This paper discusses an environmental control technology which emphasizes the potential application of pretreatment methods instead of the conventionally used post treatment. Some basic aspects such as the nature of the spent shale matrix, and its interaction with retort water, pollutant - precursor relationships and pollution generation mechanisms are discussed. An effort is made to show that the amount of pollutants produced and the subsequent immobilization of these pollutants on the spent shale surface is possible by proper matrix modification. Such an environmental control technology could include the use of additives for the interruptions or modification of pollutant pathways, or the se of the autocatalytic effect of the clays inherent in the system. Optimization of operating conditions is shown to affect pollutant generation greatly.