(a) Order of proceeding. Except as may be ordered otherwise by the administrative law judge, the petitioner shall proceed first at a hearing.

(b) Burden of proof. The petitioner shall have the burden of proving his case by a preponderance of the evidence.

(c) Evidence—(1) Admissibility. A party shall be entitled to present its case or defense by oral or documentary evidence, to submit rebuttal evidence, and to conduct such cross-examination as may be required for full and true disclosure of the facts. Any oral or documentary evidence may be received, but the administrative law judge shall exclude evidence which is irrelevant, immaterial, or unduly repetitious.

(2) Testimony of witnesses. The testimony of a witness shall be upon oath or affirmation administered by the administrative law judge.

(3) Objections. If a party objects to admission or rejection of any evidence, limitation of the scope of any examination or cross-examination, or failure to limit such scope, he shall state briefly the grounds for such objection. Rulings on such objections shall appear in the record.

(4) Exceptions. Formal exception to an adverse ruling is not required.

(d) Official notice. Official notice may be taken of any material fact not appearing in evidence in the record, which is among the traditional matters of judicial notice or concerning which the Department of Labor by reason of its functions is presumed to be expert: Provided, That the parties shall be given adequate notice at the hearing or by reference in the presiding administrative law judge's decision of the matters so noticed and shall be given adequate opportunity to show the contrary.

(e) Transcript. Copies of the transcript of the hearing may be obtained by the parties upon written application filed with the reporter and payment of fees at the rate provided in the agreement with the reporter.