EPA 700/F-84/009
oEPA
IS
al Protection
Office of
Toxic Substances
Washington, DC 20460
September 1984
Leaking Underground
Storage Tanks Containing
Motor Fuels: A Chemical
Advisory
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What
Can
Leaks
Do?
Leaks Can Cost Money
A tiny leak from an underground storage tank or pipe
may hardly seem worth worrying about, but it can
cost you money. A leak as small as one-half drop per
second (0.05 gallons per hour) causes losses of 438
gallons a year; a leak of one gallon per hour will result
in losses of 8,760 gallons a year. Losses like this can
add up to a lot of money.
Leaks Can Cause Damage
Half the population of the United States depends on
groundwater from community or private wells for their
water supplies. Motor fuels that leak from tanks and
1 ipes can enter and contaminate these groundwater
and drinking water supplies. Leaks can also damage
underground structures (such as sewer lines and
telephone cables); present fire or explosion hazards;
and damage crops, livestock, and wildlife. Even in
small amounts, long-term exposure to motor fuels
may cause health problems. Water can also flow into
the tanks from these leakholes and contaminate your
motor fuel.
Leaks Can Result in Liability Claims
Leaks that are not discovered for a long time can
cause widespread damage. Early detection of leaks
can help minimize damages and cleanup costs. If you,
the tank owner or operator, are sued for damages
resulting from a leaking tank or pipe, the courts may
hold you responsible—even if you didn't know about
the leak. In some cases, the courts have ordered tank
owners and operators to pay for clean up, soil
decontamination, alternative water supplies, and even
to buy homes that have been contaminated. These
costs to the tank owner or operator can run into
millions of dollars.
What Causes Leaks?
Leaks from tanks can be caused by improper
installation or breakdown of the materials of which
the tank or pipes are made. Breakdown of steel tanks
or pipes by corrosion or rupture of fiberglass tanks are
among the major causes of leaks. Tank and pipe
corrosion may be affected by many different factors
including spills of product, improper or infrequent
maintenance, soil type and moisture, or severe
weather conditions.
Tanks made of unprotected steel will corrode. The
majority of unprotected steel tanks begin to leak
when they are anywhere from 2 to 20 years old. Steel
tanks with corrosion protection can also corrode if the
corrosion protection is not correctly installed or
maintained. Fiberglass tanks will not corrode on the
outside, but these tanks are not as strong as steel
tanks and may begin to leak if they are not properly
installed.
Do You Have A Leak?
There are many ways to test for leaks in underground
tanks and pipes. The three basic methods for
detecting leaks are: (1) inventory review, (2) tank
leak testing, and (3) leak effects monitoring. EPA has
reviewed a number of methods for detecting leaks.
These reviews are included in the document "More
About Leaking Underground Storage Tanks: A
Background Booklet for the Chemical Advisory." You
can get a copy of this document by calling EPA's toll-
free number, 800-424-9065.
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Inventory Review
Inventory review is a practical and inexpensive way
for owners and operators of underground storage
tanks to first discover whether there is a loss of
product. The inventory review requires very little extra
effort—for metered pumps, daily measurements of
motor fuel levels can be compared to the amount
dispensed. For both metered and unmetered pumps,
inventory review should be done on a regular basis. If
the inventory review shows a continuing loss, the
operator or owner should use another, more exact
testing method before finally deciding that there is a
leak problem.
A step-by-step guide to one inventory review method
is available from EPA by calling toll-free 800-
424-9065. Petroleum organizations or your motor fuel
supplier can also give you more information on
inventory review and leak detection tests. The
American Petroleum Institute's (API) Publication No.
1621 (1977), "Recommended Practice for Bulk Liquid
Stock Control at Retail Outlets" provides detailed
information on inventory review. This publication can
be obtained at a cost of 75
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What Should You Do If You
Have A Leak?
Underground Tank Replacement
and Repair
Once a leak is discovered, tank owners generally have
two basic options: (1) to remove and replace existing
tanks and pipes, or (2) repair existing tanks or pipes.
Repair of tank or pipe leaks may include fixing a leak
and installing a corrosion protection system, or
applying an internal lining.
No matter whether you are thinking about putting in
new storage tanks or protection systems for tanks
already in the ground, you should remember that "an
ounce of prevention is worth a pound of cure." While
the installation of tanks and pipes with leak
prevention or monitoring systems may cost 20 to 100
percent more than unprotected steel tanks, the
protected and fiberglass tanks may last longer and
typically have longer warranties. Warranties for
protected and fiberglass tanks may be for 20 to 30
years; most unprotected steel tanks have only a one
year warranty on workmanship defects.
Because fiberglass tanks are not as strong as steel
tanks, they must be properly installed to avoid their
rupturing from uneven loads. There has also been
some concern about the compatibility of existing
fiberglass tanks and pipes with some of the alcohol
fuels or alcohol-blended fuels. If you have questions
about the compatibility of a product in a fiberglass
tank or piping, contact the representative for your
fiberglass tank company.
Other types of tanks to consider are asphalt coated
steel, fiberglass coated steel, fiberglass coated
double-walled steel, and epoxy coated steel. These
different types of tanks offer varying degrees of
protection at a wide range of costs. There is also a
variety of piping available.
Reporting Leaks
Underground tank systems may be subject to Federal,
State, or local regulations. These regulations vary
considerably. Many States have adopted uniform fire
code requirements for tank permits, specifications,
and installation procedures. Recently, several states,
such as Maryland, Florida, and California have
adopted laws to protect groundwater by requiring leak
detection systems. Several States also require clean-
up of leaks once they are discovered. Many localities
are also issuing regulations that deal with leaking
underground storage tanks. You should become
familiar with the Federal, State, and local regulations
that apply to you. If you discover a leak, you should
promptly report it to the appropriate Federal, State or
local authority, such as a fire marshal, civil defense
official, or natural resource agency. If the leak
appears to pose a threat of contamination to a
drinking water well, the health department should be
notified.
Is Insurance Available?
Many tank owners and operators are covered by
Comprehensive General Liability (CGL) policies. These
policies generally cover pollution claims resulting from
"sudden and accidental" occurrences. Even though
some CGLs have been modified recently to cover
gradual leaks or "non-sudden pollution losses," these
owners and operators should not assume that their
CGL policy covers gradual leaks of motor fuel from
underground storage tanks or pipes.
In cases where tank owners are covered by CGL
policies, some insurance companies have shown a
willingness to modify the policies to cover gradual
pollution. Usually, however, tank owners and
operators must purchase a separate pollution liability
policy (sometimes known as environmental
impairment liability) to obtain protection for gradual
leaks. For more information on obtaining leak
insurance, contact your insurance broker, a national
petroleum marketing trade association (or an
equivalent State association), or the Pollution Liability
Insurance Association.
vvEPA
United States
Environmental Protectioi
Agency
Third-Class Bulk Rate
Postage and Fees Paid
EPA
Permit No. G-35
Office of Toxic Substani
TSCA Assistance Office
Washington DC 20460
Official Business
Penalty for Private Use
$300
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