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Underground Storage Tanks (USTs)

Resources for UST Owners and Operators

Introduction

Release Prevention

EPA designed part of the technical regulations for underground storage tank (UST) systems to prevent releases from USTs. The regulations require owners and operators to properly install UST systems and protect their USTs from spills, overfills, and corrosion and require correct filling practices to be followed. In addition, owners and operators must report the existence of new UST systems, suspected releases, UST system closures, and keep records of operation and maintenance.

Release Detection

Because detecting UST systems releases quickly helps stop contamination before it spreads from UST sites, EPA requires owners and operators detect releases from their UST systems. EPA allows three categories of release detection: interstitial, internal, and external. These three categories include seven release detection methods.

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Financial Responsibility

What are financial responsibility requirements?

When Congress amended Subtitle I of the Solid Waste Disposal Act, it directed EPA to develop financial responsibility regulations for owners and operators of underground storage tanks.

Congress wanted owners and operators of underground storage tanks (USTs) to show that they have the financial resources to clean up a site if a release occurs, correct environmental damage, and compensate third parties for injury to their property or themselves. The amount of coverage required depends on the type and size of the business, as explained in the chart below. EPA produced a 16-page booklet called Dollars And Sense that clearly presents these requirements to UST owners and operators.

How can owners and operators demonstrate financial responsibility?

Owners and operators have several options:

  • Obtain insurance coverage from an insurer or a risk retention group
  • Demonstrate self-insurance using a financial test
  • Obtain corporate guarantees, surety bonds, or letters of credit
  • Place the required amount into a trust fund administered by a third party
  • Rely on coverage provided by a state financial assurance fund

Local governments have four additional compliance mechanisms tailored to their special characteristics:

  • A bond rating test
  • A financial test
  • A guarantee
  • A dedicated fund

What are the most commonly used financial assurance mechanisms?

Have compliance deadlines passed?

Yes. All of the compliance deadlines for financial responsibility have passed. All USTs that have not been permanently closed must currently meet the financial responsibility requirements.

What are the required coverage amounts?

The table below presents required amounts of financial responsibility for groups of UST owners and operators.

Required Amounts Of Financial Responsibility

Group of UST Owners and Operators Per Occurrence Coverage Aggregate Coverage
Group 1:

Petroleum producers, refiners, or marketers

$1 million $1 million for 100 or fewer tanks
or
$2 million for more than 100 tanks
Group 2:

Nonmarketers

$500,000 if throughput is 10,000 gallons monthly or less
or
$1 million if throughput is more than 10,000 gallons monthly

EPA's publication, Financial Responsibility for Underground Storage Tanks: A Reference Manual, provides information regarding the restrictions, limitations, and requirements of each financial responsibility mechanism under the federal UST regulations. Note that this reference manual is based on the federal UST financial responsibility requirements, though it should provide useful information and insight into understanding and reviewing state-specific financial responsibility mechanisms.

Why do states have funds?

Many states developed financial assurance funds to help owners and operators meet financial responsibility requirements and to help cover the costs of cleanups.

Operating and Maintaining UST Systems

In 2015, EPA revised the underground storage tank (UST) regulations. Below you will find the requirements for inspections and testing.

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Corrosion Protection

All cathodic protection systems: Owners and operators must have a periodic test conducted by a qualified cathodic protection tester to make sure the cathodic protection system is adequately protecting the UST system.  This test must be conducted:

  • Within six months of installation
  • At least every three years after the previous test 
  • Within six months of any repair to the UST system

Owners and operators must make sure the cathodic protection tester is qualified to perform the test and follows a standard code of practice to determine that test criteria are adequate.  If any test indicates your tanks are not adequately protected, you must have a corrosion expert examine and fix your system.

Keep records of the most recent two cathodic protection tests.

Impressed current cathodic protection systems: Owners and operators must inspect the rectifier at least every 60 days to make sure that it is operating within normal limits.

  • This inspection involves reading and recording the voltage and amperage readouts on the rectifier.  Owners and operators can perform this periodic inspection.
  • Owners and operators need to make sure the corrosion expert provided the rectifier’s acceptable operating levels so owners and operators can compare the readings to make sure they are within acceptable operating levels.  If readings are not within acceptable levels, contact a corrosion expert to address the problem.

Keep records of at least the last three rectifier readings.

Internally lined tanks: Owners and operators of internally lined tanks must have the lined tank inspected by a trained professional to determine if the lined tank is structurally sound with the lining still performing according to original design specifications.  The lining inspection must follow a standard code of practice.  The inspections must occur within 10 years after lining and then at least every 5 years thereafter.  Keep a record of the internal lining inspection as required by the standard code of practice used for the lining inspection.  If owners and operators use both an internal lining and cathodic protection for their UST system and the steel tank was assessed and determined to be structurally sound and free of corrosion holes before adding the cathodic protection, then periodic inspections of the lining are not required.


Walkthrough Inspections

Beginning on October 13, 2018 owners and operators must conduct walkthrough inspections at their UST facility. The walkthrough inspection must meet one of the following:

Option 1: Every 30 days (except spill prevention equipment at UST systems receiving deliveries at intervals greater than every 30 days may be checked prior to each delivery), check your spill prevention equipment and release detection equipment. Annually, check your containment sumps and any hand held release detection equipment.

When conducting the walkthrough inspection, check the following:

  • Spill prevention equipment
    • Check for damage
    • Remove any liquid or debris
    • Check for and remove any obstructions in the fill pipe
    • Check the fill cap to make sure it is securely on the fill pipe
    • Double walled spill prevention equipment with interstitial monitoring check for a leak in the interstitial area
  • Release detection equipment
    • Ensure it is operating with no alarms or other unusual operating conditions present
    • Ensure records of release detection testing are reviewed and current
  • Containment sumps
    • Check for damage, leaks into the containment area, or releases to the environment
    • Remove any liquid or debris
    • Double walled containment sumps with interstitial monitoring check for a leak in the interstitial area
  • Hand held release detection equipment (for example tank gauge sticks or ground water bailers)
    • Check for operability and serviceability

Option 2: Conduct walkthrough inspections according to a standard code of practice developed by a nationally recognized association or independent testing laboratory. The code of practice must check equipment comparable to option 1 above.

Option 3: Conduct walkthrough inspections according to requirements developed by your implementing agency. These requirements must be comparable to the requirements described in option 1 above.

In addition to these requirements, owners and operators must inspect the following additional areas for airport hydrant systems at least once every 30 days if confined space entry according to the Occupational Safety and Health Administration is not required or at least annually if confined space entry is required.

  • Hydrant pits – Check for any damage; remove any liquid or debris; and check for any leaks
  • Hydrant piping vaults – Check for any hydrant piping leaks

Owners and operators must maintain the most recent year’s walkthrough inspection records. Records need to include a list of each area checked, whether each area checked was acceptable or needed action taken, a description of any actions taken to correct issues, and delivery records if spill prevention equipment is checked less frequently than every 30 days due to infrequent deliveries.

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Overfill Prevention Equipment Inspections

Beginning on October 13, 2018 owners and operators must have their overfill prevention equipment inspected for proper operation at least once every three years. Overfill prevention equipment installed after October 13, 2015 must be inspected for proper operation at installation and then once every three years. Note that most installation codes of practice require inspecting overfill prevention equipment at installation – this would qualify as the first inspection. When inspecting, owners and operators must at a minimum ensure the overfill prevention equipment is set to activate at the correct level in the tank (the level depends on the type of overfill device) and will activate when regulated substances reach that level.

Overfill prevention equipment must be inspected according to one of the following:

  • Requirements developed by the manufacturer (owners and operators may only use this option if the manufacturer has developed inspection requirements)
  • A code of practice developed by a nationally recognized association or independent testing laboratory
  • Requirements determined by the implementing agency to be no less protective than those developed by the manufacturer or in the code of practice

Owners and operators must maintain records of overfill prevention equipment inspections for at least three years.

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Spill Prevention Equipment and Containment Sump Testing

Beginning on October 13, 2018 owners and operators must meet one of the following for spill containment equipment and for containment sumps used for piping interstitial monitoring:

Option 1: Spill prevention and containment sump equipment is double walled and the integrity of both walls is monitored at least as frequently as in the walkthrough inspection requirement (typically every 30 days for spill buckets but it may be longer if the facility receives infrequent deliveries, and annually for containment sumps). If owners and operators discontinue this periodic monitoring, they have 30 days to conduct the test described in option 2 below.

Option 2: Spill prevention equipment and containment sumps used for interstitial monitoring of piping are tested at least once every three years. The test must determine the equipment is liquid tight by using either vacuum, pressure, or liquid testing according to one of the following:

  • Requirements developed by the manufacturer (owners and operators may only use this option if the manufacturer has developed testing requirements)
  • A code of practice developed by a nationally recognized association or independent testing laboratory
  • Requirements determined by the implementing agency to be no less protective than those developed by the manufacturer or in the code of practice

Owners and operators must maintain records of spill prevention equipment and containment sump testing for at least three years. For spill prevention equipment and containment sumps used for interstitial monitoring of piping not tested every three years, owners and operators must maintain documentation showing the equipment is double walled and the integrity of both walls is periodically monitored for as long as the equipment is periodically monitored.

Spill prevention equipment and containment sumps used for interstitial monitoring of piping installed after October 13, 2015 must be tested for liquid tightness at installation and then once every three years. Note that most installation codes of practice require testing of this equipment for liquid tightness at installation – this would qualify as the first test.

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Release Detection Equipment Testing

Beginning on October 13, 2018 owners and operators must test electronic and mechanical components of their release detection equipment for proper operation at least annually using one of the following options:

  • Manufacturer’s instructions
  • A code of practice developed by a nationally recognized association or independent testing laboratory
  • Requirements developed by the implementing agency

When testing, check the following:

  • Automatic tank gauge and other controllers
    • Test the alarm
    • Verify the system configuration
    • Test the battery backup
  • Probes and sensors
    • Inspect for residual buildup
    • Ensure any floats move freely
    • Ensure any shafts are not damaged
    • Ensure the cables are free of kinks and breaks
    • Test the alarm operability and communication with the controller
  • Automatic line leak detector
    • Ensure the device activates (alarms, restricts flow, or shuts off flow) within an hour when simulating a release equivalent to 3 gallons per hour at 10 pounds per square inch
  • Vacuum pumps and pressure gauges
    • Ensure there is proper communication with sensors and the controller
  • Hand-held electronic sampling equipment associated with ground water and vapor monitoring
    • Ensure the device operates properly

Owners and operators must maintain records of release detection equipment testing for at least three years. The record must include each component tested, whether each component passed the test or needed to have action taken, and any action taken to correct an issue.

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Reporting and Recordkeeping

In 2015, EPA revised the underground storage tank (UST) regulations. Below you will find reporting and recordkeeping requirements.

Below are the federal reporting and recordkeeping requirements. You should check with your implementing agency (typically your state or local regulatory authority) about particular reporting and recordkeeping requirements in your area.

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What Do You Need To Report?

You need to report to your implementing agency or EPA when UST systems are located in Indian country on the following occasions:

  • When you install an UST, you have to fill out a notification form and submit it to your implementing agency within 30 days of bringing the UST system into use. This form provides information about your UST, including a certification of correct installation. (You should have already used this form to identify your existing USTs. If you haven't done that yet, be sure you do so now.)
  • 2015 Requirement: Beginning on October 13, 2015 when you assume ownership of an UST system, you must fill out a notification of ownership change form and submit it to your implementing agency within 30 days of acquiring the UST system.
  • 2015 Requirement: Beginning on October 13, 2015 you must notify the implementing agency at least 30 days before you switch to a regulated substance containing greater than 10 percent ethanol, greater than 20 percent biodiesel, or any other regulated substance identified by the implementing agency.
  • 2015 Requirement: Not later than October 13, 2018 owners of airport hydrant systems and field-constructed tanks must submit a one-time notification of existence for these UST systems using the notification form.
  • You must report suspected releases to your implementing agency. If a release is confirmed, you must also report follow-up actions you plan or have taken to correct the damage caused by your UST.
  • You must notify your implementing agency 30 days before you permanently close your UST.

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What Records Must You Keep?

You will have to keep records that can be provided to an inspector during an on-site visit that prove your facility meets certain requirements. These records must be kept as follows:

  • You will have to keep records of leak detection performance and maintenance:
    • The last year's monitoring results, and the most recent tightness test.
    • Copies of performance claims provided by leak detection manufacturers must be kept for five years.
    • Records of recent maintenance, repair, and calibration of on-site leak detection equipment.
    • 2015 Requirement: Beginning on October 13, 2018 keep records of annual release detection equipment operations tests for three years.
    • 2015 Requirement: Beginning on October 13, 2018 keep records of site assessments for groundwater and vapor monitoring methods for as long as the methods are used.
    • 2015 Requirement: Beginning on October 13, 2018 keep the most recent tank tightness test, piping tightness test and vapor monitoring result using a tracer compound for airport hydrant systems and field-constructed tanks.
  • You will have to keep records of the last three 60 day rectifier inspections and the last two three year tests of your corrosion protection system.
  • If corrosion protection equipment is not used for metal tanks and piping, you must keep a record of the corrosion expert’s analysis of the site corrosion potential for the life of the UST system.
  • You must keep records showing that a repaired or upgraded UST system was properly repaired or upgraded until the UST system is permanently closed or undergoes a change-in-service.
  • For at least 3 years after closing an UST, you must keep records of the site assessment results required for permanent closure. (These results show what impact your UST has had on the surrounding area.)
  • You must keep records that document your financial responsibility, as explained in EPA's booklet, Dollars And Sense.
  • 2015 Requirement: Beginning on October 13, 2015 keep records demonstrating compliance with the compatibility requirement if storing regulated substances containing greater than 10 percent ethanol, greater than 20 percent biodiesel or any other regulated substance identified by the implementing agency, for as long as the UST system is used to store the regulated substance.
  • 2015 Requirement: Beginning on October 13, 2018 keep records of spill bucket testing, containment sump testing, and overfill inspections for three years. If spill bucket or containment sump testing is not conducted, keep documentation showing the equipment is double walled and the integrity of both walls is periodically monitored for as long as testing is not conducted.
  • 2015 Requirement: Beginning on October 13, 2018 keep records of walkthrough inspections for one year.
  • 2015 Requirement: Beginning on October 13, 2018 keep records of demonstrating compliance with the operator training requirements.

The preceding discussion is summarized from the regulatory language in 40 CFR Part 280.34.

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Tank and Piping Installation

In 2015, EPA revised the underground storage tank (UST) regulations. Below you will find the requirements for tank and piping installation.

If you install an UST system after December 22, 1988, it must be properly installed according to a code of practice developed by a nationally recognized association or independent testing laboratory and according to the manufacturer’s instructions (40 CFR Part 280.20(d)). Some states may require that UST installers be certified (in addition to being qualified) to conduct this type of work. You should check with your implementing agency to be sure that you follow the appropriate regulations.

2015 requirement for secondary containment and under-dispenser containment – Beginning on April 11, 2016 all new and replaced tanks and piping must meet the secondary containment requirements, including interstitial monitoring, according to the 2015 requirements for secondary containment. EPA considers piping replaced when 50 percent or more of the piping is removed and other piping is installed. In addition, beginning on April 11, 2016 new dispenser systems must have under-dispenser containment.

Installation includes excavation, tank system siting, burial depth, tank system assembly, backfilling around the tank system, and surface grading. Many mistakes can be made during installation. For example, mishandling of the tank during installation can cause structural failure of fiberglass-reinforced plastic tanks or damage to steel tank coatings and cathodic protection. Improper layout of piping runs, incomplete tightening of joints, inadequate cover pad construction, and construction accidents can lead to failure of piping.

You need to make sure that installers carefully follow the correct installation procedures called for by industry codes and follow manufacturer’s instructions.

In addition, federal regulations (40 CFR Part 280.20 (e)) require that owners and operators ensure one or more of the following methods of certification, testing, or inspection is used to demonstrate compliance with the installation requirements by providing a certification of compliance on the UST notification form.

  • the installer has been certified by the tank and piping manufacturers; or
  • the installer has been certified or licensed by the implementing agency; or
  • the installation has been inspected and certified by a registered professional engineer with education and experience in UST system installation; or
  • the installation has been inspected and approved by the implementing agency; or
  • all work listed in the manufacturer's installation checklists has been completed; or
  • the owner and operator have complied with another method for ensuring compliance with the installation requirements that is determined by the implementing agency to be no less protective of human health and the environment.

Closing and Replacing UST Systems

In 2015, EPA revised the underground storage tank (UST) regulations. Below you will find the requirements for closing USTs.

UST systems in use on or after December 22, 1998 must meet the closure requirements at 40 CFR 280.70 when an owner and operator decides to close the UST system. You can close your UST temporarily or permanently. In either case, USTs must be closed properly.

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Closing Temporarily

You may temporarily close your UST for up to 12 months by following these requirements:

  • Continue to maintain and monitor any corrosion protection systems
  • Continue to maintain financial responsibility
  • Beginning on October 13, 2018 your operators must be trained
  • If your temporarily closed UST is not empty, you must also:
    • Continue to monitor for leaks by performing release detection
    • Perform monthly walkthrough inspections for your release detection beginning on October 13, 2018
    • Perform annual inspections and testing of release detection equipment beginning on October 13, 2018
    • Perform three year containment sump testing if using the containment sump for interstitial monitoring of the piping beginning on October 13, 2018
  • If a release is discovered, quickly stop the release, notify your regulatory authority, and take appropriate action to clean up the site.
  • If the UST remains temporarily closed for more than 3 months, leave vent lines open, but cap and secure all other lines, pumps, manways, and ancillary equipment.

USTs in temporary closure are not required to meet the following requirements:

  • Spill testing
  • Overfill Inspections
  • Empty USTs do not require:
    • Release detection
    • Annual release detection testing and inspections
    • Monthly walkthrough inspections
    • Three year containment sump testing

An UST is considered empty if no more than one inch of residue is present or not more than 0.3 percent by weight of the total capacity of the UST system remains in the system.

After 12 months of temporary closure, you have three options:

  • You must permanently close your UST if it doesn't meet the applicable requirements for new or upgraded USTs (except for spill and overfill).
  • You can ask your implementing agency for an extension beyond 12 months, if you provide an assessment that determines whether contamination is present at your site.
  • Your UST can remain temporarily closed without needing an extension granted by the implementing agency if the UST meets the applicable requirements for new or upgraded USTs (except for spill and overfill) and the requirements noted above for temporary closure.

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Closing Permanently

If you decide to close your UST permanently, follow these requirements for permanent closure:
  • Notify the implementing agency at least 30 days before you close your UST.
  • Determine if contamination from your UST is present in the surrounding environment. If there is contamination, you may have to take corrective action. For at least 3 years, keep a record of the actions you take to determine if contamination is present at the site (or you can mail this record to your implementing agency).
  • Either remove the UST from the ground or leave it in the ground. In both cases, the tank must be emptied and cleaned by removing all liquids, dangerous vapor levels, and accumulated sludge. These potentially very hazardous actions need to be carried out carefully by trained professionals who follow standard safety practices. If you leave the UST in the ground, have it filled with a harmless, chemically inactive solid, like sand, or close it in place in a manner approved by the implementing agency. 

Don't forget to check with your implementing agency for their closure requirements.

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Safe Closure is a Must

People who do not follow standard safety practices are killed or injured every year while closing or removing tanks. For a safe closure, you need qualified professionals who will use standard safety practices.

For more information on standard safety practices, UST owners and closure contractors should refer to "Closure of Underground Petroleum Storage Tanks," API Recommended Practice 1604 (1996), which is available from the American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005, or call (202) 682-8000 for assistance. You can also visit API's website Exit.

The video and companion booklet called "Tank Closure Without Tears: An Inspector's Safety Guide" are available from the New England Interstate Environmental Training Center at (978) 323-7929. You can also visit NEIWPCC's website Exit.

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