The model developed by the authors examines the effect of the various protective actions on expected exposure under number of release and meteorological conditions. The model compares exposure without protection with the expected exposure given a specified emergency response system, and the capacity of the selected protective action to protect. The report analyzed a total of 1134 scenarios , 378 in-place sheltering, and 252 respiratory protection scenarios. The analysis focused on 14 classes of accidents, for a range of meteorological conditions, and for a series of download distances. These 126 accident scenarios were examined for emergency responses involving evacuation, in-place shelter, and respiratory protection. All the scenarios were analyzed assumed that the protective actions would be implemented in a state-of-the-art emergency response system. The findings show that if there is time to complete an evacuation prior to a plume’s impact, evacuation is the preferred alternative. In-place shelters are appropriate in circumstances where time to respond is limited. Pressurized shelters provide the most protection. Respiratory protection actions can be used to greatly reduce the exposure in an accident, but leakage around the filtration system continues to be a problem. Respiratory protection is considered appropriate when used with either evacuation or reduced infiltration in-place shelters. It is recommended that researchers continue to evaluate the effectiveness of various alternatives during a chemical emergency to determine the best protective action alternatives and to provide a baseline for emergency planning.