For chemical warfare agents, NARAC products show the near-term health effects that could be experienced (calculated based on the peak outdoor air concentration experienced during any 15-minute period); areas where isolation and protective actions may be warranted, areas where use personal protective equipment by emergency worker should be considered, and regions where surface contamination may be encountered. For certain agents, a product is available that addresses health hazards from absorption of the agent deposited on the skin.
Lethal doses are based on public exposure guidelines:
- LD85 and LD50: Lethal doses for 85% and 50% of the exposed population
- AEGLs: 60-minute EPA Acute Emergency Guideline Levels
Exposure calculations assume that individuals remain outdoors in the same location throughout the plume passage.
References:
AEGLs: http://www.epa.gov/oppt/aegl/
LDs: Chemical Warfare Agent Toxicity Estimates for the General Population, Douglas R. Sommerville, Sharon A. Reutter, Ronald B. Crosier, Erin E. Shockley, John J. Bray, Edgewood Chemical Biological Center, ECBC-TR-442, June 2005 (Restricted distribution to U.S. Government agencies and their contractors).