During planning activities or in response to an actual chemical incident, selection of an appropriate exposure guideline on which to make protective action decisions may greatly affect the choice and/or level of response activity. For example, for many people evacuation from their homes can be a very traumatic and disruptive event, with a set of risks associated with their evacuation. Decisions regarding re-use of critical infrastructure facilities such as water treatment, power, and government facilities, as well as hospitals, schools, day care facilities, and prisons can pose difficult risk management questions. Selection of health-based exposure guidelines that are very stringent could result in an unneeded evacuation or inappropriately focused response. Conversely, selection of values that are not stringent enough for final clearance goals may lead to long-term health effects in an exposed population.
Familiarity with the various human health-based exposure guidelines and development of emergency plans and how they might be implemented will help facilitate these decisions in an actual chemical event. Fully understanding the derivation, uncertainties, and possible limitations of an exposure guideline is critical to determining its appropriateness for use in a specific situation.