FBI Confirms Explosive Found in TWA Debris

Federal law enforcement officials announced publicly Friday that “microscopic explosive traces” have been found on part of the airplane wreckage of Trans World Airlines Flight 800.

But they cautioned that there is not enough of the residue, which is still being examined by forensic experts, to tell investigators how or why the jumbo jet carrying 230 people exploded last month in the skies off Long Island.

“Based on the evidence to date,” said James K. Kallstrom, head of the FBI’s field office in New York, “investigators cannot conclude whether this tragedy was the result of a criminal act.”

Kallstrom declined to provide details on what kind of residue was found. But other federal law enforcement sources, speaking anonymously, said that it was traces of PETN, a potent plastic explosive component that has been used in the past both in airplane bombs and surface-to-air missiles.

They described the amount of PETN uncovered in the FBI’s Washington laboratory as no larger than a “speckle.” They said it was found on a piece of seating material on the right side of the plane’s middle passenger compartment between Rows 17 and 28.

That area of the plane--the central fuselage--has become for investigators the most likely spot where the explosion originated, whether from a bomb, a missile strike or a mechanical failure.

Appearing at a hastily called news briefing to refute rumors that the FBI now considers the disaster a criminal act, Kallstrom departed from his normally low-key delivery to read a carefully written statement that he said was intended to tell the public exactly where the investigation stands.

“As a result of scientific analysis conducted by federal examiners, microscopic explosive traces of unknown origin have been found relating to TWA Flight 800,” he said.

“However, based on all of the scientific and forensic evidence analyzed to date, we cannot conclude that TWA Flight 800 crashed as a result of an explosive device,” Kallstrom continued. “Forensic experts outside the government, consulted by the FBI, agree that the detection of the microscopic explosive traces alone does not allow the conclusion that TWA Flight 800 crashed as a result of an explosive device.”

He said that more corroborative evidence must be found, none of which has yet been detected after more than 60% of the plane’s wreckage has been recovered from the ocean floor.

“For example,” he said, “physical damage or patterns characteristic of a detonation would need to be available in addition to confirmed explosives as trace findings before a positive conclusion of an explosive device could be made.”

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That description compares to those of the two law enforcement sources, who cautioned that PETN could have come from the clothing of a hunter, soldier or quarry worker--indeed, from anyone who might have come in contact for whatever reason with explosive material before boarding the plane.

They said that it also could have come from Navy equipment used to hoist the wreckage out of the water and transport it back to land. But Rear Adm. Edward Kristensen, who is overseeing the Navy salvage operation, said there were no residues on either of two large Navy ships “that could have contaminated anything.”

In addition, the sources said it is perplexing that only a small piece of PETN was found, because a bomb or missile explosion should have left behind more and larger splotches of the explosive material.

“Any time you find minute traces of chemical, you can’t jump to conclusions,” said one of the sources, a senior law enforcement official. “There are a lot of things that could have contaminated the evidence.”

The 747 jetliner exploded shortly after takeoff as it climbed past 13,000 feet on the evening of July 17. All but 20 of the victims have been recovered.

Explaining that the investigation will go forward, Kallstrom said: “We need to assure the American people, the families of the victims, the traveling public, that we know exactly what happened.”

Experts said that explosives made from chemicals like PETN (short for pentaerythritol tetranitrate) are attractive to terrorists for several reasons. They create a larger explosion than a similar amount of nitroglycerin or TNT. They are safer to transport because they are not easily detonated. And they give off fewer vapors, making them difficult to detect.

The material generally cannot be detected by airport inspection devices, particularly those in the United States that do not have the more elaborate high-tech systems found in Europe.

Plastic explosives were developed during World War II. Today, in the right hands, they can be made to look like bricks, shoe leather or even Silly Putty.

“In U.S. airports, this could be carried on in your luggage, in your coat pocket, even in your hand,” said Marty Salfen, a senior vice president of the International Airline Passengers Assn.

He said that the TWA disaster has put more pressure on the Federal Aviation Administration to mandate tougher airport inspections.

“In this country,” he said, “we have 750 million bags checked each year. And that’s just domestically. Start thinking about how you are going to better scan all that luggage with new technology.”

Vince Cannistraro, a former CIA counterintelligence operations chief and lead CIA investigator in the bombing of Pan American Airways Flight 103 in 1988 over Lockerbie, Scotland, said of PETN: “A small quantity is all that would be needed--a few pounds--to blow up a 747.

“You want it in a place where it is central,” he added. “Pan Am was a small bomb. It had to go through a suitcase, cargo bin, luggage hold and exterior, and it was only about a pound and a quarter of high explosive.”

In the case of the TWA flight, he said, someone “could take it in on hand-carry [luggage] and assemble the bomb on board, then put it under your seat.”

“A prime place might have been to stick it in a life jacket [under a seat],” he said. “No one checks those things. And it’s not visible. It didn’t need to be a big bomb, so it could fit there. Then the plane takes off and it hits the appointed time and it blows.”

Investigators have said there is strong evidence of a fiery explosion in the center fuel tank, which underlies a portion of the passenger cabin directly ahead of the wings. That evidence includes bits of charred, twisted metal from the fuel tank area.

Investigators believe it was the explosion of the fuel tank, possibly triggered by a bomb blast, that actually brought the plane down.

The latest twists in the highly complex investigation underscore problems that have cropped up between the two lead agencies, the FBI and the National Transportation Safety Board.

NTSB Vice Chairman Robert Francis, who is leading his agency’s review of the crash, told reporters Friday morning that he knew nothing of any bomb residue found in the plane wreckage.

Then Friday afternoon, Francis said he learned of the finding from Kallstrom as soon as Kallstrom found out. But Kallstrom indicated that he had known of the residue for some time.

Further complicating matters is that it appears some members of the two federal agencies, after five weeks of working together, are beginning to wear on one another.

Some NTSB personnel have complained privately that Francis has let the leadership of the investigation slip away to the FBI.

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“He’s not been representing our people the way he should,” said one NTSB official who asked not to be identified. “He’s not been sticking up for them.”

Others have complained that Francis--by now a familiar face on national television--has been skipping some of the nightly progress meetings at which his investigators discuss daily findings.

Francis, who has been based near the crash site in Smithtown and who has spent much of his time on recovery ships and at the debris reconstruction site in nearby Calverton, N.Y., was asked this week how he keeps tabs on the investigative developments in Washington.

“I’m not that interested in that,” he replied.

There are further complications.

Kallstrom’s FBI agents are primarily interested in assembling evidence as quickly as possible that could be used to obtain an arrest or arrests and criminal conviction. Francis’ experts, however, prefer a slower approach aimed ultimately at developing better ways to make flying safer.

There is also the disparity in resources. The FBI, with a vast budget, has been able to commit hundreds of agents to the case. The NTSB, one of the smallest and least-funded agencies in Washington, has only a few dozen people working on the investigation.

Times staff writer Robin Wright in Washington contributed to this story.

BACKGROUND

PETN, reportedly found on TWA Flight 800 wreckage, is a favorite explosive of terrorists because it is powerful, easily molded and escapes X-ray detection. The white, crystalline substance is generally mixed with other explosives and materials like latex to make it malleable. Legitimate uses include commercial blasting, and anyone with a blasting permit can get PETN and the materials it is used with for about $20 a pound.