Characterization of an odor permeable membrane device for the storage of explosives and use as canine training aids

Abstract

The storage and use of explosives is regulated at the state and federal level, with a particular focus on physical security and rigorous accounting of the explosive inventory. For those working with explosives for the training and testing of explosive‐detecting canines, cross‐contamination is an important concern. Hence, explosives intended for use with canine teams must be placed into secondary storage containers that are new, clean, and airtight. A variety of containers meet these requirements and include screw‐top glass jars (e.g., mason jars). However, an additional need from the explosive‐detecting canine community is secondary containers that can also be used as training aids whereby the volatiles emitted by explosives are emitted in a predictable and stable manner. Currently, a generally accepted method for the storage of explosives and controlled emission of explosive vapor for canine detection does not exist. Ideally, such containers should allow odor to escape from the training aid but block external contaminates such as particulates or other volatiles. One method in use places the explosive inside a permeable cotton bag when in use for training and then stores the cotton bag inside an impermeable nylon bag for long‐term storage. This paper describes the testing of an odor permeable membrane device (OPMD) as a new way to store and deploy training aids. We measured the evaporation rate and flux of various liquid explosives and volatile compounds that have been identified in the headspace of actual explosives. OPMDs were used in addition to traditional storage containers to monitor the contamination and degradation of 14 explosives used as canine training aids. Explosives were stored individually using traditional storage bags or inside an OPMD at two locations, one of which actively used the training aids. Samples from each storage type at both locations were collected at 0, 3, 6, and 9 months and analyzed using Fourier Transform Infrared (FTIR) Spectroscopy and Gas Chromatography–Mass Spectrometry (GC–MS) with Solid‐Phase Microextraction (SPME). FTIR analyses showed no signs of degradation. GC–MS identified cross‐contamination from ethylene glycol dinitrate (EGDN) and/or 2,3‐dimethyl‐2,3‐dinitrobutane (DMNB) across almost all samples regardless of storage condition. The contamination was found to be higher among training aids that were stored in traditional ways and that were in active use by canine teams.

Screening of volatiles from explosive initiators and plastic‐bonded explosives (PBX) using headspace solid‐phase microextraction coupled with gas chromatography – mass spectrometry (SPME/GC–MS)

“…Safety fuse was also analyzed and confirmed in a previous study, with the most prominent volatile being sulfur, which is a component of the black powder filling in the fuse [14] (Figure 5).…”

Evaluation of canine training aids containment for homemade explosive and components by headspace analysis and canine testing

“…The device has been tested for safe containment of hazardous components passing drop, altitude, high and low temperatures, vibration, and crush tests (unpublished data). Tests have shown that volatile compounds from the material within the TADD are freely able to pass through the membrane for detection in the headspace without any physical material escaping or contaminating the outside of the device [6, 7]. Previous research has tested explosive‐related volatile organic compounds (VOCs) through the membrane to include nitromethane, toluene, nitromethane, 1‐nitropropane, and r‐limonene, and found that these compounds readily evaporated from the TADD with and without the membrane, though the presence of the TADD membrane decreased the flux of the vaporous components by several odors of magnitude [7].…”