[LWJ]

Not just grinding dust. Welding turns the filler metal into a plasma arc. Meaning, it becomes gaseous. Most of this is deposited on the project area. Some of the gaseous metals floats away. Into lungs, onto paint, and into engines.

The above is NOT an absolute but rather my translation of what I believe is going on. I am not a stem guy, but I did sell fume extraction to welders long ago. I also did workers' comp to heavy industry. The airborne crap is a real deal.