Wash. Rev. Code § 51.52.104
After all evidence has been presented at hearings conducted by an industrial appeals judge, who shall be an active or judicial member of the Washington state bar association, the industrial appeals judge shall enter a proposed or recommended decision and order which shall be in writing and shall contain findings and conclusions as to each contested issue of fact and law, as well as the order based thereon. The industrial appeals judge shall file the signed original of the proposed decision and order with the board, and copies thereof shall be mailed by the board to each party to the appeal and to each party's attorney or representative of record. Within twenty days, or such further time as the board may allow on written application of a party, filed within said twenty days from the date of communication of the proposed decision and order to the parties or their attorneys or representatives of record, any party may file with the board a written petition for review of the same. Filing of a petition for review is perfected by mailing or personally delivering the petition to the board's offices in Olympia. Such petition for review shall set forth in detail the grounds therefor and the party or parties filing the same shall be deemed to have waived all objections or irregularities not specifically set forth therein.
In the event no petition for review is filed as provided herein by any party, the proposed decision and order of the industrial appeals judge shall be adopted by the board and become the decision and order of the board, and no appeal may be taken therefrom to the courts. If an order adopting the proposed decision and order is not formally signed by the board on the day following the date the petition for review of the proposed decision and order is due, said proposed decision and order shall be deemed adopted by the board and become the decision and order of the board, and no appeal may be taken therefrom to the courts.
RCW 51.52.104
Effective dates-Severability-1971 ex.s. c 289: See RCW 51.98.060 and 51.98.070.