This proves it

'Gas' leak causes fiery end to surgery
Flatulence is being blamed for bringing a hospital patient's operation to a fiery end.

The man suffered minor burns in a brief but "dramatic" operating theatre fire. He had gone into the Southern Cross Hospital in Invercargill to have haemorrhoids, or piles, removed and was singed in the "exceedingly rare" incident involving his own gas.

link

My mother always insisted that you can't light a fart. I'm pretty sure you can, methane being flammable and all. I'm just hoping the New Zealand Herald is a reputable journal of opinion so that I can officially prove it to her.