CHAPTER 3: Toxicology of Organophosphorus Nerve Agents

Organophosphorus (OP) nerve agents are highly toxic chemicals that act primarily by inhibiting the enzyme acetylcholinesterase, and the most important routes of exposure are ingestion, inhalation and absorption through the skin. Chemical warfare nerve agents are divided into two main groups, G agents: tabun (GA), sarin (GB), soman (GD) and cyclosarin (GF); and V agents: VE, VG, VM, VR and VX. G agents tend to be more volatile, posing primarily an inhalation hazard, whereas V agents, typified by VX, are more persistent and less volatile so that absorption through the skin represents a particularly hazardous exposure route. Depending on the route of exposure and amount absorbed, nerve agents inhibit cholinesterases in both the peripheral and central nervous system. This chapter covers the toxicity of some of the major nerve agents, drawing on previously unpublished data from the archives of the Defence Science and Technology Laboratory, Porton Down, UK.