Every person called as a witness and who is giving oral testimony in a hearing shall swear or affirm that the testimony he or she is about to give in the hearing shall be the truth according to the provisions of RCW 5.28.020 through 5.28.060. If the witness is testifying from outside the jurisdiction, the hearings examiner may require the witness to agree to be bound by the laws of the state of Washington for purposes of the oath or affirmation.
Wash. Admin. Code § 308-101-200