I am wondering if there are any materials that are allowed by the TSA regulations concerning checked-in luggage that might react to X-rays. This question would fit both Travel and Chemistry. However, Travel would likely know what is allowed by the TSA, but not how these materials react to X-rays, while Chemistry would likely know what materials react to X-rays, but not necessarily if those materials are allowed in checked-in luggage.

I'm not sure on which one I should ask this. It's purely for curiosity reasons, BTW. I have no intentions whatsoever to abuse the information from the answers. At most, I might choose to pack a different item to avoid any unpleasantness.

  • It's an interesting question. Fruitcake, for example, is widely reputed to have the same X-ray density as plastic explosive.
    – Mark
    Commented Sep 22, 2015 at 23:46

2 Answers 2


I would advise asking two (or more) separate questions. Ask about how the chemical(s) you're concerned with react to x-rays on Chemistry and ask about whether those chemicals are banned by TSA here on Travel.

Before posting the latter question, you might also try checking TSA's website to see if they already provide a clear answer regarding the chemicals in question.

Even if TSA's website does say that the chemical(s) you're concerned about are allowed, it still might not be a bad idea to ask about traveling with them here, though, as just because something isn't explicitly banned by TSA policy doesn't necessarily mean that any given TSA agent will allow you through with it. They don't all have every detail of the policies memorized.


Coming from chemistry.SE:

  • It could be considered on-topic to ask if and how material X reacts under X-ray irradiation. You would have to be careful to phrase it in a way that makes the question not sound like a homework question.

  • Asking whether and how a list of materials react under X-ray irradiation would be closed as too broad.

  • Likewise if you just asked which materials.

    The reasoning for the above is that we cannot possibly know all sorts of different materials and how they can or cannot react under given conditions. Narrow it down to one and you’re good.

Of course, chemistry would be of no help to you in determining whether or not something is allowed in checked luggage; that is what this site here is for.

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