Why TSA Swabs Your Hands, Phone, Laptop, Food, Bag, Shoes And More

What TSA Is Actually Looking For

by SharonKurheg

You can breeze through TSA in minutes — or get pulled aside for a random swab test. If that’s ever happened to you, here’s what’s really going on.

Whether you’ve just spent 30 minutes in the regular TSA queues, less than 5 minutes (make that 10 minutes – TSA thinks they’re fooling someone) in the TSA PreCheck line or 3 minutes in the CLEAR area, all lines eventually lead to the security scanners.

Once you’re there, it doesn’t matter if you’ve done this a bajillion times before, or even if you haven’t and know what to do to get through the scanners quickly, you might go through the scanner and get a random alarm. Or maybe you got the dreaded SSSS (here’s what to do if you get SSSS all the time) on your boarding pass.

Either way, the TSA workers pull you aside and say you have to go through a secondary screening. It usually just involves them swabbing your hands (and/or your cell phone, laptop, food, bag, shoes, etc.), placing it in an Explosives Trace Detector (ETD) and, when given the all-clear, you’re told you can be on your merry way.

But why?

But why are they doing that? And why YOU?

The “why you” is pretty simple – it’s usually at random. Unless you’re on the super-secret list that increases your chances of getting SSSS on your boarding pass, TSA says the machines select people at random.

As for why they do it, they’re usually checking for traces of explosives. These could include:

  • NG (nitroglycerin)
  • ANFO (ammonium nitrate/fuel oil)
  • PETN (pentaerythritol tetranitrate)
  • RDX (nitramide)
  • TNT (trinitrotoluene)
  • Tetryl (trinitrophenylmethylnitramine)
  • Semtex (plastic explosives)
  • Nitrates
  • HMX (octogen)
  • GSR (gunshot residue)

(Heads up that there’s no specific list of what the TSA is looking for – that information is “Sensitive Security Information (SSI),” but the above are some of the items that potentially make things go “BOOM,” so…)

a person wearing blue gloves and putting a piece of paper into a machine

Anyway, if they decide to swab your phone, laptop, food, bag or shoes, there isn’t much you can do – hopefully, you wouldn’t have anything on those that would cause a problem when their swab goes through the ETD (or if you think they might, wipe them down beforehand). However, your hands are more likely to trigger a false positive because they can come into contact with things that have, for example, glycerin or nitrates, and there are lots of typical, everyday items that contain those chemicals. So just in case, here’s how to help avoid getting a false positive on a hand swab test.

So while the swab test might feel random, it’s actually a quick check for trace explosives — and in most cases, you’ll be on your way within seconds.

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This post first appeared on Your Mileage May Vary

1 comment

NedsKid November 23, 2024 - 7:32 pm

I once got the full treatment because I alarmed on the hand swab… at the Macon, GA airport of all places. Really crappy gas pump at the place where I refilled my rental car and I got some on my hand. And then DING DING DING. Gasoline doesn’t exactly wash off that easily.

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