Ground water can have hydrogen sulfide in it and its heavier thsn air. It would build up in the tank because it wont reach the vents. Very deadly and flammable. The tank was not purged with fresh air and tested for explosive gasses properly if at all. Thats basic confined space training. Among other things, Im a former confinded space rescue team member.
Great answer. Your training shows.
California. Surprised?
The tank would also have been a Permit Entry Confined Space.
Thanks! I was scratching my head wondering how a water tank explodes! Is H2S like swamp gas?
I don’t doubt your expertise. Still doesn’t explain why the FBI blew it up.