STATE OF COLORA.OO
 

John W. Hickenlooper, Governor
 

Christopher E. Urbina, MD, MPH
 

Executive Director and Chief Medical Officer
 

Dedicated to protecting and improving the health and environment of the people of Colorado 

4300 Cherry Creek Dr. S. Laboratory Services Division
 

Denver, Colorado 80246·1530 8100 Lowry Blvd.
 

Phone (303) 692-2000 Denver, Colorado 80230-6928
 

Located in Glendale, Colorado (303) 692-3090
 

http://www.cdphe.state.co.us 

May 10,2011 

Colorado Department 

of Public Health 

and Environment 

Deborah Lebow 

Air Program Director 

U.S. Environmental Protection Agency, Region VIII 

1595 Wynkoop Street 

Denver, CO 80202-1129 

RE: Colorado's Interstate Transport State Implementation Plan (SIP) and Greenhouse Gas (GHG) 

Permitting Authority 

Dear Ms. Lebow: 

The State of Colorado ("the State") is writing to clarify ambiguities in the Interstate Transport SIP 

submitted to EPA on March 31, 2010, and the Infrastructure SIP certification submitted to EPA on 

January 7, 2008. The Interstate Transport SIP submittal addressed the requirements of section 

110(a)(2)(D)(i) of the Clean Air Act (CAA) for the 1997 ozone and PM2.5 NAAQS, and the 

Infrastructure SIP certification addressed the requirements of CAA sections 11 O(a)(l) and (2) for the 

1997 ozone NAAQS. In the Interstate Transport SIP, the State indicated that it relied on its current SIPapproved Prevention of Significant Deterioration (PSD) permitting program to satisfy the requirement of 

CAA section llO(a)(2)(D)(i)(II) that SIPs contain adequate provisions preventing interference with 

other states' required PSD programs. The submittal date of March 31, 2010 for the Interstate Transport 

SIP was prior to EPA's December 30, 2010 promulgation of the Limitation ofApproval ofPrevention of 

Significant Deterioration Provisions Concerning Greenhouse Gas Emitting-Sources in State 

Implementation Plans ("PSD SIP Narrowing Rule") (75 FR 82536), which withdrew approval of 

Colorado's PSD program to the extent that the program applied PSD permitting to GHG emissions 

increases from GHG-emitting sources with emissions below the thresholds established in EPA's June 3, 

2010 Prevention ofSignificant Deterioration and Title V Greenhouse Gas Tailoring Rule ("Tailoring 

Rule") (75 CFR 31514). The State wishes to clarify that, to satisfy the requirement of CAA section 110 

(a)(2)(D)(i)(II) that SIPs contain adequate provisions preventing interference with other states' required 

PSD programs, the State's Interstate Transport SIP submission should be read to rely only on the portion 

of Colorado's PSD program that remains approved after the PSD SIP Narrowing Rule took effect on 

December 30, 2010. 

Page lof2 
Similarly. the Infrastructure SIP certification was submitted to EPA on January 7, 2008, prior to the 

December 30, 2010 promulgation of the PSD SIP Narrowing Rule. In that certification, the State 

indicated that it relied on its current SIP-approved PSD program to meet the requirements of CAA 

sections IIO(a)(2)(C) and (J). The State wishes to clarify that, to satisfy the requirements of CAA 

sections 11 0(a)(2), the State's Infrastructure SIP certification should be read to rely only on the 

portion of Colorado's PSD program that remains approved after the PSD SIP Narrowing Rule took effect 

on December 30, 1010. 

If you have any questions, please work with Dena Wojtach at (303) 692-3147 or dena.wojtach@state.co.us 

of my staff regarding this issue. 

~------ Paul Tourangeau, Director
 

Colorado Air Pollution Control Division
 

Page 2 of2