As an aside, here's an interesting piece from Nathaniel Barnaby, a Head of British naval construction in the late c19th. He's describing conditions below the waterline in a steam-powered 'ironclad' warship:
Imagine in the engine rooms a temperature of 110 degrees despite two upcast shafts with fans sucking air out ... Imagine 120 stokers breathing thick black coal dust in the far bunkers shovelling coals into barrows, wheeling them to the stokeholes at either end of the engine rooms. Imagine the oven heat about the boilers, each fourteen feet high, the livid glare from the open furnace doors as Welsh nuggets are scattered in by grey-skinned men, their faces and arms chased with rivulets of black sweat.
There doesn't seem to have been any concern back then that breathing in thick black coal dust might be injurious to the health. And on top of that British matelots had to cope with the effects of smoking Capstan Full Strength!