In Australia at least, I am aware of Acetylene cylinders that were a
hazard in the heat many years ago. The problem wasn't the cylinders
themselves but a fuseable plug mounted on the top section - I guess
it was a safety valve in case of fire or overheating.
I was doing a basic firefighting subject in the Royal Australian Air
Force when one of our instructors raised the subject and showed some
photo's. The problem cylinders were mounted in small external
enclosures on the outside of sheds in an area of Australia that
rarely gets too hot. Several of these enclosures were painted in
dark colours and some were actually painted black. A prolonged heat
wave in an extremely hot summer caused the temperatures to rise above
the fusable plugs temperature rating and caused a number of them to
I don't know if they put higher temperature plugs in but the fire
authorities did suggest light coloured enclosures.
Sunny Queensland, Australia