Inhalation toxicity in mice exposed to sarin (GB) for 20-720 min.

Most of the historical data for the toxicity of sarin (GB) was collected for exposure times of <10 min in attempts to establish the utility of and defence against this agent in offensive military use. However, information concerning the toxicity of GB (and other nerve agents) from longer exposures of 1-12 h is critical for all personnel who must work in or close to low-level concentrations of chemical for extended periods and for all personnel, dressed in Individual Protective Equipment, who need to know when, and if, it is safe to take off these cumbersome garments.The data presented for the toxicity of GB to mice for whole-body exposures of 20 min to 12 h are intended to form part of an ongoing, multi-species effort aimed at establishing toxicity estimates for humans for these longer exposure times: LCT50 values of 430, 540, 900, 1210 and 2210 mg.min m(-3) or LC50 values of 21.5, 9.0, 5.0, 3.4 and 3.1 mg m(-3) were obtained for mice for 20-, 60-, 180-, 360- and 720-min exposures to GB, respectively. The data for longer exposures do not follow Haber's rule (LCT50=CT). The 20- and 60-min data fit the 'toxic load model' involving CnT that was established previously from historical data for 0.17-30 min GB exposures to mice. The LCT(50) and LC50 values for 3, 6 and 12 h are progressively higher (toxicity lower) than predicted by either Haber's rule or the toxic load model.