(1) A supervisory committee of at least three members must be elected at the annual membership meeting of the credit union. Members of the supervisory committee shall serve a term of three years, unless sooner removed under this chapter or until their successors are qualified and elected or appointed. The members of the supervisory committee shall be divided into classes so that as equal a number as is possible is elected each year.

(2) At least one supervisory committee member may attend each regular meeting of the board. However, supervisory committee members may be excluded from executive sessions of board meetings.

(3)(a) If a supervisory committee member is absent from more than one-third of the committee meetings in any twelve-month period in a term without being reasonably excused by the committee, the member shall no longer serve as a member of the committee for the period remaining in the term.

(b) The supervisory committee shall promptly notify the member that he or she shall no longer serve as a committee member. Failure to provide notice does not affect the termination of the member's service under (a) of this subsection.

(4) A supervisory committee member must be a natural person and a member of the credit union. If a member of the supervisory committee ceases to be a member of the credit union, the member shall no longer serve as a committee member. The chairperson of the supervisory committee may not serve as a board officer.

(5) Except as provided in subsection (6) of this section, any vacancy on the committee must be filled by an interim member appointed by the committee, unless the interim member would serve a term of fewer than ninety days. Interim members appointed to fill vacancies created by expansion of the committee will serve until the next annual meeting of members. Other interim members may serve out the unexpired term of the former member, unless provided otherwise by the credit union's bylaws. However, if all positions on the committee are vacant at the same time, the board may appoint interim members to serve until the next annual membership meeting.

(6) In the case of a merger between two credit unions pursuant to RCW 31.12.461, a supervisory committee member of the merging credit union may continue to serve as a supervisory committee member of the continuing credit union for a period not to exceed the equivalent of the duration of his or her unexpired term on the supervisory committee of the merging credit union, provided that the approved plan of merger or other agreement approved by the director provides for such service on the continuing credit union's supervisory committee with a corresponding expansion in the size of the continuing credit union's supervisory committee.

(7) No operating officer or employee of a credit union may serve on the credit union's supervisory committee. No more than one director may be a member of the supervisory committee at the same time, unless provided otherwise by the credit union's bylaws. No member of the supervisory committee may serve on the credit committee or investment committee of the credit union while serving on the supervisory committee.

(8) A credit union may establish an audit committee in lieu of a supervisory committee. An audit committee and its members possess the same duties and powers, and are subject to the same limitations as a supervisory committee and its members pursuant to this chapter.