Lawnmower Man
My dad was a firefighter. He has a call where the husband has put the riding lawn mower in the walkout basement. Couple returned from their honeymoon and he went to move the lawnmower back outside, started it and the gas fumes caused the house to explode.
House was a total loss but luckily no one was severely injured. Storing anything with gas in a place with no ventilation; not smart. Story credit: Reddit / maybeCheri