(1) Employers that are organized pursuant to chapter 36.100, 36.102, or 81.112 RCW, who have become retirement system employers since 1993, and who have previously excluded some of their employees from retirement system membership pursuant to the limitation in RCW 41.40.023(4), shall have the option until December 31, 1999, to terminate their status as a retirement system employer with regard to persons employed after the date of their election.

(2) If a government unit terminates its status as an employer pursuant to this section its employees as of the date of the election who are members shall be eligible to continue their membership in the retirement system, if otherwise eligible under this chapter, for the duration of their continuous employment with that employer.

(3) If a government unit subject to this section does not elect to terminate its status as a retirement system employer it may either: (a) Continue to exclude from membership those employees who were excluded pursuant to the limitation in RCW 41.40.023(4) prior to July 25, 1999; or [(b)] include such employees in the retirement system, if otherwise eligible under this chapter, for service rendered on or after July 25, 1999, and after the employer's election.