ETD machines can be programmed to detect just about anything, not just explosives. Here are some of the things that they can be programmed for that have an application useful to the TSA.
RDX (cyclotrimethylenetrinitramine)
PETN (Pentaerythritol tetranitrate)
TATP (triacetone triperoxide)
HMTD (Hexamethylene triperoxide diamine)
SEMTEX (Contains for RDX and PETN)
NITRO (nitroglycerine)
TNT (Trinitrotoluene)
HMX (cyclotetramethylene-tetranitramine)
The ETD systems are designed to detect trace elements that are contained in explosives using (most commonly) Ion mobility spectrometry, electron capture detection, electrochemistry, and olfaction .
If one looks on the component listing of the various products they buy for personal use you may indeed find some of these base chemicals listed, which is why the ETD’s may occasionally alarm on your hand lotion or whatever. These are not “false positives” but actual detection of the chemicals they were designed to detect. ETD machines cannot perform a complete chemical breakdown of the samples provided, they are just not designed to do that. They can only tell us when they detect what they are programmed to detect. TSO’s are not chemists and anyone who expects us to be has some serious problems with reality. If an alarm happens they we need to find out why, it’s as simple as that. That means a search, since lie detectors are somewhat unreliable.
TSA is currently testing several different types of ETD based systems such as FIDO (
http://en.wikipedia.org/wiki/Fido_Explosives_Detector), the SABRE 2000, plus other technologies like the BLS (Bottle Liquid Scanner), SSD (Shoe Scanning Device), and many more.
Yes, its not really all that uncommon. Explosives are used not just by terrorists and the military but by quite a few different commercial concerns and police agencies. Hence the reason we dont make a big deal out of it, its about like finding a 1955 penny in a bucket full of pennies.