I remember working in a large production commercial bakery, the summer after Highschool. Large ovens to raise the dough, and even hotter large ovens to cook the product.
Outside it could be over 100° F, inside it would routinely be 115-120° F. There was constantly flour floating in the air. Being on the maintenance crew that cleaned and fixed the machines, I was required to wear a hair net, hard hat, earplugs, and safety glasses at all times.
So I would be sweating like a pig all day long, in a very hot and loud environment. The flour floating in the air would land on your skin, and form a paste when it mixed with your sweat. Trying to wash all the 'paste' off at the end of the shift, was always fun.
I recall thinking that if there is a Hell, this would have to be it.
The working conditions I've seen in several news stories about working in an Amazon warehouse, look pretty pleasant in comparison.