The HLA Telepresent Control System

Not Available Secondary evaporation of chemical warfare agents released from structures onto concrete and/or soil surfaces during attacks on chemical production and storage facilities can persist for long periods relative to the lifetimes of expulsion plumes and can account for substantial agent release. The DTRA Hazard Prediction and Assessment Capability (HPAC) and engineering model Structural Expulsion Plume (STEP) include source terms for the amount of chemical agent introduced into the environment by secondary evaporation. A requirement exists for an experimental methodology to determine the amount of chemical agent introduced into the environment by secondary evaporation and for data for chemical agent simulants for the nerve agents GB, GD, and VX. The objectives of the proposed Phase I program are (1) to develop an experimental methodology for determining the rate of secondary evaporation of chemical agent simulant vapor when liquid simulant is released onto surfaces and (2) to implement the methodology for three chemical agent simulants and two surfaces (concrete and compacted soil) for several liquid deposition densities and atmospheric conditions. The methodology will be expanded to address actual chemical agents and additional chemical agent simulants and their transfer hazard during Phase II. The experimental methodology and data will be directly usable by DTRA in its source model development for the HPAC and STEP programs. The experimental methodology will be usable by other military and civilian agencies and industries in their hazardous waste management activities and for simulations of accidental releases of hazardous materials from structures or transport vehicles.