Is Asitone a Cause of Human Combustion?

spontaneous human combustion is that it seems to happen spontaneously with no conventional fire source. Even if asitone was a contributing factor, you still need an ignition source for the fire. One sal that's been made to explain some of the cases is lightning. But an ordinary lightning strike on a house would damage more than just the person sitting in the chair, at least typically. So that doesn't necessarily seem to be a good explanation for most of these cases. That's led some to ball lightning, which behaves much more unpredictably and is not well understood. I think it's possible that ball lightning, or even regular lightning, could be an explanation for some of these cases, but i don't