The assessment of major hazards: The lethal toxicity of chlorine: Part 2, model of toxicity to man

Abstract The information available on the lethal toxicity of chlorine to animals and man has been reviewed in a previous paper. In the present paper this information is used to derive a revised estimate for the lethal toxicity to man. A distinction is made between less vulnerable and more vulnerable populations and between different levels of physical activity, with a standard level defined which is applicable to most daytime activity. Mortality is expressed in terms of a lethal toxic load which is a function of concentration and time. The concentrations lethal at the 50% level for a 10 min exposure with standard level of activity are estimated as 433, 173 and 364 ppm for the regular, vulnerable and average population, respectively, and those for a 30 min exposure as 250, 100 and 210, respectively. The probit equation derived for the regular population at the standard level of activity is Y = −8.29 + 0.92 ln L* with L* = Σ C2T where C is concentration (ppm), L* toxic load (ppm2 min), T time (min) and Y the probit. A methodology for the application of the toxicity relationships in hazard assessment is given. T001 . List of symbols The symbols used are as in Reference [1] plus k constant Pa probability of acute death ψ1 inhalation rate factor ψ2 medical treatment factor