Comment by metalman

no propane burners. propane freezes solid at minus 60°, and you need heaters to get any flow long before it gets that cold, to the point that you can set propane out in a bucket, which I have some experience with in useing it, to supper cool transmission shafts, so that they shrink, and press fit bearings slip right on. so yes they have propane, but they use it in other, less well known ways.