I don't know why they catch on fire sometimes, I think maybe because of the tailpipe exhaust.
Maybe someone threw a cigarette or maybe it's because of the extreme heat of the exhaust, it's very dangerous for people, they should be careful,right?
It could be that they put to much on it and it caught fire because it was hot out. The thermal density can get trapped and it becomes very hot on the inside, like a bunch of blankets.
