Originally Posted by
I_Can_Fly_US_Airways
Did a firearms training course outside Las Vegas 2 years ago. Fired at least 400 rounds of ammunition (.45ACP) that day. Drove to McCarren Airport right after finishing the course in order to make a 7pm flight so no time to shower, change clothes etc.
Going thru TSA, I get swapped. My first thought is "Uh-oh", not good )-:
So what does the swap strip detect...NOTHING! If ever it should have registered as positive, I would think it would have been that day.
Just because the swab didn't detect the GSR on you doesn't mean it detects "NOTHING."
Although the exact compounds the ETD swab detects are, naturally, SSI, the general consensus is that it looks for nitrates and glycerine. One would think that GSR would have some nitrates in it, since firearms propellants typically include a nitrate component. However, it's possible that the ETD looks for other compounds instead, to reduce false positives brought about by exposure to innocuous nitrate-bearing products like GSR, or fertilizer, or even fireworks.
All that being said, however, I am contemptuous of the entire current ETD process, which is so dependent on individual TSOs who have no grasp whatsoever of the concept of "cross contamination" preventing cross-contamination. The test itself may be completely valid, but since it's being done under field conditions by personnel who can only laughingly be called "trained" or "competent", the validity of the test in any specific case is highly suspect. Add in improper maintenance of the machinery, and the whole test is being ludicrously tainted.