My hot take on why every time something chemical explodes people say "IT& #39;S GOTTA BE A NUKE" is that a) most people do really believe that mushroom-like clouds are unique to nukes (they aren& #39;t), b) most people (in the West) don& #39;t have any sense of scale for explosions.
I mean, just to give you a sense of the latter, here& #39;s the Trinity bomb& #39;s first 16 seconds, with the Empire State Building for scale.
And the mushroom clouds from these first nuclear weapons were HUGE, by human standards. Like, "hard to actually imagine" huge. As I like to tell everyone who looks at the NYC skyline with me, the Hiroshima cloud rose to 11X the height of the new WTC building over 15 minutes.