At 10:57 AM 11/17/01 -0800, Sandy Sandfort wrote:
Airport chemical "sniffers" apparently look for the signature of nitrogen compounds, not "explosives," per se. I've often wondered how many weekend gardeners have gotten hassled and delayed because of trace amounts of ammonia-based fertilizers on their person and effects. If you plan to fly, be sure to wash your hands thoroughly before heading out for the airport if you have been shoot, gardening or house cleaning.
I've wondered about that too; airport sniffers must have encountered Miracle Gro and angina nitro during the early days, measuring a false alarm rate. Shooting is scary; you could contaminate your car driving back from the range, then contaminate your travel gear. The explosives expert in one of the older terror trial docs on cryptome says things suggesting that a few washes will remove traces. (And contaminate clothes washed with them.) I once checked out the screen on a sniffer, and they list "nitrates" as a category. I suppose having PETN (another category) detected on your laptop would be harder to explain :-)