And McVeigh used ammonium nitrate which wasn't tested, and as a highly soluable (in fact deliquescent) inorganic it probably won't persist like a nitrated organic. Also common as dirt in agville.
He also added nitromethane to the mix, obtained through the common auto racing channels.
Nothing like dropping a little Miracle Gro in the men's room at the airport to keep the mass spec goon awake :-)
Note that if hair is collected they've got your DNA too.
Wonder if screeners will insist on taking a sample of hair from other body areas if you are bald?
steve
