Once heading to the Bahamas, I put my PFD with (2) canisters "not installed" in my carry on. I saw the Dulles International TSA screener pause looking at my bag. He called another officer over and they both told me my canisters would not be permitted. I had fortunately printed out TSA's published policy regarding these and asked that they show their supervisor for clarification. I was allowed to proceed on the flight with my canisters.
That was a few years ago, google their current policy to see if things have changed, if still permitted take it with you.
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