IT looks like a bomb. It even smells like a bomb--enough to fool man's best friend, the pooch who's trained to sniff out explosives. But it won't explode and won't even burn decently.
So who wants a dud like that? Not your average terrorist. But the bogus bombs fabricated of nonhazardous explosives for security training and testing (NESTT) by Lawrence Livermore are piquing the interest of scores of organizations responsible for calibrating explosive-detection machines and for training humans and dogs in detecting explosive devices. In fact, Lawrence Livermore is close to completing a commercial licensing agreement for NESTT.
"We started the NESTT project about seven years ago," says John Kury, the explosives chemist who heads the project. "We had a fairly narrow need to provide a safe alternative to using actual explosives in training Livermore's canine explosives-detection teams, which have since been disbanded. As word got around about the project, we discovered a much broader need throughout the country."
When the Laboratory was training its own canine teams at the beginning of the decade, the teams had to use actual explosives and deal with the inherent dangers. Almost all the training had to take place at Site 300, the Lab's explosive test facility, where conditions certainly do not resemble those in an office building or airport. A safe substitute would permit training with a larger amount of material under far more realistic simulations.
But safety and realism aren't the only issues. Live explosives demand extra expense and care because they must be stored in bunkers or specially designed magazines and transported with special precautions. NESTT can be transported without any special precautions other than extensive documentation to prove that it is not what dogs and detection machines tell guards and police it is.
The simulated explosives made by Kury's team include stand-ins for TNT and a standard military explosive called Composition C-4 (Comp C-4), which contains RDX. By coating a layer of explosive that is a few micrometers thick on a nonreactive substance, Kury and his team produce surrogate materials that have many authentic properties of explosives, including vapor and molecular signatures. However, as long as the concentration of the parent explosive (TNT or RDX) is under approximately 8%, the materials remain nonhazardous. Kury says an early test was conducted in the Laboratory Director's conference room with about a pound of the simulated explosive--enough, if it were real, to completely destroy the room. "The dog hit it immediately," Kury says. "An animal acts differently in different environments. If you can train in real environments, there is a much better probability of a successful find."
In fact, preliminary results were so successful that larger quantities were prepared for a beta test program, which included U.S. and foreign canine units and companies that manufacture explosive-detection instruments.

Getting the Formulation Right
For the canine program, it was very important that the materials have no additional odors than those found in the parent explosive. "The method by which dogs detect explosives is not well understood," Kury says. "But we do know that they detect them by smell and never confuse glass with explosives. So it's important that the 'odor signature' of the parent explosive is maintained, and odorless silica was a natural choice for the substrate."
Kury and the team devised a formulation for dog training that uses 92% (by weight) fused silica of high purity as the substrate, onto which 8% TNT is deposited--rather like coating candy with an extremely thin layer of sugar. The formulation for the simulated Comp C-4 includes 8% RDX and 76.5% silica, along with the C-4 binder system (9.2% dioctal adipate, 2.7% polyisobutylene, and 3.6% oil).
The NESTT formulation for instrument testing is prepared by dissolving 3.3% polyisobutylene, 8.3% dioctal adipate, and 2.5% oil in pentane. That solution, along with 7.4% RDX and 78.5% cyanuric acid, is put in a high-shear mixer. The pentane is removed during mixing, and the resultant putty material is dried in an oven and molded into 2.5- by 5.0- by 30.5-centimeter bars, nearly identical to the Comp C-4 demolition bars produced by the U.S. Army. This formulation duplicates the oxygen-nitrogen ratio, effective atomic number, and density of the real explosive.
The materials have been tested in both small-scale laboratory tests and large-scale sensitivity tests, and they did not react in either the shock-sensitivity or flammability tests. Similar results were obtained by the Department of Defense when it tested mixtures of 15% or less of TNT or RDX mixed with sand.

Proof Is in the Tests
The NESTT canine test samples are formulated and packaged carefully to ensure that their odor signatures are identical to those of the parent explosives. Fused silica is also used as the packing material for shipping the samples to minimize the possibility of contamination by other organic compounds. To check the odor signature, Kury and the team use mass spectrometer analyses to verify that the vapor collected from TNT is identical to that from the NESTT TNT.
The test program has involved more than 200 handler- canine teams from U.S. and foreign agencies. More than 95% of the teams report that the canines react to the NESTT materials in the same manner they do to the parent explosive. And the 5% that did not react to the NESTT materials as they do to the parent explosive likely did so for reasons other than the authenticity of the NESTT explosive signature--e.g., the dogs were trained on "non-pure" parent explosive.
Several agencies have used only NESTT materials to train a few new canines. In all of these cases, the canines are able to detect samples of the parent explosives, TNT and C-4, reliably. These results, coupled with vapor analysis, verify that NESTT materials have authentic odor signatures.
While old Fido's nose can't be understood with scientific precision, the results of detection instruments can. So Kury's team sent samples to various organizations to see how the simulated explosives stack up against the real thing. Using nuclear quadrupole resonance, Quantum Magnetics of San Diego, California, found that the resonance of the nitrogen-14 isotope at 3.41 megahertz for RDX in NESTT was identical to that for RDX in Comp C-4, clearly indicating that the NESTT material can be used to calibrate detection machines (Figure 1).






Both TNT and RDX NESTT materials were tested by Thermedics Detection Inc. using its EGIS detection system, in which vapor and particulate samples are collected and the explosives are identified by analysis of selected decomposition products. The system detected the presence of explosive not only in the NESTT sample itself, but also on the courier's hands and the briefcase that was used to transport the sample (Figure 2). The following day, a canine being trained by the Connecticut State Police also reacted positively to the then-empty but still-contaminated briefcase.





NESTT Comp C-4 was tested on x-ray explosive-detection equipment made by Invision Technologies Inc. and VIVID Technologies Inc. Both tests gave positive results, indicating that NESTT has the same effective atomic number and density as a real explosive sample.
The beta test program demonstrated that the nonhazardous NESTT materials can benefit explosive-detection programs throughout the world. Few companies or agencies have the ability to use and store realistic quantities of explosives. With NESTT, realistic sites and scenarios can be used safely and economically to train canines that sniff out explosives and personnel who operate detection equipment.

--Sam Hunter

Key Words: canine training, nonhazardous explosives for security training and testing (NESTT), simulated explosives.

For further information contact John Kury (510) 422-6311 (kury1@llnl.gov).


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