Mo. Rev. Stat. § 319.107
The department shall establish standards of performance for maintaining a leak detection system, an inventory control system together with tank testing, or a comparable system or method designed to identify releases in a manner consistent with the protection of human health and the environment. The department shall establish requirements for maintaining records of any such monitoring, leak detection, inventory control, or tank testing system. An owner or operator of an underground storage tank, including an out-of-service or nonoperational tank, not found to be the source of a release for which the department has ordered nonroutine testing, who cooperates with the department, shall be reimbursed for all reasonable direct costs, as determined by the director, related to the testing and monitoring costs associated with the detection of the alleged release incurred by such owner or operator, out of the underground storage tank insurance fund.
§ 319.107, RSMo