Status of party and of intervenor as party in interest

(a) Party as party in interest. By the decision of a contested case the board or division shall dispose of the legal rights, duties and privileges of each party designated or admitted to participate as a party in the proceeding. Each such party is deemed to be a party in interest who may be aggrieved by any final decision, order or ruling of the board or division. (b) Status of a nonparty that has been admitted to participate. Status as a nonparty or as an intervenor shall not be deemed to be an expression by the board or division that the person permitted to intervene is a party in interest who may be aggrieved by any final decision, order or ruling of the board or division unless the presiding officer explicitly so states.