Colo. Rev. Stat. § 31-30.5-602
In municipalities, fire protection districts, and county improvement districts having a population of less than one hundred thousand, any old hire member who has reached the age of fifty years and who has served for a period of twenty years of active service in any such department in this state is entitled to a monthly pension equal to one-half the amount of the member's monthly salary as of the date of the member's retirement plus, if the governing body of the municipality, the board of directors of the fire protection district, or the board of the county improvement district authorizes such additional benefits, one-half of any increase in salary and longevity or additional pay based on length of service granted during the period of the member's retirement to the rank occupied by the member in said department. Any old hire member of a paid fire department of a municipality, fire protection district, or county improvement district, who has served prior time in a volunteer fire department in any municipality, fire protection district, or county improvement district in this state, in the event the member becomes a paid member, may be credited service time at their discretion, at the rate of one year of paid service for each four complete years of volunteer time; except that they shall not receive both a pension under part 11 of article 30 of this title and a service credit under this section.
C.R.S. § 31-30.5-602
This section was formerly numbered as § 31-30-408.