Wash. Rev. Code § 43.08.120
The state treasurer may appoint an assistant state treasurer, who shall have the power to perform any act or duty which may be performed by the state treasurer, and in case of a vacancy in the office of state treasurer, perform the duties of the office until the vacancy is filled as provided by law.
The state treasurer may appoint no more than three deputy state treasurers, who shall have the power to perform any act or duty which may be performed by the state treasurer.
The assistant state treasurer and the deputy state treasurers shall be exempt from the provisions of chapter 41.06 RCW and shall hold office at the pleasure of the state treasurer; they shall, before entering upon the duties of their office, take and subscribe, and file with the secretary of state, the oath of office provided by law for other state officers.
The state treasurer shall be responsible on his or her official bond for all official acts of the assistant state treasurer and the deputy state treasurers.
RCW 43.08.120