Sufficient anorebic decomposition, mixed with hot and dry climates like LA's and a buildup of flammable gases, can cause spontaneous combustion: https://en.wikipedia.org/wiki/Landfill_fire?wprov=sfla1

Here in PA we have dozens of coal seams and clum heaps and slag mountains on fire - and have for like decades. There's a special PA EPA fund for dealing with it.

The person you are responding to described fire. Think about it.