Mo. Rev. Stat. § 393.460: Strata and formations not subject to condemnation.

No stratum or formation lying less than five hundred feet below the surface, and no stratum or formation containing potable water conforming to the mineral content standards of the United States Public Health Service, and no stratum or formation containing natural gas or oil producible through primary production methods in commercially paying quantities or producing domestic supplies of natural gas or oil, and no stratum or formation containing coal or the ores of lead, zinc, iron, copper, barium, or any precious mineral, producible on a commercially paying basis, shall be subject to be condemned for utilization for the underground storage of gas therein.