The three aspects of accidents in chemical process industries which cause most serious damage-explosions, fires, and toxic releases-can all be controlled to some extent if greenbelts are present around the affected industry. We have recently developed and validated a system of methodologies for greenbelt design. In this paper we present the application of these models in designing greenbelts and forecasting their role in cushioning the impact of accidental release of toxic gases. With properly located and designed greenbelts as much as 33% of the accidental release of SO2, 43% of H2S, and 51% of NH3 under stable atmospheric conditions (in which the dispersion is very slow and the release thus has maximum toxic impact) can be absorbed. (C) 2000