Working around hazardous products and chemicals on offshore vessels?

I’m a greenhorn with a few questions about safety on offshore ships and merchant ships. Do you have to work around, in or near any hazardous products like carcinogens either in the engine rooms or on deck? Is smoking banned on board as well? In construction you always see the warning labels (this product is known to cause a nasty disease in the state of CA). By the way, hats off to CA looking out for us all. I don’t want some see some Tex-ass oil baron living it up like Hugh Hefner some day while I’m in a hospital beleaguered by all sorts of diseases caused by how his boats are manufactured or by the chemicals used on them. Also, say you made a boatload of money and you want to enjoy it for a year and not work at. How easy is it to find another job at the same position when you’re done vacationing after that year, provided you have a track record of being a stupendous employee?