Old heating oil tank being removed (C) Daniel FriedmanA Primer on Petroleum Bulk Storage Tanks and Petroleum Contamination of Property

  • BULK STORAGE OF PETROLEUM PRODUCTS - CONTENTS: An overview of oil storage tank regulations governing petroleum bulk storageOil Storage Tank Leak Problems, Regulations & Cleanup Costs; Oil Storage Tank Registration Requirements; Oil Storage Tank Testing Recommendations; Conditions and overt indications of petroleum contamination - has there been an oil tank leak?; What are the indications of site contamination from leaky oil tanks? Oil Storage Tank Leak Reporting Requirements - a Summary of Oil Tank Leak Issues
  • POST a QUESTION or READ FAQs about bulk oil storage tank leaks, regulations, issues, & oil leak or spill cleanup
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

This article presents basic information on the regulations governing petroleum bulk storage and then identifies conditions and overt indications of petroleum contamination. The article provides information on indications of site contamination.

Green links show where you are. © Copyright 2017, All Rights Reserved.

Oil Storage Tank Leak Problems, Regulations & Cleanup Costs

-- Paul H. Ciminello, Environmental Test Consultant, Ecosystems Strategies, Poughkeepsie, NY.

The past fifteen years have witnessed a meteoric increase in awareness of the potential problems associated with improper handling and storage of petroleum. Literally hundreds of thousands of incidents of identified soil, ground water and/or surface water contamination have been traced to the storage of petroleum at the millions of tanks across the country. It is estimated(1) that 15% to 30% of all underground storage tanks have some leakage.

Cleanup costs range from $5000., to 1 million or more, averaging $40,000. In the Northeast where tanks are older as many as 50% of tanks presently installed may be a problem today. In some New York areas, 54% of the spills reported to the state spill hot line sere from residential oil tanks!

This awareness has resulted in a need for all professionals who are involved in property inspection and management to understand the regulations governing petroleum storage and to be sensitive to overt indications of tank failure or site contamination. All categories of property are affected, including residential.

The primary focus of petroleum tank regulations is to provide procedures for proper petroleum storage. Towards this end, most regulations provide specifications on tank registration, tank precision testing, reporting leaks and tank management (maintenance and monitoring). Each element is briefly discussed below.

Petroleum bulk storage is governed on at least two levels-federal and state regulations-in most states. Federal regulations address underground storage of a wide range of chemicals, including petroleum; in New York State, regulations address the storage of petroleum in both aboveground and below ground tanks separately from the storage of chemicals. The owner of a facility is obligated to comply with regulations from all levels of government (even when these regulations vary).

Different regulations, even when addressing the same issue, will approach a problem differently and therefore are likely to be at times inconsistent and at other times contradictory. Petroleum storage regulations are no exception. Significant exemptions or variations in the regulations are identified below as each topic is discussed.

Oil Storage Tank Registration Requirements

Tank registration provides a regulatory agency with information on the size and location of tanks at a given facility. The registration of tanks by a property owner is at this time merely a notification requirement. Inherent in registration is a tacit agreement between the property owner and the state that the tanks will be maintained in accordance with applicable regulations. However, registration itself is merely for record-keeping. Registration is not a license to store petroleum. The state is not conveying to the property owner permission or the ability to store petroleum.

The determining factors in whether or not a petroleum storage tank must be registered with a regulatory agency is the contents of the tanks and the cumulative (not individual) size of the permanent tanks on a particular property (facility). In New York State, all tanks storing petroleum products with the exception of waste oil tanks where the waste oil is not re-used on the site must be registered. Federal regulations further exempt home heating oil tanks from registration regardless of volume.

Tanks with a cumulative total volume greater than 1,100 gallons must be registered in New York State. For example, a facility containing five 275 gallon tanks is subject to tank registration because, although each individual tank is less than 1,100 gallons, the total site volume exceeds 1,100 gallons.

Similarly, a site with one underground 550 gallon tank and three aboveground 275 gallon tanks is also subject to registration requirements (the location of the tank, aboveground or below ground, has no bearing on the need to register). Finally, a site with two 2,000 gallon tanks and a 275 gallon tank must register all three tanks that are being used at this facility.

Several exemptions and variation to tank registration exist. Tanks located on farm property and used for agricultural purposes do not require registration. In addition, waste oil tanks where the waste oil is re-used on the site (e.g., in a waste oil furnace) do not require registration. In other states and in federal regulations, waste oil may be determined to be a hazardous waste and therefore storage of this product may be subject to other, more stringent, regulations.

Oil Storage Tank Testing Recommendations

Tank testing to determine if the tank is leaking can be performed on any above or below ground tanks of any size, but is required only for underground tanks greater than 1,100 gallons in size. Tanks that are aboveground are exempt from testing requirements.

Tank testing is required for most underground tanks with an individual size greater than 1,100 gallons. The need to have a tank tested is based on the age and construction of the tank. Generally, all tanks which have been in the ground at least ten years and have not been previously tested will require a precision test.

Types and Accuracy of Tests for Oil Storage Tank Leaks

Volumetric and Pressure Tests for Oil Tank Leaks

Precision tests fall into two general categories: volumetric and pressure (other methods exist but these two techniques are the most common). Both methods measure the level of the product in the tank over a predetermined period of time (usually no shorter than four hours) and measure changes in the product level.

Because product levels will change as temperature varies, product level variations must be adjusted for even slight changes in the temperature of the material in the tank. Product temperature is more important as the size of the tank and the volume of the product contained within that tank increases; that is, temperature is a negligible factor for test on small, household tanks (275 or even 550 gallon tanks).

The results of a test will be provided as an estimated rate of change in tank volume over time, generally shown as gallons per hour. Both federal and state regulations state that product fluctuations less than 0.05 gallons per hour will not be considered a "leak". Any change in product level greater than 0.05 gallons per hour is considered evidence that product is leaking from the tank.

Oil Storage Tank Leak Reporting Requirements

A regulatory agency must be contacted upon completion of any tank test or when a change in the status of a tank is anticipated and completed. "Change in status" refers to temporarily or permanently closing a tank or installing a new tank.

However, a facility owner (and the enforcing agency) will be most concerned when reporting requirements are invoked as a result of a leak of petroleum.

Evidence of a leak is considered by federal and state regulations and subsequent guidance documents prepared by enforcement agencies to be one or more of the following:

A report must be submitted to the involved agency within two (2) hours of knowledge of a leak. This requirement had its origins in the navigation laws from whence petroleum bulk storage laws and regulations draw much of their substance. The purpose was to initiate remedial response as quickly as possible, particularly in the event of a release from an oil tanker on the water.

The need for immediate notification and remedial response is still relevant after the failure of a tank test; it has been argued that immediate notification is less relevant in instances where petroleum contaminated soil is encountered.

Both federal and state regulations permit the enforcing agency to compel the owner of the facility to effectively remediate the site including, if necessary, retaining a remediation firm to perform the work and levying fines and placing a lien on the property.

Oil Tank Management - federal and state regulations

The tank management sections of federal and state regulations represent possibly the most important and least appreciated sections of the rules on petroleum storage. These sections provide guidance on the ways in which petroleum should be stored so as to prevent future leaks or minimize the damage caused by an unintentional release.

Among the specific requirements in the tank management sections of the regulations are the following

Observations of Petroleum Oil Leak Contamination

Petroleum contamination can and does occur on all categories of property, from single family homes to major industrial facilities. This article only discusses identifying petroleum contamination on residential properties.

As is common to most investigative techniques, the ability to identify indications of contamination or the potential for contamination lays as much in keen observational skills as in technical competency.

Observations made by an inspector can be subdivided into the identification of contamination and the identification of conditions which indicate the potential for contamination.

Visual Identification of Overt Oil Tank or Gasoline Tank Leak Contamination

In many ways, the only evidence of overt contamination is the presence of free product itself on the ground or on water. Product on the ground is represented by a pool of petroleum; product on water is represented by a sheen, or film, present on top of the water.

Fuel oil and other less refined products are black or dirty brown, are viscous (thick) and do not readily permeate surfaces that generally impede the migration of water. Gasoline and other more highly refined petroleum products are not likely to be encountered as free product on the ground because they readily vaporize (move to a gas phase) and they permeate even surface such as concrete which generally impede the movement of water.

Fuel oil (and other less refined petroleum products) is observed as a blackish sheen on standing water. The oil will coalesce on the surface, even when physically separated. That is, when the water is disturbed, the petroleum product will reform a consistent sheen on top of the water. Because fuel oil (and most common petroleum products) have a specific gravity less than 1.0, they will for the most part float on top of the water and will not mix with the water column.

Gasoline is observed as a multi-colored sheen, representing the refined hydrocarbons as well as some of he chemical additives present in gasoline. While some of the compounds in gasoline will remain on the water surface (gasoline is an amalgam of over 100 different compounds), other constituents of gasoline (including xylene and MTBE, or methyl tertiary butyl ether) will more readily bind to water molecules and be transported through the water column with the movement of the water itself.

Indications of Likely Contamination by Oil or Gas Leaks

The most obvious indication that contamination is likely to be present is stained and odorous soil. These conditions require that the inspector determine that a petroleum product had been present on the surface and has become absorbed by the soil and is therefore still present but no longer as free product.

The presence of stained soil is evidence of contamination; however, laboratory analysis of the soil may be appropriate to document the type of petroleum present in the soil, the concentrations present (which will assist the inspector in determining if remedial actions are warranted) and the presence of any other compounds which may complicate clean-up.

Simply put, the presence of staining, while making it extremely likely that petroleum contamination exists on the property, is not sufficient. Laboratory analysis of the soil is necessary to rule out contamination by other compounds, including solvents or PCBs. At the same time, staining cannot be ignored and it is appropriate that stained soil be brought to the attention of the client so that additional steps can be taken.

A common location for staining is around the fill port or the vent pipe of the on-site tank(s). Spilling at these locations is common because of tank over filling as well as product dripping during delivery. Over many years, minor dripping can result in sizable soil contamination.

Spillage and leakage at fill and vent pipes is also common because for underground tanks these pipes are the only portion of the fuel storage system that is exposed. Oftentimes, these pipes are banged or moved, placing stress on the pipe joints, causing leaks. On residential properties, for example, fill ports are often located in the lawn, capable of being banged by lawnmowers.

It is important to remember that, empirically, most tank leaks actually result from a failure of the piping network. Piping joints (including the intersection of the pipe to the tank) are structurally the weakest component in the storage system and are often the point in the system most under stress through use and abuse.

A second indication of petroleum contamination is odor, without visual evidence of stained material. For example, petroleum odors may be evident upon entering a basement where no fuel tank is located. Appropriate actions include performing at least a preliminary search to determine the source of the odor.

Significant contamination can and has resulted from a leaky fuel line under concrete (many local building codes require that fuel lines be buried). Vapors in the basement may also be indicative of a leaking tank, with the vapors entering the basement through cracks in the foundation. A review of any information on the location, age, size and condition of the sub surface tank would be an appropriate next step. If insufficient information exists, it may be reasonable to suggest that the tank be precision tested.

Petroleum odors may also be present in the vicinity of the well, particularly if the casing to the well is partially open. The odor may be an indication of petroleum on the ground water, and a sample of the ground water for laboratory analysis would be an appropriate next step. Other Considerations

Properties may no longer store fuel but have tanks on the site as a result of prior use of heating oil or prior building use. For example, residential properties that have converted to natural gas may still have abandoned but not properly closed fuel oil tanks in the ground (some home heating oil tanks may be as large as 1,000 gallons).

Any residual fuel oil in these tanks represents a potential for site contamination. A vent pipe or fill port (the piping extending from the tank to release vapors or for access to fill the tank) may be visible near the building. Any pipes extending from the ground should be noted and their use clearly explained and documented by the property owner.

Finally, petroleum contamination on a property may not originate on the property that is being inspected; rather, the source may be from a nearby property. A complete inspection for possible petroleum contamination will include a visual inspection of nearby properties to document any conditions on these properties that may result in contamination of the initial property.

There are other sources of information which may be helpful. As mentioned above, releases of petroleum must be reported to the enforcing agency, and that agency in turn will compile records available to the public of these releases. Valuable information, including the date, location, type of product, and volume of product spilled is maintained by the enforcing agency.

Conclusions - a Summary of Oil Tank Leak Issues

Petroleum storage on any property, including residential properties, represents a potential liability. The costs that may be incurred to properly remediate a petroleum spill or tank leak can be significant. Costs for even minor leaks can be between $15,000 to $50,000.

For releases where ground water is affected, the costs of remediation can exceed $100,000. Regulations state that the primary party responsible for the costs of clean-up is the property owner, regardless of the owner's responsibility.

This makes detection prior to a purchase an important, in some cases invaluable, service. Unquestionably, the detection, evaluation and remediation of a petroleum spill or tank leak will require professionals in addition to the home inspector.

On residential properties, however, the inspector often is the individual who is initially involved and therefore the individual who will provide the initial service of detection.

Inspection for and reporting on environmental hazards are specifically excluded from the inspection steps required by the ASHI Standards of Practice. This article has provided information for home inspectors who, as permitted by the Standards of Practice, wish to provide additional specialized services such as the initial screening of a site for potential fuel spill issues.

Without proper detection, many of spills will continue to be undisclosed, resulting in unnecessary costs being incurred by innocent land purchasers.


Continue reading at OIL TANK LEAK & SIZE REPORTING or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

If your oil tank is leaking see OIL TANK LEAK ADVICE.

Suggested citation for this web page

BULK STORAGE OF PETROLEUM PRODUCTS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman