A Primer on Petroleum Bulk Storage Tanks and Petroleum Contamination of Property InspectAPedia® -
An overview of oil storage tank regulations governing petroleum bulk storage and then
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?
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This article (1) presents basic
information on the regulations governing petroleum bulk storage and then (2)
identifies conditions and overt indications of petroleum contamination. The
article provides information on
indications of site contamination.(3) --
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:
failure of a precision test on a tank, implied (not directly specified) to be
any test result showing a loss in product volume greater than 0.05 gallons per
hour
encountering, through sub surface exploration or other means, of petroleum
contaminated soil and/or ground water
significant staining of surface soils indicating the spillage of petroleum
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
detailed specifications on the installation of new tanks, referencing National
Fire Protection Association (NFPA) requirements
deadlines for installation of leak detection devices for all underground
storage tanks
spill containment for all aboveground tanks storing more than 10,000 gallons on
a permanent basis; and
periodic monitoring of the volume of product in an underground tank and the
condition of the visible portions of aboveground tanks.
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.
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Primer on Petroleum Bulk Storage Tanks & Petroleum Contamination of Property Paul H. Ciminello, ASHI Tech. Journal, Vol.3 No.1 Spring 1993, p 35-39 [Original text of this article, with updates, edits and extensions by InspectAPedia.com]. Paul H. Ciminello is the president of
Ecosystems Strategies, Inc., an environmental consulting firm in Poughkeepsie,
NY. Reprints of the ASHI Technical Journal can be purchased from ASHI, the American Society of Home Inspectors,
at www.ashi.com.
"Leaky Oil Tanks," D.J. Friedman, ASHI Technical Journal, January 1992 p. 42-43.
Reviewers of this article included: Stephen Gladstone, Daniel Friedman
Footnotes for this article
1. U.S. Tank Tech, Morris Morgan, Carmel NY, presentation to NY Metro ASHI,
Chapter Seminar, Elmsford, NY, March, 1992.
2.The ASHI Standards of Practice specifically exclude environmental site
audits from the inspection topics which are required. ASHI Inspectors are
permitted to exceed the Standards, with the recommendation that inspectors who
do so should assure they have proper qualifications and training.
3.The authors reside and primarily work in New York State; therefore, the
information provided will reference New York State regulations as well as
federal regulations.
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