Secondary containment

• Secondary containment is a primary way to prevent discharge into the environment from ASTs and USTs.
• There are two types of secondary containment: passive secondary containment and active secondary containment.

One of the primary ways to prevent discharges from both aboveground storage tanks (ASTs) and underground storage tanks (USTs) into the environment is by using secondary containment. Secondary containment provides temporary containment of a spilled chemical or waste if the primary container (such as a bulk storage container, a mobile or portable container, piping, or plant equipment) fails. It gives a facility time to abate the source of the discharge and remove the accumulated substance to prevent it from reaching nearby waterbodies or soil.

Secondary containment may be divided into two types:

• Passive secondary containment. Installations that do not require deployment or action by the facility owner or operator but remain in place regardless of the facility operations are forms of passive secondary containment. Examples include dikes, berms, retaining walls, curbing, culverting, gutters, drainage, weirs, booms, barriers, diversion, retention ponds, drip pans, sumps, and collection systems.
• Active secondary containment. Measures that require deployment or other specific action by the facility owner or operator before or after a discharge occurs are examples of active secondary containment, also often referred to as spill countermeasures. Examples include placing a storm drain cover over a drain prior to chemical transfers or in reaction to a discharge, using nearby spill kits with absorbent materials, building emergency structures in the event of a discharge, and closing a gate valve to control drainage.

Although secondary containment systems are preferred, they may not always be practicable. If a professional engineer determines that containment methods are impracticable, alternative modes of protection to prevent and contain discharges are available, such as:

• Periodic integrity testing of storage containers;
• Periodic integrity testing and leak testing of the valves and piping associated with storage containers;
• A spill contingency plan; and
• A commitment of workforce, equipment, and materials required to expeditiously control and remove any quantity of chemical discharged that may be harmful.

Secondary containment regulations may:

• Call for passive secondary containment;
• Allow for passive or active secondary containment; and/or
• Allow for alternatives to secondary containment to prevent released material from reaching waterbodies.

Secondary containment regulations could also, for example, require:

• Specific sizing (volume) for either a worst-case discharge (e.g., construction of secondary containment sized to contain a discharge from the largest container) or a typical discharge incident (based on a most-likely scenario);
• Design specifications to address passive or active measures, impermeability of containment structures, and freeboard for precipitation;
• Maintenance provisions, including inspections to ensure the designed capacity is maintained (e.g., by removing rainwater or other debris); and
• Corrective actions to ensure that inspection results are addressed.

Requirements for AST systems

• It is necessary to look in several different places for AST requirements.

At the federal level, aboveground storage tanks (ASTs) are regulated in a somewhat piecemeal way. Consequently, it is necessary to look in several different places for AST requirements.

• Concerning the storage of hazardous waste in ASTs, owners and operators must look in the hazardous waste regulations (40 CFR Parts 260 through 268) to determine what is required. Parts 262, 264, and 265 of the Resource Conservation and Recovery Act (RCRA), Subtitle C, also impact ASTs as these requirements apply to hazardous waste generators and treatment, storage, and disposal facilities.
• If owners and operators store oil in an AST, they may be regulated under the Spill Prevention, Control and Countermeasure (SPCC) regulations at 40 CFR Part 112. The SPCC regulations establish procedures to prevent the discharge of oil into navigable waters.
• Some ASTs fall under Occupational Safety and Health Administration (OSHA) requirements if they contain flammable or combustible liquids. The rules apply to liquids with flashpoints below 200°F. In this case, the objective of the regulations is to protect workers from fires, rather than protecting the environment from spills.

The majority of regulations affecting ASTs are found at the state and local level. Check with state and local agencies to see if there are more stringent AST requirements that need to be followed.

Basic requirements for UST systems

• The greatest potential hazard from a leaking UST is that hazardous substance can seep into the soil and contaminate groundwater.
• Various basic compliance requirements are needed for USTs.

An underground storage tank (UST) system is a tank, and any underground piping connected to the tank, that has at least 10 percent of its combined volume underground. The federal UST regulations apply only to underground tanks and piping storing either petroleum or certain hazardous substances.

Until the mid-1980s, most USTs were made of bare steel, which is likely to corrode over time and allow UST contents to leak into the environment. Faulty installation or inadequate operating and maintenance procedures also can cause USTs to release their contents into the environment. The greatest potential hazard from a leaking UST is that the petroleum or other hazardous substance can seep into the soil and contaminate groundwater, a major source of drinking water. A leaking UST can present other health and environmental risks, including the potential for fire and explosion.

Cited under 40 CFR 280-282, the basic compliance requirements are:

• Properly install USTs.
• Ensure tanks have required secondary containment and corrosion protection.
• Follow correct filling practices.
• Report new UST systems, suspected and confirmed releases, and UST system closures.
• Keep accurate records of operation and maintenance.
• Ensure Class A and B operators have correct training and pass required exams.
• Ensure Class C operators have correct training.

Financial responsibility regulations for USTs

• Owners must keep a current “Certification of Financial Responsibility,” and any additional documentation that shows the owner’s financial responsibility method is valid and provides details on the method’s coverage at the UST site or place of business.
• Many states have developed financial assurance funds to reduce the economic hardship of compliance with financial responsibility requirements and to help cover the costs of cleanups.

The financial responsibility regulations for underground storage tanks (USTs) ensure that, in the event of a leak or spill, an owner or operator will have the resources to pay for costs associated with cleaning up releases, correcting environmental damage, and compensating third parties for injury to their property or themselves.

The amount of coverage required depends on the type and size of the business, as summarized in the following table.

How to demonstrate financial responsibility

There are several ways to demonstrate financial responsibility:

• Use state financial assurance funds. The state may pay for some cleanup and third-party liability costs.
• Obtain insurance coverage. Insurance may be available from a private insurer or a risk retention group.
• Obtain a guarantee. Secure a guarantee for the coverage amount from another firm. The provider of the guarantee must pass a financial test.
• Obtain a surety bond. A surety bond is a guarantee by a surety company that it will meet the UST owner’s financial responsibility obligations.
• Obtain a letter of credit. A letter of credit is a contract involving the UST owner, an issuer (usually a bank), and a third party (such as the implementing agency) that obligates the issuer to help demonstrate financial responsibility.
• Set up a trust fund. A UST owner may set up a fully funded trust fund administered by a third party to demonstrate financial responsibility.
• Use other state methods. A UST owner may also use any additional methods of coverage approved by the state.

Local governments may have four additional compliance methods: a bond rating test, a financial test, a guarantee, and a dedicated fund.

Records of financial responsibility coverage

Owners must keep at the UST site or place of business the following records of financial responsibility coverage:

• A current “Certification of Financial Responsibility,” the required wording of which can be found at 40 CFR 280.111.
• Any additional documentation that shows the owner’s financial responsibility method is valid and provides details on the method’s coverage, such as signed copies of official letters, policies, and state fund agreements.

Records must be kept until the UST site is properly closed. In addition, many states require copies of financial responsibility records be filed with the state agency. The Environmental Protection Agency (EPA) does not require UST owners to report financial responsibility records unless it specifically asks them to do so.

How state financial assurance funds help

Many states have developed financial assurance funds to reduce the economic hardship of compliance with financial responsibility requirements and to help cover the costs of cleanups. State financial assurance fund programs, which supplement or are a substitute for private insurance, have been especially useful for small-to-medium sized petroleum marketers. Other characteristics of the funds include the following:

• Financial assurance funds are created by state legislation and must be submitted to EPA for approval before they can be used as compliance mechanisms.
• In most cases, states generate money for the funds with tank registration and petroleum fees.
• Legislatures delegate authority for the fund to a state agency addressing health, environmental, or insurance issues.
• Some state assurance funds incorporate eligibility requirements, such as demonstrations that facilities are in compliance with technical requirements.
• Most state funds contain some deductible that the owner or operator is responsible for paying, the details of which are state-specific.

Operation and maintenance of UST systems

• UST systems must be designed, constructed, and installed in accordance with industry codes and standards and according to manufacturer’s instructions.
• Owners and operators must use a UST system made of or lined with materials that are compatible with the substance stored in the system.

Proper underground storage tank (UST) management includes regular performance of operation and maintenance duties. Beyond ensuring proper compatibility and installation, these duties include operation and maintenance of corrosion protection as well as ensuring that correct filling procedures are followed.

UST systems must also be designed, constructed, and installed in accordance with industry codes and standards and according to manufacturer’s instructions. Find a list of industry codes and standards at www.epa.gov/oust/cmplastc/standard.htm.

Compatibility

Owners and operators must use an underground storage tank (UST) system made of or lined with materials that are compatible with the substance stored in the UST system.

Owners and operators must notify the implementing agency at least 30 days prior to switching 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. In addition, owners and operators with UST systems storing these regulated substances must meet one of the following:

• Demonstrate compatibility of the UST system (including the tank, piping, containment sumps, pumping equipment, release detection equipment, spill equipment, and overfill equipment by using one of the following options:
  • Certification or listing of UST system equipment or components by a nationally recognized, independent testing laboratory for use with the regulated substance stored; or
  • Equipment or component manufacturer approval, which must be in writing, indicate an affirmative statement of compatibility, and specify the range of biofuel blends the equipment or component is compatible with; or
  • Use another option determined by the implementing agency to be no less protective of human health and the environment than the options listed above.
• Maintain records documenting compliance for as long as the UST system is used to store the regulated substance.

Preventing releases from USTs

• Many releases at UST sites come from spills.
• UST regulations require owners and operators to meet certain correct filling practices.

The Environmental Protection Agency (EPA) designed part of the technical regulations for underground storage tanks (USTs) to prevent releases from USTs. The regulations require USTs to be protected from spills, overfills, and corrosion, and to follow correct filling practices.

Correct filling practices

Many releases at UST sites come from spills; spills often occur at the fill pipe when the delivery truck’s hose is disconnected. Although these spills are usually small, repeated small releases can cause big environmental problems. Human error causes most spills; these mistakes can be avoided by following standard tank filling practices. The UST regulations require owners and operators to meet the following correct filling practices:

• Ensure the volume available in the tank is greater than the volume of regulated substance to be transferred to the tank before the transfer is made; and
• Ensure the transfer operation is monitored continuously.

The regulations refer to the transfer procedures described in National Fire Protection Association Standard 385, “Standard for Tank Vehicles for Flammable and Combustible Liquids” or American Petroleum Institute Recommended Practice 1007, “Loading and Unloading of MC 306/DOT 406 Cargo Tank Motor Vehicles.” Further guidance on spill and overfill prevention appears in American Petroleum Institute Recommended Practice 1621, “Bulk Liquid Stock Control at Retail Outlets.”

Spill cleanup

• EPA regulations require UST owners and operators to respond to a release by carrying out certain actions.
• A company should suspect a release when they observe unusual operating conditions and/or results from release detection monitoring and testing indicate a release.

Environmental Protection Agency (EPA) regulations require underground storage tank (UST) owners and operators to respond to a release by:

• Reporting a release;
• Removing its source;
• Mitigating fire and safety hazards;
• Investigating the extent of the contamination; and
• Cleaning up soil and groundwater as needed to protect human health and the environment.

The EPA developed the UST regulations and program to be flexible, and to be implemented by state and local agencies. Every state and many local governments now have active UST cleanup programs.

One of the EPA’s top priorities in the UST program is to help state and local governments make cleanups faster, cheaper, and more effective.

What to do if a release is suspected

Alarms and warning signals may indicate that an underground storage tank (UST) is leaking. A company can minimize damage to the environment, and to the business, by paying attention to early warning signals and taking immediate action before major problems develop.

A company should suspect a release when they observe these warning signals:

• Unusual operating conditions. Check first to see if the problem results from equipment failure that can be repaired. Be sure to remove any liquid from the interstitial space of secondarily contained systems.
• Results from release detection monitoring and testing indicate a release. What at first appears to be a release may be the result of faulty equipment that is part of the UST system or its release detection. Check this equipment carefully for failures.

If a company investigates an unusual operating condition or release detection alarm and determines a release has not occurred, the company does not need to report a suspected release as long as they immediately fix the problem. Otherwise, call the implementing agency and report the suspected release.

To find out quickly if the suspected release is an actual release, use these investigative steps:

• Conduct tightness testing or interstitial integrity testing of the entire UST system.
• Check the site for additional information on the presence and source of contamination.

If the system tests and site checks confirm that a release has occurred, follow the actions for responding to confirmed releases. Respond quickly to any evidence of released petroleum that appears at or near the site. For example, neighbors might tell the company they smell petroleum vapors in their basements or taste petroleum in their drinking water. Or the company may notice unusual operating conditions such as erratic behavior of the dispensing pump and liquid in the interstitial space of secondarily contained systems. If evidence of this type is discovered, report this discovery immediately to the implementing agency and take the required investigative steps and follow-up actions.

Closing underground storage tanks

• After 12 months of temporary closure, the company must permanently close the UST.
• Notify the implementing agency at least 30 days before permanently closing the UST.

Tank closure is one way to help protect human health and the environment, particularly groundwater, from the threats posed by many older underground storage tanks. The company can close the underground storage tank (UST) temporarily or permanently.

Temporary closings

The company may temporarily close the UST for up to 12 months by following these requirements:

• Continue to maintain and monitor corrosion protection systems;
• Continue to maintain financial responsibility;
• The company’s operators must be trained;
• If the temporarily closed UST is not empty, the company must also:
  • Continue to monitor for leaks by performing release detection,
  • Perform monthly walkthrough inspections for release detection,
  • Perform annual inspections and tests of release detection equipment, and
  • Perform three-year containment sump testing if using the containment sump for interstitial monitoring of the piping.
• If a release is discovered, quickly stop the release, notify the implementing agency, and take appropriate action to clean up the site;
• If the UST remains temporarily closed for more than three 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

A 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, the company must permanently close the UST. The company’s UST, however, can remain temporarily closed indefinitely if it meets the requirements for new or upgraded USTs, except that spill and overfill requirements do not have to be met, and the company meets the requirements above for temporarily closed USTs.

Permanent closings

Notify the implementing agency at least 30 days before permanently closing the UST.

In addition, the company must determine if contamination from the UST is present in the surrounding environment. If there is contamination, the company will have to take remedial action.

The company can 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 following standard safety practices. (See www.epa.gov/oust/cmplastc/standard.htm for a safe closure standard.)

If the company leaves the UST in the ground, they must also either fill it with a harmless, chemically inactive solid, like sand, or close it in place in a manner approved by the implementing agency.

The implementing agency can help the company decide how best to close the UST so that it meets local requirements for closure.

Recordkeeping requirements for USTs

• There are required records owners and operators must keep for various aspects of UST operation and maintenance on site.

Federal Environmental Protection Agency (EPA) requires underground storage tank (UST) owners and operators keep records to provide to during an inspection and to prove the facility meets certain requirements. States may have additional recordkeeping requirements. The following table lists the required records owners and operators must keep for various aspects of UST operation and maintenance on site.

UST recordkeeping requirements

Notification and reporting time frames for USTs

• Certain information must be reported at various times for major events in the operational life of a UST.

This table illustrates what must be reported—and when—for major events in the operational life of an underground storage tank (UST):

Operator training requirements for USTs

• Designate Class A, B, and C operators and train them on their UST responsibilities.
• Each UST system or group of UST systems at a facility must have a Class A, B, and C operator designated.

Designate Class A, B, and C operators and train them on their underground storage tank (UST) responsibilities. After that date, Class A and B operators must be trained within 30 days of assuming their duties. Class C operators must be trained before assuming their duties.

UST operator training means any program that meets the requirements of these guidelines. Such a program is designed to ensure knowledge regarding operating and maintaining underground storage tank systems.

Who is subject to operator training requirements?

The Environmental Protection Agency (EPA) added Subpart J to 40 CFR Part 280 to address the training requirements for underground storage tank (UST) operators. For purposes of implementing the operator training requirements, EPA established three classes of operators identified as Class A, B, and C. Each underground storage tank system or group of UST systems at a facility must have a Class A, B, and C operator designated. All individuals designated as a Class A, B, or C operator must, at a minimum, be trained according to their level of responsibility.

Separate individuals may be designated for each class of operator described above or an individual may be designated to more than one of the above operator classes. An individual who is designated to more than one operator class must be trained in each operator class for which the individual is designated.

States must establish a procedure to identify individuals who are required to meet the operator training requirements. For example, a state may require that UST system owners or operators identify, for each UST system or group of UST systems at a facility, at least one name for each class of operator.

There may be occasions when a Class A, B, or C operator will not be present at the facility. For example, operators are frequently not present at unmanned facilities, such as emergency generators at telecommunication towers and card lock/card access facilities. However, these operators are still responsible for operation and maintenance activities or responding to emergencies and must be trained.

Key definitions for secondary containment

• Secondary containment means temporary containment of a discharge if the primary container fails.

Double-walled tank: Essentially a tank within another tank, equipped with an interstitial (i.e., annular) space and constructed in accordance with industry standards. The inner tank serves as the primary storage container while the outer tank serves as secondary containment. The outer tank of a double-walled tank may provide adequate secondary containment for discharges resulting from leaks or ruptures of the entire capacity of the inner storage tank. Note: Double-walled tanks with fittings or openings (e.g., a manway) located below the liquid level of the container may require additional secondary containment to conform with industry standards and/or local codes. Moreover, a double-walled tank does not provide adequate secondary containment to address transfer-related overfills from the tank vent; therefore, secondary containment measures may be necessary to contain overfills from vents associated with transfer operations.

Secondary containment: Temporary containment of a discharge if the primary container fails. Secondary containment gives a facility time to abate the source of the discharge and remove the accumulated substance to prevent it from reaching waterbodies.

Storage capacity of a container: The shell capacity of the container.

Freeboard: Capacity of the secondary containment meant to hold precipitation above and beyond the capacity intended for a discharge from the largest single container. Note: Whether freeboard is “sufficient” is a matter of engineering practice that may depend on local precipitation conditions, height of the containment wall, size of the tank or container, safety considerations, and frequency of the secondary containment drainage and inspection.

Key definitions for USTs

• Certain terms are integral to understanding UST regulations.

Ancillary equipment: Any devices including (but not limited to) those such as piping, fittings, flanges, valves, and pumps used to distribute, meter, or control the flow of regulated substances to and from an underground storage tank (UST).

Cathodic protection: A technique to prevent corrosion of a metal surface by making that surface the cathode of an electrochemical cell. For example, a tank system can be cathodically protected through the application of either galvanic anodes or impressed current.

Cathodic protection tester: A person who can demonstrate an understanding of the principles and measurements of all common types of cathodic protection systems as applied to buried or submerged metal piping and tank systems. At a minimum, such persons must have education and experience in soil resistivity, stray current, structure-to-soil potential, and component electrical isolation measurements of buried metal piping and tank systems.

Connected piping: All underground piping including valves, elbows, joints, flanges, and flexible connectors attached to a tank system through which regulated substances flow. For the purpose of determining how much piping is connected to any individual UST system, the piping that joins two UST systems should be allocated equally between them.

Containment sump: A liquid-tight container that protects the environment by containing leaks and spills of regulated substances from piping, dispensers, pumps, and related components in the containment area. Containment sumps may be single walled or secondarily contained and located at the top of tank (tank top or submersible turbine pump sump), underneath the dispenser (under-dispenser containment sump), or at other points in the piping run (transition or intermediate sump).

Corrosion expert: A person who, by reason of thorough knowledge of the physical sciences and the principles of engineering and mathematics acquired by a professional education and related practical experience, is qualified to engage in the practice of corrosion control on buried or submerged metal piping systems and metal tanks. Such a person must be accredited or certified as being qualified by the National Association of Corrosion Engineers or be a registered professional engineer who has certification or licensing that includes education and experience in corrosion control of buried or submerged metal piping systems and metal tanks.

Dispenser system: The dispenser (i.e., the equipment located aboveground that dispenses regulated substances) and the equipment necessary to connect the dispenser to the UST system.

Existing tank system: A tank system used to contain an accumulation of regulated substances or for which installation has commenced on or before December 22, 1988.

Hazardous substance UST system: An underground storage tank system that contains a hazardous substance defined in 101(14) of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980 (but not including any substance regulated as a hazardous waste under subtitle C) or any mixture of such substances and petroleum, and which is not a petroleum UST system.

Operational life: The period beginning when installation of the tank system has commenced until the time the tank system is properly closed.

Overfill release: A release that occurs when a tank is filled beyond its capacity, resulting in a discharge of the regulated substance into the environment.

Owner:

1. In the case of an UST system in use on November 8, 1984, or brought into use after that date, any person who owns an UST system used for storage, use, or dispensing of regulated substances; and
2. In the case of any UST system in use before November 8, 1984, but no longer in use on that date, any person who owned such UST immediately before the discontinuation of its use.

Petroleum UST system: An underground storage tank system that contains petroleum or a mixture of petroleum with de minimis quantities of other regulated substances. Such systems include those containing motor fuels, jet fuels, distillate fuel oils, residual fuel oils, lubricants, petroleum solvents, and used oils.

Regulated substance:

1. Any substance defined in 101(14) of CERCLA (but not including any substance regulated as a hazardous waste under subtitle C); and
2. Petroleum, including crude oil or any fraction thereof that is liquid at standard conditions of temperature and pressure (60°F and 14.7 pounds per square inch absolute). The term “regulated substance” includes but is not limited to petroleum and petroleum-based substances comprised of a complex blend of hydrocarbons, such as motor fuels, jet fuels, distillate fuel oils, residual fuel oils, lubricants, petroleum solvents, and used oils.

Release detection: Determining whether a release of a regulated substance has occurred from the UST system into the environment or a leak has occurred into the interstitial space between the UST system and its secondary barrier or secondary containment around it.

Under-dispenser containment (UDC): Containment underneath a dispenser system designed to prevent leaks from the dispenser and piping within or above the UDC from reaching soil or groundwater.

State UST program approvals and regulation exemptions

• All states have a comprehensive set of UST leak prevention and release detection regulations and a program to implement those regulations.
• All states have cleanup and/or remediation programs addressing tank systems.
• Certain USTs are excluded from regulation and, therefore, do not need to meet federal requirements for USTs.

States and local governments may receive approval to oversee their own underground storage tank (UST) programs. State programs must be at least as stringent as federal Environmental Protection Agency’s (EPA’s) requirements.

All 50 states, plus the District of Columbia, have a comprehensive set of UST leak prevention and release detection regulations and a program to implement those regulations. Additionally, all states have cleanup and/or remediation programs addressing tank systems. Even for states without state program approval, EPA enters into grant/cooperative agreements with state programs, and the state program is designated as the primary implementing agency. While both federal and state regulations apply in states without state program approval, the state regulations must be as stringent as, and are often significantly more stringent than, EPA’s regulations.

Exemptions from UST regulations

The following underground storage tanks (USTs) are excluded from regulation and, therefore, do not need to meet federal requirements for USTs:

• Farm and residential tanks with a capacity of 1,100 gallons or less holding motor fuel used for noncommercial purposes;
• Tanks storing heating oil used on the premises where it is stored;
• Tanks on or above the floor of underground areas, such as basements or tunnels;
• Septic tanks and systems for collecting stormwater and wastewater;
• Flow-through process tanks;
• Tanks with a capacity of 110 gallons or less; and
• Emergency spill and overfill tanks.

Tank and piping installation

• Owners and operators need to make sure that installers carefully follow the correct installation procedures called for by industry codes and follow manufacturer’s instructions.
• All new and replaced tanks and piping must meet the secondary containment requirements, including interstitial monitoring.

Tanks installed after December 22, 1988, 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 underground storage tank (UST) installers be certified (in addition to being qualified) to conduct this type of work. Check with the implementing agency to be sure that owners and operators follow the appropriate regulations.

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.

Owners and operators 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 use one or more of the following methods of certification, testing, or inspection to demonstrate compliance with the installation requirements. They must also provide a certification of compliance on the UST notification form.

To demonstrate compliance with the installation requirements, certify that:

• 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.

All new and replaced tanks and piping must meet the secondary containment requirements, including interstitial monitoring. The Environmental Protection Agency (EPA) considers piping replaced when 50 percent or more of the piping is removed and other piping is installed. In addition, new dispenser systems must have under-dispenser containment.

Leak detection

• All regulated tanks and piping must have leak detection.

All regulated tanks and piping must have leak detection so that releases are discovered quickly before contamination spreads from the underground storage tank (UST) site. The owners and operators must provide the UST system with leak detection (also called release detection) that allows them to meet three basic requirements:

• They can detect a release from any portion of the tank or its piping that routinely contains petroleum;
• Their release detection is installed and calibrated in accordance with the manufacturer’s instructions; and
• Their release detection meets the performance requirements described in the federal regulations (280.43, 280.44, or Subpart K as applicable).

Note: Tanks 2,000 gallons and smaller may be able to use manual tank gauging to meet release detection requirements.

Inspections

• Owners and operators must conduct walkthrough inspections at their UST facility.
• The walkthrough inspection must meet one of three different options.

Walkthrough inspections

Owners and operators must conduct walkthrough inspections at their underground storage tank (UST) facility. The walkthrough inspection must meet one of the following:

Option 1: Every 30 days (with the exception of spill prevention equipment at UST systems receiving deliveries at intervals greater than every 30 days, which may be checked prior to each delivery), check spill prevention equipment and release detection equipment. Annually, check 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
  • Check double walled spill prevention equipment with interstitial monitoring 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
  • Check double walled containment sumps with interstitial monitoring for a leak in the interstitial area
• Check handheld release detection equipment (for example, tank gauge sticks or groundwater bailers) 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 the 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 Occupational Safety and Health Administration (OSHA) 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.

Leak detection methods

• For USTs installed or replaced after April 11, 2016, owners and operators must use secondary containment with interstitial monitoring.

Owners and operators of petroleum underground storage tanks (USTs) installed on or before April 11, 2016, must use at least one of the following release detection methods, or other methods approved by their implementing agency. For USTs installed or replaced after April 11, 2016, owners and operators must use secondary containment with interstitial monitoring.

• Secondary containment with interstitial monitoring. This involves placing a barrier between the UST and the environment. The barrier provides secondary containment and can be a vault, liner, or the outer wall of a double-walled structure. Interstitial monitoring methods range from a simple dip stick to automated vapor or liquid sensors permanently installed in the system. All USTs holding hazardous substances must use this method.
• Automatic tank gauging (ATG) systems. ATG systems use monitors permanently installed in the tank. These monitors are linked electronically to a nearby control device to provide information on product level and temperature. The gauging system can automatically calculate the changes in product volume that can indicate a leaking tank. ATG systems operate in one of two modes: inventory mode and leak detection mode. In the leak detection mode, ATG systems can be set manually or automatically to perform a leak test. Manual leak tests are in-tank static tests and automatic leak tests are continuous in-tank leak detection tests. This method does not work on piping.
• Continuous in-tank leak detection (CITLD). CITLD encompasses all statistically based methods where the system incrementally gathers measurements on an uninterrupted or nearly uninterrupted basis to determine a tank’s leak status. There are two major groups that fit into this category: 1.) continuous statistical release detection (also referred to as continuous ATG methods) and 2.) continual reconciliation. Both groups typically use sensors permanently installed in the tank to obtain inventory measurements. They are combined with a microprocessor in the ATG system or other control console that processes the data. Continual reconciliation methods are further distinguished by their connection to dispensing meters that allow for automatic recording and use of dispensing data in analyzing tanks’ leak status.
• Statistical inventory reconciliation (SIR). SIR uses sophisticated computer software to determine whether a tank system is leaking. The computer conducts a statistical analysis of inventory, delivery, and dispensing data collected over a period of time and provided by the operator to a vendor. SIR methods process data on a periodic basis involving a separate analysis that is performed either by an SIR vendor or SIR software.
• Groundwater monitoring. Groundwater monitoring devices sense the presence of liquid product floating on the groundwater. This method requires installation of monitoring wells at strategic locations in the ground near the tank and along the piping runs. To discover if leaked product has reached groundwater, these wells can be checked periodically by hand or continuously with permanently installed equipment. This method is effective only at sites where groundwater is within 20 feet of the surface.
• Vapor monitoring. Vapor monitors sense and measure either product vapor in the soil around the tank and piping (sometimes called passive monitoring) or a tracer compound (sometimes called active monitoring) to determine the presence of a leak. This method requires installation of carefully placed monitoring wells. Vapor monitoring can be performed periodically using manual devices or continuously using permanently installed equipment.
• Manual tank gauging. Manual tank gauging can be used only on tanks 2,000 gallons or smaller. This method requires taking the tank out of service for at least 36 hours each week to take measurements of the tank’s contents. Tanks 1,000 gallons or less can use this method alone. Tanks from 1,001 to 2,000 gallons can use this method only when it is combined with periodic tank tightness testing and only for 10 years after installing a new UST or upgrading a UST with corrosion protection. After 10 years, these USTs must use another release detection method.
• Tank tightness testing and inventory control. A combination of two methods, tank tightness testing requires periodic tests conducted by vendors who temporarily install special equipment that tests the soundness of the tank. Inventory control requires taking daily accurate measurements of the tank’s contents and performing monthly calculations to prove that the system is not leaking. Tank tightness testing and inventory control can be used only for 10 years after installing a new UST or upgrading an UST with corrosion protection. After 10 years, these USTs must use another leak detection method. Inventory control must be used in combination with tank tightness testing.

Leak detection methods for piping

• If the UST has suction piping that was installed on or before April 11, 2016, the release detection requirements will depend on which type of suction piping the owner and operator has.

Pressurized piping installed on or before April 11, 2016, must meet the following requirements:

• The piping must have devices that automatically shut off or restrict flow or trigger an alarm that indicates a leak.
• The owner and operator must either conduct an annual tightness test of the piping or use one of the following monthly methods:
  • Interstitial monitoring
  • Groundwater monitoring
  • Vapor monitoring
  • Continuous in-tank leak detection
  • Statistical inventory reconciliation
  • Other methods approved by the implementing agency

If the underground storage tank (UST) has suction piping that was installed on or before April 11, 2016, the release detection requirements will depend on which type of suction piping the owner and operator has. If the owner or operator can show that their suction piping has characteristics listed below, the piping will not need release detection.

• Below-grade piping operating at less than atmospheric pressure is sloped so that the piping’s contents will drain back into the storage tank if the suction is released.
• Only one check valve is included in each suction line and is located directly below the suction pump.

Suction piping that does not exactly match the characteristics noted above must have release detection, either monthly monitoring or tightness testing of the piping every three years.

Piping installed or replaced after April 11, 2016, must have secondary containment with interstitial monitoring, except suction piping that has the characteristics listed above. In addition, pressurized piping must have a device that automatically shuts off or restricts flow or triggers an alarm that indicates a leak.

Additional operation and maintenance activities for leak detection

• Certain actions are required as part of the walkthrough inspection for tank release detection and piping release detection every 30 days and annually.

For tank release detection: As part of the walkthrough inspection requirement, at least every 30 days:

• Check to make sure the release detection equipment is operating with no alarms or other unusual operating conditions present; and
• Ensure records of release detection testing are reviewed and current.

Annually:

• Check hand-held release detection equipment such as tank gauge sticks and groundwater bailers for operability and serviceability; and
• Test operability of mechanical and electronic release detection equipment such as automatic tank gauges, probes, and sensors, and make sure they are working properly.

For piping release detection: As part of the walkthrough inspection requirement and at least every 30 days:

• Check to make sure the devices being used are automatically shut off or restrict flow of product or triggers an alarm to indicate a leak are operating with no alarms or other unusual operating conditions present; and
• Ensure records of testing these devices are reviewed and current.

Annually:

• Visually check containment sumps with interstitial monitoring for damage, leaks to the containment area, or releases to the environment;
• Check double-walled sumps with interstitial monitoring for a leak in the interstitial area.

Owners and operators must also annually test operability and determine devices they are using to automatically shut off or restrict flow or trigger an alarm. To indicate a leak in the piping, meet the three gallons per hour at 10 pounds per square inch line pressure within one hour performance standard, by simulating a leak. Operability of mechanical and electronic components such as suction pumps of suction systems must also be tested annually to ensure they are operating as required.

Leak detection reporting and recordkeeping

• If operation of the release detection method indicates a possible release, owners and operators need to report the potential release to the appropriate regulatory authority.

If operation of the release detection method indicates a possible release, underground storage tank (UST) owners and operators need to report the potential release to the appropriate regulatory authority. UST owners and operators must also keep records on release detection performance and upkeep. These include:

• The previous year’s monitoring results,
• The most recent tightness test results,
• Performance claims by the release detection device’s manufacturer, and
• Records of recent maintenance and repair.

Owners and operators must also keep the following records:

• Operation and maintenance walkthrough inspections that are required for periods of at least every 30 days and annually for one year;
• Release detection equipment that is tested annually to ensure proper operation for three years; and
• If the owners and operators store regulated substances containing greater than 10 percent ethanol or greater than 20 percent biodiesel, or any other regulated substance identified by the implementing agency, they must keep records demonstrating compatibility of the release detection components in contact with the regulated substances for as long as the UST system stores the regulated substance.

Leak detection for previously deferred UST systems

• UST regulation removes the deferral for UST systems that store fuel solely for use by emergency power generators, field-constructed tanks, and airport hydrant fueling systems.

The 2015 underground storage tank (UST) regulation removes the deferral for UST systems that store fuel solely for use by:

• Emergency power generators (emergency generator tanks);
• Field-constructed tanks; and
• Airport hydrant fueling systems.

Emergency generator tanks

These UST systems must meet release detection requirements as follows:

• Systems installed on or before October 13, 2015, have three years to use any of the applicable release detection methods.
• Systems installed between October 13, 2015, and April 11, 2016, must use any of the applicable release detection methods listed above at installation.
• Systems installed or replaced after April 11, 2016, must meet secondary containment requirements with interstitial monitoring.

Field-constructed tanks (FCTs) and airport hydrant systems (AHSs)

Owners and operators must meet release detection requirements. Field-constructed tanks (FCTs) and airport hydrant systems (AHSs) installed on or before October 13, 2015, must have release detection by October 13, 2018. FCTs and AHSs installed after October 13, 2015, must meet all release detection requirements at installation. Tanks and some piping installed after April 11, 2016, must be secondarily contained and use interstitial monitoring. Owners and operators may use single walled piping when installing or replacing piping associated with UST systems with FCTs greater than 50,000 gallons and piping associated with AHSs.

Spill protection

• Spill protection is containment around the fill pipe of a (UST that catches small drips or spills that occur when the delivery hose is disconnected from the fill pipe.
• If a UST never receives more than 25 gallons at a time, the UST does not have to meet the spill protection requirements.

Spill protection is containment around the fill pipe of an underground storage tank (UST) that catches small drips or spills that occur when the delivery hose is disconnected from the fill pipe. This containment is typically called a spill bucket. It may also be referred to as a catchment basin, or spill containment manhole. Basically, a spill bucket is a basin sealed around the fill pipe. To protect against spills, the spill bucket should be large enough to contain what may spill when the delivery hose is uncoupled from the fill pipe. A typical delivery hose can hold about 14 gallons of fuel. Spill buckets range in size from those capable of holding only a few gallons to those that are much larger — the larger the spill bucket, the more spill protection it can provide. Spill buckets must be either double walled (with periodic monitoring of the integrity of both walls of the spill bucket) or tested periodically for proper operation according to the new spill prevention equipment testing requirements that went into effect in October 2018.

Owners and operators need a way to remove liquid from spill buckets. Manufacturers may equip spill buckets with either a pump or drain to remove liquid, or can purchase a spark-free hand pump. Try to keep the spill bucket clean and empty — some spill buckets can collect enough water and sediment, along with spilled product, to make draining this mixture into the tank unwise. If this happens, the owners and operators may pump out the spill bucket and dispose of the liquid properly. If the liquid contains fuel or chemicals, it could be considered a hazardous waste. Contact the implementing agency responsible for hazardous waste for information on testing and handling requirements.

Note: If a UST never receives more than 25 gallons at a time, the UST does not have to meet the spill protection requirements. Many small used oil tanks fall into this category.

Overfill and corrosion protection

• There are three types of overfill protection devices automatic shutoff devices, overfill alarms, and flow restrictors.
• All metal UST system components that are in contact with the ground and routinely contain product must be protected from corrosion.

Overfill protection are devices that either shut off product flow, restrict product flow, or alert the delivery operator with an alarm when the tank is close to being full. These devices are installed inside the tank and activate if the product in the underground storage tank (UST) reaches a certain level in the tank. Typically, a company’s UST must have overfill protection, and overfill prevention equipment must be inspected periodically for proper operation. The three types of overfill protection devices are:

• Automatic shutoff devices,
• Overfill alarms, and
• Flow restrictors (also called ball float valves).

Note: If a UST never receives more than 25 gallons at a time, the UST does not have to meet the overfill protection requirements. Many small used oil tanks fall into this category.

Corrosion protection

Unprotected underground metal components of an underground storage tank (UST) system can corrode and release product through corrosion holes. Corrosion can begin as pitting on the metal surface, and as the pitting becomes deeper, holes may develop. Even a small corrosion hole can result in significant releases over time.

In addition to tanks and piping, metal components can include flexible connectors, swing joints, and turbines. All metal UST system components that are in contact with the ground and routinely contain product must be protected from corrosion. The two common methods used for protecting metal components from corrosion are cathodic protection and isolating the metal component from the corrosive environment.

All USTs installed after December 22, 1988, must meet one of the following performance standards for corrosion protection:

• Tank and piping completely made of noncorrodible material, such as fiberglass-reinforced plastic.
• Tank and piping made of steel having a corrosion-resistant coating and having cathodic protection.
• Tank made of steel clad or jacketed with a thick layer of noncorrodible material (this option does not apply to piping).

Tanks and piping may be installed without additional corrosion protection measures provided that a corrosion expert has determined that the site is not corrosive enough to cause it to have a release due to corrosion during its operating life and owners/operators maintain records that demonstrate compliance with this requirement.

UST systems installed before December 22, 1988, must be protected from corrosion. These USTs must meet one of the corrosion protection standards listed above or meet one of the upgrade options described below (or be properly closed):

• Interior lining,
• Cathodic protection, and
• Internal lining combined with cathodic protection.

Important: Prior to adding cathodic protection, the integrity of the tank must have been ensured using one of the following methods:

• The tank is internally inspected and assessed to ensure that the tank is structurally sound and free of corrosion or holes.
• The tank has been installed for less than 10 years and uses monthly monitoring for releases.
• The tank has been installed for less than 10 years and is assessed for corrosion holes by conducting two tightness tests — the first occurs prior to adding cathodic protection and the second occurs three to six months following the first operation of cathodic protection.
• An alternative integrity assessment where the tank is assessed for corrosion holes by a method that is determined by the implementing agency to prevent releases in a manner that is no less protective of human health and the environment than those listed immediately above.

Upgrading bare metal piping is accomplished by adding cathodic protection.

In addition, metal pipe sections and fittings that have released product as a result of corrosion or other damage must be replaced. Piping entirely made of (or enclosed in) noncorrodible material does not need cathodic protection.

Inspection frequency, criteria, and records

• All cathodic protection systems must be tested within six months of installation and at least every three years thereafter.

All underground storage tank (UST) systems equipped with cathodic protection systems must be inspected for proper operation by a qualified cathodic protection tester in accordance with the following requirements:

1. Frequency: All cathodic protection systems must be tested within six months of installation and at least every three years thereafter or according to another reasonable time frame established by the implementing agency; and
2. Inspection criteria: The criteria that are used to determine that cathodic protection is adequate must be in accordance with a code of practice developed by a nationally recognized association.

Records

For UST systems using cathodic protection, records of the operation of the cathodic protection must be maintained (in accordance with 280.34) to demonstrate compliance with the performance standards. These records must provide the following:

• The results of the last three inspections required in paragraph (c) of 280.31; and
• The results of testing from the last two inspections required in paragraph (b) of 280.31.