Wash. Rev. Code § 41.56.125
Except for law enforcement personnel grievance arbitrations subject to RCW 41.58.070, in addition to any other method for selecting arbitrators, the parties may request the public employment relations commission to, and the commission shall, appoint a qualified person who may be an employee of the commission to act as an arbitrator to assist in the resolution of a labor dispute between such public employer and such bargaining representative arising from the application of the matters contained in a collective bargaining agreement. The arbitrator shall conduct such arbitration of such dispute in a manner as provided for in the collective bargaining agreement: PROVIDED, That the commission shall not collect any fees or charges from such public employer or such bargaining representative for services performed by the commission under the provisions of this chapter: PROVIDED FURTHER, That the provisions of chapter 49.08 RCW shall have no application to this chapter.
RCW 41.56.125