Accidental exposure reports, nerve agents

Marrs et al. (1996) and Sidell (1996) have provided an extensive overview of human smdies of nerve agent exposures conducted by the US and the UK military as well as accidental exposures that occurred at production or test facilities. Although this report does not come to any conclusions about long-term effects, there is no indication that asymptomatic exposures to nerve agents have produced long-term, adverse health effects. This is the same conclusion reached by the National Academy of Sciences, committee that reviewed the then available literamre, to include the EEG smdies of Burchfield et al. (1976) and Duffy et al. (1979). They stated that while there may be subtle... 

There are clear ethical constraints that prevent human research that could definitively answer the questions of concern regarding the military operational and civilian health risks of exposure to low-levels of chemical warfare nerve agents. Only three sources of relevant human data are available for analysis. These data are from either past human volunteer studies, reports based on accidental exposures, or reports of the consequences of malicious releases of the agents. While these sources are valuable, the data have some limitations for deriving dose-response relationships because of inferior analytical and clinical methods or the lack of precise estimates of exposure. 

There are only a few reports in the open literature on the effect of oximes in nerve agent-exposed humans. Pralidoxime chloride was very effective in reactivating erythrocyte AChE in individuals exposed to sublethal intravenous or oral VX while this oxime was substantially less effective in humans exposed to IV sarin (Sidell and Groff, 1974). Accidental sarin exposure by inhalation resulted in an initial progressive deterioration (coma, apnea) of the patient despite atropine and 2-PAM treatmentand substantial recovery of erythrocyte AChE activity (Sidell, 1974). It took several hours until the patient s condition improved. Sidell also reported an accidental oral soman exposure. A lethal dose of diluted soman splashed into and around the mouth of an individual, resulting in coma, bronchoconstriction and respiratory depression, which was successfully treated with repeated atropine injections. 2-PAM (2 g IV) had no effect on inhibited erythrocyte AChE. 

Most of the information on the effects of nerve agents on organ systems in humans is derived from studies done in the post-World War II period, from reports of people exposed to pesticides, or from clinical evaluations of accidental exposures of people who worked in nerve agent-research laboratories, manufacturing facilities, or storage areas or depots (Table 5-6). Some organ systems have been studied more intensively than others for some organ systems there are few human data. For example, for the musculoskeletal system, there is a plethora of data from animal studies and studies in isolated neuromuscular preparations, but study results are difficult to apply to a human clinical situation. 

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