(1) In all determinations, cases, and appeals adjudicated by the employment security department under Title 50B RCW, the department is an "interested party."

(2) Other interested parties in determinations, cases, and appeals include:

(a) The employee or former employee; and

(b) An employer or former employer of that employee that is required to provide information to the department related to the determination or appeal in question.

(3) The department may designate an employee or employer as an interested party in other determinations made by the department.