The light emitted from a weld arc is brighter than that of the sun. Do not look at the arc without wearing a full-faced welding mask with a shade 10 or darker filter plate.

Always make sure the weld curtains are in place between the welder(s) and other people in the shop. Be sure to cover any exposed skin, including cuff and collar areas, while welding or observing inside the weld area. The rays from the arc can cause a UV burn much worse than a sunburn.

Observers may use a cardboard mask with a shade 10 filter plate.