Do welders have to be trained and judged competent by their employer ?

OSHA gives this reply in a Letter of Interpretation:

“Under paragraph 1910.252(a)(2)(xiii)(C), cutters and welders and their supervisors must be suitably trained in the safe operation of their equipment and the safe use of the process (system). The personnel requirements under paragraph 1910.253(a)(4) are applicable to a workman (an employer puts) in charge of an oxygen–fuel gas welding or cutting system to which welders or welding operators connect and use (or use connected) equipment. The workman in charge of a system may perform as a welder and welding operator to the extent that welding or cutting does not interfere with the employee’s responsibilities for safe operation of the system in accordance with the rules and instructions required under paragraph 1910.253(a)(4).