On Thu, 16 May 2013 01:08:11 -0500, repairs wrote:

Somehow this does not seem safe. If the temperature had been higher,
I'm afraid it would have blown up. There needs to be some sort of
pressure relief on them, or KABOOM!

While I agree with you that they blow up like a balloon, which
makes them tip over easily, I don't think they'll ever actually
explode from the 13 psi above atmospheric vapor pressure inside.

If you didn't see it, here's a picture I had posted of my 5-gallon
Blitz gasoline can where I took two cans from the shaded shed, and
put one in the sun, and the other next to it, in the shade, for
ten minutes ... look what happened:

http://www2.picturepush.com/photo/a/...g/13045875.jpg