AbstractThe high temperatures and long residence times in the combustion zones of cement kilns have been used for over ten years to burn flammable liquid hazardous wastes, such as solvents, as fuels. Increasing government regulation and control of this technology has actually resulted in expanded use as both waste generators and cement manufacturers have grown more comfortable and confident of this technology. Liquid petroleum and petrochemical wastes have been a part of this liquid fuel stream from its inception. Solid and sludgy petroleum and petrochemical wastes present greater handling difficulties. Nevertheless, the land ban of many of these hazardous wastes has resulted in the motivation to develop solid and sludge handling and processing technologies to allow their use as fuel. These processing options extend back to the point of generation. Changes in filter press media and drying technologies are allowing certain petroleum and petrochemical wastes to be pneumatically introduced into cement kilns. Quality control technologies, including laboratories at both cement kilns and the generating/processing location, have also been a critical part of these developments. As this technology matures, as much as 454,000,000 kg of nationwide capacity for hazardous waste fuel solids is likely to become available.