Sarin human exposure studies

The only published study of the brain structural effects of nerve agent exposure in a human population focused on longterm changes induced in victims of the 1995 Tokyo subway sarin attack (Yamasue et al, 2007). In this event, which resulted in 12 deaths, approximately 5,500 victims were exposed to sarin, and essentially all patients exhibited typical symptoms of acute intoxication (Lee, 2003 Ohbu et al. 

In the approximately 70 years since the discovery of the toxic G agents and 50 years since the subsequent development of the V agents, humans have only occassionally served as test subjects in laboratory studies designed to determine threshold toxic effects associated with low-level (nonlethal) sarin and VX vapor exposures (2-10 min) (Johns, 1952 Sim, 1956 Bramwell et al., 1963). In addition, although the toxic effects of accidental exposures and nonexperimental exposures from terrorist or military attacks are documented, critical information related to the exposure conditions can only be estimated at best. Thus, estimates of human dose-responses to nerve agent vapor exposures from such sources are often associated with significant uncertainty and are of limited utility in predicting health hazard risks. 

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