The Debate About Invisible Detectives
Can microscopic 'taggants' trace bombers?
But American critics aren't convinced, in part, they say, because the Swiss explosives industry is so small. Industry representatives wonder about the environmental effects of using taggants and question whether taggants in explosives would affect the purity of products made with explosive processes, like the silica powder used in silicon chips. And since explosives are used to create some building materials, they say, a variety of taggants could be present at the scene of a building bombing, which might confuse cops, not help them.
Some bombers might switch to nontagged materials; ultimately, taggants might be useful in only a handful of cases, says former FBI explosives expert Chris Ronay, now president of the Institute of Makers of Explosives. The industry is also worried about costs. ATF estimates a tagging program would hike retail costs 10 percent to 30 percent, depending on the types of explosives to be tagged--an important, open question--but record-keeping costs for manufacturers could also be significant.
Destabilizing? Perhaps the most important question, though, is whether taggants could affect the stability of explosives. That's the chief concern of the NRA in regard to black and smokeless gunpowders, which are used by millions of sportsmen. Some 28 percent of bombings involve gunpowder--usually in pipe bombs--so experts believe they'd be crucial to a taggant program. But testing by the Office of Technology Assessment did reveal potential problems when taggants were mixed with smokeless powders.
That would seem to argue for more research, and the terrorism bill signed by President Clinton in April mandates that a new study of explosive tagging be done within a year. The study will also look at whether fertilizers sometimes used in bomb making--which might be too voluminous for a tagging program--could be rendered inert, a strategy that's been pursued with limited success in Europe. An ATF team is starting the inquiry and intends to talk with industry groups and Swiss law enforcement officials.
A key question for the study panel is whether after-blast identification taggants are really obsolete and whether it makes more sense to focus on tagging explosives with vapor-producing chemicals so they could be more easily detected by sniffing machines or dogs before a bomb went off. A provision of the terrorism bill commits the United States to implementing an international treaty requiring such chemical agents in plastic explosives.
But the gap in the new ATF study is that Congress prohibited the probe from looking at taggants in black and smokeless gunpowders as a result of NRA objections. In recent weeks, the NRA has changed its position, and now says it would support a study of taggants in powders by an independent panel of scientists. A new terrorism bill passed by the House in August called for such a study, but it's unclear whether the Senate will go along before its recess next month. If not, an important part of the taggants question will remain unresolved--just as it has been for almost 20 years.
Name tags for bombs By rearranging the colored layers, a uniquely coded microtaggant is created. First developed by 3M Co., the chip is now produced by Microtrace Inc., a Minnesota firm. Microtaggant F342861930 Master code 0123456789 Taggant code example 342861930