DAQ-2024-010877

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DAQC-1009-24
Site ID 10122 (B1)

MEMORANDUM

TO: FILE – BIG WEST OIL

THROUGH: Harold Burge, Major Source Compliance Manager

FROM: Jeremiah R. Marsigli

DATE: October 3, 2024

SUBJECT: Partial Compliance Evaluation (#1 of 4 Tanks), Major, Davis County,
FRS ID# UT0000004901100008

INSPECTION DATE: September 12, 2024

SOURCE ADDRESS: 333 West Center Street, North Salt Lake, Utah

MAILING ADDRESS: 333 West Center Street, North Salt Lake, Utah 84054

SOURCE CONTACTS: E. Faithe Schwartzengraber, Environmental Manager, [phone]
Ian Muller, Environmental Engineer, [phone]
Brady Miller, Environmental Engineer, [phone]

OPERATING STATUS: Operating normally

PROCESS DESCRIPTION: Petroleum refinery processing 30,000 bbls/day of crude. Big West Oil
refinery’s capacity is 30,000 bbls/day. Units include crude heater, crude
pre-flash heater, unifiner heater, reformer, boilers, MSCC and alky
heaters, 2 flares, MIDW furnace, SRU, and HDS.

This inspection was conducted on the storage tanks. There are 20 fixed
roof (cone) tanks, 14 internal floating roof tanks plus Tank 20 after
retrofit, and 11 external floating roof tanks. All external floating roof
tanks are pontoon type, with welded construction and rim mounted
secondary seals. All EFRTs have mechanical shoe primary seals. Internal
floating roof tanks are equipped with either vapor mounted, liquid
mounted, or mechanical shoe seals.

APPLICABLE
REGULATIONS: Approval Order DAQE-AN101220080-80, dated May 3, 2023
UAC, R307-327, Petroleum Liquid Storage
40 CFR 60, Subpar K, Ka, and Kb
40 CFR 63, Subpart CC (incorporated into UACR and evaluated in that
section)

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SOURCE INSPECTION
EVALUATION:

SECTION I: GENERAL PROVISIONS

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101] Status: This is not an inspection item. I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401] Status: In compliance. No limit exceedances were found. I.3 Modifications to the equipment or processes approved by this AO that could affect the emissions covered by this AO must be reviewed and approved. [R307-401-1] Status: In compliance. No unapproved modifications were discovered. I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records shall be kept for a minimum of five (5) years. [R307-401] [R307-415-6b] Status: In compliance. All records requested during this inspection have been provided. I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall, to the extent practicable, maintain and operate any equipment approved under this Approval Order including associated air pollution control equipment in a manner consistent with good air pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available to the Director which may include, but is not limited to, monitoring results, opacity observations, review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4] Status: In compliance. The source appeared to be well maintained. A preventative and as needed maintenance system is in place. I.6 The owner/operator shall comply with R307-150 Series. Inventories, Testing and Monitoring. [R307-150] Status: In compliance. Inventories have been submitted as requested. Testing and monitoring requirements are described in specific Approval Order conditions. I.7 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns. [R307-107] Status: In compliance. Breakdowns are reported when necessary.

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I.8 The owner/operator shall submit documentation of the status of construction of Tank 20 to the Director within 18 months from the date of this AO. This AO may become invalid if
construction is not commenced within 18 months from the date of this AO or if construction is
discontinued for 18 months or more. To ensure proper credit when notifying the Director, send the documentation to the Director, attn.: NSR Section. [R307-401-18]

Status: In compliance. Tank 20 has not been retrofitted yet. The company is aware the 18 month deadline is November 3, 2024.

SECTION II: PERMITTED EQUIPMENT
II.A THE APPROVED EQUIPMENT II.A.1 Big West Oil Refinery Tank Farm II.A.2 Tank 3 Crude Oil Storage - 80,000 bbl with external floating roof II.A.3 Tank 9 Wastewater Equalization - 20,000 bbl with internal floating roof II.A.4 Tank 19 Petroleum Liquid Storage - 20,000 bbl with vertical fixed roof II.A.5 Tank 20 Gasoline Storage - 30,000 bbl with internal floating roof (new) II.A.6 Tank 21 Distillate Fuel Oil Storage - 60,000 bbl with vertical fixed roof II.A.7 Tank 22 Distillate Fuel Oil Storage - 60,000 bbl with vertical fixed roof II.A.8 Tank 23 Distillate Fuel Oil Storage - 20,000 bbl with vertical fixed roof II.A.9 Tank 24 Distillate Fuel Oil Storage - 20,000 bbl with vertical fixed roof II.A.10 Tank 25 Distillate Fuel Oil Storage - 40,000 bbl with vertical fixed roof II.A.11 Tank 28 Light Crude Storage - 80,000 bbl with external floating roof II.A.12 Tank 29 Gasoline Storage - 40,000 bbl with internal floating roof II.A.13 Tank 34 Sour Water Storage - 15,000 bbl with fixed roof II.A.14 Tank 45 Petroleum Liquid Storage - 40,000 bbl with internal floating roof II.A.15 Tank 50 Petroleum Liquid Storage - 30,000 bbl with internal floating roof
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II.A.16 Tank 56 Petroleum Liquid Storage - 7,250 bbl with internal floating roof

II.A.17 Tank 87 Ethanol Storage - 7,250 bbl with internal floating roof with mechanical shoe

II.A.18 Tank 90 Wastewater Equalization - 20,000 bbl with internal floating roof

II.A.19 Tank 95 Alkylate Storage - 30,000 bbl with internal floating roof

II.A.20 Tank A2 Fresh Caustic Storage - 4,500 bbl
(listed for informational purposes only)

II.A.21 Tank B2
Spent Caustic Storage - 1,450 bbl
(listed for informational purposes only)

Status: No unapproved equipment was observed. There are several grandfathered tanks due to
construction date as follows:

External floating roof tanks (tank number and year constructed):
5 (1950)
43 (1973)
51 (1957)
52 (1957)
53 (1952)
54 (1970)
59 (1958)
62 (1961)
72 (1961)

Internal floating roof tanks (tank number and year constructed):

4 (1973)
6 (1970)
35 (1960)
42 (1950)
44 (1981)
65 (1960)
75 (1970)
Cone roof, no floater: 31 replacement in kind, contains finished diesel. These tanks are subject to the requirements of 40 CFR 63, Subpart CC (or more stringent requirements), which is incorporated into UAC R307-327.

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SECTION II: SPECIAL PROVISIONS II.B REQUIREMENTS AND LIMITATIONS II.B.1 Volatile Organic Compound (VOC) and Hazardous Air Pollutants (HAPs) Limitations II.B.1.a The facility shall abide by all applicable requirements in the most current version of R307-325 through R307-341 for VOC sources located in Ozone Nonattainment and Maintenance Areas. At a minimum, Reasonable Available Control Technology (RACT) control measures are required and Best Available Control Technology (BACT) will be no less stringent than RACT. [R307-325] Status: This is not an inspection item. Utah Division of Air Quality’s engineering section reviews RACT and BACT requirements for incorporation into Approval Orders during the New Source Review process. II.B.1.b The combined VOC emissions from tanks listed in this AO shall not exceed 46.85 tons per rolling 12-month period. The VOCs emitted to the atmosphere shall be calculated using EPA approved methodologies on a monthly basis. Compliance with the limitation shall be determined on a rolling 12-month total. No later than 20 days after the end of each month, a new 12-month total shall be calculated using data from the previous 12 months. [R307-401-8(1)(a)] Status: In compliance. VOC emissions were calculated as 17.89 tons through July 31, 2024.

R307-327-4. General Requirements.
(1) Any existing stationary storage tank, reservoir or other container with a capacity greater than 40,000
gallons (150,000 liters) that is used to store volatile petroleum liquids with a true vapor pressure greater
than 10.5 kilo pascals (kPa) (1.52 psia) at storage temperature shall be fitted with control equipment that
will minimize vapor loss to the atmosphere. Storage tanks, except those erected before January 1, 1979,
which are equipped with external floating roofs, shall be fitted with an internal floating roof that shall
rest on the surface of the liquid contents and shall be equipped with a closure seal or seals to close the
space between the roof edge and the tank wall, or alternative equivalent controls, provided the design
and effectiveness of such equipment is documented and submitted to and approved by the director. The
owner or operator shall maintain a record of the type and maximum true vapor pressure of stored liquid.
Status: In compliance. All required tanks have internal floating, external floating, or fixed
roofs. The company does not use any equivalent methods.
(2) The owner or operator of a petroleum liquid storage tank not subject to (1) above, but containing a
petroleum liquid with a true vapor pressure greater than 7.0 kPa (1.0 psia), shall maintain records of the
average monthly storage temperature, the type of liquid, throughput quantities, and the maximum true
vapor pressure.
Status: In compliance. All required tanks have internal floating, external floating, or fixed
roofs. The company does not use any equivalent methods.
R307-327-5. Installation and Maintenance.

(1) The owner or operator shall ensure that all control equipment on storage vessels is properly installed
and maintained.

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(a) There shall be no visible holes, tears or other openings in any seal or seal fabric and all openings,
except stub drains, shall be equipped with covers, lids, or seals.
(b) All openings in floating roof tanks, except for automatic bleeder vents, rim space vents, and leg
sleeves, shall provide a projection below the liquid surface.
(c) The openings shall be equipped with a cover, seal, or lid.
(d) The cover, seal, or lid is to be in a closed position at all times except when the device is in actual use.
(e) Automatic bleeder vents shall be closed at all times except when the roof is floated off or landed on
the roof leg supports. Rim vents shall be set to open when the roof is being floated off the leg supports or
at the manufacturer's recommended setting.
(f) Any emergency roof drain shall be provided with a slotted membrane fabric cover or equivalent cover
that covers at least 90 percent of the area of the opening.
(2) The owner or operator shall conduct routine inspections from the top of the tank for external floating
roofs or through roof hatches for internal floating roofs at six month or shorter intervals to insure there
are no holes, tears, or other openings in the seal or seal fabric.
(a) The cover must be uniformly floating on or above the liquid and there must be no visible defects in
the surface of the cover or petroleum liquid accumulated on the cover.
(b) The seal(s) must be intact and uniformly in place around the circumference of the cover between the
cover and tank wall.
(3) A close visible inspection of the primary seal of an external floating roof is to be conducted at least
once per year from the roof top unless such inspection requires detaching the secondary seal, which
would result in damage to the seal system.
(4) Whenever a tank is emptied and degassed for maintenance, an emergency, or any other similar
purpose, a close visible inspection of the cover and seals shall be made.
(5) The director must be notified 7 days prior to the refilling of a tank that has been emptied, degassed
for maintenance, an emergency, or any other similar purpose. Any non-compliance with this rule must
be corrected before the tank is refilled.
Status: In compliance. The secondary seals are inspected semi-annually and the primary seals
are inspected annually. All inspections are documented. Refilling notifications have
been submitted

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R307-327-6. Retrofits for Floating Roof Tanks.

(a) The tank is a welded tank, the true vapor pressure of the contained liquid is 27.6 kPa (4.0 psia) or
greater and the primary seal is one of the following:

(i) A metallic type shoe seal, a liquid-mounted foam seal, a liquid-mounted liquid-filled seal, or
(ii) Any other primary seals that can be demonstrated equivalent to the above primary seals.
(b) The tank is a riveted tank, the true vapor pressure of the contained liquid is 10.5 kPa (1.5 psia) or
greater, and the primary seal is as described in (a) above.
(c) The tank is a welded or riveted tank, the true vapor pressure of the contained liquid is 10.5 kPa (1.5
psia) or greater and the primary seal is vapor-mounted. When such primary seal closure device can be
demonstrated equivalent to the primary seals described in (a) above, these processes apply.
(2) The owner or operator of a storage tank subject to this rule shall ensure that all the seal closure
devices meet the following requirements:
(a) There shall be no visible holes, tears, or other openings in the seals or seal fabric.
(b) The seals must be intact and uniformly in place around the circumference of the floating roof
between the floating roof and the tank wall.
(c) For vapor mounted primary seals, the accumulated area of gaps between the secondary seal and the
tank wall shall not exceed 21.2 cm2 per meter of tank diameter (1.0 in2 per ft. of tank diameter) and the
width of any gap shall not exceed 1.27 cm (1/2 in.). The owner or operator shall measure the secondary
seal gap annually and make a record of the measurement.
(3) The following are specifically exempted from the requirements of (1) above:
(a) External floating roof tanks having capacities less than 10,000 barrels (420,000 gals) used to store
produced crude oil and condensate prior to custody transfer.
(b) A metallic type shoe seal in a welded tank that has a secondary seal from the top of the shoe seal to
the tank wall (a shoe mounted secondary seal).
(c) External floating roof tanks storing waxy, heavy pour crudes.
(d) External floating roof tanks with a closure seal device or other devices installed that will control
volatile organic compounds (VOC) emissions with an effectiveness equal to or greater than the seals
required in (1) above. It shall be the responsibility of the owner or operator of the source to demonstrate
the effectiveness of the alternative seals or devices to the director. No exemption under (3) shall be
granted until the alternative seals or devices are approved by the director.
Status: In compliance. The refinery has installed seals to all external tanks. The seals are of
the correct types and all checks are done and recorded as required.
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R307-327-7. Alternate Methods of Control.

(1) Any person may apply to the director for approval of an alternate test method, an alternate method of
control, an alternate compliance period, an alternate emission limit, or an alternate monitoring schedule.
The application must include a demonstration that the proposed alternate produces an equal or greater air
quality benefit than that required by R307-327, or that the alternate test method is equivalent to that
required by these rules. The director shall obtain concurrence from EPA when approving an alternate test
method, an alternate method of control, an alternate compliance period, an alternate emission limit, or an
alternate monitoring schedule.

(2) Manufacturer's operational specifications, records, and testings of any control system shall use the
applicable EPA Reference Methods of 40 CFR Part 60, the most recent EPA test methods, or EPA-
approved state methods, to determine the efficiency of the control device. In addition, the owner or
operator must meet the applicable requirements of record keeping for any control device. A record of all
tests, monitoring, and inspections required by R307-327 shall be maintained by the owner or operator for
a minimum of 2 years and shall be made available to the director or the director's representative upon
request. Any malfunctioning control device shall be repaired within 15 calendar days after it is found by
the owner or operator to be malfunctioning, unless otherwise approved by the director.
(3) For purposes of determining compliance with emission limits, VOCs and nitrogen oxides will be
measured by the test methods identified in federal regulation or approved by the director. Where such a
method also inadvertently measures compounds with negligible photochemical reactivity, an owner or
operator may exclude these negligibly reactive compounds when determining compliance with an
emissions standard.
Status: Not applicable. No alternative methods of control are utilized.

R307-327-8. Compliance Schedule.

All sources within any newly designated nonattainment area for ozone shall be in compliance with this
rule within 180 days of the effective date of designation to nonattainment.

Status: In compliance. See above for specific details.

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Subpart K-Standards of Performance for Storage Vessels for Petroleum Liquids for Which
Construction, Reconstruction, or Modification Commenced After June 11, 1973, and Prior to May
19, 1978

§ 60.110 Applicability and designation of affected facility.

(a) Except as provided in § 60.110(b), the affected facility to which this subpart applies is each storage
vessel for petroleum liquids, which has a storage capacity greater than 151,412 liters (40,000 gallons).
(b) This subpart does not apply to storage vessels for petroleum or condensate stored, processed, and/or
treated at a drilling and production facility prior to custody transfer.
(c) Subject to the requirements of this subpart is any facility under paragraph (a) of this section which:
(1) Has a capacity greater than 151, 416 liters (40,000 gallons), but not exceeding 246,052 liters (65,000
gallons), and commences construction or modification after March 8, 1974, and prior to May 19, 1978.
(2) Has a capacity greater than 246,052 liters (65,000 gallons) and commences construction or
modification after June 11, 1973, and prior to May 19, 1978.

Status: In compliance. Three tanks have been identified as applicable to the requirements of
Subpart K, based on the date of installation. These tanks are as follows:

Tank Size Year Built Vapor Pressure Control Device
Tank 3 3,360,00 gal. 1948* Wax Crude (0.1 psi) Ext Float
Tank 4 1,073,100 1973 Gasoline Internal Float
Tank 43 3,360,000 gal. 1973 Light Crude (>1.5 psi). Ext Float

* It should be noted that Tank 3 has been considered by Big West Oil to be subject to
Subpart K for historical reasons that may include storage of products that would have
triggered Subpart K applicability. Tank 3 has also been fitted with Subpart Kb
fittings (gasketed covers on all openings, column sleeves, etc).

§ 60.112 Standard for volatile organic compounds (VOC).

(a) The owner or operator of any storage vessel to which this subpart applies shall store
petroleum liquids as follows:
(1) If the true vapor pressure of the petroleum liquid, as stored, is equal to or greater than
78 mm Hg (1.5 psi) but not greater than 570 mm Hg (11.1 psi), the storage vessel shall be
equipped with a floating roof, a vapor recovery system, or their equivalents.
(2) If the true vapor pressure of the petroleum liquid as stored is greater than 570 mm Hg
(11.1 psi), the storage vessel shall be equipped with a vapor recovery system or its
equivalent.

Status: In compliance. Only Tank 43 contains material that has a vapor pressure > 1.5 psi >
11.1 psi. This tank is equipped with an external floating roof, mechanical shoe
primary seal, and rim mounted secondary seal system. Tank 3 is also an external
floating roof tank with mechanical shoe primary seal and rim mounted secondary seal
but stores product below 1.5 psi.

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§ 60.113 Monitoring of operations.

(a) Except as provided in paragraph (d) of this section, the owner or operator subject to this
subpart shall maintain a record of the petroleum liquid stored, the period of storage, and the
maximum true vapor pressure of that liquid during the respective storage period.
(b) Available data on the typical Reid vapor pressure and the maximum expected storage
temperature of the stored product may be used to determine the maximum true vapor
pressure from nomographs contained in API Bulletin 2517, unless the Administrator
specifically requests that the liquid be sampled, the actual storage temperature determined,
and the Reid vapor pressure determined from the sample(s).
(c) The true vapor pressure of each type of crude oil with a Reid vapor pressure less than
13.8 kPa (2.0 psi) or whose physical properties preclude determination by the
recommended method is to be determined from available data and recorded if the estimated
true vapor pressure is greater than 6.9 kPa (1.0 psi).
(d) The following are exempt from the requirements of this section:
(1) Each owner or operator of each affected facility, which stores petroleum liquids with a
Reid vapor pressure of less than 6.9 kPa (1.0 psi), provided the maximum true vapor
pressure does not exceed 6.9 kPa (1.0 psi).
(2) Each owner or operator of each affected facility equipped with a vapor recovery and
return or disposal system in accordance with the requirements of § 60.112.

Status: In compliance. Records of tank contents are maintained. The maximum true vapor
pressure of the liquid during storage has been calculated and recorded.

NSPS, Subpart Ka – Tanks 6 and 44

60.112a(a)(2) The owner or operator shall equip each applicable storage vessel with a fixed roof with an
internal floating type cover. Each opening in the cover is to provide a projection below the
liquid surface and shall be equipped with a cover, seal, or lid which, is to be closed at all
times, except when the device is in use.

60.115a The owner or operator shall maintain records of petroleum liquid stored, period of storage,
and the maximum true vapor pressure for that liquid during storage.

Status: In compliance. Two tanks have been identified as applicable to the requirements of
Subpart Ka for the date of installation.

Tank Size Year Built Vapor Pressure Control Device
Tank 6* 3,360,000 gal. 1970 Varies Internal Floating
Tank 44 3,360,000 gal. 1981 Varies Internal Floating

All ladders, post, etc. have sleeves or gasketed sliding cobers and all openings are to
allow entrance of objects which go below floor level. The company has a daily gauge
sheet which shows the beginning and ending liquid level & vapor pressure. This
condition is also checked as part of the UACR inspections for all tanks.

* It should be noted that Tank 6 has been considered by Big West Oil to be subject to
Subpart Ka for historical reasons for potentially storing products that would have
triggered Subpart Ka applicability.

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NSPS, Subpart Kb – Tanks 5, 9, 28 29, 45, 56, 87, 90 & 95

60.112b(a) - The owner or operator of each storage vessel either with a design capacity greater than or
equal to 151 m3 containing a VOL that, as stored, has a maximum true vapor pressure equal
to or greater than 5.2 kPa but less than 76.6 kPa or with a design capacity greater than or
equal to 75 m3 but less than 151 m3 containing a VOL that, as stored, has a maximum true
vapor pressure equal to or greater than 27.6 kPa but less than 76.6 kPa, shall equip each
storage vessel with one of the following:
(1) A fixed roof in combination with an internal floating roof meeting the following
specifications:
(i) The internal floating roof shall rest or float on the liquid surface (but not necessarily in
complete contact with it) inside a storage vessel that has a fixed roof. The internal floating
roof shall be floating on the liquid surface at all times, except during initial fill and during
those intervals when the storage vessel is completely emptied or subsequently emptied and
refilled. When the roof is resting on the leg supports, the process of filling, emptying, or
refilling shall be continuous and shall be accomplished as rapidly as possible.
(ii) Each internal floating roof shall be equipped with one of the following closure devices
between the wall of the storage vessel and the edge of the internal floating roof:
(A) A foam- or liquid-filled seal mounted in contact with the liquid (liquid-mounted seal).
A liquid-mounted seal means a foam- or liquid-filled seal mounted in contact with the
liquid between the wall of the storage vessel and the floating roof continuously around the
circumference of the tank.
(B) Two seals mounted one above the other so that each forms a continuous closure that
completely covers the space between the wall of the storage vessel and the edge of the
internal floating roof. The lower seal may be vapor-mounted, but both must be continuous.
(C) A mechanical shoe seal. A mechanical shoe seal is a metal sheet held vertically against
the wall of the storage vessel by springs or weighted levers and is connected by braces to
the floating roof. A flexible coated fabric (envelope) spans the annular space between the
metal sheet and the floating roof.
(iii) Each opening in a noncontact internal floating roof except for automatic bleeder vents
(vacuum breaker vents) and the rim space vents is to provide a projection below the liquid
surface.
(iv) Each opening in the internal floating roof except for leg sleeves, automatic bleeder
vents, rim space vents, column wells, ladder wells, sample wells, and stub drains is to be
equipped with a cover or lid which is to be maintained in a closed position at all times (i.e.,
no visible gap) except when the device is in actual use. The cover or lid shall be equipped
with a gasket. Covers on each access hatch and automatic gauge float well shall be bolted
except when they are in use.
(v) Automatic bleeder vents shall be equipped with a gasket and are to be closed at all times
when the roof is floating except when the roof is being floated off or is being landed on the
roof leg supports.
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(vi) Rim space vents shall be equipped with a gasket and are to be set to open only when
the internal floating roof is not floating or at the manufacturer's recommended setting.
(vii) Each penetration of the internal floating roof for the purpose of sampling shall be a
sample well. The sample well shall have a slit fabric cover that covers at least 90 percent of
the opening.
(viii) Each penetration of the internal floating roof that allows for passage of a column
supporting the fixed roof shall have a flexible fabric sleeve seal or a gasketed sliding cover.
(ix) Each penetration of the internal floating roof that allows for passage of a ladder shall
have a gasketed sliding cover.
(2) An external floating roof. An external floating roof means a pontoon-type or double-
deck type cover that rests on the liquid surface in a vessel with no fixed roof. Each external
floating roof must meet the following specifications:
(i) Each external floating roof shall be equipped with a closure device between the wall of
the storage vessel and the roof edge. The closure device is to consist of two seals, one
above the other. The lower seal is referred to as the primary seal, and the upper seal is
referred to as the secondary seal.
(A) The primary seal shall be either a mechanical shoe seal or a liquid-mounted seal.
Except as provided in §60.113b(b)(4), the seal shall completely cover the annular space
between the edge of the floating roof and tank wall.
(B) The secondary seal shall completely cover the annular space between the external
floating roof and the wall of the storage vessel in a continuous fashion except as allowed in
§60.113b(b)(4).
(ii) Except for automatic bleeder vents and rim space vents, each opening in a noncontact
external floating roof shall provide a projection below the liquid surface. Except for
automatic bleeder vents, rim space vents, roof drains, and leg sleeves, each opening in the
roof is to be equipped with a gasketed cover, seal, or lid that is to be maintained in a closed
position at all times (i.e., no visible gap) except when the device is in actual use. Automatic
bleeder vents are to be closed at all times when the roof is floating except when the roof is
being floated off or is being landed on the roof leg supports. Rim vents are to be set to open
when the roof is being floated off the roof legs supports or at the manufacturer's
recommended setting. Automatic bleeder vents and rim space vents are to be gasketed.
Each emergency roof drain is to be provided with a slotted membrane fabric cover that
covers at least 90 percent of the area of the opening.
(iii) The roof shall be floating on the liquid at all times (i.e., off the roof leg supports)
except during initial fill un til the roof is lifted off leg supports and when the tank is
completely emptied and subsequently refilled. The process of filling, emptying, or refilling
when the roof is resting on the leg supports shall be continuous and shall be accomplished
as rapidly as possible.

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(3) A closed vent system and control device meeting the following specifications:
(i) The closed vent system shall be designed to collect all VOC vapors and gases
discharged from the storage vessel and operated with no detectable emissions as indicated
by an instrument reading of less than 500 ppm above background and visual inspections, as
determined in part 60, subpart VV, §60.485(b).
(ii) The control device shall be designed and operated to reduce inlet VOC emissions by 95
percent or greater. If a flare is used as the control device, it shall meet the specifications
described in the general control device requirements (§60.18) of the General Provisions.
(4) A system equivalent to those described in paragraphs (a)(1), (a)(2), or (a)(3) of this
section as provided in §60.114b of this subpart.
(b) The owner or operator of each storage vessel with a design capacity greater than or
equal to 75 m3 which contains a VOL that, as stored, has a maximum true vapor pressure
greater than or equal to 76.6 kPa shall equip each storage vessel with one of the following:
(1) A closed vent system and control device as specified in §60.112b(a)(3).
(2) A system equivalent to that described in paragraph (b)(1) as provided in §60.114b of
this subpart.
(c) Site-specific standard for Merck & Co., Inc.'s Stonewall Plant in Elkton, Virginia. This
paragraph applies only to the pharmaceutical manufacturing facility, commonly referred to
as the Stonewall Plant, located at Route 340 South, in Elkton, Virginia (“site”).
(1) For any storage vessel that otherwise would be subject to the control technology
requirements of paragraphs (a) or (b) of this section, the site shall have the option of either
complying directly with the requirements of this subpart, or reducing the site-wide total
criteria pollutant emissions cap (total emissions cap) in accordance with the procedures set
forth in a permit issued pursuant to 40 CFR 52.2454. If the site chooses the option of
reducing the total emissions cap in accordance with the procedures set forth in such permit,
the requirements of such permit shall apply in lieu of the otherwise applicable requirements
of this subpart for such storage vessel.

(2) For any storage vessel at the site not subject to the requirements of 40 CFR 60.112b (a)
or (b), the requirements of 40 CFR 60.116b (b) and (c) and the General Provisions (subpart
A of this part) shall not apply.

Status: In compliance. All applicable tanks are internal floating roof tanks, except Tank 5
which is constructed under the external floating roof option. These tanks are equipped
with the required controls. Tank 5 is now under Subpart CC, which requires tanks to
comply with 40 CFR 63.119 through 121 (Subpart G). No requirements in addition to
or more stringent than State regulations found in R307 were identified in Subpart G.

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60.113b(a) The owner or operator shall visually inspect the internal floating roof, the primary seal and
the secondary seal before filling. Any repairs needed shall be completed prior to filling the
tank. Seals shall be visually inspected at least once every 12 months after initial fill.
Repairs shall be made within 45 days. Additional visual inspections shall occur each time
the vessel is emptied and degassed. Notify the administrator at least 30 days prior to filling
each vessel.

Status: In compliance. Tank seals are inspected at least once every 12 months and after initial
fill. Records of all inspections are maintained on site.

60.113b(b) External floating roof - Measure gaps in primary seal during hydrostatic testing within 60
days of initial fill and at least once every five years thereafter. Measure gaps in secondary
seal during initial fill and once per year thereafter. Notify Administrator 30 days prior to
any gap measurements.

Status: In compliance. Tank 5 is subject. Tank seals are inspected annually (including gap
measurements) or when the tank is emptied and degassed, whichever comes sooner.
60.115b(a)(1)
Furnish the Administrator with a report that describes the control equipment and certifies
that the control equipment meets the specifications of § 60.112b(a)(1) and § 60.113b(a)(1).
This report shall be an attachment to the notification required by § 60.7(a)(3).
Status: In compliance. This report was submitted on October 17, 2003.
(2) Keep a record of each inspection performed as required by § 60.113b (a)(1), (a)(2), (a)(3),
and (a)(4). Each record shall identify the storage vessel on which the inspection was
performed and shall contain the date the vessel was inspected and the observed condition of
each component of the control equipment (seals, internal floating roof, and fittings).
Status: In compliance. Semi-annual inspections and annual rooftop gap inspection sheets are
kept on file.
(3) If any of the conditions described in § 60.113b(a)(2) are detected during the annual visual
inspection required by § 60.113b(a)(2), a report shall be furnished to the Administrator
within 30 days of the inspection. Each report shall identify the storage vessel, the nature of
the defects, and the date the storage vessel was emptied or the nature of and date the repair
was made.
Status: In compliance. Notifications are made as required. The notifications include any
problems discovered and dates repairs were made.

15
(4) After each inspection required by § 60.113b(a)(3) that finds holes or tears in the seal or seal
fabric, or defects in the internal floating roof, or other control equipment defects listed in §
60.113b(a)(3)(ii), a report shall be furnished to the Administrator within 30 days of the
inspection. The report shall identify the storage vessel and the reason it did not meet the
specifications of § 61.112b(a)(1) or § 60.113b(a)(3) and list each repair made.
Status: In compliance. Notifications are sent to the DAQ within 30 days of discovery if
problems are found during the semi-annual inspection. Summary information is also
included in semi-annual Subpart CC reports. No instances of seal gap measurement
failures were reported in the most recent report.

60.116b Copies of all records required must be kept for at least two years. Records containing
dimensions and contents shall be maintained.

Status: In compliance. Copies of all records are kept for the life of the tank. Contents are
recorded and throughput tracked.

EMISSIONS INVENTORY: The following figures are from DAQ’s 2023 emissions inventory
database:

Pollutant Tons/yr
PM10 ..................... 15.13
PM2.5 .................... 14.83
NOX .................... 112.98
SOX ...................... 70.54
CO ...................... 192.85
VOC ................... 295.84
NH3...................... 27.00

PREVIOUS ENFORCEMENT
ACTIONS: Warning, February 11, 2019 – Exceeding flare limit of no more than five
minutes of visible emissions in a two hour period.

NOV, October 18, 2021 – Exceeding flare limit of no more than five
minutes of visible emissions in a two hour period.

Warning January 11, 2023 - Failed H2S audit.

COMPLIANCE STATUS &
RECOMMENDATIONS: Big West Oil should be considered to be in compliance with the
regulations and AO conditions evaluated at the time of this inspection.

HPV STATUS: Not Applicable

COMPLIANCE
ASSISTANCE: None

RECOMMENDATION FOR
NEXT INSPECTION: Inspect as usual.

ATTCHMENT: VEO/Inspection form