BACKGROUNDUtilization and safety storage of hazardous waste like hospital incineration fly ash is an important ecological problem. In Poland the dominant process of waste storage is landfill. The characteristics of the raw waste as well as their transformation products after various utilization processes is very important to minimize the environmental impact. RESULTSThe research presented compares product stabilization obtained using two investigated technologies: thermal plasma treatment in a vitrification process, and solidification with Portland cement as the binder in hydration and granulation processes. The leachability of six heavy metals (Zn, Pb, Cu, Ni, Cd, Cr), indicated in the Council Decision 2003/33/EC as the main parameters influencing the environment, were studied. CONCLUSIONThe most stable products were vitrificates-immobilization exceeded 90%. The immobilization of heavy metals in solidified waste using Portland cement in a hydrated process were estimated at between 60 and 90%. (c) 2015 Society of Chemical Industry