Although in a field test five days after the crash it also was detected on the right wing near where it meets the fuselage, that test was not confirmed in Washington. Still, the PETN find is considered by many outside experts to be more than a coincidence. PETN itself, a white or tannish granular material, is considered quite volatile in its initial state, but does stablize when mixed with other substances into a malleable material, commonly known as plastic explosives, not unlike modeling clay. In granular form, PETN is also one of the more easily detonated and sensitive explosives, one expert said. If you were to put just a pinch of the white powder on an anvil and hit it with a hammer, the resulting blast would break the hammer and send metal fragments flying.
Miners use the stuff as a primer to help blast away rock.
Building demolition experts use it to help down structures. It's also used for metal cutting and a type of welding. Still, the residue can hang around for a while. Walter Korsgaard, a former air crash investigator who worked on the Lockerbie blast, recalled an incident several years ago when bomb-sniffing dogs responded to a baggage container that had been used to transport explosives at least six months earlier. And it doesn't take much PETN to set off testing devices, as Jimmie Oxley, an FBI explosives consultant found out.