The paper gives results of a study (part of a multiphased EPA study of the acid rain problem) the objectives of which were to (1) identify and characterize existing industrial sources of SO2 emissions, (2) identify the control techniques that can be used to reduce SO2 emissions from these sources, and (3) estimate the SO2 emission reduction potential and associated costs based on applying these controls. Only a portion of the SO2 sources were investigated in detail; simplifying assumptions were made about the balance of the SO2 sources studied. The availability of low sulfur fuels (i.e., physically cleaned coal and low sulfur fuel oil) was not evaluated. In addition, since sites were not visited, the remaining useful lives of the sources were not determined and average flue gas desulfurization unit retrofit factors were estimated.