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Scientists Decipher Message Left Behind in Bomb Debris With PM-Trade Center Explosion, Bjt

March 2, 1993

NEW YORK (AP) _ Secrets are being unlocked from the metal fragments, paper scraps, crystallized carbon particles and soot left by the bomb that rocked the World Trade Center.

″All of these things have a signature to the technical experts. Some of the smallest particles will speak the loudest,″ said Tom Flores, director of investigations for the Corporate Response Group, a security consulting firm.

On Monday, the area around the 100-foot wide crater had been shored up enough to allow investigators to get their closest access to ground zero. Technicians in hard hats and coveralls scraped debris into plastic bags and cardboard boxes and sent it to the city police crime laboratory for analysis.

What they are looking for are traces of a detonator, wiring, bits of paper that may have been wrapped around the explosives and microscopic bits of carbon converted into diamond-like particles by the blast.

Some of the residue was imbedded in the concrete and the cinder block walls. Cotton swabs soaked in acetone or water were used to remove the soot.

″There is nothing glamorous about the work. These are people on the hands and knees looking through the rubble, turning over every rock, to find the needle in the haystack,″ Flores said.

If the bomb was placed in a car or a van, only chunks less than an inch in diameter would remain of the vehicle.

But it, too, could be reconstructed in the same way Pan Am Flight 103 was rebuilt in a warehouse after it was blown up over Lockerbie, Scotland. And although the plane’s wreckage was strewn over the countryside, investigators found a computer chip in the detonator that they said linked the bombing to Libya.

Clues to the World Trade Center blast may also come from the heat pictures, or thermal-imaging, that will show the path taken by the explosion.

″Any explosion leaves a lot of trace behind because the chemical reactions are seldom complete. Each of the fragments has a story to tell,″ said Pers- Anders Persson, an explosives expert with the New Mexico Institute of Mining and Technology.

TNT, for example, leaves a lot of unburned carbon behind. Traces of nitrate found in the rubbled heightened speculation the bomb was made of dynamite or a mixture of fertilizer and fuel oil.

No evidence has been found to confirm the use of plastic explosives, which are favored by international terrorists. In fact, investigators have said it’s unclear whether the bombing was the work of terrorists or someone else, such as a disgruntled employee.

Because commercial explosives are regulated by the federal Bureau of Alcohol, Firearms and Tobacco, agents may be able to trace the type used back to its purchaser.

An explosion is a violent chemical reaction in which hot gas expands at tremendously high speeds. A chunk of 200 pounds of dynamite can send debris flying at over 2,000 mph and create pressures equivalent to 60,000 atmospheres, Persson said.

In the enclosed space of World Trade Center garage, the force was amplified. It hit walls and floors like a hammer and disintegrated concrete on four levels.

It knocked out the guts of the world’s second-tallest skyscraper, destroying communications and power lines.

″This was a world-class hit. I’m convinced there were specific efforts to obscure sponsorship,″ said Mike Ackerman, a former CIA agent who runs a security consulting service in Miami.

″The World Trade Center stands as a symbol of the United States, and it was a symbolic target. It was not a hit going after a particular corporation or a particular individual,″ Ackerman said. ″This bomb was intended to have impact, to cause severe dislocation. You can hardly have any attack that would have disrupted more people.″

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