RECOMMENDED GUIDELINES
FOR TANK CLOSURES
AND CHANGE-IN-SERVICE
Revised February 2013
Check with the Oklahoma Corporation
Commission (OCC), (405) 521-4683, to determine
if tank location has been registered per
regulations. If tanks are not registered,
complete the Registration Form 7530-1 showing
proper owner name, address, number of tanks,
and tank sizes to register site with the Petroleum
Storage Tank program. If tanks are registered,
but ownership has changed, complete the PSTD
Change of Ownership form. All forms must be
submitted by mail or in person with original
signatures, no fax or email copies can be
accepted.
SCHEDULE
Notification of AST or UST closure for piping
and/or tanks is required by submitting the PSTD
Scheduling Form providing the names of OCC
licensed Remover and Environmental Consultant
a minimum of 14 days prior to the removal date.
Local Fire Department and Code Enforcement
Officials should also be notified.
The PST Division may schedule a Commission
Employee to be present during sampling.
Contact the PST Division (405) 521-4683 not less
than two (2) working days prior to scheduled
work date if a change in scheduling is required.
EQUIPMENT
The licensed remover and/or consultant should
have materials, labor, and equipment on site to
comply with the requirements of EPA, OCC, DEQ
and Local safety rules and/or fire codes during
closure operations and to meet the testing
protocol for required samples.
REMOVAL
An OCC licensed remover must be onsite at all
times beginning with break out of concrete.
Permanent tank closures must be performed by
removing the tanks and all associated lines
unless the OCC has preapproved a variance to fill
the tank in place with concrete slurry. Product
piping should be drained into the tanks, flushed
and disconnected. Remove all liquids and
residue using explosion proof equipment.
Proper disposal of all fluids documented with a
waste manifest should be submitted with the
tank closure report form.
Excavate to the top of the tank and remove all
tank appurtenances, leaving the vent piping in
place until the tank is properly purged or inerted.
Additional Tank Removal Guidance, Checklist and
forms can be found on the OCC website,
www.occeweb.com, PST Division, Forms and
Guidance, Compliance.
Once removed from the excavation, use caution
to never drag or roll a tank. Tanks must be
properly labeled prior to transport. All openings
should be plugged leaving one 1/8-inch vent.
Backfill should be stockpiled onsite on
impermeable plastic, covered and bermed if rain
is possible within 48 hours.
SAMPLING
Laboratory samples shall be analyzed by a
Department of Environmental Quality certified
laboratory and tested for Benzene, Toluene,
Ethylbenzene, Xylene (BTEX) and Total
Petroleum Hydrocarbons (TPH). Analyses of soil
and/or groundwater should be conducted in
accordance with the type of product previously
stored. If product is unknown, both gasoline and
diesel range TPH should be analyzed.
Use either the AST or UST Soil Sample Location
Policy also available on the website.
For USTs and ASTs, one sample is required in
native soils beneath each tank, the down
gradient wall or outside down gradient
containment, and every 20 feet beneath steel or
fiberglass product piping, or every 40 feet
beneath flex piping. Aboveground piping should
be sampled in areas of visual staining. If
groundwater is present or recharges into the
tank pit, a sample should be collected for
analysis.
Samples shall be properly prepared for
shipment, cooled to 4°C and a chain-of-custody
record maintained throughout sampling.
Samples shall be transported or delivered to the
laboratory within 24 hours and analyzed within
appropriate holding times. The person collecting
the samples must be under supervision of or be a
licensed Environmental Consultant. If the
consultant can’t be onsite, a site-specific
discussion of sample location selection must be
conducted prior to removal. Consultant should
be available for any further discussion during
removal activities.
One composite backfill sample should be
collected for every 50 cubic yards. Coordinate
disposal or reuse of backfill with the hydrologist
in the PST Technical Department. If existing
tanks are being removed and replaced in the
same tank pit, clean backfill must be used. Soil,
backfill and water to be transported off site shall
be previously coordinated with the Department
of Environmental Quality if required.
REUSE – STORAGE
Tanks must be recertified by the original
manufacturer prior to reuse. Tanks that
previously contained gasoline or diesel may not
be used for drainage culverts or subsequent
storage of foods or liquids intended for animal or
human consumption. A certificate of destruction
or bill of sale must include a statement
concerning future use of tanks (destruction,
salvage).
CLOSURE-IN-PLACE
Removal of tanks is preferred. Closure-in-place
may be considered when due to tank location
adjacent structures may be damaged. A variance
request must be submitted and approved by an
OCC Administrative Law Judge prior to closure in
place. Samples shall be collected in accordance
with the AST or UST Soil Sample Location Policy.
All piping must be removed or may be capped if
not accessible.
Tanks shall be uncovered, all residue removed,
and holes cut in top of tank if existing openings
are not adequate to completely fill the tank.
Concrete slurry must be used, and the material
receipt submitted with the closure report that
documents volume pumped was adequate to fill
tank(s). All tank openings should be covered,
plugged, or capped, and the excavation
backfilled.
REPORT
The closure report describing all site activity and
observations is due within 45 days of sampling
and removal. Use of the OCC AST or UST Closure
Report Form is required. The list of required
documents to be included in the report is found
on the form and must be submitted.
Include a sketch of the site showing the location
of tanks prior to removal or closure-in-place.
This sketch should include piping layout,
dimensions, north arrow, buildings, roads and
streets, UST locations and other data to locate
the closed UST facilities. This sketch should also
show the sampling points and sample
name/designation. File an amended UST
registration form for the removed, closed-inplace, or newly installed tanks with proper
identification and information. Do not repeat
tank numbers between new and closed/removed
tank(s).
GUIDELINES FOR
AST and UST STORAGE
TANK CLOSURE
Include in the report a copy of the laboratory
analysis (BTEX and TPH) of all sampling and
testing done concerning the site during the tank
closure. Attach labeled photographs that
document tank pit location, dispenser location
and materials of construction for tanks and
piping removed.
Provide information concerning future use of
tanks (i.e., destruction, use in another capacity,
etc.) This paragraph does not apply if tanks are
not removed. Provide information pertaining to
the backfill material (was it removed from the
site or returned to the excavation pit). Provide
statement about pit water if present or if water
was removed from the site. Attach copies of all
manifests for backfill, liquids evacuated from the
tank, or tank pit water.
CHANGE-IN-SERVICE
To change the use of an aboveground or
underground tank from storing a regulated
substance to a non-regulated substance, the
tanks must emptied and cleaned. A site
assessment is required. Follow the steps as
outlined for Closure-in-Place.
OKLAHOMA
CORPORATION COMMISSION
Petroleum Storage Tank Division
UST/AST PROGRAM OFFICE
405-521-4683