(a) Written material identified as direct testimony or as an evidentiary exhibit and offered by a party in a hearing, and oral testimony, whether on direct or on cross-examination, is admissible as evidence unless the presiding officer excludes it (on objection of a party or on the presiding officer's own initiative) because it is irrelevant, immaterial, or unduly repetitive, or because its exclusion is necessary to enforce a specific requirement of this part relating to the admissibility of evidence.

(b) If a party objects to the admission or rejection of any evidence or to the limitation of the scope of any examination or cross-examination, the party shall state briefly the grounds for such objection. The transcript shall include any argument or debate thereon, unless the presiding officer, with the consent of all the parties, orders that such argument not be transcribed. The ruling and the reasons given therefor by the presiding officer on any objection shall be a part of the transcript. An automatic exception to that ruling will follow.

(c) Whenever evidence is deemed inadmissible, the party offering such evidence may make an offer of proof, which shall be included in the transcript. The offer of proof for excluded oral testimony shall consist of a brief statement describing the nature of the evidence excluded. If the evidence consists of a document or exhibit, it shall be inserted in the record in total. If the Administrator in reviewing the record under § 179.112 decides that the presiding officer's ruling in excluding the evidence was erroneous and prejudicial, the hearing may be reopened to permit the taking of such evidence, or, where appropriate, the Administrator may evaluate the evidence and proceed to a final decision.

(d) Official notice may be taken of Agency proceedings, any matter that might be judicially noticed by the courts of the United States, or any other fact within the knowledge and experience of the Agency as an expert agency. Any party shall be given adequate opportunity to show that such facts are erroneously noticed by presenting evidence to the contrary.