"slow and long process" that would include a lot of forensic testing and could last "months if not years."

I mean. This line strikes me as a bit odd. It seems like natural gas explosions are common enough to be self-evident, which means it shouldn't take years to do an investigation. Also, the size of the fireball, that really seems like a natural gas explosion. And if its not a natural gas explosion, what then? For example, this explosion in Pendleton was the result of home made fireworks.