Mo. Rev. Stat. § 87.380
Any fire department existing by authority of the laws of this state, or any municipal authority thereof, in any city in this state now having or which may hereafter acquire a population of more than one hundred thousand inhabitants, is hereby authorized and empowered to create funds for the purpose of pensioning firemen, and affording relief to members of such fire department when sick, or who may become disabled in the service, or retired, and provide for the relief of the families and other dependents of such firemen in case of death, under such rules and regulations as may be enacted by the board of trustees of such funds, subject to the provisions of sections 87.380 to 87.490, and not inconsistent with the constitution and laws of this state.
§ 87.380, RSMo
RSMo 1939 § 9520