"No kidding--with all the explosives in that place, it's a wonder they had a place to sleep or hang their clothes!"
There's also quite a distinct odor, when "cooking" either TATP or ANFO. Stinks as bad as a meth lab, in my understanding. Cheema knew. No way around it.
A link on the distinct odor or "funny smell" of TATP, known as "Mother Of Satan" in certain circles:
http://www.classicalvalues.com/archives/002914.html