I did a couple of years at the NASSCO shipyard in San Diego as a welder after the first .com crash.

The (literal) toxic work environment is why I left welding, even though I genuinely enjoyed the work. But I was already starting to see real changes in my health, even though I was super careful about respirator use, etc. What really sealed the deal was learning that my shift lead, who I thought was a good decade older than me, was actually a few years younger, but had just been welding longer, with the body damage to show for it.