Skin permeation of oxides of nitrogen and sulfur from short-term exposure scenarios relevant to hazardous material incidents

Abstract

Permeation of oxides of nitrogen and sulfur gases through skin and the consequences of dermal exposure are still poorly understood. We measured the penetration profile of three common industrial gases through skin, for short-term exposures relevant to HAZMAT scenarios. Time variations of gas concentration, clothing effects, temperature and humidity on epidermal absorption and penetration were assessed. Fabric off-gassing profiles were also investigated. The results show oxides of nitrogen (NO and NO₂) at airborne concentrations up to lethal inhalation levels (e.g. 3000 ppm) have little skin penetration ability. Skin absorption and reservoir effects were noted. Skin exposed to SO₂ (3000 ppm/30 min) shows negligible skin absorption or penetration. Fabric on skin marginally increased SO₂ absorption and subsequent ventilation did not reduce the absorbed fraction. Increased temperature and humidity had limited additional effect on skin penetration. Importantly, clothing demonstrated sink properties, especially for SO₂. Short-term skin exposure relevant to accidents will not significantly contribute to body burden. The greatest concern will likely be off-gassing of chemical-laden fabric for asthma suffers. The risk-based management approach is to avoid potential secondary inhalation from fabric off-gassing by removal of outer layer of bulky clothing. Decontamination and moving into an area of enhanced ventilation may also be advised.