Mo. Rev. Stat. § 86.583

86.583. Municipalities in first class counties and certain cities may provide pensions — approval by voters. — 1. Any municipality in any county of the first class, and any other municipality in this state which now contains or may hereafter contain not more than one hundred thousand inhabitants nor less than three thousand inhabitants as determined by the last preceding federal census is hereby authorized to provide for the pensioning of the salaried members of its organized police force or fire department and the widows and minor children of deceased members; provided, however, that nothing in this section shall be construed to affect any pension or retirement system for members of an organized police force or fire department, and their widows or minor children, which has been established previously under authority of an act of the general assembly and which is in operation at the time of the passage of this section, and the provisions of law applicable to any such pension or retirement system shall not be deemed to be repealed or superseded by the provisions of this section. This section shall not take effect in any such city until approved by the voters thereof as herein provided. On order of the city council, or on petition of five percent of the voters of said city, the question shall be submitted to the voters.

2. The question shall be submitted in substantially the following form:

Shall the (police or firemen's insert one) pension plan be approved?

3. If a majority of the voters casting votes thereon is in favor of the question, this section shall take effect in said city thirty days after the submission of the question.

(L. 1945 p. 1267 § 1, A.L. 1955 p. 276, A.L. 1978 H.B. 971)