The 5 Rs: Reliable Postdisaster Exposure Assessment

Abstract

Risk is a function of hazard and exposure. Following a disaster, much attention is paid to potential hazards, such as flammable materials, disease vectors, and toxic substances. However, actual risk is determined by exposure to such hazards; there is no risk if there is no exposure. The World Trade Center attacks, the aftermath of Hurricane Katrina, and the spillage of crude oil during the Deepwater Horizon incident in the Gulf of Mexico provide important lessons to engineers who must gauge potential exposure and select interventions to reduce exposures to a broad range of hazards. This paper discusses how exposure assessment varies during the five stages following a disaster (the 5 Rs): rescue, recovery, reentry, reconstruction, and rehabitation. Although every disaster response follows this sequence, the spatial and temporal extent and type of disaster (e.g., immediate threat to human health and safety, long-term threat to ecosystems) determine how an exposure assessment must be conducted.