Section R. 205.3312 - InterventionRule 312.
(1) A person shall be permitted to intervene in a proceeding if either of the following occurs:(a) The applicant has an unconditional right to intervene conferred by law.(b) An interest of the applicant that may be directly affected is not adequately represented by the existing parties and the applicant may be bound by a decision in the proceeding.(2) A person may be permitted to intervene in a proceeding if any of the following occurs: (a) A statute of this state confers a conditional right to intervene.(b) The applicant's claim or defense and the proceeding have a question of law or fact in common.(c) The parties to the proceeding stipulate to the intervention.(3) When ruling on an application for intervention, the presiding officer shall consider whether the intervention will unduly delay or prejudice the adjudication of the rights of the original parties.Mich. Admin. Code R. 205.3312