You can see the water heaters in the room on the helicopter coverage. Probably a slow leak in one of the gas lines built up until it was ignited by the boiler next door.
5 critical injuries
3 in UCSD burn center (sounds like 3 of those 5)
and 8 others injured (varying degree)
Still saying 13 total at hospitals.
Fire dept guy says that they are amazed that there were not more injuries and AMAZED that the injuries were not far more serious given the strength and degree of the explosion.
The response was incredible and incredibly fast per all those on scene that are talking.
There will be a presser at 4:30 local time but again saying it’s definitely NOT terrorism and is related to what’s going on at the construction site.