United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(OS-420 WF)
EPA 510-F-93-007
April 1993
oEPA UST Program Facts
Overview of the UST
Program
Definition of an underground storage
tank (UST)
For regulatory purposes, the U.S.
Environmental Protection Agency (EPA)
defines an UST as a tank and any
underground piping connected to the tank
that has 10 percent or more of its volume
(including pipe volume) beneath the surface
of the ground.
UST Program Scope
Approximately 1.6 Million Regulated Tanks
Petroleum
1,366,000
Used Oil
55,000
Other
121,500
Hazardous
Materials
23,500
Number of USTs in the United States
EPA estimates that there are from 5 to 7
million USTs nationwide. Most of these
USTs hold petroleum, and the rest hold
hazardous materials, used motor oil, or
other substances.
Why be concerned about USTs?
Storage tanks were buried to reduce the
potential for fire and explosion, and to
minimize human exposure to hazardous
substances. About 80 percent of
regulated USTs, however, were made of
bare steel, which can corrode and leak.
The greatest potential hazard from a
leaking UST is that the petroleum or
other hazardous substance can seep into
the soil and contaminate groundwater, the
source of drinking water for nearly half
of all Americans. A leaking UST can
present other health and environmental
risks, including the potential for fire and
explosion.
What Congress and EPA have done to
respond to concerns about USTs
In 1984, Congress responded to the
increasing threat to groundwater posed
by leaking USTs by adding Subtitle I to
the Resource Conservation and Recovery
Act (RCRA). Subtitle I required EPA to
develop a comprehensive regulatory
program for USTs storing petroleum or
hazardous substances.
Congress directed EPA to publish
regulations that would require owners
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and operators of new tanks and tanks
already in the ground to prevent and detect
leaks, clean up leaks, and demonstrate they
arc financially capable of cleaning up leaks
and compensating third parties for resulting
damages.
Congress banned the installation of
unprotected steel tanks and piping in 1984.
In 1986 it amended Subtitle I with the
Supcrfund Amendments and Rcaulhori/.ation
Act (SARA).
SARA created the Leaking Underground
Storage Tank (LUST) Trust Fund, which is
to be used for two purposes:
• To pay for cleanups at sites where
the owner or operator is unknown,
unwilling, or unable to respond, or
which require emergency action;
• To oversee cleanups by responsible
parties.
SARA also imposed financial responsibility
requirements.
Tanks that come under EPA regulations
Approximately 1.6 million USTs arc subject
to EPA regulation. They arc buried at more
than 600,000 sites in the United Slates and
its territories. Owners of USTs include:
• Marketers - who sell petroleum to
the public. Service stations and
convenience stores arc typical
marketers.
• Non-marketers - who own tanks for
their own use. Manufacturers, fleet
service operators, and local
governments are examples.
Tanks excluded from EPA regulations
Some tanks that meet EPA's definition of
an UST are exempted by law. They
include:
• Farm and residential tanks
holding 1,100 gallons or less of
motor fuel used for non-
commercial purposes;
Tanks storing heating oil used on
the premises where it is stored;
Tanks on or above the floor of
underground surfaces, such as
basements or tunnels;
Septic tanks and systems for
collecting stormwater and
wastewater;
• Flow-through process tanks;
• Tanks holding 110 gallons of
fluid or less; and
Emergency spill and overfill
tanks.
Federal regulation of USTs
In 1988, EPA issued regulations setting
minimum standards for new tanks and
requiring owners of existing tanks to
close, replace, or upgrade them. Tank
owners and operators are required to
meet leak detection requirements, and to
show they have financial resources to pay
for cleanups should a leak or spill occur.
The UST regulations are divided into
three sections: technical requirements,
financial responsibility requirements, and
state program approval objectives.
• Technical requirements.
EPA's technical regulations for
USTs are designed to reduce the
chance of releases from USTs,
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detect leaks and spills when they
do occur, and secure a prompt
cleanup. To meet the
requirements, owners must
upgrade or replace existing LIST
systems by 1998. Either way,
tanks must have leak detection
and leak prevention components.
(See Leak Prevention, Leak
Detection, and Cleanup fact
sheets in this series.)
Financial responsibility
regulations.
The financial responsibility
regulations ensure that, in the
event of a leak or spill, an owner
or operator will have the
resources to pay for costs
associated with cleaning up
releases and compensating third
parties. (See Financial
Responsibility fact sheet in this
series.)
State program approval
objectives.
EPA recognizes that, because of
the large size and great diversity
of the regulated community, state
and local governments arc in the
best position to oversee USTs.
Subtitle I of RCRA allows state
UST programs approved by EPA
to operate in lieu of the federal
program, and EPA's state
program approval regulations set
standards for state programs to
meet. (See State UST Programs
fact sheet in this series.)
State regulations on USTs
States may implement regulations that are
stricter than the federal government's.
People who arc interested in requirements
for USTs should contact their state UST
program for information on state
requirements.
Overview of the UST Program is one in a series
of fact sheets about underground storage tanks
(USTs) and leaking USTs. The series is
designed to help EPA, other federal officials, and
stale authorities answer the most frequently
asked questions about USTs with consistent,
accurate information in language the layperson
can understand. Keep the fact sheets handy as a
resource. This fact sheet addresses federal
regulations. You may need to refer to applicable
state or local regulations, as well. For more
information on UST publications, call the
RCRA/Superfund Hotline at 800 424-9346.
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