Chemical weapons fall into distinct categories and include respiratory toxicants, vesicants, nerve agents, metabolic poisons, rodenticides, and both inorganic and organic arsenicals. Common sites of injury following exposure to these agents are the skin, lung, and eyes. This chapter provides an overview of chemical threat agents, with a focus on vesicants and nerve agents that have been used and of other chemical threats (e.g., metabolic poisons, arsenicals, rodenticides, pulmonary agents, and halogenated gases). Organophosphate compounds such as nerve agents have a high affinity for the serine hydroxyl residue in the esteratic or active site of acetylcholinesterase, leading to inhibition of activity and buildup of the neurotransmitter acetylcholine. Vesicants including sulfur mustard (bis‐2‐chloroethyl sulfide), nitrogen mustard, and lewisite are cytotoxic blistering agents. The severity of injury due to these agents often depends on routes of exposure, concentrations of the blistering agent, time following exposures, and environmental conditions.
