October 1,2007
BY U.S. MAIL & ELECTRONIC MAIL CERTIFIED MAIL NUMBER: 7005 1820 0000 3674 5613 RETURN RECEIPT REQUESTED Ms. Nancy C. Wrona, Director Air Quality Division Arizona Department ofEnvironmental Quality 1110West Washington Street Phoenix, 

### AZ 85007
Re: ASARCO LLC Hayden Smelter-Potentially Subjectto Best Available Retrofit Technology (BART) Determination Dear Ms. Wrona: ASARCO LLC (Asarco) received your July 13,2007letter based on the results of the CALPUFF modeling performed by the Regional Modeling Center (RMC) for the Arizona Department of Environmental Quality (ADEQ). Based on the results of RMC modeling, Best Available Retrofit Technology (BART) determinations will be required for certain emission units at Asarco's Hayden smelter. Asarco notes, however, that these units already have BART-equivalent controls and that additional controls are not necessary. A. Emission Units Potentially-Subject- to- BART Based on the results of RMC modeling, ADEQ has determined that the following emissionsunits at the Hayden smelter arepotentially-subject-to-BART:

-,, 

# 1 Anode Furnace 1-3 

# I SO2,,PM

Table 1:Potentially-Subject-to-BART Emission Unit(s)

In addition the June 9, 2006 ADEQ letter from Ms. Wrona to Mr. Tom Moore states that converters 1-5 and anode furnaces 1-3 at Asarco's Hayden smelter are BARTeligible units for at least one pollutant that can potentially cause visibility impairment in a Class I area. EmissionUnit(s) Converters 1-5

100 HAYDEN AVENUE
. P.O. BOX 8.HAYDEN, ARIZONA 85235 TEL 520 356 7811 Potentially-Subject-to-BART So,. PM

### In Section 1.0 of Attachment 3, ADEQ identifies potentially BART-eligible emissions units for various source categories using a three-step process. The results for the Primary Copper Smelters are presented in Section 5.3. The data for the Hayden smelter are presented in Section 5.3.1. There are inaccuracies in the data that we wish to correct as follows: Source of information: ASARCO LLC records Step 1:Are Emission Units Part of a Categorical Source? Yes. Fluid Bed Dryers (2), INCO Oxygen Flash Furnace (1) Converters (5), Anode Furnaces 0-2, Acid Plant (1) (A.A.C. R-18-2-406(2) 

### (g) and 1601(2) (h)) No: NIA Step2: Are Emission Units in Step 1 Date Eligible? Fluid Bed Dryers (2): Constructed 1983-No INCO Oxygen Flash Furnace (1): Constructed 1983-No Converters: Three-converter operation prior to 1962. One converter was enlarged in 1965 from 13x 32 to 13x 35 feet, converters #I and #4 were added in 1968-"two or three of five are date eligible" Anode Furnaces #1 and #2: Constructed 1972 -Yes. Anode Furnace #0: Constructed 200 1-No Acid Plant (1): Constructed 1983

## -No Step3: 

### C Potential to Emit 

### >250 TPY ofVisibility Impairing Pollutants? 2004 Actual Emissions Inventory Information

Yes for SO,.

Smelter Total for 

### BART Eligible Emission

Notes: Acid Plant may be considered control device for SOz. If so, part eligibility may be impacted by installation ofthis control. 

### PMlo(~PY) 157.3 Unit Total Hayden 2 1.4(2converters) 23.3 (3converters) NOx(tpy) 47.4 SO, (tpy) ' 19394.9 6903 (2 converters) 10337 (3 converters) 61.1 (2converters) 70.0 (3converters)

### The RMC modeling was done with NO,, PM and SO2 emissions from the entire smelter. The results (Table 1 of the July 13, 2007 letter) indicate that the Hayden smelter would be BART- eligible for the five converters and three anode firnaces at Hayden. For PM, the modeling shows an average visibility impact of 0.53 deciviews (dV) for the Galiuro Wilderness. The PM emissions associated with the BARTeligible emissions units are 61.1 tpy (2 converters) and 70.0 tpy, compared to 157.3 for the entire smelter. If emissions from the BART-eligible units alone are modeled the visibility impact would be below the 0.5 dV threshold. Therefore, BART determination is necessary only for SO2. B. BART 

### for SO2 Emissions from Relevant Emission Units atHayden Smelter During the deliberations of the Market Trading forum of the Western Regional Air Partnership (WRAP), all parties involved including ADEQ and the U.S. Environmental Protection Agency (EPA), agreed that the controls and emissions limitation for primary copper smelters already met BART for SO2,This was reflected in the milestones included in the State Implementation Plan (SIP) that ADEQ submitted to EPA under 40 CFR 51.309 (Section 309 SIP). The milestones being proposed for inclusion in the model 308 SIP currentlybeing developed by the WRAP include an allowance of 26,000 tons of SO2 for the Hayden smelter and are based on the fact that the smelter is at or beyond the BART requirements. Asarco believes that BART controls for SO2 are already in place at Asarco's Hayden smelter and no additional controls are necessary. Asarco looks forward to working with ADEQ to confirm this conclusion. If you have any questions please call Jack Garrity at 520-356-3284.
Sincerely,

John Shaw General Manager Hayden Operations &

### Adrnin. cc: Mr. Eric Massey, Manager Air Quality Compliance Section, ADEQ