A major, cooperative research project will be completed in 1997 from which an improved understanding will be gained about the dispersion of accidental, dense gas releases at industrial sites (i. e., high surface roughness) during low-wind stable meteorological conditions. The plans for this project were presented by Hanna and Steinberg (1995). Most previous research was limited to releases over smooth surfaces in nearly-neutral conditions (Hanna et al., 1993).