Years ago, my aunt and uncle had natural gas installed in their house.
The guy installing it didn’t check for leaks properly (from what I remember he tried to blow down the pipe and couldn’t, so he assumed it was okay) - turned out there was an open pipe that was blocked with some small debris which was blown out when they turned the gas on.
When they tried to light the gas fire for the first time the house blew up. Severe injuries for everyone, very lucky nobody got killed.
