Odd coincidence
This week two major fires in this quarter of Spokane were caused by igniting vapors. It's a rare cause, and both were rare circumstances.
(1)
A car exploded while driving, seriously injuring a man and his infant daughter. At first a gang-style bomb was suspected, but the man turned out to be a fantastically stupid dickhead. He was trying to use some kind of marijuana vaping device which involved lots of butane. The device failed, filling the car with butane gas. Dickhead still needed a smoke, so he lit a regular cigarette. BANG!
(2)
A house burned quickly, defeating the efforts of firemen. Remodelers had been applying lacquer to the floors without ventilating. When the vapors reached a gas pilot light, THUMP! In this case we have (somewhat) understandable ignorance, not fantastic stupidity. Natural gas came to Spokane quite recently, so pilot lights are still unfamiliar, not part of common experience.
VENTILATE, dammit! Windows are there for a reason!