This study examines the feasibility and potential benefits of using simulation to aid designers of large industrial processes. A demon stration of simulations is provided in the basic oxygen furnace shop and subsequent steel-making operations prior to rolling slabs. We explore three design situations: (1) a new processing technology, (2) the removal of bottlenecks in current operations, and (3) sensitivities of processing to equipment failures. Overall shop productivity and the time workloads of crews and indi vidual process operators are examined. Contrasts are made on these criteria between the current mode of operation and the potential design situations stated above through simulation ex periments. Results of these simulation experiments provide the basis for economic and ergonomic justification as well as indica tions for further improvements in the ergonomic facets of design.