(a) The Presiding Officer may certify a ruling for interlocutory review by the Administrator where a party so requests and the Presiding Officer concludes that (1) the ruling from which review is sought involves an important question as to which there is substantial ground for difference of opinion, and (2) either (i) a subsequent reversal of his ruling would be likely to result in substantial delay or expense if left to the conclusion of the proceedings, or (ii) a ruling on the question by the Administrator would be of material assistance in expediting the hearing. The certificate shall be in writing and shall specify the material relevant to the ruling certified. If the Administrator determines that interlocutory review is not warranted, he may decline to consider the ruling which has been certified.

(b) Where the Presiding Officer declines to certify a ruling the party who had requested certification may apply to the Administrator for interlocutory review, or the Administrator may on his own motion direct that any matter be submitted to him for review, subject to the standards for review set forth in paragraph (a) of this section. An application for review shall be in writing and shall briefly state the grounds relied on. If the Administrator takes no action with respect to such application for interlocutory review within 15 days of its filing, such application shall be deemed to have been denied.

(c) Unless otherwise ordered by the Presiding Officer or the Administrator, the hearing shall continue pending consideration by the Administrator of any ruling or request for interlocutory review.

(d) Unless otherwise ordered by the Presiding Officer or the Administrator, briefs in response to any application for interlocutory review may be filed by any party within five days of the filing of the application for review.

(e) Failure to request or obtain interlocutory review does not waive the rights of any party to complain of a ruling following completion of the hearing. Within five days following the close of a hearing under this part, any party may apply to the Administrator for post-hearing review of any procedural ruling, or any ruling made by the Presiding Officer concerning the admission or exclusion of evidence to which timely objection was made. Within seven days following the filing of any such application any other party may file a brief in response thereto.

(f) If the Administrator on review under paragraph (e) of this section determines that evidence was improperly excluded, he may order its admission without remand for further proceedings, or may remand with such instructions as he deems appropriate concerning cross-examination, or opportunity for any party to submit further evidence, with respect to such evidence as he directs should be admitted. In making his determination whether to remand, the Administrator shall consider whether the statutory time restraints permit a remand, and whether it would be constructive to allow cross-examination or further evidence with respect to the newly admitted evidence. If evidence is admitted without cross-examination, the Administrator shall consider the lack of opportunity for cross-examination in determining the weight to be given such evidence.

(g) Motions shall be brief, in writing, and may be filed at any time following the publication of the proposed effluent standards, unless otherwise ordered by the Presiding Officer or the Administrator. Unless otherwise ordered or provided in these rules, responses to motions may be filed within seven days of the actual filing of the motion with the hearing clerk.