Underground Storage Tank System Exposures

An underground storage tank system (UST) is a tank and any underground piping connected to the tank that has at least 10 percent of its combined volume underground. Federal UST regulations exist specifically for underground tanks and piping that contain petroleum or certain other hazardous substances.

The Environmental Protection Agency (EPA) and other government agencies are concerned about USTs because, until the mid-1980s, most were made of bare steel, which often corrodes over time and allows contents to leak into the environment. Faulty installation or inadequate operation and maintenance procedures also can cause USTs to leach their contents into the surroundings. The greatest potential hazard from a leaking UST is that the petroleum or other hazardous substance can seep into the soil and contaminate groundwater, which is the source of drinking water for nearly half of all Americans. In addition, a leaking UST can present other serious health and environmental risks, including the potential for fire and explosion.

This post will summarize the federal regulations and requirements for underground storage tanks so you can stay in compliance and ensure safe operation and maintenance of your storage tank.

Overview of the Federal UST Program

• Do all tanks have to meet federal EPA regulations?

The following USTs do not need to meet federal requirements for USTs:

• Farm and residential tanks with a capacity of1,100 gallons or less that are 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 storm water and wastewater
• Flow-through process tanks
• Tanks with a capacity of 110 gallons or less
• Emergency spill and overfill tanks

Keep in mind, however, that some state or local regulatory authorities may include these tank types in their laws.

• What are the federal requirements for USTs?
• Technical Requirements for USTs: The EPA’s technical regulations for USTs are designed to reduce the chance of releases, detect leaks and spills when they do occur and secure a prompt cleanup. UST owners and operators are responsible for reporting and cleaning up any releases.
• Financial Responsibility Regulations for USTs: The financial responsibility regulations are designed to 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 and compensating third parties.

Leaking Underground Storage Tank (LUST) Trust Fund

• What is the LUST Trust Fund?

The LUST Trust Fund, created by Congress in 1986, has two purposes: (1) It provides money for overseeing and enforcing corrective action taken by the owner or operator of the leaking UST and (2) It provides money for cleanups at UST sites where the owner or operator is unknown, unwilling or unable to respond, or for situations that require emergency action. States may receive money from the fund by entering into a cooperative agreement with the federal government to spend the funds for their intended purpose.

• How much do cleanups cost?

Cleanup costs depend on a variety of factors, including the extent of contamination and state cleanup standards; in general, the average cleanup is estimated to cost $125,000. If only a small amount of soil needs to be removed or treated, cleanup can be as low as $10,000. However, costs to clean more extensive soil contamination may greatly exceed the average figure. Corrective action for leaks that affect groundwater typically cost between $100,000 and $1 million depending on the extent of contamination. For instance, the presence of methyl tertiary-butyl ether (MTBE) can lead to a substantial increase in cleanup and drinking water treatment costs.

Detecting Releases

• Why is release detection crucial?

All regulated tanks and piping must have release detection so that leaks are discovered quickly before contamination spreads from the UST site. You must provide your UST system with release detection (often also called leak detection) that meets three basic requirements:

1. You can detect a leak from any portion of the tank or its piping that routinely contains petroleum.
2. Your leak detection is installed, calibrated, operated and maintained in accordance with the manufacturer’s instructions.
3. Your leak detection meets the performance requirements described in the federal regulations.

• What leak detection methods can you use to detect leaks from tanks?

Owners and operators of petroleum USTs must use at least one of the leak detection methods below or another method that has been approved by their state agency.

1. Secondary Containment and 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 that were installed after December 22, 1988 must use this method.

2. Automatic Tank Gauging (ATG) Systems:

ATGs 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. This method does not work on piping.

3. Vapor Monitoring:

Vapor monitors sense and measure product vapor in the soil around the tank and piping 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 by continuously using permanently installed equipment.

4. 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.

5. 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.

6. Manual Tank Gauging:

Manual tank gauging can be used only on tanks 2,000 gallons or smaller and does not work on tanks larger than 2,000 gallons or on piping. 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 holding 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 an UST with corrosion protection.

7. Tank Tightness Testing and Inventory Control:

This method can be used temporarily at petroleum UST sites, and is a combination of two methods. Tank tightness testing requires periodic tests conducted by vendors who temporarily install special equipment that test the soundness of the tank. Tank tightness testing must be used in combination with inventory control, which 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.

• What leak detection methods can you use to detect leaks from piping?

Pressurized piping must meet the following requirements:

• The piping must have devices that automatically shut off or restrict flow, or they must have an alarm that indicates a leak.
• You must either conduct an annual tightness test of the piping or use one of the following monthly methods:
  • Interstitial monitoring
  • Vapor monitoring
  • Groundwater monitoring
  • Statistical inventory reconciliation
  • Other methods approved by the implementing agency

If your UST has suction piping, your requirements will depend on which type of suction piping you have.

• If your suction piping has characteristics listed below, your piping may not need leak detection:
  • Below-grade piping operating at less than atmospheric pressure that 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 leak detection systems in place, which may be either monthly monitoring (using one of the monthly methods noted above for use on pressurized piping) or tightness testing of the piping every three years.
• Why might you fail to be in compliance even if you have the required leak detection equipment or method?

It takes more than equipment to be in compliance and to have a safe facility. You must operate and maintain this equipment properly over time or you will not benefit from having the equipment or using an approved leak detection method. Most importantly, you must be sure that you successfully use the method at least once a month to determine if the UST system has released any of its contents.

Failure to operate and maintain equipment and methods can lead to new releases. For example, a poorly functioning ATG system will provide inaccurate data that will be useless in detecting leaks. A manual vapor or groundwater monitoring device that does not work properly means you have no reliable leak detection system. Inaccurate data from poorly operated and maintained measuring devices can make SIR methods unable to detect leaks in a timely manner. If your leak detection fails, you may incur fines or penalties for noncompliance in addition to expensive cleanup costs at your UST site.

• Are reporting and recordkeeping necessary?

If operation of the leak detection method indicates a possible leak, UST owners and operators need to report the potential release to the regulatory authority. UST owners and operators must keep records on leak detection performance and upkeep. These include the previous year’s monitoring results, the most recent tightness test results, performance claims by the leak detection device’s manufacturer and records of recent maintenance and repair.

Cleaning Up Underground Storage Tank System Releases

• Why do UST releases need to be cleaned up?

The EPA’s federal UST regulations require that contaminated UST sites must be cleaned up to restore and protect groundwater resources and create a safe environment for those who live or work around these sites. Petroleum releases can contain contaminants like MTBE and other contaminants of concern that can make water unsafe or unpleasant to drink. Releases can also result in fire and explosion hazards as well as produce long-term health effects.

• What cleanup methods are available?

Several methods have been successfully used to clean up leak sites. Often, the characteristics of a site (type of soil, proximity to groundwater, etc.) make it a better candidate for some cleanup methods than others. A contaminated site will need a site assessment, which will help professionals choose the best cleanup method. Professional cleanup contractors base their decisions on site-specific investigations and local environmental agency approval. In some cases, state or federal regulators take the lead at a contaminated UST site and will make all the cleanup decisions.

• Are there ways to control the cost of these potentially expensive cleanups?

The EPA is committed to helping state and local agencies make cleanups faster, more effective and less expensive. The EPA is working with states to encourage the use of expedited site assessment and alternative cleanup technologies and is also encouraging state and local agencies to incorporate risk-based decision making and pay-for-performance agreements into their corrective action programs. The EPA also has grant money that encourages both environmentally effective cleanups and the re-development of these areas.

For more information on underground storage tanks, visit the EPA’s website at http://www.epa.gov. For more information on completing your risk management plan, contact INSURICA.

Source: Environmental Protection Agency (EPA)