(a) The Board shall be composed of five permanent members appointed by the Secretary from among individuals who are especially qualified to serve thereon. Each permanent member shall serve an indefinite term subject to the discretion of the Secretary.

(b) The member designated by the Secretary as Chairman of the Board shall serve as chief administrative officer of the Board and shall have the authority, as delegated by the Secretary, to exercise all administrative functions necessary to operate the Board.

(c) The four remaining members shall be the associate members of the Board.

(d) Upon application of the Chairman of the Board, the Secretary may designate up to four Department of Labor administrative law judges to serve as temporary Board members in addition to the five permanent Board members. Up to four such temporary members may serve at any one time. The term of any temporary Board member shall not exceed 1 year from date of appointment.