DAQ-2024-011809

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DAQC-CI101530001-24
Site ID 10153 (B1)

MEMORANDUM

TO: FILE – STAR CASES, LLC dba ZERO MANUFACTURING – Aluminum Case &
Container Manufacturing Plant

THROUGH: Chad Gilgen, Minor Source Compliance Section Manager

FROM: Irene Tucker, Environmental Scientist

DATE: October 17, 2024

SUBJECT: FULL COMPLIANCE EVALUATION, Minor, Davis County

INSPECTION DATE: May 22, 2024

SOURCE LOCATION: 500 West 200 North
North Salt Lake, UT 84054

SOURCE CONTACTS: Darryl Remick, EHS Supervisor, 805-464-8280,
[e-mail]

OPERATING STATUS: In Operation

PROCESS DESCRIPTION: Zero Manufacturing produces high-end plastic, aluminum and
steel enclosures, luggage cases, and other components for
military, industrial, and commercial purposes. Parts are cut,
stamped, and formed to the proper size in the production facility.
Aluminum parts are formed by large presses and sent through a
heat-treating oven to harden the aluminum. Pressed parts are
cleaned in an oven with an afterburner to remove lubricant/oil.
Parts may be anodized (Type 2 Sulfuric Acid) and/or surface
coated. The source is equipped with painting and powder coating
systems. The powder coat is set using ultraviolet light ovens, and
painted parts may be baked. The major emission points are the
surface coating operations (filters), cleaning oven (afterburner),
polishing (cyclones), curing ovens, and anodizing tanks (water
scrubber). Currently, most of the products are manufactured for
the military and must meet military specifications. The military
specifications require higher VOC, hazardous air pollutant (HAP)
solvent born, oil based paints per military specification.

APPLICABLE REGULATIONS: Approval Order (AO) DAQE-AN101530010-21, dated
September 7, 2021

/ :
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SOURCE EVALUATION:
Name of Permittee: Permitted Location: Star Cases, LLC dba Zero Manufacturing Aluminum Case & Container Manufacturing Plant
500 West 200 North 500 West 200 North North Salt Lake, UT 84054 North Salt Lake, UT 84054 SIC Code: 3429: (Hardware, NEC)
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]
I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]

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]

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 two (2) years. [R307-401-8]

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 AO, 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]

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns.
[R307-107]

I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150]

I.8 The owner/operator shall submit documentation of the status of construction or modification 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. Zero Manufacturing has not exceeded any limits set forth in this
Approval Order. Zero Manufacturing maintains records for at least two years, and
maintains records of maintenance activities performed on approved equipment. According
to Zero Manufacturing, there have been no breakdowns resulting in an emissions event.
According to the 2023 Emissions Inventory Report, the emissions indicated compliance
with the PTEs of this Approval Order.
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SECTION II: PERMITTED EQUIPMENT

II.A THE APPROVED EQUIPMENT

II.A.1 Metal Fabrications

II.A.2 Prep and Cleaning
Parts preparation and cleaning with hexane

II.A.3 Paint Booths
Seven dry-filter paint booths

II.A.4 Powder Coating
One non-vented (close loop) powder paint booth

II.A.5 Can Washer
Fuel: Natural Gas
Rating: 2 MMBtu/hr, each

II.A.6 Etching and Anodizing Acid Scrubber
Anodizing acid bath with a minimum of 9,000 SCFM vapor removal system and a spray-tower acid-
mist scrubber

II.A.7 Etching Wash Tank
Weak (less than 5% concentrated) phosphoric acid rinse tank for etched products

II.A.8 Buffing Station Cyclone #1
Flow rate: 15,400 ACFM

II.A.9 Buffing Station Cyclone #2
Flow rate: 19,785 ACFM

II.A.10 Buffing Station Cyclone #3
Flow rate: 8,500 ACFM

II.A.11 Heat Treat Oven (HT02) with Incinerator
Fuel: Natural Gas
Rating: 2.4 MMBtu/hr
Volume Regulating Damper
Rating: 2.0 MMBtu/hr

II.A.12 Heat Treat Oven #28
Fuel: Natural Gas
Rating: 2.0 MMBtu/hr

II.A.13 Paint Curing Oven (PS9)
Fuel: Natural Gas
Rating: 2.5 MMBtu/hr

II.A.14 Wax Curing Oven (HPW2)
Fuel: Natural Gas
Rating: 1.5 MMBtu/hr

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II.A.15 One (1) Batch Oven (M01)
Fuel: Natural Gas
Rating: 0.75 MMBtu/hr

II.A.16 Aging Oven (AO48)
Fuel: Natural Gas
Rating: 2.0 MMBtu/hr
For Halliburton manufacturing line

II.A.17 Paint Curing Oven (PO1)
Powder paint curing oven
Rating: 3 MMBtu/hr

II.A.18 Three (3) Rotary Mold Ovens
Fuel: Natural Gas
Ratings: 4.5 MMBtu/hr
4.5 MMBtu/hr
2.0 MMBtu/hr

II.A.19 Bake Oven
Paint cure oven
Fuel: Natural Gas
Rating: 2.0 MMBtu/hr

II.A.20 Solvent Recycler
16-gallon closed-loop system batch solvent recycler

II.A.21 Air Make-up Units
Fuel Natural Gas
Rating: Less than 5 MMBtu/hr
For Informational Purposes Only

II.A.22 Various Shop Heaters
Fuel: Natural Gas
Ratings: Less than 5 MMBtu/hr
For Informational Purposes Only

II.A.23 Water Heaters
Various water heaters
Fuel: Natural Gas
Ratings: Less than 5 MMBtu/hr
For Informational Purposes Only
II.A.24 II.A.25
Office Space Heaters Various comfort heaters Fuel: Natural Gas Rating: Less than 5 MMBtu/hr For Informational Purposes Only Three (3) Sanding Booths Wet-collection sanding booths Status: In Compliance. There was no new or unapproved equipment observed onsite during this inspection.
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SECTION II: SPECIAL PROVISIONS

II.B REQUIREMENTS AND LIMITATIONS

II.B.1 Site-wide Requirement:

II.B.1.a The owner/operator shall not allow visible emissions from any stationary point or fugitive
emission source on site to exceed 10% opacity. [R307-401-8]

II.B.1.a.1 Opacity observations of emissions from stationary sources shall be conducted according to 40
CFR 60, Appendix A, Method 9. [R307-305-3]

Status: In Compliance. There were no visible emissions observed during this inspection.
The opacity observations were conducted according to 40 CFR 60, Appendix A, Method 9.
See the attachments for additional information.

II.B.1.b The owner/operator shall change the filters in the paint booth to a class #2 filter when paints
containing hexamethylene diisocyanate are used. The filters shall be disposed of promptly when
no longer serviceable according to manufacturer's specification. [R307-401-8]

Status: Not Applicable. According to Zero Manufacturing, they do not use any coatings
containing hexamethylene diisocyanate.

II.B.2 VOC & HAP Requirements

II.B.2.a The owner/operator shall not emit more than the following from evaporative sources
(painting, printing, coating, and/or cleaning) on site:

48.6 tons per rolling 12-month period of VOCs
5.5 tons per rolling 12-month period of an individual HAP
14.0 tons per rolling 12-month period of all HAPs combined
[R307-401-8]

II.B.2.a.1 The owner/operator shall calculate a new 12-month total within ten days of the end of
Each month using data from the previous 12 months. The owner/operator shall use a
mass-balance method to calculate emissions from evaporative sources. The
owner/operator may use the following equations with applicable units to comply with the
mass-balance method:

VOCs=[% VOCs by Weight/100] x [Density] x [Volume Consumed]
HAP= [% HAP by Weight/100] x [Density] x [Volume Consumed]
[R307-401-8]

II.B.2.a.2 The owner/operator shall use a mass-balance method to quantify any amount of VOCs
and HAPs reclaimed. The owner/operator shall subtract the amount of VOCs and HAPs
reclaimed from the quantities calculated above to provide the monthly total emissions
of VOCs and HAPs.

II.B.2.a.3 The owner/operator shall keep records each month of the following:

A. The name (as per SDS) of the VOC- and HAP-emitting material
B. The maximum percent by weight of VOCs and each HAP in each material used
C. The density of each material used
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D. The volume of each VOC- and HAP-emitting material used
E. The amount of VOCs and the amount of each HAP emitted from each material
F. The amount of VOCs and the amount of each HAP reclaimed and/or controlled from
each material
G. The total amount of VOCs, the total amount of each HAP, and the total amount of all
HAPs combined emitted from all materials (in tons).

[R307-401-8]

Status: In Compliance. In a rolling 12-month period from June 2023 to May 2024,
the VOC and HAP emissions are as follows:

1.64 tons per rolling 12-month period of VOCs
0.31 tons per rolling 12-month period of an individual HAP
0.79 tons per rolling 12-month period of all HAPs combined

See the attachments for additional information.

II.B.2.b The owner/operator shall not use any material with a VOC content greater than the
Applicable requirements of R307-350 or 3.5 lbs of VOC per gallon of coating, as applied,
whichever is lower. [R307-350, R307-401-8]

11.B.2.b.1 The owner/operator shall:

A. Record the VOC contents of each load of paint delivered to the coating applicator.

B. Keep records in the operations log.

[R307-401-8]

Status: In Compliance. The VOC content of the coatings reviewed indicated
compliance in pounds of VOC per gallon of coating. See the Environmental Data
Sheets in the attachments for additional information. Zero Manufacturing maintains
an operations log of the VOC contents of each load of paint. See the attachments for
additional information.

11.B.3 Etching and Anodizing Acid Scrubber Requirements:

11.B.3.a The owner/operator shall not allow the flow rate of the scrubber liquor to be lower than
27 gallons per minute. [R307-401-8]

11.B.3.a.l The owner/operator shall:

A. Install, calibrate, maintain and operate a device to monitor the liquor level of the
scrubber at all times.

B. Place monitoring equipment in a location where an operator/inspector can safely
Read the output at any time.

C. Ensure monitor readings are accurate within 0.10 gallons per minute.

D. Maintain a continuous record of the instrument's readings.

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E. Maintain a weekly instrument reading log when the automatic reading device is
out of order.

Status: In Compliance. Records reviewed of the Scrubber flow rate indicated
compliance and were greater than 27 gallons per minute. See the Scrubber Flow
rates in the attachments.

The Scrubber Flow rates can be monitored continuously, and the panel can be
easily and safely read at all times. Zero Manufacturing knows to log readings
manually when the automatic reading device is out of order.

11.B.4 Heat Treat Oven with Incinerator Requirements:

11.B.4.a The owner/operator shall maintain the temperature of the thermal incinerator at or above
1,400°F. The temperature may not drop below l,400°F for more than five (5) minutes per
60-minute period. [R307-401-8]

11.B.4.a.1 The owner/operator shall:

A. Install, calibrate, maintain, and operate a device to monitor the operating temperature
of the thermal incinerator within 25°F.

B. Place the monitoring device in a location where an inspector/operator can safely
read the output at any time.

C. Maintain a continuous record of the instrument readings.

D. Record the temperature of the thermal incinerator weekly when automatic recording
device is out of order.

[R307-401-8]

Status: In Compliance. Temperature records reviewed of the Thermal Incinerator
were at or above 1,400°F Scrubber. See the attachments for additional information.
The temperature panel can be safely observed and read at all times. The records are
maintained continuously. Zero Manufacturing knows to log readings
manually when the automatic reading device is out of order.

Section III: APPLICABLE FEDERAL REQUIREMENTS

In addition to the requirements of this AO, all applicable provisions of the following federal programs have
been found to apply to this installation. This AO in no way releases the owner or operator from any liability
for compliance with all other applicable federal, state, and local regulations including UAC R307.

There are no applicable Federal requirements identified at this time.

AREA SOURCE RULES EVALUATION:

The following Area Source Rules were evaluated during this inspection:

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R307-325 - Ozone Nonattainment and Maintenance Areas: General Requirements

Status: In Compliance. During this inspection, coatings were observed in closed containers and
stored in cabinets when not in use. There were no spills observed.

R307-342 - Adhesives and Sealants

Status: In Compliance. Zero Manufacturing is claiming the R307-342-3(2)(d) exemption for
“Operations that are exclusively covered by Department of Defense military technical specifications
and standards and performed by a Department of Defense contractor and/or on site at installations
owned and/or operated by the United States Armed Forces.” Zero manufacturing maintains records
of the adhesives and sealants used.

R307-350 - Miscellaneous Metal Parts and Products Coatings

Status: In Compliance. Zero Manufacturing is claiming the R307-350-3(1)(g) exemption for
“Operations that are exclusively covered by Department of Defense military technical data and
performed by a Department of Defense contractor and/or on site at installations owned and/or
operated by the United States Armed Forces.” Zero manufacturing maintains records of the
Miscellaneous Metal Parts and Products Coatings used.

EMISSION INVENTORY: Status: In Compliance. According to the 2023 Emissions Inventory Report,
the emissions indicated compliance with the PTEs of this Approval Order.

Listed below are the Actual Emissions Inventory provided from Star Cases, LLC dba Zero Manufacturing –
Aluminum Case & Container Manufacturing Plant. A comparison of the estimated total potential
emissions (PTE) on Approval Order (AO) DAQE-AN101530010-21, dated September 7, 2021. PTE are
supplied for supplemental purposes only.

Criteria Pollutant PTE tons/yr Actuals tons/yr
Carbon Monoxide 6.13 2.25
Lead Compounds 0.01 0.003
Nitrogen Oxides 23.07 2.7
Particulate Matter - PM10 6.70 0.91
Particulate Matter - PM2.5 3.30 0.91
Sulfur Dioxide 0.15 0.05
Volatile Organic Compounds 49.82 5.19

Hazardous Air Pollutant PTE lbs/yr Actuals lbs/yr
2,4-Toluene Diisocyanate (CAS #584849) 40
Chromium Compounds (CAS #CMJ500) 40
Glycol Ethers (CAS #EDF109) 1
Hexane (CAS #110543) 340
Lead Compounds (CAS #LCT000) 20
Methanol (CAS #67561) 1
Methyl Isobutyl Ketone (Hexone) (CAS #108101) 40
Toluene (CAS #108883) 240
Total HAPs (CAS #THAPS) 27080
Xylenes (Isomers And Mixture) (CAS #1330207) 200
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PREVIOUS ENFORCEMENT
ACTIONS: No enforcement actions within the past five years.

COMPLIANCE STATUS &
RECOMMENDATIONS: Zero Manufacturing is in compliance with the conditions in Approval
Order (AO) DAQE-AN101530010-21, dated September 7, 2021.
Zero Manufacturing maintains good housekeeping practices.

HPV STATUS: Not Applicable.

RECOMMENDATION FOR
NEXT INSPECTION: Inspect as usual. Required PPE includes safety glasses.

NSR RECOMMENDATIONS: None at this time.

ATTACHMENTS: Applicable Supporting Documentation Included