p. 1 of 10

From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ]
Sent: Friday, January 03, 2014 10:06 AM
To: Putney, David Subject: RE: Draft emissions file for the Century Aluminum facilities

See my comments below in red.

From: Putney, David [ mailto:putney.david@epa.gov ] Sent: Friday, January 03, 2014 8:30 AM
To: Coomes, Jamie Subject: RE: Draft emissions file for the Century Aluminum facilities

Jamie,

There are several schools of thought on the risk mo deling

done here and the amount of effort that should be d edicated to ensuring that the individual parameters (e.g., e mission rates, stack height and diameter, exhaust temperatu re and velocity, etc.) are exactly correct, given the amou nt of uncertainty inherent in the model itself. That bein g said, I believe it is worthwhile to make quick correction s if/when possible. There is nothing quick or exact a bout the emissions estimates – but we (both industry and EPA ) have put significant effort into generating those and I have a fair amount of confidence in them. However, EPA inf ormation on emission point locations is limited. So, if you have the correct stack parameters, we can quickly change the model inputs to reflect those parameters and it may be we ll
worthwhile to do so.

When I filter the spreadsheet to show only potline stacks I see 3 sources, as follows:

ID Height (ft) Diam (ft)
202 197 13.1 (I believe this is referring to line 5 stack)
24 397 25.9 (Line 1-4)

Stack
9 200 9 (carbon bake Stack)

My understanding is that Lines 1 through 4 exhaust via common ductwork to one stack (presumably with ID 24 sincep. 2 of 10

that has the correct height and diameter) This is correct

. As I noted in my email last night, the earlier subm ittals for this facility suggest that there is a “stack B” for these potlines (Only other stack for Lines 1-4 is a shorter “bypass” stack which is only used during SSM situations. Not a normal used stack.) – but I do not know
whether stack B would be the one with ID 202 or 9 o r if the associated parameters are correct.

Also, I do not know the height or diameter of the s tack
associated with Line 5 and so do not know if this s tack would be the one with ID 202 or 9 and again, I do n ot know if the associated parameters are correct.

Thanks,

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov

From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ]
Sent: Friday, January 03, 2014 9:00 AM
To: Putney, David Subject: RE: Draft emissions file for the Century Aluminum facilities

What you have below is correct. Line 1-4 stack is 4 00 ft tall and 25 ft diameter. But what you have in the spreadsheet is not correct.

(So, although we may have the wrong numbers, at lea st we are consistently wrong.) Is this an issue? Should it be changed to reflect the actual?

Thanks
Jamiep. 3 of 10

From: Putney, David [ mailto:putney.david@epa.gov ]
Sent: Thursday, January 02, 2014 9:53 PM
To: Coomes, Jamie Subject: RE: Draft emissions file for the Century Aluminum facilities

Jamie,

I’d be happy to talk with your consultant about thi s issue. Just send me his/her phone number and I’ll call tom orrow morning (or whenever works best for your consultant ). Until
then let me summarize what I found out. The EPA con tractor that developed the modeling input file in question provided the response found below in red text.

David, We used the same stack height and diameter in 2013 as we used in 2011. And in 2011 we used the same stack h eight
and diameter as we used for the 2009 risk assessmen t, which came out of the NEI. Note also, that these paramete rs do not correspond to the NEI defaults. So, although w e may have the wrong numbers, at least we are consistentl y
wrong.

Also note that according to the response to the 201 1 EPA questionnaire provided for the Century Aluminum of KY facility (attached – see page 119 of 280) the stack associated with the CWPB3 potlines (lines 1 through 4) is
400 feet tall and the stack associated with the CWP B1 potline (line 5) is 200 feet tall.

Further, the following information was taken from a ppendix I of the report provided for this facility in respo nse to the 2013 testing ICR (attached – see pages 25, 26, 50 and 51 of 53 for the stack for Lines 1 through 4 and pa ges 27 and 52 of 53 for stack B for Lines 1 through 4):

Diameter of stack for Lines 1 through 4 = 311.75 in ches (about 25.9 feet); see pages 25, 26, 50 and 51 of 5 3

Diameter of stack B for Lines 1 through 4 = 311.75 inches; see pages 27 and 52 of 53p. 4 of 10

Approximate height of stack for Lines 1 through 4 = 395 feet; see page 2 of 53 (also confirmed in section 6 .1 on page 4 of main report).

We can talk more about this tomorrow.

Thanks,

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov

From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ] Sent: Thursday, January 02, 2014 3:59 PM
To: Putney, David Subject: RE: Draft emissions file for the Century Aluminum facilities

My consultant was going to call you and discuss thi s.

From: Putney, David [ mailto:putney.david@epa.gov ] Sent: Thursday, January 02, 2014 2:20 PM
To: Coomes, Jamie Subject: RE: Draft emissions file for the Century Aluminum facilities

Jamie,

Let me talk with my contractor about this and get b ack to you with an answer – hopefully this evening but mig ht be tomorrow morning. The short, from the hip answer is that he likely got the data from either the 2011 questionna ire response for this facility, the 2013 testing ICR re sponse for this facility, or from the NEI database (if the
information was not available in either of the othe r 2 sources).p. 5 of 10

I’ll let you know what I find out.

Thanks,

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov

From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ]
Sent: Thursday, January 02, 2014 2:21 PM
To: Putney, David Subject: RE: Draft emissions file for the Century Aluminum facilities

David,

What is the source for our facility here in Hancock county
for Potline Stack? Is it CWPB3 Potlines 1-4 or CWP B1 Potline 5? The stack heights and diameter are not correct in your spreadsheet.

We have two different stacks, which one is this ref erring

to?

Thanks
Jamie

From: Putney, David [ mailto:putney.david@epa.gov ] Sent: Monday, December 30, 2013 2:32 PM
To: Coomes, Jamie; Coomes, Brandon; Lane, Sean Subject: RE: Draft emissions file for the Century Aluminum facilities

Jamie,

The possible cell entries for the column with the h eader “Emission Calc Method” include Engineering Judgemen t, EPA Emission Factor (WebFire or AP-42), Stack Test, and (Blanks). First, let me try to clarify those choice s.p. 6 of 10

• Engineering Judgement : This is used for emissions from those sources for which emissions test data is not available and for which testing is not viable ( e.g., speciated POM from pitch storage tanks).

• EPA Emission Factor (WebFire or AP-42) : This is used for pollutants that were not stack t ested at a given facility but that were stack tested at other primary aluminum facilities and for which we developed an emission factor (e.g., lb pollutant pe r ton of aluminum produced) based on the stack tests that were conducted. For example, only the N oranda and Alcoa-Massena East facilities tested for speciated POM (e.g., anthracene, pyrene, etc.) and Cr+6 emissions. Emissions of those pollutants from the other primary aluminum facilities were subseque ntly estimated based on emissions factors generated from the testing conducted the Noranda an d Alcoa-Massena East facilities. (The “WebFire or AP-42” portion of this standard choice label is misleading.)

• Stack Test : This is used for those pollutants for which a giv en facility conducted stack testing in 2013 (e.g., metal HAP, except for Cr+6, from the potline s at the Century Aluminum of Kentucky facility and from the potlines, anode bake furnace, and paste pl ant at the Century Aluminum – Sebree facility).

• (Blanks) : This is for those pollutants for which stack test ing was not viable (e.g., carbonyl sulfide – due to very low concentrations in the secondary potline exhaust) but for which we believe a mass balance approach provides reasonable emissions estimates.

Also, keep in mind that for the risk modeling POM ( as methylene chloride extractable matter - MCEM), and particulate matter emissions data are not included. These data may be used in the decisions on MACT standards (e.g., in the case of POM from prebake potlines or PM as a surrogate for HAP metals from potlines, bake furnac es and/or paste plants), but are not used as inputs to the risk model. Speciated POM and individual metal HAP emissions estimates are used as inputs in the risk model.

So, the direct answer to your question would be tha t emissions of speciated POM from the Century Aluminu m of KY facility were based on emission factors for those P OM species developed based on testing at the Noranda f acility.

Note that estimates of emissions of POM (as MCEM) f rom the potlines at the Century Aluminum of KY facility (wh en we look at possible MACT standards for prebake potline s) will be based on the testing done at that facility. At t his time we are not looking at emissions of POM as MCEM from anode bake furnaces or paste plants as those sources alre ady have
numerical MACT standards for POM as MCEM.

Clear as mud?p. 7 of 10

Thanks, and please let me know if you have any more questions.

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov

From: Coomes, Jamie [ mailto:JCoomes@centuryky.com ]
Sent: Friday, December 27, 2013 10:47 AM
To: Putney, David; Coomes, Brandon; Lane, Sean Subject: RE: Draft emissions file for the Century Aluminum facilities

David,

I am having my testing consultant review our facili ties ICR test data to verify it matches what is on your spreadsheet. Actual stack test data (metal compou nds and mercury) was conducted on Potline stack and roof ve nts.

I have a question as to what EF were used for POM f rom the anode paste plant? Your spreadsheet says EPA emiss ion factors. We have historically used the POM emission factor based on the Example calcs from refractory products NESHAP. I have attached that document. It is on p age 2 Table 1 Pitch bonded Heated Mixer POM (3.9 lbs /ton ).

Is this different than what you have used in your spreadsheet?

Jamie

From: Putney, David [ mailto:putney.david@epa.gov ] Sent: Wednesday, December 18, 2013 8:39 AM
To: Coomes, Brandon; Coomes, Jamie; Lane, Sean Subject: Draft emissions file for the Century Aluminum faci litiesp. 8 of 10

Hello Jamie/Brandon/Sean,

Please find attached to this message a draft emissi ons file (Excel spreadsheet) for the Century Aluminum primar y aluminum production facilities. Columns highlighte d in yellow are available for revisions or to indicate i f
records should be deleted. Please do not overwrite the data in columns that are not highlighted in yellow as this would complicate the development of the final emiss ions file for use in risk modeling.

The tab titled “primary Al category” includes emiss ions from the primary aluminum production operations (e. g., potlines, paste plants, pitch storage tanks, and an ode bake furnaces) at the Century Aluminum facilities as est imated via emission factors developed from test results ob tained in response to the testing ICR sent out in April of 2013. I expect that the stack parameters are correct as-is since industry previously had opportunity to review those items
in CY2010 before the initial residual risk and tech nology review (RTR) proposal for the primary aluminum prod uction source category. There are, however, some emissions (e.g., metal HAP, dioxins, PCB, etc.) that are new to the RTR analysis for the primary aluminum production source category and, although these have been QA/QC’d by contractor and EPA staff, we do welcome feedback/corrections you might have on these emissi ons. A revision column highlighted in yellow is provided f or you to revise emissions (in units of tons per year, tpy ) if

needed.

The tab titled “noncategory” includes 2005 NATA NEI , 2008 NEI and 2010 state HAP data for the Century Aluminu m primary aluminum production facilities. These recor ds are intended to include emissions from operations at yo ur facility which are not directly associated with pri mary aluminum production (primary aluminum emissions are addressed under the first tab, discussed above) or secondary aluminum production (secondary aluminum e missions
will be addressed via the RTR associated with the s econdaryp. 9 of 10

aluminum source category). Revision columns highlig hted in yellow are included for emissions, pollutants, stac k parameters, fugitive parameters and latitude/longit ude. If any of these parameters needs modification, please put the corrected value in the associated revision column ( again, please do not overwrite the data in columns that ar e not highlighted in yellow). Note that fields were also added to identify if a record should be deleted, and a re viewer comment field where you can add a comment if approp riate. Please review these data with the following in mind :

1. Should the operation be included in the spreadsheet ?

a. Does the operation still exist at the facility? If not, or if it exists but is not legally allowed to operate (e.g., you do not have a valid operating pe rmit for this operation) then the operation
and associated emissions need not be included.

b. If the operation does exist at the facility, is it part of any secondary aluminum operations that may exist at your facility? If so, then the operati on and associated emissions need not be included (so as to avoid double counting those emis sions).

c. If the operation does exist at the facility, would the emissions from this operation be considered part of the monitored primary aluminum e missions? For example, if the emissions associated with the operation in question are route d through the control device associated with the paste plant and would be monitored as part of the paste plant emissions then the operation and associated emissions need not be incl uded (so as to avoid double counting those emissions).

2. If the operation should be included, are the cited emissions representative of that operation?

3. If the operation should be included but the cited emissions are not representative of that operation, then please provide representative annual actual em issions in units of tons emitted per year (tpy).

4. Verify or modify the stack parameters and location as appropriate and necessary.

If I might make a suggestion – you can use the filt er function in Excel to narrow down the file to review a single facility at a time.

I do not have any information for a contact at the Century Aluminum facility in West Virginia. Would you pleas e pass this email and attachment along to someone at that facilityp. 10 of 10

that could review this information? Also, would you please forward me that person’s contact information?

Please provide any comments, changes, corrections, etc. to this file to me by close of business on Friday, 01/ 03/14. I understand that more time might be preferable with the holidays upon us, but please give me what you can b y 01/03/14 and remember that you will have another opportunity to make comments and corrections during the upcoming public notice and comment period associate d with the primary aluminum production RTR supplemental pr oposal.

If you have any questions concerning these issues, please feel free to contact me by email or telephone.

Thanks,

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov