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Revista de Prensa: Noticias

Viernes 11 de agosto de 2006

Liquid Threat Is Hard to Detect

Despite knowing for years that liquid explosives posed a threat to airline safety, security agencies have made little progress in deploying technology that could help defend against such attacks, security experts say.


 Since September 2001, the federal government has hired tens of thousands of government screeners and upgraded its metal detectors and X-ray machines. But most of the equipment is still oriented toward preventing a metallic gun or other easily identifiable weapon from being carried aboard; it cannot distinguish shampoo from an explosive.

Cathleen A. Berrick, director of the Government Accountability Office’s homeland security and justice division, told a Senate committee in February 2005 that the Transportation Security Administration, part of the Department of Homeland Security, redirected more than half of the $110 million it had for research and development in 2003 to pay for personnel costs of screeners, delaying research in areas including detecting liquid explosives. It has continued to redirect some research and development money, she said Thursday.

“They’d identified it as a vulnerability, they knew it was there, and they’d taken some steps to address it,’’ Ms. Berrick said.

In 1995, a plot to bomb 12 American jumbo jets over the Pacific with a liquid explosive was discovered when the bomb makers accidentally set fire to their laboratory in Manila. Ramzi Ahmed Yousef, who was also involved in the World Trade Center truck bombing in 1993, was convicted in that case.

James Jay Carafano, senior fellow at Heritage Foundation in Washington and an expert on domestic security, said that in the last year, officials at the highest levels of the department recognized the seriousness of the threat posed by liquid explosives and had been pushing aggressively to introduce equipment that could help.

But no such devices are ready to be rolled out.

“This is not a case of them being caught like a deer in the headlights and saying, ‘Oh my God we never expected this,’ ” Mr. Carafano said. “In fact they expected this threat.”

The overnight ban on carrying liquids aboard flights that was imposed Thursday was about the only step immediately available. The ban was only in use for flights originating in this country or Britain; passengers can still carry liquids on American planes flying here from other countries.

The president of the passenger airlines’ trade association, James May of the Air Transport Association, said: “I would like to see them have a much larger R&D budget. As the technology of terrorism gets more sophisticated, we have to be more sophisticated.’’

The department has been moving ahead with the installation of one proven technology, so-called puffer machines, which blow a small amount of air on passengers to look for traces of explosives. To date, the machines have been installed at about 30 airports around the United States, including in New York and Washington.

But these devices may not sound an alarm if a terrorist has been extremely careful in preparing the liquid explosive, meaning no traces are left on the container or the person or bag carrying it.

And once on board, mixing the explosives would be “as easy as mixing a gin and tonic, if you have the right stuff,’’ said Paul Worsey, an explosives expert and professor of engineering at the University of Missouri at Rolla.

Most liquid explosives would require a detonator, but a music player or other hand-held passenger gadget has sufficient electrical energy to do that, experts say.

Without appropriate detection technology, the basic tool for now is big plastic garbage bags, which screeners were using to accept containers of shampoo, hand lotion and beverages that the Transportation Security Administration said were being “voluntarily surrendered” by people who packed their bags on Wednesday night, when those items were considered innocuous, and arrived at security checkpoints on Thursday morning, when they were considered “threat items.” Security officials also rescreened passengers at the gate at some airports.

Finding the containers in carry-on bags is also not foolproof.

“Pulling out liquid containers is a fairly easy step,” said Steven V. Lancaster, vice president of Guardian Technologies, of Herndon, Va., which makes detection equipment.

But that presumes that the container was in a bag that went through an X-ray machine. The portals that screen people at the airports only detect metal. Hence being sure that there are no liquids will require more pat-downs of passengers.

Mr. Carafano said Homeland Security did at least get an interim program into place quickly in reaction to the London plot, and one that should create, at least in the United States, a decent level of deterrence.

“The terrorist threat has already plummeted significantly,” he said, “as the number of people who can do this is probably relatively small and we have had these arrests. And you have a much heightened awareness. Terrorists like predictability and that is gone now.”

Homeland Security, while elevating the threat level for the first time to “red” or severe, announced that the highest level of alert applied only to the aviation sector, avoiding the kind of broad-brush announcements that were common during the administration of Tom Ridge, the first Homeland Security secretary.

There are technologies that may do the job — without simply throwing all liquids into the trash.

A. Louis Parker, the president and chief executive of General Electric’s security division, said, “I’m 100 percent sure that if it’s a known explosive, we could detect it with today’s technology.’’ His company opened a lab in San Francisco last December called the Checkpoint of the Future to explore new techniques.

Guardian Technologies already makes software that analyzes the images produced by X-ray machines. Mr. Lancaster said that the Transportation Security Administration would begin testing, possibly next week, a new computer program that looks at the X-ray image pixel by pixel, far more carefully than the human eye could. The software can be set to sound an alarm when a specified number of pixels show a liquid (or solid) with a density that is characteristic of an explosive.

Another vendor, Rapiscan Systems, a subsidiary of OSI Systems, which makes metal detectors and other equipment already used at checkpoints, is developing a liquids detector for the Department of Defense, according to Peter A. Kant, vice president of governmental affairs. The device, about the size of a newspaper vending box, bombards an object with subatomic particles called neutrons. Atoms hit by the neutrons give off a gamma ray characteristic of each atom. The machine can sense what part of a briefcase or other small object is giving off gamma rays characteristic of explosives, he said.

That system is still under development.

Rapiscan is also developing a technology called quadropole resonance, that can be added to existing X-ray machines. An object is bombarded by radio-frequency energy. Objects being scanned resonate in a way that is particular to their chemical make-up, so individual chemicals can be scanned for. “We’re going to tell it’s not shampoo, suntan lotion, wine or water,” Mr. Kant said.

The Transportation Security Administration evaluated the technology early this year. But it has not been tested for looking for liquids that are individual ingredients of explosives.

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