I also have to question though, at what temperature does the paint reaction take place? I mean, unless you believe it was sabotage and somebody held a torch to the Hindenburg; which happens first. The skin "melts" enough so the hydrogen can escape and ignite with the oxygen with a lower temperature flame, or the reaction of the paint starts? Also, how sensitive is the paint to spark ignition, as that is where most people tend to think what caused the initial ignition. As it was landing when it happens, and when dirigibles land they must exhaust gas, so the hydrogen was being mixed with the air, at that point.
So which is more likely to have started it, could have been easily answered though.