Almost all explosives are nitrates. If you've been to a farm and stepped in manure or artificial fertilizer, you'll set off any decent chemical sniffer looking for nitrates.
Or step into any local Mosque and walk away with nitrates.
" Or step into any local Mosque and walk away with nitrates."
There has got to be more to this... why would they test 5 times between the heel and soul anyway... Wouldn't they test somewhere else first before they take his shoe apart?
I'm also curious as to how it resembled the shoe bomber's shoes... did it have a fuse coming out of it?
Best bet: This was an Al Quaida test to see if we would catch TATP completely encased in leather. Who knows how many tests they might do before a big attack.