Wow! My daughter just went camping and took our Coleman propane stove. When we were testing it before the trip, I noticed that the bottle of gas did not completely seal when we removed it from the stove. A very faint hiss. I said "No way are you taking this cannister - go buy some new ones." After hearing about this tragedy, I'm sure glad I said that to her now. I put the cannister out about 60 feet from the house, up in a tree (so the dogs wouldn't get to it), and planned for it to eventually leak itself out. But a week later it's still full and the faint hiss has stopped. So it must have finally sealed. I'm not sure how to get rid of this thing. I think I'll hook it up to the Coleman and run both burners on high (lit, of course!) until it empties. This will be done way far out from the house and any people.