Underground storage tanks (USTs) are used at numerous commercial and residential properties to store fuels and oils for refueling and maintaining vehicles and equipment, providing emergency back-up power, and for on-site heating systems. USTs may be used to store hazardous chemicals or other products, but petroleum storage tanks are by far the most common and are the focus of this article. Due to the nature of the stored substances, the volumes of liquid typically requiring storage, as well as the limited available space on most properties, it often becomes necessary to install storage tanks below grade. A UST is defined by Federal regulations as a tank that stores a regulated substance which has 10% or more of the system's volume—including the tank and associated piping—below the ground surface. Typical USTs vary in size from 550 gallons up to 50,000 gallons in capacity and can be found almost anywhere and everywhere including gas stations, automobile dealerships, commercial office buildings, industrial plants, colleges/universities, hospitals, and residences, just to name a few examples. Standard USTs are horizontal cylinders constructed of fiberglass, steel, and/or a composite material (e.g. fiberglass reinforced plastic (FRP), carbon fiber wrapped around a steel liner). USTs are often considered a necessary evil based on the environmental liabilities associated with their presence on a property.

The EPA initiated UST regulation back in the 1980's (40 CFR Parts 280, 281 & 282), because many USTs had leaked into surrounding soils causing environmental pollution, health and safety issues, and impacts to groundwater (the source of domestic water for over 40% of the U.S. population). In addition to Federal regulation, many states have instituted their own UST regulation programs that are more stringent than EPA requirements. For example, EPA regulations do not apply to non-commercial farm or residential tanks smaller than 1,100 gallons or those used for storage of heating oil for onsite consumption; however, many state programs include requirements for those tanks. Based on applicable regulations and upgrade requirements for older tanks, more than 1.7 million USTs have been removed since 1984. The EPA currently estimates there are approximately 581,000 active regulated USTs in the United States. Far more exist as abandoned or non-registered USTs which are often uncovered during property redevelopment projects. Many of these unknown USTs lead to costly remedial activities due to major deterioration and lack of maintenance over time.

Compliance and maintenance of USTs are critical in order for property owners and tank owners/operators to avoid costly fines and potential expensive cleanup costs and to protect from other environmental liability. The following are some basic steps to meeting and/or exceeding regulations:

Is the UST registration accurate and complete?

Federal and state regulations require that regulated USTs be registered with the appropriate state agency. Apex recommends a routine compliance audit of UST systems, part of which should include confirmation of accurate, complete registration paperwork. This is especially important in jurisdictions where there are different requirements for different types of tanks.

Is the UST system properly equipped with spill protection?

As of 1998—all USTs are required to comply with federal regulations and contain spill protection, which consists of a catchment basin (spill bucket) on the fill port. Spill buckets vary in size based on individual state requirements and are designed to capture the remaining fuel within the delivery hose after the hose is disconnected, preventing a surface release. Apex recommends that spill buckets be inspected for cracks and tears and be hydrostatically tested periodically to confirm the integrity of the container, ensuring it can hold liquid at a constant level.

Is the UST system properly equipped with overfill protection?

As of 1998—all USTs are required to comply with federal regulations and contain overfill protection, which consists of an overfill protection device (e.g. drop tube, overfill alarm, ball float valve). These devices are designed to prevent overfilling a tank during deliveries and help indicate to the fuel deliverer/operator when the UST reaches a certain level of capacity (typically set at 90% or 95%). Apex recommends that a trained technician inspect overfill devices periodically for proper functionality (e.g. flapper valve associated with drop tube is working, overfill alarm is set to proper level with working audible and visual alarms, and/or ball float is present.

Is the UST system equipped with a proper functioning tank monitoring system?

A tank monitoring system is the "heartbeat" of a tank system and is often an integral component for complying with the release detection required for all regulated USTs. These systems use probes and sensors installed within various components of the UST system to detect a leak from any portion of the tank or associated piping, record a continuous status of liquid levels (detect a loss/gain) within the tank, monitor the secondary containment areas for liquids (leaking fuel or water intrusion), keep monthly reconciliation records, and some also monitor for fuel vapors. Like other technology, tank monitoring systems continue to become more sophisticated. Newer models are more user-friendly and are often designed to monitor UST systems remotely. Apex recommends that tank monitoring systems be calibrated (required by state and federal regulations) on an annual basis to correct for variations that occur over time. At the time of the calibration, the technician will inspect the associated probes and sensors to confirm functionality and confirm that no active alarms are present on the console.

Is the UST system and associated piping equipped with corrosion protection?

All UST systems must be protected from corrosion due to contact with soil and water. Use of non-conductive materials, such as fiberglass, is an effective strategy, but any UST and/or piping component made of steel or copper must have a mechanism of preventing corrosion or pitting. Corrosion and pitting can eventually lead to a leak within the system. Steel USTs and piping are typically installed with sacrificial anodes or an impressed current system, which helps protect against the corrosion from small electrical currents induced between the metal tank system and the surrounding soils. Certain soil types, such as clays, tend to be more corrosive due to their increased conductivity. Apex recommends that cathodic protection systems be tested every 3 years or as required by local regulations with records kept on-site for proper documentation.

Is proper liability coverage in place?

Financial responsibility is a requirement of federal UST regulations, which require that an owner or operator demonstrate the financial capacity to cover costs associated with a cleanup and to compensate third parties in the event of a release from the UST system. Most general liability insurance policies do not cover a release from an UST, and therefore, supplemental UST insurance policies are often purchased to cover UST releases and demonstrate compliance with financial responsibility requirements. Apex recommends reviewing and confirming that adequate liability coverage exists as part of a routine compliance audit.

Are the necessary testing and inspections being performed?

Based on the state and type of tank, USTs are required to undergo several types of inspections and/or periodic tests. Examples include: hydrostatic testing of spill buckets and containment sumps to confirm no leaks occur and the units are tight, precision testing to confirm the UST and associated piping are integrally tight, periodic 3rd party inspections of the entire fueling system (e.g. required every 3 yrs. in Maryland), and line and leak detectors tested for leaks and functionality. Apex recommends a review of the applicable state and federal inspection and testing requirements for each type of UST on a property.

Is general housekeeping performed at the UST site?

Maintaining a clean and properly functioning UST system is very important for regulatory compliance. Some general elements of a well-maintained system include: keeping the kiosk associated with the system clean, storing pertinent Safety Data Sheets and prior testing records on site, maintaining the spill buckets and containment sumps free of water and debris, maintaining the manholes and covers intact and properly painted in accordance with the correct A.P.I. color code, maintaining a tank gauge stick along with a tank chart, proper maintenance and storage of hoses associated with dispensers, maintaining fire extinguishers on-site, and maintaining a standardized check list as a helpful way to perform monthly evaluations of the fueling facility.

These are just a few of the key considerations associated with owning and operating UST systems. As noted, each state has different regulations and requirements, including requirements for UST workers to be certified to perform work on a system. Apex's staff are certified in many states to install, remove, and service UST systems. For more information or specific questions about a UST system, please contact Apex at 800-733-APEX (2739).

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