(1) A one hundred fifty thousand dollar death benefit shall be paid to the member's estate, or such person or persons, trust or organization as the member has nominated by written designation duly executed and filed with the department. If no such designated person or persons are still living at the time of the member's death, the member's death benefit shall be paid to the member's surviving spouse as if in fact the spouse had been nominated by written designation, or if there is no surviving spouse, then to the member's legal representatives.

(2) The benefit under this section shall be paid only where death occurs as a result of (a) injuries sustained in the course of employment; or (b) an occupational disease or infection that arises naturally and proximately out of employment covered under this chapter. The determination of eligibility for the benefit shall be made consistent with Title 51 RCW by the department of labor and industries. The department of labor and industries shall notify the department of retirement systems by order under RCW 51.52.050.