What's in welding fume particles?

Welding fumes are basically a cloud of very tiny metal particles mixed with gases created when the metal gets heated above its melting point. What’s inside depends on the type of welding and the material being worked on, but the common ingredients include iron oxide, manganese, nickel, chromium, aluminium and copper. If stainless steel is involved, you often see chromium (including hexavalent chromium), which is more harmful.

There’s also a gas component — things like ozone, nitrogen oxides and carbon monoxide can appear depending on the welding method. The trouble is these particles are so small that they can reach deep into the lungs, and the gases can irritate airways or cause longer-term health issues if exposure isn’t controlled well.