TATP is used in a a toy pyrotechnic device known as a "torpedo", consisting of a twist of paper containing gravel coated with a small quantity of TATP. These are thrown onto the ground, producing a satisfying bang. These "torpedoes" are available legally in states that allow firework sales such as Louisiana and Wisconsin. They are sold illegally in the "Chinatown" districts of San Francisco and Los Angeles (California). AKA, Poppers........
The terrorists must have beem watching old "McGyver" re-runs.