((a)) ** Designation of participants** The Director may from time to time designate employees of the Agency who shall be entitled to participate in the system. Employees so designated who elect to participate in the system are referred to in this chapter as “participants”.

((b)) ** Qualifying service** Designation of employees under this section may be made only from among employees of the Agency who have completed at least 5 years of qualifying service. For purposes of this chapter, qualifying service is service performed by an Agency employee in carrying out duties that are determined by the Director—

((1)) to be in support of intelligence activities abroad hazardous to life or health; or

((2)) to be so specialized because of security requirements as to be clearly distinguishable from normal government employment.

((c)) ** Election of employee to be participant**

((1)) ** Permanence of election** An employee of the Agency who elects to accept designation as a participant in the system shall remain a participant of the system for the duration of that individual’s employment with the Agency.

((2)) ** Irrevocability of election** Such an election shall be irrevocable except as and to the extent provided in .section 2151(d) of this title

((3)) ** Election not subject to approval** An election under this section is not subject to review or approval by the Director.