Dermal absorption of fumigant gases during HAZMAT incident exposure scenarios—Methyl bromide, sulfuryl fluoride, and chloropicrin

Abstract

Accidental or intentional releases of toxic gases or vapors are the most common occurrence in hazardous material (HAZMAT) incidents that result in human injuries. The most serious hazard from exposure to gases or vapors is via the respiratory system. Dermal uptake, as a secondary route, is still a concern, most acutely for the unprotected public. There is a limited evidence base describing skin absorption of toxic gases and vapors in HAZMAT exposure scenarios, which are relatively brief compared with traditional test periods for skin absorption studies. We describe research designed to provide experimental data to support decision-making by first responders regarding skin decontamination in HAZMAT-focused exposure scenarios involving toxic gases. We present findings for three common fumigants, methyl bromide, sulfuryl fluoride, and chloropicrin assessed using an Organization for Economic Co-operation and Development in vitro toxicology protocol utilizing human skin and gas/vapor exposures. Results indicate that for atmospheric concentrations that would be lethal via inhalation (LCLo), intact skin provides an excellent barrier to exposures up to 30 min, with little influence of common clothing fabric and high temperature and humidity conditions. The findings may challenge the current HAZMAT dogma requiring mass personal decontamination by strip and shower for short-term exposures to sulfuryl fluoride and chloropicrin gas/vapor.

Is the skin an important exposure route for workers during cyanogen fumigation?

“…Empirical evidence regarding the kinetics of transdermal permeation of fumigant gases and vapors is extremely limited, in particular for cyanogen. We have previously shown with other fumigants that undamaged skin provides an excellent barrier to exposures at high atmospheric concentrations (lethal by inhalation) . We previously reported the first skin exposure to phosphine gas, under exposure concentrations relevant to accidental release or hazardous material incident scenarios (50 ppm, concentration immediately dangerous to life and health (IDLH) and 1000 ppm lowest lethal concentration (LO Lo ).…”

“…These outcomes aligned with those described here for cyanogen skin exposure to 1000 ppm cyanogen, however by comparison the relative toxicity reported in a rat study showed no deaths occurred after exposed to cyanogen at 1000 ppm . In contrast, our previous work for the fumigants sulfuryl fluoride and methyl bromide demonstrated the potential to penetrate skin within relatively brief exposure periods (30 min) . Furthermore, occupational exposure to methyl bromide and sulfuryl fluoride during fumigation activities have reportedly resulted in worker poisonings, in some cases specifically by the dermal route .…”

“…We have previously shown with other fumigants that undamaged skin provides an excellent barrier to exposures at high atmospheric concentrations (lethal by inhalation). 9,10 We previously reported the first skin exposure to phosphine gas, 10 under exposure concentrations relevant to accidental release or hazardous material incident scenarios (50 ppm, concentration immediately dangerous to life and health (IDLH) and 1000 ppm lowest lethal concentration (LO Lo ). Skin exposed to 1000 ppm (LC Lo ) phosphine gas resulted in a flux of 1.12 mgPH 3 cm −2 h −1 across the skin, which was considered insignificant.…”

“…7 In contrast, our previous work for the fumigants sulfuryl fluoride and methyl bromide demonstrated the potential to penetrate skin within relatively brief exposure periods (30 min). 9 Furthermore, occupational exposure to methyl bromide and sulfuryl fluoride during fumigation activities have reportedly resulted in worker poisonings, in some cases specifically by the dermal route. 20,21 More work is needed to better characterize the typical exposures encountered during fumigation using cyanogen in order to make relative in-use comparisons with other common fumigants.…”

“…The findings can be applied in occupational contexts where brief skin exposures may arise, for example, during fumigation activities. The study outcomes build on the knowledge previously published assessing skin absorption of other commonly used fumigants …”