Incineration reduces the volume of the waste by more than approximately 90% and allows for recovery of much of the inherent energy bound in the waste. However, the incineration process is not a final waste treatment stage. Combustion and air pollution control residues are produced and must subsequently be utilized or landfilled. In principle, at least in Europe, utilization of residues is generally preferred over landfilling, provided this does not give rise to unacceptable environmental impacts or health hazards. In practice, existing regulations, lack of economic incentives, liability issues, residue separation practices and uncertainty concerning the functional properties of the residues as well as limitations concerning the evaluation of the extent and acceptability of the environmental impacts and health hazards of municipal solid waste incinerator residue utilization often serve as obstacles to residue utilization. Due to the potential leaching of contaminants, landfilling of MSWI residues may have long-term consequences to the environment. The disposal solutions chosen for these residues should therefore be sustainable in terms of environmental impact and energy consumption. This may be achieved only through careful consideration of the characteristics of the residues and of the disposal strategies involved (2008).