(1) Any party may file a written petition for administrative review of an initial order issued under WAC 246-10-503 or 246-10-608 stating the specific grounds upon which exception is taken and the relief requested.

(2) The secretary, upon his or her own motion, may petition for administrative review of an initial order.

(3) Petitions for administrative review must be served upon the opposing party and filed with the adjudicative clerk's office within twenty-one days of service of the initial order.

(4) The opposing party may file a response to a petition for administrative review filed as provided in this section. The response shall be filed at the adjudicative clerk's office. The party filing the response shall serve a copy of the response upon the party requesting administrative review. If the initial order was entered pursuant to WAC 246-10-503, the response shall be filed within ten days of service of the petition. In all other matters, the response shall be filed within twenty days of service of the petition.

(5) If a party or the secretary does not request timely administrative review of an initial order as described in this section, or a request for administrative review is dismissed, an initial order becomes a final order at 5:00 p.m. on the twenty-first calendar day after the adjudicative clerk's office serves the initial order.