UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION/X

Ms. Brenda Bums, Commissioner Arizona Corporation Commission 1200 West Washington Street Phoenix, Arizona 85007-2927
DearMs

. Bums: 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 protected national 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 on the regional haze Federal Implementation Plan (FIP) regarding three powerplants in Arizona (Apache Generating Station, Cholla Power Plant and Coronado Generating Station.) We plan 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

. These two hearings are in addition to the public hearing in Phoenix on July 31 , 2012. We will carefully and thoroughlyreview comments, including any additional technical information, submitted during the public comment period prior to making our final determination.
As background, underthe 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 Arizona had not 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 ofintent to sue followed by a lawsuit covering dozens of states, including Arizona, for which we had not approved a Regional Haze SIP orpromulgated a Regional Haze FIP under the CAA. Shortly thereafter, in February 2011 , Arizona submitted a new Regional Haze SIP. Submittal ofthis plan, however, had no effect on the 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 complex negotiations involving deadlines for numerous states, the most recent 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, we proposed 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,

Pri11ted 011 Recycled PaperCholla Power Plant and Coronado Generating Station. We have proposedto approve the State's determination that these sources are subject to 

### BART, and to approve the emissions limits for sulfur dioxide (S02) and particulate matter (PM1o) 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 FIP containing new emissions limits for 

### NOx as well as associated compliance requirements. This proposal was published in the 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 haze plan. Prior to our July 20, 2012 proposal, EPA worked with Arizona, the affected utilities, the National Park Service, the environmental litigants, and others to gather information useful in preparing ourproposal. EPA provided a prepublication version ofthe proposal that was published in the Federal Register to various parties, including the State, on July 2, 2012. States are entitled to deference to their reasoned decisions when consistent with the CAA and the Regional Haze Rule. However, we cannot give deference to state decisions ifwe find that the state's analysis does not comply with the regional haze requirements. In this case, where we have proposed a FlP, we are committed to continuing to work with the State ofArizona on approvable revisions to its SlP. When an approvable regional haze SlP revision is submitted to the EPA and approved, we will withdraw our FlP. Again, thank you for your letter

. Ifyou have further questions, please contact me or your staffmay call Colleen McKaughan, Associate Director at 520-498-0118. Sincerely,

Director, Air Division