Tools to Fight the Terrorist Threat

Abstract

Chemical, biological, radiological, nuclear, and explosives (CBRNE) terrorist threats put law enforcement and soldiers at risk both at home and abroad. Law enforcement and soldiers must be provided with tools and knowledge to stay ahead of the capabilities of terrorists. Hexamethylene Triperoxide Diamine (HMTD) is a homemade explosive easily synthesized from hexamine, citric acid, and hydrogen peroxide. Although HMTD is very sensitive and prone to stability problems, it has a history of terrorists use, such as in the London bombing of 2005. Because law enforcement personnel must handle this material with no guarantee of purity nor indication of additives, for the sake of safety, knowledge of the stability and reactivity of HMTD was expanded in order to make handling safer. Differential scanning calorimetry was utilized to screen the compatibility of HMTD with various additives. It was found that water and weak acids, such as citric acid, destabilize HMTD. Gas chromatography / mass spectrometry (GC/MS) was employed to characterize both headspace gases (e.g. trimethylamine and dimethylformamide) and condensed phase decomposition products. Monitoring the decomposition of HMTD at room temperature and with gentle heating (60 ⁰C) under various levels of humidity proved that humidity plays a major role in the kinetics of HMTD decomposition. Liquid chromatography / mass spectrometry was helpful for identification of condensed phase decomposition products and monitoring isotopic labeling studies. Through a labeling study with equimolar 15N and 14N hexamine during the synthesis of HMTD, it was found that hexamine dissociates before the formation of HMTD. There is currently a need for specialized pyrotechnic materials to combat the threat of biological weapons. Materials have been characterized and will be chosen based on their potential to produce heat and iodine to kill spore-forming bacteria (e.g. anthrax). One formulation, already proven to kill anthrax simulants, is diiodine pentoxide with aluminum; however, it suffers from poor stability and storage problems. The heat and iodine output from this mixture and candidate replacement mixtures were measured with bomb calorimetry and extraction and analysis of iodine by UV-Vis spectroscopy. Of the mixtures analyzed, calcium iodate and aluminum was found to be the highest producer of iodine gas. The heat output of this mixture and others can be increased by adding more fuel, with the cost of some iodine produced. Products of combustion were analyzed by thermal analysis, XPS, XRD, and LC/MS. Evidence was collected supporting the formation of metal iodides and metal oxides. One key