Estimates of the Toxicity of Hydrocyanic Acid Vapors in Man

Abstract : When the data on which the internationally accepted LCt50 of inhaled hydrocyanic acid (AC,HCN) vapors in man were reviewed and the figures published widely in scientific journals were examined, it was decided that more valid estimates of the toxicity of HCN in man should be developed. LCt's for 1%, 16%, 30%, 50%, 84%, and 99% of an exposed population for exposure times of from 0.5 to 30 minutes were derived. Because of the paucity of data on controlled experiments with man, it was necessary to use animal data. Among the assumptions made were that man falls into the species that are relatively resistant to HCN; that man is at least as resistant as the goat; and that man is at least four times as resistant as the mouse. The values derived are given. (Author)