All chemical weapon demilitarization technologies generate large amounts of potentially agent-contaminated secondary wastes as well as contaminated equipment, machinery, and plant structural elements. Chemical agent contamination levels for secondary waste, process machinery, and demilitarization equipment (tools, respirators, instruments, etc.) resulting from agent and energetics destruction processes have to be determined in order to develop safe decontamination strategies and/or disposal options. Furthermore, demilitarization plant structural elements may need to be decontaminated for maintenance activities required during disposal operations and agent changeover breaks in plant operations and during plant closure.
CMA has developed methods for determining whether waste materials, equipment, machinery, and even structural elements are contaminated by chemical agents. These methods generally involve (1) isolating the objects of interest in some sort of enclosure and (2) after a specified equilibration time, measuring vaporized agent concentrations in the enclosure’s headspace. In other cases, wipe samples of surfaces can be obtained and solvents may be used to extract chemical agent contaminants from wipe samples or waste stream materials and then analyzed with chromatographic techniques. These proven techniques are available and are planned for use in the two new ACWA demilitarization plants now being built.
While effective, these traditional methods can be time consuming and have to be repeated if initial decontamination efforts are not successful. A recent review, focused on technologies for quantifying agent vapor concentrations in CMA demilitarization facilities (NRC, 2005a), noted the potential of then newly developed ambient surface ionization mass spectrometry techniques to provide real-time measurements of chemical agent contamination on surfaces. Ambient ionization mass spectrometry involves sampling and ionization of chemical species in their native environment without, or with minimal, sample preparation. Objects sampled are usually solids, and the experiment is typically done at atmospheric pressure, with total analysis times on the order of a few seconds. Subsequent development of a wide range of ambient surface ionization techniques with mass spectrometric detection has been rapid and impressive. Significant improvements in sensitivity, response time, portability, and reliability have been demonstrated, and an increasing number of systems are or will soon be commercially available.
This study is focused on whether ambient surface ionization analytical techniques are sufficiently sensitive, specific, rapid, robust, and available to supplement current Army methods for screening materials, equipment, and structural elements for agent contamination. Considerable time and effort are spent characterizing and decontaminating secondary waste, process machinery, and equipment during both disposal operations and plant closure; this significantly extends the time needed for safe and effective chemical weapons destruction and prolongs plant closure. If robust, portable, real-time surface agent contamination analytical instrumentation is available and can shorten the time and effort required for tasks not directly contributing to chemical weapons destruction, they may be well worth deploying at the two new ACWA demilitarization plants.