This paper presents practical and scientific approaches for cleanup and site restoration following terrorist events. Both approaches are required in actual emergency situations and are complementary. The practical examples are taken from the May 2003 second biannual national emergency exercise, Top Officials 2 (TOPOFF 2), which occurred in Chicago, Illinois, and Seattle, Washington. The scientific examples are taken from the Department of Energy sites at Rocky Flats, Fernald, and Los Alamos where cleanup initiatives based on scientific approaches and community input are underway. Three examples are provided to explain, from a practical standpoint, how decisions during the exercise had to be made quickly, even though the alternatives were not always clear. These examples illustrate how scientific approaches can be integrated into the resolution of these dilemmas. The examples are (1) use of water to wash city roads and freeways contaminated with plutonium, Am, and Cs; (2) decontamination of large public ferries that passed through a radioactive plume; and (3) handling of wastewater following decontamination within a city. Each of these situations posed the need for an immediate decision by authorities in charge, without the benefit of community input or time for an analysis of the important pathways of exposure. It is evident there is a need to merge the practical knowledge gained in emergency response with scientific knowledge learned from cleanup and site restoration. The development of some basic scientific approaches ahead of time in the form of easy-to-use tools will allow practical decisions to be made more quickly and effectively should an actual terrorist event occur.