Publisher Summary Historically, public opposition to the siting and operation of MSW incinerators has been based on concerns over the emissions of contaminants to the atmosphere. During the late seventies and early eighties, much of this concern was justifiable in light of the poor performance of inadequately designed and operated facilities. In addition, the enhanced ability of scientists to detect trace contaminants at very low concentrations placed further pressure on the industry to reduce emissions. During the past decade, the industry has responded positively. Most of the concerns related to emissions have been addressed by optimizing incinerator design and operation through improved combustion control. This and the implementation of new air pollution control technologies have dramatically reduced atmospheric emissions. The advent of more efficient incinerator operation and better designed air pollution control systems has resulted in concern shifting from air emissions to the disposal of the captured residues. Today, ash disposal is one of the major issues limiting the acceptance of new incinerator facilities.