A method for correlating skin exposure to S-mustard vapor with skin damage

An experimental procedure is described as a means for assessing the efficiency of skin-protecting measures against the vapors of hazardous substances. Bis(2-chloroethyl)sulfide (S-mustard) is used as the test substance. A continuous flow of S-mustard vapor is conducted through an exposure cell which is attached to the inner side of a rabbit's ear. From the difference in the concentrations measured before and behind the exposure cell, the absorption and the permeation rate of mustard into the skin is calculated. The skin damage, consisting of a reversible erythema, is quantified by measuring the optical transmittance of the exposed skin area during the following days and correlated with the respective absorption (dose) and exposure parameters (ct-product, with c = 3-50 ng/cm3 and t = 60 and 120 min). Reversible, i.e., completely healing, erythema are evoked by ct-products in the range of 250-2000 ng.min/cm3 corresponding to doses from about 0.1 to 1.1 micrograms/cm2. A comparison with older data reveals that human skin, in this respect, is about eight times more sensitive than the inner side of the rabbit's ear.