(a) Except as provided by Subsections (b) and (c), the commission by rule shall prohibit the issuance of a permit for a new hazardous waste landfill or an areal expansion of such a landfill if the landfill is to be located in the 100-year floodplain existing before site development, unless the landfill is to be located in an area with a flood depth of less than three feet.
(b) The commission by rule may allow an areal expansion of a landfill in a 100-year floodplain if it can be demonstrated to the satisfaction of the commission that the facility design will prevent the physical transport of any hazardous waste by a 100-year flood event.

(c) The commission by rule shall prohibit the issuance of a permit for a new commercial hazardous waste land disposal unit if the unit is to be located in a 100-year floodplain, unless the applicant can demonstrate to the satisfaction of the commission that the facility design will prevent the physical transport of any hazardous waste by a 100-year flood event.
(d) The commission by rule shall require an applicant to provide sufficient information to assure that a proposed hazardous waste landfill, areal expansion of such landfill, or new commercial hazardous waste land disposal unit is not subject to inundation of a 100-year flood event. An applicant or any other party may not rely solely on floodplain maps prepared by the Federal Emergency Management Agency or a successor agency to determine whether a hazardous waste landfill, areal expansion of such landfill, or commercial hazardous waste land disposal unit is subject to such an inundation.