[BeHoldAPaleHorse]

"what is TATP made of that he could have stepped in to trigger the false positive?"

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.

What are nitrates? Cheaper than day rates. :)

[Major_Risktaker]

Officials say a 50-year old Egyptian man was stopped six days ago at New York's John F. Kennedy airport. Sources say he had a suspicious pair of shoes that tested positive five times for the explosive substance TATP on the interior of his shoes between the heel and sole.

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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.

[ko_kyi]

TATP is made from acetone and hydrogen peroxide, if I understand correctly. It is cheap to make but unstable, and can blow up accidentally (like on a bench outside a stadium in Oklahoma, for example.)