<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by gardener:
FWIW, today's Philadelphia Inquirer reported that the explosive was found to be based on PETN (consistent with Semtex) and not RDX (consistent with C4). Both are high explosives commonly described as "plastic explosive".
And as high explosives, they need a "primary", like a blasting cap, to set them off, it can't be done with a match as others have noted.
Unclear from the news reports whether a "primary" was included in the shoes.</font>
I was watching CNBC for a bit, and the stuff this joker had in his shoes was the same stuff that was used to blow up the Pan Am flight over Lockerbie.
Also, the ticker said that somehow, the detonating devices got wet. Otherwise, they were of the opinion that the bomb would have gone off.
I'm not sure how much damage he could have done, but seeing how a boombox took down the Pan Am flight, I'm sure it would have been very difficult to get the plane down safely if he succeeded.