People are used to having 25MWh of heating oil tanks in rural locations, although those are supposed to be stored away from the house.

Assuming heating oil is diesel, it's not very flammable and not a huge fire hazard. Soil pollution from leaks and spills seems like a bigger concern there. But I guess some people have large tanks of LPG which might be a bigger danger?

Every now and again there's a black swan event: https://en.wikipedia.org/wiki/Buncefield_fire