Firefighter carrying a burning gas tank - GIF

[Frank S]

Well, this isn't any ol' fire crew. The carrier is in a true fire suit of aluminized fabric like Nomex. I'm a little surprised they were clustered around it, and fact it was carried out, but something made it clear there was not going to be any significant pressure generated in the bottle or ignition of contents within, just escaping vapors.
Are not fuel cylinders fitted with fusible plugs, and asbestos matting inside just for this eventuality?
Cue Frank S...........

The kind generally associated with BBQ grills and RVs are, which is evident by the triangle shaped valve knob. 100 lb cylinders such as the one being carried can still have the old-style valves and can be refilled these might or might or might not have a venting valve to relieve the pressure and contents but nothing to prevent escaping vapors due to heat. or fire, better to bleed off the pressure than for it to build to explosive stage.
Remember vapors are what burn. you can literally put out a gasoline fire with a large enough dousing of gasoline if done rapidly enough to starve the fire completely of oxygen