I carry a couple of the green bottles in my rear closet to run my Coleman, and for emergency reserve. I have an extend a stay with adapter that can use these. I figure there are 40 or 50 of these things in the supermarket, and if they were that dangerous they probably would not allow that. The things are everywhere too. More shops sells these green jems than I can think of. I had heard of these things leaking when they are refilled, and of course the manufacture does not recommend this. These are meant as disposable, one-time use canisters. However, if you really want an extra measure of insurance, I have seen on Amazon some brass screw tops for these that have a rubber seal. I think they are about seven or eight dollars a piece, and don't think they would be a bad idea for little extra insurance. I have never seen a new canister leak in 30 years, but I certainly have seen refilled ones leak. I think we need to remember again, that these things are meant to be disposable. The more you use them, the more likely they are to leak. 

Probably a good time to mention too that we should all have carbon monoxide and propane detectors on board, which reminds me I need to replace mine this year! 

Troy