What could be causing me to trip airport chemical scans?
November 21, 2022 9:58 AM   Subscribe

In the last few years, any time my hands/luggage have been chosen for the chemical swab in airports, they come back positive -- apparently for 'Tetryl'. What could be causing it?

I always assumed that it was glycerine triggering the alarms and it was a matter of some kind of cosmetics, but yesterday, they showed me the actual results and I was testing positive for Tetryl. Based on googling, that was used in explosives in the WWII era and isn't even manufactured anymore.

When I travel, I carry a fabric carry-on suitcase that's almost 30 years old, and a large purse made from recycled pop bottles. I thought maybe pop bottle recycling might involve whatever Tetryl is, but I can't find anything that suggest that it is likely.

I don't think it's environmental, because I have lived in three cities and five homes in the years that this has been happening. I have a desk job in which I type a lot of things on computers while in ordinary offices or at home.

Are there other reasons why Tetryl would be showing up on my bags / hands?

I can wash the purse and I am thinking of replacing the suitcase in hopes that will help. Any other ideas?
posted by jacquilynne to Travel & Transportation (13 answers total) 3 users marked this as a favorite
 
I found this article about TSA finding false positives, which can be caused by something as inocuous as using hand lotion with glycerin in it.
posted by Lynsey at 10:09 AM on November 21, 2022


Response by poster: It isn't glycerine I am testing positive for, but Tetryl.
posted by jacquilynne at 10:17 AM on November 21, 2022


The rapid tests are known for ... they often
display false positives and lack sensitivity
[pubs.acs.org].

An old US Army reports that nitrites and nitrates in soil could return false positives in Janowsky-type complexes (a colourimetric chemical reaction, of which these tests typically are).

Couldn't find an authoritative list of chemicals that are not explosives but will react to create Janowsky complexes. Probably for safety/ security (by obscurity) reasons.

Into guessing territory here, but it could be nitrosamines in cosmetics; diethanolamine (DEA) or triethanolamine (TEA).
posted by porpoise at 11:08 AM on November 21, 2022 [1 favorite]


Something in your life has nitrates/nitramines/etc. and it's getting on you.

Do you have plants you're regularly feeding?
posted by aramaic at 11:23 AM on November 21, 2022


Response by poster: No plants. Not even a lawn.
posted by jacquilynne at 11:31 AM on November 21, 2022


I keep testing positive for bomb stuff in the winter. One TSA agent said that using a humidifier can trigger a positive. Not sure what for specifically, but it requires all the follow ups and stuff.
posted by nixxon at 11:56 AM on November 21, 2022


Hey there, I don't think I can offer any help, but I'm wondering if you've gotten any kind of health screen. The fact that this keeps showing up (most likely) and is apparently quite toxic makes me concerned for you. I'm not sure you know it's the luggage or purse -- perhaps you have some other mechanism of exposure at home (did you ever live near Joliet or in Talladega County, Alabama?) and you have this stuff on you at other times, but you're only finding out because of TSA screening. Have you been dealing with any skin irritation or respiratory issues? Anemia?

Are you scrubbing your hands really well before you go through the line, by the way? That might help. I'd also say to wash your bag and luggage with soap.

To be clear, I am not a chemical expert or doctor, just a hyper curious librarian. Good luck!
posted by bluedaisy at 12:10 PM on November 21, 2022


Does anyone in your life have antique munitions or guns?
posted by bluedaisy at 12:16 PM on November 21, 2022


While tetryl is no longer in use, it is very much related to modern military explosives such as RDX or HMX. You may have better luck researching its other chemical name: nitramine. Don't suppose you live near a former military base?
posted by kschang at 12:18 PM on November 21, 2022


The method used for the hand swab is called ion mobility spectrometry (IMS). It's rather notoriously non-specific, so just because it says you're positive for tetryl, specifically, doesn't necessarily mean you actually have it on your skin.

The Department of Homeland Security website provides more information about the specific instrumentation used, if you feel like doing a deep dive.
posted by easy, lucky, free at 3:20 PM on November 21, 2022 [2 favorites]


Response by poster: No guns in my life of any kind for decades - that sort of thing is much rarer in Canada just generally. Maybe old military bases, since I live in Ottawa pretty of the year, but not the kind that would have had live fire exercises going on, I don't think.

It seems like there isn't going to be an easily identified source, so I will try washing the purse, replacing the suitcase and hoping for the best.
posted by jacquilynne at 7:04 AM on November 22, 2022


The issue of possible concern around old army manufacturing bases would be contaminated soil, I think. The chemical hasn't been actively (openly?) used in decades, it seems.
posted by bluedaisy at 12:52 PM on November 22, 2022


Any way you'd be coming into contact with a heart medication like nitroglycerin? Helping a relative sort their pills, or something?
posted by nouvelle-personne at 4:12 PM on November 22, 2022


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