15 CFR 904.252 - Witnesses.
(a) Fees. Witnesses, other than employees of a Federal agency, summoned in an administrative proceeding, including discovery, shall receive the same fees and mileage as witnesses in the courts of the United States.
(c) Witness exclusion. Witnesses who are not parties may be excluded from the hearing room prior to the taking of their testimony. An authorized officer is considered a party for the purposes of this subsection.
(d) Oath or affirmation. Witnesses shall testify under oath or affirmation requiring the witness to declare that the witness will testify truthfully.
(e) Failure or refusal to testify. If a witness fails or refuses to testify, the failure or refusal to answer any question found by the Judge to be proper may be grounds for striking all or part of the testimony given by the witness, or any other action deemed appropriate by the Judge.
(f) Testimony in a foreign language. If a witness is expected to testify in a language other than the English language, the party sponsoring the witness must provide for the services of an interpreter and advise opposing counsel 10 days prior to the hearing concerning the extent to which interpreters are to be used. When available, the interpreter should be court certified under 28 U.S.C. 1827.