Welding-arc UV reaching the DNA inside a skin cell Cross-section of a welder's exposed skin. UV from the arc arrives directly and reflected off nearby surfaces. UVB rays stop in the epidermis and burn the skin; UVA rays reach deeper, into the dermis. A zoomed-in skin cell shows UV damaging its DNA, and that damage building up over a career. SURFACE · FOREARM PHASE 1 · HEALTHY CROSS-SECTION, NOT TO SCALE Damage UV kinks the DNA. Damage thatisn’t repaired stays and builds up. DNA The cell’s instructions, heldin its nucleus. Skin cell One cell from the base of theepidermis, zoomed in. Arc burn Red and painful, like a sunburn.Underneath, UV damages DNA. Arc UV Direct and reflected. UVB burns;UVA reaches deeper, into the dermis. LEGEND UVB UVA DNA damage

UV hazard: R&R Lotion, Protecting Welders from the Dangers of UV Radiation, white paper (2023), hazard sections; Skin Cancer: Causes, Prevention and Treatment, white paper (2024). Illustration for education only.