United States	^ ,
Environmental Protection Aqencv inoa
Washington DC 20460

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The Leaking Underground
Storage Tank Problem
Owning, installing, and living near underground
tanks is becoming more and more complicated
because of what we are learning of the serious-
ness and scope of leaking underground storage
systems. Tank owners should be fully informed
about good tank management practices for old or
new tanks. Elected officials and government per-
sonnel should be ready to draft or enforce tank
regulations. Citizens should be informed enough
to recognize the signs of a leaking tank and help
push for effective regulations. This brochure pro-
vides a brief guide to the causes of leaks and
what to do to prevent or correct them. It pays to
take underground storage systems seriously by
investing the time and precautionary measures
necessary now to avert a major problem later.
It's Pervasive
Gasoline and other toxic chemicals leaking from
underground storage tanks or piping are one of
the most common causes of groundwater pol-
lution. National estimates for numbers of existing
underground storage tanks range from 5 to 7
million. According to current estimates, 15 to 20
percent of them are probably leaking. Many are
leaking into the groundwater and, in some cases,
toward an unsuspecting community's drinking
water supply.
It's Hidden
Gasoline is usually stored in underground tanks
(for fire prevention reasons) at locations such as
gas stations, convenience stores, bulk storage
facilities, Federal, State and local motor pools,
airports, farms, marinas, and bus and cab com-
panies. In addition, fuel oil is stored in millions of
small underground tanks located at private resi-
dences, apartments, institutions and businesses
throughout the United States. If petroleum leaks
out of any of these storage systems, it may con-
taminate groundwater resources and remain

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undetected for years with the potential for doing
irrevocable damage to private or public water
supplies.
It's In The Groundwater
Approximately 50 percent of the United States
population relies on groundwater as their principal
or partial source of drinking water. This reliance
on groundwater is increasing as surface water
supplies become less available. A leak of one
gallon of gasoline can render a million gallons of
water undrinkable.
Once in the ground, the leaked gasoline takes
three forms: 1) as a free product mass coating the
soil, it moves downward and outward on top of the
water table; 2) its water soluble components
dissolve into, and move with, the groundwater and
can lead to human exposure via ingestion and
skin absorption; and 3) as a vapor, it fans outward
leading to possible exposure via inhalation of
fumes.
During any groundwater restoration effort, an
alternative water supply must be provided. Res-
toration of a badly contaminated groundwater
supply is time consuming, expensive and not
always technically feasible. Because any one o f
the millions of existing tanks has the potential to
cause a serious problem, careful management
and monitoring of tanks and piping is imperative.
It Can Be Hazardous To Your Health
And Safety
The American Petroleum Institute (API) has sug-
gested that member companies post a notice at
service stations warning that prolonged exposure
to vapors can cause serious illness. Most people
are aware that gasoline is volatile and, therefore,
a safety hazard. But because we have coexisted
with it for decades, many people are not aware
that gasoline can also be a health threat, espe-
cially when its components are in drinking water or
its fumes invade homes or businesses.

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Gasoline is among the most toxic of substances
common to our everyday living. So far, about 400
different compounds have been identified in gas-
oline. A few of these have been shown to induce
cancer in laboratory animals, and one, benzene, is
a known human carcinogen. Toxicological and
limited human studies have found gasoline com-
ponents to cause such health problems as ane-
mia, nervous system disorders, kidney disease,
cancer, and lead poisoning.
The Costs Of Inaction
The effects of leaking underground storage tanks
or piping can be costly and may have an impact
on many people. Simply assessing the extent of a
contamination problem can cost $10,000 or more.
A leak caught early and still within the property
boundary may cost between $3,000 and $30,000
to clean up. Depending on site-specific
conditions, the cost of a leak migrating beyond

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property boundaries can soar into hundreds of
thousands - in some cases even millions -- of
dollars for cleanup and compensation to injured
parties. Litigation will add to these costs.
The major oil companies were the first to identify
the tank failure problem and aggressively initiate
expensive tank replacement and protection pro-
grams for company-owned retail stations. Some
of these companies have experienced lawsuits
and costly cleanup programs resulting from leaks
detected too late. However, many of the smaller
independent distributors and station operators do
not have the resources to absorb these costs or
the costs of undertaking extensive tank replace-
ment programs.
Many communities have experienced some kind
of problem with underground storage systems.
When the issue of who will pay for these liabilities
arises, the affected communities have had to bear
much of the financial burden.
Today few tank owners carry insurance for leaks.
But Congress has now mandated a minimum of
one million dollars in financial coverage for each
owner, which will take effect in 1988. Owners or
operators can show that they have financial cov-
erage in many ways, ranging from a traditional
insurance policy, to State assurance funds, or risk
retention pools. The key is for tank owners to
show that they can cover the costs of a leak, at
least up to one million dollars.
Why Underground Storage Systems Leak
The major causes of leaks from underground tank
systems now are known to be tank failures, leaks
in piping or fittings on the top of tanks, and spills
caused by overfilling.
Steel Tanks: The late 1950's and early 1960's
were boom times for the installation of bare steel
or asphalt-coated underground petroleum storage
tanks which were not protected against corrosion.
It is now illegal to put these tanks in the ground.
While age by itself is a poor indicator of tank inte-
grity, it may be one of the few practical indicators

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State or local regulatory agencies can use to
establish mandatory replacement and testing
schedules for storage systems. Though all new
steel tanks are now required to have corrosion
protection, check with your State government on
what applies to tanks already in the ground.
Fiberglass Tanks: By the mid 1960's, fiberglass
reinforced plastic (FRP) tanks had become estab-
lished as an underground storage system alter-
native. While FRP tanks do not rust, they are
subject to structural failure. Installation is critical
because the integrity of FRP tanks depends
especially on support of the backfill. In addition,
FRP tank owners must be sure the stored product
is chemically compatible with the tank. Tank
manufacturers can supply this information.
Piping: A recent study indicates that most leaks
do not come from the tank portion of the system;
in fact, this study found that piping leaks and spills
are more common. Piping fails because of corro-
sion, poor installation, accidents, and natural
events such as frost heaves.
Prevention Is The Best Cure
/4s each leaking tank empties its contents into the
earth, our quality of life is jeopardized. Immediate
attention to this problem is our best hope of curb-
ing the widespread contamination of groundwater
supplies. Tank owners and operators, local
governments, and others can ward off future
crises by becoming leak preventors and leak de-
tectives. There are four fundamental strategies
tank owners can use to prevent groundwater
contamination: 1) careful selection of new under-
ground storage facilities or replacement options,
2) proper installation of the underground storage
system, 3) effective leak detection and spill pre-
vention, and 4) quick and thorough cleanup if a
leak has occurred. Municipal officials should
also be aware of the problem, learn the location of
all storage tanks within their jurisdictions, identify
and provide for the removal of abandoned tanks,
and develop a strategy for protecting and
managing community drinking water resources.

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Concerned citizens can be key players in this
effort by knowing the source of their drinking
water and the potential threats to its quality. They
can also let local tank owners know of their con-
cern and participate in the development and
enforcement of regulations.
Selecting An Underground Storage
System
When installing tanks and piping, it is imperative
to use systems that are designed to prevent
leaks. These systems can be fiberglass or steel
and can use double-walled tanks and piping.
Fiberglass tanks do not rust, but they can crack,
and the costs of the tank and proper installation
are generally higher.
There are two types of modern steel tanks: those
with a noncorrodible coating and cathodic protec-
tion, and those with fiberglass-reinforced plastic
cladding, known as composite tanks. Steel tanks
are stronger and easier to install than fiberglass
tanks, but their coatings are subject to damage
during handling, transport or installation. Since
any exposed steel surface is subject to very rapid
localized corrosion, any damage to the tanks must
be repaired before they are buried.
Double-walled tanks and piping: These provide
the greatest protection against leaks and can be
easily combined with an automatic monitoring
system to provide continuous early leak detection.
By using a double-walled tank, or another form of
secondary containment, such as a liner in the pit,
a leak can be discovered before the gasoline ever
reaches the soil or groundwater.
Leak Detection
Leak detection can be done in a variety of ways
and at various costs. There are, however, two
basic ways to approach leak detection: 1) leak
monitoring systems, and 2) tank and pipe testing.
Check with your State or local government for
specific requirements. Inventory control can be
helpful in combination with monitoring or testing.
Finally, constant vigilance over the visible parts of

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the fuel storage and pumping system and an
awareness of operational abnormalities can also
help detect leaks.
Monitoring: Well-designed liquid and vapor
monitoring systems can detect most leaks in
tanks or piping before the product moves far
enough to do environmental or public health
damage. Most systems detect leaked product by
means of observation wells and the select use of
sensors located within the tank excavation area.
Monitoring systems located in double-walled
tanks can detect leaks before they escape into
the environment.
Tank and Pipe Testing: Tank testing cannot be
done on a continuous basis and will only indicate
a tank or pipe leak at the time of the test... not
a leak that starts the day after. Tanks can be
inspected and tested in several ways. One com-
mon test is to place the tank, piping and contents
under hydraulic pressure and check for tightness.
This procedure must be performed at certain
intervals as required by many State or local gov-
ernments, or when inventory losses or monitoring
systems indicate a possible leak.
Inventory Control: Inventory control alone does
not adequately detect leaks; but, if used together
with another leak detection method, it can be
quite helpful in keeping track of stored product.
Inventory records should be methodically main-
tained on a daily basis. This is done by com-
paring a running total of product deliveries and
sales with measurements of the amount of pro-
duct in the tank at the beginning and end of each
business day. Periodic inventory reconciliation
will take into account loss from other sources
such as delivery discrepancies, temperature
change, sales error or pilferage. Additional re-
conciliation may be done by incorporating such
techniques as statistical analysis.

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The Law
Regulations addressing environmental and public
health concerns for underground storage systems
are being developed by Federal, State and local
governments. In November 1984, Congress di-
rected the EPA to initiate a major Federal pro-
gram to regulate all underground storage of petro-
leum products and hazardous substances. These
regulations include leak detection and leak pre-
vention, and will have a range of requirements
such as standards for design, construction, instal-
lation, repair, closure, and financial responsibility.
Regulations requiring tank registration are already
in place.
When it's too late for leak prevention, the Federal
Government and most States have authority to
respond to leaks from underground storage
systems by taking or ordering appropriate reme-
dial actions. Some States have strict liability
provisions against tank owners responsible for
leaks. A 500 million dollar Trust Fund established
by Congress in 1986 will also help pay for cleanup
under certain circumstances.
A leaking gasoline storage tank is unearthed.

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For More Information
The Safe Tank Campaign consists of a nationwide
network of people concerned about the problem
of leaking underground storage tanks. The
Campaign is founded on the belief that wide-
spread grassroots community education and
involvement is necessary to overcome this threat
to the environment and human health. The
Campaign helps communities learn from each
other's problems and solutions and is presently
compiling information and resources from around
the country. To become a part of the network, or
simply to learn more, please write to:
Safe Tank Campaign
1525 New Hampshire Avenue, N.W.
Washington, D.C. 20036
(202) 745-4870.
This brochure is based on a 1985 version
prepared by the New England Interstate Water
Pollution Control Commission (NEIWPCC) under
a grant from the U.S. Environmental Protection
Agency. It has been revised and updated by the
Environmental Task Force, January 1988.

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