UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX

Mr. Gary Pierce, Chairman Arizona Corporation Commission 1200 WestWashington Street Phoenix, Arizona 85007-2927
Dear Mr. Pierce: 75 Hawthorne Street San Francisco, CA 94105-3901 

## JUL 2 6 2012

Thank you for your interest in Arizona's plan to address regional haze in protectednational parks and wilderness areas as required under the Clean 

### Air Act (CAA). I am responding to yourrecent letter requesting an extension ofthe public comment period and additional hearings.
We agree to extend the deadline for public comment and increase the number ofpublic hearings to provide ample opportunity for review and comment onthe regional haze Federal Implementation Plan (FIP) regarding three powerplants in Arizona (Apache Generating Station, Cholla Power Plant and Coronado Generating Station.) Weplan to extendthe public commentperiodbytwo weeks, for a total of60 days, ending on September 18,2012. We also plan to conduct two additional public hearings, one ofwhich will be held in northern Arizona (Holbrook}, and one in southern Arizona (Benson). These are scheduled for August 14 and 15,2012,respectively. Thesetwo hearings are in addition to the public hearing in Phoenix onJuly 31, 2012. We will carefully andthoroughly review comments, including any additional technical information, submitted during the public comment periodpriorto making our final determination.
As background, under the Regional Haze Rule, Arizona was required to submit a Regional Haze State Implementation Plan (SIP) in December 2007. In January 2009, well after the CAA deadline for such action, we made a formal finding that Arizonahadnot submitted a complete Regional Haze SIP. That finding started a two-year clock that could be stopped onlyby our approval ofa SIP orpromulgation of a FIP. In January 2011, we received a notice ofintentto sue followed by a lawsuit covering dozens of states, including Arizona, for which we hadnot approved a Regional Haze SIP orpromulgated a Regional Haze FIP under the CAA. Shortlythereafter, in February 2011, Arizona submitted a new Regional Haze SIP. Submittal ofthis plan, however, hadno effect onthe EPA's legal obligation to promulgate a Regional Haze FIP, unless the EPA was able to approve fully Arizona's Regional Haze SIP.
After lengthy and coinplex negotiations involving deadlines for numerous states, the mostrecent revision to the consent decree requires us to take actions on Arizona's SIP, or adopt a FIP, in two separate sets ofnotices. The final action date for the three powerplants in our current proposal is November 15,2012. The final action for the remainder ofArizona's SIP is July 15, 2013. These dates for us to act on Arizona's SIP are among the latest in the consent decree. Accordingly, on July 20, 2012, weproposed a partial approval and partial disapproval ofArizona's Regional Haze SIP with respect to its determination ofBestAvailable Retrofit Technology {BART} to control emissions from eight units at three electric generating stations: Apache Generating Station,

Printed 011 Recycled PaperChollaPowerPlant and Coronado Generating Station. Wehave proposed to approve the State's determination thatthese sources are subject to 

### BART, andto approve the emissions limits for sulfur dioxide**(S~)** and particulate matter (PMIO) at all the units. We also have proposed to disapprove the 

### BART emissions limits for nitrogen oxides 

### (NOx) at most ofthe units. As a remedy we have proposed a 

### PIP containing new emissions limits for 

### NOx as well as associated compliance requirements. This proposal was published inthe Federal Register on July 20,2012 and is available at: http://www.epa.gov/region9/air/actions/az.html#all.
We are committed to working with Arizona on its regional hazeplan. Priorto ourJuly20, 2012 proposal, EPA worked with Arizona, the affected utilities, the National Park Service, the environmental litigants, and others to gather information useful inpreparing ourproposal. EPAprovided a prepublication version oftheproposal that was published in the Federal Registerto various parties, including the State, on July 2, 2012. States are entitled to deference to theirreasoned decisions when consistent with the CAA andthe Regional Haze Rule. However, we cannot give deference to state decisions ifwe find that the state's analysis does not complywith the regional hazerequirements. In this case, where we have proposed a FIP, we are committedto continuingto workwith the State ofArizona on approvable revisions to its SIP. When an approvable regional haze SIP revision is submittedto the EPA and approved, we will withdraw ourFIP. Again, thank you for your letter. Ifyouhave further questions, please contactme or your staffmay call Colleen McKaughan, Associate Director at 520-498-0118. Sincerely,

Deborah Jordan Director, Air Division