### State ofUtah Department of Environmental Quality Dianne R. Nielson, Ph
.D
. Executive Director DIVISION OF AIR QUALITY Richard W
. Sprott Director JON M
. HUNTSMAN. JR
. Governor GARY HERBERT Lieutenant Governor 

# ecti FEB 27 2007

DAQ-012-07 February 13, 2007 Callie Videtich, Director US EPA Region 8 Air and Radiation Program Mail Code: SP-AR 1595 Wynkoop Street Denver, CO 80202-1129 DearMs Videtich: We were surprised and disappointed by the February 1, 2007letterfrom Cindy Cody requesting we withdraw Utah'sFebruary 6, 1996, Diesel Inspection and Maintenance (I/M) State Implementation Plan (SIP) submittal. This request is a complete about face from a previous agreement. On September 18, 2006 we held what we understood was a productive telephone call with members ofyour staffandEPA's Office ofTransportation Air Quality (OTAQ), to discuss Utah's February 6, 1996, Diesel I/M SIP submittal. At the conclusion ofthe call, we believed we reached a common understanding on what would work for both EPA and Utah, specifically that:
• No program credit is presently obtainable

- since no viable technical basis exists to quantify any particulate matter (PM) emissions benefit. • The Utah Diesel I/Mprogram would remain in the SIP as an enduring "SIP strengthening measure" with direct and indirect public health benefits. • There was no request for Utah to withdraw its 1996 Diesel IJM SIP submittal. • Both agencies agreed that finding and repairing smoking vehicles result in real world PMreductions. • EPA would provide Utah with a strong letter endorsing the continuance ofour diesel 

### liM program.

ISO North 1950 West • PO Box 144820 • Salt Lake City, UT 84114-4820 • phone (801) 536-4000 • fax (801) 536-4099 T
.D
.D
. (801 ) 536-4414 • www.deq
.utah.govDAQ-012

-07 Page 2 Utah has led the nation in establishing an effective diesel 11M program for heavy

-duty and light-duty diesel vehicles
. 

### liMjurisdictions in other states have directly benefited from Utah's diesel 11M program experience in establishing their respective programs. As a result of EPA's inaction, Utah County has terminated its diesel 11M program. A withdrawal ofthe Diesel 11M SIP will eliminate any incentive to integrate future diesel Onboard Diagnostics (OBD) testing into our 11M programs and conflicts with EPA's substantial investment in diesel retrofit and idling reduction technology throughout the nation. The promulgation of a more stringent fine particulate standard will likely require Utah to evaluate the effectiveness ofa variety ofcontrol measures, including further controls on diesel vehicles. Withdrawing ourDiesel 11M SIP will not facilitate this process. Ourdiesel 11M program provides an effective mechanism to promote diesel vehicle maintenance and identify modified and tampered vehicles, which is a mounting issue due to the increased availability of aftermarket 'performance' devices. EPA continues to invest significant resources in supporting diesel retrofits and idle reduction on school bus and other fleets. Withdrawing Utah's Diesel 11M SIP is counter to EPA's continued commitments andpriorities and would send an inconsistent message to the public andjeopardize ourremaining diesel 11M programs. While EPA approved the inclusion ofUtah's diesel 11M program in its approval ofUtah's 1991 PM SIP submittal, this SIP was superseded in Utah County with EPA's approval ofthe Utah County InterimPM SIP in 2002. UnderEPA's guidance, the diesel 11M program was not included as a control measure in Utah's 2005 PMMaintenance Plan
. Upon EPA approval ofthe 2005 PMMaintenance Plan, the diesel 11M program will no longerremain as a SIP strengthening control measure in Utah and the program will likely be terminated. Therefore, we can not concurwith the region's request that we withdraw ourFebruary 6, 1996 Diesel 

### liM SIP submittal and we request final rulemaking on Utah's submittal. We would also appreciate bettercommunication in the future when a decision is made to reverse an agreement.

cc: Cynthia Cody Lee Cook Suzanne Rudzinski Attach: EPA Letter, 8P-AR, February 1, 2007 '.

### UNITED STATES
.ENVIRONMENTAL PROTECTION AGENCY REGION 8



### Ref: SP-AR Mr. Richard W. Sprott, Director Utah Division ofAir Quality 150 North 1950 West PO Box 144820 Salt Lake City, UT 84114-4820 Dear Mr. Sprott: 1595 WYNKOOP STREET DENVER, CO 80202-1129 http://www.epa.gov/region08 

## FEB 1 'lf/J7

Thank you for the time you spent with us and EPA's Office ofTransportation and Air Quality (OTAQ) on September 18,2006, discussing Utah's February 6, 

### 1996, Diesel Inspection and 

### Maintenance (liM) 

### State Implementation Plan (SIP) submittal. We now have abetter understanding ofUtah's needs and interests. On July 

### 8, 1994, we approved Utah's attainment SIP addressing PMw for Salt Lake and Utah Counties. In tl\is approval, we approved Utah's diesel 1/M program· as a SIP strengthening measure, but did not assign any emission reduction credit at the time. Pleaserefer to 59 FR35036 or 57 FR 

### 60149 for a more detailed description in the notice ofproposed rulemaking. At this time, we do not have a technical basis for quantifying the particulate matter benefits ofan opacity 

### liMprogram. As a result, we are not able to assign a specific level ofcredit in MOBILE6 to such programs. Nevertheless, it is likely that finding and fixing smoking vehicles results in net PM benefits in thereal world. As 

### we discussed on the call, technology is under development that may allow for accurate measurement ofPM emissions from diesel vehicles in an 

### 1/M setting. Such technology could lead to development ofprecise quantification ofdie5eli/M program benefits. Our recommendation is to resubmit, for EPA approval, an updated diesel 1/M 

### program SIP at a later date, when the evaluation can be quantified with this new technology, and to send us a letter withdrawing the February 6, 1996 version ofthe diesel 

### 1/M SIP
.

. - --- --- --- --- --- ----- --- --- ----- ---

. ---------------------------------- --------------- ----- ----- ---

### I appreciate your commitment to clean air through the implementation ofthe DieselL'M program. 

### Ifyou have any questions or concems, please contact Kerri Fiedler ofmy statfat: (303) 312-6493.

cc: Lee Cook, OTAQ

--------------------------------- ---- 

### C nthia Cody, A
. mg Director Air and Radiation Program

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