Mo. Rev. Stat. § 442.055
In the event that any premises to be rented, leased, sold, transferred, or conveyed is or was previously contaminated with radioactive material or other hazardous material, the owner, seller, landlord, or other transferor shall disclose in writing to the prospective lessee, purchaser, or transferee the fact the premises is or was previously contaminated with radioactive material or other hazardous material; provided that, the owner, seller, landlord, or other transferor has knowledge of such radioactive or other hazardous contamination. In the event that an owner, seller, landlord, or other transferor does not make the disclosure as required under this section*, and the person had knowledge of such radioactive or other hazardous contamination, the person shall be guilty of a class A misdemeanor. As used in this section, the term "knowledge" shall require the receipt by the owner, seller, landlord, or other transferor of a report stating affirmatively that the premises is or was previously contaminated with radioactive material or other hazardous material.
§ 442.055, RSMo