DISTRICTS ‑- PORT ‑- EMPLOYEES ‑- CONTRACT FOR ADDITIONAL PENSION PROGRAM Under the provisions of RCW 53.08.170 a port district may contribute to an additional pension program established by contract between a trade association acting as collective bargaining agent for various employers including a port district and a labor union representing, among others, certain employees of the port district even though the eligible employees of said port district are members of the Washington State Employees' Retirement System.