OREGON DEPARTMENT OF ENVIRONMENTAL QUALITY

OREGON TITLE V OPERATING PERMIT REVIEW REPORT

Eastern Region

2146 N.E. 4th, #104

Bend, OR 97701

TABLE OF CONTENTS

LIST OF ABBREVIATIONS USED IN THIS REVIEW REPORT  3

INTRODUCTION  4

PERMITTEE IDENTIFICATION  5

FACILITY DESCRIPTION  5

EMISSIONS UNIT AND POLLUTION CONTROL DEVICE IDENTIFICATION  7

EMISSIONS LIMITS AND STANDARDS, TESTING, MONITORING, AND RECORDKEEPING REQUIREMENTS  11

STATE REQUIREMENTS NOT INCLUDED IN THE SIP (OAR CHAPTER 340)  11

SIP REQUIREMENTS (OAR CHAPTER 340)  11

PSD REQUIREMENTS (EPA 1977 PSD PERMIT)  15

NESHAP REQUIREMENTS  16

Subpart A General Provisions  16

Subpart LL Requirements  21

Subpart RRR Requirements  26

OTHER FEDERAL REQUIREMENTS  30

INSIGNIFICANT EMISSIONS UNITS  31

PLANT SITE EMISSION LIMITS  32

COMPONENTS OF THE NETTING BASIS  32

SIGNIFICANT EMISSION RATE  33

HAZARDOUS AIR POLLUTANTS  33

GENERAL BACKGROUND INFORMATION  34

COMPLIANCE HISTORY  34

SOURCE TEST RESULTS  35

PUBLIC NOTICE  35

EMISSIONS DETAIL SHEETS  36

ATTACHMENTS:

Emission Detail Sheets

Summary of source test results (1995-2000)

LIST OF ABBREVIATIONS USED IN THIS REVIEW REPORT

INTRODUCTION

1.  This is a renewal of the Oregon Title V Operating Permit (Number 33-0001) for Northwest Aluminum Company (NWA) that was issued on July 2, 2001 and scheduled to expire on May 1, 2006. A complete and timely renewal application was submitted by the permittee, so the existing permit will remain in effect until this renewal is issued.

a.  The primary aluminum production plant is not currently operating.

b.  The secondary aluminum production plant is operating, including Northwest Specialties and one or more of the primary casthouse furnaces without reactive fluxing.

c.  The permittee is required to notify the Department at least 30 days prior to restarting the primary aluminum production plant.

2.  In accordance with OAR 340-218-0120(1)(f), this review report is intended to provide the legal and factual basis for the draft permit conditions. In most cases, the legal basis for a permit condition is included in the permit by citing the applicable regulation and quite often also provides the factual basis for the conditions. Where the factual basis is not clear from the regulation because the regulation is not specific and only provides general requirements, this review report is used to provide a more thorough explanation of the factual basis for the draft permit conditions.

3.  There were not any permit revisions during the previous permit term. During this renewal, the permit is being revised based on some minor changes requested by the permittee and recent changes to rules. The changes are described below:

PERMITTEE IDENTIFICATION

4.  Northwest Aluminum Company (NWA) owns and operates a vertical stud soderberg (VSS) primary aluminum production plant, employing Sumitomo technology, located at 3313 W. Second Street, The Dalles, Oregon. NWA also owns and operates Northwest Aluminum Specialties, Inc., a secondary aluminum casting operating at the same address.

Northwest Aluminum Specialties, Inc. was permitted under ACDP number 33-0029 and built in 1990. The secondary facility was added to the Title V permit for the primary facility because of the definition of a major source under Part 70 of the Federal Clean Air Act Amendments of 1990, which includes ownership/control, contiguous/adjacent property, and same major SIC/supporting activities as criteria. Northwest Aluminum Specialties, Inc. met all of these criteria, so the requirements from permits 33-0001 and 33-0029 have been included in a single Oregon Title V Operating Permit.

NWA is located on 422 acres of land in The Dalles Industrial Park, zone (M-2), adjacent to the Columbia River and The Columbia River Gorge National Scenic area. NWA employs 475 people and produces 97,500 tons of aluminum from the primary production plant, 22,500 tons of scrap re-melt in the casthouse, and 90,000 tons of secondary aluminum in Northwest Aluminum Specialties.

FACILITY DESCRIPTION

5.  At Northwest Aluminum (NWA), primary aluminum production is the main operation, along with secondary aluminum melting in the 2 casthouses. The aluminum reduction in NWA’s cell lines (A-1) is a continuous operation for 365 days per year. There are five cell rooms at NWA with 60 reduction cells (pots) in each room. Two and one half rooms constitute a line for power alignment. Therefore, there are two distinct potlines. The average life of a reduction cell is 2,100 to 2,700 days, then it is rebuilt and put back into service. Currently, NWA is only operating one of the two potlines, but they may operate both potlines in the future.

Aluminum metal is produced by electrolytic reduction using direct current voltage in a sodium aluminum fluoride electrolyte (Na₃AlF₆) called cryolite. Operating temperatures in the pot approach 1700°F. Alumina and other additives are spread on the frozen crust and then mechanically worked into the molten electrolyte by breaking the crust. This is performed 9 times per day and 1 time per day in the room with experimental feeders. The electrolytic process reduces the alumina into aluminum and oxygen ions. The oxygen gas reacts with the carbon anode forming carbon oxides. A portion of the molten aluminum is removed every other day from the cell and transported to the casting facility (A-3).

The sides and the ends of the anode are equipped with a permanent cast iron skirt, which allows for the capture of organic emissions from the hooded part of the cell and ducts them into a burner at the end. The burner combusts the captured emissions and sends them to the Dry Scrubber Baghouse (A-1b.1) for emission control and scrubbing with virgin ore to capture particulate matter and fluoride. The gases then pass through a Wet SO₂ Scrubber (A-1b.2) for sulfur dioxide scrubbing. Any fugitive emissions in the cell lines are drawn to the Secondary Roof System (A-1a) for scrubbing with water before leaving the facility. The operation is dependent upon a constant supply of electricity and when it is shut down, the operation shuts down until the electrical current is restored. The cells are kept sealed to hold the heat in, thus minimizing emissions during a temporary shutdown.

The paste plant (A-2) provides carbon briquettes by processing and blending appropriate raw materials for the anodes in the Cell Lines (A-1). The mixing system has two duplicate lines that run for 72-96 hours a week, producing 950 tons of briquettes per week, 50 weeks per year. The system is designed to run 120 hours a week, producing 1,920 tons per week for both internal use and sales to customers. The lines are hooded to capture dust and fumes. Fumes are sent to the Dry Coke Scrubber (A-2a), where coke is injected to scrub the fumes, and then to the Dust Collector Baghouse (A-2b). Materials collected in both control devices are then recycled into the system. The heating process for blending the petroleum coke and coal tar pitch uses a dowtherm boiler, which is powered by natural gas (A-3d). The heat exchange helps to blend the two raw materials, which are then extruded out and immediately frozen by water on the cooling belt. The briquettes are conveyed to and stored in the briquette silos in the Cell Lines and the covered pad (A-4e). If there is a power loss, the system will not operate until power is restored.

When molten metal from the Cell Lines (A-1) leaves, it is taken to the Casthouse (A-3) for processing. The casthouse operates 24 hours per day, 365 days per year. The metal is analyzed and put into one of three holding (reverbatory) furnaces (A-3a.1,2,3) or the Liquid Metal Transfer furnace (A-3a.4), which are heated by natural gas and propane as a backup. The metal in the holding furnaces are then prepped for casting, which depending upon its alloy, whether it is degassed by mint units or by fluxing with nitrogen and chlorine. The mint units were to be installed in 1995 and two were installed but they did not work as well as intended. The mint units were replaced with a Porous Plug fluxing unit and Pyrotek Rotating fluxing unit. The metal is then cast into billets (logs), T-ingots, or sows using water for cooling. The billet is sent to the homogenizing furnaces (A-3b.1,2) for grain restructuring, which is done by re-heating the metal using electricity or natural gas. Or the billet and T-ingots are sent to the saws (A-3c) for cutting to size and then shipment. The casthouse also has a scrap re-melt furnace (A-3a.5) that is tied into the holding furnaces. This re-melt furnace also uses natural gas for melting of extrusion scrap. The metal is then transferred to the holding furnaces by pump for casting. The casthouse operates only on natural gas or propane as backup. If both of these are discontinued, then the metal is poured into molds and air cooled until the gas is restored.

Molten metal from the casthouse (A-3) is also sent to the Secondary casthouse (B-3) for processing. This facility also remelts extrusion scrap for casting and alloying in its 4 electric induction furnaces (B-4a.1-4). From the induction furnaces, the metal is transferred to the 3 Tilt holding furnaces (B-3c), which are heated with natural gas. The metal is then degassed through the sniff units or fluxed with nitrogen, before casting with recycled water. From the casting tables, the billet (logs) are sent to the 4 gas fired homogenizers (B-3d) for grain restructuring. The finished product is sent to the saws for cutting (B-3e) and packaging. The chips from the saws are caught in an outside-enclosed bin. Without electricity, the facility can run on gas until electricity is restored for the induction furnaces. A small induction furnace for research and development (B-3b) is used to help develop new alloys and products for the facility and operated only during the workweek. There is also a scrap metal shredder (B-5) located at NWA Specialties.

The permit includes provisions for a pilot study to be performed to evaluate a control system for the 4 induction furnaces (B-4a.1-4) and 3 Tilt holding furnaces (B-3c) at NWA Specialties. Once this study is completed, NWA will submit final design plans and complete installation of the controls for all of the inductions/tilt holding furnaces.

Material handling (A-4) at NWA involves all the raw materials that come into the facility and materials shipped out for reclaim or disposal. All raw materials either come in by rail or by truck. The alumina ore comes in by rail and is unloaded in the Unloading building (A-4a) by dropping the ore into a pit that is pumped to the silos, which have baghouses. The silos have a capacity of 9,000 STons (A-4a). The ore is conveyed by pneumatic air slide to the handling silos (A-4b), which have a capacity of 4,500 STon each and have baghouses for particulate control. The Paste Plant (A-2) receives its material by rail at the Coke Unloading area (A-4c), 3,600 STon capacity, and the Pitch Unloading area(A-4d), 5,500 STon capacity. The coke and pitch are dumped into pits for pumping to their storage areas. The finished coke (briquettes) are stored in silos and on a covered pad (A-4e) with a 5,000 STon holding capacity. Aluminum Fluoride Unloading (A-4f) is either by rail or truck and is pumped into a silo with a 1,000 STon capacity. The casthouses (A-3 and B-3) generate dross from the holding furnaces, which is skimmed from the surface of molten metal and then stored in a covered slab (A-4g) for shipment to a reclaim facility. Fugitives are generated when loading of the dross material into rail cars. Another form of materials handling is that of construction debris in the Solid Waste handling area (A-4h). A future building for handling Spent Potliner (pot debris) may be built and will have an air control system on it (A-4i). The materials handling takes place around the clock when rail cars are present with alumina ore, coke, or pitch. The time frame is almost 365 days a year. Aluminum Fluoride, Dross handling and Solid Waste disposal is only during daylight hours. As long as the facility is running, then there is material handling.

EMISSIONS UNIT AND POLLUTION CONTROL DEVICE IDENTIFICATION

6.  The emissions units at this facility include the following:

There are five saws in the casthouse for cutting T-ingot and billet and ten automatic puck saws in NWA Products for cutting to certain sizes for shipment. These saws exhaust inside buildings and do not emit to the atmosphere. Therefore, the saws were not included as regulated emissions units.

7.  Categorically insignificant activities include the following:

•  Constituents of a chemical mixture present at less than 1% by weight of any chemical or compound regulated under Divisions 20 through 32 of this chapter, or less than 0.1% by weight of any carcinogen listed in the U.S. Department of Health and Human Service's Annual Report on Carcinogens when usage of the chemical mixture is less than 100,000 pounds/year

•  Evaporative and tail pipe emissions from on-site motor vehicle operation

•  Distillate oil, kerosene, and gasoline fuel burning equipment rated at less than or equal to 0.4 million Btu/hr

•  Natural gas and propane burning equipment rated at less than or equal to 2.0 million Btu/hr

•  Office activities

•  Food service activities

•  Janitorial activities

•  Personal care activities

•  Groundskeeping activities including, but not limited to building painting and road and parking lot maintenance

•  On-site recreation facilities

•  Instrument calibration

•  Maintenance and repair shop

•  Automotive repair shops or storage garages

•  Air cooling or ventilating equipment not designed to remove air contaminants generated by or released from associated equipment

•  Refrigeration systems with less than 50 pounds of charge of ozone depleting substances regulated under Title VI, including pressure tanks used in refrigeration systems but excluding any combustion equipment associated with such systems

•  Bench scale laboratory equipment and laboratory equipment used exclusively for chemical and physical analysis, including associated vacuum producing devices but excluding research and development facilities

•  Temporary construction activities

•  Warehouse activities

•  Accidental fires

•  Air vents from air compressors

•  Electrical charging stations

•  Blueprint making

•  Routine maintenance, repair, and replacement such as anticipated activities most often associated with and performed during regularly scheduled equipment outages to maintain a plant and its equipment in good operating condition, including but not limited to steam cleaning, abrasive use, and woodworking

•  Electric motors

•  Storage tanks, reservoirs, transfer and lubricating equipment used for ASTM grade distillate or residual fuels, lubricants, and hydraulic fluids

•  Natural gas, propane, and liquefied petroleum gas (LPG) storage tanks and transfer equipment

•  Pressurized tanks containing gaseous compounds

•  Storm water settling basins

•  Paved roads and paved parking lots within an urban growth boundary

•  Hazardous air pollutant emissions of fugitive dust from paved and unpaved roads except for those sources that have processes or activities that contribute to the deposition and entrainment of hazardous air pollutants from surface soils

•  Health, safety, and emergency response activities

•  Emergency generators and pumps used only during loss of primary equipment or utility service

EMISSIONS LIMITS AND STANDARDS, TESTING, MONITORING, AND RECORDKEEPING REQUIREMENTS

8.  There have not been any changes to the requirement contained in the previous permit. However, there are two requirements being added to the permit as a result of changes to the regulations during the pervious permit term. These requirements are not included in the SIP, so they are only enforceable by DEQ. Provided below is a discussion of all of the requirements applicable to this facility and the monitoring required to satisfy the Title V monitoring requirements.

STATE REQUIREMENTS NOT INCLUDED IN THE SIP (OAR CHAPTER 340)

9.  The nuisance regulations contained in OAR 340-208-0300 through 340-208-0450 are now applicable to all sources in all areas of the state. They were previously only applicable to sources located in certain special control areas. These regulations include requirements prohibiting nuisances (OAR 340-208-0300), masking of emissions (OAR 340-208-0400), and fallout of particulate matter greater than 250 microns (OAR 340-208-0450). OAR 340-208-0400 is included in the General Conditions. The other two requirements are included in the permit as permit conditions 4 and 5. The permittee is required to maintain a complaint log and investigate any complaints to determine the validity of the complaint and take corrective action, if appropriate for resolving the complaint.

SIP REQUIREMENTS (OAR CHAPTER 340)

10.  SIP requirements that are applicable to both the primary and secondary aluminum facilities:

a.  Fuels. The permit does not allow the permittee to use residual fuel oil, distillate fuel oil, or coal because those fuels have sulfur, which would cause sulfur dioxide emissions in excess of the Plant Site Emission Limits. The authority for this requirement is PSEL rule 0AR 340-222-0040(6). As a result of the this requirement, the fuel sulfur requirements in Division 228 are not applicable to this facility. [Permit Condition 6]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

ii.  Monitoring requirements: The permittee is required to monitor the type and amount of fuel used on a monthly basis. [Permit Condition 63]

iii.  Recordkeeping requirements: The permittee is required to keep records of type and amount of fuel used on a monthly basis. [Permit Condition 109.d]

b.  Fugitive dust control. The requirement to minimize fugitive dust emissions contained in OAR 340-208-0210(2) applies to this facility because it is located in a special control area. The permit condition includes source specific work practice requirements for minimizing fugitive emissions. [Permit Condition 7]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

ii.  Monitoring requirements: Since fugitive emissions could cause nuisance conditions off-site, the permittee is required to keep a log of complaints, investigate the complaint, make a determination as to the validity of the complaint, and resolve any problems at the plant that were the cause of the complaint. [Permit Condition 64] In addition, the permittee is required to perform weekly inspections of storage containers and the cell room windows and doors because these could be sources of fugitive emissions. [Permit Condition 65]

iii.  Recordkeeping requirements: The permittee is required to maintain a complaint log and records of the weekly inspections. [Conditions 109.j and 109.k]

c.  Pollution control device downtime. The Air Contaminant Discharge Permit (ACDP) issued on 4/13/92 included a requirement for monitoring the occurrence and length of downtime for all pollution control devices. By definition, all ACDP conditions are federally enforceable applicable requirements, unless revoked or modified. [Permit Condition 8]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

ii.  Monitoring requirements: The permittee is required to monitor pollution control device downtime. [Permit Condition 66]

iii.  Recordkeeping requirements: The permittee is required to keep records of pollution control device downtime. [Permit Condition 109.t]

d.  Pollution control device efficiency. OAR 340-236-0150(1)(f) requires that the permittee monitor changes in control device efficiency. [Permit Condition 9]

i.  Testing requirements: Particulate and fluoride efficiency testing is required for one of the secondary scrubber control systems each quarter. Inlet testing was required of the wet SO₂ scrubber for efficiency determinations, but is no longer required because years of testing has shown good efficiency when the control device is operating properly and the permit requires continuous parametric monitoring to ensure that the control device is being operated properly. [Permit Condition 47]

ii.  Monitoring requirements: The permittee is required to continuously monitor control device parameters that are indicators of control device performance. [Permit Condition 67]

iii.  Recordkeeping requirements: The permittee is required to keep records of control device efficiency (emission test results) and control device parameter data. [Permit Conditions 109.m, 109.o, and 109.s]

e.  Source Emissions Reduction Plan (SERP). The ACDP issued on 4/13/92 included a requirement for developing a SERP and implementing the plan if the Department declares an air pollution episode for The Dalles area. By definition, all ACDP conditions are federally enforceable applicable requirements, unless revoked or modified. [Permit Condition 10]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

ii.  Monitoring and recordkeeping requirements: The permittee is required to keep records of air pollution episodes and the emission reduction actions taken as required by the SERP. [Permit Condition 68]

11.  SIP requirements that are applicable to the primary aluminum production facility:

a.  Fluoride ion emission limits. OAR 340-236-0120(3)(a) requires that total fluoride ion not exceed 3.5 pounds per ton of aluminum produced (lb/TAP) as a monthly average, 2.5 lb/TAP as a yearly average, and 22 tons per month. However, the NESHAP standards are more stringent than the state standards and the same test methods and monitoring are used to determine compliance so the state limits in terms of lbs/TAP are not included in the permit. The state limit in terms of tons/month is retained. [Permit Condition 14]

i.  Testing requirements: See item 15.a.i below. [Permit Condition 47]

ii.  Monitoring requirements: See item 15.a.ii. [Permit Condition 70]

iii.  Recordkeeping requirements: The permittee is required to keep records of control device efficiency (emission test results) and control device parameter data. [Permit Conditions 109.m, 109.r, and 109.x]

b.  Particulate matter emission limits. OAR 340-236-0120(3)(b) requires that particulate matter not exceed 13.0 pounds per ton of aluminum produced (lb/TAP) as a monthly average and 10 lb/TAP as a yearly average. [Permit Conditions 15 and 16]

i.  Testing requirements: Particulate matter emissions tests are required at least once each quarter for each potline using the test methods and procedures approved in NWA’s Air Emissions Testing Quality Assurance Plan. OAR 340-238-0140 requires monthly testing unless the Department approves a reduced testing frequency. NWA has requested and the Department approves quarterly testing instead of monthly testing based on the same criteria as used for approving reduced testing frequency for the NESHAP requirements (e.g., the average results of the previous 24 months testing is less than 60% of the standard and no monthly result was greater than 75% of the standard). For particulate matter the average monthly result was 6.22 lb/TAP and 60% of the monthly standard is 7.8 lb/TAP. If the standard is exceeded during a quarterly test, the permittee must begin monthly testing for at least 12 months. If the average for 12 months is less than 60% of the standard and no single month value is greater than 75% of the standard, then the permittee may resume quarterly testing. [Permit Condition 47]

ii.  Monitoring requirements: The permittee is required to continuously monitor control device parameters that are indicators of control device performance. [Permit Condition 70] (See also the discussion of the Compliance Assurance Monitoring requirements.)

iii.  Recordkeeping requirements: The permittee is required to keep records of control device efficiency (emission test results) and control device parameter data. [Permit Conditions 109.m and 109.w]

c.  Particulate emissions limit. Since this facility began operations prior to June 6, 1970, the particulate matter limit of 0.2 gr/dscf applies to the potlines (primary and secondary control systems) as specified in OAR 340-226-0210(1)(a). [Permit Condition 17]

i.  Testing requirements: See item b.i [Permit Condition 47]

ii.  Monitoring requirements: See item 15.a.ii [Permit Condition 70 and 78-82]

iii.  Recordkeeping requirements: The permittee is required to keep records of control device efficiency (emission test results) and control device parameter data. [Permit Conditions 109.m, 109.o, and 109.s]

d.  Visible emissions limit. As specified in OAR 340-236-0120(3)(d), visible emissions from the primary aluminum production facility shall not exceed 20% opacity from any source at any time. [Permit Condition 22]

i.  Testing requirements: Official reference method testing is not required because of the extensive monitoring that is required as discussed below. If a compliance test is performed, the permittee would use the method and procedures specified in the definition of opacity in OAR 340-200-0020. [Permit Condition 47]

ii.  Monitoring requirments: The permittee is required to perform routine inspections of the control devices (primary and secondary scrubbers), monitor the ore feed schedules to minimize fugitive emissions, and perform daily observations to determine if visual emission are abnormal. The daily visible emissions observations are required by the NESHAP. [Permit Conditions 80 through 82]

iii.  Recordkeeping requirements: The permittee is required to maintain records of the ore feed schedules, control device inspections, control device parameter data, and daily visible emissions observations. The records must also include any maintenance activities and corrective action when a visible emissions are observed to be abnormal or control parameter limits are exceeded. [Permit Conditions 109.k, m, and n, 109.h, i, and j]

e.  Pot feeding schedules. In order to minimize fugitive particulate emissions, NWA is required to use a consecutive feeding schedule when using truck feeders to feed alumina and alloys to the pot cells. This is a work practice requirement to ensure compliance with OAR 340-236-0120(3)(d). [Permit Condition 23]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

ii.  Monitoring and recordkeeping requirements: The permittee is required to maintain records of the pot cell feeding schedules. [Permit Condition 72]

f.  Sulfur dioxide limit. The ACDP issued on 4/13/92 included an SO₂ limit of 70 ppm from the Wet SO₂ scrubber. By definition, all ACDP conditions are federally enforceable applicable requirements, unless revoked or modified. [Permit Condition 24]

i.  Testing requirements: The permttee is required to test the Wet SO₂ scrubber for SO₂ emissions at the same time that the PM and fluoride tests are being performed. [Permit Condition 47]

ii.  Monitoring requirements: The permittee is required to continuously monitor control device parameters that are indicators of control device performance. [Permit Condition 47] (See also the discussion of the Compliance Assurance Monitoring requirements.)

iii.  Recordkeeping requirements: The permittee is required to keep records of control device efficiency (emission test results) and control device parameter data. [Conditions 109.m and 109.y]

g.  Paste leaks. The ACDP issued on 4/13/92 included a requirement to monitor paste leaks from the anodes of the pots and take corrective action to minimize fugitive emissions. By definition, all ACDP conditions are federally enforceable applicable requirements, unless revoked or modified. [Permit Condition 25]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

ii.  Monitoring requirements and recordkeeping requirements: The permittee is required to maintain records of paste leaks from the anodes of the pots along with any corrective action taken to minimize fugitive emissions. [Permit Condition 74]

12.  SIP requirements that are applicable to other emissions units:

a.  Particulate matter emissions limits. Emissions units A-2a, A-2b, A-2d, A-3a.1, A-3a.2, A-3a.3, A-3a.4, A-3a.5, A-3b.1, A-4a, A-4b, A-4f are all subject to the 0.2 gr/dscf limit specified in OAR 340-226-0210(1)(a) because they were installed prior to June 6, 1970. Emissions units B-3c.1, B-3c.2, B-3c.2 and B-3d are subject to the 0.1 gr/dscf limit specified in OAR 340-226-0210(1)(b) because they were installed after June 6, 1970. Emissions unit A-2c is subject to the 0.2 gr/dscf limit corrected to 12% CO₂ or 50 % excess air as specified in OAR 340-228-0210(1)(a) because it is a boiler that was installed prior to June 6, 1970. [Permit Conditions 30, 31, and 32]

i.  Testing requirements: Emissions units A-2a, A-2b, A-2d, A-4a, A-4b, and A-4f have baghouse controls for which the Department is not requiring testing because the routine monitoring described below should be sufficient for providing a reasonable assurance of compliance with the grain loading limit. In general, emissions from properly operated baghouses are considerably less than the grain loading limits. Emissions units A-2c, A-3a.4, A-3a.5, A-3b, and B-3d are combustion devices (furnaces and boilers) that burn only natural gas or propane. In general, particulate emissions from the combustion of natural gas are insignificant because it is a clean burning fuel. Therefore, testing is not required for those emissions units. Emission units A-3a.1, A-3a.2, A-3a.3, B-3c.1, B-3c.2, and B-3c.3 are also natural gas combustion devices, but particulate emissions are generated during the fluxing operations. It is estimated that the emissions are greater than 5 tons per year for these processes, so the Department is requiring that the emissions be tested at least once during the permit term. Since emissions units A-3a.1, A-3a.2, and A-3a.3 are similar units, only one test is required to be performed on one of the units. The same is true for emissions units B-3c.1, B-3c.2, and B-3c.3. In addition, the tests may be performed within 2 years after the permit is issued so it may be possible to coordinate the tests with the testing that is required by the secondary aluminum MACT standard. [Permit Condition 49]

ii.  Monitoring requirements: For the emissions units with baghouses (A-2a, A-2b, A-2d, A-4a, A-4b, and A-4f), the permittee is required to inspect the control devices at least once every week. For the natural gas fired emissions units (A-2c, A-3a.4, A-3a.5, and B-3d), the permittee is not required to do any monitoring other than keeping records of the type and amount of fuel burned in the devices. The assumption being that as long as natural gas or propane are burned, the emissions standards will not be exceeded. For the fluxing operations (emissions units A-3a.1, A-3a.2, A-3a.3, B-3c.1, B-3c.2, and B-3c.3), the permittee is required to perform a visible emissions test using EPA Method 9 at least once each month. While there is not a direct correlation between visible emissions and particulate emissions, it is assumed that the emissions will be less than the standard provided the visible emissions are less than 20% opacity. [Permit Condition 100]

iii.  Recordkeeping requirement: The permittee is required to keep records of the weekly baghouse inspections, type and amount of fuel burned, and the monthly visible emissions tests. [Permit Conditions 109.d, 109.l, and 109.o]

b.  Visible emission limits. Emissions units A-2a, A-2b, A-2c, A-2d, A-3a, A-3b, A-4a, A-4b, A-4c, A-4d, A-4e, A-4f, and A-4g are subject to the visible emissions limit specified by OAR 340-236-0120(3)(d) because these are primary aluminum production sources. The visible emissions limit of 20% opacity is not to be exceeded at any time. Emissions units B-3c and B-3d are part of the secondary aluminum production plant so they are subject to the general state limit specified in OAR 340-208-0110(2). This regulation requires that visible emissions not be equal to or greater than 20% opacity for more than an aggregate of 3 minutes in any 60-minute period. Note that emissions units A-4c, A-4d, and A-4g.2 are sources of fugitive emissions so only the visible emissions standard applies and the particulate emissions standards (grain loading limits) do not apply. [Permit Conditions 33 and 34]

i.  Testing requirements: Except for emissions units A-3a and B-3c, the permittee is not required to do any testing using reference test methods because the monitoring described below should be sufficient for providing a reasonable assurance of compliance. Monthly VE tests are required for emissions units A-3a and B-3c. For those emissions units that are not required to be tested, the permit identifies the reference test method that would be used in the event that testing is performed for compliance purposes. [Permit Conditions 48 and 100]

ii.  Monitoring requirements: As discussed above, a weekly inspection and maintenance program is used for monitoring emissions units A-2a, A-2b, A-2d, A-4a, A-4b, and A-4f because these all have baghouse controls. Fuel records are used for monitoring emissions units A-2c, A-3a.4, A-3a.5, A-3b.1, and B-3d because it is not likely that there will be any visible emissions while burning natural gas or propane. Monthly Method 9 tests are required for emissions units A-3a and B-3c because these emissions units do have the potential of generating visible emissions. For the fugitive emissions sources (emissions units A-4c, A-4d, and A-4g), the permittee is required to inspect the operations at least weekly to determine if there are any fugitive emissions being generated. If fugitive emissions are observed, the permittee is required to take corrective action. [Permit Conditions 98, 99, 100, and 101]

iii.  Recordkeeping requirement: The permittee is required to maintain records of the weekly inspection and maintenance activities, including any necessary corrective action. The permittee must also maintain records of the visible emissions tests and the type and amount of fuel burned in the emissions units. [Permit Conditions 109.d, 109.l, and 109.o]

PSD REQUIREMENTS (EPA 1977 PSD PERMIT)

13.  The following requirements were established in the prevention of significant deterioration (PSD) permit #PSD-X-77-01 issued by EPA in 1977:

a.  Sulfur dioxide emissions limit. EPA Permit No. PSD-X-77-01 (1977 PSD permit) requires that sulfur dioxide not exceed 19.0 pounds per ton of aluminum produced (lb/TAP) as a monthly and yearly average. [Permit Condition 17]

i.  Testing requirements: Sulfur dioxide emissions tests are required at least once each quarter for each potline using the test methods and procedures approved in NWA’s Air Emissions Testing Quality Assurance Plan. OAR 340-238-0140 requires monthly testing unless the Department approves a reduced testing frequency. NWA requested and the Department approves quarterly testing instead of monthly testing based on the same criteria as used for approving reduced testing frequency for the NESHAP requirements (e.g., the average results of the previous 24 months testing is less than 60% of the standard and no monthly result was greater than 75% of the standard). For sulfur dioxide the average monthly result was 8.57 lb/TAP and 60% of the standard is 11.4 lb/TAP. If the standard is exceeded during a quarterly test, the permittee must begin monthly testing for at least 12 months. If the average for 12 months is less than 60% of the standard and no single month value is greater than 75% of the standard, then the permittee ma

y resume quarterly testing. [Permit Condition 47]

ii.  Monitoring requirements: The permittee is required to continuously monitor control device parameters that are indicators of control device performance. [Permit Condition 70] (See also the discussion of the Compliance Assurance Monitoring requirements.)

iii.  Recordkeeping requirements: The permittee is required to keep records of control device efficiency (emission test results) and control device parameter data. [Permit Conditions 109.m and 109.y]

b.  Primary scrubber parameter limits. The PSD permit issued by EPA established the following wet scrubber parameter limits: [Permit Conditions 26, 27, and 28]

i.  Testing requirements: The scrubber parameters are monitored during each TF, PM, SO₂, and POM performance test. [Permit Condition 47]

ii.  Monitoring requirements: Scrubber recycle rate, pH, and specific gravity are monitored continuously and recorded on a strip chart. NWA checks the readings at least once every 4 hours and a daily average is determined every 24 hours. SO₂ concentrations are determined when the sulfur dioxide tests are performed as discussed in item 13.a above. [Permit Conditions 78 through 81]

iii.  Recordkeeping requirement: Data is recorded on a strip chart and the daily averages are entered into a computer spread sheet. [Permit Condition 109.m]

NESHAP REQUIREMENTS

Subpart A General Provisions

14.  The general provisions of subpart A of 40 CFR Part 63 apply to this source because it is subject to subpart LL for primary aluminum production facilities and subpart RRR for secondary aluminum production facilities. A table showing which requirements of subpart A are applicable is provided below. [Permit Condition 13 and Attachment B]

a.  Testing requirements: Testing is not required because these types of standards do not have emission limits that can be compared to an emissions test result for the purpose of determining compliance.

b.  Monitoring and recordkeeping requirements: The monitoring and recordkeeping requirements for the specific NESHAP standards will be used to determine compliance with the general provisions so no additional monitoring is required.

Subpart LL Requirements

15.  NESHAP requirements that are applicable to the primary aluminum production potlines (40 CFR part 63, subpart LL) are shown in the following table and the testing, monitoring, and recordkeeping reqquirements for the specific emissions limits are discussed after the table. [Permit Conditions 18 through 20, 29, 40 through 45, 52, 75 through 84, 112, 127, and 129 through 137]

a.  NESHAP total fluoride limit. NWA is a vertical stud soderberg (VSS1) primary aluminum production plant, so the total fluoride limit is 2.2 lb/TAP from each potline or 2.0 lb/TAP as an average of the two potlines once the emissions averaging implementation plan is approved by EPA. These limits are specified in 40 CFR 63.843(a)(1)(v) and 63.846(b). [Permit Conditions 18 and 20]

i.  Testing requirements: Total fluoride emissions testing requirements are specified in 40 CFR 63.847(b)-(e), 63.848(a)&(e), and 63.849. Many of these requirements also refer to the general testing requirements in section 63.9 of subpart A. In summary, the permittee is required to perform an initial performance test within one month after the compliance date (10/7/99) and continue to test the primary control system every year (three test runs/year) and secondary control system monthly (three test runs/month/potline). Since there are 40 secondary roof scrubbers (20 per potline), two scrubbers on each potline are tested each month so that all of the scrubbers will be tested during the year. The monthly emissions are determined from the most recent tests performed on the secondary scrubber (three runs with at least one run done before the 15^th and one run done after the 15^th of the month) and added to the average of all tests performed on the primary control system during the previous 12-month period. The testing is to be performed in accordance with the reference test methods specified in the regulations or alternatives approved by the EPA as specified in the test plan and Northwest Aluminum’s Air Emissions Testing Quality Assurance Plan. The testing on the secondary scrubber system may be reduced to quarterly if approved by the EPA. Based on the information provided in the Title V permit renewal application, the Department agrees with the proposed reduced testing frequency. The average of all tests performed during a 24-month period immediately preceding the date the application was submitted was less than 60% of the applicable limit and there were no

monthly averages greater than 75% of the applicable limit. Since a single primary control system is used to control emissions from both potlines, it is not possible to determine emissions from the potlines separately, so Northwest Aluminum has no alternative but to use the emissions averaging procedures to demonstrate compliance with the emissions averaging limit. [Permit Condition 51]

ii.  Monitoring requirements: The permittee is required to continuously monitor control device parameters that are indicators of control device performance and take corrective action any time that there is an exceedance of the parameter limits. The monitoring requirements are specified in 40 CFR 63.847(h), 63.848(a), (e), (f) through (l) along with the general monitor requirements in subpart A. The permittee has identified control device parameter limits based on historical data. [Permit Conditions 76 through 84] (Note that the NESHAP monitoring requirements are also used to partly satisfy the CAM requirements for particulate matter and sulfur dioxide. See the discussion of the Compliance Assurance Monitoring requirements later in this section.)

iii.  Recordkeeping requirements: The permittee is required to keep records of emissions test results, control device parameter data, and corrective action when a control device parameter is exceeded along with the general monitoring records required by subpart A. [Conditions 112 through 114]

b.  NESHAP polycyclic organic matter (POM) limit. NWA is a vertical stud soderberg (VSS1) primary aluminum production plant, so the POM limit is 2.4 lb/TAP from each potline or 2.1 lb/TAP as an average of the two potlines once the emissions averaging implementation plan is approved by EPA. These limits are specified in 40 CFR 63.843(a)(1)(v) and 63.846(b). [Conditions 19 and 20]

Testing requirements: POM emissions testing requirements are specified in 40 CFR 63.847(b)-(e), 63.848(b)&(e), and 63.849. Many of these requirements also refer to the general testing requirements in subpart A. In summary, the permittee is required to perform an initial performance test within one month after the compliance date (10/7/99) and continue to test the primary control system every year (three test runs/year) and secondary control system quarterly (one test run/month/potline). Since there are 40 secondary roof scrubbers (20 per potline), two scrubbers on each potline are tested each month so that all of the scrubbers will be tested during the year. The quarterly emissions are determined from the most recent tests performed on the secondary scrubber (three runs) and added to the average emissions from the three most recent tests performed on the primary control system. The testing is to be performed in accordance with the reference test methods specified in the regulations or alternatives approved by the EPA as specified in the test plan and Northwest Aluminum’s Air Emissions Testing Quality Assurance Plan. Since a single primary control system is used to control emissions from both potlines, it is not possible to determine emissions from the potlines separately, so Northwest Aluminum has no alternative but to use the emissions averaging procedures to demonstrate compliance with the emissions averaging limit. [Permit Condition 51]

i.  Monitoring requirements: The permittee is required to continuously monitor control device parameters that are indicators of control device performance and take corrective action any time that there is an exceedance of the parameter limits. The monitoring requirements are specified in 40 CFR 63.847(h), 63.848(a), (e), (f) through (l) along with the general monitor requirements in subpart A. The permittee has identified control device parameter limits based on historical data. [Permit Conditions 76 through 84] (Note that the NESHAP monitoring requirements are also used to partly satisfy the CAM requirements. See the discussion of the Compliance Assurance Monitoring requirements later in this section.)

ii.  Recordkeeping requirements: The permittee is required to keep records of emissions test results, control device parameter data, and corrective action when a control device parameter is exceeded along with the general monitoring records required by subpart A. [Conditions 116 through 114]

c.  Capture and control of paste production plant emissions. The permittee is required to capture and control the paste production plant emissions with a dry coke scrubber to reduce POM emissions in accordance with 40 CFR 63.843(b)(1) and (2). [Permit Condition 29]

i.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emission test result for the purpose of determining compliance.

ii.  Monitoring requirements: The permittee is required to continuously monitor the dry coke scrubber coke flow and air flow in accordance with 40 CFR 63.848(f) and take corrective action whenever the parameter limits are exceeded. In addition, the permitte is required to perform daily visible emission monitoring by inspecting the control device exhaust for evidence of any visible emissions indicating abnormal operations as specified in 40 CFR 63.848(g). [Permit Conditions 79 through 81, and 83]

iii.  Recordkeeping requirement: The permittee is required to maintain records of control device parameter data, exceedances of parameter limits, visible emissions that indicate abnormal operations, and corrective action, if necessary. These records are required by 40 CFR 63.850(e)(4). [Permit Conditions 112 through 114]

d.  Startup, shutdown, malfunction plan. NWA is required to prepare and implement a startup, shutdown, malfunction (SSM) plan for the primary aluminum production facility. However, according to 40 CFR §63.850(c), the plan does not have to be submitted with the application for a permit nor does it have to be included in the permit. The Department will verify that an SSM plan has been developed and is being implemented during annual inspections. [Permit Conditions 42]

e.  Site-specific test plan. On August 3, 1999, NWA submitted a test plan along with a proposed test schedule to EPA and the Department. The Department has reviewed the plan and determined that it satisfies the requirements of 40 CFR Part 63. There are some minor variations to the test methods, but they are not considered significant changes. However, the Department does not have final approval authority since EPA has not delegated authority for the NESHAP. Therefore, EPA will have to review and approve the plan. The Department will assume that EPA approves the test plan if they have no objections to issuing the permit. [Permit Condition 51]

Subpart RRR Requirements

16.  NWA must comply with the applicable requirements of 40 CFR part 63, subpart RRR by March 24, 2003. A summary of the applicability determinations for subpart RRR requirements is provided below: [Permit Conditions 35, 36, 40 through 45, 52 through 59, 85 through 97, 110, 111, 113, 121 through 126, 128, and 129 through 137]

a.  Site-specific test plan. NWA is required to submit a site-specific test plan.

b.  SSM plan. In accordance with 40 CFR §63.1NWA is required to develop and implement an SSM plan for the secondary aluminum production facility.

c.  OM&M plan. In accordance with 40 CFR §63.1506(a) and §63.1510(b), NWA is required to develop and implement an Operation, Monitoring, and Maintenance (OM&M).

Note: All of the plans specified above have been completed.

OTHER FEDERAL REQUIREMENTS

17.  New Source Performance Standards (NSPS). None of the NSPS (40 CFR Part 60) are applicable to this facility either because the facility is not within the source category regulated by the standard or does not have emissions units regulated by the standard. The standards of performance for primary aluminum reduction plants (Subpart S) are not applicable because this facility began operations before October 23, 1974. Although there are no specific standards that apply to the facility, the general provisions (subpart A) and appendices to Part 60 (test methods) may be applicable or become applicable during the permit term, so they are not listed in the nonapplicable requirements section of the permit.

18.  National Emissions Standards for Hazardous Air Pollutants (NESHAP). With the exception of Subpart M (asbestos standards), none of the NESHAPs in 40 CFR Part 61 are applicable to this facility because the facility is not within the source categories regulated by the standards. However, just as with the NSPS, the general provisions (subpart A) and appendices may be applicable or become applicable during the permit term. With the exception of subparts A (general provisions), LL (primary aluminum reduction plants) and RRR (secondary aluminum production facilities), none of the NESHAPs in 40 CFR Part 63 are applicable to this facility because the facility is not within the source categories regulated by the standards. The applicable provisions of 40 CFR part 63, subparts A, LL, and RRR have been discussed above.

19.  Compliance Assurance Monitoring (40 CFR part 64). As part of the permit renewal application, NWA submitted a compliance assuring monitoring (CAM) plan in accordance with OAR 340-212-0200 through 340-212-0280 and 40 CFR part 64 for the primary aluminum production line (emissions unit A-1). All other emissions units at the facility were determined to not be subject to CAM because they either do not have control devices, or the pre-control potential emissions are less than 100 tons per year for affected pollutants, or the emissions unit is subject to 40 CFR part 63. The plan was evaluated by the Department and approved. Key elements of the plan for monitoring the performance of the pollution control devices (primary dry alumina baghouse, primary wet SO₂ scrubber, and secondary roof vent wet scrubbers) have been incorporated into the permit as attachment C, which includes the indicator of performance, indicator range, data collection method and frequency, and quality assurance procedures. [Permit Conditions 47, 78 through 82, and 84]

20.  Accidental Release and Prevention (40 CFR part 68). The accidental release prevention regulations in 40 CFR Part 68 did apply to this facility because chorine was used in processes at levels greater than the threshold levels. The use of chlorine has been discontinued, so the 40 CFR Part 68 no longer applies. However, the requirement is still included in the permit in the event that regulated materials are used in the future. [Permit Conditions12]

21.  Stratospheric ozone standards (40 CFR part 82). Halon 1301 is used in the fire suppression system. The fire suppression system is serviced once per year by an outside contractor. The production of halon was discontinued on 10/01/94. Use of halon is not regulated and can continue until supplies are depleted. The use of 1,1,1-trichoroethane as a part cleaning solvent has been discontinued.

a.  Servicing of motor vehicle air conditioners (mvac). Subpart B of 40 CFR Part 82 is applicable to NWA because servicing of motor vehicle air conditioners is performed at the site. Each service person is required to maintain a certification for performing service on mvac. [Permit Condition 11

b.  Testing requirements: Testing is not required because this type of standard does not have an emission limit that can be compared to an emissions test result for the purpose of determining compliance.

c.  Monitoring and recordkeeping requirements: The permittee is required to maintain records of certifications. [Permit Condition 69 and 109.z]

INSIGNIFICANT EMISSIONS UNITS

22.  As identified earlier in this Review Report, this facility has insignificant emissions units (IEUs) that include categorically insignificant activities and aggregate insignificant emissions, as defined in OAR 340-200-0020. For the most part, the standards that apply to IEUs are for opacity (20% limit) and particulate matter (0.1 gr/dscf limit). The Department does not consider it likely that IEUs could exceed an applicable emissions limit or standard because IEUs are generally equipment or activities that do not have any emission controls (e.g., small natural gas fired space heaters) and do not typically have visible emissions. Since there are no controls, no visible emissions, and the emissions are less than one ton per year, the Department does not believe that monitoring, recordkeeping, or reporting is necessary for assuring compliance with the standards. According to the application, none of the IEUs are subject to a NESHAP or NSPS. [Permit Condition 37

]

PLANT SITE EMISSION LIMITS

23.  The baseline emissions rate, netting baseline, and PSEL information is summarized in the following table: [Permit Condition 38]

a.  Definitions for the terms used in the PSEL summary table are provided at the end of this review report.

COMPONENTS OF THE NETTING BASIS

24.  Components of the Netting Basis are shown in the following table:

a.  The current potential emissions for CO and fluoride are less than the PSEL, which is based on the current capacity of the plant.. The excess emissions are classified as unassigned emissions in accordance with OAR 340-222-0045.

b.  Unassigned emissions may be used for internal netting to allow an emission increase at the existing source in accordance with the permit.

c.  Unassigned emissions may not be banked or transferred to another source.

d.  Emissions that are removed from the netting basis are unavailable for netting in any future permit actions.

e.  Unassigned emissions will be reduced to not more that the significant emission rate on July 1, 2007.

f.  NWA must notify the Department of any changes at the facility that would utilize the unassigned emissions in accordance with OAR 340-218-0190.

SIGNIFICANT EMISSION RATE

25.  The proposed PSEL is greater than the previous netting baseline for PM₁₀, NO_x, and VOC as shown below. The proposed PSEL is not greater than the previous netting baseline for SO₂ and Fluoride. Since the requested increases are less than the significant emissions rate for the pollutants, the increases have been approved without further analysis in accordance with OAR 340-222-0040(1)(a)(A).

HAZARDOUS AIR POLLUTANTS

26.  NWA has estimated potential hazardous air pollutant emissions as follows. Since the total HAP emissions are greater than 25 tons per year, this facility is a major source of hazardous air pollutants.

a.  Emissions factor derived from source test data.

b.  Emission factor from AP-42, section 7.8.

c.  Emission factor from Air Chief, Version 3

d.  Emission factor equals regulatory limit (40 CFR part 63, subpart LL).

27.  Hazardous air pollutant PSELs are established in the permit for POM and Carbonyl sulfide for fee purposes, since these pollutants are not included in the particulate matter or volatile organic compound PSELs. Hydrogen fluoride (gaseous fluoride) emissions are included in the fluoride PSEL; formaldehyde emissions are included in the VOC PSEL; mercury emissions are included in the particulate matter PSEL; and naphthalene emissions are include in the POM PSEL. [Permit Condition 39]

28.  The following toxic substances are used at NWA in the approximate quantities listed below:

GENERAL BACKGROUND INFORMATION

29.  The proposed permit is a renewal of an existing Oregon Title V Operating Permit that was issued on 07/01/2001. The existing permit was scheduled to expire on 05/01/06 but remains in effect until this permit is issued.

30.  Other permits issued or required by the Department for this source include a NPDES permit (NPDES 0001708). NWA is also registered with the Department as a large quantity hazardous waste generator (ORD 981764707).

31.  This source is located in an area that is designated as in attainment with all National Ambient Air Quality Standards (NAAQS).

32.  This source is located within 200 kilometers of the Mount Hood and Mount Adams Wilderness Areas, which are Class I air quality protection areas. The source is also located in the Columbia River Gorge National Scenic Area.

COMPLIANCE HISTORY

33.  During the last permit term, the facility was inspected on 9/12/01, 9/24/03, and 7/6/05 and found to be in compliance with permit conditions.

34.  On August 21, 2003, Department personnel observed visible emissions coming from the primary casthouse in excess of 20% opacity. Notice of Noncompliance #AQ-ERB-01-10645 was issued on August 28, 2003. NWA responded on September 22, 2003 with an explanation that the excess emissions probably occurred due to a malfunction in the fluxing sequence. The system was modified by automating the fluxing sequence to prevent future malfunctions.

35.  During the last permit term, the Department’s Water Quality section issued two Notices of Noncompliance for exceeding effluent limits for cyanide. NWA immediately corrected the problems.

SOURCE TEST RESULTS

36.  NWA conducts routine testing of the primary and secondary control systems on the potlines for particulate matter, fluoride, and sulfur dioxide emissions. The results of the emissions testing are submitted to the Department monthly.

37.  NESHAP test results: An initial compliance test for the Secondary Aluminum NESHAP was conducted on Furnace A-3a.1 (a group 1 furnace) and B-3c.1 (a group 2 furnace). The results are summarized below:

PUBLIC NOTICE

This permit was placed on public notice from April 21 to May 25, 2006. There were no comments submitted in response to the public notice. The Department requested and EPA agreed to an expedited review of 5 days since there were no substantive or adverse comments during the comment period. In any event, the public will have 105 days (45 day EPA review period plus 60 days) from the date the proposed permit is sent to EPA to appeal the permit with EPA.

EMISSIONS DETAIL SHEETS

The basis for the plant site emissions limits and baseline emission rates are provided in the attached emission detail sheets. In general, the emissions are based on actual test data and projected maximum production rates. The definition of terms used in the this review report and the emissions detail sheets is provided below.

Plant Site Emissions Limit Table:

Pollutant: Plant site emission limits shall be established for all regulated pollutants listed in Table 2 of OAR 340-218-0020 . In limited situations, a PSEL may be established for a hazardous air pollutant for the purposes of paying fees (voluntary request by the permittee) or the source is subject to a hazardous air pollutant emission standard, limitation, or control requirement other than the PSEL. Other pollutant mass emission limits may be established, but these should be considered performance standards and not PSELs. For example, during the initial permitting of a fiberglass facility, the Department may establish a mass emissions limit specifically for styrene. This limit should not be considered a PSEL because there is no ambient air quality, NSPS, or Part 61 NESHAPstandard for styrene, but the styrene would be included in the PSEL for VOC. Another example would be if the Department believes it is necessary to establish an ammonia emission limit for a combustion device utilizing ammonia injection for control of NO_x. The ammonia limit should not be a PSEL because there is no ambient air quality standard for ammonia. Lead is one hazardous air pollutant for which it may be necessary to establish a PSEL because there is an ambient air quality standard for lead. However, it is not included in the table above because most sources do not emit lead. It would have to be added for the sources that do emit lead.

The baseline emission rate equals the actual pollutant emissions during the baseline period of 1977 or 1978. An earlier year may be used if neither 1977 nor 1978 are representative of normal operations. (Note: Each source should have already identified an appropriate baseline period, so only in very rare cases will the Department approve an alternative year.) Once established, the baseline emission rate never changes, except that it may be corrected when better information about the actual emissions during the baseline period becomes available (e.g., source test data). For new sources (those that were installed after 1978), the baseline emission rate is zero for all pollutants. [OAR 340-218-0020] If a current source operated in the baseline period, and continuously since that time, the source has a baseline emission rate whether or not it is permitted. However, a source that permanently shut down and then started up again after the baseline period would have a baseline emission rate equal to zero, even if the source is the original facility and includes the original equipment.

The netting baseline is the baseline for determining net increases as a result of a major modification as defined in OAR 340-218-0020. The netting baseline equals the baseline emission rate or the emissions that were approved during the last NSR action in accordance with OAR 340-224-0010 through 340-224-0110 for only the pollutants subject to NSR. In addition, the netting baseline must be adjusted to reflect any emission reductions required by rule. Both the previous and proposed netting baseline should be shown in the column if it has changed due to the current permit action. If the netting baseline is changed, the review report will also need a complete discussion of the NSR action or reductions due to a new rule. Reductions required by rule will effect the netting baseline at the time the rule is adopted, which could occur at any time during the permit term. The previous netting baseline would be adjusted at the next permit renewal.

The previous PSEL is the PSEL approved in the previous permit. In some cases, the previous PSEL will need to be corrected if new emissions information becomes available. If there are corrections, they should be explained in the review report. The previous PSEL is provided to show whether there are any proposed PSEL increases.

The proposed PSEL is the PSEL requested by the permittee and approved by the Department. The PSEL shall equal the baseline emission rate and be adjusted upward or downward in accordance with OAR 340-222-0040. Since the PSEL cannot include emission reductions required by a rule, the PSEL is equal to the netting baseline plus any past or present requested increases approved by the Department. Requested increases are evaluated as follows:

1.  If the requested increase is due to utilizing existing capacity that also existed during the baseline period(e.g., the increase is not due to a physical modification and it is not due to, or associated with, capacity that was installed after the baseline period), the permittee shall demonstrate a need and:

a.  Demonstrate that the requested increase above the netting baseline is less than the significant emission rate (SER); or

b.  If greater than or equal to the SER, provide an assessment of the air quality impact showing that no ambient air quality standard or PSD increment will be violated in an attainment area or an offset has been obtained in a nonattainment area.

2.  If the requested increase is due to a proposed physical modification or change in the method of operation (e.g., de-bottle necking that would increase the capacity of the facility), the permittee shall:

a.  Demonstrate that the net emission increase above the netting baseline is less than the significant emission rate (SER) in accordance with OAR 340-200-0020; or

b.  If greater than or equal to the SER, satisfy the requirements of the NSR rules [OAR 340-224-0010 through 340-224-0110].

3.  If the requested increase is due to both utilizing existing capacity and a physical modification, the increases shall be tracked separately as shown in the significant emissions rate table. If the total increase is greater than the SER, but the increase due to a physical modification is less than the SER, the source shall satisfy the requirements of item 1 above.

4.  PSELs shall not be established which allow emissions in excess of those allowed by any applicable federal or state regulation in accordance with OAR 340-222-0040(7). Note that reductions required by rule do not affect the baseline emission rate, but they will affect the netting baseline.

PSEL increase means the difference between the proposed PSEL and the previous PSEL. This can be a positive or negative number. This information is primarily for the purpose of keeping the public informed of any recent changes in the allowable emissions of a source. The information is not used to determine if an SER has been exceeded. SER exceedances are determined as the difference between the proposed PSEL and the netting baseline.

PTE (potential to emit) means the maximum capacity of a stationary source to emit any air pollutant under its physical and operational design in accordance with OAR 340-200-0020. Any physical or operational limitation on the capacity of a source to emit an air pollutant, including air pollution control equipment and restrictions on hours of operation or on the type or amount of material combusted stored, or processed, shall be treated as part of its design if the limitation is enforceable by the Department. PTE is used to determine which type of permit is required. If the PTE is less than the major source threshold levels, the source would be required to obtain an ACDP, which may or may not include synthetic minor conditions. If the PTE is greater than the major source threshold levels, the source would be required to obtain an Oregon Title V Air Operating Permit.

It is not expected that the PTE will be determined for every source. If the PSEL and the PTE are clearly greater than the major source threshold levels, there is no need to go through the exercise of calculating the PTE. However, it is important to show the PTE for two specific situations. The first would be when the PTE is less than the major source threshold levels for all pollutants, but the PSEL is greater than 100 tons for one or more pollutants (remember, PSELs are not normally established for HAPs). In this case, the source is not subject to Title V permitting. The second situation is when the PTE is greater than the major source threshold levels for one or more pollutants, but the PSEL is less than 100 tons for all non-HAP pollutants. In this case, the source is subject to Title V permitting.

The PTE does not affect the PSEL and the PSEL shall not be reduced solely because of the PTE. However, it is not expected that any previous action that decreased PSELs to equal the PTE be reversed.

Components of the PSEL Table:

The assigned PSEL is that portion of the PSEL that is not a credit or unassigned PSEL, as discussed below. This should equal the projected emissions shown on the emissions details sheets submitted with the permit application. This is also the place where the short term PSEL can be shown. The units of the short term PSEL will have to be identified.

The unassigned PSEL is that portion of the PSEL that is greater than the source’s current demonstrated need to emit, excluding any credits. The source’s current demonstrated need to emit may be thought of as the source’s potential emissions given the actual operating schedule and physical configuration of the facility. The unassigned PSEL would at least equal the difference between the proposed PSEL and the PTE (less any credits), if the PTE is less than the PSEL as identified in the table above. However, in some cases, the unassigned PSEL may be even greater if, for example, the source’s operating schedule is dramatically less than during the baseline period. Other reasons for declaring some of the PSEL as unassigned are to avoid paying Title V fees or to show the difference between actual potential emissions and allowable emissions.

Credits are established by OAR 340-268-0030 and 340-268-0040. Credits are a portion of the total PSEL and should, therefore, not exceed the PSEL. Credits need to be identified separately in the permit with the terms (e.g., expiration date) of the credit clearly stated. Note, the baseline emission rate is not affected by credits and the PTE of a source would, by definition, not include any credits, whether transferred or banked.

Emission reduction credits, whether from shutdowns, curtailments, or over-control, are available for external offsets for a period of two years from the date of the actual emissions reduction in accordance with OAR 340-268-0040(5). Emission reduction credits as a result of over-control may also be banked for a specified period up to ten years in accordance with OAR 340-268-0030(2). Requests for emission reduction credit banking shall be submitted to the Department prior to or within one year following the actual emissions reduction. [OAR 340-268-0030(8)] Emission reduction credits due to shutdowns or curtailments may not be banked. [OAR 340-268-0030(4)]

If credits are not used as external offsets within the time period allowed, the terms of the credit expire and the credits are transferred over into the permittee’s unassigned PSEL of the permit for internal netting purposes only. If credits, whether banked or not, are transferred for external offsets, the PSEL is reduced by an amount equal to the offset and the netting baseline is reduced by an equal amount. External transfers of credits are permanent; once the PSEL and netting baseline are reduced to reflect a transferred credit they will not be restored even if the new source is never built.

While this portion of the guidance is consistent with current Department policy, it is not expected that any previous action that removed unused credits from the PSEL be reversed. From this time forward, or until such time that the PSEL rules are changed, credits not used for external offsets remain as part of the PSEL.

Significant Emission Rate Table:

The SER (significant emission rate) for each pollutant is defined in OAR 340-200-0020. Pollutant emission increases above the SER are subject to additional requirements. For PSEL increases that do not involve a physical modification, an air quality assessment is required to show that there will not be a violation of an ambient air quality standard or PSD increment. For PSEL increases that are the result of a physical modification, the permittee shall comply with the NSR requirements in OAR 340-224-0010 through 340-224-0110.

The requested increase is the difference between the proposed PSEL and the previous netting baseline less any credits and reductions required by rule since the last permit action. The requested increase is also divided into portions that are due to utilization of capacity that existed in the baseline period and/or physical modifications at the facility as discussed in the Proposed PSEL section above. If the requested increase is greater than the SER, the review report will have to include a discussion of why the Department is approving the increase. This could be the results of an air quality assessment or NSR review, depending on the reason for the increase.