The paper gives results of a detailed engineering evaluation of the potential for using an absorption on spent shale process (ASSP) for controlling sulfur emissions from oil shale plants. The evaluation analyzes the potential effectiveness and cost of absorbing SO2 on combusted spent shale in either a fluidized-bed combustor (FBC) or a fluidized transport system (lift pipe) for three retorting processes: Lurgi (lift pipe), Union C (FBC), and Modified In-Situ (FBC). Conceptual designs were completed for the three retorting processes, and the costs of removing SO2 by the ASSP approach were compared to the costs of removing either H2S (including other sulfur species such as mercaptans and thiophenes) or SO2 by the leading conventional sulfur removal processes. A number of significant process variables were identified and evaluated in the study. Study results indicate that ASSP is technically and economically viable compared to conventional technologies for most retorting processes.