§  1.331   Who may sign and issue.

   Subpenas requiring the attendance and testimony of witnesses, and
   subpenas requiring the production of any books, papers, schedules of
   charges, contracts, agreements, and documents relating to any matter
   under investigation or hearing, may be signed and issued as follows:

   (a) Hearings before the Commission en banc, an individual commissioner,
   or a panel of commissioners: By any commissioner participating in the
   conduct of the hearing.

   (b) Hearings before an administrative law judge: By the administrative
   law judge or, in his absence, by the Chief Administrative Law Judge.