Mo. Rev. Stat. § 321.322
1. If any property located within the boundaries of a fire protection district shall be included within a city having a population of at least two thousand five hundred but not more than fifty thousand which is not wholly within the fire protection district and which maintains a city fire department, then upon the date of actual inclusion of the property within the city, as determined by the annexation process, the city shall within sixty days assume by contract with the fire protection district all responsibility for payment in a lump sum or in installments an amount mutually agreed upon by the fire protection district and the city for the city to cover all obligations of the fire protection district to the area included within the city, and thereupon the fire protection district shall convey to the city the title, free and clear of all liens or encumbrances of any kind or nature, any such tangible real and personal property of the fire protection district as may be agreed upon, which is located within the part of the fire protection district located within the corporate limits of the city with full power in the city to use and dispose of such tangible real and personal property as the city deems best in the public interest, and the fire protection district shall no longer levy and collect any tax upon the property included within the corporate limits of the city; except that, if the city and the fire protection district cannot mutually agree to such an arrangement, then the city shall assume responsibility for fire protection in the annexed area on or before January first of the third calendar year following the actual inclusion of the property within the city, as determined by the annexation process, and furthermore the fire protection district shall not levy and collect any tax upon that property included within the corporate limits of the city after the date of inclusion of that property:
(5) On or before January first of the sixth calendar year occurring after the date on which the property was included within the city, the city shall pay to the fire protection district a fee equal to one-fifth of the amount of revenue which would have been generated during the previous calendar year by the fire protection district tax on the property in the area annexed which was formerly a part of the fire protection district.
Nothing contained in this section shall prohibit the ability of a city to negotiate contracts with a fire protection district for mutually agreeable services. This section shall also apply to those fire protection districts and cities which have not reached agreement on overlapping boundaries previous to August 28, 1990. Such fire protection districts and cities shall be treated as though inclusion of the annexed area took place on December thirty-first immediately following August 28, 1990.
(L. 1985 H.B. 167, et al. § 2, A.L. 1986 H.B. 861, A.L. 1988 S.B. 725, A.L. 1990 H.B. 1395 & 1448, A.L. 1991 S.B. 34, A.L. 1999 S.B. 160 & 82)