Section 18 AAC 75.075 - Secondary containment requirements for aboveground oil storage tanks(a) Onshore aboveground oil storage tanks must be located within a secondary containment area that has the capacity to hold the volume of the largest tank within the containment area, plus enough additional capacity to allow for local precipitation. Minimum secondary containment system requirements include (1) berms, dikes, or retaining walls that are constructed to prevent the release of spilled oil from within the containment area; and(2) with the exception of the area under a tank, components constructed of, or lined with, materials that are (A) adequately resistant to damage by the products stored to maintain sufficient impermeability;(B) resistant to damage from prevailing weather conditions;(C) sufficiently impermeable; and(D) resistant to operational damage.(b) In locations where physically feasible, aboveground oil storage tank areas at an offshore exploration or production facility must incorporate a secondary containment method to prevent oil spills from entering the water.(c) A secondary containment system must be maintained free of debris, vegetation, excessive accumulated water, or other materials or conditions that might interfere with the effectiveness of the system. Facility personnel shall visually check for the presence of oil leaks or spills within secondary containment areas during routine operations, and, unless precluded by safety concerns or weather conditions, shall conduct documented weekly inspections of secondary containment areas, including checking for (1) debris and vegetation;(2) proper alignment and operation of drain valves;(3) visible signs of oil leaks or spills; and(4) defects or failures of the secondary containment system.(d) Drainage of water accumulations from secondary containment areas that discharge directly to the land or waters of the state must be controlled by locally operated, positive close failsafe valves or other positive means to prevent a discharge. Valves must be kept closed and locked when not in use. The owner or operator shall inspect accumulated water before discharging it from a secondary containment area to ensure that no oil will be discharged and shall keep for five years a written record of each drainage operation and whether a sheen was present or not. A discharge of water to land is subject to a cleanup plan approved under 18 AAC 75.360, a corrective action plan approval under 18 AAC 78.260, or a wastewater discharge permit issued under 18 AAC 72. If the discharge of water from a secondary containment area is to surface waters or wetlands, either a permit under 18 AAC 72, a permit under 18 AAC 83, or a certified NPDES permit under 18 AAC 15.120 may be required.(e) An installation placed in service on or after May 14, 1992 is subject to the following: (1) impermeable liners or double bottoms that are chemically resistant to damage by the product being stored in the tank must be installed under all tanks, except for tanks containing viscous products exceeding 400 SUS (Saybolt Universal System) at storage temperatures; and(2) drains and other penetrations through secondary containment areas must be minimized consistent with facility operational requirements.(f) At an installation placed in service before May 14, 1992, in the event of a known or suspected discharge, the department may require installation of monitoring wells to detect oil or other hazardous substances in the groundwater if the local geology and groundwater conditions allow installation of monitoring wells, and if monitoring wells will not substantially increase the risk of contaminating groundwater.(g) The owner or operator of rail tank car and tank truck loading areas and permanent unloading areas must ensure that those loading and unloading areas(1) have a secondary containment system designed to contain the maximum capacity of any single compartment of the tank car or tank truck, including containment curbing and a trenching system or drains with drainage to a collection tank or device designed to handle a discharge;(2) are paved, surfaced, or lined with sufficiently impermeable materials;(3) are maintained free of debris, vegetation, excess accumulated water, or other materials or conditions that might interfere with the effectiveness of the system; and(4) have warning lights, warning signs, or a physical barrier system to prevent premature vehicular movement.(5) are visually inspected before any transfer operation or at least monthly.(h) Shop-fabricated aboveground oil storage tanks of a vaulted, self-diked, or double-walled design meeting the requirements of 18 AAC 75.066(c), (d), or (e) are not required to be placed within bermed, lined, secondary containment areas if those tanks are equipped with catchments that positively hold any fuel overflow due to tank overfill or divert it into an integral secondary containment area.Eff. 5/14/92, Register 122; am 12/30/2006, Register 180; am 2/5/2023, Register 245, April 2023Authority:AS 46.03.020
AS 46.04.030
AS 46.04.070