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 11-5-2-280.4-4.3 - Removal of Two or More Tanks Within a Common Excavation
Section 11-5-2-280.4-4.3.1 - Removal of Two or More Tanks - No Sidewall Contamination Apparent
If no contamination is apparent in the sidewalls, only floor sampling is required. When the excavation is 50 feet or less in all dimensions, four samples must be collected from the floor of the excavation at a depth of one foot into the native soil. The samples must be collected from the areas of the floor that appear to be the most contaminated. However, you should also take into consideration the entire area of the excavation so that no two of the samples are collected from the same general area. If no area of the floor appears to be obviously contaminated, or the floor appears to be uniformly contaminated, the samples must be collected from each corner of the excavation as shown in Figure 3.
However, if the excavation is greater than 50 feet in any dimension, additional samples must be collected along each dimension of the excavation that is greater than 50 feet in length. The additional sample must be collected from the center of that dimension of the excavation as shown in Figure 4. Soil sampling must also be conducted in such a manner that no more than 50 feet exists between any two sampling points as measured along each dimension (side) of the excavation.
