Managing Underground Storage Tanks in the United States

Claudia J. Gutierrez, Research Scientist, US Environmental Protection Agency, Region II

Jack Caravanos, DrPH, Assistant Professor, Hunter College CUNY

I. INTRODUCTION

Over one million underground storage tank systems (USTs) in the United States contain petroleum or hazardous substances regulated by the United States Environmental Protection Agency (EPA). Many of these underground storage tanks have leaked. This paper seeks to briefly describe the obligations tank owners have in managing underground petroleum storage tanks.

Releases from USTs arising from spills, overfills or leaking tanks and piping can cause fires or explosions that threaten human safety. Releases can also pose a significant health threat by contaminating the groundwater that many of us depend on for the water we drink. Properly managed, USTs will not threaten our health and the environment. This is a problem worldwide since releases from underground storage tanks can threaten human health and safety. UST releases can also contaminate soil and drinking water supplies. More than 287,000 UST releases have been confirmed in the US, EPA estimates half that about of these releases reached groundwater.

Federal legislation, directed EPA to develop the underground storage tank regulations which requires owners and operators to:

  • prevent releases from USTs,
  • detect releases from USTs, and
  • correct the problems created by releases from USTs.

US EPA defines an underground storage tank as a tank and any underground piping connected to the tank that has at least 10 percent of its combined volume underground. The federal regulations apply only to USTs storing either petroleum or certain hazardous substances and not food or other non-hazardous materials.

II. FEDERAL REGULATIONS

Release Detection Monitoring Methods

The US Environmental Protection Agency has research release detection monitoring methods and has mandated owners adopt a program to detect leaks. The technologies are briefly described below.

  • Interstial Monitoring: This method detects leaks in the space between the UST and a second barrier. The regulations describe general performance requirements for interstial monitoring with double-walled USTs, USTs fitted with internal liners and USTs using interception barriers.
  • Automatic Tank Gauging Systems: This method uses automated processes to monitor product level and inventory control.
  • Groundwater Monitoring: This method monitors the groundwater table near an UST for the presence of released free product on the water table. Monitoring wells near the UST are checked frequently to see if petroleum can be detected. However, this method cannot be used if the water table is more than 20 feet below the surface of the ground.
  • Soil Vapor Monitoring: This method samples vapors in the soil gas surrounding the UST. Leaked petroleum produces vapors that can be detected in the soil gas. However, this method requires using porous soils in the backfill and locating monitoring devices in these porous soils near the UST system.
  • Statistical Inventory Reconciliation: This method uses sophisticated computer software to conduct a statistical analysis of inventory, delivery and dispensing data, which you must supply regularly.

Instead of using one of the monthly monitoring methods noted above you can combine inventory control and tank tightness testing, but only for 10 years after you install a new UST. Inventory control involves taking daily measurements of tank contents and recording deliveries and amount pumped. Tank Tightness Testing requires taking the UST out of service while changes in level or volume are measured over time.

Spill Protection

USTs must have catchment basins to contain spills. Catchment basins are also called spill containment manholes or spill buckets. Basically, a catchment basin is a bucket sealed around the fill pipe. To protect against spills, the basin should be large enough to contain what may spill when the delivery hose is uncoupled from the fill pipe.

Overfill Protection

USTs must have overfill protection when they are installed. The three main types of overfill protection devices are:

  1. Automatic shutoff devices: An automatic shutoff device installed in an UST’s fill pipe can slow down and then stop the delivery when the product has reached a certain level in the tank.
  1. Overfill alarms: Overfill alarms use probes installed in the tank to activate alarm when the tank is either 90 percent full or within 1 minute of being overfilled. The alarm provides the driver to close the truck’s shutoff valve before an overfill happens.
  1. Ball float valves: Ball float valves are placed at the bottom of the vent line several inches below the top of the UST. The ball floats on the product rises with product level during delivery until it restricts vapor flowing out the vent line before the tank is full. If all tank fittings are tight, the ball float valve can create enough back pressure to restrict product flow into the tank which notifies the driver to close the truck’s shutoff valve.

Corrosion Protection

Tank and piping completely made of noncorrodible material such as fiberglass. Also, provided if tank and piping are completely isolated from contact with the surrounding soil by being enclosed in or jacketed in noncorrodible material

Tank and piping made of steel having a corrosion-resistant coating and having cathodic protection. A corrosion-resistant coating electrically isolates the coated metal from the surrounding environment to help protect against corrosion. Tank made of steel clad with a thick layer of noncorrodible material.

III. USING A DATABASE TO BETTER MANAGE THE UST WORLD

US EPA has delegated the registration and data management of New York States underground storage tanks to the Department of Environmental Conservation. This database keeps track of all USTs in New York State and the spills occurring from releases of product in New York State and is used by federal EPA offices in evaluating and ensuring compliance with federal regulations. However, USTs in New York State are only required to register tanks whose capacity is over 1,100 gallons.

Petroleum Bulk Storage Database

This database requires owners and operators to register their tanks with New York State. The facility must have a total capacity of 1,100 gallons or more to be regulated. The following must be submitted in order for the registration to be approved:

  • Name, location and phone number of the facility;
  • Name of operator of the facility;
  • Name and address of owner of the facility;
  • Type of petroleum facility such as: storage terminal/petroleum distributor, retail gasoline sales, other retail sales, manufacturing, utility, trucking /transportation, apartment building, school, farm, airline, private residence, etc.
  • Tank number
  • Tank location
  • Status
  • Installation date
  • Capacity
  • Product stored
  • Tank Type, Tank Internal and External Protection
  • Piping type, internal and external protection
  • Secondary containment
  • Release detection
  • Spill/Overfill protection
  • Type of dispenser
  • Certification that all documentation submitted is true and correct. False statements are punishable by Law.

Spill Database

Any person with knowledge of a spill, leak or discharge of petroleum must report the incident to the New York State within 2 hours of discovery. Also, the results of any inventory record, test or inspection that shows a facility is leaking must be reported. This database has all the information of the spills reported to the New York State. The following information must be submitted when calling to report a spill approved:

  • Name of facility
  • Name of caller, address and phone number
  • Date of Spill
  • Time of Spill
  • Material Spilled
  • Amount Spilled
  • Amount Recovered
  • Spill caused
  • Resource affected
  • Spill Source
  • Remarks
  • Registration information

IV. CONCLUSION

Releases are bound to happen if you own and or operate a UST system, but they can be minimized if you do proper management of the tanks. Warning signals indicate that your UST may be leaking and creating problems for the environment and your business. You can minimize these problems by paying careful attention to early warning signals and reacting to them quickly before major problems develop.

Proper management is the key to avoiding any releases into the environment. However, if a release is suspected, you must respond quickly to any evidence of released petroleum that appears at your facility. Report it immediately to the appropriate agencies this way public health and the environment are not jeopardized.

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