Which item should you never carry in your pockets while welding?

Carrying matches or gas-filled lighters in your pockets while welding poses significant safety hazards. Welding generates extreme heat and can create sparks that may ignite combustible materials. Matches and lighters are sources of open flames and flammable substances, which could lead to catastrophic accidents, fires, or explosions in a welding environment.

Safety glasses, while essential for eye protection, are designed to be worn and not carried in pockets where they could get damaged or not be readily accessible. Pencils and notepads are generally harmless unless they somehow come into contact with molten materials or sparks, which is a less likely hazard. Wrenches and tools are necessary for a welder's job but should be securely stored rather than kept in pockets where they may fall out or cause injury. Thus, the prohibition of carrying matches or lighters is firmly based on promoting a safe working environment and preventing potential ignition sources.