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State Implementation Plan (SIP) 

To protect public health, the Clean Air Act (42 U.S.C Section 7401) requires that federal standards be set 

to limit the maximum levels of pollutants in the outdoor air. Each state is responsible for developing plans 

to demonstrate how those standards will be achieved, maintained, and enforced. These plans make up the 

state implementation plan. The plans and rules associated with them are enforced by the state. and. after 

federal approval, they are also federally enforceable. These plans are the framework for each state's 

program to protect the air. 

In areas where the air quality has improved to the point that the National Ambient Air Quality Standards 

are no longer exceeded, the implementation plan remains in effect and a maintenance plan is prepared to 

demonstrate how the air will be kept clean for the next twenty years or longer. These maintenance plans 

also became part of the SIP. 

You can access Utah's SIP the fallowing ways: 

~hcAre a 

• By Subject 

• View rule and SIP changes that are currently out for public comment 

Nonattalnment and Maintenance Area information 

• Air Pollutants and Trend Information 

• CO (Carbon Monoxide) 

• Nonattainment and Maintenance Area Map 

• ~ Particulate Matter CPM1o and PMnl 

Utah DEQ: DAQ: SIP Page 1 of 1 

State Implementation Plan (SIP) 

To protect public health, the Clean Air Act ( 42 U.S. C Section 7 401) requires that federal standards be set to limit the 

maximum levels of pollutants in the outdoor air. Each state is responsible for developing plans to demonstrate how 

those standards will be achieved, maintained, and enforced. These plans make up the state implementation plan. The 

plans and rules associated with them are enforced by the state, and, after federal approval, they are also federally 

enforceable. These plans are the framework for each state's program to protect the air. 

In areas where the air quality has improved to the point that the National Ambient Air Quality Standards are no longer 

exceeded, the implementation plan remains in effect and a maintenance plan is prepared to demonstrate how the air 

will be kept clean for the next twenty years or longer. These maintenance plans also become part of the SIP. 

You can access Utah's SIP the following ways: 

• By Geographic Area 

-""''~·· By Section 

• By Subject 

• View rule and SIP changes that are currently out for public comment. 

Nonattainment and Maintenance Area information 

• Air Pollutants and Trend Information 

• CO (Carbon Monoxide) 

• Nonattainment and Maintenance Area Map 

• Ozone 

• Particulate Matter (PM1o and PM2.sl 

• S02 (Sulfur Oxide) 

Other Plans 

• Designated Facilities 

o Hospital. Medical, Infectious Waste Incinerators 

o Mercury Emissions at Coal-fired Electric Generating Units 

o Municipal Solid Waste Landfi lls 

o Small Municipal Waste Combustion Units 

For more information or questions contact Mark Berger (801-536-0076). 

http:/ /www.airquality. utah.gov/Planning/SIP /index.htm 711 7/201 3 
• 
Utah DEQ: DAQ: SIP: Sections Page 1 of 1 

SIP: By Sections 

Section Title of Section 

Foreword Foreword 

Section I Legal Authority 

Section II Review of New and Modified Air Pollution Sources 

Section Ill Source Surveillance 

Section IV Ambient Air Monitoring Program 

Section V Resources 

Section VI Intergovernmental CooQeration 

Section VII Prevention of Air Pollution Emergency EQisodes 

Section VIII Prevention of Significant Deterioration 

Section IX II Control Measures for Area and Point Sources I 

Section X II Vehicle lnsQection and Maintenance Program I 

Section XI Other Control Measures for Mobile Sources 

Section XII TransQortation Conformity Consultation 

Section XIII Analysis of Plan lmQact 

Section XIV Emission lnventoC;l DeveloQment 

Section XV Utah Air Conservation Act 

Section XVI Public Notification 

Section XVII Visibility Protection 

Section XVIII Demonstration of GEP Stack Height 

Section XIX Small Business Assistance Program 

Section XX Regional Haze 

Section XXI II Diesel lnsQection and Maintenance Program I 

Section XXII General Conformity I 

Section XXIII Interstate TransQort I 

http;/ /www.airquality. utah.gov/Planning/SIP /Section/si -section.htrn 7/17/2013 
• 
UTAH STATE IMPLEMENTATION PLAN 

SECTION XXI 

DIESEL INSPECTION AND MAINTENANCE PROGRAM 

Adopted by the Utah Air Quality Board 

July 12, 1995 
Table of Contents 

A. BACKGROUND ...... .... .. ... .......................................................................................... 1 

B. DIESEL INSPECTION AND MAINTENANCE (1/M) PROGRAM ELEMENTS ............ 2 

1. Diesel/1M Program Implementation .. ............. .................. ... ........ ........ ........ ..... 2 

2. Mandatory Maintenance . ....... ... .. .... ... .. ...... ........... .. .. .... ........ .... .. ... .. ...... ... .. .... 2 

3. Diesel/1M Documentation ............ ................... .. ......... .. ... .... .......... ... ..... ..... .. ... . 3 

4. Diesel/1M Mechanic and Station Certification . ..... .... ....... .. ...... ... ...... .. ... ........ .. 3 

5. Opacity Compliance ............... .. ............................ ... ... ...... ............................... 3 

a. Heavy Duty Diesel Vehicle Opacity Test Requirements . ......... .. .......... 3 

b. Light Duty Diesel Vehicle Opacity Requirements . ..... ............ ... ............ 4 

c. Diesel Vehicle Roadside Opacity Enforcement Requirements .. .. .......... 4 

6. Fleet Self-Certification . ............ ..... ..... ................ ........................................... ... 4 

7. Waiver Provisions ... ... .. .. ... .... ...... .. ... .. ... ......... .. ... .. ....... ...... .... .... .. .................... 5 

8. Additional Strategies . .. ................. ..... .............................................................. 5 

9. Public and Diesel Industry Education . ..... .. ... .. ... ... .. ..... ............ ... ... ... .. .... ..... .... 5 

10. Enforcement. . .......... ..... ............. ....... ............................................................ 5 

11. Diesel/1M Program Effectiveness Evaluation . ..................................... .......... 6 

12. Diesel Vehicle Air Pollution Fee ...... ..... .......... ... ............................. ... ... ... ....... 6 

13. Implementation Schedule ..... ... .. .. .... ..... ...... .. ......... .... .... ... ... .. .. ......... ...... .... ... 6 
APPENDICES 

Appendix 1 Statutory Authorities 

1.a. Utah Code19-2, Utah Air Conservation Act 

1.b. Utah Code 41-6-147, ... Air pollution control devices 

1.c Utah Code 41-6-163.8, Diesel emissions program ... 

Appendix 2. Davis County 

2.a Program Ordinance #05-94, December 15, 1994 

2.b Diesel Emissions Control Fee Ordinance 

Appendix 3. Salt Lake County 

3.a Health Regulations #28, September 1, 1994 

3.b Diesel Emissions Control Fee Standard 

Appendix 4. Utah County 

4.a Diesel Vehicle Emissions Inspection Maintenance Program, 

October 24, 1994 

4.b Diesel Emissions Control Fee Standard 

Appendix 5. Program Equipment and Test Specifications 
UTAH STATE IMPLEMENTATION PLAN 

SECTION XXI 

DIESEL INSPECTION AND MAINTENANCE PROGRAM 

A. BACKGROUND 

1. Davis, Salt Lake, and Utah counties for purposes of PM 10 attainment began phase-in 

of a Diesel Inspection and Maintenance (1/M) Program consistent with the provisions of the 

PM1 0 SIP( Section IX.A) on November 1, 1994. The Davis, Salt Lake, and Utah County Diesel 

1/M ordinances are included as Appendices 2, 3, and 4. 

Diesel 1/M is a relatively new pollution control measure nationwide. New data and methods of 

diesel emission control will be evaluated as they become available. This program will be 

modified as more effective methods are identified. Any changes adopted will be in accordance 

with Utah's commitment to a 20% reduction in diesel particulate. 

2. This program is designed to ensure compliance with Section 41-6-147 (2) and (3). 

(Appendix 1.b) 

3. In addition to the health hazards associated with PM1 0 pollution in general, diesel 

particulate is mutagenic, carcinogenic, and toxic. Furthermore, diesel emissions are generally 

emitted into the breathing zone of the atmosphere. Once inspired into the lung, diesel 

particulates, because of their very small size, are not easily removed by the body. The toxic 

hydrocarbon fraction carried on the elemental carbon fraction is easily released and may react 

with lung tissue or be absorbed into the blood stream. The significant health threat presented 

by excessive levels of diesel PM 10 make adoption of stricter control measures prudent. 

4. This program is being adopted as one element of a strategy to satisfy federal legal 

requirements regarding attainment of PM 10 National Ambient Air Quality Standards. This 

standard is violated currently in Salt Lake and Utah Counties with impact from Davis County. 

Diesel engines contribute significantly to the ambient PM 10 concentration along the Wasatch 

Front, primarily in Davis, Salt Lake, and Utah Counties. As a significant contributor to the 

violations, diesel vehicles must be maintained and operated in such a manner as to minimize 

their particulate emissions. 

5. Owners of gasoline vehicles have been subject to a mandatory inspection and 

maintenance program in Davis, Salt Lake, and Utah counties for a number of years. 

Implementation of a diesel inspection and maintenance program is considered by many to be an 

issue of public perception of equity. 
B. DIESEL INSPECTION AND MAINTENANCE (1/M) PROGRAM ELEMENTS 

1. Diesel/1M Program Implementation. This Program is implemented in counties that 

impact PM1 0 nonattainment areas. Said counties, including Davis, Salt Lake, and Utah 

Counties, will hereafter be referred to as Diesel 1/M Counties. All diesel-fueled vehicles 

registered or principally operated in Diesel 1/M Counties will be required to comply with the 

provisions of this program. Specific details of the Diesel 1/M Program elements were 

established by the Utah 1/M Board consisting of health department representatives of each 

Diesel 1/M County and the Division of Air Quality using input from the public and other interested 

parties. The program is implemented and managed by the local health department in each 

Dieseii/M County. The Dieseii/M Diesel Emission Control Program is dynamic and will allow 

for revision of the elements below, as more effective diesel emission control technologies and 

testing procedures are identified . 

2. Mandatory Maintenance. Proper maintenance of diesel vehicles is paramount to 

minimizing air pollution from these sources. Repair of the emission-related components of 

failed vehicles will be mandatory, to the extent necessary to achieve compliance with opacity 

standards established pursuant to this SIP. The Mobile Source Division of the California Air 

Resources Board conducted a study of smoke opacity inspections of urban transit buses with 

respect to the frequency of emissions related maintenance. They found that frequent periodic 

smoke inspections are more effective than mandatory engine maintenance schedules for 

reducing the number of excessively smoking buses in operation. 

A county-certified Dieseii/M mechanic will certify, by means of a repeated opacity test, that 

mandatory emission-related repairs have brought the vehicle into compliance. Repairs may 

include air and fuel filter replacement, adjustment of primary emission-related engine 

components to the manufacturer's specifications, replacement or repair of any missing or 

damaged manufacturer-installed emission control equipment, and repair or replacement of 

emission-related engine components not functioning per the manufacturer's specifications for 

the number of miles on the odometer. 

3. Diesel/1M Documentation. Documentation of compliance with the Diesel 1/M 

Program requirements consisting of a Diesel 1/M Certificate of Compliance or Waiver will be 

required for annual diesel vehicle registration in Diesel 1/M Counties. 

To facilitate roadside enforcement, proof of Diesel 1/M Program compliance in the form of a 

sticker may be required to be displayed on the vehicle windshield of diesel vehicles principally 

operated in Diesel 1/M Counties. 

Sufficient data to evaluate the effectiveness of the Diesel 1/M Program will be recorded by 

mechanics on Diesel 1/M Reports. These reports will be submitted to the appropriate Diesel 1/M 

County health department. An automated and/or computerized data management system will 

be utilized. Standardized data elements are specified in each county regulation or ordinance 

(Appendices 2, 3, and 4) and in the Utah 1/M Program Equipment and Test Specifications 

(Appendix 5). 

4. Diesel/1M Mechanic and Station Certification. Diesel 1/M County health departments 

will certify Diesel 1/M mechanics and stations upon their demonstration of adequate training, 
skill, and resources. Specific requirements for Diesel 1/M certification are explicitly defined by 

each Dieseii/M County regulation or ordinance (Appendices 2, 3, and 4). 

Diesel 1/M Counties will provide Diesel 1/M Program training to mechanics, diesel repair facility 

managers, and other interested parties. The training will include Diesel 1/M test procedures, 

visual opacity training, a description of the components of diesel emissions and their impact on 

human health and the environment, technical aspects of repair specific to reduction of diesel 

emission opacity, mechanic and station Dieseii/M program responsibilities and Diesel 1/M 

Program safety requirements. 

All Diesel 1/M County-certified diesel emission control mechanics and stations will be subjected 

to at least quarterly audits and one covert audit each year. Evidence of inadequacy may result 

in more frequent audits of individual mechanics or stations. An appropriate substitute for covert 

audit of self-certifying fleet mechanics and stations will be included in the program. Violation of 

the Diesel 1/M Program rules may result in revocation or suspension of certification. 

5. Opacity Compliance 

a. Heavy Duty Diesel Vehicle Opacity Test Requirements. Heavy duty diesel vehicle 

compliance with diesel emission opacity standards will be determined for purposes of 

registration as specified in the Utah Dieseii/M Program Equipment and Test Specifications 

(Appendix 5). The test consists of measuring exhaust smoke levels as the accelerator pedal is 

rapidly depressed while the vehicle transmission is disengaged. Opacity will be measured by 

means of an opacity meter and recorded as a 500-millisecond running average on a recording 

device. 

A cutpoint of 40% opacity has been shown by the California Air Resources Board to result in no 

greater than 5% errors of commission or omission at low elevations. The Society of Automotive 

Engineers is currently conducting high altitude studies to correlate opacity with elevation. 

Utah's Diesel 1/M Program started with a cutpoint of 80% opacity for heavy duty engines. After 

the high altitude studies are complete the cutpoint may be changed. The cutpoints will be 

established and revised in conjunction with the fail rate to achieve a 20% reduction in diesel 

particulate pollution. The peak smoke certification value was found to be subject to a standard 

deviation of 10% when production variability within the engine family , deterioration factors , test 

variability, and state of maintenance were considered. 

A limited number of engine families were certified with relatively high peak smoke opacities and 

may be incapable of achieving 500 milli-second running average opacities below 80%at high 

elevations. The Diesel 1/M Counties will establish a procedure to allow a higher opacity 

standard for these engines families . The owner must submit proof of engine peak smoke 

certification, make, and horsepower to the appropriate Dieseii/M County office in order to be 

considered for a higher opacity standard. 

b. Light Duty Diesel Vehicle Opacity Requirements. Light duty diesel vehicle exhaust 

opacity will be measured under load on a dynamometer with an opacity meter and recording 

device specified in Utah Diesel 1/M Program Equipment and Test Specification (Appendix 5). 

An opacity cutpoint for light duty diesel vehicles will be established at a value sufficient to 

achieve a failure rate sufficient to ensure a 10% diesel particulate reduction . Specifications for 

the test, the opacity meter, the recording device, the dynamometer, safety requirements, and 

test documentation are specified in Appendix 5 of Section XXI. 
c. Diesel Vehicle Roadside Opacity Enforcement Requirements. Roadside opacity 

compliance inspection/evaluation and citation of violators by law enforcement officers would be 

most effectively accomplished by means of a modified EPA Method 9 visual 

inspection/evaluation to be designed by the Executive Secretary. The Division of Air Quality will 

seek a Memorandum of Understanding (MOU) with State and local law enforcement agencies to 

enforce the roadside opacity limits. Training would be provided to law enforcement officers, 

certified Diesel 1/M mechanics, and Diesel 1/M auditors for performing this compliance function. 

6. Fleet Self-Certification. Fleets of 25 or more heavy duty diesel vehicles may be selfcertified if both the fleet mechanic doing the inspections and the facility is Diesel 1/M Program 

certified. Self-certifying fleets will be required to perform opacity inspections with an opacity 

meter and recording device that meets Diesel 1/M Program specifications (Appendix 5). 

Recording devices from the inspections will be maintained and subject to inspection by county 

staff during any audits. All fleet stations and mechanics certified to perform Diesel 1/M 

self-certification will be subject to regular inspections by appropriate county auditors. During 

self-certifying fleet audits, county auditors will review vehicle emissions inspection and 

maintenance records and inspect a representative sample of vehicles with an opacity meter to 

verify compliance. Self-certifying fleet vehicles will also be subject to a quarterly test with visual 

evaluation of smoke opacity. Vehicles that exceed the opacity limit will be remeasured with an 

opacity meter and repaired if the meter confirms that the exhaust opacity exceeds the opacity 

standard. Self-certifying stations will maintain records of specific repairs performed to bring 

failed vehicles into compliance. As with any certified mechanic or station, violation of the Diesel 

1/M Program rules may result in revocation or suspension of certification. Operation of 

self-certified fleet vehicles in violation of Section 41-6-14 7 will be considered a violation of 

Section XXI . 

7. Waiver Provisions. Waivers will be issued only in the absence of evidence of 

tampering with emission control devices installed by the manufacturer. A waiver may be issued 

on a one-time basis only. A minimum of $500 must be spent on emissions related repairs 

without attaining compliance for waiver eligibility on a light duty diesel vehicle. A minimum of 

$1500 must be spent on emissions related repairs without attaining compliance for waiver 

eligibility on a heavy duty diesel vehicle. The Diesel 1/M Counties will establish procedures to 

ensure that waivers are kept to an absolute minimum. 

8. Additional Strategies. DAQ staff will evaluate and propose adoption, as appropriate, 

of additional strategies regarding fuel specifications, emission control technology retrofitting, 

locomotive emission control requirements, idling ordinances, participation by commuters from 

outside the Diesel 1/M Counties, and alternative fuels. DAQ staff may submit to appropriate 

federal authorities the recommendation that federal standards regarding control of diesel 

emissions from interstate traffic be adopted. 

9. Public and Diesel Industry Education. Public education regarding Diesel 1/M Program 

requirements and the anticipated environmental benefits will be provided to diesel vehicle 

owners. A period of intense public education will precede roadside enforcement of the opacity 

rules. The education effort will include informing drivers of operating practices and the fuel 

types that increase pollution and should be avoided. A written summary of the new Diesel liM 

Program will be provided to diesel industry organizations with encouragement for inclusion of 

the information in their publications. A resource, such as the telephone number of county 1/M 

technical centers, for obtaining additional information will be provided. 
10. Enforcement. The ExecutiveSecretary will encourage aggressive enforcement of 

Section 41-6-147 by law enforcement agencies. Pursuant to Section 41-6-147(Appendix 1.b), 

motor vehicles are required to comply with emissions requirements. The Utah Highway Patrol 

and other law enforcement agencies are authorized to cite drivers of vehicles emitting excess 

diesel smoke. 

Notice of diesel opacity violations will be provided to appropriate railroad offices following 

observation of excessive locomotive exhaust by an observer that has successfully completed 

the DAQ smoke evaluation school. A mechanism to verify that the locomotive is repaired to 

compliance will be established. 

County Diesel 1/M auditors may on a random basis subject heavy duty diesel vehicles operated 

in that county to an opacity test conducted at their base of operation. Vehicles for which the 

county Diesel 1/M office has received complaints of excessively smoking diesel vehicles will be 

subject to an opacity test of the vehicle(s) in question by the auditor. Owners of vehicles found 

to be in violation of the standard will be penalized as noted below. 

The Utah Air Conservation Act 19-2-115 (Appendix 1.a) provides for imposition of penalties of 

up to $10,000 per violation of the Act. Penalties for violation of this Program may be levied by 

authority of the Utah Air Quality Board Penalty Policy, R307 -4, under which violation of 

automobile emission standards and requirements is a category D violation and may result in a 

penalty of up to $299 per violation. Diesel liM Counties will evaluate the penalty policy with 

respect to the Diesel 1/M Program. Penalties should be sufficient to ensure that it is cheaper to 

fix the vehicle than to risk citation. Repair of smoking diesels, especially heavy duty vehicles~ 

frequently exceeds $500 and may cost as much as $10,000. Should Dieseii/M Counties 

demonstrate the necessity for higher penalties, they will request that the Utah Air Quality Board 

consider revision of the penalty policy accordingly. However, the goal of the Dieseii/M 

Program is to reduce emissions by inspection and maintenance of vehicles, only assessing 

penalties when necessary. 

The Division of Air Quality and Diesel 1/M Counties will initiate an effort to obtain enforcement 

support from various law enforcement agencies. Diesel 1/M County ordinances and regulations 

authorizing their Diesel 1/M Program include provisions that provide for county enforcement of 

the requirements of said legal instruments. 

A significant portion of the heavy duty diesel vehicles operated in Utah's PM 10 non-attainment 

counties are registered outside the state. The Division of Air Quality will initiate an effort with 

the Department of Transportation, the Highway Patrol, and Diesel 1/M Counties to cooperatively 

develop and conduct a diesel emission roadside and port-of-entry inspection program with 

effective and reasonable penalties. The purpose of these inspections will be to identify and 

subsequently force repair of heavy duty diesel-fueled vehicles that are emitting smoke in excess 

of Utah's opacity statute and rules. 

11 . Diesel/1M Program Effectiveness Evaluation. Utah initiated an effort to develop a 

national diesel emission control standards in 1992. That effort resulted in formation of a Society 

of Engineers committee to develop a test and the equipment specifications for diesel emission 

control. The committee has met for two years and is nearly finished with the specifications, SAE 

J1667. Peer review and field verification are all that remain. The field work is being conducted. 

The Utah 1/M Program Equipment and Test Specifications (Appendix 5) are based on SAE 

J1667. EPA is also represented on the committee. 
The Division of Air Quality, in conjuction with the Diesel 1/M Counties, will establish a method to 

support anticipated emission reductions achieved by the Diesel 1/M Program. The evaluation 

will consist of an analysis of data submitted on Diesel 1/M Maintenance Reports, a field study to 

correlate actual opacity reductions with the required inspection and maintenance program 

emissions reductions, modeling evaluation (if available), and actual monitoring station data. A 

summary of an annual evaluation of current diesel control technology and strategies and 

recommended Diesel 1/M Program changes will be submitted to the Executive Director by Diesel 

1/M County Health Departments by August 1 of each year after their Diesel 1/M regulation or 

ordinance is adopted. The program will be reviewed and updated in light of the annual 

evaluation as deemed effective and reasonable by Diesel 1/M County program managers. 

12. Diesel Vehicle Air Pollution Fee. The Diesel 1/M counties began assessing an 

annual Air Pollution Fee of $10 payable upon registration of a diesel vehicle in a Diesel 1/M 

county in 1991 to be used by the Diesel 1/M counties to develop and implement the Diesel 1/M 

Program. 

13. Implementation Schedule 

June 8, 1990 .. . Utah 1/M Board Preparation of an Initial Draft of the Diesel 1/M Program Elements 

June 13, 1990 ... Draft Diesel 1/M Program Elements Ready For UACC 

June 22, 1990 ... Air Conservation Committee Consider the Draft Elements for Public Hearing 

Aug 10, 1990 .. . Utah 1/M Board Submit Draft of Diesei i/M Program to BAQ 

Aug 15, 1990 ... Public Hearings for PM1 0 SIP Including Draft Diesel 1/M Program 

Sept 15, 1990 .. . Utah 1/M Board Finalizes proposed Diesel liM Program for Submission to UACC 

and county commissions 

Sept 30, 1990 .. . Diesel 1/M County Commissions Commit to Implement a Diesel 1/M Program by 

July 1, 1993 that will reduce ambient diesel particulate by at least 20% whether by the test 

methods described in section b) of the UTAH DIESEL 1/M PROGRAM portion of the 

PM1 0 SIP or more effective procedures that may be identified during the Implementation 

Evaluation to be conducted by the Utah 1/M Board between Sept 30, 1990 and Sept 30, 

1991 . 

Oct 1, 1990 ... PM10 SIP-Regulations for Utah County and parts of Salt Lake and Davis Counties are 

Sent to EPA for Approval 

Nov 1, 1990 ... Begin Diesel 1/M Pilot Study Program (if funds available) and initiate Public and Diesel 

Industry Education Program 

July 1, 1991 ... Written Notification to Diesel Industry Organizations and Publications 

Jan 1, 1991 ... Diesel liM Counties Begin Assessing $10 Air Pollution Control Fee Upon Every DieselPowered Motor Vehicle Registered 

Sept 1, 1994 

Oct 24, 1994 

Salt Lake County Diesel 1/M Regulation adopted 

Utah County Diesel 1/M Regulation adopted 

IIDTmiH IIIII.. P I 
Dec 15, 1994 Davis County Diesel 1/M Ordinance adopted 

Oct 30, 1991 .. . Dieseii/M Program Orientation Available to Law Enforcement Agencies 

Nov 1, 1991 ... Enforcement of Opacity Limits by Law Enforcement Officers 

May 9, 1992 Diesel meeting at North American Motor Vehicle Emissions Control Conference 

(NAMVECC) to discuss national diesel emission control equipment and test standards 

Nov 1, 1994 .. . Fleet and Public Diesel 1/M Program Provisions Become Effective 

The Diesel 1/M Program regulations, ordinances, and requirements specified in Section XXI 

shall continue until a maintenance plan without a Diesel 1/M program is approved in accordance 

with Section 175 of the Clean Air Act as amended.