Bomb Threat Posed by Pants, Belts - This Post - External Link

Could the next airline terrorist be wearing cargo pants?

At U.S. airports, passengers are inspected, tested and searched, and in the wake of the bomb plot foiled Thursday by British police, they can't even bring a latte on board. But terrorists armed with liquid or plastic explosives can still make it onto planes because there's little technology to stop them from smuggling bombs on their bodies or in their clothes, experts say.

"When you travel, you are not protected against terrorists who bring explosives on their person or in carry-on luggage," said Hans Weber, a San Diego aviation security consultant. "It's a bigger problem than liquids."

To make detection even more challenging, there are more than 100 types of explosives, and the actual number is higher because many come in different varieties, said James O'Bryon, an aviation security consultant in Maryland who formerly served as an official in the Department of Defense.

Why can't bombs be stopped? For one thing, ordinary metal detectors are designed to detect weapons, not explosives, and X-ray machines that expose what people are carrying aren't used because of radiation concerns.

That means someone wearing cargo pants could easily smuggle in a bottle of an explosive ingredient without being detected, Weber said.

The alleged British smugglers were reportedly planning to blow up planes by using a combination of acetone and hydrogen peroxide to create a high explosive. Scientists first figured out their explosive potential in the 19th century and both are easy to obtain from chemical supply stores, although a third chemical like an acid might be needed, said Walter Rowe, professor of forensic science at the George Washington University.

The chemicals could be mixed on board in a kind of "al fresco chemistry" and then detonated using a spark generated by a battery-powered device like an iPod or cell phone, Rowe said. Or the ingredients might have blown up when mixed without an electric detonator.

The terrorists would have faced challenges, like adding water and keeping the chemicals cold, Rowe said. But not much of liquid would have been needed, perhaps not more than a few ounces of each.

Plastic explosives -- like C-4 or RDX -- are another airborne threat, and they could be carried aboard a plane easily too, Weber said.

"You could put them in slabs under your clothing, or you could wear a belt," he said. "Some people have money belts; you could have an explosive belt." And in a jacket, a packet of plastic explosives might look like a sandwich to a screener at an X-ray machine, he said.

There are also problems with the rarely used devices specifically designed to detect bombs or bomb makers.

At some airports, passengers must pass through "trace portal" chambers where puffs of air knock off molecules that are instantly tested for telltale particles left over from bomb-making.

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