29 CFR 2.2: Employees attached to Washington office.

No person who has been an employee of the Department and attached to the Washington office of any bureau, board, division, or other agency thereof, shall be permitted to practice, appear, or act as attorney, agent, or representative before the Department or any branch or agent thereof, in connection with any case or administrative proceeding pending before such bureau, board, division, or other agency during the time of his employment with the Department, unless he shall first obtain the written consent thereto of the Secretary of Labor or his duly authorized representative.