Me bad for clogging the thread, but technically speaking (tinfoil hat time) , that should read methane although I believe there is some hydrogen in there as well. In keeping with the technical theme.... There were some fellows that introduced a relatively small amount of methane into the carb of a running P&W radial. They were surprised how quickly the engine died. They were researching the disappearance of aircraft in the Bermuda Triangle and were speculating a cloud of methane belched out of the ocean floor. No idea why I have that rattling around in my head.