[en] An emergency response computer code has been implemented at the Oak Ridge National Laboratory to assist decision makers during the accidental airborne release of an agent. This paper describes the necessary steps to run the FORTRAN 77 computer program that simulates the movement of a substance over time. This series of steps involves obtaining the appropriate meteorological and other input data for the program execution of the program, and analysis of the results. The computer program runs on the IBM PC and the HP 9000 supermicro computer. Both of these computers communicate with a PDP 11/23, which stores real-time meteorological data, to obtain data necessary to run the computer code