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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 79, 80, 85, 86, 600, 1036, 1037, 1039, 1042, 1048, 1054, 1065, and 1066

[EPA–HQ–OAR–2011–0135; FRL_XXXX-X]

RIN 2060-AQ86

Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and 

Fuel Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final Rule.

SUMMARY: This action establishes more stringent vehicle emissions standards and will 

reduce the sulfur content of gasoline beginning in 2017, as part of a systems approach to 

addressing the impacts of motor vehicles and fuels on air quality and public health. The 

gasoline sulfur standard will make emission control systems more effective for both 

existing and new vehicles, and will enable more stringent vehicle emissions standards. 

The vehicle standards will reduce both tailpipe and evaporative emissions from passenger 

cars, light-duty trucks, medium-duty passenger vehicles, and some heavy-duty vehicles. 

This will result in significant reductions in pollutants such as ozone, particulate matter, 

and air toxics across the country and help state and local agencies in their efforts to attain 

and maintain health-based National Ambient Air Quality Standards. Motor vehicles are 

an important source of exposure to air pollution both regionally and near roads. These 

vehicle standards are intended to harmonize with California’s Low Emission Vehicle 

program, thus creating a federal vehicle emissions program that will allow automakers to 

sell the same vehicles in all 50 states. The vehicle standards will be implemented over 

the same timeframe as the greenhouse gas/fuel efficiency standards for light-duty

vehicles (promulgated by EPA and the National Highway Safety Administration in 

2012), as part of a comprehensive approach toward regulating emissions from motor 

vehicles. 

DATES: This final rule is effective on [Insert date 60 days after publication in the 

Federal Register]. The incorporation by reference of certain publications listed in this 

regulation is approved by the Director of the Federal Register as of [Insert date 60 days 

after publication in the Federal Register].

ADDRESSES: EPA has established a docket for this action under Docket ID No. EPA–

HQ–OAR–2011–0135. All documents in the docket are listed on the 

www.regulations.gov web site. Although listed in the index, some information is not 

publicly available, e.g., CBI or other information whose disclosure is restricted by statute. 

Certain other material, such as copyrighted material, is not placed on the Internet and will 

be publicly available only in hard copy form. Publicly available docket materials are 
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available either electronically in www.regulations.gov or in hard copy at the Air and 

Radiation Docket and Information Center, EPA/DC, EPA West, Room 3334, 1301 

Constitution Ave., NW, Washington, DC. The Public Reading Room is open from 8:30 

a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone 

number for the Public Reading Room is (202) 566-1744, and the telephone number for 

the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: JoNell Iffland, Office of 

Transportation and Air Quality, Assessment and Standards Division (ASD), 

Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor MI 48105; 

Telephone number: (734) 214-4454; Fax number: (734) 214-4816; E-mail address: 

iffland.jonell@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

Entities potentially affected by this rule include gasoline refiners and importers, 

ethanol producers, ethanol denaturant producers, butane and pentane producers, gasoline 

additive manufacturers, transmix processors, terminals and fuel distributors, light-duty

vehicle manufacturers, independent commercial importers, alternative fuel converters, 

and manufacturers and converters of vehicles between 8,500 and 14,000 lbs gross vehicle 

weight rating (GVWR). 

Potentially regulated categories include:

Category NAICSa Code SIC

b Code Examples of Potentially Affected Entities

Industry 324110 2911 Petroleum refineries (including importers)

Industry 325110 2869 Butane and pentane manufacturers

Industry 325193 2869 Ethyl alcohol manufacturing

Industry 324110,

211112

2911,

1321

Ethanol denaturant manufacturers

Industry 211112 1321 Natural gas liquids extraction and fractionation

Industry 325199 2869 Other basic organic chemical manufacturing

Industry 486910 4613 Natural gas liquids pipelines, refined petroleum 

products pipelines

Industry 424690 5169 Chemical and allied products merchant 

wholesalers

Industry 325199 2869 Manufacturers of gasoline additives

Industry 424710 5171 Petroleum bulk stations and terminals.

Industry 493190 4226 Other warehousing and storage- bulk petroleum 

storage

Industry 336111, 3711 Light-duty vehicle and light-duty truck 
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336112 manufacturers

Industry 811111, 

811112, 

811198

7538, 

7533, 

7534 Independent commercial importers

Industry 335312,

336312,

336322,

336399,

811198

3621, 

3714, 

3519, 

3599, 

7534 Alternative fuel converters

Industry 333618,

336120,

336211,

336312

3699, 

3711, 

3713, 

3714

On-highway heavy-duty engine & vehicle 

(>8,500 lbs GVWR) manufacturers

a North American Industry Classification System (NAICS).

b

Standard Industrial Classification (SIC).

This table is not intended to be exhaustive, but rather provides a guide for readers 

regarding entities likely to be regulated by this action. This table lists the types of entities 

that EPA is now aware could potentially be regulated by this action. Other types of 

entities not listed in the table could also be regulated. To determine whether your 

activities are regulated by this action, you should carefully examine the applicability

criteria in 40 CFR parts 79, 80, 85, 86, 600, 1036, 1065, and 1066 and the referenced 

regulations. If you have any questions regarding the applicability of this action to a 

particular entity, consult the person listed in the preceding FOR FURTHER 

INFORMATION CONTACT section.

B. Did EPA Conduct a Peer Review before Issuing this Action?

This regulatory action was supported by influential scientific information. 

Therefore, EPA conducted peer reviews in accordance with OMB’s Final Information 

Quality Bulletin for Peer Review. EPA conducted several peer reviews in connection 

with data supporting the Tier 3 program, including new research on the effects of fuel 

properties changes (including sulfur effects) on exhaust and evaporative emissions of 

Tier 2 vehicles. The refinery-by-refinery cost model was also peer reviewed. The peer 

review reports are located in the docket for today's action, as well as the agency's 

response to the peer review comments.

TABLE OF CONTENTS

I. EXECUTIVE SUMMARY AND PROGRAM OVERVIEW

A. Introduction

B. Overview of the Tier 3 Program

1. Major Public Comments and Key Changes from the Proposal

2. Key Components of the Tier 3 Program
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C. What Will the Impacts of the Standards Be?

II. WHY IS EPA TAKING THIS ACTION?

A. Basis for Action under the Clean Air Act

1. Clean Air Act Section 202

2. Clean Air Act Section 211

B. Overview of Public Health Impacts of Motor Vehicles and Fuels

1. Ozone

2. Particulate Matter

3. Oxides of Nitrogen and Sulfur

4. Carbon Monoxide

5. Mobile Source Air Toxics

6. Near-Roadway Pollution

7. Environmental Impacts of Motor Vehicles and Fuels

III. HOW WOULD THIS RULE REDUCE EMISSIONS AND AIR 

POLLUTION?

A. Effects of the Vehicle and Fuel Changes on Mobile Source Emissions

1. How Do Vehicles Produce the Emissions Addressed in this Action?

2. How Will the Changes to Gasoline Sulfur Content Affect Vehicle Emissions?

B. How Will Emissions Be Reduced?

1. NOX

2. VOC

3. CO

4. Direct PM2.5

5. Air Toxics

6. SO2

7. Greenhouse Gases

C. How Will Air Pollution Be Reduced?

1. Ozone

2. Particulate Matter

3. Nitrogen Dioxide

4. Air Toxics
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5. Visibility

6. Nitrogen and Sulfur Deposition

7. Environmental Justice

IV. VEHICLE EMISSIONS PROGRAM

A. Tier 3 Tailpipe Emission Standards for Light-Duty Vehicles, Light-Duty 

Trucks, and Medium-Duty Passenger Vehicles

1. How the Tier 3 Program is Harmonized with the California LEV III 

Program

2. Summary of the Tier 3 FTP and SFTP Tailpipe Standards

3. FTP Standards

4. SFTP Standards

5. Feasibility of the NMOG+NOX and PM Standards

6. Impact of Gasoline Sulfur Control on the Effectiveness of the Vehicle 

Emission Standards

7. Other Provisions

B. Tailpipe Emissions Standards for Heavy-Duty Vehicles

1. Overview and Scope of Vehicles Regulated

2. HDV Exhaust Emissions Standards

3. Supplemental FTP Standards for HDVs

4. HDV Emissions Averaging, Banking, and Trading

5. Feasibility of HDV Standards

6. Other HDV Provisions

C. Evaporative Emissions Standards

1. Tier 3 Evaporative Emission Standards

2. Program Structure and Implementation Flexibilities

3. Technological Feasibility

4. Heavy-Duty Gasoline Vehicle (HDGV) Requirements

5. Evaporative Emission Requirements for FFVs

6. Test Procedures and Certification Test Fuel

D. Improvements to In-Use Performance of Fuel Vapor Control Systems

1. Reasons for Adding a Leak Test Standard

2. Nature, Scope and Timing of Leak Standard
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3. Leak Standard Test Procedure

4. Certification and Compliance

a. In-Use Verification Program (IUVP) Requirements for the Leak Standard

E. Onboard Diagnostic System Requirements

1. Onboard Diagnostic (OBD) System Regulation Changes - Timing

2. Revisions to EPA OBD Regulatory Requirements

3. Provisions for Emergency Vehicles

4. Future Considerations

F. Emissions Test Fuel

1. Gasoline Emissions Test Fuel: Ethanol Content and Volatility

2. Other Gasoline Emissions Test Fuel Specifications

3. Flexible Fuel Vehicle Exhaust Emissions Test Fuel

4. Implementation Schedule

5. Implications of Emission Test Fuel Changes on CAFE Standards, GHG 

Standards, and Fuel Economy Labels

6. Consideration of Test Fuel for Nonroad Engines and Highway Motorcycles

7. CNG and LPG Emissions Test Fuel Specifications

G. Small Business Provisions

1. Lead Time and Relaxed Interim Standards

2. Assigned Deterioration Factors

3. Reduced Testing Burden and OBD Requirements

4. Hardship Relief

5. Eligibility for the Flexibilities

H. Compliance Provisions

1. Exhaust Emission Test Procedures

2. Reduced Test Burden

3. Miscellaneous Provisions

4. Manufacturer In-Use Verification Program (IUVP) Requirements

V. FUEL PROGRAM

A. Overview

1. Background
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2. Summary of Final Tier 3 Fuel Program Standards

B. Annual Average Sulfur Standard

C. Per-Gallon Sulfur Caps

1. Standards

2. Requirements for Gasoline Additives

D. Averaging, Banking, and Trading Program

1. How Will the ABT Program Assist with Compliance?

2. ABT Modeling

3. Eligibility

4. Credit Generation and Use

5. Credit Trading Provisions

6. ABT Provisions for Small Refiners and Small Volume Refineries

7. Deficit Carryforward

E. Additional Program Flexibilities

1. Regulatory Flexibility Provisions

2. Provisions for Refiners Facing Hardship Situations

F. Compliance Provisions

1. Registration, Reporting, and Recordkeeping Requirements

2. Sampling and Testing Requirements

3. Small Refiner Compliance

4. Small Volume Refinery Compliance

5. Attest Engagements, Violations, and Penalties

6. Special Fuel Provisions and Exemptions

G. Standards for Oxygenates (Including Denatured Fuel Ethanol) and Certified 

Ethanol Denaturants

H. Standards for Fuel Used in Flexible Fueled Vehicles

I. Sulfur Standards for Purity Butane and Purity Pentane Streams Blended into 

Gasoline

J. Standards for CNG and LPG

K. Refinery Air Permitting Interactions

1. Proposal

2. Updated Assessment of Tier 3 Refinery Changes and Permitting Implications
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3. Comments and Responses

L. Refinery Feasibility

1. Comments Received

2. Is it Feasible for Refiners to Comply with a 10 ppm Average Sulfur 

Standard?

3. Can Refiners Meet the January 1, 2017 Start Date?

M. Statutory Authority for Tier 3 Fuel Controls

1. Section 211(c)(1)(A)

2. Section 211(c)(1)(B)

3. Section 211(c)(2)(B)

4. Section 211(c)(2)(C)

VI. TECHNICAL AMENDMENTS AND REGULATORY STREAMLINING

A. Fuel Program Amendments

1. Fuels Program Regulatory Streamlining

2. Performance-Based Measurement Systems (PBMS)

3. Downstream Pentane Blending

4. Acceptance of Top Tier Deposit Control Test Data

5. Potential Broader Regulatory Streamlining Through Program Restructuring

B. Engine, Vehicle and Equipment Programs Amendments

1. Fuel Economy Labeling

2. Removing Obsolete Regulatory Text

3. Motorcycle Driving Schedules

4. Updating Reference Procedures

VII. WHAT ARE THE COST IMPACTS OF THE RULE?

A. Estimated Costs of the Vehicle Standards

1. What Changes Have Been Made to Vehicle Program Costs Since Proposal?

2. Summary of Vehicle Program Costs

B. Estimated Costs of the Fuel Program

1. Overview

2. Methodology

3. Fuel Program Costs
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4. Other Cost Estimates

C. Summary of Program Costs

VIII. WHAT ARE THE ESTIMATED BENEFITS OF THE RULE?

A. Overview

B. Quantified Human Health Impacts

C. Monetized Benefits

D. What are the Limitations of the Benefits Analysis?

E. Illustrative Analysis of Estimated Monetized Impacts Associated with the Rule 

in 2018

IX. ALTERNATIVES ANALYSIS

A. Vehicle Emission Standards

1. Shorter NMOG+NOX Standard Phase-in

2. NMOG+NOX Standards Phase-in and Early Tier 3 Credits

3. NMOG+NOX Standards

4. PM Standards

5. Higher Ethanol Content of Emissions Test Fuel

B. Fuel Sulfur Standards

1. Annual Average Sulfur Standard

2. Refinery Gate Sulfur Cap

C. Program Start Date

X. ECONOMIC IMPACT ANALYSIS

A. Introduction

B. Vehicle Sales Impacts

C. Impacts on Petroleum Refinery Sector Production

D. Employment Impacts

1. Employment Impacts in the Auto Sector

2. Refinery Employment Impacts

XI. PUBLIC PARTICIPATION

XII. STATUTORY AND EXECUTIVE ORDER REVIEWS

A. Executive Order 12866: Regulatory Planning and Review and Executive 

Order 13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act
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C. Regulatory Flexibility Act

1. Overview

2. Background

3. Reason for Today’s Rule

4. Legal Basis for Agency Action

5. Summary of Potentially Affected Small Entities

6. Reporting, Recordkeeping, and Compliance

7. Related Federal Rules

8. Steps Taken to Minimize the Economic Impact on Small Entities

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with Indian Tribal 

Governments

G. Executive Order 13045: Protection of Children from Environmental Health 

Risks and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations That Significantly 

Affect Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address Environmental Justice in 

Minority Populations and Low-Income Populations

K. Congressional Review Act

XIII. STATUTORY PROVISIONS AND LEGAL AUTHORITY

I. Executive Summary and Program Overview 

A. Introduction

In this action, EPA is finalizing a major program designed to reduce air pollution 

from passenger cars and trucks. This program includes new standards for both vehicle 

emissions and the sulfur content of gasoline, considering the vehicle and its fuel as an 

integrated system. We refer to this program as the “Tier 3” vehicle and fuel standards. 

This rule is part of a comprehensive approach to address the impacts of motor 

vehicles on air quality and public health. Over 149 million Americans are currently 

experiencing unhealthy levels of air pollution, which are linked with respiratory and 
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cardiovascular problems and other adverse health impacts that lead to increased 

medication use, hospital admissions, emergency department visits, and premature 

mortality.

1

 Motor vehicles are a particularly important source of exposure to air 

pollution, especially in urban areas. By 2018, we project that in many areas that are not 

attaining health-based ambient air quality standards (i.e., “nonattainment areas”), 

passenger cars and light trucks will contribute 10-25 percent of total nitrogen oxides 

(NOX) emissions, 15-30 percent of total volatile organic compound (VOC) emissions, 

and 5-10 percent of total direct particulate matter (PM2.5) emissions.2 These compounds 

form ozone, PM, and other air pollutants, whose health and environmental effects are 

described in more detail in Section II. Cars and light trucks also continue to be a 

significant contributor to air pollution directly near roads, with gasoline vehicles 

accounting for more than 50 percent of near-road concentrations of some criteria and 

toxic pollutants.3 More than 50 million people live, work, or go to school in close 

proximity to high-traffic roadways, and the average American spends more than one hour 

traveling along roads each day.

4,5 Over 80 percent of daily trips use personal vehicles.6

The standards set forth in this rule will significantly reduce levels of multiple air 

pollutants (such as ambient levels of ozone, PM, nitrogen dioxide (NO2), and mobile 

source air toxics (MSATs)) across the country, with immediate benefits from the gasoline 

sulfur control standards starting in 2017. These reductions will help state and local 

agencies in their effort to attain and maintain health-based National Ambient Air Quality

Standards (NAAQS). Few other national strategies exist that will deliver the same 

magnitude of multi-pollutant reductions and associated public health protection that is 

projected to result from the Tier 3 standards. Without this action to reduce nationwide 

motor vehicle emissions, areas would have to adopt other, less cost-effective measures to 

reduce emissions from other sources under their state or local authority. In the absence of 

 

1 The 149 million represents people living in O3, PM2.5, PM10, and SO2 nonattainment areas. Data come 

from Summary Nonattainment Area Population Exposure Report, current as of December 5, 2013 at: 

http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR-2011-0135.

2 Mobile source contributions derived from inventories developed for this rule. For more information on 

these inventories see the Emissions Inventory Technical Support Document (TSD) for the final Tier 3 Rule, 

Docket ID No. EPA-HQ-OAR-2011-0135.

3

For example, see Fujita, E.M; Campbell, D.E.; Zielinska, B.; Arnott, W.P.; Chow, J.C. (2011) 

Concentrations of Air Toxics in Motor Vehicle-Dominated Environments. Health Effects Institute 

Research Report 156. Available at http://www.healtheffects.org

4 U.S. Census Bureau (2011). Current Housing Reports, Series H150/09, American Housing Survey for the 

United States: 2009. U.S. Government Printing Office, Washington, DC. Available at 

http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html. (Note that this survey includes estimates 

of homes within 300 feet of highways with four or more lanes, railroads, and airports.)

5 Drago, R. (2011). Secondary activities in the 2006 American Time Use Survey. U.S. Bureau of Labor 

Statistics Working Paper 446. Available at http://www.bls.gov

6

 Santos, A.; McGuckin, N, Yukiko Nakamoto, H.; Gray, D.; Liss, S. (2011) Summary of Travel Trends: 

2009 National Household Travel Survey. Federal Highway Administration report no FHWA-PL-11-022. 

Available at http://nhts.ornl.gov/publications.shtml.
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additional controls, certain areas would continue to have ambient ozone concentrations 

exceeding the NAAQS in the future. See Section III.C for more details.

The Clean Air Act authorizes EPA to establish emissions standards for motor 

vehicles to address air pollution that may reasonably be anticipated to endanger public 

health or welfare (section 202). EPA also has authority to establish fuel controls to 

address such air pollution (section 211). These statutory authorities are described in 

Section II.A. 

The vehicle and gasoline sulfur standards we are finalizing represent a “systems 

approach” to reducing vehicle exhaust and evaporative emissions by addressing the 

vehicle and fuel as a system. The systems approach enables emission reductions that are 

both technologically feasible and cost-effective beyond what would be possible looking 

at vehicle and fuel standards in isolation. We first applied such an approach with our 

Tier 2 vehicle/gasoline sulfur standards (finalized in 2000).7 We believe that a similar 

approach for the Tier 3 standards is a cost-effective way to achieve substantial additional 

emissions reductions. 

The Tier 3 standards include new light- and heavy-duty vehicle emission 

standards for exhaust emissions of VOC (specifically, non-methane organic gases, or 

NMOG), NOX, and PM, as well as new evaporative emissions standards. The fully

phased-in standards for light-duty vehicle, light-duty truck, and medium-duty passenger 

vehicle tailpipe emissions are an 80 percent reduction in fleet average NMOG+NOX

compared to current standards, and a 70 percent reduction in per-vehicle PM standards. 

The fully phased-in Tier 3 heavy-duty vehicle tailpipe emissions standards for

NMOG+NOX and PM are on the order of 60 percent lower than current standards. 

Finally, the fully phased-in evaporative emissions standards represent a 50 percent 

reduction from current standards.

The vehicle emission standards, combined with the reduction of gasoline sulfur 

content from the current 30 parts per million (ppm) average down to a 10 ppm average, 

will result in dramatic emissions reductions for NOX, VOC, direct PM2.5, carbon 

monoxide (CO) and air toxics. For example, in 2030, when Tier 3 vehicles will make up 

the majority of the fleet as well as vehicle miles traveled, NOX and VOC emissions from 

on-highway vehicles will be reduced by about 21 percent, and CO emissions will be 

reduced by about 24 percent. National emissions of many air toxics from on-highway

vehicles will also be reduced by 10 to nearly 30 percent. Reductions will continue 

beyond 2030 as more of the fleet is composed of vehicles meeting the fully phased-in 

Tier 3 standards. For example, the Tier 3 program will reduce on-highway emissions of 

NOX and VOC nearly 31 percent by 2050, when vehicles meeting the fully phased-in Tier 

3 standards will comprise almost the entire fleet.

 

7

65 FR 6698 (February 10, 2000)
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Gasoline vehicles depend to a great degree on catalytic converters to reduce levels 

of pollutants in their exhaust, including NMOG and NOX, as well as PM (specifically, the 

volatile hydrocarbon fraction), CO, and most air toxics. The catalytic converters become 

significantly less efficient when exposed to sulfur. The Tier 2 rulemaking required 

refiners to take steps to reduce sulfur levels in gasoline by approximately 90 percent, to 

an average of 30 ppm. As discussed in Section IV.A.6, subsequent research provides a 

compelling case that even this level of sulfur not only degrades the emission performance 

of vehicles on the road today, but also inhibits necessary further reductions in vehicle 

emissions performance to reach the Tier 3 standards. Thus, the 10 ppm average sulfur 

standard for Tier 3 is significant in two ways: it enables vehicles designed to the Tier 3 

tailpipe exhaust standards to meet these standards in-use for the duration of their useful 

life, and it facilitates immediate emission reductions from all the vehicles on the road at 

the time the fuel sulfur controls are implemented. EPA is not the first regulatory agency

to recognize the need for lower-sulfur gasoline. Agencies in Europe and Japan have 

already imposed gasoline sulfur caps of 10 ppm, and the State of California is already 

averaging 10 ppm sulfur with a per gallon cap of 20 ppm. Other states are preempted by 

the Clean Air Act from adopting new fuel programs to meet air quality objectives. 

Consequently, they could not receive the air quality benefits of lower sulfur gasoline 

without federal action. 

This action is one aspect of a comprehensive national program regulating 

emissions from motor vehicles. EPA’s final rule for reducing greenhouse gas (GHG) 

emissions from light-duty (LD) vehicles starting with model year (MY) 2017 (referred to 

here as the “2017 LD GHG” standards) is another aspect of this comprehensive program.8 

The Tier 3 program addresses interactions with the 2017 LD GHG rule in a manner that 

aligns implementation of the two actions, to achieve significant criteria pollutant and 

GHG emissions reductions while providing regulatory certainty and compliance 

efficiency. As vehicle manufacturers introduce new vehicle platforms for compliance 

with the GHG standards, they will be able to design them for compliance with the Tier 3 

standards at the same time. The Tier 3 standards are also closely coordinated with 

California’s Low Emission Vehicle (LEV) III program to create a vehicle emissions 

program that will allow automakers to sell the same vehicles in all 50 states. (In 

December 2012 EPA approved a waiver of Clean Air Act preemption for the California 

Air Resources Board’s (CARB’s) LEV III program with compliance beginning in 2015. 

Twelve states adopted the LEV III program under Section 177 of the Clean Air Act.9) 

We have worked closely with individual vehicle manufacturers and their trade 

associations, who have emphasized the importance of a harmonized national program. 

Together, the Tier 3, 2017 LD GHG, and LEV III standards will provide significant 

 

8 EPA’s GHG standards are part of a joint National Program with the National Highway Traffic Safety 

Administration, which also set coordinated standards for Corporate Average Fuel Economy (CAFE). 77

FR 62623 (October 15, 2012).

9 These states include Connecticut, Delaware, Maryland, Maine, Massachusetts, New Jersey, New York, 

Oregon, Pennsylvania, Rhode Island, Washington, and Vermont.
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reductions in GHGs, criteria pollutants and air toxics from motor vehicles while 

streamlining programs and enabling manufacturers to design a single vehicle for 

nationwide sales, thus reducing their costs of compliance. In this way, the Tier 3 

program responds to the May 21, 2010 Presidential Memorandum that requested that 

EPA develop a comprehensive approach toward regulating motor vehicles, including 

consideration of non-GHG emissions standards.10

As part of the systems approach to this program, we have considered the types of 

fuels on which vehicles will be operating in the future. In particular, the renewable fuels 

mandate that was revised by the Energy Independence and Security Act (EISA) and is 

being implemented through the Renewable Fuel Standards program (RFS2)11 is resulting

in the use of significant amounts of ethanol-blended gasoline. We are updating the 

specifications of the emissions test fuel with which vehicles demonstrate compliance with 

emissions standards, in order to better reflect the ethanol content and other properties of 

gasoline that is in use today and is expected in future years.

Section I provides an overview of the vehicle and fuel standards we are finalizing

as well as the impacts of the standards. The public health issues and statutory

requirements that have prompted this action are described in Section II, and our 

discussion of how the Tier 3 standards will reduce emissions and air pollution is 

presented in Section III. Details of the standards and how they will be implemented can 

be found in Sections IV through VI. Sections VII through X contain our discussion of 

the standards’ technological feasibility and costs, benefits, and economic impacts. 

Sections XI through XIII address public participation, statutory and executive orders, and 

statutory provisions and legal authority under the Clean Air Act covered in this 

rulemaking. 

This final rule is based on extensive public input received in response to EPA’s 

Tier 3 proposal. The proposal was signed and posted on the EPA website on March 29, 

2013, and published in the Federal Register on May 21, 2013. EPA held two public 

hearings in Philadelphia and Chicago in April 2013. In response to stakeholder requests, 

EPA extended the public comment period to July 1, 2013. We received more than 

200,000 public comments. A broad range of stakeholders provided comments, including 

state and local governments, auto manufacturers, emissions control suppliers, refiners, 

fuel distributors and others in the petroleum industry, renewable fuels providers, 

environmental organizations, consumer groups, labor groups, private citizens, and others. 

Some of the issues raised in comments included lead time and the program’s start date, 

the vehicle manufacturers’ support for a 50-state program harmonized with California, 

the need for and degree of gasoline sulfur control (including the level of the sulfur cap), 

 

10 The Presidential Memorandum is found at: http://www.whitehouse.gov/the-press-office/presidentialmemorandum-regarding-fuel-efficiency-standards.

11 75 FR 14670 (March 26, 2010).
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the ethanol content of vehicle certification test fuel, and various details on the flexibilities 

and other program design features of both the vehicle and fuels standards.

B. Overview of the Tier 3 Program

In the 14 years since EPA established the Tier 2 Vehicle Program, manufacturers 

of light-duty vehicles and automotive technology suppliers have continued to develop a 

wide range of improved technologies capable of reducing vehicle emissions. The 

California LEV II program has been instrumental in the continuous technology

improvements by requiring year after year reductions in fleet average hydrocarbon levels, 

in addition to requiring the introduction of advanced exhaust and evaporative emission 

controls in partial zero emission vehicles (PZEVs). This technological progress has made 

it possible for manufacturers to achieve emission reductions well beyond the 

requirements of the Tier 2 program if gasoline sulfur levels are lowered further. 

As a result, in conjunction with lower gasoline sulfur standards, we are 

establishing new Tier 3 standards for exhaust emissions of NMOG, NOX, and PM, as 

well as for evaporative hydrocarbon emissions. These vehicle emissions standards will

phase in beginning with MY 2017. The structure of the Tier 3 standards is very similar to 

that of the existing Tier 2 program. As with the Tier 2 program, the standards will apply

to all light-duty vehicles (LDVs, or passenger cars), light-duty trucks (LDT1s, LDT2s, 

LDT3s, and LDT4s) and Medium-Duty Passenger Vehicles (MDPVs). We also are 

establishing separate but closely related standards for heavy-duty vehicles up to 14,000 

lbs Gross Vehicle Weight Rating (GVWR).12 We have concluded that the vehicle 

emissions standards, in conjunction with the reductions in fuel sulfur also required by this 

action, are feasible across the fleet in the timeframe provided. 

Auto manufacturers have stressed the importance of being able to design,

produce, and sell a single fleet of vehicles in all 50 states that complies with both the Tier 

3 and California LEV III programs, as well as the greenhouse gas (GHG)/Corporate 

Average Fuel Economy (CAFE) programs in the same timeframe. To that end, we 

worked closely with the California Air Resources Board and vehicle manufacturers to 

align the two programs as closely as possible. This consistency among the federal and 

California programs means that manufacturers do not need to design unique versions of 

vehicles with different emission control hardware and calibrations for different 

geographic areas. This allows manufacturers to avoid the additional costs of parallel 

design, development, calibration, and manufacturing. We also have designed the Tier 3 

program to be implemented in the same timeframe as the GHG emissions and fuel 

economy standards for model years 2017-2025. We expect that in response to these 

programs, manufacturers will be developing entirely new powertrains for most of their 

 

12 These heavy-duty vehicles were not included in the Tier 2 program but were subject to standards in a 

subsequent rule covering the heavy-duty sector (66 FR 5002, January 18, 2001). 
Page 16 of 529

vehicles. Because the Tier 3 standards will phase in over the same timeframe, 

manufacturers are in a better position to simultaneously respond to all of these 

requirements.

Overall, the final Tier 3 program is very similar to the program we proposed. As 

discussed below and throughout this preamble, the program phases in over several years 

– with the primary vehicle emission standards starting in Model Year (MY) 2017 (2018 

for heavier vehicles) and the gasoline sulfur control provisions beginning in 2017. 

As discussed above, we received a large number and wide range of comments on 

the proposed rule. Several comments raise particularly significant issues concerning 

some fundamental components of the Tier 3 program, including when the vehicle-related 

and fuel-related requirements begin. We briefly discuss these key issues in this section, 

and in more detail later in this preamble. The Summary and Analysis of Comments 

document provides our responses to the comments we received; it is located in the docket 

for this rulemaking and also on EPA’s website at www.epa.gov/otaq/tier3.htm.

1. Major Public Comments and Key Changes from the Proposal

a. Start Date and Lead Time Issues

(1) Gasoline Sulfur Control Program

Many stakeholders commented on the proposed 2017 start date of the Tier 3 

program, with state and NGO organizations supporting finalizing the standards as 

proposed. Conversely, refiners, importers, and others in the fuel industry commented that 

they believed the proposed start date would not provide a sufficient amount of lead time 

to meet the requirements of the Tier 3 program, and that EPA has historically provided at 

least four years of lead time in previous fuels rulemakings. These commenters noted that 

five years of lead time is needed to allow for necessary refinery changes to be made 

during a refinery’s normal turnaround/shutdown schedule (these occur every four years, 

on average) and to allow adequate time for the permitting process. These commenters 

also stated that, given the proposed flexibility provisions for vehicles, that a 2017 fuel 

program start date was not truly needed to enable the vehicle technology. Further, these 

commenters stated that they believed insufficient lead time would drive up the costs for 

regulated entities as they would need to do unscheduled shutdowns to install and/or 

revamp equipment to meet the proposed standards. Lastly, they stated that the 

uncertainty regarding the potential availability of credits would make meeting a 2017 

start date more challenging.

As discussed in greater detail in Section V below, we are finalizing the proposed 

start date of January 1, 2017. We understand refiners’ concerns, including their concerns 

over the necessary capital investments and potential off-cycle turnarounds/shutdowns to 

make refinery modifications for Tier 3. Especially in light of the additional flexibilities 

we are finalizing beyond those already in the proposal, we are confident that the program 
Page 17 of 529

being finalized today addresses these concerns. The magnitude of the investments 

necessary to comply with Tier 3 is much smaller than what was required for Tier 2 or 

ultra-low sulfur diesel. Considering all the flexibilities offered to regulated parties, there 

is, in effect, nearly 6 years of lead time provided for those refineries that may need it. As 

discussed in Section V.D, we are finalizing a credit averaging, banking, and trading 

(ABT) program that will allow for a smooth transition from the Tier 2 to Tier 3 ABT 

programs (including provisions for early credit generation beginning in 2014). These 

early credit provisions, coupled with the ability to carry over credits from Tier 2 into Tier 

3 (an additional flexibility being finalized today that was not part of the proposal), will 

allow for early actions to reduce sulfur levels by some refineries to be used to delay the 

need for actions at other refineries until 2020. This structure of the ABT program allows 

refiners and importers the flexibility to choose the most economical compliance strategy

– investment in technology, use of credits, or both – for meeting the Tier 3 average 

gasoline sulfur standard. In addition, approved small refiners and small volume refineries 

are given an additional three years from the January 1, 2017, Tier 3 program start date to 

comply (January 1, 2020).

We proposed that the Tier 2 ABT program would not only be separate from the 

Tier 3 ABT program, but that it would also end at the start of the Tier 3 program in 2017. 

The implications of this meant that any Tier 2 credits generated after 2012 would run the 

risk of expiring before the end of their full five-year life if they were not used before 

January 1, 2017. Commenters requested that EPA consider allowing such Tier 2 

“banked” credits to receive their full five-year life. This would eliminate any incentive 

refiners may have to use these credits prior to the end of the Tier 2 program to raise their 

in-use sulfur levels. The ABT program that we are finalizing today enables a seamless 

transition from Tier 2 to Tier 3, including an allowance for Tier 2 banked credits to be 

used for their full five-year life or through December 31, 2019, whichever is earlier. Not 

only does this provision effectively provide more lead time and flexibility for refiners and 

importers, but we believe these banked credits will help to provide certainty of the 

availability of credits for refiners and importers who may want to rely on them for 

compliance.

Finally, as discussed in Section V.E.2, we are also finalizing hardship provisions 

that allow refiners to petition for delayed compliance, on a case-by-case basis, for 

situations of extreme hardship or extreme unforeseen circumstances. These provisions, 

similar to those implemented in past fuel rulemakings, provide a safety valve should all 

the other flexibilities provided prove insufficient. As part of these hardship provisions, 

we are finalizing the ability for refiners to carry a deficit for up to 3 years, providing them 

with yet additional flexibility during the transition to Tier 3 should it prove necessary.

(2) Vehicle Emission Control Program

There were no major concerns raised for the proposed MY 2017 start date for 

lighter light-duty vehicles, although commenters from the auto manufacturing industry 

raised concerns about the lead time we proposed for heavier light-duty vehicles. 
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Specifically, commenters pointed to Clean Air Act section 202(a)(3)(C) that, for vehicles 

over 6,000 lbs GVWR, requires that EPA emission standards provide at least four years

of lead time and three years of regulatory stability. 

In light of this statutory requirement, in addition to the primary declining fleet 

average standards starting in MY 2018 for heavier vehicles, EPA proposed an alternative 

phase-in schedule for any manufacturer that prefers a longer lead time and annual 

stability for these vehicles in lieu of the declining fleet average standards option. The 

commenters stated that the proposed alternative pathway would be too difficult to take 

advantage of in comparison to the primary program and thereby failed to comply with the 

Clean Air Act. 

In considering these comments, EPA also considered that during the development 

of the Tier 3 program and in their comments, the same auto industry commenters 

consistently urged EPA to design the Tier 3 program to harmonize with the California 

LEV III standards as closely and as early as possible. As discussed in detail below in 

Section IV.A, extensive data that EPA has generated or received continue to support the 

conclusion that the primary fleet-average standards provide a compliance path that is 

feasible across the industry and that closely harmonizes with LEV III. EPA believes that 

we have reasonably resolved these somewhat competing concerns -- early harmonization 

vs. additional lead time -- by finalizing the primary declining fleet average standards as 

proposed while also finalizing revised alternative phase-in compliance schedules (see 

Section IV.A.2.c). In response to the comments on this topic, we have revised the 

alternative phase-in schedules to reduce their associated burden for manufacturers, while 

still maintaining environmental benefits that are equivalent to the primary program. We 

also include provisions in the percent-of-sales phase-in alternatives that allow 

manufacturers to exclude vehicle models that begin their 2019 model year production 

early in 2018, in order to provide four years of lead time. 

b. Emissions Test Fuel

In-use gasoline has changed considerably since EPA last revised specifications for 

the test gasoline used in emissions testing of light- and heavy-duty vehicles. Perhaps 

most importantly, gasoline containing 10 percent ethanol by volume (E10) has replaced 

non-oxygenated gasoline (E0) across the country. As a result, we are updating federal 

emissions test fuel specifications to better match in-use fuel. 

In the NPRM, EPA proposed that the specified gasoline for emissions testing be 

changed from E0 to E15 as a forward-looking approach. Since then, several factors have 

led EPA to reconsider that approach, including minimal proliferation on a national scale 

of stations offering E15 and the complexities that E15 would introduce for long-term 

harmonization with California’s use of E10 in their LEVIII program. We received 

comments from a broad set of stakeholders including the auto and oil industries, states, 

and NGOs with a general consensus that E15 would not be appropriate as the official test 

fuel at this time. Ethanol industry commenters supported E15 certification fuel, but 
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provided no timeline by which this blend level would be representative of in-use fuel. In 

light of the comments received and EPA’s assessment of the current and projected levels

of ethanol in gasoline in use, we are finalizing E10 as the new emissions test fuel.

In deciding to finalize E10 test fuel, EPA considered whether to change the 

volatility of the test fuel, typically expressed as pounds per square inch (psi) Reid Vapor 

Pressure (RVP). As discussed in detail in Section IV.F, after considering technical and 

policy implications as well as stakeholder comments, we have concluded that the most 

appropriate approach is to maintain an RVP of 9 psi for the E10 emissions test fuel at this 

time. EPA considered raising test fuel RVP to 10 psi, but decided to leave it unchanged 

at 9 psi based on what would have been the associated increase in stringency of the Tier 3 

evaporative standard with 10 psi and the loss of regulatory harmony on evaporative 

emissions with California’s LEV III program. 

As a result, after reassessing market trends and considering comments, EPA 

concludes that the most appropriate approach is to finalize an ethanol content of 10 

percent and an RVP of 9 psi for emissions test gasoline. We will continue to monitor 

ethanol trends in the gasoline market, as discussed later in this preamble. 

c. Gasoline Sulfur Caps

As described in more detail in Section V.C. we proposed two options for the Tier 

3 per-gallon sulfur caps—maintaining the Tier 2 refinery gate sulfur cap of 80 ppm (with 

a 95 ppm downstream sulfur cap), and lowering to a 50 ppm refinery gate sulfur cap 

beginning January 1, 2020 (with a 65 ppm downstream cap). We received comments 

supporting lower per-gallon caps which noted potential environmental benefits, greater 

certainty that vehicles would see lower and more uniform gasoline sulfur levels, and the 

ability to enable new vehicle technologies requiring very low sulfur levels. Conversely, 

comments received in support of maintaining the Tier 2 per-gallon caps cited concerns on 

cost, flexibility for turnarounds/unplanned shutdowns (due to refinery fires, natural 

disasters, etc.), and gasoline supply and/or price impacts.

Analysis performed since the time of the proposal found that a lower refinery gate 

cap would likely result in higher costs to the fuels industry and a decreased ability to 

handle off-spec product (potentially impacting gasoline supply and pricing), without any

significant increase in the nationwide emissions reductions provided by the Tier 3 

program. Thus, in today’s action we are retaining the Tier 2 per-gallon sulfur caps. The 

80 ppm refinery gate cap will provide refiners needed flexibility in allowing for 

naturally-occurring fuel batch variability, as well as more certainty that they will be able 

to continue producing and distributing gasoline during turnarounds/upsets to avoid a total 

shutdown. It will also provide more certainty for transmix processors, additive 

manufacturers, and other downstream parties in producing gasoline.

However, we do understand commenters’ concerns that retaining the Tier 2 sulfur 

caps might create regional differences in the benefits of the Tier 3 program. Therefore 
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we will continue to monitor in-use sulfur levels and their impact on vehicle emissions to 

ascertain whether a future reduction in the per-gallon cap may be necessary.

d. Effect of Gasoline Sulfur on Tier 3 Vehicle Emissions

The need for and level of gasoline sulfur control was a key issue raised in public 

comments. The petroleum industry raised concerns that there was insufficient basis for 

the proposed 10 ppm average sulfur level, while auto manufacturers and emissions 

control equipment manufacturers stressed that the feasibility of the Tier 3 vehicle 

standards was dependent on near-zero gasoline sulfur levels. This issue is discussed in 

detail below in Section IV.A.6. In sum, EPA believes that the range of studies conducted 

by EPA and others in recent years, along with the comments submitted by the auto 

industry and emissions control manufacturers during the comment period and more 

recently, strongly reinforce our conclusion that the impact of gasoline sulfur poisoning on 

exhaust catalyst performance is significant. 

Sulfur is a well-known catalyst poison. The nature of sulfur’s interactions with 

active catalytic materials is complex and varies with catalyst composition, exhaust gas 

composition, and exhaust temperature. Thus, even if a manufacturer were able to certify 

a new vehicle to the new stringent standards, the manufacturer’s ability to maintain the 

emission performance of that vehicle in-use is greatly jeopardized if the vehicle is being 

operated on gasoline sulfur levels greater than 10 ppm. In fact, due to the variation in 

actual vehicle operation, any amount of gasoline sulfur will deteriorate catalyst 

efficiency. Vehicle manufacturers and suppliers, both individually and through their 

trade associations, stressed the need for gasoline sulfur to be reduced to near zero levels 

in order for them to meet the proposed standards. However, we believe that a 10 ppm 

average sulfur level is sufficiently low to enable compliance with the Tier 3 vehicle 

standards, and as described below and in Section V, reducing sulfur levels further would 

cause sulfur control costs to quickly escalate. 

Taken together, this information provides a compelling argument that the

fleetwide Tier 3 vehicle standards are achievable only with a reduction of gasoline sulfur 

content from the current 30 ppm average down to a 10 ppm average. 

e. SFTP (US06) PM Standard for Light-Duty Vehicles

The final Tier 3 vehicle standards are largely unchanged from their proposed 

levels. One change from the proposal is the PM emissions standards as measured on the 

US06 test cycle. The US06 cycle is part of the composite Supplemental Federal Test 

Procedure (SFTP) and simulates aggressive driving. The US06 PM standards are part of 

the suite of Tier 3 tailpipe standards that limit emissions under a wide range of common 

vehicle driving conditions. Newer emissions test data presented in the NPRM, as well as 

more recent additional test data submitted in public comments, show that a numerically 

lower US06 PM standard is feasible and appropriately reflects the actual emissions 
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performance achieved by many vehicles in the fleet today while preventing increased 

emissions in the future. 

Taken together, the test results clearly show that most current light-duty vehicles 

– regardless of engine technology, emission control strategy, or vehicle size – are 

performing at much lower US06 emission levels than previously documented. Based on 

these newer data, we believe that it is appropriate to finalize a numerically lower US06 

PM emission standard for LDVs, LDTs, and MDPVs, and to set a single standard for 

both lighter and heavier vehicles in this vehicle segment. In general, the final US06 PM 

standard for these vehicles begins to phase in at a level of 10 mg/mi in MYs 2017 and 

2018, stepping down to a level of 6 mg/mi in MY2019. See Section IV.A.4.b for 

additional discussion of the US06 standards and how they will phase in. 

2. Key Components of the Tier 3 Program

a. Tailpipe Standards for Light-Duty Vehicle, Light-Duty Truck, and MediumDuty Passenger Vehicle Tailpipe Emissions

We are establishing a comprehensive program that includes new fleet-average 

standards for the sum of NMOG and NOX tailpipe emissions (presented as NMOG+NOX) 

as well as new per-vehicle standards for PM.13 These standards, when applied in 

conjunction with reduced gasoline sulfur content, will result in very significant 

improvements in vehicle emissions from the levels of the Tier 2 program. For these 

pollutants, the standards are measured on test procedures that represent a range of vehicle 

operation, including the Federal Test Procedure (or FTP, simulating typical driving) and 

the Supplemental Federal Test Procedure (or SFTP, a composite test simulating higher 

ambient temperatures, higher vehicle speeds, and quicker accelerations). In addition to 

the standards, we are extending the regulatory useful life period during which the 

standards apply (see Section IV.A.7.b below) and making test fuel more representative of 

expected real-world fuel (see Section I.B.2.e below). The final standards are in most 

cases identical to those of California’s LEVIII program, which provides the 50-state 

harmonization strongly supported by the auto industry. 

As proposed, the new Tier 3 FTP and SFTP NMOG+NOX standards are fleetaverage standards, meaning that a manufacturer calculates the average emissions of the 

vehicles it sells in each model year and compares that average to the applicable standard 

for that model year. The manufacturer certifies each of its vehicles to a per-vehicle “bin” 

standard (see Section IV.A.2) and sales-weights these values to calculate its fleet-average 

NMOG+NOX emissions for each model year. Table I-1 summarizes the fleet average 

standards for NMOG+NOX evaluated over the FTP. The standards for light-duty

vehicles begin in MY 2017 at a level representing a 46 percent reduction from the Tier 2 

 

13A discussion of the reasons for combining NMOG and NOX for this purpose is in Section IV.A.3.a below.
Page 22 of 529

requirements. For the light-duty fleet over 6000 lbs GVWR, and MDPVs, the standards 

apply beginning in MY 2018. As shown, these fleet-average standards decline during the 

first several years of the program, becoming increasingly stringent until ultimately

reaching an 81 percent reduction when the transition is complete. The FTP NMOG+NOX

program includes two separate sets of declining fleet-average standards, with LDVs and 

small light trucks in one grouping and heavier light trucks and MDPVs in a second 

grouping, that converge at 30 milligrams per mile (mg/mi) in MY 2025 and later. As 

mentioned above, we are also providing alternative percent phase-in schedules for this 

and the other light-duty standards. 

Table I-1 Tier 3 LDV, LDT, and MDPV Fleet Average FTP NMOG+NOX

Standards (mg/mi) 

Model Year

2017a2018 2019 2020 2021 2022 2023 2024 2025 

and later

LDV/LDT1b86 79 72 65 58 51 44 37 30

LDT2,3,4 and 

MDPV

101 92 83 74 65 56 47 38 30

a For LDV and LDTs above 6000 lbs GVWR and MDPVs, the fleet average standards apply beginning in 

MY 2018.

b These standards apply for a 150,000 mile useful life. Manufacturers can choose to certify some or all of 

their LDVs and LDT1s to a useful life of 120,000 miles. If a vehicle model is certified to the shorter useful 

life, a proportionally lower numerical fleet-average standard applies, calculated by multiplying the 

respective 150,000 mile standard by 0.85 and rounding to the nearest mg. See Section IV.A.7.c. 

Similarly, as proposed, the NMOG+NOX standards measured over the SFTP are

fleet-average standards, declining from MY 2017 until MY 2025, as shown in Table I-2. 

In this case, the same standards apply to both lighter and heavier vehicles in the lightduty fleet. In MY 2025, the SFTP NMOG+NOX standard reaches its final fleet average 

level of 50 mg/mi.

Table I-2 Tier 3 LDV, LDT, and MDPV Fleet Average SFTP NMOG+NOX

Standards (mg/mi)

Model Year

2017a2018 2019 2020 2021 2022 2023 2024 2025 

and later

NMOG + NOX 103 97 90 83 77 70 63 57 50

a For LDVs and LDTs above 6000 lbs GVWR and MDPVs, the fleet average standards apply beginning in 

MY 2018. 

As proposed, manufacturers can also earn credits if their fleet average 

NMOG+NOX performance is better than the applicable standard in any model year. 
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Credits that have been previously banked or obtained from other manufacturers can be 

used, or credits can be traded to other manufacturers. Manufacturers would also be 

allowed to carry forward deficits in their credit balance. (See Sections IV.A.7.a and 

IV.A.7.m).

We are also establishing PM standards as part of the Tier 3 program, for both the 

FTP and US06 cycles (as described above, US06 is a component of the SFTP test). 

Research has demonstrated that the level of PM from gasoline light-duty vehicles is more 

significant than previously thought.14 Although many vehicles today are performing at or 

near the levels of the new standards, the data indicate that improvements, especially in 

high-load fuel control and in the durability of engine components, are possible. 

Under typical driving, as simulated by the FTP, the PM emissions of most 

current-technology gasoline vehicles are fairly low at certification and in use, well below 

the Tier 2 PM standards. At the same time we see considerable variation in PM 

emissions among vehicles of various makes, models, and designs. As a result, as 

proposed, we are setting the new FTP PM standard at a level that will ensure that all new 

vehicles perform at the level already being achieved by well-designed Tier 2 vehicles. 

The PM standards apply to each vehicle separately (i.e., not as a fleet average). Also, in 

contrast to the declining NMOG+NOX standards, the PM standard on the FTP for 

certification testing is 3 mg/mi for all vehicles and for all model years. As for the 

NMOG+NOX standards, for vehicles over 6000 lbs GVWR, the FTP PM standard applies

beginning in MY 2018. Manufacturers can phase in their vehicle models as a percent of 

U.S. sales through MY 2022. Most vehicles are already performing at this stringent PM 

level, and the primary intent of the standard is to bring all light-duty vehicles to the 

typical level of PM performance being demonstrated by many of today’s vehicles. 

As proposed, the Tier 3 program also includes a temporary in-use FTP PM 

standard of 6 mg/mi for the testing of in-use vehicles that applies during the percent 

phase-in period only. This in-use standard will address the in-use variability and 

durability uncertainties that accompany the introduction of new technologies. Table I-3

presents the FTP certification and in-use PM standards and the phase-in percentages. 

Table I-3 Phase-In for Tier 3 FTP PM Standards 

2017a2018 2019 2020 2021 2022 and 

later

Phase-In

(percent of U.S. sales)

20b20 40 70 100 100

 

14 Nam, E.; Fulper, C.; Warila, J.; Somers, J.; Michaels, H.; Baldauf, R.; Rykowski, R.; and Scarbro, C. 

(2008). Analysis of Particulate Matter Emissions from Light-Duty Gasoline Vehicles in Kansas City, 

EPA420-R-08-010. Assessment and Standards Division Office of Transportation and Air Quality U.S. 

Environmental Protection Agency Ann Arbor, MI, April 2008.
Page 24 of 529

Certification 

Standard (mg/mi)

3 3 3 3 3 3

In-Use Standard 

(mg/mi)

6 6 6 6 6 3

a

For LDVs and LDTs above 6000 lbs GVWR and MDPVs, the FTP PM standards apply beginning in MY 

2018.

b Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, or 

alternatively with 10 percent of their total LDV, LDT, and MDPV fleet. 

Finally, as discussed in Section I.B.1.e above, the Tier 3 program includes PM 

standards evaluated over the US06 driving cycle (the US06 is one part of the SFTP 

procedure) of 10 mg/mi through MY 2018 and of 6 mg/mi for 2019 and later model 

years, for light-duty vehicles. As in the case of the FTP PM standards, the intent of the 

US06 PM standard is to bring the emission performance of all vehicles to that already 

being demonstrated by many vehicles in the current light-duty fleet. 

b. Heavy-Duty Vehicle Tailpipe Emissions Standards

As discussed in detail in Section IV.B, we are setting Tier 3 exhaust emissions 

standards for complete heavy-duty vehicles (HDVs) between 8,501 and 14,000 lbs

GVWR. Vehicles in this GVWR range are often referred to as Class 2b (8,501-10,000 

lbs) and Class 3 (10,001-14,000 lbs) vehicles, and are typically heavy-duty pickup trucks 

and work or shuttle vans. Most are built by companies with even larger light-duty truck 

markets, and as such they frequently share major design characteristics and emissions 

control technologies with their LDT counterparts. However, in contrast to the largely 

gasoline-fueled LDT fleet, roughly half of the heavy-duty pickup and van fleet in the 

U.S. is diesel-fueled. This is an important consideration in setting emissions standards, 

as diesel engine emissions control strategies differ from those of gasoline engines.

As proposed, the key elements of the Tier 3 program for HDVs parallel those 

being adopted for passenger cars and LDTs, with adjustments in standard levels, emission 

test requirements, and implementation schedules appropriate to this sector. These key

elements include combined NMOG+NOX declining fleet average standards, a phase-in of 

PM standards, adoption of a new emissions test fuel for gasoline-fueled vehicles, 

extension of the regulatory useful life to 150,000 miles or 15 years (whichever occurs 

first), and a first-ever requirement for HDVs to meet standards over an SFTP drive cycle 

that addresses real-world driving modes not well-represented by the FTP cycles.

We are adopting the Class 2b and Class 3 fleet average NMOG+NOX standards 

shown in Table I-4, as proposed. The standards become more stringent in successive 

model years from 2018 to 2022, with voluntary standards made available in 2016 and 

2017, all of which are set at levels that match those of California’s LEV III program for 

these classes of vehicles. Each covered HDV sold by a manufacturer in each model year 

contributes to this fleet average based on the mg/mi NMOG+NOX standard level of the 

“bin” declared for it by the manufacturer, who chooses from a set of seven discrete Tier 3 
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bins specified in the regulations. These bin standards then become the compliance 

standards for the vehicle over its useful life, with some adjustment provided for in-use 

testing in the early model years of the program.

As proposed, manufacturers can also earn credits for fleet average NMOG+NOX

levels below the standard in any model year. Tier 3 credits that were previously banked, 

obtained from other manufacturers, or transferred across the Class 2b/Class 3 categories 

can be used to help demonstrate compliance. Unused credits expire after 5 model years. 

Manufacturers will also be allowed to carry forward deficits in their credit balance for up 

to 3 model years.

Table I-4 Tier 3 HDV Fleet Average FTP NMOG+NOX Standards (mg/mi)

Voluntary Required Program

Model 

Year 2016 2017 2018 2019 2020 2021 2022 and later

Class 2b 333 310 278 253 228 203 178

Class 3 548 508 451 400 349 298 247

 

We are adopting the proposed FTP PM standards of 8 mg/mi and 10 mg/mi for 

Class 2b and Class 3 HDVs, respectively, phasing in as an increasing percentage of a 

manufacturer’s sales per year. We are adopting the same phase-in schedule as for the 

light-duty sector during model years 2018-2019-2020-2021: 20-40-70-100 percent, 

respectively, and a more flexible but equivalent alternative PM phase-in is also being 

adopted. Tier 3 HDVs will also be subject to CO and formaldehyde exhaust emissions 

standards that are more stringent than the existing standards.

Finally, we are setting first-ever nationwide SFTP standards for HDVs to ensure a 

robust overall control program that precludes high off-FTP cycle emissions by having 

vehicle designers consider them in their choice of compliance strategies. As for lightduty vehicles, we are requiring that SFTP compliance be based on a weighted composite 

of measured emissions from testing over the FTP cycle, the SC03 cycle, and an 

aggressive driving cycle, with the latter tailored to various HDV sub-categories: the 

US06 cycle for most HDVs, the highway portion of the US06 cycle for low power-toweight Class 2b HDVs, and the LA-92 (or “Unified”) cycle for Class 3 HDVs. The 

SFTP standards are the same as those adopted for California LEV III vehicles, and apply 

to NMOG+NOX, PM, and CO emissions.

The HDV program outlined above and described in detail in Section IV.B is 

substantially what we proposed. Commenters generally supported the scope, stringency, 
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and implementation phase-in of this program. However, some industry commenters 

requested changes to some specific provisions of the proposal, and the program we are 

adopting reflects improvements we have made in response. These are: (1) a limited 

allowance for engine certification of Class 3 complete diesel vehicles to avoid a potential 

need for dual chassis- and engine-based certification and to better harmonize with LEV 

III, (2) relaxed interim in-use testing standards to facilitate a smooth transition to the Tier 

3 standards and to better harmonize with LEV III, (3) adoption of combined 

NMOG+NOx standards for the two highest (interim) bins, with a restriction placed on 

NOx levels in certification testing, to enhance the utility of these bins and to better 

harmonize with LEV III, and (4) a provision in the percent-of-sales phase-in alternative 

to allow manufacturers to exclude vehicle models that begin their 2019 model year 

production early in 2018, in order to provide four years of lead time. Commenters also 

requested relaxed standards for testing at high altitudes and changes to the credits 

program structure for generation of early credits and use of LEV III-based “vehicle 

emission credits”, but we did not adopt these for reasons explained in Section IV.B.

Overall, we expect the Tier 3 program we are adopting for HDVs to result in 

substantial reductions in harmful emissions from this large fleet of work trucks and vans. 

The fully-phased in Tier 3 standards levels for NMOG+NOX and PM are on the order of 

60 percent lower than the current standards that took full effect in the 2009 model year.

c. Evaporative Emission Standards

Gasoline vapor emissions from vehicle fuel systems occur when a vehicle is in 

operation, when it is parked, and when it is being refueled. These evaporative emissions, 

which occur on a daily basis from gasoline-powered vehicles, are primarily functions of 

temperature, fuel vapor pressure, and activity. EPA first instituted evaporative emission 

standards in the early 1970s to address emissions when vehicles are parked after being 

driven. These are commonly referred to as hot soak plus diurnal emissions. Over the 

subsequent years the test procedures have been modified and improved and the standards 

have become more numerically stringent. We have addressed emissions which arose 

from new fuel system designs by putting in place new requirements such as running loss 

emission standards and test procedure provisions to address permeation emissions. 

Subsequently standards were put in place to control refueling emissions from all classes 

of gasoline-powered motor vehicles up to 10,000 lbs GVWR. Evaporative and refueling 

emission control systems have been in place for most of these vehicles for many years. 

These controls have led to significant reductions, but evaporative and refueling emissions 

still constitute 30-40 percent of the summer on-highway mobile source hydrocarbon 

inventory. These fuel vapor emissions are ozone and PM precursors, and also contain air 

toxics such as benzene. 

To control evaporative emissions, EPA is establishing more stringent standards 

that will require covered vehicles to have essentially zero fuel vapor emissions in use. 

These include more stringent evaporative emissions standards, new test procedures, and a 

new fuel/evaporative system leak emission standard. The program also includes 
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refueling emission standards for all complete heavy-duty gasoline vehicles (HDGVs) 

over 10,000 lbs GVWR. EPA is including phase-in flexibilities as well as credit and 

allowance programs. The standards, harmonized with California’s “zero evap” standards, 

are designed to allow for a use of common technology in vehicle models sold throughout 

the U.S. The level of the standard remains above zero to account for nonfuel background 

emissions from the vehicle hardware.

Requirements to meet the Tier 3 evaporative emission regulations phase in over a 

six model year period. We are finalizing three options for the 2017 model year, but after 

that the sales percentage requirements are 60 percent for MYs 2018 and 2019, 80 percent 

for model years 2020 and 2021, and 100 percent for model years 2022 and later. In Table 

I-5 we present the Tier 3 evaporative hot soak plus diurnal emission standards by vehicle 

class. The standards are approximately a 50 percent reduction from the existing 

standards. To enhance flexibility and reduce costs, EPA is finalizing provisions that 

allow manufacturers to generate allowances through early certifications (basically before 

the 2017 model year) and to demonstrate compliance using averaging concepts. 

Manufacturers may comply on average within each of the four vehicle categories, but not 

across these categories. EPA is not making any changes to the existing light-duty

running loss or refueling emission standards, with the exception of the certification test 

fuel requirement discussed in Section I.B.2 below.

Table I-5 Tier 3 Evaporative Emission Standards (g/test)

Vehicle Class Highest Hot Soak + Diurnal Level

(over both 2-day and 3-day diurnal tests)

LDV, LDT1 0.300

LDT2 0.400

LDT3, LDT4, MDPV 0.500

HDGVs 0.600

Flexible Fuel Vehicles (FFVs) must meet the same evaporative emission 

standards as non-FFVs using Tier 3 emissions certification test fuel. However, FFVs 

must meet the refueling emission standards using 10 psi RVP fuel to account for 

emissions resulting from commingling with non-E85 blends that may be in the vehicle’s 

fuel tank.

EPA is establishing the canister bleed emission test procedure and emission 

standard to help ensure fuel vapor emissions are eliminated. Under this provision, 

manufacturers are required to measure diurnal emissions over the 2-day diurnal test 

procedure from just the fuel tank and the evaporative emission canister and comply with 

a 0.020 gram per test (g/test) standard for all LDVs, LDTs, and MDPVs, without 

averaging. The corresponding canister bleed test standard for HDGVs is 0.030 g/test. 

The Tier 3 evaporative emission standards will be phased in over a period of six model 

years between MY 2017 and MY 2022, with the leak test phasing in beginning in 2018.
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Data from in-use evaporative emissions testing indicates that vapor leaks from 

vehicle fuel/evaporative systems are found in the fleet and that even very small leaks 

have the potential to make significant contributions to the mobile source VOC inventory. 

To help address this issue, we are also adding a new standard and test procedure to 

control vapor leaks from vehicle fuel and vapor control systems. The standard will

prohibit leaks with a cumulative equivalent diameter of 0.02 inches or greater. We are 

adding this simple and inexpensive test and emission standard to help ensure vehicles 

maintain zero fuel vapor emissions over their full useful life. New LDV, LDT, MDPV, 

and HDGV equal to or less than 14.000 lbs GVWR meeting the Tier 3 evaporative 

emission regulations are also required to meet the leak standard beginning in the 2018 

model year. Manufacturers must comply with the leak standard phase-in on the same 

percentage of sales schedule as that for the Tier 3 evaporative emission standards. 

Manufacturers will comply with the leak emission standard during certification and in 

use. The leak emission standard does not apply to HDGVs above 14,000 lbs GVWR.

EPA is also establishing new refueling emission control requirements for all 

complete HDGVs equal to or less than 14,000 lbs GVWR (i.e., Class 2b/3 HDGVs), 

starting in the 2018 model year, and for all larger complete HDGVs by the 2022 model 

year. The existing refueling emission control requirements apply to complete Class 2b 

HDGVs, and EPA is extending those requirements to other complete HDGVs, since the 

fuel and evaporative control systems on these vehicles are very similar to those on their 

lighter-weight Class 2b counterparts.

 

d. Onboard Diagnostic Systems (OBD)

EPA and CARB both have OBD regulations applicable to the vehicle classes 

covered by the Tier 3 emission standards. In the past the requirements have been very

similar, so most manufacturers have met CARB OBD requirements and, as permitted in 

our regulations, EPA has generally accepted compliance with CARB’s OBD 

requirements as satisfying EPA’s OBD requirements. Over the past several years CARB 

has upgraded its requirements to help improve the effectiveness of OBD in ensuring good 

in-use exhaust and evaporative system emissions performance. We have reviewed these 

provisions and agree with CARB that these revisions will help to improve in-use 

emissions performance, while at the same time harmonizing with the CARB program. 

Toward that end, we are adopting and incorporating by reference the current CARB OBD 

regulations, effective for the 2017 MY, with a few minor differences including phase-in 

flexibility provisions and specific additions to enhance the implementation of the leak 

standard. EPA is retaining the provision that certifying with CARB’s program would 

permit manufacturers to seek a separate EPA certificate on that basis. 
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e. Emissions Test Fuel

As described above, after reassessing market trends and considering comments, 

EPA is finalizing E10 as the ethanol blend level in emissions test gasoline for Tier 3 

light-duty and heavy-duty gasoline vehicles. We will continue to monitor the in-use 

gasoline supply and based on such review may initiate rulemaking action to revise the 

specifications for emissions test fuel to include a higher ethanol blend level. EPA is also 

making additional changes that are consistent with CARB’s LEV III emissions test fuel 

specifications, including new specifications for octane, distillation temperatures, 

aromatics, olefins, sulfur and benzene. (See Section IV.F below for a detailed discussion 

of all the revised emission test fuel parameters.) 

As discussed in Sections IV.A.7.d (tailpipe emission testing) and IV.C.5.b 

(evaporative emission testing), we are requiring certification of all Tier 3 light-duty and 

chassis-certified heavy-duty gasoline vehicles on federal E10 test fuel. The new test fuel 

specifications will apply to new vehicle certification, assembly line, and in-use testing. 

With a change in the ethanol content of the test fuel, EPA also needed to consider 

whether a change is warranted in the volatility of the test fuel, typically expressed as 

pounds per square inch (psi) Reid Vapor Pressure (RVP). As discussed in detail in 

Section IV.F below, after considering several technical and policy implications as well as 

stakeholder comments, EPA has concluded that the most appropriate approach is to 

maintain an RVP of 9 psi for the E10 certification fuel at this time. 

In addition to finalizing a new E10 emissions test fuel, we are also finalizing

detailed specifications for the E85 emissions test fuel used for flexible fuel vehicle (FFV) 

certification, as discussed in Section IV.F.3.

15

 This will resolve uncertainty and 

confusion in the certification of FFVs designed to operate on ethanol levels up to 83 

percent. Furthermore, we allow vehicle manufacturers to request approval for an 

alternative certification fuel such as a high-octane 30 percent ethanol by volume blend 

(E30) for vehicles that may be optimized for such fuel. 

f. Fuel Standards

Under the Tier 3 fuel program, gasoline must contain no more than 10 ppm sulfur 

on an annual average basis beginning January 1, 2017. Similar to the Tier 2 gasoline 

program, the Tier 3 program will apply to gasoline in the U.S. and the U.S. territories of 

Puerto Rico and the Virgin Islands, excluding California. The program will result in 

gasoline that contains, on average, two-thirds less sulfur than it does today. In addition, 

following discussions with numerous refiners and other segments of the fuel market (e.g., 

 

15 Flexible fuel vehicles are currently required to meet emissions certification requirements using both E0 

and E85 test fuels. However, there were no detailed regulatory specifications regarding the composition of 

E85 test fuels before those finalized today.
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pipelines, terminals, marketers, ethanol industry representatives, transmix processors, 

additive manufacturers, etc.), the Tier 3 fuel program contains considerable flexibility to 

ease both initial and long-term implementation of the program. The program that we are

finalizing today includes an averaging, banking, and trading (ABT) program that allows

refiners and importers to spread out their investments over nearly a 6 year period through 

the use of an early credit program and then rely on ongoing nationwide averaging to meet 

the 10 ppm sulfur standard. In addition there is a three-year delay for small refiners and 

“small volume refineries”. As a result of the early credit program, we anticipate 

considerable reductions in gasoline sulfur levels prior to 2017, with a complete transition

to the 10 ppm average occurring by January 1, 2020. For more information on the 

gasoline sulfur program flexibilities, refer to Section V.E. 

Under today’s Tier 3 gasoline sulfur program, we are maintaining the current 80 

ppm refinery gate and 95 ppm downstream per-gallon caps. We also evaluated and 

sought comment on the potential of lowering the per-gallon caps. While there are 

advantages and disadvantages with each of the sulfur cap options that we proposed, we 

believe that retaining the current Tier 2 sulfur caps is prudent at this time, as explained in 

more detail in Section V.C. Further, the stringency of the 10 ppm annual average 

standard will result in reduced gasoline sulfur levels nationwide. Today’s program 

requires that manufacturers of gasoline additives that are used downstream of the refinery

at less than 1 volume percent must limit the sulfur contribution to the finished gasoline 

from the use of their additive to less than 3 ppm when the additive is used at the 

maximum recommended treatment rate (see Section V.C.2). This requirement will 

preclude the unnecessary use of high sulfur content additives in gasoline.

The vehicle emissions standards finalized today are fuel-neutral (i.e., they are 

applicable regardless of the type of fuel that the vehicle is designed to use). There 

currently are no sulfur standards for the fuel used in compressed natural gas (CNG) and 

liquid propane gas (LPG) vehicles. We requested comment on whether it is necessary for 

EPA to establish sulfur standards for CNG and LPG to enable them meeting more 

stringent vehicle emissions standards. EPA is deferring finalizing in-use sulfur 

requirements for CNG/LPG in this final rule to provide additional time to work with 

stakeholders to collect data on current CNG/LPG sulfur content, to determine whether 

additional control of in-use CNG/LPG sulfur content is needed, and to evaluate the 

feasibility and costs associated with potential additional sulfur controls (see Section V.J). 

Given that the information provided suggests that CNG/LPG sulfur levels tend to be low 

already, the vehicle emissions standards finalized today will apply to CNG/LPG vehicles 

in addition to vehicles fueled on gasoline, diesel fuel, or any other fuel. The sulfur 

content of highway diesel fuel is already required to meet a 15 ppm sulfur cap, which is 

sufficient for diesel fuel vehicles to meet the Tier 3 emissions standards.

As the number of flex-fuel vehicles (FFVs) in the in-use fleet increases, it is 

becoming increasingly important that all fuels used in FFVs, not just gasoline, meet fuel 

quality standards. A lack of clarity regarding the standards that apply to fuels used in 

FFVs could also act to impede the further expansion of ethanol blended fuels with 
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concentrations greater than 15 volume percent, which is important to satisfying the 

requirements of the RFS2 program. Hence, we sought comment on appropriate 

regulatory mechanisms to implement in-use quality standards for E51-83 and E16-50 in 

the Tier 3 proposal. Additional work is needed on some issues that could not be 

accommodated within the timeline for this Tier 3 final rule. Therefore, we are choosing 

not to finalize these provisions at this time. We intend to finalize in-use fuel quality

standards for E51-83 and perhaps E16-50 as well in a follow-up final rule.

g. Regulatory Streamlining and Technical Amendments

This action also includes a number of items to help streamline the in-use fuels 

regulations at 40 CFR parts 79 and 80. The majority of these items involve clarifying 

vague or inconsistent language, removal or updating of outdated provisions, and 

decreasing in frequency and/or volume of reporting burden where data are no longer 

needed or are redundant with other EPA fuels programs. In general, we believe that these 

changes will reduce the burden on industry and allow the standards and resulting 

environmental benefits to be achieved as early as possible with no expected loss in 

environmental control. In some cases, these regulatory streamlining items are nonsubstantive amendments that correct minor errors or inconsistencies in the regulations.

The regulatory streamlining items that we are finalizing for the in-use fuels 

regulations are changes that we believe are straightforward and should be made quickly. 

This action also includes a variety of technical amendments to certificationrelated requirements for engine and vehicle emission standards; adjusting the fuel 

economy label provisions to correspond to the new Tier 3 standards, removing obsolete 

regulatory text, and making several minor corrections and clarifications. 

Please refer to Section VI for a complete discussion of technical amendments and 

regulatory streamlining provisions and issues.

C. What Will the Impacts of the Standards Be?

The final Tier 3 vehicle and fuel standards together will reduce dramatically 

emissions of NOX, VOC, PM2.5, and air toxics. The gasoline sulfur standards, which will

take effect in 2017, will provide large immediate reductions in emissions from existing 

gasoline vehicles and engines. NOX emissions are projected to be reduced by about 

260,000 tons, or about 10 percent of emissions from on-highway vehicles, in 2018, and 

these emission reductions will increase over time as newer vehicles become a larger 

percentage of the fleet. In 2030, when 70 percent of the miles travelled are projected to 

be from vehicles that meet the fully phased-in Tier 3 standards, we expect the NOX and 

VOC emissions to be reduced by about 330,000 tons and 170,000 tons, respectively, or 

25 percent and 16 percent of emissions from on-highway vehicles compared to their 2030 

levels without the Tier 3 program. Emissions of CO are projected to decrease by almost 

3.5 million tons, or 24 percent of emissions from on-highway vehicles. Emissions of 
Page 32 of 529

many air toxics will also be reduced, including benzene, 1,3-butadiene, acetaldehyde, 

formaldehyde, acrolein and ethanol, with reductions projected to range from 10 to nearly

30 percent of national emissions from on-highway vehicles. We expect these reductions 

to continue beyond 2030 as more of the fleet continues to turn over to Tier 3 vehicles; for 

example, by 2050, when nearly all of the fleet will have turned over to vehicles meeting 

the fully phased-in Tier 3 standards, we estimate the Tier 3 program will reduce onhighway emissions of NOX and VOC nearly 31 percent from the level of emissions 

projected without Tier 3 controls.16 

These reductions in emissions of NOX, VOC, PM2.5 and air toxics from the Tier 3 

standards are projected to lead to significant decreases in ambient concentrations of 

ozone, PM2.5 and air toxics (including notable nationwide reductions in benzene 

concentrations) by 2030, and will immediately reduce ozone in 2017 when the sulfur 

controls take effect. Additional information on the emission and air quality impacts of 

the final Tier 3 program is presented in Sections III.B and C. 

Exposure to ambient concentrations of ozone, PM2.5, and air toxics is linked to 

adverse human health impacts such as premature deaths as well as other important public 

health and environmental effects (see Section II.B). The final Tier 3 standards are 

expected to reduce these adverse impacts and yield significant benefits, including those 

we can monetize and those we are unable to quantify. We estimate that by 2030, the 

emission reductions of the Tier 3 standards will annually prevent between 660 and 1,500

PM-related premature deaths, between 110 and 500 ozone-related premature deaths, 

81,000 work days lost, 210,000 school absence days, and approximately 1.1 million 

minor restricted-activity days. The estimated annual monetized health benefits of the 

Tier 3 standards in 2030 (2011$) is between $7.4 and $19 billion, assuming a 3-percent 

discount rate (or between $6.7 billion and $18 billion assuming a 7-percent discount 

rate). We project the final fuel standards to cost on average 0.65 cent (i.e., less than a 

penny) per gallon of gasoline, and the final vehicle standards to have an average cost that 

increases in proportion to the increase in stringency during the phase-in period, from $28

per vehicle in 2017 to $72 per vehicle in 2025, when the standards are fully phased in. 

We estimate the annual cost of the overall program in 2030 will be approximately $1.5

billion, and the 2030 benefits will be between 4.5 and 13 times the costs of the program. 

The estimated benefits in Table I-6 include all of the human health impacts we are 

able to quantify and monetize at this time. However, the full complement of human 

health and welfare effects associated with PM, ozone and air toxics remain unquantified 

because of current limitations in methods and/or available data. As a result, the health 

benefits quantified in this section are likely underestimates of the total benefits 

attributable to the final standards. See Sections VII and VIII for detailed descriptions of 

the costs and benefits of this action. 

 

16 To estimate the benefits of the final Tier 3 rule, we performed air quality modeling for the year 2030. 
Page 33 of 529

Table I-6 Summary of Estimated Annual Benefits and Costs Associated with the 

Final Tier 3 Program (Billions, 2011$)a

Description 2030

Vehicle Program Costs

Fuels Program Costs

Total Estimated Costsb

$0.76

$0.70

$1.5

Total Estimated Health Benefitsc,d,e,f

 3 percent discount rate

 7 percent discount rate

$7.4 - $19

$6.7 - $18

Annual Net Benefits (Total Benefits – Total Costs)

 3 percent discount rate

 7 percent discount rate

$5.9 - $18

$5.2 - $17

Notes:

a All estimates represent annual benefits and costs anticipated for the year 2030. Totals are rounded to two 

significant digits and may not sum due to rounding.

b The calculation of annual costs does not require amortization of costs over time. Therefore, the estimates 

of annual cost do not include a discount rate or rate of return assumption (see Section VII of the preamble 

for more information on vehicle and fuel costs).

c Total includes ozone and PM2.5 estimated benefits. Range was developed by adding the estimate from the 

Bell et al., 2004 ozone premature mortality function to PM2.5-related premature mortality derived from the 

American Cancer Society cohort study (Krewski et al., 2009) for the low estimate and ozone premature 

mortality derived from the Levy et al., 2005 study to PM2.5-related premature mortality derived from the 

Six-Cities (Lepeule et al., 2012) study for the high estimate.

d Annual benefits analysis results reflect the use of a 3 percent and 7 percent discount rate in the valuation 

of premature mortality and nonfatal myocardial infarctions, consistent with EPA and OMB guidelines for 

preparing economic analyses. 

e Valuation of premature mortality based on long-term PM exposure assumes discounting over the SAB 

recommended 20-year segmented lag structure described in the Regulatory Impact Analysis for the 2012

PM National Ambient Air Quality Standards (December, 2012). 

f Not all possible benefits are quantified and monetized in this analysis; the total monetized benefits 

presented here may therefore be underestimated. Potential benefit categories that have not been quantified 

and monetized, due to current limitations in methods and/or data availability, are listed in Table VIII-2. For 

example, we have not quantified a number of known or suspected health and welfare effects linked with 

reductions in ozone and PM (e.g., reductions in heart rate variability, reduced material damage to structures 

and cultural monuments, and reduced eutrophication in coastal areas). We are also unable to quantify 

health and welfare benefits associated with reductions in air toxics.

II. Why Is EPA Taking this Action? 

The Clean Air Act authorizes EPA to establish emissions standards for motor 

vehicles to address air pollution that may reasonably be anticipated to endanger public 

health or welfare. EPA also has authority to establish fuel controls to address such air 

pollution. These statutory requirements are described in Section II.A.

Emissions from motor vehicles and their fuels contribute to ambient levels of 

ozone, PM, NO2, sulfur dioxide (SO2) and CO, which are all pollutants for which EPA 

has established health-based NAAQS. These pollutants are linked with respiratory and/or 
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cardiovascular problems and other adverse health impacts leading to increased 

medication use, hospital admissions, emergency department visits, and premature 

mortality. Over 149 million people currently live in areas designated nonattainment for 

one or more of the current NAAQS for ozone, PM2.5, PM10, and SO2.

17

 

Motor vehicles also emit air toxics, and the most recent available data indicate 

that the majority of Americans continue to be exposed to ambient concentrations of air 

toxics at levels which have the potential to cause adverse health effects, including cancer, 

immune system damage, and neurological, reproductive, developmental, respiratory, and 

other health problems.18 A more detailed discussion of the health and environmental 

effects of these pollutants is included in Section II.B. 

Cars and light trucks also continue to be a significant contributor to air pollution 

directly near roads, with gasoline vehicles accounting for more than 50 percent of nearroad concentrations of some criteria and toxic pollutants.19

 More than 50 million people 

live, work, or go to school in close proximity to high-traffic roadways, and the average 

American spends more than one hour traveling each day, with over 80 percent of daily

trips occurring by personal vehicle.20,21,22,23,24 Exposure to traffic-related pollutants has 

been linked with adverse health impacts such as respiratory problems (particularly in 

asthmatic children) and cardiovascular problems. 

In the absence of additional controls such as Tier 3 standards, many areas will 

continue to have ambient ozone and PM2.5 concentrations exceeding the NAAQS in the 

future. States and local areas are required to adopt control measures to attain the NAAQS 

 

17 Data come from Summary Nonattainment Area Population Exposure Report, current as of December 5, 

2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR2011-0135.

18 U.S. EPA. (2011) Summary of Results for the 2005 National-Scale Assessment. 

www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.

19 For example, see Fujita, E.M; Campbell, D.E.; Zielinska, B.; Arnott, W.P.; Chow, J.C. (2011) 

Concentrations of Air Toxics in Motor Vehicle-Dominated Environments. Health Effects Institute 

Research Report 156. Available at http://www.healtheffects.org

20 Rowangould, G.M. (2013) A census of the US near-roadway population: public health and 

environmental justice considerations. Transportation Research Part D 25: 59-67.

21 U.S. Census Bureau (2011). Current Housing Reports, Series H150/09, American Housing Survey for the 

United States: 2009. U.S. Government Printing Office, Washington, DC. Available at 

http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html

22 Drago, R.(2011). Secondary activities in the 2006 American Time Use Survey. U.S. Bureau of Labor 

Statistics Working Paper 446. Available at http://www.bls.gov

23 U.S. Department of Transportation, Bureau of Transportation Statistics. (2003) National Household 

Travel Survey 2001 Highlights Report. Government Printing Office, Washington, DC. Available at 

http://www.bts.gov/publications/highlights_of_the_2001_national_household_travel_survey/

24 Santos, A.; McGuckin, N, Yukiko Nakamoto, H.; Gray, D.; Liss, S. (2011) Summary of Travel Trends: 

2009 National Household Travel Survey. Federal Highway Administration report no FHWA-PL-11-022. 

Available at http://nhts.ornl.gov/publications.shtml.
Page 35 of 529

and, once attained, to demonstrate that control measures are in place sufficient to 

maintain the NAAQS for ten years (and eight years later, a similar demonstration is 

required for another ten-year period). The Tier 3 standards will be a critical part of many 

areas’ strategies to attain and maintain the NAAQS. Maintaining the NAAQS has been 

challenging for some areas in the past, particularly those where high population growth 

rates lead to significant annual increases in vehicle trips and vehicle miles traveled. Our 

air quality modeling for this final rule, which is described in more detail in Section III.C, 

projects that in 2018 a significant number of counties outside CA will be within 10 

percent of the 2008 ozone NAAQS, in the absence of additional controls. These counties 

in particular will benefit from the Tier 3 standards as they work to ensure long-term 

maintenance of the NAAQS. 

Section III provides more detail on how we expect this action will reduce motor 

vehicle emissions and ambient levels of pollution. We project that the Tier 3 program

will meaningfully reduce ozone concentrations as early as 2017 (the first year of the 

program), and even more significantly in 2030. The estimated reductions are of 

significant enough magnitude to bring ozone levels in some counties from above the 

standard to below the standard, even without any additional controls. We also project 

that the Tier 3 standards will reduce ambient PM2.5 concentrations. 

Without this action to reduce nationwide motor vehicle emissions, areas would 

have to adopt other measures to reduce emissions from other sources under their state or 

local authority. Few other measures exist for providing multi-pollutant reductions of the 

same magnitude and cost-effectiveness as those expected from the Tier 3 standards. 

Furthermore, most states do not have the authority to lower the sulfur in gasoline, which 

is needed to immediately reduce emissions from the existing fleet and also enable new 

vehicles to meet the Tier 3 emissions standards throughout their useful life. 

The projected reductions in ambient ozone and PM2.5 that will result from the Tier 

3 standards will provide significant health benefits. We estimate that by 2030, the 

standards will annually prevent between 660 and 1,500 PM-related premature deaths, 

between 110 and 500 ozone-related premature deaths, 81,000 work days lost, 210,000 

school absence days, and approximately 1.1 million minor restricted-activity days (see 

Section VIII for more details). This action will also reduce air toxics; for example, we 

project that in 2030, the Tier 3 standards will decrease ambient benzene concentrations 

by 10 - 25 percent in some urban areas. Furthermore, the Tier 3 standards will reduce 

traffic-associated pollution near major roads.

EPA is finalizing Tier 3 vehicle and fuel standards as part of a comprehensive 

nationwide program for regulating all types of air pollution from motor vehicles. EPA 

recently finalized standards to reduce GHG emissions from light-duty vehicles, starting 
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with model year 2017.25 The Tier 3 standards in this final rule, which address nonGHGs, will be implemented on the same timeframe, thus allowing manufacturers to 

optimize their vehicle redesigns over both sets of standards. Furthermore, the Tier 3 

vehicle and fuel standards are also closely aligned with California’s LEV III program, in 

such a way that manufacturers will be able to design a single vehicle for nationwide sales. 

This reduces the cost of compliance for auto manufacturers.

This Tier 3 rulemaking responds to the President’s request in his May 2010 

memorandum for EPA to review the adequacy of its existing non-GHG standards for new 

motor vehicles and fuels, and to promulgate new standards, if necessary, as part of a 

comprehensive approach to regulating motor vehicles.26 Based on our review, we have 

concluded that improved vehicle technology, combined with lower sulfur gasoline, make 

it feasible and cost-effective to reduce emissions well below the current Tier 2 levels. 

These emission reductions are necessary to reduce air pollution that is (and projected to 

continue to be) at levels that endanger public health and welfare.

A. Basis for Action under the Clean Air Act

1. Clean Air Act Section 202

We are setting motor vehicle emission standards under the authority of section 

202 of the Clean Air Act. Section 202(a) provides EPA with general authority to 

prescribe vehicle standards, subject to any specific limitations elsewhere in the Act. EPA 

is setting standards for larger light-duty trucks and MDPVs under the general authority of 

section 202(a)(1) and under section 202(a)(3), which requires that standards applicable to 

emissions of hydrocarbons, NOX, CO and PM from heavy-duty vehicles27 reflect the 

greatest degree of emission reduction available for the model year to which such 

standards apply, giving appropriate consideration to cost, energy, and safety. In addition, 

section 202(k) provides EPA with authority to issue and revise regulations applicable to 

evaporative emissions of hydrocarbons from all gasoline-fueled motor vehicles during: 

(1) operation, and (2) over 2 or more days of nonuse; under ozone-prone summertime 

conditions. Regulations under section 202(k) shall take effect as expeditiously as possible 

and shall require the greatest degree of emission reduction achievable by means 

reasonably expected to be available for production during any model year to which the 

regulations apply, giving appropriate consideration to fuel volatility, and to cost, energy, 

 

25 77 FR 62623 (October 15, 2012).

26 The Presidential Memorandum is found at: http://www.whitehouse.gov/the-press-office/presidentialmemorandum-regarding-fuel-efficiency-standards.

27 LDTs that have gross vehicle weight ratings above 6000 lbs and all MDPVs are considered ‘‘heavy-duty

vehicles’’ under the CAA. See section 202(b)(3)(C). For regulatory purposes, we generally refer to those 

LDTs which are above 6000 lbs GVWR and at or below 8500 lbs GVWR as ‘‘heavy light-duty trucks’’ 

made up of LDT3s and LDT4s, and we have defined MDPVs primarily as vehicles between 8500 and 

10000 lbs GVWR designed primarily for the transportation of persons. See 40 CFR 86.1803-01
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and safety factors associated with the application of the appropriate technology. Further, 

section 206 and in particular section 206(d) of the Clean Air Act authorizes EPA to 

establish methods and procedures for testing whether a motor vehicle or motor vehicle 

engine conforms with section 202 requirements.

2. Clean Air Act Section 211

We are adopting gasoline sulfur controls pursuant to our authority under section 

211(c)(1) of the CAA. This section allows EPA to establish a fuel control if at least one 

of the following two criteria is met: (1) The emission products of the fuel cause or 

contribute to air pollution which may reasonably be anticipated to endanger public health 

or welfare; or (2) the emission products of the fuel will impair to a significant degree the 

performance of any emissions control device or system which is either in general use or 

which the Administrator finds has been developed to a point where in a reasonable time it 

will be in general use were the fuel control to be adopted. We are finalizing gasoline 

sulfur controls based on both of these criteria. Under the first criterion, we believe that 

gasoline with current levels of sulfur contributes to ambient levels of air pollution that

endanger public health and welfare, as described in Section II.B. Under the second 

criterion, we believe that gasoline sulfur impairs the emissions control systems of 

vehicles, as discussed in Section III.A.2. 

B. Overview of Public Health Impacts of Motor Vehicles and Fuels 

Motor vehicles emit pollutants that contribute to ambient concentrations of ozone, 

PM, NO2, SO2, CO, and air toxics. Motor vehicles are significant contributors to 

emissions of VOC and NOX, which contribute to the formation of both ozone and PM2.5. 

Over 149 million people currently live in counties designated nonattainment for one or 

more of the NAAQS, and this figure does not include the people living in areas with a 

risk of exceeding the NAAQS in the future.28 The majority of Americans continue to be 

exposed to ambient concentrations of air toxics at levels which have the potential to cause 

adverse health effects.29 In addition, populations who live, work, or attend school near 

major roads experience elevated exposure concentrations to a wide range of air 

pollutants.30

EPA has already adopted many emission control programs that are expected to 

reduce ambient pollution concentrations. As a result of these programs, the number of 

 

28 Data come from Summary Nonattainment Area Population Exposure Report, current as of December 5, 

2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR2011-0135.

29 U.S. EPA. (2011) Summary of Results for the 2005 National-Scale Assessment. 

www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf. 

30

 Health Effects Institute Panel on the Health Effects of Traffic-Related Air Pollution. (2010) Trafficrelated air pollution: a critical review of the literature on emissions, exposure, and health effects. HEI 

Special Report 17. Available at http://www.healtheffects.org] 
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areas that continue to violate the ozone and PM2.5 NAAQS or have high levels of air 

toxics is expected to continue to decrease. However, the baseline air quality modeling 

completed for this rule predicts that without additional controls there will continue to be a 

need for reductions in ozone, PM2.5 and air toxics concentrations in some locations in the 

future. Section III.C of this preamble presents the air quality modeling results for this 

action. 

1. Ozone 

a. Background

Ground-level ozone pollution is typically formed through reactions involving 

VOC and NOX in the lower atmosphere in the presence of sunlight. These pollutants, 

often referred to as ozone precursors, are emitted by many types of pollution sources, 

such as highway and nonroad motor vehicles and engines, power plants, chemical plants, 

refineries, makers of consumer and commercial products, industrial facilities, and smaller 

area sources.

The science of ozone formation, transport, and accumulation is complex. 

Ground-level ozone is produced and destroyed in a cyclical set of chemical reactions, 

many of which are sensitive to temperature and sunlight. When ambient temperatures 

and sunlight levels remain high for several days and the air is relatively stagnant, ozone 

and its precursors can build up and result in more ozone than typically occurs on a single 

high-temperature day. Ozone and its precursors can be transported hundreds of miles 

downwind from precursor emissions, resulting in elevated ozone levels even in areas with 

low local VOC or NOX emissions.

b. Health Effects of Ozone

This section provides a summary of the health effects associated with exposure to 

ambient concentrations of ozone.

31

 The information in this section is based on the 

information and conclusions in the February 2013 Integrated Science Assessment for 

Ozone (Ozone ISA) prepared by EPA’s Office of Research and Development (ORD).

32

The Ozone ISA concludes that human exposures to ambient concentrations of ozone are 

associated with a number of adverse health effects and characterizes the weight of 

 

31

 Human exposure to ozone varies over time due to changes in ambient ozone concentration and because 

people move between locations which have notable different ozone concentrations. Also, the amount of 

ozone delivered to the lung is not only influenced by the ambient concentrations but also by the individuals 

breathing route and rate.

32

 U.S. EPA. Integrated Science Assessment of Ozone and Related Photochemical Oxidants (Final Report). 

U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-10/076F, 2013. The ISA is available 

at http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=247492#Download
Page 39 of 529

evidence for these health effects. 33 The discussion below highlights the Ozone ISA’s 

conclusions pertaining to health effects associated with both short-term and long-term 

periods of exposure to ozone.

For short-term exposure to ozone, the Ozone ISA concludes that respiratory

effects, including lung function decrements, pulmonary inflammation, exacerbation of 

asthma, respiratory-related hospital admissions, and mortality, are causally associated 

with ozone exposure. It also concludes that cardiovascular effects, including decreased 

cardiac function and increased vascular disease, and total mortality are likely to be 

causally associated with short-term exposure to ozone and that evidence is suggestive of 

a causal relationship between central nervous system effects and short-term exposure to 

ozone. 

For long-term exposure to ozone, the Ozone ISA concludes that respiratory

effects, including new onset asthma, pulmonary inflammation and injury, are likely to be 

a causally related with ozone exposure. The Ozone ISA characterizes the evidence as 

suggestive of a causal relationship for associations between long-term ozone exposure 

and cardiovascular effects, reproductive and developmental effects, central nervous 

system effects and total mortality. The evidence is inadequate to infer a causal 

relationship between chronic ozone exposure and increased risk of lung cancer.

Finally, interindividual variation in human responses to ozone exposure can result 

in some groups being at increased risk for detrimental effects in response to exposure. 

The Ozone ISA identified several groups that are at increased risk for ozone-related 

health effects. These groups are people with asthma, children and older adults, 

individuals with reduced intake of certain nutrients (i.e., Vitamins C and E), outdoor 

workers, and individuals having certain genetic variants related to oxidative metabolism 

or inflammation. Ozone exposure during childhood can have lasting effects through 

adulthood. Such effects include altered function of the respiratory and immune systems. 

Children absorb higher doses (normalized to lung surface area) of ambient ozone, 

compared to adults, due to their increased time spent outdoors, higher ventilation rates 

relative to body size, and a tendency to breathe a greater fraction of air through the 

mouth. Children also have a higher asthma prevalence compared to adults. Additional 

children’s vulnerability and susceptibility factors are listed in Section XII.G.

 

33 The ISA evaluates evidence and draws conclusions on the causal relationship between relevant pollutant 

exposures and health effects, assigning one of five “weight of evidence” determinations: causal 

relationship, likely to be a causal relationship, suggestive of a causal relationship, inadequate to infer a 

causal relationship, and not likely to be a causal relationship. For more information on these levels of 

evidence, please refer to Table II in the Preamble of the ISA. 
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c. Current and Projected Concentrations of Ozone 

Concentrations that exceed the level of the ozone NAAQS occur in many parts of 

the country, including major population centers such as Atlanta, Baltimore, Chicago, 

Dallas, Houston, New York, Philadelphia, and Washington, D.C. In addition, our 

modeling without the Tier 3 controls projects that in the future we will continue to have 

many counties that will have ambient ozone concentrations above the level of the 

NAAQS (see Section III.C.1). States will need to meet the standard in the 2015-2032 

time frame for the 2008 ozone NAAQS. The emission reductions and significant ambient 

ozone improvements from this rule, which will take effect starting in 2017, will be 

helpful to states as they work to attain and maintain the ozone NAAQS.

The primary and secondary NAAQS for ozone are 8-hour standards with a level 

of 0.075 ppm. The most recent revision to the ozone standards was in 2008; the previous 

8-hour ozone standards, set in 1997, had a level of 0.08 ppm. In 2004, the U.S. EPA 

designated nonattainment areas for the 1997 8-hour ozone NAAQS.34,35 As of December 

5, 2013, there were 39 ozone nonattainment areas for the 1997 ozone NAAQS composed 

of 216 full or partial counties with a total population of over 112 million. Nonattainment 

designations for the 2008 ozone standard were finalized on April 30, 2012 and May 31, 

2012.36 As of December 5, 2013, there were 46 ozone nonattainment areas for the 2008

ozone NAAQS, composed of 227 full or partial counties, with a population of over 123 

million. As of December 5, 2013, over 135 million people are living in ozone 

nonattainment areas.37 

States with ozone nonattainment areas are required to take action to bring those 

areas into attainment. The attainment date assigned to an ozone nonattainment area is 

based on the area’s classification. Most ozone nonattainment areas were required to 

attain the 1997 8-hour ozone NAAQS in the 2007 to 2013 time frame and then to 

maintain it thereafter.38 The attainment dates for areas designated nonattainment for the 

2008 8-hour ozone NAAQS are in the 2015 to 2032 timeframe, depending on the severity 

of the problem in each area. In addition, EPA is currently working on a review of the 

 

34 69 FR 23858 (April 30, 2004).

35 A nonattainment area is defined in the Clean Air Act (CAA) as an area that is violating an ambient 

standard or is contributing to a nearby area that is violating the standard.

36 77FR 30088 (May 21, 2012) and 77 FR 34221 (June 11, 2012).

37 The 135 million total is calculated by summing, without double counting, the 1997 and 2008 ozone 

nonattainment populations contained in the Summary Nonattainment Area Population Exposure report 

(http://www.epa.gov/oar/oaqps/greenbk/popexp.html). If there is a population associated with both the 

1997 and 2008 nonattainment areas, and they are not the same, then the larger of the two populations is 

included in the sum.

38 The Los Angeles South Coast Air Basin 8-hour ozone nonattainment area and the San Joaquin Valley Air 

Basin 8-hour ozone nonattainment area are designated as Extreme and will have to attain before June 15, 

2024. The Sacramento, Coachella Valley, Western Mojave and Houston 8-hour ozone nonattainment areas 

are designated as Severe and will have to attain by June 15, 2019. 
Page 41 of 529

ozone NAAQS. If EPA revises the ozone standards pursuant to that review, the 

attainment dates associated with areas designated nonattainment for that NAAQS would 

be 5 or more years after the final rule is promulgated, depending on the severity of the 

problem in each area. 

EPA has already adopted many emission control programs that are expected to 

reduce ambient ozone levels. As a result of these and other federal, state and local 

programs, 8-hour ozone levels are expected to improve in the future. However, even 

with the implementation of all current state and federal regulations, there are projected to 

be counties violating the ozone NAAQS well into the future. Thus additional federal 

control programs, such as Tier 3, can assist areas with attainment dates in 2018 and 

beyond in attaining the NAAQS as expeditiously as practicable and may relieve areas 

with already stringent local regulations from some of the burden associated with adopting 

additional local controls.

2. Particulate Matter

a. Background

Particulate matter is a highly complex mixture of solid particles and liquid 

droplets distributed among numerous atmospheric gases which interact with solid and 

liquid phases. Particles range in size from those smaller than 1 nanometer (10-9 meter) to 

over 100 micrometer (μm, or 10-6 meter) in diameter (for reference, a typical strand of 

human hair is 70 μm in diameter and a grain of salt is about 100 μm). Atmospheric 

particles can be grouped into several classes according to their aerodynamic and physical 

sizes, including ultrafine particles (<0.1 μm), accumulation mode or ‘fine’ particles (<1 

to 3 μm), and coarse particles (>1 to 3 μm).39 For regulatory purposes, fine particles are 

measured as PM2.5 and inhalable or thoracic coarse particles are measured as PM10-2.5, 

corresponding to their size (diameter) range in micrometers. The EPA currently has 

standards that measure PM2.5 and PM10.

40

 

Particles span many sizes and shapes and may consist of hundreds of different 

chemicals. Particles are emitted directly from sources and are also formed through 

atmospheric chemical reactions; the former are often referred to as “primary” particles, 

and the latter as “secondary” particles. Particle concentration and composition varies by 

time of year and location, and in addition to differences in source emissions, is affected 

 

39 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. Figure 3-1.

40 Regulatory definitions of PM size fractions, and information on reference and equivalent methods for 

measuring PM in ambient air, are provided in 40 CFR Parts 50, 53, and 58. With regard to national 

ambient air quality standards (NAAQS) which provide protection against health and welfare effects, the 24-

hour PM10 standard provides protection against effects associated with short-term exposure to thoracic 

coarse particles (i.e., PM10-2.5).
Page 42 of 529

by several weather-related factors, such as temperature, clouds, humidity, and wind. A 

further layer of complexity comes from particles’ ability to shift between solid/liquid and 

gaseous phases, which is influenced by concentration and meteorology, especially 

temperature. 

Fine particles are produced primarily by combustion processes and by 

transformations of gaseous emissions (e.g., sulfur oxides (SOX), oxides of nitrogen, and 

volatile organic compounds (VOC)) in the atmosphere. The chemical and physical 

properties of PM2.5 may vary greatly with time, region, meteorology, and source 

category. Thus, PM2.5 may include a complex mixture of different components including 

sulfates, nitrates, organic compounds, elemental carbon and metal compounds. These 

particles can remain in the atmosphere for days to weeks and travel hundreds to 

thousands of kilometers.

b. Health Effects of PM

Scientific studies show ambient PM is associated with a broad range of health 

effects. These health effects are discussed in detail in the December 2009 Integrated 

Science Assessment for Particulate Matter (PM ISA).

41

 The PM ISA summarizes health 

effects evidence associated with both short- and long-term exposures to PM2.5, PM10-2.5, 

and ultrafine particles. The PM ISA concludes that human exposures to ambient PM2.5

concentrations are associated with a number of adverse health effects and characterizes 

the weight of evidence for these health outcomes.42 The discussion below highlights the 

PM ISA’s conclusions pertaining to health effects associated with both short- and longterm PM exposures. Further discussion of health effects associated with PM2.5 can also 

be found in the rulemaking documents for the most recent review of the PM NAAQS 

completed in 2012.

43,44

The EPA concludes that a causal relationship exists between both long- and shortterm exposures to PM2.5 and premature mortality and cardiovascular effects and a likely

causal relationship exists between long- and short-term PM2.5 exposures and respiratory 

effects. Further, there is evidence suggestive of a causal relationship between long-term 

 

41 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. 

42 The causal framework draws upon the assessment and integration of evidence from across 

epidemiological, controlled human exposure, and toxicological studies, and the related uncertainties that 

ultimately influence our understanding of the evidence. This framework employs a five-level hierarchy 

that classifies the overall weight of evidence and causality using the following categorizations: causal 

relationship, likely to be causal relationship, suggestive of a causal relationship, inadequate to infer a causal 

relationship, and not likely to be a causal relationship (U.S. EPA. (2009). Integrated Science Assessment 

for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, 

EPA/600/R-08/139F, Table 1–3). 

43 78 FR 3086 (January 15, 2013), pages 3103-3104.

44 77 FR 38890 (June 29, 2012), pages 38906-38911.
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PM2.5 exposures and other health effects, including developmental and reproductive 

effects (e.g., low birth weight, infant mortality) and carcinogenic, mutagenic, and 

genotoxic effects (e.g., lung cancer mortality).45

As summarized in the Final PM NAAQS rule, and discussed extensively in the 

2009 PM ISA, the scientific evidence available since the completion of the 2006 PM 

NAAQS review significantly strengthens the link between long- and short-term exposure 

to PM2.5 and premature mortality, while providing indications that the magnitude of the 

PM2.5- mortality association with long-term exposures may be larger than previously

estimated. 46,47 The strongest evidence comes from recent studies investigating long-term 

exposure to PM2.5 and cardiovascular-related mortality. The evidence supporting a causal 

relationship between long-term PM2.5 exposure and mortality also includes consideration 

of new studies that demonstrated an improvement in community health following 

reductions in ambient fine particles.48

Several studies evaluated in the 2009 PM ISA have examined the association 

between cardiovascular effects and long-term PM2.5 exposures in multi-city studies 

conducted in the U.S. and Europe. While studies were not available in the 2006 PM 

NAAQS review with regard to long-term exposure and cardiovascular-related morbidity, 

studies published since then have provided new evidence linking long-term exposure to 

PM2.5 with an array of cardiovascular effects such as heart attacks, congestive heart 

failure, stroke, and mortality. This evidence is coherent with studies of short-term 

exposure to PM2.5 that have observed associations with a continuum of effects ranging 

from subtle changes in indicators of cardiovascular health to serious clinical events, such 

as increased hospitalizations and emergency department visits due to cardiovascular 

disease and cardiovascular mortality.

49

As detailed in the 2009 PM ISA, extended analyses of studies available in the 

2006 PM NAAQS review as well as epidemiological studies conducted in the U.S. and 

abroad published since then provide stronger evidence of respiratory-related morbidity

effects associated with long-term PM2.5 exposure. The strongest evidence for respiratoryrelated effects is from studies that evaluated decrements in lung function growth (in 

children), increased respiratory symptoms, and asthma development. The strongest 

 

45 These causal inferences are based not only on the more expansive epidemiological evidence available in

this review but also reflect consideration of important progress that has been made to advance our 

understanding of a number of potential biologic modes of action or pathways for PM-related cardiovascular 

and respiratory effects (U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final 

Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, chapter 5).

46 78 FR 3103-3104 (January 15, 2013).

47 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, chapter 6 (Section 6.5) and 

chapter 7 (Section 7.6).

48 78 FR 3103 (January 15, 2013).

49 78 FR 3103 (January 15, 2013).
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evidence from short-term PM2.5 exposure studies has been observed for increased 

respiratory-related emergency department visits and hospital admissions for chronic 

obstructive pulmonary disease (COPD) and respiratory infections.50

The body of scientific evidence detailed in the 2009 PM ISA is still limited with 

respect to associations between long-term PM2.5 exposures and developmental and 

reproductive effects as well as cancer, mutagenic, and genotoxic effects, but is somewhat 

expanded from the 2006 review. The strongest evidence for an association between 

PM2.5 and developmental and reproductive effects comes from epidemiological studies of 

low birth weight and infant mortality, especially due to respiratory causes during the 

post-neonatal period (i.e., 1 month to 12 months of age). 51 With regard to cancer effects, 

‘‘[m]ultiple epidemiologic studies have shown a consistent positive association between 

PM2.5 and lung cancer mortality, but studies have generally not reported associations 

between PM2.5 and lung cancer incidence.’’53

Specific groups within the general population are at increased risk for 

experiencing adverse health effects related to PM exposures.54,55,56, 57 The evidence 

detailed in the 2009 PM ISA expands our understanding of previously identified at-risk 

populations and lifestages (i.e., children, older adults, and individuals with pre-existing 

heart and lung disease) and supports the identification of additional at-risk populations 

(e.g., persons with lower socioeconomic status, genetic differences). Additionally, there 

is emerging, though still limited, evidence for additional potentially at-risk populations

and lifestages, such as those with diabetes, people who are obese, pregnant women, and

the developing fetus. 60

For PM10-2.5, the 2009 PM ISA concluded that available evidence was suggestive 

of a causal relationship between short-term exposures to PM10-2.5 and cardiovascular 

effects (e.g., hospital admissions and ED visits, changes in cardiovascular function), 

respiratory effects (e.g, ED visits and hospital admissions, increase in markers of 

 

50 78 FR 3103-3104 (January 15, 2013).

51 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, chapter 2 (section 2.3.1 and 

2.3.2) and chapter 7.

53 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. pg 2-13

54 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. Chapter 8 and Chapter 2.

55 77 FR 38890 (June 29, 2012).

56 78 FR 3104 (January 15, 2013).

57 U.S. EPA. (2011). Policy Assessment for the Review of the PM NAAQS. U.S. Environmental 

Protection Agency, Washington, DC, EPA/452/R-11-003. section 2.2.1.

60 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. Chapter 8 and Chapter 2 

(Section 2.4.1).
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pulmonary inflammation), and premature mortality. Data were inadequate to draw 

conclusions regarding the relationships between long-term exposure to PM10-2.5 and 

various health effects. 61,62,63

For ultrafine particles, the 2009 PM ISA concluded that the evidence was 

suggestive of a causal relationship between short-term exposures and cardiovascular 

effects, including changes in heart rhythm and vasomotor function (the ability of blood 

vessels to expand and contract). It also concluded that there was evidence suggestive of a 

causal relationship between short-term exposure to ultrafine particles and respiratory

effects, including lung function and pulmonary inflammation, with limited and 

inconsistent evidence for increases in ED visits and hospital admissions. Data were 

inadequate to draw conclusions regarding the relationship between short-term exposure to 

ultrafine particle and additional health effects including premature mortality as well as 

long-term exposure to ultrafine particles and all health outcomes evaluated.

64,65

c. Current and Projected Concentrations of PM2.5

There are two primary NAAQS for PM2.5: an annual standard (12.0 micrograms 

per cubic meter (μg/m3)) and a 24-hour standard (35 μg/m3), and two secondary NAAQS 

for PM2.5: an annual standard (15.0 μg/m3) and a 24-hour standard (35 μg/m3). The initial 

PM2.5 standards were set in 1997 and revisions to the standards were finalized in 2006 

and in December 2012. The December 2012 rule revised the level of the primary annual 

PM2.5 standard from 15.0 μg/m3to 12.0 μg/m3.

66

There are many areas of the country that are currently in nonattainment for the 

annual and 24-hour PM2.5 NAAQS. Our modeling without the Tier 3 controls projects 

that in the future we will continue to have many areas that will have ambient PM2.5

concentrations above the level of the NAAQS (see Section III.C.2). States will need to 

meet the 2006 24-hour standards in the 2015-2019 timeframe and the 2012 primary

annual standard in the 2021-2025 timeframe. The emission reductions and improvements 

in ambient PM2.5 concentrations from this action, which will take effect starting in 2017, 

will be helpful to states as they work to attain and maintain the PM2.5 NAAQS.

 

61 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. Section 2.3.4 and Table 2-6.

62 78 FR 3167-8 (January 15, 2013).

63 77 FR 38947-51 (June 29, 2012).

64 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. Section 2.3.5 and Table 2-6.

65 78 FR 3121 (January 15, 2013).

66 U.S. EPA (2012). National Ambient Air Quality Standards for Particulate Matter. 

http://www.epa.gov/PM/2012/finalrule.pdf. 78 FR 3164
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In 2005 the EPA designated 39 nonattainment areas for the 1997 PM2.5

NAAQS.67 As of December 5, 2013, over 68 million people lived in the 24 areas that are 

still designated as nonattainment for the 1997 annual PM2.5 NAAQS. These PM2.5

nonattainment areas are comprised of 135 full or partial counties. EPA anticipates 

making initial area designation decisions for the 2012 primary annual PM2.5 NAAQS in

December 2014, with those designations likely becoming effective in early 2015.68 On 

November 13, 2009 and February 3, 2011, the EPA designated 32 nonattainment areas 

for the 2006 24-hour PM2.5 NAAQS.69 As of December 5, 2013, 28 of these areas remain 

designated as nonattainment, and they are composed of 104 full or partial counties with a 

population of over 65 million. In total, there are currently 39 PM2.5 nonattainment areas 

with a population of over 84 million people.70 

States with PM2.5 nonattainment areas will be required to take action to bring 

those areas into attainment in the future. Designated nonattainment areas not currently 

attaining the 1997 annual PM2.5 NAAQS are required to attain the NAAQS by 2015 and 

will be required to maintain the 1997 annual PM2.5 NAAQS thereafter. The 2006 24-

hour PM2.5 nonattainment areas are required to attain the 2006 24-hour PM2.5 NAAQS in 

the 2015 to 2019 time frame and will be required to maintain the 2006 24-hour PM2.5

NAAQS thereafter. Areas to be designated nonattainment for the 2012 primary annual 

PM2.5 NAAQS will likely be required to attain the 2012 NAAQS in the 2021 to 2025 

time frame. The Tier 3 standards finalized here begin taking effect in 2017. 

The EPA has already adopted many mobile source emission control programs that 

are expected to reduce ambient PM concentrations. As a result of these and other federal, 

state and local programs, the number of areas that fail to meet the PM2.5 NAAQS in the 

future is expected to decrease. However, even with the implementation of all current 

state and federal regulations, there are projected to be counties violating the PM2.5

NAAQS well into the future. Thus additional federal control programs, such as Tier 3, 

can assist areas with attainment dates in 2017 and beyond in attaining the NAAQS as 

expeditiously as practicable and may relieve areas with already stringent local regulations 

from some of the burden associated with adopting additional local controls.

d. Current Concentrations of PM10

In the December 2012 action in which the EPA promulgated the revised primary

annual PM2.5 NAAQS, the EPA also retained the existing primary and secondary 24-hour 

 

67 70 FR 19844 (April 14, 2005).

68 U.S. EPA (2012). Fact Sheet: Implementing the Standards. 

http://www.epa.gov/airquality/particlepollution/2012/decfsimp.pdf

69 74 FR 58688 (November 13, 2009) and 76 FR 6056 (February 3, 2011).

70

 Data come from Summary Nonattainment Area Population Exposure Report, current as of July 31, 2013

at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR-2011-

0135. 
Page 47 of 529

PM10 standards at 150 μg/m3. As of December 5, 2013, over 11 million people live in the 

40 areas that are designated as nonattainment for the PM10 NAAQS. There are 33 full or 

partial counties that make up the PM10 nonattainment areas.

3. Oxides of Nitrogen and Sulfur

a. Background

Nitrogen dioxide (NO2) is a member of the NOX family of gases. Most NO2 is 

formed in the air through the oxidation of nitric oxide (NO) emitted when fuel is burned 

at a high temperature. Sulfur dioxide (SO2), a member of the sulfur oxide (SOX) family 

of gases, is formed from burning fuels containing sulfur (e.g., coal or oil derived), 

extracting gasoline from oil, or extracting metals from ore. 

SO2 and NO2 and their gas phase oxidation products can dissolve in water 

droplets and further oxidize to form sulfuric and nitric acid which react with ammonia to 

form sulfates and nitrates, both of which are important components of ambient PM. The 

health effects of ambient PM are discussed in Section II.B.2.b of this preamble. NOX and 

VOC are the two major precursors of ozone. The health effects of ozone are covered in 

Section II.B.2.1.b.

b. Health Effects of NO2

The most recent review of the health effects of oxides of nitrogen completed by

the EPA can be found in the 2008 Integrated Science Assessment for Nitrogen Oxides

(NOX ISA).

71

 The EPA concluded that the findings of epidemiologic, controlled human 

exposure, and animal toxicological studies provide evidence that is sufficient to infer a 

likely causal relationship between respiratory effects and short-term NO2 exposure. The

2008 NOX ISA concluded that the strongest evidence for such a relationship comes from 

epidemiologic studies of respiratory effects including increased respiratory symptoms, 

emergency department visits, and hospital admissions. Based on both short- and longterm exposure studies, the 2008 NOX ISA concluded that individuals with preexisting 

pulmonary conditions (e.g., asthma or COPD), children, and older adults are potentially

at greater risk of NO2-related respiratory effects. Based on findings from controlled 

human exposure studies, the 2008 NOX ISA also drew two broad conclusions regarding 

airway responsiveness following NO2 exposure. First, the NOX ISA concluded that NO2

exposure may enhance the sensitivity to allergen-induced decrements in lung function 

and increase the allergen-induced airway inflammatory response following 30-minute

exposures of asthmatic adults to NO2 concentrations as low as 260 ppb. Second, 

exposure to NO2 has been found to enhance the inherent responsiveness of the airway to 

subsequent nonspecific challenges in controlled human exposure studies of healthy and 

 

71 U.S. EPA (2008). Integrated Science Assessment for Oxides of Nitrogen – Health Criteria (Final 

Report). EPA/600/R-08/071. Washington, DC: U.S.EPA. 
Page 48 of 529

asthmatic adults. Small but statistically significant increases in nonspecific airway

hyperresponsiveness were reported for asthmatic adults following 30-minute exposures to 

200-300 ppb NO2 and following 1-hour exposures of asthmatics to 100 ppb NO2. 

Enhanced airway responsiveness could have important clinical implications for 

asthmatics since transient increases in airway responsiveness following NO2 exposure 

have the potential to increase symptoms and worsen asthma control. Together, the 

epidemiologic and experimental data sets form a plausible, consistent, and coherent 

description of a relationship between NO2 exposures and an array of adverse health 

effects that range from the onset of respiratory symptoms to hospital admission. 

In evaluating a broader range of health effects, the 2008 NOX ISA concluded 

evidence was “suggestive but not sufficient to infer a causal relationship” between shortterm NO2 exposure and premature mortality and between long-term NO2 exposure and 

respiratory effects. The latter was based largely on associations observed between longterm NO2 exposure and decreases in lung function growth in children. Furthermore, the 

2008 NOX ISA concluded that evidence was “inadequate to infer the presence or absence 

of a causal relationship” between short-term NO2 exposure and cardiovascular effects as 

well as between long-term NO2 exposure and cardiovascular effects, reproductive and 

developmental effects, premature mortality, and cancer.72 The conclusions for these 

health effect categories were informed by uncertainties in the evidence base such as the 

independent effects of NO2 exposure within the broader mixture of traffic-related 

pollutants, limited evidence from experimental studies, and/or an overall limited literature 

base.

c. Health Effects of SO2

Information on the health effects of SO2 can be found in the 2008 Integrated 

Science Assessment for Sulfur Oxides (SO2 ISA).

73

 Short-term peaks of SO2 have long 

been known to cause adverse respiratory health effects, particularly among individuals 

with asthma. In addition to those with asthma (both children and adults), potentially

sensitive groups include all children and the elderly. During periods of elevated 

ventilation, asthmatics may experience symptomatic bronchoconstriction within minutes 

of exposure. Following an extensive evaluation of health evidence from epidemiologic 

and laboratory studies, the EPA concluded that there is a causal relationship between 

respiratory health effects and short-term exposure to SO2. Separately, based on an 

evaluation of the epidemiologic evidence of associations between short-term exposure to 

SO2 and mortality, the EPA concluded that the overall evidence is suggestive of a causal 

relationship between short-term exposure to SO2 and mortality.

 

72 U.S. EPA (2008). Integrated Science Assessment for Oxides of Nitrogen – Health Criteria (Final 

Report). EPA/600/R-08/071. Washington, DC: U.S.EPA.

73 U.S. EPA. (2008). Integrated Science Assessment (ISA) for Sulfur Oxides – Health Criteria (Final 

Report). EPA/600/R-08/047F. Washington, DC: U.S. Environmental Protection Agency.
Page 49 of 529

d. Current Concentrations of NO2

The EPA most recently completed a review of the primary NAAQS for NO2 in 

January 2010. There are two primary NAAQS for NO2: an annual standard (53 ppb) and 

a 1-hour standard (100 ppb). The EPA promulgated area designations in the Federal 

Register on February 17, 2012. In this initial round of designations, all areas of the 

country were designated as “unclassifiable/attainment” for the 2010 NO2 NAAQS based 

on data from the existing air quality monitoring network. The EPA and state agencies are 

working to establish an expanded network of NO2 monitors, expected to be deployed in 

the 2014-2017 time frame. Once three years of air quality data have been collected from 

the expanded network, the EPA will be able to evaluate NO2 air quality in additional 

locations.

74,75

e. Current Concentrations of SO2

The EPA most recently completed a review of the primary SO2 NAAQS in June 

2010. The current primary NAAQS for SO2 is a 1-hour standard of 75 ppb. The EPA 

finalized the initial area designations for 29 nonattainment areas in 16 states in a notice 

published in the Federal Register on August 5, 2013. In this first round of designations, 

EPA only designated nonattainment areas that were violating the standard based on 

existing air quality monitoring data provided by the states. The Agency did not have 

sufficient information to designate any area as “attainment” or make final decisions about 

areas for which additional modeling or monitoring is needed (78 FR 47191, August 5, 

2013). EPA anticipates designating areas for the revised SO2 standard in multiple 

rounds.

4. Carbon Monoxide

Carbon monoxide (CO) is a colorless, odorless gas emitted from combustion 

processes. Nationally and, particularly in urban areas, the majority of CO emissions to 

ambient air come from mobile sources.

a. Health Effects of Carbon Monoxide

Information on the health effects of CO can be found in the January 2010

Integrated Science Assessment for Carbon Monoxide (CO ISA).

76

 The CO ISA 

 

74 U.S. EPA. (2012). Fact Sheet – Air Quality Designations for the 2010 Primary Nitrogen Dioxide (NO2) 

National Ambient Air Quality Standards. 

http://www.epa.gov/airquality/nitrogenoxides/designations/pdfs/20120120FS.pdf

75 U.S. Environmental Protection Agency (2013). Revision to Ambient Nitrogen Dioxide Monitoring 

Requirements. March 7, 2013. http://www.epa.gov/airquality/nitrogenoxides/pdfs/20130307fr.pdf

76 U.S. EPA, (2010). Integrated Science Assessment for Carbon Monoxide (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-09/019F, 2010. Available at

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=218686. 
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concludes that ambient concentrations of CO are associated with a number of adverse 

health effects.77 This section provides a summary of the health effects associated with 

exposure to ambient concentrations of CO.78 

Controlled human exposure studies of subjects with coronary artery disease show 

a decrease in the time to onset of exercise-induced angina (chest pain) and 

electrocardiogram changes following CO exposure. In addition, epidemiologic studies 

show associations between short-term CO exposure and cardiovascular morbidity, 

particularly increased emergency room visits and hospital admissions for coronary heart 

disease (including ischemic heart disease, myocardial infarction, and angina). Some 

epidemiologic evidence is also available for increased hospital admissions and 

emergency room visits for congestive heart failure and cardiovascular disease as a whole. 

The CO ISA concludes that a causal relationship is likely to exist between short-term 

exposures to CO and cardiovascular morbidity. It also concludes that available data are 

inadequate to conclude that a causal relationship exists between long-term exposures to 

CO and cardiovascular morbidity. 

Animal studies show various neurological effects with in-utero CO exposure. 

Controlled human exposure studies report central nervous system and behavioral effects 

following low-level CO exposures, although the findings have not been consistent across 

all studies. The CO ISA concludes the evidence is suggestive of a causal relationship 

with both short- and long-term exposure to CO and central nervous system effects.

A number of studies cited in the CO ISA have evaluated the role of CO exposure 

in birth outcomes such as preterm birth or cardiac birth defects. The epidemiologic 

studies provide limited evidence of a CO-induced effect on preterm births and birth 

defects, with weak evidence for a decrease in birth weight. Animal toxicological studies 

have found perinatal CO exposure to affect birth weight, as well as other developmental 

outcomes. The CO ISA concludes the evidence is suggestive of a causal relationship 

between long-term exposures to CO and developmental effects and birth outcomes.

Epidemiologic studies provide evidence of associations between ambient CO 

concentrations and respiratory morbidity such as changes in pulmonary function, 

respiratory symptoms, and hospital admissions. A limited number of epidemiologic 

studies considered copollutants such as ozone, SO2, and PM in two-pollutant models and 

found that CO risk estimates were generally robust, although this limited evidence makes 

 

77 The ISA evaluates the health evidence associated with different health effects, assigning one of five 

“weight of evidence” determinations: causal relationship, likely to be a causal relationship, suggestive of a 

causal relationship, inadequate to infer a causal relationship, and not likely to be a causal relationship. For 

definitions of these levels of evidence, please refer to Section 1.6 of the ISA. 

78 Personal exposure includes contributions from many sources, and in many different environments. Total 

personal exposure to CO includes both ambient and nonambient components; and both components may 

contribute to adverse health effects.
Page 51 of 529

it difficult to disentangle effects attributed to CO itself from those of the larger complex 

air pollution mixture. Controlled human exposure studies have not extensively evaluated 

the effect of CO on respiratory morbidity. Animal studies at levels of 50-100 ppm CO 

show preliminary evidence of altered pulmonary vascular remodeling and oxidative 

injury. The CO ISA concludes that the evidence is suggestive of a causal relationship 

between short-term CO exposure and respiratory morbidity, and inadequate to conclude 

that a causal relationship exists between long-term exposure and respiratory morbidity. 

Finally, the CO ISA concludes that the epidemiologic evidence is suggestive of a 

causal relationship between short-term concentrations of CO and mortality. 

Epidemiologic studies provide evidence of an association between short-term exposure to 

CO and mortality, but limited evidence is available to evaluate cause-specific mortality

outcomes associated with CO exposure. In addition, the attenuation of CO risk estimates 

which was often observed in copollutant models contributes to the uncertainty as to 

whether CO is acting alone or as an indicator for other combustion-related pollutants. The

CO ISA also concludes that there is not likely to be a causal relationship between 

relevant long-term exposures to CO and mortality.

b. Current Concentrations of CO

There are two NAAQS for CO: an 8-hour standard (9 ppm) and a 1-hour standard 

(35 ppm). The primary NAAQS for CO were retained in August 2011. There are 

currently no CO nonattainment areas; as of September 27, 2010, all CO nonattainment 

areas were redesignated to maintenance areas. The designations were based on the 

existing community-wide monitoring network. EPA is making changes to the ambient 

air monitoring requirements for CO. The new requirements are expected to result in 

approximately 52 CO monitors operating near roads within 52 urban areas by January

2015 (76 FR 54294, August 31, 2011). 

5. Mobile Source Air Toxics

Light-duty vehicle emissions contribute to ambient levels of air toxics known or 

suspected as human or animal carcinogens, or that have noncancer health effects. The 

population experiences an elevated risk of cancer and other noncancer health effects from 

exposure to the class of pollutants known collectively as “air toxics.”79 These 

compounds include, but are not limited to, benzene, 1,3-butadiene, formaldehyde, 

acetaldehyde, acrolein, polycyclic organic matter, and naphthalene. These compounds 

were identified as national or regional risk drivers or contributors in the 2005 National-

 

79 U.S. EPA. (2011) Summary of Results for the 2005 National-Scale Assessment. 

www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf. 
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scale Air Toxics Assessment and have significant inventory contributions from mobile 

sources.80 

a. Health Effects of Air Toxics

i. Benzene

The EPA’s Integrated Risk Information System (IRIS) database lists benzene as a 

known human carcinogen (causing leukemia) by all routes of exposure, and concludes 

that exposure is associated with additional health effects, including genetic changes in 

both humans and animals and increased proliferation of bone marrow cells in mice.81,82,83 

EPA states in its IRIS database that data indicate a causal relationship between benzene 

exposure and acute lymphocytic leukemia and suggest a relationship between benzene 

exposure and chronic non-lymphocytic leukemia and chronic lymphocytic leukemia. 

EPA’s IRIS documentation for benzene also lists a range of 2.2 x 10-6to 7.8 x 10-6as the 

unit risk estimate (URE) for benzene.84,85 The International Agency for Research on 

Carcinogens (IARC) has determined that benzene is a human carcinogen and the U.S. 

Department of Health and Human Services (DHHS) has characterized benzene as a 

known human carcinogen.86,87 

A number of adverse noncancer health effects including blood disorders, such as 

preleukemia and aplastic anemia, have also been associated with long-term exposure to 

benzene.88,89 The most sensitive noncancer effect observed in humans, based on current 

 

80 U.S. EPA (2011) 2005 National-Scale Air Toxics Assessment. http://www.epa.gov/ttn/atw/nata2005. 

81 U.S. EPA. (2000). Integrated Risk Information System File for Benzene. This material is available 

electronically at: http://www.epa.gov/iris/subst/0276.htm. 

82 International Agency for Research on Cancer, IARC monographs on the evaluation of carcinogenic risk 

of chemicals to humans, Volume 29, Some industrial chemicals and dyestuffs, International Agency for 

Research on Cancer, World Health Organization, Lyon, France 1982. 

83 Irons, R.D.; Stillman, W.S.; Colagiovanni, D.B.; Henry, V.A. (1992). Synergistic action of the benzene 

metabolite hydroquinone on myelopoietic stimulating activity of granulocyte/macrophage colonystimulating factor in vitro, Proc. Natl. Acad. Sci. 89:3691-3695. 

84 A unit risk estimate is defined as the increase in the lifetime risk of an individual who is exposed for a 

lifetime to 1 μg/m3 benzene in air.

85 U.S. EPA. (2000). Integrated Risk Information System File for Benzene. This material is available 

electronically at: http://www.epa.gov/iris/subst/0276.htm. 

86 International Agency for Research on Cancer (IARC). (1987). Monographs on the evaluation of 

carcinogenic risk of chemicals to humans, Volume 29, Supplement 7, Some industrial chemicals and 

dyestuffs, World Health Organization, Lyon, France.

87 U.S. Department of Health and Human Services National Toxicology Program. (2011). 12th Report on 

Carcinogens. Available at: http://ntp.niehs.nih.gov/?objectid=03C9AF75-E1BF-FF40-

DBA9EC0928DF8B15. 

88 Aksoy, M. (1989). Hematotoxicity and carcinogenicity of benzene. Environ. Health Perspect. 82: 193-

197. 

89 Goldstein, B.D. (1988). Benzene toxicity. Occupational medicine. State of the Art Reviews. 3: 541-

554.
Page 53 of 529

data, is the depression of the absolute lymphocyte count in blood.90,91 EPA’s inhalation 

reference concentration (RfC) for benzene is 30 μg/m3. The RfC is based on suppressed 

absolute lymphocyte counts seen in humans under occupational exposure conditions. In 

addition, recent work, including studies sponsored by the Health Effects Institute, 

provides evidence that biochemical responses are occurring at lower levels of benzene 

exposure than previously known.92,93,94,95 EPA’s IRIS program has not yet evaluated 

these new data. EPA does not currently have an acute reference concentration for 

benzene. The Agency for Toxic Substances and Disease Registry (ATSDR) Minimal 

Risk Level (MRL) for acute exposure to benzene is 29 μg/m3for 1-14 days exposure.96,97

ii. Formaldehyde 

In 1991, EPA concluded that formaldehyde is a carcinogen based on nasal tumors 

in animal bioassays.98 An Inhalation Unit Risk for cancer and a Reference Dose for oral 

noncancer effects were developed by the Agency and posted on the IRIS database. Since 

that time, the National Toxicology Program (NTP) and International Agency for 

Research on Cancer (IARC) have concluded that formaldehyde is a known human 

carcinogen.99,100,101

 

90 Rothman, N., G.L. Li, M. Dosemeci, W.E. Bechtold, G.E. Marti, Y.Z. Wang, M. Linet, L.Q. Xi, W. Lu, 

M.T. Smith, N. Titenko-Holland, L.P. Zhang, W. Blot, S.N. Yin, and R.B. Hayes. (1996). Hematotoxicity 

among Chinese workers heavily exposed to benzene. Am. J. Ind. Med. 29: 236-246. 

91 U.S. EPA. (2002). Toxicological Review of Benzene (Noncancer Effects). Environmental Protection 

Agency, Integrated Risk Information System (IRIS), Research and Development, National Center for 

Environmental Assessment, Washington DC. This material is available electronically at 

http://www.epa.gov/iris/subst/0276.htm. 

92 Qu, O.; Shore, R.; Li, G.; Jin, X.; Chen, C.L.; Cohen, B.; Melikian, A.; Eastmond, D.; Rappaport, S.; Li, 

H.; Rupa, D.; Suramaya, R.; Songnian, W.; Huifant, Y.; Meng, M.; Winnik, M.; Kwok, E.; Li, Y.; Mu, 

R.; Xu, B.; Zhang, X.; Li, K. (2003). HEI Report 115, Validation & Evaluation of Biomarkers in Workers 

Exposed to Benzene in China.

93 Qu, Q., R. Shore, G. Li, X. Jin, L.C. Chen, B. Cohen, et al. (2002). Hematological changes among 

Chinese workers with a broad range of benzene exposures. Am. J. Industr. Med. 42: 275-285. 

94 Lan, Qing, Zhang, L., Li, G., Vermeulen, R., et al. (2004). Hematotoxically in Workers Exposed to Low

Levels of Benzene. Science 306: 1774-1776.

95 Turtletaub, K.W. and Mani, C. (2003). Benzene metabolism in rodents at doses relevant to human 

exposure from Urban Air. Research Reports Health Effect Inst. Report No.113. 

96 U.S. Agency for Toxic Substances and Disease Registry (ATSDR). (2007). Toxicological profile for 

benzene. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. 

http://www.atsdr.cdc.gov/ToxProfiles/tp3.pdf.

97 A minimal risk level (MRL) is defined as an estimate of the daily human exposure to a hazardous 

substance that is likely to be without appreciable risk of adverse noncancer health effects over a specified 

duration of exposure.

98 EPA. Integrated Risk Information System. Formaldehyde (CASRN 50-00-0) 

http://www.epa.gov/iris/subst/0419/htm

99 National Toxicology Program, U.S. Department of Health and Human Services (HHS), 12th Report on 

Carcinogens, June 10, 2011

100 IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 88 (2006): 

Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol
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The conclusions by IARC and NTP reflect the results of epidemiologic research 

published since 1991 in combination with previous animal, human and mechanistic 

evidence. Research conducted by the National Cancer Institute reported an increased risk 

of nasopharyngeal cancer and specific lymphohematopoietic malignancies among 

workers exposed to formaldehyde.102,103,104 A National Institute of Occupational Safety 

and Health study of garment workers also reported increased risk of death due to 

leukemia among workers exposed to formaldehyde.105 Extended follow-up of a cohort of 

British chemical workers did not report evidence of an increase in nasopharyngeal or 

lymphohematopoietic cancers, but a continuing statistically significant excess in lung 

cancers was reported.106 Finally, a study of embalmers reported formaldehyde exposures 

to be associated with an increased risk of myeloid leukemia but not brain cancer.107

Health effects of formaldehyde in addition to cancer were reviewed by the 

Agency for Toxics Substances and Disease Registry in 1999108 and supplemented in 

2010,109 and by the World Health Organization.110 These organizations reviewed the 

literature concerning effects on the eyes and respiratory system, the primary point of 

contact for inhaled formaldehyde, including sensory irritation of eyes and respiratory

tract, pulmonary function, nasal histopathology, and immune system effects. In addition, 

research on reproductive and developmental effects and neurological effects were 

discussed.

 

101 IARC Mongraphs on the Evaluation of Carcinogenic Risks to Humans Volume 100F (2012): 

Formaldehyde

102 Hauptmann, M..; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; Blair, A. 2003. Mortality from 

lymphohematopoetic malignancies among workers in formaldehyde industries. Journal of the National 

Cancer Institute 95: 1615-1623. 

103 Hauptmann, M..; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; Blair, A. 2004. Mortality from solid 

cancers among workers in formaldehyde industries. American Journal of Epidemiology 159: 1117-1130. 

104 Beane Freeman, L. E.; Blair, A.; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; Hoover, R. N.; Hauptmann, 

M. 2009. Mortality from lymphohematopoietic malignancies among workers in formaldehyde industries: 

The National Cancer Institute cohort. J. National Cancer Inst. 101: 751-761. 

105 Pinkerton, L. E. 2004. Mortality among a cohort of garment workers exposed to formaldehyde: an 

update. Occup. Environ. Med. 61: 193-200.

106 Coggon, D, EC Harris, J Poole, KT Palmer. 2003. Extended follow-up of a cohort of British chemical 

workers exposed to formaldehyde. J National Cancer Inst. 95:1608-1615.

107 Hauptmann, M,; Stewart P. A.; Lubin J. H.; Beane Freeman, L. E.; Hornung, R. W.; Herrick, R. F.; 

Hoover, R. N.; Fraumeni, J. F.; Hayes, R. B. 2009. Mortality from lymphohematopoietic malignancies and 

brain cancer among embalmers exposed to formaldehyde. Journal of the National Cancer Institute 

101:1696-1708.

108 ATSDR. 1999. Toxicological Profile for Formaldehyde, U.S. Department of Health and Human Services 

(HHS), July 1999.

109 ATSDR. 2010. Addendum to theToxicological Profile for Formaldehyde. U.S. Department of Health 

and Human Services (HHS), October 2010.

110 IPCS. 2002. Concise International Chemical Assessment Document 40. Formaldehyde. World Health 

Organization.
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EPA released a draft Toxicological Review of Formaldehyde – Inhalation 

Assessment through the IRIS program for peer review by the National Research Council 

(NRC) and public comment in June 2010.111 The draft assessment reviewed more recent 

research from animal and human studies on cancer and other health effects. The NRC 

released their review report in April 2011.112 The EPA is currently revising the draft 

assessment in response to this review.

iii.Acetaldehyde 

Acetaldehyde is classified in EPA’s IRIS database as a probable human 

carcinogen, based on nasal tumors in rats, and is considered toxic by the inhalation, oral, 

and intravenous routes.113 The URE in IRIS for acetaldehyde is 2.2 × 10-6per μg/m3.

114

 

Acetaldehyde is reasonably anticipated to be a human carcinogen by the U.S. DHHS in 

the 12th Report on Carcinogens and is classified as possibly carcinogenic to humans 

(Group 2B) by the IARC.115,116 EPA is currently conducting a reassessment of cancer 

risk from inhalation exposure to acetaldehyde.

The primary noncancer effects of exposure to acetaldehyde vapors include 

irritation of the eyes, skin, and respiratory tract.117 In short-term (4 week) rat studies, 

degeneration of olfactory epithelium was observed at various concentration levels of 

acetaldehyde exposure.118,119 Data from these studies were used by EPA to develop an 

inhalation reference concentration of 9 μg/m3. Some asthmatics have been shown to be a 

 

111 EPA (U.S. Environmental Protection Agency). 2010. Toxicological Review of Formaldehyde (CAS No. 

50-00-0) – Inhalation Assessment: In Support of Summary Information on the Integrated Risk Information 

System (IRIS). External Review Draft. EPA/635/R-10/002A. U.S. Environmental Protection Agency, 

Washington DC [online]. Available: http://cfpub.epa.gov/ncea/irs_drats/recordisplay.cfm?deid=223614

112 NRC (National Research Council). 2011. Review of the Environmental Protection Agency’s Draft IRIS 

Assessment of Formaldehyde. Washington DC: National Academies Press. 

http://books.nap.edu/openbook.php?record_id=13142

113 U.S. EPA (1991). Integrated Risk Information System File of Acetaldehyde. Research and 

Development, National Center for Environmental Assessment, Washington, DC. This material is available 

electronically at http://www.epa.gov/iris/subst/0290.htm. 

114 U.S. EPA (1991). Integrated Risk Information System File of Acetaldehyde. This material is available 

electronically at http://www.epa.gov/iris/subst/0290.htm. 

115 NTP. (2011). Report on Carcinogens, Twelfth Edition. Research Triangle Park, NC: U.S. Department of 

Health and Human Services, Public Health Service, National Toxicology Program. 499 pp.

116 International Agency for Research on Cancer (IARC). (1999). Re-evaluation of some organic chemicals, 

hydrazine, and hydrogen peroxide. IARC Monographs on the Evaluation of Carcinogenic Risk of 

Chemical to Humans, Vol 71. Lyon, France.

117 U.S. EPA (1991). Integrated Risk Information System File of Acetaldehyde. This material is available 

electronically at http://www.epa.gov/iris/subst/0290.htm. 

118 U.S. EPA. (2003). Integrated Risk Information System File of Acrolein. Research and Development, 

National Center for Environmental Assessment, Washington, DC. This material is available electronically 

at http://www.epa.gov/iris/subst/0364.htm. 

119 Appleman, L.M., R.A. Woutersen, and V.J. Feron. (1982). Inhalation toxicity of acetaldehyde in rats. I. 

Acute and subacute studies. Toxicology. 23: 293-297. 
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sensitive subpopulation to decrements in functional expiratory volume (FEV1 test) and 

bronchoconstriction upon acetaldehyde inhalation.120 The agency is currently conducting 

a reassessment of the health hazards from inhalation exposure to acetaldehyde. 

iv. Acrolein

EPA most recently evaluated the toxicological and health effects literature related 

to acrolein in 2003 and concluded that the human carcinogenic potential of acrolein could 

not be determined because the available data were inadequate. No information was 

available on the carcinogenic effects of acrolein in humans and the animal data provided 

inadequate evidence of carcinogenicity.

121

 The IARC determined in 1995 that acrolein 

was not classifiable as to its carcinogenicity in humans.122 

Lesions to the lungs and upper respiratory tract of rats, rabbits, and hamsters have 

been observed after subchronic exposure to acrolein.123 The Agency has developed an 

RfC for acrolein of 0.02 μg/m

3 and an RfD of 0.5 μg/kg-day.124

 EPA is considering 

updating the acrolein assessment with data that have become available since the 2003 

assessment was completed.

Acrolein is extremely acrid and irritating to humans when inhaled, with acute 

exposure resulting in upper respiratory tract irritation, mucus hypersecretion and 

congestion. The intense irritancy of this carbonyl has been demonstrated during 

controlled tests in human subjects, who suffer intolerable eye and nasal mucosal sensory

reactions within minutes of exposure.125 These data and additional studies regarding 

acute effects of human exposure to acrolein are summarized in EPA’s 2003 IRIS Human 

 

120 Myou, S.; Fujimura, M.; Nishi K.; Ohka, T.; and Matsuda, T. (1993) Aerosolized acetaldehyde induces 

histamine-mediated bronchoconstriction in asthmatics. Am. Rev. Respir.Dis.148(4 Pt 1): 940-943. 

121 U.S. EPA. (2003). Integrated Risk Information System File of Acrolein. Research and Development, 

National Center for Environmental Assessment, Washington, DC. This material is available at 

http://www.epa.gov/iris/subst/0364.htm. 

122 International Agency for Research on Cancer (IARC). (1995). Monographs on the evaluation of 

carcinogenic risk of chemicals to humans, Volume 63. Dry cleaning, some chlorinated solvents and other 

industrial chemicals, World Health Organization, Lyon, France. 

123 U.S. EPA. (2003). Integrated Risk Information System File of Acrolein. Office of Research and 

Development, National Center for Environmental Assessment, Washington, DC. This material is available 

at http://www.epa.gov/iris/subst/0364.htm. 

124 U.S. EPA. (2003). Integrated Risk Information System File of Acrolein. Office of Research and 

Development, National Center for Environmental Assessment, Washington, DC. This material is available 

at http://www.epa.gov/iris/subst/0364.htm. 

125 U.S. EPA. (2003) Toxicological review of acrolein in support of summary information on Integrated 

Risk Information System (IRIS) National Center for Environmental Assessment, Washington, DC. 

EPA/635/R-03/003. p. 10. Available online at: http://www.epa.gov/ncea/iris/toxreviews/0364tr.pdf. 
Page 57 of 529

Health Assessment for acrolein.126 Studies in humans indicate that levels as low as 0.09 

ppm (0.21 mg/m3) for five minutes may elicit subjective complaints of eye irritation with 

increasing concentrations leading to more extensive eye, nose and respiratory symptoms. 

Acute exposures in animal studies report bronchial hyper-responsiveness. Based on 

animal data (more pronounced respiratory irritancy in mice with allergic airway disease 

in comparison to non-diseased mice127) and demonstration of similar effects in humans 

(e.g., reduction in respiratory rate), individuals with compromised respiratory function 

(e.g., emphysema, asthma) are expected to be at increased risk of developing adverse 

responses to strong respiratory irritants such as acrolein. EPA does not currently have an 

acute reference concentration for acrolein. The available health effect reference values 

for acrolein have been summarized by EPA and include an ATSDR MRL for acute 

exposure to acrolein of 7 μg/m3for 1-14 days exposure; and Reference Exposure Level 

(REL) values from the California Office of Environmental Health Hazard Assessment 

(OEHHA) for one-hour and 8-hour exposures of 2.5 μg/m3and 0.7 μg/m3, 

respectively.

128

v. 1,3-Butadiene

EPA has characterized 1,3-butadiene as carcinogenic to humans by

inhalation.129,130 The IARC has determined that 1,3-butadiene is a human carcinogen and 

the U.S. DHHS has characterized 1,3-butadiene as a known human carcinogen.131,132,133 

There are numerous studies consistently demonstrating that 1,3-butadiene is metabolized 

into genotoxic metabolites by experimental animals and humans. The specific 

mechanisms of 1,3-butadiene-induced carcinogenesis are unknown; however, the 

 

126 U.S. EPA. (2003) Toxicological review of acrolein in support of summary information on Integrated 

Risk Information System (IRIS) National Center for Environmental Assessment, Washington, DC. 

EPA/635/R-03/003. Available online at: http://www.epa.gov/ncea/iris/toxreviews/0364tr.pdf. 

127 Morris JB, Symanowicz PT, Olsen JE, et al. (2003). Immediate sensory nerve-mediated respiratory 

responses to irritants in healthy and allergic airway-diseased mice. J Appl Physiol 94(4):1563-1571. 

128 U.S. EPA. (2009). Graphical Arrays of Chemical-Specific Health Effect Reference Values for Inhalation 

Exposures (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/061, 

2009. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003 

129 U.S. EPA. (2002). Health Assessment of 1,3-Butadiene. Office of Research and Development, National 

Center for Environmental Assessment, Washington Office, Washington, DC. Report No. EPA600-P-98-

001F. This document is available electronically at http://www.epa.gov/iris/supdocs/buta-sup.pdf. 

130 U.S. EPA. (2002). “Full IRIS Summary for 1,3-butadiene (CASRN 106-99-0)” Environmental 

Protection Agency, Integrated Risk Information System (IRIS), Research and Development, National 

Center for Environmental Assessment, Washington, DC http://www.epa.gov/iris/subst/0139.htm. 

131 International Agency for Research on Cancer (IARC). (1999). Monographs on the evaluation of 

carcinogenic risk of chemicals to humans, Volume 71, Re-evaluation of some organic chemicals, hydrazine 

and hydrogen peroxide and Volume 97 (in preparation), World Health Organization, Lyon, France. 

132 International Agency for Research on Cancer (IARC). (2008). Monographs on the evaluation of 

carcinogenic risk of chemicals to humans, 1,3-Butadiene, Ethylene Oxide and Vinyl Halides (Vinyl 

Fluoride, Vinyl Chloride and Vinyl Bromide) Volume 97, World Health Organization, Lyon, France. 

133 NTP. (2011). Report on Carcinogens, Twelfth Edition. Research Triangle Park, NC: U.S. Department of 

Health and Human Services, Public Health Service, National Toxicology Program. 499 pp.
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scientific evidence strongly suggests that the carcinogenic effects are mediated by

genotoxic metabolites. Animal data suggest that females may be more sensitive than 

males for cancer effects associated with 1,3-butadiene exposure; there are insufficient 

data in humans from which to draw conclusions about sensitive subpopulations. The 

URE for 1,3-butadiene is 3 × 10-5per μg/m3.

134 1,3-butadiene also causes a variety of 

reproductive and developmental effects in mice; no human data on these effects are 

available. The most sensitive effect was ovarian atrophy observed in a lifetime bioassay

of female mice.135 Based on this critical effect and the benchmark concentration 

methodology, an RfC for chronic health effects was calculated at 0.9 ppb (approximately

2 μg/m3).

vi. Ethanol

EPA is planning to develop an assessment of the health effects of exposure to 

ethanol, a compound which is not currently listed on EPA’s IRIS database. Extensive 

health effects data are available for ingestion of ethanol, while data on inhalation 

exposure effects are sparse. In developing the assessment, EPA is evaluating 

pharmacokinetic models as a means of extrapolating across species (animal to human) 

and across exposure routes (oral to inhalation) to better characterize the health hazards 

and dose-response relationships for low levels of ethanol exposure in the environment.

vii. Polycyclic Organic Matter

The term polycyclic organic matter (POM) defines a broad class of compounds 

that includes the polycyclic aromatic hydrocarbon compounds (PAHs). One of these 

compounds, naphthalene, is discussed separately below. POM compounds are formed 

primarily from combustion and are present in the atmosphere in gas and particulate form. 

Cancer is the major concern from exposure to POM. Epidemiologic studies have 

reported an increase in lung cancer in humans exposed to diesel exhaust, coke oven 

emissions, roofing tar emissions, and cigarette smoke; all of these mixtures contain POM 

compounds.136,137 Animal studies have reported respiratory tract tumors from inhalation 

exposure to benzo[a]pyrene and alimentary tract and liver tumors from oral exposure to 

 

134 U.S. EPA. (2002). “Full IRIS Summary for 1,3-butadiene (CASRN 106-99-0)” Environmental 

Protection Agency, Integrated Risk Information System (IRIS), Research and Development, National 

Center for Environmental Assessment, Washington, DC http://www.epa.gov/iris/subst/0139.htm. 

135 Bevan, C.; Stadler, J.C.; Elliot, G.S.; et al. (1996). Subchronic toxicity of 4-vinylcyclohexene in rats and 

mice by inhalation. Fundam. Appl. Toxicol. 32:1-10.

136 Agency for Toxic Substances and Disease Registry (ATSDR). (1995). Toxicological profile for 

Polycyclic Aromatic Hydrocarbons (PAHs). Atlanta, GA: U.S. Department of Health and Human Services, 

Public Health Service. Available electronically at 

http://www.atsdr.cdc.gov/ToxProfiles/TP.asp?id=122&tid=25. 

137 U.S. EPA (2002). Health Assessment Document for Diesel Engine Exhaust. EPA/600/8-90/057F Office 

of Research and Development, Washington DC. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060. 
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benzo[a]pyrene.138 In 1997 EPA classified seven PAHs (benzo[a]pyrene, 

benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, 

dibenz[a,h]anthracene, and indeno[1,2,3-cd]pyrene) as Group B2, probable human 

carcinogens.139 Since that time, studies have found that maternal exposures to PAHs in a 

population of pregnant women were associated with several adverse birth outcomes, 

including low birth weight and reduced length at birth, as well as impaired cognitive 

development in preschool children (3 years of age).140,141 These and similar studies are 

being evaluated as a part of the ongoing IRIS assessment of health effects associated with 

exposure to benzo[a]pyrene.

viii. Naphthalene

Naphthalene is found in small quantities in gasoline and diesel fuels. 

Naphthalene emissions have been measured in larger quantities in both gasoline and 

diesel exhaust compared with evaporative emissions from mobile sources, indicating it is 

primarily a product of combustion. Acute (short-term) exposure of humans to 

naphthalene by inhalation, ingestion, or dermal contact is associated with hemolytic 

anemia and damage to the liver and the nervous system.142 Chronic (long term) exposure 

of workers and rodents to naphthalene has been reported to cause cataracts and retinal 

damage.143 EPA released an external review draft of a reassessment of the inhalation 

carcinogenicity of naphthalene based on a number of recent animal carcinogenicity

studies.144 The draft reassessment completed external peer review.145 Based on external 

 

138 International Agency for Research on Cancer (IARC). (2012). Monographs on the Evaluation of the 

Carcinogenic Risk of Chemicals for Humans, Chemical Agents and Related Occupations. Vol. 100F. 

Lyon, France.

139 U.S. EPA (1997). Integrated Risk Information System File of indeno(1,2,3-cd)pyrene. Research and 

Development, National Center for Environmental Assessment, Washington, DC. This material is available 

electronically at http://www.epa.gov/ncea/iris/subst/0457.htm. 

140 Perera, F.P.; Rauh, V.; Tsai, W-Y.; et al. (2002). Effect of transplacental exposure to environmental 

pollutants on birth outcomes in a multiethnic population. Environ Health Perspect. 111: 201-205. 

141 Perera, F.P.; Rauh, V.; Whyatt, R.M.; Tsai, W.Y.; Tang, D.; Diaz, D.; Hoepner, L.; Barr, D.; Tu, Y.H.; 

Camann, D.; Kinney, P. (2006). Effect of prenatal exposure to airborne polycyclic aromatic hydrocarbons 

on neurodevelopment in the first 3 years of life among inner-city children. Environ Health Perspect 114: 

1287-1292. 

142 U. S. EPA. 1998. Toxicological Review of Naphthalene (Reassessment of the Inhalation Cancer Risk), 

Environmental Protection Agency, Integrated Risk Information System, Research and Development, 

National Center for Environmental Assessment, Washington, DC. This material is available electronically 

at http://www.epa.gov/iris/subst/0436.htm.

143 U. S. EPA. 1998. Toxicological Review of Naphthalene (Reassessment of the Inhalation Cancer Risk), 

Environmental Protection Agency, Integrated Risk Information System, Research and Development, 

National Center for Environmental Assessment, Washington, DC. This material is available electronically 

at http://www.epa.gov/iris/subst/0436.htm.

144 U. S. EPA. (1998). Toxicological Review of Naphthalene (Reassessment of the Inhalation Cancer 

Risk), Environmental Protection Agency, Integrated Risk Information System, Research and Development, 

National Center for Environmental Assessment, Washington, DC. This material is available electronically 

at http://www.epa.gov/iris/subst/0436.htm. 
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peer review comments received, a revised draft assessment that considers all routes of 

exposure, as well as cancer and noncancer effects, is under development. The external 

review draft does not represent official agency opinion and was released solely for the 

purposes of external peer review and public comment. The National Toxicology

Program listed naphthalene as "reasonably anticipated to be a human carcinogen" in 2004 

on the basis of bioassays reporting clear evidence of carcinogenicity in rats and some 

evidence of carcinogenicity in mice.146 California EPA has released a new risk 

assessment for naphthalene, and the IARC has reevaluated naphthalene and re-classified 

it as Group 2B: possibly carcinogenic to humans.147 

Naphthalene also causes a number of chronic non-cancer effects in animals, 

including abnormal cell changes and growth in respiratory and nasal tissues.148 The 

current EPA IRIS assessment includes noncancer data on hyperplasia and metaplasia in 

nasal tissue that form the basis of the inhalation RfC of 3 μg/m3.

149

 The ATSDR MRL

for acute exposure to naphthalene is 0.6 mg/kg/day.

ix. Other Air Toxics

In addition to the compounds described above, other compounds in gaseous 

hydrocarbon and PM emissions from motor vehicles will be affected by this action. 

Mobile source air toxic compounds that will potentially be impacted include 

ethylbenzene, propionaldehyde, toluene, and xylene. Information regarding the health 

effects of these compounds can be found in EPA’s IRIS database.150

b. Current Concentrations of Air Toxics 

The most recent available data indicate that the majority of Americans continue to 

be exposed to ambient concentrations of air toxics at levels which have the potential to 

cause adverse health effects.151 The levels of air toxics to which people are exposed vary

 

145 Oak Ridge Institute for Science and Education. (2004). External Peer Review for the IRIS 

Reassessment of the Inhalation Carcinogenicity of Naphthalene. August 2004. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=84403. 

146 NTP. (2011). Report on Carcinogens, Twelfth Edition. Research Triangle Park, NC: U.S. Department of 

Health and Human Services, Public Health Service, National Toxicology Program. 499 pp.

147 International Agency for Research on Cancer (IARC). (2002). Monographs on the Evaluation of the 

Carcinogenic Risk of Chemicals for Humans. Vol. 82. Lyon, France. 

148 U. S. EPA. (1998). Toxicological Review of Naphthalene, Environmental Protection Agency, Integrated 

Risk Information System, Research and Development, National Center for Environmental Assessment, 

Washington, DC. This material is available electronically at http://www.epa.gov/iris/subst/0436.htm 

149 U.S. EPA. (1998). Toxicological Review of Naphthalene. Environmental Protection Agency, 

Integrated Risk Information System (IRIS), Research and Development, National Center for Environmental 

Assessment, Washington, DC http://www.epa.gov/iris/subst/0436.htm. 

150 U.S. EPA Integrated Risk Information System (IRIS) database is available at: www.epa.gov/iris 

151 U.S. EPA. (2011) Summary of Results for the 2005 National-Scale Assessment. 

www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
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depending on where people live and work and the kinds of activities in which they

engage, as discussed in detail in U.S. EPA’s most recent Mobile Source Air Toxics 

Rule.152 According to the National Air Toxic Assessment (NATA) for 2005,153 mobile 

sources were responsible for 43 percent of outdoor toxic emissions and over 50 percent of 

the cancer risk and noncancer hazard associated with primary emissions. Mobile sources 

are also large contributors to precursor emissions which react to form secondary

concentrations of air toxics. Formaldehyde is the largest contributor to cancer risk of all 

80 pollutants quantitatively assessed in the 2005 NATA. Mobile sources were 

responsible for over 40 percent of primary emissions of this pollutant in 2005, and are 

major contributors to formaldehyde precursor emissions. Benzene is also a large 

contributor to cancer risk, and mobile sources account for over 70 percent of ambient 

exposure. Over the years, EPA has implemented a number of mobile source and fuel 

controls which have resulted in VOC reductions, which also reduced formaldehyde, 

benzene and other air toxic emissions.

6. Near-Roadway Pollution

Locations in close proximity to major roadways generally have elevated 

concentrations of many air pollutants emitted from motor vehicles. Hundreds of such 

studies have been published in peer-reviewed journals, concluding that concentrations of 

CO, NO, NO2, benzene, aldehydes, particulate matter, black carbon, and many other 

compounds are elevated in ambient air within approximately 300-600 meters (about 

1,000-2,000 feet) of major roadways. Highest concentrations of most pollutants emitted 

directly by motor vehicles are found at locations within 50 meters (about 165 feet) of the 

edge of a roadway’s traffic lanes.

A recent large-scale review of air quality measurements in vicinity of major 

roadways between 1978 and 2008 concluded that the pollutants with the steepest 

concentration gradients in vicinities of roadways were CO, ultrafine particles, metals, 

elemental carbon (EC), NO, NOX, and several VOCs.154 These pollutants showed a large 

reduction in concentrations within 100 meters downwind of the roadway. Pollutants that 

showed more gradual reductions with distance from roadways included benzene, NO2, 

PM2.5, and PM10. In the review article, results varied based on the method of statistical 

analysis used to determine the trend.

For pollutants with relatively high background concentrations relative to nearroad concentrations, detecting concentration gradients can be difficult. For example, 

many aldehydes have high background concentrations as a result of photochemical 

 

152 U. S. Environmental Protection Agency (2007). Control of Hazardous Air Pollutants from Mobile 

Sources; Final Rule. 72 FR 8434, February 26, 2007. 

153 U. S. EPA. (2011). 2005 National-Scale Air Toxics Assessment. http://www.epa.gov/ttn/atw/nata2005/. 

154 Karner, A.A.; Eisinger, D.S.; Niemeier, D.A. (2010). Near-roadway air quality: synthesizing the 

findings from real-world data. Environ Sci Technol 44: 5334-5344.
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breakdown of precursors from many different organic compounds. This can make 

detection of gradients around roadways and other primary emission sources difficult. 

However, several studies have measured aldehydes in multiple weather conditions, and 

found higher concentrations of many carbonyls downwind of roadways.155,156 These 

findings suggest a substantial roadway source of these carbonyls.

In the past 15 years, many studies have been published with results reporting that 

populations who live, work, or go to school near high-traffic roadways experience higher 

rates of numerous adverse health effects, compared to populations far away from major 

roads.157 In addition, numerous studies have found adverse health effects associated with 

spending time in traffic, such as commuting or walking along high-traffic 

roadways.158,159,160,161 The health outcomes with the strongest evidence linking them with 

traffic-associated air pollutants are respiratory effects, particularly in asthmatic children, 

and cardiovascular effects.

Numerous reviews of this body of health literature have been published as well. 

In 2010, an expert panel of the Health Effects Institute (HEI) published a review of 

hundreds of exposure, epidemiology, and toxicology studies.162 The panel rated how the 

evidence for each type of health outcome supported a conclusion of a causal association 

with traffic-associated air pollution as either “sufficient,” “suggestive but not sufficient,” 

or “inadequate and insufficient.” The panel categorized evidence of a causal association 

for exacerbation of childhood asthma as “sufficient.” The panel categorized evidence of 

a causal association for new onset asthma as between “sufficient” and as “suggestive but 

not sufficient.” “Suggestive of a causal association” was how the panel categorized 

 

155 Liu, W.; Zhang, J.; Kwon, J.l; et l. (2006). Concentrations and source characteristics of airborne 

carbonyl compounds measured outside urban residences. J Air Waste Manage Assoc 56: 1196-1204.

156 Cahill, T.M.; Charles, M.J.; Seaman, V.Y. (2010). Development and application of a sensitive method to 

determine concentrations of acrolein and other carbonyls in ambient air. Health Effects Institute Research 

Report 149.Available at http://dx.doi.org

157 In the widely-used PubMed database of health publications, between January 1, 1990 and August 18, 

2011, 605 publications contained the keywords “traffic, pollution, epidemiology,” with approximately half 

the studies published after 2007. 

158 Laden, F.; Hart, J.E.; Smith, T.J.; Davis, M.E.; Garshick, E. (2007) Cause-specific mortality in the 

unionized U.S. trucking industry. Environmental Health Perspect 115:1192-1196.

159 Peters, A.; von Klot, S.; Heier, M.; Trentinaglia, I.; Hörmann, A.; Wichmann, H.E.; Löwel, H. (2004) 

Exposure to traffic and the onset of myocardial infarction. New England J Med 351: 1721-1730.

160 Zanobetti, A.; Stone, P.H.; Spelzer, F.E.; Schwartz, J.D.; Coull, B.A.; Suh, H.H.; Nearling, B.D.; 

Mittleman, M.A.; Verrier, R.L.; Gold, D.R. (2009) T-wave alternans, air pollution and traffic in high-risk 

subjects. Am J Cardiol 104: 665-670.

161 Dubowsky Adar, S.; Adamkiewicz, G.; Gold, D.R.; Schwartz, J.; Coull, B.A.; Suh, H. (2007) Ambient 

and microenvironmental particles and exhaled nitric oxide before and after a group bus trip. Environ 

Health Perspect 115: 507-512.

162 Health Effects Institute Panel on the Health Effects of Traffic-Related Air Pollution. (2010). Trafficrelated air pollution: a critical review of the literature on emissions, exposure, and health effects. HEI 

Special Report 17. Available at http://www.healtheffects.org
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evidence linking traffic-associated air pollutants with exacerbation of adult respiratory

symptoms and lung function decrement. It categorized as “inadequate and insufficient” 

evidence of a causal relationship between traffic-related air pollution and health care 

utilization for respiratory problems, new onset adult asthma, chronic obstructive 

pulmonary disease (COPD), nonasthmatic respiratory allergy, and cancer in adults and 

children. Other literature reviews have been published with conclusions similar to the 

HEI panel’s.163,164,165 Health outcomes with few publications suggest the possibility of 

other effects still lacking sufficient evidence to draw definitive conclusions. Among 

these outcomes with a small number of positive studies are neurological impacts (e.g., 

autism and reduced cognitive function) and reproductive outcomes (e.g., preterm birth, 

low birth weight).166,167,168,169

In addition to health outcomes, particularly cardiopulmonary effects, conclusions 

of numerous studies suggest mechanisms by which traffic-related air pollution affects 

health. Numerous studies indicate that near-roadway exposures may increase systemic 

inflammation, affecting organ systems, including blood vessels and lungs.170,171,172,173 

Long-term exposures in near-road environments have been associated with inflammationassociated conditions, such as atherosclerosis and asthma.174,175,176

 

 

163 Boothe, V.L.; Shendell, D.G. (2008). Potential health effects associated with residential proximity to 

freeways and primay roads: review of scientific literature, 1999-2006. J Environ Health 70: 33-41.

164 Salam, M.T.; Islam, T.; Gilliland, F.D. (2008). Recent evidence for adverse effects of residential 

proximity to traffic sources on asthma. Curr Opin Pulm Med 14: 3-8.

165 Raaschou-Nielsen, O.; Reynolds, P. (2006). Air pollution and childhood cancer: a review of the 

epidemiological literature. Int J Cancer 118: 2920-9.

166 Volk, H.E.; Hertz-Picciotto, I.; Delwiche, L.; et al. (2011). Residential proximity to freeways and autism 

in the CHARGE study. Environ Health Perspect 119: 873-877.

167 Franco-Suglia, S.; Gryparis, A.; Wright, R.O.; et al. (2007). Association of black carbon with cognition 

among children in a prospective birth cohort study. Am J Epidemiol. doi: 10.1093/aje/kwm308. [Online at 

http://dx.doi.org]

168 Power, M.C.; Weisskopf, M.G.; Alexeef, S.E.; et al. (2011). Traffic-related air pollution and cognitive 

function in a cohort of older men. Environ Health Perspect 2011: 682-687.

169 Wu, J.; Wilhelm, M.; Chung, J.; et al. (2011). Comparing exposure assessment methods for trafficrelated air pollution in and adverse pregnancy outcome study. Environ Res 111: 685-6692.

170 Riediker, M. (2007). Cardiovascular effects of fine particulate matter components in highway patrol 

officers. Inhal Toxicol 19: 99-105. doi: 10.1080/08958370701495238 Available at http://dx.doi.org

171 Alexeef, S.E.; Coull, B.A.; Gryparis, A.; et al. (2011). Medium-term exposure to traffic-related air 

pollution and markers of inflammation and endothelial function. Environ Health Perspect 119: 481-486. 

doi:10.1289/ehp.1002560 Available at http://dx.doi.org

172 Eckel. S.P.; Berhane, K.; Salam, M.T.; et al. (2011). Traffic-related pollution exposure and exhaled 

nitric oxide in the Children’s Health Study. Environ Health Perspect (IN PRESS). 

doi:10.1289/ehp.1103516. Available at http://dx.doi.org

173 Zhang, J.; McCreanor, J.E.; Cullinan, P.; et al. (2009). Health effects of real-world exposure diesel 

exhaust in persons with asthma. Res Rep Health Effects Inst 138. [Online at http://www.healtheffects.org]

174 Adar, S.D.; Klein, R.; Klein, E.K.; et al. (2010). Air pollution and the microvasculatory: a crosssectional assessment of in vivo retinal images in the population-based Multi-Ethnic Study of 
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Several studies suggest that some factors may increase susceptibility to the effects 

of traffic-associated air pollution. Several studies have found stronger respiratory

associations in children experiencing chronic social stress, such as in violent 

neighborhoods or in homes with high family stress.177,178,179 

The risks associated with residence, workplace, or schools near major roads are of 

potentially high public health significance due to the large population in such locations. 

According to the 2009 American Housing Survey, over 22 million homes (17.0 percent 

of all U.S. housing units) were located within 300 feet of an airport, railroad, or highway

with four or more lanes. This corresponds to a population of more than 50 million U.S. 

residents in close proximity to high-traffic roadways or other transportation sources. 

Based on 2010 Census data, a 2013 publication estimated that 19 percent of the U.S. 

population (over 59 million people) lived within 500 meters of roads with at least 25,000 

annual average daily traffic (AADT), while about 3.2 percent of the population lived 

within 100 meters (about 300 feet) of such roads.180 Another 2013 study estimated that 

3.7 percent of the U.S. population (about 11.3 million people) lived within 150 meters 

(about 500 feet) of interstate highways, or other freeways and expressways.181 As 

discussed in Section III, on average, populations near major roads have higher fractions 

of minority residents and lower socioeconomic status. Furthermore, on average, 

Americans spend more than an hour traveling each day, bringing nearly all residents into 

a high-exposure microenvironment for part of the day.

In light of these concerns, EPA has required and is working with states to ensure 

that air quality monitors be placed near high-traffic roadways for determining NAAQS 

compliance for CO, NO2, and PM2.5 (in addition to those existing monitors located in 

neighborhoods and other locations farther away from pollution sources). Near-roadway

monitors for NO2 begin operation between 2014 and 2017 in Core Based Statistical Areas 

(CBSAs) with population of at least 500,000. Monitors for CO and PM2.5 begin 

 

Atherosclerosis. PLoS Med 7(11): E1000372. doi:10.1371/journal.pmed.1000372. Available at 

http://dx.doi.org

175 Kan, H.; Heiss, G.; Rose, K.M.; et al. (2008). Proxpective analysis of traffic exposure as a risk factor for 

incident coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) study. Environ Health 

Perspect 116: 1463-1468. doi:10.1289/ehp.11290. Available at http://dx.doi.org

176 McConnell, R.; Islam, T.; Shankardass, K.; et al. (2010). Childhood incident asthma and traffic-related 

air pollution at home and school. Environ Health Perspect 1021-1026.

177 Islam, T.; Urban, R.; Gauderman, W.J.; et al. (2011). Parental stress increases the detrimental effect of 

traffic exposure on children’s lung function. Am J Respir Crit Care Med (In press) 

178 Clougherty, J.E.; Levy, J.I.; Kubzansky, L.D.; et al. (2007). Synergistic effects of traffic-related air 

pollution and exposure to violence on urban asthma etiology. Environ Health Perspect 115: 1140-1146.

179 Chen, E.; Schrier, H.M.; Strunk, R.C.; et al. (2008). Chronic traffic-related air pollution and stress 

interact to predict biologic and clinical outcomes in asthma. Environ Health Perspect 116: 970-5.

180 Rowangould, G.M. (2013) A census of the US near-roadway population: public health and 

environmental justice considerations. Transportation Research Part D 25: 59-67.

181 Boehmer, T.K.; Foster, S.L.; Henry, J.R.; Woghiren-Akinnifesi, E.L.; Yip, F.Y. (2013) Residential 

proximity to major highways – United States, 2010. Morbidity and Mortality Weekly Report 62(3);46-50.
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operation between 2015 and 2017. These monitors will further our understanding of 

exposure in these locations.

EPA continues to research near-road air quality, including the types of pollutants 

found in high concentrations near major roads and health problems associated with the 

mixture of pollutants near roads. 

7. Environmental Impacts of Motor Vehicles and Fuels

a. Plant and Ecosystem Effects of Ozone

The welfare effects of ozone can be observed across a variety of scales, i.e. 

subcellular, cellular, leaf, whole plant, population and ecosystem. Ozone effects that 

begin at small spatial scales, such as the leaf of an individual plant, when they occur at 

sufficient magnitudes (or to a sufficient degree) can result in effects being propagated 

along a continuum to larger and larger spatial scales. For example, effects at the 

individual plant level, such as altered rates of leaf gas exchange, growth and reproduction 

can, when widespread, result in broad changes in ecosystems, such as productivity, 

carbon storage, water cycling, nutrient cycling, and community composition.

Ozone can produce both acute and chronic injury in sensitive species depending 

on the concentration level and the duration of the exposure.182 In those sensitive species, 

ozone effects also tend to accumulate over the growing season of the plant, so that even 

low concentrations experienced for a longer duration have the potential to create chronic 

stress on vegetation. Ozone damage to sensitive species includes visible injury to leaves 

and impaired photosynthesis, both of which can lead to reduced plant growth and 

reproduction, resulting in reduced crop yields, forestry production, and use of sensitive 

ornamentals in landscaping. In addition, the impairment of photosynthesis, the process 

by which the plant makes carbohydrates (its source of energy and food), can lead to a 

subsequent reduction in root growth and carbohydrate storage below ground, resulting in 

other, more subtle plant and ecosystems impacts. These latter impacts include increased 

susceptibility of plants to insect attack, disease, harsh weather, interspecies competition 

and overall decreased plant vigor. The adverse effects of ozone on areas with sensitive 

species could potentially lead to species shifts and loss from the affected ecosystems, 

 

182 Only a small percentage of all the plant species growing within the U.S. (over 43,000 species have been 

catalogued in the USDA PLANTS database) have been studied with respect to ozone sensitivity (U.S. EPA. 

Review of the National Ambient Air Quality Standards for Ozone: Policy Assessment of Scientific and 

Technical Information. OAQPS Staff Paper. U.S. Environmental Protection Agency, Washington, DC, 

EPA-452/R-07-007, 2007. p.7-7). Thus, ozone impacts could be occurring in areas where plant species 

sensitive to ozone have not yet been studied or identified. In addition, the concentration at which ozone 

levels overwhelm a plant’s ability to detoxify or compensate for oxidant exposure varies (U.S. EPA. 

Welfare Risk and Exposure Assessment for Ozone. Second External Review Draft. EPA-452/P-14-003a, 

2014. Figure 6-2, p. 6-5). Thus, whether a plant is classified as sensitive or tolerant depends in part on the 

exposure levels being considered.
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resulting in a loss or reduction in associated ecosystem goods and services. Lastly, 

visible ozone injury to leaves can result in a loss of aesthetic value in areas of special 

scenic significance like national parks and wilderness areas. 

The Integrated Science Assessment (ISA) for Ozone presents more detailed 

information on how ozone effects vegetation and ecosystems.183 The ISA concludes that 

ambient concentrations of ozone are associated with a number of adverse welfare effects 

and characterizes the weight of evidence for different effects associated with ozone.184 

The ISA concludes that visible foliar injury effects on vegetation, reduced vegetation 

growth, reduced productivity in terrestrial ecosystems, reduced yield and quality of 

agricultural crops, and alteration of below-ground biogeochemical cycles are causally 

associated with exposure to ozone. It also concludes that reduced carbon sequestration in 

terrestrial ecosystems, alteration of terrestrial ecosystem water cycling, and alteration of 

terrestrial community composition are likely to be causally associated with exposure to 

ozone. 

b. Visibility

Visibility can be defined as the degree to which the atmosphere is transparent to 

visible light.185 Visibility impairment is caused by light scattering and absorption by

suspended particles and gases. Visibility is important because it has direct significance to 

people’s enjoyment of daily activities in all parts of the country. Individuals value good 

visibility for the well-being it provides them directly, where they live and work, and in 

places where they enjoy recreational opportunities. Visibility is also highly valued in 

significant natural areas, such as national parks and wilderness areas, and special 

emphasis is given to protecting visibility in these areas. For more information on 

visibility see the final 2009 PM ISA.186

 

183 U.S. EPA. Integrated Science Assessment of Ozone and Related Photochemical Oxidants (Final 

Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-10/076F, 2013. The ISA is 

available at http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=247492#Download

184 The Ozone ISA evaluates the evidence associated with different ozone related health and welfare

effects, assigning one of five “weight of evidence” determinations: causal relationship, likely to be a causal 

relationship, suggestive of a causal relationship, inadequate to infer a causal relationship, and not likely to 

be a causal relationship. For more information on these levels of evidence, please refer to Table II of the 

ISA. 

185 National Research Council, (1993). Protecting Visibility in National Parks and Wilderness Areas. 

National Academy of Sciences Committee on Haze in National Parks and Wilderness Areas. National 

Academy Press, Washington, DC. This book can be viewed on the National Academy Press Website at 

http://www.nap.edu/books/0309048443/html/

186 U.S. EPA. (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F. 
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EPA is working to address visibility impairment. In 1999, EPA finalized the 

regional haze program to protect the visibility in Mandatory Class I Federal areas.187 

There are 156 national parks, forests and wilderness areas categorized as Mandatory

Class I Federal areas.188 These areas are defined in CAA section 162 as those national 

parks exceeding 6,000 acres, wilderness areas and memorial parks exceeding 5,000 acres, 

and all international parks which were in existence on August 7, 1977. EPA has also 

concluded that PM2.5 causes adverse effects on visibility in other areas that are not 

protected by the Regional Haze Rule, depending on PM2.5 concentrations and other 

factors that control their visibility impact effectiveness such as dry chemical composition 

and relative humidity (i.e., an indicator of the water composition of the particles). EPA 

revised the PM2.5 standards in December 2012 and established a target level of protection 

that is expected to be met through attainment of the existing secondary standards for 

PM2.5. 

i. Current Visibility Levels

As mentioned in Section II.B.2.c, millions of people live in nonattainment areas 

for the PM2.5 NAAQS. These populations, as well as large numbers of individuals who 

travel to these areas, are likely to experience visibility impairment. In addition, while 

visibility trends have improved in mandatory class I federal areas, the most recent data 

show that these areas continue to suffer from visibility impairment. In summary, 

visibility impairment is experienced throughout the U.S., in multi-state regions, urban 

areas, and remote mandatory class I federal areas.

c. Atmospheric Deposition

Wet and dry deposition of ambient particulate matter delivers a complex mixture 

of metals (e.g., mercury, zinc, lead, nickel, aluminum, cadmium), organic compounds 

(e.g., polycyclic organic matter, dioxins, furans) and inorganic compounds (e.g., nitrate, 

sulfate) to terrestrial and aquatic ecosystems. The chemical form of the compounds 

deposited depends on a variety of factors including ambient conditions (e.g., temperature, 

humidity, oxidant levels) and the sources of the material. Chemical and physical 

transformations of the compounds occur in the atmosphere as well as the media onto 

which they deposit. These transformations in turn influence the fate, bioavailability and 

potential toxicity of these compounds. Atmospheric deposition has been identified as a 

key component of the environmental and human health hazard posed by several 

pollutants including mercury, dioxin and PCBs.189

 

187 64 FR 35714 (July 1, 1999). 

188 62 FR 38680-38681 (July 18, 1997).

189 U.S. EPA. (2000). Deposition of Air Pollutants to the Great Waters: Third Report to Congress. Office of 

Air Quality Planning and Standards. EPA-453/R-00-0005. 
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Adverse impacts on water quality can occur when atmospheric contaminants 

deposit to the water surface or when material deposited on the land enters a waterbody

through runoff. Potential impacts of atmospheric deposition to waterbodies include those 

related to both nutrient and toxic inputs. Adverse effects to human health and welfare 

can occur from the addition of excess nitrogen via atmospheric deposition. The nitrogennutrient enrichment contributes to toxic algae blooms and zones of depleted oxygen, 

which can lead to fish kills, frequently in coastal waters. Deposition of heavy metals or 

other toxics may lead to the human ingestion of contaminated fish, impairment of 

drinking water, damage to freshwater and marine ecosystem components, and limits to 

recreational uses. Several studies have been conducted in U.S. coastal waters and in the 

Great Lakes Region in which the role of ambient PM deposition and runoff is 

investigated.190,191,192,193,194 

Atmospheric deposition of nitrogen and sulfur contributes to acidification, 

altering biogeochemistry and affecting animal and plant life in terrestrial and aquatic

ecosystems across the United States. The sensitivity of terrestrial and aquatic ecosystems 

to acidification from nitrogen and sulfur deposition is predominantly governed by

geology. Prolonged exposure to excess nitrogen and sulfur deposition in sensitive areas 

acidifies lakes, rivers and soils. Increased acidity in surface waters creates inhospitable 

conditions for biota and affects the abundance and nutritional value of preferred prey

species, threatening biodiversity and ecosystem function. Over time, acidifying

deposition also removes essential nutrients from forest soils, depleting the capacity of 

soils to neutralize future acid loadings and negatively affecting forest sustainability. 

Major effects include a decline in sensitive forest tree species, such as red spruce (Picea 

rubens) and sugar maple (Acer saccharum), and a loss of biodiversity of fishes, 

zooplankton, and macro invertebrates.

In addition to the role nitrogen deposition plays in acidification, nitrogen 

deposition also leads to nutrient enrichment and altered biogeochemical cycling. In 

aquatic systems increased nitrogen can alter species assemblages and cause 

eutrophication. In terrestrial systems nitrogen loading can lead to loss of nitrogen 

sensitive lichen species, decreased biodiversity of grasslands, meadows and other 

sensitive habitats, and increased potential for invasive species. For a broader explanation 

of the topics treated here, refer to the description in Section 6.3.2 of the RIA.

 

190 U.S. EPA. (2004). National Coastal Condition Report II. Office of Research and Development/ Office of 

Water. EPA-620/R-03/002. 

191 Gao, Y., E.D. Nelson, M.P. Field, et al. (2002). Characterization of atmospheric trace elements on 

PM2.5 particulate matter over the New York-New Jersey harbor estuary. Atmos. Environ. 36: 1077-1086. 

192 Kim, G., N. Hussain, J.R. Scudlark, and T.M. Church. (2000). Factors influencing the atmospheric 

depositional fluxes of stable Pb, 210Pb, and 7Be into Chesapeake Bay. J. Atmos. Chem. 36: 65-79. 

193 Lu, R., R.P. Turco, K. Stolzenbach, et al. (2003). Dry deposition of airborne trace metals on the Los 

Angeles Basin and adjacent coastal waters. J. Geophys. Res. 108(D2, 4074): AAC 11-1 to 11-24. 

194 Marvin, C.H., M.N. Charlton, E.J. Reiner, et al. (2002). Surficial sediment contamination in Lakes Erie 

and Ontario: A comparative analysis. J. Great Lakes Res. 28(3): 437-450. 
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Adverse impacts on soil chemistry and plant life have been observed for areas 

heavily influenced by atmospheric deposition of nutrients, metals and acid species, 

resulting in species shifts, loss of biodiversity, forest decline, damage to forest 

productivity and reductions in ecosystem services. Potential impacts also include adverse 

effects to human health through ingestion of contaminated vegetation or livestock (as in 

the case for dioxin deposition), reduction in crop yield, and limited use of land due to 

contamination. 

Atmospheric deposition of pollutants can reduce the aesthetic appeal of buildings 

and culturally important articles through soiling, and can contribute directly (or in 

conjunction with other pollutants) to structural damage by means of corrosion or erosion. 

Atmospheric deposition may affect materials principally by promoting and accelerating 

the corrosion of metals, by degrading paints, and by deteriorating building materials such 

as concrete and limestone. Particles contribute to these effects because of their 

electrolytic, hygroscopic, and acidic properties, and their ability to adsorb corrosive gases 

(principally sulfur dioxide). 
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i. Current Nitrogen and Sulfur Deposition

Over the past two decades, the EPA has undertaken numerous efforts to reduce 

nitrogen and sulfur deposition across the U.S. Analyses of long-term monitoring data for 

the U.S. show that deposition of both nitrogen and sulfur compounds has decreased over 

the last 19 years.195 The data show that reductions were more substantial for sulfur 

compounds than for nitrogen compounds. In the eastern U.S., where data are most 

abundant, total sulfur deposition decreased by about 44 percent between 1990 and 2007, 

while total nitrogen deposition decreased by 25 percent over the same time frame.196 

These numbers are generated by the U.S. national monitoring network and they likely 

underestimate nitrogen deposition because neither ammonia nor organic nitrogen is 

measured. Although total nitrogen and sulfur deposition has decreased over time, many

areas continue to be negatively impacted by deposition. Deposition of inorganic nitrogen 

and sulfur species routinely measured in the U.S. between 2005 and 2007 were as high as 

9.6 kilograms of nitrogen per hectare (kg N/ha) averaged over three years and 20.8 

kilograms of sulfur per hectare (kg S/ha) averaged over three years.197

d. Environmental Effects of Air Toxics

Emissions from producing, transporting and combusting fuel contribute to 

ambient levels of pollutants that contribute to adverse effects on vegetation. Volatile 

organic compounds, some of which are considered air toxics, have long been suspected to 

play a role in vegetation damage.198 In laboratory experiments, a wide range of tolerance 

to VOCs has been observed.199 Decreases in harvested seed pod weight have been 

reported for the more sensitive plants, and some studies have reported effects on seed 

germination, flowering and fruit ripening. Effects of individual VOCs or their role in 

conjunction with other stressors (e.g., acidification, drought, temperature extremes) have 

not been well studied. In a recent study of a mixture of VOCs including ethanol and 

 

195 U.S. EPA. (2013). U.S. EPA’s Report on the Environment. Data accessed online November 25, 2013 at: 

http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewInd&lv=list.listBySubTopic&r=216610&subto

p=341&ch=46. 

196 U.S. EPA. (2012). U.S. EPA’s Report on the Environment. Data accessed online February 15, 2012 at: 

http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewPDF&ch=46&lShowInd=0&subtop=341&lv=li

st.listByChapter&r=216610. 

197 U.S. EPA. (2012). U.S. EPA's Report on the Environment. Data accessed online February 15, 2012 at: 

http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewPDF&ch=46&lShowInd=0&subtop=341&lv=li

st.listByChapter&r=216610. 

198 U.S. EPA. (1991). Effects of organic chemicals in the atmosphere on terrestrial plants. EPA/600/3-

91/001. 

199 Cape JN, ID Leith, J Binnie, J Content, M Donkin, M Skewes, DN Price AR Brown, AD Sharpe. 

(2003). Effects of VOCs on herbaceous plants in an open-top chamber experiment. Environ. Pollut. 

124:341-343. 
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toluene on herbaceous plants, significant effects on seed production, leaf water content 

and photosynthetic efficiency were reported for some plant species.200

Research suggests an adverse impact of vehicle exhaust on plants, which has in 

some cases been attributed to aromatic compounds and in other cases to nitrogen 

oxides.201,202, 203

III. How Would This Rule Reduce Emissions and Air

Pollution?

A. Effects of the Vehicle and Fuel Changes on Mobile Source Emissions

The Tier 3 vehicle and fuel standards will significantly reduce the tailpipe and 

evaporative emissions of light- and heavy-duty vehicles in several ways, as described in 

this section. In addition, the gasoline sulfur standard will reduce emissions of SO2 from 

existing gasoline-powered vehicles and equipment. As described in Section II, all of 

these emission reductions will in turn improve air quality nationwide and reduce the 

health effects associated with air pollution from mobile sources.

As with the Tier 2 program, EPA is implementing closely-coordinated 

requirements for both automakers and refiners in the same rulemaking action. The Tier 3 

vehicle emission standards and gasoline sulfur standards represent a “systems approach” 

to reducing vehicle-related exhaust and evaporative emissions. By recognizing the 

relationships among the various sources of emissions addressed by this action, we have 

been able to integrate the provisions into a single, coordinated program. 

1. How Do Vehicles Produce the Emissions Addressed in this Action?

The degree to which vehicles produce exhaust and evaporative emissions depends 

on the design and functionality of the engine and the associated exhaust and evaporative 

emission controls, in concert with the properties of the fuel on which the vehicle is 

operating. In the following paragraphs, we discuss how light- and heavy-duty vehicles 

produce each of these types of emissions, both from the tailpipe and from the fuel system. 

 

200 Cape JN, ID Leith, J Binnie, J Content, M Donkin, M Skewes, DN Price AR Brown, AD Sharpe. 

(2003). Effects of VOCs on herbaceous plants in an open-top chamber experiment. Environ. Pollut. 

124:341-343. 

201 Viskari E-L. (2000). Epicuticular wax of Norway spruce needles as indicator of traffic pollutant 

deposition. Water, Air, and Soil Pollut. 121:327-337. 

202 Ugrekhelidze D, F Korte, G Kvesitadze. (1997). Uptake and transformation of benzene and toluene by 

plant leaves. Ecotox. Environ. Safety 37:24-29. 

203 Kammerbauer H, H Selinger, R Rommelt, A Ziegler-Jons, D Knoppik, B Hock. (1987). Toxic 

components of motor vehicle emissions for the spruce Picea abies. Environ. Pollut. 48:235-243. 
Page 72 of 529

a. Tailpipe (Exhaust) Emissions

The pollutants emitted at the vehicle’s tailpipe and their quantities depend on 

how the fuel is combusted in the engine and how the resulting gases are treated in the 

exhaust system. Historically, much of tailpipe emission control has focused on 

hydrocarbon compounds (HC) and NOX. The portion of hydrocarbons that is methane is 

minimally reactive in forming ozone. Thus, for emission control purposes, the focus is 

generally on non-methane hydrocarbons (NMHC), which are also expressed as nonmethane organic gases (NMOG) in order to account for oxygenates (usually ethanol) now 

usually present in the fuel. 

Tailpipe hydrocarbon emissions also include several toxic pollutants, including 

benzene, acetaldehyde, and formaldehyde. To varying degrees, the mass emissions of 

these pollutants are reduced along with other hydrocarbons by the catalytic converter and 

improved engine controls. 

Light- and heavy-duty gasoline vehicles also emit PM and CO. PM forms 

directly as a combustion product (as elemental carbon or soot) and indirectly as semivolatile hydrocarbon compounds that form particles in the exhaust system or soon after 

exiting the tailpipe. CO is a product of incomplete fuel combustion.

When operating properly, modern exhaust emission controls (centering on the 

catalytic convertor) can reduce much of the HC (including toxics), NOX and CO exiting 

the engine. However, tailpipe emissions are increased during periods of vehicle startup, 

as catalytic convertors must warm up to be effective; during subsequent operation due to 

the interference of sulfur in the gasoline; during high load operating events, as the 

catalyst is overwhelmed or its operation is modified to protect against permanent damage; 

and as a vehicle ages, as the catalyst degrades in performance due to the effects of high 

temperature operation and contaminants in the fuel and lubricating oil. 

b. Evaporative Emissions

Gasoline vehicles also produce vapors in the fuel tank and fuel system that can be 

released as evaporative emissions. These vapors are primarily the lighter, more volatile 

hydrocarbon compounds in gasoline. As discussed in Section IV below, vehicle 

evaporative (“evap”) control systems are designed to block or capture vapors as they are 

generated. Vapors are generated in the vehicle fuel tank and fuel system (and released to 

the atmosphere if not adequately controlled) as fuel heats up due to ambient temperature 

increase and/or vehicle operation. Fuel vapors are also released when they permeate 

through elastomers in the fuel system, when they leak at connections or due to damaged 

components, and during refueling events. 

In general, the evap emission controls on current vehicles (and that will be 

improved under this action) consist of a canister filled with activated charcoal and 

connected by hoses to the fuel system. The hoses direct generated vapors to the canister, 
Page 73 of 529

which collects the vapors on the carbon and stores them until the system experiences a 

“purge” event. During purge, the engine draws fresh air through the canister, carrying 

vapors released by the carbon to the engine to be combusted and restoring the capacity of 

the canister. Evaporative emissions occur when vapors are emitted to the atmosphere 

because the evap system is compromised, the carbon canister is overwhelmed, or vapors 

permeate or leak. As such, evaporative emission controls also involve proper material 

selection for fuel system components, careful design of these components, and onboard 

diagnostics to check the system for failure. 

2. How Will the Changes to Gasoline Sulfur Content Affect Vehicle Emissions?

Gasoline vehicles rely on highly efficient aftertreatment catalysts to control 

tailpipe emissions of harmful pollutants like CO and NOX, as well as VOCs that include 

air toxics and precursor compounds to ozone and secondary PM in the atmosphere. 

These catalysts utilize finely-dispersed precious metals that are susceptible to 

deactivation by sulfur compounds in the exhaust. Studies have repeatedly demonstrated 

that the presence of even a tiny amount of sulfur in fuel has a measurable impact on the 

ability of the catalyst to control emissions, and that emission levels of most pollutants, 

especially NOx, are very sensitive to fuel sulfur.204,205 

Sulfur naturally occurs in crude oil and is carried through the refining process into 

gasoline. EPA’s Tier 2 rulemaking for light-duty vehicles, published in 2000, required 

refiners to reduce sulfur levels in gasoline to an average of 30 ppm, a reduction of about 

90 percent from the in-use baseline. At the time, there were indications that sulfur 

reductions below 30 ppm may provide additional emission benefits. However, the data 

was insufficient to quantify the benefits to the existing fleet, and the Tier 2 vehicle 

standards could be achieved without lowering sulfur below 30 ppm.

206

As discussed in Section IV.A.6, subsequent research provides a compelling case 

that even this level of sulfur degrades the emission performance of vehicles on the road 

today and inhibits necessary further reductions in vehicle emissions performance, which 

depend on optimum catalyst performance to reach emission targets. A study conducted 

by EPA and the auto industry in support of the Mobile Source Air Toxics (MSAT) rule 

found significant reductions in NOX, CO and total HC when nine Tier 2 vehicles were 

tested on ultra-low sulfur fuel.207 In particular, the study found a 32 percent decrease in 

NOX when sulfur was reduced from 32 ppm to 6 ppm (equivalent to a 25 percent

 

204 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, EPA420-R-14-002.

205 Durbin, T., “The Effect of Fuel Sulfur on NH3 and Other Emissions from 2000-2001 Model Year 

Vehicles”, May 2003. Published as Report E-60 by the Coordinating Research Council, Alpharetta, GA.

206 65 FR 6698 (February 10, 2000)

207 Regulatory Impact Analysis for the Control of Hazardous Air Pollutants from Mobile Sources Final 

Rule, EPA 420-R-07-002, Chapter 6
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decrease if sulfur levels were reduced from 30 to 10 ppm, assuming a linear effect). 

Another recent study by Umicore showed reductions of 41 percent for NOX and 17 

percent for hydrocarbons on a PZEV operating on fuel with 33 ppm and 3 ppm fuel

(equivalent to reductions of 27 percent and 11 percent, respectively, if sulfur levels were 

reduced from 30 to 10 ppm, assuming a linear effect).208 

A larger study of Tier 2 vehicles recently completed by EPA confirmed these 

results, showing significant reductions in FTP-composite NOX (14 percent), CO (10 

percent) and total HC (15 percent) on the 5 ppm fuel, relative to 28 ppm fuel (equivalent 

to 12 percent, 9 percent, and 13 percent reduction, respectively, if sulfur levels were 

reduced from 30 to 10 ppm, assuming a linear effect).

209

 For NOX, the majority of 

overall reductions were driven by large reductions on warmed-up periods of the test cycle 

(Bag 2), which showed a 52 percent reduction using 5 ppm fuel relative to 28 ppm fuel 

(equivalent to 45 percent reduction if sulfur levels were reduced from 30 to 10 ppm, 

assuming a linear effect), consistent with the role of sulfur in catalyst degradation 

discussed above. For additional details regarding these results, please see Section 

IV.A.6.c.

Our application of these study results assumes a linear effect of sulfur level on 

catalyst efficiency between the high and low sulfur test fuels. This is reasonable given 

that the mass flow rate of sulfur in exhaust gas changes in proportion to its concentration 

in the fuel, and that the chemical kinetics of adsorption of sulfur to the precious metal 

sites is approximately first order. Linearity of effect is also supported by past studies 

with multiple fuel sulfur levels such as the CRC E-60 and 2000 AAM/AIAM/Oil 

Industry emission test programs.

210,211

Based on these analyses, the benefits of the Tier 3 sulfur standard are significant 

in two ways: they enable vehicles designed to the Tier 3 tailpipe exhaust standards to 

meet these standards for the duration of their useful life, and they facilitate immediate 

emission reductions from all the vehicles on the road at the time the sulfur controls are 

implemented. 

B. How Will Emissions Be Reduced?

The Tier 3 standards will reduce emissions of VOC, NOX (including NO2), direct 

PM2.5, CO, SO2, and air toxics. The sulfur standards will reduce emissions from the on-

 

208 Ball D., Clark D., Moser D. (2011), Effects of Fuel Sulfur on FTP NOx Emissions from a PZEV 4 

Cylinder Application. SAE 2011 World Congress Paper 2011-01-0300

209 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, EPA420-R-14-002. 

210 Durbin, T., “The Effect of Fuel Sulfur on NH3 and Other Emissions from 2000-2001 Model Year 

Vehicles”, May 2003. Published as Report E-60 by the Coordinating Research Council, Alpharetta, GA.

211 “AAM/AIAM/Oil Industry Low Sulfur & Oxygenate Test Program”, 2000, last accessed on 01/15/14 at 

the following URL: http://www.arb.ca.gov/fuels/gasoline/carfg3/aam_prstn.pdf.
Page 75 of 529

road fleet immediately upon implementation in calendar year 2017. The vehicle 

standards will begin to reduce emissions as the cleaner cars and trucks begin to enter the 

fleet in model year 2017 and model year 2018, respectively. The magnitude of reduction

will grow as more Tier 3 vehicles enter the fleet. We present emission reductions in 

calendar year 2018 to reflect the early reductions expected from the Tier 3 standards, and 

in calendar year 2030, when 70 percent of the miles travelled are from vehicles that meet 

the fully phased-in Tier 3 standards. Although 2030 is the farthest year that is feasible 

for air quality modeling, the full reduction of the vehicle program will be realized after 

2030, when the fleet has fully turned over to vehicles that meet the fully phased-in Tier 3 

standards; thus we present emission reductions projected in 2050 as well (see Chapter 7 

of the RIA). 

Emission reductions are estimated on an annual basis, for all 50 U.S. states plus 

the District of Columbia, Puerto Rico and the U.S. Virgin Islands. The reductions were 

estimated using a version of EPA’s MOVES model updated for this analysis, as described 

in detail in Chapter 7 of the RIA. This version of MOVES includes our most recent data 

on how vehicle emissions are affected by changes in sulfur, ethanol, RVP, and other fuel 

properties. We estimated emission reductions compared to a reference case that assumed 

renewable fuel volumes and ethanol blends based on the U.S. Energy Information 

Administration’s Annual Energy Outlook 2013 (AEO2013).212 As described in Chapter 7 

of the RIA, the reference and control scenarios based on AEO2013 reflect a mix of E10,

E15, and E85 in both 2018 and 2030. The reference case assumed an average sulfur level 

of 30 ppm (10 ppm in California) and continuation of the Tier 2 vehicle program 

indefinitely, with the exception of California and Section 177 states that have adopted the 

LEV III program.

The analysis described here accounts for the following national onroad rules:

 Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control 

Requirements (65 FR 6698, February 10, 2000)

 Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel 

Sulfur Control Requirements (66 FR 5002, January 18, 2001)

 Mobile Source Air Toxics Rule (72 FR 8428, February 26, 2007)

 Regulation of Fuels and Fuel Additives: Changes to Renewable Fuel 

Standard Program (75 FR 14670, March 26, 2010)

 

212 U.S. Energy Information Administration, Annual Energy Outlook (April 15, 2013)
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 Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate 

Average Fuel Economy Standards for 2012-2016 (75 FR 25324, May 7, 

2010)

 Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for 

Medium- and Heavy-Duty Engines and Vehicles (76 FR 57106, 

September 15, 2011)

 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas 

Emissions and Corporate Average Fuel Economy Standards (77 FR 

62623, October 15, 2012)

The analysis also accounts for many other national rules and standards. In addition, the 

modeling accounts for state and local rules including California’s most recent Low 

Emission Vehicle (LEV III) program adopted in California and twelve other states (also 

referred to as Section 177 states),213 local fuel standards, Inspection/Maintenance 

programs, Stage II refueling controls, the National Low Emission Vehicle Program 

(NLEV), and the Section 177 states LEV and LEV II programs. See the Tier 3 emissions 

modeling TSD for more detail.

A summary of emission reductions projected to result from Tier 3, relative to the 

reference case, is shown in calendar years 2018 and 2030 for NOX, VOC, direct PM2.5, 

CO, SO2, and total air toxics in Table III-1. For many pollutants, the immediate 

reductions in 2018 are significant; for example, combined NOX and VOC emissions will

be reduced by over 300,000 tons. By 2030, combined NOX and VOC emissions will be 

reduced by roughly 500,000 tons, one quarter of the onroad inventory. Many of the 

modeled air toxics will be significantly reduced as well, including benzene, 1,3-

butadiene, acetaldehyde, acrolein and ethanol (ranging from 10 to nearly 30 percent of 

the national onroad inventory by 2030). The relative reduction in overall emissions will

continue to increase beyond 2030 as more of the fleet continues to turn over to Tier 3 

vehicles; for example, by 2050, when nearly all of the fleet will have turned over to 

vehicles meeting the fully phased-in Tier 3 standards, we estimate the Tier 3 program 

will reduce onroad emissions of NOX and VOC nearly 31 percent from the level of 

emissions projected without Tier 3 controls. 

Table III-1 Estimated Emission Reductions from the Tier 3 Standards 

(Annual U.S. Short Tons)

2018 2030

Tons % of Tons % of 

 

213 These states include Connecticut, Delaware, Maryland, Maine, Massachusetts, New Jersey, New York, 

Oregon, Pennsylvania, Rhode Island, Washington, and Vermont.
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Onroad 

Inventory

Onroad 

Inventory

NOX 264,369 10% 328,509 25%

VOC 47,504 3% 167,591 16%

CO 278,879 2% 3,458,041 24%

Direct PM2.5 130 0.1% 7,892 10%

Benzene 1,916 6% 4,762 26%

SO2 14,813 56% 12,399 56%

1,3-Butadiene 257 5% 677 29%

Formaldehyde 513 2% 1,277 10%

Acetaldehyde 600 3% 2,067 21%

Acrolein 40 3% 127 15%

Ethanol 2,704 2% 19,950 16%

Reductions for each pollutant are discussed in the following sections, focusing on 

the contribution of program elements to the total reductions summarized above. 

1. NOX

The Tier 3 sulfur standards will significantly reduce NOX emissions immediately

upon implementation of the program. As discussed above, recent research on the impact 

of sulfur on Tier 2 technology vehicles shows the potential for significant reductions in 

NOX emissions from the existing fleet of Tier 2 vehicles by lowering sulfur levels to 10 

ppm. Prior research shows that NOX emissions will also be expected to decrease from 

the fleet of older (pre-Tier 2) light-duty vehicles as well as heavy-duty gasoline 

vehicles,214 although to a lesser extent than for Tier 2 vehicles. 

Table III-2 shows the reduction in NOX emissions, in annual short tons, projected 

in calendar years 2018 and 2030. The reductions are split into those attributable to the 

introduction of low sulfur fuel in the pre-Tier 3 fleet (defined for this analysis as model 

years prior to 2017); and reductions attributable to vehicle standards enabled by low 

sulfur fuel (model year 2017 and later). As shown, upon implementation of the Tier 3 

sulfur standards, total onroad NOX emissions are projected to drop 10 percent. This is 

primarily due to large reductions from Tier 2 gasoline vehicles, which contribute about 

one-quarter of the NOX emissions from the on-road fleet in 2018. The relative reduction 

grows as cleaner vehicles turn over into the fleet. By 2030, we project that the reduction 

in overall onroad NOX inventory will be 25 percent.

Table III-2 Projected NOX Reductions from Tier 3 Program (Annual U.S. Tons)

2018 2030

 

214 Rao, V. (2001), Fuel Sulfur Effects on Exhaust Emissions: Recommendations for MOBILE6, EPA420-R-01-039
Page 78 of 529

Total reduction 264,369 328,509

Reduction from pre-Tier 3 

fleet due to sulfur standard

242,434 56,324

Reduction from Tier 3 fleet 

due to vehicle and sulfur 

standards 

21,934 272,185

Percent reduction in 

onroad NOX emissions

10% 25%

2. VOC

Table III-3 shows the reduction in VOC emissions, in annual short tons, projected 

in calendar years 2018 and 2030 resulting from the Tier 3 standards. In 2018, as with 

NOX, we project reductions from the pre-Tier 3 fleet with the fuel standards. By 2030,

the reduction in overall onroad VOC emissions will be 16 percent, the majority of this 

from the vehicles meeting the fully phased-in Tier 3 standards. The evaporative standards 

are projected to account for roughly one third of the overall vehicle program reduction in 

2030. 

Table III-3 Projected VOC Reductions from Tier 3 Program (Annual U.S. Tons)

2018 2030

Total reduction 47,504 167,591

Reduction from pre-Tier 3 

fleet due to sulfur standard

38,786 11,249

Reduction from Tier 3 fleet 

due to vehicle and sulfur 

standards 

8,718 156,343

Exhaust 43,009 105,253

Evaporative 4,495 62,339

Percent reduction in 

onroad VOC emissions

3% 16%

3. CO

Table III-4 shows the reductions for CO, broken down by pre- and post-Tier 3 in 

the manner described for NOX and VOC above. In contrast to NOx and VOC, the 

immediate CO reductions in the onroad fleet from sulfur control in 2018 are small, based 

on research showing that fuel sulfur level has a minimal impact on CO emissions from 

Tier 2 vehicles. The CO exhaust standards are projected to reduce onroad CO emissions 

by 24 percent in 2030. 

Table III-4 Projected CO Reductions from Tier 3 Program (Annual U.S. Tons)

2018 2030

Total reduction 278,879 3,458,041
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Reduction from pre-Tier 3 

fleet due to sulfur standard

122,171 17,734

Reduction from Tier 3 fleet 

due to vehicle and sulfur 

standards

156,708 3,440,307

Percent reduction in 

onroad CO emissions

2% 24%

4. Direct PM2.5

Reductions in direct emissions of PM2.5 are projected to result solely from the 

vehicle tailpipe standards, so meaningful reductions are realized mainly as the fleet turns 

over. By 2030, we project a reduction of about 7,900 tons annually, which represents 

approximately 10 percent of the onroad direct PM2.5 inventory. The relative reduction in 

onroad emissions is projected to grow to 28 percent in 2050, when nearly all of the fleet 

will have turned over to vehicles meeting the fully phased-in Tier 3 standards. 

Reductions in NOX and VOC emissions will also reduce secondary PM formation, which 

is quantified as part of the air quality analysis described in Section III.C. 

5. Air Toxics

Emissions of air toxics also will be reduced by the sulfur, exhaust and evaporative 

standards. Air toxics are generally a subset of compounds making up VOC, so the 

reduction trends tend to track the VOC reductions presented above, for most air toxics. 

Table III-5 presents reductions for certain key air toxics, and Table III-6 presents 

reductions for the sum of 71 different toxic compounds. 

Table III-5 Reductions for Certain Individual Compounds (Annual U.S. Tons)

Tons 

Reduced in 

2018

% Reduction 

in Onroad 

Emissions

Tons Reduced 

in 2030

% Reduction in 

Onroad 

Emissions

Benzene 1,916 6% 4,762 26%

Acetaldehyde 600 3% 2,067 21%

Formaldehyde 513 2% 1,277 10%

1,3-Butadiene 257 5% 677 29%

Acrolein 40 3% 127 15%

Naphthalene 99 3% 269 15%

Ethanol 2,704 2% 19,950 16%

The totals shown in Table III-6 represent the sum of 71 species including the 

toxics in Table III-5, 15 polycyclic aromatic hydrocarbon (PAH) compounds in gas and 

particle phase, and additional gaseous compounds such as toluene, xylenes, styrene, 
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hexane, 2,2,4-trimethylpentane, n-hexane, and propionaldehyde (see Appendix 7A of the 

RIA). As shown, in 2030, the overall onroad inventory of total toxics will be reduced by 

15 percent, with nearly one half of the vehicle program reductions coming from the 

evaporative standards. 

Table III-6 Reductions in Total Mobile Source Air Toxics (Annual U.S. Tons)

2018 2030

Total reduction 15,583 64,558

Reduction from pre-Tier 3 

fleet due to sulfur standard

11,981 3,517

Reduction from Tier 3 fleet 

due to vehicle and sulfur 

standards

3,602 61,041

Exhaust 13,340 34,595

Evaporative 2,243 29,963

Percent reduction in 

onroad toxics emissions

3% 15%

6. SO2

SO2 emissions from mobile sources are a direct function of sulfur in the fuel, and 

reducing sulfur in gasoline will result in immediate reductions in SO2 from the on and 

off-road fleet. The reductions, shown in Table III-7, are a function of the sulfur level and 

fuel consumption. This is reflected in the relative contribution of on-road vehicles and 

off-road equipment, where off-road gasoline consumption accounts for approximately 5 

percent of overall gasoline use.215

Table III-7 Projected SO2 Reductions from Tier 3 Program (Annual U.S. Tons)

2018 2030

Total reduction 15,565 13,261

Reduction from onroad 

vehicles due to sulfur 

standard

14,813 12,399

Reduction from off-road 

equipment due to sulfur 

standard

752 862

Percent reduction in 

onroad SO2 emissions

56% 56%

 

215 U.S. Energy Information Administration, Annual Energy Outlook 2013 (April 15, 2013)
Page 81 of 529

7. Greenhouse Gases

Reductions in nitrous oxide (N2O) emissions and methane (CH4) emissions, both 

potent greenhouse gas emissions, are projected for gasoline cars and trucks as a result of 

the sulfur and tailpipe standards. A study conducted by the University of CaliforniaRiverside found a 29 percent reduction in N2O emissions over the FTP when sulfur was 

reduced from 30 to 5 ppm,216 while EPA research described in Section IV.A.6 on sulfur 

effects found a 26 percent reduction in CH4 emissions when sulfur was reduced from 28 

to 5 ppm.

217

 

Several studies have established correlations between reductions in tailpipe NOX

emissions and reductions in N2O from gasoline cars and trucks,218,219,220,221 as well as 

correlations between reductions in tailpipe HC emissions and reductions in CH4.

222,223

Studies by Winer, et al (2005) and Behrentz et al (2004) reported N2O: NOX ratios of 

0.06 and 0.095, respectively, and supported the application of N2O: NOX ratios to NOX

emissions as a reasonable method for estimating N2O emission inventories. CARB has 

also used N2O: NOX ratio to develop the N2O emissions inventories for the LEV III 

program, based on a regression analysis suggesting N2O: NOX ratio of 0.04, on 

average.224 

As detailed in Chapter 7.3 of the RIA, the N2O reductions are estimated by 

employing two different methodologies, resulting in a range of reductions. The first 

method applies the relationship between N2O and NOX from a regression model225 to 

NOX inventories from both Tier 3 and pre-Tier 3 vehicles. The second method applies 

 

216 Huai, et al. (2004), Estimates of the emission rates of nitrous oxide from light-duty vehicles using 

different chassis dynamometer test cycles, Atmospheric Environment 6621-6629 

217 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, EPA420-R-14-002,

218 Michaels, H. (1998) Emissions of Nitrous Oxide from Highway Mobile Sources, U.S. EPA EPA420-R98-009 

219 Behrentz, et al. (2004), Measurements of nitrous oxide emissions from light-duty motor vehicles: a pilot 

study, Atmospheric Environment 4291-4303 

220 Meffert, et. al (2000) Analysis of Nitrous Oxide Emissions from Light Duty Passenger Cars, SAE 2000-

01-1952

221 Winer, et al. (2005) Estimates of Nitrous Oxide Emissions and the Effects of Catalyst Composition and 

Aging, State of California Air Resources Board 02-313

222 Meszler, D. (2004), Light Duty Vehicle Methane and Nitrous Oxide Emissions: Greenhouse Gas 

Impacts, Study for Northeast States Center for a Clean Air Future

223 Graham, L., Greenhouse Gas Emissions from 1997-2005 Model Year Light Duty Vehicles, 

Environment Canada ERMD Report #04-44 

224 LEV III Moblie Source Emissions Inventory Technical Support Document – Appendix T, January 2012, 

last accessed on 01/15/14 at the following URL: 

http://www.arb.ca.gov/regact/2012/leviiighg2012/levappt.pdf

225 U.S. EPA, 2014, Memorandum to Docket: Regression Analysis of Nitrous Oxide and Oxides of 

Nitrogen from Motor Vehicles.
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the regression of N2O and NOX only to Tier 3 vehicles and uses the UC Riverside sulfur 

results to estimate the N2O reductions from pre-Tier 3 vehicles. Using a 100-year global 

warming potential of 298 for N2O according to the 2007 IPCC AR4,

226 the estimated N2O 

reduction is 2.2 million metric tons of carbon dioxide equivalent (MMTCO2e) in 2018, 

growing to the range between 3.8 to 4.0 MMTCO2e in 2030. For 2018, there was an 

agreement between the two methodologies described above, resulting in a single 

estimate. MOVES can be used to directly estimate CH4 reductions from the sulfur and 

vehicle standards, estimating an additional 0.1 MMTCO2e reduction in 2018, growing to 

0.3 MMTCO2e in 2030. The total GHG reduction from the Tier 3 rule is 2.3 MMTCO2e 

in 2018, and between 4.1 and 4.3 MMTCO2e in 2030. 

These reductions will be partially offset by CO2 emissions associated with higher 

energy use required in the process of removing sulfur within the refinery. As an 

extension of our refinery-by-refinery cost modeling described in Section VII.B., we 

calculated the CO2 emission impacts of Tier 3 gasoline sulfur control. We estimated 

refinery-specific changes in process energy and then applied emission factors that 

correspond to those changes, on a refinery-by-refinery basis. As described in Chapter 4.5 

of the RIA, the results showed an increase of up to 1.9 MMTCO2e in 2018 and 1.6 

MMTCO2e in 2030 for all U.S. refineries complying with the lower sulfur standards 

assuming that the sulfur standards are fully phased-in. In 2018, the combined impact of

CH4 and N2O emission reductions from the vehicles and CO2 emission increases from the 

refineries shows a slight net decrease on a CO2 equivalent basis. While still small, this 

net decrease grows to a range between 2.5 to 2.7 MMTCO2e by 2030.

We do not expect the Tier 3 vehicle standards to result in any discernible changes 

in vehicle CO2 emissions or fuel economy. Emissions of the pollutants that are controlled 

by the Tier 3 program – NMOG, NOX, and PM – are not a function of the amount of fuel 

consumed, since manufacturers need to design their catalytic emission control systems to 

reduce these emissions regardless of their engine-out levels. 

C. How Will Air Pollution Be Reduced? 

Reductions in emissions of NOX, VOC, PM2.5 and air toxics expected as a result 

of the Tier 3 standards are projected to lead to significant improvements in air quality. 

The air quality modeling predicts significant improvements in ozone concentrations due 

to the Tier 3 standards. Ambient PM2.5 and NO2 concentrations are also expected to 

 

226 The global warming potentials (GWP) used in this rule are consistent with the 100-year time frame 

values in the 2007 Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). 

At this time, the 1996 IPCC Second Assessment Report (SAR) 100-year GWP values are used in the 

official U.S. greenhouse gas inventory submission to the United Nations Framework Convention on 

Climate Change (per the reporting requirements under that international convention, which were last 

updated in 2006). N2O has a 100-year GWP of 298 and CH4 has a 100-year GWP of 25 according to the 

2007 IPCC AR4.
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improve as a result of the Tier 3 program. Decreases in ambient concentrations of air 

toxics are projected with the Tier 3 standards, including notable nationwide reductions in 

benzene concentrations. Our air quality modeling also predicts improvements in 

visibility and sulfur deposition, as well as substantial decreases in nitrogen deposition as 

a result of the Tier 3 standards. The results of our air quality modeling of the impacts of 

the Tier 3 rule are summarized in the following section. 

1. Ozone

The air quality modeling done for this action projects that in 2018, with all current

and required controls in effect but excluding the emissions changes expected to occur as a 

result of the Tier 3 standards or any other additional controls, at least 19 counties, with a 

projected population of over 37 million people, would have projected design values 

above the level of the 2008 8-hour ozone standard of 75 ppb. In 2030 the modeling 

projects that in the absence of Tier 3 standards or any other additional controls there will

be 6 counties with a population of over 19 million people with projected design values 

above the level of the 2008 8-hour ozone standard of 75 ppb. An additional 37 million 

people will be living in the 43 counties that will be close to (within 10 percent of) the 

level of the ozone standard. 

Air quality modeling indicates that this action will meaningfully decrease ozone 

design value concentrations in many areas of the country, including those that are 

projected to be exceeding, or close to exceeding, the ozone standard. In 2018, the 

majority of the design value decreases are between 0.5 and 1.0 ppb. In 2030, the Tier 3

rule will result in larger decreases in ozone design values, with the majority of counties 

projecting decreases of between 0.5 and 1.0 ppb, and over 250 more counties with 

decreases greater than 1.0 ppb. Since the Tier 3 standards go into effect during the period 

when some areas are still working to attain the ozone NAAQS, the projected air quality

changes will help state and local agencies in their effort to attain and maintain the ozone 

standard. 

2. Particulate Matter

The air quality modeling conducted for this action projects that in 2018, with all 

current controls in effect but excluding the emissions changes expected to occur as a 

result of Tier 3 standards or any other additional controls, at least 14 counties, with a 

projected population of over 20 million people, would have projected design values 

above the level of the annual standard of 12 μg/m3 and at least 24 counties, with a 

projected population of over 18 million people, would have projected design values 

above the level of the 24-hour standard of 35 μg/m3. In 2030, the modeling projects that 

in the absence of Tier 3 standards or any other additional controls there will be 13

counties, with a projected population of over 21 million people, with projected design 

values above the level of the annual standard of 12 μg/m3 and 18 counties, with a 

projected population of over 12 million people, with projected design values above the 

level of the 24-hour standard of 35 μg/m3. Since the Tier 3 standards go into effect 
Page 84 of 529

during the period when some areas are still working to attain the 2006 and 2012 PM2.5

NAAQS, the projected air quality changes will be useful to state and local agencies in 

their effort to attain and maintain the PM2.5 standards. 

The Tier 3 standards will reduce 24-hour and annual PM2.5 design values due to 

projected tailpipe reductions in primary PM2.5, SO2, NOX and VOCs from reductions in 

fuel sulfur and engine controls. In 2018 the standards will have a small impact on annual 

PM2.5 design values in the majority of modeled counties. However, in over 200 counties 

annual PM2.5 design values are projected to decrease by greater than 0.01 μg/m

3

. In 2030 

annual PM2.5 design values in the majority of modeled counties will decrease by between 

0.01 and 0.05 μg/m3 and in over 140 additional counties design values are projected to 

decrease by greater than 0.05 μg/m3. In addition, in 2018 24-hour PM2.5 design values in 

over 200 counties are projected to decrease by between 0.05 and 0.15 μg/m

3

and in 2030 

24-hour PM2.5 design values in over 180 counties decrease by at least 0.15 μg/m3. 

3. Nitrogen Dioxide

Although our modeling indicates that by 2030 the majority of the country will 

experience decreases of less than 0.1 ppb in their annual NO2 concentrations due to this 

rule, annual NO2 concentrations are projected to decrease by more than 0.3 ppb in most 

urban areas. These emissions reductions would also likely decrease 1-hour NO2

concentrations and help any potential nonattainment areas to attain and maintain the 

standard. Additional information on the emissions reductions that are projected with this 

rule is available in Section 7.2.1 of the RIA. 

4. Air Toxics

Our modeling indicates that the impacts of final Tier 3 standards include notable 

nationwide reductions in benzene and generally small decreases in ambient 

concentrations of other air toxics, mainly in urban areas. Although reductions are greater 

in 2030 (when 70 percent of the miles travelled are from vehicles that meet the fully

phased-in Tier 3 standards) than in 2017 (the first year of the final program), our 

modeling projects there will be small immediate reductions in ambient concentrations of 

air toxics due to the Tier 3 sulfur controls. Furthermore, the full reduction of the vehicle 

program will be realized after 2030, when the fleet has fully turned over to vehicles

meeting the fully phased-in Tier 3 standards. Air toxics pollutants dominated by primary

emissions (or a decay product of a directly emitted pollutant), such as benzene, are 

impacted more than air toxics that primarily result from photochemical transformation. 

Specifically, in 2030, our modeling projects that the Tier 3 rule will decrease 

ambient benzene concentrations across much of the country on the order of 1 to 5 

percent, with reductions ranging from 10 to 25 percent in some urban areas. Our 

modeling also shows reductions of 1,3-butadiene and acrolein concentrations in 2030 

ranging between 1 and 25 percent and 1 and 10 percent respectively, with 1,3-butadiene 

decreases of at least 0.005 μg/m3 in urban areas. These toxics are national risk drivers 
Page 85 of 529

and the reductions in ambient concentrations from this rule will result in reductions in 

risks from cancer and noncancer health effects. In some parts of the country (mainly

urban areas), ethanol and formaldehyde concentrations are projected to decrease on the 

order of 1 to 10 percent and 1 to 2.5 percent respectively in 2030 as a result of the Tier 3 

rule. Decreases in ethanol concentrations are expected due to reductions in VOC as a 

result of the Tier 3 standards. Changes in ambient acetaldehyde concentrations are 

generally less than 1 percent across the U.S., although the Tier 3 rule may decrease 

acetaldehyde concentrations in some urban areas by 1 to 2.5 percent in 2030. Changes in 

ambient naphthalene concentrations are generally between 1 and 10 percent in 2030 with 

absolute decreases of up to 0.005 μg/m3. 

Although the reductions in ambient air toxics concentrations expected from the 

Tier 3 standards are generally small, they are projected to benefit the majority of the U.S. 

population. As shown in Table III-8, over 75 percent of the total U.S. population is 

projected to experience a decrease in ambient benzene and 1,3-butadiene concentrations 

of at least 1 percent. Over 60 percent of the U.S population is projected to experience at 

least a 1 percent decrease in ambient ethanol and acrolein concentrations, and over 35

percent would experience a similar decrease in ambient formaldehyde concentrations 

with the Tier 3 standards. 

Table III-8 Percent of Total Population Experiencing Changes in Annual Ambient 

Concentrations of Toxic Pollutants in 2030 as a Result of the Tier 3 Standards

Percent Change Benzene Acrolein 1,3-Butadiene Formaldehyde Ethanol Acetaldehyde Naphthalene

≤ -50

> -50 to ≤ -25

> -25 to ≤ -10 2.29% 0.75% 19.07% 10.74%

> -10 to ≤ -5 20.63% 12.72% 27.29% 5.39% 31.56%

> -5 to ≤ -2.5 27.50% 25.17% 15.37% 0.60% 24.08% 20.58%

> -2.5 to ≤ -1 28.60% 24.62% 18.33% 35.34% 34.10% 11.77% 14.98%

> -1 to < 1 20.97% 36.74% 19.93% 64.06% 36.43% 88.23% 22.14%

≥ 1 to < 2.5

≥ 2.5 to < 5

≥ 5 to < 10

≥ 10 to < 25

≥ 25 to < 50

≥ 50 

In addition, as described in Section 7.2.4.4.2 of the RIA, our modeling projects 

that acrolein concentrations would decrease to levels below the inhalation reference 

concentration for acrolein (0.02 μg/m3) for over 5 million people in 2030, meaning that as 
Page 86 of 529

a result of the Tier 3 standards, 5 million fewer Americans will be exposed to ambient 

levels of acrolein high enough to present a potential for adverse health effects. 

5. Visibility

Air quality modeling conducted for this final action was used to project visibility

conditions in 137 mandatory class I federal areas across the U.S. The results show that in 

2030 all the modeled areas will continue to have annual average deciview levels above 

background and the Tier 3 rule will improve visibility in all these areas.227 The average 

visibility at all modeled mandatory class I federal areas on the 20 percent worst days is 

projected to improve by 0.02 deciviews, or 0.16 percent, in 2030. Section 7.2.5.5 of the 

RIA contains more detail on the visibility portion of the air quality modeling.

6. Nitrogen and Sulfur Deposition

Our air quality modeling projects substantial decreases in nitrogen deposition as a 

result of the Tier 3 standards. The standards will result in annual percent decreases of 

greater than 2.5 percent in most major urban areas and greater than 5 percent in a few 

areas. In addition, smaller decreases, in the 1 to 2.5 percent range, will occur over much

of the rest of the country. The impacts of the Tier 3 standards on sulfur deposition are 

smaller, ranging from no change to decreases of over 2.5 percent in some areas. For 

maps of 2030 deposition impacts and additional information on these impacts see Section 

7.2.5.6 of the RIA. 

7. Environmental Justice

Environmental justice (EJ) is a principle asserting that all people deserve fair 

treatment and meaningful involvement with respect to environmental laws, regulations, 

and policies. EPA seeks to provide the same degree of protection from environmental 

health hazards for all people. As referenced below, numerous studies have found that 

some environmental hazards are more prevalent in areas with high population fractions 

of racial/ethnic minorities and people with low socioeconomic status (SES), as would be 

expected on the basis of those areas’ share of the general population.

As discussed in Section II of this document, concentrations of many air pollutants 

are elevated near high-traffic roadways. If minority populations and low-income 

 

227 The level of visibility impairment in an area is based on the light-extinction coefficient and a unitless 

visibility index, called a “deciview,” which is used in the valuation of visibility. The deciview metric 

provides a scale for perceived visual changes over the entire range of conditions, from clear to hazy. Under 

many scenic conditions, the average person can generally perceive a change of one deciview. The higher 

the deciview value, the worse the visibility. Thus, an improvement in visibility is a decrease in deciview 

value.
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populations disproportionately live near such roads, then an issue of EJ may be present. 

Such disparities may be due to multiple factors.228

People with low SES often live in neighborhoods with multiple stressors and 

health risk factors, including reduced health insurance coverage rates, higher smoking 

and drug use rates, limited access to fresh food, visible neighborhood violence, and 

elevated rates of obesity and some diseases such as asthma, diabetes, and ischemic heart 

disease. Although questions remain, several studies find stronger associations between 

air pollution and health in locations with such chronic neighborhood stress, suggesting 

that populations in these areas may be more susceptible to the effects of air 

pollution.229,230,231,232 Household-level stressors such as parental smoking and 

relationship stress also may increase susceptibility to the adverse effects of air 

pollution.233,234

To address the existing conditions in areas near major roadways, in comparison 

with other locations, we reviewed existing scholarly literature examining the topic, and 

conducted our own evaluation of two national datasets: the U.S. Census Bureau’s 

American Housing Survey for calendar year 2009 and the U.S. Department of 

Education’s database of school locations.

Existing publications that address EJ issues generally report that populations 

living near major roadways (and other types of transportation infrastructure) tend to be 

composed of larger fractions of nonwhite residents. People living in neighborhoods near 

 

228 Depro, B.; Timmins, C. (2008) Mobility and environmental equity: do housing choices determine 

exposure to air pollution? North Caroline State University Center for Environmental and Resource 

Economic Policy

229 Clougherty, J.E.; Kubzansky, L.D. (2009) A framework for examining social stress and susceptibility to 

air pollution in respiratory health. Environ Health Perspect 117: 1351-1358. Doi:10.1289/ehp.0900612 

[Online at http://dx.doi.org]

230 Clougherty, J.E.; Levy, J.I.; Kubzansky, L.D.; Ryan, P.B.; Franco Suglia, S.; Jacobson Canner, M.; 

Wright, R.J. (2007) Synergistic effects of traffic-related air pollution and exposure to violence on urban 

asthma etiology. Environ Health Perspect 115: 1140-1146. doi:10.1289/ehp.9863 [Online at 

http://dx.doi.org]

231 Finkelstein, M.M.; Jerrett, M.; DeLuca, P.; Finkelstein, N.; Verma, D.K.; Chapman, K.; Sears, M.R. 

(2003) Relation between income, air pollution and mortality: a cohort study. Canadian Med Assn J 169: 

397-402.

232 Shankardass, K.; McConnell, R.; Jerrett, M.; Milam, J.; Richardson, J.; Berhane, K. (2009) Parental 

stress increases the effect of traffic-related air pollution on childhood asthma incidence. Proc Natl Acad 

Sci 106: 12406-12411. doi:10.1073/pnas.0812910106 [Online at http://dx.doi.org]

233 Lewis, A.S.; Sax, S.N.; Wason, S.C.; Campleman, S.L (2011) Non-chemical stressors and cumulative 

risk assessment: an overview of current initiatives and potential air pollutant interactions. Int J Environ 

Res Public Health 8: 2020-2073. Doi:10.3390/ijerph8062020 [Online at http://dx.doi.org]

234 Rosa, M.J.; Jung, K.H.; Perzanowski, M.S.; Kelvin, E.A.; Darling, K.W.; Camann, D.E.; Chillrud, S.N.; 

Whyatt, R.M.; Kinney, P.L.; Perera, F.P.; Miller, R.L (2010) Prenatal exposure to polycyclic aromatic 

hydrocarbons, environmental tobacco smoke and asthma. Respir Med (In press). 

doi:10.1016/j.rmed.2010.11.022 [Online at http://dx.doi.org]
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such sources of air pollution also tend to be lower in income than people living 

elsewhere. Numerous studies evaluating the demographics and socioeconomic status of 

populations or schools near roadways have found that they include a greater percentage 

of minority residents, as well as lower SES (indicated by variables such as median 

household income). Locations in these studies include Los Angeles, CA; Seattle, WA;

Wayne County, MI; Orange County, FL; and the State of California 235,236,237,238,239,240 

More recently, three publications report nationwide analyses that compare the 

demographic patterns of people who do or do not live near major roadways.241,242,243 All 

three of these studies found that people living near major roadways are more likely to be 

minorities or low in SES. They also found that the outcomes of their analyses varied 

between regions within the U.S. However, only one such study looked at whether such 

conclusions were confounded by living in a location with higher population density and 

how demographics differ between locations nationwide. In general, it found that higher 

density areas have higher proportions of low income and minority residents.

We analyzed two national databases that allowed us to evaluate whether homes 

and schools were located near a major road. One database, the American Housing 

Survey (AHS), includes descriptive statistics of over 70,000 housing units across the 

nation. The study is conducted every two years by the U.S. Census Bureau. We 

analyzed data from the 2009 AHS. The second database we analyzed was the U.S. 

Department of Education’s Common Core of Data, which includes enrollment and 

location information for schools across the U.S.

 

235 Marshall, J.D. (2008) Environmental inequality: air pollution exposures in California’s South Coast Air 

Basin.

236 Su, J.G.; Larson, T.; Gould, T.; Cohen, M.; Buzzelli, M. (2010) Transboundary air pollution and 

environmental justice: Vancouver and Seattle compared. GeoJournal 57: 595-608. doi:10.1007/s10708-

009-9269-6 [Online at http://dx.doi.org]

237 Chakraborty, J.; Zandbergen, P.A. (2007) Children at risk: measuring racial/ethnic disparities in 

potential exposure to air pollution at school and home. J Epidemiol Community Health 61: 1074-1079. 

doi: 10.1136/jech.2006.054130 [Online at http://dx.doi.org]

238 Green, R.S.; Smorodinsky, S.; Kim, J.J.; McLaughlin, R.; Ostro, B. (2003) Proximity of California 

public schools to busy roads. Environ Health Perspect 112: 61-66. doi:10.1289/ehp.6566 

[http://dx.doi.org]

239 Wu, Y; Batterman, S.A. (2006) Proximity of schools in Detroit, Michigan to automobile and truck 

traffic. J Exposure Sci & Environ Epidemiol. doi:10.1038/sj.jes.7500484 [Online at http://dx.doi.org]

240 Su, J.G.; Jerrett, M.; de Nazelle, A.; Wolch, J. (2011) Does exposure to air pollution in urban parks have 

socioeconomic, racial, or ethnic gradients? Environ Res 111: 319-328.

241 Rowangould, G.M. (2013) A census of the US near-roadway population: public health and 

environmental justice considerations. Transportation Research Part D; 59-67.

242 Tian, N.; Xue, J.; Barzyk. T.M. (2013) Evaluating socioeconomic and racial differences in traffic-related 

metrics in the United States using a GIS approach. J Exposure Sci Environ Epidemiol 23: 215-222.

243 Boehmer, T.K.; Foster, S.L.; Henry, J.R.; Woghiren-Akinnifesi, E.L.; Yip, F.Y. (2013) Residential 

proximity to major highways – United States, 2010. Morbidity and Mortality Weekly Report 62(3): 46-50. 
Page 89 of 529

In analyzing the 2009 AHS, we focused on whether or not a housing unit was 

located within 300 feet of “4-or-more lane highway, railroad, or airport.”244 We 

analyzed whether there were differences between houses and householders in such 

locations and those not in them.245 We included other variables, such as land use 

category, region of country, and housing type. We found that homes with a nonwhite 

householder were 22-34 percent more likely to be located within 300 feet of these large 

transportation facilities, while homes with a Hispanic householder were 17-33 percent 

more likely. Households near large transportation facilities were, on average, lower in 

income and educational attainment, more likely to be a rental property and located in an 

urban area.

In examining schools near major roadways, we examined the Common Core of 

Data (CCD) from the U.S. Department of Education, which includes information on all 

public elementary and secondary schools and school districts nationwide.246 To 

determine school proximities to major roadways, we used a geographic information 

system (GIS) to map each school and roadways based on the U.S. Census’s TIGER 

roadway file.247 We found that minority students were overrepresented at schools within 

200 meters of the largest roadways, and that schools within 200 meters of the largest 

roadways also had higher than expected numbers of students eligible for free or reducedprice lunches. For example, Black students represent 21.57 percent of students at 

schools located within 200 meters of a primary road, whereas Black students represent 

16.62 percent of students in all U.S. schools. Hispanic students represent 30.13 percent 

of students at schools located within 200 meters of a primary road, whereas Hispanic 

students represent 21.93 percent of students in all U.S. schools.

Overall, there is substantial evidence that people who live or attend school near 

major roadways are more likely to be of a minority race, Hispanic ethnicity, and/or low 

SES. The emission reductions from this rule will result in widespread air quality

improvements, but the impact on pollution levels in close proximity to roadways will be 

most direct. Thus, this rule is likely to help in mitigating the disparity in racial, ethnic, 

and economically-based exposures.

 

244 This variable primarily represents roadway proximity. According to the Central Intelligence Agency’s 

World Factbook, in 2010, the United States had 6,506,204 km or roadways, 224,792 km of railways, and 

15,079 airports. Highways thus represent the overwhelming majority of transportation facilities described 

by this factor in the AHS.

245 Bailey, C. (2011) Demographic and Social Patterns in Housing Units Near Large Highways and other 

Transportation Sources. Memorandum to docket.

246 http://nces.ed.gov/ccd/

247 Pedde, M.; Bailey, C. (2011) Identification of Schools within 200 Meters of U.S. Primary and 

Secondary Roads. Memorandum to the docket.
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IV. Vehicle Emissions Program

In the 14 years since EPA finalized the Tier 2 Vehicle Program, 

manufacturers of light-duty vehicles have continued to develop a wide range of 

improved technologies capable of reducing emissions, especially exhaust 

hydrocarbons, nitrogen oxides (NOX), and particulate matter (PM), and evaporative 

hydrocarbons. The California LEV II program has been instrumental in the auto 

industry’s continuous technology improvements by requiring year after year 

reductions in fleet average exhaust hydrocarbon levels. In addition, California set 

performance standards that have resulted in the introduction of advanced exhaust 

and evaporative emission controls in partial zero emission vehicles (PZEVs). 

Overall, this progress in vehicle technology has made it possible for manufacturers 

to achieve emission reductions with a number of today’s vehicles that go well 

beyond the requirements of the Tier 2 program. 

Extensive data from existing Tier 2 (and California LEV II) vehicles 

presented in the NPRM and received since the proposal have demonstrated the 

potential for further significant reductions. For exhaust emissions, these 

opportunities include addressing: emissions produced at start-up; emissions under 

high-speed, high-load conditions; the effects of sulfur in gasoline; the effects of 

increased oil consumption; and the effects of age on vehicles and control systems. 

In addition, technologies now exist that have inherently low evaporative emission 

characteristics and demonstrate improved in-use durability. Based on this body of 

data, we are adopting more stringent standards designed to reduce emissions, 

primarily exhaust non-methane organic gases (NMOG), NOX, and PM and 

evaporative hydrocarbon emissions from new vehicles. As discussed in detail 

below and in the final RIA, we have concluded that, in conjunction with the 

reductions in fuel sulfur also required in this action, the new vehicle emissions 

standards are feasible, accounting for costs, across the fleet in the timeframe of the 

program. We believe that simultaneous reductions in fuel sulfur will be a key factor 

in enabling the entire fleet of vehicles subject to Tier 3 to meet the new emission 

standards in-use, throughout the life of the vehicles (see Section IV.A.6 below).

We received a large number and wide range of comments on the proposed 

vehicle emission program, and we have carefully considered all of them. (The 

Summary and Analysis of Comments document addresses the comments received; 

it is located in the docket for this rulemaking and also on EPA’s website at 

www.epa.gov/otaq/tier3.htm.) With very few exceptions, we are finalizing the Tier 

3 vehicle emission program as proposed, including the levels of the new emission

standards and the phase-in schedules. In several cases, as discussed in detail below, 

the comments and/or newer technical information have resulted in adjustments to 

the proposed program, including when the requirements begin, what fuel is used for 

vehicle compliance testing, and what the PM standard level is for testing under 
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aggressive driving conditions. The final Tier 3 vehicle provisions, like the 

proposal, also harmonize closely with California’s LEV III program. 

This section describes in detail the program for reducing tailpipe and 

evaporative emissions from light-duty vehicles (LDVs, or passenger cars), lightduty trucks (LDT1s, 2s, 3s, and 4s), Medium-Duty Passenger Vehicles (MDPVs), 

and certain heavy-duty vehicles (HDVs). Sections IV.A and IV.B discuss the 

tailpipe emission standards and time lines, and other provisions for new LDVs, 

LDTs, and MDPVs and for new heavy-duty vehicles up to 14,000 lbs Gross Vehicle 

Weight Rating (GVWR). Section IV.C presents the new Tier 3 evaporative 

emissions standards and program and Section IV.D describes the new evaporative 

emissions leak test. Section IV.E presents improvements to the existing Onboard 

Diagnostics (OBD) provisions. In Section IV.F, we describe new provisions to 

update our federal certification fuel to better match today’s in-use fuel. We also 

discuss in this section the compliance flexibilities for small auto manufacturing 

companies and small-volume manufacturers (IV.G) as well as new testing and test 

procedure provisions and other compliance provisions (IV.H).

A. Tier 3 Tailpipe Emission Standards for Light-Duty Vehicles, Light-Duty 

Trucks, and Medium-Duty Passenger Vehicles

1. How the Tier 3 Program is Harmonized with the California LEV III 

Program

In describing the Tier 3 program for light- and heavy-duty vehicles in this 

preamble, we discuss how the provisions are consistent with the California Air 

Resources Board (CARB) LEV III program.248 During the development of the 

proposed rule and in their comments, auto manufacturers stressed to us the 

importance of their being able to design and produce a single fleet of vehicles for all 

50 states that simultaneously complies with requirements under the Tier 3 program 

and the LEV III program, as well as greenhouse gas/CAFE requirements they are 

facing in the same timeframe. To the extent that the federal and California 

programs are consistent, special versions of vehicles with different emission control 

hardware and calibrations for different geographic areas will be unnecessary. This 

will allow manufacturers to avoid the additional costs of parallel design, 

development, calibration, and manufacturing. Consistency among programs also 

eliminates the need to supply aftermarket parts for repair of multiple versions of a 

vehicle. We believe that the most effective and efficient national program will 

 

248 See California Low-Emission Vehicles (LEV) & GHG 2012 regulations adopted by the State of 

California Air Resources Board, March 22, 2012, Resolution 12-21 incorporating by reference 

Resolution 12-11, which was adopted January 26, 2012. Available at 

http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm (last accessed December 2, 

2013).
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result from close coordination between CARB LEV III and federal Tier 3 program 

elements and their implementation. 

To that end, we worked closely with CARB and the vehicle manufacturers, 

the latter both individually and through their trade associations, to align the two 

programs. The Tier 3 program is identical to LEV III in most major respects for 

light-duty vehicles (and heavy-duty vehicles, as described in sections below). The 

levels and the timing of the declining fleet-average NMOG+NOX standards are

identical to those in LEV III. The Tier 3 emissions bins to which manufacturers 

will certify individual vehicle models in order to comply with the fleet-average 

standards, are also identical to those in LEV III. Similarly, the light-duty Tier 3 

FTP PM standards and percent phase-in match those for LEV III through MY 2024. 

We note there are a few light-duty Tier 3 and LEV III provisions that are

different, for reasons discussed below. For example, the LEV III program and the

Tier 3 program have different light-duty PM requirements late in the program (i.e., 

after MY 2024 (IV.A.3.b.)), and the two programs have different final 

NMOG+NOX standards for small volume manufacturers (IV.G.1). As also 

discussed below, we are finalizing a revised SFTP (US06) PM standard, and CARB 

has commented that it plans to take similar action in near future. CARB also 

indicated in their comments that they intend to consider several additional actions to 

further align several minor aspects of LEV III with the Tier 3 program once Tier 3 

is finalized. 

Beyond the provisions mentioned above, the differences between the 

programs are not major and most will exist only in the transitional years of the Tier 

3 program. These additional differences result from the fact that the LEV III 

requirements begin slightly earlier and that a limited phase-in of some provisions is

necessary for a smooth transition to overall aligned programs. These temporary

differences include the process for how early compliance credits are generated and 

used (e.g., Section IV.A.7.a); how quickly manufacturers will need to move toward 

certifying all of their vehicle models to longer useful-life values (e.g., Section 

IV.A.7.c) and on the new test fuel (e.g., Section IV.A.7.d); and transitional 

emissions bins to facilitate the transition from Tier 2 to Tier 3 (Section IV.A.7.n). 

2. Summary of the Tier 3 FTP and SFTP Tailpipe Standards

a. Major Comments on and Significant Changes to the Proposal

As mentioned above, we are finalizing most aspects of the comprehensive 

Tier 3 vehicle program as we proposed them. The levels of the FTP and SFTP 

standards for the key tailpipe pollutants of concern -- the sum of NMOG and NOX

emissions, expressed as NMOG+NOX, and PM -- are the same as proposed (except 

for the numerically lower final PM SFTP (US06) standard, as discussed below). In 

addition, the timing of the requirements remains the same as in the NPRM, starting 
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with MY2017 and MY2018 and phasing in according to the same declining fleetaverage schedule for the NMOG+NOX standards and the same percent-of-sales 

phase-in schedule for the PM standards. We continue to believe that these elements 

form a robust framework for the Tier 3 vehicle program and closely harmonize with 

the respective elements of California’s LEV III program.

There are several important provisions of the light-duty Tier 3 program that 

we have revised from the proposal, based on further consideration and information 

that we received from commenters. We discuss each of these in detail later in this 

section and summarize them here. 

 As described below in Section IV.A.2.c, each of the four primary Tier 3 

emission standards has an associated alternative phase-in option for 

heavier light-duty vehicles that a manufacturer can choose if it prefers a 

later start date (to provide 4 years of lead time) and a stable standard.249 

We proposed that a manufacturer choosing these options be required to 

apply the alternative phase-in schedule to its entire light-duty fleet. In 

response to comments from automakers that this restriction would be 

unnecessarily burdensome, we reconsidered this provision. For the 

reasons discussed below, we are allowing a manufacturer to apply the 

alternative phase-in schedules to only their heavier light-duty vehicles, 

instead of their entire light-duty fleet. However, manufacturers have 

largely indicated that they plan on adopting the primary program which 

is harmonized with LEV III.

 This Tier 3 rule provides an opportunity for EPA to reassess the degree 

to which the gasoline used for vehicle emissions testing and certification 

reflects in-use gasoline around the country. In the case of ethanol 

content, we proposed that the emissions test fuel contain 15 percent 

ethanol (E15), anticipating a significant shift to higher ethanol content in 

use in the near future. For several reasons described below (Section 

IV.F.1), this shift in in-use fuel is not materializing as quickly as 

expected, and E10 continues to be almost universal today. We received 

a near consensus among comments from stakeholders that E10 test fuel 

is more appropriate. We agree that E10 most appropriately reflects inuse gasoline around the country today and into the foreseeable future, 

and thus we are finalizing E10 for the test fuel. In addition, as discussed 

in Section IV.F.1, we are finalizing a fuel volatility specification for test 

fuel of 9 psi RVP, as proposed.

 

249 In this preamble, “heavier light-duty vehicles” refers to LDVs and LDTs greater than 6,000 lbs 

GVWR and MDPVs, and “lighter light-duty vehicles” refers to LDVs and LDTs up to 6,000 lbs 

GVWR.
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 We are finalizing a set of standards for PM as measured on the 

aggressive-driving segment of the SFTP test cycle (the US06 cycle) 

based on US06 PM test data that we published as part of the NPRM, 

along with more recent test data developed by California. Our review of 

these data has led us to finalize numerically lower levels for the US06 

PM standards than we proposed. The data presented in the NPRM as 

well as the data provided by California clearly show that the proposed 

US06 PM standards were inappropriately high, that US06 PM emissions 

are not closely related to vehicle weight, and that lower values for the 

standards would achieve the goal of the program to bring all vehicles in 

the light-duty fleet to the US06 PM levels that are being met by many 

vehicles today. Based on the body of available data, we are establishing 

6 mg/mi as the long-term US06 PM standard. (This compares to the 

proposed standards of 10 and 20 mg/mi for lighter and heavier light-duty 

vehicles, respectively.) However, because there remains some 

uncertainty about how manufacturers will achieve this level in the early 

years of the program, we are setting the standard at 10 mg/mi for the 

early years of the program, for MYs 2017 and 2018. Similarly, we are 

providing a less-stringent standard of 10 mg/mi for testing of in-use 

vehicles in recognition of the challenges of the requirements as vehicles 

age. 

 In the Tier 3 program, as for vehicle emission control programs in the 

past, manufacturers are responsible for the emissions performance of the 

vehicle for a specified “useful life” of the vehicle. EPA proposed that 

vehicles meet the Tier 3 standards for 150,000 miles or 15 years, 

identical to the LEV III program’s approach. We proposed an option for 

lighter light-duty vehicles to certify to a shorter useful life of 120,000 

miles or 10 (or 11, as applicable) years, as set in the Tier 2 program. We

proposed that manufacturers certifying to the shorter useful life would 

need to meet numerically lower NMOG+NOX standards (85 percent of 

the respective 150,000-mile NMOG+NOX standards). We also proposed 

that a manufacturer choosing the shorter useful life for one vehicle 

model would need to use that useful life and associated standards for all 

of its lighter vehicles. Auto industry commenters stated that applying 

the provision across a manufacturer’s fleet would create an onerous 

compliance burden. We have reconsidered our proposed approach, and 

as discussed in Section IV.A.7.c below, we will allow a manufacturer to 

split its lighter light-duty fleet among models certified for either the 

150,000 mile or 120,000 mile useful life and associated standards. 

 Another area of substantial comment, primarily from the petroleum 

refining industry, questioned the technological need of auto 

manufacturers for lower in-use sulfur levels in order to meet the Tier 3 
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vehicle emission standards. In contrast, auto manufacturers and 

emissions control system manufacturers commented that lower sulfur 

gasoline is critical to meet the Tier 3 standards. After careful 

consideration of the comments, we continue to believe that the large 

body of data presented in the NPRM, supplemented by newer data that 

consistently reinforces the earlier conclusions, strongly supports our 

determination of the need for average in-use gasoline sulfur levels to be 

at 10 ppm sulfur or lower for manufacturers to meet the Tier 3 vehicle 

standards across their fleets for the useful life of the vehicles. See 

Section IV.A.6 below for a detailed discussion of the need for gasoline 

sulfur control. 

b. Structure of the Primary Tier 3 Tailpipe Standards

As proposed, compliance with the standards is based on vehicle testing 

using test procedures that represent a range of vehicle operation, including the 

Federal Test Procedure (FTP) and the Supplemental Federal Test Procedure 

(SFTP). The Tier 3 FTP and SFTP NMOG+NOX standards are fleet-average 

standards, meaning that the manufacturer calculates the sales-weighted average 

emissions of the vehicles it sells in each model year, accounting for any Tier 3 

emissions credits or deficits, and compares that average to the applicable standard 

for that model year. The fleet average standards for NMOG+NOX evaluated over 

the FTP are the same values as proposed and are summarized in Table IV-2 and 

discussed in detail below. For lighter light-duty vehicles, the standards begin in MY

2017 at a level representing a 46 percent reduction from the current Tier 2 

requirements for lighter vehicles and then become increasingly stringent, 

culminating in an 81 percent reduction in MY 2025. The FTP NMOG+NOX

program includes separate fleet average standards for heavier vehicles that begin in 

MY 2018 and then converge with the standards for lighter vehicles at 30 milligrams 

per mile (mg/mi) in MY 2025 and later, as proposed.

250,251

Manufacturers will determine their fleet average FTP NMOG+NOX

emission values as we proposed, based on the per-vehicle “bin standards” to which 

they certify each vehicle model. Manufacturers will be free to certify vehicles to 

any of the bins, so long as the sales-weighted average of the NMOG+NOX values 

from the selected bins meets the fleet average standard for that model year. Table 

IV-1 presents the per-vehicle bin standards. Similarly, the fleet average 

 

250 The declining NMOG+NOX fleet-average standards consist of one set of declining standards that 

applies to light-duty vehicles (LDVs) and small light trucks (LDT1s) and a second set of declining 

standards that applies to heavier light trucks (LDT2s, LDT3s. LDT4s), and MDPVs.

251 This preamble presents the new Tier 3 standards in terms of milligrams per mile (mg/mi) for 

convenience. Throughout the associated Tier 3 regulatory language we continue to present the 

standards in terms of grams per mile (g/mi) for consistency with earlier programs. 
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NMOG+NOX standards measured over the SFTP are summarized in Table IV-4 and 

discussed in detail below. The SFTP NMOG+NOX fleet average standards decline 

from MY 2017 until MY 2025. In this case, the same standards apply to both 

lighter and heavier vehicles. In MY 2025, the SFTP NMOG+NOX standard reaches

its fully phased-in fleet average level of 50 mg/mi. 

Also as proposed, the new Tier 3 PM standards apply to each vehicle 

separately. The PM standards are per-vehicle cap standards and not fleet-average

standards. Also, in contrast to the declining NMOG+NOX standards, the PM 

standard on the FTP is a constant 3 mg/mi for all vehicles and for all model years, 

phasing in to an increasing percentage of vehicle sales beginning in MY 2017 for 

vehicles at or below 6,000 lbs Gross Vehicle Weight Rating (GVWR) and in MY 

2018 for vehicles above 6,000 lbs GVWR. As discussed in Section IV.A.3.b above, 

based on data generated by EPA and CARB test programs, most current light-duty

vehicles are already performing at or below the 3 mg/mi level. However, some 

vehicles are emitting above this level, due to such factors as excessive fueling 

during cold start and combustion chamber and fuel system designs that are not 

optimized for low PM emissions. The intent of the 3 mg/mi standard is to bring all 

light-duty vehicles to the PM level typical of that being demonstrated by most lightduty vehicles today. To address the uncertainties that will accompany the 

introduction of new technologies, the program includes a separate in-use FTP PM 

standard of 6 mg/mi for the testing of in-use vehicles during the phase-in period, as 

proposed, as described in more detail below. 

As presented in Table IV-3, for vehicles at or below 6000 lbs GVWR, these 

FTP PM certification and in-use standards phase in over several years, beginning 

with a requirement that at least 20 percent of a company’s U.S. sales of these 

vehicles comply with the Tier 3 standards in MY 2017. We are also finalizing an 

option for a manufacturer to choose to certify 10 percent of its total light-duty fleet 

sales – including LDVs and LDT over 6,000 lbs GVWR and MDPVs – to the Tier 3 

FTP PM standards in MY 2017. Manufacturers would reach a 100 percent 

compliance requirement in MY 2021. 

Finally, the Tier 3 program includes PM standards evaluated over the US06 

cycle (a component of the SFTP test that captures higher speeds and accelerations). 

Based on emissions test data presented in the NPRM and additional data submitted 

in public comments, and as presented in Table IV-5 and further discussed in Section 

IV.A.4.b below, we are establishing a single long-term US06 PM standard of 6 

mg/mi for both lighter and heavier vehicles, a level that is numerically lower than 

what we proposed. However, because there remains some uncertainty about how 

manufacturers will decide to achieve this level in the early years of the program, we 

are setting the standard through MY 2018 at 10 mg/mi. The US06 PM standards 

phase in using the same 20-20-40-70-100 percent schedule, and on the same 

vehicles, as the new FTP PM standards. The 10 mg/mi standard applies in MYs 

2017 and 2018 (at a percent-of-sales requirement of 20 percent, and the long-term 6 
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mg/mi standard applies in MYs 2019 and later, increasing from 40 to 100 percent of 

sales. This US06 standard will apply to the same vehicle models that a 

manufacturer chooses to certify to the FTP PM standard during the percent phase-in 

period. As in the case of the FTP PM standards, the intent of the standard is to 

bring the emission performance of all vehicles to that already being demonstrated 

by many vehicles in the current light-duty fleet. As proposed, we include a separate 

in-use US06 PM standard during in the middle years of the program, but at a 

different numerical level and during different years than proposed (as discussed in 

Section IV.A.4.b below). 

We did not propose new emission requirements for any vehicle or fuel over 

the cold temperature test cycles (i.e., the 20 °F cold carbon monoxide (CO) and 

non-methane hydrocarbon (NMHC) tests), but requested comment on that decision. 

Only the automakers commented on this topic, agreeing with EPA’s approach of 

not changing its cold temperature requirements. As indicated in the proposal, we 

are not establishing any new cold temperature requirements in this rule.

c. Alternate Phase-In Schedules

For heavier light-duty vehicles (i.e., LDVs and LDTs greater than 6,000 lbs 

GVWR, plus MDPVs), EPA is also finalizing alternative phase-in schedules for 

each of the four primary vehicle emission standards: FTP NMOG+NOX, FTP PM, 

SFTP NMOG+NOX, and US06 PM.252 These alternative phase-ins are available if 

a manufacturer prefers stable standards and four full years of lead time, as specified 

in the Clean Air Act for heavier vehicles. We describe each of the alternative 

phase-ins in more detail below, including several ways in which we have revised 

the proposed provisions. 

EPA received comment on the proposed alternative phase-in provisions, 

primarily from automakers and their trade associations. These comments 

questioned whether the proposed structure of and restrictions on the use of the 

alternative phase-ins were so onerous as to unduly restrict a manufacturer from 

choosing the alternative phase-ins and their lead time and stability provisions as set 

forth in the Clean Air Act. The commenters criticized the proposed requirement 

that a manufacturer using the alternative phase-ins apply the alternative schedules to 

its entire light-duty fleet, both below and above 6,000 lbs GVWR. EPA had 

proposed this provision to minimize the complexity of complying with the 

alternative phase-in if a manufacturer’s heavier and lighter light-duty vehicles had 

different compliance structures. 

 

252 Tier 3 standards for CO and HCHO phase in with the NMOG+NOx standards, as applicable.
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In consideration of these concerns, we have removed from the alternative 

phase-in provisions the requirement that a manufacturer apply the alternative 

schedules to its entire light-duty fleet including vehicles below 6,000 lbs GVWR. 

For the practical functioning of the program, the final rule requires that any 

manufacturer choosing to use the alternative phase-in apply all four alternative 

phase-in schedules to its entire light-duty fleet above 6,000 lbs GVWR. We believe 

that the alternative phase-ins allow manufacturers to comply with emission 

standards in a time frame that is clearly feasible and fully compliant with the CAA 

requirements for lead time and regulatory stability. To the extent that 

manufacturers choose to use them, the alternative would result in overall emission 

reductions essentially identical to those of the primary program. 

The alternative phase-in schedules would begin to apply to each vehicle for 

either MY 2019 or MY 2020, depending on exactly when the manufacturer begins 

production of the vehicle. (See Section 86.1811-17(b)(8)(i) for how we implement 

this provision.) For models that begin MY 2019 production after the fourth 

anniversary of the signing of this final rule, the alternative phase-in would provide 

four full years of lead time and would first apply for MY 2019. The phase-in 

obligation would be calculated based only on those vehicles beginning production 

after the fourth anniversary date. For models beginning production before that date, 

the alternative phase-in would first apply for MY 2020, and the phase-in percentage 

for MY 2020 would be based on the manufacturer’s entire fleet of heavier lightduty vehicles. Based on historical certification patterns, few models begin 

production before mid-calendar-year, so we expect that the vast majority of MY 

2019 vehicles will begin production after the 4-year anniversary and thus the 

alternative phase-ins, if chosen, will typically apply beginning in MY 2019. 

At the time of certification for MY 2018, a manufacturer must declare 

whether it intends to apply the alternative phase-in schedules to its heavier lightduty vehicles. A manufacturer choosing the alternative phase-ins would be 

committed to this phase-in approach for the duration of the phase-ins, and could not 

later choose the fleet-average approach for NMOG+ NOX standards. For all 

vehicles below 6,000 lbs GVWR, the primary program will apply, beginning in MY 

2017. For a manufacture’s vehicles subject to the alternative phase-ins, there would 

be no new tailpipe emissions requirements beyond the Tier 2 program until the 

beginning of the alternative phase-in schedules; that is, MY 2019 or 2020, as 

explained above.

As discussed above, a manufacturer choosing the alternative phase-in 

approach for its heavier light-duty vehicles would be required to use all four phaseins together. The next paragraphs explain how each of the alternative phase-ins 

requires an increasing percent of the manufacturer’s sales to comply with the 

alternative standards. Thus, until the end of the phase-ins, some percent of a 

manufacturer’s affected vehicles will meet the new standard and the remainder of 

that year’s sales will not yet comply with Tier 3. For the practical functioning of 
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the program, a manufacturer choosing the alternative phase-ins would be required 

to comply with exactly the same segment of their fleet in each model year for all 

four alternative phase-ins. For example, a manufacturer that complies with the 70 

percent MY 2020 requirement for the FTP NMOG+NOX standard with a segment 

of its vehicle fleet must meet the 70 percent MY 2020 requirement for the FTP PM 

standard with the same set of vehicles. Vehicles covered by the alternative phase-in 

programs would be considered “Final Tier 3” vehicles and thus would also need to 

comply with the Tier 3 certification fuel and full useful life provisions. 

For the FTP and SFTP NMOG+NOX alternative phase-in schedules, once 

the phase-in is complete for a segment of a manufacturer’s fleet, the standards 

continue for that set of vehicles through MY 2024, after which the full Tier 3 

program applies regardless of the phase-in strategy. Thus, the fleet-average 

standards that decline through MY 2024 do not apply for these vehicles. 

Although manufacturers would implement all four alternative phase-in 

schedules together, as discussed above, each alternative phase-in has unique 

characteristics. The following paragraphs explain the unique provisions of each. 

(1) Alternative Phase-In Schedule for the FTP NMOG+NOX Standard

Instead of the primary FTP NMOG+ NOX declining fleet average standards, 

a manufacturer choosing the alternative phase-ins would comply with a stable fleet 

average FTP NMOG+NOX standard of 30 mg/mi that would apply to an increasing 

percentage of a manufacturer’s combined sales of LDVs and LDTs above 6,000 lbs 

GVWR and MDPVs. This percent phase-in would match the percentages in the 

primary PM percent phase-in schedule, as discussed above – specifically, 40 

percent of MY 2019 heavier light-duty vehicles (excluding those vehicles with 

production beginning before the 4-year anniversary), 70 percent of all of its heavier 

light-duty vehicles in MY 2020, and 100 percent compliance in MY 2021 and later 

model years. 

(2) Alternative Phase-In Schedule for the FTP PM Standard

Instead of the primary FTP PM percent phase-in schedule, a manufacturer 

choosing the alternative phase-ins would postpone the beginning of its FTP PM 

phase-in for its LDVs and LDTs above 6,000 lbs GVWR and MDPVs until MY 

2019 or 2020 (depending on the dates production begins for its vehicle models, as 

discussed above). The manufacturer would then comply with the 3 mg/mi pervehicle FTP PM standard (and the 6 mg/mi in-use standard) on an increasing 

percentage of these vehicles, following the 40-70-100 percentage phase-in of the 

primary PM program -- specifically, 40 percent of MY 2019 heavier light-duty

vehicles (excluding those vehicles with production beginning before the 4-year 

anniversary), 70 percent of all of its heavier light-duty vehicles in MY 2020, and 

100 percent compliance in MY 2021 and later model years. 
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(3) Alternative Phase-In Schedule for the SFTP NMOG+NOX Standard

As with the other alternative phase-ins, instead of the primary SFTP 

NMOG+ NOX declining fleet average standards, a manufacturer choosing the 

alternative phase-ins would comply with a stable fleet average SFTP NMOG+NOX

standard of 50 mg/mi that would apply to an increasing percentage of a 

manufacturer’s combined sales of LDVs and LDTs above 6000 lbs GVWR and 

MDPVs. This percent phase-in again would match the percentages in the primary

PM percent phase-in schedule, as discussed above – specifically, 40 percent of MY 

2019 heavier light-duty vehicles (excluding those vehicles with production 

beginning before the 4-year anniversary), 70 percent of all of its heavier light-duty 

vehicles in MY 2020, and 100 percent compliance in MY 2021 and later model 

years.

(4) Alternative Phase-In Schedule for the US06 PM Standard

Finally, instead of the primary US06 PM percent phase-in schedule, a 

manufacturer choosing the alternative phase-ins would postpone the beginning of 

the US06 phase-in for its LDVs and LDTs above 6,000 lbs GVWR and MDPVs 

until MY 2019 or 2020 (depending on the dates production begins for its vehicle 

models, as discussed above). The manufacturer would then comply with the 10 

mg/mi US06 PM standard for 40 percent of MY 2019 heavier light-duty vehicles 

(excluding those vehicles with production beginning before the 4-year anniversary), 

70 percent of all of its heavier light-duty vehicles in MY 2020, with 100 percent 

compliance in MY 2021, and then 100 percent compliance with the 6 mg/mi 

standard in MY 2022 and later model years.

The next sections describe in more detail the new Tier 3 standards, how they

will be implemented over time, and the technological approaches that we believe 

are or will be available to manufacturers in order to comply.

3. FTP Standards

As summarized above, we are finalizing, largely as proposed, new standards 

for the primary pollutants of concern for this rule (NMOG, NOX, and PM) as 

measured on the FTP. The following paragraphs describe in more detail these FTP 

standards for NMOG+NOX and PM, as well as for carbon monoxide (CO) and 

formaldehyde (HCHO). 
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a. FTP NMOG+NOX Standards

The Tier 3 NMOG and NOX standards are expressed in terms of the sum of 

the two pollutants -- NMOG+NOX in mg/mi.253 We received no comments 

recommending a different approach. The California LEV III standards are also 

expressed as NMOG+NOX; aligning Tier 3 with LEV III is an important element of 

facilitating a national program.

EPA received a number of comments about how the proposed NMOG+

NOX standards transition from the existing Tier 2 standards, but there was little 

comment recommending different levels of the standards themselves, especially

later in the program. Based on our extensive evaluation of existing and emerging 

vehicle technologies (see Section IV.A.5) and the level of sulfur in gasoline that 

will be available during the implementation timeframe of this rule, and considering 

the comments we received, we continue to believe that the fully phased-in level for 

the fleet-average FTP NMOG+NOx standard of 30 mg/mi is the most stringent 

level that we can reasonably establish. As discussed in Sections IV.A.5 and IV.A.6 

below, when necessary margins of compliance and the demonstrated effects of fuel 

sulfur on emissions performance are considered, the 30 mg/mi standard is 

effectively very close to zero. The 30 mg/mi Tier 3 NMOG+NOX standard is also 

consistent with the final LEV III standard.

A key compliance mechanism adapted from the Tier 2 program is a “bin” 

structure for the FTP emission standards. For these purposes, a bin is a set of 

several standards that must be complied with as a group. Thus, as proposed, each 

FTP Tier 3 bin has an NMOG+NOX standard and a PM standard, as well as CO and 

HCHO standards. 

We intend for the Tier 3 CO and HCHO standards to prevent new engine 

and emission control designs that result in increases in CO and HCHO emissions, 

compared to levels being achieved today. The standards are based on the 

comparable current LEV II and Tier 2 bin standards for these pollutants, which we 

believe are sufficiently protective at this time. There were no comments on the 

proposed CO and HCHO standards. The current standards are not technologyforcing, and we believe that this will continue to be the case as Tier 3 technologies 

are developed.

 

253 See California Low-Emission Vehicles (LEV) & GHG 2012 regulations adopted by the State of 

California Air Resources Board, March 22, 2012, Resolution 12-21 incorporating by reference 

Resolution 12-11, which was adopted January 26, 2012. Available at 

http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm (last accessed December 2, 

2013).
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Table IV-1 presents the bin structure for light-duty vehicle, light-duty truck, 

and MDPV FTP standards.

Table IV-1 Tier 3 FTP Standards for LDVs, LDTs and MDPVs (mg/mi)

Bin NMOG+ NOX

(mg/mi)

PMa

(mg/mi)

CO

(g/mi)

HCHO

(mg/mi)

Bin 160 160 3 4.2 4

Bin 125 125 3 2.1 4

Bin 70 70 3 1.7 4

Bin 50 50 3 1.7 4

Bin 30 30 3 1.0 4

Bin 20 20 3 1.0 4

Bin 0 0 0 0 0

a

 In MYs 2017-20, the PM standard applies only to that segment of a manufacturer’s vehicles 

covered by the percent of sales phase-in for that model year. 

Consistent with the Tier 2 principle of vehicle and fuel neutrality, the same 

Tier 3 standards apply to all LDVs, LDTs, or MDPVs, regardless of the fuel they 

use, as proposed. That is, vehicles certified to operate on any fuel (e.g., gasoline, 

diesel fuel, E85, CNG, LNG, hydrogen, and methanol) are all subject to the same 

standards. 

The Tier 3 NMOG+NOX standards as measured on the FTP will reduce the 

combined fleet-average emissions gradually from MY 2017 through 2025, as shown 

in Table IV-2 below. Beginning in MY 2017, there are two separate sets of fleetaverage standards for, first, LDVs and LDT1s and, second, all other LDTs (LDT2s, 

LDT3s, and LDT4s) and MDPVs. Both fleet-average standards decline annually, 

converging in MY 2025. These declining average standards are identical to 

CARB’s LEV III standards.254

As proposed and as discussed above (Section IV.A.2.a), the declining fleetaverage NMOG+NOX FTP standards begin in MY 2017 for light-duty vehicles and 

light-duty trucks with a GVWR up to and including 6,000 lbs and in MY 2018 for 

light-duty vehicles and light-duty trucks with a GVWR greater than 6,000 lbs and 

MDPVs. The standards apply to the heavier vehicles a year later to facilitate the 

transition to a 50-state program for all manufacturers. During this transition period, 

 

254 See California Low-Emission Vehicles (LEV) & GHG 2012 regulations adopted by the State of 

California Air Resources Board, March 22, 2012, Resolution 12-21 incorporating by reference 

Resolution 12-11, which was adopted January 26, 2012. Available at 

http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm (last accessed January 14, 

2014).
Page 103 of 529

as described above, there will be two fleet-average NMOG+NOX standards for each 

model year, one for LDVs and LDT1s and one for all other LDTs (LDT2s, LDT3s, 

and LDT4s) and for MDPVs that decline essentially linearly from MY 2017 

through MY 2025. At that point, the two fleet-average standards converge and 

stabilize for all later model years at the same level, 30 mg/mi, as shown in Table 

IV-2. 

Table IV-2 Tier 3 LDV, LDT, and MDPV Fleet Average FTP NMOG+NOX

Standards (mg/mi) 

Model Year

2017a2018 2019 2020 2021 2022 2023 2024 2025 

and later

LDV/LDT1b86 79 72 65 58 51 44 37

LDT2,3,4 and 30

MDPV

101 92 83 74 65 56 47 38

a

For LDVs and LDTs over 6,000 lbs GVWR and MDPVs, the fleet average standards apply

beginning in MY 2018.

b These standards apply for a 150,000 mile useful life. Manufacturers can choose to certify their 

LDVs and LDV1s to a useful life of 120,000 miles. If a vehicle model is certified to the shorter 

useful life, a proportionally lower numerical fleet average standard applies, calculated by 

multiplying the respective 150,000 mile standard by 0.85 and rounding to the nearest mg/mi. See 

Section IV.A.7.c.

As discussed above (Section IV.A.2.c), for LDVs and LDTs above 6,000 lbs 

GVWR and MDPVs, EPA is also providing an alternative phase-in of the fleetaverage 30 mg/mi FTP NMOG+NOX standard. 

b. FTP PM Standards

We are establishing new FTP standards for PM emissions at the proposed 

levels -- 3 mg/mi, with a temporary standard of 6 mg/mi for in-use vehicle testing --

as summarized in Table IV-3 below. These levels are intended to ensure that all 

new vehicles will perform at a level representing what is already being achieved by 

well-designed emission control technologies today. 

Many commenters were either silent on or supportive of the proposed FTP 

PM standard levels. However, some commenters – including CARB and several 

NGOs and auto industry suppliers -- supported a more stringent standard of 1 

mg/mi, which the California LEV III program phases in beginning in MY 2025. 

After detailed consideration of these comments and information available at this 

time, we continue to believe that the PM standards that we are finalizing for the 

federal Tier 3 program are the most stringent technically feasible standards within 

the implementation timeframe of this rule. (See Section 1.5.1 of the RIA.) We will 
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continue to work closely with CARB in this area. Specifically, our agencies will 

continue our parallel evaluations of how improved gravimetric PM measurement 

methods can reduce PM mass measurement variability at very low PM levels and 

how this relates to the evolving technological capabilities of automakers to reach 

very low PM levels with sufficient compliance margins. 

PM emissions over the FTP are generally attributed to the cold start, when 

PM formation from combustion of the fuel is facilitated by the operating conditions, 

including a cold combustion chamber and fuel enrichment. During cold-start

operation, PM control is less effective, especially the oxidation by the catalytic 

converter of semi-volatile organic compounds from the lubricating oil. We believe 

that for vehicles that are not already at the Tier 3 levels, the new standards can be 

achieved with improvements to the fuel controls during the cold start, without the 

need for any new technology or hardware. We also expect that manufacturers will 

pay close attention to maintaining low PM emissions during the implementation of 

newer technologies like gasoline direct injection (GDI) and turbocharged engines. 

Improvements in cold-start exhaust catalyst performance for NMOG+NOx control 

will also reduce emissions of semi-volatile organic PM. For these reasons, cold 

start PM levels are relatively independent of vehicle application and therefore we 

are finalizing a single FTP PM standard for all light-duty vehicles, as proposed. 

Unlike the NMOG+NOX FTP standard, it is not necessary for the FTP PM 

standard to phase in on a declining curve over time, since most manufacturers are 

already producing vehicles that meet the new standards. We are finalizing the 

proposed PM FTP percent-of-sales phase-in during the first 5 years of the Tier 3 

program in response to concerns expressed by automakers about logistical, 

facilities, and compliance challenges with a standard in the range of 3 mg/mi in the 

early years of the program. Beginning in MY 2017 (and in MY 2018 for LDVs and 

LDTs over 6,000 lbs GVWR and MDPVs), manufacturers will need to comply with 

the PM standard with a minimum of 20 percent of their U.S. sales. As shown in 

Table IV-3, the percentage of the manufacturer’s sales that need to comply 

increases each year, reaching 100 percent in MY 2021. In addition to this percent 

phase-in, we are also establishing, as proposed, a separate PM standard of 6 mg/mi 

that will apply only for in-use testing of vehicles certified to the new standards, and 

only during the percent phase-in period. 

Due to the MY 2018 start date for vehicles over 6,000 lbs GVWR, 

manufacturers that have few or no vehicle models over 6,000 lbs GVWR will be 

required to certify a larger percentage of their total light-duty sales in MY 2017 

than full line manufacturers. While we believe that most manufacturers will likely

choose a single large-volume durability group to meet the 2017 requirements, we 

are also including an option that a manufacturer could use to comply with the MY 

2017 PM requirements. Under this option, a manufacturer may choose to certify 10 

percent of its total light-duty vehicle sales in MY 2017 to the new PM standards, 

including light-duty vehicles over 6,000 lbs. This approach is consistent with the 
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CARB LEV III program, which requires that 10 percent of all light-duty vehicle 

sales meet the new PM standards in MY 2017. 

Because of the expected time and expense of performing emission tests on 

the improved PM test procedures, we are limiting the number of tests using the new 

procedures that a manufacturer needs to perform at certification and during in-use 

testing, as proposed. Specifically, manufacturers will only be required to test 

vehicles representing a minimum of 25 percent of a model’s durability test groups 

during certification each model year (and a minimum of 2 durability groups).255 

Manufacturers may select which durability groups to test, but will need to rotate the 

groups tested each year to eventually cover their whole fleet. Similarly, 

manufacturers performing in-use testing under the In-Use Verification Program can

limit their testing to 50 percent of their low- and high-mileage test vehicles. Again, 

manufacturers will need to rotate their vehicle models so that each model will be 

tested every other year. Overall, we believe that the flexibility that these provisions 

provide will facilitate the expeditious implementation of the Tier 3 program, with 

no significant impact on the benefits of the program.

Table IV-3 Summary of Tier 3 LDV, LDT, and MDPV FTP Standards

Program Element Units

Model Year Notes

2017a2018 2019 2020 2021 2022 2023+

NMOG+NOX

Standard

(fleet average)

mg/mi Per declining fleet averages (see Table IV-2)

b

PM Standards

Phase-in % 20c20 40 70 100 100 100

FTP

Certification mg/mi 3 3 3 3 3 3 3 Note d

In-use mg/mi 6 6 6 6 6 3 3 Note e

a

For LDVs and LDTs above 6,000 lbs GVWR and MDPVs, the FTP PM standards apply beginning 

in MY 2018.

b The percent phase-in does not apply to the declining fleet average standards. 

c Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs 

GVWR, or alternatively with 10 percent of their total LDV, LDT, and MDPV fleet. 

d Manufacturers must test 25 percent of each model year’s durability groups, and a minimum of 2.

e Manufacturers must test 50 percent of their combined low- and high- mileage in-use vehicles. 

 

255 Durability groups are a subset of engine families. Several engine families may have the same 

durability group.
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As discussed in Section IV.A.2.c above, for LDVs and LDTs above 6,000 

lbs GVWR and MDPVs, EPA is providing an alternative phase-in of the 3 mg/mi 

FTP PM standard. 

4. SFTP Standards 

In addition to addressing vehicle emissions during typical driving, as 

addressed by the FTP standards presented above, the Tier 3 program also addresses 

emissions during more severe driving conditions. Thus, we are finalizing

NMOG+NOX and PM standards as measured on the SFTP. The SFTP (and 

specifically the US06 component of the test) is designed to simulate, among other 

conditions, higher speeds and higher acceleration rates, and thus higher loads. As 

described below, most commenters were supportive of or silent on the proposed 

SFTP NMOG+NOX standards and the associated declining fleet-average phase-in 

schedule, but several commenters stated that the level of the standards should be 

more stringent than proposed. Based on our analysis of the stringency of the 

program, discussed in Section IV.A.5 below and in Chapter 1 of the RIA, we 

disagree that more stringent SFTP NMOG+ NOX standards are necessary or 

appropriate at this time, and we are finalizing the standards and phase-in schedule 

as proposed. However, we are finalizing more stringent SFTP standards for PM, 

which focus on the US06 test component, based on newer data and public 

comments. These are also described below.

The Tier 3 SFTP standards are necessary to address emissions during highload conditions, when engines can go into a fuel “enrichment” mode and the 

engine’s controls may temporarily create a rich air/fuel mixture to protect exhaust 

components from thermal damage. Enrichment can increase emissions of 

NMOG+NOX and PM, primarily due to the incomplete combustion that occurs 

under rich conditions and the diminished effectiveness of the catalyst in these 

circumstances. However, enrichment can be minimized or eliminated in current 

and future engines, where components can be thermally protected even under highload conditions by careful electronic management of the air/fuel mixture and the 

combustion process. We are finalizing these SFTP standards, as well as limitations 

on the amount of enrichment that drivers can command (see Section IV.A.4.c 

below) to address this important source of vehicle emission.

We are also finalizing an SFTP composite CO standard of 4.2 g/mi for all 

model years 2017 (or 2018 for LDVs and LDTs over 6000 lbs GVWR and MDPVs) 

and later. This standard represents no effective change from the current Tier 2 

SFTP CO standard, which we believe is already at a level that is sufficiently

stringent. 
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a. SFTP NMOG+NOX Standards

We are finalizing the Tier 3 SFTP NMOG+NOX standards and declining 

fleet-average phase-in schedule as proposed and as presented in Table IV-5 below. 

Most commenters were generally supportive of these standards or silent about them. 

However, several commenters stated that the proposed standards are too lenient, 

based on their evaluation of vehicle emission test data we presented in the NPRM. 

We have considered these comments and have reviewed the data from the NPRM. 

Our conclusion from that data continues to be that the SFTP NMOG+NOx emission 

levels that we are finalizing ensure that manufacturers essentially eliminate fuel 

enrichment events and their emissions consequences, thereby resulting in important 

emissions reductions. See Chapter 1 of the RIA for an analysis of this data. We do 

not believe that significant additional reductions would result from SFTP weighted 

NMOG+NOX standards more stringent than the 50 mg/mi fully phased-in level. In 

addition, we believe that the 50 mg/mi standard will ensure that the SFTP 

performance of future vehicles with future technologies continues to be comparable 

to that of the current fleet. The SFTP emissions value for certification of gaseous 

pollutants will continue to be calculated as a weighted composite value of emissions 

on three cycles (0.35 x FTP + 0.28 x US06 + 0.37 x SC03), as is done for the Tier 2 

SFTP standards. 

To provide flexibility in meeting the fleet-average standards, manufacturers 

will, as proposed, determine the specific SFTP composite standard for each

individual vehicle family and report that self-selected standard and the measured 

emission performance. (These self-selected standards are analogous to “family

emission limits,” or “FELs,” used in other programs (e.g., heavy-duty highway

engine standards).) For each family, a manufacturer will choose any composite 

NMOG+NOX standard, up to 180 mg/mi, in even 10 mg/mi increments. The 

manufacturer will then calculate the sales-weighted average of all the selected 

standards of the families across its fleet and compare that emissions value to the 

applicable fleet-average standards for that model year. Table IV-4 presents the 

declining fleet-average SFTP NMOG+NOX standards.

As discussed in Section IV.A.2.c above, for LDVs and LDTs above 6,000 

lbs GVWR and MDPVs, EPA is providing an alternative phase-in of the 50 mg/mi 

SFTP NMOG+NOX standard. 

b. US06 PM Standards

We are finalizing a single short-term US06 PM standard of 10 mg/mi for 

MYs 2017 and 2018 (or only for MY 2018 for LDVs and LDTs over 6,000 lbs 

GVWR and MDPVs) and a single long-term standard of 6 mg/mi for MY 2019 and 

later. These standards are numerically lower than those we proposed, and less 

complex in their structure. As discussed below and in Chapter 1 of the RIA, a 

substantial body of more recent PM data from a variety of vehicles tested on the 
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US06 cycle has given us greater understanding of the feasible level of control of 

these emissions, both currently and in the timeframe of the Tier 3 standards, 

including what level of control we may reasonably require for the light-duty fleet. 

The standards we are finalizing reflect this review. Much of the more recent data 

was developed late in the development of the NPRM and, although we made it 

available in the rulemaking docket to inform potential commenters, the proposed 

standards did not reflect consideration of the newer data. Since the NPRM, 

additional data from CARB have become available, and we have considered all of 

this information in finalizing the US06 PM standards.

We believe that the fully phased-in US06 PM standard of 6 mg/mi will 

achieve the goal that we presented in the NPRM – to maintain the performance 

being achieved by current well-performing vehicles taking into account reasonable 

compliance margins. Comments from stakeholders representing states, including 

CARB, and several NGOs urged EPA to finalize more stringent standards than 

those proposed, in some cases advocating for standards below 6 mg/mi. 

Conversely, auto industry commenters generally supported the proposed standards. 

We have concluded that the body of recent data clearly shows that the long-term 6 

mg/mi standard, is the appropriate level to prevent any significant “backsliding” in 

US06 PM emissions as new vehicles and technologies enter the fleet. At the same 

time, the 6 mg/mi standard provides a reasonable compliance margin -- about 50% 

above the average levels of current vehicles, which are averaging about 4 mg/mi. A 

long-term standard numerically lower than 6 mg/mi would run counter to our intent 

to bring the emissions performance of all vehicles to that already being 

demonstrated by many vehicles in the current light-duty fleet. We believe the longterm US06 PM standard we are finalizing is appropriate based on all of the 

information available at this time and will not hinder introduction of new 

technologies manufacturers may choose for compliance with the other Tier 3 

standards or other rules. 

The short-term, less-stringent US06 standard of 10 mg/mi (applicable in 

MYs 2017 and 2018) responds to automaker concerns about uncertainties stemming 

from simultaneous regulatory requirements and rapidly evolving exhaust and engine 

technologies in the coming years. We recognize that vehicle control technologies 

for both criteria and GHG emissions are evolving and will continue to do so, 

including an expected expansion of gasoline direct injection (GDI) technologies 

(see IV.A.5.c and the RIA). Also, the transition to lower sulfur in-use gasoline 

required by this rule may create temporary additional challenges in consistently

achieving lower US06 PM emissions (see IV.A.6 and the RIA). We believe that 

most manufacturers will implement similar if not identical emission control 

strategies to comply (or, more often, to continue to comply with) with both the 10 

mg/mi and the 6 mg/mi standards. In so doing, we expect them to use the 

temporary additional compliance margin provided by the 10 mg/mi standard to 

reduce uncertainties about potential variability in performance (in use and, in 
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particular, later in vehicle life) during the early years of developing and 

commercializing their control technologies.256 

The 10 mg/mi standard will expire after MY 2018, and the long-term 

standard of 6 mg/mi will take effect. As the implementation of the program 

continues, we believe a limited degree of relief for testing of in-use vehicles is 

appropriate. Manufacturers commented that because of the industry’s general lack 

of experience with stringent PM standards, especially as the newly-designed 

vehicles age, less stringent standards for in-use testing would reduce near-term 

concerns about performance variability early in the program. We agree, and we 

are finalizing a separate standard of 10 mg/mi for in-use vehicle testing for the 

intermediate years of the program, MYs 2019 through MY 2023. This standard is 

numerically lower than the proposed in-use standards -- again because of the 

availability of improved US06 test data as described above -- but the purpose of 

providing an in-use standard remains the same. The in-use standard, in conjunction 

with the short-term 10 mg/mi standard represents a longer duration for the in-use 

standard than we had proposed, again based on comments from the industry about 

their compliance concerns with new US06 standards. For MY 2024 and later, there 

will be no separate in-use standard and all vehicles will need to meet the long-term 

standard at certification and in use. 

EPA proposed that different US06 PM standards apply to lighter and heavier 

vehicles. The newer US06 PM test data discussed above also make clear that the 

US06 PM performance of current vehicles is not closely related to vehicle weight, 

although the earlier data had indicated that this might be the case. Several 

commenters urged EPA to finalize a single standard for vehicles above and below 

6,000 lbs GVWR based on the newer data. At the same time, auto manufacturers 

generally supported the proposed vehicle weight distinction, asserting a higher 

degree of uncertainty about the emission performance of their larger vehicles, 

especially in the early years of the program and in light of simultaneous technology

challenges. The newer data clearly show that larger vehicles today are generally 

achieving US06 PM levels very similar to smaller vehicles, and well below the 

proposed standards. We are not finalizing separate US06 standards for heavier and 

lighter vehicles because separate standards are unwarranted based on a review of 

the newer data. However, we believe that the short-term 10 mg/mi standard, as well 

as the temporary in-use vehicle testing standard, will significantly reduce 

 

256 We note that the purpose of the percent phase-in schedule for the FTP and US06 PM standards is 

to facilitate the expansion of manufacturers’ PM testing facilities, which have been relatively limited 

in their availability prior to these new emission standards. While effectively providing more time for 

technology development as well as for expansion of facilities, we believe that the PM standards are 

designed to be fully feasible in the early years of the program and do not themselves require the 

phase-in relief, especially given the short-term 10 mg/mi standard and the temporary relaxed in-use 

testing standards.
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manufacturer compliance uncertainties in the early years of the program for all 

vehicles, as discussed above. 

As with the FTP PM standards, manufacturers will comply with the US06 

PM standards with the same increasing minimum percentage of their vehicles, as 

shown in Table IV.5. Also as with the FTP PM phase-in, we are providing the 

option for a manufacturer to choose to certify 10 percent of its total light-duty

vehicle sales in MY 2017 to the new US06 PM standards, including light-duty

vehicles over 6,000 lbs GVWR. 

As discussed in Section IV.A.2.c above, for LDVs and LDTs more than 

6,000 lbs GVWR and MDPVs, EPA is also providing an alternative phase-in of the 

US06 PM standards. 

All of the SFTP/US06 standards are shown in Table IV-4 and Table IV-5. 

Table IV-4 Tier 3 LDV, LDT, and MDPV SFTP Composite Fleet Average 

Standards

Model Year

2017

a

2018 2019 2020 2021 2022 2023 2024 2025 and 

later

NMOG + NOX

(mg/mi)

103 97 90 83 77 70 63 57 50

CO (g/mi) 4.2 a

a

For LDVs and LDTs above 6,000 lbs GVWR and MDPVs, the NMOG+NOX and CO standards 

apply beginning in MY 2018.

Table IV-5 Summary of LDV, LDT, and MDPV Tier 3 SFTP Standards

Program Element Units

Model Year Notes

2017a2018 2019 2020 2021 2022 2023 2024+

NMOG+NOX Standard

(fleet average)

mg/mi Per declining fleet average for cars and trucks (see Table 

IV-4)

b

PM Standards

Phase-in % 20c20 40 70 100 100 100 100
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US06

LDV, LDT, MDPV: 

Certification

mg/mi 10 10

6 6 6 6 6

6 Note d LDV, LDT, MDPV: 

In-Use

10 10 10 10 10

a For LDVs and LDTs above 6,000 lbs GVWR and MDPVs, the standards apply beginning in MY 2018.

b The percent phase-in does not apply to the declining fleet average standards. 

c Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, 

or alternatively with 10 percent of their total LDV, LDT, and MDPV fleet. 

d Manufacturers must test 25 percent of each model year’s durability groups, minimum of 2.

c. Enrichment Limitation for Spark-Ignition Engines

To prevent emissions that result from excessive enrichment from auxiliary

emission control devices (AECD) that are substantially present during the SFTP 

cycles, we are finalizing limitations on the magnitude of enrichment that can be 

commanded, including enrichment episodes encountered during in-use operation. 

During conditions where enrichment is demonstrated to be present on the SFTP, the 

nominal air-to-fuel ratio cannot be richer at any time than the leanest air-to-fuel

ratio required to obtain maximum torque (lean best torque or LBT). An air-to-fuel

ratio of LBT plus a tolerance of 4 percent additional enrichment will be allowed in 

actual vehicle testing to protect for any in-use variance in the air-to-fuel ratio from 

the nominal LBT air-to-fuel determination, for such reasons as air or fuel 

distribution differences from production variances or aging. 

LBT is defined as the leanest air-to-fuel ratio required at a speed and load 

point with a fixed spark advance to make peak torque. Specifically, an increase in 

fuel will not result in an increase in torque while maintaining a fixed spark advance. 

LBT is determined by setting the spark advance to a setting that is less than or equal 

to the spark advance required for best torque (MBT) and maintaining that spark 

advance when sweeping the air-to-fuel ratio. This fixed spark advance requirement 

is intended to prevent torque changes related to spark changes masking true LBT. 

One manufacturer commented that there is no universally accepted definition or 

procedure to determine LBT so we should retain the Tier 2 LBT requirements. We 

believe that the proposed definition provides sufficient clarity and will generally 

agree with most manufacturers’ internal definition of LBT. Additionally, we are 

finalizing the flexibility that manufacturers may request approval of an alternative 

LBT definition for a unique technology or control strategy. The Agency may

determine that an enrichment amount is excessive or not necessary and therefore 

deem that the approach does not meet the air-to-fuel ratio requirements. 

Enrichment required for thermal protection will continue to be allowed 

upon demonstration of necessity to the Agency, based upon temperature limitations 

of the engine or exhaust components. Manufacturers will be required to provide 

descriptions of all components requiring thermal protection, temperature limitations 
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of the components, how the enrichment strategy will detect over-temperature 

conditions and correct them, and a justification regarding why the enrichment is the 

minimum necessary to protect the specific components. The Agency may

determine that the enrichment is not justified or is not the minimum necessary based 

on the use of engineering judgment using industry-reported thermal protection 

requirements.

A manufacturer commented that this requirement to report enrichment 

requirements for component protection for every application is burdensome and 

unnecessary. EPA believes that closer review of off-cycle enrichment by the 

agency, including enrichment for component protection, is necessary to ensure 

emissions are well controlled under all operating conditions. While this 

requirement may in some cases require additional resources at certification, this 

information has generally been required to be maintained by manufactures to 

support use of enrichment as an auxiliary emission control device (AECD) and 

therefore should be an exercise of reporting existing records for most 

manufacturers. 

The requirements described in this section apply for vehicles certified to any

of the Tier 3 standards.

5. Feasibility of the NMOG+NOX and PM Standards

In the proposal, we concluded that all of the Tier 3 emissions standards are 

technologically feasible in the time frame of the program. The technical 

conclusions we reached at that time have been further reinforced by information we 

received in the public comments or has otherwise become available and placed in 

the docket for this rulemaking. After considering the comments received and with 

additional supporting information in Chapter 1 of the RIA, we conclude that the 

Tier 3 standards are feasible and reasonable, considering lead-time provided and 

expected compliance costs. 

For each of the emission standards, the lead time provided by the program is 

more than sufficient for all manufacturers to comply. First, manufacturers in many

cases are already adopting complying technologies for reasons other than this 

rulemaking. For example, many of the technologies that manufacturers have begun

to develop for model years as early as MY 2014 in response to the CARB LEV III 

FTP and SFTP NMOG+NOX standards for the California market will likely 

represent steps toward compliance with this national program. Similarly, 

manufacturers have been producing some limited vehicle offerings since as early as 

MY 2000 that comply with our final MY 2025 standards in response to the CARB 

PZEV requirements. In addition, as described above, our program incorporates a 

number of phase-in provisions that will ease the transition to compliance, including 

time some manufacturers may need to install PM testing capability and to ramp up 

production on a national scale. This feasibility assessment is based on a variety of 
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complementary technical data, studies, and analyses. As described below, these 

include our analysis of the stringency of the standards as compared to current Tier 2 

emission levels. We also discuss below our observation that manufacturers are 

currently certifying several vehicle models under the California LEV II program 

that could likely achieve the Tier 3 NMOG+NOX and PM standards or similar 

levels. EPA has assessed the emissions control challenges manufacturers will

generally face (e.g., cold start NMOG reductions and running (warmed-up) NOX

emissions under typical and more aggressive driving conditions) and the 

corresponding technologies that we expect to be available to manufacturers to meet 

these challenges. Our feasibility assessment accounts for the fact that the Tier 3 

program will apply to all types of new vehicles, ranging from small cars to large 

pick-up trucks and MDPVs and representing a wide diversity in applications and in 

specific engine designs. 

It is important to note that our primary assessment of the feasibility of 

engine and emission control technologies is based on the assumption that vehicles 

will be certified on gasoline with a fuel sulfur content of 10 ppm and operated on 

in-use gasoline with an average of 10 ppm sulfur.257 Therefore, our primary

assessment does not incorporate the degradation of emission control system caused 

by higher levels of sulfur content, as is discussed in Section IV.A.6 below and 

further discussed in the RIA. This assessment reinforces the critical role of gasoline 

sulfur control in making it possible for EPA to establish emission standards at these 

very stringent levels. See Section IV.6 below for a full discussion of our current 

knowledge of the effects of gasoline sulfur on current Tier 2 vehicle emissions as 

well as our projections of how we expect that sulfur will affect compliance on 

vehicles with standards in the range of the Tier 3 standards. The projections are 

based on extensive EPA testing of Tier 2 vehicles as well as targeted evaluation of 

passenger cars and heavier trucks performing at or near the Tier 3 Bin 30 (30 mg/mi 

NMOG+NOX) including manufacturer supplied data of a prototype Tier 3 lightduty truck as discussed in Section IV.6. 

Since there are multiple aspects to the Tier 3 program, it is necessary to 

consider technical feasibility in light of the different program requirements and their 

interactions with each other. In many cases, manufacturers will be able to address 

more than one requirement with the same general technological approach (e.g., 

faster catalyst light-off can improve both FTP NMOG+NOX and PM emissions). 

At the same time, the feasibility assessment must consider that different 

technologies may be needed on different types of vehicle applications (e.g., cars 

versus trucks) and must consider the relative effectiveness of these technologies in 

 

257 Our technology, feasibility, and cost assessments are also consistent with an assumption that 

certification fuel will contain 10 percent ethanol and will have other properties as specified in 

Section IV.F below.
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reducing emissions for the full useful life of the vehicle while operating on expected 

in-use fuel. For example, certain smaller vehicles with correspondingly small 

engines may be less challenged to meet FTP standards than larger vehicles with 

larger engines. Conversely, these smaller vehicles may have more difficulty

meeting the more aggressive SFTP requirements than vehicles with larger and more 

powerful engines. Additionally, the ability to meet the SFTP emission requirements 

can also be impacted by the path taken to meet the FTP requirements (e.g., larger 

volume catalysts for US06 emissions control vs. smaller catalysts for improved FTP 

cold-start emissions control). Throughout the following discussion, we address 

how these factors, individually and in interaction with each other, affect the 

feasibility of the final program. 

a. FTP NMOG+NOX Standards

The Tier 3 emission requirements include stringent NMOG+NOX standards 

on the FTP that will require new vehicle hardware in order to achieve the 30 mg/mi 

fleet average level in MY 2025. The type of new hardware that will be required will

vary depending on the specific application and emission challenges. Smaller 

vehicles with corresponding smaller engines will generally need less new hardware 

while larger vehicles may need additional hardware and improvements beyond what 

will be needed for the smaller vehicles. While some vehicles, especially larger light 

trucks, may face higher costs in meeting the standards, it is important to remember 

that not every vehicle needs to meet the standard. The program has been structured 

to provide higher emission standard “bins” (see Table IV-1 above) to which 

manufacturers may certify more challenged vehicles, so long as these vehicles are 

offset with vehicles certified in lower emission bins such that the fleet-wide average 

meets the standards. We believe that the availability of the less-stringent bins will

allow for the balancing of feasibility and cost considerations of compliance 

strategies for all vehicles. In the Tier 2 program, manufacturers took advantage of 

this flexibility, especially in the early years of the program. Then, as technologies 

improved and/or became less expensive and the need for averaging diminished, 

manufacturers began certifying all or most of their fleets to the average bin (Tier 2 

Bin 5). We anticipate that manufacturers will follow a similar trend with the Tier 3 

standards, relying on fleet averaging more significantly in the transitional years but 

certifying increasing numbers of their vehicles to the final fleet average standard of 

30 mg/mi in the later years of the program. 

In order to assess the technical feasibility of a 30 mg/mi NMOG+NOX

national fleet average FTP standard, EPA conducted two supporting analyses. The 

initial analyses performed were of the current Tier 2 and LEV II fleets. This 

provided a baseline for the current federal fleet emissions performance, as well as 

the emissions performance of the California LEV II fleet. The second consideration 

was a modal analysis of typical vehicle emissions under certain operating 

conditions. In this way EPA determined the specific emissions performance 

challenges that vehicle manufacturers will face in meeting the lower fleet average 
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emission standards. Each of these considerations is described in greater detail 

below.

The current Tier 2 federal fleet is certified to an average of Tier 2 Bin 5, 

equivalent to 160 mg/mi NMOG+NOX.

258

 As an example, for MY 2009 when the 

Tier 2 program was fully implemented across all vehicle types, 92 percent of LDVs 

and LDT1s were certified to Tier 2 Bin 5 and 91 percent of LDT2s through LDT4s 

were certified to Tier 2 Bin 5. This trend has generally continued through MY 2013 

as the most recent certification results indicate that manufacturers are continuing to 

certify primarily to Tier 2 Bin 5 standards for the federal fleet however there has 

been a shift to more certifications using the cleaner bins as discussed in the RIA.

This is not an unexpected result as there is no motivation prior to implementation of 

the Tier 3 rulemaking for vehicle manufacturers to produce a federal fleet that overcomplies with respect to the existing Tier 2 standards. By comparison, in the 

California fleet where compliance with the declining fleet average NMOG 

requirement and the “PZEV” program requires manufacturers to certify vehicles to 

cleaner levels, only 30 percent of the LDVs and LDT1s are certified to Tier 2 Bin 5 

and 60 percent are certified to cleaner bins such as Tier 2 Bin 3 and 4. The situation 

regarding the truck fleet in California is similarly stratified, with 37 percent of the 

LDT2s through LDT4s being certified to Tier 2 Bin 5 and 55 percent being certified 

to the cleaner Tier 2 Bin 3 and 4. In many cases identical vehicles are being 

certified to a lower standard in California and a higher standard federally simply

because there is no incentive to over perform to the federal standards. We note that 

vehicles certified to a lower standard in California are operated on gasoline with an 

average sulfur content of 10 ppm and thereby are able to maintain their emissions 

performance in-use. Based on these patterns of federal and California certification, 

EPA believes that much of the existing Tier 2 fleet could currently be certified to a 

lower federal fleet average immediately, with no significant feasibility concerns, if 

lower sulfur gasoline were made available nationwide.

Regardless of the Tier 2 bin standards at which manufacturers choose to 

certify their vehicles, actual measured emissions performance of these vehicles is 

typically well below the numerical standards. This difference is referred to as 

“compliance margin” and is a result of manufacturers’ efforts to address all the 

sources of variability, including: 

 Test-to-test variability (within one test site and lab-to-lab)

 Build variation expectations

 

258 The Tier 2 program does not combine NMOG and NOX emissions into one fleet-average 

standard. The fleet-average standard in that program is for NOX emissions alone. The NOX fleetaverage requirement of .07 gm/mi is the same level as the Bin 5 NOX standard.
Page 116 of 529

 Manufacturing tolerances and stack-up

 Vehicle operation (for example: driving habits, ambient temperature, 

etc.)

 Fuel composition

 The effects of fuel sulfur on exhaust catalysts and oxygen sensors 

 The effects of other fuel components, including ethanol and gasoline 

additives

 Oil consumption

 The impact of oil additives and oil ash on exhaust catalysts and oxygen 

sensors

For MY 2009 thru MY 2013, the compliance margin for a Tier 2 Bin 5 

vehicle averaged approximately 60 percent. In other words, actual vehicle 

emissions performance was on average about 40 percent of a 160 mg/mi 

NMOG+NOX standard, or about 64 mg/mi. By comparison, for California-certified 

vehicles, the average Super Ultra Low Emission Vehicle (SULEV) compliance 

margin was somewhat less for the more stringent standards, approximately 50 

percent. We believe that the recent California experience is a likely indicator of 

compliance margins that manufacturers will design for in order to comply with the 

Tier 3 FTP standards. Thus, a typical Tier 2 Bin 5 vehicle, performing at 40 percent 

of the current standard (i.e., at about 64 mg/mi) will need improvements sufficient 

to reach about 15 mg/mi (50 percent of a 30 mg/mi standard). 

To understand how the several currently-used technologies described below 

could be used by manufacturers to reach the stringent Tier 3-NMOG+NOX

standards, it is helpful to consider emissions formation in common modes of 

operation for gasoline engines, or modal analysis.259 The primary challenge faced 

by manufacturers for producing Tier 3 compliant light-duty gasoline vehicle 

powertrains will be keeping warmed-up running emissions at effectively zero 

emissions levels while reducing the emissions during cold-start operation which, 

based on modal analysis of a gasoline-powered vehicle being operated on the FTP 

cycle, occurs during about the first 50 seconds after engine start. Thus, we believe 

that to comply with the Tier 3 FTP standards, manufacturers will focus on effective 

control of these cold-start emissions while maintaining zero running emissions; this 

is only possible when sulfur levels in the fuel do not degrade catalyst performance. 

 

259 A modal analysis provides a second-by-second view of the total amount of emissions over the 

entire cycle being considered.
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As discussed below, light-duty manufacturers are already applying several 

technologies capable of significant reductions in these cold start emissions to 

vehicles currently on the road. 

During the analysis of current vehicles certified to the cleanest emission 

levels (Tier 2 Bin 2 and LEV II SULEV) it was noted that no large pick-ups 

equipped with their application specific engines were performing at the 30 mg/mi 

NMOG+NOX level. We believe that these applications may be the most 

challenging due to the fact that the design criteria required to provide the utility

aspect may have direct impact on their ability to implement some of the 

technologies described in section IV.A.5.d below. Since these vehicles represent a 

substantial and important part of the light- duty fleet, EPA performed a technical 

feasibility study directly targeting this class of vehicles. 

In order to assess the technical feasibility of a 30 mg/mi FTP NMOG+NOX

standard, EPA purchased a 2011 Chevrolet Silverado heavy-light-duty (LDT4) 

pickup truck with a developmental goal of modifying the truck to achieve exhaust 

emission levels in compliance with the Tier 3 Bin 30 emissions standards including 

a reasonable compliance margin. The truck was equipped with a 5.3L V8 with 

General Motors’ “Active Fuel Management” cylinder deactivation system. This 

particular truck was chosen as an example of a Tier 3 prototype in part because 

cylinder deactivation is a key technology for light-truck compliance with future 

GHG standards and in part because it achieved very low emissions in the OEM, 

Tier 2-compliant configuration (certified to Tier 2 Bin 4). A prototype exhaust 

system was obtained from MECA consisting of high-cell-density (900 cpsi) thinwall (2.5 mil), high-PGM, close-coupled Pd-Rh catalysts with an additional underbody Pd-Rh catalyst. The total catalyst volume was approximately 116 in3 with a 

specific PGM loading of 125 g/ft3and approximate loading ratio of 0:80:5 

(Pt:Pd:Rh). Third-party (non-OEM) EMS calibration tools were used to modify the 

powertrain calibration in an effort to improve catalyst light-off performance. The 

final test configuration used approximately 4 degrees of timing retard and 

approximately 200 rpm higher idle speed relative to the OEM configuration during 

and immediately following cold-start. The exhaust catalyst system and HEGO 

sensors were bench aged to an equivalent 150,000 miles using standard EPA 

accelerated catalyst bench-aging procedures. The truck was tested on California 

LEV III E10 certification fuel at 9 ppm gasoline sulfur levels.

The EPA Tier 3 prototype Silverado achieved NMOG+NOx emissions of 18 mg/mi 

on the 9 ppm S fuel. The NMOG+NOx emissions were approximately 60% of the 

Bin 30 standard and thus are consistent with meeting the Tier 3 Bin 30 exhaust 

emissions standard with a moderate compliance margin. The technologies used on 

the prototype Silverado to achieve these emission levels are common approaches 

used today on smaller vehicles. They do not compromise any of the design utility

of this vehicle class and are some of the same approaches we expect manufacturers 

to use to meet the Tier 3 Bin 30 exhaust emissions standards.
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b. SFTP NMOG+NOX Standards

The increase in the stringency of the SFTP NMOG+NOX standards, 

specifically across the US06 cycle, will generally only require additional focus on 

fuel control of the engines and diligent implementation of new technologies that 

manufacturers are already introducing or are likely to introduce in response to the 

current and 2017 LD GHG emission standards. These include downsized gasoline 

direct injection (GDI) and turbocharged engines, which may also include 

improvements to the engine and emission control hardware to tolerate higher 

combustion and exhaust temperatures expected in these future GHG-oriented 

engine designs when under higher loads. The upgraded materials or components 

will enable manufacturers to rely less on fuel enrichment during high-speed/highload operation to protect components from overheating. This fuel enrichment is 

currently the source of elevated VOC, NOX, and PM emissions seen in a subset of 

the current Tier 2 fleet.

With respect to enrichment, the primary method available to manufacturers 

to protect the catalyst and other exhaust components from over-temperature 

conditions has been changes to the fuel/air mixture by increasing the fuel fraction, 

but this is no longer the only tool available to manufacturers for this purpose. With 

the application of electronic throttle controls, variable valve timing, exhaust gas 

recirculation and other exhaust temperature influencing technologies on nearly

every light-duty vehicle, the manufacturer has the ability to systematically control 

the operation and combustion processes of the engine to minimize or altogether 

avoid areas and modes of operation where thermal issues can occur. While some of 

these solutions could in some cases result in a small and temporary reduction in 

vehicle performance (absolute power levels), we believe that it could be an effective 

way to reduce NMOG+NOX emissions over the SFTP test. 

Additionally, some components, especially catalysts, can experience 

accelerated thermal deterioration that occurs when operating at higher temperatures 

for more time than expected under normal operation (e.g., trailer towing, mountain 

grades). Some upgrades of existing vehicle emission control technology, like 

catalyst substrates and washcoats may be required to limit thermal deterioration and 

ensure vehicle emissions compliance throughout the useful life of the vehicle. 

In order to assess the technical feasibility of a 50 mg/mi NMOG+NOX

national fleet average SFTP standard, EPA conducted an analysis of SFTP levels of 

Tier 2 and LEV II vehicles. The analysis was performed on the US06 results from 

current Tier 2 and LEV II vehicles tested in the in-use verification program (IUVP) 

by manufacturers and submitted to EPA. This analysis provided a baseline for the 

current Tier 2 and LEV II fleet emissions performance, as well as the SFTP 

emissions performance capability of the cleanest vehicles meeting the Tier 3 FTP 

standards. The analysis concluded that most vehicles in the IUVP testing program 

are already capable of meeting the composite SFTP standard of 50 mg/mi when the 
Page 119 of 529

Tier 3 FTP standard levels are factored into the composite calculation. With the 

technological improvements already underway as discussed above, we believe all 

MY 2017 and later vehicles will be able to comply with the SFTP standards, either 

directly or through the flexibility of the averaging, banking and trading program. 

For further information on the analysis see Chapter 1 of the RIA.

c. FTP and SFTP PM Standards

As described above for NMOG+NOX over the SFTP, the increase in the 

stringency of the FTP and SFTP PM standards will generally also only require 

additional focus on fuel control of the engines and attention to PM emissions during 

the implementation of new technologies like gasoline direct injection (GDI) and 

turbocharged engines. Some upgrades of existing vehicle emission control 

technology may be required to ensure vehicle emissions performance is maintained 

throughout the useful life of the vehicle. These upgrades may include 

improvements to the engine to control wear that could result in increased PM from 

oil consumption and selection of GDI systems that will be capable of continuing to 

perform optimally even as the systems age. 

We based our conclusions about the ability of manufacturers to meet the PM 

standards largely on the PM performance of the existing fleet, both on the FTP and 

SFTP. In the case of FTP testing of current vehicles, data on both low and high 

mileage light-duty vehicles demonstrate that the majority of vehicles are currently

achieving levels at or below the Tier 3 FTP PM standards. 

The testing results can be found in Chapter 1 of the RIA. A small number of 

vehicles are at or just over the Tier 3 FTP PM standard at low mileage and could 

require calibration changes and/or catalyst changes to meet the new standards. It is 

our expectation that the same calibration and catalyst changes required to address 

NMOG will also provide the necessary PM control. Vehicles that currently have 

higher PM emissions over the FTP or SFTP at higher mileages will likely be 

required to control oil consumption and combustion chamber deposits. 

We also analyzed PM test data results on the US06 test cycle from Tier 2 

vehicles. The data show that many vehicles are already at or below the Tier 3 

standards on the US06 test cycle. Vehicles that have high PM emission rates on the 

US06 will likely need to control enrichment and oil consumption, particularly later 

in life. As described above for SFTP NMOG+NOX control, enrichment can be 

more accurately managed through available electronic engine controls. The 

strategies for reducing oil consumption are similar to those described above for 

controlling oil consumption on the FTP. However, given the higher engine speeds 

experienced on the US06 and the increase in oil consumption that can accompany

this kind of operation, manufacturers will most likely focus on oil sources stemming 

from the piston to cylinder interface and positive crankcase ventilation (PCV). 
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Manufacturers have informed us that they have already reduced or are 

planning to reduce the oil consumption of their engines by improved sealing of the 

paths of oil into the combustion chamber and improved piston-to-cylinder 

interfaces. Auto manufacturers have stated that they are already taking or 

considering these actions to address issues of customer satisfaction and cost of 

ownership. In addition, many vehicle manufacturers acknowledge the relationship 

between combustion chamber deposits and PM formation and are actively pursuing 

design changes to mitigate fuel impingement within the combustion chamber and its 

commensurate PM effects. Both types of controls are being widely applied by

manufacturers today.

d. Technologies Manufacturers are Likely to Apply

Most of the technologies expected to be applied to light-duty vehicles to 

meet the stringent Tier 3 standards will address the emissions control system’s 

ability to reduce emission during cold start while maintaining zero or near zero 

running emissions. The effectiveness of current vehicle emissions control systems 

at reducing cold start emissions depends in large part on the time it takes for the 

catalyst to light off, which is typically defined as the catalyst reaching a temperature 

of 250 °C. In order to improve catalyst light-off, we expect that manufacturers will

add technologies that provide heat from combustion more readily to the catalyst or 

improve the catalyst efficiency at lower temperatures. These technologies include 

calibration changes, catalyst platinum group metals (PGM) loading and strategy,

thermal management, close-coupled catalysts, and secondary air injection, all which 

generally improve emission performance of all pollutants. In some cases where the 

catalyst light-off and efficiency are not enough to address the cold start NMOG 

emissions, hydrocarbon adsorbers may be applied to trap hydrocarbons until such 

time that the catalyst is lit off. Note that with the exception of hydrocarbon 

adsorbers each of these technologies addresses NMOG, NOX, and PM performance. 

The technologies are described in greater detail below. Additional information on 

these technologies can also be found in Chapter 1 of the RIA.

 Engine Control Calibration Changes – These include changes to retard 

spark and/or adjust air/fuel mixtures such that more combustion heat is 

created during the cold start. Control changes may include injection 

strategies in GDI applications, unique cold-start variable valve timing 

and lift, and other available engine parameters. Engine calibration 

changes can affect NMOG, NOX and PM emissions.

 Catalyst PGM Loading – Additional PGM loading, increased loading of 

other active materials, and improved dispersion of PGM and other active 

materials in the catalyst provide a greater number of sites available to 

catalyze emissions and addresses NMOG, NOX and PM emissions. 

Catalyst PGM loading, when implemented in conjunction with low 
Page 121 of 529

sulfur gasoline, will effectively eliminate NOX emissions under warmedup conditions.

 Thermal Management – This category of technologies includes all 

design attributes meant to conduct the combustion heat into the catalyst 

with minimal cooling. This includes insulating the exhaust piping 

between the engine and the catalyst, reducing the wetted area of the 

exhaust path, reducing the thermal mass of the exhaust system, and/or 

using close-coupled catalysts (i.e., the catalysts are packaged as close as 

possible to the engine’s cylinder head to mitigate the cooling effects of 

longer exhaust piping). Thermal management technologies primarily 

address NMOG emissions, but also affect NOX and PM emissions.

 Secondary Air Injection – By injecting air directly into the exhaust 

stream, close to the exhaust valve, combustion can be maintained within 

the exhaust, creating additional heat by which to increase the catalyst 

temperature. The air/fuel mixture must be adjusted to provide a richer 

exhaust gas for the secondary air to be effective. There can be a NOx 

emissions disbenefit to use of secondary air injection since it can impact 

the ability of oxygen storage components (OSC) within the catalyst to 

take up excess oxygen as necessary to promote NOx reduction reactions 

immediately following cold start conditions.

 Hydrocarbon Adsorber – Traps hydrocarbons during a cold start until 

the catalyst lights off, and then releases the hydrocarbons to be 

converted by the catalyst.

 Gasoline Sulfur – The relative effectiveness for NMOG and NOX

control of the exhaust-catalyst related technologies is constrained by 

gasoline fuel sulfur levels. Thus, reduced sulfur in gasoline is an 

enabling technology to achieve the standards and maintain this 

performance during in-use operation. We discuss the relationship 

between gasoline sulfur and emissions in greater detail in Section IV.6 

below and in the RIA. 

Several commenters indicated that large light-duty trucks (e.g., pickups and 

full-size sport utility vehicles (SUVs) in the LDT3 and LDT4 categories) will be the 

most challenging light-duty vehicles to bring into compliance with the Tier 3 

NMOG+NOX standards at the 30 mg/mi corporate average emissions level. A 

similar challenge was addressed when large light-duty trucks were brought into 

compliance with the Tier 2 standards over the past decade. Figure IV-1 provides a 

graphical representation of the effectiveness of Tier 3 technologies for large lightduty truck applications. A compliance margin is shown in both cases. Note that the 

graphical representation of the effectiveness of catalyst technologies on NOX and 
Page 122 of 529

NMOG when going from Tier 2 to Tier 3 levels also includes a reduction in 

gasoline sulfur levels from 30 ppm to 10 ppm.
Page 123 of 529

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

Tier 2 Bin 5 LDT3/4

w/30 ppm S Gasoline

Tier 3 LDT3/4

w/10 ppm S Gasoline

N

M

O

G+N

Ox Emissoins (mg/mi)@ 120,000 miles

NMOG+NOx Emissons of Tier 3 LD3/T4

NMOG+NOx Emissions of Tier 2 Bin 5 LDT3/4 

60% 

Compliance

Margin

20-40% Compliance Margin

Tier 2 Bin 5 NMOG+NOx Standard

Tier 3 NMOG+NOx Standard

Passive HC Adsorber

Thermal Management

Secondary 

Air Injection

67% Emissions 

Reduction

Catalyst 

PGM Loading

Figure IV-1: Contribution of Tier 3 Technologies to Large Light-Duty Truck 

Compliance260

 

260 The technologies and levels of control in this figure are based on a combination of confidential 

business information submitted by auto manufacturers and suppliers, public data, and EPA staff 

engineering judgment.
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6. Impact of Gasoline Sulfur Control on the Effectiveness of the Vehicle 

Emission Standards

In this section, we discuss the impact of gasoline sulfur control on the 

feasibility of the Tier 3 vehicle emissions standards and on the exhaust emissions of 

the existing in-use vehicle fleet. Section IV.A.6.a describes the chemistry and 

physics of the impacts of gasoline sulfur compounds on exhaust catalysts. Sections 

IV.A.6.b, c and d summarize research on the impacts of gasoline sulfur on vehicles 

utilizing various degrees of emission control technology, with Section IV.A.6.b 

summarizing historical studies on the impact of gasoline sulfur on vehicle 

emissions, Section IV.A.6.c describing impacts on Tier 2 vehicles and the existing 

light-duty vehicle fleet, and Section IV.A.6.d describing impacts on vehicles using 

technology consistent with what we expect to see in the future Tier 3 vehicle fleet. 

Section IV.A.6.e provides EPA’s assessment of the level of gasoline sulfur control 

necessary for light-duty vehicles to comply with Tier 3 exhaust emission standards. 

EPA’s primary findings are:

• Reducing gasoline sulfur content to a 10 ppm average will provide 

immediate and significant exhaust emissions reductions to the current, 

in-use fleet of light-duty vehicles.

• Reducing gasoline sulfur content to an average of 10 ppm will enable 

vehicle manufacturers to certify their entire product lines of new lightduty vehicles to the final Tier 3 Bin 30 fleet average standards. Without 

such sulfur control it would not be possible for vehicle manufacturers to 

reduce emissions sufficiently below Tier 2 levels to meet the new Tier 3 

standards because it would require offsetting significantly higher 

exhaust emissions resulting from the higher sulfur levels. EPA has not 

identified any existing or developing technologies that would

compensate for or offset the higher exhaust emissions resulting from 

higher fuel sulfur levels. 

a. Gasoline Sulfur Impacts on Exhaust Catalysts 

Modern three-way catalytic exhaust systems utilize platinum group metals 

(PGM), metal oxides and other active materials to selectively oxidize organic 

compounds and carbon monoxide in the exhaust gases. These systems 

simultaneously reduce NOx when air-to-fuel ratio control operates in a condition of 

relatively low amplitude/high frequency oscillation about the stoichiometric point. 

Sulfur is a well-known catalyst poison. There is a large body of work demonstrating 

sulfur inhibition of the emissions control performance of PGM three-way exhaust 
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catalyst systems.261,262,263,264,265,266,267,268,269,270 The nature of sulfur interactions with 

washcoat materials, active catalytic materials and catalyst substrates is complex and 

varies with catalyst composition, exhaust gas composition and exhaust temperature. 

The variation of these interactions with exhaust gas composition and temperature 

means that the operational history of a vehicle is an important factor; continuous 

light-load operation, throttle tip-in events and enrichment under high-load 

conditions can all impact sulfur interactions with the catalyst. 

Sulfur from gasoline is oxidized during spark-ignition engine combustion 

primarily to SO2 and, to a much lesser extent, SO3

-2

. Sulfur oxides selectively 

chemically bind (chemisorb) with, and in some cases react with, active sites and 

coating materials within the catalyst, thus inhibiting the intended catalytic reactions. 

Sulfur oxides inhibit pollutant catalysis chiefly by selective poisoning of active 

PGM, ceria sites, and the alumina washcoating material (see Figure IV-2).271 The 

amount of sulfur retained by an exhaust catalyst system is primarily a function of 

the concentration of sulfur oxides in the incoming exhaust gases, air-to-fuel ratio 

feedback and control by the engine management system, the operating temperature 

of the catalyst and the active materials and coatings used within the catalyst. 

In their supplemental comments to the Tier 3 proposal, API criticized the 

use of emissions data generated using gasoline with sulfur content outside of the 

range of 10 ppm to 30 ppm within EPA and other analyses of the impacts of 

 

261 Beck, D.D., Sommers, J.W., DiMaggio, C.L. (1994). Impact of sulfur on model palladium-only 

catalysts under simulated three-way operation. Applied Catalysis B: Environmental 3, 205-227.

262 Beck, D.D., Sommers, J.W. (1995). Impact of sulfur on the performance of vehicle aged 

palladium monoliths.” Applied Catalysis B: Environmental 6, 185-200.

263 Beck, D.D., Sommers, J.W., DiMaggio, C.I. (1997). Axial characterization of oxygen storage 

capacity in close coupled lightoff and underfloor catalytic converters and impact of sulfur. Applied 

Catalysis B: Environmental 11, 273-290.

264 Waqif, M., Bazin, P., Saur, O. Lavalley, J.C., Blanchard, G., Touret, O. (1997), Study of ceria 

sulfation. Applied Catalysis B: Environmental 11, 193-205.

265 Bazin, P., Saur, O. Lavalley, J.C., Blanchard, G., Visciglio, V., Touret, O. (1997). “Influence of 

platinum on ceria sulfation.” Applied Catalysis B: Environmental 13, 265-274.

266 Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. (2000). Fuel Property Requirement 

for Advanced Technology Engines. SAE Technical Paper 2000-01-2019.

267 Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. (2001). “Fuel properties for 

advanced engines.” Automotive Engineering International 109 12, 117-120.

268 Kubsh, J.E., Anthony, J.W. (2007). The Potential for Achieving Low Hydrocarbon and NOX

Exhaust Emissions from Large Light-Duty Gasoline Vehicles. SAE Technical Paper 2007-01-1261.

269 Shen, Y., Shuai, S., Wang, J. Xiao, J. (2008). Effects of Gasoline Fuel Properties on Engine 

Performance. SAE Technical Paper 2008-01-0628.

270 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300.

271 Heck, R.M., Farrauto, R.J. (2002). Chapter 5: Catalyst Deactivation in Catalytic Air Pollution 

Control, 2nd Edition. John Wiley and Sons, Inc.
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gasoline sulfur on exhaust emissions from current in-use (Tier 2) and future (Tier 3) 

light-duty vehicles. Specific examples include: 

 Comparisons of exhaust emissions at 5 ppm and 28 ppm gasoline 

sulfur levels within the recent EPA study of emissions from Tier 2 

vehicles272

 Comparison of exhaust emissions of a SULEV vehicle at 8 ppm and 

33 ppm gasoline sulfur levels within the Takei et al. study273

 Comparison of exhaust emissions of a PZEV vehicle at 3 ppm and 

33 ppm gasoline sulfur levels within the Ball et al. study.

274

The relationship between changes in gasoline sulfur content and NOx, HC, 

NMHC and NMOG emissions is typically linear. The linearity of sulfur impacts on 

NOx, NMHC and NMOG emissions is supported by past studies with multiple fuel 

sulfur levels all of which compare gasoline with differing sulfur levels that are 

below approximately 100 ppm (e.g., CRC E-60 and 2001 AAM/AIAM programs as 

well as comments on this rulemaking submitted by MECA).

275,276,277 An assumption 

of linearity of the effect of gasoline sulfur level on catalyst efficiency between any 

two test fuels with differing sulfur levels is reasonable given that the mass flow rate 

of sulfur in exhaust gas changes in proportion to its concentration in the fuel, and 

that the chemistry of adsorption of sulfur on the active catalyst sites is an 

approximately-first-order chemisorption until all active sites within a catalyst reach 

an equilibrium state relative to further input of sulfur compounds. The relative 

linearity of the effect of gasoline sulfur level on NMOG and NOx emissions allows 

exhaust emissions results generated within EPA and other studies of gasoline sulfur 

at levels immediately above or below either 10 ppm or 30 ppm to be normalized to 

either 10 ppm sulfur (Tier 3 gasoline) or to 30 ppm sulfur (Tier 2 gasoline, which 

 

272

 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

273 Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. (2000). Fuel Property Requirement 

for Advanced Technology Engines. SAE Technical Paper 2000-01-2019. 

274 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300. 

275 Coordinating Research Council. 2003. “The Effect of Fuel Sulfur on NH3 and Other Emissions 

from 2000-2001 Model Year Vehicles.” CRC Project No. E-60 Final Report. Accessed on the 

Internet on 12/4/2013 at the following URL: http://www.crcao.com/reports/recentstudies2003/E60%20Final%20Report.pdf. 

276 Alliance of Automobile Manufacturers. 2001. “AAM-AIAM Industry Low Sulfur Test 

Program.”

277 Manufacturers of Emission Controls Association. 2013. “The Impact of Gasoline Fuel Sulfur on 

Catalytic Emission Control Systems.”
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are used in the analysis of the impacts of the Tier 3 gasoline standards on existing 

in-use vehicles and future Tier 3 vehicles.

In their supplemental comments to the Tier 3 proposal, API also commented 

that EPA did not show the sulfur impact on exhaust emissions at intermediate sulfur 

levels between 10 ppm and 30 ppm. In response, based on the relative linearity of 

the effect of gasoline sulfur level on NMOG and NOx emissions allowing exhaust 

emissions to be estimated for gasoline sulfur levels between 10 and 30 ppm, data in 

EPA’s analysis shows increases NMOG+NOx emissions (as fuel sulfur increases) 

that become more severe (i.e., higher percentage increase in NMOG+NOx 

emissions) for vehicles with extremely low278 exhaust emission (SULEV, PZEV, 

LEV III, Tier 3) as described in further detail in Sections IV.A.6.d and e.

100 Å

Catalytic Site Deactivated by Sulfur Poisoning

Active Catalytic Site

Alumina Washcoat

Monolith Substrate

Figure IV-2 Functional schematic showing selective poisoning of active 

catalytic sites by sulfur compounds. Adapted from Heck and Farrauto 2002.

279

 

278 Vehicles that meet the cleanest emission standards by demonstrate very low cold start NMOG 

and NOx emissions and zero or near-zero running NMOG and NOx emissions.

279 Heck, R.M., Farrauto, R.J. (2002). Chapter 5: Catalyst Deactivation in Catalytic Air Pollution 

Control, 2nd Edition. John Wiley and Sons, Inc.
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Selective sulfur poisoning of platinum (Pt) and rhodium (Rh) is primarily

from surface-layer chemisorption. Sulfur poisoning of palladium (Pd) and ceria 

appears to be via chemisorption combined with formation of more stable metallic 

sulfur compounds, e.g. PdS and Ce2O2S, present in both surface and bulk form (i.e., 

below the surface layer).

280,281,282,283

 Ceria, zirconia and other oxygen storage 

components (OSC) play an important role that is crucial to NOX reduction over Rh 

as the engine air-to-fuel ratio oscillates about the stoichiometric closed-loop control 

point. 284 Ceria sulfation interferes with OSC functionality within the catalyst and 

thus can have a detrimental impact on the catalyst’s ability to effectively reduce 

NOx emissions. Water-gas-shift reactions are important for NOX reduction over 

catalysts combining Pd and ceria. This reaction can be blocked by sulfur poisoning 

and may be responsible for observations of reduced NOX activity over Pd/ceria 

catalysts even with exposure to fairly low levels of sulfur (equivalent to 15 ppm in 

gasoline).285, 286 Pd is also of increased importance for meeting Tier 3 standards due 

to its unique application in the close-coupled-catalyst location required for vehicles 

certifying to very stringent emission standards. Close-coupling means that the 

exhaust catalyst is moved as close as possible to the engine’s exhaust ports within 

the packaging constraints of an engine compartment. This ensures that the catalyst 

reaches its minimal operational, or “light-off”, temperature as quickly as possible 

after the vehicle is started. It also means, however, that the exhaust catalyst(s) in 

the close-coupled location(s) are subject to higher exhaust temperatures during 

fully-warmed up operation. Pd is required in closed-coupled catalysts due to its 

resistance to high-temperature thermal sintering thereby maintaining sufficient 

durability of the emissions control system over the useful life of a vehicle. Sulfur 

removal from Pd requires rich operation at higher temperatures than required for 

sulfur removal from other PGM catalysts.286

In addition to its interaction with catalyst materials, sulfur can also react 

with the wash-coating itself to form alumina sulfate, which in turn can block 

coating pores and reduce gaseous diffusion to active materials below the coating 

 

280 Luo, T. Gorte, R.J. (2003). A Mechanistic Study of Sulfur Poisoning of the Water-Gas-Shift 

Reaction Over Pd/Ceria.” Catalysis Letters, 85, Issues 3-4, pg. 139-146.

281 Li-Dun, A., Quan, D.Y. (1990). “Mechanism of sulfur poisoning of supported Pd(Pt)/Al2O3

catalysts for H2-O2 reaction.” Applied Catalysis 61, Issue 1, pg. 219-234.

282 Waqif, M., Bazin, P., Saur, O. Lavalley, J.C., Blanchard, G., Touret, O. “Study of ceria 

sulfation.” Applied Catalysis B: Environmental 11 (1997) 193-205.

283 Bazin, P., Saur, O. Lavalley, J.C., Blanchard, G., Visciglio, V., Touret, O. “Influence of platinum 

on ceria sulfation.” Applied Catalysis B: Environmental 13 (1997) 265-274.

284 Heck, R.M., Farrauto, R.J. (2002). Chapter 6: Automotive Catalyst in Catalytic Air Pollution 

Control, 2nd Edition. John Wiley and Sons, Inc...

285 Luo, T. Gorte, R.J. (2003) A Mechanistic Study of Sulfur Poisoning of the Water-Gas-Shift 

Reaction Over Pd/Ceria. Catalysis Letters, 85, Issues 3-4, pg. 139-146.

286 Beck, D.D., Sommers, J.W. (1995) Impact of sulfur on the performance of vehicle aged 

palladium monoliths. Applied Catalysis B: Environmental 6, 185-200.
Page 129 of 529

surface (see Figure IV-2).287 This may be a significant mechanism for the observed 

storage of sulfur compounds at light and moderate load operation with subsequent, 

rapid release as sulfate particulate matter emissions when high-load, hightemperature conditions are encountered.288

Operating the catalyst at a sufficiently high temperature under net reducing 

conditions (e.g., air-to-fuel equivalence that is net fuel-rich of stoichiometry) can 

effectively release the sulfur oxides from catalyst components. Thus, regular 

operation at sufficiently high temperatures at net fuel-rich air-to-fuel ratios can 

minimize the effects of fuel sulfur levels on catalyst active materials and catalyst 

efficiency; however, it cannot completely eliminate the effects of sulfur poisoning. 

In current vehicles, desulfurization conditions occur typically at high loads when 

there is a degree of commanded enrichment (i.e., fuel enrichment commanded by

the engine management system primarily for protection of engine and/or exhaust 

system components). A study of Tier 2 vehicles in the in-use fleet recently 

completed by EPA289 shows that emission levels immediately following high 

speed/load operation is still a function of fuel sulfur level for the gasoline used 

following desulfurization. If a vehicle operates on gasoline with less than 10 ppm 

sulfur, exhaust emissions stabilize over repeat FTP tests at emissions near those of 

the first FTP that follows the high speed/load operation and catalyst desulfurization. 

If the vehicle continues to operate on higher sulfur gasoline following 

desulfurization, exhaust emissions creep upward until a new equilibrium exhaust 

emissions level is established. This suggests that lower fuel sulfur levels achieve 

emission benefits unachievable by catalyst desulfurization procedures alone. 

Continued operation on gasoline with a 10 ppm average sulfur content or lower is 

necessary after catalyst desulfurization in order to achieve emissions reductions

with the current in-use fleet.290 Furthermore, regular operation at the high exhaust 

temperatures and rich air-to-fuel ratios necessary for catalyst desulfurization is not 

desirable and may not be possible for future Tier 3 vehicles for several reasons: 

 Thermal sintering and resultant catalyst degradation: The 

temperatures necessary to release sulfur oxides are high enough to 

lead to thermal degradation of the catalyst over time via thermal 

sintering of active materials. Sintering reduces the surface area 

 

287 Beck, D.D., Sommers, J.W. (1995) Impact of sulfur on the performance of vehicle aged 

palladium monoliths. Applied Catalysis B: Environmental 6, 185-200. 

288 Maricq, M. M. Chace, R.E., Xu, N., Podsiadlik, D.H. (2002). The Effects of the Catalytic 

Converter and Fuel Sulfur Level on Motor Vehicle Particulate Matter Emissions: Gasoline 

Vehicles.” Environmental Science and Technology, 36, No. 2 pg. 276-282. 

289 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

290 See Preamble Section IV.A.6.c and Chapter 1 of the RIA (Section 1.2.3.2) for more details on this 

study and its results. 
Page 130 of 529

available to participate in reactions and thus reduces the overall 

effectiveness of the catalyst. 

 Operational conditions: It is not always possible to maintain fuelrich operational conditions and exhaust catalyst temperatures that are 

high enough for sulfur removal because of cold weather, idle 

conditions and light-load operation.

 Increased emissions: In order to achieve greater emission reductions 

across a fuller range of in-use driving conditions, vehicle 

manufacturers’ use of commanded enrichment, which has been

beneficial for sulfur removal, will be greatly reduced or eliminated 

under Tier 3. Additionally, the fuel-rich air-to-fuel ratios necessary

for sulfur removal from active catalytic surfaces would result in 

increased PM, NMOG, CO and air toxic emissions, particularly at 

the high-temperature, high load conditions (e.g., US06 or 

comparable) necessary for sulfur removal. Previously used levels of 

commanded enrichment (e.g., under Tier 2) would interfere with the 

strategies necessary to comply with more stringent Tier 3 SFTP 

exhaust emissions standards. There are also additional provisions 

within the Tier 3 standards that further restrict the use of US06 and 

off-cycle commanded enrichment in an effort to reduce high-load 

and off-cycle PM, NMOG, CO and air toxic emissions.291

 Expected changes to engine performance necessary to reduce fuel 

consumption and greenhouse gas emissions will improve the thermal 

efficiency of engines and may result in reduced exhaust 

temperatures.

b. Previous Studies of Gasoline Sulfur Impacts

This section summarizes studies to provide historical context regarding what 

is known about the direct impacts of gasoline sulfur on vehicle exhaust emissions. 

Reducing fuel sulfur levels has been the primary regulatory mechanism EPA has 

used to minimize sulfur contamination of exhaust catalysts and to ensure optimum 

emissions performance over the useful life of a vehicle. The impact of gasoline 

sulfur on exhaust catalyst systems has become even more important as vehicle 

emission standards have become more stringent. Studies have suggested a 

progressive increase in catalyst sensitivity to sulfur when standards increase in 

stringency and emissions levels decrease. Emission standards under the programs 

 

291 See §86.1811-17 (LD) within the Tier 3 regulations. Tier 3 restrictions to commanded 

enrichment are also discussed in further detail within section IV.A.4.c of this preamble.
Page 131 of 529

that preceded the Tier 2 program (Tier 0, Tier 1, and National LEV, or NLEV) were 

high enough that the impact of sulfur was considered of little importance. The Tier 

2 program recognized the importance of sulfur and reduced the sulfur levels in the 

fuel from around 300 ppm to 30 ppm in conjunction with the new emission 

standards.292 At that time, very little work had been done to evaluate the effect of 

further reductions in fuel sulfur, especially on in-use vehicles that may have some 

degree of catalyst deterioration due to real-world operation or on vehicles with 

extremely low tailpipe emissions as described earlier.

In 2005, EPA and several automakers jointly conducted a research program, 

the Mobile Source Air Toxics (MSAT) Study that examined the effects of sulfur 

and other gasoline properties such as benzene and volatility on emissions from a 

fleet of nine Tier 2 compliant vehicles.293 The study found significant reductions in 

NOX, CO and total hydrocarbons (HC) when the vehicles were tested on low sulfur 

fuel, relative to 32 ppm fuel. In particular, the study found a 48 percent increase in 

NOX over the FTP when gasoline sulfur was increased from 6 ppm to 32 ppm. 

Given the preparatory procedures related to catalyst clean-out and loading used by

these studies, these results may represent a “best case” scenario relative to what 

would be expected under more typical driving conditions. Nonetheless, these data 

suggested the effect of in-use sulfur loading was largely reversible for Tier 2 

vehicles, and that there were likely to be significant emission reductions possible 

with further reductions in gasoline sulfur level. More recently, EPA completed a 

comprehensive study on the effects of gasoline sulfur on the exhaust emissions of 

Tier 2 vehicles at low to moderate mileage levels.294 Further details of this study

are summarized in Section IV.A.6.c of this preamble. 

In the NPRM, we summarized the limited data available regarding the 

impact of gasoline sulfur on the near-zero exhaust emission vehicle technologies 

that will be necessary for Tier 3 compliance. Vehicles certified to California LEV 

II SULEV and PZEV standards and federal Tier 2 Bin 2 standards achieve levels of 

exhaust emissions control consistent with the levels of control that will be necessary

for Tier 3 compliance. While these vehicles represent only a relatively small subset 

(e.g., typically small light-duty vehicles and light-duty trucks with limited GVWR 

or towing utility) of the broad range of vehicles that will need to comply with Tier 3 

standards as part of a fleet-wide average, data on these vehicles provide an 

 

292 Tier 2 Regulatory Impact Analysis, EPA 420-R-99-023, December 22, 1999, last accessed on the 

Internet on 12/04/2013 at the following URL: http://epa.gov/tier2

293 Chapter 6 of the Regulatory Impact Analysis for the Control of Hazardous Air Pollutants from 

Mobile Sources Final Rule, EPA 420-R-07-002, February 2007, last accessed on the Internet on 

12/04/2013 at the following URL: http://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1004LNN.PDF.

294 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.
Page 132 of 529

opportunity to study the impact of gasoline sulfur on near-zero exhaust emission 

technologies and is generally representative of technology that are expected to be 

used with mid-size and smaller light-duty vehicles for Tier 3 compliance. Vehicle 

testing by Toyota (Takei et al.) of LEV I, LEV II ULEV and prototype SULEV 

vehicles showed larger percentage increases in NOX and HC emissions for SULEV 

vehicles as gasoline sulfur increased from 8 ppm to 30 ppm, as compared to other 

LEV vehicles they tested.

295 Ball et al. of Umicore Autocat USA, Inc. studied the 

impact of gasoline fuel sulfur levels of 3 ppm and 33 ppm on the emissions of a 

2009 Chevrolet Malibu PZEV.

296

 Umicore’s testing of the Malibu PZEV vehicle 

showed a pronounced and progressive trend of increasing NOX emissions (referred 

to as “NOX creep”) when switching from a 3 ppm sulfur gasoline to repeated, backto-back FTP tests using 33 ppm sulfur gasoline. The PZEV Chevrolet Malibu, after 

being aged to an equivalent of 150,000 miles, demonstrated emissions at a level 

consistent with the Tier 3 Bin 30 NMOG+NOX standards when operated on 3 ppm 

sulfur fuel and for at least one FTP test after switching to 33 ppm certification fuel. 

Following operation over 2 FTP cycles on 33 ppm sulfur fuel, NOX emissions alone 

were more than double the Tier 3 30 mg/mi NMOG+NOX standard.270 This 

represents a 70% NOX increase between 3 ppm sulfur and 33 ppm sulfur gasolines, 

approximately 2-3 times of what has been previously reported for similar changes 

in fuel sulfur level for Tier 2 and older vehicles.297,298

Both the Umicore and Toyota studies suggest that the emissions from 

vehicles using near-zero exhaust emissions control technology similar to what is 

expected for compliance with the Tier 3 standards are more sensitive to changes in 

gasoline sulfur content at low (sub-30 ppm) sulfur concentrations than technology

used to meet the higher Federal Tier 2 and California LEV II standards. The 

Umicore and Toyota studies clearly indicate that a progressive increase in catalyst 

sensitivity to sulfur continues as exhaust emissions decrease from levels required by

federal Tier 2 and California LEV II emissions standards to the lower levels 

required by Tier 3 emissions standards. In addition, although vehicles with Tier 2 

technology have somewhat less sulfur sensitivity compared to future Tier 3 

vehicles, there is still significant opportunity for further emissions reductions from

the existing in-use fleet by reducing gasoline sulfur content from 30 ppm to 10 ppm. 

The results of recent testing demonstrating the potential for in-use emissions 

reductions from further gasoline sulfur control are summarized in Section IV.A.6.c. 

 

295 Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. (2000). Fuel Property Requirement 

for Advanced Technology Engines. SAE Technical Paper 2000-01-2019. 

296 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300. 

297 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

298 Shapiro, E. (2009). National Clean Gasoline – An Investigation of Costs and Benefits. Published 

by the Alliance of Automobile Manufacturers.
Page 133 of 529

Recent data on the impact of gasoline sulfur on vehicles with exhaust emission 

control technologies that we expect to be used with Tier 3 vehicles is summarized 

in Sections IV.A.6.d and e.

c. EPA Testing of Gasoline Sulfur Effects on Tier 2 Vehicles and the InUse Fleet

Both the MSAT299 and Umicore300 studies showed the emission reduction 

potential of lower sulfur fuel on Tier 2 and later technology vehicles over the FTP 

cycle. However, assessing the potential for reduction on the in-use fleet requires 

understanding how sulfur exposure over time impacts emissions, and what the state 

of catalyst sulfur loading is for the typical vehicle in the field. In response to these 

data needs, EPA conducted a new study to assess the emission reductions expected 

from the in-use Tier 2 fleet with a reduction in fuel sulfur level from current 

levels.

301

 It was designed to take into consideration what was known from prior 

studies on sulfur build-up in catalysts over time and the effect of periodic 

regeneration events that may result from higher speed and load operation over the 

course of day-to-day driving. 

The study sample described in this analysis consisted of 93 cars and light 

trucks recruited from owners in southeast Michigan, covering model years 2007-9 

with approximately 20,000-40,000 odometer miles.302 The makes and models 

targeted for recruitment were chosen to be representative of high sales vehicles 

covering a range of types and sizes. Test fuels were two non-ethanol gasolines with 

properties typical of certification test fuel, one at a sulfur level of 5 ppm and the 

other at 28 ppm. All emissions data was collected using the FTP cycle at a nominal 

temperature of 75 °F.

Using the 28 ppm test fuel, emissions data were collected from vehicles in 

their as-received state as well as following a high-speed/load “clean-out” procedure 

consisting of two back-to-back US06 cycles intended to reduce sulfur loading in the 

catalyst. A statistical analysis of this data showed highly significant reductions in 

 

299 Chapter 6 of the Regulatory Impact Analysis for the Control of Hazardous Air Pollutants from 

Mobile Sources Final Rule, EPA 420-R-07-002, February 2007, last accessed on the Internet on 

12/04/2013 at the following URL: http://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1004LNN.PDF

300 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300

301 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

302 The NPRM modeling was based on analysis of 81 passenger cars and trucks. Since the NPRM, 

twelve additional Tier 2 vehicles were tested and included in the statistical analysis described in the 

docketed final report, examining the effect of sulfur on emissions from Tier 2 vehicles. The analysis 

based on the complete set of 93 Tier 2 vehicles is reflected in the results presented in this section and 

the emissions modeling for FRM.
Page 134 of 529

several pollutants including NOX and hydrocarbons, demonstrating that sulfur 

loadings have a large effect on exhaust catalyst performance, and that Tier 2 

vehicles can achieve significant reductions based on removing, at least in part, the 

negative impact of the sulfur loading on catalyst efficiency (Table IV-6). For 

example, Bag 2 NOX emissions dropped 31 percent between the pre- and postcleanout tests on 28 ppm fuel. 

Table IV-6 Average Clean-out Effect on In-use Emissions Using 28 ppm Test 

Fuela

NOX

(p-value)

THC

(p-value)

CO

(p-value)

NMHC

(p-value)

CH4

(p-value)

PM

(p-value)

Bag 1 – – 6.0% 

(0.0151)

– – 15.4%

(< 

0.0001)

Bag 2 31.4% 

(0.0003)

14.9% 

(0.0118)

– 18.7% 

(0.0131)

14.4% 

(0.0019)

–

Bag 3 35.4% 

(<0.0001)

20.4% 

(<0.0001)

21.5% 

(0.0001)

27.7% 

(<0.0001)

10.3% 

(<0.0001)

24.5% 

(<0.0001)

FTP 

Composite

11.4% 

(0.0002)

3.8% 

(0.0249)

6.8% 

(0.0107)

3.5% 

(0.0498)

6.0% 

(0.0011)

13.7% 

(<0.0001)

Bag 1 – Bag 3 – – 7.2%

(0.0656)

– – –

a The clean-out effect is not significant at α = 0.10 when no reduction estimate is provided.
Page 135 of 529

To assess the impact of lower sulfur fuel on in-use emissions, further testing 

was conducted on a representative subset of vehicles on 28 ppm and 5 ppm fuel 

with accumulated mileage. A first step in this portion of the study was to assess the 

differences in the effectiveness of the clean-out procedure under different fuel 

sulfur levels. Table IV-7 presents a comparison of emissions immediately

following (<50 miles) the clean-out procedures at the low vs. high sulfur level. 

These results show significant emission reductions for the 5 ppm fuel relative to the 

28 ppm fuel immediately after this clean-out; for example, Bag 2 NOX emissions 

were 34 percent lower on the 5 ppm fuel vs. the 28 ppm fuel. This indicates that the 

catalyst is not fully desulfurized, even after a clean out procedure, as long as there is 

sulfur in the fuel. This further indicates that current sulfur levels in gasoline 

continue to have a long-term, adverse effect on exhaust emissions control that is not 

fully removed by intermittent clean-out procedures that can occur in day-to-day

operation of a vehicle and demonstrates that lowering sulfur levels to 10 ppm on 

average will significantly reduce the effects of sulfur impairment on emissions 

control technology. 

Table IV-7: Percent Reduction in Exhaust Emissions When Going from 28 

ppm to 5 ppm Sulfur Gasoline for the First Three Repeat FTP Tests 

Immediately Following Clean-out 

NOX

(p-value)

THC

(p-value)

CO

(p-value)

NMHC

(p-value)

CH4

(p-value)

PMa

Bag 1 5.3%

(0.0513)

6.8%

(0.0053)

6.2%

(0.0083)

5.7%

(0.0276)

14.0%

(<0.0001)

–

Bag 2 34.4%

(0.0036)

33.9%

(<0.0001)

–

a

26.4%

(0.0420)

49.4%

(<0.0001)

–

Bag 3 42.5%

(<0.0001)

36.9%

(<0.0001)

14.7%

(0.0041)

51.7%

(<0.0001)

28.5%

(<0.0001)

–

FTP Composite 15.0%

(0.0002)

13.3%

(<0.0001)

8.5%

(0.0050)

10.9%

(0.0012)

23.6%

(<0.0001)

–

Bag 1 – Bag 3 –

a

–

a

–

a

–

a

–

a

–

a

Sulfur level not significant at α = 0.10. 

To assess the overall in-use reduction between high and low sulfur fuel, a 

mixed model analysis of all data as a function of fuel sulfur level and miles driven 

after cleanout was performed. This analysis found highly significant reductions for 

several pollutants, as shown in Table IV-8. Reductions for Bag 2 NOX were 

particularly high, estimated at 52 percent between 28 ppm and 5 ppm overall. For 

all pollutants, the model fitting did not find a significant miles-by-sulfur interaction, 

suggesting the relative differences were not dependent on miles driven after cleanout. 
Page 136 of 529

Table IV-8 Summary of Mixed Model Results for Emission Reductions When 

Going from 28 ppm to 5 ppm Sulfur Gasoline

NOX

(p-value)

THC

(p-value)

CO

(p-value)

NMHC

(p-value)

CH4

(p-value)

NOX+NMOG

(p-value) PMa

Bag 1 7.1%

(0.0216)

9.2%

(0.0002)

6.7%

(0.0131)

8.1%

(0.0017)

16.6%

(< 0.0001) N/A –

Bag 2 51.9%

(< 0.0001)

43.3%

(< 0.0001) –

a 42.7%

(0.0003)

51.8%

(< 0.0001) N/A –

Bag 3 47.8%

(< 0.0001)

40.2%

(< 0.0001)

15.9%

(0.0003)

54.7%

(< 0.0001)

29.2%

(< 0.0001) N/A –

FTP Composite 14.1%

(0.0008)

15.3%

(< 0.0001)

9.5%

(< 0.0001)

12.4%

(< 0.0001) 29.3%

(< 0.0001)

14.4%

(<.0001)

–

Bag 1 – Bag 3 –

a 5.9%

(0.0074) –

a

–

b

–

b N/A –

a

Sulfur level not significant at α = 0.10. 

b Inconclusive because the mixed model did not converge. 

Major findings from this study include:

 Largely reversible sulfur loading is occurring in the in-use fleet of Tier 2 

vehicles and has a measureable effect on emissions of NOX, 

hydrocarbons, and other pollutants of interest.

 The effectiveness of high speed/load procedures in restoring catalyst 

efficiency is limited when operating on higher sulfur fuel.

 Reducing fuel sulfur levels from current levels to levels in the range of 

the Tier 3 gasoline sulfur standards is expected to achieve significant 

reductions in emissions of NOX, hydrocarbons, and other pollutants of 

interest in the current in-use fleet.

 Assuming that the emissions impacts vs. gasoline sulfur content are 

approximately linear, changing gasoline sulfur content from 30 ppm to 

10 ppm would result in NMOG+NOx emissions decreasing from 52 

mg/mi to 45 mg/mi, respectively (a 13% decrease), and NOx emissions 

decreasing from 19 mg/mi to 16 mg/mi, respectively (a 16% decrease), 

for the vehicles in the study. 
Page 137 of 529

To evaluate the robustness of the statistical analyses assessing the overall inuse emissions reduction between operation on high and low sulfur fuel (Table 

IV-8), a series of sensitivity analyses were performed to assess the impacts on study

results of measurements from low-emitting vehicles and influential vehicles, as 

documented in detail in the report.

303

 The sensitivity analyses showed that the 

magnitude and the statistical significance of the results were not impacted and thus 

demonstrated that the results are statistically robust. We also subjected the design of 

the experiment and data analysis to a contractor-led independent peer-review 

process in accordance with EPA’s peer review guidance. The results of the peer 

review304,305 largely supported the study design, statistical analyses, and the 

conclusions from the program and raised only minor concerns that have not 

changed the overall conclusions and have subsequently been addressed in the final 

version of the report.

306

 

Overall, the reductions found in this study are in agreement with other low 

sulfur studies conducted on Tier 2 vehicles, namely MSAT and Umicore studies 

mentioned above, in terms of the magnitude of NOX and HC reductions when 

switching from 28 ppm to 5 ppm fuel.

307 We have reviewed the results of the 

emission effects study performed by SGS, which was included with API’s 

comments on the Tier 3 proposal, and have concluded that these results are also 

consistent with the findings of EPA’s Tier 2 in-use study, specifically that exhaust 

emissions performance is sensitive to fuel sulfur level.308 The SGS study also 

suggests that negative effects of exposure to a somewhat higher sulfur level (80 

ppm in this case) are largely reversible for Tier 2 vehicles, meaning that reducing 

fuel sulfur levels nationwide will bring significant immediate benefits by reducing 

emissions of the existing fleet. For further details regarding the Tier 2 In-Use 

Gasoline Sulfur Effects Study, see the final report.

309

 

303 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

304 Peer Review of the Effects of Fuel Sulfur Level on Emissions from the In-Use Tier 2 Vehicles,

EPA-HQ-OAR-2011-0135-1847. 

305 EPA In-Use Sulfur Report – Response to Peer-Review Comments, EPA-HQ-OAR-2011-0135-

1848.

306 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

307 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300.

308 American Petroleum Institute. 2013. Supplemental Comments of the American Petroleum 

Institute. Available in the docket for this final rule, docket no. EPA-HQ-OAR-2011-0135

309 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002. 

310 The make and model of the tested vehicles are Honda Crosstour, Chevrolet Malibu, Chevrolet 

Silverado, Ford Focus and Subaru Outback.
Page 138 of 529

As a follow-on phase to the Tier 2 in-use study, EPA analyzed five 

vehicles310 certified to Tier 2 Bin 4, LEV II ULEV and LEV II SULEV exhaust 

emissions standards to assess the gasoline sulfur sensitivity of Tier 2 and California 

LEV II vehicles with emission levels approaching or comparable to the Tier 3 

standards. The analysis found that these low-emitting Tier 2 vehicles showed 

similar or greater sensitivity to fuel sulfur levels compared to the original Tier 2 test 

fleet – for example, a 24 percent reduction in FTP composite NOx emissions when 

sulfur is reduced from 28 ppm to 5 ppm.311 Test results discussed below in section 

IV.A.6.d also confirm that there is significantly increased sensitivity of exhaust 

emissions to gasoline sulfur as vehicle technologies advance towards exhaust 

emissions approaching near-zero emissions (e.g., Tier 3 Bin 50 and lower). The 

impact of fuel sulfur on vehicles with exhaust emission control technologies that we 

expect to be used with Tier 3 vehicles is summarized in the next two sections 

(Preamble IV.A.6.d and e). 

EPA believes that the studies by EPA and others described in this section 

strongly support our conclusion that reducing gasoline sulfur content to a 10 ppm 

average will result in significant exhaust emissions reductions from the current inuse fleet. However, some commenters have expressed concerns about the relevance 

and appropriateness of the data, as well as the conclusions drawn from them. The 

Summary and Analysis of Comments document, available in the docket for this 

rulemaking, provides our responses to those comments.

d. Testing of Gasoline Sulfur Effects on Vehicles with Tier 3/LEV III 

Technology

The Tier 3 fleet average exhaust emissions standards of 30 mg/mi 

NMOG+NOx will require large reductions of emissions across a broad range of 

light-duty vehicles and trucks with differing degrees of utility. Previous studies of 

sulfur impacts on extremely low exhaust emission vehicles (e.g., Toyota, Umicore) 

were limited to mid-size or smaller light-duty vehicles. There are currently no

LDT3 or any LDT4 vehicles certified at or below Federal Tier 2 Bin 3 or to the

California LEV II SULEV exhaust emission standards with the exception of a 

single hybrid electric SUV. At the time of the Tier 3 NPRM, EPA was not aware of 

any existing data demonstrating the impact of changes in gasoline sulfur content on 

larger vehicles with technology comparable to what would be expected for 

compliance with Tier 3 exhaust emission standards. In their supplemental 

comments to the Tier 3 proposal, API criticized EPA’s reliance on emissions data 

from older vehicles that were not considered to be examples of future Tier-3-like 

 

310 The make and model of the tested vehicles are Honda Crosstour, Chevrolet Malibu, Chevrolet 

Silverado, Ford Focus and Subaru Outback.

311 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.
Page 139 of 529

vehicles. In order to further evaluate this issue, the Agency initiated a test program 

at EPA’s National Vehicle and Fuel Emissions Laboratory (NVFEL) in Ann Arbor, 

Michigan. The Agency obtained a heavy-light-duty truck and applied changes to the 

design and layout of the exhaust catalyst system and to the calibration of the engine 

management system consistent with our engineering analyses of technology 

necessary to meet Tier 3 Bin 30 emissions with a 20 to 40% compliance margin at 

150,000 miles. EPA also requested that Umicore loan the Agency the vehicle tested 

in their study to undergo further evaluation of gasoline sulfur impacts on exhaust 

emissions. In addition, Ford Motor Company completed testing of fuel sulfur 

effects on a Tier 3/LEV III developmental heavy-light-duty truck and submitted a 

summary report of their findings as part of their supplemental comments to the Tier 

3 NPRM. The results of these three test programs are summarized below. 

i. Ford Motor Company Tier 3 Sulfur Test Program

Ford Motor Company recently completed testing of a heavy-light-duty truck 

(i.e., between 6000 and 8500 pounds GVWR) under development to meet the Tier 3 

Bin 50 standards on two different fuel sulfur levels and submitted the resulting data 

to EPA as part of its supplemental comments. 312,313 The test results from this 

vehicle are particularly important when considering the following factors:

 These are the first detailed emissions data submitted by a vehicle 

manufacturer to the Agency demonstrating emissions of a heavylight-duty-truck consistent with Tier 3 Bin 50 or lower emissions 

levels.

 The truck tested uses a version of Ford’s 2.0 L GTDI engine, an 

engine with high BMEP (approximately 23-bar) that can allow 

significant engine displacement downsizing while maintaining the 

truck’s utility. This is a key enabling GHG reduction strategy

analyzed by EPA in the 2017-2025 GHG Final Rule.314 

 

312 Ford Motor Company. 2013. “Quality Changes Needed to Meet Tier 3 Emission Standards and 

Future Greenhouse Gas Requirements.” Attachment 2: “Tier 3 Sulfur Test Program – Ford Motor 

Company Summary Report.” Available within EPA Docket for this final rule, EPA-HQ-2011-0135.

313 Dominic DiCicco, Ford Motor Company. 2013. “Additional data as requested. RE: Ford 

Supplemental Comments on Tier 3.” Available within EPA Docket for this final rule, EPA-HQ2011-0135.

314 See 77 FR 62840-62862, October 15, 2012; and Joint Technical Support Document: Final 

Rulemaking for 2017-2025 Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate 

Average Fuel Economy Standards (EPA-420-R-12-901), August 2012, Chapter 3.4.1.7 - 3.4.1.8 

(pages 3-88 – 3-95).
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 The vehicle was specifically under development by a vehicle 

manufacturer with an engineering target of meeting Tier 3 Bin 50 

and LEV III ULEV50 exhaust emissions standards.

Turbocharged, downsized engines are key technologies within Ford’s strategy to 

reduce GHG emissions.315 EPA expects that trucks with configurations similar to 

this developmental Ford Explorer (downsized engines with reduced GHG emissions

and very low emissions of NMOG+NOx) will become increasingly prevalent within 

the timeframe of the implementation of the Tier 3 regulations. 

The developmental truck used close-coupling of both catalyst substrates and 

relatively high PGM loading (150 g/ft3). Ford used accelerated aging of the 

catalysts and O2 sensors to an equivalent of 150,000 miles (the Tier 3 full useful 

life). The developmental hardware and engine management calibration 

configuration of this truck was designed to meet federal Tier 3 Bin 50 and 

California LEV III ULEV50 standards of 50 mg/mi NMOG+NOx at 150,000 miles. 

The emissions data submitted by Ford included NOx and NMHC emissions during 

operation on E10 California LEV III certification fuel at two different sulfur levels, 

10 ppm and 26.5 ppm. Ford did not provide NMOG emissions data but there was 

sufficient information for EPA to calculate NMOG emissions from the provided 

NMHC data using calculations from Title 40 CFR § 1066.665. 

The truck demonstrated average FTP NMOG+NOx emissions of 37 mg/mi 

on the 10 ppm E10 California LEV III fuel, emissions that are consistent with 

compliance with Bin 50 and ULEV50 standards with a reasonable margin of 

compliance (emissions at approximately 70% of the standard). Retesting of the 

same vehicle on LEV3 E10 blended316 to 26.5 ppm S resulted in average 

NMOG+NOx emissions of 53 mg/mi, 6% above the Tier 3 Bin 50 standard. Ford 

found a high level of statistical significance with respect to the increase of 

emissions with increasing fuel sulfur. Assuming a linear effect of sulfur on 

emissions performance, NMOG+NOx emissions would be approximately 56 mg/mi 

at 30 ppm sulfur, which is approximately 12% above the Bin 50 exhaust emissions 

standard. This also represents an increase in NMOG+NOx emissions of 53% with 

an approximate doubling of NOx emissions and a 13 % increase in NMOG for 30 

ppm sulfur gasoline vs. 10 ppm sulfur gasoline.

 

315 Ford Motor Company, 2012. “Sustainability 2011/2012 – Improving Fuel Economy.” Accessed 

on the Internet on 11/21/2013 at: http://corporate.ford.com/microsites/sustainability-report-2011-

12/environment-products-plan-economy. Available within EPA Docket for this final rule, EPA-HQ2011-0135.

316 Ford used the same tert-butyl sulfide fuel sulfur additives used within the EPA testing in IV.A.6.c 

and d.
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The advanced technology Ford truck, which was shown to be capable of 

complying with the Tier 3 Bin 50 standard with a reasonable margin of compliance 

on 10 ppm sulfur gasoline, in effect reverted to approximately LEV II ULEV 

exhaust emissions levels when tested on higher sulfur gasoline, equivalent to the

previous level of emissions control to which earlier models of this vehicle were 

certified for MY 2013. The effect of increasing gasoline sulfur levels from 10 ppm 

to 30 ppm317 on this vehicle essentially negated the entire benefit of the advances in 

emissions control technology that were applied by the vehicle manufacturer to meet 

developmental goals for compliance with Tier 3 standards. This clearly indicates, 

for this vehicle model using technology representative of what would be expected 

for compliance with Tier 3 Bin 50 and post 2017 GHG standards, reducing gasoline 

sulfur to 10 ppm is needed for the advances in technology to achieve their intended 

effectiveness in reducing NMOG+NOx emissions. The advances in vehicle 

technology and the reduction in gasoline sulfur clearly are both needed to achieve 

the emissions reductions called for by Tier 3. 

ii. EPA Re-test of Umicore 2009 Chevrolet Malibu PZEV

Ball et al. of Umicore Autocat USA, Inc. previously studied the impact of 

gasoline fuel sulfur levels of 3 ppm and 33 ppm on the emissions of a 2009 

Chevrolet Malibu PZEV.318 In their supplemental comments, API commented that 

the composition of the two test fuels outside of sulfur content was not held constant

and thus the exhaust emissions differences attributed to the difference in gasoline 

sulfur levels may have been due to other fuel property differences. For example, the 

3 ppm fuel used by Ball et al. was nonoxygenated EEE Clear test fuel (essentially, 

Tier 2 Federal certification gasoline except with near-zero sulfur) while the 33 ppm 

fuel was an oxygenated California Phase 2 LEV II certification fuel. Thus it was

not entirely clear if the changes in NOx emissions observed between tests with the 

two fuels were significantly impacted by fuel composition variables other than 

gasoline sulfur content. EPA obtained the same test vehicle from Umicore for 

retesting at the EPA NVFEL facility using the 5 ppm and 28 ppm sulfur E0 test 

fuels and vehicle test procedures used in EPA gasoline sulfur effects testing on Tier 

2 vehicles (see Section IV.6.b). 

In EPA’s retest of the 2009 Chevrolet Malibu PZEV, when sulfur was the 

only difference between the test fuels, the gasoline with higher sulfur resulted in 

significantly higher increases in NOx emissions with increasing fuel sulfur content 

than was observed in the previous testing by Ball et al. at Umicore. Assuming 

 

317Emissions at 30 ppm sulfur estimated assuming approximately linear emissions effects between 

10, 26.5 and 30 ppm gasoline sulfur levels.

318 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300. Available in the docket for this 

final rule.
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emissions impacts vs. gasoline sulfur content are approximately linear, the original 

data from Ball et al. would have resulted in a predicted increase in NOx emissions 

of approximately 40% when increasing gasoline sulfur from 10 ppm to 30 ppm. 

The EPA re-testing of the same vehicle that controlled for other fuel composition 

differences resulted in a predicted increase in NOx emissions of 93% when 

increasing gasoline sulfur from 10 ppm to 30 ppm, with NOx emissions 

approximately doubling from 22 g/mi to 43 g/mi, with no statistically significant 

difference in NMOG emissions and with an increase in NMOG+NOx emissions of 

56%. The approximate doubling in NOx emissions with the Malibu PZEV between 

10 ppm and 30 ppm sulfur was nearly identical to the results found during testing of 

the Tier 3 Bin 50 developmental Ford Explorer discussed above. The results 

confirm that fuel compositional differences other than sulfur may have impacted 

exhaust emissions results in the Ball et al. study by underreporting a substantial 

portion of the effect of increased sulfur on NOx emissions. When controlling for 

other fuel composition differences, the resultant increase in NOx exhaust emissions

due to increasing gasoline sulfur was more than double that observed in the original 

Ball et al. study. The observed increase in NMOG+NOx emissions during EPA 

testing of the Malibu PZEV was also comparable to results found with the 

developmental Tier 3 Bin 50 Ford Explorer. There was also a much higher increase 

in NOx and NMOG+NOx emissions for both the Malibu PZEV and the Tier 3 Bin

50 Explorer with increased gasoline sulfur than was observed with Tier 2 vehicles

in the EPA Tier 2 in-use study. (See also Chapter 1.2.4 of the RIA) 

iii.EPA Prototype Tier 3 Heavy-light-duty Truck Test Program

EPA purchased a 2011 Chevrolet Silverado heavy-light-duty (LDT4) pickup 

truck with a developmental goal of modifying the truck to achieve exhaust 

emissions consistent with compliance with the Tier 3 Bin 30 emissions standards. 

The truck was equipped with a 5.3L V8 with General Motors’ “Active Fuel 

Management” cylinder deactivation system. This particular truck was chosen in 

part because cylinder deactivation is a key technology for light-truck compliance 

with future GHG standards and in part because it achieved very low emissions in its 

OEM, Tier 2-compliant configuration (certified to Tier 2 Bin 4). A prototype 

exhaust system was obtained from MECA consisting of high-cell-density (900 cpsi) 

thin-wall (2.5 mil), high-PGM, close-coupled Pd-Rh catalysts with an additional 

under-body Pd-Rh catalyst. The total catalyst volume was approximately 116 in3

with a specific PGM loading of 125 g/ft3and approximate loading ratio of 0:80:5 

(Pt:Pd:Rh). Third-party (non-OEM) EMS calibration tools were used to modify the 

powertrain calibration in an effort to improve catalyst light-off performance. The 

final test configuration used approximately 4 degrees of timing retard and 

approximately 200 rpm higher idle speed relative to the OEM configuration during 

and immediately following cold-start. The exhaust catalyst system and HEGO 
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sensors were bench aged to an equivalent 150,000 miles using standard EPA 

accelerated catalyst bench-aging procedures.320 The truck was tested on California 

LEV III E10 certification fuel at 9 and 29 ppm gasoline sulfur levels.

The EPA Tier 3 prototype Silverado achieved NMOG+NOx emissions of 18 

mg/mi on the 9 ppm S fuel. The NMOG+NOx emissions were approximately 60% 

of the Bin 30 standard and thus are consistent with meeting the Tier 3 Bin 30 

exhaust emissions standard with a moderate compliance margin. NMOG+NOx 

emissions increased to 29 mg/mi on the 29 ppm S fuel and one out of four tests 

exceeded the Bin 30 exhaust emissions standards. NMOG+NOx emissions would 

be at 19 mg/mi and 30 mg/mi with 10 ppm and 30 ppm gasoline sulfur, 

respectively, assuming a linear effect of sulfur on emissions performance. This 

represents an increase in NMOG+NOx emissions of approximately 55%, 

comparable to increases observed with both the EPA-tested Chevrolet Malibu 

PZEV and the developmental Tier 3 Bin 50 Ford Explorer. The impact of increased 

gasoline sulfur on NMOG+NOx emissions was due to comparable increases (on a 

percentage basis) in both NMOG and NOx emissions. This effect of gasoline sulfur 

on the Prototype Silverado truck’s emissions differed from the sulfur impacts 

observed on the developmental Ford Explorer, which primarily affected NOx 

emissions, and the Malibu PZEV, where the impact was entirely on NOx emissions. 

e. Gasoline Sulfur Level Necessary for New Light-duty Vehicles to 

Achieve Tier 3 Exhaust Emissions Standards

Meeting Tier 3 NMOG+NOx standards will require major reductions in 

exhaust emissions across the entire fleet of new light-duty vehicles. As discussed in 

previous sections, the Tier 3 program will require reductions in fleet average 

NMOG+NOx emissions of over 80 percent for the entire fleet of light-duty vehicles 

and light-duty trucks. This significant level of fleet average emission reduction will 

require reductions from all parts of the fleet, including vehicles models with exhaust 

emissions currently at or near the level of the fully phased-in Tier 3 FTP 

NMOG+NOx fleet average standard of 30 mg/mi.

Compliance with the more stringent Tier 3 fleet average standards will 

require vehicle manufacturers to certify a significant amount of vehicles to bin 

standards that are below the Bin 30 fleet average standard to offset other vehicles 

that are certified to bin standards that remain somewhat above the Bin 30 fleet 

average even after significantly reducing their emissions. At the same time, the 

stringency of the Tier 3 standards will push almost all vehicle models to be close to 

or below the Bin 30 fleet average standard. There are only 2 compliance bins 

 

320 U.S. Code of Federal Regulations, Title 40, §86.1823–08 “Durability demonstration procedures 

for exhaust emissions.”
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below Bin 30, i.e., Bin 20 and Bin 0, available to offset emissions of vehicles 

certifying above Bin 30. There is also very limited ability for vehicle 

manufacturers to certify vehicles below the stringent Tier 3 fleet average exhaust 

emissions standard since Bin 20 and Bin 30 standards for individual vehicle 

certification test groups are approaching the engineering limits of what can be 

achieved for vehicles using an internal combustion engine and Bin 0 can only be 

achieved by electric-only vehicle operation. The result is that there is a very limited 

ability to offset sales of vehicles certified above the 30 mg/mi fleet average 

emission standard. This means in general that vehicle models currently with higher 

emissions will have to achieve significant emissions reductions to minimize the 

gap, if any, between their certified bin levels under Tier 3 and the Tier 3 Bin 30 

fleet average standard, and vehicle models currently at or below Bin 30 will also 

have to achieve further emissions reductions under Tier 3 to offset the vehicles that 

remain certified to bin standards somewhat above Bin 30l. The end result is a need 

for major reductions from all types of vehicles in the light-duty fleet, including 

those above as well as most vehicles that are already near, at, or below the Tier 3 

Bin 30 fleet average standard.

Achieving exhaust emissions reductions of over 80% for the fleet, with 

major reductions across all types of light-duty vehicles and light-duty trucks, will be 

a major technological challenge. Vehicles already have made significant advances 

in controlling cold start emissions and maximizing exhaust catalyst efficiency (e.g.,

improving warm-up and catalyst light-off after cold starts and maintaining very

high catalyst efficiency once warmed up) in order to meet Tier 2 and LEV II 

emissions standards. There are no “low-hanging fruit” remaining for additional 

NMOG+NOx reductions from light-duty vehicles from a technology perspective, 

meaning that vehicle manufacturers cannot merely change one aspect of emissions 

control and thereby achieve all of the required reductions. Instead, compliance with 

light-duty Tier 3 exhaust emissions standards will require significant improvements 

in all areas of emissions control – with further improvements in fuel-system 

management and mixture preparation during cold start, improvements in achieving 

catalyst light-off immediately after cold start, and improved catalyst efficiency

during stabilized, fully-warmed-up conditions. Manufacturers will need further 

improvements in each of these areas with nearly every vehicle in order to comply

with the fleet-average Tier 3 standards. 

From a technology perspective, the most likely control strategies will 

involve using exhaust catalyst technologies and powertrain calibration primarily

focused on reducing cold-start emissions of NMOG, and on reducing both coldstart and warmed-up (running) emissions of NOX. An important part of this 

strategy, particularly for larger vehicles having greater difficulty achieving coldstart NMOG emissions control, will be to reduce NOX emissions to near-zero 

levels. This will involve controlling engine-out NOx emissions during cold start, 

shortening the cold start period prior to catalyst light-off of NOx reduction 

reactions, and better controlling NOx emissions once the catalyst is fully warmed 
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up. This is needed to allow a sufficient NMOG compliance margin so that vehicles 

can meet the combined NMOG+NOX emissions standards for their full useful life.

While significant NMOG+NOx emissions reductions can be achieved from 

better control of cold start NMOG emissions, there are practical engineering limits 

to NMOG control for larger displacement vehicles (e.g., large light-duty trucks with 

significant payload and trailer towing capabilities). This is based in part on the 

impact on NMOG emissions of the larger engine surface-to-volume ratio and 

resultant heat conduction from the combustion chamber during warm-up. There are 

also tradeoffs between some cold-start NMOG controls and cold-start NOx control. 

For example, secondary air injection and/or leaner fueling strategies improve 

catalyst light-off for NMOG after a cold-start but also place OSC components in an 

oxidation state that limits potential for NOx reduction and thus often result in higher 

cold-start NOx emissions. Some applications achieve lower NMOG+NOx 

emissions without the use of secondary air injection by careful calibration, changes 

to the catalyst formulation and balancing of catalyst HC and NOx activity. The 

EPA Prototype Silverado and the developmental Ford Explorer are specific 

examples of this approach. 

Because of engineering limitations with large vehicles, heavy-light-trucks 

and other vehicles with significant utility, we expect many applications will need 

close to 100% efficiency in NOx control under fully warmed-up conditions and 

very fast light-off of NOx reduction reactions over the exhaust catalyst almost 

immediately after cold-start for those applications. This will require significant 

improvements in catalytic and engine-out NOx reduction compared with Tier 2 

vehicles and will be especially important for heavier vehicles due to the challenges 

of achieving low NMOG. 

These technology improvements - improving warm-up and catalyst light-off 

after cold starts and maintaining very high catalyst efficiency - - once warmed up –

all rely on 10 ppm average sulfur fuel to achieve the very significant emissions 

reductions required for the fleet to achieve the Tier 3 Bin 30 fleet average emissions 

standard. The evidence from the test results and specific vehicle examples 

discussed above clearly indicate that leaving the gasoline sulfur level at 30 ppm 

would largely negate the benefits of key technology improvements expected to be 

used for compliance with Tier 3 exhaust emissions standards. Without the lower 10 

ppm gasoline sulfur content, the Tier 3 exhaust fleet average emissions standards 

would not be achievable across the broad range of vehicles that must achieve 

significant exhaust emissions reductions. 

One aspect of the need for sulfur levels of 10 ppm average stems from the 

fact that achieving the Tier 3 emission standards will require very careful control of 

the exhaust chemistry and exhaust temperatures to ensure high catalyst efficiency. 

The impact of sulfur on OSC components in the catalyst makes this a challenge 

even at relatively low (10 ppm) gasoline sulfur levels. NOX conversion by exhaust 
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catalysts is strongly influenced by the OSC components like ceria. Ceria sulfation 

may play an important role in the large degradation of NOX emission control with 

increased fuel sulfur levels observed in the MSAT, Umicore and EPA Tier 2 In-Use 

Gasoline Sulfur Effects studies and the much more severe NOx emissions 

degradation observed in recent test data from PZEV and prototype/developmental 

Tier 3/LEV III vehicles. 321

The importance of lower sulfur gasoline is also demonstrated by the fact that 

vehicles certified to California SULEV are typically certified to higher bins for the 

federal Tier 2 program. Light-duty vehicles certified to CARB SULEV and federal 

Tier 2 Bin 2 exhaust emission standards accounted for approximately 3.1 percent 

and 0.4 percent, respectively, of vehicle sales for MY2009. Light-duty vehicles 

certified to SULEV under LEV II are more typically certified federally to Tier 2 

Bin 3, Bin 4 or Bin 5, and vehicles certified to SULEV and Tier 2 Bins 3-5 

comprised approximately 2.5 percent of sales for MY2009. In particular, nonhybrid 

vehicles certified in California as SULEV are not certified to federal Tier 2 Bin 2 

emissions standards even though the numeric limits for NOX and NMOG are shared 

between the California LEV II and federal Tier 2 programs for SULEV and Bin 2. 

Confidential business information shared by the auto companies indicate that the 

primary reason is an inability to demonstrate compliance with SULEV/Bin 2 

emission standards after vehicles have operated in-use on gasoline with greater than 

10 ppm sulfur and with exposure to the higher sulfur gasoline sold nationwide.

While vehicles certified to the LEV II SULEV and Tier 2 Bin 2 standards both 

demonstrate compliance using certification gasoline with 15-40 ppm sulfur content, 

in-use compliance of SULEV vehicles in California occurs after significant, 

sustained operation on gasoline with an average of 10 ppm sulfur and a maximum 

cap of 30 ppm sulfur while federally certified vehicles under the Tier 2 program

operate on gasoline with an average of 20 ppm sulfur and a maximum cap of 80 

ppm sulfur. Although the SULEV and Tier 2 Bin 2 standards are numerically

equivalent, the increased sulfur exposure of in-use vehicles certified under the 

federal Tier 2 program results in a need for a higher emissions compliance margin 

to take into account the impact of in-use gasoline sulfur on full useful life vehicle 

emissions. As a result, vehicles certified to California SULEV typically certify to 

emissions standards under the federal Tier 2 program that are 1-2 certification bins 

higher (e.g., SULEV certified federally as Tier 2 Bin 3 or Bin 4) in order to ensure 

in-use compliance with emissions standards out to the full useful life of the vehicle 

when operating on higher-sulfur gasoline.

There are currently no LDTs larger than LDT2 with the exception of a 

single hybrid electric SUV certified to Tier 2 Bin 2 or SULEV emissions standards. 

 

321 Heck, R.M., Farrauto, R.J. (2002). Chapter 6: Automotive Catalyst in Catalytic Air Pollution 

Control, 2nd Edition. John Wiley and Sons, Inc.
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We expect that additional catalyst technologies, for example increasing catalyst 

surface area (volume or substrate cell density) and/or increased PGM loading, will 

need to be applied to larger vehicles in order to achieve the catalyst efficiencies 

necessary to comply with the Tier 3 standards, and any sulfur impact on catalyst 

efficiency will have a larger impact on vehicles and trucks that rely more on very 

high catalyst efficiencies in order to achieve very low emissions. The vehicle 

emissions data referenced in Section IV.A.6.d represents the only known data on 

non-hybrid vehicles spanning a range from mid-size LDVs to heavy-light-trucks at 

the very low criteria pollutant emissions levels that will be needed to comply with 

the Tier 3 exhaust emissions standards. The developmental Ford Explorer, 

Chevrolet Malibu PZEV and EPA prototype Chevrolet Silverado vehicles described 

in section IV.A.6.c also represent a range of different technology approaches to 

both criteria pollution control and GHG reduction (e.g., use of secondary air vs. 

emphasizing cold-start NOx control, use of engine downsizing via turbocharging 

vs. cylinder deactivation for GHG control, etc.) and represent a broad range of 

vehicle applications and utility (mid-size LDV, LDT3, LDT4). All of the vehicles 

with Tier 3/LEV III technology demonstrated greater than 50% increases in 

NMOG+NOx emissions when increasing gasoline sulfur from 10 ppm to 30 ppm. 

Two of the vehicles showed a doubling of NOx emissions when increasing gasoline 

sulfur from 10 ppm to 30 ppm. Both of the heavy-light-duty trucks with specific 

engineering targets of meeting Tier 3 emissions were capable of meeting their 

targeted emission standards with a sufficient compliance margin on 10 ppm sulfur 

gasoline and could not meet their targeted emissions standards or could not achieve 

a reasonable compliance margin when tested with 30 ppm sulfur gasoline. 

The negative impact of gasoline sulfur on catalytic activity and the resultant 

loss of exhaust catalyst effectiveness to chemically reduce NOX and oxidize NMOG 

occur across all vehicle categories. However, the impact of gasoline sulfur on the 

effectiveness of exhaust catalysts to control NOX emissions in the fully-warmed-up 

condition is particularly of concern for larger vehicles (the largest LDVs and 

LDT3s, LDT4s, and MDPVs). Manufacturers face the most significant challenges 

in reducing cold-start NMOG emissions for these vehicles. Because of the need to 

reach near-zero NOX emissions levels in order to offset engineering limitations on 

further NMOG exhaust emissions control with these vehicles, any significant 

degradation in NOX emissions control over the useful life of the vehicle would

likely prevent some if not most larger vehicles from reaching a combined 

NMOG+NOX level low enough to comply with the 30 mg/mi fleet-average 

standard. Any degradation in catalyst performance due to gasoline sulfur would

reduce or eliminate the margin necessary to ensure in-use compliance with the Tier 

3 emissions standards. Certifying to a useful life of 150,000 miles versus the 

current 120,000 miles will further add to manufacturers’ compliance challenge for 

Tier 3 large light trucks (See Section IV.A.7.c below for more on the useful life 

requirements.) These vehicles represent a sufficiently large segment of light-duty

vehicle sales now and for the foreseeable future such that their emissions could not 
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be sufficiently offset (and thus the fleet-average standard could not be achieved) by

certifying other vehicles to bins below the fleet average standard. 

As discussed above, achieving Tier 3 levels as an average across the lightduty fleet will require fleet wide reductions of approximately 80%. This will 

require significant reductions from all light duty vehicles, with the result that some 

models and types of vehicles will be at most somewhat above the Tier 3 level, and 

all other models will be at or somewhat below Tier 3 levels. Achieving these 

reductions presents a major technology challenge. The required reductions are of a 

magnitude that EPA expects manufacturers to employ advances in technology in all 

of the relevant areas of emissions control – reducing engine-out emissions, reducing 

the time to catalyst lightoff, improving exhaust catalyst durability at 120,000 or 

150,000 miles and improving efficiency of fully warmed up exhaust catalysts. All 

of these areas of emissions control need to be improved, and gasoline sulfur 

reduction to a 10 ppm average is a critical part of achieving Tier 3 levels through 

these emissions control technology improvements. 

The use of 10 ppm average sulfur fuel is an essential part of achieving Tier 3 

levels while applying an array of advancements in emissions control technology to 

the light-duty fleet. The testing of Tier 2 and Tier 3 type technology vehicles, as 

well as other information, shows that sulfur has a very large impact on the 

effectiveness of the control technologies expected to be used in Tier 3 vehicles. 

Without the reduction in sulfur to a 10 ppm average, the major technology

improvements projected under Tier 3 would only result in a limited portion of the 

emissions reductions needed to achieve Tier 3 levels. For example, without the 

reduction in sulfur from a 30 ppm to 10 ppm average, the technology improvements 

would not come close to achieving Tier 3 levels. In some cases this may result in 

the same effectiveness as the current Tier 2 technology and achieve only

approximately Tier 2 levels of exhaust emissions control. 

Achieving Tier 3 levels without a reduction in sulfur to 10 ppm levels would 

only be possible if there were technology improvements significantly above and 

beyond those discussed above. Theoretically, without reducing sulfur levels to 10 

ppm average, emissions control technology improvements would need to provide 

upwards of twice as much, and in some cases significantly more than twice as 

much, emissions control effectiveness as the Tier 3 technology improvements 

discussed above in Section IV.A.6.d. EPA has not identified technology

improvements that could provide such a large additional increase in emissions 

control effectiveness, across the light-duty fleet, above and beyond that provided by

the major improvements in technology discussed above, without any additional 

gasoline reductions in gasoline sulfur content. The impact of sulfur reduction on 

the effectiveness of the available technology improvements plays such a large role 

in achieving the Tier 3 levels that there would be no reasonable basis to expect that

technology would be available, at the 30 ppm sulfur level, to fill the emission 

control gap left from no sulfur reduction, and achieve the very significant fleetwide 
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reductions needed to meet the Tier 3 fleet average standards. In effect reducing 

sulfur from 30 ppm to 10 ppm has such a large impact on the ability of the 

technology improvements to achieve Tier 3 emissions levels that absent these sulfur 

reductions there is not a suite of technology advancements available to fill the 

resulting gap in emissions reductions. We cannot identify a technology path for 

vehicles that would achieve the Tier 3 Bin 30 average standard, across the fleet, 

with sulfur at 30 ppm levels, and as a result Tier 3 levels would not be technically

feasible and achievable. 

This analysis also applies to gasoline sulfur levels between 10 and 30 ppm, 

e.g., 20 ppm. The Tier 3 required emissions reductions are so large and widespread 

across the fleet, and the technology challenges are sufficiently high, especially for 

heavier vehicles, that the large increase in emissions that would occur from a higher 

average sulfur level compared to a 10 ppm average would lead to an inability for 

vehicle technologies to widely achieve Tier 3 levels as a fleet wide average in order 

to meet the Bin 30 fleet average standard.

EPA acknowledges that some models in the light-duty fleet, when viewed in 

isolation, may be able to achieve Tier 3 levels at current sulfur levels of 30 ppm 

average. Under the Tier 3 fleet average standards, it is not sufficient for one or a 

few of a manufacturer’s vehicle models to meet Tier 3 levels because the 

manufacturer’s light-duty vehicle fleet as a whole must achieve the Tier 3 30 mg/mi

exhaust emissions standard as a fleet-wide average. As discussed above, all vehicle 

models will need to achieve further reductions and be either below or no more than 

somewhat above Tier 3 levels to achieve the Tier 3 standard as a fleet wide average. 

Absent the reductions in sulfur levels to 10 ppm average, this is not achievable from 

a technology perspective.

 As discussed in Section V.B, the average 10 ppm gasoline sulfur standard 

is feasible and is the level that appropriately balances costs with the emission 

reductions that it provides and enables. Not only will a 10 ppm sulfur standard 

enable vehicle manufacturers to certify their entire product line of vehicles to the 

Tier 3 fleet average standards, but reducing gasoline sulfur to 10 ppm will better 

enable these vehicles to maintain their emission performance in-use over their full

useful life. Higher sulfur levels would make it impossible for vehicle 

manufacturers to meet the Tier 3 standards, and would forego the very large 

immediate reductions from the existing fleet. Reducing the sulfur level below 10 

ppm would further reduce vehicle emissions and allow the Tier 3 vehicle standards 

to be achieved more easily. However, we believe that a 10 ppm average standard is 

sufficient to allow vehicles to meet the Tier 3 standards. Further, as discussed in 

Sections V.B and IX.B there are significant challenges associated with reducing 

sulfur below 10 ppm. 
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7. Other Provisions

a. Early Credits

The California LEV III program is scheduled to begin at least two model 

years earlier than the federal Tier 3 program.322 The Tier 3 standards begin in MY 

2017 for vehicles 6,000 lbs GVWR and less, and in MY 2018 for vehicles over 

6,000 lbs GVWR. As a result, LEV III vehicles sold in California beginning in MY 

2015 will be required to meet a lower fleet average NMOG+NOX level than the 

federal fleet will be meeting at that time. In addition, the California NMOG+NOX

standards will further decline before Tier 3 begins, resulting in the gap growing 

between the current federal program and LEV III. 

We are finalizing an early credit program that with minor revisions is as we 

proposed. We have designed the early credit provisions to accomplish three goals: 

(1) to encourage manufacturers to produce a cleaner federal fleet earlier than 

otherwise required; (2) to provide valuable flexibility to the manufacturers to

facilitate the significant “step down” from the current Tier 2 Bin 5 fleet average 

required in MY 2016 to the LEV III-based declining fleet average in MY 2017; and 

(3) to create an overall Tier 3 program that although starts later, is equivalent in 

stringency to the LEV III program such that manufacturers will be able to produce a 

50-state fleet at the earliest opportunity. Commenters were generally supportive of 

or silent on the early credits program as proposed. 

The early credit program we are finalizing includes several distinct 

provisions. The first provision allows manufacturers to generate early federal 

credits against the current Tier 2 Bin 5 requirement323 in MYs 2015 and 2016 for 

vehicles under 6,000 lbs GVWR and MYs 2016 and 2017 for vehicles greater than 

6,000 lbs GVWR. Early credits will only be available to manufacturers that comply

under the primary program (declining fleet average), not the alternative phase-in 

approach (Section IV.A.2.c above). In order to generate these credits, 

manufacturers sum the bin specific NMOG and NOX certification standards for 

each federally certified Tier 2 vehicle and the bin NMOG+NOX standards for any

vehicle certified under the Early Tier 3 provision described below and calculate an 

NMOG+ NOX fleet average for the entire manufacturers fleet sold in a model year. 

Credits are based on how far the fleet average is below the existing Tier 2 Bin 5 

 

322 See California Low-Emission Vehicles (LEV) & GHG 2012 regulations adopted by the State of 

California Air Resources Board, March 22, 2012, Resolution 12-21 incorporating by reference 

Resolution 12-11, which was adopted January 26, 2012. Available at 

http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm (last accessed December 2, 

2013).

323 Tier 2 standards are not set in the form of NMOG+NOx. The equivalent Tier 2 Bin 5 fleet 

average in NMOG+ NOX terms is equal to 160 mg/mi (90 mg/mi NMOG + 70 mg/mi NOX).
Page 151 of 529

requirement (160 mg/mi total of NMOG and NOX). We expect that manufacturers 

will be able to achieve a fleetwide average below the Tier 2 Bin 5 level by several 

means, such as certifying LEV III vehicles either under Tier 2 or as Early Tier 3 

vehicles under Tier 3 (discussed in the next section) to bin levels lower than Tier 2 

Bin 5. Our analysis, presented in Section IV.A.5 above and Chapter 1 of the RIA, 

shows that manufacturers could certify many vehicles currently certified to Tier 2 

Bin 5 to a lower bin -- e.g., to Tier 2 Bin 3 or Bin 4 – by simply accepting a 

relatively small reduction in compliance margins. Many manufacturers certify Tier 

2 vehicles to Tier 2 Bin 5 but also certify the same vehicle to a cleaner emission 

standard under the LEV II program (e.g. ULEV) with only a compliance margin 

difference. 

We believe that the early credit provision will help us realize both our first 

and second goals presented above. For example, a manufacturer certifying their 

federal fleet to Tier 2 Bin 4 will earn 50 mg/mi of NMOG+ NOX credits per vehicle 

(i.e., 160 mg/mi minus 110 mg/mi), which we believe will encourage manufacturers 

to certify a cleaner federal fleet and provide a reasonable opportunity for credit 

generation to facilitate the “step down” in stringency. 

At the same time, if we allowed manufacturers to generate excessive early 

credits, manufacturers might thereby delay their compliance with the Tier 3 

program, and thus the harmonization with LEV III, for several years. This would

be in direct conflict with our third goal of creating a program of equal stringency to 

the California program as early as possible. In order to address this concern, we 

proposed and are finalizing a provision limiting the application of the early Tier 3

credits to the following conditions:

 Early Tier 3 credits generated as described above could be used without 

limitation in MY 2017 on the portion of the fleet entering the Tier 3 

program in that MY.

 Credits used for compliance in MY 2018 and beyond will be capped at 

an amount equal to the lesser of the manufacturer’s federal credits as 

calculated above or the manufacturer’s LEV III credits scaled up by the 

ratio of 50-state sales to California and LEV III required states sales. 

This limitation accounts for the fact that some LEV III credits may have 

begun to expire and will no longer be eligible as a basis for Tier 3 early 

credits.

By capping the available federal Tier 3 early credits, we believe that the two 

programs, LEV III and Tier 3 will be at parity in terms of relative stringency

starting in MY 2018. In addition, because the number of Tier 3 early credits that 

can be used is based on the number of LEV III credits that the manufacturer has

generated, there may be additional motivation for manufacturers to over-perform in 

California during the initial model years, accelerating emission reduction benefits.
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Finally, we are adopting, as proposed, a limitation on the life of Tier 3 early 

credits to 5 years, with no discounting, consistent with the California LEV III 

program.

b. Early Tier 3 Compliance

We are finalizing, as proposed, the requirement that manufacturers begin the 

Tier 3 program in MY 2017 for vehicles up to 6,000 lbs GVWR and MY 2018 for 

vehicles above 6,000 lbs GVWR under the primary phase-in. The only proposed 

compliance approach available prior to MY 2017 was for manufacturers to continue 

to certify vehicles to the existing Tier 2 standards with the opportunity to earn early 

credits (see previous section) that could be used in MY 2017 and later.

Several auto industry commenters suggested additional provisions that could 

facilitate earlier harmonization between Tier 3 and LEV III and streamlining of 

development and certification of vehicle models. Specifically, these commenters 

requested the ability to have vehicles certified to the Tier 3 standards in MYs 2015 

and 2016. They commented that this would allow them to develop, certify and sell a 

vehicle model for all 50 states, reducing the complexity of potentially different 

federal and California requirements in MYs 2015 and 2016. Additionally, 

commenters noted that the Tier 3 program provides more flexibility in the 

certification bin structure compared with the existing Tier 2, providing them 

additional opportunities to generate early credits.

To address this concern, we are finalizing a provision to allow 

manufacturers to certify to Tier 3 standards starting in MY 2015 as “Early Tier 3” 

vehicles. Manufacturers will have the option to certify their vehicle models to meet 

the Tier 3 emission requirements in MY 2015 and 2016 for all LDVs, LDTs, and 

MDPVs, which would have been required to begin in MY 2017 under the primary

program. As an example, a manufacturer choosing to certify a vehicle as Early Tier 

3 can bring the same vehicle models certified to LEV III standards324 in MY 2015 

or 2016 into the Early Tier 3 program by meeting all the same requirements under 

the primary Tier 3 schedule. There would not be a Tier 3 fleet average requirement 

for FTP or SFTP in MY 2015 or 2016 (and 2017 for vehicles over 6,000 lbs GVWR 

and up to 8,500 and MDPVs) if all the same vehicle models certified to LEV III are 

also certified as the Early Tier 3 vehicles meeting the same LEV III emission 

standards and also the Tier 3 additional requirements (high altitude, and cold CO 

and hydrocarbons). These Early Tier 3 vehicles would replace any Tier 2 offering 

of the vehicle model consistent with the LEV III offering replacing the LEV II 

models. If a manufacturers chooses to certify only a portion of their LEV III 

vehicle models as Early Tier 3 vehicles in a given MY, they will be required to 

 

324 Including LEV III SFTP requirements
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meet the LEV III fleet average requirements in that MY for those models certified 

as Early Tier 3 vehicles. All vehicles models not certified as Early Tier 3 vehicles 

must meet all Tier 2 requirements. 

c. Useful Life

The “useful life” of a vehicle is the period of time, in terms of years and 

miles, during which a manufacturer is responsible for the vehicle’s emissions 

performance. For the Tier 3 program, we are finalizing several changes to the 

existing useful life provisions that are appropriate to the new Tier 3 standards 

described above. 

The auto manufacturing industry has uniformly expressed the desire to 

produce and sell a single national vehicle fleet, including a general ability and 

willingness of the industry to certify their vehicles to a 150,000 mile, 15 year full 

useful life, as required by the LEV III program. However, the CAA, written at a 

time when vehicles did not last as long as they do today, precludes EPA from 

requiring a useful life value longer than 120,000 miles (and 10 or 11 years,

depending on vehicle category and weight) for lighter light-duty vehicles (LDVs 

and LDTs up to 3,750 lbs loaded vehicle weight (LVW) and up to 6,000 lbs GVWR 

(i.e., LDT1s)). 

For heavier light-duty vehicles (i.e., LDT2s, 3s, 4s, as well as MDPVs, 

representing a large fraction of the light-duty fleet), this statutory restriction does 

not apply, and we are finalizing a 150,000 mile, 15 year useful life value, as 

proposed. For the lighter vehicles, we are continuing to apply the 120,000 mile 

(and 10 or 11 year, as applicable) useful life requirement from the Tier 2 program, 

also as proposed. For these lighter vehicles, manufacturers are allowed to choose to 

certify to either useful life value in complying with the fleet average.325 In order 

for the Tier 3 NMOG+NOX standards to represent the same level of stringency

regardless of which useful life value manufacturers choose, we proposed and are 

finalizing proportionally lower numerical values (85 percent of the NMOG+NOX

150,000 mile standards based on a data analysis in Chapter 1 of the RIA) for the 

declining fleet average FTP NMOG+NOX standards when a manufacturer chooses 

the 120,000 mile useful life. A manufacturer choosing the 120,000 mile useful life

for any vehicle must maintain separate120,000 mile and 150,000 mile useful life

fleet averages for purposes of FTP NMOG+NOX fleet average compliance. Credits 

generated towards the required fleet averages are not transferable between the two 

useful life fleet averages. 

 

325 CARB has stated that they do not expect to accept vehicles certified under the federal Tier 3 

program to a 120,000 mile useful life value for California certification, and thus for meeting 

California’s fleet average NMOG+NOX standards.
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We proposed that a manufacturer that certifies any vehicle model under the 

120,000 mile provision be required to certify all their LDVs and LDT1s to the 

120,000 mile useful life and associated numerically lower FTP NMOG+NOX fleet 

average standard. Comments from the auto industry expressed a concern that this 

approach would be inflexible to manufacturers’ needs and unnecessarily 

burdensome. We have considered these comments, and we believe that the 

emission benefits of Tier 3 program will not be adversely affected if manufacturers 

are allowed to certify these lighter vehicles to the 120,000 mile useful life standards 

on a test group basis, and therefore we are finalizing this approach. Standards for 

all other pollutants326 and all other test cycles such as SFTP remain the same 

regardless of whether manufacturers choose the 120,000 mile or the 150,000 mile 

useful life periods. 

For emission standards other than PM standards (e.g., NMOG+NOX

standards), as proposed, manufacturers will be required to certify all vehicles to the 

150,000 mile useful life beginning with the first model year that a vehicle model is 

certified to the FTP NMOG+NOX Bin 70 or lower (other than vehicles not yet 

required to meet a 150,000 mile useful life during the program phase in, and 

vehicles for which a manufacturer has the option and chooses to apply the 120,000 

mile useful life value). This useful life requirement will apply as early as MY 2017. 

Beginning in MY 2020, all vehicles will need to certify to the 150,000 mile useful 

life for all emissions, regardless of NMOG+NOX certification bin, unless they are 

eligible for, and the manufacturer has chosen the 120,000 mile useful life and 

associated standards. (Note that the timing of the requirement to certify on the new 

test fuel follows the same approach as for the useful life requirement for emission 

standards other than PM standards (i.e., based on the first year a model is certified 

to FTP NMOG+NOX Bin 70 or below) as described in the next section.) For FTP 

and SFTP PM useful life requirements, manufacturers will be required to certify to 

150,000 mile useful life for PM all vehicles that are included in the manufacturer’s 

phase-in percentage meeting the new PM standards (other than eligible vehicles for 

which a manufacturer chooses to apply the 120,000 miles useful life value).

d. Test Fuels for Exhaust Criteria Emissions Standards

We recognize that test fuels are an important element of a national program. 

Vehicle manufacturers have emphasized in their comments the desire to reduce 

their test burdens by producing one vehicle that is tested on a single test procedure 

and on a single test fuel and that meets both California and federal requirements. 

Although we have been able to reasonably align the Tier 3 program with the LEV 

III program in most key respects, we recognize that the Tier 3 and LEV III test fuels 

are different, and that there may still exist some differences in emissions 

 

326 PM, CO, and HCHO.
Page 155 of 529

performance between vehicles tested on the two fuels. The largest difference 

between the two fuels is the Reid Vapor Pressure (RVP), and other differences in 

distillation properties and aromatic levels also exist (largely related to differences in 

actual in-use fuel nationally and in California). We are finalizing as proposed the 

requirement that manufacturers certify vehicles on the new Tier 3 E10 test fuels327

beginning with the first model year that a vehicle model is certified to the FTP 

NMOG+NOX Bin 70 or lower.

328 This requirement may apply as early as MY 2017

for vehicles up to 6000 lbs GVWR and MY 2018 for vehicles greater than 6000 lbs 

GVWR.329 This requirement also applies to vehicles certified at Bin 70 and lower 

that are brought into the Tier 3 program under the Early Tier 3 option described in 

IV.A.7.b above, with the exception of the specific provision allowing the use of 

LEV III fuels discussed below. Beginning in MY 2020, all gasoline-fueled models 

will need to certify on the Tier 3 test fuels for all exhaust emission requirements, 

regardless of their certification bin.330 As discussed in Section IV.A.7.c above, 

manufacturers must also meet the 150,000 mile useful life requirements for 

NMOG+NOX standards for these same vehicles as they are certified to Bin 70 and 

lower. 

During the transition period from Tier 2 fuel to the new Tier 3 and LEV III 

E10 fuels, manufacturers have indicated that they face a substantial workload 

challenge of developing and certifying each vehicle model to the two new fuels 

simultaneously. We recognize this transitional challenge and are including an 

additional option. We are finalizing as proposed an option that vehicles certified in 

MYs 2015 through 2019 to California LEV III standards using California LEV III 

E10 certification test fuels and test procedures can be used for certifying to EPA 

Tier 2 or Tier 3 exhaust emission standards, including PM. A manufacturer may

submit LEV III test data on vehicles tested using the new LEV III E10 fuels for Tier 

2 or Tier 3 certifications. Consistent with existing Tier 2 policy, EPA may test 

vehicles certified to Tier 2 standards using LEV III test results on Tier 2 fuel for 

confirmatory or in-use exhaust testing. For vehicles certified in MY 2017 through 

2019 to Tier 3 standards using LEV III E10 fuels, EPA will only use LEV III E10 

fuels for confirmatory and in-use testing (except for high altitude or cold CO and 

hydrocarbons testing, as described below). Vehicles certified to the provisions of 

Early Tier 3 (Section IV.A.7.b above) will be treated the same as Tier 3 vehicles 

certified in MY 2017. For example, for MY 2015 and 2016, EPA will consider 

 

327 This includes fuels used for cold temperature and high altitude testing and durability 

requirements. See Section IV.F below. 

328 The lower Bins are Bin 0, Bin 20, Bin 30 and Bin 50.

329 Vehicles above 6000 lb GVWR choosing the alternative phase-in schedules described in Section 

IV.A.2.c above generally would begin using the Tier 3 test fuels for MY2019. 

330 Diesel fueled and alternative fueled vehicles will continue to test on the fuels used under the Tier 

2 program except for E85 fueled vehicles, for which we are finalizing new test fuel specifications 

(see Section IV.F below). 
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Early Tier 3 vehicles to be part of the Tier 3 program for purposes of fuel-related 

testing obligations. We will not accept test results using LEV II fuels for Tier 3 

vehicle certification, including Early Tier 3 certifications, with the exception of the 

PZEV exhaust carry-over provision described below. 

California does not have fuel specifications for high altitude testing or cold 

CO and hydrocarbon testing. For this reason, we are finalizing that for vehicles that 

manufacturers choose to certify using LEV III fuel and test procedures, 

manufacturers must use program-specific federal test fuels to comply with these 

federal-only requirements (i.e. Tier 2 vehicles will use Tier 2 fuel and Tier 3 

vehicles will use Tier 3 fuel). Similarly, high altitude and cold CO and 

hydrocarbon confirmatory and in-use testing for these vehicles will be performed on 

the federal fuel that the manufacturer is required to use at certification as specified 

above regardless of whether LEV III or federal fuel is used for other testing. 

We proposed the requirement that after MY 2019, all Tier 3 certification, 

confirmatory and in-use emission testing be required to use only the proposed Tier 

3 E15 test fuel because it was believed to be a worse case fuel for emissions. 

Because we are finalizing Tier 3 E10 test fuels which are very similar as explained 

above to LEV III E10 test fuels, and not considered a worse case fuel, we are not 

finalizing the requirement for all testing to be performed on Tier 3 E10 test fuel. 

Instead, for certifications after MY 2019, EPA will continue to allow LEV III test 

results to be submitted for certification to Tier 3 standards, consistent with protocol 

under the Tier 2 program. However, if a manufacturer chooses to submit 

certification results for compliance with Tier 3 standards using the LEV III test fuel, 

then for confirmatory and in-use testing we will hold vehicles to the Tier 3 

standards while using the Tier 3 fuel in addition to the LEV III test fuel; we will not 

allow new or carry-over certifications using LEV II or Tier 2 certification test fuels 

after MY 2019. CARB has indicated that they will accept Tier 3 test data (on 

federal certification test fuels) to obtain a California certificate as early as MY 

2015. In this manner manufacturers should be able to avoid compliance testing on 

more than one fuel, since vehicles certified to Interim or Final Tier 3 status using 

federal certification test fuels could also obtain LEV III certification.

Auto industry commenters noted that the LEV III program provides an 

allowance for manufacturers to carry over PZEV-certified vehicle exhaust data331

from the LEV II program into LEV III compliance in MY 2015 through MY 2019. 

Thus, CARB allows these PZEV vehicles to use emission testing results using LEV

II fuel (i.e. California Phase II test fuel) to meet the LEV III obligations. The 

commenters suggested that EPA allow manufacturers to carry over such PZEV 

 

331 California’s PZEV exhaust standards are the same as their SULEV standards and the Tier 3 Bin 

30, and are certified to a 150,000 mile useful life. 
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150,000 mile useful life exhaust emission data to meet the Tier 3 standards. We 

agree that this approach is appropriate during the transition, and we are finalizing 

this provision for MY 2015 through MY 2019, including allowing Early Tier 3 

compliance at the Bin 30 level as a combined NMOG + NOX standard. EPA will 

hold vehicles certified using this provision to the Tier 3 emission requirements 

when they are tested on the LEV II fuel for confirmatory and in-use. Compliance 

testing of these vehicles for all other Tier 3 obligations (i.e., high-altitude testing 

and Cold CO and hydrocarbons testing) must be performed using Tier 3 fuel, and 

these vehicles will be required to meet the Tier 3 standards for Bin 30. 

e. High Altitude Requirements

FTP emission standards are historically designed to be applicable at all 

altitudes. Under Tier 2, the same FTP emission bin standards applied to vehicles 

tested at both low and high-altitude. However, fundamental physical challenges 

exist at high altitude resulting in typically higher emissions during cold starts 

compared with starts at lower altitudes (i.e., sea level), and these challenges become 

more pronounced as emission standards become more stringent. This expected 

increase in emissions is primarily due to the lower air density at higher altitudes. 

Due to the lower air density, the needed volume of the hot combustion exhaust 

required to quickly heat the catalyst in the first minute after a cold start is reduced. 

As a result, catalyst light-off is delayed and cold start emissions can increase. 

Vehicles under the Tier 2 program typically have had sufficient compliance margins 

to absorb this increase in emissions during testing under high-altitude conditions. 

However, given the extremely low standards we are finalizing in Tier 3, 

manufacturers will have less compliance margin with which to address the issue. 

Under the Tier 3 program, we expect that the emission control technologies 

selected for low altitude performance will also provide very significant emission 

control at high altitude.332 However, as explained above, unique emission 

challenges exist with operation at higher altitude, often requiring manufacturers to 

design their emission controls specifically for higher altitude.

We do not believe that the impact of the fairly small fraction of overall U.S. 

driving that occurs in high altitude locations warrants a requirement for additional 

technologies to be applied specifically for high-altitude conditions. To avoid 

requiring manufacturers to use special high-altitude emission control technologies, 

we are allowing manufacturers limited relief for certification testing at high altitude, 

as proposed. Specifically, for sea-level certifications to Tier 3 Bins 20, 30, and 50, 

a manufacturer could comply with the next less-stringent bin for testing at high 

 

332 High-altitude conditions means a test altitude of 1,620 meters (5,315 feet). Low altitude 

conditions means a test altitude less than 549 meters (1,800 feet).
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altitude. For example, a manufacturer can certify to Bin 50 for testing at high 

altitude versus Bin 30 at sea level). For vehicles certified at sea level to Bins 70 

and 125, manufacturers can comply with standards 35 mg/mi higher (e.g., 105 

mg/mi and 160 mg/mi, respectively. We are providing no high altitude relief for 

vehicles certified to Bin 160. This high altitude relief provision applies to all Final 

Tier 3 vehicles for the duration of the Tier 3 program. 

For intermediate altitudes that fall between the specified low and high 

altitude test conditions, the emission performance should continue to be 

representative of the controls implemented to meet standards at the required altitude 

test conditions, consistent with Tier 2 protocol. Any deviation in the use of these 

controls at the intermediate altitudes may be considered an AECD that must be 

reported by the manufacturer and justified as not being a defeat device333.

Table IV-9 presents the Tier 3 high altitude standards.

Table IV-9 Tier 3 High Altitude Standards

Bin Sea Level FTP Standard

(mg/mi NMOG+NOX)

Altitude FTP Standard

(mg/mi NMOG+NOX)

Bin 160 160 160

Bin 125 125 160

Bin 70 70 105

Bin 50 50 70

Bin 30 30 50

Bin 20 20 30

f. Highway Test Standards

Sustained high-speed operation can result in NOX emissions that may not be 

represented on either the FTP or SFTP cycles. Although we are not aware of any

serious issues with this mode of operation with current Tier 2 vehicles, we are 

interested in preventing increases in these NOX emissions as manufacturers develop 

new or improved engine and emission control technologies. 

For this reason, we are finalizing, as proposed, a provision that the Tier 3 

FTP NMOG + NOX standards above also apply on the Highway Fuel Economy Test 

 

333 §86.1809-12 Prohibition of defeat devices
Page 159 of 529

(HFET), which is performed as a part of GHG and Fuel Economy compliance 

testing. Thus, the Tier 3 FTP NMOG+NOX standard for the bin at which a 

manufacturer has chosen to certify a vehicle will also apply on the HFET test. For 

example, if a manufacturer certifies a vehicle to Bin 70, the vehicle’s NMOG+NOX

performance over the HFET could not exceed 70 mg/mi. Manufacturers will

simply need to ensure that the same emission control strategies implemented for the 

FTP and SFTP cycles are also effective during the highway test cycle. We believe 

that this requirement will not require manufacturers to take any unique 

technological action, will not add technology costs, and will not add significantly to 

the certification burden. 

g. Interim 4,000 Mile SFTP Standards

During the period of the declining NMOG+ NOX standards, we are 

finalizing the proposed requirement that interim Tier 3 vehicles meet 4,000 mile 

SFTP standards, consistent with the existing Tier 2 and LEV II program 

requirements. The 4,000 mile standards apply to each vehicle model individually 

and to each component of the SFTP composite cycle. This approach is designed to 

prevent excessive emission levels from individual vehicle models being masked by

the averaging of the manufacturer’s fleet emissions. Similarly, this approach also 

prevents poor performance on a single cycle of the SFTP. We believe it is 

appropriate to require any individual Interim Tier 3 vehicle to at a minimum meet 

the existing requirements under the Tier 2 and LEV II programs. Table IV-10

below presents the 4,000 mile SFTP standards for interim Tier 3 vehicles.

Table IV-10 4,000 Mile SFTP Exhaust Standards for Interim Tier 3 Vehicles 

(grams/mile)

Vehicle Category US06

NMOG+NOX

US06

CO

SC03

NMOG+NOX

SC03

CO

LDV/LDT1 0.14 8.0 0.20 2.7

LDT2 0.25 10.5 0.27 3.5

LDT3 0.4 10.5 0.31 3.5

LDT4 0.6 11.8 0.44 4.0

We believe that vehicles considered to be Final Tier 3 vehicles (i.e., they

meet the Tier 3 PM requirements, specifically the stringent SFTP PM standards) 

will have sufficiently robust designs that the 4,000 mile SFTP standards will no 

longer be necessary and so will not apply to those vehicles. Additionally, once the 

program reaches the fully phased-in fleet average composite standard of 50 mg/mi

in 2025, high SFTP emissions even on a limited portion of a manufacturer’s fleet 
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should be effectively mitigated, and the 4,000 mile SFTP standards will no longer 

apply. 

h. Phase-in Schedule

As proposed, the major provisions of the Tier 3 program phase in based on 

model year and on the emission levels to which manufacturers certify their vehicles. 

As described in Section IV.A.3, under the Tier 3 program, manufacturers are

required to certify each vehicle model to an FTP bin, which is then used to calculate

the NMOG+NOX fleet average of all of its Tier 3 vehicles. Manufacturers must

also determine the SFTP levels of each model and calculate the NMOG+NOX fleet 

average for the SFTP requirements as described in Section IV.A.4. These separate 

FTP and SFTP fleet average calculations satisfy one aspect of certification under 

the Tier 3 program, specifically the standards associated with each model year.

As described in Sections IV.A.7.c and IV.A.7.d above, the longer (150,000 

mile) useful life value, as applicable, and the new Tier 3 test fuel for exhaust testing 

will be implemented as manufacturers certify vehicles to more stringent 

NMOG+NOX standards, with the threshold to implement both of these provisions 

being Bin 70. Beginning in MY 2017, any vehicle certified to Bin 70 or lower will

be required to be certified on Tier 3 test fuel. In addition, any vehicle certified to 

Bin 70 or lower that is required to meet the longer 150,000 mile useful life will be 

required to do so at that point. Independent of the Tier 3 test fuel phase in schedule, 

the 150,000 mile useful life for PM standards will be required when the vehicle is 

certified to the new Tier 3 PM standards as described below in the PM phase-in 

schedules. Beginning in MY 2020, all gasoline-fueled vehicles will be required to 

be certified for exhaust emissions on the Tier 3 test fuel, regardless of their 

certification bin or applicable useful life.

Manufacturers must also comply with more stringent PM standards on a 

percent phase-in schedule. Compliance with the PM standards, which is consistent 

with the CARB LEV III program, is independent of the NMOG+NOX fleet average 

requirements described above. The PM emission standards for FTP and SFTP 

described in Section IV.A.3 and 4 respectively will be implemented as a percent 

phase-in requirement as described below under a primary phase-in schedule or 

under an optional phase-in schedule.

Vehicle models that a manufacturer certifies to a Tier 3 NMOG+NOX bin, 

that meet the requirements of the PM phase-in schedule, and that comply with the 

other Tier 3 requirements (i.e., 150,000 mile useful life and Tier 3 test fuel, as 

applicable) will be considered “Final Tier 3” compliant vehicles. All other vehicles 

certified to Tier 3 bins but not yet meeting the PM and other Tier 3 requirements 

will be considered “Interim Tier 3” compliant vehicles. At the completion of the 

percent phase-in period for PM (2021 for the primary PM phase-in schedule and 

2022 for the optional PM phase-in schedule, as described below), 100 percent of 
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vehicles will need to meet all of the Tier 3 requirements and will be considered 

Final Tier 3 vehicles. 

As proposed, for the PM requirements, each model year manufacturers must

meet either the primary PM percent phase-in or the optional PM phase-in as 

described in the following subsections. The primary percent PM phase-in schedule 

is composed of fixed annual minimum phase-in percentages that we expect most 

manufacturers to choose in order to comply with the Tier 3 requirements. The 

optional PM phase-in schedule provides additional flexibility for manufacturers 

with too few product offerings to allow for a sufficiently gradual transition into the 

Final Tier 3 requirements, as described below. In either case, Interim Tier 3 

vehicles not yet meeting the Tier 3 PM standards must at a minimum meet the Tier 

2 PM full useful life FTP PM standard of 10 mg/mi and the SFTP PM weighted 

composite standard of 70 mg/mi. 

i. Primary PM Percent Phase-In Schedule

It is important to note that the percent phase-in of the new Tier 3 PM 

standards and the declining fleet average NMOG+NOX standards that we are 

finalizing are separate and independent elements of the Tier 3 program. “Phase-in” 

in the context of Tier 3 PM standards means the fraction of a manufacturer’s fleet 

that is required to meet the new Tier 3 PM standards in a given model year. We 

expect that manufacturer fleets may consist of a mix of vehicle models certified to 

Tier 2, LEV II, LEV III and Tier 3 standards throughout the percent phase-in 

period. 

As discussed above, vehicles originally certified to Tier 2, LEV II, and LEV 

III may be carried over into the Tier 3 program as Interim Tier 3 vehicles. A 

vehicle will be considered a Final Tier 3 vehicle when it is certified to one of the 

Tier 3 bins, meets the new Tier 3 PM standards for FTP (3mg/mi) and US06 (10 or 

6 mg/mi), certifies to the 150,000 useful life value (as applicable), and certifies on 

the new Tier 3 test fuel. Table IV-11 below presents the PM phase-in schedule for 

Final Tier 3 vehicles.

Table IV-11 PM Phase-in Schedule for Final Tier 3 Vehicles

Model Year 2017 2018 2019 2020 2021 2022 

and 

later

Manufacturer’s

Fleet (%)

20 a20 40 70 100 100
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Vehicle Types

≤ 6,000 lbs 

GVWR

All vehicles ≤ 8,500 lbs GVWR and MDPVs

a Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs

GVWR, or alternatively with 10 percent of their total LDV, LDT, and MDPV fleet Optional PM 

Phase-in

The PM percent-of-sales phase-in schedule described above will allow 

manufacturers with multiple vehicle models to plan the phase-in of those models 

based on anticipated volumes of each vehicle model. However, manufacturers 

certifying only a few vehicle models might not benefit from this schedule. This is 

because, in order to satisfy the phase-in schedule percentages, they may have to 

over-comply with the required percentages earlier than will a manufacturer with 

many vehicle models available for the phase-in. 

For instance, a manufacturer with only two models that each equally 

account for 50 percent of their sales will be required to introduce (at least) one of 

the models in MY 2017 to meet the PM phase-in requirement of 20 percent in the 

first year. Because it represents 50 percent of the manufacturer’s sales, this model 

will then also meet the requirements for MY 2018 (20 percent) and MY 2019 (40 

percent). To meet the MY 2020 requirement of 70 percent of sales, however, the 

manufacturer will need to introduce the second Tier 3 vehicle that year. Thus the 

manufacturer will have introduced 100 percent of its Tier 3 models one year earlier 

than required of a manufacturer that is able to delay the final 30 percent of its fleet 

until MY 2021 (by distributing its models over the entire phase-in period).

To provide for more equivalent phasing in of the PM requirements among 

all manufacturers in the early years of the program, we are finalizing, as proposed,

an optional “indexed” PM phase-in schedule that can be used by a manufacturer to 

meet its PM percent phase-in requirements. A manufacturer that exceeds the phasein requirements in any given year will be allowed to, in effect, offset some of the 

phase-in requirements in a later model year. The optional phase-in schedule will be 

acceptable if it passes a mathematical test. The mathematical test is designed to 

provide manufacturers a benefit from certifying to the standards at higher volumes 

than they are obligated to under the normal phase-in schedule, while ensuring that 

significant numbers of vehicles are meeting the new Tier 3 requirements during 

each year of the optional phase-in schedule. In this approach, manufacturers weight 

the earlier years by multiplying their percent phase-in by the number of years prior 

to MY 2022 (i.e., the second year of the 100 percent phase-in requirement). 

The mathematical equation for applying the optional PM phase-in is as 

follows:
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(5 x APP2017) + (4 x APP2018) + (3 x APP2019) + (2 x APP2020) + (1 x 

APP2021) ≥540, where APP is the actual phase-in percentage for the referenced 

model year. 

The sum of the calculation must be greater than or equal to 540, which is the 

result when the optional phase-in equation is applied to the primary percent phasein schedule (i.e., 5 x 20% + 4 x 20% + 3 x 40% + 2 x 70% + 1 x 100% = 540).

Applying the optional PM phase-in equation to the hypothetical 

manufacturer in the example above, the manufacturer can postpone its model 

introductions by one year each, to MY 2018 and MY 2021. Its calculation is (5 x 

0% + 4 x 50% + 3 x 50% + 2 x 50% + 1 x 100% = 550, and thus the phase-in is

acceptable. 

i. In-use Standards 

i. NMOG + NOX

The Tier 3 emission standards will require a substantial migration of 

emission control technology historically used only on a small percent of the fleet 

and typically limited to smaller vehicles and engines. While we believe that these 

technologies can generally be used on any vehicle and are applicable to the entire 

fleet, manufacturers have less experience with the in-use performance of these 

technologies across the fleet. For example, technologies that accelerate catalyst 

warm-up such as catalyst location close to the engine exhaust ports and other 

advanced thermal management approaches will be new to certain vehicle types, 

particularly larger vehicles (i.e., LDT3/4s), which have historically not relied on 

these technologies to meet emission standards.

As proposed, to help manufacturers address the lack of in-use experience 

and associated challenges with the expanded introduction of these technologies,

particularly in the larger vehicles, we are finalizing temporarily-relaxed in-use 

NMOG+NOX standards that will apply to all vehicles certified to Bins 70 and 

cleaner as Interim or Final Tier 3 vehicles. The in-use standards will apply during 

the entire percent phase-in period (i.e., through MY 2021). The in-use standards are

40 percent less stringent than the certification standards, providing a significant but 

reasonable temporary cushion for the uncertainties associated with new 

technologies (or new applications of existing technologies) over the life of the 

vehicles.

 The in-use NMOG + NOX standards are shown in Table IV-12. 
Page 164 of 529

Table IV-12 FTP In-Use Standards for Light Duty Vehicles and MDPVs 

(mg/mi)

Bin NMOG+NOX

(mg/mi)

Bin 160 160

Bin 125 125

Bin 70 98

Bin 50 70

Bin 30 42

Bin 20 28

ii. PM

As with the NMOG+NOX standards, the introduction of new emission 

control technologies or new applications of existing technologies (e.g., GDI, 

turbocharging, downsized engines) will create significant uncertainties for 

manufacturers about in-use performance over the vehicle’s useful life. We are 

finalizing as proposed a temporary in-use FTP standard for PM of 6 mg/mi for all 

light duty vehicles certified to the Tier 3 full useful life 3 mg/mi standard. Since the 

Tier 3 FTP PM standard has a percent phase-in schedule spread over several years, 

starting in 2017 with full phase-in completed in 2022, we are finalizing the 

requirement that the in-use standard apply to all vehicles certified to the new PM 

standards during the entire percent phase-in period (i.e., through MY 2021).

We also proposed temporarily-relaxed in-use US06 PM standards. As 

described in Section IV.A.4.b above, we are finalizing an in-use US06 PM standard 

of 10 mg/mi for the intermediate years of the program (MYs 2019 through 2023) in 

response to industry concerns about emissions variability as the new standards 

become effective. 

j. FFVs

Because of the physical and chemical differences in how emissions are 

generated and controlled between vehicles operating on different blends of gasoline 

and ethanol, manufacturers of vehicles designed for high-percentage blends of 

ethanol (usually called Flexible Fuel Vehicles, or FFVs) may face unique 

compliance challenges under the Tier 3 program. Historically, under the Tier 2 

program, FFVs have only been required to meet all Tier 2 emission standards, FTP 

and SFTP, while operating on gasoline (E0); when operating on the alternative fuel 

(generally this means a blend that is nominally 85 percent ethanol, or E85), they

have only been required to meet the FTP emission standards. 
Page 165 of 529

However, E85 use may rise considerably in the future as ethanol use 

increases in response to the Renewable Fuels Standards (RFS). Thus, as the Tier 3 

program is implemented, it is increasingly important that FFVs maintain their 

emission performance when operating on E85 across different operating conditions.

We believe that at standard test conditions, requiring manufacturers to meet 

the Tier 3 standards on any blend of gasoline and ethanol will not be significantly

more challenging technologically than compliance on lower ethanol blends, 

including the E10 Tier 3 test fuel we are adopting. We are thus finalizing, as 

proposed, the requirement that in addition to complying with the Tier 3 

requirements when operating on Tier 3 test fuel, FFVs also comply with both the 

FTP and the SFTP emission standards when operating on E85. This includes the 

requirement to meet emission standards for both Tier 3 test fuel and E85 for the 

FTP, highway test, and SFTP emission standards at standard test temperatures (i.e., 

68 °F to 86 °F). Since FFVs can operate on any blend of gasoline and ethanol (up 

to a nominal 85 percent ethanol), the emission requirements apply to operation at all 

levels of the alternative fuel that can be achieved with commercially available fuels. 

However, for exhaust emission compliance demonstration purposes, we will test on 

Tier 3 test fuel and on fuel with the highest available ethanol content. 

k. Credit for Direct Ozone Reduction (DOR) Technology

Since the late 1990s, technologies have been commercialized with which 

vehicles can remove ozone from the air that flows over the vehicle’s coolant 

radiator. In such direct ozone reduction (DOR) technology, a catalytic coating on 

the radiator is designed to convert ambient ozone into gaseous oxygen, as a way of 

addressing the air quality concerns about ozone. Detailed technical analyses for the 

California LEV II and the federal Tier 2 programs showed that when properly

designed these systems can remove sufficient ozone from the air to be equivalent to 

a quantifiable reduction in tailpipe NMOG emissions. In the earlier programs, both 

California and EPA provided methodologies through which a manufacturer could 

demonstrate the capability and effectiveness of the ozone-reducing technology and 

be granted an NMOG credit. A small number of vehicle models with DOR 

applications received credit under the LEV II program; no manufacturer formally

applied for credits under the federal Tier 2 program.

Some manufacturers have expressed an interest in the continued availability 

of a DOR credit as a part of their potential LEV III and Tier 3 compliance 

strategies. EPA believes that when a DOR system is shown to be effective in 

reducing ozone, a credit toward Tier 3 compliance is warranted. We are finalizing a 

provision, as proposed, that manufacturers following the California methodology

for demonstrating effectiveness and calculating a appropriate credit for a DOR 
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system be granted a specific credit toward the NMOG portion of the NMOG+NOX

standard.334 As with the California program, such a credit may not exceed 5 mg/mi 

NMOG. 

l. Credit for Adopting a 150,000-Mile Emissions Warranty

Under the Tier 3 standards, manufacturers are expected to design their 

emission control systems to continue to operate effectively for a useful life of 

150,000 miles (120,000 miles for some smaller vehicles). However, manufacturers 

are only required to replace failed emission control components or systems on 

customers’ vehicles for a limited time period, specified in the Clean Air Act (80,000 

miles/8 years for key emission control components). EPA believes that voluntary

extension of this warranty obligation by manufacturers would provide additional 

emission reductions by helping ensure that controls continue to operate effectively

in actual operation through the full life of the vehicle. 

We are finalizing as proposed that a manufacturer providing its customers 

with a robust emission control system warranty of 15 years or 150,000 miles be 

eligible for a modest credit of 5 mg/mi NMOG+NOX.

335

 Because of the significant 

liability that manufacturers would be accepting, we do not expect that the use of this 

credit opportunity will be widespread. However, based on our modeling of the 

expected deterioration of the emissions of future Tier 3 vehicles absent 

repair/replacement of failed emission controls, we anticipate that the value to the 

environment of long emissions warranties in terms of reduced real-world emissions 

would significantly exceed the 5 mg/mi NMOG+NOX credit.336

We will use the same criteria for approving such a credit as does the parallel 

California program.337 Thus, in addition to committing to customers that failing 

emission controls will be repaired or replaced for 15 years/150,000 miles, 

manufacturers will also need to accept the liability that in the event that a specific 

emissions control device fails on greater than 4 percent of a vehicle model’s 

production, they will recall the entire production of that model for repair. 

m. Averaging, Banking, and Trading of Credits

We proposed and are finalizing an averaging, banking, and trading (ABT) 

program similar to those that have historically been a part of most EPA emission 

 

334 EPA is incorporating the CARB DOR methodology by reference. 

335 Manufacturers choosing to comply with the standards for a 120,000 mile useful life for their 

LDVs and LDT1s are not eligible for this extended warranty credit for those vehicles.

336 Beardsley, M, et al. (2013, February). Updates to MOVES for the Tier 3 NPRM. Memorandum 

to the docket.

337 EPA is incorporating the CARB extended emission warranty provisions by reference.
Page 167 of 529

control programs. For the Tier 3 final rule, the ABT program is consistent with the 

other Tier 3 program elements, the heavy duty exhaust emission standards and the 

evaporative emission standards programs, with the only exception being credit life 

during the longer phase in for the light duty program as described below. The ABT 

program is intended to provide an opportunity for manufacturers to deploy their 

Tier 3 vehicle models more efficiently, especially during the transition years, and to 

avoid excessive delays in the necessary technological improvements across the 

fleet. We have designed the Tier 3 ABT program to provide for credits to be 

generated by certifying vehicles that perform better than the fleet-average 

NMOG+NOX standards. These credits may be used within a company to offset 

vehicles that perform worse than the standards, they may be banked for later use, or 

they may be traded to other manufacturers. 

We are also finalizing limitations on the use of credits for the light-duty 

fleet. We proposed that Tier 3 credits expire after 5 model years following the 

model year they are generated and solicited comment on the Tier 3 credit life. In 

communications regarding the proposed rule, representatives of the auto industry

expressed to EPA that the value of the ABT program during the MY 2017-2025 

phase-in of the primary program would be improved if credits had a longer credit 

life.338 We determined that, with certain restrictions, Tier 3 credit life can be 

temporarily extended with no adverse impacts on the overall emission reductions of 

the program. Specifically, we are finalizing a credit life of 8 years for credits 

generated in MYs 2017-2022 for the FTP and SFTP NMOG+NOX fleet average 

standards for the primary program only. For the heavier light-duty vehicles, the 8-

year credit life begins for credits generated in MY 2018. Note that, as proposed, 

credits generated under the Early Tier 3 Credit provision (Section IV.A.7.a) are 

limited to 5-year life, and are not affected by the longer credit life. 

For credits generated in MYs 2023-2025, the credit life declines by one year 

of credit life annually, with credit life stabilizing at 5 years for credits generated in 

MYs 2025 and later. That is, credits generated in MY 2023 have a 7-year life, in 

MY 2024 a 6-year life, and in MY 2025 and later a 5-year life. However, while 

credits can be generated, banked, and used internally for the extended time periods, 

credits cannot be traded to other manufacturers after 5 years.

After considering the views expressed by manufacturers as well as the 

implementation schedules of this Tier 3 rule and the 2017 light-duty GHG rule, we 

believe that the temporary up-to-8-year credit life available to manufacturers during 

the phase-in period provides substantial flexibility to address manufacturer

uncertainties about future technology development and product planning during 

 

338 Passavant, G. (January2014), Meetings with Chrysler – Tier 3 NPRM Lead Time and ABT, 

Memorandum to Docket. 
Page 168 of 529

implementation of the Tier 3 program. We also believe this longer credit life 

provision will alleviate most if not all concerns expressed by manufacturers with 

respect to the challenges they may encounter by simultaneous implementation of 

the two programs.

As proposed, we are finalizing a provision for a manufacturer to create a 

credit deficit, at certification or at the end of the production year, if its fleet average 

emissions exceed the standard. A manufacturer would be required to use all of its 

banked credits, if any, before creating a credit deficit. A credit deficit would need 

to be resolved before the fourth model year after the deficit was created; that is, a 

manufacturer may not maintain a credit deficit more than 3 consecutive model 

years. 

n. Tier 3 Transitional Emissions Bins

During the development of the proposed rule and in their comments, 

manufacturers pointed out that they may continue to produce some vehicles as late 

as MY 2019 that could be certified to Tier 2 Bin 3 or Bin 4 standards. In order to 

provide manufacturers flexibility in meeting the fleet average standards and to 

further facilitate the transition, we will allow manufacturers to certify to the 

combined NMOG+NOX levels of these Tier 2 bins through MY 2019. We are 

finalizing two transitional Tier 3 bins, Bin 110 and Bin 85, that have FTP 

NMOG+NOX standards of 110 mg/mi and 85 mg/mi, respectively (i.e., the sum of 

the NMOG and NOX values from the Tier 2 bins). The associated FTP standards 

for CO, PM, and HCHO corresponding to these bins are identical to those for 

vehicles certified to the Tier 3 Bin 125. Tier 3 SFTP standards will apply to these 

vehicles, and these vehicles will be included in the Tier 3 PM percent phase-in 

calculations. 

o. Compliance Demonstration

In general, we are finalizing requirements that manufacturers demonstrate 

compliance with the Tier 3 light-duty vehicle emission standards in a very similar 

manner to existing Tier 2 vehicle compliance (see §86.1860 of the regulatory 

language). However, for Tier 3, manufacturers must calculate their compliance 

with the fleet average standards and percent phase-in standards based on annual 

nationwide sales, including sales in California and Clean Air Act Section 177 states. 

We believe that this approach represents another step toward achieving the goal of 

an effectively nationwide program as early as possible, which has been a basic 

principle in EPA’s development of this program and broadly supported by vehicle 

manufacturers. We also believe that basing compliance on nationwide sales may

reduce the need for manufacturers to project future sales and track past years’ sales 

in a disaggregated way. Because the Tier 3 provisions become increasingly 

consistent with LEV III provisions as the Tier 3 program phases in, we believe that 
Page 169 of 529

any disproportionate impacts of different mixes of vehicles in different states are 

unlikely to occur. 

This nationwide compliance calculation approach applies to vehicles as they

become subject to the Tier 3 provisions, either the declining fleet-average 

NMOG+NOX curves or the percent phase-in PM standards. Were any manufacturer 

to choose to use the alternative FTP and SFTP phase-ins, which are not a part of the 

LEV III program, the manufacturer would not include sales in California or in the 

Section 177 states in its compliance calculations. 

B. Tailpipe Emissions Standards for Heavy-Duty Vehicles 

1. Overview and Scope of Vehicles Regulated 

After considering the comments we received, we are adopting the Tier 3 

exhaust emissions standards that we proposed for chassis-certified heavy-duty

vehicles (HDVs) between 8501 and 14,000 lbs gross vehicle weight rating 

(GVWR). Vehicles in this GVWR range are often referred to as Class 2b (8501-

10,000 lbs) and Class 3 (10,001-14,000 lbs) vehicles, and are typically full-size 

pickup trucks and work vans certified as complete vehicles.

339

 Medium-duty

passenger vehicles (MDPVs), although in the Class 2b GVWR range, are subject to 

Tier 3 standards discussed in Section IV.A. To a large extent, we are also adopting 

the Tier 3 certification testing and compliance provisions that we proposed for 

HDVs. There are, however, a number of improvements we are making in response 

to comments, as discussed in detail below.

The Tier 3 program for HDVs will bring substantial reductions in harmful 

emissions from this large fleet of work trucks and vans, a fleet that is used

extensively on every part of the nation’s highway, rural, and urban roadway system. 

The fully-phased in Tier 3 standards levels for non-methane organic gas (NMOG) 

plus oxides of nitrogen (NOX), and for particulate matter (PM), are on the order of 

60 percent lower than the current standards levels.

We proposed to require that diesel-fueled Class 2b and 3 complete vehicles, 

like their gasoline-fueled counterparts, be certified to the Tier 3 standards on the 

chassis test; we also proposed to include these vehicles in the Tier 3 HDV 

 

339 40 CFR 86.1803-01 defines HDVs to also include motor vehicles at or 

below 8,500 lbs GVWR that have a vehicle curb weight of more than 6,000 lbs or a 

basic vehicle frontal area in excess of 45 square feet, and these vehicles will also be 

subject to the Tier 3 standards and other provisions applicable to Class 2b vehicles 

discussed in this section.
Page 170 of 529

averaging, banking, and trading (ABT) program. Currently only gasoline-fueled 

Class 2b/3 complete HDVs are required to chassis certify.

The International Council for Clean Transportation (ICCT) provided 

comments in support of this requirement, arguing that it is needed to stop 

manufacturers from making trucks marginally above 8500 lbs GVWR to avoid 

light-duty emission standards. The Truck and Engine Manufacturers Association 

(EMA) opposed mandatory chassis certification for any class of engines or vehicles 

over 8500 lbs GVWR, arguing that the existing flexibility is needed to minimize 

unnecessary costs and certification burdens. EMA commented that, at a minimum, 

EPA should maintain optional certification of diesel engines used in complete Class 

3 vehicles. In their joint comments, the Alliance of Automobile Manufacturers and 

the Association of Global Automakers also requested that EPA retain the option for 

complete Class 3 diesel vehicles and engines, arguing that otherwise manufacturers 

may be required to dual certify vehicle models that include variants both under and 

over 14,000 lbs.

We are sensitive to this issue but remain concerned that the fleet average 

standard program we are finalizing would not work well if a major fleet component, 

such as complete Class 3 diesel trucks, can be left in or taken out of the fleet 

calculation based on what each manufacturer considers to be most advantageous. 

We believe the resulting competitive issues and uncertainties would be problematic, 

given the wide variance in gasoline/diesel HDV sales among the manufacturers, our 

provision for averaging across each manufacturers’ entire Class 2b/3 fleet, and the 

overwhelming preponderance of diesels in the Class 3 market. It would also create 

uncertainties in the Tier 3 environmental benefits, given the pronounced difference 

between these Tier 3 standards and the heavy-duty diesel engine standards we set 

13 years ago, which we expect to remain in effect for the foreseeable future. 

As a result, we are finalizing these provisions as proposed, except that we 

are providing that manufacturers, instead of certifying complete diesel Class 3 

HDVs, may install diesel engines that have been engine-certified for any model 

year that the engine family has less than half of its sales being installed in such nonchassis-certified complete Class 3 vehicles. For example, if a company has a 

certified diesel engine family with 10,001 sales in MY 2020, up to 5,000 of those 

engines may be installed in complete Class 3 HDVs that are not chassis-certified for 

exhaust emissions. This provision is intended to help address manufacturers’ 

concern about dual certification, while at the same time ensuring a coherent 

fleetwide standards regimen in this vehicle class. It also better harmonizes with 

California’s low-emission vehicle (LEV) III program which does not mandate 

chassis certification for diesel Class 3 vehicles. By only allowing engine-certified 

vehicles in the case of engines that are primarily produced for other purposes, we 

believe this approach adequately guards against potential abuse. In the case of 

complete diesel Class 3 HDVs produced by a company other than the engine 

certifier, the responsibility for ensuring the sales limit is not exceeded remains with 
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the vehicle manufacturer, who will need to coordinate with the engine supplier to 

ensure compliance.

Manufacturers of incomplete HDVs that are sold to secondary

manufacturers for subsequent completion (less than 10 percent of the Class 2b and 3 

U.S. market) are also allowed under existing EPA regulations to certify via either 

the chassis or engine test, and those who choose to chassis-certify in the future will

be subject to Tier 3 requirements. We asked for comment on mandating chassis 

certification of incomplete Class 2b and 3 vehicles, noting that California’s LEV III 

program includes such a requirement for Class 2b. Commenters expressed 

opposition to this extension of mandatory chassis certification, despite their general 

support for harmonization with LEV III; as a result, we are not mandating chassis 

certification for any incomplete HDVs.

The key elements of the Tier 3 program for HDVs parallel those for 

passenger cars and light-duty trucks (LDTs), with adjustments in standards levels, 

emissions test requirements, and implementation schedules, appropriate to this 

sector. These key elements include:

 a combined NMOG+NOX declining fleet average standard beginning in 2018 

and reaching the final, fully phased-in level in 2022, 

 creation of a bin structure for standards, including standards for carbon 

monoxide (CO) and formaldehyde,

 PM standards phasing in separately on a percent-of-sales basis, 

 changes to the test fuel for gasoline- and ethanol-fueled vehicles, 

 extension of the regulatory useful life to 150,000 miles,

 a new requirement to meet standards over the supplemental federal test 

procedure (SFTP) that addresses real-world driving modes not well-represented 

by the federal test procedure (FTP) cycle alone, and

 special flexibility provisions for small businesses and small volume 

manufacturers described in Section IV.G.

As in the light-duty Tier 3 program, we have put a strong emphasis on 

coordinating HDV Tier 3 program elements with California’s LEV III program for 

Class 2b and 3 vehicles, referred to in LEV III as medium-duty vehicles (MDVs). 

The goal is to create a coordinated “national program” in which California would 

accept compliance with Tier 3 standards as sufficient to also satisfy LEV III 

requirements, thus allowing manufacturers to comply nationwide by marketing a 

single vehicle fleet. As part of this effort, we proposed that manufacturers of Tier 3 
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HDVs calculate compliance with the fleet average standards and percent phase-in 

standards based on annual nationwide sales, including sales in California and in 

states implementing California standards under Clean Air Act section 177. 

Commenters expressed emphatic support for this approach and we are finalizing it 

as a key element of the Tier 3 program.

2. HDV Exhaust Emissions Standards

a. Bin Standards

Manufacturers will certify HDVs to Tier 3 requirements by having them 

meet the standards for NMOG+NOx, PM, CO and formaldehyde for one of the bins 

listed in Table IV-13. Manufacturers choose bins for their vehicles based on their 

product plans and corporate strategy for compliance with the fleet average standards 

discussed in Section IV.B.2.b, and once a vehicle’s bin is designated, those bin 

standards apply throughout its useful life. Because the fleet average standards 

become more stringent over time, the bin mix will gradually shift from higher to 

lower bins. 

As in the past, there are numerically higher standards levels for Class 3 

vehicles than for Class 2b vehicles, reflective of the added challenge in reducing 

per-mile emissions from large work trucks designed to carry and tow heavier loads. 

Also, the standards levels for both Class 2b and Class 3 HDVs are significantly

higher than those being adopted for light-duty trucks due to marked differences in 

vehicle size and capability, and to our requirement to test HDVs in a loaded 

condition (at the adjusted loaded vehicle weight (ALVW)). By conducting 

emissions testing with loaded vehicles, the heavy-duty program ensures that 

emissions controls are effective when these vehicles are performing one of their

core functions: hauling heavy loads. This is a key difference between the heavyduty and light-duty truck programs. The bin structure and standards levels are 

consistent with those in California’s LEV III program. We requested comment on 

the usefulness of creating additional bins between Bin 0 and the next lowest bin in 

each vehicle class, as a means of encouraging clean technologies and adding 

flexibility, but commenters saw no need for these.

Table IV-1 FTP Standards for HDVs

NMOG+NOX

(mg/mi)

PM

(mg/mi)

CO

(g/mi)

Formaldehyde

(mg/mi)

Class 2b (8501-10,000 lbs GVWR):

Bin 395 (interim) 395 8 6.4 6

Bin 340 (interim) 340 8 6.4 6

Bin 250 250 8 6.4 6

Bin 200 200 8 4.2 6

Bin 170 170 8 4.2 6
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Bin 150 150 8 3.2 6

Bin 0 0 0 0 0

Class 3 (10,001-14,000 lbs GVWR):

Bin 630 (interim) 630 10 7.3 6

Bin 570 (interim) 570 10 7.3 6

Bin 400 400 10 7.3 6

Bin 270 270 10 4.2 6

Bin 230 230 10 4.2 6

Bin 200 200 10 3.7 6

Bin 0 0 0 0 0

The NMOG+NOX standards levels for the highest bins in each class (Class 

2b Bin 395 and Class 3 Bin 630) are equal to the sum of the current non-methane 

hydrocarbon (NMHC) and NOX standards levels that took full effect in 2009, as 

well as to equivalent LEV standards in California’s LEV II program. These bins 

are intended as carryover bins. That is, we expect them to be populated with 

vehicles that are designed to meet the current standards, and that are being phased 

out as new lower-emitting vehicle designs phase in to satisfy the Tier 3 fleet 

average NMOG+NOX standard. We also consider the next highest bins (Class 2b 

Bin 340 and Class 3 Bin 570) to be carryover bins, because they likewise can be 

readily achieved by vehicles designed for today’s EPA and California LEV II 

emissions programs. As the 2018-2022 phase-in progresses, it will become 

increasingly difficult to produce vehicles in these bins and still meet the fleet 

average standard. Therefore vehicles in these bins (as well as some others not yet 

designed to meet Tier 3 PM standards described in Section IV.B.2.d) will be 

considered “interim Tier 3” vehicles, and the bins themselves will be considered 

“interim bins.”

To facilitate their use in this carryover function, the interim bins do not 

require manufacturers to meet Tier 3 exhaust emissions standards on the SFTP, over 

the longer useful life, or with the new gasoline test fuel discussed in Section IV.F, 

although testing on this fuel will be allowed. These requirements do apply in all 

other bins.

In the context of these relaxed requirements for the interim bins, we 

proposed two additional measures to help ensure these bins are focused on their 

function of helping manufacturers transition to the long-term Tier 3 emissions 

levels. First, we proposed that the interim bins would be available only in the 

phase-in years of the program; that is, through model year (MY) 2021, as is 

appropriate to their interim status. Second, vehicles in the interim bins would meet 

separate NMOG and NOX standards rather than combined NMOG+NOX standards. 

The goal was to ensure that a manufacturer does not redesign or recalibrate a 

vehicle model under combined NMOG+NOX Tier 3 standards for such purposes as 

reducing fuel consumption, through means that result in higher NOX or NMOG 
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emissions than exhibited by today’s vehicles, contrary to the intended carryover

function of the interim bins. Industry commenters objected to both the proposed 

sunsetting of the interim bins and the proposed separate NOx and NMOG standards, 

arguing that they overly restrict manufacturer flexibility and work against 

harmonization with LEV III. However, commenters did not address EPA’s concern 

regarding increased NOx emissions at the interim bin levels.

After considering the comments, we believe a modified approach to the 

interim bins can at least partly address the industry concerns regarding 

harmonization while still precluding backsliding on NOx levels. We are finalizing 

the interim bins with combined NMOG+NOx standards as requested by the 

commenters, but are adopting a restriction on deterioration-adjusted NOx levels in 

certification testing, to the levels allowed under the current standards in 40 CFR 

86.1816-08. These are 0.2 and 0.4 g/mi for Class 2b and Class 3, respectively. 

This restriction will not apply to vehicles in use, and does not impose a parallel 

NMOG restriction. Given our continuing concerns about NOx increases that would 

be allowed by the combined standards at the interim bin levels, we believe that this 

approach and the associated certification burden are reasonable, noting that 

manufacturers already must obtain NOx test results in certifying to an 

NMOG+NOx standard, and the differing NOx and NMOG deterioration 

mechanisms will likely dictate that they be considered separately in obtaining 

deteriorated NMOG+NOx levels for certification.

We believe that making the interim bins available indefinitely would run 

counter to their limited purpose as an aid to making the transition to Tier 3 

emissions levels. Making these bins permanent would, we believe, necessitate that 

they take on other key elements of the Tier 3 program such as longer useful life, 

SFTP compliance, and the use of Tier 3 test fuel. These requirements in turn would 

negate the usefulness of these bins in helping to carry over some pre-Tier 3 vehicle 

designs during the transition years in which the declining fleet average standard 

levels are high enough to accommodate their continued sale. By MY 2022, the 

fleetwide standard will be stringent enough to effectively eliminate the ability of 

manufacturers to use interim bins while meeting the declining fleet average 

standard levels. We are therefore adopting the sunsetting of the interim bins as 

proposed, making them available only through MY 2021.

b. Fleet Average NMOG+NOX Standards

As in the light-duty Tier 3 program, a key element of the program we are 

finalizing for HDVs is a fleet average NMOG+NOX standard that becomes more 

stringent in successive model years: in the case of HDVs, from 2018 to 2022. Each 

HDV sold by a manufacturer in each model year contributes to this fleet average 

based on the mg/mi NMOG+NOX level of the bin declared for it by the 

manufacturer. Manufacturers may also earn or use credits for fleet average 

NMOG+NOX levels below or above the standard in any model year, as described in 
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Section IV.B.4. As proposed, we are adopting the separate Class 2b and Class 3 

fleet average standards shown in Table IV-13, though a manufacturer can

effectively average the two fleet classes using credits (see Section IV.B.4). We 

believe this split-curve approach is superior to a single phase-in covering all HDVs 

because it recognizes the different Class 2b/Class 3 fleet mixes among 

manufacturers and the differing challenge in meeting mg/mi standards for Class 3 

vehicles compared to Class 2b vehicles, while still allowing for a corporate 

compliance strategy based on a combined HDV fleet through the use of credits.

We are adopting the proposed fleet average NMOG+NOx standards. These

are consistent with those set for the LEV III MDV program in model years 2018 

and later. As proposed, we are also adopting provisions allowing manufacturers to

voluntarily meet bin and fleet average standards in model years 2016 and 2017 that 

are consistent with the MDV LEV III standards in those years, for the purpose of 

generating credits that can be used later or traded to others. These voluntary

standards are shown in Table IV-13. This voluntary opt-in program serves the 

important purpose of furthering consistency between the federal and California 

programs, such that manufacturers who wish to can produce a single vehicle fleet 

for sale nationwide, with the opportunity for reciprocal certification in affected 

model years. It further incentivizes pulling ahead of Tier 3 technologies, with 

resulting environmental benefits, by providing for early compliance credits in this 

nationwide fleet. Commenters expressed support for this harmonized array of HDV 

emissions standards.

Manufacturers choosing to opt into this early compliance program could 

start in either model year 2016 or 2017. They would have to meet the full 

complement of applicable bin standards and requirements for the bins they choose 

for their vehicles in meeting the 2016/2017 MY fleet average FTP NMOG+NOX

standards, including SFTP standards in the bins that have SFTP standards. 

However, they do not need to meet the Tier 3 PM FTP and SFTP standards 

discussed in Sections IV.B.2.d and IV.B.3.a, or the evaporative emissions standards 

discussed in Section IV.C, because these requirements phase in on a later schedule. 

We are not extending the voluntary compliance opportunity to the 2015 model year, 

based on manufacturer comments indicating it would be of little value.

Table IV-13 HDV Fleet Average NMOG+NOX Standards (mg/mi)

Voluntary Required Program

Model 

Year 2016 2017 2018 2019 2020 2021 2022 and later

Class 2b 333 310 278 253 228 203 178
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Class 3 548 508 451 400 349 298 247

 

We believe that the voluntary program provisions will benefit the 

environment, the regulated industry, and vehicle purchasers, because it has potential 

to accomplish early emissions reductions while maintaining the goal of a costeffective, nationwide vehicle program in every model year going forward.

Although manufacturers will be allowed to meet the fleet average 

NMOG+NOX standard through whatever combination of bin-specific vehicles they

choose, it is instructive to note that the fully phased in fleet average standard for 

model years 2022 and later will be the equivalent of a Class 2b fleet mix of 90 

percent Bin 170 and 10 percent Bin 250 vehicles, and a Class 3 fleet mix of 90 

percent Bin 230 and 10 percent Bin 400 vehicles. Therefore, it is appropriate to 

consider Bin 170 Class 2b vehicles and Bin 230 Class 3 vehicles to be 

representative of Tier 3-compliant HDVs in the long term.

c. Alternative NMOG+NOX Phase-in

We believe the fleet average phase-in described above will be flexible, 

effective, and highly compatible with manufacturers’ desire to market vehicles 

nationwide, because of its close alignment with California’s LEV III program for 

medium-duty vehicles. However, for any HDV manufacturers seeking four years 

of lead time and three years of stability as specified in Clean Air Act section 

202(a)(3)(C), we proposed an alternative compliance path.340 This alternative 

approach was crafted to be equivalent to the NMOG+NOX declining fleet average 

in the above-described LEV III-harmonized alternative in every model year, except 

that the period for the voluntary program in the alternative approach would extend 

an extra model year—through 2018. To ensure that this approach meets the Act’s 

stability requirement, instead of being structured around an annually declining fleet 

average standard, the alternative approach requires a manufacturer to demonstrate 

compliance (including through use of credits) with a schedule of annually 

increasing percent-of-sales of HDVs certified to the fully phased in 178 mg/mi 

(Class 2b) and 247 mg/mi (Class 3) standards, as shown in Table IV-14. We are 

adopting the alternative percent-of-sales phase-in largely as proposed, with limited 

changes described below.

 

340 For vehicles above 6,000 lbs GVWR, Clean Air Act section 202(a)(3)(C) requires EPA to provide 

manufacturers with a minimum of 4 years of lead time before mandatory changes to any standard 

applicable to hydrocarbon, NOX, carbon monoxide, or PM can be implemented, and 3 years of 

stability between changes to any such standard.
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Table IV-14 Percent-of-Sales Alternative NMOG+NOX Phase-in

Voluntary Required Program

Model 

Year 2016 2017 2018 2019 a

2020 2021 2022 and later

Class 2b 29% 39% 54% 65% 77% 88% 100%

Class 3 21% 32% 47% 60% 73% 87% 100%

a Special provisions apply to models with an early-starting 2019 model year.

The availability of emissions averaging under our alternative phase-in, 

discussed below, makes the two alternatives functionally equivalent, not just in the 

annual emissions reductions they achieve, but also in how manufacturers may

design their mix of products to meet the phase-in standards. Commenters who 

disagreed with this assessment for HDVs did not provide their reasoning, beyond 

referring to similar comments they had on the parallel light-duty (above 6000 lbs 

GVWR) alternative phase-in. However, that proposed alternative differs from the 

one we proposed for HDVs, and the elements in it that were found objectionable by

the manufacturers are not in the HDV alternative. (See Section IV.A.3 for 

discussion of comments on the light-duty alternative.) 

Commenters objected that the proposed percent-of-sales alternative has not 

been shown by EPA to be feasible, or in fact is infeasible because it mandates the 

early phase-in of low-emitting vehicles certified to the final standards. Such 

comments miss the fact that, with ABT, every manufacturer can produce the same 

mix of vehicles in any model year to comply with either HDV phase-in alternative, 

with the exception that MY 2018 is a voluntary phase-in year under the alternative 

phase-in and a required year under the LEV III-harmonized phase-in. The ABT 

provisions enable a manufacturer to adopt a fleet average compliance strategy while 

utilizing the percent-of-sales phase-in that is identical to what would be required 

under the LEV III-harmonized phase-in’s fleet average standards. By no means are 

manufacturers forced to make only vehicles certified to the final standards. The 

percent-of-sales phase-in is thereby no more stringent than the LEV III-harmonized 

phase-in, and the feasibility analysis provided in Section IV.B.5, which expressly

addresses the LEV III-harmonized phase-in, serves to demonstrate the feasibility of 

both alternatives. 

Some comments seem to assert that the percent-of-sales framework for the 

alternative was chosen by EPA to make this alternative so stringent (by requiring 

some vehicles to meet final standards four years early) that no reasonable company 

would use it. This is incorrect, both in regard to its actual effect (which as 

explained above is not more stringent), and in regard to our intent. The percent-of-
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sales framework for the alternative was proposed and is being adopted for the 

purpose of providing manufacturers with a phase-in alternative that explicitly meets 

the applicable Clean Air Act stability requirement.

We are making one change to the percent-of-sales alternative, necessitated 

by the fact that this final rule is being signed in 2014, not 2013 as envisioned in the 

proposal. HDV models for which the 2019 model year begins before the fourth 

anniversary of the signature date of this final rule may be excluded from the Tier 3 

fleet average compliance calculations and all other Tier 3 requirements. These 

excluded vehicles would instead need to comply with the applicable pre-Tier 3 

standards and requirements for the entire production of these models throughout the 

2019 MY. This limited allowance ensures that the alternative meets EPA’s 

obligation for four years of lead time under the Clean Air Act. It is similar to a 

phase-in alternative we provided in the light-duty vehicle Tier 2 rule (see 65 FR 

6747, February 10, 2000). Note that 40 CFR 86.1803-01 defines “model year” as 

“the manufacturer’s annual production period (as determined by the Administrator) 

which includes January 1 of such calendar year: Provided that if the manufacturer 

has no annual production period, the term ‘model year’ shall mean the calendar 

year.” Additional regulations pertaining to the definition of a model year are in 40 

CFR 85, subpart X.

This allowance remains optional within the percent-of-sales alternative-- a 

manufacturer may voluntarily include these early-starting 2019 MY vehicles in the 

Tier 3 program, and in this case these vehicles would be treated no differently under 

the alternative than vehicles with a later-starting 2019 MY, including with regard to 

whether manufacturers choose to make them part of the “phase-in” fleet (vehicles 

counting toward the phase-in percentages) or the “phase-out” fleet (vehicles not 

counting toward the phase-in percentages).

Although it is conceivable that manufacturers would commence an early 

start of the 2019 model year specifically for the purpose of delaying Tier 3 

obligations, we do not think this is likely, given the many important constraints and 

decisions that typically factor into setting this date, and the fact that signature of this

final rule is occurring relatively early in the calendar year, well before typical 

model year start dates. We believe this is a reasonable way to provide a viable 

percent-of-sales phase-in alternative that has four years of lead time without making 

the 2019 model year voluntary for all vehicles or putting new constraints on the 

timing of a manufacturer’s model year.

To help ensure that the percent-of-sales alternative is fully equivalent to the 

LEV III-harmonized alternative in terms of fleet-wide emissions control and 

technology mix choices, we are including some additional provisions, as proposed. 

First, the Tier 3 vehicles being phased in under the percent-of-sales alternative, in 

addition to meeting the fully phased-in FTP NMOG+NOX standards, must also 

meet all other FTP and (as described below) SFTP standards required by the LEV 
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III-harmonized alternative. These include the CO and formaldehyde FTP standards, 

the 150,000 mile (15 year) useful life requirement, exhaust emissions testing with 

the new test fuel for gasoline- and ethanol-fueled vehicles discussed in Section 

IV.F, and the NMOG+NOX and CO SFTP standards in Table IV-15. The specific 

standards are those for the bins in these tables closest to the fully phased-in 

NMOG+NOX standards: Bin 170 for Class 2b and Bin 230 for Class 3. (The PM 

and evaporative emissions standards phase in on separate schedules under both 

alternatives, as discussed in Sections IV.B.2.d and IV.C.)

Second, we are making an ABT program available for the percent-of-sales 

alternative, structured like the one created for the LEV III-harmonized alternative. 

This involves certifying the vehicles in a manufacturer’s HDV fleet to the bin 

standards, and demonstrating compliance with the fleet average standards for the 

LEV III-harmonized alternative in each model year, including through the use of 

ABT credits as in the LEV III-harmonized alternative. We are using the fleet 

average calculation method for purposes of ABT because, as explained above, we 

have determined that making this demonstration is equivalent to demonstrating 

compliance with the percent-of-sales requirement, and we see no value in 

complicating the program with another set of calculations.

However, we are establishing one difference between the LEV IIIharmonized and percent-of-sales alternatives with respect to ABT provisions. 

Unlike in the LEV III-harmonized alternative, manufacturers will not have to 

certify all vehicles into bins in order to take advantage of the ABT provisions under 

the percent-of-sales alternative. Rather they could choose to certify any “phaseout” vehicles (that is, those not counting toward the percent-of-sales phase-in) to the 

pre-Tier 3 NMHC and NOX standards, provided these vehicles do not have family

emission limits (FELs) above those standards. These non-Tier 3 vehicles will not 

be subject to the Tier 3 standards or other vehicle-specific elements of the Tier 3 

compliance program. There were no comments on these specific compliance and 

ABT provisions associated with the percent-of-sales alternative.

d. Phase-in of PM Standards

Consistent with the light-duty Tier 3 program discussed in Section IV.A, we 

are phasing in the PM standards for HDVs as an increasing percentage of a 

manufacturer’s production of chassis-certified HDVs (combined Class 2b and 3) 

per year. In addition to concerns regarding the availability and required upgrades of 

test facilities used for both light-duty and heavy-duty vehicle testing, manufacturers 

have expressed uncertainty about PM emissions with new engine and emissions 

control technologies entering the market as a result of new greenhouse gas (GHG)

standards. Therefore we are adopting the same phase-in schedule as for the lightduty sector in model years 2018-2019-2020-2021: 20-40-70-100 percent, 

respectively. This will apply to HDVs certified under either NMOG+NOX phase-in 

alternative. The California Air Resources Board (CARB) is phasing in the LEV III 
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PM standards for HDVs on the same schedule, except that LEV III will also involve 

a 10 percent PM phase-in in the 2017 model year. We asked for comment on our 

adding this to our voluntary program for 2017, but received no comments on it and 

are not including it in the Tier 3 program.

For manufacturers choosing the declining fleet average NMOG+NOX

compliance path, the PM phase-in requirement for HDVs will be completely

independent of the NMOG+NOX phase-in, with no requirement that both phase-ins

be met on the same vehicles. As a result, vehicles certified to any of the bin 

standards for NMOG+NOX need not necessarily meet Tier 3 PM standards before 

the 2021 model year. Instead, the current 0.02 g/mi PM standard will apply for 

those vehicles not yet phased into the Tier 3 PM standards. We are requiring that 

manufacturers choosing the percent-of-sales phase-in alternative for NMOG+NOX

meet the PM phase-in requirements with only those vehicles certified to the Tier 3 

NMOG+NOX standard, except in the 2019 and earlier model years when the 

standards, including the PM standards, are voluntary, and in the 2021 model year 

when the 100 percent PM phase-in requirement exceeds the 87-88 percent 

NMOG+NOX phase-in requirement. This is appropriate given the ability of 

manufacturers to build “phase-out” vehicles (those not counting toward the phase-in

percentages) under the percent-of-sales NMOG+NOx alternative that are certified 

entirely to pre-Tier 3 standards while still participating in the Tier 3 ABT program, 

discussed above.

We will consider any vehicle under either compliance path that is not 

certified to Tier 3 standards for PM and NMOG+NOX (as well as the other, 

concomitant Tier 3 standards and requirements such as the extended useful life), an 

“interim Tier 3” vehicle. This term also applies to vehicles certified in one of the 

interim bins, as discussed above.

Note that compliance with Tier 3 evaporative emissions requirements 

follows a separate phase-in schedule as described in Section IV.C. As a result, a 

vehicle in an exhaust emissions family that the manufacturer has phased in to the 

new useful life and test fuel requirements may be in an evaporative emissions 

family that has not yet phased in the Tier 3 useful life and test fuel for evaporative 

emissions compliance and testing.

i. Optional PM Phase-in

The percent-of-sales phase-in schedule for the PM standard, described 

above, will allow manufacturers with multiple vehicle models to determine and plan 

the phase-in of those models based on anticipated sales volumes of each model. 

However, manufacturers certifying only a few vehicle models may not be able to 

take meaningful advantage of this schedule. This is because their limited number of 

models may force them to over-comply to reach the required minimum percentages, 
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compared to a manufacturer with many vehicle models available from which to 

choose a phase-in pathway.

For instance, a manufacturer with only two models that each equally

account for 50 percent of its sales would be required to introduce (at least) one of 

the models in MY 2018 to meet the phase-in requirement of 20 percent in the first 

year. At the 50 percent level, this model would then also meet the requirements for 

MY 2019 (40 percent). To meet the MY 2020 requirement of 70 percent of sales, 

however, the manufacturer would need to introduce the second Tier 3 vehicle that 

year. Thus the manufacturer would have introduced 100 percent of its Tier 3 

models one year earlier compared to a manufacturer that was able to delay the final 

30 percent of its fleet until MY 2021 by distributing its redesign of models over the 

entire phase-in period.

To provide for more equal application of this benefit among all 

manufacturers in the early years of the program, we are adopting the proposed

optional “indexed” phase-in schedule that could be used by a manufacturer to meet 

the phase-in requirements. A manufacturer that exceeds the phase-in requirements 

in any given year will be allowed to, in effect, offset some of the phase-in 

requirements in a later model year. The optional phase-in schedule will be 

acceptable if it passes a mathematical test. The mathematical test is designed to 

provide manufacturers a benefit from certifying to the standards at higher volumes 

than they are obligated to under the normal phase-in schedule, while ensuring that 

the overall population of complying vehicles at the end of the phase-in is roughly 

the same as under the fixed percentage approach. In this alternative approach, 

manufacturers will weight Tier 3 PM-compliant vehicles in the earlier years by 

multiplying their percent phase-in by the number of years prior to MY 2022 (that is, 

the second year of the 100 percent phase-in requirement). 

The mathematical equation for applying the optional phase-in is as follows:

(4 x APP2018) + (3 x APP2019) + (2 x APP2020) + (1 x APP2021) ≥ 440, 

where APP is the actual phase-in percentage for the referenced model year. The 

sum of the calculation will need to be greater than or equal to 440, which is the 

result when the optional phase-in equation is applied to the primary percent phasein schedule (4 x 20% + 3 x 40% + 2 x 70% + 1 x 100% = 440). Commenters 

supported this optional PM phase-in approach.

3. Supplemental FTP Standards for HDVs

Unlike passenger cars and light trucks, HDVs are not currently subject to 

SFTP standards. SFTP standards are intended to ensure vehicles have robust 

emissions control over a wide range of real-world driving patterns not well-covered 

by the FTP drive cycle. Even though HDVs are not typically driven in the same 
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way as passenger cars and LDTs, especially as they frequently carry or tow heavy 

loads, we believe some substantial portion of real world heavy-duty pickup and van 

driving is not well-represented on the FTP cycle.

The goal in setting the SFTP standards levels is not to force manufacturers 

to add expensive new control hardware for off-FTP cycle conditions, but rather to 

ensure a robust overall control program that precludes high off-FTP cycle emissions 

by having vehicle designers consider them in their choice of compliance strategies. 

High off-FTP cycle emissions, even if encountered relatively infrequently in realworld driving, could create a substantial inadequacy in the Tier 3 program, which 

aims to achieve very low overall emissions in use. The SFTP provisions will also 

help make the HDV program more consistent with the heavy-duty engine program, 

which for several years has included “not-to-exceed” provisions to control off-cycle 

emissions. Therefore, in addition to the SFTP provisions, we are further limiting 

enrichment on spark ignition engines in all areas of operation unless absolutely

necessary.

a. SFTP NMOG+NOX, PM and CO Standards

The SFTP standards levels are provided in Table IV-15. These are 

consistent with those adopted in the LEV III program.

Table IV-15 SFTP Standards for HDVs

Vehicles in 

FTP Bins:

NMOG+NOX

(mg/mi)

PM

(mg/mi)

CO

(g/mi)

Class 2b with hp/GVWR ≤ 0.024 hp/lb:a

FTP Bins 200, 250 550 7 22.0

FTP Bins 150, 170 350 7 12.0

Class 2b:

FTP Bins 200, 250 800 10 22.0

FTP Bins 150, 170 450 10 12.0

Class 3:

FTP Bins 270, 400 550 7 6.0

FTP Bins 200, 230 350 7 4.0

a These standards apply for vehicles optionally tested using emissions from only the highway portion 

of the US06 cycle. 

We are linking Tier 3 SFTP implementation for HDVs directly to the Tier 3 

FTP phase-in and bins for these vehicles. That is, an HDV certified to any of the 

Tier 3 FTP bin standards must meet the SFTP standards for that bin as well. 

However, because the FTP PM standard phases in on a separate schedule, we will

require that SFTP PM compliance be linked to the same schedule. That is, an HDV 

certified to the Tier 3 FTP PM standard must meet the applicable SFTP PM 
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standard as well. This approach recognizes the complementary nature of FTP and 

SFTP provisions and helps to ensure that Tier 3 emissions controls are robust in real 

world driving. CARB expressed support in its written comments for this approach 

to linking FTP and SFTP requirements and an intent to propose aligning LEV III 

with it once the Tier 3 program is finalized.

There are no SFTP requirements for the interim Tier 3 bins in each class 

(Class 2b Bins 340 and 395 and Class 3 Bins 570 and 630), because these are 

essentially carry-over bins from the previous standards to help facilitate the 

transition to Tier 3, and therefore are not intended to take on new requirements that 

might prompt a redesign. These implementation provisions are consistent with the 

approach taken in the LEV III program, except that California applies more of the 

Tier 3 requirements for SFTP and extended useful life to vehicles in the interim 

bins.

To help ensure a robust SFTP program that achieves good control over a 

wide range of real world conditions, we proposed to use a weighted-average 

composite SFTP cycle, with NMOG+NOX emissions calculated from results of 

testing over three cycles: the US06, the FTP, and the SC03, weighting these results 

by 0.28, 0.35, and 0.37, respectively. However, at proposal, we determined that the 

full US06 component of the composite cycle, along with the ALVW loaded test 

condition, would not be sufficiently representative of real-world driving for two 

groups of HDVs: those with low power-to-weight ratios and Class 3 vehicles.

Therefore, as discussed in the proposal, SFTP testing of Class 2b vehicles 

with power-to-weight ratios at or below 0.024 hp/lb, may, at the manufacturer’s

option replace the full US06 component of the composite SFTP emissions with the 

test results from only the second of the three emissions sampling bags in the US06 

test, generally referred to as the “highway” portion of the US06. HDVs so tested 

will be subject to the correspondingly lower SFTP standards levels shown in the 

table above. These vehicles will be driven during the test in the same way as the 

higher power-to-weight Class 2b vehicles (over the full US06 cycle), using best 

effort (maximum power) if the vehicle cannot maintain the driving schedule. The 

large majority of Class 2b vehicles-- those with power-to-weight above 0.024 hp/lb 

--will be required to include emissions over the full US06 cycle in the composite 

SFTP. We believe that this approach provides a robust but repeatable and reliable 

test for the full range of Class 2b vehicles, as the highway portion of the US06 

retains broad coverage of vehicle speed/acceleration combinations measured in realworld driving. Any testing conducted by EPA would follow the manufacturer’s test 

path for the vehicle.

For Class 3 vehicles, which range up to 14,000 lbs GVWR, we are also 

concerned that the full US06 cycle would not provide a representative drive cycle 

for SFTP testing. These vehicles are much larger than the light-duty vehicles that 

formed the basis for development of the US06 cycle, and loading them to ALVW 
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for the SFTP test yields a very heavy test vehicle, not likely to be safely driven in 

the real world in a manner that is typified by this aggressive cycle. We believe that 

the LA-92 (or “Unified”) driving cycle developed by CARB is more representative 

of Class 3 truck driving patterns and will produce more robust results for use in 

SFTP evaluations. Therefore we are adopting the proposed LA-92 cycle for use in 

place of the US06 component of the composite SFTP for Class 3 HDVs. 

HDVs do not have SC03 emissions requirements under the current HDV 

standards. Manufacturers of HDVs have indicated that they expect the SC03 

emissions to be consistently lower than either the US06 or the FTP emissions 

levels, and therefore the added SC03 testing burden may be unnecessary. We are 

therefore providing HDV manufacturers with the option to substitute the FTP 

emissions levels for the SC03 emissions results for purposes of compliance. 

However, we will retain the ability to determine the composite emissions using 

SC03 test results in confirmatory or in-use testing. We received no adverse 

comments on this proposed approach.

The set of composite SFTP cycles and standards we proposed and are 

adopting for HDVs is consistent with the MDV LEV III program. We received no 

adverse comments on them, except with regard to in-use testing as discussed in 

Section IV.B.6.a.

b. Enrichment Limitation for Spark-Ignition Engines

To prevent emissions from excessive enrichment in areas not fully 

encountered in the SFTP cycles, we proposed and are adopting limitations in the 

frequency and magnitude of enrichment episodes for spark-ignition HDVs. These 

limitations are identical to those for light-duty vehicles. See Section IV.A.4.c for 

discussion of the requirements and relevant comments received.

4. HDV Emissions Averaging, Banking, and Trading

This section describes how exhaust emissions credits may be earned and 

used. See Section V.C for similar provisions that apply for evaporative emissions. 

We are continuing the practice of allowing manufacturers to satisfy standards 

through the averaging of emissions, as well as through the banking of emissions 

credits for later use and the trading of credits with others.

There are a number of facets of the Tier 3 ABT program for HDVs that are

different from the existing program. First, instead of separate NMHC and NOX

credits, manufacturers earn combined NMOG+NOX credits, consistent with the 

form of the standards.

Second, manufacturers may accrue a deficit in their credit balance. Deficits 

incurred in a model year may be carried forward but a manufacturer will not be 
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permitted to have a negative overall HDV credit balance in more than 3 consecutive 

model years. Manufacturers will have to use any new credits to offset any shortfall 

before those credits can be traded or banked for additional model years. Credits not

used within 5 years after they are earned will be forfeited. These 5/3-year 

credit/deficit life provisions are consistent with our light-duty Tier 3 approach, the 

California LEV III program for MDVs, and EPA programs for controlling GHG 

emissions from light- and heavy-duty vehicles.

Third, as part of our new requirement for chassis certification of complete 

diesel HDVs, we are allowing the chassis-certified diesel HDVs to participate in the 

Tier 3 ABT program without restriction. Prior to Tier 3 they have not been allowed 

to earn or use ABT credits. We are not restricting or adjusting credit exchange 

between diesel and gasoline-fueled HDVs, consistent with our shift to combined 

NMOG+NOX standards that helps to ensure comparable stringency for these two 

engine types, and consistent also with the LEV III MDV program.

Credits earned by a chassis-certified Tier 3 HDV may be used to 

demonstrate compliance with NMOG+NOX standards for any other chassiscertified Tier 3 HDV, regardless of size and without adjustment. This effectively

allows manufacturers to plan a comprehensive HDV compliance strategy for their 

entire Class 2b and Class 3 product offering, by balancing credits so as to 

demonstrate compliance with the standards for both classes.

Industry commenters argued that EPA should align the HDV credit 

provisions with the light-duty program by allowing early Tier 3 credits to be 

generated in MYs 2016 and 2017, calculated relative to the highest Class 2b and 

Class 3 bin NMOG+NOx levels (395 and 630 mg/mi, respectively), and capped at a 

level proportional to the California level in MY 2018. However, these highest bin 

levels correspond to those of the existing HDV standards for NMHC and NOx, and 

are significantly higher than the MY 2016 and 2017 LEV III levels. Thus vehicles 

designed to just meet the LEV III standards in these years could generate a large 

preliminary number of credits under the industry’s Tier 3 early credits proposal, 

credits they would not earn in LEV III, thereby potentially thwarting the 

harmonization of the two programs. Truncating that credit bank for each 

manufacturer in 2018 such that it is proportional to their LEV III balance could 

perhaps, with additional restrictions on trading and banking, restore a harmonized 

credit status in that year. However, it constitutes an unnecessarily complex and 

uncertain pathway to the same result as that achieved under EPA’s early opt-in 

provisions.

Commenters requested that we provide for the conversion of pre-Tier 3 

HDV credits for use in Tier 3. However, as discussed in the proposal, we are not 

including provisions for doing so. We believe that by providing an early Tier 3 optin program for HDVs, capable of generating credits for two model years before the 

mandatory standards take effect (even longer under the alternative percent-of-sales 
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phase-in approach), we are giving ample opportunity for the manufacturers to 

accumulate early credits.

Manufacturers commented that the proposed fleet average compliance 

approach is incongruous with California’s LEV III method based on vehicle 

equivalent credits (VECs). Although expressing that they have no preference for 

the method since the stringency is equivalent, they recommended that EPA foster 

harmonization by providing a compliance option based on VECs. We believe that 

such an option would add unnecessary complexity to the Tier 3 program, and is 

made even more unnecessary by the intent expressed in CARB’s written comments

to propose a fleet average option for LEV III that is identical to EPA’s approach.

In the past we have set upper bounds, called family emission limit (FEL) 

caps, on how high emissions can be for credit-using vehicles, regardless of how 

many credits might be available. Under our Tier 3 bin structure, we believe that 

exhaust emission FEL caps are no longer relevant for Tier 3 HDVs, as every vehicle 

must meet whatever standards apply in the bin chosen for the vehicle by the 

manufacturer. (The bin standard becomes the effective FEL.) Indeed, because 

credits and deficits are calculated based on the difference between a manufacturer’s 

fleet average emissions and the fleet average standards for a given model year, 

credits are not calculated for individual vehicle families at all. Thus the standard

for NMOG+NOX in the highest allowable bin serves the purpose of the FEL caps in 

previous programs.

Consistent with our proposal, we are not creating an averaging program for 

the HDV SFTP program, because we believe that the bin structure and FTPcentered NMOG+NOX ABT program provide adequate flexibility for smooth 

program implementation, especially in light of our aim to have the FTP standards 

be the primary technology forcers. A separate ABT program for SFTP compliance 

would add substantial complexity with little benefit, and, by making it possible to 

demonstrate robust SFTP emissions control on a vehicle that lacks commensurate 

FTP control, could prove at odds with the primary goal of the supplemental test for 

HDVs.

5. Feasibility of HDV Standards

The feasibility assessment, discussed in more detail in Chapter 1 of the RIA, 

recognizes that the Tier 3 program is composed of several new requirements for 

Class 2b and 3 heavy-duty vehicles, which include primarily large gasoline and 

diesel pick-up trucks and vans with diverse application-specific designs. These new 

exhaust emissions requirements include stringent NMOG+NOX and PM standards 

for the FTP and the SFTP, that will as a whole require new emissions control 

strategies and hardware in order to achieve the standards. The type of new 

hardware that will be required will vary depending on the specific application and 

emissions challenges. Additionally, gasoline and diesel vehicles will require 
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different emissions control strategies and hardware. The level of stringency for the 

SFTP NMOG+NOX standards will generally only require additional precise control 

of the engine parameters not necessitated in the past because of the lack of SFTP 

requirements. Similarly, the new PM standards on both the FTP and SFTP cycles 

will require more precise control of engine operation on gasoline vehicles while 

diesels already equipped with diesel particulate filters will require minimal changes. 

The new PM standards may also require that manufacturers consider the durability

of their engines to the 150,000 miles useful life requirement with respect to engine 

wear resulting in increased oil consumption and potentially higher PM emissions.

In order to assess the technical feasibility of NMOG+NOX national fleet 

average FTP standards of 178 mg/mi for Class 2b vehicles and 247 mg/mi for Class 

3 vehicles, we conducted an analysis of certification data for the HDVs certified in 

the 2010 and 2011 MYs. For this final rule, we also reviewed certification records 

for 2012 and 2013 MY vehicles, and determined that these primarily involve 

carryover engines and emission control hardware. Therefore we did not update the 

NPRM analysis however any new or updated certification results in the 2012 or 

2013 MYs are included in the RIA chapter 1 discussion. This analysis provided a 

baseline for the current HDV fleet emissions performance, as well as the emissions 

performance specific to the Class 2b and 3 vehicles. The emissions performance of 

each heavy-duty vehicle class specific to gasoline and diesel is shown in Table 

IV-16 below. It is important to note that the emissions results are only the 4000 

mile test point results and do not incorporate any deterioration which manufacturers 

must account for when certifying to a full useful life standard. Designs limiting the 

deterioration of emission control hardware are critical to meeting the emission 

standards at the useful life of the Tier 3 program. Deterioration factors to adjust the 

values to the Tier 3 useful life standard of 150,000 miles were not available.

However, deterioration factors to adjust to 120,000 miles useful life, and their 

implications for performance at higher miles, are discussed in the RIA Chapter 1. 

The analysis also reflects the importance of the combined NMOG+NOX

standard approach, where diesels and gasoline HDVs can balance their combined 

NMOG and NOX levels. Diesel vehicles in the analysis produce very low NMHC 

emissions (NMOG is not reported for diesels) but higher NOX emissions, while 

gasoline vehicles have opposite performance. The combined standard allows 

manufacturers to determine the proper balance of the unique emissions challenges 

of a diesel or gasoline vehicle.

Table IV-16 2010/11 Certification Test Results at 4000 Miles

NMHC NMOG NOX CO NMOG+NOX

Gasoline Class 2b 0.050 0.052 0.041 1.648 0.092

Class 3 0.080 0.083 0.073 2.373 0.156

NMHC+NOX
Page 188 of 529

Diesel Class 2b 0.037 0.138 0.195 0.174

Class 3 0.019 0.249 0.158 0.268

Combined Class 2b 0.043 0.026 0.089 0.922 0.133

Combined Class 3 0.050 0.041 0.161 1.265 0.212

Manufacturers typically certify their vehicles at emissions levels well below 

the numerical standards. This difference is referred to as “compliance margin” and 

is a result of manufacturers’ efforts to address all the sources of variability that 

could occur during the certification or in-use testing processes and during in-use 

operation. These sources of variability include: test-to-test variability, test 

location, build variation and manufacturing tolerances, vehicle operation (for 

example: driving habits, ambient temperature, etc.), and the deleterious effects of 

sulfur and other oil and fuel contaminants. To meet the NMOG+NOX standard of 

178 mg/mi for Class 2b and 247 mg/mi for Class 3 vehicles and establish a 

compliance margin for these sources of variability, manufacturers will need to 

reduce their emission levels considerably from the levels indicated in this data set, 

particularly for diesel vehicles.

However, as discussed above, these emission results do not include the 

expected emissions deterioration which will be determined by manufacturers during 

development and certification testing. Therefore, manufacturers will need to further 

reduce emissions levels in anticipation of the unavoidable emissions deterioration 

that will occur during the useful life of the vehicle. Further, deterioration is a 

function of several factors, but it is predominantly due to emissions control 

hardware thermal exposure (high temperatures), which is typically a significant 

issue on vehicles used for performing work like Class 2b and 3 vehicles. 

We also expect that the 2011 heavy-duty GHG rule will present new 

challenges to manufacturers’ emissions performance goals as vehicles begin to use 

new engines designed to meet the new GHG requirements.341 Some of these new 

technologies may result in emissions challenges that are specific to certain 

operating conditions. For example, downsized gasoline engines will likely have 

improved FTP exhaust emissions but have increased challenge with the high-load 

SFTP requirements. Diesel-fueled vehicles may need to carefully balance engine 

controls which reduce GHG emissions but can increase criteria emissions (NOX).

With regard to the ability of the heavy-duty fleet to meet the PM standards 

for the FTP and the SFTP, we based our conclusions on some testing of current 

 

341 76 FR 57106 (September 15, 2011).
Page 189 of 529

heavy-duty gasoline vehicles (HDGVs) and the PM performance of the existing 

light–duty fleet with similar engines. Testing of two HDGVs with the highest sales 

volume (Ford F250 and Chevrolet Silverado 2500), albeit not aged to full useful 

life, confirmed that they have similar PM emissions levels as the light-duty 

counterparts and therefore also meet the standards for both the Class 2b and Class 3 

configurations. Data from light-duty gasoline vehicles with similar or common 

engines with their heavy-duty “sister” vehicle models demonstrates that these 

vehicles are currently meeting the Tier 3 FTP PM standards at the Tier 2 useful life 

mileage of 120,000 miles. Heavy-duty diesel vehicles all are equipped with DPFs 

and have no challenges meeting the FTP or SFTP PM standards being set for Tier 3. 

The SFTP test data from the same two heavy-duty vehicles described above 

indicates that gasoline vehicles can achieve the standards for SFTP NMOG+NOX

and PM. Since heavy-duty vehicles are not currently required to comply with any 

of the SFTP requirements, manufacturers have not focused on improving the 

emissions performance specifically over the SFTP cycles (US06, LA-92, and 

SC03). Therefore, although the limited testing results had a high degree of 

variability, several tests met the PM standards for the high power-to-weight Class 

2b vehicles. Consistent with light-duty, vehicles that are demonstrating high PM on 

the US06 will need to control enrichment and oil consumption from engine wear. 

Recently manufacturers have already been implementing product changes to reduce 

oil consumption to address both customer satisfaction issues and to reduce cost of 

vehicle ownership.

Given the technologies likely to be applied to meet the HDV exhaust 

emissions standards, discussed below, we consider the lead time available before 

the standards take effect under all of the alternatives to be sufficient. HDV 

manufacturers are already adopting some of the complying technologies, especially

for their light-duty vehicles, and these can readily be adapted for heavy-duty

applications. In addition, manufacturers have already begun developing these 

technologies for HDVs, including diesels, in response to California’s recently

adopted LEV III MDV standards which begin to take effect in the 2015 model year. 

Finally, as described above in Sections IV.B.2, IV.B.3, and IV.B.4, our program 

incorporates a number of phase-in and alternative compliance provisions that will

ease the transition to final standards without disrupting heavy-duty pickup and van 

product redesign cycles. Among these is an alternative phase-in that does not begin

mandatory standards until model year 2019.

Comments we received on the proposed HDV standards did not specifically 

address our analysis of their technical feasibility. The Manufacturers of Emission 

Controls Association (MECA) outlined diesel and gasoline-engine technologies that 

they expect will be used to achieve the Tier 3 standards cost-effectively, generally 

consistent with our draft RIA. Vehicle and engine industry commenters argued that 

the case we made for feasibility relied too heavily on extending light-duty truck test 

data, supplemented by testing of only two HDVs, neither of which were fully aged 
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or representative of future vehicles designed to meet our new GHG standards. 

However, commenters did not question the feasibility, durability, implementability, 

or effectiveness of the technologies we identified, or their ability to achieve the 

proposed standards. Instead, the focus of these comments was on statutory 

provisions for lead time and stability, and on how relaxed standards for in-use 

testing and testing at high altitudes would help to implement the standards within 

the allotted lead time. These issues, including changes we are making in response 

to the comments, are addressed in Sections IV.B.2.c, IV.B.6.a, and IV.B.6.f.

i. Technologies Likely to be Applied

The technologies expected to be applied to vehicles to meet the lower 

standards levels will address the emissions control system’s ability to control 

emissions during cold start. Current vehicle emissions control systems depend on 

the time it takes for the catalyst to light-off, which is typically defined as the 

catalyst reaching a temperature of 250 °C. While the specific emissions challenge 

is somewhat different for gasoline engines than for diesel engines, achieving the 

necessary temperatures in the catalysts is a common challenge. In order to improve 

catalyst light-off, the manufacturers will likely add technologies that provide heat 

from combustion more readily to the catalyst or improve the catalyst efficiency at 

lower temperatures. These technologies could include calibration changes, thermal 

management, close-coupled catalysts, catalyst Platinum Group Metal (PGM)

loading, and possibly secondary air injection. In some cases, where the catalyst 

light-off response and efficiency are not enough to address the cold start emissions, 

hydrocarbon adsorbers may be applied to trap hydrocarbons until such time that the 

catalyst is lit-off. Note that with the exception of hydrocarbon adsorbers each of 

these technologies addresses both NMOG and NOX performance. Key potential 

technologies are described in greater detail below.

 Engine Control Calibration Changes – These include changes to retard 

spark and/or adjust air/fuel mixtures such that more combustion heat is 

created during the cold start on gasoline engines. Diesel engines may

use unique injection timing strategies or other available engine control 

parameters. Engine calibration changes can affect NMOG, NOX and PM 

emissions.

 Thermal Management – This technology includes all design attributes 

meant to conduct the combustion heat into the catalyst with minimal 

cooling on both gasoline and diesel engines. This includes insulating the 

exhaust piping between the engine and the catalyst, reducing the wetted 

area of the exhaust path and/or reducing the thermal mass of the exhaust 

system. Close-coupling of catalysts (packaging the catalysts as close to 

the head of the engine as possible to mitigate the cooling effects of 

longer exhaust piping) can also be effective, but is more difficult to 

employ than in light-duty applications because of durability concerns 
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with highly loaded operation and the potential increase in fuel 

consumption to protect the catalyst from high temperatures.

 Catalyst PGM Loading – Additional PGM loading in the catalyst 

provides a greater number of sites to catalyze emissions and addresses 

NMOG, NOX and PM emissions.

 Selective Catalytic Reduction Optimization – Diesel applications will 

continue to refine this NOX emissions control strategy through improved 

hardware design and implementation in vehicle applications. Additional 

engineering enhancements in the control of the SCR system and related 

processes will also help reduce emissions levels.

6. Other HDV Provisions

a. In-Use Emissions

The proposal requested comment on the need for relaxation of NMOG+NOx 

and PM standards for in-use vehicle testing. The LEV III program includes these 

on an interim basis in the more stringent bins in both FTP and SFTP testing. 

However, in its written comments, CARB expressed the view that the technologies 

required for SFTP compliance are well-established, and that sufficient lead time is 

provided such that interim in-use standards for SFTP are not needed. As a result, 

CARB expressed an intent to propose aligning the LEV III program with the 

approach EPA proposed on this matter after the Tier 3 program is finalized. The 

manufacturers commented that relaxed interim in-use standards are needed in the 

HDV sector, both for FTP and SFTP standards. The reasons cited were a need to 

harmonize with LEV III, the scarcity of data on which to establish standards that 

apply over the full useful life, the extension of that useful life to 150,000 miles, the 

need for manufacturers to address customer concerns with new products and 

technologies, uncertainties that accompany the new SFTP cycles and Part 1066 

testing requirements (especially for PM), and the introduction of innovative 

technologies required to meet GHG standards in the same timeframe.

After considering the comments we have concluded that relaxed interim inuse standards are appropriate for HDVs, both for FTP and SFTP testing. We are 

adopting HDV in-use standards levels that are identical to those adopted for LEV 

III, as shown in Table IV-13. We consider these levels reasonable, in line with 

relaxed in-use standards adopted in past programs, and helpful toward 

harmonization. We are not applying interim in-use NMOG+NOx standards to the 

interim (two highest) bins for the FTP standards, because these bins are intended for 

carry-over of existing designs, and there should be little uncertainty over their inuse emissions performance. Interim bin vehicles certified to the Tier 3 PM 

standards shall, however, be subject to the relaxed in-use PM standards in the same 

way as for HDVs in other bins. Bin 0 standards are driven by specific zero-
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emissions technologies for which in-use margins would not be appropriate, and so 

we are not setting in-use standards for Bin 0.

We are also adopting the general approach taken in LEV III of making these 

interim standards available during the phase-in period (model years 2016-2022) for 

the first two model years that a test group is newly certified to a Tier 3 

NMOG+NOx or PM standard. Test groups subsequently recertified to a more 

stringent NMOG+NOx bin standard may begin the two year cycle over again. A 

test group that is first certified into a Tier 3 bin in model year 2022 or later may not 

take advantage of the relaxed interim in-use standards. LEV III adopted somewhat 

different applicability years, for the most part ending earlier, in model year 2020. 

However, we believe that the modest extension is appropriate to facilitate the Tier 3 

phase-in. If a vehicle test group is certified into a Tier 3 bin, but not yet to the Tier 

3 PM standard, the in-use standard for PM shall apply for the first two model years 

it is first certified to the PM standard. In order to better harmonize with LEV III, 

the availability of these in-use standards includes the voluntary model years.

Table IV-17 Interim In-Use Standards for HDVs

FTP (mg/mi) SFTP (mg/mi)

NMOG+NOX PM NMOG+NOX PM

Class 2b:

Bin 395 (interim) --

a

16 --

a

--

a

Bin 340 (interim) --

a

16 --

a

--

a

Bin 250 370 16 770/1120 b12/15b

Bin 200 300 16 770/1120 b12/15 b

Bin 170 250 16 490/630 b12/15 b

Bin 150 220 16 490/630 b12/15 b

Bin 0 --

a

--

a

--

a

--

a

Class 3:

Bin 630 (interim) --

a

20 --

a

--

a

Bin 570 (interim) --

a

20 --

a

--

a

Bin 400 600 20 770 12

Bin 270 400 20 770 12

Bin 230 340 20 490 12

Bin 200 300 20 490 12

Bin 0 --

a

--

a

--

a

--

a

a No relaxed interim in-use standard. 

b The lower value applies to low power-to-weight vehicles optionally certified using only the 

highway portion of the SFTP US06.
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b. HDV Useful Life

Currently the HDV regulatory useful life, the period of use or time during 

which emissions standards apply, is 120,000 miles or 11 years, whichever occurs 

first (40 CFR 86.1805-4). For Tier 3 vehicle criteria emissions we are extending

the useful life to 150,000 miles or 15 years, whichever occurs first. This change 

better reflects the improvements in vehicle durability and longevity that have 

occurred in the several years since the 120,000 mile useful life was established, and 

maintains consistency with the LEV III MDV program and with our Tier 3 program 

for large LDTs, for which the same useful life period is being adopted.

The new useful life requirement applies to Tier 3 HDVs in all bins except 

those designated as interim bins, consistent with the purpose of the interim bins to 

provide for limited carry-over of pre-Tier 3 vehicle designs during the phase-in 

period. Although the percentage application in each year will therefore depend on 

each manufacturer’s fleet binning strategy, the declining NMOG+NOX fleet 

average standard will ensure a robust phase-in of the new useful life requirement 

over the 2018-2022 model years, such that it is expected to be about 50 percent in 

2018, and necessarily reaches 100 percent by 2022 when the interim bins are no 

longer available. For those manufacturers choosing to certify to the voluntary

standards, the new useful life will apply even earlier, in model year 2016 or 2017. 

For manufacturers choosing the alternative percent-of-sales NMOG+NOX

alternative, the new useful life requirement applies to all HDVs counted toward the 

phase-in requirement, resulting in a generally equivalent useful life phase-in rate to 

that of the LEV III-harmonized alternative. 

See Section IV.F.5 for further discussion of useful life requirements with 

regard to GHG standards. Manufacturers may optionally retain the 120,000 mile/11 

year useful life for PM on interim Tier 3 vehicles that are not phased in to the Tier 3 

PM standards. We received no adverse comments on these useful life provisions.

c. Heavy-Duty Alternative Fuel Vehicles

As in the light-duty program, manufacturers must demonstrate heavy-duty 

flexible fuel vehicle (FFV) and dual-fuel vehicle compliance with both the FTP and 

the SFTP emissions standards when operating on both the conventional petroleumderived fuel and the alternative fuel. Dedicated alternative fuel vehicles must 

demonstrate compliance with both the FTP and SFTP emission standards while 

operating on the alternative fuel. For all of these vehicles, this includes the 

requirement to meet FTP emissions standards when conducting fuel consumption 

and GHG emissions testing, and also to meet the FTP and highway test 

requirements at high altitudes (see Sections IV.B.6.e and f). Because FFVs can 

operate on various combinations of their conventional and alternative fuel, the 

emissions requirements apply to operation at any mix of the fuels achievable in the 

fuel tank with commercially available fuels, including for compliance at high 
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altitudes, even though the required demonstration of compliance is limited to the 

conventional and alternative fuels designated for certification testing. We received 

no adverse comments on these provisions.

d. Existing Provision to Waive HDV PM Testing

EPA’s existing program includes a provision for manufacturers to waive 

measurement of PM emissions in non-diesel heavy-duty vehicle emissions testing. 

As proposed, we are eliminating this provision. We believe that the Tier 3 PM 

standards for these vehicles are of sufficient stringency that routine waiver of 

testing is not appropriate. The CARB LEV III program also reflects this view. We 

do not expect this change to be onerous for manufacturers, as the number of heavyduty vehicle families is not large. We received no adverse comments on this 

change.

e. Meeting HDV Standards in Fuel Consumption and GHG Emissions 

Testing

As with the light-duty Tier 3 program, HDVs must meet the FTP bin 

standards when tested over both the city and highway test cycles. We do not 

believe this adds a very significant test burden as vehicle emissions are already

required to be measured when these tests are run for GHG and fuel consumption 

determinations. Nor do we believe that this requirement is design forcing. Rather, 

we are creating this requirement to ensure that test vehicle calibrations are not set 

by manufacturers to minimize fuel consumption and GHG emissions, at the expense 

of causing high criteria pollutant emissions. Considering the additional work 

involved in measuring PM emissions and the reduced likelihood of high PM 

emissions on the highway test, we are not mandating that PM emissions testing be 

included in this requirement. We received no adverse comments on these proposed 

provisions.

f. HDV Altitude Requirements

As in the past, we intend that HDV Tier 3 standards result in emissions 

controls that are effective over a full range of operating altitudes. We proposed that 

HDVs be required to meet the FTP bin standards (but not the SFTP standards) at 

high altitudes, and expressed our expectation that compliance with the FTP 

standards would require neither the use of special hardware nor adjustment to the 

level of the standards.

The manufacturers argued in their comments that the reasons EPA cited in 

proposing relief at high altitudes for light-duty vehicles apply for HDVs as well, 

and requested that relaxed NMOG+NOx standards be adopted in the more stringent 

bins for testing of HDVs at high altitudes. Ford argued that the challenges could be 

even greater for HDVs because they are designed to operate at high altitudes with 
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heavy payloads and towed trailers, and this may necessitate the locating of 

emissions systems farther from exhaust manifolds, thereby increasing catalyst 

lightoff delays.

Although we agree to a certain extent about the performance of gasolinefueled HDVs at high altitudes and their similarity to LDVs, the comments did not 

alter our view that the compliance margins provided in the HDV FTP bin standards 

compared to what the control technologies can achieve, and the freedom 

manufacturers have to shift to the more stringent bins gradually as the program 

phases in, are adequate to account for these effects at altitude. The manufacturers 

provided no data to counter this view. 

We note that our adoption of relaxed interim in-use standards for vehicles in 

these bins will be directionally helpful to address any remaining concerns by

manufacturers regarding emissions at altitude (Section IV.B.6.a). This is because 

testing at high altitudes is often not required for certification (typically 

manufacturers use an engineering analysis instead), and thus the relaxed in-use 

standards will help to facilitate Tier 3 implementation for any HDV designs in 

which in-use problems at high altitudes surface in the initial model years.

C. Evaporative Emissions Standards

Gasoline vapor emissions from vehicle fuel systems, which are a mixture of 

hydrocarbon compounds, occur when a vehicle is in operation, when it is parked, 

and when it is being refueled. Evaporative emissions which occur daily from 

gasoline-powered vehicles are primarily functions of air and fuel temperature, fuel 

vapor pressure, and vehicle driving. EPA first instituted evaporative emissions 

standards in the early 1970s to address hydrocarbon emissions when vehicles are 

parked after being driven. These are commonly referred to as hot soak and diurnal 

emissions. Over the subsequent years the test procedures have been modified and 

improved, the standards have been revised to be more stringent, and we have 

addressed emissions which arose from new fuel system designs by establishing new 

requirements such as running loss emission standards and test procedure provisions 

which address resting losses (e.g., permeation). Onboard refueling vapor recovery

(ORVR) requirements for control of refueling emissions first began to phase-in for 

light-duty vehicles (LDVs) and light-duty trucks (LDTs) in the 1998 MY. These 

were later expanded to cover medium-duty passenger vehicles (MDPVs) and some 

heavy-duty gasoline vehicles (HDGVs). 

Even though evaporative and refueling emission control systems have been 

in place for most of these vehicles for many years, evaporative emissions still 

contribute 30-40 percent of the on-road mobile source hydrocarbon inventory. The 

rate of these emissions in grams/day (hot soak and diurnal), grams/mile (running 

loss) or grams per gallon (refueling) depends on (1) the stringency of the 
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applicable emission standards, (2) ambient and fuel temperature, (3) fuel vapor 

pressure, and (4) the presence/ state of repair of the fuel/evaporative control system. 

These fuel vapor emissions are ozone and PM precursors, and also contain 

air toxics such as benzene. Even though there are mature evaporative emission 

control programs in place, further hydrocarbon emission reductions are needed and 

can be achieved from further evaporative emission controls on gasoline-powered 

highway motor vehicles. 

This section discusses the vehicle evaporative emission standards and 

related provisions for LDVs, LDTs, MDPVs, and HDGVs. The evaporative 

emissions program has six basic elements: (1) the early allowance program (MY 

2015-2016), (2) the transitional program (MY 2017), (3) the Tier 3 evaporative 

emission phase-in program (MY 2018-2021), (4) the fully phased-in standards 

(MY2022+), (5) requirements for HDGVs including ORVR for the 2018MY, and 

(6) a leak standard and test procedure which become mandatory for Tier 3 vehicles 

in the 2018MY. As discussed below, we are finalizing more stringent standards 

that will apply for the 2- and 3- day evaporative emissions tests, a canister bleed test 

procedure and emission standard, and a new certification test fuel specification.

342

 

As discussed in section IV.D, we are also adding a fuel/vapor system leak standard 

and test procedure for LDVs, LDTs, and MDPVs. EPA is not changing any existing 

light-duty running loss or refueling emission standards with the Tier 3 FRM, with 

the exception of the certification test fuel specification and the addition of a

refueling emission controls for complete HDGVs over 10,000 lbs gross vehicle 

weight rating (GVWR). This section also describes phase-in flexibilities, credit and 

allowance programs, and other issues related to evaporative emissions control. 

In this rule, the vehicle classifications, LDVs, LDTs, MDPVs, and HDGVs, 

remain unchanged from Tier 2 (see 40 CFR 86.1803-010). For purposes of this 

discussion of the Tier 3 evaporative emissions program, the vehicle standards can 

be further placed in four categories: (1) “zero evaporative emission” PZEV vehicles 

certified by CARB as part of the ZEV program, (2) vehicles certified by CARB to 

meet LEV III evaporative emission program requirements on CARB certification 

fuel (7 RVP E10) as early as 2014 MY, (3) vehicles meeting the Tier 3 evaporative 

emissions program requirements using the Tier 3 certification test fuel (9 RVP 

E10), and (4) transitional vehicles meeting existing EPA evaporative requirements 

on Tier 2 certification test fuel (9 RVP E0).343,344 For ease of reference these four 

 

342 Certification fuel provisions for evaporative and refueling emissions testing for flexible fuel 

vehicles (FFVs) are discussed separately below.

343 We adopted the most recent vehicle evaporative emission standards for LDVs, LDTs, and 

MDPVs in 2007 (72 FR 8428, February 26, 2007). The most recent standards for HDGVs were 

adopted in 2000 (66 FR 5165, January 18, 2001). 
Page 197 of 529

categories may be referred to as PZEV evap, LEV III evap, Tier 3 evap, and Tier

2/MSAT evap in this section.345

1. Tier 3 Evaporative Emission Standards 

a. Final Standards

The Tier 3 program for evaporative emissions builds on previous EPA 

requirements as well as the evaporative emissions portion of CARB’s recent LEV 

III rule which starts mandatory phase-in with the 2018 MY. The level of the 

standards, the timing of their implementation, and related provisions are designed in 

great measure to allow manufacturers to design, certify, and build one control 

system for each evaporative/refueling family to meet CARB and EPA requirements 

so that these vehicles can be sold in all 50 states. Commenters supported this 

approach and no commenter opposed the stringency or timing of the evaporative 

emission standards and related test procedures. We believe the program is 

appropriate since it will require new more stringent evaporative emissions control 

technology in new vehicles and also achieve improved in-use system performance. 

Section IV.C.1.a.i, which follows, describes the basic emission standard 

levels for LDVs, LDTs, MDPVs, and HDGVs. Section IV.C.1.a.ii, describes a new 

canister bleed standard and testing requirement for measuring emissions from the 

evaporative canister. Section IV.C.1.a.iii discusses the optional use of the CARB 

LEV III Option 1 evaporative emission standards during a transition period. Next, 

Section IV.C.1.a.iv discusses interim use of CARB PZEV zero evap data based on 

CARB Phase II fuel. Finally section IV.C.1.a.iv, discusses the ongoing requirement 

to meet running loss emission standards.

 

344 See Section IV.F for a discussion of the final certification fuel provisions, including discussion of 

options for and implications of the certification test fuel having 10 percent ethanol.

345

 “PZEV evap” as discussed here refers only to the evaporative emission and useful life 

requirements of the PZEV program, not the exhaust emission requirements.
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i. Hot Soak Plus Diurnal Standards

 The Tier 3 hot soak plus diurnal emission standards are designed to bring 

into the broader motor vehicle fleet the “zero evap” technology used by the 

manufacturers in their partial zero emission vehicles (PZEVs). Manufacturers 

developed this “zero evap” technology as part of their response to meeting the 

requirements of the CARB Zero Emission Vehicle (ZEV) program. This program, 

which is in effect in 11 other states, allows manufacturers to meet their ZEV 

mandate percentages (totally or in-part) by the use of vehicles which among other 

characteristics have very low fuel vapor emissions. 

The hot soak plus diurnal emission standards we are adopting (presented in 

Table IV-18) are designed to be met with technology that limits Tier 3 vehicles to

essentially zero fuel vapor emissions. For the Tier 3 evaporative emissions 

program, we are not changing the basic 2-and 3-day evaporative emission test 

procedures other than the certification fuel requirements. The level of the 

standards primarily accommodates what is often referred to as new vehicle 

background hydrocarbon emissions. These emissions arise from the off-gassing of 

volatile hydrocarbons from plastics, rubbers, and other polymers found in new 

vehicles (e.g., new tires, interiors, seats, fuel system components, paints, and 

adhesives). In the field these emissions decrease over time as the vehicle ages, but 

this cannot necessarily be replicated in the time that manufacturers typically

allocate for vehicle certification or with the techniques normally used for vehicle 

pre-conditioning. Provisions related to vehicle pre-conditioning before evaporative 

emissions certification testing are discussed further below.

In the past EPA has set relatively uniform (but not identical) evaporative 

emission standards for LDVs and LDTs and somewhat higher values for MDPVs 

and HDGVs. The Tier 3 hot soak plus diurnal emission standards follow this 

approach, because in general the vehicles have higher levels of non-fuel 

background emissions as they get larger. 

 As described in more detail in Section IV.C.2.d below, EPA is finalizing a 

program that will allow manufacturers to demonstrate compliance with the hot soak 

plus diurnal evaporative emission standards using averaging concepts. A 

manufacturer may comply by averaging within each of the four vehicle categories 

but for the reasons discussed below, may not rely on averaging across categories. 

The technical approaches to meeting the standards are discussed in Section IV.C.2. 

Table IV-18 Final Evaporative Emission Standards (g/test)a,b,c

Vehicle Category/Averaging Sets Highest Hot Soak + Diurnal Level

(over both 2-day and 3-day diurnal 

tests)

LDV, LDT1 0.300
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LDT2 0.400

LDT3, LDT4, MDPV 0.500

HDGVs 0.600

a The standards are in grams of hydrocarbons as measured by flame ionization detector during the 

diurnal and hot soak emission tests in the enclosure known as the sealed housing for evaporative 

determination (SHED).

b Note that the standards are the same for both tests; existing current standards are slightly different 

for the 2- and 3-day tests.

c Vehicle categories are the same as in EPA’s Tier 2 final rule; see 65 FR 6698, February 10, 2000. 

ii. Canister Bleed Emission Standard

In addition to more stringent hot soak plus diurnal standards, EPA is 

finalizing a new canister bleed emission test procedure and standard as part of the 

Tier 3 program. The canister bleed test procedure is described in Section IV.C.6

below. EPA is adopting the canister bleed standard because it is an important tool 

in moving Tier 3 evaporative emissions control toward zero fuel vapor emissions. 

No commenter opposed the canister bleed standard or commented on the test 

procedure. The new test and standard align with the California LEV III 

requirements and help to ensure that near-zero fuel vapor emissions are being 

emitted by vehicles from the fuel tank through the evaporative emission canister. 

Manufacturers will be required to measure diurnal emissions over the 2-day diurnal 

test procedure from just the fuel tank and the evaporative emission canister using 

Tier 3 certification fuel and comply with a 0.020 g/test standard for all LDVs, 

LDTs, and MDPVs and 0.030 g/test for HDGVs. The feasibility of this standard is 

discussed in Section IV.C.3 below. The canister bleed test and standard drives 

canister design elements such as total gasoline working capacity, internal 

architecture, and the type of carbon used. These are also key elements of canister 

design for the hot soak plus diurnal emission standards. 

The canister bleed standard will be implemented differently than the hot 

soak plus diurnal standard. EPA is not applying the averaging program to this new 

bleed test standard as compliance is relatively straightforward and low in cost. 

Therefore, each evaporative/refueling emission family certified by manufacturers 

will need to demonstrate compliance with their respective standard. As discussed 

below, the canister bleed standard will not apply at high altitude, but proportional 

control is expected. Since the performance of the canister is also evaluated in the 

hot soak plus diurnal evaporative emissions sealed housing for evaporative 

determination (SHED) test the canister bleed emission standard will not be included 

in the In-Use Verification Program of under 40 CFR 86.1845 through 1853, but it 

must be met in use. We will not have canister bleed specific family criteria for 

certification but the test will have to be completed and the standard met for each 

evaporative/refueling family including potentially twice if there are two canisters 

used. A deterioration factor will not be required, but the manufacturer must certify

that the standard will be met for the full useful life. As mentioned above, the 
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standard will have to be met in-use and could be evaluated in EPA confirmatory

testing.

The canister bleed standard will have to be met using the same fuels and test 

procedures used for the hot soak plus diurnal standards. We will accept results on 

either CARB or EPA test fuels/test temperatures for the canister bleed test provided 

the same are used for the hot soak plus diurnal test. 

iii. Hot Soak Plus Diurnal Standard with the Fuel System Rig Test 

As part of its LEV III program, CARB has included an alternative set of 

evaporative emission standards, referred to as Option 1 standards. These are shown 

in Table IV-19.

Table IV-19 CARB Option 1 Evaporative Emission Standards

Vehicle Category

Highest Hot Soak + 

Diurnal Level (over both 2-

and 3-day diurnal tests) 

(g/test)

Running Loss

(g/mile)

Vehicle 

SHED

Rig

SHED

Passenger Car 0.350 0.0 0.05

LDT < 6,000 lbs GVWR 0.500 0.0 0.05

All other vehicles > 6,000 

lbs GVWR 0.750 0.0 0.05

The Option 1 standards include evaporative emission standards (hot soak 

plus diurnal) that are slightly higher numerically than our final standards. Vehicles 

certified under this option may not use averaging in the CARB LEV III program 

because they basically represent the same evaporative emission standards as exist 

for PZEVs under CARBs ZEV program wherein averaging is not permitted. Option 

1 also includes an additional SHED test of the vehicle fuel system (rig test) that predates development of the canister bleed emission standard. The rig SHED test is 

discussed in Section IV.C.6. From a practical perspective, this test is more difficult 

to conduct than the bleed test discussed above and is intended to force 

manufacturers to demonstrate at certification that their stand alone (not in chassis) 

fuel/vapor control system designs have < 54 mg fuel vapor emissions.346 While one 

commenter was in favor of permanently including Option 1 in the EPA final rule 

 

346 Any value < 54mg rounds down to zero under the regulations.
Page 201 of 529

based on what it viewed to be favorable pre-production engineering design features 

of the rig SHED test, EPA is including Option 1 only as interim compliance 

alternative for a limited period of time but not as a permanent option in the Tier 3 

evaporative emission program. While we see the value to vehicle manufacturers of 

the rig SHED test as an engineering design and development tool, by its very

nature, the rig SHED test and standard is not implementable as an enforceable 

standard because a fuel system cannot be removed from a vehicle and reconstructed 

in a SHED for testing without compromising its fundamental structural and 

mechanical integrity as it existed on the vehicle. We believe that the hot soak plus 

diurnal SHED test and standard and the canister bleed test and standard will 

accomplish the objective of keeping fuel vapor emissions to a minimum while 

doing so in an enforceable manner. 

EPA believes most manufacturers will prefer to certify to the averaging 

based standards in Table IV-1 (similar in stringency and program construct to 

CARB Option 2). However, because some manufacturers may have vehicle models 

meeting the CARB Option 1 standards and emission requirements now or in the 

near future, EPA will allow compliance with the CARB Option 1 standards as an 

acceptable interim alternative to compliance with the Tier 3 evaporative emission 

standards if the model is certified by CARB to LEV III requirements before the 

2017 MY. These vehicles could then be certified using carryover provisions 

through the 2021 MY as part of the evaporative emissions phase-in described 

below. This is two model years longer than in the proposal, but this extension is 

reasonable given the life cycle of most fuel/vapor control systems and the goal of 

aligning with the LEV III program for a national program where possible.347 As 

noted in the following sections, vehicles certified under this provision will count 

toward the phase-in percentage requirements and could earn allowances as 

discussed below, but the vehicles will not be eligible to earn or use credits for the 

evaporative emissions averaging program. Carryover vehicles will have to meet the 

EPA leak standard and the high altitude emission standard to be counted toward the 

sales percentage requirements for 2018 and later model years.

iv. Interim Carryover of PZEV Evap Data for Tier 3 Certification

To earn credits toward compliance with the CARB Zero Evaporative 

Emissions (ZEV) program requirements, many manufacturers have certified LDVs 

and LDTs to 150,000 mile useful life emission standards similar to those found in 

Table IV-19. These vehicles have used CARB Phase II fuel (E0) and met the rig 

SHED test requirement in lieu of the canister bleed standard, but otherwise have 

employed the same basic technology EPA expects for the LEV III and Tier 3 

 

347 EPA is incorporating by reference the CARB Option 1 test procedures and emission standards for 

this interim period. 
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programs. EPA is permitting data generated from certification of these vehicles in 

the 2015 and 2016 MYs to be used for Tier 3 evaporative emissions purposes 

through the 2021 MY.

v. Running Loss Emission Standards

EPA has required vehicles to meet running loss emission standards since the 

1996 model year. These requirements, which are specified in 40 CFR §86.134-96, 

apply to all gasoline-powered highway motor vehicles. EPA is not changing either 

the test procedures or emission standard for the running loss test. However, the 

change in certification test fuel will apply to testing for such standards. This is 

appropriate based on the rationale for implementing a certification fuel change and 

is necessary since the running loss test is part of the overall test sequence for the 3-

day hot soak plus diurnal test. EPA does not anticipate that the change in 

certification test fuel will impact the stringency of the running loss test and 

standards or the manufacturers’ ability to comply as part of Tier 3.

b. High-Altitude Requirements

Prior to this rule, the most recent vehicle evaporative emission standards 

were adopted in 2007.348 The new standards adopted in 2007 apply only to testing 

under low-altitude conditions.349 In the 2007 rule, we decided to continue to apply

the previous “Tier 2” standards for testing under high-altitude conditions. This was 

necessary to achieve an equivalent level of overall stringency for high-altitude 

testing, accounting for the various effects of altitude and lower atmospheric 

pressure on vapor generation rates, canister loading and purging dynamics, and 

other aspects of controlling evaporative emissions due primarily to lower air density

and vapor concentrations at altitude. While it is important for vehicles to have 

effective emission controls at high altitudes, we do not want the high-altitude 

standards and test procedures to dictate the fundamental design of the Tier 3 

evaporative emission control systems since the high altitude vehicle population is 

only about five percent of the national total. Therefore, we believe it is appropriate 

to address this goal by applying the current 2-day low altitude evaporative emission 

standards and requirements for high-altitude testing.350 The vehicle categories for 

the high altitude standards in this rule are the same as for the low altitude standards. 

 

348 See 72 FR 8428 (February 26, 2007).

349 Low altitude conditions means a test altitude less than 549 meters (1,800 feet). High-altitude 

conditions means a test altitude of 1,620 meters (5,315 feet) plus or minus 100 meters (328 feet) or 

equivalent observed barometric test conditions of 83.3 kPa (24.2 inches Hg) plus or minus 1kPA 

(0.30 inches Hg) See 40 CFR 86.1803-01.. 

350 See Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle 

Standards and Highway Diesel Fuel Sulfur Control Requirements 66 FR 5002, January 18, 2001and 

Control of Hazardous Air Pollutants from Mobile Sources, 72 FR 8428, February 26, 2007.
Page 203 of 529

The standards are presented below in Table IV-20. This will both reduce 

evaporative emissions at high altitude and again create a requirement to confirm 

that emission controls function effectively at high altitude without forcing 

manufacturers to apply altitude-specific technologies. The leak standard presented 

in Section IV.D below will apply equally at low and high altitude testing as 

compliance is not dependent on air density and vapor concentrations.

Table IV-20 Final High-Altitude Evaporative Emission Standards (g/test)

Vehicle Category Highest Hot Soak + Diurnal Level

(over both 2-day and 3-day tests)(g/test)

LDV, LDT1 0.65

LDT2 0.85

LDT3, LDT4 1.15

MDPV 1.25

HDGVs < 14,000 lbs GVWR 1.75

HDGVs > 14,000 lbs GVWR 2.3

A few additional points should be noted about our Tier 3 high altitude 

evaporative emissions control program. First, EPA does not expect manufacturers 

to produce vehicles with high-altitude only evaporative control systems. Given the 

nature of evaporative emission control technology, there should be emission 

reductions at high altitude proportional to those achieved at lower altitudes. We are 

not applying the canister bleed test and emission standard at high altitude, but we 

expect similar emission reductions to those which will occur at low altitude. These 

vehicles will have to meet the canister bleed emission standard at low altitude and 

canister bleed emission reductions at high altitude should be proportional as is the 

case with the low altitude hot soak plus diurnal standards. Any adjustment to meet 

the standard at high altitude to account for canister adsorption and desorption 

effects of higher altitudes would result in fundamentally the same technology with 

an increase in the testing burden but not necessarily more emissions control. 

Therefore, we believe the low-altitude canister bleed test is sufficient for achieving 

the level of emission control for operation in both low-altitude and high-altitude 

conditions. Second, for vehicles certified with FELs above or below the applicable 

standard for testing at low altitude, the same differential will apply to the FELs for 

high-altitude. For example, if an LDV was certified with an FEL of 0.400 g instead 

of the 0.300 g standard, the high-altitude FEL will be 0.75 g (0.65g+0.10g). This 

high-altitude FEL will not be used for any emission-credit calculations, but it will

be used as the emission standard for compliance purposes. Third, gasoline RVP for 

certification test fuel will be set at 7.8 RVP with 10 percent ethanol, as specified in 

Section IV.F. Finally, we are finalizing a minor adjustment to the high altitude test 

procedures. The existing 2- and 3-day test procedures apply equally at low and high 
Page 204 of 529

altitude. We are keeping the same basic requirement but will allow for a downward

adjustment of 5 °F in the temperatures related to the running loss test within the 3-

day test cycle. Thus, the applicable ambient temperatures at §86.134-96 (f) and (g) 

will be 90±5 °F instead of 95±5 °F for high altitude testing, and the entire fuel 

temperature profile from §86.129-94(d) shifts down by 5°F. EPA believes this is 

appropriate given the differences in atmospheric conditions at low versus high 

altitude and will still result in equivalent control of running loss emissions at higher 

altitudes. EPA requested comment on the alternative approach of keeping test 

temperatures the same, but omitting the 3-day test cycle for testing at high altitude. 

This was supported by one set of commenters, but at this time EPA does not have 

the data needed to drop such a fundamental test requirement.

As mentioned above, emission data from vehicles meeting the current 

CARB PZEV zero evap and CARB LEV III Option 1 requirements could be used to 

qualify that vehicle to meet the Tier 3 evaporative emission regulations for the 

2017-2021 MYs. To qualify for a federal certificate, the vehicle will also have to 

meet the Tier 3 high altitude evaporative emission requirements. CARB does not 

require vehicles to meet EPA high altitude requirements, so for these vehicles we 

are giving the manufacturers the option to certify either by providing SHED test 

data or based on an engineering demonstration using data and analysis and the 

application of good engineering judgment. For the 2015-2017MYs, manufacturers 

can use data based on either Tier 2 or Tier 3 test fuel. Beginning in the 2018 model 

year, for Tier 3 vehicle certification to the high altitude standard, the data must be 

based on Tier 3 fuel. 

c. Useful Life 

Trends indicate that vehicle lifetimes are increasing. It is important that 

emission control systems be designed to meet requirements while vehicles are in 

use. As discussed in Section IV.A.7 and IV.B.6 of this preamble, along with the 

new emission standards, we are finalizing a longer useful life of 150,000 miles/15 

years, whichever comes first, for LDTs up to 6,000 lbs GVWR but over 3,750 lbs 

loaded vehicle weight (LVW) (LDT2s), all LDTs over 6,000 lbs GVWR (LDT3/4), 

MDPVs, and HDGVs. The longer useful life will apply to all certifications to the 

Tier 3 evaporative emission standards (see Table IV-18 and Table IV-19 above). 

For an evaporative/ refueling family certified to 150,000 miles/15 year useful life 

for evaporative emissions this useful life will also apply to the hot soak plus diurnal, 

running loss, canister bleed, fuel system rig, refueling, leak, and high altitude 

standards. All of these standards impact the fuel and vapor control systems and it is 

technologically consistent to require the same useful life for these standards because 

they all rely on the mechanical integrity, durability, and operational performance of 

the same components in the evaporative emissions control system. 

Due to limitations in the CAA, for LDVs and for LDTs up to 6,000 lbs 

GVWR and at or below 3,750 lbs LVW (LDT1s), we are keeping the current useful 
Page 205 of 529

life of 120,000 miles/10 years unless, as described in Section IV.A.7, a 

manufacturer elects alternative exhaust emission requirements that are associated 

with 150,000 mile/15 year useful life for these vehicles. For manufacturers that 

select those optional standards, the useful life of 150,000 miles/15 years will apply

for all Tier 3 evaporative emission requirements as listed in the previous paragraph. 

During the early, transition, and phase-in program periods and until the final 

year of the allowed phase-in period for the Tier 3 evaporative emission program 

(MY 2015-2021) the differences between the exhaust and evaporative emission 

phase-in programs presents the possibility that in some cases a manufacturer could 

certify a model to the Tier 3 exhaust requirements (or CARB equivalents) but not 

necessarily to the Tier 3 evaporative emission requirements.351 In those situations, 

the final rule provides that a family could have a 150,000 miles/15 years useful life 

for exhaust emissions but maintain the current useful life for all of the evaporative 

and refueling emission standards since the vehicle does not yet meet Tier 3 

evaporative emission requirements. During the phase-in period, if a family is 

certified to the Tier 3 evaporative emission requirements but not yet certified for 

Tier 3 exhaust emission requirements, then the useful life could be 150,000 

miles/15 years for evaporative and refueling emissions standards but the existing

useful life for exhaust emissions. However, by the 2022 MY the useful life for all 

of these requirements will be 150,000 miles/15 years for LDT2/3/4s, MDPVs, and 

HDGVs since by that model year all vehicles must be certified using Tier 3 

certification fuel and test procedures and meet Tier 3 evaporative emission 

standards or CARB equivalents.

352

OBD regulations call for the systems to operate effectively over the useful 

life of the vehicle. We are not changing that requirement, but rather want to clarify

that during the early, transition, and phase-in years of the program (MY 2015-

2021), all of the OBD monitoring requirements have the same useful life as that for 

the exhaust emission standard except for the evaporative system leak monitoring 

requirement which has the same as that required for the evaporative and refueling 

emission standards control systems.

 

351 By the 2022 MY, all Tier 3 evaporative system emissions certifications must use Tier 3 

certification test fuel and test procedures or equivalent CARB test procedures, certification and 

emission standards. This affects evaporative (hot soak plus diurnal), running loss, and canister bleed

emission standards certification. Refueling, spit back and leak standards are only to be met using 

Federal certification test fuel.

352 The only exception here will be for vehicles not meeting Tier 3 evaporative emission 

requirements in the 2022 MY as a result of the use of previously earned allowances.
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d. What Requirements Must a Vehicle Meet to Qualify as a Tier 3 Vehicle 

for Evaporative Emissions?

As mentioned above, there are three different revised or new evaporative 

emision requirements applicable to Tier 3 vehicles. These are the hot soak plus 

diurnal standards, the canister bleed standard, and the leak standard. In addition the 

refueling, running loss, and spit back standards are unchanged but will have to be 

met on Tier 3 certification fuel. Compliance with these requirements is potentially

complicated by the fact that the CARB ZEV and LEVIII programs will bring zero 

evap technology into the market place before or at the same time that Tier 3 

implementation begins but with test fuel and test procedure differences. In order to 

qualify as a Tier 3 vehicle for evaporative emission purposes the vehicle must meet 

all applicable requirements on the specified fuel. Unless otherwise specified (e.g., 

HDGV refueling spit back), if a vehicle does not meet all evaporative emission 

program requirements, including both the applicable standards and test fuel then it 

does not qualify as a Tier 3 vehicle for evaporative emission purposes. Table IV-4, 

below summarizes the requirements that vehicles in various categories must meet to 

qualify as a Tier 3 vehicle for evaporative emission purposes as a function of model 

year. The entries in the cells of the table specify the required test fuel. The table is 

for reference of the reader in reviewing subsequent sections of this preamble. Refer 

to the regulatory text for specific requirements for the various programs.

Table IV-21 Requirements for Vehicle to Qualify for Tier 3 Evaporative 

Emissions Program and Test Fuel Requirements

Model 

Year

Program/ 

Zero Evap 

Stds

HS+DI/

Running 

Loss

Rig Canister

Bleed

Leak 

(except 

HHDGV)*

High 

Altitude & 

Refueling/

Spit back **

 MY 2017 TRANSITION PROGRAM

2017 Percentage

- PZEV 

zero evap

(carryover)

CA Ph. 2 CA 

Ph. 

2

N/A N/A EPA Tier 2

or Tier 3 

2017 Percentage 

- LEV III 

Opt. 1

CA Ph. 3 CA 

Ph. 

3

N/A N/A EPA Tier 3 

2017 Percentage 

- LEV III 

Opt.2 

CA Ph. 3 N/A CA Ph. 

3

N/A EPA Tier 3

2017 Percentage 

- Tier 3

Tier 3 N/A EPA 

Tier 3

N/A EPA Tier 3

2017 PZEV zero 

evap only 

CA Ph. 2 CA 

Ph. 

N/A N/A EPA Tier 2

or / Tier 3
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(carryover) 2

2017 20/20-

PZEV 

evap

(carryover)

CA Ph. 2 CA 

Ph. 

2

N/A EPA Tier 

3

EPA Tier 2

or / Tier 3 

2017 20/20-

LEV III 

Opt. 1 

CA Ph. 3 CA 

Ph. 

3

N/A EPA Tier 

3

EPA Tier 3

2017 20/20 -

LEV III 

Opt. 2

CA Ph. 3 N/A CA Ph. 

3

EPA Tier 

3

EPA Tier 3

2017 20/20 -

Tier 3

Tier 3 N/A EPA 

Tier 3

EPA Tier 

3

EPA Tier 3

 MY 2018-2021 PHASE-IN PROGRAM

2018-

2019

PZEV zero 

evap 

(carryover)

CA Ph. 2 CA 

Ph. 

2

N/A EPA Tier 

2 or Tier 3

EPA Tier 2

or Tier 3 

2018-

2021

LEVIII 

Opt.1

CA Ph. 3 CA 

Ph. 

3

N/A EPA Tier 

3

EPA Tier 3

2018-

2021

LEVIII 

Opt. 2

CA Ph. 3 N/A CA Ph. 

3

EPA Tier 

3

EPA Tier 3

2018-

2021

Tier 3 Tier 3 N/A EPA 

Tier 3

EPA Tier 

3

EPA Tier 3

 MY 2022+ FULLY PHASED-IN PROGRAM

2022+ LEV III 

Opt. 2

CA Ph. 3 N/A CA Ph. 

3

EPA Tier 

3

EPA Tier 3

2022+ Tier 3 Tier 3 N/A EPA 

Tier 3

EPA Tier 

3

EPA Tier 3

* LHDGVs are heavy-duty gasoline vehicles with a GVWR equal to or less than 14,000 lbs; 

HHDGVs are heavy-duty gasoline vehicles with a GVWR in excess of 14,000 lbs.

** Incomplete HDGVs without ORVR may defer demonstrating compliance with the spit back 

requirement on Tier 3 fuel until the 2022 MY.

2. Program Structure and Implementation Flexibilities 

a. Percentage Phase-In Requirements

As proposed, the final Tier 3 evaporative emission standards will be phased 

in over a period of six MYs 2017-2022. Manufacturers supported the proposed 

phase-in schedule and there were no issues raised with regard to lead time for any

vehicle class. As discussed below, there will be three options for the 2017 MY. 

For the 2018-2019 MYs, the requirement will apply to 60 percent of a 
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manufacturer’s nationwide sales of all LDVs, LDTs, MDPVs, and HDGVs

(including vehicles sold in California and the section 177 states). This will increase 

to 80 percent for MYs 2020 and 2021 and by MY 2022 it will apply to 100 percent 

of sales in these four categories. Beginning in MY 2018 any vehicle included in the 

percentage phase-in, except vehicles that had earned allowances, will have to meet 

the leak standard discussed in section IV.D.

 Evaporative emission requirements for the MY 2017 apply only to LDVs, 

LDT1s, and LDT2s as defined in 40 CFR §86.1803-01. To be consistent with the 

start date for Tier 3 exhaust standards, phase-in requirements will not include 

vehicles over 6,000 lbs GVWR until the 2018 MY. The manufacturers will have 

three options. The first, which we are calling the “primary” or “percentage” option, 

requires that a value equal to 40 percent of a manufacturer’ s LDVs, LDT1s, and 

LDT2s sold outside of California and the states that have adopted the CARB ZEV 

or LEV III programs must meet the Tier 3 evaporative emission requirements on 

average. The 40 percent is calculated based on vehicles at or below 6,000 lbs 

GVWR but compliance can be based on vehicles regardless of their GVWR. The 

second which we are calling the “PZEV zero evap only” option, requires a 

manufacturer to sell all of the LDVs, LDT1s, and LDT2s certified with CARB as 

meeting the PZEV evaporative emission requirements (zero evap) in MY 2017 

throughout all of the U.S. and not to offer for sale any non-PZEV zero evap version 

of those specific vehicle models/ configurations in any state whose vehicles are 

covered by the Tier 3 evaporative emission standards. Thus, this will apply to sales 

in any state except for California and states that have adopted the CARB ZEV or 

LEV III programs under section 177 of the Clean Air Act. Under this second 

option, no tracking of sales or end of year compliance calculation will be required. 

Some manufacturers may find this option attractive, as they have more limited 

product offerings and find tracking of production and sales more difficult. The 

third option, which we are terming the 20/20 option, requires that 20 percent of a 

manufacturer’s LDVs, LDT1s, and LDT2s (e.g., equal to or less than 6,000 lbs 

GVWR) sold outside of California and the states that have adopted the CARB ZEV 

or LEV III programs meet the Tier 3 evaporative emission requirements on average

and that this 20 percent or another 20 percent of vehicles in the three groups listed 

above meet the leak standard discussed in section IV.D. Each percentage 

requirement must be met, (i.e., there is no flexibility to permit meeting shortfalls of 

the hot soak plus diurnal or leak standard percentages with higher values from the 

leak standard category). However, as was the case with the 40 percent option above, 

compliance can be based on vehicles regardless of their GVWR. The third option 

was supported by several commenters as a means to address 2017 MY transition 

issues related to phase-out of current products and phase-in of future products. 

EPA believes that for these vehicles the leak standard will provide emission 

reduction benefits comparable in magnitude to the Tier 3 evaporative emission 

standards. Thus, under this approach, the manufacturers’ product transition 

concerns can be addressed while achieving the overall evaporative emission 
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reductions from 2017 MY vehicles. It should be noted that these vehicles must also 

meet the 0.020” evaporative system leak monitoring requirement which also takes 

effect in the 2017 model year.

As discussed below, beginning in the 2018 MY, to be counted toward the 

percentages needed to meet the Tier 3 phase-in percentages (e.g., 60% in 2018 and 

2019 MYs) a Tier 3 compliant vehicle must also meet the leak standard. 

At the time of certification, manufacturers will identify which families will

be included in their Tier 3 evaporative emission percentage calculations (this could 

be families above or below the individual Tier 3 evaporative emission standards for 

the given class of vehicles (Table IV-18) as well as vehicles meeting CARB’s 

PZEV zero evap or LEV III Option 1 standards (Table IV-19) and could also 

include earned allowances as discussed below. The manufacturers will use 

projected sales information for these families plus allowances as desired and 

available, to show how they expect to meet the phase-in percentage requirements

for the model year of interest. At the end of the model year reconciliation the

manufacturers will be expected to show that the percentages were met. If the 

percentages are not met, the manufacturers will either use additional allowances 

and/or bring more vehicle families/vehicles into the calculation until the sales 

percentage is met. This step is being required because the initial demonstration of 

compliance with the fixed percentage at certification is based on projected sales. If 

the manufacturers did not have to demonstrate that the fixed percentages were met, 

the percentage would then be a goal and not a requirement and there would be no 

means to capture the emission reduction shortfalls. This step is unique to the 

evaporative emission program relative to the NMOG+NOx and PM programs 

because the evaporative program involves both fixed percentages and ABT. The 

NMOG+NOx program involves ABT but does not involve fixed percentages and 

the PM program involves fixed percentages but does not involve ABT. 

 The additional vehicles added to meet the percentage could only be 

meeting the Tier 2 hot soak plus diurnal requirements. In this case, use the larger of 

the 2- or 3- day hot soak plus diurnal certification emission levels. Adding these 

vehicle families/vehicles into the calculations (discussed below) may result in a 

credit deficit for that model year for a given averaging set. A manufacturer could 

not have an unresolved deficit for more than three consecutive model years as 

discussed below. The deficit would have to be eliminated with positive credits not 

later than the ABT calculation and credit reconciliation which occurs after the 

fourth model year. 

As discussed above for exhaust emissions, while unlikely, it is possible that 

a manufacturer could in its annual certification preview meeting with EPA, indicate 

that its technology mix is such that it will have a credit deficit when the sales 

percentages requirement is met. This could occur if the fleet average evaporative 

emission value for Tier 3 vehicles did not meet the Tier 3 hot soak plus diurnal 
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standard for the Tier 3 vehicles in any given averaging set. Also, a manufacturer 

could have a deficit from a previous model. In these situations, certifying with a 

projected or actual deficit would require EPA approval after submission of a plan 

from the manufacturer which explains how it will eliminate the deficit within the 

model years permitted. Even if a manufacturer had projected or actual deficits for 

two or three consecutive model years, all accrued deficits would have to be 

eliminated by the reconciliation which occurs after the fourth model year. Within 

this plan, which would have to be submitted and approved at each annual 

certification preview meeting, EPA would expect to see progress toward 

compliance as indicated by such factors as improved emissions performance for 

future test groups, a substantiated trend toward a more favorable fleet technology

sales mix, no backsliding in projected fleet average values, and perhaps other 

situation specific criteria. 

Requiring a showing at the time of certification based on projected sales 

requires due diligence by the manufacturers and EPA, but the Tier 3 evaporative 

emissions program allows for fleet averaging, so a validation or “truing up” of these 

sales projections after the end of the model year is necessary for determining 

compliance with the requirements of the standard. This is discussed in Section 

IV.C.2.d.iii. As discussed further below, validated sales information will also be 

used for earning early allowances and to show compliance with the alternative 

phase-in schedule approach. 

For these purposes, vehicles included in the phase-in percentage could be: 

(1) families which certified to PZEV zero evap or CARB LEV III Option 1 

requirements in MYs 2015 and 2016, (2) families certified to meet Tier 3 

evaporative emission requirements, (3) any vehicle family certified to the CARB 

LEV III Option 2 hot soak plus diurnal evaporative emission standards, and (4) 

vehicles from the early allowance program. To qualify as a Tier 3 certification for 

evaporative emission purposes, any new evaporative/refueling emission family

certifications will have to meet the EPA Tier 3 certification requirements for both 

test procedure and certification test fuel for the evaporative (hot soak plus diurnal 

and canister bleed, running loss), refueling, and spit back emission standards. The 

leak standard will apply in the 2018 and later MYs to all Tier 3 vehicles except 

HHDGVs and those from the early allowance program. Furthermore, assuming the 

EPA provisions related to carryover of emissions data are met, 2015-2016 MY 

CARB PZEV zero evap evaporative emissions certifications could be carried over 

until the end of the 2019 MY and included as compliant vehicles within the Tier 3 

program if they meet the other applicable Tier 3 requirements. The same is true for 

CARB LEVIII Option 1 certification, except carryover would be permitted through 

the 2021 MY if they meet the other Tier 3 requirements. See Table IV-4for more 

detail on the program options and fuel requirements by model year. 

The phase-in percentages for MYs 2017 through 2022 reflect a percentage 

phase-in concept applied successfully by EPA in previous rules involving 
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evaporative and refueling emissions control. The phase-in provides an appropriate 

balance between the needed emission reductions and time for the manufacturers to 

make an orderly transition to the new technology on such a broad scale. The higher 

initial percentage here is appropriate because the expected evaporative emission 

control technology is already being used to varying degrees by 12 manufacturers on 

over 50 vehicle models today and is projected to gain even deeper penetration by

2017 due to the partial zero emission vehicles (PZEV) option within the CARB 

ZEV program.353

b. Alternative Phase-in Percentage Scheme

As program flexibility, we are allowing manufacturers to demonstrate 

compliance with the phase-in percentage requirements of the evaporative emissions 

program by using a manufacturer-determined alternative phase-in percentage 

scheme. The alternative phase-in percentage provisions allow manufacturers to use 

a phase- in more consistent with product plans such as beginning with a lower 

percentage(s) than required under the primary phase-in during the early years or to 

benefit from producing and selling more than the minimum percentage of compliant 

vehicles early. This flexibility could also be helpful in the event that a 

manufacturer elects to put some vehicles on different phase-in schedules for 

meeting Tier 3 exhaust and evaporative emission standards. As explained further 

below, with some limitations, allowances could be used toward compliance with the 

alternative phase-in scheme values for any given model year.

This approach, which was widely supported in comments by the 

manufacturers, would be available beginning in the 2017 MY for all manufacturers, 

except for any manufacturer which used the “PZEV zero evap only” nationwide 

option for the 2017 MY for whom the approach would be available beginning in 

2018 MY. Vehicle and fuel eligibility requirements for the program are summarized 

in Table IV-22. Refer to the regulatory text for specific requirements.

Table IV-22 Vehicle Qualifications for 2017-2022MY Alternative Phase-in

Percentage Schemes & Test Fuel Requirements

Model 

Year

Program 

Zero Evap 

Stds.

HS+DI / 

Running 

Loss

Rig Canister 

Bleed

Leak 

(except 

HHDGV)*

High 

Altitude & 

Refueling/

Spit back**

2017 PZEV evap

(carryover)

CA Ph. 2 CA 

Ph. 2

N/A N/A EPA Tier 2 

or Tier 3 

2017 LEV III CA Ph. 3 CA N/A N/A EPA Tier 3

 

353See http://driveclean.ca.gov/searchresults_by_smog.php?smog_slider_value=9&x=12&y=12,(last 

accessed on December 6, 2013).
Page 212 of 529

Opt. 1 Ph. 3

2017 LEV III 

Opt. 2

CA Ph. 3 N/A CA Ph. 

3

N/A EPA Tier 3

2017 Tier 3 Tier 3 N/A EPA 

Tier 3

N/A EPA Tier 3

2018-

2019

PZEV evap

(carryover)

CA Ph. 2 CA 

Ph. 2

N/A EPA Tier 2 

or Tier 3

EPA Tier 2 

or Tier 3 

2018-

2021

LEV III 

Opt. 1

CA Ph. 3 CA 

Ph. 3

N/A EPA Tier 3 EPA Tier 3

2018-

2022

LEV III 

Opt. 2

CA Ph. 3 N/A CA Ph. 

3

EPA Tier 3 EPA Tier 3

2018-

2022

Tier 3 Tier 3 N/A EPA 

Tier 3

EPA Tier 3 EPA Tier 3

* LHDGVs are heavy-duty gasoline vehicles with a GVWR equal to or less than 14,000 lbs; 

HHDGVs are heavy-duty gasoline vehicles with a GVWR in excess of 14,000 lbs.

** Incomplete HDGVs without ORVR may defer demonstrating compliance with the spit back 

requirement on Tier 3 fuel until the 2022 MY.

Under this approach, before the 2017 MY (2018MY for a manufacturer 

which used the “PZEV zero evap only” nationwide option for the 2017 MY), a 

manufacturer will present a plan to EPA which demonstrates that the sum of the 

products of a weighting factor and the percentages of their U.S. vehicle sales for 

each model year from 2017 (2018) through 2022 is greater than or equal to 1280 if 

the program started in the 2017 MY (or 1040 if the program started in the 2018 

MY). The 1280 and 1040 numerical values are equal to the sum of the product of 

the weighting factors and the percentage requirements for MY 2017 or 2018 start 

dates, respectively, as applicable through MY 2022. These are calculated in the 

following manner: [(6)(2017MY%)+(5)(2018MY%) +4(2019MY%)+

3(2020MY%) +2(2021MY%) +(1)(2022MY%)]. The 2017 MY portion of the 

calculation would not be included if the manufacturer used the “PZEV zero evap 

only” nationwide option and thus started the alternative phase-in scheme in the 

2018 MY. Under the regulations, EPA has the authority to question elements of the 

plan and to seek clarifications and potential changes as needed. EPA could 

disapprove the plan and potentially not allow the use of an alternative phase-in 

scheme for the model year of interest if the manufacturer does not present a viable 

explanation and rationale as to how the required numerical sum for the phase-in 

would be achieved. 

EPA also sought comment on including the 20 percent value hot soak plus 

diurnal value from the 20/20 option described above for 2017MY in this 

calculation. Manufacturers generally supported including the 2017 MY in the 

calculation but did not clearly state whether the 40 percent or 20/20 option approach 

or both were supported. EPA has decided to include both options for the 2017MY 

in the alternative phase-in percentage scheme; 40 percent as described above or 20 

percent, with the stipulation that any vehicle used to meet the 20 percent 
Page 213 of 529

requirement in the 2017MY would also have to meet the OBD evaporative leak 

monitoring requirements and the leak standard. In other words, the flexibility of 

using different vehicles as allowed for the 20/20 option in the primary phase-in 

scheme is not included in the alternative phase-in. Including this restriction avoids 

the complexity that would be added if two different sets of vehicles were allowed to 

meet the two elements of the 20/20 option for the 2017 MY, as in the primary

phase-in (e.g., expanding the calculation and tracking requirements and 

incorporating leak standard compliance and OBD evaporative system monitoring as 

part of the alternative phase-in scheme). If a manufacturer’s hot soak plus diurnal 

value exceeded 20 percent then that larger value could be used in the alternative 

phase-in calculation. However, the leak standard value cannot be less than 20 

percent and for the first 20 percent the hot soak plus diurnal and the leak must be on 

the same vehicle and that vehicle must meet the 0.020”OBD evaporative system

leak monitoring requirement. Compliance would be calculated in the following 

manner: [(6)(2017MY%)+(5)(2018MY%)+(2019MY%)+3(2020MY%) +

2(2021MY%) +(1)(2022MY%)]. If choosing the 20/20 option approach for MY 

2017, the value to be met or exceeded in the alternative phase-in would be 1160 

which is based on substituting the required phase-in percentages for MYs 2017-

2022 in the equation. Under this option as above, before the 2017 MY, the 

manufacturer would have to submit a plan to EPA which demonstrates that the sum 

of the products of a weighting factor and the percentages of their U.S. vehicle sales 

for each model year from 2017 through 2022 is greater than or equal to 1160. A 

manufacturer that over complies with the targets (i.e., 1040, 1160, 1280) may not 

trade the excess to another manufacturer. Also, a manufacturer must include all of 

its affected products in program, not just specific vehicle categories or 

subcategories. 

A manufacturer’s alternative phase-in plan must be approved by EPA prior 

to the start of production for a given model year and will have to be reviewed with 

EPA each subsequent model year to confirm that the manufacturer’s target 

percentages are being met. This would be expected to occur at the annual 

certification preview meeting. Manufacturers not meeting their target goals must 

present revised plans for EPA approval to show how the target percentages and 

equivalent emission standards will be met. Manufacturers using the alternative 

phase-in percentage scheme must still show compliance with the hot soak plus 

diurnal standards in each year as discussed in Section IV.C.2.d.iii even if they fall 

short of their individual target goal percentages for a given year. EPA is not 

requiring that manufacturers include Tier 2 vehicles in the calculation for a given 

model year if they fall short of projections (e.g., if a manufacturer projects 25% in a 

given model year but only achieves 22%) because it will have to be made up in a 

subsequent year using a lower multiplier.
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c. Allowance Program

We are finalizing incentives for early introduction of vehicles compliant 

with the Tier 3 evaporative emission regulations. Manufacturers can take 

advantage of these incentives prior to MY 2018 by selling vehicles that meet the 

Tier 3 evaporative emission regulations earlier than required or in greater numbers 

than required. Vehicle eligibility requirements for the allowance program are 

summarized in Table IV-23. Refer to the regulatory text for specific provisions.

Table IV-23 Vehicle Eligibility to Earn Allowances & Test Fuel Requirements

Model Year

& Program

Vehicle 

Category

HS+DI / 

Running 

Loss

Rig Canister 

Bleed 

High 

Altitude & 

Refueling

/Spitback*

 EVAPORATIVE EMISSIONS

2015-2016

PZEV zero 

evap 

carryover

LDV,

LDT

CA Ph. 

2

CA 

Ph. 2

N/A EPA Tier 

2/ Tier 3

2015-2016

LEV III 

Option 1

LDV, 

LDT

CA Ph. 

3

CA 

Ph. 3

N/A EPA Tier 

2/ Tier 3

2015-2016

LEVIII 

Option 2

All CA Ph. 

3

N/A CA Ph. 

3

EPA Tier 

2/ Tier 3

2015-2016

Tier 3

All Tier 3 N/A Tier 3 EPA Tier 3

2017 

“PZEV evap 

only”

carryover

LDT 3&4 CA Ph. 

2

CA 

Ph. 2

N/A EPA Tier 

2/ Tier 3

2017 

“Percentage

” option -

LEVIII 

Option 1

LDT3 &4 

MDPV, 

HDGV

CA Ph. 

3

CA 

Ph. 3

N/A EPA Tier 

3

2017 

“Percentage

” option

LEVIII -

Option 2

LDT3/4 

MDPV, 

HDGV

CA Ph. 

3

CA 

Ph. 3

CA Ph. 

3

EPA Tier 

3

2017 LDT3/4 Tier 3 EPA EPA EPA Tier 3
Page 215 of 529

“Percentage

” option

Tier 3

MDPV, 

HDGV

Tier 3 Tier 3

2017 

“20/20” and 

all MY alt 

phase-in 

schemes

Not 

available

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

2018+ LDV, 

LDT, 

MDPV & 

HDGV

Not 

available

 ORVR***

2015-2017

Early 

ORVR

Complete 

HDGV>

10,000

but 

<14,000

lbs.

GVWR

--- --- --- EPA Tier 

2/ Tier 3

2015-2021

Early 

ORVR

Complete 

HDGV>

14,000

lbs.

GVWR

EPA Tier 

2/ Tier 3

2015-2021

ORVR

Incomple

te HDGV

> 8,500

lbs. 

GVWR

EPA Tier 

2/ Tier 3

* LHDGVs are heavy-duty gasoline vehicles with a GVWR equal to or less than 

14,000 lbs; HHDGVs are heavy-duty gasoline vehicles with a GVWR in excess of 

14,000 lbs.

** Incomplete HDGVs without ORVR may defer demonstrating compliance with 

the spit back requirement on Tier 3 fuel until the 2022 MY.

*** All ORVR certifications must use Tier 3 fuel by the 2022 model year

As described below, manufacturers can earn “allowances” for selling any 

vehicle meeting the Tier 3 evaporative emission program requirements as specified 

in Table IV-21 earlier than required. The vehicles may be LDVs, LDTs, MDPVs, 

or HDGVs. Specifically, the allowance program includes the following: (1) for 

MYs 2015 and 2016, any LDVs and any LDTs meeting the Tier 3 evaporative 
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emission program requirements as specified in Table IV-21 which are sold outside 

of California and the states that have adopted CARB’s ZEV or LEV III programs, 

(2) for MYs 2015-2017, any MDPV or HDGV meeting the Tier 3 evaporative 

emission program requirements as specified in Table IV-21 early and sold in any 

state, (3) for MY 2017, any LDT3/4 meeting the Tier 3 evaporative emission

program requirements as specified in Table IV-21 and sold outside of California 

and the states that have adopted CARB’s LEV III or ZEV programs, and (4) for 

MYs 2015-2017, any complete or incomplete HDGV with a GVWR greater than 

10,000 lbs meeting the EPA refueling emissions regulations and sold outside of 

California and the states that have adopted CARB’s LEV III program. EPA asked 

for comment on extending the ORVR requirement to all HDGVs, complete and 

incomplete. As discussed in section IV.C.4.b, we are extending ORVR to all 

complete vehicles over 14,000 lbs GVWR, but are not including incomplete 

vehicles over 8,500 lbs GVWR in the ORVR requirement at this time. However, 

we are permitting complete vehicles over 14,000 lbs GVWR and incomplete 

HDGVs meeting the refueling emission standard to earn allowances through the 

2021 MY. Any complete or incomplete HDGV eligible to earn allowances for the 

model years and areas discussed above will earn them at a 1:1 rate for refueling 

emissions compliance purposes and at a 2:1 rate for Tier 3 evaporative emissions 

purposes because the refueling emission reductions are much larger. 

Furthermore, for the 2017 MY, manufacturers choosing EPA’s “percentage” 

option (see Section IV.C.2.a) could earn allowances for sales of LDT3s, LDT4s, 

MDPVs, and HDGVs that meet the CARB LEV III or Tier 3 evaporative emission 

standards and related requirements assuming their LDV, LDT1/2 sales meet the 40 

percent requirement. Similarly, manufacturers choosing EPA’s “PZEV zero evap 

only” option could earn allowances in MY 2017 for LDT3/4s, MDPVs, and 

HDGVs that meet the “PZEV zero evap” evaporative emission standards, CARB 

LEV III, or EPA Tier 3 evaporative emission standards and related requirements. 

EPA has decided not to include allowances for the 2017MY for any manufacturer 

using the 20/20 option since it would involve identifying not only the vehicles 

exceeding the 20 percent for the Tier 3 evaporative emission requirements but also 

the vehicles exceeding the 20 percent for the leak standard and these may be 

different vehicles. For both the “percentage” and “PZEV zero evap only” options 

for the 2017 model year, to avoid double counting, the allowances will be earned 

only for those vehicles sold outside of California and the states that have adopted 

CARB’s LEV III/ZEV program requirements.

 To qualify as a Tier 3 vehicle for evaporative emission allowance purposes 

the vehicle must meet the requirements summarized in Table IV-21. Manufacturers 

will earn one allowance for each qualifying vehicle sold. Manufacturers can use 

these allowances in MY 2017 through 2022 to help demonstrate compliance with 

the phase-in percentage requirements and fleet average evaporative emission 

standards for those years. Since credits and allowances serve primarily the same 

purpose and allowing for splits of allowances/credits greatly complicates program 
Page 217 of 529

implementation, the final rule provides that manufacturers can only earn allowances 

in MYs 2015-2016 for any LDVs and LDT1/2s meeting the Tier 3 evaporative 

emission regulations which are sold outside of California and the states that have 

adopted CARB’s ZEV or LEV III programs and for .MYs 2015-2017 for any

qualifying LDT3/4, MDPV, and HDGV.354

Allowances will be used in the compliance determination in the following 

manner. Vehicles qualifying for allowances can be used in the fleet average 

evaporative emission standard calculation for any year during the phase-in. This 

applies to the primary phase-in and alternative phase-in programs. Allowance 

vehicles will be entered into the compliance calculation with an emission value 

equivalent to the evaporative emission standard for their vehicle category from 

Table IV-18 even if it was certified to CARB PZEV zero evap or LEV III Option 1 

standards (Table IV-19). For the percent phase-in requirement in either the primary

or alternative phase-in schemes, allowance vehicles will count for one vehicle for 

each allowance used within their vehicle category. For the primary scheme this will

be counted as one vehicle, but for the alternative phase-in option the value will be 

multiplied by the weighting factor (6 for 2017, 5 for 2018, 4 for 2019, 3 for 2020, 

etc). Within the alternative phase-in scheme the manufacturer will be limited to 

using these early allowances for no more than 10 percentage points of the phase-in 

requirements in any given model year (e.g., MYs 2017-2022). EPA believes this 

limitation is appropriate since early use in the alternative phase-in scheme is 

multiplied and early introduction of “zero evap” technology should be encouraged, 

but not necessarily at the expense of its widespread use across the various vehicle 

categories as the phase-in progresses. The allowances are designed primarily to 

facilitate manufacturer transition during the program phase-in. As such, they may

not be traded between manufacturers and unused allowances will expire after the 

2022 MY. 

An example here may be helpful in demonstrating how allowances will

work. Take a hypothetical manufacturer who earned a total of 10,000 allowances in 

MYs 2015 and 2016 and sells 100,000 units per year. In MY 2018, the 

manufacturer will have a phase-in requirement of 60 percent or 60,000 vehicles. 

For the primary phase-in option the manufacturer could use part or all of its 

allowances in 2018 without restriction. For the alternative phase-in scheme assume 

the manufacturer set its alternative phase-in value at 60 percent for the 2018 MY. 

The final regulations limit the use of allowances to 10 percentage points of the 60 

percent or in this case 10,000 vehicles out of 60,000. Without a multiplier this will

require the use of all 10,000 allowances in 2018, but with the multiplier of 5 for 

 

354 LDVs and LDT1/2 sold in California and states which have adopted the LEV III or ZEV 

programs cannot generate allowances because these programs will already require zero evap 

technology vehicles in those states in MYs 2015-2016. 
Page 218 of 529

MY 2018 only 2,000 allowances are needed to reach the 10 percentage point 

maximum. Using a similar calculus, the manufacturer could use another 10 

percentage points in MY 2019, but it will require 2,500 allowances to reach this 

level since the multiplier is 4 assuming sales remain at 100,000 units per year. The 

number of allowances to reach the 10 percentage point level will increase each year 

as the multiplier decreases.

d. Evaporative Emissions Averaging, Banking, and Trading

i. Introduction

Throughout EPA’s programs for mobile source emission controls, we have 

often included emission averaging programs for exhaust emissions. An emission 

averaging program is an important factor we take into consideration in setting 

emission standards under the Clean Air Act. An emission averaging program can 

reduce the cost and improve the technological feasibility of achieving standards, 

helping to ensure the standards achieve the greatest achievable reductions, 

considering cost and other relevant factors, in a time frame that is earlier than might 

otherwise be possible. Manufacturers gain flexibility in product planning and the 

opportunity for a more cost-effective introduction of product lines meeting a new 

standard. Emission averaging programs also create an incentive for the early

introduction of new technology, which allows certain emission families to act as 

leaders for new technology. This can help provide valuable information to 

manufacturers on the technology before they apply the technology throughout their 

product line. 

These programs generally involve averaging and banking, and sometimes 

trading (ABT). Averaging allows a manufacturer to certify one or more families at 

emission levels above the applicable emission standards as long as the increased 

emissions are offset by one or more families certified below the applicable 

standards. These are referred to as individual family emission limits (FELs). The 

over-complying families generate credits that are used by the under-complying

families. Compliance is determined on a total mass emissions basis to account for 

differences in production volume, and on other factors as necessary such as useful 

life. The average of all emissions for a particular manufacturer’s production within 

a vehicle category must be at or below the level of the applicable emission 

standards. Banking allows a manufacturer to generate emission credits and bank 

them for future use in its own averaging program in later years. Trading allows a 

manufacturer to sell credits or obtain credits from another manufacturer.

EPA proposed and is finalizing an emissions ABT program for the Tier 3 

hot soak plus diurnal evaporative emissions standards. The evaporative emissions 

ABT program is generally structured and operates the same as that for exhaust 

emissions as discussed in Section IV.A.7.m. The major difference is the added 

requirement to reconcile compliance with the fixed percentage requirement as 
Page 219 of 529

discussed in detail in Section IV.C.2.a. Also, there is a five year credit life for 

evaporative emissions as opposed to the longer interim values for NMOG+NOx 

FTP and SFTP credits. 

This is the EPA’s first averaging type program for evaporative emissions 

from light-duty or heavy-duty vehicles. It does not apply to the canister bleed 

standard or the leak standard because it is the low altitude “zero evap” hot soak plus 

diurnal standard which will drive the fundamental approach used to comply with all 

of these requirements. We sought comment on the value of including trading in the 

program. The comments from the Alliance of Automobile Manufacturers and the 

Association of Global Automakers very generally supported the inclusion of trading 

but provided no detail. Upon follow-up from EPA no manufacturer provided any 

further explanation on the need for the program or how they might use it.355 In past 

similar programs for exhaust emissions there have been only a few trades, but 

incorporating trading within the program adds a degree of flexibility if a 

manufacturer finds itself in a credit deficit situation. Thus, we have decided to 

include trading, but credit trades are limited based on the same averaging set 

restrictions as discussed below for averaging and banking.

The evaporative emissions ABT program will start with the 2017 MY for

the percentage and 20/20 options. Prior to the 2017 MY and for other options as 

discussed in Section IV.C.2.b, manufacturers may earn allowances. The programs 

will continue for the 2018 MY and beyond for all manufacturers regardless of their 

2017 MY option and will not sunset, as does the allowance program. Vehicles 

generating ABT credits in the 2017 MY or later will not be permitted to also 

generate allowances as this would be double counting.

A key element of an averaging program is the identification of the averaging 

sets. This establishes the basis within which evaporative emission families can be 

averaged for purposes of compliance as well as credit and deficit determinations. As 

proposed, we are finalizing four averaging sets and the applicable emission standard 

for each of the averaging sets as shown in Table IV-18. Except as noted in Section 

IV.C.2.d.2 below, credit exchanges between averaging sets will not be permitted. 

Participation in ABT is voluntary since a manufacturer could elect to certify each 

family within the averaging set to its individual standard as if there were no 

averaging program. 

An evaporative emission ABT calculation and assessment involves two 

distinct steps. The first is the determination of the credit/deficit status of each 

family relative to its applicable standard from Table IV-18. The second is the role 

 

355 See Alliance of Automobile Manufacturers and Association of Global Automakers comments on 

the NPRM (dated July 1, 2013) and Passavant, G. (June 2013 ) EPA and Auto Industry Meeting 

Related to Tier 3 Evap and OBD NPRM. Memorandum to the docket.
Page 220 of 529

of ABT calculations in the overall compliance demonstration which is discussed in 

Section IV.C.2.d.

ii. Family Emission Limits

A manufacturer choosing to participate in the evaporative emissions ABT 

program will certify each emission family to an FEL that applies for the hot soak 

plus diurnal standard for low altitude testing. The FEL selected by the 

manufacturer becomes the emission standard for that emission family. Emission 

credits (or deficits) are based on the difference between the emission standard that 

applies (by vehicle category) and the FEL. The vehicles will have to meet the FEL 

for all emission testing. As mentioned in Section IV.C.1.b., above, for vehicles 

certified with FELs above or below the applicable standard for testing at low 

altitude, the same differential will apply to the FELs for high-altitude. This highaltitude FEL will not be used for any emission-credit calculations, but it will be 

used as the emission standard for compliance purposes. 

The final rule provides that the FELs selected by the manufacturer must be 

selected at 0.025 g/test increments above or below the applicable Tier 3 evaporative 

emission standards for each vehicle category. For example, for LDVs the 

increments for the FELs would be +/- 0.025 from 0.300 g/test (e.g., 0.225, 0.250, 

0.275, 0,300, 0.325, 0.350, 0.375 ... 0.500). The FEL is used in the compliance 

demonstration not the certified level. The certified level must be below the FEL, 

but the FEL could be a higher value than the closest increment value. For example, 

a certified value of 0.235 g/test could support an FEL of 0.250 g/test or any other 

higher increment value. One commenter asked that the gradation be finer than 

0.025 g/test, but EPA believes this is the appropriate increment, since the standard 

itself is the sum of two values and rounding of the measured values is involved.

FELs are capped such that they cannot be set any higher than 0.500 g/test 

for LDVs, 0.650 g/test for LDT1s and LDT2s, 0.900 g/test for LDT3s and LDT4s, 

1.000 g/test for MDPVs, 1.4 g/test for HDGVs at or below 14,000 lbs GVWR, and 

1.9 g/test for those above 14,000 lbs GVWR, respectively. These FEL caps are the 

3-day hot soak plus diurnal emission standards applicable under EPA’s existing 

regulations. While we asked for input on these FEL caps and vehicle groupings, no 

party provided comment.

Total evaporative emission credits (or deficits) under the Tier 3 hot soak 

plus diurnal ABT program will be calculated differently in the 2017 model year and 

the 2018 and later model years. For 2017 calculations will be based on sales in the 

U.S. excluding California and the section 177 states which have adopted the LEV 

III/ZEV programs. For 2018 and later model years it will be based on all 50 states. 

Calculations will use the following equation: Credits = (fleet average standard –

fleet average FEL) × “U.S. sales”. The “fleet average standard” term here is the 

applicable Tier 3 hot soak plus diurnal standard for the vehicle category from Table 
Page 221 of 529

IV-18. The sales number used in the 2018 and later MY calculation will be the 

number of vehicles of the evaporative emission families in that category sold in the 

U.S. which are subject to the Tier 3 evaporative emission standards. Emission 

credits banked under the evaporative emission ABT program will have a five year 

credit life and will not be discounted. This means the credits will maintain their full 

value through the fifth model year after the model year in which they are generated. 

At the beginning of the sixth model year after they are generated, the credits will

expire and cannot be used by the manufacturer. We are limiting credit life so there 

is a reasonable overlap between credit generating and credit using vehicles. As 

mentioned above, for purposes of the compliance calculation, allowance vehicles 

will have an FEL equivalent to the EPA emission standard (Table IV-18) for their 

respective vehicle category. 

iii.Compliance Demonstration

Demonstration of compliance with the evaporative emissions standards is

done after the end of each model year. There are two steps. In the first step, as 

discussed above, manufacturers must show compliance with the applicable phase-in 

percentages from the primary phase-in scheme (i.e., 40, 60, 80, and 100), the 20/20 

option for MY 2017, or an alternative phase-in percentage scheme. It is sales from 

these families together with their respective FELs which will be used to make the 

demonstration of compliance with the emission standard on average within each 

vehicle averaging set. Compliant vehicle types for these purposes are the same as 

described in Section IV.C.1.c above for projected sales. If the required sales 

percentages are not met by direct sales or allowances, non-Tier 3 vehicles would

have to be identified to make up the shortfall in this calculation but would not be 

subject to the canister bleed or leak standard requirements.

 In the second step, using the FELs, manufacturers calculate the salesweighted average emission levels within each of the four vehicle categories using 

sales for each family.

356

 Manufacturers are allowed to use credits only within a 

defined averaging set. The averaging sets are: (1) LDVs and LDT1s, (2) LDT2s, 

(3) LDT3s, LDT4s, and MDPVs, and (4) HDGVs. These sales-weighted calculated 

values must be at or below the emission standard for that vehicle category as shown

in Table IV-18, (unless credits from ABT are used). If the difference between the 

standard and the sales-weighted average FEL is a positive value this could generate 

banked credit available for future use. If the difference between the standard and 

the sales-weighted average FEL is a negative value this would be a credit deficit

which could be covered by previously banked credits. Credit deficits will be 

 

356 For MY 2017 calculations will be based on sales in the U.S. excluding California and the section 

177 states which have adopted the LEV III/ZEV programs. For 2018 and later model years it will be 

based on all 50 states.
Page 222 of 529

allowed to be carried forward through negative banking. However, manufacturers 

are required to make up any deficits within the three subsequent model years with 

credits from vehicles in the same averaging set, except as described below. That is, 

after calculations for the fourth model year are complete, all previous deficits from 

the preceding model years will have to be resolved by credits generated by the 

manufacturer or acquired through trading from vehicles within the same averaging 

set. As an illustration, a credit deficit accumulated in MY 2017 would have to be 

eliminated not later than the time that the 2020 MY ABT calculation is submitted to 

EPA. In no case will a manufacturer be permitted to carry a deficit (negative credit 

balance) for more than three consecutive model years. Using a similar illustration, 

all credit deficits accumulated in MYs 2017, 2018, and 2019 would have to be 

eliminated not later than the time that the 2020 MY ABT calculation is submitted to 

EPA. 

As discussed above, manufacturers are required to identify and include in 

the calculations for each of the four averaging sets, vehicle families from each of 

the vehicle categories (see Table IV-18) until the total annual nationwide sales in 

the given model year equals or exceeds the prescribed percentages. This could 

include non-Tier 3 vehicles. If the inclusion of non-Tier 3 vehicles results in an 

exceedance of the hot soak plus diurnal emission standard for that category of 

vehicles, the credit deficit would have to be made up in a subsequent model year. 

Credits from banking and trading can be used to cover deficits at any time within 

the appropriate averaging set. 

Allowances can also be used to demonstrate compliance with the percentage 

phase-in requirements and the vehicle category average emission standard. For 

purposes of the percentage phase-in requirements, vehicles which have earned 

allowances are counted as compliant in the percentage calculation. For purposes of 

the calculations for compliance with the emission standard, allowance vehicles 

enter into the evaporative emissions compliance calculation as having an emission 

rate equivalent to the standard for that category of vehicle. Thus, allowance 

vehicles can help in demonstrating compliance with the percentage phase-in 

requirement (up to ten percentage points per model year in the alternative phase-in 

scheme) and can help in reducing deficits since their calculation value is equivalent 

to the level of the standard. 

 As presented in detail above, during the 2017-2021 MYs EPA is allowing 

manufacturers limited flexibility to meet the percentage phase-in requirements 

using carryover certification data from vehicles certified to CARB PZEV zero evap 

and CARB LEV III Option 1 standards in the 2015 or 2016 model years. These 

vehicles may have certification values slightly higher than those of EPA’s Tier 3 

program for the given vehicle and vehicle category. Since the emission standard 

values in Table IV-18 and Table IV-19 are very similar for any given vehicle 

category, for purposes of simplification during the phase in, EPA in the final rule 

provides that any CARB PZEV zero evap or CARB LEV III Option 1 vehicles used 
Page 223 of 529

in the 2017-2021MYs emission standard compliance determination be entered into 

the calculation with the emission level equivalent to the Tier 3 vehicle category in 

which the vehicle model would otherwise fit. However, we are not allowing 

manufacturers to generate emission credits for families certified with EPA based on 

carryover CARB PZEV zero evap or CARB LEV III Option 1 evaporative 

emissions data as provided for in Table IV-19. We are not including these vehicles 

in the ABT program since the programs are not directly comparable, and the 

structure of the current CARB ZEV program, which is the genesis of most PZEV 

zero evap offerings, allows for a different number of PZEV sales as a function of 

manufacturer size and CARB LEV III Option 1 does not permit averaging.

 As mentioned above, we are limiting use of credits to only within a defined 

averaging set. Cost effective technology is available to meet the hot soak plus 

diurnal emission standards on average within each of the vehicle categories in the 

averaging sets, especially since the standards are designed to accommodate nonfuel 

hydrocarbon background emissions. Thus, further flexibility is not needed. 

Moreover, we are constraining averaging to within these sets because of equity

issues for the manufacturers. We are concerned that in the absence of such 

constraints the four or five manufacturers with a wide variety of product offerings 

in most or all of these categories would have a competitive advantage over the 

majority of manufacturers which have more limited product lines. This effect could 

be even more pronounced if the number of evaporative families is considered, since 

larger more diverse manufacturers have more models and thus more evaporative 

families. 

Nonetheless, manufacturer use of credits from different averaging sets to 

demonstrate compliance is permitted in limited cases. As noted above, if a 

manufacturer has a credit deficit at the end of a model year in a given averaging set, 

they will have to use credits from the same averaging set during the next three 

model years to make up the deficit. However, if a deficit still exists at the end of 

the third year (i.e., the deficit has existed for three consecutive model years) , we 

are incorporating provisions to permit a manufacturer to use banked or traded 

credits from a different averaging set to cover the remaining deficit in the fourth 

model year’s ABT calculation, with the following limitations. Manufacturers are

able to use credits from the LDV and LDT1 averaging set to address remaining 

deficits in the LDT2 averaging set, and vice versa. Furthermore, manufacturers are

permitted to use credits from the LDT3, LDT4, and MDPV averaging set to address 

remaining deficits in the HDGV averaging set, and vice versa. No other use of 

credit exchanges across different averaging sets is allowed. These restrictions are 

being finalized because of equity concerns caused by the different nature and size of 

various manufacturer product lines. 

For both the percentage phase-in and sales-weighted average calculation 

steps above, we are basing the calculation on nationwide sales (excluding California 

and the section 177 states which have adopted the LEVIII/ZEV programs) in the 
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2017 MY since the anti-backsliding provisions of the LEV III evaporative 

emissions program are in place through the 2017 MY. The program uses annual 

nationwide sales beginning in the 2018 MY. We believe this approach is consistent 

with the manufacturers’ plans for 50-state vehicles. A program design which 

enables a nationwide program has been an important premise of this rulemaking. 

Furthermore, this is simpler for the manufacturers and for EPA since it relieves the 

need to project future model year sales or track past model year sales at a 

disaggregated level. We recognize that decisions by the manufacturers on a 

national fleet versus a bifurcated approach such as exists today (California and the 

section 177 states which have adopted the LEVIII/ZEV programs separate from the 

rest of U.S. sales) may not yet have been made. The CARB LEV III and EPA 

phase-in requirements are identical beginning in 2018, so EPA sees little need for 

concern that a nationwide-based accounting approach could lead to disproportionate 

state by state impacts or the encouragement of practices which would lead to any

particular state or area not receiving the anticipated emission reductions with this 

nationwide approach to the calculation. 

As discussed above, manufacturers not meeting the percentage phase-in 

requirements will need to include non-Tier 3 vehicles in the count and include their 

emissions in the overall calculation of compliance with the hot soak plus diurnal 

standard and resolve shortfalls in compliance with the emission standard with future 

reductions, earned allowances, or credits. These non-Tier 3 vehicles would not be 

subject to leak standard or canister bleed standard requirements. The additional 

vehicles could only be meeting the Tier 2 hot soak plus diurnal requirements and 

adding these vehicle families/vehicles into the calculation may result in a credit 

deficit. A manufacturer could not have an unresolved deficit for more than three 

model years as discussed below. The deficit would have to be eliminated with 

positive credits not later than the ABT calculation and credit reconciliation which 

occurs after the fourth model year.

Resolving this sales percentage shortfall problem becomes a bit more 

complicated for the 2017 MY 20/20 option because it requires that 20 percent of 

vehicles meet the Tier 3 evaporative emission requirements and that 20 percent 

meet the leak standard. These may or may not be the same vehicles. As a means to 

resolve this potential problem, EPA is requiring that any shortfall of either of the 20 

percent values (Tier 3 evaporative or leak standard) for the 2017 MY be covered by 

allowances or by future sales of vehicles meeting the Tier 3 evaporative emission 

requirements in excess of the evaporative emission percentage sales requirement for 

that MY or some combination of MYs. For example, if a manufacturer was five

percentage points short of either the 20 percentage points for the hot soak plus 

diurnal or the 20 percentage points for the leak standard in the 2017 MY, then it 

will have to accelerate sales of vehicles meeting Tier 3 evaporative emission 

requirements in the 2018-2021 MYs to cover the 5 percentage points (e.g., 65 

percent in 2018 instead of 60 percent or 63 percent in 2018 MY and 62 percent in 
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the 2019 MY, etc.). These vehicles as Tier 3 vehicles in MY 2018 or later would 

also have to meet the leak standard.

e. Small Volume Manufacturers 

As flexibility, we are establishing provisions for small volume 

manufacturers and for those small business manufacturers and operationally

independent small volume manufacturers with average annual nationwide sales of 

5,000 units or less.

357

 These manufacturers would be permitted to delay meeting 

the Tier 3 evaporative emission standards, including the requirement to use EPA 

certification test fuel, until the 2022 MY. See pages 29892 and 29998-29999 of the 

preamble to the NPRM and Section IV.G.5 below for a discussion of the 5,000 

vehicle threshold. This includes the hot soak plus diurnal standards, the canister 

bleed emission standard, and the leak standard. In the interim, these vehicles must

meet the existing evaporative and refueling emission standards. The initial 

determination of whether a manufacturer is under the 5,000 unit threshold will be 

based on the three year average of actual nationwide sales for MYs 2012-2014. 

This allowance would not be affected if a qualifying manufacturer’s nationwide 

sales later exceed that value before 2022. Similarly, new market entrants (not in the 

market in the 2012 MY) with projected sales of less than 5,000 units could be 

covered by the small volume manufacturer provisions. However, in this case if 

actual running average nationwide sales exceed 5,000 units per year in any three 

consecutive model years they will have to meet the Tier 3 evaporative requirements 

in the third model year thereafter. For example, if a new market entrant in 2015 

projects nationwide production of 4,000 units per year and the average of actual 

values in 2015-2017 exceeds 5,000 units per year they will have to meet Tier 3 

evaporative requirements by the 2020 MY.

3. Technological Feasibility

Evaporative/refueling emission control systems are an integral part of the 

overall vehicle engine and fuel system. EPA is establishing two revised and three 

new standards in this rule (2-/3-day hot soak plus diurnal standards, high altitude 

standards canister bleed standards, fuel rig SHED standard, leak standard) and a 

new test fuel which applies to these standards as well as the current running loss, 

refueling, and spit back emission standards. 

Hot soak plus diurnal emissions are fuel vapors which arise from the fuel 

system when it is parked immediately after operation (hot soak) and during daily

ambient heating and cooling or by means of permeation when the vehicle is at rest. 

Control of hot soak plus diurnal emissions is primarily achieved by routing fuel 

 

357 See 40 CFR§86.1838-01(d).
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vapors to a canister filled with activated carbon. These vapors are stored on the 

carbon and purged in the engine during vehicle operation. Hot soak plus diurnal 

emission rates vary with fuel vapor pressure, temperature, and fuel system design. 

Permeation emissions have been reduced by improving fuel tank and fuel line 

materials. Permeation emissions are sensitive to the gasoline ethanol content. 

While EPA has required ethanol in the fuel used for assessing evaporative system 

durability since 2004, Tier 3 is the first rule to require the certification test fuel for 

gasoline-fueled vehicles to include ethanol (E10).

Canister bleed emissions are fuel vapors which diffuse from the canister 

vent as a result of the normal redistribution of vapors within the activated carbon 

while the vehicle is at rest. The emission rate depends on the tank volume, its fill 

quantity, the size and architecture of the canister and the characteristics of the 

carbon itself. While the biggest effect of this vapor redistribution is a uniform 

vapor concentration within the canister, it can also cause vapors to escape through 

the canister vent even without continued canister loading resulting from fuel tank 

heating. 

Vapor leaks in the vehicle fuel/evaporative system can arise from microcracks or other flaws in various fuel/evaporative system component structures or 

welds, problems with component installations, and more generally from 

connections between components and fuel lines and vapor lines. Control of leaks is 

especially important to achieving full useful life emission control system 

performance. 

In Tier 3, the emissions test fuel is changing from 9 RVP E0 to 9 RVP E10. 

EPA does not expect the change in emissions test fuel to affect refueling, spit back, 

or running loss compliance technology or strategies.

While these elements of the evaporative/refueling program are separate 

requirements for compliance purposes, the integrated nature of the design and 

operation of the evaporative/ refueling control systems and the vehicle engine/fuel 

systems often leads to co-benefits when technology is added or upgraded. In some 

cases technology to meet one of the new or revised evaporative emission 

requirements will either help in efforts to meet other evaporative type requirements 

or enhance durability. For example, technology used to address the canister bleed 

standard will also reduce hot soak plus diurnal emissions and technology to meet 

the leak standard will reduce hot soak plus diurnal emissions and enhance 

durability.

Based on review of current certification data and the documentation in 

current professional literature, there is no doubt that the technology is available to 
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meet the final evaporative emission standards described in this rule.358 There are at 

least 50 vehicle models which met the requirements in 2013.359 There are many

technologies manufacturers can consider which will reduce emissions and enhance 

durability. Manufacturer compliance options and cost considerations are also 

addressed by the phase-in flexibilities and as the ABT program.

In the NPRM we described a variety of technology approaches and 

calibrations which manufacturers could use to meet the Tier 3 evaporative emission 

requirements. No comments were provided on the stringency of the standards, the 

technologies, the feasibility of the standards, or the costs of compliance. 

Nonetheless, we updated our technology analysis in light of new certification data 

and vehicle technology projections. As in the analysis supporting the NPRM, we 

identified technologies on the basis of their control effectiveness and cost to 

implement. Not every model will use every technology described below. Rather we 

expect manufacturers to apply the technologies needed on any given model to meet 

the compliance target level. The technologies could be broadly grouped into two 

segments. The first are those expected to see widespread use based on their 

effectiveness and cost to implement. The second are those which are in relatively

widespread use today, but could be optimized if necessary to achieve further 

reductions. In many cases the reductions available from this second group are 

relatively small and the costs are slightly higher than for the other strategies. The 

anticipated control technologies to comply with the hot soak plus diurnal, canister 

bleed/rig, and leak standards are described briefly below and are grouped in these 

two basic segments. A more detailed analysis for each vehicle category is found in 

Chapter 1 of the Regulatory Impact Analysis (RIA). 

a. Technologies expected to see widespread use:

Engine/fuel system conversion: As projected in our RIA for the 2017-2025 lightduty GHG emissions final rule, EPA projects a significant movement from port fuel 

injection (PFI) engines to gasoline direct injection (GDI) engines. This ranges from 

60-100 percent of products for all categories except gasoline-powered trucks over 

14,000 lbs GVWR. This reduces air induction systems emissions by 90 percent.

Air Induction System (AIS) Scrubber: For vehicles/engine models not converted to 

GDI, EPA projects the use of an AIS scrubber as is now used on some PZEV 

models. These would reduce air induction system emissions by 85 percent. 

Canister honeycomb: This is a lower gasoline working capacity activated carbon 

device designed to load and purge very easily and quickly. This device reduces 

 

358 Passavant, G. (December 2013). Assessment of 2013 MY Evaporative Emission Results. 

Memorandum to the docket.

359 See Chapter 1 of the RIA for more detail.
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canister bleed emissions by 90 percent but also provides control for the hot soak 

plus diurnal test. 

Reduce leaks from connections and improve seals and o-rings: Vapor leaks from 

connections and the emission rates from these leaks is exacerbated if poor sealing 

techniques or low grade seal materials are use in connectors such as o-rings. 

Reducing connections in the fuel and evaporative systems and improving 

techniques and materials would reduce these emissions by 90 percent. This would 

reduce hot soak plus diurnal emissions, improve durability, and help to assure 

compliance with the leak standard.

Move parts into the fuel tank: Another means to reduce leak-related vapor 

emissions is to move fuel evaporative system parts which are external to the fuel 

tank to the inside. Emissions from these parts would be completely eliminated. This 

would reduce hot soak plus diurnal emissions, improve durability, and help to 

assure compliance with the leak standard.

OBD evaporative system leak monitoring: Beginning in the 2017 model year, the 

OBD system will need to be able to find, confirm, and signal a leak in the 

evaporative system of 0.020” cumulative diameter or greater. This is currently done 

on most vehicles less than 14,000 lbs GVWR as a result of the manufacturers’ 

response to meeting CARB requirements, but will be mandatory under EPA 

regulations. 

b. Technologies expected to be optimized if necessary to achieve 

further reductions:

In the NPRM, EPA discussed a number of other technologies with the 

demonstrated potential to further reduce evaporative emissions. These included: (1) 

upgrading the activated carbon canister and optimizing purge calibrations 

(especially for larger displacement engines), (2) upgrading fuel line materials to 

reduce permeation, (3) improving the fuel tank barrier layer to reduce permeation, 

(4) improving fuel tank manufacturing processes to reduce tank seam permeation 

emissions, (5) upgrading the fuel tank fill tube material to reduce permeation, and 

(6) improving the security of the fill tube connection to the fuel tank. While each of 

these approaches reduces evaporative emissions, they are to large degrees in use 

today. Thus their further application may be limited to specific situations. It is 

worth noting, that the use of these technologies has contributed to the relatively

large compliance margins under the existing hot soak plus diurnal standards. 

The reductions required and cost of compliance for any given vehicle model 

will depend on its current certification level and the type of evaporative emission 

control technology applied. The baseline emission values for 2-day hot soak plus 

diurnal evaporative emission certification for current models range from 0.42-0.96 

grams per test (g/test). Achieving the desired compliance targets (at least 25 percent 
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below the Tier 3 standard) would require reductions ranging from 0.12 g/test for 

LDT2s to 0.51 g/test for HDGVs.360 EPA estimates 2025MY costs in the range of 

$9-15 per vehicle with a fuel cost savings of about $2 over the vehicle life. The 

application of the technologies expected to see widespread use under Tier 3 will 

create the margins need for compliance and in some cases create excess reductions 

which could be used to generate credits for ABT.

4. Heavy-Duty Gasoline Vehicle (HDGV) Requirements 

a. Background on HDGV

HDGVs are gasoline-powered vehicles with either a GVWR of greater than 

8,500 lbs, or a vehicle curb weight of more than 6,000 lbs, or a basic vehicle frontal 

area in excess of 45 square feet.361 HDGVs are predominantly but not exclusively

commercial vehicles, mostly trucks and other work type vehicles built on a truck 

chassis. EPA often discusses HDGVs in three basic categories for regulatory

purposes according to their GVWR class. These are Class 2b (8,501-10,000 lbs 

GVWR), Class 3 (10,001-14,000 lbs GVWR), and Class 4 and above (over 14,000 

lbs GVWR). These are further sub-categorized into complete and incomplete 

vehicles.362 Class 2b HDGVs are mostly produced by the manufacturers as 

complete vehicles and are very similar to lower GVWR LDTs of the same basic 

model sold by the manufacturers. Class 3 HDGVs are also built from LDT chassis 

with fuel system designs that are similar to their Class 2b and LDT counterparts, but 

these are on some occasions sent to secondary manufacturers as incomplete vehicles 

to attach a load carrying device or container. EPA estimates that more than 95 

percent of Class 2b/3 vehicles are complete when they leave the original equipment 

manufacturer (OEM). Class 4 and above HDGVs are built on a more traditional 

heavy-truck chassis and in most cases leave the OEM as an incomplete vehicle. 

For Class 2b/3 vehicles, it is common to certify the vehicle for emissions purposes 

(exhaust, evaporative, etc) as a full chassis, while for Class 4 and above the vehicle 

is certified as a chassis for evaporative emissions while the engine is dynamometer 

certified for exhaust emissions.

HDGVs have been subject to evaporative emission standards since the mid 

1980s. Recently, the timing of the standards has lagged requirements for LDVs and 

 

360 Passavant, G. (December 2013). Assessment of 2013 MY Evaporative Emission Results. 

Memorandum to the docket.

361 MDPVs also meet the definition of HDVs, but they are classified separately for evaporative and 

refueling emission purposes. See 40 CFR 86.1803-01.

362 Heavy-duty vehicles may be complete or incomplete. A complete HDGV is one that has the 

primary load carrying device or container (or equivalent equipment) attached, normally by the 

vehicle OEM. An incomplete vehicle is one that does not have the primary load carrying device or 

container (or equivalent equipment) when it leaves control of the manufacturer of the engine. 
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LDTs by several years, but the standards are of comparable stringency when vehicle 

size and fuel tank volume are considered. The most recent 2/3 day hot soak plus 

diurnal standards for HDGVs took effect in 2008. Refueling control requirements 

apply to complete Class 2b vehicles only. These requirements phased-in over the 

period from 2004-2006.

b. HDGV Evaporative Emission Control Requirements

As discussed above, EPA is including HDGVs within the Tier 3 evaporative 

emissions program. The hot soak plus diurnal and canister bleed test emission 

standards that will apply to these HDGVs are presented in Table IV-18and-Table 

IV-19 and the high altitude standard is presented in Table IV-20. These vehicles 

will be included in the averaging calculation beginning in the 2018 MY and will be 

eligible for creating and using allowances and credits. 

Furthermore, for the reasons discussed below, EPA is requiring that all 

complete HDGVs regardless of their GVWR be required to meet the refueling 

emission standards and use the test procedures currently required for LDVs and 

LDTs and complete Class 2b vehicles. (See §86.1813-17). In their comments, 

manufacturers expressed concern about the amount of gasoline used in the 

development and certification of refueling emission control systems for HDGVs 

(due to the larger fuel tanks). To address this concern, EPA will permit 

manufacturers to certify using two separate processes for vehicles with tanks of 40 

gallons or larger. The first will be the engineering evaluation of canister and purge 

data from lighter weight HDGVs certified in the SHED to show that similar or 

scaled-up systems on heavier HDGVs have the purge volume and canister working 

capacity to pass the refueling standard. This could include a comparison of control 

system design elements such as canister shape, canister internal architecture, total 

canister volume, and total gasoline working capacity as well as purge air volume 

over the Federal Test Procedure. This would be subject to the application of good 

engineering judgment. The second is application of the provisions of 40 CFR 

86.153-98 (a) through (b)(1) on a bench set up for a tank of the appropriate volume 

in lieu of a vehicle test to show the efficacy of the fill neck seal. Such a test could 

be conducted in a conventional SHED. 

The ORVR requirement applies to complete Class 3 vehicles by the 

2018MY and all other complete HDGVs by the 2022MY. EPA proposed these 

requirements for Class 3 HDGVs and asked for comment on extending the 

requirements to all HDGVs. The manufacturers expressly commented that HDGV 

ORVR requirements should be limited to complete HDGVs.363 There are only four 

 

363 See comments of Alliance of Automobile Manufacturers and Association of Global Automakers 

in the public docket at EPA-HQ-OAR-2011-0135-4451. 
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manufacturers of HDGVs. Of these, three offer complete products in the Class 3 

weight range and none offer complete products in the Class 4 and above weight 

range. As mentioned above, Class 3 vehicles have largely the same vehicle chassis 

and fuel system configurations as Class 2b vehicles. The manufacturers of complete 

Class 2b vehicles indicated to the CARB and EPA that they carry across their Class 

2b fuel evaporative control system designs onto Class 3 and this includes the 

onboard refueling vapor recovery (ORVR) system used for control of refueling 

emissions. Thus, applying refueling emission controls to complete Class 3 vehicles 

adds no cost and has little additional emission reduction benefit. However, it does 

set a requirement to continue these controls in future model years. There are no 

complete Class 4 and above HDGVs and neither manufacturer who certifies 

incomplete HDGVs above 14,000 lbs GVWR objected to establishing an ORVR 

requirement for complete HDGVs.364 This sector is made of incomplete HDGV 

chassis and diesel-powered products. However, setting a requirement for potential 

future Class 4 and above designs establishes certainty for manufacturers but brings 

no near term cost burden or emission reductions. 

Incomplete HDGVs make up 15-20 percent of all HDGV sales. Of this, 

approximately 80 percent are Class 2b/3 and 20 percent are Class 4 and above. 

EPA is not extending the refueling emission control requirement to incomplete 

HDGVs at this time. The control system designs would be essentially the same as 

on complete HDGVs, but manufacturers have indicated to EPA that they would 

have to establish additional measures to ensure that the steps taken to complete the 

vehicle by the secondary manufacturer do not compromise the integrity and safety 

of the fuel/evaporative control system (including ORVR) and that the ORVR 

system continues to perform properly with regard to emissions control. While there 

are relatively few of these vehicles, their contributions to the inventory are larger 

than might be expected due to their lower fuel economy. Given these contributions, 

EPA may consider proposing to apply ORVR to incomplete HDGVs in a future 

action. 

EPA is also including a provision that manufacturers be permitted to comply 

with the refueling emission standard as early as the 2015 MY to earn on a one-toone basis allowances which could be used to phase-in the Class 3 refueling 

emission control requirement or as an allowance on a 2:1 basis under the Tier 3 

evaporative emission program. EPA believes this is appropriate since the expected 

daily average reduction in vehicle refueling emissions for this class of vehicles is 

large relative to the reduction in evaporative emissions expected under Tier 3. This 

would also apply to any incomplete HDGV a manufacturer voluntarily certified to 

 

364 Passavant, G., (September 2013). EPA and General Motors Meeting on Issues Related to Tier 3 

NPRM and (September 2013). EPA and Ford Meeting on Issues Related to Tier 3 NPRM. 

Memorandums to the docket.
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the refueling emission standards. Any certifications, including those done early, 

must use EPA Tier 3 test procedures and certification test fuels or CARB LEV III 

equivalents.

c. Other Program Elements for HDGVs 

In the NPRM, EPA sought comment on several provisions related to Tier 3 

certification test fuel and evaporative emission control requirements. 

First, EPA sought comment on whether heavy-duty gasoline engines 

(HDGEs) not subject to new Tier 3 exhaust emission standards (those certified for 

exhaust emissions using an engine dynamometer) which are used in HDGVs subject 

to Tier 3 evaporative emission standards should certify for exhaust emissions on 

Tier 3 emissions test fuel.365 Manufacturers responded by asking that the use of 

Tier 3 fuel for HDGE exhaust emissions certification be voluntary, but agreed that 

the use of Tier 3 certification fuel would not change the stringency of the current 

dynamometer-based emission standards or the costs of compliance. Based on 

consultations with manufacturers, EPA has decided to require that all HDGEs be 

certified on Tier 3 fuel by the 2022MY.366 To provide flexibility for very unique 

applications or circumstances, EPA will allow up to five percent of a 

manufacturer’s dynamometer-certified HDGE sales in any given model year to be 

certified using Tier 2 certification fuel. This flexibility is limited to certification 

based on carryover data beginning in the 2022MY. 

Second, as discussed in Section IV.F.5 for light-duty vehicles, we are 

committed to the principle of ensuring that any change in test fuel for heavy-duty 

gasoline vehicles/engines will not affect the stringency of either the fuel 

consumption or GHG emissions standards. As part of the separate rulemaking 

discussed in Section IV.F.5, we expect to establish the appropriate test procedure 

adjustment for HD engine fuel consumption standards and to determine the need for 

any test procedure adjustment for GHG emissions standards based on the change in 

certification test fuels. 

Third, to simplify the evaporative emission regulations for HDGVs and to 

bring them more in line with the current structure of the product offerings in this 

sector, we are finalizing provisions to permit evaporative emissions certification by

 

365 EPA also sought comment on whether to require HDGVs to use Tier 3 emissions test fuel for 

evaporative emissions standards even if we did not adopt the proposed Tier 3 evaporative emission 

standards and whether to allow Class 4 and above HDGVs to earn allowances or credits if EPA did 

not adopt the Tier 3 standards for these vehicles. These have been superseded by our decision to 

apply the Tier 3 evaporative emission standards to all HDGVs as described above. 

366 Passavant, G. (September 2013). EPA and General Motors Meeting on Issues Related to Tier 3 

NPRM and (September 2013). EPA and Ford Meeting on Issues Related to Tier 3 NPRM. 

Memorandums to the docket.
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engineering analysis for vehicles above 14,000 lbs GVWR (instead of above 26,000 

lbs GVWR as permitted in the existing regulations). We are also finalizing 

regulatory language to clarify how these provisions are to be implemented. This 

applies to the hot soak plus diurnal, running loss, and canister bleed standards. 

These HDGVs will remain subject to the emission standards when tested using the 

specified procedures. This is the same cut point allowed by CARB and will allow 

for one certification method. Even though it was supported by one commenter, we 

are not including specific provisions for design-based certification for HDGVs over 

14,000 lbs GVWR. EPA believes that the option to certify using engineering 

analysis and data serves the same purpose.

Fourth, we are finalizing a revised description of evaporative emission 

families that does not reference sealing methods for carburetors or air cleaners as 

this technology is now obsolete for HDGEs.

Fifth, EPA is finalizing regulatory language permitting HDGVs over 14,000 

lbs GVWR to be grouped with those between 10,001 and 14,000 lbs GVWR for 

purposes of complying with evaporative and refueling emission control standards 

and related provisions. In these cases, we require these HDGVs to meet all the 

requirements applicable to the group in which they are being included (e.g., useful 

life, OBD, etc.).

Finally, the regulations at 40 CFR part 86, subpart M, describe how to test 

heavy-duty vehicles above 14,000 lbs GVWR to demonstrate compliance with 

evaporative emission standards. Most of these provisions are identical to those that 

apply under 40 CFR part 86, subpart B. We are eliminating subpart M and 

replacing it with a simple instruction to test these heavy-duty vehicles using the 

procedures of subpart B, with a small number of appropriate modifications noted as 

exceptions to the light-duty test procedures. Relying on references to subpart B 

instead of largely copying them into subpart M eliminates many pages of 

unnecessary regulatory text and makes it easier to maintain a consistent set of 

requirements. Changing a provision in subpart B in the future will automatically

apply for evaporative testing of both light-duty and heavy-duty vehicles unless 

otherwise provided in the particular rulemaking. 

In response to comments received, we are specifying that heavy-duty 

vehicles above 14,000 lbs GVWR must use the same drive schedules and test fuels 

that apply for light-duty vehicles. Subpart M already allows light-duty drive 

schedules and certification test fuels as an alternative to using those for heavy-duty 

vehicles, and most if not all manufacturers of these vehicles already use the lightduty drive schedules, which facilitates testing simplicity and coordination of design 

parameters with light-duty vehicles. The heavy-duty drive schedule generally

involves less driving, which makes this the more stringent test option for designing 

purge. Omitting this more stringent option therefore does not change the effective 

stringency of the applicable standards. 
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With these changes from the proposed rule, there are only two aspects of 

testing that are different for heavy-duty vehicles above 14,000 lbs GVWR. First, 

the regulations specify that the exhaust emission measurements are not required for 

the driving portion of the test between canister pre-conditioning and diurnal testing. 

Exhaust emission standards in this vehicle size range apply based on engine testing 

only. Second, wider engine speed tolerances apply. This is captured in part 1066 

by specifying wider engine speed tolerances for any testing that does not require 

exhaust emission measurements since the greater allowance has no effect on 

emissions measurements. This applies, for example, for pre-conditioning drives for 

light-duty vehicles, and it also applies for pre-conditioning related to evaporative 

emissions of heavy-duty vehicles above 14,000 lbs GVWR.

There are some differences in the existing test provisions in subparts B and 

M that we are not preserving. Some of these differences arose from changes to 

subpart B that were inadvertently not carried over to subpart M. In other cases, 

there may have been an intentional distinction that no longer applies (such as 

provisions related to slippage on twin-roll dynamometers). Also, we are not 

retaining distinctions in Subpart M related to procedures for determining road load 

settings and for operating manual or automatic transmissions. Additional 

differences we are not preserving include gas divider specifications, SHED and 

dynamometer calibration procedures, and some provisions for alternative canister 

loading and vehicle pre-conditioning. We are also restoring the content of 

paragraphs §86.1235(b) through (i) related to dynamometer operating procedures, 

which were inadvertently removed in an earlier rulemaking. 

5. Evaporative Emission Requirements for FFVs

A flexible fuel vehicle (FFV) as defined in 40 CFR 86.1301-01 means any 

motor vehicle engineered and designed to be operated on a petroleum fuel and on a 

methanol or ethanol fuel or any mixture of the petroleum fuel and methanol or 

ethanol. Many manufacturers have one or more FFVs in their product offerings. 

These include many different LDV and LDT vehicle chassis styles including 

passenger cars, mini-vans, pick-ups, sport utility vehicles and even a few HDGVs.

The EPA regulations implementing the FFV provisions for ethanol FFVs, 

including those in 40 CFR 86.1811-04 and 86.1811-09, have been applied primarily

for FFVs capable of operating on gasoline/ethanol mixtures up to E85. As a matter 

of policy, EPA has not required certification testing for evaporative and refueling 

emissions on the full range of E0-E85 fuel blends, but instead has allowed the 

option to use a blend created when Tier 2 fuel (9 RVP E0) is splash blended with 

ethanol to a 10 percent gasoline/ethanol blend. This simulates what often occurs in 

the vehicle fuel tank when Tier 2 fuel (9 RVP E0) is dispensed into a tank 

containing mostly E85. This yields a blend which has a Reid vapor pressure of 

about 10 psi. Nearly all manufacturers have certified using this option. The 
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California ARB LEV III program has no special evaporative or refueling emission 

test fuel requirements for FFVs. 

In the Tier 3 NPRM, EPA proposed to revise the certification test fuel for 

evaporative emissions, to revise the hot soak plus diurnal emission standard, and to 

add a canister bleed emission standard and a leak standard. These standards apply to 

FFVs and non-FFVs. EPA proposed to revise the ethanol content of the 

certification test fuel for refueling emissions but did not otherwise propose to 

change the fuel vapor pressure, the level of the refueling emission standard or the 

test procedure. Furthermore, in the NPRM, EPA sought comment on leaving 

unchanged the basic approach to FFV certification test fuel for Tier 3 evaporative 

and refueling emissions, except that the certification test fuel would be 9 RVP E0 

splash blended with E15 such that the blend would have a 10 psi vapor pressure, 

i.e., the RVP of the evaporative emissions test fuel used by nearly all 

manufacturers. Manufacturers commented that the Tier 3 certification test fuel 

should be the same for FFVs and non-FFVs and that carryover should be permitted 

from Tier 2 to Tier 3. EPA met with several manufacturers to clarify their 

comments and to discuss issues affecting the evaporative and refueling emissions 

certification fuel for FFVs.367

For FFVs, EPA has several factors to consider for evaporative and refueling 

emission certification test fuel. First, EPA is finalizing a 9 RVP E10 certification 

test fuel for non-FFVs for evaporative and refueling emissions. This is consistent 

with our broader policy objective to allow the manufacturers to sell the same 

vehicles in all 50 states. Second, 10 psi RVP certification test fuel for the Tier 3 

evaporative emission standards for FFVs could result in more evaporative emission 

reductions than a 9 psi RVP test fuel, but this would be counter to the broader 

policy objective regarding a national program since CARB has no separate FFV 

evaporative emission standards and likely would affect the stringency of the final 

evaporative emission standards. Specifically, finalizing 10 psi RVP certification 

test fuel for the Tier 3 evaporative emission standards as applied to FFVs would 

increase the stringency of the evaporative emission standards for FFVs both 

compared to the Tier 3 evaporative emission standards with 9 psi RVP test fuel for 

non-FFVs and compared to the Tier 2/MSAT evaporative emission standards with 

10 psi RVP test fuel for FFVs. Third, we are not changing the level of the refueling 

emission standard (though we are adding ethanol to the test fuel and extending 

ORVR to complete Class 3 HDGVs) and we did not examine how a potential 

change from the existing 10 psi RVP test fuel for FFV refueling would affect in-use 

emission reductions or the stringency of the refueling standard for FFVs. A change 

in the test fuel vapor pressure likely would likely lead to a change in the stringency

 

367 Passavant, G. (September, 2013). EPA, GM, Ford, and Chrysler Meeting on Tier 3 Certification 

Fuel for Evaporative and Refueling Emission Standards for FFVs. Memorandum to the docket.
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of the refueling emission standard as they are now applied to FFVs. Retaining the 

current requirements for refueling emissions for FFVs does not affect the national 

program since CARB currently follows Federal Test Procedures and test fuels for 

ORVR. 

Balancing all of these factors, EPA is adopting a bifurcated scheme for 

evaporative and refueling emission certification for Tier 3. Evaporative emission 

requirements for the hot soak plus diurnal, canister bleed, running loss, spit back, 

and leak standards will be based on Tier 3 certification fuel (9 RVP E10) for FFVs. 

This will permit reciprocity between the LEVIII and Tier 3 evaporative emission 

standards programs and subject the manufacturers to only one set of evaporative 

emission tests for FFVs and non-FFVs. However, for the refueling emission 

standard, EPA is retaining the 10 psi certification test fuel requirement for FFVs 

because the worst case in-use RVP conditions when E0 and E85 are commingled 

will still be possible. In current systems, the fuel vapor pressure in the refueling 

emission test drives the total gasoline working capacity of the activated carbon 

canister that is necessary in the integrated evaporative/refueling control system. 

Although a 10 psi RVP certification fuel for evaporative emissions control could be 

viewed as more stringent, we believe that keeping the fuel vapor pressure at 10 psi 

in the refueling test, which is what was proposed for comment, will help to assure 

that the in-use emission reduction benefits of current evaporative systems on FFVs 

are retained. We expect that total canister gasoline working capacities will still be 

driven by the 10 psi RVP fuel used in the refueling test and therefore the higher inuse RVP conditions which impact evaporative emissions will still be addressed. 

EPA is specifying a 10 RVP E10 test fuel specification for FFV refueling 

emissions certification. However, as a compliance alternative EPA will continue to 

permit certification based on in vehicle fuel tank blending of two different fuels 

(i.e., vehicle fuel tank filled to 10 percent of capacity with E85 and then refueled to 

at least 95 percent of capacity with (9 RVP E0). Either of these approaches will also 

meet CARB certification test fuel requirements as the test fuel vapor pressure 

would be higher than with EPA’s 9 RVP E10 or CARB’s 7 RVP E10 test fuel. In 

addition, we are not changing existing requirements that all IUVP testing for 

evaporative and refueling tests are done on the non-FFV fuel (i.e., Tier 2 IUVP 

vehicles are tested on 9 RVP E0 and Tier 3 IUVP vehicles are tested on 9 RVP E10.

In their comments on the Tier 3 NPRM, manufacturers asked that EPA 

allow carryover of certification emission data from Tier 2 to Tier 3. Since the 

regulatory approach for refueling emissions is basically the same as what is 

currently being used by the manufacturers, we believe there should be opportunity

for carryover of refueling emission data under the current regulatory program. 

Manufacturers also expressed concern that the refueling emission standard would 

require them to keep a 10 RVP E10 or 9 RVP E0 test fuel solely for refueling 

emission standard certification purposes. To help address this concern, in 

certification testing, EPA would consider approving other refueling test fuel blends 
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with 10 percent ethanol and 10 psi such as a refueling event where a tank is filled 

initially with 10 percent E85 and during refueling test is filled with 90 percent 9 

RVP E0. EPA would also permit manufacturers the option to seek EPA approval to 

certify by attestation using alternative procedures or through engineering analysis 

based on similar evaporative/refueling emission system configurations and emission 

test results and data on similar vehicles showing that the vehicle could pass the 

refueling emission standard and meet the requirements in use on 10 psi RVP E10 

fuel. They would remain subject to confirmatory testing on 10 RVP E10. Both of 

these options could only be implemented with approval of the Administrator. 

6. Test Procedures and Certification Test Fuel 

a. Review and Update of Testing Requirements

EPA adopted the current test requirements for controlling evaporative 

emissions in 1993.368 Those changes included: (1) diurnal testing based on heating 

and cooling the ambient air in the SHED369 instead of forcing fuel temperatures 

through a specified temperature excursion; (2) repeated 24-hour diurnal 

measurements to capture both permeation and diurnal emissions; (3) hightemperature hot soak testing; (4) high-temperature running-loss measurements with 

a separate standard, including controlled fuel temperatures according to a fueltemperature profile developed for the vehicle; and (5) canister preconditioning to 

ensure that vehicles could effectively create canister capacity to prepare for several 

days of non-driving.

These test procedures are generally referred to as “enhanced evap” testing. 

EPA adopted these “enhanced evap” test procedures in coordination with CARB. 

The test requirements include two separate test sequences to demonstrate the 

effectiveness of evaporative emission controls. The “2-day sequence” involves 

canister loading to two-gram breakthrough, followed by driving for the exhaust test 

(about 31 minutes), a hot soak test, and two days of cycled ambient temperatures. 

The “3-day sequence” involves canister loading with 50 percent more vapor than 

needed to reach breakthrough, followed by driving for the exhaust test, driving for 

the running loss test (about 97 minutes total), a high-temperature hot-soak test, and 

three days of cycled ambient temperature.

The 2-day sequence was intended primarily to insure a purge strategy which 

would create enough canister capacity to capture two days of diurnal emissions 

after limited driving. The two-day measurement period is also effective for 

requiring control of permeation and other fugitive emissions. The 3-day sequence 

 

368 58 FR 16002 (March 24, 1993).

369 SHED is the Federal Register acronym for sealed housing for evaporative determination. The 

SHED is the enclosure in which the evaporative emissions are captured before measurement.
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was intended to establish a design benchmark for achieving adequate canister 

storage capacity to allow for several days of parking on hot summer days, in 

addition to requiring vehicle designs that prevent emissions during hightemperature driving and shutdown conditions. 

After adopting these evaporative test procedures, we set new standards for 

refueling emissions control which called for onboard refueling vapor recovery

(ORVR).370 Manufacturers have typically designed their ORVR systems to be 

integrated with their evaporative controls, using a single canister and purge strategy

to manage all fuel vapors vented from the fuel tank. Due to the magnitude of the 

refueling emission load and the manner in which the load rates affect activated 

carbon capture efficiency, it has become clear that ORVR testing with these 

integrated systems serves as the benchmark for achieving adequate canister storage 

capacity. 

In the nearly 20 years since adopting these test procedures, manufacturers 

have made great strides in developing designs and technologies to manage canister 

loading and purging and to reduce permeation emissions. Except as discussed 

below, we are not changing the test procedures for demonstrating compliance with 

the Tier 3 emission standards. As described above, we are adopting a new standard 

based on measured values over a canister bleed test, and a fuel system rig test. 

These are intended to measure only fuel vapors which diffuse from the evaporative 

canister or permeate/leak from a fuel system. CARB developed these procedures as 

a means for setting standards that are not affected by nonfuel background 

emissions. The canister bleed test procedure is a variation of the established twoday test sequence. The canister is preconditioned by purging and loading to 

breakthrough, then attached to an appropriate test vehicle for driving over the duty

cycle for the exhaust test. The canister is then attached to a fuel tank for 

measurement. After a stabilization period, the tank and canister undergo two days 

of temperature cycling. Canister emissions are measured using a flame ionization 

detector (FID), with a conventional SHED approach or by collecting emissions in a 

bag and measuring the mass. Rather than repeating CARB’s regulations, we are 

incorporating those regulations by reference into the CFR.371 This will avoid the 

possibility of complications related to minor differences that may occur with 

separate test procedures. The fuel system rig test is a bench test where a complete 

 

370 59 FR 16262 (April 6, 1994). 

371 For a description of the canister bleed test procedure (BETP), see pp.III-51 to III-55 of 

http://www.arb.ca.gov/db/search/search_result.htm?cx=006180681887686055858%3Abew1c4wl8hc

&cof=FORID%3A11&q=BETP&siteurl=http%3A%2F%2Fwww.arb.ca.gov%2Fhomepage.htm

(last accessed on January 13, 2014).
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vehicle fuel system (without the vehicle chassis) is constructed in the SHED and 

evaluated over the 3-day cycle in both a “wet” and “dry” state.372

CARB adopted the fuel system “rig test” as an optional approach to 

demonstrate control of evaporative emissions without the effects of the nonfuel 

hydrocarbon emissions that are seen in testing the whole vehicle in the SHED. We 

generally expect manufacturers to comply with the EPA requirements which 

include the canister bleed test and emission standard instead of CARB LEV III 

Option 1 which includes the rig test and emission standard. However, since we are 

accepting PZEV zero evap and CARB LEV III Option 1 certifications for the 2017-

2018MYs and 2017-2021 MYs, respectively, we are also incorporating by reference 

CARB’s rig test into the CFR to accommodate those manufacturers that do in fact 

rely on this approach.

Also, as discussed further below, we are adopting a new leak test procedure 

which will be used to measure leak rates for the leak standard. The leak test 

standard test procedure is contained in the regulatory text. 

Manufacturers have raised a pair of related concerns regarding the current 

test procedures. First, hybrid vehicles and new engine designs for meeting fuel 

economy standards and CO2 emission standards increase the challenge of 

maintaining an adequate purge volume to prepare vehicles for the diurnal test. For 

hybrid vehicles this is related to the amount of time the engine is running. For other 

technologies this is related to the trend toward decreasing available vacuum in the 

intake manifold, which is the principal means of drawing purge air through the 

canister. Second, preconditioning the canister by loading to breakthrough serves as 

a disincentive for some control strategies that might otherwise be effective at 

reducing emissions, such as designs involving greater canister capacity or better 

containment of fuel vapors inside the fuel tank. In addition, we have learned from 

studying in-use emissions and in-use driving behaviors and usage patterns that it is 

not uncommon for vehicles to go for an extended period with little or no 

opportunity to purge the canister.

In the NPRM, we requested comment on an optional adjustment to the test 

procedure intended to address these three concerns. In this alternative, for designs 

involving pressurized tanks, manufacturers would determine an alternative vapor 

load to precondition the canister before the exhaust test. If, for example, a fuel 

system is designed to stay sealed up to 1 psi and to vent vapors to the canister if 

rising temperatures trigger a pressure-relief valve, the manufacturer could quantify

the actual vapor load to the canister during three consecutive days of cycling 

 

372 See http:www.arb.ca.gov/msprog/macs/mac0503/mac0503.pdf for a description of the rig test 

standard and test procedure (last accessed on January 13, 2014).
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through diurnal test temperatures. This three-day vapor load would be the amount 

of fuel vapor used to precondition the canister (loaded at the established rate of 15 

grams per hour). This canister loading may also involve butane instead of fuel 

vapor, but we would likely require a greater mass of butane to account for the fact 

that it is easier to remove the butane from the activated carbon in the canister. This 

approach would be flexible to accommodate any design target for pressurizing fuel 

tanks. Canister preconditioning for the ORVR test (for integrated and 

nonintegrated systems) would remain unchanged. EPA sees merit in further 

consideration of such test procedure flexibilities, but auto manufacturers did not 

provide support these concepts in their comments and we are not adopting the 

proposed optional adjustment. 

b. Test Fuel for Certification

EPA is changing the certification test fuel specifications as described in 

Section IV.F. Here we discuss some implications for evaporative and refueling 

emissions testing beyond those discussed above for FFVs. We are revising the 

certification test fuel specification in conjunction with the Tier 3 standards, 

principally to include ethanol and reduce sulfur such that the test fuel better aligns 

with the current and projected in-use fuel. Although we received unsolicited 

comment asking that we set durability test fuel specifications for evaporative and 

refueling emission control systems to be the same as those for the certification test 

fuel (9 RVP E10 in this final rule), we are not changing durability fuel 

specifications in this rule other than to remove minimum sulfur content 

requirements. In particular, we are not changing the existing requirement that “any 

mileage accumulation method for evaporative emissions must employ gasoline fuel 

for the entire mileage accumulation period which contains ethanol in, at least, the 

highest concentration permissible in gasoline under federal law and that is 

commercially available in any state in the United States”. See §§ 86.1824-08(f)(1) 

and 86.113-04(a)(3)(i). EPA believes this is prudent policy to ensure that emission 

control systems are designed for the fuels with the potential to adversely affect 

durability and there is no reason to change the existing approach especially since 

E15 fuel is now legally permissible and commercially available for appropriate 

vehicles and there is potential for its market penetration to increase in the future. 

Any bench aging using E15 fuel must simulate the effects of alcohol in-use fuels on 

evaporative emission system components. 

Since there are already vehicles in the market which employ the technology 

needed to meet the new hot soak plus diurnal requirements, EPA is taking a flexible 

approach to the phase-in of the certification test fuel. This is summarized in Table 

IV-21. 

To accommodate vehicles already designed to meet CARB PZEV zero evap 

evaporative emission requirements, EPA’s phase-in provides that PZEV zero evap 

vehicles which qualify for carryover can use CARB Phase 2 fuel for evaporative 
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emissions (hot soak plus diurnal and running loss standards) and rig test 

certification for MYs 2015-2019. For CARB PZEV zero evap vehicles, high 

altitude, refueling, and spit back standard certification may use either EPA Tier 2 or 

Tier 3 fuel in MYs 2015-2019. In the 2018 and later MYs they must use Tier 3 test 

fuel for the leak standard. Beginning in the 2017 MY, the use of PZEV zero evap 

data is limited to carryover of data from 2015 or 2016 MY certifications. 

Those using CARB LEVIII Option 1 can use CARB Phase 3 fuel for 

evaporative emissions (hot soak plus diurnal and running loss standards) and rig test 

certification for MYs 2015-2021. For CARB Option 1, high altitude, refueling, 

and spit back standard certification must may use Tier 2 or Tier 3 fuel in MYs 

2015-2016 but in the 2017 and later MYs all LEV III option 1 certifications for the 

high altitude, refueling, spit back, and leak standards must use EPA Tier 3 fuel. 

CARB LEV III Option 2 evaporative emission vehicles may use CARB 

Phase 3 fuel to meet evaporative (hot soak plus diurnal and running loss standards) 

and canister bleed standards beginning in 2015MY and following. High altitude, 

refueling, and spit back may use Tier 2 or Tier 3 fuel in model years 2015 and 2016. 

For 2017 and later model years CARB LEV III option 2 evaporative families must 

use Tier 3 test fuel for high altitude, refueling, spit back, and leak standard 

certifications. 

Tier 3 evaporative emission vehicles must use Tier 3 fuel to meet

evaporative emission (hot soak plus diurnal and running loss standards), high 

altitude, canister bleed, and refueling/spit back emission standards beginning in the 

2015MY and following. Beginning in the 2018 MY, Tier 3 vehicles must use Tier 3 

emission test fuel to demonstrate compliance with the leak standard 

requirements.373

When the program is fully phased-in, any Tier 3 evaporative emission 

certification will have to use Tier 3 certification test fuel and test procedures or 

CARB equivalent test procedures and fuels. This could be done as early as the 

2015 MY and will be required for all vehicle models by the 2022 MY.374 As 

indicated above and in Table IV-21, we are further applying the new test fuel at the 

same time to ORVR testing. Therefore, beginning in the 2017 MY if manufacturers 

do any new testing to demonstrate compliance with the Tier 3 evaporative emission 

standards (using Tier 3 or LEV III fuel), they will need to submit test data to 

demonstrate compliance with the refueling emission standards using the new 

 

373 This provision applies in 2017 MY for vehicles meeting the Tier 3 requirements using the 20/20 

option and does not apply to HDGVs with a GVWR greater than 14,000 lbs. Incomplete HDGVs 

have until the 2022 MY to meet the spit back standard. 

374 The only exception here would be if a vehicle uses allowances in the 2022 model year to meet the 

Tier 3 evaporative emission requirements.
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certification test fuel as well as the leak (when applicable), spit back, canister 

bleed, running loss, and high altitude emission standards. Any family that is not yet 

captured within the Tier 3 phase-in percentage may remain on Tier 2 certification 

fuel through the 2021 MY. By the 2022 MY all evaporative and refueling 

emission certifications will have to be on EPA test procedures and certification 

fuels or CARB equivalents as identified in the regulations. Policies regarding test 

procedures and test fuels for EPA confirmatory and other post certification testing 

are discussed in Section IV.C.6.e below. 

Finally, we are including provisions to allow any vehicle certified to the 

refueling spit back standard separately (mostly incomplete HDGVs)to continue to 

do so using Tier 2 current certification fuel until the 2022 MY even if its 

evaporative emissions are certified on Tier 3 certification fuel. This is reasonable 

since the fill quality of the vehicle and eliminating spit back are not necessarily

related to the ethanol or sulfur content of the gasoline. The manufacturers must 

meet this requirement through testing, as the engineering evaluation flexibility

available for HDGVs over 14,000 lbs GVWR does not apply to this standard.

c. Correction for Ethanol Portion of the SHED Measurement

Another issue related to adding ethanol to the certification test fuel relates 

to the emission measurement in the SHED. Emissions are detected by flame 

ionization detectors (FID), which are less responsive to ethanol than gasoline. This 

effect causes under-reporting from the ethanol portion of the fuel vapor. Fuelrelated emissions from the vehicle may be slightly more weighted toward ethanol 

than gasoline, depending on how the different fuel constituents permeate through 

various fuel-system materials, how they evaporate from the bulk fuel in the tank at 

varying temperatures, and how they adsorb onto and desorb from the activated 

carbon in the canister. We proposed to address this issue by the use of a prescribed 

correction factor. Under this approach manufacturers would simply multiply their 

SHED measurement results by a fixed value to adjust upward for the difference in 

the FID response to ethanol. Data available to EPA at the time of the NPRM 

suggested that a value of approximately 1.1 would be appropriate for E15.375 For 

an E10 certification fuel, California ARB finalized a value of 1.08. 

In their comments, the manufacturers supported the use of a correction 

factor, but stipulated that the value put forth by EPA was too large and they should 

be given the option to measure the ethanol fraction of the vapor in the SHED 

through procedures and instrumental approaches prescribed in the regulations (see 

40 CFR1065.269, 1065.369, and 1065.805) instead of using a fixed correction 

value. Two manufacturers provided data based on testing with E10 test fuel which 

 

375

 Moulis, C. (2012, January). SHED FID Responses for Ethanol. Memorandum to the docket. 
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generally showed lower ethanol fractions than represented by the 1.1 value 

proposed by EPA for hot soak plus diurnal emissions, and uniformly showed very 

low ethanol fractions for refueling measurements.376

EPA has reviewed the data provided by the manufacturers and has 

considered their comment that they should be given the option to measure the 

ethanol fraction and adjust the SHED results rather than be required to use a fixed 

correction factor. Based on these considerations, EPA is establishing the following 

approach with regard to ethanol corrections. First, EPA will permit measurement or 

the use of a fixed correction factor on an evaporative family by evaporative family

basis. However, once the manufacturer selects an approach for any given 

evaporative family, that approach must be used in all subsequent testing of all 

vehicles certified using that data including carry over. For example, if a 

manufacturer chooses to measure the ethanol fraction for purposes of certification 

of a test group in a given model year, that same method must be used in any

manufacturer confirmatory testing as well as IUVP or IUCP testing of all vehicles 

in that test group. Alternatively, if a manufacturer uses the fixed correction factor 

in certification it must also use it for all evaporative emission tests covered by the 

requirement for a given test group and for all follow on testing. Second, the 

decision on measurement or correction factor must be uniform on a test group basis 

for all evaporative emission standards covered by the correction requirement. In 

this case this includes hot soak, diurnal, high altitude, running loss, and rig test 

measurements. Third, in terms of a fixed correction factor, EPA believes that the 

1.08 value adopted by California is consistent with the data and is specifying that 

value for hot soak plus diurnal (low and high altitude), running loss, and rig test 

measurement corrections for any testing conducted with 10 percent ethanol. Based 

on the data provided by the manufacturers, EPA is not requiring a fixed correction 

value or measurement for refueling, spit back, or canister bleed measurements for 

testing conducted with 10 percent ethanol. This aligns with the expectation that 

ethanol concentrations will be very low with FID-based measurements and that 

mass-based measurements will capture any ethanol adequately without a need for 

correction. Finally, EPA will use the method selected by the manufacturer in any 

confirmatory or surveillance testing. However, since corrections will always be 

zero or greater, no correction is needed to make a failure determination if the FID 

value exceeds the emission standard or FEL. With regard to the 1.08, EPA remains 

open to future revisions to this value, in coordination with CARB, if a fuller data set 

representative of various vehicle models, SHED FID ethanol response values, FID 

designs (analog vs. digital), ethanol calculation approaches (photo acoustic and 

impinger), and test sites demonstrates that a different value would be technically

 

376 Passavant, G. (2013, October). Manufacturer Data on Ethanol Measurements in the SHED. 

Memorandum to the docket.
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appropriate and adequately conservative relative to the direct measurement methods 

permitted in 40CFR1065.

 For higher ethanol blends (such as E85), the regulation already specifies 

measurement and calculation procedures to adjust for this effect. We are not 

making any changes to these procedures.

d. Vehicle Preconditioning for Nonfuel Hydrocarbon Emissions for the Tier 

3 Evaporative Emission Standards

The Tier 3 hot soak plus diurnal, leak, and canister bleed emission standards 

taken together are expected to bring about the widespread use of technology which 

effectively eliminates fuel vapor emissions. The fuel rig, canister bleed, and leak 

standards are not influenced by nonfuel hydrocarbon emissions from the vehicle. 

Nonfuel hydrocarbon emissions from the vehicle are measured as part of SHED 

emission testing, and are indistinguishable from fuel hydrocarbons when a FID is 

used to measure the concentration. The level of these nonfuel hydrocarbon 

emissions vary by vehicle and component design and material. These emissions 

arise from paint, adhesives, plastics, fuel/vapor lines, tires, and other rubber or 

polymer components and are generally greater with larger size vehicles. These 

nonfuel hydrocarbon emissions are usually highest with newly manufactured 

vehicles and decrease relatively quickly over time. 

Currently, manufacturers normally conduct some preconditioning to reduce 

or eliminate the effects of these nonfuel hydrocarbon emissions on evaporative

emissions measurements in the SHED. In the past, this practice has not been 

addressed through regulatory provisions. However, given the stringent level of the 

Tier 3 hot soak plus diurnal evaporative emission standards, and that nonfuel 

hydrocarbon emissions are expected to be a significant portion of the hydrocarbon 

emissions measured in the SHED, EPA believes that some sort of preconditioning 

before certification testing is appropriate and that a regulatory provision addressing 

this practice is warranted. Providing some recognition of and allowance for this 

practice will help to create the proper balance between necessary and proper 

preconditioning to address high nonfuel hydrocarbon emissions and excessive 

preconditioning which could undermine the intent of the hot soak plus diurnal 

emission standard (~ 50 mg or less of fuel evaporative emissions). EPA believes 

the goal of evaporative emissions preconditioning should be to get nonfuel 

hydrocarbon emissions to what we call vehicle background levels. A working 

definition of vehicle background level might be the level which will occur naturally

twelve months after production. A provision in the regulations which addresses 

preconditioning reduces ambiguity for the manufacturers and could reduce or 

eliminate any uncertainty in the true meaning of certification test results. 

Manufacturer activity with regard to preconditioning often involves two 

practices. First, manufacturers in some cases “bake” their test vehicles at 
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temperatures of 50 °C or higher for periods of up to ten or more days to accelerate 

the off-gassing of these nonfuel hydrocarbon emissions before testing is conducted. 

While this practice is common, there is no standardized method or protocol for this 

preconditioning prior to new vehicle certification testing. For example, some 

manufacturers bake for a set period of time in a climate chamber while others bake 

in the climate chamber and periodically measure nonfuel background in a SHED 

until an acceptable or stable level of nonfuel hydrocarbon emissions is achieved. 

Second, manufacturers often remove, modify, or clean certain components which 

are the largest source of nonfuel hydrocarbon emissions. Preconditioning could 

also include measures to eliminate minor fuel drips, spills, or other fuel remnants 

which occur as a result of vehicle preparation for testing.

We are not specifying standardized pre-conditioning practices or protocols 

with regard to addressing nonfuel hydrocarbon emissions before evaporative 

emission certification testing. However, we are finalizing general provisions in four 

areas. First, we specify in the regulations that preconditioning for the purpose of 

addressing nonfuel hydrocarbon emissions is permitted. Second, we specify that 

any preconditioning is voluntary. Third, we specify that if preconditioning is 

conducted, the details must be specified to EPA before certification testing, (i.e., at 

the time of the pre-certification planning meeting). The goal of this preconditioning 

should be to get nonfuel hydrocarbon emissions to vehicle background levels as 

discussed above. The specifics to be discussed with EPA could include details on 

vehicle baking practices such the temperature and time duration in the climate 

chamber and practices conducted as an alternative or complement to vehicle baking 

such as installing used tires (drive and spare) on certification vehicles, and allowing 

the windshield washer tank to be filled only with water. EPA’s goal in these 

discussions is to gain certainty that manufacturers are not preconditioning vehicles 

so severely that they create a level of nonfuel hydrocarbons that is artificially low 

and would not occur in use and thereby creating a false additional compliance 

margin for fuel hydrocarbons in the certification test. Fourth, except as discussed 

below we are providing in the regulations that no pre-conditioning is permitted for 

testing of any vehicle aged more than twelve months from its date of manufacture. 

This restriction for vehicles older than 12 months includes certification,

confirmatory and in-use testing for any vehicle certified to the Tier 3 evaporative 

emission standards. For these vehicles, nonfuel hydrocarbon emissions will

presumably be reduced to a stable level due to natural off gassing which begins 

after the vehicle is manufactured. Emissions from any replacement parts or other 

vehicle maintenance will presumably be encompassed within the margin below the 

standard created by this natural off-gassing.

 EPA received several comments concerning the proposed restriction on 

pre-conditioning of vehicles older than 12 months from the date of manufacture. 

The Alliance of Automobile Manufacturers and the Association of Global 

Automakers asked that baking be permitted if such a vehicle is found to have 

identifiable contamination due to causes such as a fuel spill, refrigerant leak, or 
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washer fluid leak and that the manufacturer be given the option to age the tires (tires 

only) from any vehicle where the tires are less than twelve months from 

manufacture as indicated on the sidewall. CARB asked that EPA only allow the use 

of an aged spare tire in any testing and not spare tire removal. EPA generally

agrees with these commenters and is finalizing provisions for limited flexibility

subject to EPA approval. Under these provisions manufacturers may be permitted to 

clean any spills or leaks but not to bake the entire vehicle. Baking of tires less than 

12 months old may also be permitted with EPA prior approval. Vehicles must be 

tested with a spare tire in place since emissions from the spare tire were considered 

as the standard was developed. Manufacturers may exchange a new spare tire for 

one that is baked or aged. Finally, one manufacturer indicated that there may be 

circumstances where the base chassis for a certification vehicle was used in 

previous certification but that this base chassis was modified for a new model year 

and cleaned, reconfigured, and recertified with new components which affect 

background emissions.377 While EPA believes this would be a rare occurrence, 

regulatory provisions in this rule allow EPA to approve additional pre-conditioning 

for vehicles in this situation upon manufacturer request and justification.

e. Reciprocity with CARB

Over the past 15 years EPA’s “enhanced evap” test procedures have been 

based on testing with 9 pound per square inch (psi) RVP gasoline with test 

temperatures representing a summer day with peak temperatures of about 96 °F. 

CARB adopted the same basic procedures, but specified that testing should occur 

with 7 psi RVP gasoline at temperatures of up to 105 °F. EPA and CARB agreed 

that certification could be based on testing with either EPA or CARB conditions 

and that these provided equivalent stringency for purposes of evaporative control 

system design. However, the provision allowing for this equivalence of test data 

preserved EPA’s ability to also test with either EPA or CARB temperature

conditions and related test fuels. CARB always specified EPA test conditions for 

refueling as they were deemed worst case. CARB recently changed their 

certification test fuel to a 7 RVP gasoline with 10 percent ethanol and as discussed 

in Section IV.F, we are changing the Federal certification test fuel specification to a 

9 RVP gasoline with 10 percent ethanol.

 During the development of this FRM we carefully considered the practice 

of CARB/EPA reciprocity with regard to certification test fuels, hot soak plus 

diurnal test procedures, running loss test procedures, and emission test results when 

it comes to evaporative emissions certification. Based on these considerations and 

the alignment of the ethanol content for the EPA and CARB certification fuels, we 

 

377 See public comment EPA-HQ-OAR-2011-0135-4299 and Passavant, G. (2013, October). VW Email to EPA Regarding Vehicle Preconditioning. Memorandum to the docket.
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have decided to retain our current approach with regard to CARB/EPA reciprocity

for evaporative and refueling emissions. EPA and CARB have agreed to continue 

accepting emission test data on each other’s test fuels and temperature conditions 

for certification such that a uniform national program for certification test fuel will 

be able to exist. For model years during the evaporative emissions standard phasein discussed above (ending after the 2021 MY), EPA will conduct any post 

certification testing on any vehicle in the Tier 3 program manufactured in the 2015-

2021 MYs using the fuel and temperatures used by the manufacturer for 

certification. This approach covers families certified using carry over PZEV 

evaporative emissions data (through the 2019 MY) and LEV III Option 1 

certifications (through the 2021MY). Our program flexibility in the area of test 

fuels for hot soak plus diurnal, running loss and SHED rig/canister bleed emission 

standards is summarized in Table IV-24. After the 2021model year, EPA will 

retain the option to test on either set of temperatures/fuels. This applies to all 

evaporative emission standards (hot soak plus diurnal, running loss, and canister 

bleed). For the other emission standards (refueling, leak, spit back, and high 

altitude hot soak plus diurnal) EPA will use the test fuel used by the manufacturer 

through the 2019 model year. For the 2020 model year and later we may use Tier 3 

fuel or California Phase 3 if its use is permitted for certification. Please refer to the 

regulatory text for specific provisions.

EPA will review all Tier 3 program evaporative emissions data. If the data 

shows that the EPA and CARB based test requirements give fully equivalent 

results, in the future we may revise our regulations so that a vehicle is always tested 

on the fuel used for its initial certification.

Table IV-24 Tier 3 Evaporative Emissions Program Options and Test Fuels

Vehicle 

Program

Start 

MY

Program 

Standards

Cert Fuel EPA test fuel for 

confirmatory, 

surveillance & IUVP

End MY

for Use in 

Tier 3

PZEV 

zero 

evap.

2015 Hot soak + 

diurnal, 

running 

loss & 

SHED rig

CA Ph. 2 Fuel used by the 

manufacturer

After 

2019MY

LEVIII 

Opt. 1

2015 Hot soak + 

diurnal, 

running 

loss & 

SHED rig

CA Ph. 3 CA Phase 3 through 2019 

MY, after EPA may use 

Tier 3 or CA Phase 3

After 

2021MY

LEV III 

Opt. 2

2015 Hot soak + 

diurnal, 

running 

CA Ph. 3 CA Phase 3 through 2019 

MY, after EPA may use 

Tier 3 or CA Phase 3

N/A
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loss & 

canister 

bleed

Tier 3 2015 Hot soak + 

diurnal, 

running 

loss & 

canister 

bleed

Tier 3 Tier 3 N/A

As shown in Table IV-21, to qualify as a Tier 3 vehicle for evaporative emission 

purposes vehicles must meet the hot soak + diurnal, high altitude, rig/canister

bleed, running loss, refueling, and spit back standards. The leak standard applies 

beginning in the 2018MY and the SHED rig/ canister bleed tests are program 

specific.

Generally, a vehicle test group using Tier 3 certification fuel and test 

procedures for meeting the various evaporative and refueling emission standards 

will qualify for inclusion in the Tier 3 evaporative emission standards phase-in. 

However, EPA recognizes that the California and federal evaporative emission 

standard programs are starting from different bases and that the transition 

provisions are different in some ways. For example, the EPA program starts in the 

2017 MY but after that has the same basic program construct as CARB in 2018. 

However, prior to the 2017 MY, CARB has a ZEV program provision which will 

continue to bring zero evap technology into the fleet before the 2017 MY and 

CARB also allows early LEV III Option 1 and Option 2 evaporative emission 

certifications. To capitalize on this technology and to facilitate transition, we are 

finalizing provisions that any CARB evaporative emission test data from MYs 2015 

and 2016 PZEV zero evap certifications (hot soak plus diurnal and running loss)

can be used in federal certification for those evaporative families through the 2019 

MY. Similarly, we are finalizing provisions that CARB LEV III Option 1 

certifications (hot soak plus diurnal and running loss) can be used in federal 

certification for those evaporative families through the 2021 MY. Assuming the 

vehicle test groups also meet the Tier 3 high altitude evaporative emission 

standards, the refueling emission standard, the spit back standard, and the leak 

standard when applicable, they could be included in the percentage phase-in 

calculations as Tier 3 vehicles. If the vehicles do not meet the Tier 3 evaporative 

emission requirements manufacturers could potentially sell them nationwide, but 

they could not be included as Tier 3 compliant vehicles in the percentage phase-in 

calculation. Table IV-21 provides a concise summary of the requirements a vehicle 

must meet to qualify as a Tier 3 vehicle during the program’s early, transition, and 

phase-in periods. 
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 EPA proposed a similar provision for a manufacturer who elects to use the 

CARB test procedures and test fuels to meet the refueling emission standard. 

However, no manufacturer indicated interest in their comments and we have 

decided not to include reciprocity for this provision in the Tier 3 program. While 

experimental data based on field bench testing suggests that the CARB test fuel 

RVP and dispensed temperature together would give the same results as the EPA 

test fuel RVP and dispensed temperature there are no vehicle test data in the record 

at this time. CARB has always accepted refueling and spit back certification on 

EPA test fuel and will continue to do so in the future. This provision would have 

added another layer of complexity to the program and was not necessary since the 

refueling and evaporative tests are done separately.

f. Evaporative and Refueling Emission Standards for Various Fuels

The evaporative and refueling emission standards apply in different ways to 

different fuels. First, with regard to the evaporative emission standards, Clean Air 

Act section 202(k) specifies that gasoline-fueled vehicles must be certified to 

evaporative emission standards. Section 202(a) authorizes EPA to establish 

evaporative emission standards for other fuels. Today evaporative emission 

standards apply to LDVs, LDTs, MDPVs, and HDVs fueled by gasoline methanol, 

ethanol, natural gas, and liquified petroleum gas (LPG). For the refueling emission 

standard the situation is quite different. Section 202(a)(6) of the Clean Air Act 

specifies that the refueling emission standards apply to all LDVs regardless of the 

fuel used. Section 202(a) of the Clean Air Act authorizes EPA to establish emission 

standards for other fuels and classes of vehicles. Prior to the Tier 3 final rule, the 

refueling emission standards applied to all vehicles less than 10,000 lbs GVWR 

regardless of the fuel used. 

In the NPRM, EPA requested comment on applying the refueling standards 

to all vehicles regardless of fuel used. This would include all volatile fuels.378 The 

evaporative standards apply today to all volatile fuels379 (except for diesel) and we 

asked for comment on explicitly including dedicated ethanol as well as fuel-cell 

vehicles, and electric vehicles. EPA also requested comment on applying the 

refueling and evaporative standards only to vehicles using volatile liquid fuels

instead of all volatile fuels. 

EPA received four comments on this issue. One commenter expressed the 

view that evaporative requirements should be expanded to apply to volatile liquid 

fuels plus liquified petroleum gas (LPG) and liquified natural gas (LNG) while the 

 

378 A volatile fuel is a volatile liquid fuel or any fuel that is a gas at atmospheric pressure; gasoline, 

methanol, ethanol, natural gas, and LPG are volatile fuels.

379 A volatile liquid fuel is a fuel that is liquid at atmospheric pressure and has a Reid Vapor Pressure 

higher than 2.0 pounds per square inch – gasoline, ethanol, and methanol.
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three other commenters did not see the need to apply the requirements to any

gaseous fueled vehicle or other vehicle using a non-volatile liquid fuel because 

these vehicle fuel systems are sealed and rarely vent during normal operation or 

never vent at all. 

As is discussed further in the Summary and Analysis of comments, based on 

the comments, the fuel properties, and current industry fuel system design practices, 

EPA has decided to retain the requirement that the evaporative and refueling 

emission standards apply to vehicles using any volatile fuel. For gaseous fueled 

vehicles (LPG and LNG/CNG vehicles), only the Tier 3 3-day hot soak plus diurnal 

and running loss standards apply. For the other volatile fuels all of the Tier 3 

evaporative emission standards apply. For the refueling emission standard the 

requirements apply to all complete vehicles less than 10,000 lbs GVWR regardless 

of the fuel used. This is not being changed, except that the requirement will not 

apply to diesel-powered LDTs and HDVs vehicles. For vehicles over 10,000 lbs 

GVWR, the refueling emission standards will apply only to complete vehicles. 

This includes LPG, CNG, LNG, and dedicated ethanol or methanol vehicles. While 

the test procedures for these standards would apply, EPA is including regulatory

provisions to permit manufacturers to certify based on related data, engineering 

analysis, and compliance with published consensus standards. We are not applying 

these requirements to electric or fuel cell vehicles.

For vehicles equal to or less than 8,500 lbs GVWR, the Tier 3 evaporative 

and refueling emission standards for alternative fuel vehicles apply to each vehicle 

of a vehicle evaporative/refueling family as the family is included in the 

manufacturer’s phase-in for the Tier 3 evaporative emission standards. For vehicles 

over 8,500 lbs GVWR, the application of the Tier 3 evaporative emission standards 

depends on the Job 1(first build) date for the vehicle evaporative family. If the Job 

1 date for a vehicle model is before the fourth anniversary date of the signature of 

the rule then the Tier 3 evaporative emission standards do not apply until the next 

model year. If the Job 1 date is after the fourth anniversary date, the Tier 3 

evaporative emission standards apply in that model year. This determines when the 

vehicle is to be included in the denominator of the percentage phase-in calculation. 

The refueling emission standard applies only to complete vehicles and we are 

applying the same phase-in requirements as for complete HDGVs. For complete 

vehicles between 10,000 and 14,000 lbs GVWR the refueling emission standard 

applies in the 2018 model year. For complete vehicles with a GVWR in excess of 

14,000 lbs GVWR, compliance is required in the 2022 model year. Finally, for all 

small businesses, the Tier 3 evaporative and refueling emission standards do not 

apply until the 2022 model year. 

g. Other Changes and Future Considerations

This rulemaking included consideration of several amendments or 

clarifications to existing requirements related to evaporative emissions. As part of 
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this process, EPA has concluded that the following provisions warrant adjustment, 

clarification, or correction: 

 Even though the evaporative emission standards in 40 CFR part 86 apply to 

the same engines and vehicles that must meet exhaust emission standards, 

we require a separate certificate for complying with evaporative and 

refueling emission standards. An important related point to note is that the 

evaporative and refueling emission standards always apply to the vehicle, 

while the exhaust emission standards may apply to either the engine or the 

vehicle. Since we plan to apply evaporative/refueling/leak standard and the 

recently adopted greenhouse gas standards to vehicle manufacturers, we 

believe it will be advantageous to have the regulations related to their 

certification requirements written together as much as possible to reduce 

burden and increase efficiency. Therefore, for 2015 and later model years, 

we are moving the emission standards and certification requirements for 

HDGVs from 40 CFR part 86 to the new 40 CFR part 1037, which was 

originally used for greenhouse gas standards for heavy-duty highway 

vehicles. This is not intended to change the requirements that apply to these 

vehicles, except as noted in this section. 

 Section 86.1810-01 contains specifications addressing whether diesel fuel 

vehicles can be waived from demonstrating compliance with the refueling 

emission standard through testing. In the existing regulation the potential for 

a waiver from testing depended on the diesel fuel having an RVP equal to or 

less than 1psi and the fuel tank having a temperature which does not exceed 

130°F. We have examined this provision and are withdrawing the fuel 

temperature limit specification. Short of fuel spillage in the SHED, EPA 

sees no likelihood that a diesel fueled vehicle with RVP less than 1 psi could 

fail the refueling emission standard even at fuel tank temperatures above 

130°F. This is due to the inherently low vapor pressure of diesel at these 

temperatures and the likelihood that vapor shrinkage conditions will occur 

in the fuel tank during refueling since the dispensed fuel will be much cooler 

than the tank fuel. 

 When adopting the most recent prior set of evaporative emission regulatory 

changes we did not carry through the changes applying evaporative 

emission standards to vehicles using methanol-fueled compression-ignition 

engines. This final rule corrects this oversight.

 We are finalizing provisions to address which standards apply when an 

auxiliary (nonroad) engine is installed in a motor vehicle, which is currently 

not directly addressed in the highway regulation. The approach requires

testing complete vehicles with any auxiliary engines (and the corresponding 

fuel-system components). Incomplete vehicles are to be tested without the 

auxiliary engines, but any such engines and the corresponding fuel-system 
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components will need to meet the standards that apply under our nonroad 

program as specified in 40 CFR part 1060.

 We are removing the option for secondary vehicle manufacturers to use a 

larger fuel tank capacity than is specified by the certifying manufacturer 

without re-certifying the vehicle. Secondary vehicle manufacturers needing 

a greater fuel tank capacity must either work with the certifying 

manufacturer to include the larger tank, or go through the effort to re-certify

the vehicle. This provision has not been used and is better handled as part 

of certification rather than managing a separate process. We are including

corresponding changes to the emission control information label.

 We are revising the provisions for setting the vehicle air conditioning 

controls during the running loss portion of the evaporative emissions test 

cycle to simply reference the specifications for exhaust emission testing 

described in 40 CFR part 1066. This allows test labs to use a uniform set of 

test procedures for setting up test vehicles. This change is expected to have 

no effect on the stringency of the running loss test.

 EPA regulations at §86.1824-01 permit manufacturers to develop their fulluseful life deterioration factors for evaporative and refueling emission 

standards based on the use of good engineering judgment. These factors are 

additive in nature, and when added to the “undeteriorated low mileage” test 

value the sum must be less than the applicable emission standard or FEL. 

Manufacturers usually certify such that this summed value falls below the 

emission standard or FEL enough to provide a margin for in-use compliance 

and to address variability and other uncertainty. Regulations (at §86.1824-

08) require that evaporative emissions durability assessments must employ

gasoline fuel for the entire mileage accumulation period which contains 

ethanol in, at least, the highest concentration permissible in gasoline under 

federal law and that is commercially available in any state in the United 

States (currently E15). In their comments the Alliance of Automobile 

Manufacturers and the Association of Global Automakers asked to be able 

to use evaporative emissions deterioration factors from Tier 2/LEVII 

assessments even if the assessed or measured full life emission value used to 

determine the deterioration factor from the Tier 2/LEV II 2 testing is above 

the Tier 3/LEV III emission standard for the vehicle category of interest. 

(This situation, which is often referred to as line crossing, is not prohibited 

in the EPA regulation.) 380 Thus, EPA is permitting the use of this data but 

requires that: (1) the manufacturers use good engineering judgment in the 

 

380. Passavant, G. (December 2013) Background Information on Background Information: Carryover 

of Emissions Data and Line Crossing. Memorandum to the docket. 
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testing used to develop their deterioration factors and the assessment and 

application of this data in developing deterioration factors, (2) the 

manufacturers use the evaporative/refueling emissions test fuel as stipulated 

in the regulations for Tier 3, and (3) the addition of the deterioration factor 

to the low mileage test result does not result in an exceedance of the 

emission standard or the FEL cap for that category of vehicles.

D. Improvements to In-Use Performance of Fuel Vapor Control Systems 

1. Reasons for Adding a Leak Test Standard

As emission standards approach zero, as in the “zero evap” standards 

discussed above, in-use performance becomes critical for vehicles to meet the 

standards over their useful life periods and provide the expected emission 

reductions. Fuel vapor control system leaks are not a new problem, in fact it was 

one of the main reasons for replacing the canister method for assessing evaporative 

emissions with the enclosure (SHED test) method used today.

381

 However, as 

emission standards have become more stringent, test procedures have improved, 

and vehicle lifetimes have increased, any malfunction or deterioration in the system 

causes significant emissions increases. Even a small leak can cause large amounts 

of HC vapor. Therefore, the prevalence of leaks in the fleet can have a significant 

effect on the average evaporative emissions overall. 

As discussed in detail in the NPRM, recent laboratory and field data382 show 

very high emissions from vehicles with liquid/vapor leaks. Field studies have 

indicated approximately 10 percent of overall fleet have significantly elevated 

evaporative emissions. The studies show that this frequency increases as vehicles 

age. The Coordinating Research Council (CRC) E-77 programs randomly recruited 

sixteen vehicles and almost half had some type of leak. Emissions related to these 

leaks grew in magnitude over the course of the program which lasted a few years.

In addition, the EPA recently completed a test program to gather information on 

 

381 Rarick.T, “Evaporative Emission Enclosure (SHED) Procedure Analysis of Surveillance Program 

Data,” Evap 75-2, June 1975 and “Investigation and Assessment of Light-Duty Vehicle Evaporative 

Emission Sources and Control,” EPA -460/3-76-014, June, 1976.

382 CRC E-77 reports: Haskew, H., Liberty, T. (2008). Vehicle Evaporative Emission Mechanisms: 

A Pilot study, CRC Project E-77; Haskew, H., Liberty, T. (2010), Enhanced Evaporative Emission 

Vehicles (CRC E-77-2); Haskew, H., Liberty, T. (2010), Evaporative Emissions from In-Use 

Vehicles: Test Fleet Expansion (CRC E-77-2b); Haskew, H., Liberty, T. (2010), Study to Determine 

Evaporative Emission Breakdown, Including Permeation Effects and Diurnal Emissions Using E20 

Fuels on Aging Enhanced Evaporative Emissions Certified Vehicles, CRC E-77-2c; DeFries, T., 

Lindner, J., Kishan, S., Palacios, C. (2011), Investigation of Techniques for High Evaporative 

Emissions Vehicle Detection: Denver Summer 2008 Pilot Study at Lipan Street Station; DeFries, T., 

Palacios, C., Weatherby, M., Stanard, A., Kishan, S.(2013) Estimated Summer Hot-Soak 

Distributions for Denver’s Ken Caryl I/M Station Fleet.
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running loss emissions with implanted leaks of varying sizes, locations and fuel 

volatility.

383 Data from this study is not included in the modeling analysis for this 

final rule, but the results show that there are significant emissions from leaks while 

driving as the fuel tank temperature rises. Therefore the reductions from the future 

prevention of leaks will be larger than our current estimates.These data led EPA to 

examine the OBD-based evaporative system leak data available from I/M programs 

from several states to more accurately gauge the rate of leaks above the 0.020” 

monitoring threshold met by most manufacturers as a result of CARB’s 2004 model 

year OBD II requirements.384. These are important data because even a vehicle with 

a fuel/evaporative system leak as small as 0.020” would be expected to fail the Tier 

3 evaporative emission standard in a SHED test and in fact emit 4- 5 times above 

the Tier 3 emission standard on a daily basis due to the number of vehicle trips per 

day.

We examined data for vehicles meeting CARB’s OBDII evaporative 

emission leak monitoring requirements as well as either the CARB/EPA enhanced 

evaporative emission or Tier2/LEV II evaporative emission standards. Since the 

data were gathered by the states under different protocols and time periods, the 

content of the data sets is not identical. To provide some degree of uniformity in 

our analysis, we examined the data for model years 2000 and later, but within each 

state we only looked at calendar years of data beginning after the initial state I/M 

exemption period had passed (2-6 calendar years depending on the state). Thus the 

analysis focused on I/M OBD information for calendar years 2004-2012.

Examined together, the data generally indicate the following. 

 For all our States analyzed, the trend lines show that between 2 – 4 percent 

of the vehicles entering the I/M program (at about 2 years old) have a “not 

ready” evaporative monitor. The percentage increased to between 8 – 11 

percent as the vehicle aged to 8 years old with a rate increase of 

approximately 1 percent per year as the vehicle ages.

 The model years and time periods analyzed for the four States shows

approximately 0.7-2.5 percent of vehicles overall with a “ready” evap 

monitor had one or more stored evap DTCs, indicating a potential 

evaporative emissions-related problem as defined in the OBD regulations.

 

383 Kishan, S., Sabisch, M., Stewart, J., Glinsky, G. (2014) Running Loss Testing with Implanted 

Leaks.

384 Weatherby, M., Sabisch, M., Kishan, S. (2014) Analysis of Evaporative On-Board Diagnostic 

(OBD) Readiness and DTCs Using I/M Data. Note: the data was presented in a docket memo for 

NPRM\ and is now part of a peer reviewed report.
Page 255 of 529

 A further review of the data shows that, overall, in the three States with an 

enforced OBD program approximately 0.7 – 1.6 percent of vehicles with a 

“ready” evap monitor had one or more stored evaporative emissions related 

DTCs. The fourth State, which does not enforce the OBD test, had a higher 

percentage (2.5 percent) of evap monitor “ready” vehicles that had stored 

evap related DTCs. 

 For the same model years and time periods analyzed for the three States 

with enforced OBD programs, EPA estimates about 0.5 percent of vehicles 

with a “ready” evap monitor evaluated at four years old in an I/M program 

had a stored DTC. This rate increased at a rate of about 0.15 percent per 

year and was about 1.1 percent for vehicles at 8 years old. For the fourth 

state, which does not enforce OBD evaporative results, EPA estimates about 

1.4 percent of vehicles evaluated at four years old had a stored DTC. This 

rate increased at a rate of about 0.5 percent per year and was about 3.5

percent for vehicles at 8 years old. 

 Analyzing each state’s data for specific evaporative DTCs, over 50 percent 

of all evaporative codes were for evaporative system leaks. The second 

most common category (15-20 percent) involved some sort of error in the 

operation of the purge flow control which could also contribute to 

evaporative leaks. 

 The monitor “ready” rates are relatively uniform for all States analyzed, but 

the percentage of evaporative emissions related MILs illuminated and the 

percentage of evaporative system leak related DTCs were larger in the 

fourth State. EPA believes this is the case because OBD is advisory only in 

this State’s I/M program, meaning that a vehicle could pass its I/M 

requirement with a MIL illuminated and not have to repair it.

In considering this information for the fleet as a whole, a few other factors 

must be considered. First, a vehicle can pass its I/M requirements (based on 

provisions of individual State I/M programs) with the evaporative emissions 

monitor “not ready”. Second, the vehicle can pass with a pending DTC. Third, it is 

not uncommon for vehicle repair related to an OBD MIL to occur just before I/M

visits. Based on factors such as these, the values presented above are likely to be 

conservative on a fleet average basis. Beyond this, as discussed in the NPRM, 

earlier research conducted by EPA and the state of Colorado indicated that OBD is 

not designed to catch every evaporative system leak and sometimes misses leaks it 

should have found but did not for various reasons (some determined and some 
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unknown).385 This suggests that overall leak prevalence is higher than indicated by 

the OBD data alone. 

Estimating a nationwide fleet average leak rate is possible with the limited 

data available if some informed assumptions are made. Only about 24.5 percent of 

vehicles in the U.S. are in I/M areas and of these only 20.8 percentage points (~4/5) 

are in areas which rely on OBD as part of the pass/fail protocol. There is at present 

no data on the prevalence of evaporative system leaks for vehicles in areas without 

I/M. However, based on these data it reasonable to assume that the rates in these 

areas are no less than for areas with I/M (where I/M mandates repair) and are likely 

similar to or larger than those for the one state analyzed where OBD is advisory

only. Under those assumptions, the average leak rate across the country is much 

higher than for I/M areas alone. For example, if one considers data from the eight 

year age point in the I/M data for states which require repair, the leak prevalence 

rate is about 1.4 percent and in the state where OBD is advisory it is 3.5 percent. 

Weighted by the fleet percentages given above, this indicates a leak rate of about 

3.0 percent in the fleet for the eight year age point. This is a conservative estimate 

based on historic evaporative I/M data386.

The propensity for leaks in the vehicle fleet has the potential to reduce the 

benefits of the Tier 3 evaporative emission standards substantially. If on any given 

day, as few as 3 percent of Tier 3 vehicles have a leak(s) of 0.020 inches or greater 

this will cause in-use emissions equivalent to essentially all of the projected 

emission reductions from the Tier 3 evaporative emission standards on that day.

387

 

The leak standard we are adopting will help technology to meet the Tier 3 

evaporative emission standards and to improve in use durability. These technology

measures (see Section IV.C.3) coupled with the upgrade to the OBD evaporative 

emissions certification and monitoring requirements to signal problems at smaller 

threshold diameters (discussed in Section IV. E below) and additions to the IUVP 

program focused on testing a larger sample of vehicles for fuel/evaporative system 

leaks in IUVP than for evaporative emission standards alone will help to ensure 

improved in-use performance of evaporative emission control systems.

Based on the above discussion, there needs to be an increased focus on 

evaporative emissions durability. Nevertheless, there is no question of the value of 

OBD leak monitoring for evaporative systems, especially when owners complete 

 

385 Eastern Research Group (2013) Evaluation of the Effectiveness of On-Board Diagnostic (OBD) 

Systems in Identifying Fuel Vapor Losses from Light-Duty Vehicles.

386 USEPA (2014), “Development of Evaporative Emissions Calculations for Tier 3 FRM” 

memorandum to the Tier 3 docket.

387 See EPA memorandum: “Initial Comparison of Emission Rates from Vehicles with Fuel/Vapor 

System Leaks to Tier 3 Evaporative Emission Reductions, December, 2013.” 
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needed repairs in response to the DTCs set. The I/M OBD statistics and associated

in-use leak values discussed above would be higher without OBD evaporative 

system leak monitoring. However, these data suggest that EPA OBD regulations in 

place for 2004 and later model year vehicles will not alone be sufficient to address 

concerns regarding the emission effects of vapor leaks from the fuel and 

evaporative control systems.388 

In the NPRM, EPA included a substantial discussion of the work we 

conducted on high evaporative emission rates and our rationale for the need for a 

leak standard to help address these concerns. No commenter challenged the data or 

the premises for our conclusion that a leak standard was needed. Manufacturers 

asked that the leak standard be phased-in with the Tier 3 evaporative emission 

standards and that use of upgraded OBDII evaporative system monitoring capability

be included as part of the in-use verification program (IUVP) provisions. Both 

elements are contained in this final rule. CARB fully supported the proposed leak 

standard and test procedure and indicated its intent to adopt such provisions after 

the Tier 3 FRM is adopted. 

2. Nature, Scope and Timing of Leak Standard

The evaporative emission standards in this FRM will help to promote 

widespread use of improved technology and materials which will reduce 

evaporative emissions in-use. The new requirement for a leak standard and test 

procedure will help to ensure the durability of Tier 3 evaporative emission control 

systems nationwide. As discussed in the technological feasibility discussion in 

Section IV.C above, the actions of manufacturers to meet the Tier 3 evaporative 

emission standards are expected to address fuel/evaporative system design features 

which currently have a greater propensity for developing leaks and thus improve 

in-use durability for evaporative control systems compared to vehicles meeting 

previous evaporative emission standards. The leak standard will provide added 

assurance that as the manufacturers design for “zero evap” standards they also 

design the systems to avoid leaks over the full useful life.

Based on the information described above concerning evaporative emissions 

in-use, we believe a leak standard is necessary to ensure that vehicles meeting Tier 

3 evaporative emission requirements not have evaporative emissions in excess of 

the Tier 3 standards for their full useful life. Toward that end, we are finalizing a 

leak standard to be met both at new vehicle certification and in use for IUVP 

 

388 Existing OBD regulations specify that if the fuel tank volume exceeds 25 gallons then the 

manufacturer may seek a larger leak detection orifice value. If a manufacturer seeks and is granted a 

larger value for OBD leak detection purposes, then that same numerical value becomes the leak 

standard value. We do not expect this value to exceed 0.040 inches.
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testing. The leak standard will apply beginning in the 2017 MY to vehicles in the 

20/20 option for that year and in the 2018 MY and later model years to any vehicle 

certified to the Tier 3 evaporative emission standards or a CARB carryover vehicle 

counted toward the sales percentage phase-in requirements discussed in Section 

IV.C, including LDVs, LDTs, MDPVs, and complete HDGVs up to 14,000 lbs 

GVWR. The standard will be applicable for the same useful life period as for the 

evaporative emission standards that apply to the vehicle. The standard will apply to 

vehicles using volatile fuel (e.g., gasoline, FFV, and methanol fuel vehicles, but not 

diesel or CNG vehicles).

To be compatible with CARB OBD requirements being met by most 

manufacturers and the OBD requirements included in this notice, we are specifying

that the leak standard be expressed in the form of a cumulative equivalent orifice 

diameter. We are finalizing a value of 0.02 inches.389 The standard basically 

requires that the cumulative equivalent diameter of any orifices or “leaks” in the 

system not exceed 0.02 inches. This is consistent with California OBD requirements 

(and those being finalized in this rule as well) that the OBD system be capable of 

identifying leaks in the fuel/evaporative system of a cumulative equivalent diameter 

of 0.020 inches EPA believes a standard at this level is feasible since earlier 

testing programs identified vehicles with essentially no leaks and it is essentially

equivalent to that required for CARB OBD evaporative system leak monitoring. We 

are finalizing a leak standard of 0.02 inches which with rounding is a bit less 

stringent than the 0.020 inch OBD evaporative system leak monitoring requirement. 

EPA believes this level of precision is sufficient to accomplish the air quality

objective and yet provides some compliance margin between the standard and the 

monitor requirement such as is reflected through multipliers for the exhaust 

emission standards established for other OBD monitors. The leak standard will be 

specified to one significant digit (e.g., 0.02 inches) but will have to be measured 

and reported to at least two significant digits.

The leak standard will apply at the time of certification as well as during 

confirmatory and in-use verification program testing. We do not expect that new 

vehicles being certified will have a leak problem, and since a vehicle with a leak 

would likely fail the evaporative emissions SHED test, there is little value in 

mandating a leak test at certification. Thus, EPA will permit a manufacturer to 

attest to compliance with the leak standard at certification.

To implement the leak standard within the existing regulatory structure a 

few minor rule changes are being made. First, existing EPA regulations such as 

 

389 Existing OBD regulations specify that if the fuel tank volume exceeds 25 gallons then the 

manufacturer may seek a larger leak detection orifice value. If a manufacturer seeks and is granted a 

larger value for OBD leak detection purposes, then that same numerical value becomes the leak 

standard value. We do not expect this value to exceed 0.040 inches.
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those at §86.098-24, specify criteria for evaporative/refueling emission families. 

EPA believes this basic structure is appropriate for the leak standard, with the 

additional criteria that vehicles in the same evaporative/refueling family must use 

the same basic approach to OBD leak detection. Significantly different volume fuel 

tanks would likely also be a family determinant, but we believe this is already 

covered by the evaporative/ refueling family criteria. Second, since the leak 

standard is a pass/fail requirement and not an emission rate, there is no requirement 

for the application of a deterioration factor. Third, EPA requires that the 

manufacturers recommend two or more leak test points for each test group. One of 

these points should be near the canister/purge valve (ideally in the vapor line 

between the canister/purge valve and the fuel tank) and the other in the gas cap/fill 

pipe area. Three points are required for vehicles with two separate evaporative and 

refueling canisters such as non-integrated ORVR systems which employ two 

activated carbon canisters and four points are required for vehicles with dual fuel 

tanks and two separate evaporative/refueling control systems.

EPA believes that linking the timing of the leak standard to the beginning of 

the phase-in of the Tier 3 evaporative emission standards in the 2018 model year 

provides adequate lead time and is consistent with the technical rationale supporting 

the feasibility of the Tier 3 evaporative emission standard. 

3. Leak Standard Test Procedure 

The fundamental concepts underlying fuel/evaporative system leak test are 

not new to the manufacturers. There is already a simple leak check in 40 CFR 

86.608-98(a)(1)(xii)(A) and in the past at least three states included a 

fuel/evaporative system pressure leak test in I/M programs. More importantly, all 

LDVs, LDTs, MDPVs and HDGVs manufactured today have the onboard 

capability to run a pressure or vacuum leak based check on the vehicle’s 

evaporative emission system as part of OBD evaporative system leak monitoring. 

These systems employ either positive or negative pressure leak detection pumps or 

operate based on natural vacuum for negative pressure leak detection. EPA is 

finalizing a test based on a similar concept of placing the system under a slight 

positive pressure (but from an external source), measuring the flow needed to 

maintain that pressure in the fuel/evaporative control system, and converting that 

flow rate to an equivalent orifice diameter. With regard to the test procedure we 

will first discuss where the leak test can occur in the FTP test sequence. We will 

then discuss how the test is to be conducted. EPA proposed this test procedure as 

part of the NPRM and discussed it extensively in the preamble to the proposed rule, 

and provided a full draft of the Recommended Practice for comment as an 
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Appendix to the RIA. No comments were received. We are finalizing this test 

procedure as proposed.390

First, when conducted, the leak test should be completed immediately

following the first two preconditioning steps within the FTP sequence (see Figure 

B96-10 in 40 CFR 86.130-96). Thus, the vehicle preconditioning steps for the leak 

test are: (1) fill the vehicle fuel tank to 40 percent of capacity using the appropriate 

certification test fuel and then (2) let the vehicle soak for a minimum of a six hour 

period at a temperature in the range of 68-86 °F. EPA requires that the test be 

conducted with 9 RVP E10 test fuel for both certification and IUVP.391 After 

preconditioning is complete, the leak test is conducted and the test sequence 

proceeds as prescribed in subpart B or testing is terminated if the purpose is only to 

conduct leak testing. EPA believes this modest level of preconditioning is 

sufficient to create standard conditions which enable repeatable and reliable 

measurement results. Preconditioning cannot include any prescreening for leaks nor 

will any tightening of fittings or connections be permitted. 

After preconditioning is complete, manufacturers then run the leak test. To 

fully complete testing on a vehicle, two or more test points are required depending 

on the fuel evaporative system configuration. All points must pass for the vehicle 

test to be a pass. As discussed above, one of these points should be near the 

canister/purge valve (ideally in the vapor line between the canister/purge valve and 

the fuel tank) and the other in the gas cap/fill pipe area. Three points are required 

for vehicles with two separate evaporative and refueling canisters such as nonintegrated ORVR systems which employ two activated carbon canisters and four 

points are required for vehicles with dual fuel tanks and two separate 

evaporative/refueling control systems such as dual tank LDTs. If the fuel/

evaporative system has an embedded evaporative system test port then that point 

can be used. Also, a manufacturer can develop a test rig such as a “fill pipe 

extension” which screws into the fill pipe opening using cap threads at one end and 

on the other end has threads to screw the fill pipe vehicle cap in place. Within this 

extension there must be an access port for the leak test equipment to be attached. 

Thus, the full system could be tested without any direct intrusion or the need for a 

separate gas cap assessment. The manufacturer must specify the test points at the 

time of the pre-certification meeting. If the manufacturer selects an entry point 

which requires the fuel cap to be removed, then the cap will have to undergo a 

 

390 Smith, P. and Passavant, G., “Recommended Test Procedure and Supporting Testing Data for the 

Evaporative Emissions Leak Test”, December 2013.

391 This is the same preconditioning that is called for in existing 40 CFR 86 subpart B for exhaust, 

evaporative, and refueling emissions testing. EPA will consider permitting the leak standard to be 

evaluated using CARB LEV III test fuel if CARB ultimately adopts this requirement.
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separate test as is now done in many I/M stations.392 In this case, tests from both 

points combined must pass the standard. Manufacturers commented that only one 

test point was needed, but when asked by EPA they offered no data to counter that 

provided by EPA in the NPRM which showed the potential for different results at 

different test point locations for the same vehicle.

The procedure is conducted as follows:

 Calibrate the testing apparatus and otherwise verify testing apparatus is 

ready and able to complete the procedure 

 Seal fuel system so as to pressure test entire system (purge valve, cap, 

etc.) 

 Attach test apparatus to vehicle’s fuel system at selected test point 

 Pressurize fuel system with nitrogen or another inert gas to at least 2.4 

kilopascals (kPa) 

 Allow flow and pressure to stabilize in accordance with specification 

provided in the regulatory text 

 Calculate effective leak orifice diameter from measured output flow rate 

and temperature and pressure data or use apparatus with built in 

computer providing an equivalent digital readout. Calculate to the 

nearest 0.01 inch. 

 Calculated effective orifice diameter must be less than or equal to the 

standard 

 If leak test is conducted at the fuel cap opening then the manufacturer 

must also show evidence that the vehicle’s fuel cap is performing 

properly.

393

 Use two or more separate test points, near the evaporative canister/purge 

valve and the other near the fuel cap are required. This is especially

 

392 For related information see “IM240 & Evap Technical Guidance”, EPA 420-R-00-007, April, 

2000. 

393 Such tests are done routinely in I/M stations using a commercially available apparatus. The gas 

cap leak rate may be determined by pressure loss measurement, direct flow measurement, or flow

comparison methods and shall be compared to a pass/fail flow rate standard of 60 cubic centimeters 

per minute of air at 30 inches of water column. The flow rate methods are referenced to standard 

conditions of 70 °F and 1 atm. 
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important if the fuel cap/fill neck area is isolated from the rest of the 

fuel/evaporative system as a result of the 40 percent fill or if dual tanks 

are not otherwise connected through vapor lines. 

 Tests can be void if the test apparatus fails, becomes disconnected, fails 

to maintain a stable flow rate or pressure, or the test was stopped before 

completion due to safety considerations or some other relevant vehicle 

issue. 

 Leak tests at all points (2 or more depending on the fuel 

tank/evaporative system configuration) must pass for a vehicle to pass. 

This includes performance within specification for the fuel cap if it is 

removed for testing.

The test procedure presented above is based on current fuel system designs. 

In the future, it is reasonable to expect changes in designs of the fuel systems such 

that the procedure above may need adjustment. EPA will monitor these fuel system 

changes and modify the test procedure provisions as needed. Furthermore, existing

EPA regulations (see §1065.10(c)) contain provisions which provide the 

opportunity for manufacturers to seek approval for special or alternate test 

procedures if from a practical perspective their systems cannot be evaluated under 

EPA requirements or they have an approach deemed equivalent or better. Any such 

special or alternative procedures must be reported under §86.004-21(b)(9).

4. Certification and Compliance

As part of the Compliance Assistance Program (CAP 2000) in-use 

verification program (IUVP)394 the manufacturers began testing the evaporative 

emissions performance of small samples of in-use vehicles owned and used by the 

public. These regulations can be found at 40 CFR 86 1845-01, and 1845-04. In 

2000, EPA extended this requirement to cover chassis-certified HDVs, which for 

these purposes are basically all HDGVs up to 14,000 lbs GVWR.395 The in-use 

testing for evaporative emissions started in 2004 for 2001 MY LDVs, LDTs, and 

MDPVs and in 2008 for 2007 MY chassis certified HDGVs. Current IUVP data for 

evaporative emissions (including LDVs, LDTs, MDPVs, and HDGVs up to 14,000 

lbs GVWR) covers about 1800 vehicle tests. These data show that when evaluated 

in the laboratory using certification test procedures, the vast majority (over 95 

percent) of the vehicles pass the evaporative emission standards to which they were 

certified. While this information is indicative of good in-use performance, it has 

limitations. First, the test results are for small sample sizes. For the approximately 

 

394 See 64 FR 23906 (May 4, 1999).

395 See 65 FR 59922-59924 (October 6, 2000).
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150 million LDVs, LDTs, MDPVs, and chassis-certified HDGVs produced between 

2001 (the start of the IUVP program) and 2010 (latest available data), only about 

0.001 percent of vehicles were tested. Second, the IUVP regulations place limits on 

the age/mileage for vehicle testing. Each model year is tested in two “batches,” 

nominally at the one and four year age points. One year old vehicles must have at 

least 10,000 miles and four year old vehicles must have at least 50,000 miles with at 

least one within the higher mileage group having an odometer reading of at least 75 

percent of useful life (90,000 miles for most Tier 2 vehicles). With the even longer 

useful life periods under Tier 3, attention to in-use durability for evaporative 

systems becomes even more important. Including the leak standard within the 

IUVP protocol, as structured in the discussion below, will provide better 

information to EPA and manufacturers concerning evaporative system performance 

and help to focus manufacturer efforts on using designs and hardware with full 

useful life durability in mind.

a. In-Use Verification Program (IUVP) Requirements for the Leak 

Standard 

i. Introduction

We believe it is important to identify leaks since vehicles with leaks are

expected to have daily emission rates above the Tier 3 evaporative emissions 

standards, and the recent laboratory and field data382 suggest a propensity for the 

diameter of vehicle leak orifice to get larger over time and thus to have even higher 

emissions. This is also important because evaporative leak emissions occur virtually

every day whether the vehicle is driven or not. Thus identifying potential leak 

problems is important to capturing the emission benefits of the Tier 3 evaporative 

emission requirements.

Toward that end, EPA is including assessment of compliance with the leak 

standard within the IUVP program. In developing the proposed rule, we considered 

expanding the evaporative emission testing portion of the IUVP program as a 

means to assess leaks, but we decided to focus on the leak standard because it is less 

burdensome than a full evaporative emissions SHED test and is a cost effective step 

toward assessing many aspects of evaporative emissions performance in-use.

EPA believes adding a leak test requirement does not create an unreasonable 

burden. The test procedure described above is simple to run, inexpensive to conduct 

in terms of equipment and labor, and can be completed relatively quickly compared 

to an evaporative emissions test. However, we are retaining the evaporative 

emissions testing requirements currently in IUVP to monitor broader evaporative 

control system effectiveness (e.g., purge, canister control efficiency, permeation). 
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ii. IUVP Test Requirements 

We are requiring that the leak test be conducted for each and every vehicle 

assessed in IUVP for exhaust emissions under 40 CFR 86.1845-04. This will begin 

for 2017 MY vehicles meeting the leak standard under the 20/20 option and more 

fully in the 2018 MY certifications for all test groups meeting the new leak 

standard. The leak test IUVP requirement includes the low and high mileage tests 

for any exhaust vehicle evaluated for exhaust emissions plus a requirement that 

there be at least one representative of each evaporative/refueling/leak family 

evaluated at each mileage/year point. We are finalizing this approach to 

implementing IUVP for the leak standard in lieu of creating a new set of 

requirements which would require another set of vehicles to be procured for testing. 

We are not including the leak test with any evaporative emissions test in IUVP, 

since a leak will be evident in the results of the evaporative emissions test.

The existing IUVP regulations at §86.1845-04, Table S04-07, call for test 

sample sizes on a sliding scale based on annual vehicle sales by test group. This can 

vary from zero for very small sales test groups to six vehicles for test groups with 

sales exceeding 250,000. There are more exhaust emission test groups than there 

are evaporative/refueling test families and exhaust emission test groups may cover 

one or more of the same evaporative/refueling/leak families, so we expect to receive 

multiple leak test results for most evaporative/ refueling/leak families. This will 

expand the amount of IUVP data we receive in this important area and improve our 

ability to assess the overall leak performance for a given evaporative/refueling/leak 

family and the fleet as a whole.

As discussed above, EPA believes that the fuel and evaporative control 

system leaks are heavily influenced by age as well as design and other factors. EPA 

asked comment on extending the age point for leak testing for IUVP beyond the 

four year point to better assess this effect. However, in the past, manufacturers have 

expressed concern about the implications of testing older vehicles and about finding 

vehicles still within their warranty and recall liability periods. EPA believes further 

consideration of longer year test points is merited for exhaust, evaporative, 

refueling and leak tests but because such a change could potentially affect all four 

tests we have decided to defer that action to a broader IUVP program review. 

Extending the time point for the leak test alone would create a different 

programmatic test burden in terms of more vehicle procurements than the program 

laid out above.

iii.Assessment of IUVP Leak Emission Standard Test Results

The existing regulations contain provisions addressing follow-on testing 

requirements for exhaust emissions for vehicles which fail to meet various 

performance thresholds within IUVP (see 40 CFR 86.1846-01). As mentioned 

above, we expect that it will be common to get more than one leak test result over 
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the course of each model year’s mileage testing point for each evaporative/

refueling/leak family as a result of the requirement to assess leaks with each exhaust 

IUVP test. However, the leak standard is basically pass/fail at 0.02 inches and it is 

difficult to establish a threshold criteria for a pass/fail standard such as has been 

done for exhaust emissions where there is a multiplier applied to the level of the 

individual exhaust emission standard.

Given the importance of the leak standard in assuring in-use evaporative 

emissions control, we are finalizing a set of criteria for assessing leak standard 

results from IUVP. These criteria can be summarized as follows for each low and 

high mileage test point for each model year tested:

 lf 50 percent or more of all vehicles evaluated in an evaporative/refueling/leak 

emission family for any given model year pass the leak standard, testing is 

complete. This applies to cumulative testing for that family throughout the 

model year for that mileage group. This is consistent with the exhaust emission 

requirements for IUVP and EPA believes it is reasonable since vehicles are 

tested in the “as received” condition from consumers.

 If only one representative of the evaporative/refueling/leak family is tested in a 

mileage group for that model year’s vehicles and it passes the leak standard 

testing is complete. If that vehicle does not pass the leak standard a 

manufacturer may test an additional vehicle to achieve the 50 percent rate.

 If an evaporative/refueling/leak emission family fails to achieve the 50 percent 

rate, it is presumed that the family will enter into In-Use Confirmatory Testing 

Program (IUCP).

Before IUCP begins, the manufacturer may ask for engineering analysis 

discussions with EPA to evaluate and understand the technical reasons for the 

testing outcomes and the implications for the broader fleet. Technical information 

for these discussions could include but will not be limited to detailed system design, 

calibration, and operating information, technical explanations as to why the 

individual vehicles tested failed the leak standard, and comparisons to other similar 

families from the same manufacturer. Relevant information from the manufacturer 

such as data or other information on owner complaints, technical service bulletins, 

service campaigns, special policy warranty programs, warranty repair data, state 

I/M data, and data available from other manufacturer specific programs or 

initiatives could help inform understanding of implications for the broader fleet. As 

part of this process a manufacturer could elect to provide evaporative emissions 

SHED test data on the individual vehicle(s) that did not pass the leak standard 

during IUVP. With an adequate technical basis, the outcome of this engineering 

analysis discussion could result in an EPA decision not to require IUCP testing. 
Page 266 of 529

We will operate within the basic structure of the IUCP program in the 

existing regulations. Prior to commencing IUCP testing the manufacturer, after 

consultation with EPA submits a written plan describing the details of the vehicle 

procurement, maintenance, and testing procedures. This plan could include 

inclusion of a hot soak plus diurnal SHED test to supplement leak test results. EPA 

must approve this plan before testing begins. As prescribed in the IUCP regulations 

for exhaust, if five vehicles are tested and all pass the leak standard then testing will

be complete. If all five vehicles do not pass, then five more are tested. More 

vehicles can be tested at the manufacturer’s discretion but all testing must be 

completed within the time period specified in the regulations. EPA and the 

manufacturer then enter into discussions regarding interpretation, technical 

understanding, and compliance/enforcement implications of the test results, if any. 

iv. Optional Test Procedure Approach for IUVP/IUCP

With the implementation of the OBD regulation changes in Section IV.E 

below regarding evaporative system leak rate monitoring, EPA is finalizing an 

optional approach to a portion of the leak test procedure. This optional testing 

approach is included in the IUVP/IUCP testing program for the leak standard, but 

will not be used for certification testing for the leak standard. EPA can also use this 

procedure for conducting compliance assessments. Under this optional approach 

manufacturers will be able to rely upon the operation of their OBD evaporative 

system leak detection hardware and operating protocols in lieu of running the stand 

alone in-use leak test to check for the presence of a 0.02 inch leak in the 

fuel/evaporative system.

Quite simply, if a vehicle is brought in for IUVP or IUCP testing and a scan 

tool query of the onboard computer indicates that the vehicle has successfully

completed a full OBD-based evaporative system leak monitoring check within the

last 750 miles and no evaporative system leak problems for any diameter above 

0.020 inches are indicated (no pending or confirmed diagnostic trouble code(s)

P0440, P0442, P0446, P0455, P0456, or P0457), the vehicle would be deemed to 

have met and passed the leak standard test requirement. However, if the system has

not successfully completed a full OBD-based evaporative system leak check within 

750 miles with no problem indicated then the manufacturer will have the option to 

run its OBD-based evaporative system leak check in the laboratory after prescribed 

preconditioning. This OBD-based approach is sometimes used in auto 

manufacturer dealerships and repair facilities to diagnose and fix evaporative 

system leaks found by the OBD system. If the vehicle completes the full OBDbased leak test in the laboratory then the vehicle’s pass/fail results for the 0.02 inch 

cumulative equivalent diameter orifice will be based on the OBD test result. This 

optional protocol can apply to every leak standard test after certification unless not 

approved by EPA for IUCP under 40 CFR 1846.01(i). Replicate tests will not be 

required or allowed but void tests could be repeated. 
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Furthermore, EPA will permit the manufacturer to run the stand alone EPA 

leak test in several situations. First, manufacturers can conduct the stand alone test 

to confirm that a problem identified by the OBD-based evaporative system 

monitoring leak check is a leak and not a problem with the OBD leak monitor itself. 

Second, a manufacturer can run the stand alone EPA leak test to confirm that the 

leak value identified by the OBD system is truly above the level of the leak 

standard. Third, it can be used for vehicles which have not successfully completed 

a full OBD-based evaporative system leak monitoring check within the last 750 

miles. Fourth, it can be used to confirm that a DTC set within the last 750 miles 

actually indicates the presence of a leak(s) greater than the standard. However, if a 

manufacturer elects to use only OBD-based evaporative system leak based 

monitoring in its IUVP testing; these results will be the basis for decisions 

regarding IUCP. As required in the existing IUVP regulations, all test data whether 

OBD based or based on EPA’s stand alone test procedure must be reported to EPA.

There may be some advantages to this option since it employs a 

pressure/vacuum approach manufacturers understand and creates positive/negative 

pressures manufacturers have accommodated within their fuel/evaporative system. 

One potential downside is that under current designs vehicle engines will have to be 

operating to create the pressure or vacuum and because the engine is operating this 

will require the OBD-based leak test to be stand alone after the preconditioning 

sequence is complete. This will be more challenging for natural vacuum leak 

detection systems unless extended driving is involved to create the fuel system heat 

needed for a natural vacuum event or this is done through a climate chamber or 

SHED based diurnal heat build.

Allowing for this approach raises at least two implementation questions. 

The first is related to the value of conducting the OBD-based test for a vehicle with 

a confirmed or pending leak DTC already set in the computer and/or an MIL 

indicated. In this case, EPA will permit the manufacturer to run the OBD-based 

leak test and/or the stand alone EPA leak test or concede that the vehicle will not 

pass the leak standard and count the result. Second is the question of gas caps. This 

is among the most common codes found in OBD records and is often related to 

operator error such as not tightening the gas cap properly. Codes of this nature have 

no value in this leak assessment, so a manufacturer will be permitted to correct the 

problem before testing and clear this OBD code before testing or run the stand 

alone EPA leak test. 
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E. Onboard Diagnostic System Requirements

1. Onboard Diagnostic (OBD) System Regulation Changes - Timing

EPA first adopted OBD requirements for 1994 and later model year LDVs 

and LDTs. While EPA has extended its requirements from LDVs and LDTs to 

larger and heavier vehicles,396 EPA’s last broad upgrade to its basic OBD regulation 

was in the 2005 timeframe. Since that time, CARB has adopted and the 

manufacturers have implemented a number of additional provisions to enhance the 

effectiveness of their OBD programs. These provisions include new requirements 

for OBD evaporative system leak detection as well as provisions to help insure that 

systems are built and operate as designed over their full useful life, give reliable 

results (find and signal only true deficiencies), and operate frequently during in use 

operation. It is permitted in existing EPA regulations and is common practice for 

the industry to certify their OBD systems with CARB and for EPA to accept CARB 

OBD certifications as satisfying EPA requirements. EPA is continuing that practice 

and we are updating our regulations to be consistent with the latest CARB 

regulations.

EPA proposed to adopt, with a few adjustments, the CARB regulatory

requirements related to OBD II (see California Code of Regulations (CCR) §1968.2 

dated May 18, 2010). We received comment from CARB that since our NPRM 

was issued, they were s completing an update of their OBD II regulations and that 

EPA should adopt these provisions in lieu of the May 18, 2010 provisions.397 We 

have reviewed these updates and concur with the commenters, so we are adopting 

the provisions officially approved by CARBs Office of Administrative Law on July

31, 2013. We are also adding provisions and continuing the exceptions as discussed 

below. The changes we are adopting do not include any changes to requirements 

for engines used in vehicles over 14,000 lbs GVWR or to vehicles over 14,000 lbs 

GVWR, except for HDGVs optionally certified using chassis procedures. To be 

consistent with the manner in which the Tier 3 exhaust emission standards are being 

implemented for the heavy-duty vehicles between 8,501 and 14,000 lbs GVWR, the 

OBD requirements will be based on the Job 1 (first production) date for the 

vehicle/engine model. If the vehicle/engine model Job 1 date is before the fourth 

anniversary date of the signature of the Tier 3 rule the requirements will not be 

mandatory in that model year. If the Job 1 date is on or after the fourth anniversary

of the signature date of the Tier 3 rule the OBD requirements will apply in that 

model year. The Tier 3 OBD requirements will apply to all 8,501-14,000 lb HDVs 

 

396 EPA’s OBD regulations for LDVs, LDTs, and MDPVs, are found at 40 CFR 86.1806-05. EPA 

has also adopted OBD requirements for incompletes and heavier vehicles (greater than 14,000 lbs 

GVWR) (see 74 FR 8324, February 24, 2009 and 40 CFR 86.010-18). 

397 The latest update of CARB’s OBD regulations was adopted on July 31, 2013. See section 

1968.2 at http://www.arb.ca.gov/msprog/obdprog/obdregs.htm/
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in the 2020 model year. To be consistent with the manner in which the Tier 3 

exhaust emission standards 

We are taking this approach to OBD for three basic reasons. First, this is 

consistent with the goal of a national program and one vehicle technology for all 50 

states. Second, compliance with the current CARB OBDII requirements is now 

demonstrated technology, compliance with these requirements is common within 

the industry today, and we expect that to continue in the future with the 2013 

CARB changes. Thus, the added burden is minimal since essentially all 

manufacturers certify their CARB OBD systems nationwide with EPA. Third, the 

latest OBD systems run frequently on in-use vehicles to identify potential exhaust 

and evaporative system performance problems, so adopting these provisions will

create the opportunity for OBD to serve a more prominent role in ensuring the Tier 

3 emission standards are met in-use. 

Alignment with the existing CARB OBD II requirements will be required by

the 2017 MY, except as discussed below. Manufacturers requested a phase-in 

compliance approach in lieu of a fixed compliance date, but no specific justification 

was provided by the commenters and EPA could not establish a need for this 

accommodation since the most recent changes to CARB OBDII regulations (2013) 

did not meaningfully affect provisions regarding vehicles/engines under 14,000 lbs 

GVWR which have been in place since 2006. LDVs, LDTs, MDPVs and vehicles 

under 14,000 lbs GVWR already comply with CARB OBDII requirements and use 

the CARB certification as the basis for EPA certification. . 

There is an important link between OBD provisions related to evaporative 

emission control system leak monitoring and the leak standard. They each provide 

an important incentive to design fuel/evaporative systems with fewer propensities to 

develop leaks in use but each addresses the issue from a different perspective. The 

distinction is that the leak standard prohibits leaks of greater than 0.02 inches 

cumulative equivalent diameter, while the OBD evaporative system leak monitoring 

provision requires that the OBD system find leaks larger than 0.020 inches 

cumulative equivalent orifice diameter and notify the owner, but with no explicit 

requirement to repair the problem. Thus adopting a 0.020 inch cumulative 

equivalent orifice diameter aligns these two programs and, as discussed above, 

facilitates the use of OBD evaporative system leak monitoring hardware/strategy as 

an optional leak detection test procedure for in-use testing.

With regard to OBD evaporative system leak detection, EPA received 

comment that we should permit a phase-in for compliance with the 0.020” 

evaporative system leak monitoring requirement. Even though the 0.020” leak 

monitoring requirement has been in place since the 2004MY for CARB OBDII, and 

essentially manufacturers have met it for years, the existing EPA regulation actually 

only requires monitoring at the 0.040” threshold level. After considering the 

comments received, EPA is permitting a limited and minimal phase-in for the 
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0.020” leak detection criterion for the OBD evaporative system monitoring 

requirement. We are permitting this phase-in, because a few vehicle models still 

only meet the 0.040” monitoring threshold in their Federal configuration and 

complying with the 0.020” CARB OBD II requirement entails validating 

performance in high altitude and cold weather regimes not seen in California. Thus, 

the 0.020” requirement would be new for those few models currently certified only

to the EPA evaporative leak monitoring requirement. We are, therefore, 

implementing the following phase-in provision for the 0.020” leak detection 

criterion for the OBD evaporative system monitoring requirement. First, if a 

vehicle model meets the 0.020”requirement in the 2016 model year it is not eligible 

for the phase-in provision. No backsliding is permitted. Second, for manufacturers 

with models not meeting the CARB OBDII evaporative system leak monitoring 

requirement in the 2016 MY(see 13 CCR 1968.2(e)(4)), they will be permitted to 

delay product-wide compliance with the 0.020” leak provision of the evaporative 

system monitoring requirements until the 2018 model year by engaging in a 

voluntary early phase-in. This phase-in would begin in the 2016 model year and 

conclude in the 2018 model year at a 100 percent implementation rate. For example, 

a manufacturer could delay attaining 100 percent compliance with the OBD 

evaporative system leak monitoring requirement until the 2018 model year by

complying in the 2016 model year using a percentage which is at least as large as 

the delay for the 2017 model year (e.g., 40% in 2016 MY, 60% in 2017MY, and 

100% in 2018MY).

2. Revisions to EPA OBD Regulatory Requirements

As discussed above, we are updating our OBD regulations to be consistent 

with current California OBD II requirements. We are incorporating by reference 

section 1968.2 of the California Code of Regulations as adopted July 31, 2013 (13 

CCR 1968.2). This includes paragraphs (c) through (j) in their entirety. These 

paragraphs are entitled: (c) Definitions, (d) General Requirements, (e) Monitoring 

Requirements for Gasoline/Spark Ignited Engines, (f) Monitoring Requirements for 

Diesel/Compression Ignition Engines, (g) Standardization Requirements, (h) 

Monitoring System Demonstration Requirements for Certification, (i) Certification 

Documentation, (j) Production Vehicle Evaluation Testing. The substance of 

many of these provisions is already contained in existing EPA OBD requirements 

for LDVs, LDTs, MDPVs, and complete HDGVs less than 14,000 lbs GVWR.398 399 

EPA will continue to accept certifications with CARB OBD requirements as 

satisfying EPA OBD requirements.

 

398 MDVs in the CARB regulations basically incorporate MDPVs and complete HDGV less than 

14,000 lbs GVWR as defined by EPA.

399 We are not changing the requirement for incompletes and vehicles with a GVWR above 14,000 

lbs. 
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The most noteworthy changes we are finalizing are summarized below. The 

CCR below is the California Code of Regulations cite for each pertinent provision.

 EPA is adding a 0.020 inches leak detection monitoring threshold upstream 

of the purge valve for all 4 vehicle categories LDV, LDT, MDPV, and 

complete HDGVs up to 14,000 lbs GVWR except for those with fuel tanks 

larger than 25 gallons capacity (see 13 CCR 1968.2(e)). OBD leak 

monitoring systems will have to identify, store, and if required signal any

leak(s) equal to or greater than 0.020 inches cumulative equivalent diameter. 

This will thus include diagnostic trouble codes (DTC) P0440, P0442, P0446, 

P0455, P0456, and P0457.

 EPA is incorporating by reference the full array of rate based monitoring 

requirements (see 13 CCR1968.2 (d)(3)-(6)). Meeting the rate based 

monitoring requirements will help to insure that, even with enable criteria, 

the exhaust and evaporative system monitors run frequently enough that on 

average a problem would be identified and signaled to the owner in 

operation within two weeks. This will help to improve the fraction of time 

monitors are ready to find a potential problem.

 EPA is incorporating by reference provisions regarding monitoring system 

demonstration requirements for certification. We are incorporating by

reference CARB provisions in this area and accepting submissions to CARB 

for purposes of compliance demonstration (see 13 CCR 1968.2(h)). 

Adopting current CARB monitoring system demonstration requirements 

assures that monitoring systems operate as designed when installed on 

certification vehicles.

 EPA is incorporating by reference the CARB production vehicle evaluation 

data program. This program requires manufacturers to demonstrate that the 

OBD system functions as designed and certified when installed on 

production vehicles. (See 13 CCR 1968.2(j)).

In addition, we are adding two new requirements, and retaining three 

minor exceptions. Each of these actions is described separately below.

 We are adding the requirement that before certification a manufacturer must

demonstrate the ability of its OBD leak monitoring system to detect and 

report a 0.020 inch leak in the fuel/evaporative system. Current CARB 

protocols within 13 CCR 1968.2(h)(3) do not require this demonstration as 

part of certification. This requirement helps to ensure the OBD system’s 

capability to function as designed and the OBD-based evaporative system 

leak monitoring hardware to be used as an optional test procedure for IUVP 

testing for the leak standard. This requirement being added for the same 

vehicles that are subject to monitoring system demonstration requirements 
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for certification under CARB OBD regulations under 1968.2(h)(3).

400

 EPA 

test procedures are contained in 40CFR 86.1806-17(b). In the spirit of 

aligning CARB and EPA OBD provisions, if CARB ultimately adopts this 

demonstration requirement and CARB’s test procedure provisions fulfill the 

purpose of the EPA requirement, EPA will strongly consider proposing to 

adopt the CARB test procedures in lieu of those in 40 CFR 86.1806-17(b). 

This requirement applies to any vehicle test group certified to the OBD 

0.020” evaporative system leak monitoring requirement. Since the

regulation requires only a relative few test groups each model year per 

manufacturer, we will permit the manufacturers either to meet the 

requirement for the remainder of its test groups on production vehicles of a 

previous model year which used the identical monitoring hardware and 

strategies or to certify by attestation that each of their remaining test groups

meets the requirement based on development, calibration, and other 

information. If a manufacturer chooses to certify by attestation for some test 

groups for a given model year, the regulations are structured such that over 

several model years a manufacturer would evaluate through testing all test 

groups as new groups are selected in subsequent model years. 

 For the OBD evaporative system leak monitoring requirement, EPA is 

establishing a requirement for a scan tool readable function (a new InfoType 

$14 in Service $09 of SAE J1979DA) which can be used to obtain the 

distance traveled since the OBD leak monitoring diagnostic was last 

completed successfully, i.e., the system passed or failed (identified any leak 

above 0.020 inches) during that monitoring event (unless it is otherwise 

already required in other OBD system modes). The purpose of this 

requirement is to facilitate implementation of the leak standard within 

IUVP, by permitting the use of OBD evaporative system monitoring results 

as a tool to make pass/fail determinations during IUVP. As discussed in 

section IV.D above, if a vehicle successfully completed an evaporative 

system leak monitoring within the most recent 750 miles then the 

manufacturer could use this result for its IUVP requirement for the leak 

standard. EPA asked for comment on how best to implement this 

requirement within the OBD system, in what model year(s) it should be 

required and to which vehicle classes it should apply.

Manufacturers supported this requirement, and suggested a lower cost 

approach which we are adopting in the final rule. Rather than requiring that 

the distance and monitoring results be stored in NVRAM to avoid false 

 

400 Passavant,G. (January, 2014). “Development of 0.020” Evaporative Leak Monitoring System 

Demonstration Requirement Test Procedure”. Memorandum to the docket.
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results based on a user induced code clear or battery disconnect, the 

manufacturers suggested that the “distance since evap monitoring decision” 

InfoType be reset to the maximum value ($FFFF/65,535km) when codes are 

cleared or after a reprogramming event (e.g., battery disconnect). The 

InfoType would be reset to zero km when an evaporative monitoring 

pass/fail decision is later made, allowing the mileage to be read directly at 

IUVP. In the usual situation where no user induced code clear or 

reprogramming event (e.g., battery disconnect) occurred, the mileage since 

the last decision could be read directly. In either circumstance, the presence 

of an evaporative system leak related DTC (P0440, P0442, P0446, P0455, 

P0456, and P0457 or manufacturer specific equivalent DTC) will indicate a 

failure and the lack of such a DTC will indicate a pass. The mileage and the 

pass/fail results will then be taken together for purposes of the 750 mile 

option in the IUVP assessment for the leak standard.401

This requirement applies to all vehicle categories subject to the leak test 

including LDVs, LDTs, MDPVs, and complete HDGVs less than 14,000 lbs 

GVWR. Manufacturers commented that this requirement should apply only 

to vehicles/test groups meeting the leak standard. Since the leak standard 

phases-in between 2018 and 2022 model years (2017 for manufacturers 

using the 20/20 evaporative emission option), a manufacturer may phase-in 

compliance with this requirement as well.

 The minor exceptions which are contained in EPA’s existing OBD 

regulations are to be continued. Compliance with 13 CCR 1968.2(d)(1.4), 

pertaining to tampering protection is not required. Also, the deficiency

provisions of 13 CCR 1968.2(k) are not being adopted. In addition, 

demonstration of compliance with 13 CCR 1968.2(e)(15.2.1)(C), to the 

extent it applies to the verification of proper alignment between the 

camshaft and crankshaft, will apply only to vehicles equipped with variable 

valve timing. For all model years, the deficiency provisions of paragraph (i) 

of the existing EPA regulations apply only to alternative fuel vehicle/engine 

manufacturers selecting this paragraph for demonstrating compliance.

These changes, taken together will improve the performance, reliability,

general utility, and effectiveness of OBD systems for Tier 3 exhaust and 

evaporative emission controls. Furthermore, these changes create the opportunity

for OBD evaporative system leak monitoring systems to serve a more prominent 

role in ensuring compliance with the leak standard. EPA believes that they can be 

implemented for minimal cost since most manufacturers are meeting them today

 

401 Passavant, G. (January, 2014). “Manufacturer Input on Distance Since Last Evaporative 

Monitoring Decision”. Memorandum to the docket.
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and will have to for LEV III vehicles. The provisions we are incorporating by

reference give manufacturers the flexibility to seek a revision to the emission 

threshold for a malfunction on any diagnostic required if the most reliable 

monitoring method developed requires a higher threshold to prevent significant 

errors of commission in detecting a malfunction.402 Any decision on a potential 

exception would be preceded by a consultation between EPA and CARB. 

As discussed below, the OBD requirements will apply to small entities in 

the 2022 model year, if they choose to take advantage of one of the revised 

implementation schedules for small volume manufacturers and small businesses. 

However, as is the case for larger manufacturers, no backsliding is permitted 

meaning that if they voluntarily meet the OBD requirements on their Federal 

configurations in the 2016 model year as a result of compliance with CARB 

regulations they must continue to meet the requirements on the Federal 

configurations in the 2017 and later model years. Small alternative fuel converters 

will still be able to meet the OBD requirements using the provisions of 40 CFR 85 

Subpart F. Finally, it should be noted that as CARB updates its OBD regulations in 

the future EPA will consider these changes and propose to adopt them or 

incorporate them by reference, if appropriate.

3. Provisions for Emergency Vehicles

It is common for emergency vehicles such as law enforcement, medical 

response, and fire protection vehicles operated by government entities to be derived 

from similar publicly available vehicle configurations. However, these vehicles 

often have chassis configurations, auxiliary equipment packages, and performance 

requirements different from the standard publicly available configurations. These 

emergency response vehicles typically meet the various EPA emission standards 

based on the engineering calibrations and emission control hardware used in the 

publicly available configuration. OBD requirements also apply to these vehicles and 

occasionally their unique design and/or operating characteristics may prevent them 

from meeting one or more of the various OBD requirements. 

In comments on the NPRM, one manufacturer raised a concern that EPA’s 

proposed adoption of the current CARB OBDII requirements for the 2017 model 

year would create a compliance problem for two of their law enforcement vehicle 

configurations. These two vehicle configurations cannot meet one element of the 

current CARB OBDII requirements (CCR §1968.2 (e)(6.2.1)(C)) without 

compromising the performance expected by law enforcement personnel.403 To 

address this issue CARB provided these vehicles an exemption from this provision, 

 

402 See 13 CCR 1968.2 (e)(17).

403 See Ford Motor Company comments on the Tier 3 NPRM at EPA-HQ-OAR-2011-0135-4349.
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by permitting it to meet Federal requirements as permitted by the California Vehicle 

Code. This solved the problem because the CARB OBD II provision of interest did 

not exist within the Federal OBD requirements at that time.

This raises both a near term and a broader policy issue related to emergency

vehicles. First, we are incorporating a definition for emergency vehicle that is 

specific to the Tier OBD requirements.404 Second,, with regard to the two law 

enforcement vehicle configurations identified by the manufacturer, EPA has 

reviewed the manufacturer’s technical information and agrees with CARB’s 

previous assessment.405 Thus, EPA will grant the manufacturer a three model year 

exemption from the requirement as requested by the manufacturer (MY2017-2019 

inclusive). Specifically, we are delaying the need to comply with the requirements 

of CCR §1968.2 (e)(6.2.1)(C)- incorporated by reference by EPA- until the 

2020MY for any emergency vehicle which does not meet the requirement in the 

2016 model year. This specifically applies to the two test groups identified by the 

commenter. Second, in a broader context, there is a need to address the potential 

future need for a deficiency or an exemption for emergency response vehicles. If 

CARB grants a deficiency for emergency response vehicles under CCR §1968.2(k) 

we would expect this to be done in consultation with EPA. Furthermore, we are 

incorporating provisions to address a potential situation where an emergency 

vehicle needs a deficiency (a temporary or permanent allowance for manufacturers 

to be non-compliant with a specific requirement of the OBD regulations as long as 

certain requirements are met) or exemption which is not addressed by CARB under 

CCR §1968.2(k). EPA is adopting a provision which authorizes us to address these 

circumstances based on an application from the manufacturer. Under this 

provision, EPA may approve a request for a deficiency or in extreme circumstances 

a temporary or potentially permanent exemption from a given OBD requirement. In 

considering decisions to approve/disapprove this request, EPA will consider the 

provisions of CCR §1968.2 (k)(1) plus engineering information and vehicle 

emission and performance data provided by the manufacturer which demonstrates 

significant vehicle engineering or system performance issues (e.g., vehicle speed, , 

acceleration, handling, safety, fuel economy, cost) related to complying with the 

OBD requirements. 

 

404 For the Tier 3 OBD requirements, emergency vehicle means a motor vehicle manufactured 

primarily for use as an ambulance or combination ambulance-hearse or for use by the United States 

Government or a State or local government for fire protection or law enforcement. 

405 Passavant, G, (January, 2014). Information Related to CARB AFRIM OBD Requirements for 

Emergency Vehicles. Memorandum to the docket.
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4. Future Considerations

EPA and CARB coordinate closely on OBD II requirements. When changes 

to the requirements occur, CARB provisions often precede those from EPA. Since 

LEV III begins before Tier 3, EPA expects that CARB will revise any OBD II 

requirements related to the LEV III before EPA would do so for Tier 3. EPA 

expects to work with CARB on any potential changes to OBD II requirements 

related to LEV III and to consider proposing such changes in a future action since 

we expect great commonality between Tier 3 and LEV III exhaust and evaporative 

emission control systems. Two presentations related to CARB’s initial thinking for 

LEV III related OBDII revisions are available in the docket.406 In the interim, for 

any Tier 3 exhaust emission bin which does not have a corresponding bin value in 

the Tier 2 program, the threshold for the exhaust emission malfunction criteria is 

that of the next higher bin in the Tier 2 regulation as prescribed for the latest model 

year in CCR 1968.2(e)(1)-(3) . 

In the NPRM, EPA discussed the basics of evaporative emission control 

technology and laid out concerns regarding the loss of evaporative and refueling 

emission control which occurs if a canister is not purged. This can potentially occur 

if the purge hardware fails or if the flow of purge air through the canister is 

impeded by foreign matter collecting at the inlet port or on the carbon itself, 

canister poisoning due to fuel or water intrusion, or activated carbon breakdown 

from phenomena such as road vibration. Failure of purge hardware is already 

covered by OBD and a recent study indicates that this is a relatively rare 

evaporative system problem.407 Failure of the activated carbon to purge due to 

problems such as those mentioned above are not covered by OBD. EPA is 

undertaking a study to better characterize the causes and frequency of such potential 

problems, and may propose in a future rulemaking an OBD-based monitoring 

requirement related to activated carbon/canister capture should the study indicate a 

significant frequency of loss of canister efficiency in-use and loss in emissions 

control relative to other evaporative system failure modes. 

In the NPRM we also asked for comment on several other issues related to 

the role of OBD in future technology fuel/evaporative control systems. This 

included pursuing a monitoring threshold less than the 0.020” cumulative diameter 

that we are finalizing in this notice for non- pressurized and pressurized fuel 

systems. We asked about the feasibility and cost of requiring the OBD leak 

detection monitoring system to detect and signal the presence of a smaller diameter 

 

406 McCarthy,M. , “CARB Light-duty OBD Regulation Update”, SAE 2012 Onboard Diagnostics 

Symposium, Nov 2012 and Remenus, M., “CARB Light-duty OBD Regulation Update”, SAE 2013 

Onboard Diagnostics Symposium, September 2013.

407 Weatherby, M., Sabisch, M., Kishan, S. (2014) Analysis of Evaporative On-Board Diagnostic 

(OBD) Readiness and DTCs Using I/M Data.
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orifice, such as 0.010 inch upstream of the purge valve for a pressurized system 

with a designed in-use operating pressure threshold in excess of 0.36 psi (10 inches 

water). Also, for the pressurized system, we asked for comment on a potential 

provision to require that the fuel tank vent to the canister at key off if the OBD 

system identifies a leak. In their comments manufacturers indicated concerns about 

the need for such provisions or their value in reducing emissions relative to current 

requirements. EPA believes both of these provisions merit further investigation, but 

at the present time we lack the data to assess the feasibility and emission reduction 

benefits associated with each approach and so are not taking action on them.

F. Finally, in the NPRM we sought input on whether the operation of a 

vacuum pump or similar device used to assist or supplement vehicle 

engine vacuum purge or any device otherwise used to enhance or 

control purge flows, rates, or schedules should be required to be 

monitored as part of OBD. In their comments the manufacturers 

indicated their view that this would be covered by current OBD 

provisions, and we are not taking further actions. Emissions Test Fuel 

In-use gasoline has changed considerably since EPA last revised 

specifications for the gasoline used in emissions testing of light- and heavy-duty

vehicles. Sulfur and benzene levels have been reduced and, perhaps most 

importantly, gasoline containing 10 percent ethanol by volume (E10) has replaced 

non-oxygenated gasoline (E0) across the country. This trend has had second-order 

effects on other gasoline properties. In-use fuel is projected to continue to change 

as refiners adjust their gasoline production to reflect the renewable fuel volumes 

required under the RFS2 program, as well as further sulfur reduction under the Tier 

3 rule.

408

 As a result, we are updating federal emission test fuel specifications to 

better match in-use fuel. The revised test fuel specifications apply for exhaust 

emissions testing, fuel economy/greenhouse gas testing, and emissions testing for 

non-exhaust emissions (with some exceptions discussed elsewhere in this preamble, 

e.g., for refueling tests in flex-fuel vehicles). The revised gasoline specifications, 

found at §1065.710 and discussed below, apply to emissions testing of light-duty

cars and trucks as well as heavy-duty gasoline vehicles certified on the chassis test, 

where the vehicles are certified to the Tier 3 standards.409

 

408 See 78 FR 49794 (August 15, 2013) for the latest renewable fuel requirements under the RFS2 

program.

409As discussed elsewhere in Section IV, we are also generally requiring the use of Tier 3 test fuel in 

conducting exhaust, evaporative, and refueling emissions testing of heavy-duty gasoline engines 

certified on an engine dynamometer. These could include engines installed in incomplete Class 2b 

and Class 3 vehicles and engines used in vehicles above 14,000 lb GVWR.
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1. Gasoline Emissions Test Fuel: Ethanol Content and Volatility

a. Emission Test Fuel Ethanol Content

In the NPRM, EPA proposed that the emissions test gasoline be changed 

from E0 to E15 as a forward-looking position based on indications following the 

2011 E15 waiver decision that the market would move in that direction.410 Since 

the time when we developed the proposal, several relevant factors have led EPA to 

reconsider that position, including limited proliferation on a national scale of 

stations offering E15 and the complexities E15 test fuel would introduce for longterm harmonization of the Tier 3 vehicle emission regulations with California’s 

LEVIII program (which uses E10 for emissions testing).

We received comments supporting use of E10 as emissions test fuel from 

the automotive and oil industries, as well as states and NGOs citing the fact that this 

was most representative of current market conditions. Other stakeholders involved 

in fuel marketing and distribution cited significant infrastructure cost and liability

concerns in making E15 widely available at existing stations. Ethanol industry

commenters generally supported E15 certification fuel as proposed, but provided no 

specific timeline on which this blend level would become representative of in-use 

fuel. The most recent surveys of the market show that E10 now comprises nearly 

100% of in-use gasoline, with very small amounts of E0 and E15 being sold in 

limited areas where there is specific interest.411 Based on this information and 

considering comments, EPA is finalizing E10 as the ethanol blend level in 

emissions test gasoline for Tier 3 light-duty and heavy-duty gasoline vehicles. We 

will continue to monitor the in-use gasoline supply and based on such review may 

initiate rulemaking action to revise the specifications for emissions test fuel to 

include a higher ethanol blend level. 

As discussed above in Sections IV.A.7.d (tailpipe emission testing) and 

IV.C.5.b (evaporative emission testing), we are requiring all light-duty and chassiscertified heavy-duty gasoline vehicles to be certified to Tier 3 standards on federal 

E10 test fuel. As described in those sections, EPA will accept emission certification 

test results performed according to CARB’s LEVIII procedures including CARB’s 

 

410 EPA issued a waiver allowing E15 to be introduced into commerce for use in MY 2001 and 

newer light-duty motor vehicles. On July 25, 2011, EPA finalized regulations to mitigate the 

potential for misfueling of vehicles, engines, and equipment not covered by the E15 waiver, i.e., MY 

2000 and older light-duty motor vehicles, all heavy-duty gasoline vehicles and engines, motorcycles, 

and all gasoline-powered nonroad products (which includes boats).410 Two of the required 

mitigation measures are a label for fuel pumps that dispense E15 to alert consumers to the 

appropriate and lawful use of the fuel and a prohibition on the use of E15 by consumers in vehicles 

not covered by the waiver, excluding flexible fuel vehicles (FFVs). For more details, see 76 FR 

44406 (July 25, 2011).

411 More detail on fuel survey data is available in Chapter 3 of the Regulatory Impact Analysis.
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E10 test fuel. Confirmatory and in-use exhaust or evaporative testing of vehicles 

certified on CARB’s E10 test fuel will be performed using that same test fuel 

through MY 2019. After MY 2019, EPA will continue the practice of accepting 

emission data at certification on the LEVIII test fuel; however confirmatory and inuse testing may be performed using Tier 3 E10 test fuel at the discretion of the 

Agency. 

b. Certification Fuel Volatility (RVP) Specification

In deciding to finalize E10 as the emissions test fuel it is appropriate to 

consider whether a change in the volatility of the test fuel is warranted, typically

expressed as in pounds per square inch (psi) Reid Vapor Pressure (RVP) or dry

vapor pressure equivalent (DVPE). The Clean Air Act (Section 211(h)(1)) sets a 

national limit on summertime RVP in northern conventional gasoline areas of 9.0 

psi to control ozone pollution. However, Congress included a waiver allowance 

(Section 211(h)(4)) granting an additional 1 psi RVP to 10% ethanol blends, 

meaning that E10 could have an RVP up to 10 psi in these conventional gasoline 

areas unless specifically prohibited by state or local rules. Under Section 211(h)(4), 

E15 is not covered by the waiver and thus is restricted to 9 psi nationwide.

The automakers submitted comments that recommended leaving the RVP of 

emissions test fuel at 9 psi on the basis that raising the specification to 10 psi would 

increase the stringency of the proposed evaporative emission standards 

significantly. We agree that the resulting increased vapor generation rates during 

the refueling test would increase emissions (by about 10 percent and during the hot 

soak, diurnal, canister bleed, and running loss tests by as much as 25 percent in 

total). While the likely increase in canister volume in response to higher 

certification fuel RVP would not be difficult for automakers to accommodate in 

most cases, there are additional uncertainties regarding cost and feasibility of 

strategies for removing the larger vapor loads from the canister during vehicle 

operation (vapor “purging”). Some vehicles have adequate engine vacuum 

available to accomplish the increased vapor purge, while others may require new or 

innovative approaches to increase purge volume or efficiency (as discussed in the 

evaporative emissions technology discussion in Section IV.C.3). 

Several other commenters, such as NGOs and environmental groups, 

supported setting certification gasoline RVP to 10 psi to be representative of the 

worst-case volatility vehicles may see in the market, making the test procedure 

more stringent than in the proposed program and further reducing evaporative 

emissions. 

Raising the certification test fuel RVP to 10 psi would also impact the 

equivalency of CARB and EPA hot soak plus diurnal evaporative emission test 

procedures. (California requires the use of 7 psi RVP test fuel, which, in 

conjunction with higher test temperatures, produces equivalent results to the federal 
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test procedures using 9 psi fuel.) If we were to adopt 10 psi test fuel, we would 

likely need to develop and adopt new test procedure adjustments in order to 

maintain the equivalency of CARB and EPA evaporative procedures (and allow 

reciprocal acceptance of test data generated under either agency’s program). 

In addition, the 1 psi RVP waiver for E10 does not apply to gasoline with 

higher ethanol levels; for example, under current regulations E15 is subject to an 

RVP limit of 9 psi. If EPA had adopted 10 psi test fuel in this rule and if gasoline 

with higher ethanol levels than E10 were to become commonly used nationwide, 

maintaining alignment with in-use fuel could necessitate a change in emissions test 

fuel back to 9 psi. 

A review of 2011 gasoline batch data submitted to EPA shows that just 

under half of summertime gasoline was conventional gasoline at 10 psi RVP. An 

additional third was RFG at approximately 7 psi RVP, with the remainder having 

intermediate RVPs under local volatility control programs. A volume-weighted 

average of these data is approximately 8.7 psi RVP. Thus, an emissions test 

gasoline volatility at 9 psi aligns well with the average nationwide in-use RVP 

today. In addition, virtually all of the areas that have elevated summertime ozone 

levels where excess evaporative VOC emissions would be of greatest concern 

already control in-use gasoline RVP to levels less than 9 psi. Furthermore, under 

section 211(a)(5), governors can request that the 1 psi waiver for E10 not apply in 

their state if it causes an emissions increase that contributes to air pollution. Any

state exercising this authority would have in-use E10 RVP levels limited to 9 psi.

After considering these technical and policy issues in the context of the 

information available and comments received, we conclude that the most 

appropriate approach is to set an RVP of 9 psi for Tier 3 emissions test fuel. 

c. Durability Test Fuel

EPA’s motor vehicle emissions standards typically require a level of 

performance over a specified test procedure, with emissions measured while the 

engine or the vehicle is operated using the specified test fuel and operated in a 

specified manner. The test fuel specifications typically apply for all emissions 

testing used to determine compliance with the standard, including emissions testing 

to obtain a certificate of conformity, as well as compliance testing for newly

produced or in-use engines or vehicles. While this test fuel is sometimes referred to 

as “certification fuel,” the test fuel specifications are not limited to certification 

related emissions testing, but also apply to compliance related emissions testing 

after the certificate of conformity has been issued. The certification process also 

typically involves a process to ensure that the emissions controls system is durable 

over the regulatory useful life of the vehicle or engine. This can involve long-term 

or accelerated aging of a vehicle or engine prior to emissions testing. The fuel used 

for such aging is commonly referred to as service accumulation or durability fuel, 
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and in many cases is specified as commercial gasoline that will be generally

available through retail outlets (§86.113-04(a)(3)), or in some cases may be 

specified as gasoline which contains ethanol in, at least, the highest concentration 

permissible in gasoline under federal law and that is commercially available in any 

state in the United States, such as for durability aging of evaporative emissions 

system (§86.1824-08(f)). EPA is not changing the specifications for fuel used 

during durability related aging that is part of the certification process. The 

regulatory changes in this final rule only apply to the test fuel used during 

emissions testing, both for purposes of certification and for later compliance related 

testing.

We are not changing the exhaust or evaporative durability fuel requirements 

outlined in the provisions of §86.113-04(a)(3), except to remove the minimum 

sulfur content (15 ppm) specified at §86.113-04(a)(3)(i). Those provisions require 

that “[u]nless otherwise approved by the Administrator, unleaded gasoline 

representative of commercial gasoline that will be generally available through retail 

outlets must be used in service accumulation.” We expect that manufacturers will 

use service accumulation fuels that are generally representative of the national 

average in-use fuels (or worst case for durability) during the model year which is 

being certified, including, for example, the ethanol content (for exhaust emissions), 

sulfur level, and fuel additive package. For exhaust emission bench aging 

durability programs as allowed under the provisions of §86.1823-08(d) and (e), the 

bench aging program should be designed using good engineering judgment to 

account for the effects of in-use fuels on exhaust emissions, including the effects of 

future in-use fuels on catalytic converters, oxygen sensors, fuel injectors, and other 

emission-related components. 

For evaporative emissions, durability fuel requirements are the same as for 

exhaust emissions (as outlined above), plus an additional requirement in the 

provisions of §86.1824-08(f), that the service accumulation fuel “contains ethanol 

in, at least, the highest concentration permissible in gasoline under federal law and 

that is commercially available in any state in the United States. Unless otherwise 

approved by the Administrator, the manufacturer must determine the appropriate 

ethanol concentration by selecting the highest legal concentration commercially

available during the calendar year before the one in which the manufacturer begins 

its mileage accumulation.” Thus, we expect that E15 service accumulation fuel will 

be used for whole vehicle evaporative durability programs. Similarly, evaporative 

bench aging durability programs allowed under the provisions of §86.1824-08(d) 

and (e), should be designed using good engineering judgment to account for the 

durability effects of in-use fuels on evaporative emissions, bleed emissions, and 

leakage emissions. 
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2. Other Gasoline Emissions Test Fuel Specifications

Where possible, we are changing test fuel specifications to be consistent 

with CARB’s LEV III gasoline test fuel specifications.412 In addition to the ethanol 

and volatility specifications discussed above, below is an overview of some of the 

key changes. Table IV-25 provides a summary of the new test fuel properties. For 

more information on how we arrived at the test fuel property ranges and ASTM test 

methods, refer to Chapter 3 of the RIA.

 Octane - lowering gasoline octane to around 87 (R+M)/2 to be 

representative of in-use fuel, i.e., regular-grade E10 gasoline. 

Manufacturers can continue to use high-octane gasoline for testing of 

premium-required413 vehicles and engines as well as for testing unrelated 

to exhaust emissions. Historically, the high octane rating of test fuel has 

not had any real emissions implications. However, as manufacturers 

begin introducing new advanced vehicle technologies (e.g., 

turbocharged/downsized), this may no longer be the case. For those 

vehicles where operation on high-octane gasoline is required by the 

manufacturer, we are allowing the manufacturer to test on a fuel with a 

minimum octane rating of 91 (R+M)/2 (in lieu of the 87 (R+M)/2 

specified for general test fuel). According to the regulations found at 

§1065.710(d), vehicles or engines are considered to require premium 

fuel if they are designed specifically for operation on high-octane fuel 

and the manufacturer requires the use of premium gasoline as part of 

their warranty as indicated in the owner’s manual. Cases where 

premium gasoline is not required but is recommended to improve 

performance would not qualify as a vehicle or engine that requires the 

use of premium fuel. For qualifying vehicles and engines, all emission 

tests must use the specified high-octane fuel. For vehicles and engines 

certified on high-octane gasoline, all EPA confirmatory and in-use 

testing would also be conducted on high-octane gasoline. All other test 

fuel specifications are the same as those described in Table IV-25. 

 Distillation Temperatures - adjusting gasoline distillation temperatures 

to better reflect in-use E10 gasoline. This includes minor T10, T90 and 

FBP adjustments based on AAM fuel surveys and refinery batch data. 

These data show that T50 varies widely in in-use fuel, from around 

150°F to 220°F. Adopting a wide specification range for test fuel may

have undesirable effects on consistency of results between facilities and

over time. Therefore, we have chosen a range of 190-210°F to maintain 

 

412 LEV III test procedures, including a description of test fuel, can be found at 13 CCR 1961.2.

413 Premium-required defined at §1065.710(d).
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some overlap with CARB’s specification of 205-215°F but extending 

somewhat lower to better capture federal in-use fuel. For more 

information on how we arrived at the distillation temperatures in Table 

IV-25, refer to Chapter 3 of the RIA. 

 Sulfur - lowering the sulfur content of test fuel to 8-11 ppm to be 

consistent with our new Tier 3 gasoline sulfur standards. The 10 ppm 

annual average sulfur standard for in-use gasoline standard is expected 

to result in two-thirds less sulfur nationwide so it is appropriate to lower 

the gasoline test fuel specification in concert.

 Benzene - setting a benzene test fuel specification of 0.5-0.7 volume 

percent to represent in-use fuel under the MSAT2 regulations.414 The 

MSAT2 standards, which took effect January 1, 2011, limit the gasoline 

pool to 0.62 volume percent benzene on average. 

 Total Aromatics - lowering the range of aromatics content in the test fuel 

to better match today’s in-use E10 gasoline, and narrowing the range to 

limit variability of results. Data from recent gasoline batch data as well 

as AAM surveys support a specification of 22-26 volume percent.415 

 Distribution of Aromatics – in addition to total aromatics and benzene, 

the updated test fuel requirements place boundaries on the distribution of 

aromatics by carbon number (i.e., prescribed volume percent ranges for 

each of C7, C8, C9, and C10+ hydrocarbons). There is evidence that the 

heaviest aromatics in gasoline contribute disproportionately to PM 

emissions, so compliance with emission standards should be 

demonstrated on fuel with a composition representative of in-use 

gasoline. For more information on the aromatics specifications, refer to 

Chapter 3 of the RIA. 

 Olefins - adjusting the olefins specification to a range of 4-10 volume 

percent to better match in-use E10 gasoline. 

 Other Specifications - adding distillation residue, total content of 

oxygenates other than ethanol, copper corrosion, solvent-washed gum, 

and oxidation stability specifications to better control other performance 

properties of test fuel. These specifications are consistent with ASTM’s 

D4814 gasoline specifications and CARB’s LEV III test fuel 

requirements.

 

414 72 FR 8434 (February 26, 2007).

415 More details on fuel property analysis are available in Chapter 3 of the RIA.
Page 284 of 529

 Updates to Gasoline Test Methods – updating some of the gasoline test 

methods previously specified in §86.113 with more appropriate, easier to 

use, or more precise test methods for ethanol-blended gasoline. Key

changes include replacement of ASTM D323 with ASTM D5191 for 

measuring vapor pressure; replacement of ASTM D1319 with ASTM 

D5769 for measuring aromatics and benzene; and replacement of ASTM 

D1266 with three alternative ASTM test methods (D2622, D5453 or 

D7039) for measuring sulfur. 
Page 285 of 529

Table IV-25. Gasoline Emissions Test Fuel Properties

Property Unit

SPECIFICATION

Reference Procedurea

General 

Testing

LowTemperature 

Testing

High Altitude 

Testing

Antiknock Index (R+M)/2 - 87.0 - 88.4

b 87.0 

Minimum

ASTM D2699 and 

D2700

Sensitivity (R-M) - 7.5 Minimum ASTM D2699 and 

D2700

Dry Vapor Pressure 

Equivalent (DVPE)

c,d kPa (psi) 60.0-63.4 

(8.7-9.2)

77.2-81.4

(11.2-11.8)

52.4-55.2 

(7.6-8.0) ASTM D5191

Distillatione

10% evaporated °C (°F) 49-60(120-140)

43-54 

(110-130)

49-60

(120-140)

ASTM D86

50% evaporated °C (°F) 88-99 (190-210)

90% evaporated °C (°F) 157-168 (315-335)

Evaporated final boiling

point °C (°F) 193-216 (380-420)

Residue milliliter 2.0 Maximum

Total Aromatic 

Hydrocarbons volume % 21.0-25.0

ASTM D5769

C6 Aromatics (benzene) volume % 0.5-0.7

C7 Aromatics (toluene) volume % 5.2-6.4

C8 Aromatics volume % 5.2-6.4

C9 Aromatics volume % 5.2-6.4

C10+ Aromatics volume % 4.4-5.6

Olefins5 mass % 4.0-10.0 ASTM D6550

Ethanol blended volume % 9.6-10.0 See §1065.710(b)(3)

Ethanol confirmatoryfvolume % 9.4-10.2 ASTM D4815 or 

D5599

Total Content of 

Oxygenates Other than 

Ethanolf

volume % 0.1 Maximum ASTM D4815 or 

D5599

Sulfur mg/kg 8.0-11.0 ASTM D2622, 

D5453 or D7039

Lead g/liter 0.0026 Maximum ASTM D3237

Phosphorus g/liter 0.0013 Maximum ASTM D3231

Copper Corrosion - No. 1 Maximum ASTM D130

Solvent-Washed Gum 

Content

mg/100 

milliliter 3.0 Maximum ASTM D381

Oxidation Stability minute 1000 Minimum ASTM D525

aASTM procedures are incorporated by reference in §1065.1010. See §1065.701(d) for other allowed procedures.

bOctane specifications apply only for testing related to exhaust emissions. For engines or vehicles that require the use 

of premium fuel, as described in paragraph (d) of this section, the adjusted specification for antiknock index is a 

minimum value of 91.0; no maximum value applies. All other specifications apply for this high-octane fuel.

cCalculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, using the following 

equation: DVPE (kPa) = 0.956∙pT - 2.39 (or DVPE (psi) = 0.956∙pT – 0.347. DVPE is intended to be equivalent to 
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Reid Vapor Pressure using a different test method.

d

Parenthetical values are shown for informational purposes only. 

eThe reference procedure prescribes measurement of olefin concentration in mass %. Multiply this result by 0.857 and 

round to the first decimal place to determine the olefin concentration in volume %. 

fThe reference procedure prescribes concentration measurements for ethanol and other oxygenates in mass %. Convert 

results to volume % as specified in Section 14.3 of ASTM D4815.

As mentioned earlier, we will continue to allow manufacturers to test 

vehicles on premium-grade gasoline should the vehicles require it. In addition, 

since we cannot predict all future changes in gasoline vehicle technologies and inuse fuels, we will allow vehicle manufacturers to specify an alternative test fuel 

under certain situations. Under this provision, if manufacturers were to design 

vehicles that required operation on a higher octane, higher ethanol content gasoline 

(e.g., dedicated E30 vehicles or FFVs optimized to run on E30 or higher ethanol 

blends), under 40 CFR 1065.701(c), they can petition the Administrator for 

approval of a higher octane, higher ethanol content test fuel if they can demonstrate 

that such a fuel would be used by the operator and would be readily available 

nationwide, vehicles would not operate appropriately on other available fuels, and 

such a fuel would result in equivalent emissions performance. For vehicles certified 

on high-octane, high-ethanol gasoline, all EPA confirmatory and in-use testing 

would also be conducted on high-octane, high-ethanol gasoline. This could help 

manufacturers who wish to raise compression ratios to improve vehicle efficiency

as a step toward complying with the 2017 and later light-duty greenhouse gas and 

CAFE standards. This in turn could help provide a market incentive to increase 

ethanol use beyond E10 and enhance the environmental performance of ethanol as a 

transportation fuel by using it to enable more fuel efficient engines. 

We received comments in general support of allowing certification on 

higher octane fuels if the vehicles require it, although some commenters believe that 

the criteria EPA is specifying for such an allowance are too severe. We have 

considered these comments, and as discussed in the Summary and Analysis of 

Comments document, we continue to believe that our approach is appropriate, and 

we are finalizing these provisions as proposed. 

3. Flexible Fuel Vehicle Exhaust Emissions Test Fuel 

We are also finalizing specifications for the fuel used in flexible fuel 

vehicles (FFV) exhaust emissions testing including certification testing. EPA is 

establishing specifications for FFV test fuel to resolve confusion and inconsistency

among FFV manufacturers in carrying out their certification and other testing 

requirements and to ensure that FFV emissions are appropriately controlled over the 

range of in-use fuels. The FFV exhaust emissions test fuel specifications will

phase in on the same schedule as the E10 standard gasoline test fuel specifications 

for light- and heavy-duty gasoline vehicles (described in Section IV.F.4). These 

FFV exhaust emissions test fuel specifications may be used voluntarily prior to 
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when they are required to be used. The base fuel stock used to formulate FFV 

exhaust emissions test fuel must comply with the specifications finalized today for 

the standard E10 emissions test fuel as described in preamble Sections IV.F.1 and 2. 

This practice avoids the need to specify the ranges for a number of fuel parameters 

as we have done for gasoline test fuel in Table IV-25 and helps to minimize the 

number of test fuels that a vehicle manufacturer must store. Denatured fuel ethanol 

(DFE) that meets the specifications discussed in preamble Section V.G. must be 

blended into this base fuel stock to attain an ethanol content of 80 to 83 volume 

percent in the finished test fuel. Commercial grade normal butane can be added as 

a volatility trimmer to meet a 6.0 to 6.5 psi RVP specification for the finished test 

fuel.

416

As an alternative to the use of DFE to manufacture FFV test fuel, neat 

(undenatured) fuel grade ethanol can be used. As an alternative to using a finished 

E10 standard gasoline test fuel in the manufacture of FFV test fuel, the gasoline 

blendstock used by the fuel provider to produce a compliant E10 test fuel can also 

be used to manufacture the FFV test fuel. This would allow ethanol to be blended 

only once to produce FFV test fuel. In such cases, a sample of the subject gasoline 

blendstock must be tested after the addition of ethanol to produce a finished 

standard E10 gasoline test fuel to demonstrate that the blend meets all of the 

requirements for standard gasoline test fuel described in Section IV.F.

The public comments were supportive of EPA establishing specifications for 

FFV exhaust emissions test fuel. However, some commenters stated that the 

ethanol content and RVP specifications for FFV exhaust emissions test fuel should 

be based on typical values for in-use E85.417 Automobile manufacturers 

commented that EPA should wait to finalize FFV test fuel specifications until a 

review of in-use E51-83 fuel quality can be completed in later 2013. They stated 

that this would allow the FFV test fuel specifications to be representative of the 

change to in-use “E85” composition since ASTM reduced the minimum ethanol 

concentration from 68 to 51 volume percent.

Substantial publicly available literature exists to demonstrate that the 

ethanol content of fuel used in FFVs has a significant effect on vehicle emissions. 

The effect of ethanol content on FFV emissions becomes more pronounced with 

increasing ethanol concentration. The current ASTM specification for E85 provides 

that the ethanol content of E85 may vary from 51 to 83 volume percent depending 

 

416 The specifications for commercial grade butane are contained in 40 CFR 80.82.

417 The term “E85” has historically been used to describe an ethanol blend for use in FFVs with a 

maximum ethanol content of 83 volume percent and satisfying other fuel parameter specifications 

established by ASTM International. ASTM D5798-13, “Standard Specification for Ethanol Fuel 

Blends for Flexible-Fuel Automotive Spark-Ignition Engines”. 
Page 288 of 529

on climactic conditions. 418 Consistent with our long standing policy regarding the 

exhaust emissions testing of FFVs, we continue to believe that FFVs must comply

with all emissions control requirements while using any fuel that they have the 

potential to operate on in-use. This ensures vehicles are designed and calibrated for 

emissions performance across the full range of potential in-use fuel formulations. 

FFVs are required to have exhaust emissions certification testing conducted using 

both E10 and FFV exhaust emissions test fuel to account for the effect on emissions 

of the full range of potential ethanol blend formulations. To ensure that FFV 

certification testing adequately accounts for in-use emissions performance, we are 

finalizing the ethanol content of FFV exhaust emissions test fuel at 81-83 volume 

percent as proposed. Exhaust emissions testing conducted using a fuel containing 

81-83 volume percent ethanol will provide results that represent the effect of 

ethanol on FFV emissions performance when this effect is most pronounced. The 

complimentary emissions certification testing required for FFVs on E10 will ensure 

that the effect on FFV emissions from the full range of potential in-use ethanol 

concentrations is represented. Given the need to ensure that FFV emissions 

certification testing is representative of the full range of potential in-use ethanol 

blends, it would be inappropriate to set the required ethanol concentration for FFV 

emissions test fuel based on typical in-use levels as suggested by some of the 

commenters.

Similarly, the RVP of FFV exhaust emissions test fuel must assure 

emissions performance over the range of in-use fuels. When ethanol and gasoline 

are blended to produce high level ethanol blends, the RVP can be and often is very

low. As a result, ASTM instituted a minimum RVP for E51-83 of 5.5 psi. Given 

that low volatility fuels can make the control of cold start emissions more 

challenging, we are finalizing the RVP of FFV exhaust emissions test to be near the 

minimum RVP that will be encountered in-use. The 6.0 to 6.5 RVP specification 

finalized today will help to ensure that FFVs are designed and calibrated to 

maintain their exhaust emissions performance across the range of in-use fuels. 

The levels of other fuel parameters for in-use E51-83 are determined by the 

levels of these parameters present in the gasoline blendstock used as diluted by the 

addition of ethanol. Therefore, we believe that requiring that the levels of these 

other fuel parameters present in FFV exhaust emissions test fuel be determined by

the dilution of the levels present in standard gasoline emissions test fuel 

appropriately reflects their potential effect on emissions performance. Given the 

considerations discussed above in determining the FFV exhaust emissions test fuel 

specifications finalized today, we do not believe that there would be a substantial 

 

418 ASTM International D5798-13, “Standard Specification for Ethanol Fuel Blends for FlexibleFuel Automotive Spark-Ignition Engines”. 
Page 289 of 529

benefit in waiting for the completion of the E51-83 fuel quality survey currently

underway to finalize FFV test fuel specifications. 

As discussed in preamble Section V.H., the Agency is also considering 

finalizing the in-use fuel quality standards for higher level ethanol blends on which 

we sought comment in the NPRM. These standards included an in-use RVP 

standard of 9.0 psi matching that of conventional gasoline. They also contained 

provisions to allow the production of high-level ethanol blends for use in FFVs 

from natural gasoline and other higher volatility components. Were we to finalize 

these in-use standards, we would also consider raising the RVP for the FFV exhaust 

emissions test fuel.

We are revising the definition of “alcohol” in 40 CFR part 600 to align with 

the change in the ASTM specification for in-use fuels. Under the revised 

regulation, we consider an alcohol-fueled vehicle to be one that is designed to 

operate exclusively on a fuel containing 51 percent or more ethanol or other alcohol 

by volume. This is not intended to change the applicability, procedures, or 

requirements for the fuel economy provisions in 40 CFR part 600.

4. Implementation Schedule 

As described earlier in this Section IV, we are establishing Tier 3 exhaust 

and evaporative emission standards. The changes in the specifications for test fuel 

apply to vehicles certified to these new standards. The program is designed to 

transition to the new test fuel during the first few years as the Tier 3 standards are 

phasing in. Testing requirement with the new Tier 3 test fuel starts with light-duty

vehicles certified to Tier 3 bin standards at or below Bin 70, and heavy-duty

vehicles certified to Tier 3 bin standards at or below Bin 250 (for Class 2b) and Bin 

400 (for Class 3). For light-duty vehicles, Table IV-26 below describes the 

implementation schedule of the new Tier 3 gasoline test fuels for each of the 

program elements in addition to the all the gasoline test fuel options available 

during the transition period. Table IV-3 below similarly describes the heavy-duty 

gasoline vehicle test fuel implementation schedule and gasoline test fuel options. 

The new Tier 3 PM requirements for both light-duty vehicles and heavy duty

vehicles which phase-in independent of other vehicle exhaust emission 

requirements must be met using the certification test fuel for meeting the

NMOG+NOX standards. 

Starting with model years 2020 for light-duty and 2022 for heavy-duty, all 

manufacturers will use the new test fuel for all exhaust emission testing (with the 

exception of small volume manufacturers and small businesses, which can delay

using the new test fuel for all vehicles until model year 2022). Manufacturers also 

need to comply with cold temperature CO and NMHC standards using the new test 

fuel for any models that use the new test fuel for meeting the light-duty Tier 3 

exhaust emission standards as indicated in the tables below. These same tests will
Page 290 of 529

also provide the basis for meeting GHG requirements under 40 CFR part 86 and 

fuel economy requirements under 40 CFR part 600, as described in the following 

section. 

Table IV-26. Exhaust Emissions Gasoline Test Fuels for LDVs, LDTs, and 

MDPVs

Emission Compliance 

Program

Test purpose: 

demonstration of 

compliance to the 

emissions 

standards: 

Test Cycles

FTP City/ HWFE/SFTP Cold CO 

and 

NMHC

High 

Altitude

Tier 2 Certification (1)(2)(3)(4) (1) (1)

Confirmatory and 

In-use

Certification fuel 

and/or (1)*

(1) (1)

Tier 3 Early Certification (1)**(2)***(3)(4) (1)**(3) (1)**(3)

2015 to 2017 Confirmatory and 

In-use 

Certification fuel (1)**(3) (1)**(3)

Tier 3 phase-in Certification (1)**(2)***(3)(4) (1)**(3) (1)**(3)

2017 to 2019 Confirmatory and 

In-use 

Certification fuel (1)**(3) (1)**(3)

Tier 3 complete Certification (3)(4) (3) (3)

2020+ Confirmatory and 

In-use

Certification fuel 

and/or (3)*

(3) (3)

Fuels: (1) Tier 2 (2) LEV II (3) Tier 3 E10 (4) LEV III E10

*EPA accepts the use of California certification fuels (or Tier 3 E10 for Tier 

2 certification) but manufacturer must comply on the program specific Federal fuel. 

EPA may perform or require manufacturer testing on the Federal fuel. 

**Fuel (1) only allowed for Bins 160, 125, 110, 85.

*** Fuel (2) only allowed for carryover SULEV 150k exhaust. 
Page 291 of 529

Table IV-27. Exhaust Emissions Gasoline Test Fuels for Heavy Duty Vehicles

Emission Compliance 

Program

Test purpose: 

demonstration of 

compliance to the 

emissions 

standards: 

Test Cycles

FTP City/ HWFE/SFTP High 

Altitude

Pre-Tier 3 Certification (1)(2)(3)(4) (1)

Confirmatory and 

In-use

Certification fuel 

and/or (1)*

(1)

Tier 3 Early Certification (1)** (3)(4) (1)**(3)

2016 to 2017 Confirmatory and 

In-use 

Certification fuel (1)**(3)

Tier 3 phase-in Certification (1)** (3)(4) (1)**(3)

2018 to 2021 Confirmatory and 

In-use 

Certification fuel (1)**(3)

Tier 3 complete Certification (3)(4) (3)

2022+ Confirmatory and 

In-use

Certification fuel 

and/or (3)*

(3)

Fuels: (1) Tier 2 (2) LEV II (3) Tier 3 E10 (4) LEV III E10

*EPA accepts the use of California certification fuels (or Tier 3 E10 for Tier 

2 certification) but manufacturer must comply on the program specific Federal fuel. 

EPA may perform or require manufacturer testing on the Federal fuel. 

**Fuel (1) only allowed for Bins 340, 395, 570, 630.

Additionally, heavy-duty gasoline engines (HDGEs) not subject to new Tier 

3 exhaust emission standards (those certified for exhaust emissions using an engine 

dynamometer) are required to be certified on Tier 3 fuel by MY 2022. Further 

discussion can be found in Section IV.C.4.c. 

For evaporative emission testing, manufacturers will need to use the new 

test fuel for any models that are to be certified to the Tier 3 evaporative emission 

standards. To the extent that these models are different than those used for exhaust 

emission testing with the new test fuel, manufacturers will need to do additional 

testing to demonstrate compliance with all applicable standards. They may 

alternatively use the new test fuel earlier than the regulations specify to avoid 

additional testing. We further require that manufacturers submit certification data 

based on the new test fuel to demonstrate compliance with refueling emission 

standards for any vehicles that are certified to the Tier 3 evaporative emission 

standards.
Page 292 of 529

5. Implications of Emission Test Fuel Changes on CAFE Standards, GHG 

Standards, and Fuel Economy Labels

a. Test Fuel

Under regulations in 40 CFR part 600, vehicles use the same test fuel in 

emission testing conducted for CAFE standards, greenhouse gas (GHG) emissions, 

and the fuel economy label as that used for emission testing for criteria pollutants. 

This includes the test fuel used for testing on all five cycles (FTP, highway fuel 

economy test (HFET), US06, SC03, and Cold FTP). In the Tier 3 NPRM, EPA 

proposed a change in emissions test fuel used to determine compliance with criteria 

pollutant standards and this test fuel change would also apply to CAFE and GHG 

standards and the fuel economy label such that a common test fuel under 40 CFR 

part 600 was retained. At the same time, EPA indicated its commitment to the 

principle that the change in test fuel would not affect the stringency of the CAFE or 

GHG standards and that the labeling calculations would be updated in a future 

action to reflect the change in test fuel properties.

The NPRM indicated that more data and time were needed to assess the 

effects on stringency and implementation of these programs. While EPA’s initial 

review of available data suggested that the change in test fuel would not impact the 

GHG standards, more time and data were needed to confirm this initial view 

regarding the GHG standards and to determine what adjustments if any would need 

to be made to the CAFE program and fuel economy label calculation procedures to 

account for the change in test fuel. EPA indicated we would defer action on 

appropriate adjustments, if any, for the GHG and CAFE programs until data were

available to assess how the difference in the fuel properties (Tier 3 fuel compared to 

Tier 2 fuel) would impact the stringency of the CAFE and GHG standards for Tier 3 

technology vehicles and the calculations for the fuel economy label. EPA indicated 

that any adjustments or changes in the regulatory text would be done through a 

future action.

Manufacturers commented that EPA should take action on the necessary

adjustments to compliance calculations as part of the Tier 3 final rule. The 

methodologies for addressing some elements of the changes in fuel properties such 

as the difference in energy density are already addressed in the regulation. One key

element, the “R” factor found in the equation of 40 CFR 600.113-12(h)(1) is 

intended to capture inefficiencies and differences in how vehicles respond to 

changes in the energy content of the fuel. This factor is empirically based, 

developed using vehicle test data. This value is presently set at 0.6 and is shown in 

the denominator of the aforementioned equation. While there has been some data 

evaluated to assess the impact of changing the emission test fuel on the “R” factor, 

EPA did not propose a value in the NPRM and specifically stated that we would 

continue to investigate this issue and if necessary address it as part of a future 

action, as opposed to changing it in the Tier 3 final rule. Furthermore, as discussed 
Page 293 of 529

above, there is a need for more data to fully understand how other changes in 

certification fuel for Tier 3, such as the octane specification, may affect the 

stringency of the CAFE and GHG standards which were based on Tier 2 emission 

fuel, as well as any implications for the fuel economy label. These potential effects 

are best understood using emission data generated on Tier 3/LEV III vehicles tested 

on both Tier 3 and Tier 2 test fuel.

In addition, the manufacturers commented that even with the use of 

“analytically derived data” as permitted under current EPA regulations and 

guidance419, EPA should finalize an appropriate test procedure adjustment in the 

Tier 3 rulemaking, including adoption of an “R” factor of 1.0, and should allow 

manufacturers the option of using Tier 2 fuel for CAFE, GHG, and fuel economy

labeling at least through MY2019 to provide time for adjusting to the new test fuel. 

In the NPRM, EPA indicated that we would not be changing the “R” factor 

or implementing other adjustments or changes in the regulatory text in the FRM. In 

follow-up meetings with the manufacturers, we expressed a willingness to consider 

permitting GHG and CAFE to continue on Tier 2 fuel until the future rulemaking

action to address the “R” factor and other potential changes was complete and in 

effect. The manufacturers responded that under this approach the existing 

regulations would require a significant amount of additional emission testing for 

any model certified to the Tier 3/LEVIII exhaust emission standards before the 

future rulemaking is completed and in effect.420 This is because Tier 3 test fuels 

would be used in emission data vehicles (EDVs) evaluated for compliance with Tier 

3 criteria pollutant standards, but these same EDVs would also have to be tested on 

Tier 2 fuel for GHG, fuel economy label, and CAFE program data purposes. Also, 

while Tier 2 fuel would apply to EDVs and fuel economy data vehicles (FEDVs) 

evaluated for fuel economy label, CAFE program data values, and compliance with 

GHG standards, these same FEDVs would have to be retested on Tier 3 fuel to 

show compliance with the Tier 3 criteria pollutant standards. This additional testing 

would also extend to in-use verification program (IUVP) testing under 40 CFR 

§86.1845 through §86.1853.

In response to the concerns expressed by the manufacturers, EPA has 

identified five interim changes to existing regulations to both clarify testing 

requirements and to provide the manufacturers a reasonable opportunity to continue 

to test for CAFE, GHG, and labeling purposes on Tier 2 test fuels for each EDV 

and FEDV until such time as EPA determines appropriate adjustments, if any, 

related to a change to Tier 3 test fuels. EPA believes these changes can be 

 

419 See 40 CFR §600.006-08(e) and EPA guidance letter CD 12-03, February 27, 2012 and CCD-04-

06, March 11, 2004, available at http://iaspub.epa.gov/otaqpub/. 

420 This could start as early as the 2015 MY when the LEV III program begins to phase-in.
Page 294 of 529

implemented without impacting the integrity of the testing conducted for the criteria 

pollutant, CAFE, and GHG standards or values generated for determination of fuel 

economy labels. It is very important to note that the emission test data generated by

these early Tier 3/LEVIII vehicles covering both Tier 2 and Tier 3 test fuel will 

provide data needed to assess the “R” value and the impact of the fuel change on 

the stringency of the CAFE and GHG standards, and the calculations for the fuel 

economy labeling program. These data will be instrumental in developing any

appropriate adjustments to maintain equivalent stringency for the CAFE and GHG 

standards and to update the fuel economy labeling calculations, as needed. At the 

present time, EPA expects to have the needed data in early to mid 2015 and will 

then be in a position to conduct a thorough assessment of the impacts of different 

emission test fuels on Tier 3/LEV III vehicles and develop any appropriate 

adjustments and changes, in consultation and coordination with NHTSA. 

These interim changes which are presented below and shown in Table 

IV-28, apply only to vehicles certified to the Tier 3 and/or LEV III exhaust 

emission standards in the model years before the future action mentioned above 

takes effect. These are reflected in 40 CFR 80.600.113.

1. For any given EDV or FEDV, our regulations will require that testing 

related to CAFE and GHG standards and the fuel economy label must still be done 

on Tier 2 fuel even if criteria pollutant testing is done on Tier 3 or LEV III fuel. 

The “R” value used in the fuel economy equation would remain at 0.6 until any

change is made in a future rulemaking.

2. The requirement continues that FEDVs are expected to meet the criteria 

pollutant emission standards. As a flexibility, rather than requiring FEDVs to retest 

on Tier 3 fuel to show that they pass the criteria pollutant emission standards, we 

are providing in the regulations that FEDVs may meet these standards using Tier 2 

fuel on each of the five cycles (as applicable) or be subject to retesting and passing 

on Tier 3 fuel if they do not meet requirements on Tier 2 fuel or otherwise do not 

comply with 40 CFR 86.1835-01(b) and 40 CFR 600.008(b). In these 

circumstances, assuming a retested vehicle meets criteria pollutant standards on 

Tier 3 fuel, the emissions results on the Tier 2 fuel will still be used for CAFE, 

GHG, and fuel economy labeling purposes. Retesting on Tier 3 fuel is only required 

for those cycles where the FEDV did not meet the criteria pollutant standards on 

Tier 2 fuel.

3. As a flexibility, if EDV testing is conducted on Tier 3/LEV III fuel for 

criteria pollutants (all 5 cycles), then we are requiring the EDV testing to be

conducted on Tier 2 fuel for only 2 cycles (FTP and HFET) for GHG and CAFE 

purposes. These emission results on Tier 2 fuel are expected to meet the Tier 3 

criteria pollutant standards. Our regulations then require manufacturers to use 

these EDV Tier 2 fuel test results (FTP and HFET) for the CAFE, and GHG 

standards. The EDV Tier 2 fuel test results (FTP and HFET) would also be used for 
Page 295 of 529

fuel economy label calculations except in rare cases where the EDV does not pass 

the litmus test or if the manufacturer voluntarily elects to use the vehicle specific 5-

cycle method to determine fuel economy label values. In those two cases, the EDV 

would need to be tested on Tier 2 test fuel on each of the five cycles.

4. As a flexibility, during the interim model years, manufacturers may use 

either Tier 2 or Tier 3/LEVIII test fuel emission results to conduct the litmus 

evaluations for fuel economy labeling under 40 CFR 600.115-11. All emission 

results for the five tests involved used must be from the same test fuel. EPA 

believes this is appropriate since the litmus evaluation is based on a comparison of 

the percent differences of 2 and 5 cycle values rather than absolute differences in 

the values. If a manufacturer chooses to conduct the litmus evaluation using LEVIII

fuel, the cold FTP test must still use Tier 3 fuel. In the situation where the 

manufacturer uses Tier 3/LEV III test fuel for the litmus test the R-factor will be 

0.6. EPA will provide guidance on determining the values for the other fuel quality

parameters needed for the fuel economy calculations when Tier 3/LEVIII fuel is 

used. 

5. Exhaust emission testing for IUVP for GHGs shall be conducted using 

the same test fuel as used for criteria pollutant certification, unless the manufacturer 

uniformly elects to conduct its IUVP GHG testing on Tier 2 fuel. This relieves the 

need to conduct IUVP testing for criteria pollutants on Tier 3 fuel and GHG testing 

on Tier 2 fuel. EPA believes this is an acceptable interim regulatory flexibility, 

since the IUVP testing for GHGs does not involve the IUCP provisions of 40 CFR 

86.1846-01.

Table IV-28: Interim Testing Requirements for EDVs and FEDVs on Tier 3 

and Tier 2 Test Fuel

Criteria 

Pollutant 

(EDVs)

GHG/Label/CAFE Litmus IUVP

(EDVs and FEDVs) (Tier 2 

fuel)

Calculation

Tests/Cycles 5-cycle 5-

cycle

2- cycle 

(CAFE/GHG/label)

5-cycle Criteria

Pollutant

GHG*

(label)

Test fuel 

requirements

Tier 3

fuel or 

other 

transition 

option**

Tier 2 

fuel

Tier 

2 fuel

Tier 3 fuel Tier 2 or 

Tier 3 fuel

Tier 3 

fuel

Tier 2 

fuel
Page 296 of 529

FTP X X X Show 

criteria 

pollutant 

standards 

are met 

using Tier 

2 fuel or 

must retest 

on Tier 3 

fuel

Use 5-

cycle Tier 

3 fuel or 

Tier 2 fuel 

test results

X X

HFET X X X X X

US06 X X X

SC03 X X

Cold FTP X X

* Manufacturer may uniformly elect to use Tier 2 fuel results to meet the IUVP GHG requirements or rely on Tier 3 results.

** California Phase 2 fuel is only permitted for GHG/Label/CAFE and Litmus assessments for vehicles certified for criteria 

pollutants in the Tier 3 program using carryover data from CARB LEV II certifications such as SULEVs and PZEVs.

Manufacturers may use LEVIII fuel (California Phase 3) in lieu of Tier 3 

fuel, but any cold FTP testing must be done using Tier 3 Cold FTP fuel. LEV III 

fuel is 7 RVP E10, Tier 3 fuel is 9 RVP E10, and Tier 2 fuel is 9 RVP E0. 

Manufacturers have presented two points of view with regard to when the 

potential new requirements (including a revised “R” factor and other possible test 

procedure changes/adjustments related to CAFE, GHG, and fuel economy labeling) 

should take effect once the future rulemaking action mentioned above is complete. 

Some have stated that use of the new provisions should be available for use as soon 

as possible after the rule is completed. This would minimize the need for any future 

duplicate testing and put manufacturers on course for fully aligning with the new 

requirements quickly. Others have asked that there be lead time provided before 

the application of the new requirements becomes mandatory. The manufacturers 

have expressed concern that the use of the new requirements more quickly by one 

manufacturer versus another could create a competitive imbalance. At the same 

time, manufacturers do not necessarily want to be forced to certify all products to 

the new requirements by a cut-off date (e.g., 2020 model year) without EPA 

consideration of phase-in or phase-out provisions and data carryover. 

EPA understands the manufacturers’ various issues and concerns in this 

area. Based on the information available at this time, EPA is expecting to allow the 

optional use of any future adjustments for compliance calculation and labeling 

purposes as soon as the future rule mentioned above becomes effective. 

Furthermore, we expect that the mandatory use of any such new adjustments with 

all Tier 3 certifications would be required for the 2020 MY. These initial timing 

projections are subject to revision based on timing of the completion of the future 

action and the data and record developed in that future rulemaking. 
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b. Useful Life for GHG Standards

As stated above, EPA is committed to retaining equivalent stringency for 

GHG emissions compliance beginning in MY 2017. We need more emissions test 

data to better understand the GHG emission impacts of Tier 3 fuel in Tier 3 

technology vehicles. However, we believe that certifying a vehicle to a longer 

useful life for any emission constituent would have only a beneficial effect on 

emissions. To address potential concerns about changes in the stringency of the 

GHG standards resulting from a longer useful life, we are not requiring a longer 

useful life for GHG emission standards, although manufacturers can optionally

certify GHG emissions to a 150,000 mile, 15 year useful life.

6. Consideration of Test Fuel for Nonroad Engines and Highway

Motorcycles

As described earlier in Section IV.F., we are adopting new specifications for 

the gasoline emissions test fuel used for testing highway vehicles subject to the Tier 

3 standards. Earlier in the development of this rulemaking, EPA also considered 

changing the test fuel specifications for other categories of engines, vehicles, 

equipment, and fuel system components that use gasoline. These include a wide 

range of applications, including small nonroad engines used in lawn and garden 

applications, recreational vehicles such as ATVs and snowmobiles, recreational 

marine applications, and highway motorcycles. While engines in some of these 

categories employ advanced technologies similar to light-duty vehicles and trucks, 

the vast majority of these engines employ much simpler designs, with many of the 

engines being carbureted with no electronic controls. Because of the lower level of 

technology, emissions from these engines are potentially much more sensitive to 

changes in fuel quality.

EPA is not applying the new emissions test fuel specifications to these other 

categories of engines, vehicles, equipment, and fuel system components. In 

discussing the potential change in test fuel specifications with the large number of 

businesses potentially impacted by such a change, many companies supported such 

a change. However, a number of manufacturers raised concerns about the level of 

ethanol in the new fuel, the cost of recertifying emission families on the new fuel, 

the impact on nationwide product offerings, and the cost impact of complying with 

the existing standards on the new test fuel. EPA believes it is important that the test 

fuel for these other categories reflect real-world fuel qualities but has elected to 

defer moving forward now pending additional analysis of the impacts of changing 

the test fuel specifications for the wide range of engines, vehicles, equipment and 

fuel system components that could be impacted. These impacts include the impact 

on the emissions standards, as well as the other issues raised by the manufacturers. 

EPA plans to explore such a change in a separate future action. 
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While we are not changing the test fuel specifications for these other types 

of vehicles and engines, we are updating the reference standards associated with 

specific parameters and making minor adjustments to calculation methods. For 

certified engines and vehicles that have already been using the test fuel specified in 

§1065.710, we are clarifying that the RVP is calculated using the same equation 

described above for the new fuel specified for Tier 3 vehicles. We are also taking 

the opportunity to align and update test methods for the various gasoline test fuels 

in 40 CFR part 86. Specifically, we are revising §86.113 and §86.213 to (1) use 

both ASTM D2699 and ASTM D2700 for octane measurements involving both 

research and motor octane specifications (including octane sensitivity), (2) use 

ASTM D2622 for all sulfur measurements, which is widely used and provides 

superior results compared with the methods that have been referenced in the 

regulations, (3) use ASTM D5191 for measuring fuel volatility, including the 

calculation described above. We are also updating the regulations to reference a 

newer version of the following currently referenced procedures: ASTM D86, 

ASTM D1319 ASTM D2699, ASTM D3231, and ASTM D3237. All these changes 

and updates align with fuel specifications in 40 CFR part 1065.

7. CNG and LPG Emissions Test Fuel Specifications

There are currently no sulfur specifications for the test fuel used for 

certifying natural gas (CNG) vehicles. There is also no sulfur specification in 

§86.113 for the test fuel used for certifying liquefied petroleum gas (LPG) light 

duty vehicles. The LPG certification test fuel for heavy-duty highway engines and 

for nonroad engines in §1065.720 includes an 80 ppm maximum sulfur 

specification. We requested comment on the appropriateness of changing §86.113 

to reference 40 CFR part 1065 for all natural gas and LPG test fuels. We further 

requested comment on amending these specifications to better reflect in-use fuel 

characteristics, and in particular on the appropriateness of aligning the sulfur 

specifications with those that apply for gasoline test fuel. We noted that changing 

the sulfur specifications would depend on establishing that the new specification is 

consistent with the range of properties expected from in-use fuels.

The Alliance of Automobile Manufacturers (the Alliance) stated that EPA 

should adopt a 10 ppm maximum sulfur specification for CNG and LPG vehicle 

certification test fuels. They also stated that §86.113 should reference part 1065 for 

CNG and LPG test fuels (for light and heavy duty vehicles). The American 

Petroleum Institute (API), the Association of Fuel and Petrochemical Manufacturers 

(AFPM), and several individual refiners stated that EPA should not establish new 

sulfur standards for CNG and LPG vehicle certification test fuels until additional 

data are available on the sulfur content of in-use CNG/LPG fuels. The National 

Propane Gas Association (NPGA) stated that they are opposed to a change in the 

sulfur specifications for LPG vehicle certification test fuels given that they are 

unaware of any issue that would warrant such a change. 
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As discussed in Section V.J. of today’s preamble, additional time is needed 

for EPA to work with industry to collect data on current CNG/LPG sulfur content, 

to determine whether additional control of in-use CNG/LPG sulfur content is 

needed, and to evaluate the feasibility and costs associated with potential additional 

sulfur controls. Therefore, we are deferring finalizing in-use quality and 

certification test fuel specifications for CNG and LPG at this time.

G. Small Business Provisions

We are adopting special flexibility provisions for small businesses that are 

subject to the Tier 3 emissions standards. Such businesses are typically vehicle 

manufacturers, independent commercial importers (ICIs), or alternative fuel vehicle 

converters. We are also providing Tier 3 flexibility to companies that, though they

may not meet the eligibility requirements for small businesses, sell less than 5,000 

vehicles per year in the United States, and thus qualify as small volume 

manufacturers (SVMs). These companies and small businesses typically face 

similar challenges in implementing new EPA vehicle standards.

As in previous vehicle emissions rulemakings in which we have provided 

such flexibilities, our reason for doing so is that these entities generally have more 

implementation difficulty than larger companies. Small companies generally have 

more limited resources to carry out necessary research and development; they can 

be a lower priority for emission control technology suppliers than larger companies; 

they have lower vehicle production volumes over which to spread compliance costs; 

and they have a limited diversity of product lines, which limits their ability to take 

advantage of the phase-in and averaging provisions that are major elements of the 

Tier 3 program.

We proposed small business provisions largely based on the 

recommendations of the Small Business Advocacy Review (SBAR) Panel,

described in Section XIII.C of the Notice of Proposed Rulemaking (NPRM). We 

proposed provisions for additional lead time, reduced testing requirements, and 

opportunities for hardship relief to help small entities to leverage technological 

developments by others and to spread the availability of needed engineering, 

supplier, and capital resources. Based on the comments we received, we have 

improved on the proposed provisions in the final rule as described in detail below.

1. Lead Time and Relaxed Interim Standards

We proposed that small businesses and SVMs be allowed to postpone 

compliance with the standards and other Tier 3 requirements, including use of the 

new certification test fuel, until model year (MY) 2022. For MY 2022 and later,

they would be subject to the same Tier 3 requirements as other manufacturers, 

including the declining fleet average NMOG+NOx standards and the fully phased

in 30 mg/mi FTP standard for MYs 2025 and later. We requested comment on 
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adopting relaxed FTP NMOG+NOx standards for small companies in the light-duty

market segment, noting that LEV III provides light-duty SVMs with relaxed FTP 

NMOG+NOx standards of 125 and 70 mg/mi in MYs 2022 and 2025, respectively.

We did not receive comments from non-SVM small businesses subject to 

the Tier 3 vehicle standards about our proposed small entity phase-in provisions. 

However, we received comments from SVMs, as well as the Alliance of 

Automobile Manufacturers and the Association of Global Automakers, arguing that 

the proposed phase-in did not provide adequate lead time relief for SVMs, and that 

the long-term Tier 3 standards for light-duty vehicles are not technologically 

feasible for SVMs. They highlighted the ability of large manufacturers to offset 

high emissions from high-performance, luxury models by averaging with their lowemitting models, while competing SVM products must be designed to actually

achieve low emissions while still meeting customers’ performance expectations. 

Their limited production can also result in emission control technology suppliers 

placing a lower priority on SVM orders than on those of larger, high-volume 

manufacturers. 

Because of these factors, SVMs suggested that their companies meet a 

slightly more stringent NMOG+NOX standard (125 mg/mi) than what we proposed 

for SVMs in the early years of the program, and a permanently relaxed standard of 

51 mg/mi beginning in MY 2022. Ferrari suggested a compliance schedule for 

SVMs similar to the California LEV III program, with either a permanently relaxed 

standard (matching the California LEV III 70 mg/mi long-term standard) or a delay

until MY 2030 to meet the primary 30 mg/mi Tier 3 standard (when they suggest 

that SVMs could potentially comply). CARB comments supported Tier 3 adoption 

of its LEV III provisions for SVMs, including the long-term 70 mg/mi standard 

beginning in MY 2025. VNG, a natural gas fuel network provider, commented that 

gaseous-fuel small-volume test groups should be given extended phase-in 

opportunities identical to those proposed for SVMs, regardless of company size. As 

justification, VNG pointed to challenges unique to converting vehicles to operate on 

natural gas: thermal management of direct injection fueling and engine oil systems, 

adaptation of gasoline direct injection (GDI) controls to natural gas port fuel 

injection, and improvement of turbocharger response times. 

After considering the comments, we agree with SVMs that their unique 

logistical and technological challenges, especially in the later years of the primary

FTP NMOG+NOx standards phase-in schedule, warrant a significant period of 

relaxed standards for these manufacturers. However, we have found no 

fundamental reason why, given sufficient lead time, all manufacturers, regardless of 

company size and vehicle characteristics, will not be able to meet the Tier 3 

standards. Thus, we are finalizing an optional program for SVMs, available to nonSVM small businesses as well, under which they can choose an alternative 3-stage 

FTP NMOG+NOx fleet average standard phase-in schedule: an initial standard of 
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125 mg/mi for MYs 2017 through 2021, a more stringent standard of 51 mg/mi for 

MYs 2022 through 2027, and the final Tier 3 standard of 30 mg/mi thereafter.

Because companies choosing this 3-stage compliance option are certifying 

to Tier 3 bin standards in MY 2017, we are requiring that other exhaust emissions 

standards, including SFTP and PM standards, apply for their vehicles as well, to the 

same degree and on the same schedule as for other manufacturers. Application of 

evaporative emissions and onboard diagnostics (OBD) standards, on the other hand, 

is not affected by choice of the 3-stage compliance option for the FTP 

NMOG+NOx standards, and small companies may separately choose to delay

compliance with evaporative emissions and OBD standards (except as noted in 

Section IV.G.3) until MY 2022, as proposed. In addition, small companies 

choosing the 3-stage compliance option may delay the longer useful life and new 

test fuel requirements for exhaust emissions standards until MY 2022 to align these 

changes with the 3-stage schedule. This option would not preclude use of other 

applicable small entity flexibility provisions discussed in this subsection.

Although we are adopting this revised implementation schedule for SVMs 

and small businesses, we believe the proposed approach of allowing postponement 

of Tier 3 compliance until MY 2022 may be useful for small companies needing 

more lead time to begin certifying Tier 3 vehicles. Therefore we are finalizing the 

proposed approach as an additional but separate option for such companies, 

including SVMs, ICIs, and alternative fuel vehicle converters. Furthermore, 

because the optional 3-stage SVM implementation schedule, and the record of 

comments that prompted it, are specific to the light-duty sector, we are not 

extending it to heavy-duty vehicles and instead are finalizing only the proposed 

approach of allowing postponement of Tier 3 compliance until MY 2022 for any

SVMs and small businesses in the heavy-duty sector.

Companies that take advantage of one of the SVM and small business 

implementation schedule provisions in either the light-duty or heavy-duty sector are 

not allowed to generate or use Tier 3 exhaust emissions credits in that sector while 

or before they are subject to significantly less stringent standards than other 

manufacturers. That is, they cannot earn or use Tier 3 exhaust emissions credits 

before MY 2022 under the 3-stage light-duty SVM revised implementation 

schedule, and they also cannot do so before MY 2022 if they are using the 

postponed compliance schedule that we proposed, unless they choose to end their 

use of these SVM implementation options earlier than MY 2022.

We disagree with VNG’s assessment that small-volume test groups of large 

manufacturers should have until 2022 to comply with Tier 3. The technical 

challenges outlined by VNG have to do with converting gasoline vehicles to run 

reliably and durably on natural gas. Although these conversion challenges may be 

exacerbated for the new generation of turbocharged GDI vehicles, we have no 

evidence or comments from a vehicle manufacturer indicating that meeting Tier 3 
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standards is significantly more difficult for natural gas vehicles than for gasoline 

vehicles. Note that we are providing some relief for small volume test groups in the 

form of assigned deterioration factors (discussed below), but not because of 

feasibility concerns. Rather, we believe that assigned deterioration factors provide 

a sufficient alternative to the extensive process of developing a unique factor for 

each low-volume vehicle model. We find no justification to delay compliance with 

Tier 3 standards for larger manufacturers’ low-volume models as requested by

VNG.

2. Assigned Deterioration Factors

In Tier 3 as in past programs, manufacturers must demonstrate compliance

with emissions standards throughout the vehicle’s useful life. This is generally

done by testing vehicles at low mileage and then applying a deterioration factor to 

the measured emissions levels. The deterioration factors are determined by testing

emissions control systems before and after an aging process. In the past we have 

allowed small entities to use deterioration factors assigned by EPA instead of 

performing the extended testing, and we proposed to do so again for demonstrating 

compliance with Tier 3 exhaust and evaporative emissions standards. We did not 

propose specific assigned deterioration factors, but noted that the proposed delay in 

the small entity compliance schedule to MY 2022 would allow sufficient

deterioration data from large manufacturers to accumulate for timely development 

of these factors.

We are adopting the assigned deterioration factor provisions for small 

businesses and SVMs (as well as for small volume test groups), as proposed. 

Commenters expressed support, and asked that the Agency commit itself to keeping 

these factors up to date as durability data accumulates. In response, we can state 

that we are committed to periodically updating and publishing these assigned 

deterioration factors. Given that SVMs will be allowed to use the revised 

implementation schedule described above, starting in MY 2017, it becomes 

necessary to consider assigned deterioration factors in stages. Because there may

not be a sufficient base of accumulated durability data on Tier 3 vehicles by MY 

2017, we expect that the current set of assigned factors based on Tier 2 vehicles 

may continue in place for some time, noting that the MY 2017-2021 SVM fleet 

average of 125 mg/mi is not too much different from the average of today’s Tier 2 

vehicle emissions. By MY 2022, when the SVM NMOG+NOx fleet average 

standard drops to 51 mg/mile, we expect to have new assigned factors available. 

We note that small businesses and SVMs may also, with advance EPA approval, 

use deterioration factors developed by another manufacturer (40 CFR 86.1826-

01(b)).
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3. Reduced Testing Burden and OBD Requirements

Under our existing regulations, manufacturers must perform in-use testing 

on their vehicles and demonstrate that their in-use vehicles comply with the 

emissions standards. These regulations provide for reduced levels of testing for 

small companies with annual sales under 15,000, and for no in-use testing for those 

with annual sales up to 5,000. We received no adverse comments on our proposal 

to continue this approach in Tier 3, and are retaining it.

As described in Sections IV.A and IV.B, we are requiring manufacturers to 

test for PM emissions from vehicles of all fuel types, a change from previous 

practice in which non-diesel vehicles could be waived from PM testing. However, 

we proposed and have decided to continue the PM testing waiver in Tier 3 for small 

businesses and SVMs. In lieu of testing, these companies are required to make a 

statement of compliance with the Tier 3 PM standards, and their vehicles are still 

subject to the standards. We may however measure PM emissions to determine 

compliance in EPA confirmatory or in-use testing.

We proposed to apply CARB’s OBD requirements to Tier 3 vehicles, except 

that small alternative fuel vehicle converters would be allowed to instead meet our

existing OBD requirements (40 CFR 86.1806-05). The natural gas fuel network 

provider VNG objected that the proposed exception disadvantages larger vehicle 

manufacturers and should be made equally available to all vehicle manufacturers’ 

small volume test groups. We expect that larger manufacturers wishing to produce 

alternative fuel vehicles will be familiar with CARB’s OBD requirements and wellpositioned to implement these requirements in Tier 3. We note that larger OEMs 

themselves did not request to be covered by an extension of this provision. 

We are finalizing the exception to the Tier 3 OBD requirements as 

proposed. Note that the optional delay in Tier 3 implementation until MY 2022 that 

is available to small businesses, discussed above, includes a delay in the Tier 3 

OBD requirement to MY 2022, as proposed, except that vehicles already meeting 

this requirement in MY 2017 must continue to do so in subsequent years. We are 

also adopting this Tier 3 OBD delay to MY 2022 for small companies taking 

advantage of the revised light-duty 3-stage implementation schedule discussed 

above, even though other Tier 3 requirements start for them in MY 2017, in order to 

avoid overburdening these manufacturers with multiple sets of new OBD design 

constraints.

4. Hardship Relief

We proposed and are adopting provisions for small businesses and SVMs in 

hardship situations to apply for additional time to meet the Tier 3 standards. Such 

appeals will need to include evidence that the noncompliance would occur despite 

the manufacturer's best efforts to comply, and that severe economic hardship would 
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occur if the relief is not granted, though the company need not show that its 

solvency will be in jeopardy without the relief. (This showing is required in other 

EPA programs granting hardship relief under 40 CFR 1068.250.) The duration of 

relief will be established on a case-by-case basis for Tier 3 and is not being limited 

by regulation. Commenters supported these proposed provisions, within the context 

of a revised approach to SVM lead time, discussed above.

5. Eligibility for the Flexibilities

As proposed, we are using the federal Small Business Administration (SBA) 

criteria to define small businesses eligible for the special provisions. SBA defines 

small business vehicle manufacturers as those with less than 1,000 employees, and 

small business ICIs and alternative fuel vehicle converters are evaluated using SBA 

criteria based on annual revenues. See Section IV.H.3 for a discussion of additional 

provisions that apply specifically to ICIs. Also, as proposed, we are defining SVMs 

in 40 CFR 86.1838-01 for purposes of Tier 3 as companies with nationwide annual 

U.S. sales volumes at or below 5,000 vehicles, though the 15,000 vehicle threshold 

used in Tier 2 continues to apply in a few regulatory provisions that Tier 3 changes 

are not impacting. Eligibility will be evaluated using an average of 2012-2014 MY 

sales. For companies with no 2012 MY sales, projected sales may be used, but their 

eligibility will be re-evaluated thereafter using a three-year running average.

VNG commented that the proposed 5,000 vehicle threshold could 

potentially limit the ability (or willingness) of natural gas SVMs to scale up 

production by forcing a tradeoff between sales and regulatory burden, pointing also 

to the fact that 15,000 vehicles is only 0.1% of annual light-duty vehicle sales. We 

do not believe that the SVM relief provisions are so advantageous as to cause selflimiting of sales, except possibly in the unlikely case of a company very near the 

threshold. Even if this were to happen, moving the threshold to 15,000 would not 

prevent the same dynamic from happening at that sales level. Furthermore, our use 

of a three-year average of sales for determining SVM eligibility protects the SVMs 

from being penalized for having an especially good year not reflective of its longterm growth trend. See the MY 2017 and later light-duty GHG final rule for a 

discussion of our basis for adopting the 5,000 vehicle threshold (77 FR 62793, 

October 15, 2012).

We requested comment on extending eligibility for the Tier 3 SVM

provisions to small manufacturers that are owned by large manufacturers but are 

able to demonstrate that they are operationally independent. We established such a 

provision in the light-duty greenhouse gas (GHG) program, and CARB did so in 

LEV III. Comments from CARB and Ferrari supported this extension. No 

commenters opposed it; however, Advanced Biofuels USA recommended caution 

to avoid advantaging SVMs capable of leveraging parent company resources to 

drastically increase U.S. market share within 2-3 years. Given the establishment of 

this provision in our GHG program, and the value of this extension for 
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harmonization with LEV III, we are adopting this change into Tier 3 using the same 

eligibility criteria as in our GHG program, set forth in 40 CFR 86.1838-01(d). We 

believe these criteria are sufficiently strict and objective to address the concerns 

expressed by Advanced Biofuels USA.

To qualify as SVMs in either the light-duty or heavy-duty Tier 3 programs, 

the company’s total sales of vehicles subject to standards under Part 86 Subpart S 

count toward the vehicle sales limit, including both light- and heavy-duty vehicles. 

Companies so qualified may take advantage of SVM provisions in both sectors.

H. Compliance Provisions

1. Exhaust Emission Test Procedures

We are finalizing most of the amendments we proposed to 40 CFR part 

1066 as part of the effort to migrate test requirements from 40 CFR part 86. We 

began this process a couple of years ago when we established part 1066, but we 

applied these test procedures only to certain vehicles above 14,000 lbs gross vehicle 

weight rating (GVWR) for the purpose of measuring greenhouse gas emissions (76

FR 57470, September 15, 2011). This final rule extends these procedures, with 

some amendments, to vehicles at or below 14,000 lbs GVWR for measurement of 

both criteria pollutants and greenhouse gas emissions. The procedures in part 1066 

cover the same requirements that have been included in 40 CFR part 86, but include 

more detailed specifications for how to measure exhaust emissions using a chassis 

dynamometer. They also reference large portions of 40 CFR part 1065 to align test 

specifications that apply equally to engine-based and vehicle-based testing, such as 

CVS and analyzer specifications, calibrations, test fuels, calculations, and 

definitions of many terms. Overall, the part 1066 procedures represent a 

modernization of the part 86 procedures rather than fundamentally different 

procedures.

Until this rule, testing requirements related to chassis dynamometers have 

relied on a combination of regulatory provisions, EPA guidance documents, and 

extensive learning from industry experience that has led to a good understanding of 

best practices for operating a vehicle in the laboratory to measure emissions. The 

revisions we are finalizing capture this range of material, integrating and organizing 

these specifications and procedures to include a complete set of provisions to ensure 

that emission measurements are accurate and repeatable.

This final rule includes the following revisions to part 1066:

• Clarification of regulatory requirements.

• Migration of mass-based emission calculations from part 86 to part 1066.

• Introduction of a new NMOG calculation.
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• Revision of 40 CFR part 1066, subpart B, to increase the specificity with 

which part 1065 references are made as they pertain to testing equipment, test 

fluids, test gases, and calibration standards.

• Addition of coastdown procedures for light-duty vehicles.

• Reordering of the test sequence with respect to vehicle preparation and 

running a test.

• Specifying part 1065 procedures for PM measurement, including certain 

deviations from part 1065 for chassis testing.

• Insertion of detailed test specifications for vehicles certified under 40 CFR 

part 86, subpart S.

• Addition of provisions related to testing with four-wheel drive 

dynamometers, as described below.

• Correction of typographical errors.

We are finalizing the use of part 1065 for PM measurement with slight 

adjustments to the dilution air temperature, minimum dilution ratio, and background 

measurement requirements. By controlling the parameters that affect PM formation 

(dilution air temperature, dilution factor, sample residence time, filter face 

temperature, and filter face velocity), the procedures will reduce lab-to-lab and testto-test variability.

The regulations being finalized will provide alternative approaches to 

sample PM onto different combinations of filters. One option is to collect a sample 

for phases 1 and 2 of the FTP on a single filter, and collect a sample for phases 2 

and 3 of the FTP onto a second filter. Another option is to collect a sample for 

phases 1, 2, and 3 on a single filter. A final option is to sample PM emissions from 

two full UDDS cycles; however manufacturers choosing this option must still run a 

separate three-bag test for evaporative emission testing. We will continue to allow 

sampling under the traditional FTP methodology of a bag or filter per test phase (3 

phases in total) instead of these new methods. We are also finalizing new PM 

sampling and calculation methods as proposed.

We are revising the chassis dynamometer specifications in part 1066 by

removing the maximum roll diameter and by requiring speed and force 

measurements at a minimum frequency of 10 hertz (Hz). Some manufacturers may

be interested in testing with nonstandard dynamometer configurations, such as new 

flat-track dynamometers or old twin-roll dynamometers. We may approve the use 

of these and other nonstandard dynamometer configurations as alternative 

procedures under 40 CFR 1065.10(c)(7).
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We proposed that EPA may test vehicles with the capability of all-wheel 

drive operation with dynamometers operating in either two-wheel drive or fourwheel drive mode, regardless of the type of dynamometer that the manufacturer 

used for certifying the vehicle. However, the final regulations specify that we will 

conduct our testing using the same drive mode as the manufacturer. Vehicle 

manufacturers commented that differences in test results between a vehicle tested 

on a two-wheel drive and a four-wheel drive dynamometer might be due to 

differences in dynamometer characteristics more than in vehicle operation. Results 

of a government-industry study that tested vehicles on both two-wheel and fourwheel drive dynamometers indicated fuel economy differences in the range of ±4%, 

although the study was inconclusive with respect to the cause of the differences.421 

Based on the results of this study, we will continue to test vehicles during 

confirmatory tests using the manufacturer’s dynamometer configuration for that 

vehicle, and that test will be the official certification result. We are, however, 

finalizing revisions to 40 CFR 1066.410(g) to clarify that we may also test the 

manufacturer’s vehicle in a different dynamometer configuration than what was 

used for certification testing for information-gathering purposes. If we decide to 

perform this testing, we will depend on the manufacturer to cooperate in 

reconfiguring the test vehicle for our testing. We will continue to investigate the 

effects of four-wheel drive dynamometers on emission results and will not rule out 

possible future test procedure changes that might require certification of, or allow 

EPA to perform confirmatory testing on, any vehicle on a four-wheel drive 

dynamometer.

In their comments to this rulemaking, vehicle manufacturers stressed the 

importance to them that EPA use the same test procedures that they used for their 

certification testing when we perform confirmatory testing on their vehicles. 

Although the manufacturers did not explain the reasons for their comment, we 

presume that the manufacturers’ concern relates to situations where EPA test 

procedures would lead to higher emission levels than those resulting from a slightly

different test procedure used by a manufacturer. If so, the concern is misplaced. 

The purpose of EPA’s test procedure flexibility provisions is not to allow 

manufacturers to use test procedures as a tool to enable compliance with the 

standards – in other words, to demonstrate compliance for engines that in the 

absence of the regulatory test procedure flexibility would not meet the standard. 

Rather, the purpose is to reduce the burden of testing. We go through the 

rulemaking process to establish the specified default test procedures as a means of 

creating an objective measure of compliance with emission standards. Where we 

also include alternative procedures, they generally are not intended to change the 

conclusions from the rulemaking related to the stringency of the emission standards, 

 

421 “Four Wheel Drive Dynamometer Meeting with the Alliance of Automobile Manufacturers and 

the Global Automakers,” EPA Memo from Chris Laroo, November 13, 2013.
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or to lead to a different conclusion regarding compliance relative to the specified 

test procedures. EPA has addressed this issue previously for engine testing in 

§1065.10(a), where we note that we condition the allowance to use alternate 

procedures on the provision that they would “not affect your ability to show that 

your engines comply with the applicable emission standards.” We note further that 

this provision “generally requires emission levels to be far enough below the 

applicable emission standards so that any errors caused by greater imprecision or 

inaccuracy do not affect your ability to state unconditionally that the engines meet 

all applicable emission standards.”

In a related context, §1065.10(c)(1) explains that the intent of the test 

procedures is “to produce emission measurements equivalent to those that would 

result from measuring emissions during in-use operation”. This provision, which 

also applies for vehicle testing, envisions a process in which both the manufacturer 

and EPA can apply their engineering judgment to improve the representativeness of 

the testing. It would be appropriate for a manufacturer to ask EPA to modify our 

test procedures if the manufacturer believed EPA’s test procedures would lead to 

results that were unrepresentative of in-use operation. However, it would not be 

appropriate to ask us to modify our test procedures to make them less representative 

of in-use operation.

The proposed rule included discussion of SI units as part of emission 

measurement procedures. At this time we are not converting emission standards to 

SI units. Note however that like part 86, part 1066 relies extensively on 

calculations involving physical parameters to calculate emission rates and perform 

various calibrations and verifications. As already reflected in part 1066, 

manufacturers have used a variety of units to perform these calculations. We would 

expect that dynamometers and other laboratory equipment are all capable of 

operating in SI units even if current practice in some laboratories is to use other 

units. Moving toward standardized units for calculations will allow us to more 

carefully and appropriately specify precision values for various measured and 

calculated parameters. This will also simplify calculations, facilitate review of 

results from different laboratories, and help with communications regarding any 

round robin testing that might occur.

As proposed, we will phase in the part 1066 test procedures for certifying all 

sizes of chassis-tested vehicles. All aspects of part 1066 related to PM testing must 

be met at the start of MY 2017 for vehicles certified to the PM standards. All other 

aspects of part 1066 must be met starting with the certification of MY 2022 

vehicles. Manufacturers may begin using the part 1066 procedures before these 

deadlines, including step-wise changes to migrate gradually to part 1066 

procedures. The regulations will require that good engineering judgment be used 

during this transition to ensure that the effective stringency of the standards is not 

changed. We recognize that individual differences between part 86 and part 1066 

test procedures may have a slight upward or downward impact on measured 
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emissions, even though the combined overall impact will be negligible. Thus, 

during the migration, care must be taken to avoid applying an unbalanced mix of 

changes that could bias emissions.

As described in Section IV.D, we are finalizing new test fuel specifications 

for E10 gasoline test fuel in 40 CFR part 1065. The test fuels specified for natural 

gas and liquefied petroleum gas, while not used for very many engine families, are 

currently following different specifications under 40 CFR part 86 and part 1065. 

We intend to revisit these fuel specifications in the future in the hope of adopting 

single, comprehensive fuel specifications for natural gas and liquefied petroleum 

gas that properly represent in-use fuels for highway and nonroad applications. 

The proposal also included various technical amendments to 40 CFR part 

1065, which we are finalizing largely as proposed. See the Summary and Analysis 

of Comments for a discussion of changes we have made in response to comments. 

Of particular note is the revision to subpart F specific to preconditioning engines 

with exhaust aftertreatment devices. We are also adopting test procedures for 

unregulated pollutants such as semi-volatile compounds (PAHs, etc.). These 

technical amendments, which have no effect on the stringency of any emission 

standards, include several minor changes to clarify regulatory requirements, align 

with chassis-testing procedures where appropriate, and correct typographical errors.

2. Reduced Test Burden

We are updating the regulatory provisions that allow manufacturers to omit 

testing for certification, in-use testing, and selective enforcement audits in certain 

circumstances. Sections IV.A.3, IV.B.6, and IV.G.3 describe how this applies for 

demonstrating that vehicles meet the Tier 3 PM standards. We are also allowing 

manufacturers to omit PM measurements for fuel economy and GHG emissions 

testing that goes beyond the testing needed for certifying vehicles to the Tier 3 

standards. Requiring such measurement would add a significant burden with very

limited additional assurance that vehicles adequately control PM. We are also 

allowing manufacturers to ask us to omit PM and formaldehyde measurement for 

selective enforcement audits. If there is a concern that any type of vehicle would 

not meet the Tier 3 PM or formaldehyde standards, we will not approve a 

manufacturer’s request to omit measurement of these emissions during a selective 

enforcement audit.

The existing regulations have allowed for waived formaldehyde testing for 

gasoline- and diesel-fueled vehicles. The Tier 3 NMOG+NOX emission standards 

are stringent enough that it is unlikely that vehicles will comply with the 

NMOG+NOX standards while exceeding the formaldehyde standards. We are 

therefore continuing this waiver practice, such that manufacturers of Tier 3 vehicles 

do not need to submit formaldehyde data for certification.
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3. Miscellaneous Provisions

The following additional certification and compliance provisions are 

included in the final rule:

 The certification practice for assigned deterioration factors that are 

available for both small volume manufacturers and small volume test 

groups has matured significantly since it was first adopted. We are 

revising §86.1826 to more carefully reflect the current practice. For 

example, the existing regulations specified that manufacturers with sales 

volumes between 300 and 15,000 units per year should propose their 

own deterioration factors based on engineering analysis of emission data 

from other families. We believe it is best for EPA to develop a set of 

assigned deterioration factors that can apply to all small volume 

manufacturers and small volume test groups. The revised regulation 

accordingly spells out a process for EPA to use available information to 

establish assigned deterioration factors that can be used for any number 

of manufacturers and test groups.

 The regulations in 40 CFR part 86 rely on rounding procedures specified 

in ASTM E29. This standard is revised periodically. The newer 

versions are not likely to change in a way that affects the regulation, but 

the updates make it difficult to maintain a coordinated reference to the 

current protocol. We are addressing this by specifying that the rounding 

protocol described in 40 CFR 1065.20(e) applies, unless specified 

otherwise. We are not changing all the references in part 86; rather, we 

are defining “round” in subparts A and S to have the meaning given in 

40 CFR part 1065 so that all new regulatory text would rely on this new 

description. The rounding specifications in 40 CFR part 1065 are 

intended to be identical to those in the latest versions of ASTM E29 and 

NIST SP811. For example, this now includes procedures for 

nonstandard rounding, such as rounding to the nearest 25 units, or the 

nearest 0.05, where that is appropriate.

 Independent Commercial Importers (ICIs) are companies that import 

specialized vehicles into the U.S. and are subject to EPA requirements 

specified in 40 CFR part 85, subpart P. The standards that apply to the 

imported vehicles depend in part on the vehicle’s model year. 

Therefore, vehicles imported by ICIs in the future will eventually be 

subject to the Tier 3 standards. Because all existing ICIs are small

businesses, the Tier 3 standards generally do not apply until 2022 at the 

earliest. In addition, the certification practices for ICIs have matured 

significantly since they were first adopted. EPA is adopting two 

changes to update how the regulations affect ICIs. First, we are 

adopting a requirement for ICIs to use electric dynamometers when 
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running exhaust emission tests. Electric dynamometers have been 

required for many years for vehicle manufacturers, and EPA believes it 

is time to require that ICIs use such test equipment. In cases where an 

ICI can demonstrate that they will incur a substantial increase in 

compliance costs, the regulations include a provision allowing EPA to 

approve requests on a case-by-case basis to allow testing on other types 

of dynamometers until the ICI is able to use an electric dynamometer 

meeting current specifications. Second, we are adopting an allowance 

for ICIs to use a specific set of reduced testing procedures for up to 300 

vehicles each year that have been modified to a U.S.-certified 

configuration. This has been allowed for ICIs since 1999 and was 

approved under EPA’s authority to establish equivalent alternate test 

procedures.422 Instead of running a full set of emission tests, the 

reduced-testing requirements allow ICIs to run an FTP for exhaust 

emissions, a highway fuel economy test, and the hot soak test and the 

one-hour diurnal emission test that applied prior to the evaporative 

emission test procedures that involve 24-hour cycling of ambient 

temperatures. We do not believe these changes will have any significant 

cost impacts on ICIs. Most ICIs have electric dynamometers or can 

upgrade for a relatively small cost. The reduced testing burden 

provisions keep the cost of testing low, compared to the cost of running 

a full set of emission tests that would otherwise be required. 

 We are adopting CARB’s onboard diagnostic requirements for lightduty vehicles, light-duty trucks, and heavy-duty vehicles at or below 

14,000 lbs GVWR, as described in Section IV.C.5.d. We currently 

allow for this as an option, and almost all manufacturers do this already 

to avoid certifying multiple systems. Now that we are adopting 

evaporative provisions that are largely based on California’s regulatory

specifications and we are making efforts to adopt a single, national 

regulatory program, we believe this is an appropriate step. These 

changes apply starting in MY 2017 for vehicles subject to Tier 3 

standards. In the case of alternative fuel conversions, we continue to 

apply the requirements of 40 CFR 86.1806-05.

4. Manufacturer In-Use Verification Program (IUVP) Requirements

The fuel on which an in-use vehicle will be operated and tested is 

considered an integral part of the vehicle’s emission control system design. The 

Tier 2 program recognized that to achieve the desired emission reductions, vehicles 

must operate on the same fuel that the emission control system was originally

 

422 See 40 CFR 86.106-96(a) and Enclosure 2 to EPA Guidance letter CCD-02-04, February 6, 2002.
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designed to encounter in-use and during testing. In the Tier 2 program, we 

acknowledged that during the transition of the in-use fuel from sulfur levels of 300 

ppm to 30 ppm average level, vehicles designed for 30 ppm could encounter in-use 

sulfur levels well above the level for which their emission control systems were 

designed. To address this issue, we allowed manufacturers, with agency approval, 

to perform specific preconditioning test procedures during the IUVP testing to 

ensure that potential exposure to high sulfur fuel would not impact the emission test 

results. These procedures included specific drive cycles or maneuvers not regularly 

encountered during normal in-use operation that would result in removal of sulfur 

contamination from the emission control system. 

Consistent with the Tier 2 program, EPA continues to recognize the 

importance of the fuel to the emission control system design, particularly on Tier 3 

vehicles designed to meet the most stringent emission levels of the program (i.e., 

Bin 70 and cleaner). Under the requirements of this final rule, in-use fuel will 

transition from an average sulfur level of 30 ppm to a new average level of 10 ppm. 

These sulfur requirements are average standards. Thus, even after the transition to 

the 10 pm average sulfur level, vehicles may still encounter sulfur levels during inuse operation that are above 10 ppm, and as high as the 95 ppm cap, which could 

adversely impact the emission control system. Tier 3 vehicles tested by

manufacturers in IUVP that have been exposed to such sulfur levels could 

experience sulfur-related impacts, which in turn could cause the vehicle to 

temporarily exceed emission standards. 

To address the potential emission impact on Tier 3 vehicles from exposure 

to higher sulfur levels, we are modifying the IUVP testing process based in part on 

what was allowed under the Tier 2 program. Tier 3 vehicles tested in the IUVP are 

to be tested initially without allowing any sulfur cleanout procedure, such as a 

US06 test run prior to the FTP or Highway Fuel Economy (HFET) tests. If a 

vehicle fails the NMOG+NOX standard for the FTP or HFET cycle during the initial 

round of testing, manufacturers may perform a sulfur cleanout procedure before 

repeating the FTP or HFET, consisting of up to two US06 cycles. The measured 

US06 cycle and a preconditioning US06 cycle, if performed as part of the initial 

measured tests would serve as the cleanout procedure and therefore no additional 

US06 cycles would be allowed. Alternative sulfur cleanout procedures would 

require EPA approval. Following the sulfur cleanout procedure, the manufacturer 

will prep and soak the vehicles and then repeat the FTP and HFET tests. 

Manufacturers choosing to perform the sulfur cleanout procedure would need to 

submit evidence that the vehicle encountered high sulfur levels in the fuel just prior 

to emission testing. This would need to include an analysis of a fuel sample from 

the vehicle fuel system as received from in-use operation just prior to testing. If the 

fuel sample indicated that the vehicle had been operating on fuel containing 15 ppm 

or higher sulfur levels, only the emission results of the tests following the cleanout 

procedure would be used to determine emission compliance and whether to enter 

the in-use compliance program (IUCP). We intend to monitor the emission results 
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of in-use testing and sulfur-related test failures to determine if further reductions in 

the sulfur cap are required to ensure that Tier 3 vehicles are meeting the standards 

under in-use driving conditions.

The changes to the IUVP testing described above apply for light-duty 

vehicles, light-duty trucks, and MDPVs. These changes are not applicable to 

heavy-duty vehicles tested in the IUVP program. Also, as described in Section 

IV.D, we are incorporating leak testing into the IUVP test protocol. 

 

V. Fuel Program

Under today’s Tier 3 program, we are finalizing reductions in gasoline 

sulfur levels nationwide. These standards will help reduce current levels of sulfur 

that contribute to ambient levels of air pollution that endanger public health and 

welfare. It will also help prevent the significant impairment of the emission control 

systems expected to be used in Tier 3 technology, significantly improve the 

efficiency of emissions control systems currently in use, and continue prevention of 

the substantial adverse effects of sulfur levels on the performance of vehicle 

emissions control systems.

A. Overview

1. Background

a. History of Gasoline Sulfur Control

Sulfur is naturally occurring in crude oil. Crude oil containing higher 

concentrations of sulfur (i.e., greater than 0.5 percent) is called “sour” and crude 

containing lower sulfur concentrations (e.g., West Texas Intermediate) is referred to

as “sweet.” Regardless of the concentration, because sulfur is naturally occurring in 

crude oil, it is also naturally occurring in gasoline. As discussed in Section IV.A, 

sulfur impairs the performance of today’s vehicle emission control technologies

(i.e., precious metal catalytic converters), reducing the emission benefits of current 

and advanced vehicles. As explained below, in 2000 EPA took action to reduce 

gasoline sulfur levels under what is known as the Tier 2 Program423 and we are

taking further action with today’s Tier 3 Program.

Tier 2 was a major, comprehensive program designed to reduce emissions 

from passenger cars, light trucks, and large passenger vehicles (including sport 

utility vehicles, minivans, vans, and pick-up trucks) and the sulfur content of 

 

423 67 FR 6698 (February 10, 2000).
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gasoline. Under this program, automakers were required to manufacture lowemission vehicles when operated on low-sulfur gasoline, and refiners were required 

to produce low-sulfur gasoline nationwide. 

Required reductions in gasoline sulfur under the Tier 2 program began in 

2004 with refinery and importer caps of 300 ppm and a corporate average cap of 

120 ppm. For most refiners and importers, compliance with the final sulfur 

standards (30 annual average and 80 per-gallon cap) was required beginning in 

2006. The Tier 2 program was fully implemented on January 1, 2011 (the ultralow sulfur diesel program allowed for some extensions of the Tier 2 gasoline 

program flexibility provisions). The Tier 2 gasoline sulfur program also included

an averaging, banking, and trading (ABT) program that allowed companies to 

generate credits for implementing the required changes earlier than their required 

start date, and allowed ongoing flexibility to meet the 30 average sulfur standard.

At full implementation, the Tier 2 program (treating vehicles and fuels as a 

system) required passenger vehicles to be over 77 percent cleaner and gasoline 

sulfur to be reduced by up to 90 percent from pre-program levels.

b. Need for Additional Gasoline Sulfur Control

The authority under which we are lowering the existing gasoline sulfur 

standards comes from Clean Air Act section 211(c)(1). This is because emission 

products of gasoline with current levels of sulfur cause or contribute to air pollution 

which may reasonably be anticipated to endanger public health or welfare, and

because emission products of gasoline with current levels of sulfur will impair to a 

significant degree the emissions control device or systems on the vehicles subject to 

today’s final Tier 3 standards. For more on our legal authority to set gasoline sulfur 

standards, refer to Section V.M.

As explained in Section IV.A, robust data from many sources show that 

gasoline sulfur at current levels (i.e., around 30 ppm on average) continues to 

degrade vehicle catalytic converter performance during normal operation. NOx 

emissions are the most significantly affected by this degradation. The

NMOG+NOX vehicle emission standards, representing an 80 percent reduction 

from current Tier 2 standards, will not be possible without the gasoline sulfur 

controls we are finalizing today. Today’s 10 ppm sulfur standard should enable 

vehicle manufacturers to certify their entire product line of vehicles to the final Tier 

3 fleet average standards. Tier 3 vehicles must achieve essentially zero warmed-up 

NOX emissions to comply and must maintain this performance for up to 150,000 

miles. An increase in emissions of only a few milligrams per mile due to sulfur 

could make compliance impossible for some vehicles. The standards are projected 

to be especially challenging for larger SUVs and pick-up trucks. Based on testing 

of these vehicles, as shown in Section IV.A, reducing gasoline sulfur to 10 ppm 

should enable these vehicles to maintain their emission performance in-use over 
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their useful life. Lowering gasoline sulfur will also help reduce emissions of 

pollutants that endanger public health and welfare from vehicles already on the road 

today. As also discussed above in Section IV.A, we have tested a wide range of 

vehicles to better understand the impact that even lower gasoline sulfur could have 

on emissions. Our test data showed significant NOX and VOC reductions when 

vehicles were tested on low sulfur gasoline. As also explained in more detail in 

Section III.B, lowering average gasoline sulfur from 30 to 10 ppm will result in 

approximately 260,000 less tons of NOX and 50,000 less tons of VOC almost 

immediately as the Tier 3 gasoline sulfur standards take effect. 

2. Summary of Final Tier 3 Fuel Program Standards

The major elements of the fuel program being finalized today are 

summarized below. Please refer to sections V.B through V.J for more discussion 

on each of the elements summarized here.

a. Annual Average Sulfur Standard

Under today’s final Tier 3 fuel program, gasoline and any ethanol-gasoline 

blend will be required to have a sulfur level of 10 ppm or less on an annual average 

basis beginning January 1, 2017. The 10 ppm average will apply to a refiner or 

importer’s annual gasoline production. Similar to the Tier 2 gasoline program, the 

Tier 3 program applies to gasoline in the United States and the U.S. territories of 

Puerto Rico and the Virgin Islands, excluding California. Please see Section V.B 

for a more detailed discussion of the annual average sulfur standard.

b. Per-Gallon Sulfur Caps

Refiners and importers will continue to be subject to refinery gate per-gallon 

sulfur caps of 80 ppm. Similarly, gasoline downstream of the refinery gate (e.g., at 

terminals, retail stations, etc.) will continue to be subject to a 95 ppm per-gallon 

sulfur cap. We are also committing to continue to evaluate if reductions in the pergallon sulfur caps are warranted.

A more detailed discussion on our decision to continue the current 80 and 95 

ppm per-gallon sulfur caps, and elements of an in-use study, can be found below in 

Section V.C.

c. Small Refiner and Small Volume Refinery Provisions

As described in further detail in Section V.E.1, approved gasoline small 

refiners and small volume refineries must produce gasoline meeting the 10 ppm 

annual average sulfur standard beginning January 1, 2020. Small refiners and small 

volume refineries who meet the 10 ppm sulfur standard prior to this date may

generate credits for early Tier 3 program compliance.
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d. Averaging, Banking, and Trading (ABT) Program

Section V.D discusses our averaging, banking, and trading (ABT) program. 

Refiners and importers may to continue to generate credits for reductions in their 

gasoline sulfur levels below the current (Tier 2) 30 ppm average gasoline sulfur 

standard until December 31, 2016; and for reductions below the new 10 ppm 

average standard beginning January 1, 2017. These credits can be used for 

compliance with either the Tier 2 standard through 2016 or the Tier 3 standard 

beginning in 2017. The Tier 3 ABT program will have similar credit use provisions 

as the Tier 2 ABT program. These provisions include: five-year credit life from the 

year of generation; two-trade limit for inter-company trading; and the ability to use 

credits internally, bank for future use, or trade to other refiners/importers. 

Although credits generated prior to January 1, 2017 will be valid for five years or 

until December 31, 2019, whichever is earlier. 

e. Gasoline Additive Cap

As discussed further in Section V.C., manufacturers of gasoline additives 

that are used downstream of the refinery at less than 1.0 volume percent will be 

required to limit the sulfur contribution to the finished gasoline from the use of the

additive to less than 3 ppm when the additive is used at the maximum 

recommended treatment rate. For each batch of additive produced, the 

manufacturer must retain sulfur test records for 5 years, and must make these 

records available to EPA upon request.

Parties that introduce additives to gasoline at over 1.0 volume percent will 

be required to satisfy all of the obligations of a refiner and fuel manufacturer,

including demonstration that the finished blend meets the applicable sulfur 

specification.

f. Requirements for Denatured Fuel Ethanol and Other Gasoline 

Oxygenates

Today’s rule finalizes a 10 ppm sulfur cap for denatured fuel ethanol (DFE). 

While DFE is the predominant gasoline oxygenate currently in use, these standards 

also apply to other gasoline oxygenates. Today’s rule finalizes a 3.0 volume 

percent limit on ethanol denaturant concentration. We are adopting the current 

ASTM International specifications that only natural gasoline, gasoline blendstocks, 

or gasoline may be used as denaturants for DFE.

424

 As discussed in the Summary

and Analysis of Comments, we believe it is not necessary to finalize the proposed 

additional limits on the potential denaturants that may be used at this time. We are 

 

424 ASTM D4806-13a, “Standard Specification for Denatured Fuel Ethanol for Blending with 

Gasoline for Use as Automotive Spark-Ignition Engine Fuel”. 
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also finalizing regulatory text to state that DFE must be composed solely of carbon, 

hydrogen, oxygen, and sulfur. Testing, recordkeeping, and reporting obligations are

also being finalized to implement these new standards as discussed in Section V.G. 

Sulfur testing using approved analytical methods or volumetric blending records 

and denaturant product transfer documents (PTDs) can be used by 

manufacturers/importers of DFE in demonstrating compliance with the 10 ppm 

sulfur cap for DFE finalized today. 

g. Fuel Used in Flexible Fuel Vehicles

As discussed in Section V.H., we are deferring finalizing additional fuel 

quality requirements for E16-50 and E51-83 at this time. We continue to believe in 

the importance of implementing additional fuel quality standards for higher-level 

ethanol blends and will continue to work with stakeholders in their development 

following the publication of this final rule. 

h. Standards for Butane and Pentane

As discussed further in Section V.I, we are finalizing a 10 ppm sulfur cap 

for butane blended into gasoline effective January 1, 2017. This is consistent with 

the Tier 3 10 ppm refinery average sulfur specification finalized today. In addition, 

as discussed below in Section VI.A.4, we are also finalizing provisions to allow 

pentane to be blended into gasoline downstream of the refinery. These provisions 

are similar to the existing provisions for butane blending. This allowance will 

become effective [INSERT DATE 60 DAYS AFTER PUBLICATION IN THE 

FEDERAL REGISTER]; a 30 ppm sulfur cap will apply to pentane blended into 

gasoline (consistent with the existing sulfur cap for butane under the Tier 2 

program) until December 31, 2016, after which a 10 ppm sulfur cap will apply.

i. CNG/LPG

As discussed below in Section V.J, we are deferring establishing in-use 

sulfur requirements for compressed natural gas (CNG) and liquid propane gas 

(LPG) to provide additional time to work with stakeholders to collect data on 

current CNG/LPG sulfur content; to determine whether additional control of in-use 

CNG/LPG sulfur content is needed; and to evaluate the feasibility and costs 

associated with potential additional sulfur controls. 

B. Annual Average Sulfur Standard

Under today’s final Tier 3 fuel program, gasoline and any ethanol-gasoline 

blend will be required to have a sulfur level of 10 ppm or less on an annual average 

basis beginning January 1, 2017. The 10 ppm average will apply to a refiner or 

importer’s annual gasoline production. Similar to the Tier 2 gasoline program, the 

Tier 3 program applies to gasoline in the United States and the U.S. territories of 
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Puerto Rico and the Virgin Islands, excluding California. We are finalizing the 10 

ppm average sulfur standard both to enable the new vehicle fleet to meet the Tier 3 

vehicle standards being finalized today pursuant to CAA section 211(c)(1)(B), and 

to reduce emissions from the existing in-use vehicle fleet that endanger public 

health and welfare pursuant to section 211(c)(1)(A) of the Clean Air Act (CAA). 

We received numerous comments both in support of and against the 

proposed 10 ppm annual average sulfur standard. Commenters opposing the 

standard believe that 10 ppm is too low and/or is not needed to enable Tier 3 

vehicle technologies. Some commenters suggested that EPA should consider 

setting a less stringent sulfur standard than the proposed 10 ppm annual average 

(detailed information regarding the comments can be found in the Summary and 

Analysis of Comments document, which is located in the docket for this

rulemaking). We believe that a 10 ppm annual average standard will help reduce 

current levels of sulfur that contribute to ambient levels of air pollution that 

endanger public health and welfare. It will also help prevent the significant 

impairment of the emission control systems expected to be used in Tier 3 

technology, significantly improve the efficiency of emissions control systems 

currently in use, and continue prevention of the substantial adverse effects of sulfur 

levels on the performance of vehicle emissions control systems. This level is also 

feasible, and is the level that appropriately balances costs with the emission 

reductions that it provides and enables.

As discussed in Section IV.A.6., and further in Chapter 5 of the RIA, we 

believe that a standard of 10 ppm is appropriate, and when combined with the 

advances in emissions control technologies will be sufficient to meet the Tier 3 

emissions standards. The feasibility of the 30 mg/mi NMOG+NOx fleet average 

depends on exhaust catalyst systems that require gasoline with average sulfur levels 

of 10 ppm or less. Further, annual average sulfur levels greater than 10 ppm would 

significantly impair the emission control technology that we expect will be used to 

meet the Tier 3 standards and to ensure in-use compliance over a vehicle’s useful 

life. This is particularly a concern for some larger vehicles that will need to reduce 

NOx to near-zero levels, due to greater difficulty in reducing cold-start NMOG, in 

order to meet a combined NMOG+NOx standard. As discussed in Section IV.A.6, 

increasing gasoline sulfur from 10 ppm to 20 ppm or 30 ppm would make it 

impossible for vehicle manufacturers to meet the Tier 3 standards. Achieving Tier 

3 standards would require offsetting the resultant higher emissions but EPA is not 

aware of existing technology or developing technology that could address these 

higher emissions when taking into consideration the entire vehicle fleet. Increasing 

gasoline sulfur from 10 ppm to 20 ppm or 30 ppm would also forego the very large 

immediate reductions from the existing fleet. 

We also do not believe a sulfur standard lower than 10 ppm is necessary to 

enable vehicles to meet the Tier 3 standards. As also discussed in Section IV.A, 

reducing sulfur below 10 ppm would further reduce vehicle emissions and allow the 
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Tier 3 vehicle standards to be achieved more easily. However, we believe that a 10 

ppm average standard is sufficient to allow vehicles to meet the Tier 3 standards. 

Furthermore, as discussed below, there are significant challenges associated with 

reducing sulfur below 10 ppm. 

As explained in Section IV.A, sulfur in fuel oxidizes in the exhaust and 

coats the sites where chemical reactions can take place on the precious metal 

catalysts used in vehicles to reduce emissions of VOC, NOX, PM, CO, and toxics. 

Accordingly, any sulfur in gasoline causes vehicle emissions to increase. Sulfur 

can be burned off the catalyst during high-temperature, rich operation of the vehicle 

(i.e., aggressive driving conditions), but as long as there is any sulfur in the fuel, 

exhaust emissions will increase. Because any amount of sulfur in the fuel can have 

this effect, the lower the sulfur the better. Refiners experience the same 

phenomenon with precious metal catalysts used in the reformer and isomerization 

units at their refineries.425 To protect the precious metal catalysts in these units, 

refiners reduce the sulfur in the feed to these units to 1 ppm or below. Thus, it is 

technically possible for refiners to reduce their gasoline sulfur levels to virtually

zero. While refiners did not have reason to reduce the sulfur in FCC gasoline until 

Tier 2 required such reductions, some refiners have achieved reductions in this 

stream at some of their refineries for other reasons such as: 1) protecting the FCC 

catalyst from the contaminants in the gas oil feed, 2) reducing stack emissions from 

the regenerator of the FCC unit, and most importantly 3) increasing gasoline yields 

from the FCC unit. For most refineries, FCC gasoline accounts for about one-third 

of gasoline and before Tier 2 was the source of over 95 percent of the sulfur in 

gasoline. Under Tier 2, most refiners significantly desulfurized FCC gasoline to 

around 70 to 80 ppm, yet FCC gasoline continues to contribute the majority of 

sulfur in gasoline today.

An annual average sulfur level of 10 ppm will achieve very large immediate 

reductions from the existing fleet, as discussed in Sections III and IV. Because any

sulfur in gasoline will continue to impair vehicle catalyst performance, reducing 

sulfur levels to zero would maximize vehicle emission reductions. However, there 

are two reasons why we believe a 10 ppm average sulfur standard is sufficient and 

further reductions (e.g., 10 ppm cap or 5 ppm average) are not necessary at this 

time. First, our analysis shows that a 10 ppm annual average is sufficient to enable 

vehicles to reach the Tier 3 standards. Consequently, while reducing sulfur levels 

further would continue to yield reductions from the in-use fleet, they would not be 

necessary to enable the new Tier 3 vehicle standards to be met. Second, while 

sulfur levels would continue to reduce emissions from the existing fleet, reducing 

sulfur further below 10 ppm becomes increasingly difficult and costly. FCC 

 

425 Together, the streams from the reformer and isomerization units account for approximately onethird of gasoline. 
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naphtha is very rich in high-octane olefins. As the severity of desulfurization 

increases, more olefins are saturated, further sacrificing the octane value of this 

stream and further increasing hydrogen consumption. Making up for this lost 

octane represents a significant portion of the sulfur control costs. Furthermore, as 

desulfurization severity increases, there is an increase in the amount of sulfur 

removed (in the form of hydrogen sulfide) which recombines with the olefins in the 

FCC naphtha, thus offsetting the principal desulfurization reactions. There are 

means to deal with the recombination reactions, but they result in even greater 

capital investments. In addition, while FCC gasoline contributes the majority of 

sulfur to the finished gasoline, as the sulfur level drops below 10 ppm, the sulfur 

level of the various other gasoline streams within the refinery also become 

important. Any necessary treatment of these additional streams increases both 

capital and operating costs. 

U.S. refineries are currently in different positions, both technically and 

financially. In general, they are configured to handle the different crude oils they 

process and turn them into a widely varying product slate to match available 

markets. Those processing heavier, sour crudes may have a more challenging time 

reducing gasoline sulfur under the Tier 3 program. Also, those with higher sulfur 

levels in other refinery streams may have a more difficult time desulfurizing 

gasoline. Perhaps most important, U.S. refineries vary greatly in size (atmospheric 

crude capacities range from less than 5,000 to more than 500,000 barrels per day) 

and thus have different economies of scale for adding capital to their refineries. 

Therefore, it can be less costly per gallon for some larger refineries to get down to 

10 ppm than for smaller refineries, as discussed in Chapter 5 of the RIA. As a 

result, with a 10 ppm average standard, the flexibility afforded by the ABT program 

helps those refineries with very high costs. They have the option of staying above 

10 ppm if they can acquire credits from other refineries that were able to lower their 

sulfur level below 10 ppm. However, if the gasoline sulfur standard were lower, 

this would essentially end the ability of refiners to average sulfur reductions across 

their refineries. There simply would not be enough opportunity to generate credits 

at levels much below 10 ppm. 

As discussed further in Chapter 5 of the RIA, we assessed the potential costs 

of an annual average standard lower than 10 ppm (e.g., 5 ppm). Our analysis shows 

that sulfur control costs for refineries to meet a standard below 10 ppm could be on 

the order of two times more costly per ppm-gallon of gasoline sulfur reduced. In 

addition, a standard below 10 ppm could be cost-prohibitive for more challenged 

refineries. Further, such a standard would also introduce additional costs to address 

the contribution to gasoline sulfur from gasoline additives, transmix, ethanol 

denaturants, and contamination in the distribution system. 

Therefore, we believe that the 10 ppm annual average standard will help 

reduce current levels of sulfur that contribute to ambient levels of air pollution that 

endanger public health and welfare. It will also help prevent significant impairment 
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of the emission control systems expected to be used in Tier 3 technology, 

significantly improve the efficiency of emissions control systems currently in use, 

and continue prevention of the substantial adverse effects of sulfur on the 

performance of vehicle emissions control systems. The level is also feasible 

(especially considering its associated ABT provisions, described in Section V.D), 

and is the point which appropriately balances costs with the emission reductions 

that it provides and enables.

 

C. Per-Gallon Sulfur Caps

1. Standards

The final Tier 3 program is composed of a 10 ppm refinery annual average 

sulfur standard (discussed above in Section V.B) with an 80 ppm per-gallon cap at 

the refinery gate and a 95 ppm per-gallon cap downstream; these per-gallon caps 

currently exist under the Tier 2 program. We believe this is the most prudent 

approach for lowering in-use sulfur while maintaining flexibility considering cost 

and other factors. These per-gallon caps are important in the context of an average 

sulfur standard to provide an upper limit on the sulfur concentration that vehicles 

must be designed to tolerate. The caps also limit downstream sulfur contamination 

and enable the enforcement of the gasoline sulfur standard in-use. Our 10 ppm 

average standard with higher per-gallon caps compares to a 10 ppm cap standard in 

much of Europe, Japan, and Korea. In addition to the gasoline standards we are 

finalizing today, we are also finalizing caps on the sulfur content of gasoline 

additives, to limit their contribution to the overall in-use gasoline sulfur level. 

a. What We Proposed

We proposed two options for the per-gallon sulfur caps—maintaining the 

Tier 2 80 ppm refinery gate sulfur and 95 ppm downstream sulfur caps and, 

beginning January 1, 2020, lowering to 50 ppm refinery gate and 65 ppm

downstream caps. The 50 ppm refinery gate cap was proposed to take effect on 

January 1, 2020, as this is the date when the small refiner, small volume refinery, 

and early credit use provisions would expire; and also to avoid forcing additional 

refinery investments during the early credit usage period. We also requested 

comment on lowering the caps to 20 ppm at the refinery gate and 25 ppm 

downstream.

We received comments on both of the proposed per-gallon cap options of 

80/95 ppm and 50/65 ppm, as well as comments on finalizing lower caps of 20/25 

ppm and a 20 ppm overall cap. Comments supporting lower caps noted potential 

environmental benefits, greater certainty that vehicles would see lower and more 

uniform gasoline sulfur levels, and enabling new vehicle technologies that require 
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very low sulfur levels. Comments in support of maintaining the current Tier 2 caps 

cited concerns on cost, flexibility for turnarounds/unplanned shut downs (due to 

refinery fire, natural disaster, etc.), and potential impacts on gasoline supply and 

pricing. Detailed information regarding the comments we received on the pergallon sulfur caps is provided in the Summary and Analysis of Comments 

document, which is available in the rulemaking record.

b. Final Refinery Gate Sulfur Cap

In today’s action, we are retaining the 80 ppm refinery gate cap. The 

refinery gate cap provides flexibility for batch-to-batch variability that naturally 

occurs at a refinery due to the varying types of crude that refineries process, 

variations in unit operations, and variations in product mix. It further provides for 

flexibility during unit turnarounds, and unplanned upsets (e.g., refinery fires, natural 

disasters, etc.), to avoid a complete refinery shutdown. A lower cap could create 

situations where refiners would need to store more off-spec gasoline for future 

processing. However, if a refinery does not have adequate tankage for storing this 

product, and/or if its processing units are not large enough to “catch up” in refining 

off-spec product, it could result in significant impacts to fuel pricing or supply. For 

a refiner that produces multiple products, any potential supply impacts could also 

impact other fuel markets (e.g., diesel, jet fuel, etc.). Additionally, the refinery gate 

cap is a “hard” limit—a refinery’s actual production has to be well below this limit 

to account for in-use testing tolerances, safety margins, and any additives that a 

refiner may need to add prior to the fuel leaving the refinery. An 80 ppm refinery

gate cap will provide refiners needed flexibility, and more certainty that they will be 

able to continue producing and distributing at least some gasoline during 

turnarounds/upsets to avoid a total shutdown. It will further provide more certainty

for transmix processors, additive manufacturers and other downstream parties.

As described below in Section VII, we believe that most refineries would 

not have significant costs as a result of the Tier 3 program because they will be able 

to meet the 10 ppm average sulfur standard largely through revamps and 

operational changes at their facilities, rather than installing grassroots units. 

Lowering to a cap of 50 ppm would directionally increase the costs of the Tier 3 

program. The American Petroleum Institute (API) provided a detailed study with 

their comments426 quantifying the additional costs associated with successively

more stringent per-gallon caps. While we do not agree with the study’s overall cost 

analysis, we do agree that with a refinery gate cap of 50 ppm, a number of refiners 

would incur higher capital costs due to the decreased ability to handle off-spec 

 

426 “Economic and Supply Impacts of a Reduced Cap on Gasoline Sulfur Content; Prepared for the

American Petroleum Institute”; Turner, Mason & Company. Document number: EPA-HQ-OAR2011-0135-4285; API-AFPM Attachment 13.
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product with a lower refinery gate cap. As refiners must ensure that they can 

continue to produce saleable product and meet demand in the event of an upset or 

an off-spec batch of fuel, the need for installation of additional tankage and/or 

increased refinery processing capability would be greater with a 50 ppm refinery

gate cap. While at the time of the proposal we believed that a cap of 50 ppm would 

have little cost impact, our more recent analysis shows that a 50 ppm cap would 

increase the cost of the Tier 3 gasoline sulfur standards by approximately 10 percent 

(see RIA Chapter 5.2.2.4). At the same time, the more stringent cap with its 

associated increase in cost would be unlikely to provide significant additional 

emission benefits nationwide. As discussed previously in Sections III and IV 

above, the emissions benefits associated with the Tier 3 program are mainly driven 

by the reduction in the average sulfur content of gasoline from 30 to 10 ppm, since 

vehicle emissions are proportional to the sulfur content of the fuel. Changes in the 

cap would not affect this. In the context of the final ABT provisions, a higher cap 

does allow for increases in emissions on a temporal basis as one batch of fuel is 

allowed to have higher sulfur levels. However, this is then offset by reductions in 

emissions from batches of fuel that are then required to be below the 10 ppm 

average standard. Similarly, the final ABT provisions allow for the possibility that 

the fuel from different refineries will cause varying emission reductions as one 

refinery’s higher average sulfur levels would lead to less emission reductions inuse. However, this is then offset by greater reductions in emissions due to the fuel 

produced by refineries with sulfur levels below the average standard.

Based on our cost analysis, which is discussed below in Section VII.B., we 

project nearly 40% of the gasoline pool would be at 5 ppm, about 45% at 10 ppm 

and the remaining approximately 15% at levels higher than 10 ppm. The sulfur 

level for this 15% in our analysis ranges from 11 ppm all the way up to 70 ppm. 

However, as discussed in Section VII.B., these high sulfur levels are more a 

function of the limitations of our analysis where we could only model these 

refineries as remaining at their current Tier 2 sulfur levels. We anticipate that in 

most (if not all) cases refineries will make operational changes and/or investments 

in order to reduce their credit burden and reduce their compliance costs. This 

anticipation, along with the fact that a 10 ppm average standard by definition limits 

the amount of gasoline that can remain at higher sulfur levels (regardless of the 

cap), means that we anticipate most refineries, including those using credits, will

still average less than 20 or 30 ppm in their physical gasoline production. 

Nevertheless, the final ABT program does allow for the possibility (regardless of 

the cap) that were this higher sulfur fuel to be concentrated in any certain 

geographical area, it would not receive the full emission reductions from the Tier 3 

program. We have considered the potential for areas to consistently receive fuel 

that might be predominantly higher than the 10 ppm average. Because refineries 

generating credits and using credits are interspersed across the country, and because 

most areas receive a considerable portion of their fuel by pipeline, barge, rail, or 

truck from refineries in other areas, we expect the variation in average sulfur levels 
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across the country to be too limited to warrant lowering the per-gallon cap to 50 

ppm. Given the stringency of the 10 ppm average standard, we predict that in-use 

sulfur levels will generally be well below 50 ppm. 

Further reductions in the refinery gate cap are also not needed to enable the 

vehicle emissions standards, as the vehicle standards are a function of the 10 ppm 

annual average sulfur standard. While vehicle manufacturers have expressed 

concerns about the potential impacts on emissions performance if individual 

vehicles are exposed to gasoline above 10 ppm due to higher per-gallon caps and/or 

credit usage427, we believe that vehicles will see sulfur levels closer to the 10 ppm 

average rather than the 80 ppm cap due to the fact that the 10 ppm average will 

drive reductions in gasoline sulfur levels.

Thus, we believe it is prudent at this time to retain an 80 ppm refinery gate 

cap. However, we are committing to monitor and further evaluate in-use sulfur 

levels and their impact on vehicle emissions. If it is warranted, we will reassess the 

sulfur cap level and the need for potential future regulatory action. Such ongoing 

evaluation will include analyses of: in-use fuel surveys; batch data that refineries 

are required to submit; and the sulfur credit market. It will also include the 

evaluation of any issues or concerns that might arise during implementation of the 

program. Finally, we will also carry out an ongoing evaluation of data submitted by

the vehicle manufacturers on the performance of their Tier 3 vehicles in-use. 

c. Downstream Sulfur Cap

With regard to the downstream sulfur cap, we believe that maintaining a 15

ppm differential between the refinery gate sulfur cap and the downstream sulfur cap 

will provide pipeline operators, transmix processors, and gasoline additive users the 

same flexibility as was provided under the Tier 2 program. As was the case under 

the Tier 2 program, allowing a 15 ppm differential is needed to ensure adequate

flexibility in accommodating gasoline produced from transmix, instances of 

contamination during distribution, and for the use of necessary (sulfur-containing) 

additives. In rare circumstances when the sulfur contribution from all these sources 

are coincidently at their maximum levels, a very limited number of batches of 

gasoline at the 95 ppm downstream sulfur cap may be present in the distribution 

system. However, we expect that this will not have a substantial impact on the 

average sulfur content of in-use gasoline. Comments received on this issue were 

generally in support of maintaining the 15 ppm delta.

Pipeline operators are currently allowed to blend limited volumes of 

transmix into gasoline in their systems provided that the resulting gasoline meets all 

 

427 Alliance of Automobile Manufacturers (2011, October 6). Letter to EPA Administrator, Lisa 

Jackson.
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fuel quality specifications and the endpoint of the blended gasoline does not exceed 

437 °F.428 This enables pipeline operators to avoid the installation of additional 

transmix storage and loading equipment at a number of remote locations to 

facilitate shipping small volumes of transmix to processing facilities by truck. 

Currently transmix processors must produce gasoline sufficiently below the 

95 ppm downstream sulfur cap to accommodate any downstream sulfur increases 

from the use of gasoline additives and contamination from further distribution. 

The sulfur content of the gasoline produced by transmix processors is determined 

by the sulfur content of the transmix they receive, which in turn is primarily a 

function of the sulfur content of gasoline and jet fuel components in the transmix.429 

Transmix processors do not handle sufficient volumes to support the installation of 

currently available desulfurization units.430 

d. Accounting for Ethanol Blending in the Determination of Compliance 

with Gasoline Sulfur Requirements

In demonstrating compliance with the gasoline sulfur standards finalized 

today, gasoline refiners and importers may adjust the sulfur levels in the gasoline 

and blendstocks for oxygenate blending (BOBs) that they produce/import to 

account for the downstream addition of ethanol. We proposed that the sulfur 

content of denatured fuel ethanol (DFE) used for downstream blending would be 

assumed to be 10 ppm in making such demonstrations of compliance. Refiners 

commented that refiners and importers should be allowed to either use the actual 

sulfur value of the DFE or conduct laboratory hand blends of a representative 

sample of DFE to determine the effect on the sulfur content of the blended fuel 

from the addition of DFE. We agree that refiners and importers should be allowed 

to use the actual sulfur content of DFE when a sulfur test result is available and 

when the refiner can demonstrate that the test result was derived from a 

representative sample of the DFE that was blended with the gasoline or BOB. The 

sulfur content of in-use DFE will typically be lower than the 10 ppm sulfur cap 

finalized today for DFE. We assumed that DFE would have an average sulfur 

content of 5 ppm in conducting the refinery analysis to support this rule. Therefore, 

today’s final rule requires that in determining their compliance with today’s sulfur 

 

428 The requirements for transmix blenders are contained in 40 CFR 80.84(d). 437 °F is the 

maximum endpoint allowed for gasoline in ASTM D4814. 

429 Transmix is a by-product of the multi-product pipeline distribution system. 40 CFR 80.84(a) 

defines transmix pipeline interface that does not meet the specifications for a fuel that can be used or 

sold, and that is composed solely of any combination of: previously certified gasoline (including 

previously certified gasoline blendstocks that become gasoline solely upon the addition of an 

oxygenate); distillate fuel; or gasoline blendstocks that are suitable for use as a blendstock without 

further processing.

430 Transmix processors produce ~0.1 percent of the gasoline consumed in the U.S.
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standards, refiners and importers must either use the actual sulfur content of the 

DFE established through testing of the DFE actually blended or assume a 5 ppm 

sulfur content for the DFE added downstream. To prevent potential bias, a refiner 

or importer must choose to use only one method during each annual compliance 

period. 

2. Requirements for Gasoline Additives

Today’s action finalizes the requirement that manufacturers of gasoline 

additives used downstream of the refinery at less than 1 volume percent must limit 

the sulfur contribution to the finished gasoline from the use of their additive to no 

more than 3 ppm when the additive is used at the maximum recommended 

treatment rate. The additive manufacturer will be required to maintain records of its 

additive production quality control activities which demonstrate that the sulfur 

content of additive production batches is such that when the additive is used at its 

maximum recommended treatment rate it will add no more than 3 ppm to sulfur 

content of the finished gasoline. We received comments in support of our proposed 

requirements (these comments can be found in the docket to this rulemaking, and 

are summarized in the Summary and Analysis of Comments document, which is 

also located in the docket). An environmental organization commented that the 

sulfur contribution from additives can have a material effect on emissions 

performance given the level of vehicle emissions control that is being finalized 

today. We also received comments from gasoline additive manufactures were in 

favor of the proposed controls. 

The requirements finalized today are designed to prevent the potential 

dumping of high sulfur materials into gasoline under the guise of the addition of 

gasoline additives. We continue to believe that all current gasoline additives 

contribute less than 3 ppm to the sulfur content of the finished fuel when used at the 

maximum recommended treatment rate (with 3 ppm being the extreme). Normal 

additive production quality control practices already have had to consider the sulfur 

contribution of the additive to finished gasoline as a result of the Tier 2 gasoline 

sulfur requirements. The maximum recommended treatment rate is already stated 

on product transfer document or packaging for the additive. Additive 

manufacturers are to retain production quality control records for 5 years and make 

these available to EPA upon request. Therefore, the requirements finalized today

will not constrain the use of genuine gasoline additives or result in significant 

additional costs to gasoline additive manufacturers. Parties that introduce additives 

to gasoline at over 1.0 volume percent are required to satisfy all of the obligations 

of a refiner and fuel manufacturer including demonstration that the finished blend 

meets the applicable sulfur specification.

We also received comments from an environmental organization requesting 

that EPA promulgate limits on the combined sulfur contribution for all additives 

blended into a batch of gasoline in addition to controlling the sulfur contribution 
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from individual additives. We believe that such additional controls are not 

necessary, would add an unwarranted additional compliance burden, and could 

interfere with the use of necessary downstream additives. Certain additives that

provide critical fuel performance characteristics (e.g., corrosion control, 

demulsifiers) contain sulfur-containing compounds as an essential functional 

component. Such additives are used to remedy specific instances of gasoline 

quality problems, and their treatment rate is governed by the desire to limit the 

added cost from their use.

D. Averaging, Banking, and Trading Program 

In today’s rule, we are finalizing an ABT program that will reduce the 

compliance costs and promote the feasibility of the Tier 3 gasoline sulfur program, 

because it will allow refiners and importers to choose the most economical 

compliance strategy (i.e., investment in technology, credits, or both) to meet the 10 

ppm average sulfur standard. In response to comments received on our proposal, 

we have simplified and added flexibility to the ABT program. The ABT program 

allows refiners and importers to continue to generate credits for overcompliance 

with the current Tier 2 30 ppm average gasoline sulfur standard through 2016, and 

the new 10 ppm average standard beginning in 2017. (Small refiners and small 

volume refineries have a January 1, 2020 compliance date, as described below.) 

These credits can be used for compliance with either the Tier 2 standard through 

2016 or the Tier 3 standard beginning in 2017. Credits can also be banked for 

future use or transferred to other refineries for compliance with the average sulfur 

standard. In addition, we are allowing refiners and importers to also use any valid 

credits banked from 2012 and 2013 under the Tier 2 program toward compliance 

with either the Tier 2 or Tier 3 sulfur programs. We believe these provisions will 

provide a seamless transition from Tier 2 to the Tier 3 program.

1. How Will the ABT Program Assist with Compliance?

The Tier 3 ABT program allows refiners and importers the flexibility to: 1) 

have varying gasoline sulfur levels for their batches of fuel as long as they meet the 

10 ppm average over the course of the year; 2) use credits generated at one of its 

refineries to offset higher sulfur gasoline produced at another of its refineries; 3) 

bank generated credits for future use; and 4) participate in trading (via buying 

and/or selling) of credits from another refiner to help lower costs. The ABT

program allows for the generation of credits by refiners and importers for overcompliance with the 10 ppm sulfur standard (on a refinery/facility basis), and for 

the transfer of these credits to other refiners (for use a refinery) to reduce or 

eliminate their need to make capital investments to meet the 10 ppm standard. The 

ABT program will provide refiners and importers with multiple approaches to 

compliance, and each can choose the approach that best minimizes their costs.
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2. ABT Modeling

For the proposed rule, we modeled the effects of an ABT program on 

refinery compliance. Our modeling determined the lowest cost approach on a 

refinery-by-refinery basis under two scenarios: the first, in which every refinery has 

the opportunity to make credit transfers with every other refinery in the nation, and 

a more limited scenario in which credit transfers would only occur within 

companies that own more than one refinery.

In developing today’s final program, we also analyzed the Tier 2 credit 

market and found that, currently, Tier 2 sulfur credits are both transferred within 

companies (intra-company) and traded between companies (inter-company). As 

discussed in Chapter 4.3 of the RIA, in 2012 approximately 56% of the Tier 2 credit 

transactions were inter-company trades. The remaining 44% were intra-company

trades. This analysis shows that there is a functioning, well-established gasoline 

sulfur credit trading market. There does not appear to be any hindrance to credit 

trading currently or in the future. We anticipate that a significant number of 

refineries will take advantage of the opportunity to generate or use credits, thus 

lowering their compliance burden for the Tier 3 program. For a more complete 

discussion of our analysis of credit trading and the associated cost impacts of the

ABT program, refer to Chapter 4.3 of the RIA. 

3. Eligibility

Consistent with our proposal, under today’s final program, sulfur credits 

may be generated by both U.S. refiners and importers of gasoline into the U.S. only

for gasoline that is subject to the sulfur requirements as described in the regulations 

at §80.1603. This excludes gasoline produced or imported for use in California

(“California gasoline”) and gasoline designated for export, but includes gasoline 

produced by California refineries for use outside the state. We sought comment in 

the proposed rule on whether or not to include California. All comments received 

on this issue were against the inclusion of such gasoline in the ABT program, 

largely because it would cause additional burden but provide no appreciable credits 

to the market to justify the additional compliance burden (such as batch reporting). 

We agree with these comments, and are finalizing the provision that California 

gasoline and gasoline for export will not be included in the ABT program. In order 

to exclude exported gasoline and California gasoline, refiners must keep records to 

demonstrate that the excluded gasoline was designated for export or as California 

gasoline, and was actually exported or used in California.

While under existing fuel programs (e.g., MSAT2), we precluded importers 

from generating “early” credits (credits generated before a program start date), we 

are allowing importers to generate early credits in the Tier 3 ABT program, 

consistent with our proposal. Importers were previously precluded from generating 

early credits because they generally did not need additional lead time to comply
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with our fuel standards (as they most likely would not be investing in new refining 

technologies) and we also thought it would be difficult for them to establish 

representative baselines from which early credits could be generated. However, 

early credit baselines are not a part of the Tier 3 program, as discussed above. In 

addition, commenters noted that while importers may not necessarily have to take 

actions to desulfurize fuel like domestic refiners do, these parties may have to pay

premiums on obtaining lower sulfur fuel, thus their efforts to provide lower sulfur 

fuel should also be able to generate early credits. Thus, we are finalizing provisions 

allowing importers to generate early credits for sending over-compliant gasoline to 

the United States prior to January 1, 2017. 

We proposed to limit credit generation to refiners and importers. Under the 

Tier 2 gasoline program, we allow refiners who produce gasoline by combining 

blendstocks together or adding blendstocks to previously certified gasoline (refinerblenders) to participate in the in the sulfur ABT program, but do not allow butane 

blenders who comply with the reduced sampling, testing, and reporting 

requirements to participate in the sulfur ABT program. 431 We are extending these 

provisions to butane and pentane blenders under the Tier 3 program.432 Under 

today’s rule, any refiner who uses the reduced sampling, testing, and reporting 

provisions for blending butane or pentane into gasoline will not be allowed to 

generate credits. Refiner-blenders who comply with the full suite of sampling, 

testing, and reporting requirements will, however, be allowed to generate credits.

We received several comments from ethanol producers and Growth Energy

(representing ethanol producers), who commented that DFE should be subject to an 

annual average sulfur standard and that ethanol producers should be able to 

participate in the ABT program that is available to refiners and importers of 

gasoline. These commenters stated that preventing them from participating in the 

ABT program would provide refiners with pathways to allow delayed adoption of 

cleaner fuel standards at their expense. Some ethanol producers commented that 

they should be allowed to participate in the ABT program as a means of offsetting 

the additional cost of the proposed per-batch sulfur testing and reporting 

requirements. We also received comments from refiners stating that credit 

generation should be permitted only for refiners and importers. 

As in existing EPA fuel programs, we continue to believe that it is not 

appropriate expand the ABT provisions to cover ethanol producers and oxygenate 

blenders for several reasons. First, expanding the ABT program beyond refiners

and importers could greatly increase the number of parties participating thereby 

potentially complicating EPA compliance assurance activities while having little 

 

431 The provisions for butane blenders are located in 40 CFR 80.82.

432 See Section V.I. for a discussion of the requirements for pentane blenders.
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overall impact on the sulfur credit pool. Second, the current ABT program under 

the Tier 2 gasoline sulfur program, which is limited to gasoline refiners and 

importers, has functioned effectively with few compliance irregularities. Third, 

experience with the unleaded gasoline program suggests widespread abuse and 

fraud when credits have been allowed to be generated or sold by parties other than 

refiners or importers subject to the regulations. Fourth, it would require a 

considerably more complicated compliance structure, including the application of 

all refiner responsibilities to ethanol producers and blenders. Fifth, there is no need 

for DFE producers to generate credits in order to recoup the value for any lower 

sulfur content of their product. The value of any lower sulfur content will be 

reflected in the market price of DFE, similar to the octane value to refiners. Sixth, 

the sulfur ABT provisions were included to ease the burden of compliance for 

refiners who have to make capital changes to their facilities to meet today’s more 

stringent sulfur standards. In addition to reducing the cost of today’s gasoline 

sulfur program, the ABT provisions allow for an earlier effective date of the sulfur 

standards than would otherwise be possible. Such considerations are not applicable 

to ethanol producers since capital expenditures for desulfurization equipment or 

other equipment will not be needed at their facilities to comply with the sulfur 

standards finalized today.433 Finally, overcompliance with the per-gallon sulfur 

cap for DFE is not a valid basis for credit generation. We expect that in all cases,

the DFE sulfur level will be below the cap. To allow credit generation for these 

parties, we would need to set an additional annual average sulfur standard for DFE 

at some level below 10 ppm and allow credits to be generated for overcompliance 

with that standard. Accordingly, we do not believe it is appropriate to allow ethanol 

producers or blenders to generate sulfur credits under the Tier 3 gasoline sulfur 

program, and as such, we are not finalizing such a provision. The Tier 3 rule 

prohibits any person downstream of the refinery or importer that produced or 

imported gasoline, CBOB, or RBOB who adds oxygenate to such product from 

including the volume and sulfur content of the oxygenate in any compliance 

calculations for credit generation.

4. Credit Generation and Use

Under the Tier 3 ABT program, the credit generation provisions are nearly

the same as those under the Tier 2 program. In essence, the Tier 2 program simply

continues with a lower standard below which credits are generated. Refiners and 

importers are allowed to average within and across companies to meet the standard 

in the most cost-effective manner possible, including generating and using credits. 

For Tier 3, refiners and importers can generate credits for overcomplying with the 

10 ppm standard on a volume-weighted annual average basis beginning January 1, 

2017. Credit generation periods remain 12 months long and continue to be 

 

433 The requirements for ethanol producers finalized today are discussed in Section V.G.4.
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synchronized with annual compliance demonstration periods. The final Tier 3 ABT 

program provisions for approved small refiners and small volume refineries are 

discussed below in Section V.D.6.

Consistent with our proposal, and to encourage early gasoline 

desulfurization and give the refining industry flexibility to stagger their investments 

over time, we are also finalizing provisions to allow refiners and importers to 

generate credits prior to January 1, 2017 (i.e., early credits).

We proposed an early credit program for overcompliance with the current 

Tier 2 30 ppm gasoline sulfur standard from January 1, 2014 through December 31, 

2016. These early credits were proposed to have a credit life of three years, and 

could be used through December 31, 2019. We also proposed that refiners and 

importers who generated early credits would then have to designate them at the end 

of the compliance year as either Tier 2 credits or Tier 3 early credits, and the credits 

would have to be used in accordance with the designation.

We received several comments on our early credit provisions. Some 

commenters stated that the requirement to designate credits as either Tier 2 or Tier 

3 would not provide refiners and importers the intended amount of flexibility, as 

they may not necessarily be able to predict if they will need to use those early

credits for either Tier 2 or Tier 3 compliance. Further, commenters were concerned 

that if more refiners than anticipated opt to bank the credits for possible future use 

at their own refineries, it could result in less credits being made available to the 

market. We also received comments both in support of and against the proposed 

three-year credit life. Some commenters stated that they believed that all credits 

should have a five-year life to provide maximum flexibility and more certainty on 

the availability of credits; while other commenters supported the three-year credit 

life limit, because it would coincide with the end of the small refiner/small refinery 

provisions thus providing more certainty of the benefits of the Tier 3 program. 

Finally, while not proposed, we received many comments requesting that EPA 

clarify what would become of “banked” Tier 2 credits (Tier 2 credits generated in 

2012 and/or 2013 that were not used before the end of their five-year credit life and 

would have expired when the Tier 3 program began, under the terms of the 

proposed ABT program). Commenters further stated that these credits should not 

expire, but rather should be allowed to receive their full five-year credit life, as they

represent actual reductions in refinery sulfur levels.

As discussed above, we are finalizing a more flexible approach to the ABT 

program than what we proposed. We believe this will provide for a more seamless 

transition from the Tier 2 to the Tier 3 credit programs and more certainty on credit 

availability.

Consistent with our proposal, refiners and importers may begin generating 

early credits on January 1, 2014, and continue through December 31, 2016. These 
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credits will be generated on an annual average basis, from a demonstration that the 

refiner or importer’s annual average gasoline sulfur level is below the current Tier 2 

30 ppm annual average sulfur standard. We believe this simple early credit 

approach is possible because U.S. gasoline was averaging around 30 ppm as we 

started developing the Tier 3 program, based on compliance data. Since refiners 

and importers would need to continue to comply with the existing Tier 2 sulfur 

standards during the early credit period, absent Tier 3, they would need to maintain 

this level of performance on an industry average basis. Accordingly, any additional 

gasoline sulfur reductions beyond 30 ppm will be attributed to the proposed Tier 3 

program. 

In response to comments received, we are not requiring that credits be 

designated as either Tier 2 or Tier 3 and only used for the program for which they 

were designated. Refiners and importers may use early credits either for ongoing 

compliance with the Tier 2 program, or bank them for future compliance with the 

Tier 3 program (within the limits of the credit life restrictions). Essentially, the Tier 

2 credit generation provisions simply continue, and any banked credits generated in 

2014 through 2016 that were not used for compliance with the Tier 2 standards 

would be carried over for use in complying with Tier 3. We believe that this will 

allow for more certainty of credit availability before refiners must make their Tier 3 

investment decisions, thus reducing the cost of the program. It will also avoid any

incentive for refiners to use up banked Tier 2 credits prior to 2017 causing 

increased in-use sulfur levels and emissions.

Based on our analysis of the Tier 2 credit market for 2012, we believe that 

there will be a balance of 2012 banked credits equivalent to approximately two 

months of compliance, and we anticipate a similar amount (perhaps more) for 2013. 

Although we did not propose to allow for banked 2012 and 2013 Tier 2 credits to be 

used for compliance with the Tier 3 program, we are finalizing this provision for a 

number of reasons. First, the Tier 2 banked credits represent real reductions—

refiners and importers are currently generating these credits for overcompliance 

with the Tier 2 gasoline sulfur standard. Second, allowing these banked credits to 

receive their full five-year credit life will provide more assurance of the credit 

availability for trading for those who need them to comply with Tier 3 without a 

large capital investment. As previously explained, this will allow for more certainty 

of credits available far before making Tier 3 investment decisions, thus reducing the 

cost of the program. A lack of certainty in the credit trading market could lead to 

refiners banking more credits than usual for their own use rather than allowing these 

credits to be available in the market for trading. As shown in Chapter 4.3 of the 

RIA, refiners tend to hold credits as an insurance policy until they approach the end 

of their credit life. If credit-generating refiners continue with this approach, credits 

generated in 2012 and 2013 will likely be available for purchase in 2017 and 2018 

for those refiners that may want to rely on them for compliance (along with 

additional early credits generated in 2014 through 2016). Finally, as we anticipate 

that these credits will be equal to about four months of compliance, the allowance 
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of 2012 and 2013 banked Tier 2 credits makes for a more flexible program by

effectively allowing for a small amount of additional lead time without adversely 

affecting the overall benefits of the Tier 3 program. As discussed previously, this 

will avoid any incentive for refiners to use up banked Tier 2 credits prior to 2017 

causing increased in-use sulfur levels and emissions. We believe these provisions 

will allow the Tier 3 program to begin on January 1, 2017, with more certainty

regarding the availability of credits for those refiners needing (or choosing) to defer 

investment to better align with their existing turnaround/shutdown schedules.

All credits generated before January 1, 2017 will be valid for five years or 

until December 31, 2019, whichever is earlier—no early credits may be used for 

compliance beginning January 1, 2020. Thus, banked Tier 2 credits generated in 

2012 and 2013 will receive their full five-year life and will not expire at the start of 

the Tier 3 program. However, credits generated in 2015 and 2016 that are unused 

as of December 31, 2019 will expire and become invalid. We believe that 

structuring the early credit program this way will offer considerable flexibility to 

refiners phasing in Tier 3 gasoline sulfur controls, while still placing a date at which 

point the intended sulfur program will be fully implemented and enforceable—

January 1, 2020 (the same date small refiners and small refineries must begin 

complying with the 10 ppm sulfur standard). This will also provide a date certain to 

give auto manufacturers greater confidence for the design of their vehicles that all 

vehicles in-use are running on 10 ppm average fuel. Otherwise, it is possible that 

the greater ease of generating early credits relative to 30 ppm sulfur (as opposed to 

10 ppm in 2017 and beyond) would allow higher sulfur levels to continue well 

beyond 2019.

Consistent with our proposal, all credits generated beginning January 1, 

2017 will be for overcompliance with the Tier 3 10 ppm annual average sulfur 

standard, and will have a five-year credit life. We believe five years will give 

refiners and importers sufficient time to use credits generated in previous years 

while still placing limitations on credit life to help with enforcement. Five years is 

consistent with the Tier 2 ABT program, as well as the current credit life and 

recordkeeping provisions for other 40 CFR part 80 fuels programs, and coincides 

with the applicable statute of limitations for violations by parties who generate 

invalid credits. Credits must be used within five years from the year they were 

generated (regardless of when/if they are traded), otherwise they will expire and 

become invalid. For example, credits generated in 2017 can be applied towards 

2018-2022 compliance, as well as 2017 compliance. After March 31, 2023 (when 

reports for the 2022 annual compliance period will be due), credits generated in 

2017 will expire and become invalid. Similarly, credits generated in 2018 can be 

applied towards 2019-2023 compliance, as well as 2018 compliance. After March 

31, 2024, credits generated in 2018 expire, and so on and so forth.
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5. Credit Trading Provisions

We are also finalizing provisions for credit trading in Tier 3 that are 

identical to those under the current Tier 2 program. As in that program, it is 

possible that sulfur credits could be generated by one party, subsequently 

transferred or used in good faith by another, and later found to have been calculated 

or created improperly or otherwise determined to be invalid. As in the current Tier 

2 program as well as other 40 CFR part 80 fuel programs, if this occurs, we are 

requiring that both the seller and purchaser will have to adjust their sulfur 

calculations to reflect the proper credits and either party (or both) could be 

determined to be in violation of the standards and other requirements if the adjusted 

calculations demonstrate noncompliance with the 10 ppm standard.

Sulfur credits must be transferred directly from the refiner or importer 

generating them to the party using them for compliance purposes. This ensures that 

the parties purchasing them are better able to assess the likelihood that the credits 

are valid. As proposed, we are also finalizing an exception for the case where a 

credit generator transfers credits to a refiner or importer who inadvertently cannot 

use all the credits. In this case, the credits can be transferred a second time to 

another refiner or importer. After the second trade, the credits must be used or they 

will expire. Allowing a maximum of two trades is consistent with other recent fuel 

programs and we believe it is sufficiently flexible while still preserving adequate 

means for enforcement. While some commenters stated that they believe the twotrade maximum is not necessary given the fact that credits are only being traded 

within a small part of industry, we believe that unlimited trading could result in an 

unenforceable program and potentially lead to problems with invalid credit trading. 

Given the widespread use of credit trading between different companies under the 

Tier 2 program despite this provision, there appears to already be sufficient 

flexibility in the program. We received comments requesting that we clarify that 

intra-company trading will continue to be unlimited as it is in the existing Tier 2 

ABT program. Intra-company trading will in fact remain unlimited, and we have 

added language to the final Tier 3 regulations to clarify this.

There are currently no prohibitions against brokers facilitating the transfer 

of credits from one party to another. Any person can act as a credit broker, 

regardless of whether such person is a refiner or importer, as long as the title to the 

credits is transferred directly from the generating refiner or importer to the using 

refiner or importer. This prohibition on outside parties taking ownership of credits 

was promulgated in response to problems encountered during implementation of the 

unleaded gasoline program, and has since been extended to subsequent fuels 

rulemakings. We continue to believe that maintaining this prohibition will allow 

for maximum program enforceability and consistency with all of our other ABT 

programs for mobile sources and their fuels.
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6. ABT Provisions for Small Refiners and Small Volume Refineries

Consistent with our proposal, approved small refiners and small volume 

refineries must comply with the 10 ppm annual average standard by January 1, 

2020, which allows for an additional three years for compliance. This is the 

primary form of relief offered to small refiners and small volume refineries under 

the Tier 3 gasoline sulfur program (discussed further in Section V.E, below). 

Approved small refiners and small volume refineries may continue to generate 

credits for overcomplying with the 30 ppm Tier 2 standard before January 1, 2020. 

Prior to January 1, 2017, credits generated by small refiners and small volume 

refineries can be traded/sold to non-small refiners for use by December 31, 2019,

and the credit revenues could be used to help offset their Tier 3 investments.

When the Tier 3 program begins on January 1, 2017, small refiners and 

small volume refineries may continue to generate credits for overcompliance with 

the 30 ppm sulfur standard (as they will still be subject to the Tier 2 standards 

through December 1, 2019), or they may generate credits for overcompliance with 

the Tier 3 10 ppm sulfur standard. We are finalizing that small refiners and small 

volume refineries must designate their credits as being generated for either the Tier 

2 or Tier 3 ABT program, as proposed. Credits designated and generated as Tier 2 

credits may only be traded with other small refiners and small volume refineries 

(and these credits may only be used for compliance through December 31, 2019). 

However, credits designated and generated as Tier 3 credits may be traded with 

non-small refiners as well. Additionally, from January 1, 2017 through December 

31, 2019, if a small refiner’s annual average sulfur level is below 10 ppm, they may

elect to split the designation and generation of credits between both the 10 ppm and 

30 ppm standards (without double-counting). For example, in 2017, a small refiner 

with an annual gasoline sulfur average of 8 ppm could generate 20 ppm-volume 

Tier 2 credits (30 ppm-10 ppm) that could be used by other small refiners and small 

volume refineries, or banked by the refinery for future Tier 2 compliance. This 

small refiner would also generate 2 ppm-volume Tier 3 credits (10 ppm-8 ppm) that 

could be sold to refiners and importers subject to Tier 3, or banked by the refiner for 

future Tier 3 compliance. 

7. Deficit Carryforward

Under the final Tier 3 sulfur program, we are finalizing deficit carryforward 

provisions similar to the existing Tier 2 program, whereby an individual refinery

that does not meet the 10 ppm standard in a given year may carry a credit deficit 

forward for 1 year. Under this deficit carryforward allowance, the refinery will 

have to make up the credit deficit and come into compliance with the Tier 3 sulfur 

standard the next calendar year. We received comments expressing concern that it 

will be more challenging for refineries to make up their credit deficit in one year 

with a 10 ppm sulfur standard, and requesting that the deficit carryforward 

allowance be extended to two or three years. We disagree with these comments 
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primarily because of concerns with the enforceability of allowing for a deficit 

beyond one year. In addition, we believe that an extended deficit carryforward will 

further delay Tier 3 sulfur reductions. While we acknowledge that there might be 

an increased hurdle for some refiners to make up their own credit shortfall, we 

believe the ABT program provides ample opportunity to purchase credits from 

others. However, in recognition of unanticipated circumstances, such as where 

credits are unavailable or are prohibitively expensive such that the refiner could not 

make up the deficit in one year, the Tier 3 hardship provisions provide EPA with 

the authority to allow for extended deficit carryforward, if a refiner’s hardship 

petition demonstrates that it meets the criteria. Thus, we are finalizing that a refiner 

could carry a deficit forward for up to 3 years only in cases of hardship situations, 

as described below in Section V.E.2.

E. Additional Program Flexibilities

1. Regulatory Flexibility Provisions

a. Small Business Regulatory Flexibility Provisions

We are finalizing several regulatory flexibility provisions for small entities 

in the fuels industry to reduce the burden that the Tier 3 program could have on 

them. As in previous fuel rulemakings, our justification for including provisions 

specific to small businesses is that these entities generally have a greater degree of 

difficulty in complying with the standards compared to other entities.

In developing the Tier 3 gasoline sulfur program, we evaluated the 

environmental need as well as the technical and financial ability of refiners and 

others in the fuel industry to meet the sulfur standards as expeditiously as possible. 

We believe it is necessary and feasible for the vast majority of the program to be 

implemented in the established time frame to achieve the air quality benefits as 

soon as possible. Based on information available from small refiners and others (as 

discussed further in the Regulatory Flexibility Analysis description in Section 

XII.C), we believe that the category of entities classified as small generally face 

unique circumstances with regard to compliance with environmental programs, 

compared to larger entities. Thus, as discussed below, we are finalizing several 

regulatory flexibility provisions for small refiners to reduce the burden that the Tier 

3 program could have on them.

Small entities as a category generally lack the resources that are available to 

larger companies to raise capital for investing in a new regulatory program, such as 

shifting of internal funds, securing of financing, or selling of assets. Small entities 

are also likely to have more difficulty in competing for any needed engineering and 

construction resources. This is because the magnitude of their projects tends to be 

both smaller and less profitable for the contracted firms. As such, we are including

provisions in today’s rule that would provide assistance for small entities in meeting 
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the 10 ppm sulfur standards. This proposed approach would allow the overall 

program to begin as early as possible; achieving the air quality benefits of the 

program as soon as possible, while helping to ensure that small entities have 

adequate time to raise capital for new fuel desulfurization equipment or to make any 

other needed changes. We also believe that small business regulatory flexibilities 

can provide these entities with additional help and/or time to accumulate capital 

internally or to secure capital financing from lenders, and could spread out the 

availability of any needed engineering and construction resources in a manner that 

they are available by the time they are needed.

i. Delayed Standards for Small Refiners

We are finalizing a compliance date of January 1, 2020 for small refiners, 

allowing small refiners to postpone compliance with the Tier 3 program for up to 

three years. Small refiners will have from January 1, 2017 through December 31, 

2019 to continue production of gasoline with an average sulfur level of 30 ppm (per 

the Tier 2 gasoline sulfur program). This delayed compliance schedule for small 

refiners is not intended as an opportunity for those refiners to increase their 

production of gasoline with sulfur levels greater than 10 ppm, but rather will help 

small refiners with compliance with the program. Since the compliance costs for 

their competitors may rise during these three years and since their gasoline will be 

sold into the same fungible market, this delay will not only provide them more lead 

time, but also financial support towards later compliance. Compliance with the 10

ppm annual average sulfur standard will begin on January 1, 2020 for small 

refiners. Further, as discussed in greater detail in Section V.D.5, a small refiner 

would be allowed to continue using Tier 2 gasoline sulfur credits through December 

31, 2019 to meet their refinery average 30 ppm sulfur standard.

ii. Refinery Gate and Downstream Caps

During the Small Business Regulatory Enforcement Fairness Act 

(SBREFA) Panel process, small refiners raised the concern that a refinery gate cap 

of 20 ppm could cause problems during a refinery turnaround or an upset because a 

cap of this level could result in a refiner not being able to produce saleable gasoline. 

The Panel likewise had concerns that a downstream cap of 25 ppm may cause 

problems for small downstream entities such as transmix processors and gasoline 

additive manufacturers. They stated it would not be feasible for transmix 

processors to install desulfurization equipment to produce gasoline that meets a 25 

ppm sulfur cap. They also stated that such a low sulfur cap could preclude certain 

necessary gasoline additives from the market whose activity depends on sulfur 

containing components. Thus, the Panel recommended that EPA assess and 

request comment on retaining the current Tier 2 refinery gate and downstream caps 

of 80 and 95 ppm, respectively, to help provide maximum flexibility and avoid 

system upsets for the entire refining and distribution system. Further, the Small 

Business Administration (SBA) and Office of Management and Budget (OMB) 
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Panel members recommended that EPA propose retaining the 80 ppm and 95 ppm 

caps. The Panel also recommended that, if EPA were to propose caps lower than 80 

and 95 ppm, the Agency request comment on additional refinery gate and 

downstream caps that are above 20/25 ppm but below 80/95 ppm. As discussed 

above, we proposed options to maintain the current 80/95 ppm caps or to lower 

them to 50/65 ppm and sought comment on a refinery gate cap of 20 ppm with a 

downstream cap of 25 ppm. We are retaining the current 80/95 ppm per-gallon 

sulfur caps in today’s final rule. For more information on today’s final per-gallon 

sulfur cap provisions and related comments, refer to Section V.C of this preamble 

and Chapter 5 of the Summary and Analysis of Comments document.

b. Small Volume Refinery Provisions

Consistent with our proposal, we are finalizing a compliance date of January 

1, 2020 for small volume refineries. Approved small volume refineries will receive 

a three-year delay (January 1, 2017 through December 31, 2019) in meeting the 10

ppm average gasoline sulfur standard, similar to the small refiner delay. During the 

development of the Tier 3 rulemaking and throughout the SBREFA process, it 

became evident that some refineries may experience higher compliance costs on a 

per-gallon basis than other refineries, and in some cases considerably higher. These 

are refineries owned by a refiner/company that would not meet the SBA definition 

of a small business. In an oversupplied gasoline market, these refineries may have 

difficulty justifying capital investments to comply with new standards. In 

recognition of this concern under the RFS program, Congress granted all refineries 

with a crude oil throughput of less than or equal to 75,000 barrels per calendar day

(bpcd) additional time to comply. Consistent with this allowance, we are including

delayed Tier 3 sulfur standards for approved small volume refineries. Overall, we 

believe that these small refineries are disproportionally impacted when it comes to 

their cost of compliance and ability to rationalize the investment costs in today’s 

gasoline market. Giving these refineries additional lead time will allow more time 

to invest in desulfurization technology, take advantage of advancements in 

technology, develop confidence in a Tier 3 credit market as a means of compliance, 

and avoid competition for capital, engineering, and construction resources with the 

larger refineries. Credit generation opportunities for approved small volume 

refineries are identical to those for small refiners, as described above in Section 

V.D. 

A refiner must apply and be approved for small volume refinery status. We 

are finalizing a small volume refinery net crude throughput of less than or equal to 

75,000 bpcd, based on the highest crude throughput for the 2012 calendar year. We 

received comment suggesting that a higher crude throughput (e.g., 90,000 bpcd) 

would be more appropriate, as the refining industry has changed since Congress set 

the 75,000 bpcd throughput limit for small refineries in the RFS program. In 
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analyzing various crude throughput maximums between 75,000 and 90,000 bpcd, 

we do not believe it is appropriate or necessary to increase the threshold beyond 

what was previously set by Congress. The 75,000 bpcd limit set by Congress was 

to recognize those refineries that would have difficulty with compliance with a 

rulemaking (from both a cost and feasibility standpoint), raising this limit would go 

beyond Congress’ intent.

2. Provisions for Refiners Facing Hardship Situations

We are finalizing hardship provisions that are intended to accommodate a 

refiner’s inability to comply with the 10 ppm sulfur standard at the start of the Tier 

3 program, and to deal with unforeseen circumstances that may occur at any point 

during the program. These provisions, which are similar to those in existing fuels 

programs, are available to all refiners, small and non-small, though relief will be

granted on a case-by-case basis following a showing of certain requirements; 

primarily that compliance through the use of credits is not feasible. Any hardship 

waiver granted will not be a total waiver of compliance; rather, a hardship waiver 

will consist of short-term relief that will allow a refiner facing a hardship situation 

to, for example, receive additional time to comply. EPA will determine appropriate 

hardship relief based on the nature and degree of the hardship, as presented by the 

refiner in its hardship application, and on our assessment of the credit market at that 

time. Further, as discussed above in Section V.D.7, hardship waivers could grant 

relief in the form of additional deficit carryforward for up to three years, depending 

on the level of hardship and the status of the credit market. A detailed description 

of the requirements for applying for a hardship waiver is located in the regulations 

at 40 CFR 80.1625.

We do not anticipate a great need for hardship relief, given the flexibilities 

offered as part of the Tier 3 program and an expected robust credit trading market. 

Nevertheless, we are finalizing hardship provisions in this action as a failsafe for 

unforeseen circumstances, or should credits become scarce or prohibitively 

expensive.

a. Temporary Waivers Based on Unforeseen Circumstances

We are finalizing a provision to allow for temporary waivers based on 

unforeseen circumstances. EPA would, at our discretion, permit a refiner to seek a 

temporary waiver from the Tier 3 sulfur standards under certain rare circumstances. 

This waiver provision is intended to provide refiners relief in unanticipated 

circumstances - such as a refinery fire or a natural disaster (i.e., force majeure) -

that cannot be reasonably foreseen now or in the near future. Under this provision, 

a refiner can seek a hardship waiver for relief if it can demonstrate that the 

magnitude of the impact is so severe as to require such an extension. A refiner 

would need to show that: (1) the waiver is in the public interest; (2) the 

nonconformity is unavoidable; (3) it will meet the proposed Tier 3 standards as 
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expeditiously as possible; (4) it will make up the air quality detriment associated 

with the nonconforming gasoline, where practicable; and (5) it will pay to the U.S. 

Treasury an amount equal to the economic benefit of the nonconformity less the 

amount expended to make up the air quality detriment. These conditions are similar 

to those in existing fuels regulations, and are necessary and appropriate to ensure 

that any waivers granted would be limited in scope.

Such a request will be based on the refiner’s inability to produce compliant 

gasoline at the affected facility due to extreme and unusual circumstances outside 

the refiner’s control that could not have been avoided through the exercise of due 

diligence. The hardship request will also need to show that other avenues for 

mitigating the problem, such as the purchase of credits toward compliance under the 

ABT program provisions, have been pursued and yet were insufficient or 

unavailable. In light of other flexibilities, including the ABT program, we expect 

that the need for such requests will be rare.

b. Temporary Waivers Based on Extreme Hardship Circumstances

In addition to the provision for short-term relief in extreme unforeseen 

circumstances, we are also finalizing a hardship provision where a refiner may

receive a hardship waiver based on severe economic or physical lead time 

limitations of the refinery to comply with the Tier 3 standards at the start of the 

program. A refiner seeking such hardship relief under this provision must

demonstrate that these criteria were met. In addition to showing that unusual 

circumstances exist that impose extreme hardship in meeting the Tier 3 standards, 

the refiner will need to show that: (1) it has made best efforts to comply, including 

through the purchase of credits; (2) the relief granted under this provision is in the 

public interest; (3) the environmental impact is acceptable; and (4) it has active 

plans to meet the requirements as expeditiously as possible. We expect that 

hardship relief requests under this provision will mostly be applicable at the 

beginning of the Tier 3 program, when refiners are making their investments to 

comply. If hardship relief under these circumstances is approved, we expect to 

impose appropriate conditions to ensure that the refiner is making best efforts to 

achieve compliance offsetting any loss of emission control from the program. 

We believe that providing short-term relief to those refiners that need 

additional time due to hardship circumstances will help to facilitate the adoption of 

the overall Tier 3 program for the majority of the industry. However, we do not 

intend for hardship waiver provisions to encourage refiners to delay planning and 

investments they would otherwise make. Again, because of the flexibilities of the 

overall Tier 3 program, especially the ABT program, we expect the need for 

additional relief to be rare.
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F. Compliance Provisions

This section describes the compliance provisions of today’s program. For 

the most part, the Tier 3 sulfur standards simply reflect a lowering of the current 

Tier 2 sulfur standards. Thus, we are retaining most of the same compliance 

provisions as the current Tier 2 program, with exceptions as noted. However, we 

also proposed and sought comment on several fuel program regulatory streamlining 

measures, including a broader program redesign to streamline the reformulated 

gasoline and anti-dumping regulations.434 As discussed below, some of these 

streamlining measures will also impact the Tier 3 sulfur compliance provisions. 

1. Registration, Reporting, and Recordkeeping Requirements

Registration, recordkeeping, and reporting are necessary to track compliance 

with the Tier 3 standards and the ABT program. 

a. Registration Requirements

Refiners, importers, and anyone acting as a refiner (e.g., a terminal with 

blending or other refining operations) who expects to produce or import gasoline 

must register each of its facilities with EPA by June 1, 2016, or six months prior to 

producing gasoline meeting the Tier 3 standards and/or participating in the credit 

program. Manufacturers of denaturants that are designated as suitable for use in the 

manufacture of DFE that meets federal requirements must also register each of their

facilities with EPA by June 1, 2016, or six months prior to producing denaturant 

that is so designated.435 Manufacturers of pentane designated as suitable for use by

blenders into previously certified gasoline (PCG) subject to the Tier 2 program 

must register each of their facilities with EPA prior to manufacturing pentane for 

such downstream blending.436 Manufacturers of pentane for use by blenders of 

pentane into PCG subject to the Tier 3 program must register each of their facilities

with EPA by June 1, 2016, or six months prior to producing such pentane. After the 

Tier 3 program begins on January 1, 2017, any non-registered parties must register 

at least three months prior to producing gasoline, participating in the credit market,

producing denaturant designated as suitable for use in the manufacture of DFE that 

meets federal requirements, or producing pentane for downstream blending into 

PCG under the Tier 3 program. Consistent with the existing registration 

 

434 For more information on Part 80 regulatory streamlining options, refer to Section VI.

435 As discussed in section V.I. of this preamble, the use of denaturants that are so designated enables 

DFE manufacturers to use streamlined provisions to demonstrate compliance with the Tier 3 sulfur 

requirements for DFE.

436 The provisions for downstream blending of pentane into gasoline described in section VI.A.3. 

will become effective 60 days after the publication of this rule and may be used for gasoline subject 

to the Tier 2 program requirements as well as gasoline subject to the Tier 3 program requirements.
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requirements for butane blenders, pentane blenders must comply with the fuel 

registration requirements under the fuel and fuel additives registration program of 

40 CFR part 79. Most refiners, importers, and ethanol producers and some ethanol 

denaturant manufacturers are currently registered with EPA under other 40 CFR 

part 80 fuels programs. All manufacturers of gasoline additives for use in highway

vehicles are already required to be registered with EPA under 40 CFR part 79 fuel 

and fuel additives program. Parties who are already registered do not have to 

register again.

The same basic forms currently being used for existing fuels programs will 

be used for Tier 3 registration. These forms are well known in the regulated 

community and are simple to fill out. Upon receipt of a completed registration 

form, EPA will issue a unique 4-digit company identification number and a unique 

5-digit facility identification number. As with existing fuels programs, these 

numbers will be required for all reports sent to EPA and for PTDs.

Registrations do not expire and do not have to be renewed; however, 

registered parties are responsible for notifying us of any change to their company or 

facility information.

An entity’s registration must include a corporate name and address 

(including the name, telephone number, and e-mail address of a corporate contact

person); and, for each facility operated by the entity:

 Type of facility (e.g., refinery, import facility, pipeline, terminal, 

transmix facility, etc.)

 Facility name

 Physical location

 Name, telephone number, and e-mail address of a corporate contact 

person

b. Reporting Requirements

Refiners and importers must submit annual reports demonstrating their 

compliance with the Tier 3 standards, and on the generation, use, and transfer of 

sulfur credits at each of its refineries or import facilities. Similar to our other sulfur 

programs, refiners and importers must submit data on individual batches of gasoline 

(including batch volume and sulfur content). Based on our experience with existing 

gasoline and sulfur-based programs, we believe that requiring annual reports and 

individual sulfur batch data provides an effective means of monitoring compliance 

with the standards and the credit program.
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Producers and importers of blender grade pentane for use by pentane 

blenders must also submit annual reports that include data on individual batches 

demonstrating compliance with the quality requirements for blender grade pentane 

and batch volume. 

We proposed that producers and importers of DFE and other oxygenates 

would be required to submit an annual report that includes the total volume of 

DFE/oxygenate produced and an attestation that all batches met the proposed fuel 

quality requirements. We continue to believe that such annual reports are important 

enforcement and compliance assurance mechanism and thus are finalizing the 

proposed annual reporting requirements for oxygenate producers and importers. 

Tier 3 reports will be due annually on March 31, on forms as required by

EPA.

c. Recordkeeping Requirements

Similar to current EPA fuels programs, refiners and importers must retain all 

records that demonstrate compliance with the Tier 3 program, including the ABT 

program. 

Manufacturers of DFE and other oxygenates must keep records for five 

years on individual batches of DFE/oxygenate (including batch volume,, denaturant 

concentration, and sulfur test results or other records to demonstrate compliance 

with the Tier 3 sulfur requirements as applicable).437

Manufacturers of ethanol denaturant that is designated as suitable for use in 

the manufacture of DFE that meets federal requirements must keep records on 

individual batches of such denaturant including batch volume, and sulfur content. 

Manufacturers of pentane that is designated as suitable for use for blending 

into PCG must keep records on individual batches of such pentane including batch 

volume, sulfur content, benzene content, olefin content, aromatic content, C6 and 

higher hydrocarbon content, and purity as applicable.

Manufacturers of gasoline additives for use in highway vehicles must keep 

records on individual batches of such additives including batch volume and additive 

production quality control activities which demonstrate that the sulfur content of 

additive production batches complies with the Tier 3 sulfur requirements. We 

 

437 As discussed in section V.G. of this preamble, DFE manufacturers may demonstrate compliance 

with Tier 3 sulfur requirements either by testing each batch or mathematically using volumetric 

blend records and product transfer documents from the denaturants used provided such denaturants 

are from a registered denaturant producer.
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expect that such records would include the results of periodic sulfur testing but not 

necessarily testing on each production batch.

All parties in the gasoline, DFE, ethanol denaturant, pentane, and gasoline 

additive production and distribution system subject to the Tier 3 sulfur program are 

also required to keep records of all PTDs and records of any quality assurance 

programs. Records must be retained for five years. For credit transactions, records 

must be retained for five years from the usage date. Records must be made 

available to EPA on request; if electronic records are kept, hard copies must be 

made available upon request.

Information submitted to EPA may be claimed as confidential business 

information (CBI). Parties making such a claim must follow all reporting guidance 

and clearly mark the information being claimed as proprietary. EPA will treat 

information covered by such a claim in accordance with the regulations at 40 CFR 

part 2 and other Agency procedures for handling proprietary information.

2. Sampling and Testing Requirements

Under the Tier 2 program, a sulfur concentration must be determined for 

every batch of gasoline. We are retaining this requirement under the Tier 3

program. As with the existing Tier 2 program, this every-batch testing requirement 

will be required to occur prior to the batch leaving the refinery. We are also

retaining the Tier 2 sampling, testing, and sample retention requirements in today’s 

final rule. Additionally, as discussed below in Section VI, we have included

performance based measurement standards that will allow refiners to use alternate 

test methods for measuring sulfur if they so choose.

We proposed that manufacturers of DFE would be required to test each 

individual batch of DFE for its sulfur content. In response to comments, we are 

finalizing an alternative means for DFE manufacturers to demonstrate compliance 

with the Tier 3 sulfur requirements in addition to per batch testing.438 We anticipate 

that DFE manufacturers will typically use this alternative means in the place of per 

batch sulfur testing.

As discussed above, manufacturers of additives for use in highway gasoline 

vehicles must maintain records of additive production quality control activities 

which demonstrate that the sulfur content of additive production batches complies

with the Tier 3 sulfur requirements. We expect that periodic sulfur testing will be 

needed to comply with this requirement but not necessarily testing on each additive 

production batch. Manufacturers of pentane that is designated as suitable for use 

 

438 The alternative means of demonstrating compliance with the Tier 3 sulfur requirements for DFE 

manufacturers is discussed in section V.G. of this preamble
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by blenders into PCG must test every batch to demonstrate compliance with the

requirements sulfur content, benzene content, olefin content, aromatic content, C6 

and higher hydrocarbon content, and purity as applicable. Blenders of pentane into 

gasoline must conduct periodic sampling and testing of the pentane they receive 

from each separate pentane supplier to demonstrate that the pentaene is compliant 

with the applicable compositional requirements.

3. Small Refiner Compliance

To qualify for small refiner status under the Tier 3 program, a refiner must 

apply by June 1, 2016. As with our other existing EPA fuels programs, we are 

continuing to use the Small Business Administration definition of a small refiner: 

1,500 employees (company-wide). To qualify for small refiner status under Tier 3, 

a small refiner must also meet the following additional criteria:

 The refiner must have produced gasoline from crude oil during the 2012

calendar year.

 The refiner must have owned and operated the refinery during the period 

from January 1, 2012 through December 31, 2012. New owners that 

purchased a refinery after that date will have done so with full 

knowledge of the proposed Tier 3 regulations, and should have planned 

to comply along with their purchase decisions. As with existing fuel 

programs, a refiner that restarts a refinery in the future may be eligible 

for small refiner status. Thus, a refiner restarting a refinery that was shut 

down or non-operational during calendar year 2012 can apply for small 

refiner status. In such cases, we will judge eligibility under the 

employment and crude oil capacity criteria based on the most recent 12 

consecutive months prior to the application, unless we conclude from 

data provided by the refiner that another period of time is more 

appropriate. However, this is limited to a company that owned the 

refinery at the time that it was shut down. New purchasers will not be 

eligible for small refiner status for the same reasons described above.

 The refiner must have had 1,500 employees or less based on the average 

number of employees for all pay periods from January 1, 2012 through 

December 31, 2012 for all subsidiaries, parent companies (i.e., any

company or companies with controlling interest), and joint ventures.

 The refiner must have had a crude oil capacity less than or equal to 

155,000 bpcd during the 2012 calendar year.

A refiner applying for small refiner status must apply and provide EPA with 

several types of information, as specified in the regulations, by June 1, 2016. All 

refiners seeking small refiner status under this program must apply for small refiner 
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status, regardless of whether the refiner has been approved for small refiner status 

under another fuel program. As with applications for relief under other rules, 

applications for small refiner status under this final rule that are later found to 

contain false or inaccurate information will be void ab initio.

Requirements for small refiner status applications:

 The total crude oil capacity as reported to the Energy Information 

Administration (EIA) of the U.S. Department of Energy (DOE) for the 

most recent 12 months of operation. This includes the capacity of all 

refineries controlled by a refiner and by all subsidiaries and parent 

companies and joint ventures. We will presume that the information 

submitted to EIA is correct. (In cases where a company disagreed with 

this information, the company may petition EPA with appropriate data to 

correct the record when the company submitted its application for small 

refiner status. EPA will accept such alternate data at its discretion.)

 The name and address of each company location where employees 

worked during the 2012 calendar year; and the number of employees at 

each location during this time period. This includes the locations and 

number of employees working at all subsidiaries, parent companies, and 

joint ventures.

 In the case of a refiner who reactivates a refinery that was either 

shutdown or non-operational from January 1, 2012 through December 

31, 2012, the name and address of each company location where 

employees worked since the refiner reactivated the refinery and the 

average number of employees at each location for each calendar year 

since the refiner reactivated the refinery.

 The type of business activities carried out at each location.

 Contact information for a corporate contact person, including: name, 

mailing address, phone and fax numbers, e-mail address.

 A letter signed by the president, chief operating officer, or chief 

executive officer of the company (or a designee) stating that the 

information contained in the application is true to the best of his/her 

knowledge and that the company owned the refinery as of January 1, 

2012.

An approved small refiner that exceeds the employee count or crude 

capacity criteria due to merger with, acquisition by, or the acquisition of another 

entity will lose its small refiner status. In situations where a small refiner loses its 

small refiner status due to merger with a non-small refiner, acquisition of another 
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refiner, or acquisition by another refiner, we are finalizing provisions that are 

similar to those in our existing fuels programs to allow up to an additional 30 

months of lead time to comply with the Tier 3 program after the disqualifying 

event, but no later than December 31, 2019.

439

 This 30 months of additional lead 

time will only apply to refineries that were previously subject to small refiner relief, 

as we believe there will be no adverse environmental impact because of the preexisting relief provisions that applied to the small refiner. A refiner will also lose 

its small refiner status if it ceases to process crude oil.

Our intent has been, and continues to be, limiting the small refiner relief 

provisions to a small subset of refiners that are challenged, as discussed above. 

However, it is also our intent to avoid stifling normal business growth. Therefore, 

an approved small refiner who exceeds the employee count or crude oil capacity

criteria through normal business practices may retain its small refiner status. 

Further, in the sole case of a merger between two approved small refiners, such 

refiners will be permitted to retain their individual small refiner status. Additional 

financial resources would not typically be provided in the case of a merger between 

two small refiners. Small refiner status for the two entities of the merger would not 

be affected; hence the original compliance plans of the two refiners should not be 

impacted. Moreover, no environmental detriment will result from the two small 

refiners maintaining their small refiner status within the merged entity as they 

would have likely maintained their small refiner status had the merger not occurred.

4. Small Volume Refinery Compliance

In the case of small volume refineries, the application process for 

qualification is similar to that of a small refiner. A refiner that is both a small 

refiner and owns a small volume refinery need not apply for small volume refinery

status; the small refiner application is all that is needed. Small refineries must have 

a net crude throughput threshold of no more than 75,000 bpcd based on the highest 

throughput in calendar years 2011 or 2012 as the basis for receiving small volume 

refinery status.

Refiners must include the following in their applications for small volume 

refinery status:

 Proof that the refiner produced gasoline from crude oil during the 2012

calendar year.

 Proof that the refiner owned and operated the refinery during the period 

from January 1, 2012 through December 31, 2012.

 

439 See, for example, 69 FR 39051 (June 29, 2004).
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 The refinery’s total crude throughput as reported to EIA for each of 

calendar years 2011 and 2012. Again, we will presume that the 

information submitted to EIA is correct. In cases where a refiner 

disagrees with this information, the refiner may petition EPA with 

appropriate data to correct the record when the refiner submits its 

application for small volume refinery status. EPA will accept such 

alternate data at its discretion.

 Contact information for a corporate contact person, including: name, 

mailing address, phone and fax numbers, e-mail address.

 A letter signed by the president, chief operating officer, or chief 

executive officer of the company (or a designee) stating that the 

information contained in the application is true to the best of his/her 

knowledge and that the company owned the refinery as of January 1, 

2012.

5. Attest Engagements, Violations, and Penalties

In today’s final rule we are retaining the existing Tier 2 requirements for 

attest engagements for generation of both early and standard credits, use of credits, 

and compliance with the proposed program, using the procedures currently used in 

existing EPA fuels programs for attest engagements. The violation and penalty

provisions applicable to today’s Tier 3 program will be very similar to the 

provisions currently in effect in other gasoline programs as well.

6. Special Fuel Provisions and Exemptions

The following paragraphs discuss several provisions and exemptions from 

the Tier 3 gasoline sulfur standards in special circumstances.

a. Gasoline Used in Military Applications

In both our diesel fuel program and the Tier 2 gasoline sulfur program, we 

provided an exemption for fuel used in tactical military vehicles and nonroad 

engines and equipment with a national security exemption (NSE) from the vehicle 

and engine emissions standards. Due to national security considerations, some of 

EPA’s existing regulations allow the military to request and receive NSEs for 

vehicles, engines, and equipment from emissions regulations if the operational 

requirements for such vehicles, engines, or equipment warrant such an exemption. 

Fuel used in these applications is also exempt if it is used in tactical military 

vehicles, engines, or equipment that are not covered by an NSE but, for national 

security reasons (such as the need to be ready for immediate deployment overseas), 

need to be fueled on the same fuel as those with an NSE. We are including this 

exemption in the Tier 3 gasoline program.
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b. Gasoline Used in Research, Development, and Testing

Similar to existing EPA fuels programs, we are finalizing provisions to 

allow for requests for an exemption from the Tier 3 standards for gasoline used for 

research, development, and testing purposes (“R & D exemption”). We recognize 

that there may be legitimate research programs that require the use of gasoline with 

sulfur levels greater than those allowed under the Tier 3 program. Thus, we are 

including provisions for obtaining an exemption from the prohibition against 

persons producing, distributing, transporting, storing, selling, or dispensing gasoline 

that does not meet the Tier 3 gasoline sulfur standards, where such fuel is necessary 

to conduct a research, development, or testing program.

Parties seeking an R & D exemption must submit an application for 

exemption to EPA that describes the purpose and scope of the program, and the 

reasons why the noncompliant gasoline is necessary. Upon presentation of the 

required information, an exemption may be granted at the discretion of EPA, with 

the condition that EPA can withdraw the exemption in the event the Agency

determines the exemption is not justified. In addition, an exemption based on false 

or inaccurate information will be considered void ab initio. Gasoline subject to an 

exemption will be exempt from certain provisions of this rule, including the sulfur 

standards, provided certain requirements are met. These requirements include the 

segregation of the exempt gasoline from non-exempt gasoline, identification of the 

exempt gasoline on PTDs, and pump labeling.

c. Gasoline for Export

Gasoline produced for export, and that is actually exported for use in a 

foreign country, will be considered exempt from the fuel content standards and 

other requirements of the Tier 3 gasoline sulfur program. In order to exclude 

exported gasoline, refiners must retain records to demonstrate that the gasoline was 

exported. Such gasoline must be designated by the refiner, and the PTD must state 

that the gasoline is for “export only”; otherwise, the gasoline will be considered as 

intended for use in the U.S. and subject to the Tier 3 standards. Gasoline intended 

for export must be segregated from all gasoline intended for use in the U.S. 

Distributing or dispensing such fuel for domestic use will be illegal.

d. Other Special Provisions and Exemptions

Additionally, in existing EPA fuels programs we have included exemptions 

for racing fuel and for fuel used in the U.S. territories of Guam, American Samoa, 

and the Northern Mariana Islands; we are finalizing such exemptions for the Tier 3

program as well.
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G. Standards for Oxygenates (Including Denatured Fuel Ethanol) and 

Certified Ethanol Denaturants

The following discussion is focused on the standards finalized today for 

denatured fuel ethanol (DFE) because DFE is the predominant gasoline oxygenate 

currently in-use.440 These standards also apply to other gasoline oxygenates.441

1. Sulfur Standard

The Tier 2 gasoline requirements include the prohibition on blending 

gasoline with DFE that has sulfur content higher than 30 ppm.442 This requirement 

reflects the 30 ppm refinery gasoline average sulfur requirement under the Tier 2 

program. Consistent with the approach under the Tier 2 program and our proposed 

10 ppm refinery average sulfur standard for gasoline under the Tier 3 program, we 

proposed that producers of DFE for use by oxygenate blenders would be required to 

meet a 10 ppm sulfur cap beginning January 1, 2017. We proposed requiring DFE 

producers to test each batch of DFE to demonstrate compliance with the sulfur 

content standard, and to retain and provide batch reports to EPA. 

The Renewable Fuels Association (RFA) commented that if EPA were to 

accept current industry practices used to assure that DFE is compliant with the state 

of California’s 10 ppm sulfur cap for DFE in place of per-batch sulfur testing and 

reporting there would be no additional burden to ethanol producers in meeting a 10 

ppm sulfur cap.443 In 2002, RFA conducted an industry survey that demonstrated 

DFE manufacturers were meeting California’s 10 ppm maximum sulfur content

requirement. Since then, RFA has recommended to the ethanol industry that all 

DFE meet this California requirement and indicated that ethanol producers are 

adhering to this recommendation. Other commenters also stated that DFE 

manufacturers have been producing DFE that complies with California 

specifications because of logistical difficulties in segregating ethanol destined for 

California from other destinations.

An environmental organization commented that the proposed 10 ppm sulfur 

cap for DFE was necessary to ensure that the Tier 3 program benefits are actually

realized. Refiners commented that requiring DFE to meet a 10 ppm sulfur cap was 

essential to facilitating their compliance with the Tier 3 gasoline sulfur 

 

440 An importer of biofuels commented that EPA should clarify that the standards for DFE will apply 

to importers as well as domestic producers. The regulations finalized today specifically state that the 

standards for denatured fuel ethanol apply to importers are will as domestic producers of DFE.

441 Public comments supported our proposal to apply the same standards to all gasoline oxygenates.

442 40 CFR 80.385(e).

443 RFA requested regulatory relief from the proposed batch testing and reporting requirements as 

discussed in preamble Section V.G.4. 
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requirements. In demonstrating compliance with the 10 ppm average gasoline 

sulfur standard finalized today, gasoline refiners and importers may adjust the 

sulfur levels in the gasoline and BOBs that they produce/import to account for the 

downstream addition of ethanol.444 Therefore, the sulfur level of DFE has a direct 

effect on the extent of the desulfurization measures that a refiner/importer will have 

to undertake to comply with the gasoline sulfur standards finalized today. A refiner 

commented that if the sulfur standard for DFE was left at its current level of 30 

ppm, greater capital investments would be needed to adjust and lower the sulfur 

content of other gasoline blending streams to prevent violation of the ultimate 10 

ppm annual average standard.

Some ethanol producers and Growth Energy (representing ethanol 

producers) commented that DFE should be subject to an annual average sulfur 

standard and be able to participate in the averaging banking and trading (ABT) 

program that is available to refiners and importers of gasoline. Some ethanol 

producers commented that they should be allowed to participate in the ABT 

program as a means of offsetting the additional cost of the proposed per-batch 

sulfur testing and reporting requirements.

EPA believes that requiring DFE to comply with a 10 ppm sulfur cap is the 

most appropriate means of ensuring that finished gasoline blends attain the sulfur 

control goals of the Tier 3 program. Therefore, today’s rule finalizes a 10 ppm 

sulfur cap for DFE. Because essentially all (if not all) DFE already meets 

California’s 10 ppm sulfur standard, EPA believes that the implementation of a 

federal 10 ppm sulfur cap for DFE would not result in a significant increased 

burden for ethanol producers.445 Neat ethanol produced with standard quality 

control practices should have negligible sulfur content. Denaturants with 

sufficiently low-sulfur content to facilitate compliance with the 10 ppm sulfur cap 

for DFE are widely available. Allowing DFE to exceed 10 ppm would result in the 

use of higher-sulfur denaturants, thereby increasing gasoline refiner capital costs to 

install desulfurization equipment. As discussed in Section V.D.3 of this preamble, 

there are several reasons why we do not believe that it is appropriate to expand the 

ABT provisions to include ethanol producers and importers. Furthermore, as 

discussed in Section V.G.4, sulfur testing on each batch of DFE will not be required 

provided that the DFE producer or importer demonstrates compliance with the 10 

ppm sulfur cap for DFE with volumetric blending records, whereas an average 

standard would require testing of every batch. We anticipate that DFE producers 

 

444 Accounting for the effect of oxygenate added downstream of the refinery or import facility in 

demonstrating compliance with the average gasoline sulfur standard is addressed in regulations 

finalized today at §80.1603(d). See Section V.C. in today’s preamble regarding the sulfur level in 

DFE that must be used by refiners and importers in making this compliance determination. 

445 The potential for additional burden associated with demonstrating compliance with a 10 ppm 

sulfur cap is discussed in Section V.G.4.
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and importers will typically choose to demonstrate compliance with the 10 ppm 

sulfur cap using volumetric blending records rather than per-batch sulfur testing. 

Therefore, we do not anticipate that DFE producers and importers will need to 

install additional sulfur testing equipment as a result of today’s rule. Hence, there is 

no need to extend the flexibility of meeting an annual average sulfur standard and 

participation in the ABT program to ethanol producers and importers to help 

facilitate their compliance as exists for gasoline refiners.446

Comments were supportive of the proposed January 1, 2017 implementation 

date for standards applicable to DFE. Today’s action requires that importers and 

manufacturers of DFE comply with the standards finalized today beginning January

1, 2017.

2. Limitation on the Type of Ethanol Denaturant

To limit the variability in DFE composition and the associated potential 

impact on vehicle emissions, we proposed to allow the use of only certified 

gasoline, gasoline blendstocks for oxygenate blending (BOBs), and natural gasoline 

as denaturants. Commenters stated that it would be unnecessary to place additional 

limits on the types of denaturants that could be used beyond those in the ASTM 

specification for DFE. Groups representing refiners stated that EPA had not 

presented data to support that additional limitations on the types of denaturants that 

can be used (or the allowed concentrations at which they may be used) are needed 

beyond those adopted by ASTM and the State of California to address concerns 

about the potential adverse impacts on vehicle emissions performance. The ASTM 

specification for DFE requires that the only denaturants that can be used are 

gasoline, gasoline blendstocks, and natural gasoline. The State of California 

incorporated the ASTM limits on allowable denaturants into its regulations for DFE 

by reference.447 Thus, both ASTM and the State of California allow the use of 

gasoline blendstocks other than BOBs as denaturants. One refiner stated that DFE 

producers have used refinery gasoline blendstocks such as “light straight run” and

“light naphtha” as denaturants and that removing this flexibility would increase 

DFE production costs. They noted that access to this flexibility could become more 

important under a 10 ppm sulfur cap for DFE. In addition to needing to preserve 

the flexibility to use a range of gasoline blendstocks, ethanol manufacturers stated 

that EPA should consider the possibility of approving denaturants that are not 

currently allowed under the ASTM specification for DFE. One refiner stated that 

 

446 See Section V.D.3. of this preamble for additional discussion of why we are not extending the 

sulfur averaging, banking, and trading program to cover DFE manufacturers. 

447 The California Code of Regulations references ASTM D 4806-99 which limits the allowed 

denaturants to gasoline, gasoline components, and natural gasoline.
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ASTM is the appropriate technical forum for the consideration of adding new 

allowable denaturants.

EPA continues to believe that it is appropriate to implement additional 

controls to address the potential impact of fuel components in denaturants other 

than sulfur on vehicle emissions. However, we agree with the comments that it is 

not appropriate to implement additional controls on the types of denaturants that 

may be used beyond those currently adopted by ASTM and the State of California 

at this time. Therefore, in response to comments, today’s rule includes the 

requirement that only gasoline, gasoline blendstocks, and natural gasoline may be 

used to denature DFE.448 This requirement is essentially the same as the current 

ASTM and State of California specifications for the type of denaturants that may be 

used. We will continue to monitor the potential need for additional controls on 

ethanol denaturants, and may revisit this issue in the context of setting in-use 

quality specifications for E85 in the future.449 We will also continue to monitor the 

need for additional denaturants, and when appropriate EPA may undertake a future 

rulemaking to consider allowing their use.

As discussed in Section V.G.4, in order for DFE producers and importers to 

take advantage of streamlined provisions for demonstrating compliance with the 10 

ppm sulfur cap for DFE, they must only use denaturants from registered producers 

that have been demonstrated as meeting EPA compositional requirements. 

Denaturants from unregistered denaturant producers may be used by DFE producers 

provided that they test each batch of DFE to demonstrate compliance with the 10 

ppm sulfur cap for DFE.

3. Limitation on Ethanol Denaturant Concentration

To further limit the potential impact on vehicle emissions of fuel parameters 

in ethanol denaturants other than sulfur, we proposed to limit denaturant 

concentration in DFE to a maximum of 2 volume percent, which translates to 2.5 

volume percent considering rounding. We also requested comment on alternately 

adopting the additional fuel specifications currently in force for DFE in the State of 

California. While California allows a maximum denaturant content of 5 volume 

percent consistent with the industry consensus ASTM International (ASTM) 

specification for DFE, they also have maximum specifications for benzene, olefins, 

and aromatics as well as sulfur.451

 

448 Finished gasoline used as denaturant must be compliant with the applicable EPA requirements. 

449 See Section V.H. for a discussion of potential FFV in-use fuel quality requirements.

451 California Code of Regulations 13 CCR section 2262.9. ASTM International D4806-13a, 

“Standard Specification for Denatured Fuel Ethanol for Blending with Gasolines for Use as 

Automotive Spark-Ignition Engine Fuel”.
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A number of refiners and ethanol manufacturers stated that it was 

unnecessary to limit denaturant concentration beyond the 5 volume percent 

specified by ASTM. Ethanol manufacturers stated that the RFS2 program 

requirement that DFE contain no more than 2 volume percent denaturant for 

Renewable Identification Number (RIN) generation purposes already provides a 

strong incentive to keep denaturant concentration under 2 percent.

453

 However, 

they stated that the flexibility to have a slightly higher denaturant content can be 

important to ethanol producers. One ethanol producer stated that the proposed 

maximum 2 volume percent cap on denaturant concentration would provide 

insufficient tolerance given that the Alcohol and Tobacco Tax and Trade Bureau

requires a 1.96 percent minimum denaturant concentration.

454 They stated that EPA 

should provide a more reasonable tolerance to avoid inadvertent compliance issues.

A number of refiners stated that the current 5 volume percent maximum on 

denaturant concentration established by ASTM would limit concerns regarding 

components other than sulfur so that they would be unlikely to impact vehicle 

emissions performance. One refiner stated that EPA should adopt the entire 

California specifications for DFE in order to address concerns about potential 

emissions impacts of fuel components in denaturants other than sulfur. They stated 

that this would not impose an additional burden on DFE producers since logistical 

difficulties in segregating ethanol destined for California from other destinations 

has already caused producers to DFE to California specifications. 

Since we are not finalizing benzene, olefin, or aromatics specifications for 

ethanol denaturants like California, we continue to believe that it is appropriate to 

implement a more stringent limit on maximum denaturant concentration to address 

concerns about the potential impact on vehicle emissions of fuel parameters in 

ethanol denaturants other than sulfur. Setting a more stringent limit on denaturant 

concentration will ensure that harmful components such as benzene potentially

present in ethanol denaturants are adequately diluted in the finished fuel blend. We 

agree with comments that it is appropriate to provide additional flexibility for the 

allowable denaturant levels that may be used. Therefore, we are finalizing a 3.0 

volume percent maximum on ethanol denaturant concentration. This approach 

provides sufficient flexibility to DFE producers while avoiding the need to impose 

additional testing burdens on denaturant and DFE producers (e.g., for benzene and 

 

453 This RFS2 program provision is covered under the definition of renewable fuel/ethanol in 40 

CFR 80.1401. The volume of denaturant used in excess of 2 volume percent must be subtracted 

from the total volume of DFE for RIN generation purposes.

454 Alcohol and Tobacco Tax and Trade Bureau formulas require a minimum of two parts of 

approved denaturant to 100 parts of ethanol with a minimum of 195 proof ethanol.: 27 CFR Subpart 

X, Distilled Spirits for Fuel Use; ASTM International D4806-13a, “Standard Specification for 

Denatured Fuel Ethanol for Blending with Gasolines for Use as Automotive Spark-Ignition Engine 

Fuel”.
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aromatics). We will consider whether additional controls may be needed for midlevel ethanol blends and E85 in a later action. 

4. Demonstration of Compliance with the Sulfur Requirements and 

Requirements for Certified Ethanol Denaturants

To demonstrate compliance with the 10 ppm sulfur cap finalized today, we 

proposed that producers and importers of DFE would be required to test the sulfur 

content of each batch of DFE they produce. We also proposed that DFE producers 

would be required to provide batch records to EPA on an annual basis. We 

requested comment on whether to require producers of denaturants for use in DFE 

to register with EPA and to demonstrate compliance with a maximum sulfur 

specification based on the anticipated dilution with ethanol. 

Refiners stated that producers of DFE should be subject to requirements 

similar to those for gasoline refiners including batch sampling. However, refiners 

stated there would be no added value in requiring batch reports from DFE 

producers. Ethanol producers currently use certificates of sulfur analysis from 

denaturant producers and volumetric DFE blending records to assure themselves 

that when a sample of DFE is tested by the State of California that it will be found 

to be compliant with a 10 ppm sulfur cap.458 They stated that EPA should accept 

such records to demonstrate compliance with the federal 10 ppm sulfur cap for DFE 

in place of per-batch sulfur testing on DFE. Under this approach, ethanol producers 

would maintain records regarding the denaturant sulfur content and the calculations 

used to determine the sulfur content of the finished DFE. Because the sulfur 

content of neat (un-denatured) ethanol manufactured using industry standard quality

control practices should be negligible, the sulfur content of DFE is effectively 

determined by the sulfur content of denaturant used.459 Ethanol producers stated 

that they would also perform standard quality assurance activities including 

sampling incoming shipments of denaturant for sulfur content on a periodic basis. 

Ethanol producers stated that many DFE production facilities do not have on 

site sulfur testing equipment and the installation of such equipment would represent 

a substantial burden to DFE producers. Ethanol producers stated that they had 

worked with denaturant producers to ensure access to a low-sulfur stream of 

denaturants, and that it is common business practice for denaturant producers to 

provide them with information on the sulfur content of their product. Ethanol 

 

458 The State of California does not rely on industry testing and recordkeeping to help establish 

compliance with their sulfur requirements for DFE, instead choosing to focus on direct testing that 

they conduct. EPA relies on the review of industry records including those associated with tesing 

conducted by industry as well as direct testing conducted by EPA for compliance assurance.

459 Ethanol manufacturers conduct periodic sulfate testing on neat ethanol to ensure that sulfur 

contamination from the manufacturing process is negligible. 
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producers stated that sulfur test results from the ASTM Inter-laboratory Crosscheck 

Program (ILCP) for DFE illustrate that batch reporting for DFE is unnecessary. 

They noted that the ILCP data shows DFE typically has sulfur content of 1 to 5 

ppm. 

Ethanol producers stated that requiring denaturant manufacturers to register 

with EPA would limit the number of denaturant suppliers willing to supply the 

ethanol industry. They stated that it is inappropriate to require a natural gasoline 

producer to register in order to supply product for DFE, because they are not 

required to register in order to supply the same product to a gasoline blender.

EPA agrees that is appropriate to finalize requirements for the 

demonstration of compliance with the 10 ppm sulfur cap for DFE that are based on 

current industry practices rather than requiring sulfur testing on each batch of 

DFE.460 We agree that that potential contribution to the sulfur content of DFE other 

than from the addition of denaturants can be adequately addressed by the retention 

of production quality control records by the ethanol manufacturer. We agree that it 

is most appropriate to place the primary focus of compliance assurance on the 

denaturant manufacturers given the denaturant typically contributes the majority of 

the sulfur to the finished DFE. Therefore, we are finalizing streamlined provisions 

that DFE producers and importers may use in demonstrating compliance with the 

10 ppm sulfur cap for DFE as an alternative to testing each batch of DFE for its 

sulfur content. These streamlined provisions are based on the use of denaturant 

batch sulfur testing conducted by denaturant producers who have registered with 

EPA and certified the denaturant they produce as meeting EPA requirements.

461

 

Uncertified denaturants from unregistered denaturant producers may be used by

DFE producers provided that they test each batch of DFE to demonstrate 

compliance with the 10 ppm sulfur cap for DFE.462

DFE manufacturers that use denaturants that have been certified and 

designated on the denaturant product transfer document (PTD) as suitable for use in 

the manufacture of DFE that meets federal requirements will be able use PTDs for 

the denaturants used and volumetric blending records which show that the 

denaturant was added at 3.0 volume percent or less in demonstrating compliance 

 

460 Per-batch sulfur testing for other potential oxygenates will be required to demonstrate compliance 

with the 10 ppm sulfur cap. EPA may consider amending the requirements for other potential 

oxygenates in a later rulemaking based on additional information that we might receive.

461 Certified denaturant producers and importers will be required to register with EPA as a certified 

denaturant producer or importer by November 1, 2016, or 60 days before introducing certified 

denaturant into commerce, whichever is earlier. 

462 The limitation on the types of denaturants that may be used and the maximum concentration at 

which a denaturant may be used discussed in Section V.G.2 and 3 would apply regardless of whether 

a denaturant from a registered or non-registered denaturant manufacture are used.
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with the 10 ppm sulfur cap for DFE in lieu of per-batch sulfur testing of DFE. The 

sulfur content of “neat” (i.e. un-denatured) ethanol may be assumed to be negligible 

for the purposes of demonstration of compliance using volumetric blending records 

provided that the DFE manufacturer maintains quality control records that 

demonstrate this assumption is justified. Today’s rule also requires that DFE 

manufacturers conduct quality assurance to demonstrate affirmative defenses to 

presumptive liability.

463

 Producers and importers of DFE must initiate a PTD to 

accompany each batch of DFE which states that it meets federal standards. 

Denaturant manufacturers are accustomed to providing certificates of sulfur 

analysis to DFE manufacturers. Therefore, we believe that the requirements 

finalized today for denaturant manufacturers to conduct per-batch sulfur testing, 

initiate a product transfer document stating that denaturant is suitable for use in 

manufacturing DFE that meets federal requirements, retain records, and register 

with EPA will not represent a substantial new burden. DFE manufacturers who use 

the mathematical method to demonstrate compliance with DFE sulfur requirements 

must only use certified denaturants from registered denaturant manufacturers. 

Registering with EPA will be a one-time act, as will be the necessary modifications 

to denaturant product transfer documents. Thus, the requirement to register with 

EPA should not be a serious impediment for a manufacturer to enter the denaturant 

supply market. We believe that it is necessary to require denaturant manufacturers 

to register with EPA in order to facilitate compliance oversight. EPA needs to be 

able identify all manufacturers of denaturants in order to periodically audit their 

records, and to recognize potential denaturants in the system that are incorrectly 

designated as a certified denaturant appropriate for use in manufacturing DFE that 

meets federal sulfur requirements. Denaturant manufacturers that supply their 

product to refiners for use in the manufacture of gasoline are not required to register 

with EPA because, unlike the DFE manufacturers, refiners are responsible for 

testing the final gasoline they produce.

As is current practice today, we anticipate that ethanol manufacturers will 

negotiate the specific sulfur level they require from denaturant manufacturers to 

facilitate compliance with the 10 ppm sulfur cap for DFE taking into consideration 

what level of compliance margin a given manufacturer feels is necessary. We 

believe that it is appropriate to allow this practice to continue. We understand that 

ethanol manufacturers currently require denaturant manufacturers to provide a 

product with a sulfur content of 120 ppm or less in order to ensure that DFE that 

contains 5 volume percent denaturant can comply with California’s 10 ppm sulfur 

cap for DFE. Thus, we expect that denaturant manufacturers will not need to 

 

463 Such quality assurance practices include periodic calibration of the denaturant blending 

equipment to ensure that denaturants are not added in excess of 3.0 volume percent.
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change the sulfur content of the denaturant they manufacture in order to comply

with the requirements finalized today.

Manufacturers of certified denaturants used by DFE producers that employ

the volumetric blending record method in demonstrating compliance with the sulfur 

requirements for DFE must retain per batch sulfur test data on the denaturants they

produce to demonstrate that the sulfur content of the denaturant will not cause the 

sulfur content of DFE to exceed 10 ppm when added to neat ethanol at 3.0 volume 

percent. The sulfur content of the certified denaturant must be stated on the PTD 

and must be no greater that 330 ppm. Any sample of denaturant which is

designated as appropriate for use in manufacturing DFE that meets federal 

requirements, that is found by EPA to have sulfur content above 330 ppm will be 

deemed to be noncompliant, and the denaturant manufacturer may be liable for the 

associated penalties. A denaturant with a sulfur content of 330 ppm when used at 

3.0 volume percent would result in a sulfur content of the finished DFE of 10 ppm. 

Certified denaturant manufacturers may represent the denaturant they produce as 

having a sulfur content of less then 330 ppm on the PTD. In such cases, the 

denaturant batch must not exceed the sulfur content stated on the PTD. 

We continue to believe that annual reports from oxygenate producers are 

important enforcement and compliance assurance tool. Therefore, we are finalizing 

the requirement that producers and importers of DFE and other oxygenates must 

register with EPA as and oxygenate producer or importer and submit annual reports 

to EPA that include the total volume of DFE/oxygenate produced and an attestation 

that all batches met the proposed fuel quality requirements.

464

5. Additional Requirements for Denatured Fuel Ethanol, Ethanol 

Denaturants, and Other Gasoline Oxygenates 

We are finalizing regulatory text to clarify that DFE and other gasoline 

oxygenates must be composed solely of carbon, hydrogen, oxygen, nitrogen, and

sulfur. Manufacturers of denaturants that are designated as suitable for use in the 

manufacture of DFE that meets federal requirements will also be required to attest 

that the denaturant is composed solely of carbon, hydrogen, oxygen, nitrogen, and 

sulfur.

Producers and importers of gasoline oxygenates, producers and importers of 

denaturants designated as suitable for manufacturing DFE meeting federal sulfur 

 

464 Oxygenate producers and importers will be required to register with EPA as an oxygenate 

producer or importer by November 1, 2016, or 60 days before introducing certified denaturant into 

commerce, whichever is earlier. 
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requirements, fuel distributors, and oxygenate blenders will be required to maintain 

the applicable records for 5 years and provide them to EPA upon request. 

H. Standards for Fuel Used in Flexible Fueled Vehicles

Flexible fuel vehicles (FFVs) are vehicles that are capable of operating on 

both gasoline and gasoline blends containing up to 83 volume percent ethanol. 

Ethanol fuel blends that contain from 51 and 83 volume percent ethanol (E51-83) 

have historically been referred to as “E85” in reference to the maximum allowed 

content of denatured ethanol assuming a 2 percent denaturant concentration.465 

Fuel blends that contain from 16 to 50 percent ethanol (E16-50) are sometimes 

referred to as mid-level ethanol blends. Both E51-83 and E16-50 are currently used 

only in FFVs.

Whether FFVs are operating on clear gasoline (E0), E85, or any level of 

ethanol in between, to maintain emission performance the vehicles still need fuel 

that meets certain quality specifications, such as the 10 ppm average gasoline sulfur 

standard finalized today. We anticipate that the use of higher level ethanol blends 

in FFVs will continue to increase in the future as the RFS program continues to be 

implemented. Significant public and private initiatives are also currently underway 

to expand the use of ethanol blender pumps that dispense a variety of ethanol blends 

for use in FFVs.466 Therefore it is becoming increasingly important that all fuels 

used in FFVs, not just gasoline, meet fuel quality standards. The lack of separate 

fuel quality standards that apply to fuels used in FFVs could act to impede the 

further expansion of ethanol blended fuels, which is important to satisfying the 

requirements of the RFS program. For these reasons, we believe it is important that 

our gasoline quality standards for not just sulfur, but also benzene, Reid Vapor 

Pressure (RVP), detergency, and compliance with the interpretive rule defining the 

phrase “substantially similar” in CAA section 211(f)(1)467 (i.e., contain only carbon, 

hydrogen, oxygen, nitrogen, and sulfur) apply to any fuel used in an FFV.

Our various standards for gasoline currently apply to any fuel sold for use in 

motor vehicles, which is commonly or commercially known or sold as gasoline. In 

the fuel and fuel additive registration program, the gasoline family includes fuels 

composed of at least 50 percent clear gasoline by volume.468 As a result, our 

 

465 Industry consensus standards for E51-83 are described in ASTM International D5798-13, 

“Standard Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition 

Engines”.

466 The U.S. Department of Agriculture (USDA) has a program to assist in the funding for the 

installation of as many as 10,000 ethanol blender pumps over the next 15 years in rural areas. 

Growth Energy has a “Blend Your Own Ethanol” program to encourage the installation of ethanol 

blender pumps. 

467 73 FR 22277, 22281 (April 25, 2008).

468 40 CFR 79.56(e)(1)(i).
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gasoline standards currently apply to E16-50 ethanol blends. However, additional 

regulatory provisions could be useful to facilitate compliance assurance if we are to 

continue to treat such mid-level ethanol blends as gasoline. 

The existing requirement that E51-83 must be substantially similar (subsim) to the vehicle certification test fuel has provided a limited measure of control 

over in-use E51-83 fuel quality. The finalization of specifications for FFV exhaust 

emission test fuel in today’s action will provide improved clarity regarding what 

constitutes sub-sim for in-use E51-83. However, these specifications are not 

sufficient to provide clarity as to what is considered sub-sim for E51-83. For 

example, E51-83 manufactured using only gasoline, gasoline blendstocks for 

oxygenate blending (BOBs), a limited volume of butane that meets the standards for 

downstream blending into gasoline, and denatured fuel ethanol that meets the 

standards finalized today would clearly be sub-sim. However, use of natural 

gasoline may or may not result in an E51-83 blend that is sub-sim. In addition to 

the need for additional clarity regarding what constitutes sub-sim for E51-83, 

standards for sulfur, benzene, and RVP are needed to ensure fuel quality supports 

the attainment of our environmental goals.

At proposal, we sought comment on appropriate regulatory mechanisms to 

implement in-use quality standards for E51-83 and E16-50. We requested specific 

comment on possible approaches, including draft regulations, which were described 

in detail in a memorandum to the docket.

469 The draft regulations contained fuel 

quality specifications for E51-83 and two options that E51-83 manufacturers could 

use to demonstrate compliance. We sought comment on whether the Agency

should continue to treat E16-50 as gasoline and on the need to clarify existing 

regulations on the meaning of gasoline as any fuel that contains 50 percent or more 

gasoline. Given that E16-50 can only be used in FFVs, we also sought comment on 

whether to amend the regulations to treat E16-50 as an alternative fuel. If EPA 

were to treat E16-50 as an alternative fuel rather than gasoline, we sought comment 

on whether we should take the same approach for E16-50 as detailed in the draft 

regulations for E51-83 with respect to sulfur, benzene, RVP standards, and 

substantially similar requirements under CAA section 211(f). 

We received comments in support of and against our proposal. The vast 

majority of comments supported the need for EPA to promulgate in-use quality

standards for these higher level ethanol blends. We also received a number of 

detailed productive comments on the draft regulations. A number of stakeholders 

also expressed their willingness to work with EPA to provide supplementary 

information on issues that were not addressed at proposal and not contained in their 

 

469 Possible Approach to Fuel Quality Standards for Fuel Used in Flexible-Fuel Automotive SparkIgnition Vehicles (FFVs), Memorandum to the docket, Jeff Herzog, April 2013.
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comments. At this time, we acknowledge that additional work is needed on some 

issues and we note that such work could not be accommodated within the timeline 

for this Tier 3 final rule. Therefore, we are deferring final action on these 

provisions at this time. We will continue to work with stakeholders in developing 

in-use fuel quality standards for higher level ethanol blends following the 

publication of this final rule. Subsequently, we may issue a supplementary proposal 

prior to issuing a final rule if the additional information we receive from 

stakeholders warrants such an action.

I. Sulfur Standards for Purity Butane and Purity Pentane Streams Blended 

into Gasoline

Under the Tier 2 gasoline program, “purity” butane blended into gasoline 

downstream of the refinery is subject to a 30 ppm sulfur cap and other 

specifications regarding its composition.470 This is consistent with the 30 ppm 

refinery average sulfur standard under the Tier 2 program. Today’s action finalizes 

the proposed 10 ppm sulfur cap for purity butane blended into gasoline effective 

January 1, 2017. This is consistent with the Tier 3 10 ppm refinery average sulfur 

specification finalized today.

As discussed in Section VI.A.4 in today’s preamble, we are finalizing 

provisions to allow “purity” pentane to be blended into gasoline downstream of the 

refinery that are similar to the existing provisions for butane blending. This 

allowance will become effective [INSERT DATE 60 DAYS AFTER 

PUBLICATION IN THE FEDERAL REGISTER]. Until December 31, 2016, a 30 

ppm sulfur cap will apply to purity pentane blended into gasoline consistent with 

the existing sulfur cap for purity butane under the Tier 2 program.471 Beginning 

January 1, 2017, a 10 ppm sulfur cap will apply to purity pentane blended into 

gasoline consistent with the butane sulfur standard finalized today.

Butane blenders commented that a significant fraction of butane and pentane 

might be expected to have sulfur content in excess of 10 ppm after the Tier 3 

gasoline sulfur requirements become effective. To maintain a stable and adequate 

supply of butane and pentane for downstream RVP trimming, butane blenders 

requested that EPA adopt a 10 ppm sulfur average cap with a 30 ppm sulfur cap.472 

 

470 40 CFR 80.82.

471 Other requirements regarding the composition of purity pentane will also apply that are similar to 

those for purity butane.

472 RVP trimming refers to the practice of adding a limited amount of butane/pentane to previously 

certified gasoline at a terminal so that the finished gasoline is closer to the maximum applicable 

volatility standard (summer or winter) than can be attained at the refinery level.
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Butane and pentane have an inherently low sulfur content that can be made 

to meet a 10 ppm sulfur cap with relatively mild desulfurization techniques. We 

anticipate that butane and pentane suppliers will desulfurize these blendstocks to 

well below 10 ppm sulfur as part of their response to the Tier 3 gasoline sulfur 

requirements. Therefore, we believe that allowing butane and pentane used for 

RVP trimming to exceed a 10 ppm sulfur cap would needlessly complicate 

compliance assurance and defer some of benefits of the Tier 3 sulfur requirements.

J. Standards for CNG and LPG

The vehicle emissions standards finalized today are fuel neutral (i.e., they

are applicable regardless of the type of fuel that the vehicle is designed to use). 

There currently are no sulfur standards for the fuel used in compressed natural gas 

(CNG) and liquid propane gas (LPG) vehicles. We requested comment on whether 

it is necessary for EPA to establish sulfur standards for CNG and LPG to enable 

them meeting more stringent vehicle emissions standards, and whether a 15 ppm 

sulfur cap similar to that established for highway diesel fuel would be appropriate. 

Comment was also requested on whether and how to address the sulfur contribution 

from odorants and other additives used in CNG and LPG. 

We received comments in support of and against EPA establishing sulfur 

standards for CNG and LPG and whether such standards are necessary to enable 

CNG and LPG vehicles to meet the vehicle emissions standards finalized today.

473

 

In addition, some commenters stated that EPA should not establish new sulfur 

standards for in-use CNG and LPG fuels until additional data is available on current 

sulfur levels, and the feasibility/costs associated with potential additional sulfur 

controls have been evaluated. 

EPA is deferring finalizing in-use sulfur requirements for CNG/LPG in this 

final rule to provide additional time to work with stakeholders to collect data on 

current CNG/LPG sulfur content, to determine whether additional control of in-use 

CNG/LPG sulfur content is needed, and to evaluate the feasibility and costs 

associated with potential additional sulfur controls. Given that the information 

currently available suggests already low sulfur levels in CNG/LPG, the vehicle 

emissions standards finalized today will apply to CNG/LPG vehicles in addition to 

vehicles fueled on gasoline, diesel fuel, or any other fuel.474 

 

473 See Chapter 5.8. in the Summary and Analysis of Comments Document that accompanies this 

rule.

474 Several commenters provided information on CNG and LPG sulfur levels as discussed in the 

Summary and Analysis of Comments associated with this rule.
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K. Refinery Air Permitting Interactions

EPA recognized when it proposed the Tier 3 fuel program that it is 

important to the success of the Tier 3 fuel program that refineries be able to obtain 

air permits, if needed, in time to complete the modifications necessary to comply

with the proposed gasoline sulfur program. Accordingly, to help inform the public 

and obtain comment on this topic, a section of the preamble to the proposed rule 

presented background information on air permitting requirements and programs. 

That information is not repeated in full here. Based on our preliminary assessment 

of the proposed rule’s implications for needed refinery modifications, we estimated

at the time of our proposal that only a small percentage of refineries would likely

need to make modifications that would trigger a requirement to obtain air permits. 

Moreover, we anticipated that these permit applications would be processed quickly

enough that air permitting would not be a significant obstacle to timely compliance 

with the proposed gasoline sulfur program. We continue to anticipate that there 

will be no such obstacle.

Based on our final assessment, which takes into consideration updated 

information on current refinery configurations and operations and refineries’ future 

plans as well as the requirements and flexibilities in the final Tier 3 fuel program, 

we believe that under the final Tier 3 gasoline sulfur standard from a low of four to 

a high of nine refineries would need major source NSR permits, which includes 

nonattainment New Source Review (NSR) and/or Prevention of Significant 

Deterioration (PSD) permits. This estimate equates to approximately four to eight 

percent of the 108 refineries projected to sell gasoline that will be subject to the Tier 

3 standards. The number of refineries needing major source NSR permits could be 

even lower if refineries apply emission controls to reduce emissions increases 

below the significance levels applicable to affected pollutants or if they “net out” of 

NSR for the affected pollutants. As stated above, EPA continues to anticipate that 

permit applications associated with refinery changes needed to comply with the Tier 

3 fuel program will be processed quickly enough that air permitting will not be a 

significant obstacle to timely compliance with the gasoline sulfur program.

1. Proposal

In the proposed rule, we stated our anticipation that the types of changes

(both physical and operational) that would occur at most refineries would not result 

in sufficient emissions increases to require major NSR permits as a prerequisite for 

completing the needed changes for several reasons: because the emissions increase 

or the net emissions increase is naturally less than the significant level, because the 

refinery installs control technologies on project-affected units to further limit the 

emissions increase, and/or because the refinery “nets out” all or part of the 

emissions increase. 
Page 364 of 529

However, we anticipated that a small number of refineries had the potential 

to experience emissions increases to meet the proposed gasoline sulfur standard that 

are large enough to trigger major NSR (Nonattainment NSR and/or PSD). This 

small number of refineries would have to obtain a major NSR preconstruction 

permit prior to making these necessary process changes. For any required major 

NSR permits, the associated control technology requirements (BACT and/or 

LAER) would apply only to new or modified units associated with the project and 

not to units at the refinery that are not affected by the project. We did not anticipate 

that the time frames required for the small number of affected refineries to obtain 

any needed NSR and/or PSD permits would present an obstacle to timely 

compliance with the proposed Tier 3 gasoline sulfur requirements.

In the proposal we also discussed a number of concepts that might facilitate 

more expeditious permitting where it is required as a result of refinery changes 

needed to meet the new requirements. That discussion was based primarily on 

concepts that had arisen during the earlier Tier 2 fuel program. That discussion is 

not repeated here. We invited public comment on those concepts. 

2. Updated Assessment of Tier 3 Refinery Changes and Permitting 

Implications

EPA has updated our refinery-by-refinery assessment of the physical and 

operational changes that are likely to be needed to allow each active refinery in the 

U.S. to produce gasoline that complies with the final Tier 3 fuel specifications. We 

have also assessed the likely effects of those changes on refinery emissions. This 

updated assessment is described in more detail in the final RIA. Using this updated 

assessment, we were able to update our understanding of the potential scope of the 

major NSR permitting requirements refiners might face under the final Tier 3 

program. In general, our assessment indicates that only a small number of 

refineries will likely need to make modifications of a type and size that would 

trigger the need for a PSD or nonattainment NSR permit. 

In our updated analysis, we adjusted the analysis to reflect the existence of a 

nationwide average, banking, and trading (ABT) program and refined our estimates 

regarding the physical and operational changes that will be required at each refinery 

(as described in the final RIA). The modifications at a given refinery could include 

revamps to existing FCC pre- or post-treatment unit(s) or the installation of a new 

grassroots post-treatment unit for sulfur reduction. Based on the updated 

projections of refinery-specific changes, we re-estimated the increased demand for 

energy (i.e., fuel to generate process heat, steam, and electricity), hydrogen, and 

sulfur recovery associated with meeting the final Tier 3 standards. Having received 

no comments suggesting that they should be changed, we re-applied the

representative industry emission factors for NAAQS pollutants, their precursors, 

and GHGs for each emitting process and combined them with estimates of 
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incremental activity to estimate the emissions changes at each equipment unit (or 

group of similar units) at each refinery. 

We determined upper and lower bounds for emissions increases resulting 

from changes necessary to meet the final Tier 3 gasoline sulfur specification. We 

did not have sufficient detailed information to predict which refineries would find it 

most profitable to generate additional electrical power and hydrogen on site rather 

than purchasing these inputs from external suppliers. If a refinery generates these 

additional inputs internally on site, the additional emissions would count towards 

the significant emissions rates and could affect the need for a major NSR permit. 

To account for these variables, we evaluated a high and a low case for each 

identified scenario. Under the high case, we assumed 100 percent internal 

generation of the additional electrical power and hydrogen, and under the low case, 

100 percent external generation of the same. We expect refineries to actually be 

somewhere between these two extreme cases in the future. For the identified high 

and low cases, we compared the emissions increase for each pollutant at each 

refinery to the significant emissions increase threshold for that pollutant, taking into 

consideration the current attainment status for each pollutant where the refinery is 

located. 

An important aspect of our analysis is that we assumed that refineries would 

not install new emission controls on affected units for the purpose of staying below 

the significant emissions increase threshold and thereby not triggering major NSR. 

In particular, we did not assume that selective catalytic reduction (SCR) to control 

NOX emissions would be applied to new or modified fuel combustion units. This is 

an important assumption that tends to result in overestimates of the number of 

major NSR permits needed for NAAQS-related pollutants. In reality, applying new 

emission controls would be an option that refineries may employ to legally avoid 

major NSR permitting. We also did not assume that refineries would “net out” of 

NSR by taking credit for any emissions reductions occurring within a 

contemporaneous timeframe, including any new emissions reduction projects 

initiated specifically for the purpose of “netting out.” This analysis resulted in a 

prediction of whether a PSD and/or a Nonattainment NSR permit would be needed 

for each refinery and the pollutants that would have to be addressed in those 

permits, under each of the two scenarios. Only the results for the high case are 

presented here. More detailed results as well as the underlying methodology used 

in the permitting analysis are described in the final RIA for this rulemaking. In

general terms, we found that for the low case only about one-half the number of 

refineries were estimated to trigger major NSR as were estimated for the high case.

We found that under the high case, nine refineries appeared likely to have 

significant emissions increases for one or more pollutants and thus would trigger 
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major NSR.

475

 This estimate equates to approximately eight percent of the 108 

refineries projected to sell gasoline that will be subject to the Tier 3 standards. Of 

these nine refineries, we predicted that three refineries would need major source 

permits for NAAQS-related pollutants and their precursors (PSD and/or 

Nonattainment NSR) and for GHGs (results for GHG are discussed below). Thus, 

we believe that under the final Tier 3 program only about three refineries may need 

major NSR air permits to address NAAQS pollutants. This number could be lower 

if those refineries apply pollution controls, such as SCR for NOX, to sufficiently

reduce the emissions increases to levels that are below the applicable pollutant 

significance level, or if the refineries can achieve emissions reductions elsewhere at 

the facility to “net out” of major NSR. For refineries that are required to obtain a 

major NSR permit for NAAQS pollutants, the permitting process is expected to 

normally take about 9 to 12 months once the permitting authority has received a 

complete application.

All three refineries just described as potentially needing NSR permits for 

NAAQS pollutants are also projected to need PSD permits for GHGs. In addition 

to these three refineries, we estimated that six other refineries may require a PSD 

permit addressing only GHG emissions from new or modified equipment that is 

part of the project. For these nine refineries, BACT would have to be applied for 

GHG emissions, which we expect in most cases would mean that new or modified 

fuel-burning equipment would have to be designed for good energy efficiency. We 

expect that the types of equipment and process technologies that refiners are likely

to modify or add to meet the final Tier 3 standards will generally be sufficient to 

satisfy BACT requirements for GHG emissions in terms of achievability, costeffectiveness, and energy-efficiency even absent the requirement to obtain a permit, 

meaning that having to demonstrate that BACT is in place would not necessitate 

any shift in project design or cause increased costs. This expectation is based on 

the fact that there are strong economic incentives for refiners to design and purchase 

the most energy-efficient process equipment to minimize the cost of production. 

For example, some of the new or modified equipment expected to be involved in 

refinery projects designed to meet the final Tier 3 standards are fuel combustion 

units (e.g., process heaters). Because fuel cost (direct cost in the case of purchased 

natural gas and opportunity cost in the case of refinery-generated fuel gas) 

represents a significant component of total operating cost for such units, refineries 

will strive to maximize energy efficiency based on available technologies as part of 

their project design. 

 

475 Because state requirements regarding minor NSR permitting vary and we do not expect minor 

NSR permitting programs to be a significant challenge for refinery modification projects, we did not 

attempt to estimate how many of the remaining refineries might need to obtain minor NSR permits.
Page 367 of 529

In 2010, EPA issued a white paper on available and emerging technologies 

for reducing GHGs from the petroleum refining industry.

476

 This white paper 

addresses the types of equipment expected to be involved in projects designed to 

meet the final Tier 3 fuel standards, including process heaters/boilers, hydrogen 

plants, and sulfur recovery units. The identified GHG control technologies for 

these types of units predominately involve opportunities for energy efficiency. 

Consistent with the findings reported in the white paper, our experience to date with 

GHG permitting at refineries and other similar sources supports the application of 

energy efficient design and operation of affected units for meeting BACT

requirements, and we do not expect that in the time frame associated with Tier 3-

related projects, add-on controls would be required. 

For EPA-issued permits and permits issued by state or local agencies under 

delegation, consultation with other federal agencies under the Endangered Species 

Act and consideration of environmental justice will also be required. Significantly, 

no air quality modeling of GHGs will be required, and thus there would be no need 

to obtain extensive input information on meteorology and emissions from other 

nearby sources. Given these differences, we expect that the timeline for obtaining a 

permit only for GHG emissions should be shorter by several months than the 

timeline for a permit that addresses NAAQS pollutants.

On March 22, 2012, the President issued Executive Order 13604 (EO 

13604), Improving Performance of Federal Permitting and Review of Infrastructure 

Projects. EO 13604 states that federal permitting and review processes must provide 

a transparent, consistent, and predictable path for both project sponsors and affected 

communities, and that a number of described elements must be incorporated into 

routine agency practices to provide improvements in the performance of federal 

permitting processes. 

Under the EO, EPA has adopted a plan identifying the permitting and 

review processes that EPA views as most critical to significantly reduce the 

aggregate time required to make permitting and review decisions on infrastructure 

projects while improving outcomes for communities and the environment, and 

describing specific and measurable actions the agency will take to improve these 

processes.

477 With regard to permitting under the Clean Air Act, this plan stated 

EPA’s intention to issue a guidance memorandum by the end of 2012 to apply to 

PSD permits issued by EPA and by state or local agencies with delegated authority

from EPA, aimed at clarifying expectations and responsibilities regarding the timely

 

476 See “Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from the 

Petroleum Refining Industry,” October 2010, available at 

http://www.epa.gov/nsr/ghgpermitting.html.

477 The U.S. EPA Plan for Modernizing Federal Permitting and Review Pursuant to EO 13604, 

August 9, 2012. http://www.epa.gov/epainnov/pdf/eo-infrastructure-epa-final-plan.pdf
Page 368 of 529

processing of permit applications by an EPA Regional Office or delegated agency.

This memorandum was subsequently issued on October 15, 2012.478 EPA Regional 

Offices serving as the permitting authorities for refineries making modifications as 

part of the Tier 3 program will be guided by the memorandum. The memorandum 

also recommends that other permitting authorities consider following the 

approaches outlined in the memorandum where applicable.

3. Comments and Responses

Several oil industry commenters expressed doubt about whether EPA’s 

prediction of the small number of refineries that would need GHG permits was 

realistic. Commenters generally stated that permits for the modifications needed to 

comply with the Tier 3 requirements should be issued expeditiously. Some industry

commenters expressed doubt that this would be the case, noting what they

characterized as the slow pace at which GHG permits have been issued since the 

requirement for GHG permitting became effective. One oil industry commenter 

suggested that Tier 3-related modifications be completely exempt from permitting if 

they would not increase refinery capacity by more than 10 percent. No other 

specific suggestions for streamlining were submitted. Environmental groups 

commented that any efforts to streamline permitting should not relax the substantive 

requirements to get a permit. 

The final rule does not establish any new flexibilities or exceptions to 

current permitting regulations. On an ongoing basis, EPA continues to consider 

ways to streamline the permitting process consistent with CAA requirements and 

goals. EPA has concluded that only a small number of refineries appear to have the 

potential of triggering major source permitting as a result of modifications needed 

to meet the Tier 3 fuel program, given the flexibilities provided by the final 

program in terms of when modifications must be in place in order to achieve 

compliance. There were no industry comments that demonstrated a specific reason 

for concern about permitting implications on a broad scale. 

The Response to Comment Document includes a fuller summary of the 

comments on refinery permitting implications and the EPA responses to these 

comments.

L. Refinery Feasibility

While evaluating the merits of a national gasoline sulfur program to reduce 

emissions and enable future vehicle technologies, we also considered the refining 

 

478 Timely Processing of Prevention of Significant Deterioration (PSD) Permits when EPA or a PSDDelegated Air Agency Issues the Permit, Stephen D. Page to Regional Air Division Directors, 

October 15, 2012. http://www.epa.gov/region07/air/nsr/nsrmemos/timely.pdf
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industry’s ability to reduce sulfur to 10 ppm on average by January 1, 2017 and the 

associated costs (for more on fuel costs, refer to Section VII.B). Based on 

information gathered from numerous stakeholder meetings and discussions with 

vendor companies that provide the gasoline desulfurization technologies both 

before and after the proposal, as well as the results from our refinery-by-refinery

modeling, we believe it is technologically feasible at a reasonable cost for refiners 

to meet the sulfur standards in the lead time provided. A summary of our feasibility

analysis is presented below. For more on our feasibility and cost assessments and 

the refinery modeling that supports them, refer to Chapters 4 and 5 of the RIA. 

1. Comments Received

We received a number of comments on the proposed rule regarding 

feasibility and lead time. Commenters in the refining industry generally stated that 

they believe that the amount of lead time proposed is not sufficient. These 

commenters noted concerns that the short lead time proposed would drive up costs 

as there would be unscheduled shut-downs to install and/or revamp equipment to 

meet the Tier 3 sulfur standard, and would not provide enough time for the 

permitting process. These commenters requested at least five years of lead time, 

and noted that EPA has historically provided at least four years of lead time in 

previous fuels rulemakings. Commenters in the auto industry, as well as states and 

non-governmental organizations (NGOs), encouraged us to finalize the rule as soon 

as possible and to retain the January 1, 2017 start date to harmonize our program 

with California’s LEVIII program and to enable Tier 3 benefits as soon as possible. 

As discussed in more detail below, we believe the amount of lead time provided is 

sufficient, especially given the flexibilities being provided. A complete discussion 

on the comments received with regard to lead time can be found in Chapter 5 of the 

Summary and Analysis of Comments document.

2. Is it Feasible for Refiners to Comply with a 10 ppm Average Sulfur 

Standard?

Gasoline desulfurization technologies are well known and are readily

available. Many technologies were demonstrated under Tier 2 and have been 

further demonstrated by current fuel programs in California, Japan, and Europe. 

Under California’s Phase 3 Reformulated Gasoline program (CaRFG3), gasoline 

sulfur is limited to 15 ppm on average with a 20 ppm per-gallon cap.479 California 

reduced their per-gallon cap in phases from 60 ppm effective December 31, 2003, 

to 30 ppm effective December 31, 2005, to 20 ppm effective December 31, 2011. 

Actual in-use gasoline sulfur levels, however, have been largely constrained by the 

 

479 California Air Resources Board. (2008, August 29). The California Reformulated Gasoline 

Regulations, Title 13, California Code of Regulations, Sections 2250-2273.5. Retrieved from 

http://www.arb.ca.gov/fuels/gasoline/082908CaRFG_regs.pdf.
Page 370 of 529

Predictive Model that California refiners are using to demonstrate compliance. As a 

result, gasoline sulfur levels are lower than the CaRFG3 limits. Based on the 

Predictive Model, California gasoline contained approximately 10 ppm sulfur on 

average in 2010 (9 ppm in the summer and 11 ppm in the winter).

Japan currently has a 10 ppm gasoline sulfur cap that took effect in January 

2008. Europe also has a 10 ppm sulfur cap that has been adopted by the 30 

Member States that comprise the European Union (EU) and the European Free 

Trade Association (EFTA) as well as Albania and Bosnia-Herzegovina.480 Beijing, 

China also recently introduced a 10 ppm sulfur limit for gasoline.481 These 

standards are considerably more stringent than the 10 ppm annual average standard 

being finalized today because each batch of gasoline produced at every refinery

must meet the 10 ppm cap. As a result, every refinery must be designed to meet 

this cap regardless of changes in crude oil supply, operation conditions, or product 

mix. We note, however, that many oil refineries outside of the United States 

operate differently from their U.S. counterparts. U.S. refiners have invested more 

heavily in fluidized catalytic cracker (FCC) units than the rest of the world to 

maximize gasoline production. Because the FCC unit is responsible for nearly all 

the sulfur that ends up in gasoline, many U.S. refineries may face a bigger challenge 

in achieving 10 ppm gasoline sulfur levels. Even in the U.S., however, the picture 

is changing. The Annual Energy Outlook for 2013 produced by the Energy 

Information Administration supports the view that the U.S. demand for diesel fuel 

is increasing while the demand for gasoline is decreasing, starting the process that 

will make the U.S. more like Europe. Thus, U.S. refiners seem to be beginning to 

move away from relying on the FCC unit as the most important refinery unit. For 

this reason, the challenge of complying with more stringent gasoline sulfur control 

will decrease over time, and we discuss this more at the end of this section. 

The review of gasoline sulfur control in California and elsewhere and the 

future trend for gasoline demand support that achieving 10 ppm is feasible. The

Tier 3 requirements are less demanding than those of Europe or Japan. This is 

because the Tier 3 sulfur standard is an average standard instead of a cap standard. 

The accompanying Tier 3 cap standard is 80 ppm, which is much higher than the 

average standard, allows individual gasoline batches to vary in sulfur level 

throughout the year. Complying with Tier 3 is also made easier, as compared to 

California, Europe and Japan, by the ABT program which allows refineries with an 

easy path to compliance with Tier 3 to reduce their gasoline sulfur to less than 10 

ppm sulfur and generate and sell those credits to refineries, which are more 

challenged by Tier 3. 

 

480 Hart Energy Consulting. (2011). International Fuel Quality Center: 2011 Worldwide Fuel 

Specifications 

481 Article from China.org.cn entitled “Beijing to implement stricter fuel standards”, May 19, 2012, 

retrieved from http://www.china.org.cn/environment/2012-05/19/content_25422404.htm
Page 371 of 529

3. Can Refiners Meet the January 1, 2017 Start Date?

An adequate amount of lead time is required for the implementation of any

rulemaking. Depending on the level of effort required to comply, more or less lead 

time is also required. In the case of Tier 3, refiners need time to select the 

technology and the vendor that will provide the technology needed for compliance 

with the fuels standard. Next, they need time to arrange an engineering and 

construction (E & C) contractor which will design and oversee the construction of 

the refinery unit and the time needed to obtain the necessary permits and procure 

the necessary hardware. Next, refiners need time to construct the unit. Finally, the 

refiner needs time to make the necessary unit tie-ins of the unit with the rest of the 

refinery and then startup the unit. 

This section, along with detailed analysis provided in the RIA, explains that 

when taking into account the time to revamp existing FCC postreater units or build 

grassroots postreater units, tie-in the new or revamped units with the rest of the 

refinery and considering the flexibility offered by the ABT program, refiners will be 

able to comply with the Tier 3 program within the lead time provided. 

a. Time Required to Install Grassroots Units and Revamp Existing Units

The technologies for complying with Tier 3 are well known and well 

proven. Refiners which complied with Tier 2 using FCC naphtha desulfurization 

technologies installed the following units: Axens Prime G+, CDTech’s CDHydro 

and CDHDS, UOP’s ISAL Sinopec’s S-Zorb and Exxon’s Scanfining. Refiners 

shopped around and chose among these various technologies which were largely

untested at the time, which required us to provide more lead time for Tier 2. Since 

the Tier 2 sulfur standard began to be phased in, nine years have elapsed, and we 

believe that refiners now have direct experience with the installation and operation 

of these technologies and the vendor companies that license them and continue to 

support their installations onsite. We therefore believe that refiners will be able to 

reach a decision very quickly when complying with Tier 3, particularly, because in 

most cases the refiners will be revamping the units already installed for Tier 2 when 

complying with Tier 3. 

Based on our conversations with refiners, construction companies, vendor 

companies and from published literature, we estimated the time it takes to revamp 

existing postreaters and install grassroots postreaters. To revamp an existing 

postreater it is expected to require up to two years. Installing a grassroots postreater 

is estimated to require three years. Figure A reflects these project completion times 

showing the various major intermediate steps for completing the projects. 
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Figure V.L-1. Estimated Project Lead Time for Revamps and Grassroots 

Units

0- 3-

6

6-

9

9-

12

12-

15

15-

18

18-

21

21-

24

24-

27

27-

30

30-

33

33-

36

Revam

p

Pre- &

Postreaters

Scoping 

Studies

Process

Design

Permitting

Detailed 

Engineering

Field 

Construction

Start-up / 

Shakedown

Grassroots Postreater

Scoping 

Studies

Process

Design

Permitting

Detailed 

Engineering

Field 

Construction

Start-up / 

Shakedown

Since many of the Tier 3 revamps are expected to be very modest (e.g., 

change out a reboiler or heat exchanger), we believe that the revamping of 

postreaters could take less time than what we estimate in Figure V.L-1. Following 

EPA held discussions with many refiners in 2011 about EPA’s plan to pursue 

additional sulfur control post-Tier 2 (Tier 3), refiners began the process of assessing 

how they would comply. The Tier 3 proposal was delayed for about a year and it is 

our understanding from recent discussions with vendor companies and some 

refiners that, during this time, many refiners began assessing how they intended to 

comply with Tier 3. Thus, many refiners likely have completed the scoping studies, 

which involves technology selection, and in the case of grassroots units, vendor 

selection as well (refiners with a particular postreater technology in most cases are 

expected to simply revamp the same vendor’s technology, so there is no need to 

select a vendor). If refiners have already completed their scoping studies, we 

estimate that installation of the revamps or grassroots units would be about 3 

months shorter than the 2 and 3 years, respectively, than we estimate in Figure V.L1. 
Page 373 of 529

We believe that these project timelines are reasonable in light of past 

industry experiences which show FCC postreaters being installed in refineries in 

less time than what we estimate. At the Motiva refinery in Port Arthur, TX, a 

grassroots CDTech postreater was designed, constructed and started up in less than 

2 years. At two refineries in Germany, two Prime G+ units were designed, 

constructed and started up – one of them in two years, and the other in 18 months. 

As an extreme example, the $3.6 billion dollar, 180 kbbl/day crude oil expansion at 

Marathon’s Garyville, LA refinery was designed, constructed and started up in 4 

years. This project involved construction of 10 major refinery units. Since these 

may be best case examples, we continue to believe the projections provided above 

in Figure V.L-1 are reasonable. In contrast, EPA received comments and feedback 

during meetings from the refining industry suggesting that many of the steps 

outlined in Figure V.L-1 could take considerably longer. For example, they stated 

that permits could take 2 years and procurement of vessels, pumps, compressors 

and heaters could take 2 years as well, extending the time needed to complete their 

projects. However, even if this may be true in some situations, the examples above 

highlight that this is not true in all situations. Furthermore, most refineries, as 

discussed in section V.K. will not need to go through any extensive permitting 

process and as discussed below, not all refineries will need to undertake extensive 

revamps of existing units or installation of grassroots units. So once again, we 

believe the timeline shown is reasonable for the vast majority of refineries. Many

can complete there actions faster. For those that may require a longer timeline, the 

program flexibilities discussed below allow for this within the lead time provided. 

b. Program Flexibility that Extends Lead Time

As discussed in Section V.D, the final Tier 3 program includes an ABT 

program that significantly helps refiners comply with the January 1, 2017 start date. 

There are several provisions of the ABT program that help with respect to any

leadtime constraints. 

The ABT program allows for ongoing intra-company and inter-company 

trading nationwide. This will allow some refineries to over-comply with the 10 

ppm gasoline sulfur standard (in our analysis, we modeled these refineries bringing 

their gasoline down to 5 ppm), allowing other refineries that would otherwise need 

to install grassroots units to not invest and purchase credits instead. This aspect of 

the ABT program is very important because our analysis estimates that only one 

refinery would need to install a grassroots hydrotreater whereas without the ABT 

provisions, there could be as many as 20 grassroots units. This one aspect has huge 

implications for leadtime because as discussed in the previous subsection, revamps 

require two years or less whereas grassroots FCC postreater units require 

approximately three years to install. We are convinced that this aspect of the ABT 

program will be utilized to the maximum extent possible because refineries 

revamping their postreaters in lieu of installing grassroots posttreaters results in the 

most cost-effective mechanism for meeting the 10 ppm annual average standard. 
Page 374 of 529

An important issue to consider is that in order for refiners to opt not to 

invest in a grassroots unit they would have to trust that credits will be available to 

them. For the proposal, we conservatively assumed that refiners would only rely on 

credits if they could generate them internally. However, for the final rule analysis, 

we have assessed how the sulfur credits were being traded under Tier 2 and found 

that over half the sulfur credits were freely traded between companies (as opposed 

to only being used within companies), and many single-refinery companies had 

sulfur levels above 30 ppm (single-refinery companies must purchase credits from 

other companies). Because credits have a 5-year life, we also see in the Tier 2 data 

that refiners tend to sell credits rather than let them simply expire. Refiners may

hold them as a contingency, but then sell them prior to their expiration. For 

example, in 2012, 40 percent of the credits traded were generated in 2007 and were 

set to expire at the end of 2012. This one quality of the Tier 2 program ensures the 

free access to credits. We designed the Tier 3 credit trading program to work just 

like the Tier 2 credit trading program, thus we are confident that there will be 

widespread trading within and between refining companies. 

A second aspect of the ABT program that helps with leadtime is the 

provision for generating early sulfur credits and banking them for later use. As 

discussed in Section V.D above, this provision allows refineries to reduce their 

gasoline sulfur to less than 30 ppm prior to January 1, 2017 and bank the credits for 

later use. Based on comments that we received on the proposed rule, we are 

allowing Tier 2 credits which are generated during the years 2012 and 2013 to also 

be used to show compliance for Tier 3. This effectively extends the early credit 

generation period for Tier 3 to encompass the years 2012 to 2016, which is 5 years. 

Analyzing the 2012 gasoline quality data that refiners reported to EPA, we found 

that gasoline sulfur levels in the U.S. averaged about 26.7 ppm. Thus, refiners have 

already begun overcomplying with Tier 2 by 3.3 ppm, and are therefore already 

generating early credits that can be used for Tier 3. If refiners do nothing more but 

continue to overcomply with Tier 2 by 3.3 ppm over the 5 years of early credit 

generation, refiners will have generated enough credits to delay the completion of 

their capital projects by roughly a year. Furthermore since those credits generated 

in 2012 and 2013 will expire in 2017 and 2018 respectively, refiners will have an 

incentive to either use them themselves or trade them in 2017 and 2018. Thus 

refiners that may need to count on them to delay their capital investment are likely

to be able to have access to them. 

When the extent of the flexibility afforded by the final ABT provisions is 

fully understood by refiners, we believe that refiners will generate a lot more early 

credits with their existing gasoline sulfur control units than the 3.3 ppm we 

observed in 2012. As we discussed in our cost analysis, to produce more diesel fuel 

in response to a greater demand for diesel fuel relative to gasoline, refiners are 
Page 375 of 529

undercutting the swingcut portion of FCC naphtha at their refineries.482 This action 

to shift what historically was blended into the gasoline pool to the diesel fuel pool, 

actually also dramatically reduces the sulfur content of the gasoline pool. If the 

entire swingcut portion of FCC naphtha is undercut to the diesel fuel pool, the 

amount of sulfur in the gasoline pool is reduced by about 50 percent. Our cost 

analysis estimates that at almost one quarter of U.S. refineries, refiners are fully

undercutting the FCC naphtha to diesel fuel today. At many other refineries, 

refiners are only partially undercutting their FCC naphtha. These refineries will be 

able to reduce the sulfur of their gasoline well below their current levels and 

generate a large number of early credits for Tier 3. Even for the subset of refineries 

at which the FCC naphtha is not being undercut, refiners can assess how much 

activity or catalyst life is left in its FCC postreater catalyst and compare this time 

with the time to the next turnaround when the FCC postreater catalyst is scheduled 

to be replaced. If there is spare catalyst life, the refiner could elect to “turn up” 

their postreaters to reduce their gasoline sulfur levels to under 30 ppm. With this 

strategy, the refiner would generate early sulfur credits. Also, when the refiner 

replaces the catalyst in its Tier 2 postreater, it can elect to do so with a more active 

catalyst which would allow the refinery to produce gasoline at sulfur levels below 

30 ppm and generate more early credits for Tier 3. 

Based on the early actions refiners are already taking, or could take, to 

reduce their gasoline sulfur levels, we believe that refiners would be able to reduce 

their gasoline sulfur to as low as 20 ppm, on average. By averaging 20 ppm for 2.5 

years prior to 2017, refiners would be able to delay completion of all capital 

investments for Tier 3 until mid 2019. If we add the 3.3 ppm of credits during 

2012, 2013 and first part of 2014, refiners would be able to delay completion of all 

capital investments in Tier 3 until 2020. Thus, the early credit provisions will, ineffect, provide nearly 6 years of leadtime for full compliance with the fuels 

program. This will allow ample time for refiners to complete their investment and 

schedule their tie-ins during normal shutdown activities. It effectively provides 

even more lead time than the 5 years that the refining industry requested in their 

comments. The delay in the program implementation will also help to distribute the 

demand on the E & C industry over more years ensuring that the E & C industry

won’t be overwhelmed. 

We are also finalizing a compliance deadline of January 1, 2020 for small 

refiners and small volume refineries (i.e., refineries processing less than or equal to 

75,000 net barrels per day of crude oil). This will provide approximately 36 of the 

108 affected refineries with nearly 6 years of lead time; again more than the 5 years 

 

482 The term swingcut means that this portion of the FCC product pool can be blended into gasoline 

or diesel fuel while still meeting the fuel quality specifications for either fuel regardless of where this 

swingcut is blended. 
Page 376 of 529

that the refining industry requested in their comments. We believe that these 

refiners and refineries are disproportionally impacted when it comes to their cost of 

compliance and ability to rationalize investment costs in today’s gasoline market. 

Giving these refiners and refineries additional lead time provides more time to 

invest in desulfurization technology, take advantage of advancements in 

technology, develop confidence in a Tier 3 credit market as a means of compliance, 

and avoid competition for capital, engineering, and construction resources with the 

larger refineries. Due to the January 1, 2020 compliance deadline for small refiners 

and small volume refineries we estimate that of the 64 refineries that will ultimately

need to revamp (63) their existing hydrotreaters or add a grassroots hydrotreater (1) 

over the course of implementing the Tier 3 program 15 refineries could wait to take 

such actions until 2020. Further, as discussed in more detail in Section V.E.1, small 

refiners and small volume refineries can generate early credits (from January 1, 

2017 through December 31, 2019) relative to 30 ppm for sale to other small 

refiners/small volume refineries, and relative to 10 ppm for sale to non-small 

refiners. This could provide another pool of early credits for Tier 3 prior to January

1, 2017 and ongoing credits during the years of 2017, 2018 and 2019.

Despite the flexibility afforded by the ABT program, some refiners have 

expressed concern that should they want or need to rely on credits for compliance, 

they may not be able to do so if they cannot be assured that they will be able to 

acquire the necessary credits from other parties when the time comes. This could 

force them into making relatively costly investments that they would otherwise be 

able to avoid. We recognize that this may be a concern, particularly prior to 2020 

when the market will be in a state of transition. While we cannot guarantee credit 

availability, and we are confident that the program as designed provides ample 

opportunity for credit generation, we do believe that providing the market with at 

least some basic information on credit availability may provide some added 

assurance and aid in credit market liquidity. Consequently, we pledge to work with 

the refining industry on ways to make information on the sulfur credit market more 

transparent over the period leading up to 2020, balancing their need for information 

with the resource constraints of the Agency. In doing so, to protect confidentiality, 

we will not be able to identify individual company credit balances or deficits. 

Because industry has already shown the ability to identify and establish the 

necessary trading relationships under the Tier 2 program, we anticipate that they

will be able to continue to do so under Tier 3. 

In summary, we believe that the ABT program we are finalizing today

provides ample flexibility for complying with Tier 3. The averaging provisions will 

allow refiners that only need to revamp their Tier 2 postreaters to generate credits 

by overcomplying with the 10 ppm standard, and in turn allow refineries that 

otherwise need to install grassroots units to comply solely through the purchase of 

credits. The banking provisions also allow refiners to generate early credits, 

effectively delaying investments for compliance to potentially as late as 2020. 

Finally, the small refiner and small refinery provisions delay compliance for 
Page 377 of 529

approximately 36 refineries until 2020, as well as generate and trade early credits. 

We believe that all of these provisions effectively address any leadtime concerns. 

Furthermore, there are additional options available to refineries to avoid a 

noncompliance situation should all these program flexibilities prove insufficient. 

Refineries are permitted to carry a credit deficit for one year as long as they make it 

up the following year, and the final rule allows refiners to apply for hardship 

waivers if necessary. In addition, refineries with access to export markets can 

always choose to export fuel until such time as they can bring their desulfurization 

capacity online. There is a large and growing gasoline export market from the U.S. 

already. Such exports of higher sulfur gasoline could be offset through imports of 

compliant gasoline such as historically occurred from Europe, which has a 10 ppm 

sulfur cap on gasoline. 

c. Impact of Turnaround Timing

We received numerous comments on the proposed January 1, 2017 

compliance deadline. In their comments to the proposed Tier 3 rulemaking, the oil 

industry stated that EPA must consider and include the time it takes to tie-in the 

revamps and grassroots units in the proposed leadtime. The oil industry urged EPA 

increase the leadtime for Tier 3 to 5 years to allow for refiners to make their 

investments needed to comply with Tier 3 and tie-in those new investments. In

today’s action we are finalizing a compliance deadline of January 1, 2017. As 

previously explained above, various provisions of the ABT program effectively

provide nearly 6 years of leadtime to complete capital projects. We also note that 

the capital projects do not have to be completed prior to installing the necessary tieins. We do agree, however, that the need to make tie-ins must be considered when 

assessing the feasibility of leadtime, and in doing so, our analysis shows that 

refiners can comply with Tier 3 within the leadtime provided. This is true not only

because the final rule effectively provides nearly 6 years of leadtime to complete 

capital projects, as described above, but also because the capital projects do not 

have to be completed prior to installing the necessary tie-ins.

When a refiner builds a grassroots unit or some sort of revamp which 

involves new reactor volume or perhaps by adding a splitter, this new capital must 

be “tied-in” to the rest of the refinery. The tie in usually involves connecting a pipe 

from the existing unit to the new capital installed for complying with Tier 3. 

However, a pipe cannot simply be added while the refinery is operating. Instead, 

the refiner will add the necessary pipe for making the tie-in when the refinery is 

shutdown for regular maintenance. The revamp or grassroots unit does not have to 

be started up at that time. Instead, the connection pipe just needs to be added and 

blocked off with a sealing-type valve and a blind flange (essentially a flat piece of 

steel) is bolted on as a precaution against a leaky valve. Once this piping has been 

added, the refiner can restart its refinery. Then when the refiner is ready to 

complete the tie-in to the completed Tier 3 revamp or grassroots unit, the refiner 

would remove the blind flange and connect a pipe which connects the existing part 
Page 378 of 529

of the refinery to the newly installed grassroots postreater unit or revamp postreater 

subunit. This last step can either occur when the refinery is shutdown or still 

operating. At that point the refiner would only need to open the block valve to 

complete the tie-in of the grassroots unit or revamp to the existing refinery. 

On its webpage, the American Petroleum Institute (API) reports that the 

average time between turnarounds is 4 years when the U.S. refineries perform 

maintenance on the FCC unit.483 This means that on average, 25% of U.S. 

refineries shutdown to perform maintenance on its FCC units each year. Most 

often, refiners conduct maintenance turnarounds on their refineries during the 

spring when the demand for gasoline and diesel fuel is at their lowest. Thus, 

refiners will have the years of 2014, 2015 and 2016 to make their tie-ins during a 

regularly scheduled refinery turnaround to be able to comply by January 1, 2017, 

thus roughly three-quarters of the tie-ins could occur before the January 1, 2017 

compliance date.484 If we superimpose the tie-in issue with the types of investments 

we project will be made for Tier 3, we project that for three-quarters of the 

revamps, refiners will be able to make their tie-ins prior to the January 1, 2017 start 

date, while the other refineries will require until the spring of 2017 to make their 

tie-ins. As a worse-case scenario, if refiners don’t even try to begin making their 

tie-ins until the spring of 2015, they would need the spring of 2015 to the spring of 

2018 to complete their tie-ins. 

However, regardless of whether we assume that tie-ins begin to occur in 

2014 or 2015, the flexibility afforded by the ABT program will readily enable

refiners to complete their capital investments and tie-ins and comply with Tier 3 

within the lead time provided. A more detailed discussion and analysis of Tier 3 

compliance considering unit construction time, the tie-ins of revamps and grassroots 

units and availability of credits is contained in Chapter 4 of the RIA.

d. Hardship

While we project that there will be plenty of credits available to allow 

refiners to complete their capital investments and tie in the new or revamped unit to 

the rest of their refinery, we are providing another option to refiners as a safety

valve in case there is a shortfall of credits. Consistent with our proposal, today’s 

 

483 Fact Sheet entitled “Refinery Turnarounds,” American Petroleum Institute (API) webpage: 

http://www.api.org/oil-and-natural-gas-overview/fuels-and-refining/refineries/refinery-turnarounds; 

downloaded June 21, 2013.

484 Since most refiners have already completed their scoping studies with the vendor companies 

which license the desulfurization technologies, they likely already understand what steps would need 

to be taken to tie-in their revamps and grassroots units with their existing refinery. For this reason, 

we believe that refiners can begin making their tie-ins as soon as the spring of 2014, and perhaps 

even earlier than that. One refiner who owns a number of refineries shared with us that they 

prepared the tie-ins for Tier 3 when they installed their Tier 2 units. 
Page 379 of 529

rule contains provisions for a refiner to apply for a hardship waiver. Thus, where a 

refiner cannot complete its project by January 1, 2017 and credits are not available 

or are prohibitively expensive, the refiner may file a hardship waiver. Details of 

our hardship provisions can be found in Section V.E.2. 

e. Impact on the Engineering and Construction Industry

As in prior rules, we also evaluated the capability of E&C industries to 

design and build gasoline hydrotreaters as well as performing routine maintenance. 

Two areas where it is important to consider the impact of the fuel sulfur standards 

are: (1) refiners’ ability to procure design and construction services, and (2) 

refiners’ ability to obtain the capital necessary for the construction of new 

equipment required to meet the new gasoline quality specification. We evaluated 

the requirement for engineering design and construction personnel in a manner 

consistent with the Tier 2 analysis, particularly for three types of workers needed to 

implement the refinery changes: front-end designers, detailed designers, and 

construction workers. We developed estimates of the maximum number of each of 

these types of workers needed throughout the design and construction process and 

compared those figures to the number of personnel currently employed in these 

areas. 

The number of job hours necessary to design and build individual pieces of 

refinery equipment and the job hours per piece of equipment were taken from 

Moncrief and Ragsdale.485 Their paper summarizes analyses performed in support 

of a National Petroleum Council study of gasoline desulfurization, as well as other 

potential fuel quality changes. The design and construction factors for 

desulfurization equipment are summarized in Table V-1.

Table V-1 Design and Construction Factors

Gasoline Refiners

Number of New Pieces of Equipment per Refinery 60

Number of Revamped Pieces of Equipment per Refinery 15

Job Hours Per Piece of New Equipmenta

Front End Design 300

 

485 Moncrief, Philip & Ragsdale, Ralph. (2000). Can the U.S. E&C Industry Meet the EPA’s Low 

Sulfur Timetable? Paper presented at NPRA Annual Meeting, March 26-28, 2000. Paper No. AM00-57.
Page 380 of 529

Detailed Design 1,200

Direct and Indirect Construction 9,150

a Revamped equipment estimated to require half as many hours per piece of equipment

Refinery projects will differ in complexity and scope. Even if all refiners 

desired to complete their project by the same date, their projects would inevitably 

begin over a range of months. Thus, two projects scheduled to start up at exactly

the same time are not likely to proceed through each step of the design and 

construction process at the same time. Second, the design and construction 

industries will likely provide refiners with economic incentives to avoid temporary

peaks in the demand for personnel. 

Applying the above factors, we projected the maximum number of 

personnel needed in any given month for each type of job. The results are shown in

Table V-2. In addition to total personnel required, the percentage of the U.S. 

workforce in these areas is also shown, assuming that half of all projects occur in 

the Gulf Coast. 

Table V-2 Maximum Monthly Demand for Personnel

Front-End 

Design

Detailed 

Engineering

Construction

Tier 3 Gasoline Sulfur Program

Number of Workers 202 809 6,012

Percentage of Current Workforcea11% 9% 4%

a Based on current employment in the U.S. Gulf Coast assuming half of all projects occur in the Gulf 

Coast

To meet the Tier 3 sulfur standards, refiners are expected to invest $2.0 

billion between 2014 and 2019 and utilize approximately 250 front-end design and 

engineering jobs and 1,500 construction jobs. The number of estimated jobs 

required is small relative to overall number available in the U.S. job market. As 

such, we believe that three years, plus the additional flexibilities provided, is 

adequate lead time for refineries to obtain necessary permits, secure E&C resources, 

install new desulfurization equipment, and make all necessary retrofits to meet the 

Tier 3 sulfur standards. For an in-depth assessment of stationary source 

implications, refer to Section V.K. For more on our E&C assessment, refer to 

Chapter 4 of the RIA.
Page 381 of 529

M. Statutory Authority for Tier 3 Fuel Controls

Consistent with our proposal, we are adopting gasoline sulfur controls under 

our authority in section 211(c)(1) of the Clean Air Act. This section gives us the 

authority to “control or prohibit the manufacture, introduction into commerce, 

offering for sale, or sale” of any fuel or fuel additive for use in a motor vehicle, 

motor vehicle engine, or nonroad engine or nonroad vehicle (1) whose emission 

products, in the judgment of the Administrator, cause or contribute to air pollution 

which may reasonably be anticipated to endanger the public health or welfare 

[section 211(c)(1)(A)] or (2) whose emission products will impair to a significant 

degree the performance of any emission control device or system which is in 

general use, or which the Administrator finds has been developed to a point where 

in a reasonable time it would be in general use were the fuel control or prohibition 

adopted [section 211(c)(1)(B)]. Consistent with our proposal, we are finalizing 

controls on gasoline sulfur levels based on both of the Clean Air Act criteria, as 

described in more detail below.

1. Section 211(c)(1)(A)

Under the first criterion, we believe that emission products of gasoline with 

current levels of sulfur contribute to ambient levels of ozone, particulate matter 

(PM), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO), 

which are all pollutants for which EPA has established National Ambient Air 

Quality Standards (NAAQS). These pollutants are linked with respiratory and/or 

cardiovascular problems and other adverse health impacts leading to increased 

medication use, hospital admissions, emergency department visits, and premature 

mortality. Approximately 149 million people currently live in counties exceeding a 

NAAQS.486 Motor vehicles also emit air toxics, and the majority of Americans 

continue to be exposed to ambient concentrations of air toxics at levels which have 

the potential to cause adverse health effects, including cancer, immune system 

damage, and neurological, reproductive, developmental, respiratory, and other 

health problems.487 A more detailed discussion of the health and environmental 

effects of these pollutants is included in Section II.B. As discussed there, emissions 

of these pollutants cause or contribute to ambient levels of air pollution that are 

reasonably anticipated to endanger public health and welfare. Control of gasoline 

sulfur to 10 ppm will lead to significant reductions in emissions of these pollutants, 

with the benefits to public health and welfare significantly outweighing the costs. 

 

486 Data come from Summary Nonattainment Area Population Exposure Report, current as of July 

20, 2012 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQOAR-2011-0135.

487 U.S. EPA. (2011) Summary of Results for the 2005 National-Scale Assessment. 

www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
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EPA has evaluated the technical feasibility of achieving these sulfur levels, 

including the cost of the reductions. We have concluded that these reductions are 

feasible in the lead time provided. For more on the feasibility of the fuel standards, 

refer to Section V.L above and Chapter 4 of the RIA.

As discussed in Section III, and further supported by the discussion in 

Section IV.A.6, EPA also evaluated the emissions reductions from pre-Tier 3 

vehicles that will be achieved by controlling gasoline sulfur level to 10 ppm on 

average. The 10 ppm sulfur standard will provide significant reductions in harmful 

emissions independent of the vehicle standards and these reductions are significant 

and contribute to the total monetized health benefits. Already in 2018, when the 

emission reductions are almost entirely due to the sulfur standards, the Tier 3 

program will provide significant benefits. We continue to believe that the Tier 3

program will produce benefits to public health and welfare whose value 

significantly outweighs the costs. These reductions can be achieved in a manner 

that is technologically feasible. In sum, EPA concludes that the entire body of 

evidence strongly supports the view that controlling gasoline sulfur to 10 ppm is 

quite reasonable in light of the emissions reductions and benefits achieved, taking 

costs into consideration. For more detail on the costs and benefits of the Tier 3 

program, refer to Chapter 5 of the RIA. 

Section 211(c)(2)(A) requires that, prior to adopting a fuel control based on 

a finding that the fuel’s emission products contribute to air pollution that can 

reasonably be anticipated to endanger public health or welfare, EPA must consider 

“all relevant medical and scientific evidence available, including consideration of 

other technologically or economically feasible means of achieving emission 

standards under [section 202 of the Act].” EPA’s analysis of the medical and 

scientific evidence relating to the emissions impact from motor vehicle engines, 

which are impacted by gasoline sulfur, is described in more detail in Chapter 6 of

the RIA. EPA has also satisfied the statutory requirement to consider “other 

technologically or economically feasible means of achieving emission standards 

under section [202 of the Act].” This provision has been interpreted as requiring 

consideration of establishing emission standards under section 202 prior to 

establishing controls or prohibitions on fuels or fuel additives under section 

211(c)(1)(A). See Ethyl	Corp.	v.	EPA, 541 F.2d. 1, 31-32 (D.C. Cir. 1976). In 

Ethyl, the court stated that section 211(c)(2)(A) calls for good faith consideration of 

the evidence and options, not for mandatory deference to regulation under section 

202 compared to fuel controls. Id. at 32, n.66. EPA is also adopting Tier 3 

emissions standards for motor vehicles under section 202. These standards could 

not achieve any emission reductions for vehicles already in use, while reducing fuel 

sulfur will achieve large emission reductions for vehicles already in use. For new 

vehicles, the use of 10 ppm average sulfur fuel is an essential part of achieving Tier 

3 levels while applying an array of advancements in emissions control technology

to the light-duty fleet. As shown in Section IV.A, we believe that achieving the 

Tier 3 exhaust emission standards will require technological improvements such as 
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very careful control of the exhaust chemistry and exhaust temperatures to ensure 

high catalyst efficiency. These technology improvements, which are described in 

greater detail in the RIA (Chapter 1) – improving warm-up and catalyst light-off 

after cold starts and maintaining very high catalyst efficiency – all rely on 10 ppm 

sulfur average fuel to achieve the very significant emissions reductions required for 

the fleet to achieve Tier 3 emissions levels.

Achieving Tier 3 emissions standards without a reduction in sulfur to 10 

ppm levels would only be possible if there were technology improvements 

significantly above and beyond even those mentioned above. EPA cannot identify

technology improvements that could provide such a large additional increase in 

emissions control effectiveness, across the fleet, above and beyond that provided by

the major improvements in technology discussed above, without any additional 

gasoline sulfur control. As discussed in Section IV.A.3, the Tier 3 fleet average 

exhaust emissions standards of 30 mg/mi NMOG+NOx will require large 

reductions of emissions across a broad range of light-duty vehicles and trucks with 

differing degrees of utility. Specifically, achieving Tier 3 emissions standards as an 

average across the fleet will require fleet wide reductions of approximately 80%. 

We believe this means significant reductions from all sectors, with the result that 

there is a need for major reductions from all types of vehicles in the light-duty fleet, 

including those above as well as most vehicles that are already near, at, or below the 

Tier 3 Bin 30 fleet average standard.

Achieving these reductions presents a major technology challenge and EPA 

is not aware of technology improvements that could provide such large additional 

increases in emissions control effectiveness, across the fleet, above and beyond that 

provided by the major improvements in control technologies expected for use in 

meeting today’s Tier 3 standards. Rather, as available test data indicates, in 

addition to lower gasoline sulfur levels, the required reductions are of a magnitude 

that EPA expects manufacturers to employ advances in technology in all of the 

relevant areas of emissions control – exhaust catalyst technologies, (such as 

reducing the time to catalyst light off, improving exhaust catalyst durability at 

120,000 or 150,000 miles and improving efficiency of fully warmed up exhaust 

catalysts), reducing engine out emissions, power train calibration primarily focused 

on reducing cold-start NMOG emissions, and on reducing both cold-start and 

warmed-up (running) NOX emissions.

The impact of sulfur reduction on the effectiveness of the available 

technology improvements plays such a large role in achieving the Tier 3 emissions 

standards that it is clearly unrealistic to expect that technology would be available, 

at the 30 ppm sulfur standard, to fill the emission control gap left from no sulfur 

reduction, and still achieve the very significant fleet wide reductions needed to meet 

the Tier 3 fleet average. In effect reducing sulfur from 30 ppm to 10 ppm has such 

a large impact on the ability of the technology improvements to achieve Tier 3 

emissions levels that absent these sulfur reductions there is not a suite of technology
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advancements available to fill the resulting gap in emissions reductions. As also 

discussed in Section IV.A.6, testing of Tier 2 and Tier 3 type vehicles, as well as 

other information, shows that sulfur has a very large impact on the effectiveness of 

the control technologies expected to be used in Tier 3 vehicles. Without the 

reduction in sulfur to a 10 ppm average, the major technology improvements 

projected under Tier 3 would only result in a limited portion of the emissions 

reductions needed to achieve Tier 3 levels. For example, without the reduction in 

sulfur from a 30 ppm to 10 ppm average, the technology improvements would not 

come close to achieving Tier 3 levels. In some cases this may result in the same

effectiveness as the current Tier 2 technology and achieve only approximately Tier 

2 levels of exhaust emissions control. 

As earlier explained, EPA has not identified technology that would achieve 

the average Tier 3 emissions standards, across the fleet, with sulfur at 30 ppm 

levels, and as a result Tier 3 emissions standards would not be technically feasible 

and achievable. This is also the case for levels in-between 30 and 10 ppm, e.g., 20 

ppm. The required emissions reductions are so large and widespread across the 

fleet, and the technology challenges are high enough, especially for heavier 

vehicles, that the large increase in emissions that would occur even from a higher

average sulfur level compared to 10 ppm average would lead to an inability for the 

technology to widely achieve the Tier 3 fleet wide average emissions standards. 

Further, as also explained in Section IV.A.6, larger vehicles (the largest 

LDVs and LDT3s, LDT4s and MDPVs) will have greater difficulty achieving coldstart NMOG emissions control as a result of today’s emissions standards. 

(Certifying to a useful life of 150,000 miles versus the current 120,000 miles will 

further add to manufacturers’ compliance challenge for large light trucks; see 

Section IV.A.7.c for the useful life requirements.) This is based in part on the 

impact on NMOG emissions of the larger engine surface-to-volume ratio and 

resultant heat conduction from the combustion chamber during warm-up. There are 

also tradeoffs between some cold-start NMOG controls and cold-start NOx control. 

For example, secondary air injection and/or leaner fueling strategies improve 

catalyst light-off for NMOG after a cold-start but also place OSC components in an 

oxidation state that limits potential for NOx reduction and thus often result in higher 

cold-start NOx emissions. Some applications achieve lower NMOG+NOx 

emissions without the use of secondary air injection by careful calibration, changes 

to the catalyst formulation and balancing of catalyst HC and NOx activity. The 

EPA Prototype Silverado and the developmental Ford Explorer discussed in Section 

IV.A.6.c are specific examples of this approach. Thus, as a result of today’s 

emissions standards these larger vehicles, in addition to needing to reduce NOx 

emissions to near-zero levels (as is generally the case for all Tier 3 vehicles, as 

discussed below), these trucks may also have additional NMOG reduction 

challenge. 
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2. Section 211(c)(1)(B)

Under the second criterion, we believe that sulfur in gasoline will 

significantly impair the emission-control systems expected to be in general use in 

motor vehicle engines designed to meet the Tier 3 emission standards. The Tier 3 

fuel sulfur standards will restrict gasoline sulfur content to an annual average of 10 

ppm beginning in 2017, to enable compliance with new emission standards based 

on the use of advanced emission control technology that will be available to Tier 3 

vehicles.

Section IV describes the substantial adverse effect of high gasoline sulfur 

levels on the emission-control devices or systems for vehicles and engines meeting 

the Tier 3 emission standards. As discussed in Section IV.A.6, sulfur in gasoline 

inhibits the emissions control performance of modern three-way exhaust catalyst 

systems by selectively binding with, and in some instances reacting with active sites 

and coating materials. The amount of sulfur retained by the catalyst is primarily a 

function of its operating temperature, the active materials and coatings used within 

the catalyst, the concentration of sulfur oxides in the incoming exhaust gases, and 

air-to-fuel ratio feedback and control by the engine management system. In addition 

to its interaction with catalyst materials, sulfur can also react with the wash-coating 

itself to form alumina sulfate, which in turn can block coating pores and reduce

gaseous diffusion to active materials below the coating surface. Sulfur also 

interferes with the ability of OSC components to reduce NOX emissions. Water-gasshift reactions, which are also important for NOX reduction over catalysts 

combining Pd and ceria, can be blocked by sulfur poisoning and may be responsible 

for observations of reduced NOX activity over Pd/ceria catalysts even with exposure 

to fairly low levels of sulfur (equivalent to 15 ppm in gasoline). 

Operating the catalyst at a sufficiently high temperature under net reducing 

conditions (e.g., air-to-fuel equivalence that is net fuel-rich of stoichiometry) can 

effectively release the sulfur oxides from the catalyst components. Thus, regular 

operation at sufficiently high temperatures at rich air-to-fuel ratios can minimize the 

effects of fuel sulfur levels on catalyst active materials and catalyst efficiency. As 

discussed in Section IV.A.6, however, it cannot completely eliminate the effects of 

sulfur poisoning. In current vehicles, desulfurization conditions occur typically at 

high loads when there is a degree of commanded enrichment (i.e., fuel enrichment 

commanded by the engine management system primarily for protection of engine 

and/or exhaust system components). A study of Tier 2 vehicles in the in-use fleet 

recently completed by EPA shows that emission levels immediately following high 

speed/load operation is still a function of fuel sulfur level, suggesting that lower 

gasoline sulfur levels will bring emission benefits unachievable by catalyst 
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desulfurization procedures alone. 488 For example, if a vehicle operates on gasoline 

with less than 10 ppm sulfur, exhaust emissions stabilize over repeat FTP tests at 

emissions near those of the first FTP that follows the high speed/load operation and 

catalyst desulfurization. Continued operation on gasoline with 10 ppm average 

sulfur content or lower is necessary after catalyst desulfurization in order to achieve 

emissions reductions with the current in-use fleet.489 As also discussed in Section 

IV.A.6, the emission effects study performed by SGS also suggests that negative 

effects of exposure to a somewhat higher sulfur level (80 ppm in this case) are 

largely reversible for Tier 2 vehicles, and thus, suggests that reducing fuel sulfur 

levels nationwide will bring significant immediate benefits by reducing emissions 

of the existing fleet. Finally, to the extent such conditions do not occur today as 

part of normal driving for vehicles in the in-use fleet, there is no practical way to 

modify such existing vehicles to do so. Thus, reducing fuel sulfur levels has been 

the primary regulatory mechanism to minimize sulfur contamination of the catalyst 

and ensure optimum emissions performance over the useful life of a vehicle and is 

the only effective means for the in-use fleet. 

For Tier 3 vehicles, there are several reasons why regular operation at the 

high exhaust temperatures and rich air-to-fuel ratios necessary for catalyst 

desulfurization is not desirable and may not be possible. The temperatures 

necessary to release sulfur oxides are high enough to lead to thermal degradation of 

the catalyst over time through thermal sintering of active materials. Sintering 

reduces the surface area available to participate in reactions. Additionally, it is not 

always possible to maintain these catalyst temperatures (because of cold weather, 

idle conditions, light load operation). Also, the rich air-to-fuel ratios necessary for 

sulfur removal can result in increased PM, NMOG and CO emissions.

The impact of gasoline sulfur has become even more important as vehicle 

emission standards have become more stringent. Some studies have suggested an 

increase in catalyst sensitivity to sulfur when standards increase in stringency and 

emissions levels decrease.490, 491 Emission standards under the programs that 

preceded the Tier 2 program (Tier 0, Tier 1 and National LEV, or NLEV) were high 

enough that the impact of sulfur was considered negligible. The Tier 2 program 

recognized the importance of sulfur and reduced the sulfur levels in the fuel from 

 

488 The Effects of Ultra-Low Sulfur Gasoline on Emissions from Tier 2 Vehicles in the In-Use Fleet, 

EPA-420-R-14-002.

489 See Preamble Section IV.A.6.c and Chapter 1 of the RIA (Section 1.2.3.2) for more details on this 

study and its results. 

490 Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. (2000). Fuel Property Requirement 

for Advanced Technology Engines. SAE Technical Paper 2000-01-2019.

491 Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel Sulfur on FTP NOX Emissions from a 

PZEV 4 Cylinder Application. SAE Technical Paper 2011-01-0300. 
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around 300 ppm to 30 ppm in conjunction with the new emission standards. At that 

time, very little work had been done to evaluate the effect of further reductions in 

fuel sulfur – especially on in-use vehicles that may have some degree of catalyst 

deterioration due to real-world operation. As also shown in Section IV.A.6, there 

are currently available data from various studies and testing on Tier 2 vehicles that 

indicate that emissions performance is sensitive to sulfur levels in gasoline. 

Specifically, the MSAT studies of Tier 2 vehicles showed the emission reduction 

potential of lower sulfur fuel on Tier 2 and later technology vehicles over the FTP 

cycle. For instance, there was a 48 percent increase in NOx over the FTP when 

gasoline sulfur was increased from 6 ppm to 32 ppm. Further, emissions data from 

testing conducted by EPA on a representative subset of vehicles (after clean-out 

procedures) on 28 ppm and 5 ppm fuel with accumulated mileage, showed Bag 2 

NOX emissions were 47 percent lower on the 5 ppm fuel as compared to 28 ppm 

fuel. The reductions found in these studies are also consistent with the MSAT and 

Umicore studies on Tier 2 vehicles in terms of the magnitude of NOX and HC 

reductions when switching from 28 ppm to 5 ppm fuel. The results of the emission 

effects study performed by SGS and included with API’s comments on the Tier 3 

proposal are also consistent with the findings of EPA’s Tier 2 in-use study, namely

that emissions performance is sensitive to fuel sulfur level. In sum, these studies 

confirm our view that reducing sulfur levels in gasoline from current levels to levels 

in the range of today’s final gasoline sulfur standards will be expected to achieve 

significant reductions in emissions of NOX, hydrocarbons, and other pollutants of 

interest from the in-use fleet.

The importance of lower sulfur gasoline is also demonstrated by the fact that 

vehicles certified to California SULEV typically certify to higher bins for the 

federal Tier 2 program. Light-duty vehicles certified to SULEV under LEV II are 

more typically certified federally to Tier 2 Bin 3, Bin 4 or Bin 5. In particular, nonhybrid vehicles certified to California SULEV are not certified to federal Tier 2 Bin 

2 emissions standards even though the numeric limits for NOX and NMOG are 

shared between the California LEV II and federal Tier 2 programs for SULEV and 

Bin 2. Confidential business information shared by the auto companies indicate 

that the primary reason is an inability to demonstrate compliance with SULEV/Bin 

2 emission standards after vehicles have operated in-use on gasoline with greater 

than 10 ppm sulfur and with exposure to the higher sulfur gasoline sold nationwide. 

While vehicles certified to the SULEV and Tier 2 Bin 2 standards both demonstrate 

compliance using certification gasoline with 15-40 ppm sulfur content, in-use 

compliance of SULEV vehicles in California occurs after significant, sustained 

operation on gasoline with an average of 10 ppm sulfur and a maximum cap of 20 

ppm sulfur while federally certified vehicles operate on gasoline with an average of 

30 ppm sulfur and a maximum cap of 80 ppm sulfur. Although the SULEV and 

Tier 2 Bin 2 standards are numerically equivalent, the increased sulfur exposure of 

in-use vehicles certified under the federal Tier 2 program results in a need for a 
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higher emissions compliance margin to take into account the impact of in-use 

gasoline sulfur on full useful life vehicle emissions.

As further discussed in Section IV.A.6.d, available studies and testing also 

confirm that there is significantly increased sensitivity of exhaust emissions to 

gasoline sulfur by vehicles with exhaust emission control technologies that we 

expect to be used with vehicles complying with today’s Tier 3 emissions studies. 

Specifically, available test data from the Ford Motor Company developmental 

heavy-light-duty truck and the Umicore Autocat 2009 Chevrolet Malibu PZEV 

show more increases in NOx and NMOG+NOx emissions with increased gasoline 

sulfur than was observed for Tier 2 vehicles. Similarly, test data from the EPA Tier 

3 prototype 2012 Chevrolet Silverado heavy-light duty pickup also showed 

increased NMOG+NOx emissions and one exceedance of today’s final Bin 30 

exhaust emissions standards. In sum, available test data indicate that increasing 

gasoline sulfur levels from 10 ppm to 30 ppm on vehicles meeting Tier 3 standards 

essentially negated the entire benefit of the advances in emissions control 

technology that were applied to meet Tier 3 developmental goals. Because of the 

resulting need to reach near-zero NOX levels to offset NMOG emissions, any

significant degradation in NOX emissions control over the useful life of the vehicle 

will likely prevent some if not most larger vehicles from reaching a combined 

NMOG+NOX level low enough to comply with the 30 mg/mi fleet-average 

standard. Any degradation in catalyst performance due to gasoline sulfur will also 

reduce or eliminate the margin necessary to ensure in-use compliance with the Tier 

3 emissions standards. Thus, the impact of gasoline sulfur poisoning on exhaust 

catalyst performance and the relative stringency of the Tier 3 exhaust emissions 

standards, particularly for larger vehicles and trucks, when considered together 

make a compelling argument for the virtual elimination of sulfur from gasoline. 

As discussed in Section V.B, the average 10 ppm gasoline sulfur standard is 

feasible and is the level that appropriately balances costs with the emission 

reductions that it provides and enables. Not only will a 10 ppm sulfur standard 

enable vehicle manufacturers to certify their entire product line of vehicles to the 

Tier 3 fleet average standards, but reducing gasoline sulfur to 10 ppm will better

enable these vehicles to maintain their emission performance in-use over their full 

useful life. Higher sulfur levels would make it impossible for vehicle 

manufacturers to meet the Tier 3 standards, and would forego the very large 

immediate reductions from the existing fleet. Reducing the sulfur level below 10 

ppm would further reduce vehicle emissions and allow the Tier 3 vehicle standards 

to be achieved more easily. However, we believe that a 10 ppm average standard is 

sufficient to allow vehicles to meet the Tier 3 standards. Further, as discussed in 

Sections V.B and IX.B there are significant challenges associated with reducing 

sulfur below 10 ppm.
Page 389 of 529

3. Section 211(c)(2)(B)

Section 211(c)(2)(B) requires that, prior to adopting a fuel control based on 

a significant impairment to vehicle emission-control systems, EPA consider 

available scientific and economic data, including a cost benefit analysis comparing 

emission-control devices or systems which are or will be in general use that require 

the proposed fuel control with such devices or systems which are or will be in 

general use that do not require the proposed fuel control. As described above and in 

the RIA (Chapter 1), we conclude that the emissions control technology expected to 

be used to meet Tier 3 standards would be significantly impaired by operation on 

gasoline with annual average sulfur levels greater than 10 ppm. Our analysis of the 

available scientific and economic data can be found below in Section VII. The RIA 

includes a detailed analysis of the environmental benefits of the emission standards 

(Chapters 6 and 8), an analysis of the technological feasibility and cost of 

controlling sulfur to the levels established in the final rule (Chapters 4 and 5), and a 

cost analysis of the sulfur control and motor vehicle and engine emission standards 

(Chapter 9). Under section 211(c)(2)(B), as just noted, EPA is also required to 

compare the costs and benefits of achieving emission standards through emissioncontrol systems that would not be sulfur-sensitive, if any such systems are or will be 

in general use. We have determined that there are not (and will not be in the 

foreseeable future) emission control devices available for general use in motor 

vehicles that can meet the emission standards and would not be significantly

impaired by gasoline with current gasoline sulfur levels. Emissions cannot be 

reduced anywhere near the magnitude contemplated by the emission standards 

without the application of the kind of emissions control technology discussed in this 

final rule.

4. Section 211(c)(2)(C)

Section 211(c)(2)(C) of the Clean Air Act requires that prior to prohibiting a 

fuel or fuel additive, EPA establish that such prohibition will not cause the use of 

another fuel or fuel additive “which will produce emissions which endanger the 

public health or welfare to the same or greater degree” than the prohibited fuel or 

additive. This finding is required by the Act only prior to prohibiting a fuel or 

additive, not prior to controlling a fuel or additive. Since EPA is not prohibiting use 

of gasoline sulfur, but rather is controlling the level of sulfur in these fuels, this 

finding is not required for this rulemaking. However, EPA does not believe that the 

gasoline sulfur controls will result in the use of any other fuel or additive that will 

produce emissions that will endanger public health or welfare to the same or greater 

degree as the emissions produced by gasoline with current sulfur levels. Unlike the 

case of unleaded gasoline in the past, where lead performed a primary function by

providing the necessary octane for the vehicles to function properly, sulfur does not 

serve any useful function in gasoline. It is not added to gasoline, but occurs 

naturally in the crude oil into which gasoline is processed. Were it not for the 

expense of sulfur removal, it would likely have been removed from gasoline years 
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ago in order to improve the maintenance and durability characteristics of motor 

vehicle engines. 

We are also adopting the various controls for DFE, other oxygenates, butane 

and pentane blended into gasoline, and gasoline additives, under our authority in 

section 211(c)(1). As explained above, these controls are necessary to prevent 

emissions products that may endanger the public health or welfare or impair to a 

significant degree the performance of any emission control device or system. This 

action basically extends various controls on gasoline to DFE, other oxygenates, 

butane, and gasoline additives. The reasons for adopting the controls for gasoline 

apply as well to adopt the controls for DFE, other oxygenates, butane, and gasoline 

additives.
Page 391 of 529

VI. Technical Amendments and Regulatory 

Streamlining

In addition to adopting new Tier 3 vehicle standards and new gasoline sulfur 

standards, we are also finalizing a range of technical amendments and regulatory

streamlining actions as part of the Regulatory Review initiative. Some of these may

have some bearing on implementation of the Tier 3 vehicle and fuel standards, 

while others deal with other aspects of EPA’s existing fuel and vehicle regulations.

EPA is also synchronizing several different reporting deadlines under 

various regulations affecting transportation and motor vehicle fuels and fuel 

additives. This action will reduce regulatory burdens by aligning reporting 

deadlines across several programs and lays the foundation for the overall goal of 

combining various fuels reports together into a single, simplified electronic format

in the near future. 

A. Fuel Program Amendments

The following sections discuss the changes being finalized today to the fuels 

regulations in 40 CFR parts 79 and 80. Some of these changes are technical 

amendments to correct minor errors or inconsistencies in the regulations; others are 

to address areas in the regulations that needed clarification and/or streamlining; still 

others are to provide additional flexibility. 

With regard to regulatory streamlining, the majority of these items involve 

providing additional clarity, removing or updating outdated provisions, and 

decreasing the frequency and/or volume of reporting burden where data are either 

no longer needed or are redundant in light of other EPA fuels programs. In general, 

we believe that these changes are straightforward and will reduce burden on 

industry with no expected environmental impact. 

We are also finalizing regulations to adopt a performance-based 

measurement systems approach to fuel parameter testing as discussed in Section 

VI.A.2, to expand the downstream butane blending provisions to allow for pentane 

blending as discussed in Section VI.A.3, and to accept Top Tier test data under the 

gasoline deposit control program as discussed in Section VI.A.4. We may 

undertake additional regulatory streamlining in a future action following additional 

stakeholder interactions, as discussed in Section VI.A.5.

Below is a table listing the provisions that we are amending in today’s 

action. We have provided additional explanation for those amendments that 

warrant additional explanation in the following sections.

Table VI-1 Summary of Regulatory Streamlining and Technical Amendments

Section Description
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Varied Various sections amended to update references to test methods 

(see Section VI.A.1.a.iii).

79.5 Revised periodic reporting requirements.

80.2 Revised and added definitions.

80.8 Amended to update sampling test methods, and to state to 

which fuels §80.8 applies.

80.46 Revised measurement of RFG fuel parameters.

80.47 Added Performance-Based Test Method Approach.

80.65 Amended to reduce complex model test parameters and 

reporting and to accommodate RVP adjustment when blender 

grade pentane is blended into gasoline downstream of the 

refinery.

80.65(f)(5) Added to allow for designation of an alternative lab.

80.66(f) Amended to delete references to appendices that no longer 

exist.

80.74 Amended to reflect the recordkeeping requirements for entities 

in the blender grade pentane distribution system.

80.75 Revised RFG reporting requirements. Added reporting 

requirements for produces and importers of blender grade 

pentane.

80.77 Amended to reflect the product transfer document requirements 

for entities in the distribution system for blender grade pentane.

80.80 Amended to reflect the potential penalties requirements for 

entities in the distribution system for blender grade pentane.

80.82 Amended to apply butane blending provisions to entire part 80 

and to revise RVP test method.

80.85 Added the requirements for downstream pentane blending.

80.86 Added the requirements for producers and importers of blender 

grade pentane.

80.87 Added the controls and prohibitions for entities in the blender 

grade pentane distribution system.

80.101 Revised measurement of conventional gasoline fuel parameters.

80.105 Amended to require identification of test methods used in 

refiner reports, and to add reporting requirements for butane 

blenders.

80.161(b)(1)(ii)(A)(2) Amended to specify the requirements for certification of an 

additive under the new alternative gasoline deposit control

certification option.

80.161(b)(1)(ii)(A)(3) Added to specify the requirements for certification of an 

additive under all gasoline deposit control options other than 
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the alternative certification option. 

80.161(b)(2) Amended to address the submission of gasoline deposit control 

additive samples under the alternative gasoline detergent 

certification option.

80.161(b)(3)(ii)(C) Amended to reflect that documentation of the fuel injector 

deposit demonstration test will be required under the alternative 

gasoline deposit control certification option.

80.161(b)(3)(v) Amended to state that the results of the intake valve and fuel 

injector deposit demonstration test must be submitted to EPA as 

part of the certification letter under the alternative gasoline 

deposit control certification option.

80.161(b)(3)(viii) Amended to change “PFID test” to “fuel injector test”.

80.161(d)(1) Amended to reflect the availability of the alternative gasoline 

deposit control certification option.

80.163(a)(1)(iii) Amended to specify that gasoline deposit control additives may

be certified under the new alternative certification option.

80.164(a) Amended to reference the test fuel requirements under the 

alternative gasoline deposit control certification option.

80.165 Amended to accommodate the alternative deposit control test 

procedures and standards under the alternative gasoline deposit 

control certification option.

80.167(a) Amended to specify how confirmatory testing will be 

conducted for additives certified under the alternative gasoline 

deposit control certification option.

80.176 Added to specify the certification test procedures and standards 

under the alternative gasoline deposit control certification 

option.

80.177 Added to specify the certification test fuels under the alternative 

gasoline deposit control certification option.

80.178 Added to incorporate standards and test methods by reference.

80.330 Revised sampling and testing requirements.

80.340 Amended to add standards for gasoline produced by blending 

pentane into previously certified gasoline.

80.370 Amended to require identification of test method used and 

revises reporting requirements.

80.511 Revised per-gallon and marker requirements.

80.572 Revised labeling requirements. Amended to remove the 

requirement for 15 ppm highway diesel fuel pump labels 

beginning November 30, 2014, and to amend the title to reflect 

that the section includes labeling requirements for dispensers of 

motor vehicle diesel fuel.

80.573 Revised labeling requirements.

80.574 Revised labeling requirements.

80.580 Incorporated test methods by reference.

80.584(b)(3)(i) Amended to correct typographical error (“notc” to “not”).
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80.585 Revised test method approval process.

80.604 Revised reporting requirements.

80.1235(a)(6) Amended to allow refiners and importers who are blending 

blendstock into previously certified gasoline (PCG) an 

alternative to directly test the blendstock for benzene.

80.1235(a)(5) Amended to clarify that refiners and importers may use either 

approach for blendstocks that are blended into either 

conventional gasoline or reformulated gasoline.

80.1235(b)(2) Amended to clarify EPA’s intent (per §80.1238(b)) to allow 

refiners and importers to include oxygenate blended 

downstream of a refinery or import facility in their annual 

average benzene calculation, and to make the section consistent 

with §80.1238(b).

80.1238 Revised benzene determination.

80.1347(a)(5) Amended to require that a negative annual average must be 

reported as zero, and that a refiner must comply with §80.65(i) 

when producing RBOB or RFG and §80.101(g)(9) when 

producing conventional gasoline.

80.1347(a)(6) Added to allow refiners and importers who are blending 

blendstock into previously certified gasoline (PCG) an 

alternative to directly test the blendstock for benzene.

80.1348 Revised sample retention requirements.

80.1349 Added to allow importers who import gasoline into the U.S. by

truck to use the sampling and testing requirements in 40 CFR 

part 80 subpart E as an alternative to the sampling and testing 

requirements in subpart L.

80.1354 Revised reporting requirements for gasoline benzene program.

80.1407 Amended to reflect that pentane blenders incur a renewable 

volume obligation (RVO) for the blender grade pentane they

add to previously certified gasoline (PCG)

80.1451 Revised RFS reporting requirements.

80.1640(d) Added to allow refiners who blend only blender-grade pentane 

into PCG to meet the sampling and testing requirements for 

sulfur by using sulfur test results pursuant to §80.85.

1. Fuels Program Regulatory Streamlining

a. Amendments Related to Reduction of Testing and Reporting of

Complex Model Gasoline Parameters

In §§80.65 and 80.75, we are streamlining and reducing the reformulated 

gasoline (RFG) and conventional gasoline (CG) testing and reporting burden of 

gasoline refiners and importers by reducing the testing and reporting requirements 

of certain fuel parameters associated with the complex model. Currently, for RFG, 
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every batch must be tested for every parameter listed in §80.65. No monthly

compositing of batch samples is allowed for any parameter. For CG, monthly

compositing and batch reporting based on those monthly composites is allowed for 

all parameters except sulfur and benzene. With the phasing out of complex model 

standards492, reduced testing and reporting is appropriate, particularly for RFG. In 

cases where a refiner is subject to only benzene, RVP, and sulfur standards, certain 

parameters no longer need to be tested and reported on an every-batch basis. 

However, the full slate of complex model parameters will still be needed in some 

cases. Specifically, refiners producing RFG during the summer volatile organic 

compound (VOC) control season will still need to use the complex model to 

determine VOC performance, and thus must still measure and report the relevant 

complex model fuel parameters. In addition, small refiners that are subject to the 

delayed compliance option for the 0.62 volume percent benzene standard will have 

to use the complex model (and thus measure all complex model parameters) until 

2015 for CG MSAT1 compliance.493

Currently, there are 17 complex model parameters on the RFG/anti-dumping 

batch report. We are reducing testing and reporting requirements for some of these 

parameters for RFG, CG or both. For both RFG and CG, we are eliminating testing 

and reporting of American Petroleum Institute (API) gravity. In addition, we are 

finalizing that oxygenates need not be reported unless the refiner’s gasoline 

includes oxygenates or the refiner is including downstream added oxygenate in its 

compliance calculations. Apart from being necessary for use in the complex model, 

these parameters have little use for program compliance. Commenters agreed with 

the elimination of testing of API gravity and oxygenates. 

For winter RFG, we are eliminating the requirement to test and 

report aromatics, distillations and olefins on an every batch basis and instead will 

allow testing and reporting of monthly composites. Commenters from the refining 

industry strongly suggested that we eliminate testing of these parameters altogether, 

since they are not needed, and their elimination would further reduce the burden on 

regulated parties. While we agree that a reduction in burden would occur if refiners 

were not required to test, even on a monthly composite basis, for these parameters, 

the many interconnected aspects of the RFG program make any seemingly 

innocuous change potentially fraught with unintended consequences. Thus, we are 

deferring the consideration of any action to completely eliminate the testing of these 

parameters to any future fuel program restructuring, as discussed in Section VI.A.5.

Sulfur and benzene will continue to be tested and reported on an every batch 

basis as these values are necessary for the Tier 2 and Tier 3 gasoline sulfur and 

MSAT2 benzene programs. All summer complex model parameters will still be 

 

492 Per §§80.41(e) and (f), and §80.101(c), applicable NOx and toxics emissions requirements are 

superseded by the Tier 2 gasoline sulfur standards and MSAT2 benzene standards, respectively. 

493 61 FR 17230 (March 29, 2001).
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required to be tested and reported on an every batch basis because of the summer 

VOC requirement for RFG. For CG, only benzene, sulfur, and any oxygenates that 

are actually included in the gasoline batch must be tested and reported on an everybatch basis (except for refiners that are still subject to a complex model toxics 

standard; they must test all parameters but may use monthly composite testing and 

reporting except for sulfur and benzene, and oxygenate, where applicable). In the 

proposal, we stated “...values for aromatics, olefins, and distillation terms may

continue to be determined from monthly composites.” Some commenters thought 

the term “may” in that sentence meant that reporting on those parameters at all is 

optional. That is an incorrect interpretation. We were conveying that obligated 

parties may use either monthly composites or batch testing. But those parameters 

must still be measured and reported. Commenters in the refining industry do not 

think these parameters need to be measured at all for parties subject to the MSAT2 

benzene standard, as compliance with that standard is not dependent on aromatic, 

olefin, or distillation values. As mentioned earlier, there are several areas of the 

RFG and/or anti-dumping programs where testing and reporting burden could likely

be reduced; however, we have not fully evaluated the implications of changing the 

current requirements, and thus we are leaving consideration of such changes to the 

broader program restructuring discussed in Section VI.A5. Nonetheless, the

changes that are finalized today will substantially reduce the testing and reporting 

burden on regulated parties.

b. Amendments Related to Reporting Dates

EPA is amending various provisions in 40 CFR parts 79 and 80 to reduce 

the number of different reporting deadlines that regulated parties must meet and to 

enable the future use of a unified and simplified reporting form. Currently under 40 

CFR parts 79 and 80, there are ten separate cyclical reporting dates each year 

(eleven in a leap year). Streamlining reporting deadlines will allow EPA to develop 

a single, user-friendly, electronic form that will collect all required data, 

maximizing the capability of electronic reporting to provide reuse of data and avoid 

duplicate data submission. EPA’s goal is to simplify reporting and reduce the 

number of hours parties spend preparing and submitting reports while 

simultaneously improving data received from stakeholders. This overall effort 

responds to Executive Orders 13563 and 13610, which direct government agencies 

to simplify rules and to achieve reductions in paperwork and reporting burdens, and 

is part of EPA’s agency-wide effort to streamline regulatory reporting requirements.

We are amending these deadlines so that all affected programs use the same 

four reporting deadlines. Programs that will be affected by this change include:

 the fuels and fuel additives registration program (40 CFR part 79, subpart 

A);

 the Reformulated Gasoline and Anti-Dumping program (40 CFR part 80, 

subparts D and E);
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 the Gasoline Sulfur program (40 CFR part 80 subpart H);

 the Motor Vehicle, Nonroad, Locomotive, and Marine Diesel program (40 

CFR part 80 subpart I);

 the Gasoline Benzene program (40 CFR part 80 subpart L);

 the Renewable Fuel Standard program (40 CFR part 80 subparts K and M); 

and

 the Tier 3 program being finalized today (40 CFR part 80 subpart O). 

We are finalizing that reporting deadlines will be standardized as follows: 

June 1, for all reports covering quarter 1 of the compliance year (January through 

March); September 1, for quarter 2 (April through June); December 1, for quarter 3

(July through September); and March 31 for quarter 4 (October through December). 

End-of-year compliance reports will also be due on March 31. These changes will

either delay or maintain current deadlines for nearly all required reports. Deadlines 

for all other annual reports will either be maintained if they matched the new 

quarterly deadline, or extended to match the new quarterly deadline. It should be 

noted that even with the changes finalized today, respondents will still have the 

option to report earlier than any given deadline. Commenters generally agreed with 

the proposed date changes. Some commenters in the refining industry suggested 

eliminating all quarterly reporting for RFG if winter aromatics, olefins and 

distillation are no longer required to be reported as they suggested. These values 

are normally reported in the 1st and 4th quarters. As one commenter stated, “In 

addition, there is no point in splitting up summer RFG/RBOB reporting between the 

2

nd and 3rd quarters.” As noted above, winter aromatics, olefins and distillation are 

still required to be reported, albeit on a monthly composite basis. Thus, the need 

for quarterly reporting remains. However, we expect that the need for quarterly 

reports will be evaluated as part of the broader program restructuring discussed in 

Section VI.A.5.

EPA proposed not to include “Attest Engagements” (currently due May 31 

of the following year) or reporting related to specific events under the Fuels 

Program, such as trading Renewable Identification Numbers (RINs) in EPA’s 

Moderated Transaction System (EMTS), in the reporting revisions described above. 

Rather, all reporting deadlines for Attest Engagements and reporting specific events 

will remain the same. Some commenters communicated that if the annual and 

fourth quarter reporting deadlines were to be extended to March 31 of each year, 

then the attest engagement date should also be shifted one month from May 31 to 

June 30 to allow sufficient time for the significant data-gathering and 

communications required to complete those engagements. EPA is not changing the 

compliance period associated with the new extended reporting date, but rather, is 

simply allowing additional time for data review, preparation and reporting. EPA 

does not believe that extending the attest engagement date is necessary because 

companies have the flexibility to use the extra reporting time to begin preparation 
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for the attest engagement if they prefer. As stated previously, the extension to 

reporting deadlines does not preclude stakeholders from reporting before the 

deadline. EPA is not extending the date for attest engagements from May 31 to 

June 30. That said, EPA is streamlining reporting dates to aid in our development 

of a single electronic reporting format and is updating the due date for attest 

engagements found in part 80 from May 31 to June 1. This change will not affect 

compliance or increase burden of reporting entities. Rather, the purpose of 

streamlining various reporting deadlines is to ease reporting burden and help aid 

EPA in the development and implementation of a single electronic reporting format.

We are also correcting a typographical error in 40 CFR 80.1451(f)(2) and 

clarifying that reports are to be signed by the “responsible corporate officer.” One 

commenter suggested that EPA revise the instances when a “responsible corporate 

officer” signature is required, and when perhaps someone else in the company can 

sign. The example given in the comment was that a phone number change should 

not require a “responsible corporate officer” signature, as getting this level of 

signature can be burdensome, and the company can have appropriate delegations in 

place when someone other than the “responsible corporate officer” is the signatory. 

While we understand the concern expressed, EPA does not believe a regulatory

action is necessary to address this concern but rather believes this issue is best 

addressed via administrative procedures. EPA plans to further evaluate this specific 

concern and similar “responsible corporate officer” issues and address the concerns 

in the future, outside of the regulatory framework.

Finally, we are addressing a typographical error in the regulatory text. 

Specifically, incorrect references under 40 CFR 79.5(a)(2) and 79.5(b) are being 

addressed as well as clarification being added.

c. Amendments to Update Fuel Parameter Test Methods

Refiners, importers and oxygenate blenders producing gasoline and diesel 

motor vehicle fuel are required to test RFG, CG and diesel fuel for various fuel 

parameters including aromatics, benzene, distillation, olefins, oxygenate content, 

RVP, and sulfur. As stated in the proposal, a number of relevant regulatory 

provisions had references to test methods that have been revised and updated. 

Several comments were received indicating that since the time of the proposal, 

some of the proposed updates have been further revised and updated and the desire 

was expressed for the regulated community to have the opportunity to use the most 

current version of each of these test methods. Today, we are updating those test 

methods to reflect current test methods in order to ensure that all test methods are 

readily available to the regulated community. ASTM International (ASTM) test 

method D2622 is currently the designated test method for measuring sulfur, in 

gasoline and diesel fuel at the 500 ppm sulfur standard. (§§80.46(a)(1), 

80.580(b)(2).) ASTM test methods D5453, D6920, D3120 and D7039 are currently 

alternative test methods for measuring sulfur in gasoline. (§§80.46(a)(3)(i), 

80.46(a)(3)(ii), 80.46(a)(3)(iii), 80.46(a)(3)(iv).) ASTM test method D5453 is also 

an alternative test method for measuring sulfur in diesel fuel at the 500 ppm sulfur 
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standard, as well as ASTM test method D4294. (§80.580(c)(2).) ASTM test 

method D6667 is currently the designated test method for measuring sulfur in 

butane. (§80.46 (a)(2).) ASTM test methods D4468 and D3246 are currently

alternative test methods for measuring the sulfur content in butane. 

(§§80.46(a)(4)(i), 80.46(a)(4)(ii).) ASTM D1319 is currently the designated test 

method for measuring olefins in gasoline and aromatics in diesel fuel and is also 

allowed as an alternative test method for measuring aromatics in gasoline. 

(§§80.46(b), 80.2(z), and 80.46(f)(3), respectively.) ASTM D6550 is currently an 

alternative test method for measuring olefins in gasoline. (§80.46(b)(2)(i).) ASTM 

test method D5599 is currently the designated test method for measuring 

oxygenates in gasoline. (§80.46(g)(1).) ASTM test method D4815 is currently an 

alternative test method for measuring oxygenates in gasoline. (§80.46(g)(2).) 

ASTM test method D5769 is currently the designated test method for measuring 

aromatics in gasoline. (§80.46(f)(1).) ASTM test method D3606 is currently the 

designated test method for measuring benzene in gasoline. (§80.46(e).) ASTM test 

method D86 is currently the designated test method for measuring the distillation of 

gasoline. (§80.46(d).) ASTM test method D5191 is currently the designated test 

method for measuring the RVP of gasoline. (§80.46(c).) ASTM test method D976 

is currently the designated test method for measuring the Cetane Index of diesel 

fuel. (§80.2(w).) ASTM standard practice D4057 is currently the manual sampling 

standard practice for petroleum and petroleum products. (§80.8(a).) ASTM 

standard practice D4177 is currently the automatic sampling standard practice for 

petroleum and petroleum products. (§80.8(b).) ASTM standard practice D5842 is 

currently the RVP sampling standard practice for fuels. (§80.8(c).) ASTM 

standard practice D5854 is currently the composite sampling standard practice for 

petroleum and petroleum products. (§80.8(a).)

Table VI-2 lists the designated analytical test methods and alternative 

analytical test methods for RFG, CG and diesel fuel that we are updating in today’s 

action. The Agency has reviewed these updated ASTM test methods and believes 

that the revisions contained in them will result in improvements in the utilization of 

these test methods for the regulated industry. We also believe that our revisions to

these test methods will not result in significant changes that would cause a user of 

an older version of the same method to incur increased compliance costs. 

Moreover, all of the revisions were deemed necessary by ASTM so that 

improvements in the test method’s procedures would ensure better operation for the 

user of the test method. Thus, EPA is today updating the regulations for the 

following ASTM test methods: 1) ASTM D2622-10, the designated test method for 

measuring sulfur in RFG, CG, and alternative test method for diesel fuel at the 500 

ppm sulfur standard; 2) ASTM D3120-08, alternative test method for sulfur in 

gasoline; 3) ASTM D4294-10, alternative test method for sulfur in diesel fuel at the 

500 ppm sulfur standard; 4) ASTM D5453-12, alternative test method for sulfur in 

gasoline and diesel fuel at the 500 ppm sulfur standard; 5) ASTM D6667-10, 

designated test method for sulfur in butane; 6) ASTM D4468-85(Reapproved 

2011), alternative test method for sulfur in butane; 7) ASTM D3246-11, alternative 

test method for sulfur in butane; 8) ASTM D1319-13, designated test method for 
Page 400 of 529

measuring olefins in gasoline and aromatics in diesel fuel, as well as the alternative 

test method for measuring aromatics in gasoline; 9) ASTM D6550-10, alternative 

test method for measuring olefin content in gasoline; 10) ASTM D4815-13, 

alternative test method for measuring oxygenate content in gasoline; 11) ASTM 

D5599-00 (2010), the designated test method for measuring oxygen content in 

gasoline; 12) ASTM D5769-10, the designated test method for measuring aromatics 

in gasoline; 13) ASTM D3606-10, the designated test method for measuring 

benzene in gasoline; 14) ASTM D86-12, the designated test method for measuring 

distillation properties of gasoline; 15) ASTM D5191-12, the designated test method 

for measuring the RVP of gasoline; 16) ASTM D976-06(2011), the designated test 

method for measuring the Cetane Index of diesel fuel; and 17) ASTM D7039-13, 

alternative test method for measuring sulfur in gasoline.

Table VI-2 Designated & Alternative ASTM International Analytical Test 

Methods Under RFG, CG & Diesel Motor Vehicle Fuel Programs

Fuel Parameter ASTM Analytical Test Method

Sulfur (designated test 

method for gasoline)

ASTM D2622-10, entitled “Standard Test Method for 

Sulfur in Petroleum Products by Wavelength Dispersive 

X-Ray Fluorescence Spectrometry”

Sulfur (designated test 

method for 500 ppm 

sulfur diesel)

ASTM D2622-10, entitled “Standard Test Method for 

Sulfur in Petroleum Products by Wavelength Dispersive 

X-Ray Fluorescence Spectrometry”

Sulfur (alternative test 

method for gasoline)

ASTM D3120-08, entitled, “Standard Test Method for 

Trace Quantities of Sulfur in Light Petroleum 

Hydrocarbons by Oxidative Microcoulometry”

Sulfur (alternative test 

method for 500 ppm 

sulfur diesel)

ASTM D4294-10, entitled, “Standard Test Method for 

Sulfur in Petroleum Products by Energy Dispersive X-ray

Fluorescence Spectrometry”

Sulfur (alternative test 

method for gasoline)

ASTM D5453-12, entitled, “Standard Test Method for 

Determination of Total Sulfur in Light Hydrocarbons, 

Spark Ignition Engine Fuel, Diesel Engine Fuel, and 

Engine Oil by Ultraviolet Fluorescence”

Sulfur (alternative test 

method for 500 ppm 

sulfur diesel)

ASTM D5453-12, entitled, “Standard Test Method for 

Determination of Total Sulfur in Light Hydrocarbons, 

Spark Ignition Engine Fuel, Diesel Engine Fuel, and 

Engine Oil by Ultraviolet Fluorescence”

Sulfur (designated test 

method for butane)

ASTM D6667-10, entitled, “Standard Test Method for 

Determination of Total Volatile Sulfur in Gaseous 

Hydrocarbons and Liquefied Petroleum Gases by 

Ultraviolet Fluorescence”

Sulfur (alternative test 

method for butane)

ASTM D4468-85(Reapproved 2011), entitled, “Standard 

Test Method for Total Sulfur in Gaseous Fuels by 

Hydrogenolysis and Rateometric Colorimetry”

Sulfur (alternative test 

method for butane)

ASTM D3246-11, entitled, “Standard Test Method for 

Sulfur in Petroleum Gas by Oxidative Microcoulometry”
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Olefins (designated test 

method for gasoline)

ASTM D1319-13, entitled “Standard Test Method for 

Hydrocarbon Types in Liquid Petroleum Products by

Fluorescent Indicator Adsorption”

Aromatics (alternative 

test method for 

gasoline and 

designated test method 

for diesel)

ASTM D1319-13, entitled “Standard Test Method for 

Hydrocarbon Types in Liquid Petroleum Products by

Fluorescent Indicator Absorption,” for diesel fuel, this 

method is the designated test method; for gasoline, this 

method is an alternative test method and if used as an 

alternative method, its results must be correlated to 

ASTM D5769.

Olefins (alternative test 

method for gasoline)

ASTM D6550-10, entitled, “Standard Test Method for the 

Determination of Olefin Content of Gasolines by

Supercritical-Fluid Chromatography”

Oxygen content 

(designated test 

method for gasoline)

ASTM D5599-00 (2010), entitled, “Standard Test Method 

for Determination of Oxygenates in Gasoline by Gas 

Chromatography and Oxygen Selective Flame Ionization 

Detection”

Oxygen content 

(alternative test method 

for gasoline)

ASTM D4815-13, entitled “Standard Test Method for 

Determination of MTBE, ETBE, TAME, DIPE, tertiaryAmyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas 

Chromatography”

Aromatics (designated 

test method for 

gasoline)

ASTM D5769-10, entitled, “Standard Test Method for 

Determination of Benzene, Toluene, and Total Aromatics 

in Finished Gasolines by Gas Chromatography/Mass 

Spectrometry”

Benzene (designated 

test method for 

gasoline)

ASTM D3606-10, entitled, “Standard Test Method for 

Determination of Benzene and Toluene in Finished Motor 

and Aviation Gasoline by Gas Chromatography”

Distillation (designated 

test method for 

gasoline)

ASTM D86-12, entitled, “Standard Test Method for 

Distillation of Petroleum Products at Atmospheric 

Pressure”

Reid Vapor Pressure 

(designated test 

method for gasoline)

ASTM D5191-12, entitled, “Standard Test Method for 

Vapor Pressure of Petroleum Products (Mini-Method)”

Cetane Index 

(designated test 

method for diesel)

ASTM D976-06(2011), entitled, “Standard Test Method 

for Calculated Cetane Index of Distillate Fuels”

Sulfur (alternative test 

method for gasoline)

ASTM D7039-13, entitled, “Standard Test Method for

Sulfur in Gasoline, Diesel Fuel, Jet Fuel, Kerosine, 

Biodiesel, Biodiesel Blends, and Gasoline Ethanol Blends 

by Monochromatic Wavelength Dispersive X-ray

Fluorescence Spectrometry” 
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d. Amendments Related to Downstream Blending and Upstream 

Refiner/Importer Compliance Determination

Today’s rule also clarifies the list of products that are not to be included in a 

refinery’s or importer’s compliance determination under §80.1240. Refiners and 

importers are currently required under §80.1235(b)(2) to exclude oxygenate added 

to finished gasoline, RBOB or CBOB downstream of either the refinery that 

produced the gasoline or the import facility where the gasoline was imported. This 

conflicts with EPA’s intended approach in §80.1238(b), which allows refiners and 

importers to include oxygenate blended downstream of a refinery or import facility

in their annual average benzene calculation, provided the refiner or importer meets 

certain requirements. We are finalizing changes that will allow refiners and 

importers to include oxygenate blended downstream of their facility and that will

make these related sections consistent. EPA received significant support for this 

action from commenters. 

e. Amendments Regarding Previously Certified Gasoline

For compliance with the MSAT2 regulations, for blendstock that is blended 

into previously certified gasoline (PCG), we are providing flexibility for refiners 

and importers by providing an alternative allowing them to directly sample and test 

each batch of blendstock, and treat the blendstock as a produced batch. We are 

adding §80.1347(a)(6) to reflect this alternative. This practice is already allowed 

under the Tier 2 sulfur program (at §80.340(a)(2)). Refiners and importers are 

currently required to determine the benzene content of the PCG before the addition 

of blendstock, determine the benzene content of the combined blend of PCG and 

blendstock, and calculate the properties of the blendstock by treating the PCG as a 

negative volume batch and treating the blended product as a positive batch. Due to 

variability in the benzene test method, the PCG approach can sometimes result in 

calculated blendstock benzene concentrations that are negative, which is physically 

impossible. We are amending the regulations at §80.1235(a)(6) (and adding

§80.1347(a)(6), as mentioned) to allow refiners and importers who blend 

blendstock into PCG to directly test the blendstock for benzene. We expect that this

method will improve accuracy and ensure a positive benzene test result. Also, 

today’s action will clarify that regardless of the approach used, a negative sulfur or 

benzene result cannot be reported; rather, any negative result must be rounded to 

zero. Similarly, no negative annual average result can be reported. We are also 

amending the regulations at §80.1235(a)(5) to clarify that refiners and importers 

may use either approach for blendstocks that are blended into either conventional 

gasoline or reformulated gasoline.

Lastly, we are allowing importers who import gasoline into the United 

States by truck to use the sampling and testing requirements in subpart E for truck 

importers as an alternative to the sampling and testing requirements in subpart L. 
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EPA provided these alternative requirements in subpart E to eliminate the need to 

test every truckload of imported conventional gasoline for all complex model 

parameters, including benzene.494 Since Subpart L also requires importers to test 

every truckload of imported gasoline for benzene, EPA believes it is appropriate to 

allow truck importers of gasoline to use the sampling and testing requirements in 

subpart E as an alternative. We are amending the regulations to provide this 

alternative by adding a new §80.1349. EPA received significant support for this 

action from commenters.

f. Amendments Related to Designation of an Alternative Lab

Refiners have indicated to EPA that significant problems are created when a 

facility’s designated lab is nonoperational and testing cannot be performed at the 

lab during that time period. We are thus finalizing (at §80.65(f)(5)) that a facility

will have the ability to designate a back-up or alternative lab for testing during such 

times. In no case could this alternative lab be used to select the best test result, 

rather it may only be used on those occasions where operational necessity causes a 

need for it (e.g., the normal lab is closed, the apparatus for certain test methods are 

down, or independent lab personnel are not available). EPA received significant 

support for this action from commenters.

g. Amendments Related to De Minimis Reporting Changes

We proposed that parties who submit batch reports would not be required to 

correct inconsequential errors in reporting batch volumes under certain conditions, 

the primary condition being that the discrepancy met the definition of “de minimis”, 

which as proposed, was an amount no greater than the smaller of 500 gallons or one 

(1) percent of the true batch volume. Under the proposal, regulated parties would 

no longer be required to provide a complete resubmission of a compliance report 

when a minor discrepancy of a few barrels was uncovered. We proposed that this 

new provision would apply to reporting for RFG, anti-dumping, gasoline and diesel 

sulfur, and MSAT2. We proposed that it would also apply to the RFS renewable 

volume obligation (RVO), but would only apply to the volume of fuels produced or 

exported that result in a RVO for obligated parties.

We received comments on this proposed change, many of which generally 

agreed with our concept. However, commenters who agreed with the concept 

stated that they believe the proposed levels are so small that they are of little 

practical value, and that a de minimis volume of 500 gallons will almost always be 

less than 1 percent of the true batch volume. In examples provided, commenters 

stated that pipeline batch volumes are approximately 25,000 barrels, and that a 500 

gallon difference equates to a 0.05% difference; 500 gallons on a 250,000 gallon 

refinery production batch equates to 0.005%. Thus, according to the commenters, 

 

494 70 FR 74561 (December 15, 2005).
Page 404 of 529

the 500 gallon limit – which is clearly less than 1% in the two examples - would fail 

to provide the intended relief and would not prevent a party from having to make 

inconsequential volume corrections. These commenters suggested that a de 

minimis threshold value of 0.5 percent be applied regardless of batch size. Several 

commenters also recommended that we delete the proposed regulatory text at 

§80.10 (c) and (d), as the application of a de minimis threshold implies that small 

volume errors in batch reporting are truly inconsequential and do not have an 

impact on compliance with fuel standards, so no separate demonstration of material 

impact should be required. 

One commenter stated that it opposes the de minimis provision with respect 

to the RFS program. According to the commenter, EPA did not provide sufficient 

legal or factual basis for the proposal in order for the public to provide meaningful 

comment. In addition, according to the commenter, the proposed de minimis 

change, if finalized, would allow obligated parties to under report their volume, 

thereby reducing their RVO. The commenter also stated that EPA cannot finalize 

the proposed provision based on other comments it receives because, according to 

the commenter, EPA would still not be satisfying notice and comment 

requirements.

We have decided not to finalize the proposed de minimis provisions at this 

time. One of the primary motivations for proposing the de minimis provision was 

to avoid the need for inconsequential corrections to production volumes that would 

have no impact on compliance with standards that rely on production volumes (e.g., 

average standards and RFS). Late changes to production volumes for whatever 

reason can necessitate simultaneous changes to compliance calculations that, if de 

minimis, would have no meaningful impact on compliance. However, as comments 

highlight, it is has proven difficult to come up with an acceptable de minimis 

threshold that can apply across all potential situations. Furthermore, the proposed 

provision focused only on volume corrections, but in reality our experience 

suggests that corrections often take place for other purposes such as data entry, 

coding, formating or other typographical errors – not only minor corrections to 

reported volume. We believe that adjusting reports for inconsistencies will become 

less burdensome, as EPA intends to transition all reporting to electronic reporting in 

the future. In addition, EPA received input from the regulated community about a 

de minimis provision specifically as it related to the RFS program. As discussed 

below in Section VI.A.1.h, we are finalizing a one-month delay in the RFS 

reporting deadline, which we believe will provide obligated parties with more time 

to review and correct their records and reports, and help to minimize the need for 

late corrections. We will revisit the need for a de minimis threshold in the future if 

these changes prove insufficient.

h. Amendments Related to RFS2 Annual Report Date

EPA is finalizing the proposed changes to the RFS2 annual report date from 

the last day of February to March 31. EPA intended the change would 1) alleviate 

staffing problems for regulated entities because the regulatory requirements are 
Page 405 of 529

often handled by the same personnel and 2) provide relief from the urgent need to 

obtain RINs when small discrepancies in gasoline production or import volumes are 

realized. Another reason for proposing a change to the reporting deadline from the 

last day in February to March 31 was described in Section VI.A.1.b. (Amendments 

Related to Reporting Dates). Streamlining reporting dates will allow EPA to 

develop a single, user-friendly, electronic form that will collect all required data, 

maximizing the capability of electronic reporting to provide reuse of data and avoid 

duplicate data submission. Commenters generally agreed with the proposed date 

change. One commenter pointed out that the staffing issue described would not be 

addressed by the change date because EPA is changing both RFG and Antidumping compliance deadlines to March 31 – same as the RFS2 annual reporting. 

EPA understands the point made but nonetheless, believes that delaying the RFS 

reporting date will give reporting entities additional time and flexibility to review 

data and will have no impact on emissions, air quality, or compliance with the 

standard. EPA also believes that the overarching goal of streamlining reporting 

dates to develop a single electronic reporting format, in and of itself, will provide 

general relief to regulated parties. Comments received generally support this view. 

EPA requested comment on whether or not the same date extension from the 

last day of February to March 31 should apply to those transferring RINs in EMTS 

for satisfying RVOs under the previous compliance year. Some commenters wanted 

to have RIN trading through the new deadline (March 31), while others wanted 

trading to end on the last day of February to allow time for data cleanup which 

could improve compliance and reporting accuracy. One commenter also pointed out 

that changing the RIN trading deadline might have an unforeseen impact on the 

RIN market and suggested EPA carefully consider this possibility before making a 

decision on extending the RIN trading date. EPA agrees that providing enough time 

for data cleanup is important to ensure reporting accuracy and meet compliance 

goals. In addition, EPA understands stakeholders’ concerns about how such a 

change in RIN trading could conceivably impact the RIN trading market dynamics. 

As such, RIN transfers in EMTS for satisfying RVOs under the previous 

compliance year will continue to end on the last day of February. 

i. Amendments to the Highway Diesel Pump Label Requirements 

We are removing the requirement for diesel fuel pump labels for 15 ppm 

highway diesel fuel. Beginning December 1, 2010, all highway diesel fuel was 

required to be 15 ppm or less; thus, highway diesel fuel labels are no longer needed 

to distinguish it from 500 ppm highway diesel fuel. However, we do recognize that 

it may confuse consumers who are accustomed to seeing the highway diesel fuel 

pump labels if those labels were to disappear, thus, retail and wholesale purchaserconsumer facilities will be free to continue labeling to eliminate confusion if they so 

choose. The elimination of this requirement from the regulations does not preclude 

retail and wholesale purchaser-consumer facilities from keeping 15 ppm highway

diesel fuel labels, it only eliminates the EPA requirement that such labels must be 

present. 
Page 406 of 529

Comments from parties in the fuels industry expressed support for this 

proposal. Additionally, we received a comment suggesting that the requirement of 

vehicle labeling for 15 ppm highway diesel fuel (ultra low sulfur diesel fuel, or 

“ULSD”) should also be removed in conjunction with this change, as the vehicle 

labels would be unnecessary for the same reasons noted for the pump labels. We 

note that this change was in fact made for vehicles under 14,000 lbs GVWR in a 

previous rulemaking for MY 2014 and later vehicles (see 40 CFR 86.1807-01(h)). 

Further, in today’s action, we are discontinuing the ULSD labels for MY 2014 and 

later vehicles above 14,000 lbs GVWR at 40 CFR 86.007-35(c).

2. Performance-Based Measurement Systems (PBMS)

Today we are finalizing a performance-based measurement system (PBMS) 

for chemical and physical properties of fuels regulated by EPA’s motor vehicle and 

engine fuel programs. Specifically, they are gasoline properties at §80.46, gasoline 

sulfur at §80.195, and diesel fuel properties at §80.2(z). At proposal, we explained 

that PBMS would set forth procedures and criteria for those laboratories making 

measurements to demonstrate compliance with fuels regulations to qualify

alternative analytical test methods. We also explained that it would set minimum 

statistical quality control (SQC) requirements, based on standard industry practices, 

and that laboratories must maintain and document the precision and accuracy of 

analytical methods used in the context of this program. We further explained that 

EPA envisioned that PBMS would provide additional flexibility to the regulated 

industry in choosing test methods and foster innovation and improvement in the 

precision and accuracy of the measurement of motor vehicle and engine fuel 

properties while not reducing the emission benefits that result from these fuel 

programs. We reasoned that PBMS should also provide cost savings to the 

regulated industry by providing rapid access to newly-developed test methods with 

superior speed and ease of analysis. This is because some of these newer methods 

use less-expensive easier to automate instrumentation and smaller quantities of 

consumables, thus, reducing both operating costs and environmental impact (78 FR 

29953). Table VI-3 below lists fuel parameters and their corresponding designated 

test methods that we proposed to update.

Table VI-3 Designated Analytical Test Methods for Gasoline and Diesel Fuel

Fuel Parameter Designated Analytical Method

Sulfur in gasoline ASTM D 2622-10

Sulfur in butane ASTM D 6667-10

500 ppm Sulfur Diesel Fuel ASTM D 2622-10

Olefins in gasoline ASTM 1319-10

Reid vapor pressure (RVP) in 

gasoline

ASTM D 5191-10b, with the following 

correlation equation:

RVP psi = (0.956 * X) - 0.347

RVP kPa = (0.956 * X) - 2.39

where:

X = total measured vapor pressure in psi or 
Page 407 of 529

kPa.

Distillation in gasoline ASTM D86-11a

Benzene in gasoline ASTM D 3606-10, except that instrument 

parameters shall be adjusted to ensure 

complete resolution of benzene, ethanol, 

and methanol peaks.

Aromatics in gasoline ASTM D 5769-10, except that sample 

chilling requirements in section 8 of this 

standard are optional.

Oxygen and oxygenate content in 

gasoline

ASTM D 5599-00 (2010)

Aromatics in diesel fuel ASTM D1319-10

a. Overview of Proposed Program Requirements

As explained at proposal, in a June 29, 2004 rulemaking, EPA specified a 

performance-based approach for measuring diesel sulfur at 15 ppm and 500 ppm 

and removed previous requirements that had specified particular designated and 

alternative methods for 15ppm diesel sulfur.

495

 We decided, in that rulemaking, to 

offer two options for test methods for diesel sulfur at the 500 ppm level. The first 

option required use of either the designated test method or specific alternative test 

methods.

496

 The second option was for a test method to meet performance based 

requirements similar to those adopted for 15ppm diesel sulfur.

497

 We proposed 

extending the performance-based approach to method selection and qualification to 

other parameters besides diesel sulfur, with modifications appropriate to 

accommodate the differences among fuel parameters. Today, consistent with our 

proposal, we are finalizing requirements for PBMS subject to a few revisions of 

certain requirements that we are making in response to comments on our proposal.

Specifically, in today’s action we are setting forth requirements that 

laboratories should use to demonstrate the precision498 and accuracy499 of chosen 

fuel parameter measurement methods. As also explained at proposal, PBMS as 

finalized would: 1) require individual laboratories to demonstrate adequate 

 

495 See 40 CFR 80.584 and 80.545.

496 See 40 CFR 80.580(c)(2).

497 See 40 CFR 80.584(a)(2), 40 CFR 80.584(b)(2)(i) through 40 CFR 80.584(b)(2)(iii), and 40 CFR 

80.585.

498 Precision – the amount of consistency in a set of measurements performed on the same material. 

ASTM repeatability and reproducibility are examples of measures of precision. ASTM 

Repeatability (“r”) – the difference between successive test results obtained by the same operator 

with the same apparatus under constant operating conditions on identical test material. ASTM 

Reproducibility (“R”) – the difference between two single and independent test results obtained by 

different operators working in different laboratories on identical test material using the same method.

499 Accuracy – the closeness of a single measurement to its true value of what is being measured.
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measurement quality, 2) allow laboratories to choose methods that meet their own 

needs, provided they can meet quality criteria, 3) prescribe criteria rather than 

specific methods500, and 4) require all laboratories making regulatory measurements 

to establish and maintain a statistical quality control program (72 FR 29955). EPA

continues to believe that PBMS will not compromise on either precision or 

accuracy relative to the system that exists under current regulations. We have also 

incorporated the standards and practices of Voluntary Consensus Standard Based 

(VCSB) organizations wherever feasible.

Today’s requirements apply to the qualification of analytical test 

instrumentation and methods used to measure various characteristics of individual 

fuel samples. Consistent with our proposal, it does not apply to sampling methods 

or in-line blending methods. The Agency received several comments asking to 

extend PBMS to in-line blending methodologies expeditiously. As earlier 

explained, today’s final action does not extend to sampling methods or in-line 

blending methods. This is because, in-line blending already has a certification 

process that sets forth qualification criteria that take into account the unique 

combinations of sampling, control, and analysis that are involved with in-line 

blending. See 40 CFR 80.65(f).

b. How Can We Establish the Accuracy of the Measurement System 

(All Qualified Methods/Installations) For Each Parameter?

We proposed grouping the gasoline and diesel fuel parameters that must be 

measured (e.g., aromatics, sulfur, etc.), into two categories, depending upon 

whether it is practically feasible to construct and use gravimetric standards501 for 

defining the parameter and thus, for determining the accuracy of a measurement 

method. To establish the accuracy of methods measuring each parameter for which 

gravimetric standards are not feasible, we proposed retaining an EPA-prescribed 

reference method or designated method that would, in effect, define the 

parameter—as in “parameter X is, for federal regulatory purposes, whatever method 

Z measures.” We explained that parameters that require such treatment would be 

described as “method-defined” parameters. We also explained that anchoring the 

accuracy of a method intended to measure such a parameter would be accomplished 

by relating its measurements on a particular set of test fuels to measurements made 

on the same fuels by a laboratory operating the designated method. We further 

explained that this approach is often referred to as “correlating” the new method 

 

500

 For some parameters the criteria will be based on the laboratory’s chosen method’s ability to 

closely predict the measurements made by EPA’s chosen or “designated” method. This approach is 

made necessary by the “method-dependent” definition of some of the parameters to be measured.

501 Gravimetric standards are test materials made by adding a carefully weighed (hence 

“gravimetric”) quantity of the analyte of interest to a measured quantity of another substance known 

not to contain any of the analyte. The result is a solution with a very accurately known 

concentration of the analyte. The accuracy of gravimetric standard reference materials can be 

closely controlled and is not dependent on an analytical test method. 
Page 409 of 529

with the designated method. Such a correlative approach to qualification is 

dependent for its workability upon the test fuels used to establish the correlation. 

They must be sufficiently varied along all important dimensions so that day-to-day

production laboratory operations are very unlikely to turn up some unusual fuels (or 

a new class of fuels produced, say, by some new refining process) for which the 

correlation equation derived earlier does not hold true and where the predictions of 

the designated method’s results are quite erratic and inaccurate.

As also explained at proposal, our classification of parameters into the 

absolute or method-defined categories is not entirely straightforward. Of the 

parameters subject to our proposal, only those with sulfur as the analyte seem to fall 

unambiguously into the absolute category. We additionally explained that sulfur is a 

single element rather than a compound (or, worse, a class of compounds with 

numerous members) and thus lends itself to the construction of gravimetric 

standards. We further explained that the methods that are currently used to measure 

sulfur in gasoline and diesel fuel have been subject to intensive recent development 

work and are largely free of matrix effects. Sulfur in butane is, arguably, even more 

amenable to the absolute approach, since the matrix, butane, is a single compound 

rather than a constantly varying mixture of many compounds. We noted that the 

diesel sulfur rule used the absolute approach. We therefore proposed to treat 

gasoline sulfur and sulfur in butane as absolute parameters. For a complete 

discussion of our classification scheme see 78 FR 29955-29956.

Given logical and practical difficulties with using a gravimetric approach to 

qualifying methods for parameters other than sulfur, EPA proposed and sought 

comment on classification of parameters into either the absolute category to be used 

for sulfur or method defined or correlative category to be used for all parameters

other than sulfur. All comments received were in support of this approach. 

Therefore, today, EPA is adopting a classification of fuel parameters where the 

absolute category will be used for sulfur in gasoline and butane, and a method 

defined category will be used for all other gasoline and diesel fuel parameters.

c. How Would Analytic Methods be Evaluated for Qualification? 

i. General Provisions: To Which Methods and Which Parties do 

the Proposed Requirements Apply?

We proposed and requested comments on requiring laboratories to qualify

all methods used in measurements for regulatory purposes. We explained that EPA 

did not believe that a relatively simple qualification test would ensure continued 

measurement quality, but rather that these requirements would greatly reduce the 

likelihood of a laboratory undertaking important measurements without some 
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assurance that an instrument is in working order, that at least one operator502 in the 

laboratory understands the method for its use, and that it can be made to perform to 

meet acceptable criteria. We received comments that were supportive of these 

requirements.

ii. How Would Laboratories Demonstrate the Precision and 

Accuracy of Methods for Measuring “Absolute” Parameters and

Thus Qualify the Methods for Use?

As explained at proposal, test methods typically used for gasoline sulfur are 

also frequently used for diesel sulfur. We also noted that the ASTM test method 

designations for both are the same. At proposal, we explained that examination of 

test method descriptions, however, pointed toward substantial differences in how 

these test methods are used in the different matrices. Thus, while we considered the 

possibility of allowing the diesel sulfur qualifications to be used also for gasoline 

sulfur, we believed differences between a diesel fuel matrix and gasoline fuel 

matrix were likely too great to permit such a sweeping exemption from 

qualification requirements. We reasoned that reworking test methods to measure 

gasoline sulfur would, in many cases, generate most of the data needed for 

qualification, and thus would not represent a major additional effort. So, despite 

VCSB-sponsored gasoline sulfur test methods bearing the same organizational 

designations as their diesel counterparts, we proposed to require that these test 

methods qualify separately for use in measuring gasoline sulfur (78 FR 29956). No 

negative comments were received on our proposal to require test methods that have 

already been qualified for diesel fuel to qualify separately for gasoline. Thus, 

consistent with our proposal, we are finalizing requirements for test facilities that 

have already qualified a method for measuring sulfur in diesel fuel to qualify test 

methods for measuring sulfur in gasoline.

Operational Description: We proposed requiring applications for 

qualification to include a complete operational description of the test method in 

question. For methods published by organizations such as ASTM International, we

explained that the test method designation number and title would satisfy this 

requirement. We also proposed requiring the description to include the scope of the 

test method, a summary, discussion of interferences that are expected, apparatus 

needed, reagents, sampling and specimen preparation, calibration, test method 

procedure, calculations, and any test method-specific quality control (78 FR 29956). 

We received comments in support of these requirements as well as comments 

indicating that the regulations should explicitly state that the test method 

 

502 The intent behind the qualification process is to demonstrate the facility’s capability with the 

method. Accordingly we did not propose that each instrument used to implement a particular 

method be required to qualify (some labs may have several instruments implementing a single 

method) or that each operator be so required. We recommend, but did not propose to require, that a 

laboratory rotate operators during the testing required for qualification, thereby both improving and 

testing the skills of all operators for a given method and strengthening its quality program.
Page 411 of 529

designation number and title of the test method would meet the operational 

description requirement for VCSB test methods. The Agency agrees with this 

comment and has modified the final regulations as suggested. In today’s action we 

are also finalizing all other operational description requirements as proposed. 

Precision Qualification: We proposed and sought comments on 

requirements for precision qualification that were similar to requirements set forth 

in the non-road diesel sulfur rule. As explained at proposal that rule imposed a 

maximum value for the standard deviation503 of a series of at least 20 measurements 

over at least 20 days on a single fuel under site precision conditions. Specifically, 

the diesel rule used 1.5 times the repeatability standard deviation (ASTM “r”/2.77) 

of what was the least precise of the then-allowed methods. We explained that the 

factor of 1.5, expands the allowable variability from that of back-to-back tests (as in 

ASTM’s definition of repeatability) to account for the sources of greater variability

that find their way into a longer series of tests on the same material. We explained 

that in the qualification process for ultra-low sulfur diesel testing, the factor of 1.5 

proved to be neither so tight that most laboratories were unable to meet it, nor so 

loose as to not be challenging at all. Thus, we considered it to be reasonable, as 

well as having proven to be workable in practice, and therefore proposed that the 

precision qualification for diesel fuel be applied to both absolute and method 

defined fuel parameters.

Comments were supportive of our proposed precision criteria for the 

absolute fuel parameters of sulfur in gasoline and sulfur in butane. We also 

received comments that were against the extrapolation of precision qualification for 

absolute fuel parameters based on published method repeatability (r) to method 

defined parameters. These comments will be addressed in more detail below under 

the discussion of precision criterion for method defined fuel parameters.

Gasoline Sulfur Precision Criteria: We proposed and sought comments on 

the use of the repeatability for ASTM D7039-07 (i.e., 1.76 ppm at 10 ppm) to set 

the precision criterion for sulfur in gasoline. We reasoned that the maximum 

allowable standard deviation of the twenty test results on a 10 ppm gasoline would 

be 0.95 ppm504. We did not propose to prescribe the parameter level for the fuel 

used for these precision tests, because we believed that this maximum limit will 

vary depending upon the repeatability number that the ASTM D7039-07 test 

method’s repeatability formula yields, given the parameter value of the test fuel 

chosen. We also explained that if a laboratory selected a 5 ppm fuel to test instead 

 

503 Where the standard deviation is estimated from a sample of the population (formula uses “N-1” in 

the denominator).

504 This number was determined by using the repeatability equation for “r” from ASTM D7039-07 

for a 10 ppm sulfur gasoline to get 1.76 ppm, dividing the “r” in ppm by 2.77 to obtain the 

underlying standard deviation of 1.39 ppm, and multiplying the result by 1.5 (criterion used in diesel 

sulfur rule) to get 0.95 ppm.
Page 412 of 529

of a 10 ppm fuel, the maximum limit for the standard deviation would be 0.67 ppm

(78 FR 29956-29957). Comments provided were in support of this requirement. 

Thus the Agency is finalizing the precision criterion for sulfur in gasoline that is 

based on the repeatability of ASTM D7039-07. This would require dividing it by 

2.77 to obtain the underlying standard deviation, and multiplying the result by 1.5 

to get the applicable precision criterion based on the concentration of sulfur in 

gasoline.

Sulfur in Butane Precision Criteria: We proposed a precision criterion 

based on the repeatability of ASTM D6667-10. We explained that this test 

method’s repeatability at the 10 ppm level would be1.15 ppm, and that calculations 

for sulfur yielded an upper limit for the standard deviation of the 20 tests for sulfur 

in butane of 0.62 ppm (78 FR 29957). Most of the comments we received were in 

support of our proposal. We also received one comment from the Independent Fuel 

Terminal Operators Association (IFTOA), a trade association for fuel terminal 

operators, which provided comments on behalf of its members. IFTOA expressed 

concerns over the repeatability calculation we provided at proposal for 10 ppm 

sulfur in butane. IFTOA explained that reduced sulfur levels would inhibit butane 

blending due to reduced availability of butane with very low sulfur. IFTOA 

requested additional flexibility and noted the difficulty and expense involved in 

finding butane with sulfur content of 10 ppm or below. Therefore, IFTOA urged 

the Agency to consider focusing on the sulfur content of the final blend and not the 

sulfur content of the butane component. IFTOA further provided comments urging 

the Agency to allow blenders downstream of the refinery and importer gate to add 

butane that meets the downstream per gallon cap so long as the butane blending 

operation does not cause the blender’s finished gasoline to have annual average 

sulfur content above 10 ppm.

The Agency disagrees with IFTOA’s reading of the example calculation 

provided in the proposed preamble and regulations, which utilized the repeatability

of ASTM D6667-10 as the basis for the precision criterion when the sulfur level of 

butane was at 10 ppm. The intent of this example was not to provide a cap on 

sulfur in butane at 10 ppm, but rather only intended to be an example explaining 

that the precision criterion for sulfur in butane would be 0.62 ppm if the sulfur level 

in butane was 10 ppm. The Agency agrees with IFTOA that blenders downstream 

of the refinery and importer gate should be permitted to add butane that meets the 

downstream per gallon cap of 80 ppm so long as the butane blending operation does 

not cause the blender’s finished gasoline to have an annual average sulfur content 

above 10 ppm. Accordingly, today’s final regulations include examples if sulfur in 

butane is at the 80 ppm cap, instead of the 10 ppm sulfur average. We are also 

finalizing precision criteria for sulfur in butane that is based on the repeatability of 

ASTM D6777-10, consistent with our proposal.

Temporal Distribution of Precision Tests: With regard to spacing of the 

required 20 precision tests, we proposed and sought comments on requiring 7 or 

fewer tests per week and 2 or fewer tests per day. We also sought comments on the 

following two options: 1) a requirement that 23 or more hours must elapse between 
Page 413 of 529

tests (this option requires either testing on weekends or an extension of the 20 

days); and 2) tests arranged into no fewer than five batches of five or fewer tests 

each, with only one such batch allowed per day over 20 days (78 FR 29957). We 

received comments in support of option 2, (i.e., arranging tests into no fewer than 

five batches or fewer tests each, with only one such batch allowed per day over the 

minimum of 20 days) because, according to commenters, it would provide the most

flexibility and be easier to implement. Today’s rule includes requirements for 

testing that are consistent with our proposed option 2.

Accuracy Qualification: We proposed and sought comments on accuracy

criteria for absolute fuel parameters that are similar to the criteria for sulfur in diesel 

fuel. We proposed that applicants for qualification would be required to select two 

commercially available gravimetric standard reference materials (SRM), and then 

show that their laboratory and method are capable of getting an average of ten 

consecutive results that are very close to the Accepted Reference Value (ARV), for 

each SRM. We proposed to use 0.75 times the precision criterion described above, 

which is the same value for sulfur in diesel. We explained that in the case of 

gasoline sulfur, for a gravimetric standard with ARV = 10 ppm, this would be 0.75 

times 0.95 ppm or 0.71 ppm. The corresponding numbers for sulfur in butane at the 

10 ppm level would be 0.75 times 1.15 or 0.47 ppm. For other parameters that 

might eventually fall into the absolute category, we proposed that the precision and 

accuracy criteria would be determined as a function of the ASTM repeatability of 

one of the methods (selected by EPA) available for measuring that parameter (78 

FR 29957). 505 Comments were supportive of our proposed requirements for 

determining accuracy criteria for absolute fuel parameters. Thus, the Agency is 

finalizing the accuracy qualification criteria as proposed.

iii.How Would Laboratories Demonstrate The Precision and 

Accuracy of Methods for Measuring “Method-Defined” 

Parameters and Qualify the Methods for Use?

Operational Description: We proposed the same operational description 

requirements for both method defined and absolute parameters. We explained that

publication of a test method by a VCSB organization, such as ASTM, where the test 

method number and title is cited, would meet this criterion. We also explained that 

a non-VCSB test method would require additional information because non-VCSB 

 

505 It is important to understand that the numerical examples presented in the text are entirely 

hypothetical, because use of precision testing material or gravimetric standards at levels other than 

those used in the examples would change all of the numbers. Use of a gasoline sulfur gravimetric 

standard at 5 ppm (instead of the 10 ppm used in the example) would require computing the 

repeatability of the method at 5 ppm using the equation given in the method description, dividing it 

by 2.77, multiplying the result by 1.5, and then multiplying that result by 0.75. As a short-cut, the 

accuracy criterion could be determined by multiplying the ASTM repeatability of the method at the 

level in question by 0.4061.
Page 414 of 529

test methods have not been fully vetted by a VCSB. We explained that the 

underlying scientific measurement principles must be thoroughly explained and the 

apparatus described well enough that a trained outsider could successfully

implement the non-VCSB test method and replicate the applicant’s results (78 FR 

299957). In addition, for non-VCSB test method we proposed that the description 

must include the scope of the test method, a summary, discussion of any 

interferences that are expected, apparatus needed, reagents, sampling and specimen 

preparation, calibration, test method procedure, calculations, and any test methodspecific quality control. As previously discussed in Section VI.A.3.c.ii, we 

received comments in support of these requirements as well as comments indicating 

that the regulations should explicitly state that the test method designation number 

and title of the test method would meet the operational description requirement for 

VCSB test methods. The Agency agrees with this comment and has modified the 

final regulations as suggested. In today’s action we are also finalizing all other 

operational description requirements as proposed.

Precision Qualification Specifics: We proposed the same precision 

qualification criteria for both method defined and absolute parameters. For 

reference installations, we proposed additional requirements that the instrument 

must be shown to be in statistical control, as provided for in ASTM D6299-10e1

(and the proposed SQC procedures) and that the applicant must submit control 

charts showing a record of in-control operation for at least five months. At proposal 

we acknowledged that while these requirements would likely result in a delay

between instrument setup and the ability to qualify a reference installation, we 

believed that any delay was necessary to demonstrate the stability of these critically

important installations. We reasoned that EPA expected no lack of laboratories that 

are capable of meeting these standards considering the number of long-established 

installations of these designated test methods (78 FR 29957).

The Agency received several comments from the American Petroleum 

Institute, the Association of Fuel and Fuel Petrochemical Manufacturers, Chevron 

Products Company, and Marathon Petroleum Company LP that were against 

extrapolating the same precision qualification criteria for absolute fuel parameters, 

which is based on the published method’s repeatability (r), to the precision 

qualification criterion of method defined fuel parameters. Specifically, according to 

the commenters, precision criteria for method defined fuel parameters are sensitive 

to the matrix making up the fuel material that is to be analyzed. This degree of 

sensitivity to the fuel matrix is different for different test methods, techniques, and 

instrumentation that measure the same method defined fuel property. Commenters 

recommended instead that the precision standard deviation qualification criterion be 

based on the Test Performance Index (TPI), as described in ASTM D6792.506 The 

commenters further explained that the TPI in ASTM D6792 sets minimum site 

 

506 ASTM D6792-07, entitled, “Standard Practice for Quality System in Petroleum Products and 

Lubricants Testing Laboratories”.
Page 415 of 529

precision performance criteria based on test method reproducibility (R) and the 

Precision Ratio (PR) of the published test method. Also, commenters noted that 

using the TPI as outlined ASTM D6792 would be consistent with OMB Circular 

119, which directs agencies to use voluntary consensus standards in lieu of 

government unique standard except where inconsistent with law or otherwise 

impractical.

The Agency has evaluated ASTM D6792 and agrees that it would be 

appropriate to base the precision qualification criterion for method defined 

parameters on the TPI as described in ASTM D6792. We also agree that methoddefined test methods are subject to fuel matrix effects, and therefore, that the degree 

of sensitivity to the fuel matrix is different for different test methods, techniques, 

and instrumentation that measure the same method defined fuel property. 

Therefore, in a change from proposal, and in response to comments, we are 

requiring that the precision qualification criterion for method defined parameters be 

based on the Test Performance Index (TPI) as described in ASTM D6792.

Olefins in Gasoline Criterion: We had proposed to base the precision 

qualification for olefins in gasoline on the repeatability of ASTM D1319-10. Thus, 

we explained that for a test fuel with olefins at, say, 9 volume percent (Vol.%), the 

repeatability would be 0.972, the underlying standard deviation would be

0.972/2.77=0.351, and the precision criterion would be 1.5 times that or 0.53 

Vol.%. We had proposed that a laboratory’s standard deviation for the 20 tests 

could not exceed that value and still qualify for precision (78 FR 29957-58). 

Several commenters including the American Petroleum Institute, the Association of 

Fuel and Fuel Petrochemical Manufacturers, Chevron Products Company, and 

Marathon Petroleum Company LP, argued that that the precision standard deviation 

criterion for method-defined parameters should be based on the TPI described in 

ASTM D6792-07.507 Also, both API and AFPM stated that using the TPI as 

outlined in ASTM D6792 is consistent with OMB Circular 119, which directs 

agencies to use voluntary consensus standards in lieu of government unique 

standards except where either inconsistent with law or otherwise impractical.

As previously explained, the Agency has evaluated and agrees with the 

comment that the TPI, in ASTM D6792, should be used because it sets minimum 

site precision performance criteria based on test method reproducibility (R) and the 

Precision Ratio (PR) of the published test method. The Agency is therefore, 

finalizing the requirement that precision criteria for olefins in gasoline will be based 

on the TPI in ASTM D6792. Additionally, consistent with our proposal to afford 

the regulated community the use of the most current version of test methods, we are 

also updating the olefin in gasoline test method ASTM D1319 to the 2013 year 

version, as discussed in Section VI.A.1.a.iii above. We are also finalizing 

 

507 ASTM D6792-07, Standard Practice for Quality System in Petroleum Products and Lubricants 

Testing Laboratories1.
Page 416 of 529

requirements that the reproducibility of ASTM D1319-13 be utilized in setting the 

precision criterion. For example, the reproducibility is 3.06, and the precision 

criterion is 0.3 times 3.06 or 0.92 volume percent (Vol. %), for a test fuel with 

olefins at 9 Vol. %.

Table VI-4 provides the TPI in ASTM D6792 for setting the olefin 

precision criterion.

Table VI-4 Method-Defined Precision Criterion for Olefins in Gasoline

ASTM 

Method

Property Precision 

Ratio (R/r)

ASTM 

D6792 

minimum 

TPI = (r/R’)

Maximum 

acceptable 

site 

precision 

(R’)

Site 

Precision 

Standard 

Deviation 

Qualification 

= R’/2.77

D1319-13 Olefins 3.2 1.2 0.83R 0.3R

Aromatics in Gasoline Criterion: We proposed use of the repeatability 

standard deviation for D1319-10 to set the precision criteria for aromatics in 

gasoline (78 FR 29958). As previously explained, in response to comments 

received on proposed requirements for precision criteria for method-defined 

parameters, such as olefins in gasoline, the Agency is finalizing regulations for the 

use of the TPI in ASTM D6792 because we believe that it sets minimum site 

precision performance criteria based on test method reproducibility (R) and the 

Precision Ratio (PR) of the published test method. Additionally, as also previously

explained, consistent with our proposal to afford the regulated community the use 

of the most current version of test methods, we are updating the aromatic in 

gasoline test method ASTM D1319 to the 2013 year version, as discussed in 

Section VI.A.1.a.iii. Thus, the reproducibility of ASTM D1319-13 should be 

utilized in setting the precision criterion. In today’s action, the Agency is finalizing 

precision criteria for aromatics in gasoline that is based on the TPI in ASTM D6792 

TPI. Thus, for example, the reproducibility is 3.7, and the precision criterion is 0.3

times 3.7 or 1.11 Vol. % for a test fuel with aromatics at 32 Vol. %.

Table VI-5 provides the TPI in ASTM D6792 TPI for setting the aromatics 

precision criterion along with the use of ASTM D1319-13’s reproducibility.

Table VI-5 Method-Defined Precision Criterion for Aromatics in 

Gasoline

ASTM 

Method

Property Precision 

Ratio (R/r)

ASTM 

D6792 

Maximum 

acceptable 

Site 

Precision 
Page 417 of 529

minimum 

TPI = 

(r/R’)

site 

precision 

(R’)

Standard 

Deviation 

Qualification 

= R’/2.77

D1319-13 Aromatics 2.8 1.2 0.83R 0.3R

Oxygen and Oxygenates in Gasoline Criterion: We proposed use of the 

repeatability for D5599-00 (2010) to determine the precision criterion for oxygen 

and oxygenates in gasoline. We explained that for a test gasoline with 3 mass% 

total oxygen, the repeatability would be 0.083 mass% and the criterion for precision 

in this example to be 0.045 mass% (78 FR 29958). As previously explained, in 

response to comments we received on our proposed precision criteria for methoddefined parameters, the Agency is finalizing the use of the TPI in ASTM D6792 for 

setting precision criteria for method defined parameters. Thus, for a test fuel with 

total oxygenate content at 3 mass % total oxygen, the reproducibility would be 0.32, 

and the precision criterion is 0.3 times 0.32 or 0.10 mass % total oxygen. Table 

VI-6 provides the TPI in D6792for setting oxygen and oxygenates precision 

criterion.

Table VI-6 Method-Defined Precision Criterion for Oxygenates in 

Gasoline

ASTM 

Method Property

Precision 

Ratio 

(R/r)

ASTM 

D6792 

minimum 

TPI = 

(r/R’)

Maximum 

acceptable 

site 

precision 

(R’)

Site 

Precision 

Standard 

Deviation 

Qualification 

= R’/2.77

D5599—

00 (2010) Oxygenates 6.8 2.4 0.42R 0.15R

For each method defined fuel parameter that lacked alternative test methods 

we proposed a precision criterion of 1.5 times the repeatability for the designated 

test method divided by 2.77. We had proposed that a laboratory’s standard 

deviation for the 20 tests could not exceed that value and still qualify for precision

(Table VI-6, 78 FR 29958). As explained above, as it relates to the Agency’s 

response to the proposed precision criterion for method defined fuel parameters, the 

Agency today is finalizing precision criterion as provided in Table VI-7 for the 

various method defined fuel parameters lacking alternatives to the designated test 

method using the ASTM D6792 TPI approach, except for distillation. The 

distillation method defined fuel parameter is discussed in further detail below.

Table VI-7 Method-Defined Precision Criterion for Fuel Parameters lacking 

Alternatives to the Designated Test Method
Page 418 of 529

Test 

Method Property

Precision 

ratio (R/r)

ASTM 

D6792 

minimum 

TPI = 

(R/R’)

Maximum 

acceptable 

site 

precision 

(R’)

Site 

Precision 

Standard 

Deviation 

Qualification 

= R’/2.77

D5191-12 RVP 1.9 1.2 0.83R 0.3R

D3606-10 Benzene 4.6 2.4 0.42R 0.15R

D1319-13 Aromatics 

in Diesel 2.8 1.2 0/83R 0.3R

With regard to distillation properties, (which is one of the parameters 

lacking alternatives to designated test methods), several commenters, including API 

and AFPM, recommended the use of ASTM D86-07 for setting the precision 

criterion for distillation properties. According to these commenters, the precision 

criterion as published in later year versions of ASTM D86 is not consistently

supportable by actual ASTM ILCC program data. As support, they referenced Note 

31 of the current ASTM D86 test method.508 They commented that a plausible 

explanation for this is that the interlaboratory study (ILS) used to derive the current 

precision criteria required several runs on the ILS material to select heating profile, 

and hence does not reflect how the method is actually conducted in a routine 

production environment. In addition, the ILS study sample set may not adequately

cover the range of available real world production gasoline. They also stated that 

there is general consensus that the precision of this test method is sensitive to the 

slope of the boiling curve; hence, a constant precision as articulated in the cited 

ASTM D86-11, a method may not be appropriate as a one-size-fits-all measure for 

gasolines with different matrices and volatility properties for winter as compared to 

summer fuels. According to commenters, directionally, and based on on-going 

discussions with ASTM, it would appear that the ASTM test method precision may

revert to a boiling curve slope based approach, similar to ASTM D86-07. They

further commented that for gasoline containing ten volume percent ethanol (E10), 

the boiling curve slope and hence precision is impacted by the location of the 

azeotrope point relative to the distillation points of interest (T10, T50 and T90).509 

Both API and AFPM also commented that the precision function as stated in ASTM 

D86-07 is a more realistic representation for E-10 gasoline precision with different 

fuel matrices. Finally, API and AFPM expressed concerns on the use of ASTM 

D86-11a precision criteria and the proposed precision qualification of 1.5r/2.77, 

 

508 Note 31 of the current ASTM D86 test method reads “NOTE 31– A new inter laboratory study is 

being planned to address concerns that laboratories are not able to meet the precision for percent 

evaporated temperature at fifty percent.”

509 The azeotrope point is a function of the base stock gasoline composition, and therefore can vary 

with different fuel matrices.
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which they described as too restrictive. Both API and AFRPM provided fuel 

producer control chart data as an example, which is reproduced in Table VI-10.510

Table VI-8: API & AFPM Example of ASTM D86-11a Fuel Producer Control 

Chart Data

IBP E10 E50 E90 FBP

Avg F 103.65 151.32 224.88 351.44 417.16

Stdev F 1.93 1.66 1.36 1.22 2.66

Avg C 39.81 66.29 107.16 177.47 213.98

StDev C 1.07 0.92 0.75 0.68 1.48

EPA 

precision 

criteria

1.54 0.72 0.40 0.97 1.80

After reviewing these comments and especially data set out in Table VI-8, 

we agree that our proposed distillation precision criterion would likely be too 

restrictive, especially for the distillation point of E50. Accordingly, in a change 

from proposal and in response to these comments and additional data, the Agency is 

finalizing precision criterion for the gasoline distillation parameter based on 0.3 

times the automated reproducibility of ASTM D86-07 instead of ASTM D86-11a. 

Table VI-9 provides the precision criterion for the gasoline distillation method 

defined fuel parameter.

Table VI-9 Method-Defined Precision Criterion for Gasoline Distillation 

based on 0.3 times the Automated Reproducibility of ASTM D86-07

Percent Evaporated Point 0.3* Reproducibility (0C)

Initial Boiling Point 0.3 * 8.5 

10 Percent Evaporated 0.3 *(3.0 +2.64*Sc)

50 Percent Evaporated 0.3*(2.9+3.97*Sc)

90 Percent Evaporated 0.3*(2.0+2.53*Sc)

Final Boiling Point 0.3*10.5

Where Sc is the average slope (or rate 

change) of the gasoline distillation curve 

as calculated in accordance with Section 

13.5 of ASTM D86-07

 

510 The raw data supporting the control data is supplied by API and AFPM in docket EPA-HQ-OAR2011-0135.
Page 420 of 529

Accuracy Qualification: At proposal, we also explained that test methods 

used to measure method-defined parameters would likely fall into three separate 

tracks: reference installations of designated methods intended for use in qualifying 

alternative methods; designated method installations intended for ordinary

production measurements; and non-designated methods. We proposed and sought 

comments on requirements that reference instruments must be shown to have been 

near the middle of the distribution of the industry monthly inter-laboratory

crosscheck program (ILCC) for at least five months prior to application. We also 

proposed that laboratories would specifically compute the difference between the 

instrument's average measurement of the fuel closest to the applicable standards (or 

to the average value for the fuel type in the complex model) and the robust mean for 

that fuel obtained by all of the non-outlier labs in the program. We further 

proposed that this difference would be standardized by expressing it in robust 

standard deviation units. These standardized ILCC differences would be put into a 

moving average with a span of, say, 5 months. We proposed to set the standard so

that the instrument's moving average would be within the central 50% of the 

distribution of participating designated method labs. We also reasoned that because

a robust standard deviation is used by the ILCC program this percentage will have 

to be approximate (78 FR 29958).

Several commenters, including API and AFPM commented on the proposed 

requirements for reference installations of method defined fuel parameters used to 

qualify other method defined test methods. These comments and our response to 

these comments are discussed in further detail below.

At proposal we discussed the role of Voluntary Consensus Bodies in 

qualifying alternative analytical test methods as well as the use of reference 

materials in qualifying and maintaining such test methods. We requested comments 

on the appropriateness of using three types of standard reference materials for 

accuracy and on their applicability in the qualification process and statistical quality

control process of analytical test methods. Specifically, we proposed use of the 

following: 1) Gravimetric standards, 2) Consensus named fuels (e.g., gasoline or 

diesel fuels), and 3) Locally named standards. For a complete discussion of these 

issues see 78 FR 29958-29960. All comments received were in support of the use 

of these kinds of reference materials in the qualification process and statistical 

control program.

d. Qualification Criteria for Designated Method Installations Used 

to Qualify Method-Defined Parameter Instruments.

We proposed the following requirements for designated test method 

installations (also known as are reference installations) that would be used to 

qualify method-defined parameter instruments. We explained that these reference 

installations would be used to evaluate the accuracy of other alternative test 

methods and to establish correlation equations, and as such that we believed that 

they should be held to higher standards.
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First, we proposed that reference instruments must meet precision 

qualification requirements that are similar to the criteria set forth in the non-road 

diesel sulfur rule. As explained earlier, that rule imposed a maximum value for the 

standard deviation511 of a series of at least 20 measurements over at least 20 days on 

a single fuel under site precision conditions. Specifically, the diesel rule used 1.5 

times the repeatability standard deviation (ASTM “r”/2.77) of what was the least 

precise of the then-allowed methods. We proposed that for those method-defined 

parameters, shown in Table VI-6 of the proposed preamble, lacking currently

allowed alternatives to their designated methods, the precision criteria would be

based on the fuel parameter’s designated test method. At proposal, we also 

explained that in each case the precision criterion is determined by (“r”/2.77) times

1.5 where “r” is the ASTM repeatability determined for the particular fuel that is 

being used for the purpose of demonstrating the test method’s precision (79 FR 

29960).

As previously discussed, the Agency received comments that were not in 

support of extrapolating the same precision qualification criteria for absolute fuel 

parameters, which is based on published method repeatability (r) of the applicable 

fuel parameter times 1.5 and dividing by 2.77, to precision criterion of method 

defined parameters. As previously explained, these commenters stated that the 

precision criteria of method defined parameters are sensitive to the matrix of the 

fuel. This degree of sensitivity to fuel matrix effects is different for different test 

methods, techniques, and instrumentation that claim to measure the same method 

defined fuel property. Also, commenters recommended that the precision standard 

deviation qualification criterion for method defined parameters be based on a TPI as 

described in ASTM D6792.512 As previously explained, the Agency has evaluated 

ASTM D6792 and agrees that the precision qualification criterion for method 

defined parameters be based on a TPI as described in ASTM D6792. Thus, in a 

change from proposal, we are finalizing requirements for reference instruments to 

meet precision qualification requirements as discussed above for their respective 

fuel parameter in Table VI-4 through Table VI-9 of this preamble.

Second, we proposed that reference instruments must be shown to be near 

the middle of the distribution of the ILCC program for at least the five months prior 

to application.513 We proposed requiring laboratories to specifically compute the 

difference between the instrument's average measurement of the fuel closest to the 

applicable standards (or to the average value for the fuel type in the complex 

model) and the robust mean for that fuel obtained by all of the non-outlier labs in 

 

511 Where the standard deviation is estimated from a sample of the population (formula uses “N-1” in 

the denominator).

512 ASTM D6792-07, entitled, “Standard Practice for Quality System in Petroleum Products and 

Lubricants Testing Laboratories”.

513 There may be an alternative to this measure to be had from the D6299-10e1 calculations, so that 

we could require that the instrument be doing SQC and having a certain quality of performance. 

This could reduce the burden of calculations and align this requirement better with the NTTAA.
Page 422 of 529

the program. We further proposed that this difference be standardized by

expressing it in robust standard deviation units. We also proposed that these 

standardized ILCC differences would be put into a moving average with a span of, 

say, 5 months. We proposed to set the standard such that the instrument's moving 

average would be within the central 50% of the distribution of participating 

designated method labs. We explained that because a robust standard deviation is 

used by the ILCC program this percentage would have to be approximate. We 

further explained that such lab-specific qualification would be outside of the normal 

qualification of a lab for making regulatory measurements for certifying fuel and 

would pertain only to use of the instrument in certifying other methods. In essence, 

these designated method installations would serve as surrogates for the gravimetric 

standards that cannot be used in qualifying alternative methods for method-defined 

parameters (79 FR 29960).

Both API and AFPM stated that this requirement would be feasible for a 

single entity wishing to qualify alternate test methods under ASTM D6708 by using 

a single reference installation; however, they described the requirement as overly

restrictive in other instances. Based on a workup, provided as a separate attachment 

to their comments514, of the proposed requirements using ASTM D5599 Total 

Oxygen results on eleven RFG distributions, RFG1205 through RFG1303, they 

showed that less than fifteen percent of the participants met the proposed EPA 

requirement of staying within the central 50 percent for 5 successive exchanges. 

Therefore, they suggested a requirement of 3 out of 5 successive exchanges staying 

within the middle 50 percent of the distribution of measurements on the ILCC 

program would be more realistically achieved in practice. After reviewing these 

comments and data, the Agency agrees that setting a requirement of 3 out of 5 

successive exchanges to stay within the middle 50% of the distribution of 

measurements of the industry monthly ILCC program for at least five months is 

more appropriate and achievable as compared to 5 out of 5 successive exchanges 

staying within the middle 50% of the distribution of measurements of the ILCC for 

at least five months. Another commenter recommended the option of using other 

crosscheck programs besides those from ASTM, and suggested that EPA revise 

criteria for the reference installations at 40 CFR 80.47(k)(2) to also refer to use of 

commercially available monthly ILCC. The Agency agrees that the regulated 

community should be able to use both commercially available and industry monthly

ILCC, and has made this change to 40 CFR 80.47(k) to afford this flexibility. 

Therefore, in a change from proposal, and in response to these comments, the 

Agency is setting a requirement that a reference installation of the designated test 

method must be shown to be within the middle 50% of the distribution of 

measurements for 3 out of 5 exchanges of either the industry or commercially

available monthly ILCC program for at least five months.

 

514 For a description of workup and spreadsheet associated with these comments, see attachment No. 

4 in Docket number EPA-HQ-OAR-2011-0135-4276-A5.pdf and attachment No. 5 in EPA-HQOAR-2011-0135-4276-A6.pdf.
Page 423 of 529

Another commenter suggested that EPA should require applicants to submit

control charts showing a record of in-control operation for at least five months 

provided that: 1) regular maintenance and/or re-calibration conducted during the 5 

month in-control qualification period is considered as part of in-control normal 

operation, and 2) the clock for the 5 month period does not re-start (in other words 

the system is still considered to be in-control) if an assignable cause for out of 

control is found, mitigated, and the system is brought back in-control during the 

period that the reference installation is attempting to meet the 5 month in-statisticalcontrol requirement. The Agency agrees with these two conditions and in a change 

from our proposal, we are finalizing regulations that would allow systems meeting 

these two conditions to be in-control with respect to the 5 month in-statisticalcontrol requirement. Finally, for reference installations, we proposed that the 

reference instrument must be shown to be in statistical control, as provided for in 

ASTM D6299-10e1, comply with applicable SQC procedures as well as have

control charts showing a record of in-control operation for at least five months. We 

explained that while these requirements would likely impose a delay between 

instrument setup and the ability to qualify as a reference installation we believed

that any delay would be necessary to demonstrate the stability of these critically

important installations. We also reasoned that we expected no lack of facilities 

capable of meeting these standards considering the number of long-established 

installations of these designated methods. 

API and AFPM disagreed with this requirement and stated that summary

statistics (mean and standard error = standard deviation / square root [no. of 

results]) from ILCC program data can be used as is, i.e., without imposing the 

reference installation criteria to conduct an ASTM D6708 assessment on VCSB 

alternate test methods, provided that the number of non-outlying results is greater 

than 16 for both designated and alternate methods. According to both commenters, 

this is the current de facto methodology for determination of ARV of check 

standards as specified in ASTM D6299, clause 6.2.2.1 and Note 7. Both 

commenters also suggested that using ASTM D6299 for establishing ARV would 

be consistent with OMB Circular 119. They noted also that ASTM ILCC program 

data for the method-defined parameters of interest exceeds this number (16) 

significantly.

API and AFPM also commented that it is neither necessary nor statistically 

justified to apply the reference installation precision and middle 50 percent criteria 

to the ILCC program data for designated test method because the relevant ILCC 

program statistics are calculated using outlier-free data, and the number of data 

points is large, hence providing a better statistical sample of the laboratory

population. According to them, the mean calculated using the full ILCC program 

outlier-free data set is a more accurate representation of the population parameter 

(μ) than the mean calculated using only the middle 50 percent. They noted the 

standard error for the arithmetic mean calculated using the full ILCC program data 

set is significantly reduced due to the square root [number of non-outlying results] 

term in the denominator for calculation of standard error. Both API and AFPM also 
Page 424 of 529

urged EPA to clearly state that the use of ILCC program data as described above is 

suitable for an ASTM D6708 assessment of VCSB alternate test methods. EPA 

agrees that the use of ASTM ILCC program data is suitable for an ASTM D6708 

assessment of VCSB alternative test methods, provided that the number of nonoutlying results is greater than 16 for both designated and alternate methods. In 

these situations where VCSB ILCP data is utilized during an ASTM D6708 

assessment, the reference installation criteria provided in the regulations will not 

apply, rather a VCSB will have the flexibility of utilizing the VCSB ILCC program 

data to conduct an ASTM D6708 assessment. The Agency has made these changes 

in the final regulations to reflect these comments.

Finally, API and AFPM noted that the current “robust” outlier treatment 

methodology for the ASTM CS92 ILCP program will be replaced with a 

statistically more rigorous approach using the Generalized Extreme Studentized 

Deviation (GESD) technique. Thus, they suggested that EPA remove the term 

“robust” from the preamble and regulations wording. EPA agrees with the 

comment and has removed “robust” from the final regulations wording. 

e. Qualification Criteria for Designated Test Method Installations 

that are “Method-Defined” Parameters Instruments and Not Used to 

Qualify Other “Method-Defined” Methods

At proposal, we explained that refiners, importers and oxygenate blenders 

producing gasoline and diesel fuel are required to test these fuels to determine the 

levels of various specified parameters. A designated test method is associated with 

each parameter to be tested (except for sulfur concentration in ultra-low sulfur 

diesel fuel, which must meet performance-based requirements515) in 40 CFR part 

80. Table VI-5 of the proposed rule preamble listed the fuel parameters and their 

corresponding designated test methods. We proposed that installations of 

designated methods must maintain records and meet certain statistical quality

control requirements. We explained that requiring all installations of all methods, 

including existing designated method installations, to implement statistical quality

control, would likely suffice to homogenize and improve measurement quality in 

these already-stable and standardized methods (78 FR 29961).

f. Qualification Criteria for Method Defined Parameter Instruments 

Other Than Designated Test Methods

With regard to method-defined parameters, the Agency today is finalizing

two options for qualification of alternative test methods. The first option, known as 

the VCSB approach, allows for qualifying methods that have been sponsored and 

published by a voluntary consensus standards body, such as ASTM International. 

The second option, known as the non-VCSB approach, involves qualification for a 

 

515 See 40 CFR 80.580, 40 CFR 80.584 and 40 CFR 80.585.
Page 425 of 529

laboratory that has developed its own analytical test method but has decided not to 

offer it for evaluation and establishment through a VCSB-based organizational 

process. At proposal, we explained that both options would require the candidate 

method to have a precision criterion that is at least equal to that of the designated 

analytical test method (though not defined in precisely the same way). We also 

proposed to require that the alternative method must also be capable of close 

correlation with the designated method for the parameter such that the refiner may

use the alternative method results to produce predicted designated method results 

that it can subsequently use in demonstrating compliance with the applicable fuel 

composition or performance standards (78 FR 29961).

Consistent with our proposal, we are finalizing the following criteria for 

both the VCSB and non-VCSB approaches to qualify method-defined instruments

that are discussed in further detail below.

i. Qualification Criteria for VCSB Method-Defined Parameter 

Test Methods

For methods that have been sponsored and published by a VCSB, such as 

ASTM, we expect that at a minimum, the VCSB must have fully described the 

analytical test method, so that it is replicable in many different laboratories and its 

operation may be understood by a technician. (We continue to consider publication 

of a method by a VCSB organization such as ASTM as meeting this criterion.) The 

VCSB must have tested the candidate method in a round robin program against the 

designated method, must have published a determination that the method meets the 

criteria specified in the discussion below, and must have published the information 

necessary to correlate the alternative method to the designated method. Consistent 

with our proposal, a VCSB-based candidate alternative analytical test method need 

not be qualified separately in each laboratory that adopts it. This is because by the 

time such a test method has been through the extensive development process 

typically required by a VCSB, the method’s procedures would have been 

exhaustively described. At this point there will be little uncertainty about how the 

analytical test method is to be applied, and it will have been implemented in a 

variety of different laboratories and used on a variety of different types of fuels. 

Therefore, we continue to believe that the VCSB-based process gives EPA some 

confidence that the analytical test method is likely to be stable in use and can be 

implemented with very little ambiguity regarding instrumentation, materials, and 

procedures. Moreover, VCSB method evaluation protocols have been established; 

including a protocol for comparing methods provide means for establishing a VCSB 

alternative method’s precision parity with the designated method for the parameter 

and for determining whether the alternative method can be adequately correlated 
Page 426 of 529

with the designated method.516 Further, consistent with our proposal, VCSB 

method-defined test methods must utilize ASTM D6708 to determine if a 

correlation equation is necessary.

ii. Qualification Criteria for non-VCSB Method-Defined 

Parameter Test Methods

Consistent with our proposal, a candidate method that follows the nonVCSB-based route for qualification must be qualified independently by each 

analytical laboratory that wishes to adopt the method. We proposed the following 

seven qualification criteria for non-VCSB method-defined parameter test methods.

First, the Agency proposed to require a complete operational description of 

the non-VCSB test method, as described above in Section VI.A.2.c.iii of this 

preamble. We explained that the operational description must be thorough enough 

that a person lacking expertise in the operation of the test instrument would be able 

to replicate its results.

Second, the Agency proposed that the candidate non-VCSB test method be 

tested on a range of fuels517 and by a qualified reference installation of the 

applicable designated test method.

Third, the Agency proposed that the specific laboratory using the candidate 

non-VCSB test method must statistically establish through application of ASTM 

D6708-08 that the candidate method measures the same aspect of samples as the 

applicable designated test method.

Fourth, the Agency proposed to disqualify non-VCSB test methods with 

important sample-specific biases (matrix effects) that cannot be considered as 

random as determined by ASTM D6708-08. We explained that it was possible that 

a non-VCSB test method suspected by the applicant of being highly matrixsensitive may be qualified on a narrowly circumscribed range of fuels (which must, 

meet the D6708 statistical variability criteria). In this situation, types of fuels used 

for qualification and the method that is to be approved must be specified in the 

method description. Fuels outside of this scope would have to be analyzed for 

regulatory purposes by some other method. The Agency believes that any 

restriction on the scope of fuels to be used in qualifying a method must be 

accompanied by a discussion of how the applicant plans to screen samples for 

conformity to the scope.

 

516 ASTM D 6708-08, entitled, Standard Practice for Statistical Assessment and Improvement of 

Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a 

Material.

517 Fuels, either consensus named fuels or locally named reference materials, used must be typical of 

those to be analyzed by the facility in practice and must meet the data requirements (variability, etc.) 

of ASTM D6708-08.
Page 427 of 529

Fifth, the Agency proposed that precision qualification be conducted in the 

form of cross-method reproducibility of the candidate and applicable designated test 

method, where the “cross-method reproducibility” must be equal to or less than 70 

percent of the published reproducibility of the applicable designated test method.

We explained that the Agency believes that when ASTM D6708-08 is used 

in this manner (without joint round robin data) the cross-method reproducibility

(Rcm) output by the program is not really a reproducibility in the usual sense, but 

rather indicates the expected value with uncertainty of the differences between the 

designated method and qualification candidate method. We believe that when used 

this way, Rcm from ASTM D6708-08 is more analogous to a site precision than to 

an inter-laboratory reproducibility. For a detailed description of cross-method 

reproducibility (Rcm) see 78 FR 29962.

Sixth, the Agency proposed that the applicant would demonstrate, through 

the use of ASTM D6708-08, whether a correlation to the designated test method is 

necessary. We explained that ASTM D6708-08 could also be used to determine 

whether the candidate methods results are either null compared to the designated 

test method and thus, needs no adjustment or correlation, or whether some 

correction or correlation equation is required so the candidate method may predict 

designated method results. We proposed the use of ASTM 6708-08 for corrections, 

if it is determined that the candidate method requires such a correction to predict 

designated test method results. The Agency proposed that the correction would be 

applied to the candidate instruments output to obtain measurements results for 

regulatory purposes.

Finally, we proposed to require that applicants for non-VCSB test methods 

secure an independent third party oversight and audit review of the data generated 

and used to qualify non-VCSB test methods. We proposed that the independent 

third party would provide an overall assessment of the analytical technique and 

methodology and discuss any limitations in the scope of the method, as well as 

attest that all requirements for non-VCSB test method qualification have been 

satisfied. The Agency explained that this requirement would provide additional 

assurance that a non-VCSB test method is found to be adequate in use for 

compliance (78 FR 29961-29962).

We received comments in support of the proposed qualification criterion for 

non-VCSB Method-Defined Parameters. One commenter recommended allowing 

third-party oversight service providers that have good working knowledge of 

ASTM D6708 and ASTM D6299 in addition to degrees in Chemistry or Statistics. 

Further, they believed that limiting the third party oversight qualification to only

U.S. degree holders would exclude non-U.S. degreed subject matter experts with 

equivalent knowledge and qualification. They suggested that rule language be 

expanded to include non-U.S. equivalent degreed or industry recognized subject 

matter experts. Another commenter recommended professional chemical engineers 

with demonstrated experience in analytical techniques as an option to chemists and 

statisticians because, according to the commenter, chemical engineers have a strong 
Page 428 of 529

background in chemistry, and based on trends within industry they would also have 

experience in statistical process control. The Agency agrees with these comments 

and has amended the final regulations to include chemical engineers and non-U.S.

degreed subject matter experts with equivalent knowledge and qualifications as 

third party oversight service providers. Rule revisions have also been made to 

reflect the recommendation that all of these candidates should also have a good 

working knowledge of ASTM D6708 and ASTM D6299.

Consistent with our proposal, the Agency today is finalizing the 

qualification criteria for non-VCSB method defined fuel parameters with the few 

changes in response to comments as discussed above.

g. Statistical Quality Control: How Can We Ensure that Test 

Methods Continue to Deliver Quality Measurement in Practice?

Today’s final action also includes a statistical quality control (SQC) 

program that must be applied to any analytical test method used in the regulatory

programs covered by this final action. Consistent with our proposal, every

laboratory that uses test instruments to measure fuel parameters to satisfy EPA’s 

reporting or recordkeeping requirements must implement and maintain a basic SQC 

program. Unlike the qualification criteria requirements, where only one set of 

essentially identical instruments implementing the same method in a laboratory

must qualify, every laboratory must have a separate SQC program for each 

instrument used to make measurements for reporting or recordkeeping purposes.518

Consistent with our proposal, we are also finalizing requirements that 

provide implementation of a SQC program by a laboratory as a defense in any

subsequent enforcement actions where measurements are in issue. Today’s 

requirements also reflect our proposal to adopt a subset of SQC procedures that are 

already widely in use from ASTM D6299-10e1. We continue to anticipate that the 

measures we are finalizing would not require the generation of much additional data 

by the laboratory that employs them and that the SQC program would improve the 

quality of measurement among those laboratories that adopt such measures. These 

SQC procedures used by laboratories would ensure that the test methods they have 

qualified and the instruments on which the methods are run yield results with 

appropriate accuracy and precision, e.g., that the results from a particular instrument 

does not drift over time to yield unacceptable values. The finalized minimum 

specific SQC requirements for laboratories for absolute parameters, VCSBapproved methods used to measure method-defined parameters, and non-VCSB 

 

518 Such SQC programs are already an established part of VCSB protocols for analytical laboratory 

operation (as indicated by such practices as ASTM’s D6299-10e1) and are likely to be part of most 

laboratories ”standard operating procedures.” Thus, such a requirement very likely adds little or 

nothing in the way of burden for most laboratories. Laboratories that lack such programs and would 

have to expend significant effort to create them are those most at risk for poor measurements and for 

which the effort is most easily justified.
Page 429 of 529

proprietary methods used to measure method-defined parameters are discussed in 

further detail below.

We proposed similar precision and accuracy SQC requirements for each 

instrument used to measure absolute and VCSB-approved and non-VCSB 

proprietary methods for measuring method-defined parameters in the laboratory. 

We proposed that every instrument would test a quality control (QC) material519

either once per 20 production tests or once per week and maintain both an “I” 

chart520 and an “MR” chart.

521

 We proposed that any violation of the control limit 

would be investigated by laboratory personnel, corrective action taken as required, 

and records kept of the incident for a period of 5 years. We also proposed allowing 

used of ASTM D6299-10e1 procedures for transitioning from one batch of QC 

material to another.

We also proposed use of Annex A1.9, entitled “Q-Procedure”, of ASTM 

D6299-10e1 for validating new QC material. We proposed that when QC material is 

soon-to-be-depleted, that a new batch of QC material would be prepared and its 

value compared to the old QC material on a chart. We explained that the new batch 

of QC material would be tested concurrently with the soon-to-be-depleted old QC 

material. And the results would be plotted from the “old” and “new” QC materials 

on respective charts, and if no special-cause signals are noted, then the result for the 

new material would be considered valid (78 FR 29963-64). 522

We received comments in support of all these requirements with the 

exception of requirements for both QC verification and validation of new QC 

materials. One commenter recommended that test facilities conduct verification of 

new QC material three times a year rather than on a quarterly basis so that this 

requirement is aligned with ASTM International ILCC program sample cycle 

frequency. The Agency agrees with this comment and has made rule language 

changes to reflect that test facilities can conduct verification of new QC material 

three times a year in order to align this requirement with ASTM ILCC program 

sample cycle frequency. Additionally, the Agency envisions this change will help 

encourage the participation of ASTM Subcommittees in the PBATM approach for 

their respective alternative test methods.

 

519 See ASTM D6299-10e1, paragraph 3.2.3 for a definition and Section 6 for guidance, selection, 

construction, handling, storage and use of reference material samples.

520 See ASTM D6299-10e1, section 7 and Section A1.5.1 for chart construction and usage, including 

criteria for deciding upon corrective action.

521 See ASTM D6299-10e1, Section A1.5.2 for chart construction and usage. Any exceedance of the 

control limit should be investigated.

522 See ASTM D6299-10e1, Annex A1.9 Q-Procedure. Procedures differ depending whether an Ichart, MR chart, EWMA chart, Q-chart or a combination of these charts are utilized by the 

laboratory.
Page 430 of 529

One commenter noted that the Q-procedure in ATSTM D6299, which 

relates to the handling of QC material batch transition, is intended to be an 

alternative approach to the concurrent testing (overlap) protocol. They suggested 

the option of using either one of the two procedures, and not both the Q-Procedure 

and I-procedure as we had proposed. According to the commenter, the Q-procedure 

is technically equivalent to the I-procedure. They also suggested that for sites 

opting to use the Q-procedure, the very first run on the new QC batch should be 

validated by either an overlap in-control result of the old batch, or by a single 

execution of an accompanying SRM. Then the new result would be considered 

validated if the single result of the SRM is within the established site precision (R’) 

of the ARV of the SRM. The Agency agrees that the Q-procedure is functionally

equivalent to the I-procedure and that laboratories should be given the flexibility to 

use either of these two procedures instead of both procedures, as proposed. The 

Agency also agrees that for sites opting to use the Q-procedure, the very first run on 

the new QC batch should be validated by either an overlap in-control result of the 

old batch, or by a single execution of an accompanying SRM. The new result 

would be considered validated if the single result of the SRM is within the 

established site precision (R’) of the ARV of the SRM. In response to these 

comments, we have revised our proposed regulations to reflect these suggested 

changes.

We proposed requiring every instrument to test a commercially available 

gravimetric “SRM” (“check standard” as defined in ASTM D6299-10e1) on a 

quarterly basis. We explained that the absolute difference between the mean of 

multiple back-to-back tests of the SRM and the ARV of the SRM that is greater 

than 0.75 times the published reproducibility of the test method must be 

investigated by laboratory personnel, appropriate action taken, and records kept of 

the incident and investigation. We proposed to require that records of the SRM 

measurements and investigations into any exceedance of these proposed criteria 

must be kept for a period of 5 years. Additionally, we proposed to require 

laboratories to pre-treat and assess results from the check standard testing after at 

least 15 testing occasions523, construct “MR” and “I” charts524 with control lines, 

and maintain control charts, logging, investigating, and correcting underlying 

causes of any control limit violations as discussed in ASTM D6299-10e1. We 

proposed to require that records of such incidents and the underlying control charts 

must be kept by the facility for a period of 5 years. (78 FR 29963.)

One commenter suggested that the expanded uncertainty of the ARV should 

be incorporated into the accuracy qualification criterion as follows: Accuracy

qualification criterion = square root [(0.75R)^2 + (0.75R)^2/L], where L = the 

 

523 See ASTM D6299-10e1, Section 8.2 (pretreatment) and Section 8.4 (assessment). Procedures 

differ depending upon whether a single check standard is used for multiple testing occasions or 

multiple check standards must be used.

524 See ASTM D6299-10e1, Section 8.4 and appropriate Annex sections for chart construction and 

guidance.
Page 431 of 529

number of single results obtained from different labs used to calculate the 

consensus ARV. According to the commenter, this is because the standard error of 

the ARV in the consensus-named fuels may not in all cases be negligible when 

compared to 0.75R. The Agency agrees with this comment and has incorporated 

the standard error of the ARV in the consensus-named fuel into the accuracy

qualification criteria for determining when appropriate action should be taken 

during an SQC investigation.

Today, the Agency is also finalizing the Statistical Quality Control 

requirements for absolute fuel parameters, and VCSB-approved and non-VCSB 

proprietary methods that are used for measuring method defined parameters, as 

proposed. Consistent with our proposal, the Agency is also finalizing requirements 

allowing use of either the “I” chart or Q-procedure for validation of new check 

standards, and the incorporation of the standard error of the ARV in the consensusnamed fuel into the accuracy qualification criteria for determining when appropriate 

action should be taken during an SQC investigation.

h. Agency Approval Options

We proposed to require qualification of only proprietary analytical test 

methods, i.e., non-VCSB test methods for fuel parameters. We also sought 

comment on whether we should require qualification of all analytical test methods 

for fuel parameters. The following section contains a discussion of our proposal, as 

well as our final decision based on the comments received on our proposal.

At proposal, we explained that the approach to performance-based 

qualification of test methods would go considerably beyond the minimum 

requirements of the National Technology Transfer and Advancement Act of 1995 in 

providing flexibility of method choice, and accomplish performance-based 

qualification without compromising measurement quality. We also reasoned that 

the primary tools for achieving the latter objective are laboratory-specific 

qualification of method installations and a requirement for across-the-board SQC. 

We also explained that while EPA would benefit from PBMS, when finalized, by

no longer having to evaluate new alternative measurement methodologies, this 

benefit would likely not offset the substantial and unpredictable resource costs 

involved in administering a qualification process and providing infrastructural 

support for laboratories’ SQC programs (78 FR 29964-65).

We proposed qualification requirements for only non-VCSB test methods 

for fuel parameters. We also proposed excluding designated test methods that have 

been in operation 6 months prior to finalizing this rule, as well as test methods that 

are developed by VCSBs, like ASTM International or the International 

Organization for Standards (ISO) from qualification requirements. We had also 

proposed subjecting laboratories that develop test methods but decide not to offer 
Page 432 of 529

them for evaluation and establishment through a VCSB-based organizational 

process to qualification requirements.525 We proposed that all test methods subject 

to qualification requirements must be qualified independently by each analytical 

laboratory that wishes to adopt the test method. We explained that this is because 

such a test method would not have been shown to be capable of accurately 

measuring the fuel parameter in different laboratories and across a variety of fuel 

matrices. We also explained that the precision for the candidate analytical test 

method must be established by a medium-term series of measurements on 

production fuels, the workability of the test method must be verified by at least on 

other laboratory, and its accuracy must be demonstrated by direct correlation to the 

designated analytical test method for the particular fuel parameter.

For test methods that have been sponsored and published by a VCSB such 

as ASTM or ISO, we proposed that the test method must be fully described so that 

it is replicable in many different laboratories and so that its operation may be 

understood by a technician. We also proposed that the VCSB must have tested the 

candidate test method in a round robin program against the designated test method, 

must have published a determination that the test method meets the performance 

criteria as discussed, and must have published the information necessary to 

correlate the alternative test method to the designated test method.526

We also proposed that a VSCB-based alternative test method need not be 

qualified separately in each laboratory that adopts it. We explained that this is 

because the test method’s procedures would have been exhaustively described by

the time the VCSB-based candidate alternative test method has been through the 

extensive development process typically required by a VCSB. We also reasoned 

that at this point there would be little uncertainly about how the analytical test 

method is to be applied, and it would have been implemented in a variety of 

different laboratories and used on a variety of different types of fuels. We continue 

to believe that the VCSB-based process gives some confidence that the analytical 

test method is likely to be stable in use and can be implemented with very little 

ambiguity regarding instrumentation, materials, and procedures. As also explained 

at proposal, VCSB method evaluation protocols have been established, including a 

recently developed protocol for comparing methods, which provide means for 

establishing a proposed VCSB alternative method’s precision parity with the 

 

525 Reasons for not submitting a local method for VCSB evaluation may include the proprietary 

nature of software or apparatus or the fact that the method is highly matrix-sensitive and not likely to 

perform consistently when used to analyze fuels with widely varying properties. EPA recognizes 

that matrix sensitivities may be subtle and methods with such characteristics may have been 

sponsored and published by VCSB’s.

526 This first approach assumes that a single such equation can be used for all labs using the method, 

an assumption that may not always hold true. The more detailed discussion of the two approaches 

that follow s this introduction explores this problem.
Page 433 of 529

designated method for the parameter527 and for determining whether the alternative 

test method can be adequately correlated with the designated test method.528

We also recognized that imposing qualification requirements on existing test 

methods developed by a VCSB without adequate lead time may be problematic. 

We thus proposed to give methods published and in operation upon publication of 

the Tier 3 proposed rule (May 21, 2013) a grace period of one year from the 

effective date of a final rule to comply with today’s requirements.

We also proposed to exempt existing (i.e., in use for six months prior to 

publication of the proposal) installations of designated test methods that are 

method-defined parameters from the qualification requirement. We reasoned that 

these installations were stable and capable methods in relatively experienced hands 

because they are already being used to certify fuels, and that requiring their 

qualification could be disruptive and burdensome to both their operators and to 

whomever manages the qualification process. We further reasoned that such 

installations would not benefit tangibly from this rule (as by obtaining access to a 

desired new method), but would nevertheless bear a newly-imposed burden.

We also proposed record keeping and retention requirements for both VCSB 

alternative and non-VCSB test methods. Parties would need to maintain 

qualification records for demonstrating compliance for a period of 5 years after they

cease use of the particular test method. Parties must also maintain a complete 

description of the test method and data with statistical analysis that supports its 

qualification.

We also sought comment on whether the Agency should require 

qualification of all analytical test method for the fuel parameters of 40 CFR 80. 

This would include each designated test method, all alternative test method 

currently allowed by our regulations, as well as any other analytical test method 

regardless of whether the test method was developed by a voluntary consensus 

standards based organization, like ASTM, or if it is a proprietary analytical test 

method, that is, non-VCSB test method.

We recognized that imposing the qualification requirement on existing and 

operational installations of all methods without adequate lead time may be 

problematic. We thus proposed to give laboratories (i.e., those in operation when 

the proposal was published (May 21, 2013)) a grace period of one year from the 

effective date of the final rule prior to complying with the requirements being 

 

527 ASTM D6708-08, entitled, Standard Practice for Statistical Assessment and Improvement of 

Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a 

Material.

528 ASTM D6708-08, entitled, Standard Practice for Statistical Assessment and Improvement of 

Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a 

Material.
Page 434 of 529

finalized in today’s rule. We explained that we believed that a year should be 

enough time to determine whether an existing test method is likely to qualify or to 

adopt and qualify a replacement test method if it should fall short. New 

installations of previously accepted methods, including alternatives, would be 

required to qualify their laboratory before being put into service just like all other 

installations of new test methods in a laboratory (78 FR 29964-29965).

All comments received were in support of our proposal to require 

qualification of only non-VCSB test methods for fuel parameters. We also received 

several comments requesting a compliance period of 18 months from the effective 

date of this rule rather than one year. According to commenters, this period of time 

was needed by the regulated community to help ensure adequate lead time to 

implement this new performance based measurement system program especially 

because there of expected modifications based on comments that were received on 

the proposed PBMS requirements. Thus, there will be a need for further 

clarification and implementation guidance beyond what was proposed and finalized 

today. Some commenters noted the discrepancy between the preamble and 

regulatory text as it related to the proposed exemption for installations of designated 

test methods of method-defined parameters that were in use six months prior to 

publication of the proposed rule. Consistent with our proposal, the Agency today is 

finalizing requirements for qualification of only non-VCB test methods for fuel 

parameters, as proposed. We are also finalizing as proposed the exemption of 

existing (i.e., in use for six months prior to May 21, 2013) installations of 

designated test methods from today’s qualification requirements. Further, in 

response to comments and in a change from our proposal, we are now providing a 

compliance period of 18 months from the effective date of this final rule for when 

these performance based analytical test methods measurement system requirements 

at 40 CFR 80.47 will be effective.

3. Downstream Pentane Blending

Today’s action finalizes provisions to allow blender grade pentane to be 

blended into previously certified gasoline (PCG) downstream of a crude oil 

refinery.

529

 These provisions will become effective [INSERT DATE 60 DAYS 

AFTER PUBLICATION IN THE FEDERAL REGISTER]. These provisions that 

are being finalized today are similar to the long standing provisions for blending 

butane into gasoline at 40 CFR 80.82, with additional provisions to provide 

adequate compliance assurance. 

Refiners are not able to produce gasoline or BOBs that are as close to the 

applicable maximum volatility (RVP) standard in a given area as what can be 

 

529 Blender grade pentane refers to pentane that meets the specifications for either commercial grade

or non-commercial grade pentane discussed below and as such may be added to previously certified 

gasoline by pentane blenders meeting the requirements finalized today. .
Page 435 of 529

achieved at a terminal through RVP trimming due to spatial and temporal 

considerations regarding the shipment of gasoline to terminals. Butane is currently 

blended into PCG downstream of the refinery in order to trim RVP levels closer to 

the applicable maximum RVP specifications. Butane blenders are required to test 

the finished gasoline they produce to demonstrate compliance with the maximum 

RVP requirements. Testing for RVP is quick, and requires relatively inexpensive 

and easy to operate equipment. Hence, RVP testing can be accommodated at a 

terminal where small (tank truck sized) batches are continually produced by

blending for delivery to retail stations. Testing for other fuel parameters such as 

sulfur and benzene content requires more costly and technically demanding 

equipment that cannot readily be accommodated at a terminal. Such testing can 

also not be completed in a time frame that is compatible with the need for terminals 

to quickly move product to retailers in order to maintain adequate supply for 

consumers. These considerations informed the Agency’s prior decision to allow 

butane blenders to primarily rely on testing conducted by the butane supplier (and 

the producer of the PCG) to demonstrate compliance with gasoline fuel quality

requirements other than maximum RVP.530 The same considerations exist today

regarding blending pentane into PCG. Therefore, we are finalizing provisions to 

allow pentane blenders to also primarily rely on testing conducted by the pentane 

producer or importer and the producer of the PCG to demonstrate compliance with 

gasoline fuel quality requirements other than maximum RVP. We are requiring that 

the test results on the pentane be generated by the producer or importer of the 

pentane because we believe that it is necessary to identify a specific party that must 

register with EPA and be responsible for the pentane quality requirements. 

The fuels regulations place primary responsibility for sampling, testing, 

reporting and assuring that gasoline meets applicable fuel standards on refiners. 

The flexibility that this rule provides to butane blenders and pentane blenders does 

not shift this primary compliance obligation. The rule does, however, provide a 

limited flexibility for refiners who add these blendstocks to previously certified 

gasoline. The agency has provided this limited flexibility because of the unique 

nature of these blendstocks, and because of additional compliance requirements that 

are imposed on the manufacturers of these blendstocks and the refiners who use 

these blendstocks. Refiners who use the special allowance for butane and pentane 

blending will remain liable for any fuel quality violations, but will be able to rely on 

sampling and testing from the butane and pentane manufacturer, if all of the 

requirements of the regulations are met. All other refiners, including blenderrefiners, must comply with all of the applicable sampling, testing, reporting 

recordkeeping and fuel quality standards, and may not rely on test results from 

blendstock suppliers. 

 

530 Regulation of Fuels and Fuel Additives: Modifications to Standards and Requirements for 

Reformulated and Conventional Gasoline Including Butane Blenders and Attest Engagements; Final 

Rule, December 15, 2005, 70 FR 74552. 
Page 436 of 529

As discussed in Section V.C. of today’s preamble, the current butane sulfur 

cap will also apply to blender grade pentane blended into gasoline by until the 

implementation of today’s Tier 3 sulfur requirements, when a 10 ppm sulfur cap 

will apply to both butane and pentane blended into gasoline. The benzene, olefins, 

and aromatics specifications for “commercial grade” and “non commercial grade” 

blender grade pentane discussed below are similar to the requirements for butane. 

We received comments in favor of our proposal to allow pentane blending 

into PCG. During our discussions with stakeholders following the proposal and 

from the review of public comments, we became aware of additional potential 

issues associated with assuring the quality of pentane for gasoline blending beyond 

those that exist for butane.531 In response to comments and to further limit 

variability in pentane quality, C6 and higher hydrocarbons in pentane blended into 

gasoline must be limited to 5 volume percent or less. We were also made aware of 

the possibility that parties that handle natural gasoline liquids (NGL) might 

misinterpret the pentane blending provisions finalized today to apply to natural gas 

liquids. A pentane stream for gasoline blending does not currently exist, and there 

are currently varying definitions of NGL, which is sometimes referred to pentanesplus. There is also concern about potential contamination if the same equipment is 

used to transport blender grade and NGL. Today’s rule finalizes the following 

additional requirements, that will preclude potential confusion of NGL with blender 

grade pentane, help ensure that the quality of blender grade pentane is maintained 

throughout the distribution system, and facilitate EPA enforcement and compliance 

assurance of the quality requirements for blender grade pentane.

First, producers and importers of pentane for gasoline blending must register 

with EPA. Such registrations must include sufficient information to demonstrate 

that the producer or importer will be capable of producing or importing blender 

grade pentane meeting today’s quality specifications and that contamination during 

distribution to the pentane blender can be adequately limited. Second, producers 

and importers of pentane for gasoline blending must test each batch of blender 

grade pentane to demonstrate that the quality requirements are met. Third, 

producers and importers of pentane for gasoline blending must submit an annual 

report to EPA that includes batch test data and information on the volume produced 

or imported. These requirements will enable EPA to perform effective oversight of 

entities that produce pentane for use by pentane blenders. 

Fourth, pentane blenders must use only blender grade pentane from 

registered producers or importers. We believe that this requirement will provide 

additional assurance that pentane blenders are obtaining product only from 

legitimate producers. Fifth, pentane blenders must conduct periodic quality

assurance testing on both the commercial grade pentane and the non-commercial 

 

531 See the Summary and Analysis of Comments for this rule for a detailed response to comments on 

the pentane blending provisions finalized today.
Page 437 of 529

grade pentane that they receive. Sixth, we are requiring a more frequent sampling 

frequency than is required for butane. For commercial-grade pentane, pentane 

blenders must sample and test once for every 350,000 gallons of pentane received, 

or once every three months, whichever is more frequent. For non-commercialgrade pentane, pentane blenders must sample and test once for every 250,000 

gallons of pentane received, or once every three months, whichever is more 

frequent. We believe that the heightened level of concern regarding assuring the 

quality of pentane used by downstream blenders warrants these additional 

requirements. 

Finally, we are finalizing specific product transfer document and 

recordkeeping requirements for parties that produce and take custody of pentane for 

gasoline blending. Entities in the distribution chain for blender grade pentane must 

maintain records of their quality assurance activities to manage contamination while 

blender grade pentane is in their custody. We proposed amendments to 40 CFR

80.79 to address the liability and prohibited activities for entities in the blendergrade pentane distribution system. During our review of the regulations finalized 

today, we noted that such provisions are already covered under existing regulations 

that pertain to entities in the distribution system for butane used by downstream 

butane blenders as well as other parties. Therefore, we are not finalizing the 

proposed amendments to 40 CFR 80.79. 

A parties that blends pentane into gasoline is a refiner, similar to butane 

blenders. Similar to the butane blending provisions, pentane blending will not be 

allowed into RFG or RBOB from April 1 through September 30, or into any RFG 

or RBOB that is designated as VOC-controlled. Like butane blenders, pentane 

blenders must test the finished gasoline to ensure that the applicable volatility

requirements are met. Consistent with the requirements for butane blenders, 

pentane blenders will not be subject to other sampling and testing requirements that 

would otherwise apply to a refiner, provided that they use blender grade pentane 

that meets today’s specifications and conduct today’s specified quality assurance 

practices.

Testing to demonstrate compliance with gasoline compositional 

requirements other than maximum RVP will not be required for pentane blender 

provided that the blender has product transfer documents from the supplier that 

demonstrate the pentane is “commercial grade”. Until December 31, 2016, 

commercial grade pentane is defined as pentane that test results demonstrate is 95 

percent pure and has the following properties: sulfur ≤ 30 ppm, benzene ≤ 0.03 

volume percent, olefins ≤ 1.0 volume percent, aromatics ≤ 2.0 volume percent, and 

C6 and higher hydrocarbon content ≤ 5.0 volume percent. Beginning January 1, 

2017, a sulfur standard of ≤ 10ppm will apply while the other specifications for 

commercial grade pentane will remain unchanged. Product transfer documents 

from the supplier demonstrating the pentane is “non-commercial grade” may also 

be used to demonstrate compliance with gasoline quality requirements other than 

volatility. Until December 31, 2016, non-commercial grade pentane is pentane that 

test results demonstrate as having the following properties: sulfur ≤ 30 ppm, 
Page 438 of 529

benzene ≤ 0.03 volume percent, olefins ≤ 10.0 volume percent, aromatics ≤ 2.0 

volume percent, and C6 and higher hydrocarbon content ≤ 5.0 volume percent. 

Beginning January 1, 2017, a sulfur standard of ≤ 10ppm will apply while the other 

specifications for non-commercial grade pentane will remain unchanged. As 

discussed above, producers and importers of pentane for gasoline blending must test 

each batch of finished gasoline to demonstrate compliance with these quality

requirements.

The pentane parameter testing that is required of pentane producer/importers 

and pentane blenders must be conducted using test procedures that have been 

approved by the Administrator. No such test procedures are currently approved. 

As part of their registration requirements, pentane producers and importers must 

specify the test procedures that they will use to demonstrate compliance with the 

pentane quality requirements finalized today. EPA will continue to work with 

industry in establishing test procedures for use in meeting pentane testing 

requirements. 

We believe that the butane blending provisions have reduced the burden of 

compliance with EPA gasoline quality requirements. We anticipate that expanding 

these provisions to allow pentane to be blended into gasoline will further reduce the 

burden of compliance. The requirement that final blends must comply with 

maximum gasoline volatility requirements will ensure that the flexibility to conduct 

downstream RVP trimming will not reduce the environmental benefits of EPA’s 

gasoline quality requirements. Due to its lower volatility compared to butane, 

larger volumes of pentane than butane can be blended into gasoline while still 

meeting the gasoline RVP standards. Thus, allowing pentane to be blended into 

gasoline downstream of the refinery may displace butane blending. Since pentanes 

have a lower boiling point than butane, this could result in some environmental 

benefit from reduced vehicle evaporative emissions. A prominent butane blender 

stated that allowing pentane blending would provide an opportunity to increase 

domestic gasoline supply which in turn could help reduce gasoline prices. 

One commenter requested that the blending flexibility for pentane be 

extended to other gasoline range hydrocarbons such as heavy naptha. We disagree. 

We are not expanding today’s provisions beyond pentane. Pentane is a clean 

burning alkane like butane. The only concern with respect to the effect of 

downstream pentane and butane blending on vehicle emissions can be addressed 

through compliance with gasoline maximum volatility requirements. Less is known 

about the potential impacts on vehicle emissions of the downstream blending of 

blendstocks other than butane and pentane. We note that such blendstocks can still 

be utilized by refiners. 

Allowing blending of heavier boiling range hydrocarbons, such as heavy 

naptha, would also likely raise additional compliance assurance issues. Similar to 
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butane, blender grade pentane requires special pressure vessels for transport, 

storage, and blending into gasoline due to its relatively high vapor pressure / boiling 

point.532 These special equipment and handling needs present a significant barriers 

to entry into the pentane blending market, thereby limiting the potential number of 

parties engaged in the market. The substantial investments needed for such special 

equipment also provides assurance that parties engaged in the pentane blending 

market will be motivated to comply with EPA requirements. These factors make us 

confident that the compliance assurance requirements finalized today are sufficient 

to support provisions for pentane blending. On the other hand, in the case of 

heavier hydrocarbons that are liquid under ambient conditions, gasoline handling 

equipment could be used. This would greatly multiply the number of potential 

parties that could supply product to downstream blenders, thereby substantially

increasing compliance assurance concerns. Therefore, we are not finalizing 

provisions for downstream blending other than those for pentane at this time.

4. Acceptance of Top Tier Deposit Control Test Data

Today’s action finalizes the proposed amendments to EPA’s gasoline 

deposit control regulations to accept test data collected for the industry-based “TopTier” deposit control program as demonstration of compliance with EPA’s intake 

valve deposit (IVD) and fuel injector deposit (FID) control requirements. The “Top 

Tier” deposit control gasoline standards developed by four major automakers are 

based on the premise that a more robust level of the control of vehicle engine and 

fuel systems beyond that provided by the EPA deposit control requirements is 

desirable and necessary for current vehicle technology.

533

 Several major gasoline 

marketers have adopted Top Tier for their gasoline. It is widely accepted that 

conformance with the Top Tier IVD and FID control testing requirements is more 

challenging than complying with the standard EPA IVD and FID testing 

requirements. Accepting IVD/FID test data that complies with the Top Tier 

requirements in place of the standard EPA IVD/FID testing requirements will

provide significant savings to industry from reduced deposit control testing while 

maintaining the emissions benefits of EPA’s gasoline deposit control program. 

These changes are being codified in the regulations at §§80.161(b), 

80.163(a)(1)(iii), 80.164(a), 80.165, 80.167(a), 80.176, and 80.177.

The comments we received were in favor of the proposal to accept test data 

that demonstrates compliance with the Top Tier program as alternative compliance 

data under EPA’s deposit control program. Chevron stated that their extensive 

experience with deposit control and related vehicle/engine performance testing, 

combined with the vast body of technical literature on the subject, shows that 

compliance with Top Tier IVD/FID requirements provides improvements in 

emissions and performance compared to fuels with deposit control additive levels 

 

532 The boiling point of pentane is ~ 97° F and butane is ~30° F.

533 The industry-based Top Tier deposit control program is discussed at http://www.toptiergas.com/
Page 440 of 529

that merely meet EPA’s deposit control requirements. Chevron identified a 

typographical error in the proposed regulations to codify the Top Tier testing 

requirements at §80.177(b)(1)(iv). The proposed regulations stated that test fuel 

used in IVD testing must contain no less than 240 ppm sulfur. This error is 

corrected in the regulations finalized today to state that test fuel used in IVD testing 

must contain no less than 24 ppm sulfur, consistent with the Top Tier deposit 

control standard.

5. Potential Broader Regulatory Streamlining Through Program 

Restructuring

The current set of fuel regulations is the result of programs that have been 

established over the years to reduce emissions from mobile sources. These 

programs include gasoline volatility (RVP), reformulated gasoline and antidumping, sulfur control (which today’s Tier 3 program will revise), mobile source 

air toxics (MSAT1), benzene control (MSAT2), and the renewable fuel standards 

(RFS). Most of these regulations have been amended numerous times.

The RFG and anti-dumping regulations in particular contain some of the 

more extensive requirements on sampling, testing, and reporting. They also have 

some of the more stringent restrictions on gasoline use (e.g., restricting where fuel 

produced can be sold, what it may be commingled with, etc.). EPA used the RFG 

and anti-dumping rules as the foundation for many aspects of subsequently 

developed fuel regulatory programs. However, the subsequent rules, considered as 

a whole, have supplanted most of the RFG and anti-dumping standards. For this 

reason, we proposed to streamline the regulations in several places as described 

above. Initial discussions with fuel industry representatives have indicated that a 

comprehensive review of the complete set of fuel regulations contained in 40 CFR 

parts 79 and 80 (“Registration of Fuels and Fuel Additives” and “Regulation of 

Fuels and Fuel Additives,” respectively) of the Code of Federal Regulations could 

lead to further streamlining of the regulations beyond the streamlining provisions

being finalized today. EPA expects that further streamlining would result in more 

efficient and less costly compliance determinations for affected parties while 

maintaining the environmental benefits of the programs. However, in many cases

such changes could require not just the removal or streamlining of existing 

provisions but also the replacement of several provisions with new, less onerous 

ones that require further development, notice and comment. We intend to continue 

to seek comment in future actions on potential areas in the fuel regulations that may

benefit from such a more comprehensive streamlining effort. For example, it may

be possible for the RFG VOC standard to be met if a sufficiently stringent RVP 

level is attained. Under this scenario, sampling and testing requirements at the 

refinery would be reduced. Another potential scenario could involve consolidation 

of some RFG and anti-dumping rules; for example, a single set of rules governing 

the treatment of downstream ethanol blending and in-use surveys could provide 

greater efficiency and flexibility regarding fuel distribution.
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We received a number of comments supporting the concept of further 

streamlining in 40 CFR parts 79 and 80, including suggestions for additional areas 

of the regulations to consider in the future.

B. Engine, Vehicle and Equipment Programs Amendments

We are amending several regulatory requirements for motor vehicles and 

other types of vehicles and engines. These changes are intended to align with the 

Tier 3 standards and to make various adjustments and corrections to the regulations. 

We are also removing large portions of obsolete regulatory text and updating cross 

references accordingly. 

1. Fuel Economy Labeling

EPA adopted updated fuel economy labeling requirements in 40 CFR part 

600 on July 6, 2011.534 The label displays a smog rating based on relative emission 

rates for certified vehicles. With new Tier 3 standards, this rating scale becomes 

less useful, since the Tier 3 standards disallow certification to half of the existing 

smog ratings. We are therefore adopting a new transitional smog rating scale 

starting in model year 2018. Manufacturers choosing to transition to the Tier 3 

NMOG+NOX standards based on a percentage phase-in may continue to meet Tier 

2 standards for the “phase-out” fraction of the fleet through model year 2020, but 

must use a new smog rating scale that lines up, to the extent possible, the Tier 2 

standards with the new Tier 3 scale. We believe it is appropriate to shift to the new 

transitional smog rating scale in model year 2018 to reflect the start of Tier 3 

program for the majority of vehicles. 

The smog rating scale ranges from 1 to 10. The federal Tier 3 program 

comprises seven different NMOG+NOX emission certification levels. In addition, 

the California ZEV program for 2018 and later model years includes a unique 

TZEV category, which falls between a ZEV (Bin 0) and a SULEV20 (Bin 20), 

resulting in a total of eight emission standards.535 EPA received comment asking 

that we develop appropriate ratings that account for both the exhaust certification 

and all-electric range of TZEV vehicles. EPA plans to develop guidance for smog 

ratings for TZEV vehicles in its annual fuel economy guidance letter. Therefore we 

are not finalizing a smog rating for California TZEV vehicles at this time. As 

proposed, we are omitting rankings 2 and 4 to help convey the larger absolute 

differences in the g/mile standards between Bins 70 and 125 and Bins 125 and 160. 

We are also adjusting the scale again in model year 2025, once the Tier 3 

standards are fully implemented, so that, the middle of the scale (a smog rating of 5 

or 6) is equivalent to the fleet average standard of 0.030 g/mile for NMOG + NOx, 

consistent with the fuel economy and greenhouse gas rating.

 

534 76 FR 39478 (July 6, 2011). 

535 http://www.arb.ca.gov/regact/2012/zev2012/fro2rev.pdf
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We revised the regulations slightly after the proposal to accommodate the 

presence of LEV III vehicles in 2017 and earlier model years.

2. Removing Obsolete Regulatory Text

EPA regulations for highway and nonroad engines, vehicles, and equipment 

in many cases apply for a range of model years before being replaced by a new set 

of standards, requirements, and other provisions for implementing a program that 

changes to reflect technological innovation, changing environmental needs, new 

business dynamics, and other factors. 

We are taking steps in this rulemaking to remove substantial portions of 

regulatory text that no longer have any regulatory significance, generally because 

they have been superseded by newer provisions. In many cases, this simply

involves removing paragraphs or sections related to certifying products that no 

longer apply to 2004 or newer model years. In other cases, we can remove whole 

subparts that apply only to engines and vehicles that have reached the end of their 

useful lives for the purpose of regulation. For example, the in-use regulations from 

40 CFR part 86, subpart H, applied only for 1993 through 2003 model year lightduty vehicles, light-duty trucks, and medium-duty passenger vehicles. Also, the 

National LEV standards in 40 CFR part 86, subpart R (and in Appendix XIII 

through XVIII of part 86), applied only for 1999 through 2003 model years. These 

subparts, and references to that content, can be removed from the CFR.

Similarly, the provisions of 40 CFR part 86, subpart A, applied to light-duty

vehicles only through model year 2000 for light-duty vehicles and model year 2004 

for light-duty trucks and chassis-certified heavy-duty vehicles. Much of that 

subpart continues to apply for heavy-duty engines, so the obsolete portions must be 

removed more selectively. We are removing substantial portions of 40 CFR part 

86, subpart A, to omit text that applies only for light-duty vehicles or light-duty

trucks, and additional portions that do not apply for any 2004 or newer model years. 

There are also instances where we are streamlining the organization of 

regulatory sections in 40 CFR part 86. For those places where there is a new 

section for a given model year where all the old provisions continue to apply, and 

the new section introduces a narrow additional provision, we are copying the new 

paragraph into the section for the older model-year provisions, with descriptive 

language in place to say when the new provision applies as appropriate. This 

consolidation allows us to take out numerous sections that can lead to confusion for 

the reader. 

The following sections describe additional changes to remove material.

a. Certification Short Test and I/M Provisions

Inspection and maintenance (I/M) programs have been implemented by state 

and local governments for many years. These programs have been effective at 
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identifying vehicles that need some kind of repair to restore the performance of a 

vehicle’s emission control system. In that context, they have also provided useful 

information to facilitate warranty coverage where defective components or systems 

were still covered by the manufacturer’s warranty, as required by section 207 of the 

Clean Air Act. In 1993, EPA adopted a requirement for the certification short test 

(“CST” or “cert short test”).536 The purpose of the cert short test was to correlate 

the vehicle manufacturer’s certification and I/M testing. Under this approach, the 

vehicle manufacturer certifies that a properly maintained and operated vehicle will 

pass I/M testing. When such a vehicle fails I/M during the warranty period, the 

manufacturer is responsible for the cost of repairs necessary to correct the problem 

so the vehicle can pass the I/M test. 

EPA adopted requirements in 1993 for manufacturers to design and build 

their vehicles with OBD, which provides performance feedback for evaluating 

whether emission control systems are functioning properly. This rule, combined 

with fleet turnover, has resulted in vehicles subject to I/M being equipped with 

OBD. The standard protocol for I/M programs now depends on the OBD system 

instead of tailpipe tests to determine which vehicles need maintenance. Since 

vehicle manufacturers have to certify the performance of OBD systems as part of 

the certification process, the use of OBD for I/M testing also provides a basis for 

determining that emission repairs are covered by the manufacturer’s warranty, when 

necessary. For many years, manufacturers have submitted a compliance statement 

for certification instead of submitting data to demonstrate that they meet the 

standards associated with the cert short test. Since emission measurements are no 

longer part of any standardized I/M testing, it has become clear that OBD systems 

have completely replaced the cert short test as the means of making warranty 

determinations for I/M testing. We are therefore entirely removing the cert short 

test standards and test procedures from 40 CFR part 86, subparts O and S, and

similarly removing the emission measurement procedures from 40 CFR part 85, 

subpart W.

The remaining regulatory text in 40 CFR part 85, subpart W, relates only to 

the role of OBD testing in the determination of manufacturers’ warranty obligations 

resulting from I/M testing. In addition to removing material that no longer applies 

based on model years, we are updating this remaining text in two ways. First, we 

are expanding the scope to include medium-duty passenger vehicles since these 

vehicles are now subject to both OBD certification requirements and I/M testing. 

Second, we are replacing all citations to SAE reference procedures with a crossreference to 40 CFR 86.1806, which accounts for the relevant OBD reference 

procedures. This avoids the possibility of changing the certification procedures in a 

way that departs from the I/M and warranty provisions. Since these programs are 

paired, there will never be a need to specify different reference procedures for the 

two programs.

 

536 58 FR 58382 (November 1, 1993).
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b. Testing for Heavy-Duty Highway Engines

We recently completed the migration of test procedures for heavy-duty 

highway engines from 40 CFR part 86, subpart N, to 40 CFR part 1065. Now that 

these manufacturers are all relying on the new test procedures, we are eliminating 

the regulatory provisions that no longer apply. This involves large portions of text 

in 40 CFR part 86, subpart N, that have been superseded by analogous material in 

40 CFR part 1065, such as analyzer specifications, calibration procedures, 

calculation methods, and fuel specifications. The obsolete text also included 

several references to 40 CFR part 86, subpart D, which we will also no longer print 

in the CFR. 

We are keeping regulatory provisions in 40 CFR part 86, subpart N, that 

serve as the “standard-setting part” for matters related to testing, such as the duty

cycles and not-to-exceed test procedures. These provisions are unique to heavyduty highway engines and are therefore not suitable for the general test 

specifications in 40 CFR part 1065. We will eventually migrate these remaining 

provisions to 40 CFR part 1036, where we already describe the greenhouse gas 

emission standards and certification requirements for heavy-duty highway engines.

In the case of testing in-use engines that were originally certified using the 

procedures in 40 CFR part 86, subpart N, we are including a regulatory provision to 

allow EPA and manufacturers to continue to use the original certification 

procedures as a pre-approved alternate procedure.

c. Testing for Heavy-Duty Highway Vehicles

The regulations at 40 CFR part 86, subpart M, describe how to test heavyduty vehicles above 14,000 lbs GVWR to demonstrate compliance with evaporative 

emission standards. Most of these provisions are identical to those that apply under 

40 CFR part 86, subpart B. As described in Section IV.C, we are eliminating 

subpart M and replacing it with a simple instruction to test these heavy-duty 

vehicles using the procedures of subpart B, with a small number of appropriate 

modifications noted as exceptions to the light-duty test procedures. 

d. Service Information Requirements for Light-Duty Vehicles

The service information regulations were originally adopted for light-duty 

motor vehicles 40 CFR 86.038-96. These requirements applied for 1996 and later 

model year vehicles. Starting with the 2001 model year, these same requirements 

were copied into §86.1808-01. These two sets of requirements are identical except 

for the model year applicability and a variety of very minor stylistic differences. 

We are revising the service information regulations in §86.1808-01 to apply also to 

1996 through 2000 model year vehicles, and to correct several typographical and 

formatting errors. These changes should have no practical significance, since the 

requirements are the same in both regulatory sections.
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3. Motorcycle Driving Schedules

The CFR includes two separate driving schedules for motorcycles. The 

first, for motorcycles at or above 170 cubic centimeters (cc), is identical to that used 

for light-duty vehicles except that the speeds are converted to kilometers per hour. 

The second driving schedule, for smaller motorcycles, is also identical except for a 

period of about three minutes of reduced-speed operation. To simplify this 

arrangement, and to better incorporate the new LA-92 driving schedule described in 

Section IV.B for heavy-duty vehicles, we are eliminating the identical portions of 

these drive schedules. This revised approach involves referencing the driving 

schedule for light-duty vehicles with instructions to convert to kilometers per hour 

and round the resulting speeds to the nearest 0.1 kilometers per hour, instead of 

repeating the driving schedule just to publish the same speed trace in different units. 

The unique portion of the driving schedule is laid out, with reference to the lightduty driving schedule for the portions that are unchanged. This is not intended to 

cause any change in the current requirements or practices for certifying 

motorcycles.

4. Updating Reference Procedures

The regulations in 40 CFR part 1065 depend on a large number of reference 

procedures and technical standards from ASTM, SAE International, and ISO, 

among others. These reference procedures and technical standards are updated 

periodically to keep them current with ongoing developments in the field. Many

times these changes include only minor corrections or clarifications. In other cases 

the updates incorporate new test methods, accommodate changing engine 

technologies, or other more substantive changes. Whether the updated reference 

documents involve major changes or not, it is important for the regulations to rely

on documents that are readily available. Toward that end, we are updating 

§1065.1010 with the latest versions of all the reference procedures and technical 

standards that we were able to identify. 

In areas of the regulations other than part 1065, we are generally updating 

the regulation to rely on the latest reference documents where we are changing or 

adding a provision that depends on one of these reference documents, but we are 

not making broad or universal changes to these references in other parts of the 

regulation.

One particular area of interest relates to rounding. As described in Section 

IV.H.3, we are defining “round” for 40 CFR part 86 to have the meaning we give in 

40 CFR 1065.20, which spells out a detailed rounding protocol that is consistent 

with ASTM E29 and NIST SP811. This definition of “round” will defer to existing 

references in part 86 so that the part 1065 protocol will apply only where we do not 

specifically refer to ASTM E29. This is not intended to change the policy for 

calculating or reporting numerical quantities, but rather to clarify the protocol and 

avoid the administrative complication of referencing multiple versions of the 

ASTM document. We expect to eventually remove all mandatory references to 
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ASTM E29 and NIST SP811 and rely exclusively on §1065.20 as the method for 

rounding numerical quantities.

VII. What are the Cost Impacts of the Rule?

We have estimated the costs for both the vehicle standards described in 

Section IV and the fuel standards described in Section V. This section summarizes 

these costs, while further information on the methodology we used to develop these 

costs can be found in Chapters 2 and 5 of the RIA.

Section VII.C provides a summary of total costs for the final vehicle and 

fuel programs together. For a comparison of the program costs to the monetized 

health and welfare benefits, see Section VIII.

A. Estimated Costs of the Vehicle Standards

To determine the cost for vehicles, we first determined which technologies 

were most likely to be applied by vehicle manufacturers to meet the standards. 

These technologies were then combined into technology packages which reflected 

vehicle design attributes that directly contribute to a vehicle’s emissions 

performance. The attributes considered included vehicle type (car or truck), 

number of cylinders, engine displacement, and the type of fuel used (gasoline or 

diesel). We also created separate packages for light-duty and heavy-duty trucks and 

vans. In estimating both cost and technology application, we have relied on 

publicly available information (such as that developed by California or submitted as 

comments on the proposal), confidential information supplied by individual 

manufacturers and suppliers, and the results of our own in-house testing. The 

technology packages that we developed represent what we consider to be the most 

likely average emissions control solution for each vehicle type.

In general, we expect that the majority of vehicles will be able to comply

with the Tier 3 standards which we are adopting through refinements of current 

emissions control components and systems. Some vehicles may require additional 

emission controls, such as large trucks with large displacement engines (in 

particular, LDT3s and LDT4s). Overall, smaller, lighter-weight vehicles will 

require less extensive improvements than larger vehicles and trucks. Specifically, 

we anticipate a combination of technology upgrades including:

 Catalyst Platinum Group Metal (PGM) Loading. Increased catalyst 

application of precious metals.

 Optimized Close-coupled Catalyst: Improvements to the catalyst system 

design, structure, and packaging to reduce light-off time.

 Optimized Thermal Management: Overall thermal management of the 

emissions control system to shorten the time it takes for the catalyst to 

light-off.
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 Secondary Air Injection: Increased application of secondary air 

injection for some 6-cylinder and larger engines.

 Engine Calibration: Engine control and calibration modifications to 

improve air and fuel mixtures, particularly at cold start and/or to control 

secondary air and hydrocarbon adsorbers.

 Hydrocarbon Adsorber: Limited application of hydrocarbon adsorbers 

to trap hydrocarbons during cold start and release the hydrocarbons after 

the catalyst lights off.

 Evaporative Emissions Controls: Improved evaporative emissions 

systems, including canister scrubbers, more permeation-resistant 

materials, and improved system integration.

1. What Changes Have Been Made to Vehicle Program Costs Since 

Proposal?

Chapter 2 of the final RIA contains details about what changes have been 

made since the proposal and why we have made those changes. We have made 

several changes since the proposal, but two changes have significant impacts on the 

final rule vehicle costs and help to explain the large reduction in cost estimates 

between proposal and final rule. The first of these significant changes involves the 

catalyst platinum group metal (PGM) loading costs. As commenters pointed out, 

the cost estimates in the proposal have become dated, as they were based largely on 

four-year-old estimates of the CARB LEVIII program. For this final rule, we have 

developed a more robust catalyst loading cost estimate using a methodology 

suggested by one commenter.537 This more robust estimate results in lower costs 

than estimated in the proposal.

The second significant contributer to reduced final rule cost estimates is the 

use of the MY 2017-2025 fleet mix projected to result from the most recent GHG 

and fuel economy rules. That projected fleet mix shows a large percentage of fourcylinder engines (generally these are inline engines, or I4), which are less costly to 

modify to achieve Tier 3 compliance than the proposal’s projected MY 2012-2016 

fleet mix, which included many more V-configuration six-cylinder (V6) and eightcylinder (V8) engines. We mentioned in the preamble to the proposal our intention 

to use the projected MY 2017-2025 fleet for our final rule cost analysis (see 78 FR 

29970).

We have made many other updates to the analysis for this final rule. For 

example, we reviewed the MY2013 certification database to evaluate the certified 

 

537 ICCT Comments in Response to the Tier 3 Proposed Rulemaking, Docket ID No. EPA-HQOAR-2011-0135-4304; Posada, Francisco, et. al., “Estimated Cost of Emission Control 

Technologies for Light-Duty Vehicles Part 1 – Gasoline,” SAE 2013-01-0534, 4/8/2013.
Page 448 of 529

emission levels of the fleet. We found that many vehicles are already being 

certified with emission levels that would meet final Tier 3 standards. Further, many 

vehicles have certified emission levels that are 70% of the 0.30 g/mi NOx+NMOG 

standard, meaning that sufficient compliance margin exists for those vehicles to 

comply with Tier 3 without any additional costs.538 Our final rule estimates no 

exhaust emission-related Tier 3 costs for these vehicles (evaporative emissionrelated costs are discussed below).

We have also concluded that active HC adsorbers are not expected on any

vehicles and, instead, a passive HC adsorber will be used. The passive HC adsorber 

is considerably less costly. We base this on comments from MECA and ICCT and 

on confidential business information (CBI) provided by Tier 1 suppliers after the 

proposal.539 We have also decreased our evaporative emission control costs, in part 

because of the high penetration of gasoline engines with direct injection as 

projected by the MY 2017-2025 GHG and fuel economy rules. Direct injection 

removes a large source of evaporative emissions and, thus, means fewer vehicles 

need to add certain evaporative control technologies. We have also decreased the 

penetration rates of secondary air injection in the later years of the program, for 

reasons described below. Lastly, we have modified very slightly our indirect cost 

markups to account for the fact that most of the research and development efforts 

required of auto makers are in response to CARB’s LEVIII rule and need not be 

conducted again for Tier 3 compliance.

We have made some changes that have increased costs, although the cost 

increases are smaller in magnitude than the cost decreases from other changes so, 

on net, estimated vehicle-level costs are lower than in the proposal. One such 

change was to increase the engine calibration costs (from roughly $2/vehicle to 

$5/vehicle), to cover expected calibration efforts associated with PM control on 

direct injected gasoline engines. We have also increased the penetration rates of the 

technology we term “optimized thermal management” for some vehicle classes. 

This was done to ensure that all vehicles adding technology include costs for either 

optimized close-coupled catalysts or optimized thermal management by setting the 

combined phase-in rate in each vehicle category to 100%. Another change was to 

update all costs from 2010 dollars to 2011 dollars.540 

 

538 As discussed in Section IV, we expect manufacturers to target 60-80% of the standard, or 20-40% 

compliance margins under Tier 3.

539 See ICCT, Docket ID No. EPA-HQ-OAR-2011-0135-4304, at page 11 of 21; see MECA, Docket 

ID No. EPA-HQ-OAR-2011-0135-4675, at page 3 of 7.

540 We have updated 2010 dollars to 2011 dollars using the Gross Domestic Product (GDP) price 

deflator as reported by the Bureau of Economic Analysis on May 30, 2013. The factor used, taken 

from Line 1 of Table 1.1.4 Price Indexes for Gross Domestic Product, was 1.035 to convert from 

2009$ and 1.021 to convert from 2010$. For example, to convert from 2010$ to 2011$, we 

calculated the (value in 2010$)x1.021=(value in 2011$).
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With respect to total program costs, the significant change since proposal 

was to exclude costs incurred on vehicles sold in all states (California and 

elsewhere) that have adopted the California LEVIII program. As a result, our 

estimated costs per vehicle are applied to millions fewer vehicles in the final rule, 

thus making the total program costs considerably lower. And finally, we have 

included operating savings (fuel savings) associated with avoiding the loss of fuel 

that would have otherwise evaporated absent the new Tier 3 controls. The 

otherwise evaporated fuel is ultimately used to propel the vehicle, thus providing a 

savings to the consumer.

2. Summary of Vehicle Program Costs

As in the proposal, we have developed our costs with respect to a given 

vehicle type and the type of engine with which it is equipped. The final cost per 

vehicle is the result of not only the cost per technology, but also the application rate 

of that technology for each vehicle type. For example, while the $119 (2017 cost in 

2011$) cost of secondary air injection is the same for both a 6-cylinder (V6) and 8-

cylinder (V8) application, we anticipate that only 25 percent of the V6 and 75 

percent of the V8 passenger car applications will require it in MY2017. In the same 

way, we anticipate that light truck applications will not add that technology until 

MY2018, again at a 25%/75% penetration rate for V6/V8 applications, respectively. 

Table VII-1 below shows our estimate of the cost of each of the emission control 

technologies for the gasoline vehicles affected by this final rule. Table VII-2

provides the anticipated application rate of the technology by vehicle type. Note 

that all of the costs shown in this section are in 2011 dollars and are marked-up by

an Indirect Cost Multiplier (ICM) so they include both direct and indirect costs. 

(For details of regarding ICMs and their application refer to Chapter 2 of the RIA.)
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Table VII-1 MY2017 Technology Costs by Gasoline Engine Type (2011$)a

Technology PC 

I4

PC 

V6 PC V8 LT I4

LT 

V6

LT 

V8

HDc

Class 

2b

HD 

Class 

3

>14K 

HD d

Catalyst 

Loading 

$43 $68 $101 $50 $75 $108 $59 $59 N/R

Optimized 

Closecoupled 

Catalyst

$24 $48 $71 $24 $48 $71 N/R N/R N/R

Optimized 

Thermal 

Management

$36 $36 $36 $36 $36 $36 $36 $36 N/R

Secondary

Air Injection N/Rb

$119 $119 N/R $119 $119 N/R N/R N/R

Engine 

Calibration $5 $5 $5 $5 $5 $5 $5 $5 N/R

Hydrocarbon 

Adsorber N/R N/R $20 N/R N/R $20 N/R N/R N/R

Evaporative 

Emissions 

Controls

$15 $15 $15 $14 $14 $14 $11 $17 $17

a

PC=passenger car; LT=light truck; I4=In-line 4-cylinder; V6= 6-cylinder, V8= 8-cylinder

b N/R – Not Required

c Heavy-duty

d Gasoline only
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Table VII-2 Technology Application Rates for Gasoline Vehicles

Technology PC I4 a PC V6 a PC V8

a LT I4 b LT V6b

LT 

V8 b

Class 

2b & 3 

b

>14K 

HD c

Catalyst 

Loading 100% 100% 100% 100% 100% 100% 100% 0%

Optimized 

Closecoupled 

Catalyst

50% 60% 75% 50% 60% 75% 0% 0%

Optimized 

Thermal 

Management

50% 40% 25% 50% 40% 25% 25% 0%

Secondary

Air Injection

d

0% 25% 75% 0% 25% 75% 0% 0%

Engine 

Calibration 100% 100% 100% 100% 100% 100% 100% 0%

Hydrocarbon 

Adsorber 0% 0% 15% 0% 0% 15% 0% 0%

Evaporative 

Emissions 

Controls

100% 100% 100% 100% 100% 100% 100% 100%

a MY2017 and later

b MY2018 and later (Note that, for the vehicle cost analysis, LDT1/2/3/4 are treated 

collectively as light trucks.)

c Gasoline only

d

Secondary air injection penetration rates ramp down from values shown here as follows: 

Passenger car and light truck V6 gasoline: 25/25/25/15/15/5/5/5/5% beginning in 2017 

except for light trucks which have a 0% penetration in MY2017; Passenger car and light

truck V8: 75/75/75/65/65/55/55/45/45% beginning in 2017 except for light trucks which 

have a 0% penetration in MY2017.

Note the footnote to Table VII-2 describing the penetration rates used for 

secondary air injection systems in V6 and V8 gasoline vehicles. In the proposal, we 

did not use a ramped down penetration rate like that being used in this final rule for 

this technology. We have revised the penetration rates in this final rule because of 

the historical pattern by which secondary air injection has been implemented in the 

light-duty fleet. Generally, secondary air makes an appearance in the early 

implementation stages and then is slowly phased out as auto makers learn more 

about and become more comfortable with their ability to meet any new emission 

standards with a lower degree of reliance on secondary air. Presumably, this 

technology is added in the early stages because it provides effective and relatively

easily implemented cold temperature control for difficult applications in which auto 

makers tend to consider every technique at their disposal to ensure full useful life 

compliance. Then, as experience is gained, the secondary air injection systems 
Page 452 of 529

slowly disappear from the new light-duty fleet due to its relatively high cost. We 

expect a similar implementation pattern in response to Tier 3. This position is 

corroborated by ICCT in their comments where they say, in the context of LEV II 

vehicles meeting the LEV III standards, “In some cases it was easier and cheaper 

for manufacturers to add existing hardware (i.e., secondary air injection) than to 

invest the engineering resources to fully optimize precise air/fuel control and fast 

light-off strategies, or to develop new hardware” (emphasis added).541 

Medium Duty Passenger Vehicles (MDPVs) were included in the light-duty 

fleet as part of Tier 2. Given their current certification requirements for criteria 

pollutants, we have included the costs for MDPVs to meet the Tier 3 standards with 

the light truck cost estimates. We do not expect that the technologies required to 

meet the Tier 3 standards for MDPVs will be different from those applied to light 

trucks (with V8 engines), as in many cases there are identical powertrains and 

chassis between the large light truck and MDPV platforms.

We also expect that some manufacturers may continue to build and sell 

light-duty diesel vehicles and certify those vehicles to Tier 3. All light-duty diesel 

vehicles currently being sold in the federal fleet are equipped with some means of 

controlling NOX emissions, either a Lean NOX Trap (LNT) or selective catalytic 

reduction (SCR) system. As these systems are already very effective in controlling 

NOX emissions, we expect that they will remain the primary emissions control 

systems to meet Tier 3. Similar to gasoline engines, diesel powertrains may be 

required to improve the effectiveness of their emission control systems during cold 

start. Therefore, we have developed our costs for diesels with the expectation that 

the incremental costs will be realized to improve LNT and SCR systems during cold 

start. The improvements have been categorized as general SCR optimization, 

which include packaging changes to the SCR system to allow faster light off; 

optimized thermal management, to reduce the thermal mass of the system and allow 

more of the combustion heat to reach the SCR system sooner; and the calibration 

work associated with both of these changes. Table VII-3 below describes both the 

cost of the technologies as well as their anticipated application rates.

Table VII-3 MY2017 Technology Costs and Application Rates for Diesel 

Engines (2011$)

Technology

Diesel Engine 

Costs

(all types)

Light-duty and 

Heavy-duty 

Application 

Rate

Optimized Thermal Management $36 25%

Engine Calibration a$2 100%

SCR Optimization $59 100%

 

541 See EPA-HQ-OAR-2011-0135-4304 at page 11 of 21.
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a These engine calibration costs are the same as the proposal since the increased 

calibration costs associated with gasoline direct injection do not apply for diesels.

We also estimated costs for HDVs between 8,501 and 14,000 lbs GVWR

and for gasoline HDVs above 14,000 lbs. Vehicles in this range are often referred 

to as Class 2b (8,5001-10,000 lbs), Class 3 (10,001-14,000 lbs) and Class 4 and 

above (>14,000 lbs) vehicles and are typically full-size pickup truck and work vans. 

We applied the same process to the heavy-duty vehicles as we did to the light-duty

vehicles. Heavy-duty costs and application rates are included in Table VII-1, Table 

VII-2, and Table VII-3 above. 

We have also considered the impacts of manufacturer “learning-by-doing” 

on the technology cost estimates. We reflect the phenomenon of volume-based 

learning curve cost reductions in our modeling using two algorithms, depending on 

where in the learning cycle (i.e., on what portion of the learning curve) we consider 

a technology to be: the “steep” portion of the curve for newer technologies and 

“flat” portion of the curve for more mature technologies. We have made no 

changes to the application of learning curve cost reductions relative to the proposal. 

For details surrounding learning-by-doing, please refer to Chapter 2 of the final 

RIA. 

The evaporative emissions standards that we are adopting will impose 

relatively small cost impacts. We estimate the cost of system improvements, 

including indirect costs, to be less than $17 (MY2017 cost in 2011$) per vehicle, 

for all vehicle classes. This incremental cost reflects the cost of moving to lowpermeability materials, reduced number of fuel-system connections, longer 

contiguous lengths of plumbing, and low-permeation connectors. We believe that 

learning is also appropriate for evaporative emissions control systems as described 

above and in more detail in Chapter 2 of the RIA. 

We have used the individual technology costs discussed briefly here and in 

more detail in Chapter 2 of the RIA to estimate package costs for each of the 

different gasoline and diesel engine types in the fleet (i.e., I4 passenger car, V6 

passenger car, etc.). We have then multiplied these package costs by the projected

sales estimates for the years 2017 and later. The projected sales estimates used, as 

noted earlier, represent the future fleet mix rather than today’s fleet mix. That fleet 

mix is discussed in more detail in Chapter 2 of the RIA. With these total annual 

costs, we then determined the sales-weighted average cost increase for all passenger 

cars, light trucks and heavy-duty vehicles. Table VII-4 below provides our 

estimates of the incremental cost per vehicle by model year for both tailpipe and 

evaporative emissions standards. These values reflect the total direct and indirect 

manufacturing costs as well as the appropriate learning-by-doing effects. As stated 

above, a large portion of the cost is incurred in the initial model years. Costs then 

continue to rise as the percentage of vehicles complying with the final standards 

increases through MY 2025. 
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We have estimated costs consistent with the fact that manufacturers would 

be required to start the phase-in of Tier 3 standards in MY2017 for vehicles under 

6,000 lbs GVWR and the expectation that MY2018 will begin the phase-in for 

vehicles greater than 6,000 lbs GVWR. Based on the declining fleet averages for 

cars and trucks, we have apportioned our estimates for full compliance across the 

phase-in years as a percentage of the final standard. Manufacturers will be required 

to move from a Tier 2 Bin 5 fleet average in MY2017 (for vehicles <6,000 lbs 

GVW). This results in a significant step in stringency. As a result, a large portion 

of the costs are expected to be incurred in the initial model years. Finally, 

manufacturers have the opportunity in MY2015 and MY2016 to earn Tier 3 credits 

by producing a fleet that is cleaner than the current Tier 2 requirements. While we 

expect that most manufacturers will earn credits, either by selling California 

vehicles as 50-state vehicles or by certifying existing vehicles to lower Tier 2 bins, 

we have not reflected these credits in our cost analysis. In that way, we believe that 

our cost estimates are conservative.

Table VII-4 Per Vehicle Technology Costs by Model Year (2011$) a

Model Year 2017 2018 2019 2020 2021 2022 2023 2024 2025

Passenger car $46 $51 $53 $57 $59 $63 $63 $64 $65

Light truck $0 $73 $78 $82 $86 $88 $87 $87 $86

Light-duty 

Combined $29 $59 $62 $66 $68 $72 $71 $72 $72

Class 2b $0 $44 $51 $60 $66 $75 $71 $70 $69

Class 3 $0 $33 $41 $49 $57 $65 $62 $61 $60

>14,000 pound 

HD $0 $10 $10 $13 $13 $16 $15 $15 $15

a Costs shown include costs for the Tier 3 standards on vehicles sold outside California and other 

states that have adopted LEVIII.

Total annual costs are shown below in Table VII-5. This table includes all 

costs associated with the final Tier 3 vehicle standards, i.e., both exhaust and 

evaporative emission standards. Also included are facility-related costs associated 

with the final requirements to conduct more PM testing on gasoline vehicles. 

(Additional detail regarding the PM facility costs are described in section 2.6 of the 

final RIA.) We show the facility costs in the year 2016 even though the program 

does not begin until 2017. These costs represent the construction costs that would 

be incurred before the first year of the standards in preparation for the testing efforts 
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that would be required. We have not made any changes to the costs per facility

upgrade relative to the proposal, and we present the details supporting our estimates 

in Chapter 2 of the final RIA.

Lastly, as noted above, we have included the impact on operating costs 

associated with the new evaporative emission controls. Because the evaporative

emissions that would have been emitted absent the new standards will ultimately be 

used to propel the vehicle, the avoided evaporative emissions represent a savings to 

the consumer. While these savings are small on a per-vehicle basis—generally less 

than $2/vehicle over its lifetime—they are notable on a fleetwide basis where, in 

calendar year 2025, they result in $11 million in pre-tax savings. We also 

considered other operating costs, such as maintenance costs and repair costs, but 

concluded that the nature of the Tier 3 compliance technologies will not result in 

any increases or decreases in existing operating costs. We present the details about 

these operating savings in Chapter 2 of the final RIA.

Table VII-5 Annual Costs of the Tier 3 Vehicle Program (Millions of 2011

Dollars)a

Year

Exhaust Evap Operating b

Facilities Total LD HD All LD HD All LD HD All

2016 $0 $0 $0 $0 $0 $0 $0 $0 $0 $21.4 $21.4

2017 $268 $0 $268 $25.5 $0 $25.5 $0 $0 $0 $3.52 $297

2018 $519 $20.2 $539 $70.2 $3.24 $73.4 -$1.17 -$0.047 -$1.22 $3.52 $615

2019 $555 $24.2 $579 $69.2 $3.18 $72.4 -$2.03 -$0.094 -$2.12 $3.52 $653

2020 $571 $27.8 $599 $94.3 $4.12 $98.4 -$3.22 -$0.160 -$3.38 $3.52 $697

2021 $598 $31.5 $630 $92.8 $4.04 $96.8 -$4.44 -$0.226 -$4.67 $3.52 $725

2022 $605 $34.8 $640 $116 $4.93 $121 -$5.96 -$0.309 -$6.27 $3.52 $758

2023 $606 $33.3 $639 $111 $4.73 $116 -$7.45 -$0.390 -$7.84 $3.52 $751

2024 $620 $33.1 $653 $109 $4.70 $114 -$8.95 -$0.472 -$9.42 $3.52 $761

2025 $635 $32.8 $668 $108 $4.66 $113 -$10.4 -$0.553 -$11.0 $3.52 $773

2030 $632 $31.8 $664 $108 $4.56 $113 -$18.0 -$0.959 -$19.0 $3.52 $761

a Costs shown include costs for the Tier 3 standards on vehicles sold outside California and other 

states that have adopted LEVIII.

b Operating costs use pre-tax fuel prices; negative cost values denote savings.

B. Estimated Costs of the Fuel Program

The sulfur control program we are adopting is expected to result in many

refiners further investing in sulfur control hardware and changing the operations in 

their refineries to reduce their gasoline sulfur levels. The final sulfur control 

program requires refiners and importers to reduce their gasoline sulfur levels on 

average down to 10 ppm. The ABT provisions being adopted along with the 10

ppm average sulfur control standard will allow refiners that reduce their gasoline 

sulfur levels below 10 ppm to earn credits and trade those credits to other refiners 
Page 456 of 529

who would find it more expensive to reduce their sulfur levels down to the average 

standard. The ABT program will allow refiners to optimize their investments, 

which we believe will result in achieving the average sulfur control standard 

nationwide at lower costs. We are maintaining the current 80 ppm sulfur cap at the 

refinery gate. We estimate that the national average refinery costs incurred to 

comply with the fully phased-in Tier 3 sulfur control program with ABT program 

will be 0.65 cents per gallon, averaged over all gasoline. This estimate includes the 

capital costs, which are amortized over the volume of gasoline produced. 

In this section we summarize the methodology used to estimate the costs of 

Tier 3 sulfur control and our estimated costs for the program. A detailed discussion 

of all of these analyses is found in Chapter 5 of the RIA. 

1. Overview 

The basic methodology we used to estimate the cost of sulfur control for the 

final rule is similar to that for other rulemakings. Using a refinery-by-refinery cost 

model that we developed for this rulemaking, we projected the sulfur control 

technology expected to be used by each refinery, and the cost of each refinery’s 

sulfur control step, to estimate compliance with the final sulfur control program. 

We aggregated the individual refinery costs to develop a national average cost 

estimate for the final sulfur control program. We modeled costs assuming an in-use 

average of 10 ppm and assuming refiners take full advantage of the ABT provisions 

and minimize overcompliance based on experience for the Tier 2 program 

demonstrating this today. 

Refinery-by-refinery cost models are useful when individual refineries are 

expected to respond to program requirements in different ways and/or have 

significantly different process capabilities. Furthermore, as is the case with sulfur 

control, such approaches are possible when the refinery changes required are 

primarily “add-ons” that do not impact the fundamental operation at the refinery. 

Thus, in the case of modeling potential gasoline sulfur control programs, we needed 

a model that could accurately simulate the variety of decisions refiners will make at 

different refineries, especially in the context of a nationwide ABT program. For 

this and other related reasons, we developed a refinery-by-refinery cost model to 

evaluate the costs and other impacts of the final sulfur control program.

Refinery-by-refinery cost models have been used in the past by both EPA 

and the oil industry for such programs as the Mobile Source Air Toxics gasoline 

benzene control542, highway and nonroad diesel fuel sulfur standards. They are a 

proven means for estimating the cost of compliance for fuel control programs. 

While they will never precisely model and predict individual refinery operations 

and impacts, they provide both a good assessment of the overall market impacts and 

 

542 “Control of Hazardous Air Pollutants From Mobile Sources,” 72 FR 8428, February 26, 2007.
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of the variation of impacts across the refineries. Refinery-by-refinery models are 

also very useful when estimating the cost impacts of ABT programs.

We used a linear program (LP) cost model to estimate a cost for recovering 

the octane lost when refiners further desulfurize their gasoline to comply with the 

10 ppm sulfur standard. Our refinery modeling run for estimating octane cost 

assumed E10 with a small amount of E85. This cost is a key input into the refineryby-refinery cost model. The octane cost we developed from the LP model is $0.31 

octane number-barrel. We also used the LP refinery model to estimate the change in 

gasoline qualities that occurs when refiners make up for the lost octane that were 

used as inputs into the emissions impacts analysis discussed in Section III.

2. Methodology 

The way that the refinery-by-refinery cost model works can be subdivided 

into two primary steps. First, the model attempts to model how refiners blend up 

gasoline at each of their refineries. This is an important step because the fluidized 

catalytic cracker (FCC) naphtha, a product from FCC units, is responsible for 

almost all the sulfur in gasoline, even after complying with Tier 2. To help our 

understanding of how refiners blend up their gasoline, we used refinery unit 

throughput data which tell us how refiners are using their refinery units. The pergallon cost is calculated over all the gasoline pool, while the desulfurization cost is 

incurred by desulfurizing FCC naphtha; thus, the relative volume of FCC naphtha to 

the rest of the gasoline pool is important. 

The second primary step of the refinery-by-refinery cost model is to project 

how refiners would comply with the Tier 3 10 ppm average sulfur standard taking 

into consideration how they complied with the 30 ppm Tier 2 gasoline sulfur 

standard. To determine how refiners would comply with Tier 3, we contacted the 

vendors which provided the technology to refiners for complying with Tier 2 and 

continued to provide onsite support. Vendors provided information to us for 

installing grassroots units or revamping existing FCC postreaters sufficient to 

reduce the gasoline pool down to 10 and 5 ppm. We also evaluated the need and 

cost to refiners to reduce the sulfur levels of other refinery streams and included 

costs for those refineries to hydrotreat the light straight run naphtha stream where 

such additional control appeared warranted. Finally, we assessed the cost for 

complying with Tier 3 assuming that refiners take advantage of an ABT program. 

To assess the costs for the Tier 3 program that included an ABT program, we 

organized the estimated sulfur reduction costs for each refinery for achieving both 5 

and 10 ppm from lowest to highest to determine the set of investments for Tier 3 

which minimized the cost of the Tier 3 program.

We made a number of modifications to the refinery-by-refinery model for 

the final rule cost analysis. Based on a review of credit trading occurring for Tier 2, 

which revealed that credits are freely traded between refining companies, we 

changed our cost analysis to assume nationwide credit trading instead of restricting 

it to intra-company trading, as we did for the Tier 3 proposal’s cost analysis. We 
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incorporated refinery unit throughput data that we obtained from EPA’s Office of 

Air Quality Planning and Standards (OAQPS). The refinery model we used for this 

final rule estimated sulfur reduction cost for each refinery based on actual starting 

sulfur levels, instead of assuming that each refinery was desulfurizing their gasoline 

from 30 ppm to 10 or 5 ppm. We further refined our assessment for treating light 

straight run naphtha, but did not include any costs for treating butane since we 

found out from a vendor that butane is routinely treated today. We requested and 

received additional desulfurization cost data from vendor companies that we 

applied in our cost analysis. In response to comments from peer reviewers and 

other information that we obtained, we applied a higher offsite factor and a higher 

contingency factor to the capital costs. Additional changes that were made for the 

final rule cost analysis are discussed in Chapter 5 of the RIA. 

Our refinery-by-refinery sulfur cost model incorporates data on throughput 

volumes for each of the major refinery units in each refinery, including the crude 

unit, FCC unit, coker, hydrocracker, alkylation unit, reformer, isomerization unit, 

naphtha hydrotreater and aromatics plant. Unlike the unit capacity data used for the 

NPRM analysis, throughput volumes are a much more robust set of data because 

they eliminate the need to try to estimate how that refinery is operating that unit, or 

whether the unit is shutdown. We also used purchase and sales information for 

each refinery such as purchases of natural gas liquids, naphtha and sales of 

propylene. The propylene sales data were used to estimate whether a refinery is 

operating its FCC unit in propylene maximization mode. If a refinery is operating 

in propylene maximization mode, some of the volume of FCC naphtha is cracked to 

produce increased volume of propylene for sales to the chemicals industry, but 

these refineries are producing a smaller volume of FCC naphtha. While the 

increased use of refinery-specific data has improved the ability of the refinery-byrefinery model to represent the operations of each refinery, there still is uncertainty

about how each refinery is being operated. 

To assess how well our refinery model estimates the gasoline production for 

each refinery, we compared the gasoline production volume estimated by the 

refinery-by-refinery model for each individual refinery to the 2011 gasoline 

volumes reported by refiners to EPA. Despite the use of very robust throughput 

data, there was still an overproduction of gasoline by quite a few refineries. In 

trying to address this overproduction of gasoline volume by our refinery model, we 

spoke to refiners, vendors and peer reviewers and also reviewed the results of our 

LP refinery modeling runs. This led us to conclude that this volumetric difference 

in the refinery model was due in many cases to not accounting for the undercutting 

of heavy gasoline into the jet and diesel fuel pools. We further discuss the 

implications of undercutting in Section VII.B.3. Overall, after we made some 

adjustments by assuming that certain refiners are undercutting heavy gasoline to 

distillate, we were satisfied with the model’s volumetric estimates. To set up the 

refinery model, the model was updated with a projection of refined product 

volumes, and of input and output prices, from the Energy Information 

Administration’s Annual Energy Outlook (AEO) 2013 for the year 2018. 
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For this refinery-by-refinery sulfur cost model, we conducted two sets of 

independent peer reviews. One set of peer reviews was conducted for the version of 

the refinery-by-refinery model we developed for estimating the costs for the 

NPRM. We reviewed the peer review comments and decided that the impact on the 

estimated costs would be small, so we deferred making changes to address those 

peer review comments until the final rule. We developed another version of the 

refinery-by-refinery cost model which addressed the comments we received from 

the first set of peer reviews, as well as included additional improvements to the 

refinery model based on new information that we received after we conducted the 

cost analysis for the NPRM. We submitted the final rule version of the refinery

cost model for a second round of peer review. The peer review comments as well 

as our responses to these comments are contained in the docket. We addressed 

many of the comments made by the peer reviewers in the final version of the cost 

model. The oil industry has also conducted a similar analysis using a refinery-byrefinery cost model, and we discuss the results of its analysis at the end of this 

chapter. 

Our assessment of how refiners will comply with Tier 3 has not changed 

since we conducted our cost analysis for the NPRM. The refinery unit responsible 

for the greatest contribution of sulfur to gasoline is the FCC. The FCC processes a 

very heavy feedstock which contains high levels of sulfur.543 When the FCC cracks 

this heavy, sour feedstock, a portion of the sulfur in the feed to the FCC ends up in 

the FCC naphtha, an important gasoline blendstock stream.544 Before the Tier 2 

sulfur control program was implemented, FCC naphtha contributed over 95 percent 

of the sulfur to a refinery’s gasoline, and now that Tier 2 has been fully 

implemented it still contributes roughly 80 to 90 percent of the sulfur in refiner’s 

gasoline for those refineries with FCC units. To comply with the Tier 2 sulfur 

control program, most refiners installed FCC naphtha hydrotreaters (FCC 

postreaters) and some refiners installed FCC feed hydrotreaters (FCC pretreater) to 

reduce that unit’s sulfur contribution to their gasoline pool. The technologies 

installed include Axens Prime G+, Exxon-Mobil Scanfining, CDTech’s CDHydro 

and CDHDS, Sinopec’s S-Zorb and UOP’s ISAL (UOP now offers a postreating 

technology named Selectfining). Despite the much lower sulfur contribution to the 

gasoline pool by the FCC after complying with Tier 2, the vendors which supplied 

sulfur control technology for complying with the Tier 2 sulfur control program have 

informed us that to comply with a more stringent sulfur standard, refiners are 

expected to further reduce the sulfur in the FCC naphtha. We contacted each of 

those technology vendors, and some of them provided information useful to 

estimate the cost of lowering the sulfur in the FCC naphtha to allow each refinery to 

reduce the sulfur in its gasoline to 10 ppm. We also reviewed literature that is 

 

543 A hydrocarbon stream which contains large amounts of sulfur is also referred to as being sour. In 

general, the heavier the hydrocarbon portion of crude oil, the higher the natural sulfur content.

544 On average, the fluidized catalytic cracker supplies about 35 percent of a refiner’s gasoline 

output.
Page 460 of 529

available on the Web to further understand what would be involved to achieve a 10

ppm sulfur standard using postreating (see Chapter 4 of the RIA). We were able to 

obtain some additional sulfur cost information from the vendors since we conducted 

our cost analysis for the proposed rule, and this was incorporated into our cost 

analysis.

Gasoline desulfurization vendors were pessimistic that the operations of 

FCC pretreaters could be adjusted to enable those refineries which relied on those 

units to comply with the Tier 2 sulfur standard to meet a 10 ppm sulfur standard. 

Many of those FCC pretreater units have marginal (less than two years) turnaround 

times today and they would either require a major revamp or suffer even shorter 

turnaround times if they were to simply be turned up. For the refineries solely

relying on FCC pretreaters to comply with Tier 2, desulfurization vendors project 

that most refineries in this situation will put in grassroots FCC postreaters to allow 

those refineries to comply with a 10 ppm gasoline sulfur standard. However, since 

adding grassroots FCC postreaters is relatively expensive for the amount of sulfur 

reduction obtained, the ABT analysis we conducted avoided many of these types of 

investments. Instead, the refiners with refineries in this situation are projected to 

acquire credits from refiners capable of reducing sulfur levels below 10 ppm at a 

lower cost.

In addition to addressing the sulfur in the FCC naphtha, we believe that 

some refineries may need to reduce the sulfur in the light straight run (LSR) 

naphtha. Most refiners hydrotreat the LSR before sending that stream to an 

isomerization unit, and therefore that stream is very low in sulfur. Other refiners 

use a sweet crude oil, and once the LSR is treated by using an extraction 

desulfurization technology, the sulfur level of the LSR is likely to be very low 

(under 10 ppm). However, some refineries that refine a more sour crude oil slate

and do not have isomerization units could have fairly high sulfur levels in their 

LSR, even after using extraction desulfurization. For these refineries, we conducted 

an assessment to determine whether these refineries have sufficient hydrotreating 

capacity to hydrotreat the LSR. We believe that refiners that do not currently

desulfurize their LSR, but may need to do so because their crude oil is not sweet,

could do so by either feeding it to their naphtha hydrotreater (the hydrotreater which 

desulfurizes the feed to the isomerization and reformer units), or perhaps even to 

the FCC postreater; we added a cost for this. Because LSR does not contain any

olefins, it is an easy stream to hydrotreat and actually improves the hydrotreating 

conditions within the FCC naphtha hydrotreater. 

3. Fuel Program Costs 

We used the refinery-by-refinery cost model to estimate the costs of the 10 

ppm average standard being adopted in this final rule. The Tier 3 fuels program 

maintains the 80 ppm cap sulfur control standard that was put in place under the 

Tier 2 sulfur program. In general, the cost model indicates that further 

desulfurizing the FCC naphtha will be the most cost-effective means for achieving 

sulfur control. We accounted for additional costs to refiners for desulfurizing their 
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LSR naphtha, for those refineries where we estimate that the LSR naphtha is not 

being desulfurized today and found that it likely needs to be. 

As described in Section V.A.4, we are also adopting an ABT program that is 

designed to ease the overall burden on the industry while still achieving the 10 ppm 

annual average sulfur standard for the nation as a whole. Under the ABT program, 

refineries that can reduce sulfur below 10 ppm at a relatively low cost can generate 

credits which can then be acquired by refineries for whom the cost of attaining the 

10 ppm sulfur standard would be higher. These credits can be traded among 

refineries within the same company, or between refiners and importers nationwide. 

The net effect of this credit trading would be to reduce the overall cost of the 

program. The extent to which the ABT provisions reduce the cost of the Tier 3 

program depends on the extent that the ABT program is used by refiners. As 

summarized in the alternatives section (Section IX), the cost of the 10 ppm Tier 3 

sulfur program is 0.65 c/gal assuming widespread nationwide credit trading, while 

if we assume that no credit averaging or trading between any individual refinery

occurs, the Tier 3 program cost increases to 0.88 c/gal, a 35% increase. In between 

those two scenarios is the case that sulfur credits are only used for averaging within 

companies (not traded between refineries owned by different companies), and we 

estimated the cost for that scenario at 0.75 c/gal. Since we were not sure about the 

extent that credits were traded under Tier 2 when we conducted the cost analysis for 

the NPRM, we conservatively assumed for the NPRM cost analysis that refiners 

would only volume-average sulfur levels among their refineries, and not trade 

credits between refining companies. However, for the final rule cost analysis we 

evaluated the credit trading that was occurring under Tier 2. We found that 56% of 

credits were in fact being traded between refining companies under Tier 2, with the 

balance being used within refining companies. This demonstrated that credit 

trading was freely occurring between refining companies, supporting the conclusion 

that credit trading would occur nationwide among refineries under Tier 3. We 

therefore assumed nationwide credit trading for our final rule.

To estimate the impact that the ABT program could have on nationwide 

average fuel costs, we began with the refinery-by-refinery costs described in 

Section VII.B.2.b for sulfur reductions down to either 10 ppm or 5 ppm. We then 

determined the lowest cost option among three alternatives for each refinery:

1. The refinery reduces its sulfur to 10 ppm.

2. The refinery reduces its sulfur to 5 ppm and generates credits for the 

increment between 10 ppm and 5 ppm.

3. The refinery does not lower sulfur, but instead relies on the purchase of 

credits to comply with the 10 ppm standard.

A fourth category applied to refineries whose average gasoline sulfur levels 

are already below 10 ppm (their refineries do not have FCC units). All such 
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refineries were assumed to generate credits for the increment between 10 ppm and 

their current sulfur level.

Our methodology was unable to consider a fifth category where a refinery

may utilize less expensive capital and operational changes to reduce their sulfur 

levels partially below Tier 2 levels and rely on purchasing credits only for the 

remainder. Such opportunities are likely to exist at most refineries, but such 

refinery specific information is not available to us. As a result, refineries in the 

third category are modeled to simply remain at Tier 2 sulfur levels and incur no 

capital or operating cost.

To simplify the modeling of how an ABT program might operate, we 

focused on the circumstances that refineries would face in the longer term, 

specifically after 2020. This approach meant that the ABT program modeling did 

not consider the impact on gasoline sulfur levels of delayed compliance for small 

refiners and small volume refineries, nor did it consider the generation and use of 

any early sulfur credits. Moreover, our ABT modeling considered only gasoline 

sold for use outside of California, and only gasoline produced by domestic 

refineries (not importers).

Our final rule cost analysis is based on a nationwide credit trading scenario. 

Under Tier 2 today, a significant fraction of Tier 2 sulfur credits are bought and 

sold between companies and we believe that this practice will continue (see Section 

V.D for details about the ABT program). To model this phenomenon, we first 

establish an estimated cost for each refinery for reducing its gasoline sulfur down to 

10 ppm and to 5 ppm. Next we ranked the sulfur control strategies for all the 

refineries in order from lowest to highest sulfur control cost per gallon of gasoline 

and estimated the impact of their projected sulfur control strategies on refinery

sulfur levels using only one cost (either 10 or 5 ppm) for any one refinery. The 

model then follows this ranking, starting with the lowest-cost refineries, and adds 

refineries and their associated control technologies one-by-one until the projected 

national average gasoline sulfur level reaches 10 ppm. This modeling strategy

projects the sulfur control technology that will be used by each refinery, as well as 

identifies those refineries that are expected to generate credits and those that are 

expected to use credits in lieu of investing in sulfur control. The sum of the costs of 

the refineries expected to invest in further sulfur control provides the projected 

overall cost of the program. 

Based on the results of our cost analysis, we estimate that for the U.S.

refining industry to achieve a 10 ppm average level with the full benefit of 

nationwide credit trading, the final sulfur control program would cost on average 

0.65 cents per gallon when it is fully phased in, assuming that capital investments 

are amortized at a seven percent return on investment before taxes and expressed in 

2011 dollars. Refiners would be expected to make $2.025 billion in capital 

investments to achieve this sulfur reduction. These capital investments are 

expected to be made over the 6 years that the Tier 3 program is expected to be 
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phased in, which would spread out the capital costs to average about $330 million 

per year.

Our cost assessment is likely conservative (i.e., overestimates costs). The 

capital cost estimate is based on vendor data which assumes that refiners are 

hydrotreating full range FCC naphtha. If refiners are indeed undercutting their FCC 

naphtha at many refineries (and more will be doing so in the future), many refiners 

would likely not need to make any capital changes. This is because the FCC 

postreaters were designed when refiners were maximizing their gasoline production 

and hydrotreating full range FCC naphtha. When undercutting the FCC naphtha to 

the diesel pool, refiners cut out about 16% of the FCC naphtha volume and about 

half of the sulfur. Thus, if a refiner was able to produce 30 ppm gasoline, after fully 

undercutting their FCC naphtha into the diesel pool, they would likely be able to 

produce 15 ppm sulfur gasoline using their existing Tier 2 postreater. They could 

then use a more active catalyst which likely would enable the refinery to achieve 10 

ppm gasoline without any capital changes to their FCC postreaters. If all refiners 

were undercutting their FCC naphtha and are able to comply with Tier 3 without 

any capital additions to their FCC postreaters, the cost of the program would 

decrease to around 0.4 c/gal. 

Another way that our modeling could be conservative is that refiners are 

slowly converting their FCC pretreaters over to mild hydrocrackers to produce more 

diesel fuel, which is in higher demand. We do not know the extent that this is 

happening, and our current analysis assumes that none of the FCC pretreaters have 

been converted over to mild hydrocrackers. However, a cost sensitivity analysis 

that we conducted with our refinery model estimates that if all the FCC pretreaters 

were converted over to mild hydrocrackers, costs of the Tier 3 program would 

decrease to 0.55 c/gal, assuming nationwide credit trading. If we combined the cost 

reduction of undercutting with the mild hydrocracking, the Tier 3 costs would be 

lower than either of two cost sensitivities which were conducted independently.

We also received some comments by API and two of the peer reviewers 

about our octane costs. We will not include all the discussion here about octane 

costs because we do so in detail in the response to peer review comments and in 

Chapter 5 of the RIA. While we are comfortable with the octane costs that we used, 

we did conduct a sensitivity at a higher octane cost ($0.5/per octane number barrel 

instead of $0.31/octane number-barrel that we used). At the higher octane cost of 

$0.5/octane number barrel, the Tier 3 sulfur control costs increases from 0.65 c/gal 

to 0.73 c/gal. 

We also estimated annual aggregate costs, including the amortized capital 

costs, associated with the new fuel standard. When the 10 ppm gasoline sulfur 

standard is fully phased in 2020, we estimate that the sulfur standard would cost 

$790_ million in that year. Figure VII-1 shows the distribution of refinery costs 

over the accumulated gasoline volume for the fully phased in 10 ppm sulfur 

standard.
Page 464 of 529

Figure VII-1 Tier 3 Sulfur Control Costs

Figure VII-1 shows that for almost 20 percent of the gasoline pool, 

refineries will not incur any cost under Tier 3, either because these refineries are 

already very low in sulfur because they do not have FCC units, or because the 

refineries are purchasing credits.545 For another 10 percent of the gasoline pool, the 

refinery costs are in the 0 – 0.5 cent/gal range. For the next 55 percent of the 

gasoline pool, the refinery costs are in the 0.5 – 1.0 c/gal range. For the last 15 

percent of the gasoline pool, the refinery costs range from 1.0 to 2.1 c/gal for 

revamps, with the exception of one refinery at 2.8 c/gal representing the cost for the 

sole grassroots unit which our modeling estimates would need to be installed. All 

other refiners that may otherwise need to install a grassroots hydrotreater were able 

to comply more cheaply through the purchase of credits. 

Figure VII-2 summarizes our estimated U.S. gasoline sulfur levels over the 

accumulated gasoline volume post Tier 3. 

 

545 Refineries purchasing credits will incur a cost for the purchase of the credit, but since we do not 

know what the price of a credit will be, we allocate all the cost for complying with Tier 3 solely on 

the refineries adding capital and incurring operating costs to comply with Tier 3.
Page 465 of 529

Figure VII-2 Estimated U.S. Gasoline Sulfur Levels Post Tier 3

Figure VII-2 shows that over 80 percent of the gasoline pool would 

predominately be either 5 or 10 ppm representing the two sulfur levels to which we 

assumed that refiners would desulfurize their gasoline pool. For the rest of the 

gasoline pool, the refineries are clearly purchasing credits and their sulfur levels 

range from 10 to nearly 70 ppm. As discussed earlier, lacking more detailed 

refinery-specific information, for these refineries we assumed that they take no 

action to reduce their gasoline sulfur below their Tier 2 levels. In reality these 

refineries are likely to take some very cost-effective steps to partially reduce their 

gasoline sulfur and not rely solely on credits to demonstrate compliance with Tier 3. 

Were we able to model such refinery changes, it would only serve to further lower 

our projected costs. 

4. Other Cost Estimates

Three other cost studies were conducted to estimate the cost of additional 

reduction in gasoline sulfur. All of these studies show average costs of less than 2 

cents per gallon. 

One of these studies was conducted in October 2011 by the International 

Council for Clean Transportation (ICCT). 546 ICCT retained Mathpro for this 

 

546 Mathpro (October 2011). Refining Economics of a National Low Sulfur, Low RVP Gasoline 

Standard, Performed for The International Council for Clean Transportation, Available at: 

http://www.theicct.org/sites/default/files/publications/ICCT04_Tier3_Report_Final_v4_All.pdf. 

Accessed December 12, 2011. 
Page 466 of 529

analysis. ICCT had Mathpro analyze a 10 ppm average gasoline sulfur standard in 

PADDs 1 – 4 (generally speaking, PADDs 1 – 4 represents the part of the U.S. east 

of, and including, the Rocky Mountain states). The cost presented by ICCT is that 

complying with a 10 ppm average sulfur standard would cost refiners on average 

0.8 cents per gallon. This cost was calculated based on a before-tax 7 percent return 

on investment, the same capital amortization basis that we use for our cost analysis. 

The cost of a 10 ppm average gasoline sulfur control standard estimated by ICCT is 

very close to our cost estimate. 

API retained Baker and O’Brien to study the cost of additional sulfur control 

using a refinery-by-refinery cost approach with Baker and O’Brien’s Prism 

model.547 API studied a 10 ppm average gasoline sulfur standard, however, API

included a very stringent 20 ppm cap standard which did not allow for an ABT 

program to optimize refinery investments and minimize overall costs (an estimate 

of the impact of the 20 ppm cap standard using API information is presented 

below). 

API made a series of conclusions based on the study. Perhaps the most 

important conclusion is that no refinery would shut down as a result of the 10 ppm 

gasoline sulfur control standard, even though API did not study the flexibilities of 

an ABT program and used excessively high capital costs for a grassroots FCC 

postreater (see below). API did not report average costs, but reported the marginal 

costs for the cost study. Marginal costs reflect the cost of the program to the 

refinery or refineries which would incur the highest costs, assuming that the highest 

cost refineries would set the price (or in this case, the price increase) of gasoline. 

Since they assumed a 20 ppm cap precluding refiners from utilizing the ABT 

program, it required virtually all refiners to incur capital costs thereby driving up 

marginal costs. The report concluded that marginal costs after the imposition of a 

10 ppm gasoline sulfur program would increase the price of gasoline by 6 to 9 cents 

per gallon in most markets. API did not define how its statement “in most markets” 

would apply to the U.S. gasoline supply. API also did not provide any justification 

why it assumed that the refineries that would experience the highest desulfurization 

cost under Tier 3 would also be the same refineries which set the gasoline price in 

the gasoline market today. 

Although API did not provide an average gasoline desulfurization cost in its 

report, we could calculate an average cost based on the gasoline volume and total 

annual costs provided. The total cost reported in the report for the 10 ppm average 

gasoline sulfur standard is $2390MM/yr and the non-California gasoline volume is 

7343 thousand barrels per day. This results in an average per-gallon desulfurization 

cost of $0.89/bbl or 2.12 c/gal. The difference between the average cost and 

 

547 Baker and O’Brien, Addendum to Potential Supply and Cost Impacts of Lower Sulfur, Lower 

RVP Gasoline; prepared for The American Petroleum Institute. March 2012. Available at: 

http://www.api.org/Newsroom/upload/110715_LowerSulfur_LowerRVP_Final.pdf. 
Page 467 of 529

marginal cost (price increase) that API is projecting is profit. Thus, API’s analysis 

would suggest that the oil industry would profit from 10 ppm low sulfur standard by 

roughly 4 to 7 cents per gallon, or roughly $4 to $8 billion dollars per year as a 

result of gasoline sulfur control. 

The average cost of the 10 ppm average gasoline sulfur standard described 

above was calculated using API’s methodology for amortizing capital investments. 

To assess the costs consistent with OMB’s guidance for our rulemakings and to

allow a direct comparison between the API cost study and our cost study, we 

adjusted the API costs to be on a similar basis as our costs. We adjusted the API 

costs to reflect a before-tax 7 percent return on investment (ROI) for capital 

invested for the hydrotreaters and hydrogen plants instead of the after-tax 10 

percent ROI used by API. This lowered the API estimated costs from 2.12 c/gal to 

1.58 c/gal. API’s 1.58 cents per gallon cost is still higher than our 0.65 c/gal cost 

with an ABT program that assumes nationwide trading of credits, and higher than 

our 0.86 c/gal for the case which assumes no ABT program. The remaining 

difference between our estimated costs and those by API are driven by API’s 

assumptions for the capital costs that would be incurred for adding grassroots FCC 

postreaters, or revamping existing ones. 

While little detail is provided by API about what hardware comprises their 

desulfurization units, the inside battery limits (ISBL) and total capital costs for the 

FCC postreaters and FCC pretreaters are provided in API’s report. API’s FCC 

pretreaters capital costs are consistent with the capital costs that we have used for 

this unit. However, the FCC postreater costs used by API are much higher than 

what we used and have been used in the past by others. API’s capital cost for a 

grassroots FCC postreater is $228 million for a 35,000 bbl/day unit, or $6540 

per/bbl per day. API’s capital cost includes the outside battery limit (OSBL) costs. 

We were able to obtain a document which shed some light on the 

methodology that API used to develop its FCC postreater capital costs.548 When the 

proposed rule was being reviewed by the Office of Management Budget (OMB) at 

the end of 2012, API provided to OMB a document which provided answers to 

questions that EPA and EIA posed to API and Baker and O’Brien back in mid-2011 

when API was about to release its study of gasoline sulfur control costs. According 

to the document, API collected investment cost information for 5 FCC naphtha 

hydrotreater projects that were apparently completed by refiners to comply with 

Tier 2, and not the low severity capital projects that refiners would use to comply

with Tier 3. No specific information was provided for any of those projects to 

determine whether each of those projects was typical, or if they included atypical 

costs add-ons for other refinery upgrades, which is common when refiners make 

changes in response to an environmental regulation. API adjusted the capital cost 

 

548 Document entitled “Follow-up Questions from EPA-EIA” (no other information provided on the 

document).
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to be on a 35kbbl/day basis and the capital costs were inflated from the year that the 

project was constructed in the 2003 to 2005 timeframe, to mid-2009 dollars using 

the Nelson-Farrar Refinery Construction Index. API then reviewed the final capital 

investment costs for FCC postreaters with several other members that had recently 

installed FCC postreaters. One refiner which had presented an itemized list of 

capital costs for a recent FCC postreater installation stated that the costs for their 

recent FCC postreater installation were two times higher than the Nelson-Farrar 

adjusted costs, so API doubled the costs. The information provided did not state 

whether these later installations used to double the estimated postreater costs were 

in the U.S. where engineering and construction are readily available or overseas 

where most recent FCC postreater installations have been occurring and where the 

installation costs could be much higher.

In contrast, the ISBL capital cost that we used for a grassroots FCC 

postreater is $1500/bbl-day for a 30,000 bbl/day grassroots unit, which increases to 

$2430/bbl/day when the offsite and contingency costs are added on. Thus, the API

capital costs of $6540 are about 2 and one half times higher than the capital costs 

that we are using for a grassroots FCC postreater. To check our capital costs, we 

found other capital cost estimates to which we could compare our costs, including 

the capital costs used by the National Petroleum Council when it studied the cost of 

gasoline desulfurization prior to Tier 2. Compared to the average of the rest of the 

capital cost estimates, the API capital cost for FCC postreater is about four times 

higher. Compared to the next highest cost estimate, which is the FCC postreater 

capital cost from the Jacobs data base in the Haverly refinery cost model that we 

use,549 the API capital costs are almost two times higher. 

As alluded to earlier, an important distinction must be made with respect to 

the severity of desulfurization for the capital cost comparison made for complying 

with Tier 2 versus Tier 3. For complying with the Tier 2 gasoline sulfur standard 

(Jacobs and NPC costs), a typical refinery would have installed an FCC postreater 

to desulfurize the FCC naphtha from about 800 ppm down to about 75 ppm, a 725 

ppm, or a 91 percent sulfur reduction. In the case of a grassroots postreater that 

would be installed for Tier 3, the postreater would treat FCC naphtha already low in 

sulfur due to the pretreater installed before the FCC unit (these refineries are 

currently complying with Tier 2 using an FCC pretreater). Thus, the new grassroots 

FCC postreater would only have to reduce the FCC naphtha from 100 ppm to 25 

ppm, a much smaller 75 ppm or 75 percent sulfur reduction. A grassroots FCC 

postreater installed for Tier 2 would typically remove 10 times more sulfur than one 

installed for Tier 3. This is important because a significant portion of the FCC 

postreater capital cost is devoted to avoiding the recombination reactions which 

occur when hydrogen sulfide concentrations are high and react with the olefins 

 

549 The installed capital cost for an FCC postreater from the Jacobs data base was adjusted to current 

year dollars. This estimated installed capital cost is several years old and may not represent Jacobs 

current cost estimate for a FCC postreater.
Page 469 of 529

contained in the FCC naphtha. Thus, a grassroots FCC postreater installed for Tier 

3 would be expected to be significantly lower in capital cost compared to a Tier 2 

FCC postreater. When API presented the costs, they stated that their grassroots 

capital costs were based on an actual installation for the Tier 2 program. This is 

likely one important reason why the capital costs used by API for its cost study of 

the Tier 3 program are so high. Another way to assess the API capital cost for the 

FCC postreaters is to compare it to the FCC pretreater cost that API is using. FCC 

pretreaters are much higher pressure units and use more expensive metallurgy than 

FCC postreaters and, for these two reasons, are much more expensive than FCC 

postreaters on a per-barrel basis. However, API’s FCC postreater capital costs are 

about 50 percent more expensive than its own FCC pretreater capital costs, which is 

inconsistent with the design requirements of the units. 

API’s estimated range of capital cost for revamping an FCC postreater is 

also higher than our range of capital cost for revamping an FCC postreater, when 

assessing the revamped costs as a percentage of the capital cost for a grassroots 

unit. API estimates that revamping an FCC postreater would cost 30 to 70 percent 

of the capital cost for a grassroots FCC unit. Our capital cost estimate for 

revamping an FCC naphtha postreaters range from 17 to 50 percent of the capital 

cost for a grassroots FCC postreater, however, most of the revamps are estimated to 

cost at the lower end of that range. 

As discussed above, an important reason why API’s projected capital costs 

for complying with Tier 3 are so high is that API assumed a 20 ppm cap standard in 

addition to the 10 ppm average standard that it studied. The 20 ppm cap standard 

eliminates the possibility of realizing the cost savings of an ABT program. After 

we proposed the Tier 3 rule, API presented to EPA, in its comments on the 

proposed rulemaking, its estimate for the cost of finalizing a more stringent cap 

standard. The study, which was contracted to the Turner, Mason & Company, 

estimated that a 20 ppm cap standard would increase the capital cost of complying 

with a 10 ppm average standard by $6.1 billion. If we subtract the $6.1 billion in 

capital costs attributed to the 20 ppm cap standard from the $9.8 billion in total 

capital costs from API’s Addendum report which estimated the cost of complying 

with Tier 3, and adjust the fixed operating costs accordingly, the API estimated 

average cost (not marginal cost) for complying with Tier 3 decreases to 0.97 c/gal. 

In addition to the questionable capital costs assumed for FCC postreaters as 

discussed above, this information from API on its estimated cost of complying with 

a 20 ppm cap standard helps to answer an important question of why API estimated 

average cost was still higher than the other studies after other cost adjustments were 

made. This final adjustment to the API costs makes the estimated API costs for 

complying with Tier 3 right in line with the other cost studies. This adjusted API

cost, however, still does include the cost saving aspects of credit averaging and 

trading since the API analysis assumed that each refinery meets the 10 ppm average 

sulfur standard. Thus, to compare this most recent cost adjustment of API costs to 

our cost study, our 0.87 c/gal cost for no ABT program would be the most 
Page 470 of 529

appropriate cost for comparison (see Chapter IX for alternative costs), The adjusted 

API cost and our cost are only 0.1 c/gal different.

Our assessment of the API study is supported by work performed by The 

Emissions Control Technology Association (ECTA) which retained personnel 

within Navigant Economics. That study assessed the costs of a 10 ppm average 

gasoline sulfur standard and also evaluated the ICCT and API cost studies.550 The 

authors made a number of conclusions. After reviewing both the ICCT and API

studies, the authors found that a primary difference in estimated costs between the 

two studies was the capital costs. The authors contacted vendor companies that 

license FCC postreater technologies and surveyed the companies to find out what 

the capital costs are for a FCC postreater. As a result of the survey, the report 

authors concluded that API’s capital costs were too high, and those used in the 

ICCT study were about right. The authors found that Baker and O’Brien has a 

history of exaggerating the economic impacts of EPA rules, citing the costs and 

other impacts of its analysis of the 2007 on-highway heavy-duty proposed 

rulemaking. The authors concluded that the impact of a 10 ppm gasoline sulfur 

standard on the average refining cost would likely be closer to the 1 cent per gallon 

estimate by the ICCT study. Furthermore, the report’s authors also pointed out that 

the marginal cost analysis conducted by API did not consider the averaging banking 

and trading (ABT) program that we adopted, which would reduce the marginal 

costs of the Tier 3 final rule.

C. Summary of Program Costs

While the estimated costs for the separate vehicle and fuel programs are 

presented in Sections VII.A and VII.B, respectively, it is useful to present the 

combined cost estimates representing the full Tier 3 program. 

We have chosen to use an annual cost format to represent the combined 

vehicle and program costs because this approach provides the most straightforward 

means for comparing vehicle costs to fuel costs, and for demonstrating the total cost 

impact of our final program. This approach to combined costs also provides a basis 

for comparing the program costs to the projected benefits as described more fully in 

Section VIII.

Table VII-6 below shows our estimated program costs by year. The total 

program costs for the final rule are lower than those projected for the proposal due 

to several reasons. First, the vehicle program costs are lower due in part to applying 

the per vehicle costs to vehicles excluding those sold in California and the states 

that have adopted the LEV III program. A complete discussion of the differences in 

vehicle costs between the proposal and final rule are outlined above in Section 

 

550 Schink, George R., Singer, Hal J., Economic Analysis of the Implications of Implementing EPA’s 

Tier 3 Rules, prepared for the Emissions Control Technology Association, June 14, 2012.
Page 471 of 529

VII.A.1. Second, the fuel program costs are also lower than the values projected for 

the proposal due to lower refinery cost estimates, as discussed above in Section 

VII.B. In addition, the annual fuel consumption projections are lower in the final 

rule because they reflect the inclusion of the Light-Duty Greenhouse Gas and Fuel 

Economy Standards for 2017-2025 model years. Complete details of this analysis 

can be found in the RIA Chapter 8.

Table VII-6 Total Annual Vehicle and Control Costs, 2011$

a

Year Vehicle 

Exhaust

Emission 

Control Costs

($Million)

Vehicle Evaporative 

Emission Control 

Costs

($Million)

Vehicle 

Operating 

Costs 

($Million)

Facility 

Costs 

($Million)

Fuel Sulfur 

Control Costs

($Million)

Total 

Program 

Costs 

($Million)

2016 $0 $0 $0 $21 $0 $21

2017 $268 $26 $0 $4 $804 $1,101

2018 $539 $73 -$1 $4 $799 $1,414

2019 $579 $72 -$2 $4 $794 $1,447

2020 $599 $98 -$3 $4 $787 $1,484

2021 $630 $97 -$5 $4 $778 $1,503

2022 $640 $121 -$6 $4 $768 $1,526

2023 $639 $116 -$8 $4 $758 $1,509

2024 $653 $114 -$9 $4 $748 $1,509

2025 $668 $113 -$11 $4 $737 $1,510

2030 $664 $113 -$19 $4 $696 $1,457

a These estimates include costs associated with: (a) the Tier 3 vehicle standards in all states except 

California and the states that have adopted the LEV III program; and, (b) the Tier 3 fuel standards in 

all states except California.

VIII.What are the Estimated Benefits of the Rule?

This section presents EPA’s analysis of the criteria pollutant-related health 

and environmental impacts that will occur as a result of the final Tier 3 standards. 

The vehicles and fuels subject to the standards are significant sources of mobile 

source air pollution such as direct PM, NOX, SOX, VOCs and air toxics. The 

standards will reduce exhaust and evaporative emissions of these pollutants from 

vehicles. Emissions of NOX (a precursor to ozone formation and secondarilyformed PM2.5), SOX (a precursor to secondarily-formed PM2.5), VOCs (a precursor 

to ozone formation and, to a lesser degree, secondarily-formed PM2.5) and directlyemitted PM2.5 contribute to ambient concentrations of PM2.5 and ozone. Exposure 

to ozone, PM2.5, and air toxics is linked to adverse human health impacts such as 

premature deaths as well as other important public health and environmental 

effects.
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For the final rulemaking, we have estimated the health and environmental 

impacts in 2030, representing projected impacts associated with a year when the 

program is fully implemented and when most of the fleet is turned over. Overall, we 

estimate that the standards will lead to a net decrease in PM2.5- and ozone-related 

health impacts. The estimated decrease in population-weighted national average 

PM2.5 exposure results in a net decrease in adverse PM-related human health 

impacts (the decrease in national population-weighted annual average PM2.5 is 0.04

μg/m3in 2030). The estimated decrease in population-weighted national average 

ozone exposure results in a net decrease in ozone-related health impacts 

(population-weighted maximum 8-hour average ozone decreases by 0.32 ppb in 

2030).551

Using the lower end of EPA’s range of preferred premature mortality

estimates (Krewski et al., 2009 for PM2.5 and Bell et al., 2004 for ozone),552,553 we 

estimate that by 2030, implementation of the standards will reduce approximately

770 premature mortalities annually and will yield between $6.7 and $7.4 billion in 

total annual benefits, depending on the discount rate used.

554

 The upper end of the 

range of avoided premature mortality estimates associated with the standards (based 

on Lepeule et al., 2012 for PM2.5 and Levy et al., 2005 for ozone)555,556 results in 

approximately 2,000 premature mortalities avoided in 2030 and will yield between

$18 and $19 billion in total benefits. Thus, even using the lower end of the range of 

premature mortality estimates, the health impacts of the final standards presented in 

this rule are projected to be substantial.

We note that of necessity, decisions on the emissions and other elements 

used in the air quality modeling were made early in the analytical process for the 

final rulemaking. For this reason, the modeled changes in emissions used to 

 

551 Note that the national, population-weighted PM2.5 and ozone air quality metrics presented in this 

Section represent an average for the entire, gridded U.S. CMAQ domain. These are different than 

the population-weighted PM2.5 and ozone design value metrics presented in Chapter 7, which 

represent the average for areas with a current air quality monitor.

552 Krewski, D., M. Jerret, R.T. Burnett, R. Ma, E. Hughes, Y. Shi, et al. (2009). Extended followup and spatial analysis of the American Cancer Society study linking particulate air pollution and 

mortality. HEI Research Report, 140,Health Effects Institute, Boston, MA.

553 Bell, M.L., et al. (2004). Ozone and short-term mortality in 95 U.S. urban communities, 1987-

2000.Journal of the American Medical Association, 292(19), 2372-2378.

554 The monetized value of PM2.5-related mortality accounts for a twenty-year segmented cessation 

lag. To discount the value of premature mortality that occurs at different points in the future, we 

apply both a 3 and 7 percent discount rate. We also use both a 3 and 7 percent discount rate to value 

PM-related nonfatal heart attacks (myocardial infarctions). Nonfatal myocardial infarctions (MI) are 

valued using age-specific cost-of-illness values that reflect lost earnings and direct medical costs 

over a 5-year period following a nonfatal MI.

555 Lepeule J, Laden F, Dockery D, Schwartz J (2012). Chronic Exposure to Fine Particles and 

Mortality: An Extended Follow-Up of the Harvard Six Cities Study from 1974 to 2009. Environ 

Health Perspect. Jul;120(7):965-70.

556 Levy, J.I., S.M. Chemerynski, and J.A. Sarnat. (2005). Ozone exposure and mortality: an empiric 

bayes metaregression analysis. Epidemiology. 16(4), 458-68.
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support the air quality and benefits analyses are slightly different than those used to 

represent the final emissions impacts of the Tier 3 standards. The magnitude of the 

differences is small, however, and for that reason we do not expect these differences 

to materially impact our cost-benefit conclusions. See Chapter 7.2.1.1 of the RIA 

for more details.

A. Overview

We base our analysis of the program’s impact on human health on peerreviewed studies of air quality and human health effects.557,558

 These methods are 

described in more detail in Chapter 8 of the RIA. Our benefits methods are 

consistent with the RIA that accompanied the final revisions to the National 

Ambient Air Quality Standards (NAAQS) for Particulate Matter and the final ozone 

NAAQS. To model the ozone and PM air quality impacts of the final standards, we 

used the Community Multiscale Air Quality (CMAQ) model (see Chapter 7.2.2 of 

the RIA that accompanies this preamble). The modeled ambient air quality data 

serves as an input to the Environmental Benefits Mapping and Analysis Program 

version 4.065 (BenMAP).559 BenMAP is a computer program developed by the 

U.S. EPA that integrates a number of the modeling elements used in previous 

analyses (e.g., interpolation functions, population projections, health impact 

functions, valuation functions, analysis and pooling methods) to translate modeled 

air concentration estimates into health effects incidence estimates and monetized 

benefits estimates.

The range of total monetized ozone- and PM-related health impacts 

projected in 2030 is presented in Table VIII-1. We present total benefits based on 

the PM- and ozone-related premature mortality function used. The benefits ranges 

therefore reflect the addition of each estimate of ozone-related premature mortality

(each with its own row in Table VIII-1) to estimates of PM-related premature 

mortality. 

Table VIII-1 Estimated 2030 Monetized PM-and Ozone-Related Health 

Benefits

2030 Total Ozone and PM Benefits – PM Mortality Derived from American Cancer Society Analysis and 

Six-Cities Analysisa

Premature Ozone 

Mortality Function

Reference Total Benefits

(Billions, 2011$, 3% 

Total Benefits

(Billions, 2011$, 7% 

 

557 U.S. Environmental Protection Agency. (2012). Regulatory Impact Analysis for the Final 

Revisions to the National Ambient Air Quality Standards for Particulate Matter. Prepared by: 

Office of Air and Radiation, EPA-452/R-12-005. Retrieved August 14, 2013 at 

http://www.epa.gov/ttn/ecas/ria.html

558 U.S. Environmental Protection Agency. (2008). Final Ozone NAAQS Regulatory Impact 

Analysis. Prepared by: Office of Air and Radiation, Office of Air Quality Planning and Standards. 

Retrieved August 14, 2013 at http://www.epa.gov/ttn/ecas/ria.html

559 Information on BenMAP, including downloads of the software, can be found at 

http://www.epa.gov/ttn/ecas/ benmodels.html.
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Discount Rate)b,c Discount Rate) b,c

Multi-city analyses Bell et al., 2004 Total: $7.4 - $15

PM: $6.0 - $14

Ozone: $1.1

Total: $6.7 - $14

PM: $5.4 - $12

Ozone: $1.1

Huang et al., 2005 Total: $7.9 - $16

PM: $6.0 - $14

Ozone: $1.7

Total: $7.3 - $14

PM: $5.4 - $12

Ozone: $1.7

Schwartz, 2005 Total: $8.0 - $16

PM: $6.0 - $14

Ozone: $1.7

Total: $7.3 - $14

PM: $5.4 - $12

Ozone: $1.7

Meta-analyses Bell et al., 2005 Total: $9.8 - $18

PM: $6.0 - $14

Ozone: $3.6

Total: $9.2 - $16

PM: $5.4 - $12

Ozone: $3.6

Ito et al., 2005 Total: $11 - $19

PM: $6.0 - $14

Ozone: $4.9

Total: $11 - $18

PM: $5.4 - $12

Ozone: $4.9

Levy et al., 2005 Total: $11 - $19

PM: $6.0 - $14

Ozone: $5.0

Total: $11 - $18

PM: $5.4 - $12

Ozone: $5.0

.

a Total includes premature mortality-related and morbidity-related ozone and PM2.5 estimated 

benefits. Range was developed by adding the estimate from the ozone premature mortality function 

to the estimate of PM2.5-related premature mortality derived from either the ACS study (Krewski et 

al., 2009) or the Six-Cities study (Lepeule et al., 2012). Range also reflects alternative estimates of 

non-fatal heart attacks avoided based on either Peters et al. (2001) or a pooled estimate of four 

studies.

b Note that total benefits presented here do not include a number of unquantified benefits categories. 

A detailed listing of unquantified health and welfare effects is provided in Table VIII-2.

c Results reflect the use of both a 3 and 7 percent discount rate, as recommended by EPA’s 

Guidelines for Preparing Economic Analyses and OMB Circular A-4. Results are rounded to two 

significant digits for ease of presentation and computation. Totals may not sum due to rounding.

The benefits analysis presented in this chapter incorporates an array of 

policy and technical changes that the Agency has adopted since the Tier 3 

proposal’s draft RIA. These changes reflect EPA’s work to update PM-related

benefits reflected in the most recent PM NAAQS.560 Below we note the aspects of 

this analysis that differ from the Tier 3 proposal’s draft RIA:561

1. Incorporation of the newest American Cancer Society (ACS) mortality

study and newest Harvard Six Cities mortality study. In 2012, Lepeule et al. 

 

560 U.S. Environmental Protection Agency. (2012). Regulatory Impact Analysis for the Final 

Revisions to the National Ambient Air Quality Standards for Particulate Matter. Prepared by: Office 

of Air and Radiation, EPA-452/R-12-005. Retrieved August 14, 2013 at 

http://www.epa.gov/ttn/ecas/ria.html

561 U.S. Environmental Protection Agency. (2013). Draft Regulatory Impact Analysis: Tier 3 Motor 

Vehicle Emission and Fuel Standards. Prepared by: Office of Air and Radiation. EPA-420-D-13-

002. Retrieved October 18, 2013 at http://www.epa.gov/otaq/documents/tier3/420d13002.pdf
Page 475 of 529

published an extended analysis of the Six Cities cohort.562 Compared to the 

study it replaces (Laden et al., 2006),

563 this new analysis follows the cohort 

for a longer time and includes more years of PM2.5 monitoring data. The allcause PM2.5 mortality risk coefficient drawn from Lepeule et al. is roughly 

similar to the Laden et al. risk coefficient applied in the EPA’s recent analyses 

of long-term PM2.5 mortality and has narrower confidence intervals. 

In 2009, the Health Effects Institute published an extended analysis of the 

ACS cohort (Krewski et al., 2009).564 Compared to the study it replaces (Pope 

et al., 2002),565 this new analysis incorporates a number of methodological 

improvements.

566 The all-cause PM2.5 mortality risk estimate drawn from 

Krewski et al. (2009) is identical to the Pope et al. (2002) risk estimate applied 

in recent EPA analyses of long-term PM2.5 mortality but has narrower 

confidence intervals.

2. Updated health endpoints. We have removed the quantification of chronic 

bronchitis from our main analysis. This change is consistent with the findings 

of the PM Integrated Science Assessment (ISA) that the evidence for an 

association between long-term exposure to PM2.5 and respiratory effects is 

more tenuous.

567

3. Updated demographic data. We updated the population demographic data 

in BenMAP to reflect the 2010 Census and future projections based on 

economic forecasting models developed by Woods and Poole, Inc.568 These 

data replace the earlier demographic projection data from Woods and Poole 

(2011).569

 

562 Lepeule J, Laden F, Dockery D, Schwartz J. 2012. Chronic Exposure to Fine Particles and 

Mortality: An Extended Follow-Up of the Harvard Six Cities Study from 1974 to 2009. Environ 

Health Perspect. Jul;120(7):965-70.

563 Laden, F., J. Schwartz, F.E. Speizer, and D.W. Dockery. 2006. “Reduction in Fine Particulate Air 

Pollution and Mortality.” American Journal of Respiratory and Critical Care Medicine 173:667-672.

564 Krewski, D., M. Jerret, R.T. Burnett, R. Ma, E. Hughes, Y. Shi, et al. (2009). Extended followup and spatial analysis of the American Cancer Society study linking particulate air pollution and 

mortality. HEI Research Report, 140,Health Effects Institute, Boston, MA.

565 Pope, C.A., III, R.T. Burnett, M.J. Thun, E.E. Calle, D. Krewski, K. Ito, and G.D. Thurston. 

2002. “Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air 

Pollution.” Journal of the American Medical Association 287:1132-1141.

566 Refer to the 2012 PM NAAQS RIA for more detail regarding the studies themselves.

567 U.S. Environmental Protection Agency (U.S. EPA). 2009. Integrated Science Assessment for 

Particulate Matter (Final Report). EPA-600-R-08-139F. National Center for Environmental 

Assessment—RTP Division. December. Available on the Internet at 

<http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546>.

568 Woods & Poole Economics Inc. 2012. Population by Single Year of Age. CD-ROM. Woods & 

Poole Economics, Inc. Washington, D.C.

569 Woods & Poole Economics, Inc. (2011). 2012 Complete Economic and Demographic Data 

Source (CEDDS).
Page 476 of 529

4. Incorporation of new morbidity studies. Since the publication of the 2004 

Criteria Document for Particulate Matter,

570 the publication of the more recent 

PM ISA,571 and the Provisional Assessment of Recent Studies on Health 

Effects of Particulate Matter Exposure (“Provisional Assessment”),572 the 

epidemiological literature has produced several new studies examining the 

association between short-term PM2.5 exposure and acute myocardial 

infarctions, respiratory and cardiovascular hospitalizations, respiratory and 

cardiovascular emergency department visits, acute respiratory symptoms and 

exacerbation of asthma, respiratory and cardiovascular hospitalizations. Upon 

careful evaluation of this new literature, we added several new studies to our 

health impact assessment; in many cases we have replaced older single-city 

time-series studies with newer multi-city time-series analyses.

5. Updated the survival rates for non-fatal acute myocardial infarctions.

Based on recent data from Agency for Healthcare Research and Quality’s 

Healthcare Utilization Project National Inpatient Sample database,573 we 

identified death rates for adults hospitalized with acute myocardial infarction 

stratified by age. These rates replace the survival rates from Rosamond et al. 

(1999).574

6. Updated hospital cost-of-illness (COI), including median wage data. In 

previous benefits analyses, estimates of hospital charges and lengths of 

hospital stays were based on discharge statistics provided by the Agency for 

Healthcare Research and Quality’s Healthcare Utilization Project National 

Inpatient Sample (NIS) database for 2000.575 The version of BenMAP 

(version 4.0.65) used in this analysis updated this information to use the 2007 

 

570 U.S. Environmental Protection Agency (U.S. EPA). 2004. Air Quality Criteria for Particulate 

Matter. National Center for Environmental Assessment, Office of Research and Development, U.S. 

Environmental Protection Agency, Research Triangle Park, NC EPA/600/P-99/002bF. Available on 

the Internet at <http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=87903>.

571 U.S. Environmental Protection Agency (U.S. EPA). 2009. Integrated Science Assessment for 

Particulate Matter (Final Report). EPA-600-R-08-139F. National Center for Environmental 

Assessment—RTP Division. December. Available on the Internet at 

<http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546>.

572 U.S. Environmental Protection Agency (U.S. EPA). 2012. Provisional Assessment of Recent 

Studies on Health Effects of Particulate Matter Exposure. EPA/600/R-12/056A. National Center for 

Environmental Assessment—RTP Division. December.

573 Agency for Healthcare Research and Quality (AHRQ). 2009. HCUPnet, Healthcare Cost and 

Utilization Project. Rockville, MD. Available on the Internet at <http://hcupnet.ahrq.gov>.American 

Lung Association (ALA). 1999. Chronic Bronchitis. Available on the Internet at 

<http://www.lungusa.org/diseases/lungchronic.html>.

574 Rosamond, W., G. Broda, E. Kawalec, S. Rywik, A. Pajak, L. Cooper, and L. Chambless. 1999. 

“Comparison of Medical Care and Survival of Hospitalized Patients with Acute Myocardial 

Infarction in Poland and the United States.” American Journal of Cardiology 83:1180-1185.

575 Agency for Healthcare Research and Quality (AHRQ). 2000. HCUPnet, Healthcare Cost and 

Utilization Project. Rockville, MD. Available on the Internet at <http://hcupnet.ahrq.gov>.
Page 477 of 529

database. The data source for the updated median annual income is the 2007 

American Community Survey.

The benefits in Table VIII-1 include all of the estimated human health 

impacts we are able to quantify and monetize at this time. However, the full 

complement of human health effects associated with PM, ozone and other criteria 

pollutants remain unquantified because of current limitations in methods and/or 

available data. We have not quantified a number of known or suspected health 

effects linked with these pollutants for which appropriate health impact functions 

are not available or which do not provide easily interpretable outcomes (e.g., 

changes in heart rate variability). These are listed in Table VIII-2. As a result of 

these omissions, the health benefits quantified in this section are likely 

underestimates of the total benefits attributable to the final standards.

Table VIII-2 Estimated Quantified and Unquantified Health Effects

BENEFITS 

CATEGORY

SPECIFIC EFFECT EFFECT HAS 

BEEN 

QUANTIFIED

EFFECT HAS 

BEEN 

MONETIZED

MORE 

INFORMATION

Improved Human Health

Reduced 

incidence of 

premature 

mortality and 

morbidity from 

exposure to PM2.5

Adult premature mortality based on 

cohort study estimates and expert 

elicitation estimates (age >25 or age 

>30)

  PM NAAQS RIA, 

Section 5.6

Infant mortality (age <1)   PM NAAQS RIA, 

Section 5.6

Non-fatal heart attacks (age > 18)   PM NAAQS RIA, 

Section 5.6

Hospital admissions—respiratory (all 

ages)

  PM NAAQS RIA, 

Section 5.6

Hospital admissions—cardiovascular 

(age >20)

  PM NAAQS RIA, 

Section 5.6

Emergency department visits for 

asthma (all ages)

  PM NAAQS RIA, 

Section 5.6

Acute bronchitis (age 8–12)   PM NAAQS RIA, 

Section 5.6

Lower respiratory symptoms (age 7–

14)

  PM NAAQS RIA, 

Section 5.6

Upper respiratory symptoms 

(asthmatics age 9–11)

  PM NAAQS RIA, 

Section 5.6

Asthma exacerbation (asthmatics age   PM NAAQS RIA, 
Page 478 of 529

BENEFITS 

CATEGORY

SPECIFIC EFFECT EFFECT HAS 

BEEN 

QUANTIFIED

EFFECT HAS 

BEEN 

MONETIZED

MORE 

INFORMATION

6–18) Section 5.6

Lost work days (age 18–65)   PM NAAQS RIA, 

Section 5.6

Minor restricted-activity days (age 

18–65)

  PM NAAQS RIA, 

Section 5.6

Chronic Bronchitis (age >26) — — PM NAAQS RIA, 

Section 5.6c

Emergency department visits for 

cardiovascular effects (all ages)

— — PM NAAQS RIA, 

Section 5.6c

Strokes and cerebrovascular disease 

(age 50–79)

— — PM NAAQS RIA, 

Section 5.6c

Other cardiovascular effects (e.g., 

other ages)

— — PM ISAa

Other respiratory effects (e.g., 

pulmonary function, non-asthma ER 

visits, non-bronchitis chronic 

diseases, other ages and populations)

— — PM ISAa

Reproductive and developmental 

effects (e.g., low birth weight, preterm births, etc.)

— — PM ISAa,b

Cancer, mutagenicity, and 

genotoxicity effects

— — PM ISAa,b

Reduced 

incidence of 

premature 

mortality and 

morbidity from 

exposure to 

ozone

Premature mortality based on shortterm study estimates (all ages)  Ozone ISA

Premature mortality based on longterm study estimates (age 30–99)— — Ozone ISAc

Hospital admissions—respiratory

causes (age > 65)

  Ozone ISA

Hospital admissions—respiratory 

causes (age <2)

  Ozone ISA

Emergency department visits for 

asthma (all ages)

  Ozone ISA

Minor restricted-activity days (age 

18–65)

  Ozone ISA

School absence days (age 5–17)   Ozone ISA

Decreased outdoor worker   Ozone ISA
Page 479 of 529

BENEFITS 

CATEGORY

SPECIFIC EFFECT EFFECT HAS 

BEEN 

QUANTIFIED

EFFECT HAS 

BEEN 

MONETIZED

MORE 

INFORMATION

productivity (age 18–65)

Other respiratory effects (e.g., 

premature aging of lungs)

— — Ozone ISAa

Cardiovascular and nervous system 

effects

— — Ozone ISAb

Reproductive and developmental 

effects

— — Ozone ISAb

Reduced 

incidence of 

morbidity from 

exposure to air 

toxics

Cancer (benzene, 1,3-butadiene, 

formaldehyde, acetaldehyde)

Anemia (benzene)

Disruption of production of blood 

components (benzene)

Reduction in the number of blood 

platelets (benzene)

Excessive bone marrow formation 

(benzene)

Depression of lymphocyte counts 

(benzene)

Reproductive and developmental 

effects (1,3-butadiene)

Irritation of eyes and mucus 

membranes (formaldehyde)

Respiratory irritation (formaldehyde)

Asthma attacks in asthmatics 

(formaldehyde)

Asthma-like symptoms in nonasthmatics (formaldehyde)

Irritation of the eyes, skin, and 

respiratory tract (acetaldehyde)

Upper respiratory tract irritation and 

congestion (acrolein)

— — IRISa,b

a We assess these benefits qualitatively because we do not have sufficient confidence in available 

data or methods.

b We assess these benefits qualitatively because current evidence is only suggestive of causality or 

there are other significant concerns over the strength of the association.

c We assess these benefits qualitatively due to time and resource limitations for this analysis.

While there would be impacts associated with reductions in air toxic 

pollutant emissions that result from the final standards, we do not attempt to

quantify and monetize those impacts (Section III presents the estimated emission 

reductions associated with the final standards). This is primarily because currently 

available tools and methods to assess air toxics risk from mobile sources at the 
Page 480 of 529

national scale are not adequate for extrapolation to incidence estimations or benefits 

assessment. The best suite of tools and methods currently available for assessment 

at the national scale are those used in the National-Scale Air Toxics Assessment 

(NATA). The EPA Science Advisory Board specifically commented in their 

review of the 1996 NATA that these tools were not yet ready for use in a nationalscale benefits analysis, because they did not consider the full distribution of 

exposure and risk, or address sub-chronic health effects.576 While EPA has since 

improved these tools, there remain critical limitations for estimating incidence and 

assessing benefits of reducing mobile source air toxics. 

As part of the second prospective analysis of the benefits and costs of the 

Clean Air Act,577 EPA conducted a case study analysis of the estimated health 

effects associated with reducing exposure to benzene in Houston from 

implementation of the Clean Air Act. While reviewing the draft report, EPA’s 

Advisory Council on Clean Air Compliance Analysis concluded that “the 

challenges for assessing progress in health improvement as a result of reductions in 

emissions of hazardous air pollutants (HAPs) are daunting...due to a lack of 

exposure-response functions, uncertainties in emissions inventories and background 

levels, the difficulty of extrapolating risk estimates to low doses and the challenges 

of tracking health progress for diseases, such as cancer, that have long latency 

periods.”578 EPA continues to work to address these limitations; however, we did 

not have the methods and tools available for national-scale application in time for 

the analysis of the final standards.579 

The reduction in air pollution emissions that will result from the final 

program also is projected to have “welfare” co-benefits in addition to human health 

benefits, including changes in visibility, materials damage, ecological effects from 

PM deposition, ecological effects from nitrogen and sulfur emissions, vegetation 

 

576 Science Advisory Board. (2001). NATA – Evaluating the National-Scale Air Toxics Assessment 

for 1996 – an SAB Advisory. http://www.epa.gov/ttn/atw/sab/sabrev.html.

577 U.S. Environmental Protection Agency (U.S. EPA). (2011). The Benefits and Costs of the Clean 

Air Act from 1990 to 2020. Office of Air and Radiation, Washington, DC. March. Available on the 

Internet at <http://www.epa.gov/air/sect812/feb11/fullreport.pdf>.

578 U.S. Environmental Protection Agency—Science Advisory Board (U.S. EPA-SAB). (2008). 

Benefits of Reducing Benzene Emissions in Houston, 1990–2020. EPA-COUNCIL-08-001. July. 

Available at 

<http://yosemite.epa.gov/sab/sabproduct.nsf/D4D7EC9DAEDA8A548525748600728A83/$File/EP

A-COUNCIL-08-001-unsigned.pdf>.

579 In April, 2009, EPA hosted a workshop on estimating the benefits or reducing hazardous air 

pollutants. This workshop built upon the work accomplished in the June 2000 Science Advisory 

Board/EPA Workshop on the Benefits of Reductions in Exposure to Hazardous Air Pollutants, 

which generated thoughtful discussion on approaches to estimating human health benefits from 

reductions in air toxics exposure, but no consensus was reached on methods that could be 

implemented in the near term for a broad selection of air toxics. Please visit 

http://epa.gov/air/toxicair/2009workshop.html for more information about the workshop and its 

associated materials.
Page 481 of 529

effects from ozone exposure, and climate effects.580 Despite our goal to quantify

and monetize as many of the benefits as possible for the final rulemaking, the 

welfare co-benefits of the Tier 3 standards remain unquantified and non-monetized 

due to data, methodology, and resource limitations. As a result, the benefits 

quantified in this analysis are likely underestimates of the total benefits attributable 

to the final program. We refer the reader to Chapter 6 of the PM NAAQS RIA for a 

complete discussion of these welfare co-benefits.581

We received many comments from the public and interested stakeholders, 

many of which were supportive of the benefits analysis conducted in support of the 

rulemaking and some that were adverse. Several commenters (primarily associated 

with the fuels industry) were critical of a number of EPA assumptions and other 

aspects of the analysis.

As described more fully in the Summary and Analysis of Comments 

document that accompanies this rulemaking, EPA disagrees with the claims of these 

commenters. We base our analysis of the program’s impact on human health and 

the environment on peer-reviewed studies of air quality and human health 

effects.582,583 Our benefits methods are consistent with the RIA that accompanied 

the final revisions to the National Ambient Air Quality Standards (NAAQS) for 

Particulate Matter and the final ozone NAAQS. Our methods also undergo rigorous 

review by many independent expert panels, including the Science Advisory Board 

and the National Research Council. Our methods and assumptions reflect their 

guidance, review, and recommendations. As a result, we believe our analysis 

reflects the state of the science for health impacts and benefits assessment. 

The Agency also received many comments supportive of the benefits that 

the Tier 3 standards will achieve. This includes broad support from many nongovernmental institutions, state and local governments, and private citizens. 

 

580 We project that the Tier 3 vehicle and fuel standards will reduce nitrous oxide (N2O) and methane 

(CH4) emissions from vehicles. The reductions in these potent greenhouse gases will be offset to 

some degree by the increase in CO2 emissions from refineries. The combined impact is a net 

decrease on a CO2-equivalent basis and would yield a net benefit if these reductions were 

monetized.

581 U.S. Environmental Protection Agency. (2012). Regulatory Impact Analysis for the Final 

Revisions to the National Ambient Air Quality Standards for Particulate Matter. Prepared by: 

Office of Air and Radiation, EPA-452/R-12-005. Retrieved August 14, 2013 at 

http://www.epa.gov/ttn/ecas/ria.html

582 U.S. Environmental Protection Agency. (2012). Regulatory Impact Analysis for the Final 

Revisions to the National Ambient Air Quality Standards for Particulate Matter. Prepared by: 

Office of Air and Radiation, EPA-452/R-12-005. Retrieved August 14, 2013 at 

http://www.epa.gov/ttn/ecas/ria.html

583 U.S. Environmental Protection Agency. (2008). Final Ozone NAAQS Regulatory Impact 

Analysis. Prepared by: Office of Air and Radiation, Office of Air Quality Planning and Standards. 

Retrieved March, 26, 2009 at http://www.epa.gov/ttn/ecas/ria.html. EPA-HQ-OAR-2009-0472-0238
Page 482 of 529

B. Quantified Human Health Impacts

Table VIII-3 and Table VIII-4 present the core estimates of annual PM2.5

and ozone health impacts, respectively, in the 48 contiguous U.S. states associated 

with the final standards for 2030. For each endpoint presented in Table VIII-3 and 

Table VIII-4, we provide both the mean estimate and the 90 percent confidence 

interval. 

Using EPA’s preferred estimates, based on the American Cancer Society 

(ACS) and Six-Cities studies and no threshold assumption in the model of 

mortality, we estimate that the final standards would result in between 660 and 

1,500 cases of avoided PM2.5-related premature mortalities annually in 2030. A 

sensitivity analysis was also conducted to understand the impact of alternative 

concentration response functions suggested by experts in the field. When the range 

of expert opinion is used, we estimate between 130 and 2,200 fewer premature 

mortalities in 2030 (see Table 8.8 in the RIA that accompanies this action). For 

ozone-related premature mortality in 2030, we estimate a range of between 110 to 

500 fewer premature mortalities. 

Table VIII-3 Estimated PM2.5-Related Health Impactsa

Health Effect 2030 Annual 

Reduction in 

Incidence

(5th% - 95th%ile)

Premature Mortality – Derived from epidemiology literatureb

 Adult, age 30+, ACS Cohort Study (Krewski et al., 2009)

 Adult, age 25+, Six-Cities Study (Lepeule et al., 2012)

 Infant, age <1 year (Woodruff et al., 1997)

660

(480 – 840)

1,500

(860 – 2,100)

Non-fatal myocardial infarction (adult, age 18 and over)

 Peters et al. (2001)

 Pooled estimate of 4 studies

790

(290 – 1,300)

85

(42 – 190)

Hospital admissions - respiratory (all ages)c,e 210

(-38 – 380)

Hospital admissions - cardiovascular (adults, age >18)d250

(130 – 440)

Emergency room visits for asthma (age 18 years and younger)e340

(-58 – 660)

Acute bronchitis, (children, age 8-12)e980

(-35 – 2,000)

Lower respiratory symptoms (children, age 7-14) 13,000

(6,000 – 19,000)

Upper respiratory symptoms (asthmatic children, age 9-18) 18,000

(5,600 – 30,000)

Asthma exacerbation (asthmatic children, age 6-18) 19,000

(2,300 – 37,000)

Work loss days 81,000

(70,000 – 91,000)
Page 483 of 529

Minor restricted activity days (adults age 18-65) 480,000

(400,000 – 550,000)

a

Incidence is rounded to two significant digits. Estimates represent incidence within the 48 

contiguous United States. 

b

PM-related adult mortality based upon the most recent American Cancer Society (ACS) Cohort 

Study (Krewski et al., 2009) and the most recent Six-Cities Study (Lepeule et al., 2012). Note 

that these are two alternative estimates of adult mortality and should not be summed. PMrelated infant mortality based upon a study by Woodruff, Grillo, and Schoendorf, (1997).584

c Respiratory hospital admissions for PM include admissions for chronic obstructive pulmonary 

disease (COPD), pneumonia and asthma.

d Cardiovascular hospital admissions for PM include total cardiovascular and subcategories for 

ischemic heart disease, dysrhythmias, and heart failure.

e The negative estimates at the 5th percentile confidence estimates for these morbidity endpoints 

reflect the statistical power of the study used to calculate these health impacts. These results do 

not suggest that reducing air pollution results in additional health impacts.

Table VIII-4 Estimated Ozone-Related Health Impactsa

Health Effect 2030 Annual Reduction 

in Incidence

(5th% - 95th%ile)

Premature Mortality, All agesb

Multi-City Analyses 

 Bell et al. (2004) – Non-accidental

 Huang et al. (2005) – Cardiopulmonary

 Schwartz (2005) – Non-accidental

Meta-analyses:

 Bell et al. (2005) – All cause

 Ito et al. (2005) – Non-accidental

 Levy et al. (2005) – All cause

110

(46 – 170)

160

(74 – 250)

170

(68 – 270)

350

(190 – 510)

490

(320 – 660)

500

(360 – 630)

Hospital admissions- respiratory causes (adult, 65 and 

older)c

740

(87 – 1,400)

Hospital admissions -respiratory causes (children, under 2) 310

(160 – 450)

Emergency room visit for asthma (all ages)d330

(-8 – 990)

Minor restricted activity days (adults, age 18-65) 600,000

(290,000 – 910,000)

School absence days 210,000

(92,000 – 300,000)

 

584 Woodruff, T.J., J. Grillo, and K.C. Schoendorf. (1997). The Relationship Between Selected 

Causes of Postneonatal Infant Mortality and Particulate Air Pollution in the United States. 

Environmental Health Perspectives 105(6):608-612.
Page 484 of 529

a

Incidence is rounded to two significant digits. Estimates represent incidence within the 48 

contiguous U.S. 

b Estimates of ozone-related premature mortality are based upon incidence estimates derived 

from several alternative studies: Bell et al. (2004); Huang et al. (2005); Schwartz (2005) ; Bell 

et al. (2005); Ito et al. (2005); Levy et al. (2005). The estimates of ozone-related premature 

mortality should therefore not be summed.

c Respiratory hospital admissions for ozone include admissions for all respiratory causes and 

subcategories for COPD and pneumonia. 

d The negative estimate at the 5th percentile confidence estimate for this morbidity endpoint

reflects the statistical power of the study used to calculate this health impact. This result does

not suggest that reducing air pollution results in additional health impacts.

C. Monetized Benefits

Table VIII-5 presents the estimated monetary value of changes in the 

incidence of ozone and PM2.5-related health effects. All monetized estimates are 

stated in 2011 dollars. These estimates account for growth in real gross domestic 

product (GDP) per capita between the present and 2030. Our estimate of total 

monetized benefits in 2030 for the program, using the ACS and Six-Cities PM 

mortality studies and the range of ozone mortality assumptions, is between $7.4 and 

$19 billion, assuming a 3 percent discount rate, or between $6.7 and $18 billion, 

assuming a 7 percent discount rate. This represents the health benefits of the Tier 3 

program anticipated to occur annually when the program is fully implemented and 

most of the fleet turned over.

Table VIII-5 Estimated Monetary Value of Changes in Incidence of Health 

and Welfare Effects in 2030 (Millions of 2011$) a

HEALTH ENDPOINTS 2030

(5TH AND 95TH

PERCENTILE)

PM2.5-Related Health Effects

Premature Mortality – Derived 

from Epidemiology Studiesb,c

Adult, age 30+ - ACS study 

(Krewski et al., 2009)

 3% discount rate

 7% discount rate

$6,100

($910 - $14,000)

$5,500

($820 - $13,000)

Adult, age 25+ - Six-Cities study 

(Lepeule et al., 2012)

 3% discount rate

 7% discount rate

$14,000

($2,000 - $33,000)

$12,000

($1,800 - $30,000)

Infant Mortality, <1 year –

(Woodruff et al. 1997)

$13

($1.8 - $32)

Non-fatal acute myocardial infarctions 

 Peters et al., 2001

 3% discount rate

 7% discount rate

 Pooled estimate of 4 studies

$96

($21 - $230)

$93

($19 - $220)
Page 485 of 529

 3% discount rate

 7% discount rate

$10

($2.6 - $27)

$10

($2.4 - $27)

Hospital admissions for respiratory causesd$5.9

(-$1.6 - $11)

Hospital admissions for cardiovascular causes $9.9

($5.0 - $17)

Emergency room visits for asthmad$0.15

(-$0.02 - $0.29)

Acute bronchitis (children, age 8–12)d$0.49

(-$0.02 - $1.2)

Lower respiratory symptoms (children, 7–14) $0.27

($0.11 - $0.51)

Upper respiratory symptoms (asthma, 9–11) $0.62

($0.18 - $1.4)

Asthma exacerbations $1.1

($0.14 - $2.7)

Work loss days $12

($11 – $14)

Minor restricted-activity days (MRADs) $34

($20 - $49)

Ozone-Related Health Effects

Premature Mortality, All ages –

Derived from Multi-city analyses

Bell et al., 2004 $1,100

($150 - $2,800)

Huang et al., 2005 $1,600

($220 - $4,100)

Schwartz, 2005 $1,700

($220 - $4,400)

Premature Mortality, All ages –

Derived from Meta-analyses

Bell et al., 2005 $3,600

($510 - $8,800)

Ito et al., 2005 $5,000

($740 - $12,000

Levy et al., 2005 $5,100

($760 - $12,000)

Hospital admissions- respiratory causes (adult, 65 and older) $21

($2.5 - $39)

Hospital admissions- respiratory causes (children, under 2) $3.7

($1.9 - $5.4)

Emergency room visit for asthma (all ages) $0.14

(-$0.003 - $0.41)

Minor restricted activity days (adults, age 18-65) $43

($19 - $73)

School absence days $21

($9.3 - $31)

a Monetary benefits are rounded to two significant digits for ease of presentation and computation. 

PM and ozone benefits are nationwide. 

b Monetary benefits adjusted to account for growth in real GDP per capita between 1990 and the 

analysis year (2030).

c Valuation assumes discounting over the SAB recommended 20 year segmented lag structure. 

Results reflect the use of 3 percent and 7 percent discount rates consistent with EPA and OMB 

guidelines for preparing economic analyses.
Page 486 of 529

d The negative estimate at the 5th percentile confidence estimate for this morbidity endpoint reflects

the statistical power of the study used to calculate this health impact. This result does not suggest 

that reducing air pollution results in additional health impacts.

D. What are the Limitations of the Benefits Analysis?

Every benefit-cost analysis examining the potential effects of a change in 

environmental protection requirements is limited to some extent by data gaps, 

limitations in model capabilities (such as geographic coverage), and uncertainties in 

the underlying scientific and economic studies used to configure the benefit and 

cost models. Limitations of the scientific literature often result in the inability to 

estimate quantitative changes in health and environmental effects, such as potential 

decreases in premature mortality associated with decreased exposure to carbon 

monoxide. Deficiencies in the economics literature often result in the inability to 

assign economic values even to those health and environmental outcomes which 

can be quantified. These general uncertainties in the underlying scientific and 

economics literature, which can lead to valuations that are higher or lower, are 

discussed in detail in the RIA and its supporting references. Key uncertainties that 

have a bearing on the results of the benefit-cost analysis of the final standards 

include the following:

 The exclusion of potentially significant and unquantified benefit 

categories (such as health, odor, and ecological benefits of reduction in 

air toxics, ozone, and PM);

 Errors in measurement and projection for variables such as population 

growth;

 Uncertainties in the estimation of future year emissions inventories and

air quality (including future year climate uncertainty);

 Uncertainty in the estimated relationships of health and welfare effects 

to changes in pollutant concentrations including the shape of the 

concentration-response function, the size of the effect estimates, and the 

relative toxicity of the many components of the PM mixture; 

 Uncertainties in exposure estimation; and

 Uncertainties associated with the effect of potential future actions to 

limit emissions.

As Table VIII-5 indicates, total benefit estimates are driven primarily by the 

reduction in premature mortalities each year. Some key assumptions underlying the 

premature mortality estimates include the following, which may also contribute to 

uncertainty:
Page 487 of 529

 We assume that all fine particles, regardless of their chemical 

composition, are equally potent in causing premature mortality. This is 

an important assumption, because PM2.5 varies considerably in 

composition across sources, but the scientific evidence is not yet 

sufficient to allow differential effects estimates by particle type. The 

2009 PM ISA, which was twice reviewed by EPA’s Science Advisory

Board Clean Air Science Advisory Committee (SAB-CASAC), 

concluded that “many constituents of PM2.5 can be linked with multiple 

health effects, and the evidence is not yet sufficient to allow 

differentiation of those constituents or sources that are more closely 

related to specific outcomes.”

585

 We assume that the health impact function for fine particles is log-linear 

without a threshold in this analysis. Thus, the estimates include health 

benefits from reducing fine particles in areas with varied concentrations 

of PM2.5, including both areas that do not meet the fine particle standard 

and those areas that are in attainment, down to the lowest modeled 

concentrations.

 We assume that there is a “cessation” lag between the change in PM 

exposures and the total realization of changes in mortality effects. 

Specifically, we assume that some of the incidences of premature 

mortality related to PM2.5 exposures occur in a distributed fashion over 

the 20 years following exposure based on the advice of EPA’s Science 

Advisory Board Health Effects Subcommittee (SAB-HES),

586 which 

affects the valuation of mortality benefits at different discount rates.

 There is uncertainty in the magnitude of the association between ozone 

and premature mortality. The range of ozone benefits associated with 

the final standards is estimated based on the risk of several sources of 

ozone-related mortality effect estimates. In a report on the estimation of 

ozone-related premature mortality published by the National Research 

Council, a panel of experts and reviewers concluded that short-term 

exposure to ambient ozone is likely to contribute to premature deaths 

 

585 U.S. Environmental Protection Agency (U.S. EPA). 2009. Integrated Science Assessment for 

Particulate Matter (Final Report). EPA-600-R-08-139F. National Center for Environmental 

Assessment—RTP Division. December. Available on the Internet at 

<http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546>.

586 U.S. Environmental Protection Agency—Science Advisory Board (U.S. EPA-SAB). 2004. 

Advisory Council on Clean Air Compliance Analysis Response to Agency Request on Cessation 

Lag. EPA-COUNCIL-LTR-05-001. December. Available on the Internet at 

<http://yosemite.epa.gov/sab/sabproduct.nsf/0/39F44B098DB49F3C85257170005293E0/$File/coun

cil_ltr_05_001.pdf>.
Page 488 of 529

and that ozone-related mortality should be included in estimates of the 

health benefits of reducing ozone exposure.587 

Despite the uncertainties described above, we believe this analysis provides 

a conservative estimate of the estimated criteria pollutant-related health and 

environmental benefits of the standards in future years because of the exclusion of 

potentially significant benefit categories that are not quantifiable at this time. 

Acknowledging benefits omissions and uncertainties, we present a best estimate of 

the total benefits based on our interpretation of the best available scientific literature 

and methods supported by EPA’s technical peer review panel, the Science Advisory

Board’s Health Effects Subcommittee (SAB-HES). The National Academies of 

Science (NRC, 2002) has also reviewed EPA’s methodology for analyzing the 

health benefits of measures taken to reduce air pollution. EPA addressed many of 

these comments in the analysis of the final PM NAAQS.588,589 This analysis 

incorporates this work to the extent possible. 

E. Illustrative Analysis of Estimated Monetized Impacts Associated with the 

Rule in 2018

For illustrative purposes, this section presents the total estimated monetized 

benefits associated with the final standards in 2018. As presented in Section III.B, 

the emissions impacts of the final standards in 2018 are primarily due to the effects 

of sulfur on the existing (pre-Tier 3) fleet. 

Table VIII-6 presents total aggregate monetized benefits of the program in 

2018. Monetized estimates are presented in 2011$. Our estimate of total monetized 

benefits associated with the final standards in 2018, using the ACS and Six-Cities 

PM mortality studies and the range of ozone mortality assumptions, is between $2.1 

and $5.6 billion, assuming a 3 percent discount rate, or between $1.9 and $5.3 

billion, assuming a 7 percent discount rate. For a more detailed presentation of the 

quantified and monetized impacts of the final standards in 2018, please refer to 

Chapter 8 of the RIA that accompanies this preamble.

 

587 National Research Council (NRC), (2008). Estimating Mortality Risk Reduction and Economic 

Benefits from Controlling Ozone Air Pollution. The National Academies Press: Washington, D.C.

588 National Research Council (NRC). (2002). Estimating the Public Health Benefits of Proposed Air 

Pollution Regulations. The National Academies Press: Washington, D.C.

589 U.S. Environmental Protection Agency. (2012). Regulatory Impact Analysis for the Final 

Revisions to the National Ambient Air Quality Standards for Particulate Matter. Prepared by: 

Office of Air and Radiation, EPA-452/R-12-005. Retrieved August 14, 2013 at 

http://www.epa.gov/ttn/ecas/ria.html
Page 489 of 529

Table VIII-6 Total Estimated Monetized Ozone and PM-related Benefits 

Associated with the Final Standards in 2018

a

Total Ozone and PM Benefits (billions, 2011$) –

PM Mortality Derived from the ACS and Six-Cities Studies

3% Discount Rate 7% Discount Rate

Ozone 

Mortality 

Function

Reference Mean Total 

Benefits

Ozone 

Mortality 

Function

Reference Mean Total 

Benefits

Multi-city Bell et al., 

2004

$2.1 - $4.1 Multi-city Bell et al., 

2004

$1.9 - $3.7

Huang et al., 

2005

$2.3 - $4.2 Huang et al., 

2005

$2.1 - $3.9

Schwartz, 

2005

$2.3 - $4.3 Schwartz, 

2005

$2.1 - $3.9

Meta-analysis Bell et al., 

2005

$3.1 - $5.0 Meta-analysis Bell et al., 

2005

$2.9 - $4.7

Ito et al., 

2005

$3.6 - $5.6 Ito et al., 

2005

$3.4 - $5.2

Levy et al., 

2005

$3.6 - $5.6 Levy et al., 

2005

$3.5 - $5.3

Total Ozone and PM Benefits (billions, 2010$) –

PM Mortality Derived from Expert Elicitation (Lowest and Highest Estimate)

3% Discount Rate 7% Discount Rate

Ozone 

Mortality 

Function

Reference Mean Total 

Benefits

Ozone 

Mortality 

Function

Reference Mean Total 

Benefits

Multi-city Bell et al., 

2004

$0.81 - $5.8 Multi-city Bell et al., 

2004

$0.78 - $5.3

Huang et al., 

2005

$1.0 - $6.0 Huang et al., 

2005

$0.98 - $5.5

Schwartz, 

2005

$1.0 - $6.0 Schwartz, 

2005

$1.0 - $5.5

Meta-analysis Bell et al., 

2005

$1.8 - $6.8 Meta-analysis Bell et al., 

2005

$1.8 - $6.3

Ito et al., 

2005

$2.3 - $7.3 Ito et al., 

2005

$2.3 - $6.8

Levy et al., 

2005

$2.4 - $7.4 Levy et al., 

2005

$2.4 - $6.8

a Total includes estimated premature mortality-related and morbidity-related ozone and PM2.5

benefits. Range was developed by adding the estimate from the ozone premature mortality function 

to the estimate of PM2.5-related premature mortality derived from either the ACS study (Krewski et 

al., 2009) or the Six-Cities study (Lepeule et al., 2012) or the lowest and highest mortality estimate 

across the range derived from the expert elicitation. Range also reflects alternative estimates of nonfatal heart attacks avoided based on either Peters et al. (2001) or a pooled estimate of four studies.

IX. Alternatives Analysis

As described throughout this preamble, we have considered a number of 

regulatory alternatives in the development of this final rule, including alternatives 

related to timing and stringency of the standards, as well as alternative program 

design elements (e.g., averaging, banking, and trading). This section summarizes 

alternatives we have considered for both vehicle emission and fuel standards. 
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A. Vehicle Emission Standards

The federal vehicle emission standards we are adopting are the most 

stringent feasible considering anticipated developments in motor vehicle emissions 

control technology. Consideration of alternatives focused less on the level of the 

fleet-average and per-vehicle standards themselves and more on the phase-in 

schedule for the standards, which can have an important influence on the cost of the 

standards. Phase-in schedules directly impact costs depending on how they are 

aligned with other light-duty rules and product design cycles, especially those of the 

California LEV III criteria emissions program and the EPA greenhouse gas (GHG) 

rules. In addition, phase-in schedules can impact the cost of available resources, 

specifically design, development and testing resources within vehicle manufacturers 

and emission control suppliers.590 

As we considered options for the Tier 3 vehicle standards, one of the 

important factors we considered was the degree of harmonization that would result 

between Tier 3 and the CARB LEV III program. As discussed earlier in this 

preamble, the auto manufacturing industry stressed throughout the development of 

the Tier 3 rule and in their comments on the proposed rule – both as individual 

companies and through their trade associations – the need for harmonization of the 

two programs as completely and as soon as possible. 

Another factor in our consideration of program options has been how the 

timing of the Tier 3 program aligns with the federal light-duty vehicle GHG rules. 

We believe that both programs will be more efficient and less costly if 

manufacturers have greater ability to coordinate their product planning to respond 

to the various regulatory requirements they face.

For these reasons, we have focused on program alternatives that generally 

achieve close harmony with the California programs in the earliest appropriate time 

frame, and on a schedule matching those of the GHG rules as much as possible. 

The following paragraphs describe the major alternatives we have considered.

1. Shorter NMOG+NOX Standard Phase-in

We originally considered requiring full implementation of the NMOG+NOX

final fleet average standard by MY 2022. However, we determined that this would 

have disrupted the manufacturer’s normal product design cycles,591 and it would not 

have allowed manufacturers to use consistent product design cycles for both the 

Tier 3 standards and the 2017 LD GHG standards, which reach full implementation 

 

590 We note that the Tier 3 program includes additional phase-in flexibility through the alternative 

phase-in schedules for light-duty exhaust emissions standards, heavy-duty exhaust emissions 

standards, and light- and heavy-duty evaporative emissions standards. 

591 A light-duty vehicle product design cycle is the number of years between major redesigns of a 

vehicle. Typically, major redesigns are completed every 5 to 6 years.
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in MY 2025. We are adopting a phase-in schedule that gradually increases the 

stringency of the standards until MY 2025, as with the GHG program, in order to 

allow vehicle manufacturers to better integrate the compliance with Tier 3 into their 

product design cycles as well as to take advantage of additional learning to reduce 

costs. We believe this implementation schedule for the Tier 3 NMOG+NOX

standards allows us to achieve the environmental objectives of the program without 

imposing unnecessary costs and burden on the industry.

2. NMOG+NOX Standards Phase-in and Early Tier 3 Credits

The key agency goals in designing the structure of the Tier 3 program are to

facilitate the step-down in fleet average stringency in the initial model years and to 

create a program that is of equivalent stringency and aligned with LEV III as early 

as possible. We considered allowing manufacturers to generate early credits against 

the current Tier 2 Bin 5 fleet average and to use generated early credits without 

limitation for the first five years of the Tier 3 program. CARB, along with some 

vehicle manufacturers, noted that if a manufacturer were to substantially overcomply with the Tier 2 Bin 5 fleet average, these early credits might delay

achievement of the Tier 3 emission levels and also delay harmonization between the 

Tier 3 and LEV III programs for several years. Based on the fact that 

manufacturers are selling many vehicles today that are already cleaner than the 

existing Tier 2 Bin 5 fleet average, we believe that there is a strong potential for 

them to generate an excessive amount of credits. Also, most manufacturers will 

already have begun to sell vehicles that meet the LEV III standards (and thus the 

Tier 3 standards). The use of such a “windfall” of credits would likely result in a 

substantial delay in achieving alignment between the LEV III and Tier 3 programs. 

To avoid this potential misalignment, we are finalizing as proposed a 

provision that any early credits generated be capped starting in MY 2018 at the 

number of a manufacturer’s LEV III credits, but adjusted by the ratio of California 

and other LEV III sales nationwide. (See Section IV.A.7.a for more detail on these 

early credit provisions.) This approach balances the need for meaningful transition 

flexibility to avoid unnecessary costs, while still ensuring expeditious 

harmonization with LEV III and achievement of the environmental benefits of the 

Tier 3 standards.

3. NMOG+NOX Standards

We believe that the fleet-average NMOG+NOX standards that we are 

finalizing reflect the greatest degree of emission reduction achievable considering 

cost, developments in technology, and gasoline sulfur levels as required by this rule. 

We also believe the implementation schedule for the NMOG+ NOX standards is as 

short as practicable, as explained above. We believe that more stringent or less 

stringent standards are not justified based on the information currently available, 

including comments received. Therefore, and consistent with our goal of 

harmonizing the Tier 3 program with LEV III as much as possible, we are finalizing 
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the declining FTP and SFTP NMOG+NOX standards and phase-in schedules as 

proposed, as discussed in Section IV.A.3 and IV.A.4 above. 

4. PM Standards

The FTP and SFTP (US06) PM standards that we are adopting are the most 

stringent technically feasible standards within their implementation timeframe and 

meet the EPA goal of bringing all vehicles to the FTP and US06 PM emission 

levels demonstrated by most vehicles today. 

We considered adopting for Tier 3 the 1 mg/mi FTP PM standard that the 

LEV III program will begin phasing-in in MY 2025. However, as explained in the 

proposal and in Section IV.A.3.b above, and upon further review of current test 

procedures and the public comments, we concluded that 3 mg/mi is the most 

stringent technologically feasible FTP PM standard. We will continue to work 

closely with CARB in this area. Specifically, our agencies will continue our 

parallel evaluations of how improved gravimetric PM measurement methods can 

reduce PM mass measurement variability at very low PM levels, and how this 

relates to the evolving technological capabilities of automakers to reach very low 

PM levels with sufficient compliance margins. 

As discussed in Section IV.A.4, we are finalizing numerically lower US06 

standards than those we proposed. More recent test data shows that the levels of the 

final US06 standards better meet EPA’s goal of capping US06 PM emissions at 

levels already being demonstrated by most vehicles in the current light-duty fleet.

We proposed a 10 mg/mi US06 PM standard for cars, and 20 mg/mi for trucks. 

Like the FTP PM standards, the US06 PM standards are per-vehicle caps and not 

fleet averages. The comments we received ranged from suggesting a numerically 

lower standard to maintaining the standards as proposed. CARB and other 

stakeholders recommended a standard of 4 mg/mi, and the International Council on 

Clean Transportation recommended that the standards be no higher than 6 mg/mi. 

The Alliance and Global Automakers supported the proposed standards. We 

considered all of the comments suggesting various levels for these standards, and 

we are finalizing standards of 10 mg/mi through MY 2021 and of 6 mg/mi for 2022 

and later model years, for both lighter and heavier vehicles, because they reflect the 

current US06 PM performance of most vehicles. We believe these standards will 

address current poor performing vehicles and ensure that future vehicles with future 

technologies will perform, at a minimum, at or near the level of PM emissions that 

is being demonstrated by current vehicles.

Because the final standards maintain the same stringency relative to 

emission levels achieved currently, as we describe our goal for these standards in 

the proposal, there is no difference in the projected costs and benefits associated 

with the proposed and final US06 PM standard levels. The costs associated with 

meeting the final PM standards are driven by the vehicle performance over the FTP. 

That is, the 3 mg/mi FTP standard is the primary controlling factor in a vehicle’s 

overall PM performance and manufacturer compliance strategies. The US06 PM 
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standard is intended to supplement the FTP PM standard in that any additional level 

of PM control required to meet the US06 PM standard is expected to be 

accomplished through calibration and not through the use of additional hardware.

5. Higher Ethanol Content of Emissions Test Fuel 

We proposed and considered a change in the required ethanol content of 

emissions test fuel, from the current zero percent (E0) specification to a 15 percent 

ethanol (E15) specification. However, as discussed in Section IV.F above, the 

market fuel shift toward higher ethanol content has not materialized, and we are 

finalizing E10 as the Tier 3 gasoline test fuel to better match in-use fuels expected 

in the implementation timeframe of the Tier 3 standards. The adoption of E10 in 

lieu of E15 not only creates a federal test fuel that more closely reflects the ethanol 

content of in-use fuel currently and in the foreseeable future, but also more closely

aligns with California’s LEV III test fuel. 

B. Fuel Sulfur Standards

1. Annual Average Sulfur Standard

As explained in Section V.B., we believe that a 10 ppm annual average 

standard is required to enable the vehicle fleet to meet the final Tier 3 standards and 

appropriately balances feasibility with costs. Other countries and California have 

also reduced the sulfur content of their gasoline; California’s gasoline is already 

meeting our proposed 10 ppm average sulfur level, and Europe and Japan have a 

cap on the sulfur content of gasoline at 10 ppm. During the development of the 

proposed rule, we considered imposing a 10 ppm cap (i.e., no averaging, banking 

and trading), similar to the standard in Europe and Japan, as well as an average 

standard lower than 10 ppm average, because vehicle emission performance 

improves as sulfur is reduced.

However, by allowing averaging to meet 10 ppm, we believe that the most 

challenged refiners would be able to avoid what could be cost-prohibitive 

investments, while still meeting 10 ppm across the fuel pool. As discussed in 

Section VII.B., we estimate that allowing averaging would reduce nationwide 

control costs by nearly 26 percent, and would still be sufficient to enable vehicles to 

meet the proposed Tier 3 standards.

We also considered an even lower sulfur standard of 5 ppm. Based upon the 

results of our test programs and associated modeling, a sulfur standard of 5 ppm 

could reduce VOC+NOX emissions from the existing fleet by an additional 65,000 

tons in 2018.

However, we believe a 5 ppm standard would significantly increase both 

capital and operating costs. Such a standard would require: (1) more severe 

treatment of FCC gasoline; (2) treatment of additional (non-FCC) gasoline 

blendstocks; (3) essentially all refineries to reduce sulfur to 5 ppm, thereby
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eliminating much of the benefit of the ABT provisions; and potentially (4) more 

overcapacity and storage for reprocessing off-specification product. A 5 ppm 

standard would also warrant consideration of controlling the contribution to 

gasoline sulfur from gasoline additives, transmix, ethanol denaturants, and 

contamination in the distribution system.

In our analysis of the 10 ppm average standard and refineries that might 

reduce sulfur to 5 ppm in order to generate credits, we estimated that the sulfur 

control costs to achieve 5 ppm would be about twice that for our final 10 ppm

standard. This is 60 percent higher on a cost per ppm-gallon basis. The much 

higher cost is because a 5 ppm standard eliminates the practical ability for refineries 

to trade credits. That is, there would not be enough refineries overcomplying to 

generate credits and support a viable trading program. As a result, it could become 

prohibitively expensive for the more challenged refineries to comply, creating 

potential financial hardship situations. Because the costs and other economic 

impacts rise dramatically as sulfur is reduced below 10 ppm, we believe that a 10

ppm sulfur standard is the most stringent feasible standard considering technology

and cost.

Table IX-1 below summarizes the various alternative gasoline sulfur 

programs that we assessed and our estimated costs for those alternative programs. 

Table IX-1. Summary of Costs for Alternative Fuel Programs

Sulfur Level Credit Trading Per-gallon 

Cost (c/gal)

Capital Cost 

($MM)

Final Rule 

Case

10 Nationwide 0.65 2025

NPRM Case 10 Intra-company

Only

0.75 2195

No ABT Case 10 None 0.87 2990

Stringent Case 5 None 1.27 3805

Table IX-1 demonstrates that the ABT program has a profound impact on 

the cost of sulfur control. The estimated per-gallon cost and the capital costs for the 

case without an ABT program are 35 percent and 47 percent higher, respectively, 

than the final rule case which assumes nationwide credit trading. The stringent 

sulfur control case, which modeled a 5 ppm average standard and assumes no ABT 

program, is estimated to cost about twice that of the final rule case. The final rule 

case, which provides a very flexible ABT program, achieves a 10 ppm average 

sulfur standard at the lowest cost and therefore is the most cost-effective of the 

various options that we studied. 

Additionally, as discussed in Sections IV.A and V.B a standard above 10 

ppm would not be sufficiently low to meet the Tier 3 emissions standards. The 

feasibility of the 30 mg/mi NMOG+NOx fleet average depends on exhaust catalyst 

systems that require gasoline with average sulfur levels of 10 ppm or less. Further, 
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annual average sulfur levels greater than 10 ppm would significantly impair the 

emission control technology that we expect will be used to meet the Tier 3 

standards and to ensure in-use compliance over a vehicle’s useful life. This is 

particularly a concern for some larger vehicles that will need to reduce NOx to 

near-zero levels, due to greater difficulty in reducing cold-start NMOG, in order to 

meet a combined NMOG+NOx standard. As discussed in Section IV.A.6, 

increasing gasoline sulfur to 20 or 30 ppm would make it impossible for vehicle 

manufacturers to meet the Tier 3 standards. Achieving Tier 3 standards would 

require offsetting the resultant higher emissions, but EPA is not aware of existing or 

developing technology that could address these higher emissions when taking into 

consideration the entire vehicle fleet.

Thus, we believe that a standard of 10 ppm is appropriate. When combined 

with the advances in emissions control technologies, a 10 ppm average sulfur 

standard is sufficient to allow vehicles meet the Tier 3 emissions standards at the 

lowest cost.

2. Refinery Gate Sulfur Cap

In addition to lower average sulfur standards, we also considered lowering

the per-gallon cap standards. As discussed in Section V.C, we are maintaining the 

current per-gallon caps of 80 ppm at the refinery gate and 95 ppm downstream. We 

co-proposed refinery gate per-gallon cap standards of 50 ppm and 80 ppm (with 

downstream caps of 65 and 95, respectively), and we requested comment on a 

refinery gate cap of 20 ppm. 

In assessing the potential of a lower refinery gate cap of 50 ppm, we found 

that it would directionally increase the costs of the Tier 3 program. Our analysis 

shows that a 50 ppm cap would increase the cost of the Tier 3 gasoline sulfur 

standards by approximately 10 percent (see RIA Chapter 5). A cap at this level 

would result in higher capital costs for a number of refiners due to the decreased 

ability to handle off-spec product with a lower refinery gate cap. The need for 

installation of additional tankage and/or increased refinery processing capability

would also be greater, as refiners must ensure that they can continue to produce 

saleable product and meet demand in the event of an upset or an off-spec batch of 

fuel.

Additionally, the more stringent cap would unlikely provide significant 

additional emission benefits nationwide. As discussed previously in Sections III 

through V, the emissions benefits associated with the Tier 3 program are mainly

associated with the reduction in the average sulfur content of gasoline from 30 to 10 

ppm, since vehicle emissions are proportional to the sulfur content of the fuel; 

changes in the cap would not affect this. We anticipate that in most (if not all) 

cases refineries will make operational changes and/or investments in order to reduce 

their credit burden and reduce their compliance costs; thus, we anticipate that most 

refineries, including those using credits, will still average less than 20 or 30 ppm in 

their physical gasoline production. While there will certainly be some variations 
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above and below 10 ppm (just as there are today relative to the 30 ppm standard 

under the current Tier 2 program), it is not possible for us to predict them in a way

that we could quantify the associated emissions and air quality impacts. As a result, 

we cannot currently estimate the potential benefits of a 50 ppm cap. However, 

during the implementation of the program we will be monitoring in-use sulfur 

levels and further evaluating in-use sulfur levels and their impact on vehicle 

emissions. This will provide us additional information with which to evaluate the 

potential benefits of a lower sulfur cap, if warranted. 

C. Program Start Date

We are finalizing the Tier 3 vehicle emissions and fuel standards with a 

2017 start date, considering the vehicle and its fuel together as an integrated system. 

As described in Section IX.A.1 and 2, we considered different phase-ins for the 

vehicle program. We have also considered the comments requesting additional lead 

time for the fuel program. As discussed in Section V.L.3., we believe that the lead 

time provided is sufficient to meet a January 1, 2017, start date for the fuel sulfur 

standard, especially coupled with the flexibilities being offered as part of the 

program and the fact that only a few refineries will need to install grassroots 

equipment to meet the Tier 3 standards. As discussed in Section V.D, we did 

consider and are finalizing, in response to comments, a provision allowing refiners 

to carry over credits from Tier 2. 

Given that the lead time and associated programmatic flexibility we are 

finalizing is sufficient to allow industry to readily comply; we do not expect that a 

delay in the start date of the fuel standards would change the cost of compliance; 

any further delay in the program start date would simply delay the actions to 

comply. Furthermore, delaying the start of the program would forego significant 

emissions, air quality, and health benefits. Sections III and VIII describe the 

impacts of the Tier 3 standards in the year 2018. The majority of these impacts 

result from the effects of the fuel sulfur standard on the existing fleet, because there 

will be limited penetration of Tier 3 vehicles in 2018, and even those vehicles will 

not yet be meeting fully phased-in standards. Thus, the 2018 estimates of emission 

reductions, air quality improvements, and health benefits are an approximation of 

the benefits that would be foregone for each year that the program is delayed. 

Because we believe the start of the Tier 3 program is feasible and appropriate, and 

its delay would forego significant benefits, we are finalizing, as proposed, fuel 

sulfur standards that take effect January 1, 2017.

X. Economic Impact Analysis

A. Introduction

The rule will affect two sectors directly: vehicle manufacturing and 

petroleum refining. For these two regulated sectors, the economic impact analysis 

discusses the market impacts from the rule: changes in price and quantity sold. In 

addition, although analysis of employment impacts is not part of a benefit-cost 
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analysis (except to the extent that labor costs contribute to costs), employment 

impacts of federal rules are of particular concern in the current economic climate of 

sizeable unemployment. Executive Order 13563, “Improving Regulation and 

Regulatory Review” (January 18, 2011), states, “Our regulatory system must 

protect public health, welfare, safety, and our environment while promoting 

economic growth, innovation, competitiveness, and job creation” (emphasis added). 

For this reason, we are examining the effects of this rule on employment in the 

regulated sectors.

Some commenters suggest that the overall effects of Tier 3 on the economy 

are likely to be positive, because the standards encourage innovation and reduce 

emissions. In addition, they suggest that Tier 3 will lead to greater employment to 

develop the emissions control technologies and to upgrade refineries. As discussed 

further below, other commenters suggest negative impacts, especially due to the 

fuel standards. The Motor and Equipment Manufacturers Association asks that the 

regulations “be based on sound science and data and balance the public interest 

objectives with economic realities of manufacturers.” EPA has used the best 

available information in developing these standards (including the use of peer 

reviewed literature, peer reviewed models, public comments received, etc.), and has 

documented its final estimates of the economic impacts from these standards in the 

RIA. 

B. Vehicle Sales Impacts

This rule takes effect from MY 2017-2025. In the intervening years, it is 

possible that the assumptions underlying a quantitative analysis, as well as market 

conditions, might change. For this reason, we present a qualitative discussion of the 

effects on vehicle sales of the standards at the aggregate market level. Vehicle 

manufacturers are expected to comply with the standards primarily through 

technological changes to vehicles. These changes to vehicle design and 

manufacturing are expected to increase manufacturers’ costs of vehicle production. 

Section VII.A estimates the increase in vehicle costs due to the standards. 

These costs differ across years and range from $46 to $65 for cars, $73 to $88 for 

trucks and $33 to $75 for Class 2b/3 vehicles (see Section VII.A). These costs are 

small relative to the cost of a vehicle. In a fully competitive industry, these costs 

would be entirely passed through to consumers. However in an oligopolistic 

industry such as the automotive sector, these increases in cost may not fully pass 

through to the purchase price, and the consumers may face an increase in price that 

is less than the increased manufacturers’ costs of vehicle production.592 We do not 

 

592 See, for instance, Gron, A., and Swenson, D. (2000), Cost Pass-Through in the U.S. Automobile 

Market. Review of Economics and Statistics 82, 316-324 (Docket EPA-HQ-OAR-2011-0135-

0056), who found significantly less than full-cost pass-through using data from 1984-1994. Using 

full-cost pass-through overstates costs and thus contributes to lower vehicle sales than using a lower 
Page 498 of 529

quantify the expected level of cost pass-through or the ultimate vehicle price 

increase consumers are expected to face, apart from noting that prices are expected 

to increase by an amount up to the increase in manufacturers’ costs.

This increase in price is expected to lower the quantity of vehicles sold. 

Given that we expect that vehicle prices will not change by more than the cost 

increase, we expect that the decrease in vehicle sales will be negligible. 

The effect of this rule on the use and scrappage of older vehicles is related to 

its effects on new vehicle prices and the total sales of new vehicles. The increase in 

price is likely to cause the “turnover” of the vehicle fleet (i.e., the retirement of used 

vehicles and their replacement by new models) to slow slightly, thus reducing the 

anticipated effect of the rule on fleet-wide emissions. Because we do not estimate 

the effect of the rule on new vehicle price changes nor do we have a good estimate 

of the effect of new vehicle price changes on vehicle turnover, we have not 

attempted to estimate explicitly the effects of the rule on scrappage of older vehicles 

and the turnover of the vehicle fleet.

Commenters note that the incentives to go beyond the 8-year/80,000-mile 

warranty could improve vehicle reliability and lower costs, in addition to improving 

air quality. Other commenters suggest that harmonizing standards across the whole 

U.S. will benefit the economy. EPA agrees that harmonized standards will simplify

manufacturing and marketing decisions for automakers. The Manufacturers of 

Emission Controls Association points out that many SULEV- and PZEV-compliant 

vehicles have already been sold in the U.S. Commenters did not raise other 

concerns with the qualitative vehicle sales analysis. 

C. Impacts on Petroleum Refinery Sector Production

The key change for refiners from the standards is more stringent sulfur 

requirements. This change to fuels is expected to increase manufacturers’ costs of 

gasoline production by about 0.65 cents per gallon (see Section VII.B).

Some commenters raise concerns about the economic burdens to refineries 

and to consumers who must buy more expensive gasoline, in part based on 

estimates of the costs of the standards as high as 6-9 cents per gallon. As discussed 

in Section VII.B. of this preamble, EPA has considered the costs to refineries and 

has estimated that the additional cost of gasoline will be about 0.65 cents per gallon. 

Though some refineries may face costs of up to 2.1 cents per gallon, and one 

refinery up to 2.8 cents per gallon, most will face much lower costs, as the 

averaging, banking, and trading provisions of the standards significantly ease the 

challenge of refineries to meet the standards. 

 

estimate. To the extent that the auto industry has become more competitive over time, full-cost passthrough may be more appropriate than a result based on this older study.
Page 499 of 529

In a perfectly competitive industry, this cost would be passed along 

completely to consumers. In an imperfectly competitive industry, as noted above, 

full cost pass-through is not necessary: firms may choose to reduce impacts on 

sales by not passing along full costs. In 2004, the Federal Trade Commission 

reported that “concentration for most levels of the petroleum industry has remained 

low to moderate.”593 Thus the assumption of competitive markets has some 

foundation in this industry. We estimate that the price increase that consumers are 

likely to face should be positive and up to the increase in manufacturers’ costs of 

gasoline production.

The Emissions Control Technology Association (ECTA) and Northeast 

States for Coordinated Air Use Management (NESCAUM) note that previous Tier 2 

standards, which required greater reductions in absolute magnitude, do not appear 

to have had measurable adverse impacts on refineries. ECTA cites a study by

Navigant Economics that found no measurable impact on gasoline price from Tier 

2. NESCAUM notes that refineries used a number of technologies and facility

improvements to achieve the standards in a cost-effective manner, and notes that the 

North American refining industry is making significant new investments in 

response to favorable long-term conditions. Small increases in gasoline price due to 

standards may be very difficult to identify, because of the natural volatility of 

gasoline prices. 

The effect of higher gasoline prices on gasoline sales is expected to be 

different over the short and long term. In the long run, in response to the increase in 

fuel costs, consumers can more easily change their driving habits, including where 

they live or what vehicles they use. Because of this, we expect that gasoline sales 

will decrease more in the long run compared to the short run as a result of the price 

increase due to the rule. However, because manufacturers’ costs are expected to 

increase less than one cent per gallon, we expect that the decrease in gasoline sales 

will be negligible over all time horizons. 

D. Employment Impacts

This section discusses changes in employment due to the rule. We focus on 

the auto manufacturing sector and the refinery sector because they are directly

regulated, and because they are likely to bear a substantial share of changes in 

employment due to this rule. We partially quantify impacts in the auto sector, 

providing a mix of qualitative and quantitative discussion, following the methods 

used in the Final Rulemaking for 2017–2025 Model Year Light-Duty Vehicle 

Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards.594 

 

593 Federal Trade Commission, Bureau of Economics. (2004). The Petroleum Industry: Mergers, 

Structural Change, and Antitrust Enforcement. Retrieved August 16, 2011from Federal Trade 

Commission website: http://www.ftc.gov/os/2004/08/040813mergersinpetrolberpt.pdf (Docket 

EPA-HQ-OAR-2011-0135-0055).

594 77 FR 62623 (October 15, 2012).
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For the refinery sector we provide a qualitative analysis. We also include 

discussion of effects on the motor vehicle parts manufacturing sector because the 

auto manufacturing sector can either produce parts internally or buy them from an 

external supplier, and we do not have estimates of the likely breakdown of effort 

between the two sectors. For the same reasons, we discuss effects on producers of 

equipment that refiners will use to comply with the standards.

Chevron Products Company states that we did not consider the economic 

context of the time when discussing our impacts. As we stated in the NPRM, we 

recognize the importance of context. When the economy is at full employment, an 

environmental regulation is unlikely to have much impact on net overall U.S. 

employment; instead, labor would primarily be shifted from one sector to another. 

These shifts in employment impose an opportunity cost on society, approximated 

by the wages of the employees, as regulation diverts workers from other activities 

in the economy. In this situation, any effects on net employment are likely to be 

transitory as workers change jobs (e.g., some workers may need to be retrained or 

require time to search for new jobs, while shortages in some sectors or regions 

could bid up wages to attract workers). 

On the other hand, if a regulation comes into effect during a period of high 

unemployment, a change in labor demand due to regulation may affect net overall 

U.S. employment because the labor market is not in equilibrium. Schmalansee and 

Stavins point out that net positive employment effects are possible in the near term 

when the economy is at less than full employment due to the potential hiring of idle 

labor resources by the regulated sector to meet new requirements (e.g., to install 

new equipment) and new economic activity in sectors related to the regulated 

sector.595 In the longer run, the net effect on employment is more difficult to 

predict and will depend on the way in which the related industries respond to the 

regulatory requirements. As Schmalansee and Stavins note, it is possible that the 

magnitude of the effect on employment could vary over time, region, and sector, 

and positive effects on employment in some regions or sectors could be offset by

negative effects in other regions or sectors. For this reason, they urge caution in 

reporting partial employment effects since it can “paint an inaccurate picture of net 

employment impacts if not placed in the broader economic context.”

A number of commenters (including unions, environmentalists, investor 

organizations, Medical Advocates for Health Air, NESCAUM, and the National 

Association of Clean Air Agencies) argue that the standards will increase 

employment, by stimulating auto companies and refiners to invest in pollution 

abatement equipment. As will be discussed further below, EPA agrees that the 

standards are likely to lead to more employment to provide abatement equipment, 

 

595 Schmalensee, R., & Stavins, R. (2011). A Guide to Economic and Policy Analysis of EPA’s 

Transport Rule” White paper commissioned by Excelon Corporation (Docket EPA-HQ-OAR2011-0135-0054).
Page 501 of 529

but employment due to production may also be reduced (although by very small 

amounts) due to incrementally higher prices for vehicles and fuel; we expect the net 

impact on employment in the regulated sectors to be small. 

Chevron Products Company states that we do not account for the hardship 

on local and regional economies due to the increase in refinery costs. Because we 

do not consider employment impacts to be large, even at local and regional scale, 

we do not expect large impacts on the economies at that scale.

ECTA argues that job impacts will be not only positive in the auto and auto 

parts sectors, but substantially more positive than EPA states, based on Regional 

Input-Output Modeling System (RIMS) multipliers that find increases of 5.9 jobs 

for every $1 million investment in new auto parts. Multiplier impacts trace the 

entire chain of job impacts associated with an expenditure, including factors such as 

changes in employment in retail establishments due to changes in workers in the 

auto sector. Because the expenditures will occur when unemployment is still high, 

ECTA argues, it is important to consider the multiplier effects of the expenditures 

that are embedded in the RIMS multipliers. As discussed above, the multiplier 

impacts of expenditures depend heavily on the state of the macroeconomy. Because 

of uncertainty over the state of the economy when the increased expenditures will 

occur, EPA has not quantified the multiplier impacts due to changes in employment 

associated with these standards. As discussed again below, some expenditures, 

perhaps especially in the refinery sector, will occur before the standards take effect, 

to get the manufacturing processes in place to meet the standards. These near-term 

expenditures may have some multiplier effects, because they are more likely to 

have their impacts during the current period of above-average unemployment. In 

contrast, the ongoing costs of complying with the standards, which contribute most 

directly to price increases, are likely to come in future years, when it is expected 

that unemployment rates will be lower.

The Mercatus Center at George Mason University recommended that we 

“acknowledge that both jobs gained and jobs destroyed are costs of the proposed 

regulation. Ideally, compliance jobs should be minimized, not viewed as a benefit 

of a regulation.” This assertion is confusing, in that it implies that any effect on 

employment, positive or negative, is costly. Marathon Petroleum Company and the 

American Petroleum Institute with the Association of Fuel and Petroleum 

Manufacturers argue that employment impacts should not be counted as benefits. 

Our analysis of the employment impacts of the standards is intended to identify

additional ways that these standards will affect the public. Employment clearly 

provides benefits to the people who are employed, and reducing unemployment is 

considered a desirable outcome in times of high unemployment. EPA disagrees that 

minimizing compliance jobs should be an independent objective of this rulemaking. 

The objective of the program is to improve air quality through reductions in vehicle 
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emissions; we provide information concerning employment impacts as part of our 

overall analysis of economic impacts from the rule.596

The Mercatus Center also requests that we consider the long-term effects of 

unemployment on workers who may lose jobs, and that we acknowledge that those 

who lose jobs may not be the same people who gain jobs. We recognize there are 

costs to workers who shift from one job to another,597 but we also note, as discussed 

further below, that we expect very small employment impacts from the standards.

After reviewing these comments, we conclude they have not identified any 

specific reason to depart from the approach to employment analysis that was used in 

the NPRM, though we here use a slightly modified theoretical framework. In the 

NPRM, we followed the theoretical structure in a study by Morgenstern, Pizer, and 

Shih (2002)598 of the impacts of regulation in employment in the regulated sectors. 

We here shift to a very similar framework by Berman and Bui.599 RIA Chapter 9.1 

provides additional background on this framework. In Berman and Bui’s (2001, p. 

274-75) theoretical model, the change in a firm’s labor demand arising from a change in 

regulation is decomposed into two main components: output and substitution effects.600

 The output effect describes how, if labor-intensity of production is held constant, a 

decrease in output generally leads to a decrease in labor demand. However, as 

noted by Berman and Bui, although it is often assumed that regulation increases 

marginal cost, and thereby reduces output, it need not be the case. A regulation 

could induce a firm to upgrade to less polluting, and more efficient equipment that 

lowers marginal production costs, for example. In such a case, output could 

theoretically increase. 

 

596 We note that employment shows up in the benefit-cost analysis through labor costs, which are 

included in the costs of achieving the standards; any increases in employment are part of the 

increased expenditures due to the standards, and decreases in employment reduce expenditures.

597 E.g., Jacobson, Louis S., Robert J. LaLonde, and Daniel G. Sullivan, “Earnings Losses of 

Displaced Workers.” American Economic Review 83(4) (1993): 685-709 (Docket EPA-HQ-OAR2011-0135).

598 Morgenstern, R., Pizer, W., & Shih, J. (2002). Jobs Versus the Environment: An Industry-Level 

Perspective. Journal of Environmental Economics and Management 43, 412-436 (Docket EPA-HQOAR-2011-0135-0057).

599 Berman, E. and L. T. M. Bui (2001). “Environmental Regulation and Labor Demand: Evidence 

from the South Coast Air Basin.” Journal of Public Economics 79(2): 265-295 (Docket EPA-HQOAR-2011-0135).

600 The authors also discuss a third component, the impact of regulation on factor prices, but 

conclude that this effect is unlikely to be important for large competitive factor markets, such as 

labor and capital. Morgenstern, Pizer and Shih (2002) use a very similar model, but they break the 

employment effect into three parts: 1) the demand effect; 2) the cost effect; and 3) the factor-shift 

effect. See Morgenstern, Richard D., William A. Pizer, and Jhih-Shyang Shih. “Jobs Versus the 

Environment: An Industry-Level Perspective.” Journal of Environmental Economics and 

Management 43 (2002): 412-436 (Docket EPA-HQ-OAR-2011-0135-0057).
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 The substitution effect describes how, holding output constant, regulation affects 

the labor-intensity of production. Although increased environmental regulation 

generally results in higher utilization of production factors such as pollution control 

equipment and energy to operate that equipment, the resulting impact on labor 

demand is ambiguous. For example, equipment inspection requirements, 

specialized waste handling, or pollution technologies that are added to the 

production process may affect the number of workers necessary to produce a unit 

of output. Berman and Bui (2001) model the substitution effect as the effect of 

regulation on pollution control equipment and expenditures that are required by the 

regulation and the corresponding change in labor-intensity of production. 

In summary, as the output and substitution effects may be both positive, 

both negative or some combination, standard neoclassical theory alone does not 

point to a definitive net effect of regulation on labor demand at regulated firms.

1. Employment Impacts in the Auto Sector

Following the Berman and Bui (2001) framework, we consider two effects 

for the auto sector: the output effect and the substitution effect.

a. The Output Effect

The output effect depends on the effects of this rule on vehicle sales. If 

vehicle sales decrease, employment associated with these activities will decrease. 

As discussed in Section X.B, we do not make a quantitative estimate on the effect 

of the rule on vehicle sales but we note that the decrease in vehicle sales is expected 

to be negligible. Thus we expect any decrease in employment in the auto sector 

through the output effect to be small as well.

b. The Substitution Effect

The output effect, above, measures the effect due to new vehicle sales only. 

The substitution effect measures the impacts due to the changes in technologies 

needed for vehicles to meet the standards, separate from the effect on output (that 

is, as though holding output constant). This effect includes both changes in 

employment due to incorporation of abatement technologies and overall changes in 

the labor intensity of manufacturing. We estimate the substitution effect by 

multiplying the ratio of workers to each $1 million of expenditures in the auto 

sector by the cost estimates for complying with the rule. This approach estimates 

the effects of increased expenditures while holding constant the labor intensity of 

manufacturing; it does not take into account changes in labor intensity due to 
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changes in the nature of production. This latter effect could either increase or 

decrease the employment impacts estimated here.601

Some of the costs of this rule will be spent directly in the auto 

manufacturing sector, but it is also likely that some of the costs will be spent in the 

auto parts manufacturing sector. We separately present the ratios for both the auto 

manufacturing sector and the auto parts manufacturing sector.

There are several public sources for estimates of employment per $1 million 

expenditures. As discussed in the RIA, EPA examines several sources for these 

estimates: the U.S. Bureau of Labor Statistics (BLS)’s Employment Requirements 

Matrix (ERM),602 the Census Bureau’s Annual Survey of Manufactures603 (ASM),

and its Economic Census. The use of these ratios has both advantages and 

limitations. It is often possible to estimate these ratios for quite specific sectors of 

the economy: for instance, it is possible to estimate the average number of workers 

in the light-duty vehicle manufacturing sector per $1 million spent in the sector, 

rather than use the ratio from another, more aggregated sector, such as motor 

vehicle manufacturing. As a result, it is not necessary to extrapolate employment 

ratios from possibly unrelated sectors. On the other hand, these estimates are 

averages for the sectors, covering all the activities in those sectors; they may not be 

representative of the labor required when expenditures are required on specific 

activities, or when manufacturing processes change sufficiently that labor intensity

changes. For instance, the ratio for the motor vehicle manufacturing sector 

represents the ratio for all vehicle manufacturing, not just for emissions reductions

associated with compliance activities. In addition, these estimates do not include 

changes in sectors that supply these sectors, such as steel or electronics producers. 

They thus may best be viewed as the effects on employment in the specific sectors 

due to the changes in expenditures in those sectors, rather than as an assessment of 

all employment changes due to these changes in expenditures.

The values used here are adjusted to remove the employment effects of 

imports through use of a ratio of domestic production to domestic sales of 0.667.604 

As discussed in the RIA, trends in the BLS ERM are used to estimate productivity

improvements over time that are used to adjust these ratios over time.

 

601 As noted above, Morgenstern et al. (2002) separate the effect of holding output constant into two 

effects: the cost effect, which holds labor intensity constant, and the factor shift effect, which 

estimates those changes in labor intensity.

602 Bureau of Labor Statistics. Employment Requirements Matrix. 

http://www.bls.gov/emp/ep_data_emp_requirements.htm (Docket EPA-HQ-OAR-2011-0135).

603 U.S. Census Bureau. Annual Survey of Manufactures. 

http://www.census.gov/manufacturing/asm/index.html (Docket EPA-HQ-OAR-2011-0135).

604 To estimate the proportion of domestic production affected by the change in sales, we use data 

from Ward’s Automotive Group for total car and truck production in the U.S. compared to total car 

and truck sales in the U.S. For the period 2001-2010, the proportion is 66.7 percent (Docket EPAHQ-OAR-2011-0135-0333).
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Table X-1 provides estimates of the substitution effect of this rule on 

employment. Chapter 2.1 of the RIA discusses the vehicle cost estimates developed 

for this rule, discussed in Section VII.A, presented in the second column. The 

maximum value for employment impacts per $1 million (2011$) (before 

adjustments for changes in productivity, after accounting for the share of domestic 

production) is 1.771 if all the additional costs are in the parts sector; the minimum 

value is 0.389, if all the additional costs are in the light-duty vehicle manufacturing 

sector. Increased costs of vehicles and parts will, by itself, and holding labor

intensity constant, be expected to increase employment between 2017 and 2025 by

some hundreds of jobs each year.

While we estimate employment impacts, measured in job-years, beginning 

with program implementation, some of these employment gains may occur earlier 

as auto manufacturers and parts suppliers hire staff in anticipation of compliance 

with the standard. A job-year is a way to calculate the amount of work needed to 

complete a specific task. For example, a job-year is one year of work for one 

person.

Table X-1 Employment Effects due to Increased Costs of Vehicles and Parts, 

in job-years

Year Costs 

(Millions of 

2010$)

Maximum Employment 

Effect (if all expenditures 

are in the Parts Sector)

Minimum Employment Effect 

(if all expenditures are in the 

Light Duty Vehicle Mfg 

Sector)

2016 $ 21 0 0 

2017 $ 297 400 100 

2018 $ 615 800 200 

2019 $ 653 800 200 

2020 $ 697 800 200 

2021 $ 725 800 200 

2022 $ 758 800 200 

2023 $ 751 800 200 

2024 $ 761 800 200 

2025 $ 773 700 200 

c. Summary of Employment Effects in the Auto Sector

The overall effect of the standards on auto sector employment depends on 

the relative magnitude of the output effect and the substitution effect. Because we 

do not have quantitative estimates of the output effect, and only a partial estimate of 

the substitution effect, we cannot reach a quantitative estimate of the overall 

employment effects of the standards on auto sector employment or even whether 

the total effect will be positive or negative. However, given that the expected 

increase in production costs to the auto manufacturers is relatively small, we expect 

that the magnitudes of all these effects will be small as well. 
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Additionally, the standards are not expected to provide incentives for 

manufacturers to shift employment between domestic and foreign production. This 

is because the increased standards of the rule will apply to vehicles sold in the U.S. 

regardless of where they are produced. If foreign manufacturers already have 

increased expertise in satisfying the requirements of the rule, there may be some 

initial incentive for foreign production, but the opportunity for domestic 

manufacturers to sell in other markets might increase. To the extent that the 

requirements of this rule might lead to installation and use of technologies that other 

countries may seek now or in the future, developing this capacity for domestic 

production now may provide some additional ability to serve those markets. This 

potential benefit for domestic production will not apply if other countries are not 

likely to have similar standards.

2. Refinery Employment Impacts

The Berman and Bui (2001) framework of output and substitution effects 

can also be applied to the impact of the rule on employment in the refinery sector. 

Here we use a fully qualitative approach. A qualitative discussion allows for a 

wider incorporation of additional considerations, such as timing of impacts and the 

effects of the rule on imports and exports. Because the discussion is qualitative, we 

do not sum the net effects on employment. 

The output effect on refining sector employment is expected to be negative. 

The discussion in Section X.C above suggested that the standards will cause a small 

decrease in the quantity of gasoline demanded due to higher production costs being 

passed through to consumers. This slightly reduced level of sales will likely have a 

negative impact on employment in the refining sector. While we do not quantify

the level of job losses that could be expected here, recall that the quantity of 

gasoline sold as a result of these standards is expected to decrease by only a very

small amount over any time horizon. 

The substitution effect of the standards on employment in the refining sector 

can be either positive or negative in the Berman and Bui framework; here, we 

expect a small, possibly positive impact. In order to satisfy the requirements of the 

rule, firms in the refining industry are expected to perform additional work that will 

require hiring more employees, especially perhaps in the short run. Section V.L.2.e

discusses the expected employment needed to reduce the sulfur content of fuels; as 

noted there, to meet the Tier 3 sulfur standards, refiners are expected to invest $2 

billion between 2012 and 2019 and utilize approximately 250 front-end design and 

engineering jobs and 1,500 construction jobs. As the petroleum sector employed 

approximately 71,000 workers in 2011, this temporary increase in employment will

be small when compared to 2011 levels.

Chevron Products Company states that we have not considered global 

competitive forces in our assessment. As we discussed in the NPRM, this rule is 

not expected to provide incentives to shift employment between domestic and

foreign production. First, the standards will apply to gasoline sold in the U.S. 
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regardless of where it has been produced. U.S. gasoline demand is projected to 

continue to decline for the foreseeable future in response to higher gasoline prices, 

more stringent vehicle and engine greenhouse gas and fuel economy standards as 

well as increased use of renewable fuels. As a result, this analysis of incentives to 

shift employment between domestic and foreign production focuses on investments 

for existing capacity instead of expanding capacity.

605

 In this case, what is relevant 

is whether the necessary modifications to comply with Tier 3 will be significantly

cheaper overseas than in the U.S. 

The main impacts on capital and operating costs to comply with Tier 3

associated with adding hydrotreating capacity are likely to be similar overseas as in 

the U.S. This is particularly true when analyzing likely sources of U.S. imports. 

The majority of gasoline imported to the U.S. today comes into the East Coast and 

is sourced out of either Europe or refineries in Canada or the Caribbean that exist 

almost solely to supply the U.S. market. These Canadian and Caribbean refineries, 

by virtue of their focus on the U.S. market, are very similar to U.S. based refineries 

and would be expected to have to incur similar capital and operating costs as their 

U.S. based competitors meeting the 10 ppm standard. Furthermore, the European 

refineries are already producing gasoline to a 10 ppm sulfur cap for Europe. To the 

extent they have refinery streams that are more difficult to hydrotreat, the U.S. 

market currently serves as an outlet for their higher sulfur gasoline streams. As a 

result, they may incur capital and operating costs on a per gallon basis at least as 

high as for their U.S. based competitors for these remaining higher sulfur gasoline 

streams. Alternatively, they may instead choose to find markets outside the U.S., 

opening the way for increased U.S. based refinery demand. 

Finally, despite refining industry projections that previously imposed diesel 

rules would lead to greater U.S. reliance on imports through major negative impacts 

on domestic refining, the reverse has actually occurred. Over the last 8 years, 

imports of gasoline and diesel fuel have continued to be the marginal supply, and 

have even dropped precipitously so that the U.S. is now a net exporter of diesel fuel 

and is importing half the gasoline that it did at its peak in 2006. With the projected 

decline in future gasoline demand in the U.S. as vehicle fuel efficiency improves, 

gasoline imports are expected to continue to decline.

Thus it is expected that for the refining sector, the output effect will lower 

employment, and the substitution effect will raise employment. As a whole then, it 

is not evident whether the standards will increase or decrease employment in the 

refining sector. However, given the small anticipated reduction in quantity sold, it 

appears that the standards will not have major employment consequences for this 

sector. 

 

605 While refinery capacity has been increasing around the world in recent years, it has been designed 

primarily to supply foreign markets other than the U.S. (e.g., increasing demand in China and India).
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The petroleum refining industry is one of the manufacturing industries 

studied by Berman and Bui (2001) when they looked at the effect of environmental 

expenditures on employment. They found that “Employment effects are very small, 

generally positive, but not statistically different from zero.” (p. 281) [Berman and 

Bui, Table 3]. Berman and Bui also state that the estimates rule out large negative 

effects (p. 282). Because most of the abatement cost of the regulations they analyze 

is incurred by refineries, in their sample, they report separate employment effects 

for refineries and non-refineries “which are also all small.” (p. 282). Berman and 

Bui suggest some explanations for the zero or small estimates, particularly for oil 

refineries: they are capital-intensive industries with relatively little employment 

when compared to other manufacturing; they face relatively inelastic demand 

because they sell output in local markets and/or because there are no unregulated 

refineries to compete with; and, finally, regulations may have been associated with 

productivity gains in petroleum refineries. We note that the regulations that these

estimates are derived from are not directly comparable to the current rule; they are 

based on the costs of reductions in refinery air pollution emissions instead of 

changing fuel properties, and therefore may not be applicable for these standards. 

The American Petroleum Institute requested that we delete reference to use of 

analysis by Morgenstern et al. (2002) because it is based on temporary construction 

jobs and a single study. We had presented that figure not as a conclusive estimate, 

but rather as one estimate that we too consider of unclear applicability to the 

standards; we have substituted Berman and Bui’s results. Several commenters cite 

a study by Navigant Economics that estimates 24,500 installation jobs during the 

first three years of the program, and 5,300 permanent jobs, associated with the 

refinery standards. These estimates include employment not just in the refinery

sector, but also multiplier effects (discussed above) for suppliers, which EPA does 

not estimate. As noted above, EPA estimates approximately 250 front-end design 

and engineering jobs and 1,500 construction jobs. 

Section 5.3 of the RIA contains some historical discussion regarding the 

impact on refineries and refining capacity of earlier rules which resulted in higher 

costs for refiners. Over the period 2003-2011, when a number of rules were being 

implemented, EIA data show a net of two refinery closures on its website. 

Meanwhile, over this same period the average size of U.S. refineries increased from 

113,000 barrels per day to 123,000 barrels per day, and total U.S. refining capacity 

increased by six percent. Thus, historically during a time when rules with much 

larger expected impacts were being implemented (the 2003 ultra-low sulfur nonroad 

diesel proposal alone was expected to have a cost impact on refineries more than 

five times greater than the current rule), U.S. refining capacity increased even as the 

number of U.S. refineries slightly fell. While closing refineries has a negative effect 

on industry employment, it is likely that the increased refining capacity at many of 

the remaining plants had a positive effect on industry employment.

The standards are also likely to have a positive impact on employment 

among producers of equipment that refiners will use to comply with the standards. 

Section V.A.2.c notes that some refiners are expected to need to revamp their 
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current treatment units, and others will need to add additional treatment units. 

Producers of this equipment will be expected to hire additional labor to meet this 

increased demand. We also note that the employment effects may be different in 

the immediate implementation phase than in the ongoing compliance phase. It is 

expected that the employment increases through the substitution effect from 

revamping old equipment and installing additional equipment should occur in the 

near term, when current unemployment levels are high, and the opportunity cost of 

workers is relatively low. Meanwhile, the employment decreases in the refining 

sector from the output effect will not start until 2017, when compliance will be 

required, and when unemployment is expected to be reduced; in a time of full 

employment, any changes in employment levels in the regulated sector are mostly

expected to be offset by changes in employment in other sectors.

XI. Public Participation

Many interested parties participated in the rulemaking process that 

culminates with this final rule. This process provided opportunity for submitting 

written public comments following the proposal that we published on May 21, 2013

(78 FR 29816), and we considered these comments in developing the final rule. In 

addition, we held public hearings on the proposed rulemaking on April 24 and 29, 

2013, and we have considered comments presented at the hearing.

Throughout the rulemaking process, EPA met with stakeholders including 

representatives from various industries (vehicle manufacturers, fuel refiners, fuel 

distributors, suppliers, engine manufacturers, etc.), states, non-governmental 

organizations, and others.

We have prepared a detailed Summary and Analysis of Comments 

document, which describes the comments we received on the proposal and our 

responses. The Summary and Analysis of Comments is available in the docket for 

this rule at the Internet address listed under ADDRESSES, as well as on the Office 

of Transportation and Air Quality Web site (http://www.epa.gov/tier3.htm). In 

addition, comments and responses for key issues are included throughout this 

preamble.

XII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive

Order 13563: Improving Regulation and Regulatory Review

Under section 3(f)(1) of Executive Order 12866 (58 FR 51735, October 4, 

1993), this action is an “economically significant regulatory action” because it is 

likely to have an annual effect on the economy of $100 million or more. 

Accordingly, EPA submitted this action to the Office of Management and Budget 

(OMB) for review under Executive Orders 12866 and 13563 (76 FR 3821, January
Page 510 of 529

21, 2011) and any changes made in response to OMB recommendations have been 

documented in the docket for this action.

In addition, EPA prepared an analysis of the potential costs and benefits 

associated with this action. This analysis is contained in Sections VII and VIII of 

this preamble and in Chapter 8 of the RIA. A copy of the analysis is available in 

the docket for this action.

B. Paperwork Reduction Act

This action is continuing existing information collection from the Tier 2 

program, with additional changes as noted below. The Office of Management and 

Budget (OMB) has previously approved the information collection requirements 

contained in the existing the existing Tier 2 gasoline rule (65 FR 6698, February 10, 

2000), under the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 

The ICRs were assigned OMB Control Numbers 2060-0437 (fuels), 2060-0104 

(light-duty vehicles), 2060-0287 (heavy-duty vehicles), and 2060-0086 (in-use 

verification program). The ICRs are being revised to reflect the changes being 

finalized today; the additional information collection requirements in this rule have 

been submitted for approval to OMB under the Paperwork Reduction Act. The 

information collection requirements are not enforceable until OMB approves them.

This rule contains reporting and recordkeeping requirements to implement

EPA’s motor vehicle certification program and the manufacturers’ in-use 

verification program (IUVP). Existing regulations require manufacturers to submit 

emissions information to EPA in conjunction with these two programs. 

Manufacturers must submit an application for emission certification prior to 

production. The application describes the major aspects of the product line, 

technical details of the emission control systems, and the results of tests to indicate 

compliance with the emissions limitations. The application and supporting test 

results are reviewed and, if appropriate, a certificate of conformity is issued. 

Subsequently, low- and high-mileage vehicles in use are tested for emissions by

manufacturers and the results of those tests reported to EPA. EPA estimates the 

total number of respondents to be 55, the total burden hours to be 73,567, and the 

total cost to respondents to be $7,690,934.

As a result of the change in certification test fuel from 9 RVP E0 to 9 RVP

E10, EPA must assess the need to make test procedure adjustments related to fuel 

economy testing such that the change in test fuel quality does not impact the 

stringency of the CAFE standards. EPA recognized that this action was needed in 

the proposed rule, but deferred proposing a specific adjustment or set of 

adjustments because the data needed to determine the value(s) for the adjustments 

was not available. Historically, manufacturers have used criteria pollutant emission 

information from the exhaust emission testing for certification as part of the data 

needed to determine fuel economy values. The final rule sets a process in motion 

for EPA to gather the information need to develop any test procedure adjustments. 

While the basic data will likely be available in late 2015 or early 2016, any rule to 
Page 511 of 529

enact potential test procedure adjustments will take additional time. During this 

interim period, any LEV III or early Tier 3 vehicles using E10 test fuel for exhaust 

emission certifications will have to be tested for fuel economy values on E0. EPA 

has studied the expected phase-in rates for these vehicles in LEV III and estimates 

that for the 2015-2017 model years there will an average about 35 additional tests 

per year for the industry with an hour burden of about 30 hours per test. Thus, over 

this three-year period, the added hour burden is 1050 hours and the sum of the cost 

of testing and the hour burden is $402,150.

This rule also contains reporting, recordkeeping, and Product Transfer 

Document (PTD) requirements for refiners and importers of motor vehicle gasoline. 

This rule contains registration, reporting, recordkeeping, and PTD requirements for 

producers and importers of denatured fuel ethanol (DFE) and other oxygenates.

This rule also contains registration, recordkeeping, and PTD requirements for 

producers of certified ethanol denaturants. This rule also contains recordkeeping 

and PTD requirements for producers of gasoline additives. The reporting, 

recordkeeping, and PTD requirements for refiners and importers of motor vehicle 

gasoline are the same requirements that exist under the Tier 2 sulfur program.606 

The registration and reporting requirements for DFE producers and importers are 

new as are the registration requirements for producers and importers of certified 

ethanol denaturants. The recordkeeping and PTD requirements for gasoline 

additive producers, DFE manufacturers, ethanol denaturant manufacturers, and 

downstream parties under the Tier 3 program are new but should be minimal since 

we expect that they are already followed as part of normal business practices. EPA 

estimates the total number of respondents to be 2,675, the total burden hours to be 

84,000 and the total cost to respondents to be $6,300,000.

Finally, this rule also contains provisions for qualifications of laboratories 

on test methods. We have adopted recordkeeping and reporting requirements that 

would apply to fuel testing laboratories. The collected data will permit EPA to: (1) 

Qualify laboratories to use test methods based upon accuracy and precision criteria 

supported by industry; and (2) Ensure that various fuels meet the standards required 

under the regulations at 40 CFR part 80 and that the associated benefits to human 

health and the environment are realized. We estimate that 750 laboratories may be 

subject to the information collection. This estimate is based upon our experience 

with qualification of laboratories under the existing diesel sulfur program. We 

estimate an annual reporting burden of 95 hours per respondent and an annual 

recordkeeping burden of 104 hours, yielding a total of 199 hours. For those 

laboratories that elect to be reference installations, the annual reporting burden 

would be 95 hours and the annual recordkeeping burden would be 128 hours. 

Burden is defined at 5 CFR 1320.3(b).

 

606 65 FR 6698, February 10, 2000; OMB Control Number: 2060-0437; EPA ICR 1907.05
Page 512 of 529

The ICR supporting statements can be found in Docket ID number EPA–

HQ–OAR–2011–0135.

An agency may not conduct or sponsor, and a person is not required to 

respond to a collection of information unless it displays a currently valid OMB 

control number. The OMB control numbers for EPA’s regulations in 40 CFR are 

listed in 40 CFR part 9. When the ICRs are approved by OMB, the Agency will 

publish a technical amendment to 40 CFR part 9 in the Federal Register to display

the OMB control numbers for the approved information collection requirements 

contained in this final rule.

We did not receive any specific comments on the ICR; comments received 

regarding compliance-related provisions are discussed above in Sections IV and V. 

C. Regulatory Flexibility Act

1. Overview

The Regulatory Flexibility Act (RFA) generally requires an agency to

prepare a regulatory flexibility analysis of any rule subject to notice and comment 

rulemaking requirements under the Administrative Procedure Act or any other 

statute unless the agency certifies that the rule will not have a significant economic 

impact on a substantial number of small entities. Small entities include small 

businesses, small organizations, and small governmental jurisdictions.

For purposes of assessing the impacts of today’s rule on small entities, small 

entity is defined as: (1) a small business as defined by the Small Business 

Administration’s (SBA) regulations at 13 CFR 121.201 (see table below); (2) a 

small governmental jurisdiction that is a government of a city, county, town, school 

district or special district with a population of less than 50,000; and (3) a small 

organization that is any not-for-profit enterprise which is independently owned and 

operated and is not dominant in its field.

The following table provides an overview of the primary SBA small 

business categories potentially affected by this regulation:

Industry NAICSa 

Code (2007)

Defined as small entity by SBA 

if less than or equal to:

Gasoline fuel refiners and 

importers

324110 1,500 employees

Ethanol producers 325193 1,000 employees

Gasoline additive manufacturers 325199, 

325998, 

424690

1,000 employees

500 employees

100 employees

Transmix processors Varied 1,500 employees

Petroleum bulk stations and 

terminals

424710 100 employees
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Other warehousing and storagebulk petroleum storage493190 $25.5 million (annual receipts)

Light-duty vehicle and light-duty 

truck manufacturers

336111,

336112

1,000 employees

Independent commercial 

importers

811111, 

811112, 

811198

$7 million (annual receipts)

Alternative fuel converters 335312,

336312,

336322,

336399,

811198

1,000 employees

750 employees

”

”

$7 million (annual receipts)

On-highway heavy-duty engine 

& vehicle (>8,500 lbs GVWR) 

manufacturers

333618,

336120,

336211,

336312

1,000 employees

”

”

750 employees

Note:

a North American Industrial Classification System

2. Background

EPA’s Tier 2 Vehicle and Gasoline Sulfur Program, which was finalized in 

February 2000, took a systems-based approach to motor vehicle pollution by setting 

standards for both passenger vehicles and their fuel (gasoline). The program set 

stricter tailpipe and evaporative emissions standards for criteria pollutants from 

vehicles beginning with model year (MY) 2004 and phasing in through 2009. The 

program also lowered the sulfur content of gasoline, to a 30 ppm refinery average, 

80 ppm per-gallon cap, and 95 ppm downstream cap; beginning in 2004 and 

phasing in through 2008. The potential to extend the phase-in for small refiners and 

approved Gasoline Phase-In Area (GPA) refiners through the end of 2010 was 

provided in the Highway Diesel Rule607 in exchange for early compliance with the 

diesel program. Similar to the Tier 2 rule, the Tier 3 program is a comprehensive, 

systems-based approach to address the impact of light-duty vehicles and certain 

heavy-duty vehicles on air quality and health.

Pursuant to section 603 of the RFA, EPA prepared an initial regulatory

flexibility analysis (IRFA) for the proposed rule and convened a Small Business 

Advocacy Review Panel to obtain advice and recommendations of representatives 

of the regulated small entities (see 78 FR 29816, May 21, 2013). A detailed 

discussion of the Panel’s advice and recommendations is found in the Panel Report, 

located in the rulemaking docket (document number: EPA-HQ-OAR-2011-0135-

0423). A summary of the Panel’s recommendations is presented at 78 FR 29994 

(May 21, 2013).

 

607 66 FR 5136 (January 18, 2001).
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As required by section 604 of the RFA, we also prepared a final regulatory 

flexibility analysis (FRFA) for today’s final rule. The FRFA addresses the issues 

raised by public comments on the IRFA, which was part of the proposal of this rule. 

The FRFA is available for review in the docket (see Chapter 10 of the RIA) and is 

summarized below.

3. Reason for Today’s Rule

This rule establishes more stringent vehicle emissions standards and reduces

the sulfur content of gasoline beginning in 2017, as part of a systems approach in 

addressing the impacts of motor vehicles and fuels on air quality and public health. 

The gasoline sulfur standards will make emission control systems more effective 

and enable more stringent vehicle emissions standards, and the vehicle standards 

will reduce vehicle tailpipe and evaporative emissions. This will result in 

significant reductions in pollutants such as ozone, particulate matter, and air toxics. 

For a more detailed discussion of the reasoning for today’s rule, please see Sections 

II and III of this preamble. The vehicle and fuel programs are further discussed in 

Sections IV and V, respectively.

4. Legal Basis for Agency Action

The Clean Air Act (CAA) authorizes EPA to establish emissions standards 

for motor vehicles to address air pollution that may reasonably be anticipated to 

endanger public health or welfare. EPA also has authority to establish fuel controls 

to address such air pollution. The authority for the vehicle emission standards 

comes from CAA section 202(a), Section 202(k) provides EPA with authority to 

issue and revise regulations applicable to evaporative emissions of hydrocarbons 

from gasoline-fueled motor vehicles, and section 206(d) authorizes EPA to establish 

methods and procedures for testing whether a motor vehicle or motor vehicle 

engine conforms with section 202 requirements. The authority for the fuel 

standards comes from section 211(c).

For more detailed information on our legal authority for today’s proposal, 

please see Sections II.A and V.M of this preamble.

5. Summary of Potentially Affected Small Entities

The table above lists industries/sectors potentially affected by the Tier 3

rule. For businesses potentially impacted by the Tier 3 vehicle standards, this 

includes vehicle manufacturers, alternative fuel converters, and independent 

commercial importers. For businesses potentially impacted by the Tier 3 gasoline 

sulfur standards, this includes gasoline refiners and importers, distributors, fuel 

additive manufacturers, transmix processors, and ethanol producers.

EPA used a variety of sources to identify which entities are appropriately 

considered “small.” EPA used the criteria for small entities developed by the Small 

Business Administration under the North American Industry Classification System 
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(NAICS) as a guide. Information about these entities comes from sources including 

the Energy Information Administration (EIA) within the U.S. Department of 

Energy, oil industry literature, EPA’s certification data, and previous rulemakings 

that have affected these industries. EPA then found employment information for 

these companies using the business information database Hoover’s Online (a 

subsidiary of Dun and Bradstreet). These entities fall under the categories listed in 

the table.

6. Reporting, Recordkeeping, and Compliance

For any emission control program, EPA must have assurances that the 

regulated products will meet the standards. The program that EPA is finalizing for 

manufacturers subject to this rule will include testing, reporting, and recordkeeping 

requirements for manufacturers of vehicles covered by the Tier 3 regulations. 

Testing requirements for these manufacturers will include certification emission 

(including deterioration factor) testing, in-use testing, and production line testing. 

Reporting requirements will include emission test data and technical data on the 

vehicles. Manufacturers must keep records of this information.

Similarly for any fuel control program, EPA must have the assurance that 

fuel produced, distributed, sold and used meets the applicable standard. The 

recordkeeping, reporting, and compliance provisions of this rule are consistent with 

those in place today for other fuel programs. Further, we will use existing 

registration and reporting systems that parties in the fuel production and distribution 

industry are already familiar with.

7. Related Federal Rules

The primary federal rules that are related to this final rule are: the Tier 2 

Vehicle/Gasoline Sulfur rulemaking (65 FR 6698, February 10, 2000), the 2017 

Light-duty Greenhouse Gas (LD GHG) rule (77 FR 62623), and the Greenhouse 

Gas Emissions Standards and Fuel Efficiency Standards for Medium- and HeavyDuty Engines and Vehicles (HD GHG) rule (76 FR 57106). 

The LD GHG and HD GHG rules are coordinated efforts by EPA and the 

National Highway Traffic Safety Administration (NHTSA) taking steps to reduce 

GHG emissions and improve fuel efficiency from on-road vehicles and engines.

8. Steps Taken to Minimize the Economic Impact on Small Entities

a. Significant Panel Findings

The Small Business Advocacy Review Panel (SBAR Panel, or the Panel) 

considered regulatory options and flexibilities to help mitigate potential adverse 

effects on small businesses as a result of this rule. During the SBREFA Panel 

process, the Panel sought out and received comments on the regulatory options and 

flexibilities that were presented to SERs and Panel members. As described below, 
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much of the Panel’s recommendations were proposed, and many of those 

flexibilities are being finalized today. (The recommendations of the Panel are also 

located in Section 9 of the SBREFA Final Panel Report, which is available in the 

public docket.)

In today’s action we are also finalizing some additional flexibilities that 

were not discussed during the Panel process.

b. Outreach with Small Entities and the Panel Process

As required by section 609(b) of the RFA, as amended by SBREFA, we 

conducted outreach to small entities and convened an SBAR Panel on August 4, 

2011 to obtain advice and recommendations of representatives of the small entities 

that would be subject to the Tier 3 requirements.

As part of the SBAR Panel process, we conducted outreach with 

representatives of small businesses that would be affected by the rule. We met with 

these SERs to discuss the potential rulemaking approaches and flexibility options to 

decrease the impact of the rulemaking on their industries. The SERs provided 

written comments to the Panel, specifically on regulatory alternatives that could 

help to minimize the rule’s impact on small businesses.

The Panel’s findings and discussions were based on the information that was 

available during the term of the Panel and issues that were raised by the SERs 

during the outreach meetings and in their comments. It was agreed that EPA should

consider the issues raised by the SERs and discussions had by the Panel itself, and 

that EPA should consider comments on flexibility alternatives that would help to 

mitigate negative impacts on small businesses to the extent legally allowable by the 

Clean Air Act. Alternatives discussed throughout the Panel process included those 

offered in previous or current EPA rulemakings, as well as alternatives suggested 

by SERs and Panel members. A full discussion of the regulatory alternatives and 

hardship provisions discussed and recommended by the Panel can be found in the 

SBREFA Final Panel Report, located in the rulemaking docket. A summary of the 

Panel’s recommendations, what the Agency proposed, and what is being finalized 

today is discussed below. (A more detailed discussion of the final provisions for 

small entities can be found in Sections IV.G and V.E.)

It should be noted that during the Panel process, two additional issues were 

discussed with SERs. EPA was considering extending the new certification fuel 

specifications to all regulatory categories of engines, vehicles, equipment, and fuel 

system components that use gasoline. This would have included a wide range of 

additional applications, including small nonroad engines used in lawn and garden 

applications, recreational vehicles such as ATVs and snowmobiles, recreational 

marine applications, on-highway motorcycles, and heavy-duty gasoline engines. In 

addition, EPA considered new volatility (Reid Vapor Pressure, or RVP) standards 

for in-use gasoline. Neither of these issues was proposed, thus the discussion of 
Page 517 of 529

Panel recommendations below does not address these issues, however they are 

addressed in the Final Panel Report.

c. Panel Recommendations, Proposed Provisions, and Provisions Being 

Finalized Today

i. Tier 3 Fuels

(1) Lead Time—Sulfur

The Panel recommended that EPA allow small refiners to postpone their 

compliance with the Tier 3 program for up to three years. EPA proposed, and is 

finalizing, this provision. Approved small refiners will have from January 1, 2017 

through December 31, 2019 to continue production of gasoline with an average 

sulfur level of 30 ppm (per the Tier 2 gasoline sulfur program). Compliance with 

the 10 ppm annual average sulfur standard will begin on January 1, 2020. As 

discussed further in Section V.D.6, small refiners may continue to generate sulfur 

credits relative to the 30 ppm sulfur standard through December 31, 2019. 

Comments received on the small refiner provisions were generally supportive of the 

proposed three-year delay. However, commenters did not agree with EPA’s 

proposal that small refiners could only generate early credits relative to the 10 ppm 

sulfur standard beginning January 1, 2017, and requested an early credit generation 

period for small refiners relative to the 30 ppm sulfur standard.

As small refiners will still be subject to the 30 ppm sulfur standard when the 

Tier 3 program begins on January 1, 2017, we are finalizing that small refiners may

continue to generate credits relative to 30 ppm through December 31, 2019. 

Additionally, from January 1, 2017 through December 1, 2019, small refiners may

split their credit generation between both the 10 ppm and 30 ppm standards 

(without double-counting). For example, during this time period, a small refiner 

with an average gasoline sulfur level of 8 ppm could generate 20 ppm-volume 

credits (30-10 ppm, relative to the 30 ppm Tier 2 sulfur standard) plus 2 ppmvolume credits (10-8 ppm, relative to the 10 ppm Tier 3 sulfur standard).

(2) Provisions for Additive Manufacturers

During the SBREFA Panel process, different requirements than those 

proposed (and being finalized today) were discussed for additive manufacturers. 

Thus, the provisions recommended by the Panel were not applicable to the 

provisions proposed and now finalized for these parties. More information on the 

Panel’s recommendations for gasoline additive manufacturers can be found in the 

Final Panel Report, located in the rulemaking docket.

We proposed that parties introducing additives to gasoline greater than 1.0 

volume percent would be required to satisfy all of the obligations of a fuel 

manufacturer, including demonstration that the finished blend meets the applicable 

sulfur specification. We also proposed a maximum sulfur contribution of 3 ppm 
Page 518 of 529

from the use of a gasoline additive added downstream of the refinery at less than 

1.0 volume percent (when added at the maximum recommended treatment rate). 

Lastly, we proposed that additive manufacturers would need to maintain records of 

their additive production quality control activities for five years.

As discussed further in Section V.C., we are finalizing the requirement that 

manufacturers of gasoline additives used downstream of the refinery at less than 1.0 

volume percent must limit the sulfur contribution to the finished gasoline from the 

use of the additive to less than 3 ppm when the additive is used at the maximum 

recommended treatment rate. For each batch of additive produced, the 

manufacturer must retain sulfur test records for five years, and must make these 

records available to EPA upon request. Parties that introduce additives to gasoline 

at over 1.0 volume percent will be required to satisfy all of the obligations of a fuel 

manufacturer, including demonstration that the finished blend meets the applicable 

sulfur specification.

(3) Refinery Gate and Downstream Caps

The Panel recommended that EPA assess and request comment on retaining 

the current Tier 2 refinery gate and downstream caps of 80 and 95 ppm, 

respectively, to help provide maximum flexibility and avoid system upsets for the 

entire refining and distribution system. The Panel also recommended that EPA 

request comment on additional refinery gate and downstream caps above 20/25 ppm 

but below 80/95 ppm. The Panel expressed concern with a refinery gate cap as low 

as 20 ppm, because such a standard could cause operational problems for small 

refiners during a refinery turnaround or an upset—a cap of this level could result in 

a refiner not being able to produce gasoline. The Panel likewise expressed concerns 

that a downstream cap of 25 ppm could cause problems for small downstream 

entities, such as transmix processors, because they may not be able to reprocess 

finished gasoline down to this level.

In the proposal, EPA co-proposed caps of 80/95 ppm and 50/65 ppm and 

took comment on caps at 20/25 ppm. However, as discussed above in Section V.C, 

we are finalizing retaining the Tier 2 80 and 95 ppm caps. Since we are retaining 

the same caps from the Tier 2 program that entities in the fuel industry are currently

complying with, we do not believe that additional flexibilities with respect to the 

refinery gate and downstream sulfur caps are needed.

(4) Hardship Provisions

The Panel recommended that EPA propose hardship provisions for all 

gasoline refiners and importers, similar to those in prior EPA fuels programs: (a) 

the extreme unforeseen circumstances hardship provision, and (b) the extreme 

hardship provision. The Panel also recommended that if EPA were to propose 

lower refinery gate and downstream caps, EPA should also consider hardship relief 

in the form of long-term relief on the sulfur cap if the circumstances both warrant it 

and can be structured in a way to allow for it. EPA proposed, and is finalizing, both 
Page 519 of 529

the extreme unforeseen circumstances and extreme hardship provisions for all 

gasoline refiners and importers. As described in Section V.E.2, hardship relief will 

be granted on a case-by-case basis following a showing that compliance (especially 

through the use of credits) is not feasible. If a hardship waiver is granted, EPA will 

determine appropriate hardship relief based on the refiner’s hardship application 

and an assessment of the credit market at that time.

ii. Tier 3 Vehicles

As discussed in Section 5 of the Panel Report, in addition to vehicle 

manufacturers, two categories that include small businesses are covered by the new 

vehicle standards: independent commercial importers (ICIs), and alternative fuel 

vehicle converters. As discussed below, EPA’s expectation at the time of the Panel 

process was to propose a set of flexibilities that would be available to all small 

entities in these three business categories as well as to small volume manufacturers 

(SVMs) that sell less than 5,000 vehicles per year. The Panel identified a number 

of entities covered by the vehicle standards that qualify as small businesses under 

the SBA definition. Six of these companies participated as SERs.

The Panel and SERs discussed several regulatory flexibility alternatives for 

small businesses that certify vehicles subject to the proposed Tier 3 emission 

standards. As described in Appendix A of the Panel Report, EPA sought comment 

from the SERs on allowing small entities to skip the Tier 3 phase-in and instead

implement Tier 3 requirements for all of their vehicles following the phase-in 

period. In addition, EPA sought comment on the following flexibilities: (1) a 

hardship relief provision that would allow these businesses to apply for additional 

time to meet the requirements, (2) use of assigned deterioration factors for 

certification purposes, and (3) reduction in the number of tests required in the 

manufacturer in-use verification testing program. SERs were generally supportive 

of these flexibility provisions. However, one SER requested that EPA consider 

providing relaxed standards for exhaust emissions in addition to the delay, and 

another SER requested that we consider eliminating some of the evaporative 

emissions testing requirements. 

The recommendations made by the Panel on these approaches are discussed 

in detail in Section XII.C of the NPRM. We consequently proposed small business 

and small volume manufacturer provisions based on these recommendations, as 

summarized in Section IV.G above. These proposed provisions consisted of

additional lead time, reduced testing requirements, and opportunities for hardship 

relief, that would help small entities to leverage technological developments by

others and to spread the availability of needed engineering, supplier, and capital 

resources. Based on the comments we subsequently received during the public 

comment period, we have improved on the proposed provisions and are finalizing 

Tier 3 vehicle provisions for small businesses and SVMs as described in detail in 

Section IV.G above, consisting of:
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 An alternative NMOG+NOx light-duty fleet average standard phase-in schedule

for small businesses and SVMs: 125 mg/mi for MYs 2017-2021, 51 mg/mi for 

MYs 2022-2027, and 30 mg/mi thereafter;

 An optional delay of Tier 3 requirements until MY 2022 for small businesses 

and SVMs;

 EPA-assigned deterioration factors for small businesses and SVMs (as well as 

for small volume test groups);

 Reduced in-use testing requirements for SVMs with annual sales under 15,000, 

including no required testing for those with annual sales under 5,000;

 A PM testing waiver for small businesses and SVMs;

 An allowance for small alternative fuel vehicle converters to meet existing OBD 

requirements (40 CFR 86.1806-05) instead of new Tier 3 requirements;

 A provision for small businesses and SVMs in hardship situations to apply for 

additional time to meet the Tier 3 standards;

 An extension of eligibility for the Tier 3 SVM provisions to small 

manufacturers that are owned by large manufacturers but are able to 

demonstrate that they are operationally independent. 

As required by section 212 of SBREFA, EPA also is preparing a Small 

Entity Compliance Guide to help small entities comply with this rule. The Small 

Entity Compliance Guide will be available on EPA’s Office of Policy’s Small 

Entity website at: http://www.epa.gov/rfa/compliance-guides.html, and on the Tier 

3 website (http://www.epa.gov/otaq/tier3.htm) 60 days after publication of the final 

rule in the Federal Register.

D. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 

1531-1538, requires Federal agencies, unless otherwise prohibited by law, to assess 

the effects of their regulatory actions on State, local, and tribal governments and the 

private sector. This rule contains a Federal mandate that may result in expenditures 

of $100 million or more for State, local, and tribal governments, in the aggregate, or 

the private sector in any one year. Accordingly, EPA has prepared under section 

202 of the UMRA a written statement of the cost-benefit analysis, which can be 

found in Section VIII of this preamble, and in Chapter 8 of the RIA.

Consistent with section 205, EPA has identified and considered a reasonable 

number of regulatory alternatives. These alternatives are described above in 

Sections IV, V, and IX of this preamble.
Page 521 of 529

This rule is not subject to the requirements of section 203 of UMRA because 

it contains no regulatory requirements that might significantly or uniquely affect 

small governments. The rule imposes no enforceable duty on any State, local or 

tribal governments. EPA has determined that this rule contains no regulatory

requirements that might significantly or uniquely affect small governments. EPA 

has determined that this rule contains a Federal mandate that may result in 

expenditures of $100 million or more for the private sector in any one year, 

however EPA believes that the program being finalized today represents the least 

costly, and least burdensome approach to achieve the statutory requirements of the 

rule. The costs and benefits associated with this rule are discussed above in Section 

VIII of this preamble, and in Chapter 8 of the RIA, as required by section 202 of the 

UMRA.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have 

substantial direct effects on the States, on the relationship between the national 

government and the States, or on the distribution of power and responsibilities 

among the various levels of government, as specified in Executive Order 13132. 

Thus, Executive Order 13132 does not apply to this action. Although Executive 

Order 13132 does not apply to this rule, EPA did consult with representatives of 

various State and local governments in developing the rule. EPA also consulted 

with representatives from the National Association of Clean Air Agencies 

(NACAA, representing state and local air pollution officials), Northeast States for 

Coordinated Air Use Management (NESCAUM, the Clean Air Association of the 

Northeast States), and the Ozone Transport Commission (OTC, a multi-state 

organization created under the CAA responsible for advising EPA on transport 

issues and for developing and implementing regional solutions to the ground-level 

ozone problem in the Northeast and Mid-Atlantic regions).

In the spirit of Executive Order 13132, and consistent with EPA policy to 

promote communications between EPA and State and local governments, EPA 

specifically solicited comment on the proposed action from State and local officials. 

These comments are in the rulemaking docket and are summarized in the Summary

and Analysis of Comments document.

F. Executive Order 13175: Consultation and Coordination with Indian Tribal 

Governments

This action does not have tribal implications, as specified in Executive 

Order 13175 (65 FR 67249, November 9, 2000). This rule will be implemented at 

the Federal level and will impose compliance costs only on those in the gasoline 

production, distribution, and additive industry and in the engine and vehicle 

manufacturing industries. Tribal governments will be affected only to the extent 

they purchase and use regulated fuels, vehicles, and equipment. Thus, Executive 

Order 13175 does not apply to this action.
Page 522 of 529

Although Executive Order 13175 does not apply to this action, EPA 

specifically solicited additional comment from tribal officials in developing this 

action (however we did not receive any comments).

G. Executive Order 13045: Protection of Children from Environmental 

Health Risks and Safety Risks

This action is subject to EO 13045 (62 FR 19885, April 23, 1997) because it 

is an economically significant regulatory action as defined by EO 12866, and EPA 

believes that the environmental health or safety risk addressed by this action may 

have a disproportionate effect on children. Accordingly, we have evaluated the 

environmental health or safety effects of air pollutants affected by the Tier 3 

program on children. The results of this evaluation are contained in Section II.B and 

associated references.

Children are more susceptible than adults to many air pollutants because of 

differences in physiology, higher per body weight breathing rates and consumption, 

rapid development of the brain and bodily systems, and behaviors that increase 

chances for exposure. Even before birth, the developing fetus may be exposed to 

air pollutants through the mother that affect development and permanently harm the 

individual.

Infants and children breathe at much higher rates per body weight than 

adults, with infants under one year of age having a breathing rate up to five times 

that of adults.608 In addition, children breathe through their mouths more than 

adults and their nasal passages are less effective at removing pollutants, which leads 

to a higher deposition fraction in their lungs.609

Certain motor vehicle emissions present greater risks to children as well. 

Early lifestages (e.g., children) are thought to be more susceptible to tumor 

development than adults when exposed to carcinogenic chemicals that act through a 

mutagenic mode of action.610 Exposure at a young age to these carcinogens could 

lead to a higher risk of developing cancer later in life. 

The adverse effects of individual air pollutants may be more severe for 

children, particularly the youngest age groups, than adults. The Integrated Science 

 

608 U.S. Environmental Protection Agency. (2009). Metabolically-derived ventilation rates: a revised 

approach based upon oxygen consumption rates. Washington, DC: Office of Research and 

Development. EPA/600/R–06/129F. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=202543.

609 Foos, B.; Marty, M.; Schwartz, J.; Bennet, W.; Moya, J.; Jarabek, A.M.; Salmon, A.G. (2008) 

Focusing on children’s inhalation dosimetry and health effects for risk assessment: an introduction. J 

Toxicol Environ Health 71A: 149–165.

610 U.S. Environmental Protection Agency. (2005). Supplemental guidance for assessing 

susceptibility

from early-life exposure to carcinogens. Washington, DC: Risk Assessment Forum. EPA/630/

R-03/003F. http://www.epa.gov/raf/publications/pdfs/childrens_supplement_final.pdf
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Assessments and Criteria Documents for a number of pollutants affected by this 

rule, including those for NO2, SO2, PM, ozone and CO, describe children as a group 

with greater susceptibility. Section II.B.6 discusses a number of childhood health 

outcomes associated with proximity to roadways, including evidence for 

exacerbation of asthma symptoms and suggestive evidence for new onset asthma. 

In general, these studies do not identify the specific contaminants associated with 

adverse effects, instead addressing the near-roadway environment as one containing 

numerous exposures potentially associated with adverse health effects.

There is substantial evidence that people who live or attend school near 

major roadways are more likely to be of a minority race, Hispanic ethnicity, and/or 

low SES. Within these highly exposed groups, children’s exposure and 

susceptibility to health effects is greater than adults due to school-related and 

seasonal activities, behavior, and physiological factors.

Section III.C describes the ambient air quality changes resulting from the 

proposed standards, which represent levels to which the general population is 

exposed. Children are not expected to experience greater ambient concentrations of 

air pollutants than the general population. However, because of their greater 

susceptibility to air pollution and their increased time spent outdoors, it is likely that 

the proposed standards would have particular benefits for children’s health.

H. Executive Order 13211: Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use

Executive Order 13211, “Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355 (May 22, 

2001)), requires EPA to prepare and submit a Statement of Energy Effects to the 

Administrator of the Office of Information and Regulatory Affairs, Office of 

Management and Budget, for certain actions identified as “significant energy

actions.” Section 4(b) of Executive Order 13211 defines “significant energy

actions” as “any action by an agency (normally published in the Federal Register) 

that promulgates or is expected to lead to the promulgation of a final rule or 

regulation, including notices of inquiry, advance notices of proposed rulemaking, 

and notices of proposed rulemaking: (1)(i) that is a significant regulatory action 

under Executive Order 12866 or any successor order, and (ii) is likely to have a 

significant adverse effect on the supply, distribution, or use of energy; or (2) that is 

designated by the Administrator of the Office of Information and Regulatory

Affairs as a significant energy action.” Given the flexibilities being finalized for 

entities in the gasoline production and distribution system, we believe that these 

mitigate any potential adverse effects on gasoline supply and distribution. 

Although EPA does not expect this rule to have significant adverse effects on the 

supply or distribution of gasoline, we have prepared a Statement of Energy Effects 

for this action as follows.

This rule’s potential effects on energy supply, distribution, or use have been 

analyzed and are further discussed above in:
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 Section V—fuel provisions of the rule and flexibilities, including 

hardship provisions.

 Section VII.B—estimated costs of the fuel program.

 Section X—economic impacts (specifically, Section X.C for fuel 

economic impacts, and Section X.D on employment impacts).

Given the estimated costs and impacts of the Tier 3 program, as discussed in 

this preamble and in the RIA, we do not expect this rule to have an adverse effect 

on the supply or distribution of gasoline. This judgment is based on a comparison 

of the estimated impacts of the Tier 3 program to those required for the Tier 2 

program, and a review of gasoline supply during the phase-in of the Tier 2 gasoline 

sulfur program from 2003 through 2011. As the Tier 2 program reduced gasoline 

sulfur from levels as high as 450 ppm to a 30 ppm annual average, significant 

capital investments were required of many refineries to meet the 30 ppm sulfur 

standard. Both during and at the end of the Tier 2 phase-in, the U.S. gasoline 

markets did not experience a loss in gasoline supply as refiners utilized the 

flexibilities offered by the Tier 2 program to stagger investments and unit 

turnarounds/shutdowns to limit supply impacts. As discussed further in Chapter 5 

of the RIA, we do not believe that the Tier 3 program will significantly affect U.S. 

gasoline supply and/or distribution. Comments received on the proposal estimating 

the impacts of an even more stringent program than Tier 3 support this 

conclusion611. Further, we do not believe that there are any reasonable alternatives 

to the control of sulfur in gasoline which would provide the level of reduction of 

emissions, considering our cost-benefit analyses, given by the sulfur reduction 

being finalized in this rule.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement Act of 

1995 (“NTTAA”), Public Law No. 104-113 (15 U.S.C. 272 note) directs EPA to 

use voluntary consensus standards in its regulatory activities unless to do so would 

be inconsistent with applicable law or otherwise impractical. Voluntary consensus 

standards are technical standards (e.g., materials specifications, test methods, 

sampling procedures, and business practices) that are developed or adopted by

voluntary consensus standards bodies. NTTAA directs EPA to provide Congress, 

through OMB, explanations when the Agency decides not to use available and 

applicable voluntary consensus standards.

This rulemaking involves technical standards. EPA has decided to update a 

number of regulations which already contain voluntary consensus standards to more 

recent versions of these standards. EPA is finalizing use of the ASTM International 

 

611 EPA-HQ-OAR-2011-0135-4276; Attachment 7.
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(ASTM) standards listed in Table XII-1 below. The standards may be obtained 

through the ASTM Web site (www.astm.org) or by calling ASTM at (610) 832–

9585.

This rulemaking also involves environmental monitoring or measurement. 

Consistent with the Agency’s Performance Based Measurement System (“PBMS”), 

EPA has decided not to require the use of specific, prescribed analytic methods. 

Rather, the rule will allow the use of any method that meets the prescribed 

performance criteria. The PBMS approach is intended to be more flexible and costeffective for the regulated community; it is also intended to encourage innovation in 

analytical technology and improved data quality. EPA is not precluding the use of 

any method, whether it constitutes a voluntary consensus standard or not, as long as 

it meets the performance criteria specified. Comments received on this approach 

are discussed in Section VI and in the Summary and Analysis of Comments 

document.

Table XII-1 Designated Analytical Test Methods for Gasoline and Diesel Fuel

Fuel Parameter Designated Analytical Method

Sulfur in gasoline ASTM D2622-10

Sulfur in butane ASTM D6667-10

500 ppm Sulfur Diesel Fuel ASTM D2622-10

Olefins in gasoline ASTM D1319-13

Reid vapor pressure (RVP) in 

gasoline

ASTM D5191-12, with the following 

correlation equation:

RVP psi = (0.956 * X) - 0.347

RVP kPa = (0.956 * X) - 2.39

where:

X = total measured vapor pressure in psi or 

kPa

Distillation in gasoline ASTM D86-12

Benzene in gasoline ASTM D3606-10, except that instrument 

parameters shall be adjusted to ensure 

complete resolution of benzene, ethanol, and 

methanol peaks.

Aromatics in gasoline ASTM D5769-10, except that sample 

chilling requirements in section 8 of this 

standard are optional.

Oxygen and oxygenate content in 

gasoline

ASTM D5599-00 (2010)

Aromatics in diesel fuel ASTM D1319-13 

J. Executive Order 12898: Federal Actions to Address Environmental 

Justice in Minority Populations and Low-Income Populations
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Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes 

federal executive policy on environmental justice. Its main provision directs federal 

agencies, to the greatest extent practicable and permitted by law, to make 

environmental justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or environmental 

effects of their programs, policies, and activities on minority populations and lowincome populations in the United States.

EPA has determined that this final rule will not have disproportionately high 

and adverse human health or environmental effects on minority or low-income 

populations because it increases the level of environmental protection for all 

affected populations without having any disproportionately high and adverse human 

health or environmental effects on any population, including any minority or lowincome population.

This final rule will reduce emissions from vehicles across the nation, both 

new vehicles (beginning in model year 2017, when the vehicle standards start to 

apply) and existing vehicles (as soon as the lower-sulfur gasoline becomes available 

in 2017). As a result, this rule increases the level of environmental protection for 

all populations. As discussed in Section III.C.7, there is evidence that minority

populations and low-income populations live disproportionately near high-traffic 

roadways, where concentrations of many air pollutants are elevated. We expect this 

final rule to increase the level of environmental protection for these populations.

Thus, this final rule will not have a disproportionately high adverse human 

health or environmental effect on minority or low-income populations.

K. Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement Fairness Act of 1996, generally provides that 

before a rule may take effect, the agency promulgating the rule must submit a rule 

report, which includes a copy of the rule, to each House of the Congress and to the 

Comptroller General of the United States. EPA will submit a report containing this 

rule and other required information to the U.S. Senate, the U.S. House of 

Representatives, and the Comptroller General of the United States prior to 

publication of the rule in the Federal Register. A major rule cannot take effect until 

60 days after it is published in the Federal Register. This action is a “major rule” as 

defined by 5 U.S.C. 804(2). This rule will be effective on [INSERT DATE 60 

DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER].

XIII.Statutory Provisions and Legal Authority

Statutory authority for this action comes from sections 202, 203-209, 211, 

213, 216, and 301 of the Clean Air Act, 42 U.S.C. sections 7414, 7521, 7522-7525, 

7541, 7542, 7543, 7545, 7547, 7550, and 7601. Additional support for the 

procedural and compliance related aspects of this proposal, including the proposed 
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recordkeeping requirements, comes from sections 114, 208, and 301(a) of the Clean 

Air Act, 42 U.S.C. sections 7414, 7542, and 7601(a).

List of Subjects

40 CFR Part 79

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential business information, Diesel fuel, Energy, Fuel 

additives, Gasoline, Motor vehicle pollution, Penalties, Petroleum, Reporting and 

recordkeeping requirements.

40 CFR Part 80

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential Business Information, Diesel fuel, Fuel additives, 

Gasoline, Imports, Incorporation by reference, Labeling, Motor vehicle pollution, 

Penalties, Petroleum, Reporting and recordkeeping requirements.

40 CFR Part 85

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential Business Information, Imports, Labeling, Motor 

vehicle pollution, Reporting and recordkeeping requirements, Research, Warranties.

40 CFR Part 86

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential Business Information, Imports, Incorporation by

reference, Labeling, Motor vehicle pollution, Reporting and recordkeeping 

requirements, Warranties.

40 CFR Part 600

Administrative practice and procedure, Electric power, Fuel economy, 

Incorporation by reference, Labeling, Reporting and recordkeeping requirements.

40 CFR Parts 1036 and 1037

Administrative practice and procedure, Air pollution control, Confidential 

business information, Environmental protection, Labeling, Motor vehicle pollution, 

Reporting and recordkeeping requirements, Warranties.

40 CFR Part 1039

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential business information, Imports, Labeling, Penalties, 

Reporting and recordkeeping requirements, Warranties.
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40 CFR Part 1042

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential business information, Imports, Labeling, Penalties, 

Vessels, Reporting and recordkeeping requirements, Warranties. 

40 CFR Part 1048

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential business information, Imports, Labeling, Penalties, 

Reporting and recordkeeping requirements, Warranties.

40 CFR Part 1054

Environmental protection, Administrative practice and procedure, Air 

pollution control, Confidential business information, Imports, Labeling, Penalties, 

Reporting and recordkeeping requirements, Warranties.

40 CFR Parts 1065 and 1066

Environmental protection, Administrative practice and procedure, 

Incorporation by reference, Reporting and recordkeeping requirements, Research.

Dated: ____________________________

__________________________________

Gina McCarthy,

Administrator.
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