(OH)(2) into PVC is effective for the suppression of dioxin formation in the partially burned PVC waste. It may be attributed to the removal of free chlorine in PVC through the neutralization with Ca(OH)2 as well as the temperature rise due to the exothermic reaction. Therefore, the addition of hydrated lime into solid wastes prior to the incineration is an economical way to suppress dioxin formation in fly ash for small-scale incinerators.