5 U.S. Code § 579 - Arbitration proceedings
(a) The arbitrator shall set a time and place for the hearing on the dispute and shall notify the parties not less than 5 days before the hearing.
(b) Any party wishing a record of the hearing shall—
(1) The parties to the arbitration are entitled to be heard, to present evidence material to the controversy, and to cross-examine witnesses appearing at the hearing.
(2) The arbitrator may, with the consent of the parties, conduct all or part of the hearing by telephone, television, computer, or other electronic means, if each party has an opportunity to participate.
(4) The arbitrator may receive any oral or documentary evidence, except that irrelevant, immaterial, unduly repetitious, or privileged evidence may be excluded by the arbitrator.
(d) No interested person shall make or knowingly cause to be made to the arbitrator an unauthorized ex parte communication relevant to the merits of the proceeding, unless the parties agree otherwise. If a communication is made in violation of this subsection, the arbitrator shall ensure that a memorandum of the communication is prepared and made a part of the record, and that an opportunity for rebuttal is allowed. Upon receipt of a communication made in violation of this subsection, the arbitrator may, to the extent consistent with the interests of justice and the policies underlying this subchapter, require the offending party to show cause why the claim of such party should not be resolved against such party as a result of the improper conduct.