From “Welder’s Anthrax: A Review of an Occupational Disease”: “Evidence suggests that the inhalation of ferrous and other metal fumes in the workplace may predisposeworkers to lung infections. The mechanisms associated with the immunosuppressive effects of metal fumes after inhalation are mostly unknown. Theories have included that metal fumes (or iron) act as a growth nutrient for bacteria, enhance the binding of bacteria to lung tissues, or impair immune responses in the lung through oxidative stress.”