5 C.F.R. § 842.208 – Firefighters, customs and border protection officers, law enforcement officers, members of the Capitol or Supreme Court Police, and nuclear materials couriers.

(a) An employee who separates from service, except by removal for cause on charges of delinquency or misconduct, is entitled to an annuity—
1. (1) After completing any combination of service as a firefighter, customs and border protection officer, law enforcement officer, member of the Capitol or Supreme Court Police, or nuclear materials courier totaling 25 years; or
2. (2) After becoming age 50 and completing any combination of service as a firefighter, customs and border protection officer, law enforcement officer, member of the Capitol or Supreme Court Police, or nuclear materials courier totaling 20 years.
(b) An annuity payable under paragraph (a) of this section commences on the first day of the month following separation.

[52 FR 4473, Feb. 11, 1987, as amended at 65 FR 2524, Jan. 18, 2000; 76 FR 42000, July 18, 2011]