My good friend in the industry says this is common.
They are supposed to patrol and check the operations but most will sleep from 3am till the next shift comes in. That's why the fires are in the early mornings.
Fire with or without explosion matters alot.
Uncle guess in this case the chemicals are non explosive kind so likely no casualties even the fire may appear to be seen big.
Uncle recall the shipyard explosion in the 70s whereby 1 of uncle's childhood neighbour father was in 1 of of the dead list