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Chapter 6
Maintenance Facilities Management
6.5. Under and Above-Ground Storage Tanks

Above ground storage tanks are used at Maintenance facilities to store fuel, oil, antifreeze, deicing agents and asphalt emulsion. Underground tanks most often contained fuel. These materials can pose potential threats to water quality if spilled or mixed with stormwater runoff. Many DOTs have removed underground storage tanks for petroleum products, except at major facilities, and replaced these with above ground tanks or credit cards to purchase fuel private sources. Environmental stewardship practices for preventing and addressing storage tank leaks and spills include those reviewed below.

Tank Registration Practices

Fuel/petroleum tanks are generally registered with the state environmental agency when they can hold in the range of more than 1,100 gallons in a total combined capacity of any aboveground and/or underground tanks which store petroleum products, gasoline, diesel, kerosene, used oil or heating fuel. All fuel/petroleum tanks storing used oil are registered regardless of tank size or site capacity. One exception to this registration requirement -- small tanks that are not manifold and hold less than 1,100 gallons of heating oil for on-site use are exempt from this regulation. [N]

  • Petroleum Bulk Storage (PBS) Registration certificate should be posted near the tank location and renewed every five (5) years.
  • The PBS certificate should be updated whenever a tank removed or modified or added to reflect all current tanks.
  • The state environmental agency is notified prior to any tank removals.

Tank Equipment and Recordkeeping Practices

  • In both aboveground and underground petroleum storage tanks color-coded fill ports are used per the American Petroleum Institute's color and symbol code
  • In both aboveground and underground petroleum storage tanks the color and symbol code is identified on each fill port
  • Typical DOT petroleum storage tank port colors and codes are: Diesel - Yellow; Unleaded Gasoline - White with Black Cross; Kerosene - Brown
  • In both aboveground and underground petroleum storage tanks operating valves are present on all gravity-drained tanks
  • In both aboveground and underground petroleum storage tanks automatic shut-off valves such as solenoid valves on gravity-fed systems and shear valves on pumped dispensing systems are present to prevent any leaks in case of a pipe or hose failure
  • In both aboveground and underground petroleum storage tanks check valves are present for backflow prevention on tanks filled by pumping
  • For underground petroleum tanks monitor the inventory by measuring use, deliveries, losses or gains, and bottom water levels daily.
  • For underground petroleum tanks record inventories to the nearest tenth of a gallon if feasible,
  • For underground petroleum tanks reconcile records every ten days and retain all records for at least five years.
  • For underground petroleum tanks report inventory losses or gains of product that are more than:
    • 0.75 percent of the tank volume in a ten day period
    • 7.5 gallons for every 1,000 gallons delivered over a ten day period or 0.75 percent of the throughput or amount dispensed over a ten day period
    • Or if water seems to be accumulating during any ten (10) day period
  • When the cause of losses or gains in underground petroleum tanks cannot be explained within 48 hours, the Department of Environmental Conservation's Regional Spill Engineer is contacted and the tank is taken out of service
  • Tightness testing is required every five (5) years when underground tank systems are not protected and hold more than 1,100 gallons. (Protected systems are those that were installed with corrosion-resistant tank and piping and a leak monitoring system)
  • For underground petroleum tanks monitor corrosion-resistant tanks and pipes at the manufacturer's recommended schedule.
  • Steel USTs with corrosion protection should comply with the following requirements to ensure that releases due to corrosion are prevented for as long as the UST is used to store regulated substances.
  • For underground petroleum tanks inspect leak detection systems or double-walled tanks at least weekly, and other monitoring systems monthly
  • For underground petroleum tanks check any cathodic protection systems at least annually
  • Tanks (tanks for on-site heating are exempt) that hold 110 gallons or more are required upgrade to meet federal underground tank storage requirements. These federal standards included leak detection systems, corrosion protection, and spill/overfill prevention features.
  • For aboveground petroleum tanks inspect monthly the exterior surfaces of tanks, pipes, valves, leak detection systems and other equipment to identify any cracks, wear, corrosion, settling, separation or other problems. Keep records with the date and signature of the inspector for ten (10) years.
  • For aboveground petroleum tanks perform secondary containment and internal inspections every ten (10) years conducted by qualified firms for any tanks of greater than 10,000 gallon capacity that rest on the ground. Secondary containment may be required for smaller tanks that could reasonably be expected to discharge to waters of the state.
  • For aboveground petroleum tanks gauges accurately showing the product level are present unless a high level alarm or a cutoff controller is present. The design and working capacities and tank identification number must be clearly marked on the tank and at the gauge.
  • Erosion is the main concern with earthen emergency spill containment. Dried weeds and grass present a fire hazard. Animals can burrow through earth dikes. Concrete structures are susceptible to cracking and frost damage. A weekly inspection schedule should be developed to address these problems so they can be repaired promptly. Individual site-specific checklists should be developed to reflect site specific concerns. The following is a list of key items to be addressed in the periodic inspection of ASTs. Each AST should be inspected at least weekly.
    • Presence and/or volume of oil or water in the containment area
    • Soil color changes; noticeable sheen on water puddles
    • Visual observance of tanks, pumps, valves, and pipe connections
    • Unusually strong odor of stored material
    • Storage tank overflowing
    • Determination of accumulated liquids contained in area (i.e. uncontaminated stormwater, contaminated runoff, or pure product.)
  • New UST systems should be properly installed in accordance with industry codes of practices. At a minimum, new underground storage tank systems including piping should be:
    • Properly designed, constructed, and protected
    • From corrosion
    • Equipped with leak detection devices
    • Equipped with spill/overfill protection
    • Installed by a state certified installer
    • Inspected by a state certified inspector during installation
    • Registered with state upon installation.
  • Record keeping is necessary to ensure compliance with the federal, state, and local regulations. Records of a tank system should be maintained for the operating life of the system and at least 5 years after its permanent closure. The original documents should be maintained on site, if possible. The following records are often necessary to document appropriate environmental stewardship: [N]
    • Inventory Records
    • Installation Details
    • Modification/Repair Details
    • Operation Records
    • History of usage
    • Physical inspection checklists/reports
    • Monitoring records
    • Leak/incident documentation
    • Tank Handling Activity Report
    • Legal Records
    • Permits, notifications, and certificates
    • Agency correspondence
    • Consultant/Contractor Reports
    • Engineering assessments/surveys
    • Tank and line testing results
    • Environmental sampling results
    • UST Inspection Report
    • Tank Closure Records
    • UST Closure Notification Form
    • UST Closure Report Form
    • Registration of Storage Tank Form
    • Notification of Reportable Release/Notification of Contamination
  • Prior to releasing rainwater from secondary/ spill containment of an AST, inspect the water for contamination. If there is evidence of spilled or leaked material, or captured rainwater in the spill containment exhibits a surface sheen, contact the District Stormwater Coordinator or District Hazmat Manager for appropriate actions to be taken.
  • Make sure the drain valve or plug is properly secured to contain any future leaks or spills.
  • Be prepared to respond in the event of a leak or spill from an above ground tank:
    • Maintain an appropriate spill kit near each above ground tank.
    • Replenish spill kit supplies as they are used.
    • If the type of material being stored changes, replace spill kit contents with supplies appropriate for the new material.
  • For cleaning spilled materials, particularly hazardous materials, follow procedures from the product MSDS (Material Safety Data Sheet) or the North American Emergency Response Guidebook (Federal DOT document).
  • For facility-specific procedures related to spills, refer to the Spill Prevention Control and Countermeasures (SPCC) Plan, Title 40, Code of Federal Regulation, part 112 or the Hazardous Materials Business Plan.


6.5.1 Vehicle and Equipment Fueling Procedures and Practices
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Vehicle and equipment fueling procedures and practices are designed to minimize or eliminate the discharge of fuel spills and leaks into stormwater drainage systems or watercourses during equipment fueling and the bulk delivery of fuel. [N]

Bulk Fuel Delivery

  • All aboveground and underground storage tanks should be equipped with automatic overfill shutoff valves.
  • Spill Prevention and Control BMPs should be implemented to prevent spillage.

Fueling Area Maintenance

  • Label drains at fuel dispensing areas to indicate if they discharge to the storm drain or to the sewer.
  • Storm drain inlets may be temporarily covered with spill pads and/or mats during fueling operations.
  • Absorbent spill cleanup materials or drip pans should be stored in fueling and maintenance areas and used materials should be disposed in accordance with hazardous waste management BMPs.
  • Immediately clean up leaks and drips.
  • Hosing off the fueling area is prohibited. Dry shop clean up practices should be used.
  • Manage wastes to reduce adverse impacts on stormwater quality. Fueling areas should be kept free of litter and debris that might become contaminated with petroleum products.
  • Maintain and implement a current spill response plan for fueling operations.
  • Inspect fueling facilities daily and correct deficiencies.
  • Keep a supply of spill cleanup materials on site.

Refueling Practices

  • Fueling operations should not be left unattended. Fueling in the field should not be performed near unprotected drainage facilities or watercourses. See Spill Prevention and Control BMPs.
  • Drip pans should be used during vehicle and equipment fueling unless the fueling is performed over an impermeable surface in a dedicated fueling area. Dedicated fueling areas should be protected from stormwater run-on and runoff and should be located at least 15m from downstream drainage facilities or watercourses.
  • Nozzles used in vehicle and equipment fueling should be equipped with an automatic shutoff to control drips.
  • Warnings against "topping off" fuel tanks should be posted at fuel dispensers.
  • Fueling operations should not be left unattended.
  • Absorbent spill cleanup materials should be available in fueling and maintenance areas and should be disposed properly after use.
  • Vehicles and equipment leaks should be inspected and cleaned up on each day of use.
  • Leaks should be repaired immediately or problem vehicles or equipment should be removed from the project site.

A SPCC Plan outlining procedures and measures to prevent and respond to a petroleum spill is required if:

  • The underground tanks at the facility can store more than 42,000 gallons
  • 660 gallons or more can be stored in a single aboveground tank
  • 1,320 gallons or more can be stored in some combination of smaller aboveground tanks,
  • Portable containers (i.e., drums), and oil filled equipment or transformers.


6.5.2 Stewardship Practices for Known or Suspected Groundwater Contamination On-Site
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The potential for groundwater contamination raises the need for action at a site to a high priority level. The RCRA environmental indicator for controlling migration of contaminated groundwater requires the following documentation: [N] [N]

  • Consideration of all available, relevant or significant information on known and suspected releases to the groundwater at the facility;
  • Determination whether groundwater is contaminated above appropriately protective levels (i.e., applicable promulgated standards, other appropriate standards, guidelines, guidance, or criteria) anywhere at, or from, the facility;
  • Determination whether the migration of contaminated groundwater has stabilized (remains within the previously determined existing area of contamination);

Environmental stewardship of suspected groundwater contamination from runoff at maintenance sites or other DOT facilities should include the following, which parallel environmental indicators used by EPA to measure progress toward groundwater remediation at RCRA sites subject to corrective action. [N]

  • Where groundwater contamination is known or suspected, the DOT controls the migration of contaminated groundwater plumes, through:
    • Consideration of all available, relevant or significant information on known and suspected releases to the groundwater at the facility.
    • Determination whether groundwater is contaminated above appropriately protective levels (i.e., applicable promulgated standards, other appropriate standards, guidelines, guidance, or criteria) anywhere at, or from, the facility.
    • Determination whether the migration of contaminated groundwater has stabilized (remains within the previously determined existing area of contamination).
    • Determination whether contaminated groundwater discharges to surface water.
    • Determination whether any discharge of contaminated groundwater to surface water is "significant" (the maximum concentration of the contaminant in the surface water is more than ten times the appropriate groundwater level).
    • Determination whether the discharge of contaminated groundwater into surface water is "acceptable" until a full assessment and a final remedy decision can be made. Factors to be considered in the interim assessment include surface water body size, flow, use/classification/habitats, contaminant loading limits, other sources of surface water/sediment contamination, effects on ecological receptors (e.g., via bio-assays, benthic surveys or site specific ecological risk assessments performed by trained specialists).
    • Decision whether groundwater monitoring measurement data and surface water/sediment/ecological data will be collected in the future to verify that contaminated groundwater has remained within the existing area of contaminated groundwater.
  • Where groundwater contamination is known or suspected, the DOT controls human exposure to contaminated groundwater, through:
    • Consideration of all available relevant or significant information on known and suspected releases to soil, groundwater and surface water at the facility.
    • Determination whether the soil, groundwater or surface water is contaminated above appropriately protective risk-based levels.
    • Determination whether there are complete pathways between contamination and human receptors such that exposures can be reasonably expected under the current land, groundwater and surface water use conditions.
    • Determination whether the exposures resulting from the complete pathways (above) are "significant." Here, "significant" means: 1) greater in magnitude (intensity, frequency and/or duration) than assumed in the derivation of the "acceptable levels" used to identify the contamination, or 2) the combination of exposure magnitude (perhaps though low) and contaminant concentrations ( which may be substantially above the "acceptable levels" ) that could result in greater than acceptable risk.
  • The design and implementation of Best Management Practices is a DOT priority at sites where contaminated groundwater is suspected, in order to prevent further degradation and, possibly, migration to surface water, including sources of drinking water.

This documentation meets or exceeds that required by the Phase I Environmental Site Assessment Standard (ASTM E 1527-00), which may be utilized at some sites, and can serve as the foundation for further, Phase II investigations of "recognized environmental conditions" (RECs) identified during Phase I assessments.


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Continue to Section 7.1»
Table of Contents
Chapter 6
Maintenance Facilities Management
6.1 Planning and Prioritizing Environmental Improvements at Maintenance Facilities
6.2 Facility Housekeeping Practices
6.3 Yard and Floor Drain Management
6.4 Energy Conservation
6.5 Under and Above-Ground Storage Tanks
Lists: Examples | Tables | Figures
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