State of Utah 

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 2 7 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 

Dear Ms Videtich: 

We were surprised and disappointed by the February 1, 2007letter from Cindy Cody 

requesting we withdraw Utah's February 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 of your staff and EPA's Office of Transportation Air Quality (OTAQ), to discuss 

Utah's February 6, 1996, Diesel I/M SIP submittal. At the conclusion of the 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/M program 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 

PM reductions. 

• EPA would provide Utah with a strong letter endorsing the continuance of our 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.gov 
DAQ-012-07 

Page 2 

Utah has led the nation in establishing an effective diesel 11M program for heavy-duty and 

light-duty diesel vehicles. liM jurisdictions 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 of the 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 of a variety of control measures, including further controls on diesel 

vehicles. Withdrawing our Diesel 11M SIP will not facilitate this process. Our diesel 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 and priorities and would send an inconsistent message to the public 

and jeopardize our remaining diesel 11M programs. 

While EPA approved the inclusion of Utah's diesel 11M program in its approval of Utah's 

1991 PM SIP submittal, this SIP was superseded in Utah County with EPA's approval of the 

Utah County Interim PM SIP in 2002. Under EPA's guidance, the diesel 11M program was 

not included as a control measure in Utah's 2005 PM Maintenance Plan. Upon EPA approval 

of the 2005 PM Maintenance Plan, the diesel 11M program will no longer remain as a SIP 

strengthening control measure in Utah and the program will likely be terminated. 

Therefore, we can not concur with the region's request that we withdraw our February 6, 1996 

Diesel liM SIP submittal and we request final rulemaking on Utah's submittal. We would 

also appreciate better communication 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 of Air 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 a better understanding of Utah'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. 

Please refer to 59 FR35036 or 57 FR 60149 for a more detailed description in the notice 

of proposed rulemaking. At this time, we do not have a technical basis for quantifying 

the particulate matter benefits of an opacity liM program. As a result, we are not able to 

assign a specific level of credit in MOBILE6 to such programs. Nevertheless, it is likely 

that finding and fixing smoking vehicles results in net PM benefits in the real world. 

As we discussed on the call, technology is under development that may allow for 

accurate measurement of PM emissions from diesel vehicles in an 1/M setting. Such 

technology could lead to development of precise quantification of die5eli/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 of the diesel 

1/M SIP . 

. - --- --- --- --- --- ----- --- --- -------- . ---------------------------------- --------------- ----- ----- ---
I appreciate your commitment to clean air through the implementation of the 

DieselL'M program. If you have any questions or concems, please contact Kerri Fiedler 

of my statf at: (303) 312-6493. 

cc: Lee Cook, OT AQ 

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

C nthia Cody, A . mg Director 

Air and Radiation Program 

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