(1) The department and the attorney general may intervene by right within fifteen days from the date of receipt of the petition for review by the department or the attorney general pursuant to RCW 90.58.180(1) in any matter set out therein.

(2) The presiding officer may grant a petition for intervention by any person at any time, upon determining that the petitioner qualifies as an intervenor pursuant to civil rule 24, that the intervention will serve the interests of justice and that the prompt and orderly conduct of the appeal will not be impaired.

(3) The presiding officer may impose conditions upon the intervenor's participation in the proceedings.