20 CFR § 258.3 - Application for witnesses.
(a) Any person or persons conducting a hearing pursuant to the provisions of this part or part 260 of this chapter may, upon such person's or persons' own motion or upon application of any party to such hearing, issue a subpoena for a witness or witnesses. An application for a subpoena shall be by affidavit filed with the person or persons conducting the hearing within such period of time as will permit service and return of a subpoena prior to the date set for the hearing at which the witness is to appear, but in no case shall such application be filed later than 10 days prior to the date of hearing. The application shall set forth:
(1) The name and address of the witness;
(2) The title of the matter to be heard, i.e., names of parties;
(3) The issue to which the testimony of the witness will be directed;
(4) The substance of the testimony which such witness is expected to give or the facts to which such witness will testify; and
(5) The specific books, papers or documents which are requested, if a subpoena duces tecum is applied for.
(b) In addition to the above, the party filing such application shall, at the time of filing, deposit therewith a sum of money sufficient to cover the fees and transportation allowance of the witness, or, in lieu thereof, shall state in the application that satisfactory arrangements have been made with the witness for the direct payment of his or her fees and transportation allowance and any other allowable expense.