Mississippi Administrative Code
Title 11 - Mississippi Department of Environmental Quality
Part 5 - Underground Storage Tank Regulations
Chapter 2 - Mississippi Commission on Environmental Quality Underground Storage Tanks Regulations Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (Adopted March 22, 1989; Amended August 25, 2011, Last Amended August 23, 2018)
Appendix 11-5-2-280.4 - GUIDELINES FOR THE PERMANENT CLOSURE OF PETROLEUM UNDERGROUND STORAGE TANK SYSTEMS
Section 11-5-2-280.4-4 - SAMPLING LOCATIONS FOR TANKS
Section 11-5-2-280.4-4.4 - Tank Closure in Place or Change in Service
Since potentially contaminated soils cannot be seen during closure in place activities as when removing tank systems, the sampling requirements for closure in place are more conservative. You must follow the exact guidelines given in this document unless special circumstances do not allow such. Any alternative sampling plan must be submitted to the UST Branch for approval at the same time the "Notice of Intent to Permanently Close UST System(s)" form is submitted.
If "true" groundwater (refer to Section 3.2) is encountered during soil boring activities, groundwater samples must be collected from each boring that contains groundwater and each sample must be analyzed separately. Soil sampling must be conducted from those borings that do not have groundwater. In addition, regardless of whatever soil and/or groundwater sampling that is conducted, one soil sample must be collected from the boring that exhibited the highest level of petroleum contamination during the field screening process (see Section 4.4.4).
Tanks closed in place must be cleaned and filled with an inert solid material such as sand, concrete, virgin drilling mud or a "foam" material approved for such purposes. If virgin drilling mud is used, the mixture must consist of 25-30 pounds of bentonite per 42 gallon barrel of water and the pH must be between 6.5 and 8. All tank sludges removed during the cleaning process must be properly disposed of in accordance with all regulatory requirements.
