### Support Document

For the Air Operating Permit Issued to

Alcoa Wenatchee Works 6200 Malaga/Alcoa Hwy Malaga, WA 98828-9728

by

State of Washington Department of Ecology

300 Desmond Drive

P.O. Box 47600 Olympia, WA 98504-7600

Page 1 of 25 March 2010

### Table of Contents

INTRODUCTION

FACILITY AND PROCESS DESCRIPTIONS 3

3

PERIODIC MONITORING 6

SPECIFIC PERMIT CONDITIONS 7

A) Aluminum Plant Emi ssion Standards 7

B) Plant Wide Operati on and Maintenance 7

C) Opacity Permit Conditions 8

D) Compliance with Particulate Matter Requirements 9

E) SO2 Permit Conditions 12

F) Ambient and Forage Fluoride Conditions 13

G) Other parameters not required by MACT

H) Potroom Operation and Maintenance 14

I) MACT 15

J) IEUs 17

K) Corrective Action 17

L) Best Available Retrofit Technology (BART) 18

M) Greenhouse Gas

APPENDIX A ORDERS 20

APPENDIX B EMISSION UNIT NUMBERS 21

A PPENDIX C DATA TABLES 25

Page 2 of 25 March 2010

### Introduction

This document, the support document, summar izes the legal and factual basis for the permit conditions in the ai r operating permit issued by the Washington State Department of Ecology to the source. Unlik e the air operating permit, this document is not legally enforceable. This support document summarizes the emitting processes at the facility, air emissions, permitting and compliance history, the statutory or regulatory provisions that re late to the facility, and the steps taken to provide opportunities for public review of the perm it. The Permittee is obligated to follow the terms of the permit. Any errors or om issions in the summaries provided here do not excuse the Permittee from the requirements of the permit. This Operating Permit Support Document fulfills the operating permit rule “Stateme nt of Basis” requirement and explains particular porti ons of the air operating perm it for Alcoa Wenatchee Works, a primary aluminum smelter, located near Malaga, WA.

This document is not part of the air operating permit for Alcoa Wenatchee Works. Nothing in this document is enforceable agai nst the permittee, unless otherwise made enforceable by pe rmit or order.



### Facility and Process Descriptions

Alcoa, Wenatchee Works is located in Wenatche e, Washington. This facility is capable of producing 243,000 tons per y ear of primary aluminum th at is sold as aluminum foundry ingot, pig or sow. In July of 2001, the smelter was temporarily curtailed due in part to high electrical energy costs.

The process of aluminum redu ction requires the electrolytic decomposition of alumina into two chemical components (Hall-Herou lt process) which are metallic aluminum and gaseous oxygen. In or der to accomplish this, alumina must be brought into a liquid phase allowing electrical direct current to pass through it. The pr ocess uses cryolite, a fluorinated compound of sodium and alumi num, which melts at approximately 1000 o C. Cryolite has the capability, in th e molten state, to hold up to 8% alum ina in solution. Molten aluminum, which is released during the electrolys is, has a slightly higher specific gravity than molten cryolite at the cell operating temperature, and therefore settles to the bottom of the cell forming a molt en aluminum metal pad. The electrolytic cell consists of a steel shell lined with insulating materials and having an electrically conductive bottom made of carbon connected to the negative pola rity of the power sour ce. Suspended from above and immersed into the cryolite-alumina melt are carbon anodes connected to the positive side of the electric cell. When the electric current flows from the anode to the cathode, alumina is split into metallic aluminum which spreads over the cell bottom and into oxygen which evolves at the inner su rface of the carbon anode. The oxygen burns and thereby releases a blend of gasses, pr imarily carbon dioxide, carbon monoxide, and

Page 3 of 25 March 2010some sulfur dioxide. Th e generation of sulfur dioxide is due to the sulfur content of the anode material. Hydrogen fluo ride also evolves from the cr yolite bath due to the high operating temperatures of the cells and th e presence of moistu re in the alumina.

For the production of aluminum, there are four basic cell designs. Two are designated as “prebake” and two as “Soderberg”. The Al coa, Inc. smelter at Wenatchee operates center-worked prebake (CWPB) cells. Prebak e cells utilize carbon anodes, made from petroleum coke and coal tar pitch, which have been pre-fo rmed into blocks, baked, and secured onto copper rods prio r to being introduc ed into a cell. Pressing, baking and rodding take place on-site in the green carbon, carbon bakin g, and anode rodding processes respectively. In cen ter-worked pots, the crust overlying the molten bath is broken and ore is fed by mean s of a puncher-feeder device located along the cell’s
centerline between the two ro ws of anodes. The indivi dual cells are arranged in “potlines” which are rows of cells connected electrically in series.

Air pollution control systems employed at Alcoa include the following:

For potlines, primar y emission control systems capt ure pot fumes. The systems consist of hoods and movable shields around each pot, and a system of ducts and fans which draw the fume from each pot to a centralized treat ment system. The treatment system consists of two types of alumina dry scrubbers (referred to as
either A-398 fluidi zed bed or alumina injection system) which use alumina to react with and remove hydrogen fluoride in the gas stream . The resulting aluminum fluoride is removed, along with ot her particulate matter , by a system of fabric filter containing ba ghouses prior to venting the treated gasses to the atmosphere. The aluminum fluoride particulate is recycled in the potroom

process.
For anode bake ovens, a dry alumina scrubber system, with fluidized bed alumina reactors and baghouses (A-446), treats bake oven gasses in a fashion similar to the A-398 system described above. Bake ove n gasses consist of combustion products from natural gas and from vo latile matter that is driven off the baking anodes and burned in the ovens, partic ulate matter from the pack ing coke surrounding the baking anodes, and fluoride present in spent anodes (a nodes removed from the pot
cells are crushed and returned to the anode mix). The al umina used in the scrubber is recycled as feedstock in the potrooms.

For the green mill, a dry coke injection scrubber system (Procedair) is used for collecting and treating organic vapors and particulates in the carbon plant. In the green mill, petroleum coke and coal tar pitch are heated, mixed and pressed
into anodes. Carbon particles and organic va pors are generated by these processes. The coke scrubber adso rbs volatile material onto calcined petroleum coke which is in jected into the ductwork a nd waste gas streams, and a baghouse captures the resulting particles. The coke fines and adsorbed organic

Page 4 of 25 March 2010vapors collected by the baghouse are recycled back into the anode forming

process.
Numerous ancillary processe s in the plant are equippe d with dust collectors.

In addition to physical control systems, operating practices and maintenance are important factors in emissions, especially in the potrooms, where pollutants not captured by the primary emission system are released without treatment through
roof vents 

### Compliance Performance

The potroom, anode baking and green mill gas treatment systems are all in compliance with and meet the Primary MACT an d applicable state requirements.

There have been two non-comp liances with the AOP up to the date of this renewal
submission.

In a letter dated February 2, 2007 Ecology issued a Notice of Violation to Alcoa based on monthly air reports submit ted by Wenatchee Works. The following excursions
where noted:

Date AOP
Unit Parameter Limit Measured Basis of Limit

2005,

4 th
Quarter D.5 Particulate 0.005 gr/dscf 0.0075 gr/dscf Order 02AQIS-3459
and AOP 000068-0

2006,

2 nd
Quarter D.5 Particulate 0.005 gr/dscf 0.0064 gr/dscf Order 02AQIS-3459
and AOP 000068-0

Alcoa subsequently submitted two WAC 173- 400-107 reports claimi ng that the excess
emissions where unavoidable and could not have been pr evented through carefully planning or improved design. Ecology accept ed that the first inst ance met the burden of proof based on the fact that the potline had recently been starte d from an absolutely cold condition, and that initial emissions can be higher than during normal operations. The second instance (2006, 2 nd quarter) was determined to have not met the burden of proof and a fine of $22,750 wa s assessed and paid by Alcoa. The cau se of the second
exceedance was determined to be due to an increase in th e fineness of al umina shipped
to Wenatchee. To reduce emissions Wena tchee conducted a comp lete bag changeout with finer mesh bags (cos t over $250,000) and adjusted pulse ra tes accordingly. Emissions have consistently been less than half the limit since the second exceedance

Page 5 of 25 March 2010On January 23 rd , 2007 Alcoa exceeded their parametr ic limit for salt addition to a melting furnace. Parametric limits ar e set under Secondary Aluminum MACT (40 CFR Part 63 Subpart RRR) and Condition G .9 of the permit. The excess salt was
calculated to have NOT cause an exceedance of an emission s limit. This parametric exceedance was reported to Ecology by phone, in the next monthly air emissions report, and in the ne xt semi-annual Secondary Alumi num MACT report. The cause
was determined to be operator error, and new procedural controls were instituted.
There has not been a reoccurance of this incident.



### Periodic Monitoring

EPA periodic monitoring guidanc e lists the following factors to be considered in arriving at appropriate periodic monitoring methodol ogy. These factors were considered when monitoring, recordkeep ing or reporting requirements were not specified in the underlying applicab le requirement.

1. Likelihood of violating the applic able requirement (i.e. margin of compliance): When considering this criterion, Ecology evaluated available source test data (Appendix C) and the oper ation and maintenance procedures currently in place at the Alcoa Wenatchee Works. When the unit consistently performs well below the standard and the facility has a good O & M history, periodic monitoring may be less frequent or ma y rely on preventative measures (see functional integrity discussion in B) below.

2. Necessity of add-on controls for th e unit to meet the emission limit: This
criterion allows for the consideration of relative risk in the determination of appropriate periodic monitoring. Those sources that present the largest risk
to the environment in the event of a failu re of add-on controls, require frequent source testing as well as continuous evaluation of surrogate performance measures and O & M measures. Also considered are the presence of precedures or processes that shut down the unit if the control systems are not operating

3. Variability of emissions from the unit over time: Units which perform consistently require less frequent source testing th an those where emissions vary widely

4. The type of monitoring, process, ma intenance, or control equipment data already available for the emission unit: Careful consideration is given to the type of control device in use and the demonstrated ability of the company to operate and maintain the device e ffectively. Control devices such as baghouses can be monitored visually and still provide a high degree of certainty that the unit is functioni ng appropriately. Therefore source testing can be done less frequently if the company has a history of compliance

Page 6 of 25 March 2010with operation and maintenance requirements. The addition of functional integrity inspections for all units covere d by the AOP requires weekly visual checks of the control equipment and follow-up corrective action whenever visible emissions, leaks in the duct work, excess vibration, inappropriate pressure drop are observed. This requirement focuses on early detection and prevention of problems

5. Technical and economic considerations as sociated with the range of possible monitoring methods: Ecology considered the cost versus the benefit of source testing, including, for many sour ces, the cost of installation of access ports. For a number of small baghouses at the Alcoa Wenatchee Works, the following cost factors weighed agains t the inclusion of periodic source testing;

• Routine source testing and installation of access to these units would cost an estimated total of more than $600,000 over the 5-year permit.

• Source testing produces very few compliance data points; inspection/correction and parametric monitoring assure much closer attention and yield much more frequent and useful data.

• For very small units, the added cost of this source testing is not justified when compared to the relative envir onmental risk if th e unit is actually not meeting standards. For the largest units, where the environmental risk of not meeting the standard is much larger (in terms of mass or concentration), periodic stack testing is required.

• Once the technology is installed, good O & M becomes the most crucial component of ongoing compliance with the limits.

• Even without routine source testi ng, Ecology retains the authority to require source testing on a case-by-case basis.



### Comments on Specific Permit Conditions

A) Aluminum Plant Emission Standards:

All aluminum plants are required to meet the emission standards of WAC 173-
415-030 and -060. WAC 173-4 15-030 states that “spe cific emission standards listed in this chapter will take preceden ce over the general emission standards of chapter 173-400 WAC. The requirements of C ondition I.1 for visible emissions, Condition I.3 for fugitive emission s and Conditions I.6 and I.7 for SO 2 , take precedence over the requ irements of WAC 173-4 00-040(1), WAC 173-400-- 040(3)(a) and WA C 173-400-040(6), respectively.

B) Facility Wide Requirement Number I.11. Plant-wide Operation and
Maintenance:

Page 7 of 25 March 2010WAC 173-415-030(6) requires alumin um plants to maintain the fac ility and operate and maintain air pollution contro l equipment consistent with good air pollution control practice. Determination of whether acceptable operating and maintenance procedures are being used will be based on information such as, but not limited to, monitoring resu lts, the presence of visible emissions, review of operating and maintenance procedures , and inspection of the source.

Alcoa Wenatchee Works has a systematic operation and maintenance (O & M) program in place that has consistently produced good results, as evidenced by low emissions and satisfactory findings during regulatory inspections. The program consists of inspections of dust collectors in each work area, with inspection records maintained; a preventi ve maintenance program, with records kept; and corrective action initiated promptly.

In addition to these broad O & M requireme nts, this permit includes a requirement to visually inspect all ba ghouses on a weekly basis. This weekly functional integrity inspection includes a check for visible emissions, leaks in ductwork and housing, excessive vibrations, pressure drop, and sight glass readings when available. (Currently, all baghouses co vered by this AOP have had sightglass apparatus installed). In this permit, func tional integrity inspections are used as an indicator of compliance with particulat e limits, opacity and O & M requirements for baghouses. Baghouses th at are properly operated and maintained produce no visible emissions and easily meet a grai n loading standard of 0.005 gr/dscf. Traditionally, O & M compliance has b een demonstrated through observation of
visible emissions and routine maintena nce activities. Weekly inspection and documentation of additional operational c onditions improves the company’s ability to identify and correct problems long befo re an emission standard is violated. Because of this, the company will be require d to invest in corrective action earlier than it would if the permit relied solely on visible em ission observation or stack testing to demonstrate compliance. Corr ective action will be initiated whenever visible emissions (or other fi ndings from the functional integrity inspection, such as significant changes in site glass readings or excess vibration) are observed. Records of inspections and corrective actions will be maintained. In addition, stack tests for particulate matter are also required of the largest baghouses.

Some visible emissions may be obs erved from baghouses during routine cleaning cycles. These emi ssions are of short duration and are not expected to exceed the most stringent opacity lim its. These low intensity short term
emissions are considered to be normal operations and are not subject to the opacity and particulate permit requiremen ts to initiate corrective action when
visible emissions are observed.

Additional potroom operation & maintena nce is described in H) below.

Page 8 of 25 March 2010C) Opacity Permit Conditions:

For dust collector systems with bagh ouses, both the facility-wide O&M and functional integrity inspection requirem ents described above apply. As described above, baghouses which are pr operly maintained easily meet the opacity limits. The requirements for co rrective action when visible emissions are observed are a more effective comp liance strategy than occasional opacity readings. Therefore, no routine opac ity monitoring is proposed, although Ecology retains the ability to require opac ity readings upon re quest. Problems with operating practices are enforceable through the genera l requirement to operate and maintain facilities in a manner consistent with good air pollution control practice and through the functional integrity requirements

For emission units without control devices that may produce visible emissions (e.g. potroom roof vents), routin e opacity readings using th e approved method (EPA Method 9) are impractical due to the conf iguration of the vents, the absense of accessible locations with appropriate viewing angle, and/or effects of weather. Opacity levels from these sources are generally minimal when good operation and maintenance practices are being used. These practices are covered by O & M conditions (see H below) and Alcoa Wenatchee Works has historically operated these sources consistent with good air pollution control practice.

D) Compliance with Particulat e Matter Requirements:

Condition A.5. The particulate emissions from the dry coke scrubber on the green mill are limited to 0.005 gr/dscf. Test re sults show emissions to be 1/10 of the allowable and total less than 1 T/yr. A source test is required once every 5 years and upon Ecology’s request. Ecology determ ined that more fre quent stack testing is not necessary to evaluate compliance based on the margin of compliance, low variability of the test results, and the weekly inspection requirement described in B) above.

Condition A.9. The partic ulate emissions from the coke handling (DC2) dust
collector are limited to 0.1 gr/dscf. Te st results from 2008 were 0.0029 gr/dscf. Ecology assumes that 0.005 gr/dscf is easily achievable and that the unit is in continuous operation. Unde r these assumptions, the unit , while still a very small source, would emit more than 0.75 tons/year (the IEU threshold). In addition, the design of the baghouse is similar to other units where source tests have demonstrated that 0.005 gr/dscf is easily achi evable. A source test is required once every five years and upon Ec ology’s request. Mo re frequent sour ce testing is not necessary due to the small size of th e source, the requirement for weekly inspections and the history of good oper ation and maintenance at the Alcoa

Page 9 of 25 March 2010facility.

Condition B.1. Anode bake oven gasses emitted from the control system are subject to the 0.1 gr/dscf standard contained in WAC 173-400-050 (1). Three source tests are required per year, consistent with the schedule and methods for MACT testing for total fluor ide (TF) and particulate organic matter (POM). Test results show that part iculate emissions are less than 1 % of the limit. Periodic monitoring per B), above, also applies.

Conditions C.1 and C.3. The butt crusher baghouse and the butt blast baghouse are limited to 0.005 gr/dscf. Test results show emissions to be less than 1/10 of the allowable limit and total less than 0.5 T/yr combined if the units are in use 24 hours/day, 7 days/week. No periodic s ource testing is required for these baghouses because of their small size and very low emission rates. Weekly functional integrity inspections are sufficient to demonstrate compliance
with these conditions

Condition C.5. The particulate emissions from the anode cleaning equipment baghouse are limited to 0.005 gr/dscf. Test results show emissions to be 1/10 of
the allowable limit and total less than 1 T/yr. A source test is required once every 5 years and upon Ecology’s request. Ecology determined that more frequent stack testing is not necessary to evaluate compliance based on the margin of compliance, the low variabilit y of the test results, and the weekly inspection requirement described in B) above.

Condition C.8. The partic ulate emissions from the Lectromelt baghouse are limited to 0.005 gr/dscf. Test results show average particulate emissions from this unit are 82% of the standard. Average actual emissions from the Lectromelt baghouse are less than 1 T/year and maximum emissions if the unit is in use 24 hours/day, 7 days/week would be about 1.1 T/ye ar. No periodic source testing is required for this baghouse because it is a small unit, especially when compared to the emissions from the potroom. Weekly functional integrity inspections are sufficient to demonstrate compliance with th is condition.

Condition D.1. Potlin e operations are covered by a pa rticulate matter standard of 15 pounds per ton of aluminum produc ed, found in WAC 173-415-030(2). Compliance is determined by adding particul ate levels determin ed through source tests conducted on the primary control systems to those determined through testing at the potroom roof monitors. Quarte rly source tests ar e conducted for the primary control system. Method 14 equipment has been installed in Rooms 6 and Room 20. These rooms are representative of all potrooms at the facility. Monthly particulate sampling of the roof monitor is conducted in all operating rooms with Method 14 installed. The facility-wide and potroom O&M requirements require

Page 10 of 25 March 2010periodic monitoring. The facility routinely operates well below the 15#/T limit and could not exceed that particulate limit when complying with the TF standard
in Condition D.15. Test re sults for the grain loading standard in the potline 5 primary control system are consisten tly below the 0.005 li mit (60% of the standard at 0.0032)

Condition D.3. The particul ate emissions from the cruce cleani ng facility are limited to 0.005 gr/dscf. Test results show emissions to be less than 1/5 of the allowable, and total less than 1/2 T/yr. A source test is required once every 5 years, and upon Ecology’s request. Ecology de termined that mo re frequent stack testing is not necessary to evaluate compliance based on the margin of compliance, the test results and the weekly inspections described in B) above.

Condition D.5. Particulate emissions from the Potline 5 primary cont rol system baghouse are limited to 0. 005 gr/dscf. Test results show emissions to be consistently less than the standard (averaging 0.0032 gr/dscf). As discussed above in the compliance review se ction, one anomalou s period occurred between late 2005 and early 2006 where more variable and finer alumina supply
resulted in excursions above the limit (0.0075 an d 0.0064 gr/dscf). This problem was robustly corrected with a co mplete changeout and installation of finer mesh bags, and adjust ments in the pulse timing and bag pressure drop.
The most recent 4 quarter average (thr ough June 30, 2008) is 0.0013 gr/dscf, with no single test abov e 0.0016 gr/dscf. Ecology considered the size of the source, the variability of the data and th e margin of compliance and determined that frequent (quarterly) monitoring is ne cessary. Weekly functional integrity inspections are also required

Condition E.1. The partic ulate emissions from the spent potliner (SPL) processing baghouse are limited to 0.005 gr/dscf. Test results show emissions to be about 1/10 of the allowable, and tota l less than 1/2 T/yr. A source test is required once every 5 years, and upon Ec ology’s request. Ecology determined that more frequent stack testing is not n ecessary to evaluate compliance based on the margin of compliance, the test results and the weekly insp ections described in B) above.

Condition F.1. Particulate emissions fr om Boiler 1 and 2 are limited to 0.1 gr/dscf. There are no test results for this unit nor any flow data. Emission estimates are based on natural gas use and EPA published emission factors for
small industrial boil ers (AP-42, Compilation of Air Pollutant Emission Factors). Estimated emissions of 2.4 tons PM/year are conservative and more likely to be about 1T/year because the boilers are used primarily in the wi nter. No source testing is required, however, the permitte e is required to monitor the usage of natural gas and to annually recalculat e emissions using the above mentioned

Page 11 of 25 March 2010emission factors. In addition, the permitt ee must conduct a weekly inspection of
the boiler house.

Condition G.1. Ingo t plant stacks 1, 2, 3, 4, 11 and 12 are li mited to 0.1 gr/dscf.
Test results from Furnace 3 conducted in November 2 005 showed emissions of 0.0508 gr/sdcf with an average 10,454 acfm airflow. Test re sults from Furnace 2 conducted May 2008 show emissions of 0.0155 gr/dscf with an average 6,164
airflow. These test results can be extrapolated to the ot her furnaces since they are all of the same design (fix ed hearth reverbatory furn aces) and are operated the same. Hourly emissions rate s measured during those sa me tests were 2.6 lbs/hr for Furnace 3 (11.4 TPY) an d 0.5 lbs/hr for Fu rnace 2 (2.2 TPY) All testing was
conducted over a full furn ace cycle, which includes charging, melting, skimming, alloying, fluxing and pouring. No source testing is required here since source testing under Secondary MACT requirements (Condition G.3), for particulate, are more stringent. Nevertheless, the permitt ee is still required to conduct a weekly functional integrity inspection of the ingot plant.

Conditions H.5 and H.7. The particul ate emissions for th e alumina railcar unloading dust collector and the bath cr usher dust collector are limited to 0.1 gr/dscf. Tests conducted in May of 2008 showed resu lts of 0.0010 gr/dscf and 0.0018 gr/dscf respectively. Alcoa uses th e same type cloth bag in all it’s baghouses. All of the baghouses throughout th e plant handle similar materials. Therefore, Ecology initially assumed that 0.005 gr/dscf was easily achievable and
that these units would be in continuous operation . Under these assumptions, these units, while still very small sources, would emit more than 0.75 tons/year each (the IEU threshold). Because bot h units have a fairly high flow, a source test is required once every five years and upon Ec ology’s request. More frequent source testing is not necessary due to the low level of likely emissions from these sources, the requirement for weekly inspections and the history of good operation and maintenance at the Alcoa facility.

Small Baghouse Units

Monitoring requirements for other baghouse un its include the O&M and functional integrity requir ements described above.

Routine source testing of units OH-6, OH -8, OH-15 and OH-30 (Conditions H 9, H.11, H.13 and H.15) is not proposed. The material handled by these baghouses is alumina and Alcoa uses the same bag ma terial in all units. Similar performance is expected from baghouses with similar characteristics and proper O&M. Data
from the source tests that have been conducted show emissions below any
allowable limits.

Page 12 of 25 March 2010E) Conditions I. 6 and I.7. SO 2 Permit Conditions:

Chapter 173-415 WAC limits sulfur dioxide emissions from aluminum smelters to 60 lb per ton of aluminum produced on a monthly maximum basis, and also limits
emissions to no more than 1,000 ppm SO 2 . Smelters presently control SO 2 emissions by limiting sulfur content in raw materials, pa rticularly petroleum coke. The permit requires Alcoa Wenatchee Works to determine SO 2 emissions by mass balance calculation or alternatively by source testing. The equation used for
the mass balance calculation to determ ine compliance with the 60 lb SO 2 /ton Al
limit is as follows:

SO 2 /ton Al = ( Σ Cx0.9S C + Σ PxS p + Σ GxS g ) x 40 / Al

where C, P, and G are the coke, pitch, and fuel oil usage during the month from each shipment, in tons; S C , S P , and S g are the sulfur conc entration of each shipment of coke, pitch or natural gas re spectively, expressed as a percentage; and Al is the aluminum pr oduction for the month.

The factor of 40 derives from converting tons of raw materials to pounds (2,000 lbs/ton), converting the percentage of sulf ur in raw materials to a decimal fraction (100), and converting the weight of sulfur to the weight of SO 2 (1 lb sulfur
combines to make 2 lbs SO 2 ). 2000/1 00 X 2 = 40

Using a worst-case analysis, Ecology determined that Alcoa Wenatchee Works would be incapable of violating the 1,000 ppm SO 2 standard, with the possible exception of an extreme upset conditio n. Therefore, no routine monitoring for this standard is proposed.

F) Condition I.10. Ambient and Forage Fluoride St andards and Monitoring:

Order No. 02AQIS-3459 describes prior monitoring and modeling of ambient and forage fluoride near the plant. Based on the findings stated in the order, ambient fluoride standards are consistently met a nd no monitoring is required, as long as gaseous fluoride emissions from the facili ty have not exceeded 327 lbs/day at any time during the preceding 12 month period. Based on the findings stated in the order, forage standards are consistently met and no monitoring is required, as long as an annual vegetation survey is conducted and a survey is conducted to certify
that no livestock is raised for commercial production within a five mile radius of the plant. The requirements of this orde r are state only cond itions in the permit.

G) Conditions for other parameters not required by MACT

Condition A.1. Benzene pl us toluene are limited to a combined total of 1 ppm

Page 13 of 25 March 2010from the green mill liquid pitch vent (67 A). The emissions fro m the liquid pitch tank are treated by an oil sc rubber followed by a charcoal filter. Either unit has the capability of reducing emissions below the 1 ppm limit. The charcoal filter is capable of operating fo r a year without maintena nce but Alcoa procedures require that it be checke d every six months. The sc rubber system operation is checked weekly and corrective action is take n if the pressure on the liquid pitch pump falls outside an operat ing range of 70-100 pound s. Source tests have
shown emissions to be incompliance. The averag e combined emissions of
benzene and toluene we re less than half the standard (App endix C). Weekly inspections and observation of operating parameters in condition A.3 constitute periodic monitoring for this emission unit and further source testing is not

necessary.

Condition A.4. VOC from the liquid pitc h scrubber vent is limited to 1 ppm above background levels. Tests at 174 points showed no exceedances. Testing annually or upon Ecology’s request is adequate periodic monitoring for this unit.

Condition A.7. MACT establ ished the dry coke scrubbe r as preferred technology
for control of POMs from the green mill. Ecolog y added a POMs emission
standard of 0.70 lb /hr when approving the notice of construction for the dry
scrubber Source tests have shown emissions to be less than 40% of the allowable. The source test required every 5 years and the MACT requirements for parametric monitoring specified in condition A.12, fulfill the requirement for periodic monito ring for POMs.

H) Condition D.2. Potroom Op eration & Maintenance:

WAC 173-415-030(6) requires owners and operators to operate and maintain facilities and equipment in a manner cons istent with good air pollution control practice. WAC 173-415-030 (1)(b) requires owners a nd operators of center worked prebake pots to design the primar y emission control system “so that the
control of fluoride emissions will be e quivalent to a total fluoride collection efficiency of ninety five percent”. Potr oom practices and inte grity of pot shields are the major factors determining collectio n efficiency. Further, once pot gasses are collected, the alumina dry scrubber sy stems are very effective in removing fluoride and particul ates. Except during startup, secondary emissions monitoring will be the sole monitoring requirement for potroom O&M if emissions do not
exceed 1.7 lbs TF/ton of alumi num produced. This level is below the 1.9 lbs TF/T aluminum produces, requir ed by MACT. This is 10% below the MACT level which was based on the emissions of the best operating plants. In addition, Alcoa
has demonstrated that in order to achieve the 1.7 lbs TF/ton standard, they must consistently maintain a collection efficien cy of greater than 95%. Due to Alcoa Wenatchee Works’ good operating record and early compliance with MACT

Page 14 of 25 March 2010standards, Ecology has determined that more prescriptive O&M requirements, such as ongoing monitoring of collection efficiency, are not necessary to assure good O&M at this facility. If 1.7 lbs/ton is exceeded, additional m onitoring and action is required. Actions required in clude a root cause an alysis for the first exceedence and weekly in spections of potroom ope rations for the second
exceedence. If 1.7 lbs TF/t on is exceeded more than 6 times, the company will be considered out of compliance with th e O & M requirement of Condition D.2. Because roof emissions are monitored using a Method 14 manifold only in Rooms 6 and 20 and by continuous emissions m onitors (CEMs) in all potrooms,
determination of secondar y emissions would be de termined by correlation
between Method 14 data and CEM data.

During startup, the provisi ons of the Startup Shutdo wn and Malfunction (SSM) plan will apply.

I) MACT

In October, 1997, USEPA promulgated National Emission Standards for
Hazardous Air Pollutants (NESHAPS) representing Maximum Achievable Control Technology (MACT) for the primar y aluminum industry. These rules are contained in the Code of Federal Regulations at 40CFR Part 63, Subchapter LL. Hazardous air pollu tants (HAPs) for this industry include total fluoride (TF) and polycyclic organic matter, (POM).

The MACT standards for pr imary aluminum were subc ategorized into major process areas (potlines, past e plants, and bake ovens) that produce emissions of
either or both of these HAPs. Potlines we re further subcataegorized by the type of reduction cell employed. Alcoa Wenatc hee Works is listed in the federal regulations as being within the center-worked prebake one (CWPB1) subcategory.

In prebake plants, including CWPB1 plan ts, potlines produce fluoride in both gaseous and particulate form. Total fluoride standards address both gaseous and particulate forms of fluoride. MACT standards for prebake potlines address only total fluoride because POMs are dr iven off from the anode material during the anode baking process and are no t of concern in prebake plant potline emissions. Paste production plants (or “green mill” as it is known at Alcoa Wenatchee Works), produce POM emissi ons but fluoride emissions are not significant. Incoming coal tar pitch, used to manufacture green anodes, contains substantial quantities of volatile pol ycyclic hydrocarbons which escape during the melting, mixing and pressing processes within the carbon plant. MACT standards for paste plants require a specific technology for POM emission control. Dry coke scrubbers are the preferred tec hnology although other

Page 15 of 25 March 2010technologies may be used if equivalenc y is demonstrated. Alcoa Wenatchee Works has already installed a dry coke scrubber. Numerical POM limits are not included in the MACT standards. Anode bake ovens produce both fluoride and POM emissions. At Alcoa Wenatchee Works, these are collected and treated in an existing dry alumina scrubber system.

Alcoa Wenatchee Works has taken a proa ctive approach to implementing MACT requirements and are in compliance with MACT emission standards. Ecology has included the MACT requirements in the Draft Air Operating Permit.

On March 23, 2000, the USEPA promulgate d National Emission Standards for
Hazardous Air Pollutants (NESHAPS) representing Maximum Achievable Control Technology (MACT) for the seconda ry aluminum industry. These rules are contained in the Code of Federal Regulations at 40 CFR Part 63, Subpart RRR. Hazardous air polluta nts (HAPs) for this indust ry include organic HAPs, inorganic gaseous HAPs (hydrogen chloride , hydrogen fluoride and chlorine) and particulate HAP metals. These MACT st andards apply to se condary aluminum production facilities using clean charge , aluminum scrap, foundry returns or
molten metal as the raw material and performing, among othe r things, one or more of the following proc esses: furnace operations such as melting, holding, refining, fluxing or alloying; in -line fluxing; or dross cooling.

The facility was required to demonstrate compliance with the secondary MACT requirements for the existing sources by March 24, 2003. Due to the plant curtailment, data from sister Alcoa plan ts with similar operations was used to preliminarily demonstrate the capability to meet the complian ce requirements. The facility demonstrated complian ce within 180 da ys of start-up.

On September 14, 2004, EPA promulgated the final National Emission
Standards for Hazardous Air Pollutant s (NESHAPS) representing Maximum Achievable Control Technology (MACT) for industrial, commercial, and institutional boiler and process heat ers (Boiler MACT) that established standards and certain exemptions from this source category. Subsequent to promulgation, the U. S. District Court for the District of Columbia vacated the Boiler MACT Rule in July 2007. Th e rules were contained in the Code of Federal Regulations at 40 CFR Part 63, Subpart DDDDD. There are currently no standards or exemptions fo r emission units previously identified as being in the industrial, commercial, and institutional boiler and process heaters source category. These circumst ances have created a situation that was not contemplated or addressed by either the CAA or the Subpart A regulations of 40 CFR Part 63.

Page 16 of 25 March 2010At the time of renewal. it was unc lear what actions (if any) Alcoa Wenatchee Works was to take in respons e to, the absence of final regulations from USEPA, the absence of any di rect requests for information from Ecology, and the court’s vacature of the Boiler MACT.

In an effort to ensure that a complete title V renewal applications was filed, Alcoa Wenatchee Works prepared a listi ng of all boilers a nd process heaters (regardless of size) that may be subject to either a State case-by-case “Equivalent Emission Limitation by Pe rmit” determination pursuant to (112(j)) and/or the future Boiler MACT standards. In addition, information indicating that the listed fu el burning emission units may be subject to future applicable requirements is hereby include d as part of the renewal. This
information is listed below.

Unit ID Description Capacity (MMBtu/hr) Fuel Type

BH-1, BH-2 Boilers 30 MM Btu/ hr Natural gas, diesel upon gas curtailment only

IP-16 Moisture drying

oven 2.5 MM Btu/hr Natural gas

Neither Ecology nor USEPA have esta blished a NESHAP for industrial, commercial, and institutional boiler and process heaters located at Alcoa
Wenatchee Works.

J) Insignificant Emission Units

Monitoring, recordk eeping, and reporti ng has not specifically been required by Ecology for insignificant emission units pe r WAC 173-401-530(2)(c). Therefore no monitoring, recordkeep ing, or reporting requirem ents for insignificant emission units are included in the perm it. In the event that monitoring, recordkeeping, and reporting requirement s are imposed pursuant to WAC 173- 401-530, an IEU would no longer qualify for the exemption from operating permit testing, monitori ng, reporting and recor dkeeping requirements.

One additional IEU, a forging quench ex haust, was added during the 2008 AOP renewal process. The forging furnace is already listed as an IEU as FF-6
“Blacksmiths Gas-Fi red Forge”. This furnace ha s a small exhaust outside the building. The forging qu ench sits beside the furnace, and was not listed previously because it was not exhausted outside the building . A small hood and
exhaust will soon be installed to vent fumes that occur when quenching hot forgings into the special oil bath of the quench. The purpose of this exhaust is to

Page 17 of 25 March 2010protect maintenance shop employees who use the quen ch. Emissions will be
well under the 2 TPY VO C threshold for IEU note d in WAC 173-401-530 (4) (d). Emissions can be easily calculated based on annual quen ch replentishment
volumes.

K) Corrective Action

There is a requirement to initiate co rrective action in many conditions of the permit. Initiating co rrective action can include, but is not limited to, preparing a work order, ordering parts, shutting down th e unit, or completing the repair.

L ) Best Available Retrof it Technology (BART)

In 1999, US Environment Protection Ag ency (USEPA) published regulations to address visibility impairment refe rred to as regional haze (64 FR 35714, July 1, 1999). The regional haze rule promulgated by USEPA requires States to develop and submit implementation pl ans (SIPs) to address regional haze visibility impairment in 156 Federally-pro tected parks and wilderness areas. It also requires the installation of Best Availabl e Retrofit Technology (BART) for certain large stationary s ources that were put in place between August 7, 1962 and August 7 1977, which ha ve the potential to emit 250 tons or more of a visibility-impairing ai r pollutant, and whose operations fall within one or more of 26 specifically listed source categories found to be emitting “any air pollutant which may reasonably be anticipated to cause or contribute to any impairment of visib ility in any such area.’’ Primary
Aluminum Ore Reduction Plants are one of the 26 specifically listed source categories and emission units at the Al coa Inc., Wenatchee Works were put in place between August 7, 1962 and A ugust 7 1977 and have the potential to
emit 250 tons or more of a visi bility-impairing air pollutant.

An analysis was performed to assess the visibility impacts of sulfur dioxide (SO 2 ), particulate matter (PM) and n itrogen oxides (NOx) emissions from Alcoa’s BART-eligible sources to de termine if they may reasonably be anticipated to cause or cont ribute to impairment of visibility in any of the federally mandated Class I areas w ithin 300 kilometers of the Alcoa Wenatchee Works facility. The imp act analysis was performed by the permitee pursuant to procedures and protocols approved by the Washington Department of Ecology (WDOE).

The change in light extinction relativ e to the natural background due to SO 2 , NOx and PM 10 from the Alcoa Wenatchee Works BART eligible sources was computed base on the 2003-2005 emission. The predicted impacts on

Page 18 of 25 March 2010Page 19 of 25 March 2010 the worst 98th percentile day duri ng the three annual periods were 0.379 deciview, which is well below the 0. 5 threshold established by WDOE. Therefore, the conclusion from the modeling analysis is that the Alcoa Wenatchee facility is not subject to BART controls.

M) Greenhouse Gas

There are currently no rules governing greenhouse gasses. Alcoa will comply with all greenhouse gas applicable requirements that result from rules
that become effective in the future.APPENDIX A

ORDERS

Orders applicable to Alcoa Wenatchee Works include:

02AQIS-3459

Page 20 of 25 March 2010Page 21 of 25 March 2010 APPENDIX B

PROCESS EMISSION SUBJECT TO SPECIFIC REQUIREMENTS IN ADDITION TO

GENERALLY APPLICABLE REQUIREMENTS EMISSION UNITS SUBJECT TO ONLY

GENERALLY APPLICABLE REQUIREMENTS IEUs

Green Mill, Process #2 GM – 3 Pitch Storage Tank Sc rubber GM – 5B Bldg. 52 Coke Storage GM – 1 Pitch Railcar Unloading
GM -17 Dry Coke Scrubber which includes:

GM – 13 Mixer Vents 1, 2, 3, 4, 5, 6, 7, 8, & 9;
GM – 14 Conveyor beneath Mixers; GM – 15
Conveyor to Anode Forming; and GM – 16
Anode Forming GM – 6 Green Anode Reject Storage GM – 2 Pitch Tank

Relief Valve

GM – 7 Butt Storage GM – 4 Hot Oil Boiler,
Storage Tank, & Pumps

GM – 9 Ball Mill
Baghouse
GM – 10 Bldg. 54 – Dust collector for Coke
Storage GM – 8 Skipped Number GM – 5A Railcar Coke
Unloading

GM – 11 DS8 Coke Fines
Baghouse

GM – 12 M2 Coke Scales
Baghouse
GM –18 bldg 55 DC

Anode Baking, Process #3 BF – 1 Anode Storage

Lanes

BF – 2 Anode Transfer

to Furnace

BF – 10 A446 Reactor # 1 Stacks (BF – 4
Anode Bake) BF – 14 446M Alumina
Storage Baghouse

BF – 11 A446 Reactor # 2 Stacks (BF – 4
Anode Bake) BF – 8 Bldg. 58
Baghouse for Anode
Cleaning

BF – 12 A446 Reactor # 3 Stacks (BF – 4
Anode Bake) BF – 9 Bldg. 62
Baghouse for Anode
Cleaning and Kempe

Machine

BF – 13 A446 Reactor # 4 Stacks (BF – 4
Anode Bake)

AA – 1 Anode Stub

Hole Vacuum Anode Assembly/Rodding,

Process #4 AA – 2 Iron Induction

Furnace
AA – 3 Butt Crusher Baghouse AA – 5 Rod Straightening

Press No. 1
AA – 4 Butt Blast Baghouse AA – 7 Magnetic
Separator

AA – 9 Welded Stub
Repair/Replacement and
Portable Welding Filter

AA – 8 Butt Tank
Baghouse
AA – 10 Anode Cleaning 32T Baghouse

AA – 11 Induction Furn ace Baghouse which

includes: AA – 12 Iron Induction Furnace and
AA – 13 Rod Brushing Potlines, Process #5 PL – 0 Potroom Roof Vents which include:
PL – 1 Anode Insertion and Repositioning;

PL – 2 Bath Material Addition: PL – 3 Alumina
Hopper Filling Stations and Pot Alumina
Addition; PL – 4 Pot Tapping; PL – 5 Anode
Setting; PL – 6 Bath Crust Breaking; PL – 7
Aluminum Tapping; PL – 8 Bath Tapping;
PC – 1 Water Cooling of Pots; PC – 2 Bath
Material to Bath Recycle; PC – 3 Spent Potliner
Removal; PC – 10 New Pot Start-up; PL – 9 Floor SweepingsPROCESS EMISSION SUBJECT TO SPECIFIC REQUIREMENTS IN ADDITION TO
GENERALLY APPLICABLE REQUIREMENTS EMISSION UNITS SUBJECT TO ONLY
GENERALLY APPLICABLE REQUIREMENTS IEUs

PR – 1,2,3 A398 Reactor for Lines 1, 2, and

3 which includes: PL – 12 Pot Fumes from Lines 1,2, and 3 and PC – 11 Fugitives from
Pot Bak e -in
PR – 4 A398 Reactor for Line 4

PR – 5 Dry Scrubber for Line 5 which
includes: PL – 10 Pot Fumes from Line 5 and PC – 11 Fugitives from Pot Bake CC – 1 Crucible Cleaning Machine Baghouse Pot Rebuild, Process #6 SPL – 1 SPL Processing Baghouse – Bldg.
52M

CM – 2 Kent Mill Baghouse

CM – 5 Potliner Mixer Baghouse

CM – 6 Seam Mix
Transfer Boiler House, Process #7 BH – 1 Natural Gas Boiler # 1 BH – 3 Condensate
Return Tank

BH – 2 Natural Gas Boiler # 2 BH – 4 Steam Vents on
Boilerhouse Roof Ingot Plant, Process #8 IP – 1 Furnace 1 Exhaust IP – 5 “C” Machine Treatment Unit IP – 6 “C” Machine
Pour and Skim

IP – 2 Furnace 2 Exhaust IP – 8 Crucible Heaters (Natural Gas Burn) IP – 7 “C” Machine Cooling

IP – 3 Furnace 3 Exhaust IP – 10 “A” Machine Natural Gas Preheat IP – 9 “A” Aluminum
Pour and Skim

IP – 4 Furnace 4 Exhaust IP – 15 Free-s tanding Mold Heaters IP – 13 “A” Water Cooling, North Stack

IP – 11 Furnace 11 Exhaust IP – 17 “D” Ma chine Natural Gas Preheat IP – 14 “A” Water Cooling, South Stack

IP – 12 Furnace 5 & 6 Exhaust IP – 18 Skipped Number IP – 16 moisture drying oven

IP – 21 “D” Machine Treatment Unit IP – 19 “D” Machine
Pour and Skim IP – 22 Skipped Number IP – 20 “D” Cooling Fan IP – 26 Crucible Heaters (Natural Gas Burn) IP – 23 Skipped
Number IP – 24 Skipped
Number IP – 25 Dross Cooling

IP – 27 “A” Machine Mold Cooling Spray

IP – 28 “C” Machine Mold Cooling Spray

IP – 29 “C” Machine Ingot Cooling Spray IP – 30 Aspirated Mold Coating

IP – 31“D” Machine Mold Cooling Spray IP – 32 Dross Storage

Room

Page 22 of 25 March 2010PROCESS EMISSION SUBJECT TO SPECIFIC REQUIREMENTS IN ADDITION TO
GENERALLY APPLICABLE REQUIREMENTS E EMISSION UNITS SUBJECT TO ONLY
GENERALLY APPLICABLE REQUIREMENTS IEUs

Maintenance Plant,
Process #9 BS – 1 Mixer

MS – 2 Plasma Torch

Vent FF – 1 Machining
Evacuation Vent FF – 2 Parts Cleaning
Window Vent FF – 3 New Machining
Evacuation Vent

FF – 4 Metal Saw
Evacuation Vent FF – 5 Steam Cleaning

FF – 6 Blacksmith’s Gas-fired Forge FF – 7 Grinder with Dry
Filter

FF – 8 Electrician’s
Work Area Vent FF – 9 Welding, Machining Evacuation

Vent FF – 10 Machining
Evacuation Vent FF – 11 Welding
Window Vent

FF – 12 25 Safe-T
Kleen Stations FF – 13 Metal Sawing
Evacuation Vent

FF – 14 Preheat

Furnace
FF – 15 Sander with Dry Filter FF – 16 Saw with Dry
Filter FF-17 Blacksmith Forge Quench AS – 1 Auto Tailpipe

Hose
AS – 2 Steam Cleaner

CS – 1 Wood Cutting

CS – 2 Paint Booth with Dry Filters CS – 3 Wood Sanding

Ore Handling, Process
#10 OH – 2 43E Baghouse for Alumina Railcar Unloading, Conveyor 41, Bldg. 43D OH – 1 43M

OH – 15 161-730 Dust Collector for Tanks
A160 W and E OH – 3 43R Dust
Collector for Tank 43R

OH – 6 160T-710 Dust Collector for Tank 160T-B

OH – 7 160T-720 Dust
Collector for Airslide

ASO42-1

OH-8 160T-730 dust Collector for Tank 160T-A

OH – 9 160M-720 Dust
Collector for Airslide

AS-160T-1 OH – 10 160M-720,
Dust Collector for AS 160M and F (Airslides)

OH – 11 160R-710
Dust Collector for Tank

160R

Page 23 of 25 March 2010PROCESS EMISSION SUBJECT TO SPECIFIC REQUIREMENTS IN ADDITION TO
GENERALLY APPLICABLE REQUIREMENTS EMISSION UNITS SUBJECT TO ONLY
GENERALLY APPLICABLE REQUIREMENTS IEUs

OH – 12 160R-720

Dust Collector for AS

160R ( Airslides ) OH – 13 161-710 Dust Collector for 160RN, 161, and 162

OH – 14 161-720 Dust
Collector for AS 163RE and 160RN (Airslides)

OH – 18 21RDust
Collector for Tank 21M
and Airslide AS-042-1

OH-19 21 R Dust
Collector for 21R tank
north

OH – 20 19A Dust
Collector for Airslide
AS-19M-2

OH – 21 19C Dust
Collector for Tank 19C

OH – 22 19MS Dust
Collector for Tank
19MS
OH – 24,25,26,27,28
42A710-E Dust
Collector for Airslide

AS-042-2

OH – 29 19T-710 Dust
Collector for Tank AL 19T, Airslides AS19C-1
and AS19C-2

OH – 30 19T-720 Dust Collector for Tank AL 19T

OH – 31 19T-730 Dust
Collector for Airslides
AS19T-1 and 19T-3

OH – 32 17R Dust
Collector for Tank 17R OH – 42 21R (Center)
Dust Collector OH – 43 21R (South)
Dust Collector

OH-45 5 D DC

OH-46 9 D DC BR –1 40A (Bath Crusher) Dust Collector for Bath Storage and Conveyor, Mill Hopper, Conveyor 41, Rotary Br eaker, and Tanks A-E BR-2 Bath Recovery Transfer System

Miscellaneous BL-1 solvent (caustic) wash

BL-2 fume hoods (7)

BL-3 Atomic absorption Units (2) BL-4 Flammables storage
cabinet

Page 24 of 25 March 2010APPENDIX CDATA TABLESPage 25 of 25March 2010