486—4.21 (10A,88) Intervention—appearance by nonparties.
	 4.21(1) A petition for leave to intervene may be filed at any stage of a proceeding before commencement of the hearing.
	 4.21(2) The petition shall set forth the interest of the petitioner in the proceeding and show that the participation of the petitioner will assist in the determination of the issues in question, and that the intervention will not unnecessarily delay the proceeding.
	 4.21(3) The employment appeal board or the administrative law judge may grant a petition for intervention to such an extent and upon such terms as the employment appeal board or the administrative law judge shall determine.