Performance of an emerging all-weather decontamination solution against nerve and mustard agent simulants at subfreezing temperatures

Solutions for decontaminating chemical and biological agents should be able to perform in all climatic conditions, including subfreezing temperatures. Below 0 °C, aqueous-based decontamination solutions or their components can freeze, rendering them inactive and difficult to handle. Moreover, rates of neutralization will be dramatically slower than at normal room temperature. In a series of replicated laboratory studies, we quantified the efficacy of an emerging decontamination solution, DECON Green, against the VX nerve-agent simulant bis-(2-ethyl hexyl) phosphite and the HD mustard agent simulant 2-chloroethyl phenyl sulfide. The efficacy of the DECON Green formulations was tested at 4, − 5 and − 15 °C using both contact-hazard assessments and mass balance approaches. Contact-hazard assessments simulated the transfer of simulant to skin. The mass balance approach addressed the fate of simulant by quantifying recovery following each step of the decontamination process. Two formulations of DECON Green were investigated: the “standard” formulation, New DECON Green, and the “cold weather” formulation, CA2WT. Simulants were spread on chemical-agent-resistant-coating-treated aluminum disks (CARC coupons). The CARC coupons were subsequently decontaminated using standard U.S. Army operating procedures. At all temperatures investigated, sequential contact hazards of the simulant were three to four times lower in concentration for the mustard simulant and nerve-agent simulant, respectively, following the application of DECON Green and washing than without DECON Green or without washing. The mass balance data showed that washing with a propylene glycol:H2O solution was an important part of the decontamination process. DECON Green both degraded the simulants and increased the simulants removed during washing. These findings indicate that at both − 5 and − 15 °C, temperatures at which water-based procedures would be problematic, the cold-formula DECON Green plus washing with propylene glycol:H2O was effective at reducing surface contact hazards from the two chemical agent simulants.