Section 159-10-003 - ASSESSING THE SITE AT CLOSURE OR CHANGE-IN-SERVICEThe requirement of 40 CFR 280.72 as it existed on July 15, 2015 are adopted and incorporated by reference.; and
003.01 If free product is present on the ground water at the time a tank is removed, sampling of the soil and ground water does not need to be conducted for the assessment report, provided the Department of Environment and Energy is notified and the owner and/or operator begins remedial action in accordance with Neb.Rev.Stat. §81-15, 123.003.02Analysis of samples. Soil and ground water samples taken at time of closure will be analyzed by laboratory methods to detect and quantify the presence of the regulated substances that have been stored in the tank system. 003.02A. Samples will be collected, transported and analyzed using sample collection procedures, instrumentation, and test methodologies approved by the Department of Environment and Energy. At a minimum the following additional requirements must be met: 003.02A1. Test methodology procedures regarding proper handling and preservation of samples will be followed.003.02A2. Proper chain of custody will be maintained for each sample.003.02A3. Samples will be immediately sealed in their appropriate containers after collection.003.03In-Place Closure Assessment003.03A. Soil borings must provide the necessary data to document site conditions. The soil borings will be a minimum of two inches in diameter and be completed using a hollow stem auger. Drilling to and sampling of ground water will be performed in accordance with the Department of Health and Human Services' Title 178. Evidence of petroleum contamination in the soils or ground water and the corresponding depth of contamination will be documented in the State Fire Marshal closure assessment report. Notification of any contamination will be made in accordance with 004.02 of this Chapter.003.03B.Tank Assessment003.03B1. One boring will be drilled through the backfill at each end of each tank. If the distance between any of the borings exceeds 25 feet, as measured along the excavation perimeter, a boring midway between the two is necessary.003.03B2. All borings will continue until evidence of soil contamination is no longer present, at which point a soil sample is collected for laboratory analysis. If evidence of soil contamination continues to ground water, then a sample of ground water for laboratory analysis is also required.003.03B3. One soil sample will be collected for every 10 feet of boring advancement. If ground water is encountered, one sample of ground water will be collected at the base of each boring. Each ground water and/or soil sample will be analyzed in accordance with 003.02 of this Chapter.003.03B4. Soil samples will be collected in a manner to minimize disturbance of the soil structure. The predominant soil type of each sample (e.g., clay, sand, gravel) will be recorded separately and submitted on a boring log as an addendum to the closure assessment report.003.03C.Line Assessment003.03C1. One boring will be drilled at the point where the product lines leave the tank excavation.003.03C2. One boring will be drilled within 3 feet of each dispenser island. The borings will be placed in the best estimated down gradient direction of ground water flow.003.03C3. If the running length of the product line between the borings required in 003.03C(C1) and 003.03C(C2) of this Chapter exceeds 25 feet, additional borings will be placed so borings are equally spaced and there is never more than 25 feet between any borings.003.03C4. All product line borings will conform to 003.03B2 of this Chapter.003.03C5. Samples will be collected and analyzed as required in 003.03B3 and 003.03B4 of this Chapter.003.04Removal Closure Assessment. All underground storage tanks and all product piping will be inspected for corrosion holes and/or other points of leakage. A description of the inspection methods, and if leakage is verified, a description of the cause and location must be submitted to the State Fire Marshal in the closure assessment report. Notification of any contamination will be made in accordance with 004.02 of this Chapter. 003.04A. Each tank, its associated piping, and dispenser will be visually inspected for holes, cracks, corrosion or any signs of leakage. All welds and seams must be thoroughly scraped and inspected. The capacity and dimensions of each tank will be recorded. Results of these inspections will be documented in the State Fire Marshal closure assessment report.003.04B. All piping must be exposed and inspected in place.003.05Tank Excavation003.05A. Backfill material will be removed to expose undisturbed native soils at the base of the excavation.003.05B. The base of the excavation will be inspected for contamination and, if present, the owner/operator has the option to over excavate all areas of contamination until clean soils are encountered. Over excavation done in this manner is subject to Neb.Rev.Stat §81-15, 123. To verify that soils are free of contamination, soil samples will be collected from the floor of the over excavated basin and analyzed in accordance with 003.02 of this Chapter.003.05C. The final disposal location of contaminated soil and each tank will be reported on the State Fire Marshal closure assessment report. Soil disposal procedures are subject to Department of Environment and Energy oversight.003.05D. One sample will be collected at each end of the tank from native soil at the base of the excavation for laboratory analysis. If signs of leakage/contamination are observed, additional native soil samples will be collected at the points of leakage for analysis. If groundwater is encountered and covers the entire excavation basin, one groundwater sample will be collected and analyzed. If groundwater does not cover the entire excavation basin, samples will be collected from the exposed soil as previously stated in this section and analyzed in addition to the groundwater sample. The groundwater and/or soil samples are to be prepared and analyzed in accordance with 003.02 of this Chapter.003.06 Line Excavation Assessment 003.06A. All product piping will be removed by trenching and exposing the entire length of the lines.003.06B. The procedures described in 003.04A and 003.04B of this Chapter will be followed.003.06C. One soil sample will be collected for laboratory analysis every ten (10) feet from the native soil at the base of the piping excavation, beginning at the tank excavation perimeter and extending to the dispensers. If signs of leakage/contamination are observed, additional soil samples will be collected for analysis at the points of leakage. The soil samples are to be prepared and analyzed in accordance with 003.02 of this Chapter.003.06D. The base of the excavation will be inspected for contamination and, if present, the owner/operator may over excavate according to the procedures in 003.05B and 003.05C of this Chapter.159 Neb. Admin. Code, ch. 10, § 003