It was a fertilizer plant, so it was ammonium nitrate. Think of Timothy McVeigh and the Oklahama truck bomb.
Propane is what exploded in the GTA in I think 2008?
Propane is fairly inert. It needs to be between 3 and 9% propane to air for it to burn. If it was possible to drop a lit match in to a propane tank, the match would just go out.
Propane tanks will explode, but they need to be heated up to the point that the pressure relief valve can't keep up or fails, the tank itself ruptures and then boom.
If you ever get a leaky propane tank and a fire results and you can't turn off the tank or stop the leak, do NOT put out the flame as it's burning off the excess fuel, that if otherwise left alone would end up collecting and waiting for ignition like the house bomb in the video you're talking about.
I worked for a couple years directly with propane. Used to walk through clouds of the stuff without worry.
Jeeze, why did I think it was propane?
However, I won't call propane inert though. It does need a source of oxygen, but I won't classify it as inert