40 CFR 209.26 - Evidence.
(a) The official transcripts and exhibits, together with all papers and requests filed in the proceeding, shall constitute the record. Evidence may be received at the hearing even though inadmissible under the rules of evidence applicable to judicial proceedings, provided it is relevant, competent and material and not unduly repetitious. Immaterial or irrelevant parts of an admissible document shall be segregated and excluded so far as practicable. The weight to be given evidence shall be determined by its reliability and probative value.
(b) Witnesses shall be examined orally, under oath or affirmation, except as otherwise provided in these rules of practice or by the administrative law judge. Parties shall have the right to cross-examine a witness who appears at the hearing provided that such cross-examination is not unduly repetitious.
(c) Rulings of the administrative law judge on the admissibility of evidence, the propriety of examination and cross-examination and other procedural matters shall appear in the record.
(d) Parties shall automatically be presumed to have taken exception to an adverse ruling.