oEPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
DIRECTIVE NUMBER:
9610.2
TITLE: Clarification of the Definition of "Underground
Storage Tank"
APPROVAL DATE:
EFFECTIVE DATE: <4l?t?
-------
&EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
DIRECTIVE NUMBER:
9610.2
TITLE: Clarification of the Definition of "Underground
Storage Tank"
APPROVAL DATE:
EFFECTIVE DATE:
ORIGINATING OFFICE: OUST
Q FINAL
D DRAFT
STATUS:
REFERENCE (other documents):
OS WER OS WER OS WER
VE DIRECTIVE DIRECTIVE Dl
-------
x°/EPA
United States Environmental Protection Agency
Washington, DC 20460
OSWER Directive Initiation Request
Interim Directive Number
9610.2
Originator Information
Name of Contact Person
Virginia Cummings
Mail Code
WH-562A
Telephone Number
382-7925
Lead Office
D OERR
D OSW
l±l OUST
n OWPE
D AA-OSWER
Approved for Review
Signature of Office Director
Date
Title
Clarification of the Definition of "Underground Storage Tank"
Summary of Directive
List of terms to clarify the definition of "underground
storage tank" and related words. This list is to be used by
HQ and Regional staff as well as State personnel in answering
questions from tank owners about whether they must notify or
not. The clarification of these terms is badly needed to clear
up confusion over the interpretation of what is an underground
storage tank.
This list of definitions represents the Agency's policy
until we propose them in the Federal Register and take public
comment on them.
Type of Directive {Manual. Policy Directive. Announcement, etc.)
Policy directive
Status
D Draft
El Final
CU New
I I Revision
Does this Directive Supersede Previous Directive(s)? | | Yes
If "Yes" to Either Question. What Directive (number, title)
No Doe's It Supplement Previous Directive(s)? | | Yes [Jj No
Review Plan
D AA-OSWER EE3 OUST
D OERR D OWPE
I I OSW I—I Regions
D OECM
D OGC
O OPPE
D
Other (Specify)
This Request Meets OSWER Directives System Format
Signature of Lead Office Directives Officer
Date
.V
Signatures! OSWER Directives Officer
Date
EPA Form 1315-17(10-85)
-------
.„--,«. OSWER Directive9610'2
• ^^
* ^^ \ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
V" "
APR 7
MEMORANDUM
SUBJECT: Clarification of the Definition of
Jndergro,u^id Storage Tank"
OFFICE OF
SOLID WASTE AND EMERGENCY RESPONSE
FROM: /P. Winston Po/ter
(ssistant Administrator
TO: EPA Regional Administrators
Please find attached to this memo definitions of key
terms for the purpose of implementing the notification
process for underground storage tanks. As the May 8 deadline
for notification approaches, it has become clear that we need
consistent answers for the questions frequently asked by the
States and regulated community.
Please forward a copy of this information list to each of
your states. I have provided the list to the RCRA/ Superfund
hotline.
Should you have any questions concerning these terms,
or if you are aware of remaining definitional issues, please
contact Virginia Cummings of my staff (382-7925) or
Carrie Wehling of the General Counsel's office (475-8067).
Attachment
-------
9610.2
LIST OF UST DEFINITIONS AND EXEMPTIONS
I. Under Section 9001 of the 1984 RCRA Amendments,
Underground Storage Tank means "any one or combination
of tanks (including underground pipes connected thereto)
which is used to contain an accumulation of regulated
substances and the volume of which (including the volume
of the underground pipes connected thereto) is 10 percent
or more beneath the surface of the ground."
Definition
1. tank is a stationary device which is constructed
primarily of non-earthen materials (e.g., wood, concrete,
steel, plastic) which provide structural support.
Discussion
The basis of this definition is the definition of tank
under Subtitle C of RCRA (40 CFR 260.10).
Under this definition, just about every type of container
(e.g., small metal boxes, underground sumps, and dump
tanks) would be considered tanks. The fact that they are
small or unusual tanks may not be of particular relevance
when the issue is releases to proximate groundwater sources,
Definition
Discussion
2. used to contain an accumulation of regulated substances,
An underground storage tank that contains regulated
substances for any period of time, no matter how small
the amount, is within the jurisdiction of Subtitle I.
For the purposes of UST jurisdiction, there is no
"de minimus" or small quantities exclusion, although
such an exclusion is likely to be included in later
technical regulation of USTs.
Definition
3. pipes connected thereto
Connected piping includes all piping connected to a tank
system through which regulated substances flow. For the
purpose of determining how much piping is connected to
any individual tank, the piping which joins the two tanks
should be allocated equally between them.
-------
9610.2
(2)
Discussion
The definition of connected piping addresses two issues:
(1) where the connected piping begins, and (2) how the
connected piping should be allocated between tanks. To
be consistent with the RCRA Subtitle C tank rules, the
starting point of the "connected piping" is the point
at which the regulated substance is introduced into the
system.
This means that if there is an exempt tank between the
point of introduction and an underground storage tank,
the connected piping is allocated between them. Equal
allocation of piping between tanks is also the basis of
determining whether the volume of an individual tank is
10% or more beneath the surface of the ground.
Definition
4. beneath the surface of the ground
A tank is 10% or more beneath the surface.of the ground
if its volume (including the volume of its connected
piping) is either (1) 10% or more below ground surface
or grade, or (2) 10% or more beneath ground surface or
otherwise covered with material so that expeditious
inspection is precluded.
Discussion
This definition addresses two situations in which a tank
would be considered to be underground. First, a tank
may be considered an underground storage tank even if
10% or more of its volume is not covered by ground
material as for example a tank that is in a below grade
containment area (such as a swimming pool or a ditch).
Second, if 10% or more of the tank volume is covered by
ground material, either below or above grade, the tank
is within UST jurisdiction. This means that tanks that
are above ground but mounded over with dirt (to comply
with local fire codes) are within UST jurisdiction.
II. The definition of underground storage tank exludes
nine types of tanks which would otherwise be subject
to UST regulation.
A. The first group of tanks excluded by the statute is
"farm or residential tanks of 1,100 gallons or less
capacity used for storing motor fuel for noncommercial
purposes."
-------
9610.2
(3)
Definition
Farm tank is a tank located on a tract of land devoted
to the production of crops or raising animals, including
fish, and associated residences and improvements.
Discussion
The definition of farm is based upon that used by the
Internal Revenue Service in connection with tax exclusions
for farmers. To be exempt from UST jurisdiction, a farm
tank must be located on the farm property. "Farm" includes
fish hatcheries and rangeland. "Farm" does not include
laboratories where animals are raised, land used to grow
timber, or pesticide aviation operations.
Definition
Discussion
Residential tank is a tank which is located on property
primarily used for dwelling purposes.
The language of the exclusion indicates Congressional
intent to remove from UST jurisdiction small gasoline
tanks located on property used for dwelling purposes
(i.e., residential property). A private school storing
motor fuel on site for school buses would not be excluded
from UST jurisdiction because the primary use of the
property is not residential.
Definition
Discussion
Noncommercial purposes means where the motor fuel is
not for resale.
The exclusion is limited to motor fuel stored on farmland
or residential property and which is not for resale.
Tanks at gas stations located on "residential" or "farm"
property as defined above are not excluded because the
motor fuel is stored for resale.
B. The second group of tanks excluded from UST jurisdiction
by statute is tanks used for storing heating oil for
consumptive use on the premises where stored.
(These definitions are forthcoming.)
-------
9610.2
(4)
Definition
C. The third group of excluded tanks covers any "septic
tank."
A septic tank is a water-tight covered receptacle designed
to receive or process, through liquid separation or
biological digestion, the sewage discharged from a building
sewer. The effluent from such receptacle is distributed
for disposal through the soil. Settled solids and scum
are pumped out periodically and hauled to a treatment
facility for disposal.
Discussion
The definition of septic tank is based on common and
technical usage. There are two issues which have been
raised with respect to the definition of "septic tank":
(1) does the septic tank exclusion include all septic
tanks or only residential ones? (2) does the exclusion
refer only to a septic tank or does it refer to the septic
system? Based on the history of this provision, the
"septic tank" exclusion applies to all septic tanks. In
addition, the entire septic system which may include other
types of tanks such as a distribution box, dosing tank, and
grease trap - is exempt.
Definition
Discussion
D. The fourth exclusion covers any "pipeline facility"
(including gathering lines) regulated under (1) the Natural
Gas Pipeline Safety Act of 1968 (49 U.S.C. App. 1671, et
seq.), (2) the Hazardous Liquid Pipeline Safety Act of
1979 (49 U.S.C. App. 2001, et seq.), or (3) which is an
intrastate pipeline facility regulated under State laws
comparable to the provisions of laws referred to above."
Pipeline facilities include without limitation, new and
existing pipe rights-of-way and any equipment, facility, or
building used in the transportation of gas (or hazardous
liquids, which includes petroleum and any other liquid
designated by the Secretary of Transportation) or the
treatment of gas or designated hazardous liquids during
the course of transportation.
This definition was borrowed from the Natural Gas Pipeline
Safety Act of 1968 and the Hazardous Liquid Pipeline Safety
Act of 1979. "Pipeline facility" may also include any
such facility as defined and regulated under State laws
comparable to these two federal statutes.
-------
9610.2
(5)
Definition
E. The fifth exclusion covers any "surface impoundment, pit,
pond, or lagoon."
A surface impoundment is a natural topographic depression,
man-made excavation, or diked area formed primarily of
earthen materials (although it may be lined with man-made
materials).
Discussion
This definition was borrowed from Subtitle C (40 CFR 260.10)
Because the statute uses the somewhat specialized Subtitle
C terms "surface impoundment, pit, pond, and lagoon" to
define this exclusion, it is likely that Congress also
intended to borrow the meaning of surface impoundment from
Subtitle C.
Examples of structures excluded from UST jurisdiction are
holding, storage, settling, and aeration pits, ponds, and
lagoons.
Definition
F. The sixth exclusion covers a "storm water or waste water
collection system."
A "stormwater or wastewater collection system" is defined
as piping, pumps, conduits and any other equipment used to
receive and convey surface water runoff resulting from
precipitation or domestic, commercial, and industrial
wastewater. The collection of stormwater or wastewater
must be directed towards conveyance, and does not include
storage or treatment of stormwater or wastewater
except where incidental to conveyance.
Discussion
Excluded from UST jurisdiction under this definition are
tanks associated with stormwater or wastewater sewer
systems. Tanks that are part of wastewater collection
systems at industrial facilities are also excluded under
this definition so long as the tanks are primarily used
for collection and conveyance of wastewater or storm
water. Tanks used for storage or treatment of stormwater
or wastewater not incidental to collection and conveyance,
such as wastewater treatment tanks at industrial facilities
or municipal water treatment works, are not excluded under
this definition.
This definition excludes sumps when they are part of
stormwater/wastewater overflow or conveyance.
-------
9610.2
(6)
Definition
G. The seventh exclusion covers any "flow-through process
tank."
A flow through process tank is a tank which forms an
integral part of a manufacturing process and through which
there is a steady or uninterrupted flow of materials
during operation of the manufacturing process. The term
"flow through process tank" does not include tanks used to
store regulated substances prior to their introduction
into the manufacturing operation, or to store regulated
substances as products or by-products from the manufacturing
process.
Discussion
There are two key concepts associated with this term: (1)
"flow-through" means steady or regular flow. That is, the
fluid level is subject to constant change during operation
of the process. (2) "process" means integral to manufacturing
process (as opposed to a process in the tank).
Concerning the first concept, defining "flow through" as
including regularly occurring flows as well as continuous
flows the use of a retention-time limitation was rejected
on the grounds that this would be too complicated. The
dividing line between "flow through" and storage would be
very difficult to determine.
Concerning the concept of "process", the only tanks that
are excluded as flow-through process tanks are those tanks
that are integral to the manufacturing process. This means
that tanks that hold raw materials prior to processing and
tanks holding products, byproducts, or wastes after the
processing may be subject to UST jurisdiction.
H. The eighth exclusion covers "liquid trap or associated
gathering lines directly related to oil or gas production
and gathering operations."
Definition
The liquid trap exclusion refers to tanks used for the
purpose of the collection and removal of water and other
liquid impurities from oil and gas during oil and gas
production operations and their attendant production lines,
-------
9610.2
(7)
Discussion
Although liquid traps are often used in activities other
than oil and gas production, the only type of liquid trap
excluded from UST jurisdiction under the statute is a
liquid trap used for the purpose of separating unused oil
and gas liquids from water at oil and gas producing
facilities.
However, not all tanks at oil and gas producing facilities
will qualify for this exclusion. For example, after removal
of oil in a liquid trap, the water (containing some oil
residue) may be stored prior to discharge. This oily water
would be subject to UST jurisdiction if stored in an under-
ground storage tank. Tanks associated with gas delivery
lines that connect the liquid trap to an underground storage
tank may be subject to the pipeline facilities exclusion.
(See definition of "pipeline facilities" above.)
"Liquid traps" such as grease and oil traps at gas stations
as well as methane gas produced at landfills are not within
this exclusion and would be subject to UST jurisdiction.
Definition
I. The ninth exclusion covers "storage tanks situated in an
underground area (such as a basement, cellar, mine working,
drift, shaft or tunnel) if the storage tank is situated
upon or above the surface of the floor."
Underground area means an underground room, such as a base-
ment, cellar, shaft or vault, providing enough space for
external physical inspection of the tank situated on or
above the surface of the floor.
Discussion
This exclusion applies to "underground rooms" where tanks
are located on or above the floor surface. The purpose of
this exclusion is to remove from UST jurisdiction tanks
which are technically underground but which are in a
practical sense no different from above ground tanks. They
are situated so that, to the same extent as tanks above
ground, physical inspection for leakage is possible. Thus,
the requirement to be able to physically inspect the tank
for leakage is consistent with the purpose of this exclusion,
Tanks located in a below grade structural vault, cellar,
basement, mine or other underground room would be subject
to the UST exclusion as long as the tank sits on or above
the surface of the floor and there is sufficient space
to enable physical inspection of the tank.
------- |