GD (Soman or 1,2,2-trimethyl propyl methylphosphonofluoridate) is an organophosphate nerve agent. It is a colorless, volatile liquid. The physical and chemical properties, toxicokinetics, and toxicity of GD are discussed in detail by CDEPAT (1994), Marrs et al. (1996), and Somani (1994). Human-toxicity estimates have been derived for percutaneous vapor exposures, vapor inhalation exposures, and percutaneous liquid exposures. Only a few toxicity end points were considered (for example, lethality in animals and incapacitation). The subcommittee's assessment of the scientific validity of CDEPAT's human-toxicity estimates for GD is discussed below.
CDEPAT's proposed LCt50 estimate following percutaneous exposure to GD vapors is 2,500 mg-min/m3, assuming that soldiers are wearing light clothing, temperatures are moderate, and exposure durations are 30 to 50