(a) The department shall arrange for the presentation of evidence concerning the allegations in the notice of hearing and in the pleadings, and the party or parties discharging any matter causing or contributing to the pollution.

(b) Each witness shall, before testifying, be sworn or make affirmation.

(c) When necessary, in order to prevent undue prolongation of the hearing, the hearing officer may limit the number of times any witness may testify, the repetitious examination or cross-examination of witnesses, or the amount of corroborative or cumulative testimony.

(d) The rules of evidence shall not be strictly applied; provided, however, the hearing officer shall exclude irrelevant, immaterial or unduly repetitious evidence.

(e) Every party shall have the right to present evidence and cross-examine witnesses.

(f) The hearing officer may take official notice of statutes of the United States or of the State of New York and of duly promulgated regulations of United States agencies or agencies of the State of New York.

(g) The hearing officer may take official notice of a material fact not appearing in the evidence in the record, but any party excepting thereto prior to the conclusion of the hearing if such fact be taken notice of during the hearing, or a party who shall make written application therefor at any time prior to 10 days after service of notice of findings apprising him of such noticed fact, shall be afforded an opportunity to show the contrary.

(h) Unless the hearing officer orders otherwise, questions calling for the opinion of an expert witness need not be hypothetical in form, and the witness may state his opinion and reasons without first specifying the data upon which it is based. Upon cross-examination, he may be required to specify the data and other criteria supporting the opinion.

(i) Any writing or record, whether in the form of an entry in a book or otherwise, made as a memorandum or record of any act, transaction, occurrence or event, shall be admissible in evidence in proof of that act, transaction, occurrence or event, if the hearing officer finds that it was made in the regular course of any business and that it was the regular course of such business to make it, at the time of the act, transaction, occurrence or event, or within a reasonable time thereafter. All other circumstances of the making of the memorandum or record, including lack of personal knowledge by the maker, may be proved to affect its weight, but they shall not affect its admissibility. The term business includes a business, profession, occupation and calling of every kind.

(j) Where a public officer is required or authorized by special provision of law, to make a certificate or an affidavit to a fact ascertained, or an act performed by him in the course of his official duty, and to file or deposit it in a public office of the State, the certificate or affidavit so filed or deposited is prima facie evidence of the facts stated.

(k) A statement signed by an officer or a deputy of an officer having legal custody of specified official records of the United States or of any State, territory or jurisdiction of the United States, or of any court thereof, or kept in any public office thereof, that he has made diligent search of the records and has found no record or entry of a specified nature, is prima facie evidence that the records contain no such record or entry, provided that the statement is accompanied by a certificate that legal custody of the specified official records belongs to such person, which certificate shall be made by a person described in rule 4540 of the Civil Practice Law and Rules of the State of New York.

(l) All maps, surveys and official records affecting real property, which have been on file in the State in the office of the register of any county, any county clerk, any court of record or any department of the City of New York for more than 10 years, are prima facie evidence of their contents.

(m) Samples may be displayed at the hearing and may be described for purposes of the record, but need not be admitted in evidence as exhibits.

(n) Oral argument may be permitted by the hearing officer within his discretion and shall be reported as part of the record unless otherwise ordered.

(o) All written statements, charts, tabulations and similar data offered in evidence at the hearing shall, upon a showing satisfactory to the hearing officer of their authenticity, relevancy and materiality, be received in evidence and shall constitute a part of the record.

(p) Where the testimony of a witness refers to a statute, or a report or document, the hearing officer shall, after satisfying himself of the identity of such statute, report or document, determine whether the same shall be produced at the hearing and physically be made a part of the record or shall be incorporated in the record by reference.

(q) No evidence shall be received unless it be relevant to and probative of an issue defined by the pleadings or be probative of an allegation contained in the notice of hearing.

(r) A hearing shall be conducted as nearly as practicable in the manner of a trial by court.