The San Bruno explosion was caused by a jet crash (F-18) or a missile or bomb discharged by the same. Multiple eyewitnesses saw and reported it! The area was quarantined as a hazardous-waste and crime site, and the NTSB could not even say whether the pipe was “seam welded” or not for three months!
see details at:

What was this F-18 doing, flying with bombs and missiles two days before “9-11”, 2010, only miles and hours away from San Bruno when the explosion occurred? Why not investigate some of the eyewitnesses that saw or heard the jet? Why not find out where that F-18 landed and took off from that day? Why not investigate where that fighter jet and its pilot are today?

Here is proof from the television show “Mythbusters” that compressed gas does not explode without explosives, necessary to detonate it!(unless concentrated oxygen is combined with it, which was NOT the case in the San Bruno jet-onation!
Part 1
Part 2