Any party may appear in person or by counsel or other representative. A partner may appear on behalf of a partnership and an officer may appear on behalf of a corporation. Persons who appear as counsel or other representative must conform to the standards of conduct and ethics required of practitioners before the courts of the United States.

(a) Intervention. Any person desiring to become a party to a proceeding may move for leave to intervene. A motion for leave to intervene that is filed after the exchange of information pursuant to § 22.19(a) shall not be granted unless the movant shows good cause for its failure to file before such exchange of information. All requirements of these Consolidated Rules of Practice shall apply to a motion for leave to intervene as if the movant were a party. The Presiding Officer shall grant leave to intervene in all or part of the proceeding if: the movant claims an interest relating to the cause of action; a final order may as a practical matter impair the movant's ability to protect that interest; and the movant's interest is not adequately represented by existing parties. The intervenor shall be bound by any agreements, arrangements and other matters previously made in the proceeding unless otherwise ordered by the Presiding Officer or the Environmental Appeals Board for good cause.

(b) Non-party briefs. Any person who is not a party to a proceeding may move for leave to file a non-party brief. The motion shall identify the interest of the applicant and shall explain the relevance of the brief to the proceeding. All requirements of these Consolidated Rules of Practice shall apply to the motion as if the movant were a party. If the motion is granted, the Presiding Officer or Environmental Appeals Board shall issue an order setting the time for filing such brief. Any party to the proceeding may file a response to a non-party brief within 15 days after service of the non-party brief.

(a) Consolidation. The Presiding Officer or the Environmental Appeals Board may consolidate any or all matters at issue in two or more proceedings subject to these Consolidated Rules of Practice where: there exist common parties or common questions of fact or law; consolidation would expedite and simplify consideration of the issues; and consolidation would not adversely affect the rights of parties engaged in otherwise separate proceedings. Proceedings subject to subpart I of this part may be consolidated only upon the approval of all parties. Where a proceeding subject to the provisions of subpart I of this part is consolidated with a proceeding to which subpart I of this part does not apply, the procedures of subpart I of this part shall not apply to the consolidated proceeding.

(b) Severance. The Presiding Officer or the Environmental Appeals Board may, for good cause, order any proceedings severed with respect to any or all parties or issues.