Mo. Rev. Stat. § 287.370
Any employer or group of employers may enter into or continue any agreement with his or their employees to provide a system of compensation benefits or insurance in lieu of the compensation and insurance provided by this chapter. Such substitute system and insurance shall be subject to the approval of the director of the department of commerce and insurance and shall not be approved by him unless they confer benefits upon injured employees or their dependents at least equivalent to the benefits provided by this chapter, nor if they require contributions from employees, unless they confer benefits in addition to those provided under this chapter at least commensurate with such contribution. Appeals shall lie to the commission from any decision, award or order made by or under such substitute system. Such substitute system and insurance may be terminated by the director of the department of commerce and insurance on reasonable notice and hearing to the interested parties, if it shall appear that the same is not fairly administered, or if its operation shall disclose latent defects threatening its solvency or if for any other substantial reason it fails to accomplish the purposes of this chapter; and in this case the director of the department of commerce and insurance shall determine upon the proper distribution of all remaining assets, if any, subject to the right of any party in interest to have such action reviewed by a court of competent jurisdiction.
§ 287.370, RSMo