Lighthouse keepers.
Not a lot of people know this, but early lighthouses used a half toroid shaped bath of liquid mercury to float the massive glass fresnel lens on.
Needless to say the heat of the lamp, (particularly when they started using arc lights) made the atmosphere up there in the lamp room quite quite toxic, giving lighthouse keepers a similar reputation to the one hatmakers and (cough) fruitbats get to enjoy.
FB.