Mo. Rev. Stat. § 260.295: Refrigerants, use of — building codes not to prohibit if approved for use under federal law.

No building code adopted by a political subdivision shall prohibit the use of refrigerants that are approved for use under the provisions of 42 U.S.C. Section 7671k or the regulations promulgated thereunder, provided any related equipment is installed in accordance with the provisions of 42 U.S.C. Section 7671k or the regulations promulgated thereunder. Any provision of a building code that violates this section shall be null and void.