How is hexavalent chromium formed during welding?

Hexavalent chromium (Cr(VI)) forms when high temperatures oxidize chromium-containing metals during welding and other thermal processes. Stainless steel naturally contains chromium in its less harmful trivalent form (Cr(III)), but welding heat can transform it into toxic hex chrome fumes that may be inhaled by workers.

Several factors can increase hexavalent chromium exposure during welding, including:

• Welding method used: some processes create more fumes than others
• Chromium content of the metal: higher chromium content may increase exposure risk
• Contaminants or additional metals in the base material
• Welding temperature and duration