The Process Model Projection Technique (PROMPT) is one of four stationary source emission and control cost forecasting models developed by the Air and Energy Engineering Research Laboratory for the National Acid Precipitation Assessment Program (NAPAP). PROMPT projects air pollution and costs for industrial combustion and industrial processes. The outputs are provided for 1980 (baseline), 1985 (forecasted, not actual), 1990, 1995, 2000, 2010, and 2030. Version 3.0 of PROMPT has been tested to verify that its source code and algorithms are functioning as intended. The reader is cautioned to remain aware that the results obtained from this version of PROMPT are subject to change upon release by EPA of the next, updated version using the 1985 data baseline. Software Description: The program is written in FORTRAN for implementation on IBM XT/AT compatible equipment, using DOS 3.10 operating system.