[pjd7]

They work with sulphuric acid, oxy/acetylene/propane torches. Some processes give off cyanide fumes. Ultrasonic baths with ammonia based solutions to clean polishing compounds off etc.

You need outside air ventilation.

There is lots of mechanical suction for things like polishing to capture the waste material for post processing.

Most will wear a leather apron for heat / burn protection and capturing fine dust/dirt from polishing compounds. I suppose you could destroy that eventually in a giant smelter.