The report gives results of an environmental assessment of afterburner control systems (fume incinerators). It consisted of a review of available data and literature, and the planning of a subsequent experimental program, intended to consist of laboratory and/or field emission measurements to provide data not presently available. The report describes the use of existing data to estimate the potential national usage of afterburners based on emissions. It also reports on an evaluation of field tests data from the files on one local air pollution control agency. Results of the analyses show that the average efficiency of in-service afterburners may be significantly less than that reported in much of the literature.