WASHINGTON - The explosive powder that Umar Farouk Abdulmutallab allegedly stuffed into his underwear could have been detected in airports by "sniffer" technology or a bomb-sniffing dog, an explosives expert said Saturday.
But reports say the 23-year-old Nigerian didn't go through screening that could have signaled the presence of the explosive the FBI said was PETN, or pentaerythritol, despite traveling through two major airports.
"The PETN is readily screenable," said explosives expert James Crippin, director of the Western Forensic Law Enforcement Training Center in Pueblo, Colo.
The powerful compound, he said, is often used in plastic explosives and was found on the clothes of convicted shoe bomber Richard Reid.
It needs another explosive material to detonate it, he said.
Abdulmutallab apparently had a small amount of liquid explosive and a syringe to combine it with the PETN, something he likely tried during a 20-minute visit to the bathroom, Crippin said.
If it had been mixed right, Crippin said, "it would be one big bang" instead of the popping noises passengers heard.
The bomb's damage would largely depend on where he sat, Crippin said. CNN said he was seated above a fuel tank, near the fuselage.
It takes only a quarter-pound of PETN to destroy a car, Crippin said, so that amount or more could severely damage a plane.
The most commonly used, and relatively affordable, screening equipment - X-rays and devices to detect metal - won't pick up on powder or liquid explosives. The airports in Lagos and Amsterdam the suspect passed through appear to have used those conventional methods.
In more expensive "sniffer" technology, a traveler walks into a chamber and is hit with puffs of air that blow particles off the traveler. The device analyzes them.
Security agents could also swab passengers' clothes to test for explosives or use bomb-sniffing dogs. PETN found on the wreckage of TWA Flight 800 that crashed off Long Island was placed there earlier to test dogs.
The Transportation Security Administration also has equipment that screens checked luggage for PETN.
Dutch authorities told The Wall Street Journal it is difficult to detect all dangerous objects being brought on board a plane, particularly those that can evade common security technology, such as metal detectors.