https://www.wionews.com/world/davenport-iowa-building-collapse-8-rescued-many-feared-trapped-under-rubble-watch-video-here-597918
Looks like authorities are blaming a nat gas leak.
Not sure how nat gas cooking off could do that...
Yeah, more likely it was commiseration between building code people and the owners to let one more year pass without structural review and upkeep.