&EPA
       United States
       Environmental Protection
       Agency
      Source  Water  Protection
               Practices  Bulletin
Managing  Above Ground  Storage Tanks to
 Prevent Contamination  of Drinking Water
   Inside this issue:
 Why is it Important  2
 to Manage ASTs?

 Available Prevention  2
 Measures

 Additional         4
 Information
   Basic AST Facts:

• Most storage tanks contain
  petroleum products.

• State AST regulations may be
  more stringent than Federal
  requirements.

• A spill of only one gallon of
  oil can contaminate a million
  gallons of water.

• ASTs should have a
  secondary containment area
  to contain spills.

• If a tank is not used for more
  than a year it is  possible
  your State may require you to
  declare it as "Out of
  Service".

• Inspect any accumulated
  water for chemicals prior to
  discharge from the AST area.

• Most States require AST
  inspections by Fire
  Marshalls.
    Above ground storage tanks (ASTs) are tanks or other containers that are above ground, partially
    buried, bunkered, or in a subterranean vault. These can include floating fuel systems. This fact
    sheet focuses on the management of facilities with ASTs to prevent contamination of drinking
    water sources (ground water and surface water used as public drinking water supplies).
   Above Ground Storage Tank Use
   The majority of storage tanks contain petroleum
   products (e.g., motor fuels, petroleum solvents,
   heating oil, lubricants, used oil). Oil storage
   facilities with ASTs are typically found in mar-
   keting terminals, refineries, and fuel distribution
   centers. Storage tanks may also be found in
   airports, school bus barns, hospitals, automotive
   repair shops, military bases, farms, and indus-
   trial plants. Discharges of chemicals, petroleum,
   or non-petroleum oils from storage tanks can
   contaminate source water. Product spilled,
   leaked, or lost from storage tanks may accumu-
   late in soils or be carried away in storm runoff.
1 - Above Ground Storage Tank
   Some of the causes for storage tank releases are holes from corrosion, failure of piping systems, and spills
   and overfills, as well as equipment failure and human operational error. The Spill Prevention Control and
   Countermeasures (SPCQ regulations require owners or operators of certain above ground oil storage
   facilities to prepare and comply with written, site-specific, spill prevention plans (see 40 CFR Part 112):
             •  Facilities with a total above ground oil storage capacity of more than 1,320 gallons;

             •  Single above ground tanks with an oil storage capacity of more than 660 gallons; and

             •  Facilities with a combined underground oil storage capacity greater than 42,000 gallons.
    Please note, however, that State AST regulations may be more stringent or differ in other ways from the
    Federal requirements. You must check with local regulatory authorities to make sure which ASTs are
    subject to what requirements. All AST facility owners or operators exempt from these regulations
    should still consider implementing the prevention measures described in this fact sheet to preclude fu-
    ture storage tank problems.

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PAGE
                                                             SOURCE WATER PROTECTION PRACTICES BULLETIN
      Why is  it Important to  Manage  Above Ground Storage Tanks
                              Near Sources  of Drinking Water?
      Storage tank releases can contaminate
      soil and drinking water supplies.
      Petroleum products are composed of
      volatile organic compounds (VOCs).
      Any oil spill can pose a serious threat
      to human health and the environment,
2 -
Oil in
water.
                                  requires remediation that extends be-
                                  yond your facility's boundary, and
                                  results in substantial cleanup costs.
                                  Even a small spill can have a serious
                                  impact. A single pint of oil released
                                  into the water can cover one acre of
                                  water surface area and can seriously
                                  damage an aquatic habitat. A spill of
                                  only one gallon of oil can contaminate
                                  a million gallons of water. It may take
                                  years for an ecosystem to recover
                                  from the damage caused by an oil spill.
The location of the facility must be
considered in relation to drinking
water wells, streams, ponds and
ditches (perennial or intermittent),
storm  or sanitary sewers, wetlands,
mudflats, sandflats, farm drain tiles, or
other navigable waters. Factors such
as the  distance to drinking water wells
and surface water, volume of material
stored, worse case weather conditions,
drainage patterns, land contours, and
soil conditions must also be taken  into
account.
         Available  Prevention  Measures  to Address Above Ground
                                             Storage Tanks
The following list of prevention measures
is not all-encompassing; others can be
found in the references provided at the end
of the document. Furthermore, detailed
explanations of each device mentioned
below are found in the supporting docu-
ments. Please keep in mind that individual
prevention measures may or may not be
adequate to prevent contamination of
source waters. Most likely, individual
Federal  AST Requirements under 40  CFR Part 112
                                       A SINGLE PINT OF OIL
                                  RELEASED INTO THE WATER CAN
                                     COVER 1 ACRE OF WATER
                                  SURFACE AREA AND SERIOUSLY
                                   DAMAGE AQUATIC HABITATS.
 measures should be combined in an overall
 prevention approach that considers the
 nature of the potential source of contami-
 nation, the purpose, cost, operational, and
 maintenance requirements of the measures,
 the vulnerability of the source water, the
 public's acceptance of the measures, and
 the community's desired degree of
 risk reduction.
Follow standard tank filling practices when
filling tanks to prevent spills and overfills.
Furthermore, all ASTs should have a sec-
ondary containment area that contains
spills and allows leaks to be more easily
detected. The containment area surround-
ing the tank should hold 110 percent of the
contents of the largest tank plus freeboard
for precipitation. Secondary containment
for ASTs must be impermeable to the ma-
terials being stored. Methods include
berms, dikes, liners, vaults, and double-
walled tanks. A manually controlled sump
pump should be used to collect rain water
that may accumulate in the secondary con-
tainment area. Any discharge should be
inspected for petroleum or chemicals prior
to being dispensed.
                                 Routinely monitor ASTs to ensure they
                                 are not leaking. An audit of a newly
                                 installed tank system by a professional
                                 engineer can identify and correct problems
                                 such as loose fittings, poor welding, and
                                 poorly fit gaskets. After installation, inspect
                                 the tank system periodically to ensure it is
                                 in good condition. Depending on the
                                 permeability of the secondary containment
                                 area, more frequent containment area
                                 checks may be necessary. Areas to inspect
                                 include tank foundations, connections,
                                 coatings, tank walls, and the piping system.
                                 Integrity testing should be done
                                 periodically by a qualified professional and
                                 in accordance to applicable standards.

                                 If an AST has remained out of service for
                                 more a year or more, many States require
   owners to maintain and monitor the tank,
   declare the tank inactive, or remove it. If
   the tank is declared inactive, remove all
   substances from the AST system (including
   pipes) and completely clean the inside.
   Secure tanks by bolting and locking all
   valves, as well as capping all gauge open-
   ings and fill lines. Clearly label tanks with
   the date and the words "Out of Service."
   Samples may be required when removing
   tanks to determine if any contamination
   has occurred. Most States require out-of-
   service tanks to be inspected and meet leak
   detection requirements before they are put
   back into service.

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     Additional AST Prevention Measures
The following prevention measures go beyond the Federal regulations under 40 CFR Part 112, but are highly recommended:
Facility Location:
The location of the facility
must be considered in rela-
tion to drinking water wells,
streams, ponds and ditches
(perennial or intermittent),
storm or sanitary sewers,
wetlands, mudflats, sandflats,
farm drain tiles, or other
navigable waters. The dis-
tance to drinking water wells
and surface water, volume of
material stored, worse case
weather conditions, drainage
patterns, land contours, and
soil conditions  must also be
taken into account.
    Inferential Space
    (Monitored for Vacuum,
    Pressure. Vapor, or Liquid)
Coating to Provide
Corrosion Protection for
External Wall
4 - Cross section of a double-walled tank.
         5 - Tanks in a vault.
Corrosion Control:
ASTs should have corro-
sion protection for the
tank. Options include
elevating tanks, resting
tanks on continuous con-
crete slabs, installing dou-
ble-walled tanks, cathodi-
cally protecting the tanks,
internally lining tanks,
inspecting tanks accord-
ing to American Petro-
leum Institute standard,
or a combination  of the
options listed above. All
underground piping to
                                       the tank should be double
                                       -walled or located above
                                       ground or cathodically
                                       protected so you can
                                       inspect it when it fails.
                                       To maximize system
                                       safety, seal the floors,
                                       containment area, and
                                       sump pump pit with an
                                       appropriate coating (e.g.,
                                       petroleum resistant coat-
                                       ing). Any accumulated
                                       water should be inspected
                                       for petroleum or chemi-
                                       cals prior to discharge.
                                                                Periodic Cleanup:
                                                                Accumulated minor spillage, over
                                                                time, may result in a film or sheen
                                                                on collected rain water, making it
                                                                unsuitable for discharge to the soil
                                                                or drains. Periodic cleanup of the
                                                                containment areas (e.g., sweeping
                                                                with a broom  and using limited
                                                                absorbent) can prevent unnecessary
                                                                dirt and contaminant buildup.
                                                                         A ROOF COVERING
                                                                         A 10,000 GALLON
                                                                            TANK WILL
                                                                          CONSERVE 600-
                                                                         1,000 GALLONS OF
                                                                           GASOLINE PER
                                                                           YEAR, WHICH
                                                                           WOULD HAVE
                                                                            ESCAPED BY
                                                                           EVAPORATION.
                  7 - Covered
                  AST with
                  secondary
                  containment
                  (above)
                  8 - Elevated
                  AST (left)
       Preventing  Evaporation:
       While not a preventative measure
       for source water protection, pre-
       venting evaporation has economic
       and air quality benefits. To keep
       out rain and reduce evaporation
       losses and moisture condensation,
       paint tanks a reflective color, install
       them in an east-west direction,
       install a low-pressure valve on top
       of the tank, and cover the struc-
       ture. A roof structure covering a
       10,000 gallon tank will conserve
       600 to 1,000 gallons of gasoline per
       year, which would have escaped by
       evaporation without the shade
       cover.
                                                                   Registration Programs:
                                                                   Local jurisdictions may want to implement registration
                                                                   programs for exempt tanks, in order to exercise some
                                                                   oversight of their construction and operation. Furthermore,
                                                                   most States also require inspections for ASTs by fire
                                                                   marshals. Inspection programs can be expanded to cover
                                                                   water contamination issues.
                                            6 - Floating fuel station in the Amazon.

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    PAGE 4
                                                         SOURCE WATER PROTECTION PRACTICES  BULLETIN
                                 Additional Information
The following documents contain more detailed information on ASTs and are available for free on the Internet. You can
contact your EPA Regional SPCC or Oil Coordinator for more information, as well. There are also State and local
authorities that are often located in Oil, Environmental, or Pollution Control Divisions who can provide you with local
regulations for ASTs.
Contact local government authorities in your area to see if there are ordinances in place to manage ASTs. Numerous
examples of local source water protection-related ordinances for various potential contaminant sources can be found at:
http://www.epa.gOv/r5water/ordcom/http://www.epa.gov/owow/nps/ordinance/http://www.epa.gov/owow/nps/
ordinance /links .htm

The following documents provide additional information on AST prevention measures and regulations:
                                                               breather valve
                                                                               spray nozzle
                                                                                   manhole

                                                        automatic tank gauge
                                                          secondary Inlet
                                                 bund wal
                                          9 - AST diagram.
                                                                      fixed-roof tank
Florida Cooperative Extension Service, In-
stitute of Food and Agricultural Sciences,
University of Florida.. Above-Ground Fuel
Storage Systems (EES-61). (1992, October).
Retrieved February 9, 2001 from the World
Wide Web: http://www.cdc.gov/niosh/
nasd/docs2/as 04300.html
Minnesota Pollution Control Agency. Above
-Ground Storage Tank Systems. (2000,
OctoberlS). Retrieved February 9, 2001
from the World Wide Web:
http://www.pca.state.mn.us/cleanup/
ast.html
Minnesota Pollution Control Agency.
Out-of-Service Tank Systems. (1998,
November). Retrieved February 9, 2001
from the World Wide Web:
http://www.pca.state.mn.us/cleanup/ast.html
Purdue University Extension Service. Petroleum Product Storage Practices on the Farm. (1991). Retrieved February 12,
2001 from the World Wide Web: http://pasture.ecn.purdue.edu/~epados/farmstead/fuel/src/title.htm
South Dakota Department of Environment and Natural Resources, Ground Water Quality Program.. Frequently Asked
Questions about UST and AST Systems, (n.d.). Retrieved February 19, 2001 from the World Wide Web: http://
www.state.sd.us/denr/DES/Ground/tanks/FAQTANK.htm
U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response. SPCC Requirements and
Pollution Prevention Practices for Bulk Storage Facilities, (n.d.). Retrieved February 9, 2001 from the World Wide Web:
http://www.epa.gov/oilspill/spcc/index.htm
U.S. Environmental Protection Agency, Office of Water. Storm Water Management for Industrial Activities —
Developing Pollution Prevention Plans and Best Management Practices. Section 3.6 - Liquid Storage in Above-Ground
Storage Tanks (EPA 832/R-92-006). (1992,September). Retrieved February 9, 2001 from the World Wide Web:
http://www.epa.gov/owm/sw/indguide/index.htm
U.S. Environmental Protection Agency, Oil Spill Program. Introduction and Background to the Oil Pollution Prevention
Regulation, (n.d.). Retrieved May 1, 2001 from the World Wide Web: http://www.epa.gov/oilspill/spcc/index.html

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                                          Image  Credits
 1 - Federal Facilities Environmental Stewardship and Compliance Assistance Center. Assistance: Facility Regulatory Tour
 for Storage Tanks: Above Ground Storage Tanks. Accessed on July 26, 2010 at:
 http://www.fedcenter.gov/assistance/facilitytour/tanks/aboveground/

 2 - Flickr Creative Commons: Attribution only search. Psychedelic water uploaded by "notsogoodphotography" on April
 24, 2010. http://www.flickr.com/photos/notsogoodphotography/4547807568/

 3 - Flickr Creative Commons: Attribution only search. Imperium storage tanks, uploaded by "skidrd" on  August 18,
 2007. http://www.flickr.com/photos/skidrd/1160891313/
                                       + stairs
          m
          floatin
10 - AST Diagram.
                         floating-roof tank
                          4, 5,11 - EPA: Office of Solid Waste and
                          Emergency Response, September 2005. RCRA
                          Training Module: Introduction to Tanks (40
                          CFR Parts 264/265, Subpart J)
                          http://www.epa.gov/epawaste/inforesources/
                          pubs /hotline /training/tanks 05.pdf

                          6 - TravelPod Blogs. Amazon floating fuel
                          stations, uploaded by "Suenson_taylors" on
                          November 7, 2009.
                          http://www.travelpod.com/travel-photo/
                          suenson_taylors/l/1257735331/amazon-
                          floating-fuel-stations, jpg/ tpod.html

                          7, 8 - From original AST document.

                          9, 10 - Merriam-Webster Visual Dictionary
 Online. Search for - Energy :: Geothermal and Fossil Energy :: Oil :: Tanks [1] and [3]. Diagrams of ASTs.
 http://visual.merriam-webster.com/energy/geothermal-fossil-energy/oil/tanks_l.php
 Back Cover - Flickr Creative Com-
 mons: Attribution only search. Oil/
 water storage tanks, Conroe oil field,
 uploaded by "roy.luck" on May 10,
 2009.
                 11 - AST diagram.
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                     Source Water Protection Practices Bulletin


                Managing Above Ground Storage Tanks to Prevent
                          Contamination of Drinking Water


                          The mission of EPA is to protect human health
                          and to safeguard the natural environment — air,
                            water and land — upon which life depends.


                            USEPA East (EPA East) [Old ICC Building]
                                 1201 Constitution Avenue N.W.
                                    Washington, DC 20004
                                          United States
                                          Environmental Protection
                                          Agency
Office of Water (4606)
EPA ### ### ### ###
www. epa.gov/safewater
August 2010

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