United States

Environmental Protection

Agency

Air and Radiation EPA420-R-03-004

January 2003

Final Regulatory Support

Document: Control of

Emissions from New Marine

Compression-Ignition

Engines at or Above

30 Liters per Cylinder

 Printed on Recycled Paper
EPA420-R-03-004

January 2003

Final Regulatory Support Document: Control of

Emissions from New Marine Compression-Ignition

Engines at or Above 30 Liters per Cylinder

Assessment and Standards Division

Office of Transportation and Air Quality

U.S. Environmental Protection Agency
i

Table of Contents

CHAPTER 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1 Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1.1 Standards Adopted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1.2 Projected Impacts and Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.1.3 Future Rulemaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.2 Organization of This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

1.3 Categories of Marine Diesel Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

1.4 The International Maritime Organization and MARPOL . . . . . . . . . . . . . . . . . . . . . . . 1-7

1.4.1 International Maritime Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

1.4.2 MARPOL Annex VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

1.4.3 The MARPOL Annex VI NOX Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

1.4.4 MARPOL SOx Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

1.4.5 Continuing Action at the IMO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

CHAPTER 2: Health and Welfare Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.1 Inventory Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.1.1 National Inventory - Category 3 Marine Diesel Engines . . . . . . . . . . . . . . . . . . . 2-1

2.1.2 Category 3 Inventories for Specific Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

2.1.3 Category 3 Emissions in Nonport Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

2.1.4 Category 3 Contribution by flag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

2.1.5 Category 1 and Category 2 Inventory Estimates . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

2.2 Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

2.2.1 General Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

2.2.2 Health and Welfare Effects of Ozone and Its Precursors . . . . . . . . . . . . . . . . . . 2-14

2.2.3 Ozone Nonattainment and Contribution to Ozone Nonattainment . . . . . . . . . . 2-17

2.2.4 Additional Health and Welfare Effects of NOx Emissions . . . . . . . . . . . . . . . . 2-18

2.3 Particulate Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

2.3.1 General Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

2.3.2 Health and Welfare Effects of PM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

2.3.3 PM Nonattainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

2.3.4 Diesel Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2.4 Carbon Monoxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2.4.1 General Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2.4.2 Health Effects of CO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

2.4.3 CO Nonattainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

2.5 Visibility Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26

2.5.1 General Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26

2.5.2 Visibility Impairment Where People Live, Work and Recreate . . . . . . . . . . . . 2-27

CHAPTER 3: Industry Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33

3.1 Description of Category 3 Marine Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33

3.2 Category 3 Marine Engine Manufacturers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35

3.2.1 Companies That Make Category 3 Marine Engines . . . . . . . . . . . . . . . . . . . . . . 3-35
ii

3.2.2 Production of Category 3 Marine Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36

3.2.3 Relationship Among Worldwide Engine Manufacturers . . . . . . . . . . . . . . . . . . 3-38

3.3 Vessel Manufacturers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-39

3.3.1 United States Vessel Manufacturers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-39

3.3.2 International Vessel Manufacturers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-47

3.4 U.S. Fleet Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-47

3.4.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-47

3.4.2 U.S. Fleet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-47

3.4.3 Foreign Vessels that Enter U.S. Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-48

3.4.4 Cruise Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-48

3.5 U.S. Port Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-49

3.5.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-49

3.5.2 Cruise Ship Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-51

3.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-52

CHAPTER 4: Tier 1 Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1 Marine Engine Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1.1 Diesel Engine Emission Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1.2 Category 3 Marine Engine Design and Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

4.1.3 Anticipated Technology to Meet Emission Standards . . . . . . . . . . . . . . . . . . . . . 4-4

4.1.4 Description of Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

4.2 Technology Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

4.3 Emission Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

4.4 Impact on Noise, Energy, and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

4.5 Category 1 and 2 Marine Engines Greater Than 2.5 Liters/Cylinder . . . . . . . . . . . . . 4-14

CHAPTER 5: Advanced Emission-Control Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

5.1 Water Introduction into the Combustion Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

5.1.1 Description of the Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

5.1.2 Issues to Resolve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

5.2 Selective Catalytic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

5.2.1 Description of the Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

5.2.2 Issues to Resolve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

5.3 Fuel Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

5.4 Other Engine Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

5.5 Category 1 and Category 2 Marine Diesel Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

5.6 PM Emission Control from Category 3 Marine Diesel Engines . . . . . . . . . . . . . . . . . . 5-9

Appendix to Chapter 5: Current DWI and SCR Installations . . . . . . . . . . . . . . . . . . . . . . 5-11

CHAPTER 6: Estimated Costs for Advanced Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

6.1 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

6.2 Technology Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

6.2.1 Fuel Injection Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

6.2.2 Engine Modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

6.2.3 Direct Water Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

6.2.4 Selective Catalytic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
iii

6.2.5 Fuel Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12

6.3 Total Engine Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15

6.3.1 Distribution of Category 3 Marine Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15

6.3.2 Projected Composite Costs for Category 3 Engines . . . . . . . . . . . . . . . . . . . . . 6-15

CHAPTER 7: Inventory Baseline and Projections for Advanced Technology . . . . . . . . . . . . . 7-1

7.1 Baseline Inventories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.1.1 Geographic Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.1.2 Ports Inventories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

7.1.3 Non-Port Inventories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

7.2 Future Year Baseline Inventory Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

7.3 Estimated Effects of Advanced Technology Standards on Inventories . . . . . . . . . . . . . 7-7

7.4 Per-Vessel Emission Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10

7.5 Cost Per Ton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10

CHAPTER 8: Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

8.1 Certification Test Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

8.1.1 Duty Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

8.1.2 Test Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

8.1.3 Sampling Procedures and Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

8.1.4 Modifications to the NOx Technical Code Test Procedures . . . . . . . . . . . . . . . . 8-4

8.2 Shipboard NOx Emission Measurement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

8.2.1 System Description and Component Specifications . . . . . . . . . . . . . . . . . . . . . . . 8-6

8.2.2 Emission Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
iv
v

List of Acronyms

g/m3 micrograms per cubic meter

ASTM American Society for Testing and Materials

BSFC brake-specific fuel consumption

CIMAC Conseil International Des Machines A Combustion (International

Council on Combustion Engines)

CO carbon monoxide

COHb carboxyhemoglobin

cSt centistokes

DI direct injection

DWT dead-weight tonnage

EF emission factor

EGR exhaust gas recirculation

EIAPP Engine International Air Pollution Prevention 

EPA U.S. Environmental Protection Agency

g/kW-hr grams per kilowatt-hour

GmbH Gesellschaft mit beschränkter Haftung

HC hydrocarbon

IAPP International Air Pollution Prevention 

IMO International Maritime Organization

kPa kilopascals

m/s meters per second

MARAD Maritime Administration

MARPOL the International Convention on the Prevention of Pollution from

Ships, 1973, as Modified by the Protocol of 1978 Relating Thereto 

MEPC Marine Environment Protection Committee

NAAQS National Ambient Air Quality Standards

NIST National Institute of Standards and Technology

NO2 nitrogen dioxide

NOx oxides of nitrogen

NPV net present value

NTC NOx Technical Code

OAQPS Office of Air Quality Planning and Standards

OMB Office of Management and Budget

OPA 90 Oil Pollution Act of 1990 

PM particulate matter
vi

ppm parts per million

ppmS parts per million sulfur

R&D research and development

RPE retail-price equivalent

RSZ Reduced-speed zones

SAE Society of Automotive Engineers

SCR selective catalytic reduction

SECA SOx Emission Control Area

SIC Standard Industrial Classification

SIP State Implementation Plan

SO2 sulfur dioxide

SOx oxides of sulfur

VOC volatile organic compound

wt% weight percent
Chapter 1: Introduction

a

Today’s rule applies to “new” marine diesel engines and to “new” marine vessels that

include marine diesel engines. In general, a “new” marine diesel engine or a “new” marine

vessel is one that is produced for sale in the United States or that is imported into the United

States. The emission standards established in today’s rule, therefore, will typically apply to

marine diesel engines that are installed on vessels flagged or registered in the United States.

1-1

CHAPTER 1: Introduction

At the Environmental Protection Agency (EPA), we are adopting national emission standards

for the first time for new marine diesel engines with per-cylinder displacement of 30 liters or

more that are installed on vessels flagged or registered in the United States.a These engines, also

known as Category 3 marine diesel engines, are very large engines used primarily for propulsion

power on ocean-going marine vessels such as container ships, tankers, bulk carriers, and cruise

ships. Category 3 marine diesel engines have not previously been regulated under our nonroad

engine programs. This Final Regulatory Support Document provides technical, economic, and

environmental analyses for this emission-control program. 

We are also adopting standards for new marine diesel engines with per-cylinder displacement

of 2.5 to 30 liters installed on vessels flagged or registered in the United States. These engines,

also known as Category 1 and Category 2 marine diesel engines, are already subject to more

stringent Tier 2 standards beginning in 2007, pursuant to a rule we finalized in 1999 (64 FR

73300, December 29, 1999; 40 CFR part 94). The standards we are finalizing, which are

currently voluntary for these engines, will be mandatory for new engines manufactured from

2004 through 2006. Our technical, economic, and environmental analysis for the standards for

these engines can be found in the Final Regulatory Impact Analysis for our 1999 rule and is not

repeated in this document.1

1.1 Executive Summary

1.1.1 Standards Adopted

The near-term Tier 1 standards we are adopting are equivalent to the internationally

negotiated NOx standards established by the International Maritime Organization (IMO) in

Annex VI to the International Convention on the Prevention of Pollution from Ships, 1973, as

Modified by the Protocol of 1978 Relating Thereto (more commonly referred to as MARPOL or

MARPOL 73/78; the standards are referred to as the Annex VI NOx standards).2

 The standards

are set out in Table 1.1-1. These standards are achievable almost immediately, with less than one

year of lead time, because manufacturers are already achieving and certifying to these standards

under our Voluntary Statement of Compliance program for Annex VI. These near-term

standards are being achieved through the application of currently available technology, including

optimized turbocharging, higher compression ratios, and optimized fuel injection. 
Final Regulatory Support Document

1-2

The near-term standards in this final rule will be enforceable under U.S. law for new engines

built on or after January 1, 2004. These standards will apply until we adopt a second tier of

standards in a future rulemaking. In developing that future rulemaking, which will be completed

no later than April 27, 2007, we will consider both the state of technology that may permit deeper

emission reductions and the status of international action for more stringent standards. We will

also consider whether to apply such a second tier of standards to engines on foreign vessels that

enter U.S. ports.

Table 1.1-1

NOx Emission Standards (g/kW-hr)

Engine Speed (n)

n  2000 rpm 2000 > n  130 rpm n < 130 rpm

9.8 45.0×n-0.2 17.0

We are not adopting emission standards for particulate matter (PM) from Category 3 engines

in this final rule. The majority of PM emissions from large marine diesel engines comes directly

from the high concentration of sulfur in the residual fuel they use, so the simplest way to reduce

these emissions is by removing sulfur from the fuel. Annex VI provides a mechanism to control

the sulfur content of fuels used by vessels that operate in specially designated SOx Emission

Control Areas (SECAs). After the Annex goes into force, ships operating in these designated

areas must use marine fuel with a sulfur content below 15,000 ppm or aftertreatment technology

to achieve equivalent emission reductions (for comparison, sulfur levels in marine residual fuels

may be as high as 45,000 ppm). We intend to investigate this special designation for one or more

areas in the United States. We will also reconsider this issue in our future rulemaking.

To implement these standards in an effective way, we are adopting a certification and

compliance program for Category 3 marine diesel engines that is similar but not identical to the

internationally negotiated program contained in the Technical Code on the Control of Emissions

of Nitrogen Oxides from Marine Diesel Engines (also known as the NOx Technical Code).3

 The

differences between the two programs are intended to ensure that test data be representative of

actual in-use conditions and that manufacturers demonstrate that the emission controls will be

durable for the full useful life of the engine. We specify that this useful life for Category 3

engines is three years, based on the time that engines operate before being rebuilt for the first

time. To allow manufacturers time to incorporate these changes in their testing and certification

procedures, we are adopting a provision that will allow manufacturers to certify their engines

with EPA by using the international procedures on an interim basis, after which they must use the

procedures in this final rule. 

For Category 1 and Category 2 engines, we specify certification and testing requirements

based on the requirements we adopted for these engines when we set the Tier 2 standards in

1999. Similar to the provisions for Category 3 engines, we allow manufacturers to certify their

engines using the international procedures until the Tier 2 standards apply.
Chapter 1: Introduction

1-3

We are also adopting voluntary low-emission standards, consistent with the approach we

have taken in several other programs, to encourage the introduction and more widespread use of

low-emission technologies. To be designated as a Blue Sky engine, an engine must have

emissions at least 80 percent below Annex VI NOx levels (excluding a nitrogen adjustment). 

The specific voluntary low-emission NOx standard is expressed as 9.0×n-0.2 (in g/kW-hr), with a

cap of 3.4 g/kW-hr for engines with rated speed over 130 rpm (no specific standard applies to

engines over 2000 rpm, because Category 3 engines all have engine speeds well below 2000

rpm). The engine must also have hydrocarbon (HC) and carbon monoxide (CO) emissions below

a cap of 0.4 g/kW-hr and 3.0 g/kW-hr, respectively.

1.1.2 Projected Impacts and Costs

This Final Regulatory Support Document contains our analysis of the projected impacts and

costs of applying these standards to Category 3 marine diesel engines. Similar information about

the impacts and costs of applying these standards to Category 1 and Category 2 marine diesel

engines are contained in the Final Regulatory Impact Analysis for our 1999 rule.

We expect the costs of compliance to be negligible. We do not anticipate any engineering or

design costs associated with the near-term standards because manufacturers should already be

certifying engines to the Annex VI standards to comply with the internationally negotiated

program and new Category 3 marine diesel engines installed on ships since January 1, 2000 are

widely understood to already comply with the standards set forth in both Annex VI and this rule. 

While there will be certification and compliance costs, these costs will be negligible, because

manufacturers will be able to use the same test data for both programs. The emission reductions

will reflect only reductions from engines that are currently in noncompliance with the Annex VI

NOx limits. For these reasons, the projected impacts of this rule are expected to be negligible. 

Accordingly, we have not calculated values to quantify the cost-effectiveness of the final rule. 

Table 1.1-2 shows the estimated emission inventory from Category 3 marine diesel engines.

Table 1.1-2

Category 3 Marine Vessel NOx National Emission Inventories

(Emissions from Engines on U.S. and Foreign Vessels)

1996 2010 2020 2030

No control baseline (thousand short tons) 190 303 439 659

EPA/MARPOL

Annex VI 

(thousand short tons) 190 274 367 531

Percent reduction (relative to no control) — 9.6% 16.2% 19.5%

1.1.3 Future Rulemaking

We are committing to a future rulemaking to promulgate additional engine controls that EPA

determines are appropriate under Clean Air Act section 213(a)(3). This future rulemaking will
Final Regulatory Support Document

1-4

reassess the standards in place at the time using information about the feasibility of optimizing

in-cylinder controls and applying advanced NOx and PM control technologies described in

Chapter 5 to Category 3 marine diesel engines. These advanced technologies would also lead us

to consider the need for several additional provisions, such as an enhanced compliance program

and new standards to address HC, CO, and particulate-matter emissions. We intend to consider

the application of these standards to engines on foreign vessels that enter U.S. ports. We will

also include in our evaluation an assessment of the status of international action to set more

stringent standards. The standards in this final rule will remain in effect unless modified by a

future rulemaking. We are committing to take final action on appropriate standards for marine

diesel engines by April 27, 2007, and to issue a proposal no later than approximately one year

before. EPA considers this time as necessary and appropriate to properly take into consideration

additional information expected to become available about emerging technologies, as well as any

developments in the international negotiations for more stringent emission limits.

Chapter 5 of this Final Regulatory Support Document contains a description of some of the

advanced technologies we will consider in our future rulemaking. Table 1.1-3 provides a

summary of our current understanding of the potential per-engine costs for several emission

control scenarios, as detailed in Chapter 6. Table 1.1-4 summarizes the projected emission

inventories under various scenarios of adopting more stringent standards based on advanced

technologies. 

We intend to use the future rulemaking as an opportunity also to reconsider Tier 3 emission

standards for Category 1 and Category 2 standards. We proposed Tier 3 standards for these

engines on December 11, 1998 (63 FR 68508), but chose not to finalize the Tier 3 standards in

that rulemaking. Given the current and expected advances in emission-control technologies for

land-based diesel engines and the need to coordinate standards for all categories of marine

engines, we believe this may be the appropriate context and timing to reopen the proposed Tier 3

standards.
Table 1.1-3

Summary of Projected Costs per Engine for Advanced Technologya

Technology

Package

Scope of

Standards Cost Parameter

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 

DirectWaterInjection

U.S. vesselsonly

Total cost per engine(yr. 1)

$119,105 $139,153 $159,201 $156,579 $239,391 $

Total cost per engine(yr. 6 and later)

$26,486 $39,317 $52,148 $50,470 $103,469 $

Operating costs (NPV) $55,912 $84,029 $111,824 $111,824 $223,971 $

U.S. andforeignvessels

Total cost per engine(yr. 1)

$49,157 $69,205 $89,253 $86,631 $169,443 $

Total cost per engine(yr. 6 and later)

$26,486 $39,317 $52,148 $50,470 $103,469 $

Operating costs (NPV) $9,749 $14,651 $19,497 $19,497 $39,051 

SCR

U.S. vesselsonly

Total cost per engine(yr. 1)

$241,160 $335,899 $433,863 $435,153 $821,847 $

Total cost per engine(yr. 6 and later)

$124,155 $184,788 $247,485 $248,310 $495,795 $

Operating costs (NPV) $435,240 $642,579 $852,782 $861,574 $1,668,952 $

U.S.- andforeignvessels

Total cost per engine(yr. 1)

$198,709 $293,448 $391,412 $392,702 $779,396 $

Total cost per engine(yr. 6 and later)

$124,155 $184,788 $247,485 $248,310 $495,795 $

Operating costs (NPV) $90,500 $126,651 $163,302 $172,094 $312,868 $

aThese estimated costs reflect our understanding of the current state of technology development for these emission-control strategies. We wil

before proposing emission standards based on these technologies.
Final Regulatory Support Document

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Table 1.1-4

Estimated 2030 Emission Inventories 

under Scenarios of Applying Long-Term Emission Standards 

Scenario NOx (1000 tons) percent reduction

Baseline (Annex VI) 531 --

50% Reduction—U.S. vessels only 519 2.3%

50% Reduction—All vessels 301 43%

80% Reduction—U.S. vessels only 511 3.7%

80% Reduction—All vessels 160 70%

1.2 Organization of This Document

The remainder of this Chapter 1 contains the definitions of the categories of marine diesel

engines and a brief description of the International Maritime Organization and MARPOL Annex

VI.

As noted above, the analysis in this Final Regulatory Support Document focuses on Category

3 marine diesel engines. Chapter 2 reviews information related to the health and welfare effects

of the pollutants of concern and presents the estimated contribution of Category 3 marine diesel

engines to the nationwide inventory of these pollutants. Chapter 3 contains an overview of

Category 3 marine diesel engine manufacturers and ship builders and a broad description of the

range of engines involved and their place in the market. Chapter 4 summarizes the available

information describing the technologies that manufacturers are applying to meet the

internationally negotiated standards and the expected environmental benefits from those

standards. Chapter 5 presents the available information about advanced technologies that could

be used to achieve greater emission reductions from these engines. These technologies hold out

the potential for emission improvements in the future, after constraints on their application to

marine engines are resolved. Chapter 6 provides estimated costs of applying these technologies

to Category 3 marine diesel engines and Chapter 7 provides estimated inventory impacts of

applying them. These costs and benefits are tentative, and will be revisited in our future

rulemaking. Finally, Chapter 8 discusses issues related to new test procedures for these engines.

1.3 Categories of Marine Diesel Engines

In our 1999 final rule for commercial marine diesel engines, we defined a marine engine as

one that is installed or intended to be installed on a marine vessel. We also differentiated

between three types of marine diesel engines. As explained in the 1999 rule, this approach is

necessary because marine diesel engines are typically derivatives of land-based diesel engines

that are subject to different emission standards, testing procedures, and effective dates. The
Chapter 1: Introduction

1-7

definitions for the different categories of marine diesel engines are contained in 40 CFR 94.2 and

are summarized in Table 1.3-1.

Table 1.3-1

Marine Engine Category Definitions

Category Displacement per cylinder power range (kW) rpm range

1 disp. < 5 liters 

(and power > 37 kW)

37 - 2,300 1,800 - 3,000

2 5 < disp. < 30 liters 1,500 - 8,000 750 - 1,500

3 disp > 30 liters 2,500 - 80,000 60 - 900

1.4 The International Maritime Organization and MARPOL

1.4.1 International Maritime Organization

The International Maritime Organization (IMO) is an international organization created by

the United Nations in 1948. According to the convention that established it, the IMO’s purpose

is "to provide machinery for cooperation among Governments in the field of governmental

regulation and practices relating to technical matters of all kinds affecting shipping engaged in

international trade; to encourage and facilitate the general adoption of the highest practicable

standards in matters concerning maritime safety, efficiency of navigation and prevention and

control of marine pollution from ships." The Organization also provides administrative and legal

support for the committees of Member States that develop the international marine programs.4

One of the important conventions adopted by the Member States of the IMO is the

International Convention on the Prevention of Pollution from Ships, 1973, as Modified by the

Protocol of 1978 Relating Thereto (more commonly referred to as MARPOL or MARPOL

73/78).5 This Treaty addresses several types of pollution associated with ships. The

requirements for each of these are contained in Annexes to the Treaty. They are:

• Annex I – discharge of oil 

• Annex II – noxious liquid substances

• Annex III – packaged goods 

• Annex IV – sewage (the U.S. has not ratified this Annex)

• Annex V – garbage 

• Annex VI – air emissions

1.4.2 MARPOL Annex VI

In response to growing international concern about air pollution and in recognition of the

highly international nature of maritime transportation, the International Maritime Organization
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1-8

initiated development of international standards for NOX, SOx, and a variety of other air

emissions arising from marine vessel operations. As a result of these discussions Annex VI was

drafted between 1992 and 1997 and was adopted by the Parties to MARPOL at a Diplomatic

Conference on September 26, 1997. Annex VI covers several kinds of air pollutants from ships,

including NOX, SOx, volatile organic compound (VOC) emissions from tanker-loading

operations, ozone-depleting chemicals (i.e., halons), and emissions from shipboard incinerators. 

As part of that conference, the Parties also passed a resolution adopting the Technical Code on

the Control of Emissions of Nitrogen Oxides from Marine Diesel Engines (also known as the

NOX Technical Code). Through Annex VI and the NOX Technical Code, the IMO created a

legal framework to control emissions from marine diesel engines and a procedure to test engines

and demonstrate compliance with the engine standards.

The Annex VI requirements are not enforceable until the Annex enters into force. As

specified in Article 6 of the Annex, it will enter into force twelve months after the date on which

not less than fifteen member states, the combined merchant fleets of which constitute not less

than 50 percent of the gross tonnage of the world’s merchant shipping, have ratified the

agreement. To date, more than four years after it was adopted, the Annex has been ratified by

only 6 countries representing about 26 percent of the world’s merchant shipping. The countries

that have ratified Annex VI are Sweden, Norway, Bahamas, Singapore, Marshall Islands, and

Liberia.6

1.4.3 The MARPOL Annex VI NOX Limits

The MARPOL Annex VI NOX limits are set out in Table 1.1-1, above. These standards

cover only NOX emissions; there are currently no international restrictions on particulate matter

(PM), HC, or CO emissions. The standards are based on engine speed and apply to engines

above 130 kW. These standards were expected to reduce NOX emissions by 30 percent when

fully phased in. More recent analysis by EPA, based on newly estimated emission factors for

these engines, indicates an expected reduction on the order of about 20 percent by 2030 when the

standards are fully phased-in, when compared with uncontrolled emissions. 

The Annex VI NOX limits apply to each diesel engine with a power output of more than 130

kW installed on a ship constructed on or after January 1, 2000, or that undergoes a major

conversion on or after January 1, 2000. The Annex does not distinguish between marine diesel

engines installed on recreational or commercial vessels and applies to engines on vessels engaged

only in domestic service as well as to engines on vessels engaged in international voyages. All

marine diesel engines above 130 kW would be subject to the standards regardless of their use. 

The test procedures for demonstrating compliance are set out in the NOX Technical Code7

. They

are based on ISO 8178 and are performed using distillate fuel. Engines can be pre-certified or

certified after they are installed onboard. After demonstrating compliance, pre-certified engines

would receive an Engine International Air Pollution Prevention (EIAPP) certificate. This

document, to be issued by the Administration of the flag country, is needed by the ship owner as

part of the process of demonstrating compliance with all the provisions of Annex VI and

obtaining an International Air Pollution Prevention (IAPP) certificate for the vessel once the
Chapter 1: Introduction

1-9

Annex goes into force. The Annex also contains engine compliance provisions based on a

survey approach according to which engines must be periodically inspected. These survey

requirements would apply after the Annex goes into force. An engine is surveyed right after it is

installed, every five years after installation, and at least once between 5-year surveys. Engines

are not required to be tested as part of a survey, however. The surveys can be done by a

parameter check, which can be as simple as reviewing the Record Book of Engine Parameters

that must be maintained for each engine and verifying that current engine settings are within

allowable limits.

The Annex requires that engines installed on a ship constructed on or after January 1, 2000

must comply with the specifications set forth in Regulation 13 of the Annex and the NOX

Technical Code. In addition, a ship owner must bring an existing engine into compliance if the

engine undergoes a major conversion on or after that date.8

 Although the Annex has not yet

entered into force and is not yet legally binding, it is widely recognized that the vast majority of

marine diesel engines manufactured and installed after January 1, 2000 meet the requirements of

the Annex. To facilitate implementation while the Annex is not yet in force and to allow engine

manufacturers to certify their engines before the Annex goes into force, we have set up a process

for manufacturers to obtain a Statement of Voluntary Compliance.9

 After Annex VI goes into

effect for the United States, we will develop a process by which an EPA-issued Statement of

Voluntary Compliance can be exchanged for an EIAPP. It should be noted that an engine

certificate (EIAPP) or Statement of Voluntary Compliance for an engine installed on a U.S.

vessel must be issued by the U.S. EPA. Marine classification or survey societies are not

authorized to issue such certificates on behalf of the U.S. government for U.S. vessels.

1.4.4 MARPOL SOx Limits

MARPOL Annex VI contains requirements for fuels used onboard marine vessels. These

requirements, which will take effect when the Annex goes into force, consist of two parts. First,

Annex VI specifies that the sulfur content of fuel used onboard ships may not exceed 45,000 ppm

(4.5 percent). Information gathered in an international monitoring program indicates refiners are

currently complying with this requirement and that the current sulfur level of marine bunker fuels

ranges between 5,000 and 45,000 ppm, with an average sulfur content of about 27,000 ppm. 

Second, the Annex provides a mechanism to designate SOx Emission Control Areas, within

which ships must either use fuel with a sulfur content not to exceed 15,000 ppm or an exhaust

gas cleaning system to reduce SOx emissions. To date, two SOx Emission Control Areas have

been designated: the North East Atlantic (North Sea, Irish Sea and English Channel) and the

Baltic Sea.

1.4.5 Continuing Action at the IMO

At the time the Annex VI NOX limits were adopted, in September 1997, several Member

States expressed concern that the NOX limits were not stringent enough and would not result in

the emission reductions they were intended to achieve. Due to the efforts of these Member

States, the Conference of the Parties adopted a resolution that provides for review of the emission
Final Regulatory Support Document

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limits with the aim of adopting more stringent limits taking into account the adverse effects of

such emissions on the environment and any technological developments in marine engines. The

Marine Environment Protection Committee (MEPC) is to review the standards at a minimum of

five-year intervals after entry into force of the Annex and, if appropriate, amend the NOX limits

to reflect more stringent controls. 

In March 2000, the United States requested the Marine Environment Protection Committee

(MEPC) to begin consideration of more stringent emission limits for marine diesel engines.10

EPA’s analysis of emission-control technology for our 1999 rulemaking indicated that more

stringent standards were feasible for all Category 1 and Category 2 marine diesel engines. 

Engine manufacturers were also beginning to investigate applying these emission-control

strategies to Category 3 marine diesel engines, as well as more advanced strategies such as water

emulsification and selective catalytic reduction. Reflecting the potential emission reductions that

could be obtained from applying these strategies to all marine diesel engines, the U.S.

recommended Annex VI Tier 2 NOX limits be set at 25 to 30 percent below the existing Annex

VI NOX limits for all engines subject to the regulation (engines above 130 kW), to go into effect

in 2007. This recommendation was discussed at the 44th session of the MEPC (London, March

2000), but the committee took no action. 

The United States will continue to promote more stringent standards at IMO and encourage

MEPC to adopt a second tier of emission limits that will reflect available technology and reduce

the impact of marine diesel engines on air quality around the world. Technology has continued

to advance since we made our request for review in 2000. We now believe that the Member

States of the IMO should consider further reductions of 50 percent or more from the NOX limits

currently stipulated under Regulation 13 of the Annex, to be applicable to engines installed on

vessels constructed on or after a date to be determined.
Chapter 1: Introduction

1-11

1.Final Regulatory Impact Analysis: Control of Emissions from Marine Diesel Engines,

November, 1999. EPA420-R-99-026. A copy of this document can be found in Docket

A-97-50, Document No. V-B-01.

2.Annex VI was adopted by a Conference of the Parties to MARPOL on September 26, 1997, but

has not yet entered into force. Copies of the conference versions of the Annex and the NOx

Technical Code on the Control of Emissions of Nitrogen Oxides from Marine Diesel Engines

(also known as the NOx Technical Code, which contains certification and compliance

procedures) can be found in Docket A-97-50, Document II-B-01. Copies of updated versions can

be obtained from the International Maritime Organization (www.imo.org)

3.See Endnote 2.

4.More information about the IMO can be found on its website, http://www.imo.org on the

“About IMO” tab.

5.More information about the MARPOL convention can be found on the IMO website,

http://www.imo.org ; go to the “About IMO” tab and click on “Conventions,” then “MARPOL

73/78.”

6. Information about Annex VI ratification can be found at www.imo.org (look under

Conventions, Status of Conventions - Complete List).

7.To obtain copies of this document, see Endnote 2, above.

8.As defined in Regulation 13 of Annex VI, a major conversion means the engine is replaced by

a new engine, it is substantially modified, or its maximum continuous rating is increased by more

than 10 percent.

9.For more information about our voluntary certification program, see “Guidance for Certifying

to MARPOL Annex VI,” VPCD-99-02. This letter is available on our website:

http://www.epa.gov/otaq/regs/nonroad/marine/ci/imolettr.pdf and in Docket A-2001-11,

Document No. II-B-01.

10.MEPC 44/11/7, Prevention of Pollution from Ships, Revision of the NOx Technical Code,

Tier 2 Emission Limits for Marine Diesel Engines at or Above 130 kW, submitted by the United

States. This document is available at Docket A-2001-11, Document No. II-A-16.

Chapter 1 References
Final Regulatory Support Document

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Chapter 2: Health and Welfare Concerns

2-1

CHAPTER 2: Health and Welfare Concerns

The engines that are subject to the standards in this final rule generate NOX, PM, CO, and

HC emissions that contribute to ozone and CO nonattainment as well as adverse health effects

associated with ambient concentrations of PM. They also contribute to visibility impairment and

regional haze. This chapter presents our estimates of the contribution these engines make to our

national air inventory. We include in this chapter estimates of pre- and post-control inventory

contributions. These estimates are described in greater detail in Chapter 7.

This chapter also describes the health and environmental effects related to these emissions. 

These pollutants cause a range of adverse health and welfare effects, especially in terms of

respiratory impairment and related illnesses and visibility impairment. Air quality modeling and

monitoring data presented in this chapter indicate that a large number of our citizens continue to

be affected by these emissions. 

2.1 Inventory Contributions

2.1.1 National Inventory - Category 3 Marine Diesel Engines

We developed baseline Category 3 vessel emission inventories under contract with E. H.

Pechan & Associates, Inc.1

 Inventory estimates were developed separately for vessel traffic

within 25 nautical miles of port areas (called “in-port” emissions) and vessel traffic outside of

port areas but within 175 nautical miles of the coastline (called “non-port” emissions). This twopart method allows us to take advantage of both the detailed port-specific information maintained

by commercial port administrations rather than relying simply on cargo movement data

maintained by the U.S. Army Corps of Engineers and the Maritime Administration. More

detailed information regarding the development of the baseline emission inventories can be

found in Chapter 7.

The in-port inventories are based on detailed emission estimates for nine specific ports for a

baseline year of 1996. The inventories were estimated using activity data for that port (number

of port calls, vessel types and typical times in different operating modes) and an emission factor

for each mode. Emission estimates for all other commercial ports (120 ports) were developed by

matching each of the other commercial ports to one of the nine specific ports. Matching was

based on characteristics of port activity, such as predominant vessel types, harbor draft and

region of the country. The detailed port emissions were then scaled for the other commercial

ports based on relative port activity. This inventory accounts for emissions that occur within a

radius of 25 miles of the port.

Because we do not have detailed information about the nature of non-port vessel traffic, we

developed the non-port emission inventories using information about cargo movements and

waterways data for 1996. In this case, the estimates are based on vessel speeds, average dead
Final Regulatory Support Document

2-2

weight tonnage per ship, assumed cargo capacity factors and an emission factors (in grams per

nautical mile) developed using cruise mode emission factors and total freight tonnage from the

nine specific ports discussed above. This inventory accounts for emissions that occur in the area

beginning at 25 nautical miles from the coasts and extending to sea 175 nautical miles.

The impact on coastal areas of emissions from marine diesel engines on vessels operating at

sea depends on the extent to which those emissions actually reach land. Pollutant transport is a

very complicated subject, and the transport distance can vary dramatically depending on a variety

of factors, including the pollutant under consideration; prevailing wind speed and direction and

other atmospheric conditions; and how far away from shore a ship is operating. There has been

little study of the transport of marine vessel NOX emissions off U.S. coasts.

In our inventory estimates work for the proposal we included all Category 3 vessel emissions

within 175 nautical miles of the U.S. coastline on the assumption that emission transport would

bring these emissions on to shore and affect U.S. ambient air quality. We requested comment on

the transport issue, including whether 175 nautical miles was the appropriate distance from shore

to consider or whether we should consider a range different from 175 nautical miles as our

primary scenario, and whether we should consider different distances from the coast for different

areas of the country. We also asked if there was additional information available to help us

assess the emission transport issue. In general, the comments received were supportive of

including all emissions within 175 nautical miles of the coast in the national emission inventory. 

While some commenters questioned this distance, we received no substantial new data or

information suggesting that a different distance would be more appropriate or that would help us

determine what distance from shore we should use in our inventory analysis. 

For the purpose of this final rule, we are including all Category 3 vessel emissions within 175

nautical miles of the U.S. coast in our emission inventory estimates. However, we acknowledge

that this emission transport issue is complex and requires further investigation. For example, as

we noted in the proposal for this rule, the U.S. Department of Defense (DoD) has presented some

information to us that suggests a different, shorter (offshore distance) limit be established rather

than the proposed 175 nautical miles as the appropriate location where emissions from marine

vessels would affect on-shore air quality. DoD's modeling work on the marine vessels issue in

Southern California led them to conclude that emissions within 60 nautical miles of shore could

make it back to the coast due to eddies and the nature of the sea-breeze effects. They note that

this distance seems to be confirmed by satellite data showing a distinct tendency for a curved line

of demarcation separating the offshore (unobstructed) or parallel ocean wind flow from a region

of more turbulent, recirculated air that would impact on-shore areas. That curved line of

demarcation was close to San Nicolas Island, which is about 60 nautical miles offshore. Studies

and published information on other coastal areas in California indicates that they experience

somewhat a narrower (perhaps 30 nautical miles) region of "coastal influence." Nevertheless,

commenters from California support a 175 nautical-mile boundary. 

Because of the continued data and modeling uncertainties surrounding this issue, we intend to

investigate this issue as part of our future rule. As part of this investigation, we will consider the
Chapter 2: Health and Welfare Concerns

2-3

special characteristics of emission transport in separate parts of the country. For example, we

expect that the Gulf Coast and East Coast areas of the United States would have their own unique

meteorological conditions that might call for different lines of demarcation between on-shore and

off-shore effects due to different prevailing winds in those parts of the country.

The 1996 NOX and PM emission inventories for the in-port and non-port areas are shown in

Table 2.1-1. We used 1996 as the starting point for this analysis because that is the most recent

year that we have detailed information available for the nine specific port areas.

Table 2.1-1

Category 3 Marine Diesel Engine 1996 Baseline Emission Inventories (thousand short tons)

Scenario NOX PM

In-port (within 25 nautical miles of coast) 101 9.3

Non-port (between 25 and 175 nautical miles of

coast)

89 7.7

Total (within 175 nautical miles of coast) 190 17

To estimate inventories for years after 1996, we developed inventory projections based on

expected increases in vessel freight movement and expected changes in vessel characteristics, as

well as fleet turnover based on 25 years as the average age of the world fleet at time of scrappage. 

We also take the internationally negotiated NOX limits into account because, although these

international NOX standards are not yet effective, most, if not all shipbuilders and shipping

companies around the world are currently complying with them, and this is a trend we expect to

continue. Our estimated emission inventories are based on the assumption that all vessels built

after 1999 (both U.S. and foreign) will comply with the MARPOL NOX limits. Table 2.1-2

shows the future year Category 3 marine diesel engine NOX and PM inventories for selected

years out to 2030, accounting for the implementation of Tier 1/ MARPOL Annex VI NOX limits. 

The ports inventories refer to the areas within 25 nautical miles of ports areas, while the nonports inventories refer to the areas outside of 25 nautical miles, but within 175 nautical miles of

the coast. More detailed information regarding the development of the future year emission

inventories can be found in Chapter 7.
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Table 2.1-2

Future Year NOX and PM Inventories for 

Category 3 Marine Diesel Engines (thousand short tons)

Year

NOX PM

Ports Non-ports All areas Ports Non-ports All areas

1996 101 89 190 9 8 17

2010 146 128 274 14 12 26

2020 196 172 367 20 16 37

2030 288 243 531 30 24 54

Baseline emission inventory estimates (total port and non-port) for the year 2000 for

Category 3 marine diesel engines are reported in Table 2.1-3. This table shows the relative

contributions of the different mobile-source categories to the overall national mobile-source

inventory. Of the total emissions from mobile sources, all Category 3 marine diesel engines

contribute about 1.5 percent of NOX and 2.6 percent of PM emissions in the year 2000.

Our draft emission projections for 2030 for Category 3 marine diesel engines show how

emissions from these engines are expected to increase over time after implementation of Tier 1/

MARPOL Annex VI NOX limits. The projections for 2030 are reported in Table 2.1-4 and

indicate that Category 3 marine diesel engines are expected to contribute 8.9 percent NOX and

7.3 percent of PM emissions in the year 2030. Population growth and the effects of other

regulatory control programs are factored into these projections. The relative importance of

uncontrolled nonroad engines in 2030 is higher than in the projections for 2000 because there are

already emission-control programs in place for the other categories of mobile sources which are

expected to reduce their emission levels. The effectiveness of all control programs is offset by

the anticipated growth in engine populations.
Chapter 2: Health and Welfare Concerns

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Table 2.1-3

Modeled Annual Emission Levels for 

Mobile-Source Categories in 2000 (thousand short tons)

Category

NOX HC CO PM

tons percent

of mobile

source

tons percent of

mobile

source

tons percent of

mobile

source

tons percent

of

mobile

source

Total for engines subject to

new standards (Category 3

engines on U.S. vessels)

28 0.2% 1 0.0% 2 0.0% 2.5 0.4%

Commercial Marine Diesel -

Category 3

214 1.6% 9 0.1% 19 0.02% 19.7 2.8%.

Commercial Marine Diesel -

Categories 1 and 2

703 5.2% 22 0.3% 103 0.1% 20 2.9%

Highway Motorcycles 8 0.1% 84 1.1% 331 0.4% 0.4 0.1%

Nonroad Industrial SI > 19 kW 308 2.3% 226 3.1% 1,734 2.3% 1.6 0.2%

Recreational SI 5 0.0% 418 5.7% 1,120 1.5% 12.0 1.7%

Recreation Marine Diesel 38 0.3% 1 0.0% 6 0.0% 1

0.1%

Marine SI Evap 0 0.0% 100 1.4% 0 0.0% 0 0.0%

Marine SI Exhaust 32 0.2% 708 9.6% 2,144 2.8% 38 5.4%

Nonroad SI < 19 kW 106 0.8% 1,460 19.8% 18,359 24.2% 50 7.1%

Nonroad Diesel 2,625 19.6% 316 4.3% 1,217 1.6% 253 35.9%

Locomotive 1,192 8.9% 47 0.6% 119 0.2% 30 4.3%

Total Nonroad 5,231 39% 3,391 46% 25,152 33% 426 60%

Total Highway 7,981 60% 3,811 52% 49,813 66% 240 34%

Aircraft 178 1% 183 3% 1,017 1% 39 6%

Total Mobile Sources 13,389 100% 7,385 100% 75,982 100% 705 100%

Total Man-Made Sources 24,532 -- 18,246 -- 97,735 -- 3,102 --

Mobile Source percent of Total

Man-Made Sources

55% -- 40% -- 78% -- 23% –
Final Regulatory Support Document

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Table 2.1-4

Modeled Annual Emission Levels for 

Mobile-Source Categories in 2030 (thousand short tons)

Category

NOX HC CO PM

tons percent

of

mobile

source

tons percent

of

mobile

source

tons percent

of

mobile

source

tons percent

of mobile

source

Total for engines subject to

new standards (Category 3

engines on U.S. vessels)a

28 0.5% 1 0.0% 2 0.0% 2.5 0.3%

Commercial Marine Diesel -

Category 3

531 8.9% 26 0.5% 57 0.05% 54.0 7.3%

Commercial Marine Diesel -

Categories 1 and 2

680 11.4% 26 0.5% 137 0.1% 20.0 2.7%

Highway Motorcycles 17 0.3% 172 3.4% 693 0.7% 1.0 0.1%

Nonroad Industrial SI > 19 kW 44 0.7% 17 0.3% 265 0.3% 2.0 0.3%

Recreational SI 20 0.3% 294 5.8% 1,843 1.9% 10.5 1.4%

Recreation Marine Diesel 52 0.9% 2 0.0% 11 0.0% 1.4 0.2%

Marine SI Evap 0 0.0% 122 2.4% 0 0.0% 0 0.0%

Marine SI Exhaust 64 1.1% 269 5.3% 2,083 2.1% 29 3.9%

Nonroad SI < 19 kW 126 2.1% 1,200 23.7% 32,310 33.3% 93 12.6%

Nonroad Diesel 1,994 33.4% 158 3.1% 1,727 1.8% 306 41.6%

Locomotive 531 8.9% 30 0.6% 119 0.1% 18 2.4%

Total Nonroad 4,059 68% 2,316 46% 39,245 40% 535 73%

Total Highway 1,648 28% 2,496 49% 56,303 58% 158 22%

Aircraft 262 4% 262 5% 1,502 2% 43 6%

Total Mobile Sources 5,969 100% 5,074 100% 97,050 100% 736 100%

Total Man-Made Sources 16,177 -- 16,094 -- 121,428 -- 3,297 --

Mobile Source percent of Total

Man-Made Sources

37% -- 32% -- 80% -- 22% --

a

These inventories are the same as for 2000 because, based on comments received, we assumed no future increase in

U.S. domestic trade.
Chapter 2: Health and Welfare Concerns

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2.1.2 Category 3 Inventories for Specific Ports

In the previous section we presented estimates of Category 3 marine diesel engine emissions

as percentages of the national mobile source inventory. However, marine vessel activity tends to

be concentrated in port areas, and thus we would expect that Category 3 marine diesel engines

would have a proportionately bigger impact on the mobile source pollution inventories of certain

port areas, particularly those with large commercial ports or those where the commercial port

activity is a large share of the economic activity of the area. Using the port-specific Category 3

inventories developed for use in our national inventory and the inventories for specific areas

developed in support of the heavy-duty on-highway 2007 rule, we developed estimates of the

contribution of Category 3 marine diesel engines to both the mobile source and total man made

NOX and PM inventories for several selected port areas, including several located in ozone

nonattainment areas. The NOX results are shown in Table 2.1-5 and the PM results are shown in

Table 2.1-6. As can be seen from these tables, the relative contribution of Category 3 marine

diesel engine pollution to mobile source and total man made pollution for these areas is expected

to increase in the future, even in the presence of the Tier 1/MARPOL Annex VI NOX limits. 

This is due both to the expected growth of shipping traffic in the future and the effect of

emissions control programs already in place for other mobile sources. Consequently, we expect

Category 3 marine diesel engines to continue to be significant contributors to ozone and PM

inventories in these areas in 2020.
Final Regulatory Support Document

2-8

Table 2.1-5

Category 3 Marine Diesel Engines NOX Inventories

as a Percentage of Total Man Made and Mobile Source NOX in Selected Port Areas

Ozone

Nonattainment

Area?

Port Area

% of Total Man-Made

NOX from C3 Engines

% of Mobile-Source 

NOX from C3 Engines

1996 2020 1996 2020a

Y Baton Rouge and New Orleans, LA 4.0 6.7 7.4 15.8

Y Los Angeles/Long Beach, CA 1.7 6.4 2.0 8.6

Y Beaumont/Port Arthur, TX 0.9 1.6 1.4 3.1

Y Houston/Galveston/Brazoria, TX 0.9 2.3 1.5 4.9

Y Baltimore/Washington DC 1.3 5.2 2.1 11.4

Y Philadelphia/Wilmington/Atlantic City 1.1 3.0 1.8 6.9

Y New York/New Jersey 0.7 3.2 1.0 6.2

N Seattle/Tacoma/Bremerton/

Bellingham, WA

3.7 17.3 4.3 26.3

N Miami/Ft. Lauderdale, FL 4.4 19.5 5.4 28.1

N Portland/Salem, OR 1.7 9.3 1.9 11.9

N Wilmington, NC 2.4 6.9 6.9 26.8

N Corpus Christi, TX 2.2 3.8 4.8 12.2

N Brownsville/Harlington/San Benito,

TX

1.7 6.0 1.8 6.6

a

For reference, the nationwide contribution of Category 3 marine diesel engines to mobile source NOX in 2020 is

projected to be 5.7 percent.
Chapter 2: Health and Welfare Concerns

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Table 2.1-6

Modeled PM Inventories as a Percentage of 

Total Man Made and Mobile Source PM in Selected Port Areas

Port Area

% of Total Man-Made 

PM from C3 Engines

% of Mobile-Source 

PM from C3 Engines

1996 2020 1996 2020a

Baton Rouge and New Orleans, LA 4.0 5.9 12.1 22.6

Los Angeles/Long Beach, CAb 1.8 4.4 3.9 10.8

Beaumont/Port Arthur, TX 2.3 4.1 7.4 18.3

Houston/Galveston/Brazoria, TX 2.0 3.8 3.3 8.5

Baltimore/Washington DC 1.0 3.0 3.2 9.6

Philadelphia/Wilmington/Atlantic City 0.7 1.2 2.8 6.3

New York/New Jersey 0.5 1.9 1.6 5.7

Seattle/Tacoma/Bremerton/Bellingham,

WA

3.4 10.6 8.5 25.5

Miami/Ft. Lauderdale, FL 7.5 19.9 10.6 28.7

Portland/Salem, OR 1.4 4.4 3.9 12.1

Wilmington, NC 2.1 3.3 8.1 22.4

Corpus Christi, TX 3.3 3.6 6.0 9.6

Brownsville/Harlington/San Benito, TX 2.0 4.6 3.1 14.9

a

For reference, the nationwide contribution of Category 3 marine diesel engines to mobile source PM in 2020 is projected

to be 5.8 percent.

b

PM nonattainment area.
Final Regulatory Support Document

2-10

Moosehorn (W)

Great Gulf (W)

Presidental Range - Dry River (W)

Acadia (NP)

Lye Brook (W)

Roosevelt-Campobello (IP)

Brigantine (W)

Shenandoah (NP)

James River Face (W)

Otter Creek (W)

Swanquarter (W) Linville Gorge (W)

Shining Rock (W)

Cohotta (W)

Joyce Kilmer - Slickrock (W)

Cape Romain 

(W)

Wolf Island (W)

Okefenokee (W)

St. Marks (W)

Everglades (NP)

Mammoth Cave (NP)

Sipsey 

(W)

Breton (W)

Caney Creek (W)

Upper Buffalo (W)

Hercules-Glades 

(W)

Mingo (W)

Seney (W)

Isle Royale 

(NP) 

Boundary Waters Canoe Area (W) Voyageurs NP Lostwood (W)

Theodore Roosevelt (NP)

Badlands (W)

Wind Cave (NP)

Wichita Mountains (W)

Big Bend 

(NP)

Guadalupe Mtns. (NP)

Carlsbad Caverns (NP)

Gila (W) Salt Creek (W)

Wheeler Peak (W) San Pedro Parks (W)

Pecos (W)

Bandelier (W)

White Mountain (W)

Bosque del Apache (W)

Rawah (W)

Mt. Zirkel(W)

Rocky Mountains (NP)

Flat

Tops

(W)

Eagles Nest (W)

Maroon Bells-Snowmass (W)

West Elk (W) Black Canyon (W)

La Garita (W)

Mesa Verde Great Sand Dunes (W) (NP)

Weminuche (W)

Arches (NP)

Canyonlands (NP)

Capital Reef (NP)

Bryce Canyon (NP) Zion (NP)

Grand Canyon (NP)

Petrified Forest (NP)

Sycamore Canyon (W)

Pine Mtn. (W) Mazatzal (W)

Sierra Ancha (W)

Mt. Baldy (W)

Bridger (W)

Fitzpatrick (W)

Grand Teton (NP)

Washakie (W)

North Absaroka (W) Yellowstone (NP)

Glacier (NP) Cabinet Mtns (W)

Bob Marshall (W)

Scapegoat (W)

Gates of the Mountain (W)

Anaconda Pintlar (W)

Red Rock Lake (W)

Medicine Lake (W)

U.L. Bend (W)

Selway Bitterroot (W)

Craters of the Moon (W)

Sawtooth (W)

Pasayten (W)

North Cascades (NP)

Glacier Peak (W)

Alpine Lakes (W)

Mt. Rainer (NP)

Goat Rocks (W)

Mt. Adams (W)

Olympic

(NP)

Mt. Hood (W) Eagle Cap (W)

Hells Canyon (W)

Mt Jefferson (W)

Mt. Washington (W)

Three Sisters (W)

Diamond 

Peak (W)

Strawberry Mt. (W)

Crater Lake (NP)

Gearhart Mt. (W)

Mountain Lakes 

(W)

Kalmiopsis (W)

Redwood (NP) Marble Mt. (W) Lava Beds (W)

South Warner (W)

Thousand Lakes (W) Jarbridge (W)

Yolla-Bolly-Middle-Eel (W)

Caribou (W)

Desolation (W)

Pt. Reyes (W)

Mokelumme (W)

Hoover (W)

Yosemite (NP)

Emigrant 

(W)

Pinnacles 

(W)

Ventana 

(W)

Kaiser (W)

Sequoia (NP)

Ansel Adams (W)

John Muir 

(W)

Superstition (W)

Chiricahua (W)

Saguaro (W)

Galiuro (W)

Dome Land (W) San Rafael (W)

San Gabriel (W)

Kings Canyon (NP)

Joshua 

Tree (W)

San Jacinto 

(W)

San Gorgonio (W)

Cucamonga (W)

Lassen Volcanic 

(NP)

Bearing Sea 

(W) Tuxedni 

(W)

Denali 

(NP)

Simeonof 

(W)

Hawaii 

Volcanoes 

(NP)

Haleakala (NP)

Chassahowitzka (W)

Map of 156 Mandatory Class I Federal Areas

Teton (W)

Agua Tibia 

(W)

Dolly Sods (W)

Great Smoky Mountains (NP)

See 40 CFR 81.401-437 for a 

listing of these areas by State

Figure 2.1-1

Note that many of these ports, and other commercial ports, are in or near Class I Areas, as

shown in Figure 2.1-1. Category 3 marine diesel engines on vessels that use these ports or the

sea lanes near them contribute to visibility degradation in these areas, particularly through their

PM emissions. The importance of Class I Areas is described in Section 2.5, below.
Chapter 2: Health and Welfare Concerns

2-11

2.1.3 Category 3 Emissions in Nonport Areas

Emissions from Category 3 marine diesel engines can also have a significant impact on

inventories in areas without large commercial ports. For example, Santa Barbara estimates that

engines on ocean-going marine vessels contribute about 37 percent of total NOx in their area (see

Table 2.1-7). These emissions are from ships that transit the area, and “are comparable to (even

slightly larger than) the amount of NOx produced onshore by cars and truck.2 By 2015 these

emissions are expected to increase 67 percent, contributing 61 percent of Santa Barbara’s total

NOx emissions. While Santa Barbara’s exact conditions may be unique due to the relative close

proximity of heavily used shipping channels to shore and the meteorological conditions in their

area, other coastal areas may also have relatively high inventory impacts from ocean-going

vessels.

Table 2.1-7

NOx Emissions, Santa Barbara County, California

Source 1999 2015

Tons/Day percent of total Tons/day percent of total

Onshore

Motor vehicles 25.95 33 9.96 13

Other mobile sources 17.27 22 14.19 18

Stationary sources 5.3 7 4.42 6

Area-wide sources 0.76 1 1.24 1

Offshore

Ships, boats 28.38 36 47.29 61

Oil and gas production 0.7 1 0.66 1

TOTAL 78.36 — 77.76 —

2.1.4 Category 3 Contribution by flag

It is important to determine how much of the Category 3 marine diesel engine pollution

inventory is contributed by U.S. flagged vessels, given that we are applying emission standards

only to U.S. flagged vessels. We estimated the relative contribution of U.S. and foreign flagged

vessels separately for port areas and nonport areas due to the fact the we had different data sets

available for each.

We estimated the proportion of total Category 3 emissions in-port attributable to U.S. flagged

vessels for the ports areas using port call data obtained from the U.S. Maritime Administration

(MARAD). These data contained all port calls in 1999 to U.S. ports by vessels of greater than
Final Regulatory Support Document

2-12

1000 gross registered tons engaged in foreign trade, including the country in which they are

flagged and the number of port calls each vessel made, but did not include port calls of vessels

engaged in U.S. domestic trade. We estimated the number of port calls made by U.S. flagged

vessels engaged in domestic trade and added those to those taken from the MARAD database. 

An analysis of the port call data shows that U.S. flagged vessels only account about 10 percent of

port calls to U.S. ports. For the lack of more detailed information regarding the breakout of U.S.

and foreign flagged vessel emissions we applied the percentage of port calls from U.S. and

foreign flagged vessels to the national ports inventories to determine the relative contributions of

each to the national ports inventories.

As just described, we estimated that 10 percent of Category 3 vessel calls to U.S. ports are

made by U.S. flagged vessels. However, we note that this estimate is a national average, and that

the percentage of port calls made by U.S. flagged vessels in any given port may well be different

than this. Such factors as the size of the port and the nature of the commodities being shipped in

and out of a given port would affect the percentage of calls made by U.S. versus foreign flagged

vessels. For example, in 1997 U.S. flagged vessels made up less than 10 percent of port calls by

ocean going vessels in the Houston-Galveston area but around 15 percent of port calls in the

South Coast of California.3,

4

To estimate the proportion of total Category 3 non-port emissions attributable to U.S. vessels,

we used new port call information provided by MARAD.5 This data showed not only whether a

vessel was U.S. or foreign flagged, but whether the vessels came from other U.S. ports or from

foreign ports. The data provided by MARAD was summary data and did not include any detailed

background information. However, given the small number of Category 3 vessels engaged in

U.S. domestic trade and the large number of port calls listed in this data as being from vessels

engaged in U.S. domestic trade, we believe the data contained a significant number of Category 2

vessels in the U.S. domestic trade category. Nonetheless, this data gives us a much better picture

of the nature of vessel traffic between ports than we had for the proposal, and we used it to

estimate that roughly 20 percent of non-port emissions come from U.S. flagged vessels.

We intend to continue researching the issue of U.S. versus foreign flagged vessel emissions

and plan to further refine our analysis in any future rulemaking efforts aimed at Category 3

vessels.

2.1.5 Category 1 and Category 2 Inventory Estimates

Inventory estimates for Category 1 and Category 2 marine diesel engines were developed for

our 1999 rulemaking and can be found in the Final Regulatory Impact Analysis for that rule.6

The standards we are adopting for engines with in-cylinder displacement of 2.5 to 30 liters are

equivalent to the internationally-negotiated NOx standards and are currently voluntary for those

engines. To comply with Annex VI, engines installed on ships since January 1, 2000 are widely

understood to already comply with those standards. Therefore, we are not adjusting our previous

emission inventory estimates for those engines.
Chapter 2: Health and Welfare Concerns

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2.2 Ozone

2.2.1 General Background

Ground-level ozone, the main ingredient in smog, is formed by complex chemical reactions

of volatile organic compounds (VOC) and NOx in the presence of heat and sunlight. Ozone

forms readily in the lower atmosphere, usually during hot summer weather. Volatile organic

compounds are emitted from a variety of sources, including motor vehicles, chemical plants,

refineries, factories, consumer and commercial products, and other industrial sources. Volatile

organic compounds also are emitted by natural sources such as vegetation. Oxides of nitrogen

are emitted largely from motor vehicles, off-highway equipment, power plants, and other sources

of combustion. Hydrocarbons (HC) are a large subset of VOC, and to reduce mobile source

VOC levels we set maximum emission standards for hydrocarbons. VOCs can also be part of the

secondary formation of PM.

The science of ozone formation, transport, and accumulation is complex. Ground-level

ozone is produced and destroyed in a cyclical set of chemical reactions involving NOx, VOC,

heat, and sunlight.7

 As a result, differences in weather patterns, as well as NOx and VOC levels,

contribute to daily, seasonal, and yearly differences in ozone concentrations and differences from

city to city. Many of the chemical reactions that are part of the ozone-forming cycle 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, resulting in

higher ambient ozone levels than typically would occur on a single high temperature day. 

Further complicating matters, ozone also can be transported into an area from pollution sources

found hundreds of miles upwind, resulting in elevated ozone levels even in areas with low local

NOx or VOC emissions.

On the chemical level, NOx and VOC are the principal precursors to ozone formation. The

highest levels of ozone are produced when both VOC and NOx emissions are present in

significant quantities on clear summer days. Relatively small amounts of NOx enable ozone to

form rapidly when VOC levels are relatively high, but ozone production is quickly limited by

removal of the NOx. Under these conditions, NOx reductions are highly effective in reducing

ozone while VOC reductions have little effect. Such conditions are called “NOx limited.” 

Because the contribution of VOC emissions from biogenic (natural) sources to local ambient

ozone concentrations can be significant, even some areas where man-made VOC emissions are

relatively low can be NOx limited.

When NOx levels are relatively high and VOC levels relatively low, NOx forms inorganic

nitrates but relatively little ozone. Such conditions are called “VOC limited.” Under these

conditions, VOC reductions are effective in reducing ozone, but NOx reductions can actually

increase local ozone under certain circumstances. Even in VOC limited urban areas, NOx

reductions are not expected to increase ozone levels if the NOx reductions are sufficiently large. 
Final Regulatory Support Document

2-14

Rural areas are almost always NOx limited, due to the relatively large amounts of biogenic

VOC emissions in such areas. Urban areas can be either VOC or NOx limited, or a mixture of

both.

Ozone concentrations in an area also can be lowered by the reaction of nitric oxide with

ozone, forming nitrogen dioxide (NO2); as the air moves downwind and the cycle continues, the

NO2 forms additional ozone. The importance of this reaction depends, in part, on the relative

concentrations of NOx, VOC, and ozone, all of which change with time and location. 

As described in Section 2.1, Category 3 engines currently account for about 1.6 and 0.1

percent of the national mobile source NOx and HC inventories, respectively. This is expected to

increase to 8.9 and 0.5 percent, respectively, by 2030 even when considering the presence of the

internationally negotiated NOx limits.

 

2.2.2 Health and Welfare Effects of Ozone and Its Precursors

Based on a large number of studies, EPA has identified several key health effects caused

when people are exposed to levels of ozone found today in many areas of the country.8, 9 Shortterm exposures (1 to 3 hours) to high ambient ozone concentrations have been linked to

increased hospital admissions and emergency room visits for respiratory problems. For example,

studies conducted in the northeastern U.S. and Canada show that ozone air pollution is associated

with 10-20 percent of all of the summertime respiratory-related hospital admissions. Repeated

exposure to ozone can make people more susceptible to respiratory infection and lung

inflammation and can aggravate preexisting respiratory diseases, such as asthma. Prolonged (6

to 8 hours), repeated exposure to ozone can cause inflammation of the lung, impairment of lung

defense mechanisms, and possibly irreversible changes in lung structure, which over time could

lead to premature aging of the lungs and/or chronic respiratory illnesses such as emphysema and

chronic bronchitis. 

Children and outdoor workers are most at risk from ozone exposure because they typically

are active outside during the summer when ozone levels are highest. For example, summer camp

studies in the eastern U.S. and southeastern Canada have reported significant reductions in lung

function in children who are active outdoors. Further, children are more at risk than adults from

ozone exposure because their respiratory systems are still developing. Adults who are outdoors

and are moderately active during the summer months, such as construction workers and other

outdoor workers, also are among those most at risk. These individuals, as well as people with

respiratory illnesses such as asthma, especially asthmatic children, can experience reduced lung

function and increased respiratory symptoms, such as chest pain and cough, when exposed to

relatively low ozone levels during prolonged periods of moderate exertion. 

Ozone can aggravate asthma and can cause coughs and chest pain, lung inflammation and

cell damage, decreases in lung function, and increased susceptibility to respiratory infection.

Ozone has been associated with increased hospitalizations and emergency room visits for

respiratory causes. Repeated exposure over time may permanently damage lung tissue.
Chapter 2: Health and Welfare Concerns

2-15

The 8-hour standard, issued by EPA in 1997, is based on well-documented science

demonstrating that more people are experiencing adverse health effects at lower levels of

exertion, over longer periods, and at lower ozone concentrations than addressed by the one-hour

ozone standard. The 8-hour standard greatly limits ozone exposures of concern for the general

population and populations most at risk, including children active outdoors, outdoor workers, and

individuals with pre-existing respiratory disease, such as asthma.

Since the ozone national ambient air quality standards (NAAQS) were promulgated in 1997,

over fifteen hundred new health and welfare studies have been published. Many of these studies

have investigated the impact of ozone exposure on such health effects as changes in lung

structure and biochemistry, inflammation of the lungs, exacerbation and causation of asthma,

respiratory illness-related school absence, hospital and emergency room visits for asthma and

other respiratory causes, and premature mortality. Although these studies have been published in

peer reviewed journals, they have not yet been incorporated into a revised Air Quality Criteria

Document for Ozone and Other Photochemical Oxidants. Key new health information falls into

four general areas: development of new-onset asthma, hospital admissions for young children,

school absence rate, and premature mortality. 

Aggravation of existing asthma resulting from ambient ozone exposure was reported prior to

the 1997 decision and has been observed in studies published since (Thurston et al., 1997; Ostro

et al., 2001). Although preliminary, an important new finding is evidence suggesting that air

pollution and outdoor exercise could contribute to the development of new-onset asthma. In

particular, a relationship between long-term ambient ozone concentrations and the incidence of

asthma in adults was reported by McDonnell et al. (1999). Subsequently, McConnell et al.

(2002) suggested that incidence of new diagnoses of asthma in children is associated with heavy

exercise in communities with high concentrations of ozone.

Previous studies have shown relationships between ozone and hospital admissions in the

general population. A new study in Toronto found a significant relationship between 1-hour

maximum ozone concentrations and respiratory hospital admissions in children under two

(Burnett et al. 2001). Given the relative vulnerability of children in this age category, this is an

important addition to the literature on ozone and hospital admissions.

Increased school absence rate caused by respiratory illness has been associated with 1-hour

daily maximum and 8-hour average ozone concentrations in studies conducted in Nevada (Chen

et al., 2000) in grades K-6 and in Southern California (Gilliland et al., 2001) in grades 4-6. 

These studies suggest that higher ambient ozone levels may result in increased school

absenteeism.

The air pollutant most clearly associated with premature mortality is particulate matter, with

dozens of studies reporting such an association. Repeated ozone exposure is a likely contributing

factor for premature mortality, causing an inflammatory response in the lungs which may

predispose elderly and other sensitive individuals to become more susceptible. The findings of

three recent analyses provide consistent data suggesting that ozone exposure is associated with
Final Regulatory Support Document

2-16

increased mortality. Although the National Morbidity, Mortality, and Air Pollution Study did not

find an effect of ozone on total mortality across the full year, Samet et al. (2000), who conducted

the study, did observe an effect after limiting the analysis to summer when ozone levels are

highest. Similarly, Thurston and Ito (1999) have shown associations between ozone and

mortality. Toulomi et al. (1997) found that 1-hour maximum ozone levels were associated with

daily numbers of deaths in 4 cities (London, Athens, Barcelona, and Paris), and a quantitatively

similar effect was found in a group of 4 additional cities (Amsterdam, Basel, Geneva, and

Zurich). 

In addition to the health effects described above, there exists a large body of scientific

literature that shows that harmful effects can occur from sustained levels of ozone exposure at

low levels. Studies of prolonged exposures, those lasting about 7 hours, showed health effects

from exposures to ozone concentrations as low as 0.08 ppm. Prolonged and repeated exposures

to ozone at these levels are common in areas that do not attain the 1-hour NAAQS, and also

occur in areas where ambient concentrations of ozone are in compliance with the 1-hour

NAAQS. 

Prolonged exposure to levels of ozone below the NAAQS have been reported to cause or be

statistically associated with transient pulmonary function responses, transient respiratory

symptoms, effects on exercise performance, increased airway responsiveness, increased

susceptibility to respiratory infection, increased hospital and emergency room visits, and transient

pulmonary respiratory inflamation. Such acute health effects have been observed following

prolonged exposures at moderate levels of exertion at concentrations of ozone as low as 0.08

ppm, the lowest concentration tested. The effects are more pronounced as concentrations

increase, affecting more subjects or having a greater effect on a given subject in terms of

functional changes or symptoms. A detailed summary and discussion of the large body of ozone

health effects research may be found in Chapters 6 through 9 (Volume 3) of the 1996 Criteria

Document for ozone.10 Monitoring data indicates that 291 counties have design values that

exceed these levels based on 1999-2001 data in 1997-99.11

Ozone can have other welfare effects, with damage to plants and ecosystems being of most

concern. Ozone adversely affects crop yield, vegetation and forest growth, and the durability of

materials. Because ground-level ozone interferes with the ability of a plant to produce and store

food, plants become more susceptible to disease, insect attack, harsh weather and other

environmental stresses. Ozone causes noticeable foliage damage in many crops, trees, and

ornamental plants (i.e., grass, flowers, shrubs) and causes reduced growth in plants. Studies

indicate that current ambient levels of ozone are responsible for damage to forests and

ecosystems (including habitat for native animal species). The adverse effect of ozone on forests

and other natural vegetation can in turn cause damage to associated ecosystems, with additional

resulting economic losses. Prolonged ozone concentrations of 0.10 ppm can be phytotoxic to a

large number of plant species, and can produce acute injury and reduced crop yield and biomass

production. Ozone concentrations within the range of 0.05 to 0.10 ppm have the potential over a

longer duration of creating chronic stress on vegetation that can result in reduced plant growth

and yield, shifts in competitive advantages in mixed populations, decreased vigor, and injury. 
Chapter 2: Health and Welfare Concerns

2-17

Ozone effects on vegetation are discussed in Section 2.2.4 below and presented in more detail in

Chapter 5, Volume II of the 1996 Criteria Document. In addition, ozone chemically attacks

elastomers (natural rubber and certain synthetic polymers), textile fibers and dyes, and, to a lesser

extent, paints. For example, elastomers become brittle and crack, and dyes fade after exposure to

ozone. 

2.2.3 Ozone Nonattainment and Contribution to Ozone Nonattainment

The current primary and secondary ozone National Ambient Air Quality Standard (NAAQS)

is 0.12 ppm daily maximum 1-hour concentration, not to be exceeded more than once per year on

average. The determination that an area is at risk of exceeding the ozone standard in the future

was made for all areas with current design values greater than or equal to 0.125 ppm (or within a

10 percent margin) and with modeling evidence that exceedances will persist into the future. 

EPA is replacing the previous 1-hour ozone standard with a new 8-hour standard. The new

standard is set at a concentration of 0.08 parts per million (ppm). The measurement period is 8

hours. Areas are allowed to disregard their three worst measurements every year and average

performance over three years to determine if they meet the standard. That is, the standard is set

by the 4th highest maximum 8-hour concentration. 

Ground level ozone today remains a pervasive pollution problem in the United States. About

51 million people live in areas with design values above the level of the 1-hour ozone standard

based on three years of data (1999-2001). In addition, about 111 million people live in areas

with design values above the 8-hour ozone standard based on those three years of data. 

Approximately 61 million of these people live in areas with design values above the 8-hour

standard but are below the design standard for the 1-hour ozone standard (i.e., they are attaining

the 1-hour standard). The remainder of these people live in areas with design values above the 8-

hour ozone standards but are above the design value for the 1-hour ozone standard (i.e., they are

not attaining the 1-hour standard).12 This represents 222 counties with design values above the

level of the 8-hour standard.

Over the last decade, declines in ozone levels were found mostly in urban areas, where

emissions are heavily influenced by controls on mobile sources and their fuels. Twenty-three

metropolitan areas have realized a decline in ozone levels since 1989, but at the same time ozone

levels in 11 metropolitan areas with 7 million people have increased.13 Regionally, California

and the Northeast have recorded significant reductions in peak ozone levels, while four other

regions (the Mid-Atlantic, the Southeast, the Central and Pacific Northwest) have seen ozone

levels increase. The highest ambient concentrations are currently found in suburban areas,

consistent with downwind transport of emissions from urban centers. Concentrations in rural

areas have risen to the levels previously found only in cities.
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2.2.4 Additional Health and Welfare Effects of NOx Emissions

In addition to their role as an ozone precursor, NOx emissions are associated with a wide

variety of other health and welfare effects.14, 15 Nitrogen dioxide can irritate the lungs and reduce

resistance to respiratory infection (such as influenza). Nitrogen dioxide and airborne nitrate also

contribute to pollutant haze, which impairs visibility and can reduce residential property values

and the value placed on scenic views. Elevated levels of nitrates in drinking water pose

significant health risks, especially to infants. NOx emissions are an important precursor to acid

rain that may affect both terrestrial and aquatic ecosystems. Atmospheric deposition of nitrogen

leads to excess nutrient enrichment problems (“eutrophication”). Deposition of nitrogencontaining compounds also affects terrestrial ecosystems.

2.2.4.1 Acid Deposition

Acid deposition, or acid rain as it is commonly known, occurs when SO2 and NOx react in

the atmosphere with water, oxygen, and oxidants to form various acidic compounds that later fall

to earth in the form of precipitation or dry deposition of acidic particles.16 It contributes to

damage of trees at high elevations and in extreme cases may cause lakes and streams to become

so acidic that they cannot support aquatic life. In addition, acid deposition accelerates the decay

of building materials and paints, including irreplaceable buildings, statues, and sculptures that are

part of our nation's cultural heritage. To reduce damage to automotive paint caused by acid rain

and acidic dry deposition, some manufacturers use acid-resistant paints, at an average cost of $5

per vehicle--a total of $61 million per year if applied to all new cars and trucks sold in the U.S. 

Acid deposition primarily affects bodies of water that rest atop soil with a limited ability to

neutralize acidic compounds. The National Surface Water Survey investigated the effects of

acidic deposition in over 1,000 lakes larger than 10 acres and in thousands of miles of streams. It

found that acid deposition was the primary cause of acidity in 75 percent of the acidic lakes and

about 50 percent of the acidic streams, and that the areas most sensitive to acid rain were the

Adirondacks, the mid-Appalachian highlands, the upper Midwest and the high elevation West. 

The National Surface Water Survey found that approximately 580 streams in the Mid-Atlantic

Coastal Plain are acidic primarily due to acidic deposition. Hundreds of the lakes in the

Adirondacks surveyed have acidity levels incompatible with the survival of sensitive fish species. 

Many of the over 1,350 acidic streams in the Mid-Atlantic Highlands (mid-Appalachia) region

have already experienced trout losses due to increased stream acidity. Emissions from U.S.

sources contribute to acidic deposition in eastern Canada, where the Canadian government has

estimated that 14,000 lakes are acidic. Acid deposition also has been implicated in contributing

to degradation of high-elevation spruce forests that populate the ridges of the Appalachian

Mountains from Maine to Georgia.

2.2.4.2 Eutrophication and Nitrification

Nitrogen deposition into bodies of water can cause problems beyond those associated with

acid rain. The Ecological Society of America has included discussion of the contribution of air
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emissions to increasing nitrogen levels in surface waters in a recent major review of causes and

consequences of human alteration of the global nitrogen cycle in its Issues in Ecology series.17

Long-term monitoring in the United States, Europe, and other developed regions of the world

shows a substantial rise of nitrogen levels in surface waters, which are highly correlated with

human-generated inputs of nitrogen to their watersheds. These nitrogen inputs are dominated by

fertilizers and atmospheric deposition.

Human activity can increase the flow of nutrients into those waters and result in excess algae

and plant growth. This increased growth can cause numerous adverse ecological effects and

economic impacts, including nuisance algal blooms, dieback of underwater plants due to reduced

light penetration, and toxic plankton blooms. Algal and plankton blooms can also reduce the

level of dissolved oxygen, which can also adversely affect fish and shellfish populations. This

problem is of particular concern in coastal areas with poor or stratified circulation patterns, such

as the Chesapeake Bay, Long Island Sound, or the Gulf of Mexico. In such areas, the

"overproduced" algae tends to sink to the bottom and decay, using all or most of the available

oxygen and thereby reducing or eliminating populations of bottom-feeder fish and shellfish,

distorting the normal population balance between different aquatic organisms, and in extreme

cases causing dramatic fish kills.

Collectively, these effects are referred to as eutrophication, which the National Research

Council recently identified as the most serious pollution problem facing the estuarine waters of

the United States.18 Nitrogen is the primary cause of eutrophication in most coastal waters and

estuaries.19 On the New England coast, for example, the number of red and brown tides and

shellfish problems from nuisance and toxic plankton blooms have increased over the past two

decades, a development thought to be linked to increased nitrogen loadings in coastal waters. 

We believe that airborne NOx contributes from 12 to 44 percent of the total nitrogen loadings to

United States coastal water bodies. For example, some estimates assert that approximately onequarter of the nitrogen in the Chesapeake Bay comes from atmospheric deposition. 

Excessive fertilization with nitrogen-containing compounds can also affect terrestrial

ecosystems.20 Research suggests that nitrogen fertilization can alter growth patterns and change

the balance of species in an ecosystem, providing beneficial nutrients to plant growth in areas

that do not suffer from nitrogen over-saturation. In extreme cases, this process can result in

nitrogen saturation when additions of nitrogen to soil over time exceed the capacity of the plants

and microorganisms to utilize and retain the nitrogen. This phenomenon has already occurred in

some areas of the U.S. 

2.3 Particulate Matter

2.3.1 General Background

Particulate pollution is a problem affecting urban and non-urban localities in all regions of

the United States. Particulate matter (PM) represents a broad class of chemically and physically

diverse substances. It can be principally characterized as discrete particles that exist in the
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condensed (liquid or solid) phase spanning several orders of magnitude in size. All particles

equal to and less than 10 microns are called PM10. Fine particles can be generally defined as

those particles with an aerodynamic diameter of 2.5 microns or less (also known as PM2.5), and

coarse fraction particles are those particles with an aerodynamic diameter greater than 2.5

microns, but equal to or less than a nominal 10 microns.

Manmade emissions that contribute to airborne particulate matter result principally from

combustion sources (stationary and mobile sources) and fugitive emissions from industrial

processes and non-industrial processes (such as roadway dust from paved and unpaved roads,

wind erosion from crop land, construction, etc.). Human-generated sources of particles include a

variety of stationary sources (including power generating plants, industrial operations,

manufacturing plants, waste disposal) and mobile sources (light- and heavy-duty on-road

vehicles, and off-highway vehicles such as construction, farming, industrial, locomotives, marine

vessels and other sources). Natural sources also contribute to particulate matter in the

atmosphere and include sources such as wind erosion of geological material, sea spray, volcanic

emissions, biogenic emanation (e.g., pollen from plants, fungal spores), and wild fires.

The chemical and physical properties of PM vary greatly with time, region, meteorology, and

source category. Particles may be emitted directly to the atmosphere (primary particles) or may

be formed by transformations of gaseous emissions of sulfur dioxide, oxides of nitrogen or

volatile organic compounds (secondary particles). The vast majority (>90 percent) of the direct

mobile-source PM emissions and their secondary formation products are in the fine PM size

range. Mobile sources can reasonably be estimated to contribute to ambient secondary nitrate

and sulfate PM in proportion to their contribution to total NOx and SOx emissions.

As described in Section 2.1, Category 3 engines currently account for about 2.8 percent of the

national mobile source PM inventory; this is expected to increase to 7.3 percent by 2030 if left

uncontrolled.

2.3.2 Health and Welfare Effects of PM

Particulate matter can adversely affect human health and welfare. Discussions of the health

and welfare effects associated with ambient PM can be found in the Air Quality Criteria for

Particulate Matter.21

Key EPA findings regarding the health risks posed by ambient PM are summarized as

follows:

a. Health risks posed by inhaled particles are affected both by the penetration and deposition of

particles in the various regions of the respiratory tract, and by the biological responses to

these deposited materials.

b. The risks of adverse effects associated with deposition of ambient particles in the thorax

(tracheobronchial and alveolar regions of the respiratory tract) are markedly greater than for
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deposition in the extrathoracic (head) region. Maximum particle penetration to the thoracic

regions occurs during oronasal or mouth breathing.

c. Published peer-reviewed studies have reported statistical associations between PM and

several key health effects, including premature death; aggravation of respiratory and

cardiovascular disease, as indicated by increased hospital admissions and emergency room

visits, school absences, work loss days, and restricted activity days; changes in lung function

and increased respiratory symptoms; changes to lung tissues and structure; and altered

respiratory defense mechanisms. Most of these effects have been consistently associated with

ambient PM concentrations, which have been used as a measure of population exposure, in a

large number of community epidemiological studies. Additional information and insights on

these effects are provided by studies of animal toxicology and controlled human exposures to

various constituents of PM conducted at higher than ambient concentrations. Although

mechanisms by which particles cause effects are not well known, there is general agreement

that the cardio-respiratory system is the major target of PM effects.

d. Based on a qualitative assessment of the epidemiological evidence of effects associated with

PM for populations that appear to be at greatest risk with respect to particular health

endpoints, we have concluded the following with respect to sensitive populations:

1. Individuals with respiratory disease (e.g., chronic obstructive pulmonary disease, acute

bronchitis) and cardiovascular disease (e.g., ischemic heart disease) are at greater risk of

premature mortality and hospitalization due to exposure to ambient PM.

2. Individuals with infectious respiratory disease (e.g., pneumonia) are at greater risk of

premature mortality and morbidity (e.g., hospitalization, aggravation of respiratory

symptoms) due to exposure to ambient PM. Also, exposure to PM may increase

individuals’ susceptibility to respiratory infections.

3. Elderly individuals are also at greater risk of premature mortality and hospitalization for

cardiopulmonary problems due to exposure to ambient PM.

4. Children are at greater risk of increased respiratory symptoms and decreased lung

function due to exposure to ambient PM.

5. Asthmatic individuals are at risk of exacerbation of symptoms associated with asthma,

and increased need for medical attention, due to exposure to PM.

e. There are fundamental physical and chemical differences between fine and coarse fraction

particles. The fine fraction contains acid aerosols, sulfates, nitrates, transition metals, diesel

exhaust particles, and ultra fine particles; the coarse fraction typically contains high mineral

concentrations, silica and resuspended dust. It is reasonable to expect that differences may

exist in both the nature of potential effects elicited by coarse and fine PM and the relative

concentrations required to produce such effects. Both fine and coarse particles can
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2-22

accumulate in the respiratory system. Exposure to coarse fraction particles is primarily

associated with the aggravation of respiratory conditions such as asthma. Fine particles are

closely associated with health effects such as premature death or hospital admissions, and for

cardiopulmonary diseases.

With respect to welfare or secondary effects, fine particles have been clearly associated with

the impairment of visibility over urban areas and large multi-State regions. Particles also

contribute to soiling and materials damage. Components of particulate matter (e.g., sulfuric

or nitric acid) also contribute to acid deposition, nitrification of surface soils and water

eutrophication of surface water.

2.3.3 PM Nonattainment

There are two indicators related to PM NAAQS. The first indicator is PM10, and the second

is PM2.5. Concentrations above the PM2.5 standard are much more widespread than are violations

of the PM10 standard, and emission reductions needed to attain the PM2.5 standards will also lead

to attainment of the PM10 standards. 

2.3.3.1 PM10 Concentrations and Nonattainment

The NAAQS for PM10 was established in 1987. According to these standards, the short term

(24-hour) standard of 150 μg/m3

 is not to be exceeded more than once per year on average over

three years. The long-term standard specifies an expected annual arithmetic mean not to exceed

50 μg/m3 over three years. Recent PM10 monitoring data indicates that there are 8 serious and 58

moderate PM10 nonattainment areas with about 30 million people in 63 mainly western counties.

2.3.3.2 PM2.5 Concentrations

The NAAQS for PM2.5 indicator was established in 1997. According to these standards, the

short term (24-hour) standard is set at 65 μg/m3

 based on the 98th percentile averaged over three

years. The long-term standard specifies an expected annual arithmetic mean not to exceed 15

μg/m3

 over three years. 

Fine particle concentrations contribute to both health effects and visibility impairment. We

have monitored air quality data that establishes a present widespread nonattainment problem, and

modeling results that indicate a continuing problem plus visibility needs. Current PM2.5

monitored values for 1999-2001, which cover about a quarter of the nation’s counties, indicate

that at least 65 million people in 129 counties live in areas where design values of ambient fine

particulate matter levels are at or above the PM2.5 NAAQS. Three years of complete data are

required to make regulatory determinations of attainment or nonattainment but, based on more

limited available data, there are an additional 9 million people in 20 counties where levels

exceeding the NAAQS are being measured, but there are insufficient data at this time to make an

official estimate of the design value. In total, this represents 39 percent of the population in the

areas with monitors.22 To estimate the current number of people who live in areas where long-
Chapter 2: Health and Welfare Concerns

2-23

term ambient fine particulate matter levels are at or above 16 μg/m3 but for which there are no

monitors, we can use modeling performed for the Heavy-Duty Engine and Vehicle Standards and

Highway Diesel Fuel Sulfur Control rule (also called the “HD07" rule) described elsewhere.23 At

that time, we conducted 1996 base year modeling to reproduce the atmospheric processes

resulting in formation and dispersion of PM2.5 across the U.S. This 1996 modeling included

emissions subject to this final rule. According to our national model predictions, there were a

total of 76 million people (1996 population) living in areas with modeled annual average PM2.5

concentrations at or above 16 μg/m3 (29 percent of the population).24

While the final implementation process for bringing the Nation’s air into attainment with the

PM2.5 NAAQS is still being completed, the basic framework is well defined. EPA’s current plans

call for designating PM2.5 nonattainment areas in late-2004. Following designation, Section

172(b) of the Clean Air Act allows states up to three years to submit a revision to their state

implementation plan (SIP) that provides for the attainment of the PM2.5 standards. We expect

states to submit these SIPs in late-2007. Section 172(a)(2) of the Clean Air Act requires that

these SIP revisions demonstrate that the nonattainment areas will attain the PM2.5 standards as

expeditiously as practicable but no later than five years from the date that the area was designated

nonattainment. However, based on the severity of the air quality problem and the availability and

feasibility of control measures, the Administrator may extend the attainment date “for a period of

no greater than 10 years from the date of designation as nonattainment.” Therefore, we expect

that areas will be ultimately be required to attain the PM2.5 air quality standard in the 2009 to

2014 time frame.

2.3.4 Diesel Exhaust

In addition to its contribution to ambient PM inventories, diesel exhaust PM is of special

concern because it has been implicated in an increased risk of lung cancer and respiratory disease

in human studies, and an increased risk of noncancer health effects as well. 

EPA recently released its final “Health Assessment Document for Diesel Engine Exhaust”

(the Diesel HAD).25 There, we concluded that diesel exhaust is likely to be carcinogenic to

humans by inhalation and environmental exposures in accordance with the revised draft

1996/1999 EPA cancer guidelines. A number of other agencies (e.g., National Institute for

Occupational Safety and Health, the International Agency for Research on Cancer, the World

Health Organization, California EPA, and the US Department of Health and Human Services)

have made similar determinations.

The EPA Diesel HAD states that the conclusions of the document apply to diesel exhaust as a

whole including both on-road and non-road engines as well as older and newer engines.

EPA generally derives cancer unit risk estimates to more precisely estimate risk from

exposure to carcinogens. The cancer unit risk is that increased risk associated with average

lifetime exposure of 1 μg/m3

. EPA concluded in the Diesel HAD that it is not possible to

currently calculate a cancer unit risk for diesel particles due to a variety of factors that limit the
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2-24

current studies such as lack of adequate dose-response relations between exposure versus cancer

incidence. However, in the absence of a cancer unit risk, the Diesel HAD made estimates about

the possible magnitude of risk from exposure to diesel exhaust by comparing the environmental

exposure levels to the occupational exposure levels. This analysis suggests a range for

environmental risk between 10-3 and 10-5. While these risk estimates are exploratory and not

intended to provide a definitive characterization of cancer risk, they are useful in gauging the

possible range of risk based on reasonable judgement. It is important to note that the possible

risks could also be lower and a zero risk cannot be ruled out. Some individuals in the population

may have a high tolerance to exposure from diesel exhaust and low cancer susceptibility. Also,

there could be a threshold of exposure below which there is no cancer risk although evidence has

not been seen or substantiated on this point.

Even though EPA does not have a carcinogenic potency with which to accurately estimate the

carcinogenic impact of diesel exhaust, the likely hazard to humans together with the potential for

significant environmental risks leads us to conclude that diesel exhaust emissions should be

reduced from nonroad engines in order to protect public health. The following factors lead to our

determination:

• EPA has officially designated diesel exhaust has been designed a likely human

carcinogen. Other organizations have made similar determinations.

• The entire population is exposed to various levels of diesel exhaust.

• The possible range of risk for the general US population due to exposure to diesel exhaust

is 10-3 to 10-5 although the risk could be lower and a zero risk cannot be ruled out.

Thus, the concern for a carcinogenicity hazard resulting from diesel exhaust exposures is

longstanding and widespread.

2.4 Carbon Monoxide

2.4.1 General Background

Unlike many gases, CO is odorless, colorless, tasteless, and nonirritating. Carbon monoxide

results from incomplete combustion of fuel and is emitted directly from vehicle tailpipes. 

Incomplete combustion is most likely to occur at low air-to-fuel ratios in the engine. These

conditions are common during vehicle starting when air supply is restricted (“choked”), when

vehicles are not tuned properly, and at high altitude, where “thin” air effectively reduces the

amount of oxygen available for combustion (except in engines that are designed or adjusted to

compensate for altitude). Carbon monoxide emissions increase dramatically in cold weather. 

This is because engines need more fuel to start at cold temperatures and because some emission

control devices (such as oxygen sensors and catalytic converters) operate less efficiently when

they are cold. Also, nighttime inversion conditions are more frequent in the colder months of the

year. This is due to the enhanced stability in the atmospheric boundary layer, which inhibits

vertical mixing of emissions from the surface.
Chapter 2: Health and Welfare Concerns

2-25

As described in Section 2.1, Category 3 engines currently account for about 0.02 percent of

the national mobile source CO inventory; this is expected to increase to 0.05 percent by 2030 if

left uncontrolled.

2.4.2 Health Effects of CO

Carbon monoxide enters the bloodstream through the lungs and forms carboxyhemoglobin

(COHb), a compound that inhibits the blood’s capacity to carry oxygen to organs and tissues.26

Carbon monoxide has long been known to have substantial adverse effects on human health,

including toxic effects on blood and tissues, and effects on organ functions. Although there are

effective compensatory increases in blood flow to the brain, at some concentrations of COHb,

somewhere above 20 percent, these compensations fail to maintain sufficient oxygen delivery,

and metabolism declines.27 The subsequent hypoxia in brain tissue then produces behavioral

effects, including decrements in continuous performance and reaction time.28

Carbon monoxide has been linked to increased risk for people with heart disease, reduced

visual perception, cognitive functions and aerobic capacity, and possible fetal effects. Persons

with heart disease are especially sensitive to carbon monoxide poisoning and may experience

chest pain if they breathe the gas while exercising. Infants, elderly persons, and individuals with

respiratory diseases are also particularly sensitive. Carbon monoxide can affect healthy

individuals, impairing exercise capacity, visual perception, manual dexterity, learning functions,

and ability to perform complex tasks.

Several recent epidemiological studies have shown a link between CO and premature

morbidity (including angina, congestive heart failure, and other cardiovascular diseases. Several

studies in the United States and Canada have also reported an association of ambient CO

exposures with frequency of cardiovascular hospital admissions, especially for congestive heart

failure (CHF). An association of ambient CO exposure with mortality has also been reported in

epidemiological studies, though not as consistently or specifically as with CHF admissions. EPA

reviewed these studies as part of the Criteria Document review process.29 There is emerging

evidence suggesting that CO is linked with asthma exacerbations.

2.4.3 CO Nonattainment

The current primary NAAQS for CO are 35 parts per million for the one-hour average and 9

parts per million for the eight-hour average. These values are not to be exceeded more than once

per year. Air quality carbon monoxide value is estimated using EPA guidance for calculating

design values. In 1999, 30.5 million people (1990 census) lived in 17 areas designated

nonattainment under the CO NAAQS.30 

Nationally, significant progress has been made over the last decade to reduce CO emissions

and ambient CO concentrations. Total CO emissions from all sources have decreased 16 percent

from 1989 to 1998, and ambient CO concentrations decreased by 39 percent. During that time,

while the mobile source CO contribution of the inventory remained steady at about 77 percent,
Final Regulatory Support Document

b

Visual range can be defined as the maximum distance at which one can identify a black

object against the horizon sky. It is typically described in miles or kilometers. Light extinction is

the sum of light scattering and absorption by particles and gases in the atmosphere. It is typically

expressed in terms of inverse megameters (Mm-1), with larger values representing worse

visibility. The deciview metric describes perceived visual changes in a linear fashion over its

entire range, analogous to the decibel scale for sound. A deciview of 0 represents pristine

conditions. Under many scenic conditions, a change of 1 deciview is considered perceptible by

the average person.

2-26

the highway portion decreased from 62 percent of total CO emissions to 56 percent while the

nonroad portion increased from 17 percent to 22 percent.31 Over the next decade, we would

expect there to be a minor decreasing trend from the highway segment due primarily to the more

stringent standards for certain light-duty trucks.32 CO standards for passenger cars and other

light-duty trucks and heavy-duty vehicles did not change as a result of other recent rulemakings.

2.5 Visibility Degradation

2.5.1 General Background

Visibility can be defined as the degree to which the atmosphere is transparent to visible

light.33 Visibility impairment has been considered the “best understood and most easily

measured effect of air pollution.”34 Visibility degradation is often directly proportional to

decreases in light transmittal in the atmosphere. Scattering and absorption by both gases and

particles decrease light transmittance. It is an easily noticeable effect of fine PM present in the

atmosphere, and fine PM is the major cause of reduced visibility in parts of the United States,

including many of our national parks and in places where people live, work, and recreate. Fine

particles with significant light-extinction efficiencies include organic matter, sulfates, nitrates,

elemental carbon (soot), and soil. The engines subject to this rule contribute to visibility

degradation through their contribution to the national PM inventory.

Visibility is an important effect 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, both where they live and work and in places where they enjoy

recreational opportunities. Visibility is highly valued in significant natural areas such as national

parks and wilderness areas because of the special emphasis given to protecting these lands now

and for future generations. Visibility can be described in terms of visual range, light extinction

or deciview.b

In addition to limiting the distance that one can see, the scattering and absorption of light

caused by air pollution can also degrade the color, clarity, and contrast of scenes. Visibility

impairment also has a temporal dimension in that impairment might relate to a short-term

excursion or to longer periods (e.g., worst 20 percent of days or annual average levels). More

detailed discussions of visibility effects are contained in the EPA Criteria Document for PM.
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2-27

Visibility effects are manifest in two principal ways: (1) as local impairment (e.g., localized

hazes and plumes) and (2) as regional haze. The emissions from engines covered by this rule

contribute to both types of visibility impairment. 

Local-scale visibility degradation is commonly in the form of either a plume resulting from

the emissions of a specific source or small group of sources, or it is in the form of a localized

haze such as an urban “brown cloud.” Plumes are comprised of smoke, dust, or colored gas that

obscure the sky or horizon relatively near sources. Impairment caused by a specific source or

small group of sources has been generally termed as “reasonably attributable.”

The second type of impairment, regional haze, results from pollutant emissions from a

multitude of sources located across a broad geographic region. It impairs visibility in every

direction over a large area, in some cases over multi-state regions. Regional haze masks objects

on the horizon and reduces the contrast of nearby objects. The formation, extent, and intensity of

regional haze is a function of meteorological and chemical processes, which sometimes cause

fine particulate loadings to remain suspended in the atmosphere for several days and to be

transported hundreds of kilometers from their sources.35

On an annual average basis, the concentrations of non-anthropogenic fine PM are generally

small when compared with concentrations of fine particles from anthropogenic sources.36

Anthropogenic contributions account for about one-third of the average extinction coefficient in

the rural West and more than 80 percent in the rural East.37 Because of significant differences

related to visibility conditions in the eastern and western U.S., we present information about

visibility by region. Furthermore, it is important to note that even in those areas with relatively

low concentrations of anthropogenic fine particles, such as the Colorado plateau, small increases

in anthropogenic fine particle concentrations can lead to significant decreases in visual range. 

This is one of the reasons Class I areas have been given special consideration under the Clean Air

Act.

2.5.2 Visibility Impairment Where People Live, Work and Recreate

Visibility impairment occurs in many areas throughout the country, where people live, work,

and recreate, including Class I Areas. As described in Section 2.12 above, the engines covered

by this rule contribute to PM2.5 levels in areas across the country with unacceptable visibility

conditions.

The secondary PM NAAQS is designed to protect against adverse welfare effects such as

visibility impairment. In 1997, the secondary PM NAAQS was set as equal to the primary

(health-based) PM NAAQS (62 Federal Register No. 138, July 18, 1997). EPA concluded that

PM can and does produce adverse effects on visibility in various locations, depending on PM

concentrations and factors such as chemical composition and average relative humidity. In 1997,

EPA demonstrated that visibility impairment is an important effect on public welfare and that

visibility impairment is experienced throughout the U.S., in multi-state regions, urban areas, and

remote Federal Class I areas. 
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EPA recently finalized a finding that nonroad engines contribute significantly to adverse

visibility effects (67 FR 68251, November 8, 2002). Category 3 engines contribute to these

effects. They are estimated to emit 54 tons of direct PM in 2030, which is 7.3 percent of total

mobile source anthropogenic PM emissions. They also contribute to visibility degradation

through their NOx and HC emissions.
Chapter 2: Health and Welfare Concerns

2-29

1.“Commercial Marine Emission Inventory Development.” E. H. Pechan and Associates, Inc.

and ENVIRON International Corporation. April 2002. Air Docket A-2001-11, item II-A-67.

2.Memorandum to Docket A-2001-11 from Jean Marie Revelt, “Santa Barbara County Air

Quality News, Issue 62, July-August 2001 and other materials provided to EPA by Santa Barbara

County,” March 14, 2002. Air Docket A-2001-11, Document No. II-A-47.

3.”Houston-Galveston Area Vessel Emissions Inventory.” Prepared by Starcrest Consulting

Group, LLC for the Port of Houston Authority. November 2000. Air Docket A-2001-11,

Document No. IV-A-17.

4.”Marine Vessels Emissions Inventory - Update to 1996 Report: Marine Vessel Emissions

Inventory and Control Strategies, Final Report.” Prepared by Arcadis, Geraghty & Miller for the

South Coast Air Quality Management District. September 23, 1999. Air Docket A-2001-11,

Document No. IV-A-18.

5.Letter from Bruce J. Carlton, Acting Deputy Maritime Administrator, U.S. Department of

Transportation, Maritime Administration to Jeffrey R. Holmstead, U.S. EPA, August 29, 2002. 

Air Docket A-2001-11, item IV-G-04.

6. “Final Regulatory Impact Analysis: Control of Emissions from Marine Diesel Engines,” U.S.

EPA, November 1999.

7.Carbon monoxide also participates in the production of ozone, albeit at a much slower rate than

most VOC and NOx compounds.

8.U.S. EPA, 1996, Review of National Ambient Air Quality Standards for Ozone, Assessment of

Scientific and Technical Information, OAQPS Staff Paper, EPA452-R-96-007. A copy of this

document can be obtained from Air Docket A-99-06, Document No. II-A-22.

9.U.S. EPA, 1996, Air Quality Criteria for Ozone and Related Photochemical Oxidants,

EPA/600/P-93/004aF. The document is available on the internet at

http://www.epa.gov/ncea/ozone.htm. A copy can also be obtained from Air Docket No. A-99-

06, Document Nos. II-A-15, II-A-16, II-A-17.

10.Air Quality Criteria Document for Ozone and Related Photochemical Oxidants, EPA National

Center for Environmental Assessment, July 1996, Report No. EPA/600/P-93/004cF. The

document is available on the internet at http://www.epa.gov/ncea/ozone.htm. A copy can also be

obtained from Air Docket No. A-99-06, Documents Nos. II-A-15, II-A-16, II-A-17.

11.Memorandum to Docket A-2001-11 from Fred Dimmick, Group Leader, Air Trends Group,

“Summary of Currently Available Air Quality Data and Ambient Concentrations for Ozone and

Particulate Matter,” January 7, 2003, Air Docket A-2001-11, Document No. IV-B-05.

References for Chapter 2
Final Regulatory Support Document

2-30

12.Memorandum to Docket A-2001-11 from Fred Dimmick, Group Leader, Air Trends Group,

“Summary of Currently Available Air Quality Data and Ambient Concentrations for Ozone and

Particulate Matter,” January 7, 2003, Air Docket A-2001-11, Document No. IV-B-05.

13.National Air Quality and Emissions Trends Report, 1998, March, 2000, at 28. This document

is available at http://www.epa.gov/oar/aqtrnd98/. Relevant pages of this report can be found in

Memorandum to Air Docket A-2000-01 from Jean Marie Revelt, September 5, 2001, Document

No. II-A-63.

14.U.S. EPA, 1995, Review of National Ambient Air Quality Standards for Nitrogen 

Dioxide, Assessment of Scientific and Technical Information, OAQPS Staff Paper, 

EPA-452/R-95-005.

15.U.S.EPA, 1993, Air Quality Criteria for Oxides of Nitrogen, EPA/600/8-91/049aF.

16.Much of the information in this subsection was excerpted from the EPA document, Human

Health Benefits from Sulfate Reduction, written under Title IV of the 1990 Clean Air Act

Amendments, U.S. EPA, Office of Air and Radiation, Acid Rain Division, Washington, DC

20460, November 1995. Air Docket A-2000-01, Document No. II-A-32.

17.Vitousek, Peter M., John Aber, Robert W. Howarth, Gene E. Likens, et al. 1997. Human

Alteration of the Global Nitrogen Cycle: Causes and Consequences. Issues in Ecology. Published

by Ecological Society of America, Number 1, Spring 1997.

18. 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 document is available on the internet at

http://www.nap.edu/books/0309048443/html/. 

19.Much of this information was taken from the following EPA document: Deposition of Air

Pollutants to the Great Waters-Second Report to Congress, Office of Air Quality Planning and

Standards, June 1997, EPA453-R-97-011.

20.Terrestrial nitrogen deposition can act as a fertilizer. In some agricultural areas, this effect can

be beneficial.

21.EPA (1996) Review of the National Ambient Air Quality Standards for Particulate Matter:

Policy Assessment of Scientific and Technical Information OAQPS Staff Paper. EPA452-R-96-

013. Docket Number A-2001-11, Document No. II-A-52. The particulate matter air quality

criteria documents are also available at http://www.epa.gov/ncea/partmatt.htm.

22.Memorandum to Docket A-2001-11 from Fred Dimmick, Group Leader, Air Trends Group,

“Summary of Currently Available Air Quality Data and Ambient Concentrations for Ozone and

Particulate Matter,” January 7, 2003, Air Docket A-2001-11, Document No. IV-B-05.
Chapter 2: Health and Welfare Concerns

2-31

23.See the Final Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle Standards and

Highway Diesel Fuel Sulfur Control Requirements, Document EPA420-R-00-026, December

2000. Docket A-2000-01, Document No. II-A-13. This document is also available at

http://www.epa.gov/otaq/diesel.htm#documents.

24.Memorandum to Docket A-99-06 from Eric O. Ginsburg, Senior Program Advisor,

“Summary of Absolute Modeled and Model-Adjusted Estimates of Fine Particulate Matter for

Selected Years.” December 6, 2000. Air Docket A-2001-11, Document No. II-A-61.

25.U.S. EPA (2000) Health Assessment Document for Diesel Exhaust: SAB Review Draft. 

EPA/600/8-90-057E Office of Research and Development, Washington DC. This document is

available electronically at http://cfpub.epa.gov/ncea/cfm/dieslexh.cfm.

26. Coburn, R.F. (1979) Mechanisms of carbon monoxide toxicity. Prev. Med. 8:310-322.

27.Helfaer, M.A., and Traystman, R.J. (1996) Cerebrovascular effects of carbon monoxide. In: 

Carbon Monoxide (Penney, D.G., ed). Boca Raton, CRC Press, 69-86.

28. Benignus, V.A. (1994) Behavioral effects of carbon monoxide: meta analyses and

extrapolations. J. Appl. Physiol. 76:1310-1316. Docket A-2000-01, Document IV-A-127.

29.The CO Criteria Document (EPA 600/P-99/001F) contains additional information about the

health effects of CO, human exposure, and air quality. It was published as a final document and

made available to the public in August 2000 (www.epa.gov/ncea/co/). A copy of this document

is also available in Docket A-2000-01, Document A-II-29.

30.National Air Quality and Emissions Trends Report, 1999, EPA, 2001, at Table A-19. This

document is available at http://www.epa.gov/oar/aqtrnd99 The data from the Trends report are

the most recent EPA air quality data that have been quality-assured. A copy of this table can also

be found in Docket No. A-2001-11, Document No. II-A-59.

31. National Air Quality and Emissions Trends Report, 1998, March, 2000; this document is

available at http://www.epa.gov/oar/aqtrnd98 National Air Pollutant Emission Trends, 1900-

1998 (EPA454-R-00-002), March, 2000. These documents are available at Docket No.

A-2000-01, Document No. II-A-72. See also Air Quality Criteria for Carbon Monoxide, U.S.

EPA, EPA 600/P-99/001F, June 2000, at 3-10. Air Docket A-2001-11, Document Number

II-A-58. This document is also available at http://www.epa.gov/ncea/coabstract.htm.

32.The more stringent standards refer to light light-duty trucks greater than 3750 pounds loaded

vehicle weight, up through 6000 pounds gross vehicle weight rating (also known as LDT2).

33.Old endnote 36.

34.Old endnote 37.

35. National Research Council, 1993 (Ibid).
Final Regulatory Support Document

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36.National Research Council, 1993 (Ibid).

37. National Acid Precipitation Assessment Program (NAPAP), 1991. Office of the Director. 

Acid Deposition: State of Science and Technology. Report 24, Visibility: Existing and Historical

Conditions - Causes and Effects. Washington, DC. Cited in US EPA, Review of the National

Ambient Air Quality Standards for Particulate Matter: Policy Assessment of Scientific and

Technical Information. OAQPS Staff Paper. EPA452-R-96-013. This document is available in

Docket A-99-06, Document II-A-23. Also, US EPA. Review of the National Ambient Air

Quality Standards for Particulate Matter: Policy Assessment of Scientific and Technical

Information, OAQPS Staff Paper. Preliminary Draft. June 2001. Docket A-2000-01, Document

IV-A-199.
Chapter 3: Industry Characterization

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CHAPTER 3: Industry Characterization

To help assess the potential impact of this emission-control program, it is important to

understand the nature of affected industries. This chapter describes the Category 3 marine diesel

engine and vessel industries. The picture that emerges is one of a fairly concentrated market,

with only four companies producing over 75 percent of all Category 3 marine diesel engines

worldwide and shipyards in only three countries producing over 60 percent of all vessels that use

these engines. Through Caterpillar’s acquisition of MaK, the United States now has a presence

in the C3 marine diesel engine market, although no engines are currently produced in the United

States. The U.S. share of the world market of vessel construction, however, is very small. This

is mainly due to the shipyard subsidy policies of other governments. Because the United States

does not provide similar subsidies most, if not all, of U.S. ship production is vessels required

under the Jones Act to be built in the United States.

This chapter concludes with a brief profile of the vessels that enter U.S. ports. Analysis of

national port entrance data indicates that the vast majority of Category 3 vessels that enter U.S.

ports are flagged or registered in other countries. We do not attempt to perform this analysis on a

port-specific basis. However, given the small number of U.S. vessels in comparison with the

world fleet, it is likely that the contribution of U.S. vessels with Category 3 engines to local air

pollution in any given port is likely to be small compared with that of foreign vessels.

It should be noted from the outset that it is difficult to obtain reliable data on engine

construction, vessel construction, fleet size, and port activity levels. While there are several

sources available through various government agencies (e.g., Coast Guard, the Maritime

Administration) and industry groups, the data they provide are often inconsistent or incomplete. 

There are also differences in what these groups count and how they count it. Therefore, the

numbers contained in this chapter should be interpreted as approximations and not as definitive

counts. However, because of the differences in magnitude between U.S. and foreign

manufacture of engines, vessels, and fleet sizes, the observations we make about these sectors

remain valid.

We provided an industry characterization for Category 1 and Category 2 marine diesel

engines in the Final Regulatory Impact Analysis document for our 1999 rule.1

3.1 Description of Category 3 Marine Engines

For large ocean-going vessels, it is common for the ship to have multiple engines. The

primary purpose of the engines is to provide propulsive power to propel the vessel. Engines are

also required to generate electrical power to be used for auxiliary purposes such as navigation

equipment, maneuvering equipment, and crew services. Marine engines have traditionally been

diesel- or steam-powered engines. Since 1980, virtually all large marine engines built have been

diesel.
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EPA defines Category 3 marine engines as compression-ignition (i.e., diesel) engines with a

displacement greater than or equal to 30 liters per cylinder. Steam engines are not considered

Category 3 engines. Category 3 engines can be incredibly large. These engines are equipped

with anywhere between four to 14 cylinders with displacement ranging from 30 liters per

cylinder up to 2000 liters per cylinder and output between 2,000 kW to over 100,000 kW. There

are two common types of Category 3 engines: “low-speed” (e.g., engine speed of 150 rpm or

less) and “medium-speed” (e.g., engine speed of approximately 300 rpm). Low-speed engines

are two-stroke models which are connected to a direct drive propulsion system. The mediumspeed engines are typically four-stroke engines (a very small percentage are two-cycle). These

engines are commonly connected to an electric drive propulsion system. The electric drive

system is actually a large electrical generator that can also be used to generate auxiliary power as

well drive the propulsion system.

Another important characteristic of Category 3 diesel engines is that they generally operate on

a very low-grade petroleum-based fuel called “bunker” or “residual” fuel. This fuel is the

remnant fuel left over from the refinery process of making gasoline, diesel, and other petroleum

fuels. It is inexpensive and contains high levels of sulfur and nitrogen. Because of its high level

of paraffins, bunker fuel is solid at ambient temperature. Therefore, the fuel has to be heated in

order for it to become a liquid which can be combusted in the engine. As a result, vessels using

Category 3 engines are equipped with elaborate fuel storage and handling systems. This is

described in greater detail in Section 8.1.2 of Chapter 8. 

 There is usually a distinction between the engines used for propulsion and the engines used

to generate electrical power for navigation equipment (radar, gyrocompass, telecommunications),

maneuvering equipment (steering gear, bow thrusters) and crew services (lighting & cooking). 

The engines used to generate electrical power are typically Category 2 diesel engines (5-30 liters

per cylinder). Some vessels, such as refrigerated cargo vessels (“reefers”) may require Category

3 engines to meet electric power requirements. Examples of this are the Dole Columbia and

Dole Chile which are equipped with MaK M32 engines (39 liters per cylinder) as generators.2

Cruise ships often employ diesel-electric engines, discussed above, that provide both propulsion

and power generation. In addition to propulsion and electric power engines, an auxiliary engine

is typically installed for emergency use. 

Category 3 marine diesel engines are unique among engines in the sense that they are very

large and are not typically mass-produced. They also come in a broad configuration of models:

varying number of cylinders, engine displacement, power output, and engine speed. Because

there are so many different vessel applications and such a large selection of available engine

configurations, the engine selection is a major design consideration in the overall design of a

vessel. As a result, the engine selected for a specific vessel is often a unique design or

configuration that is built specifically for that vessel.

Once a vessel manufacturer has determined the size and output of the engine necessary for a

particular vessel design, the engine manufacturer develops the engine on a test bed. After engine

development is completed, the engine is assembled and tested. The tests consists of making sure
Chapter 3: Industry Characterization

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the engine starts and operates properly. Certification testing to demonstrate compliance with the

MARPOL Annex VI NOx limits may also occur at this time. The engine is disassembled and

shipped to the shipyard where the vessel is to be built. The shipyard or an approved licensed

assembler reassembles the engine and fits it into the vessel and connects it the propulsion system.

This is typically done with engine manufacturer supervision.

Once the vessel is complete, the shipyard will typically perform a series of three more engine

tests. The first is referred to as “light-off,” which is when the engine is started for the first time

in the vessel. The second engine test is dock testing, where the engine is operated in dock to

make sure that all systems are operational. The third test is sea testing, where the vessel is taken

out on it’s “maiden voyage.”

3.2 Category 3 Marine Engine Manufacturers

3.2.1 Companies That Make Category 3 Marine Engines

Category 3 engine manufacturers are generally large, multi-national, diversified companies

which also produce smaller marine engines, marine propulsion and marine electric generation

equipment. In addition, these companies produce engines for other uses such as locomotives and

power plants. Many have divisions which manufacture vessels and operate shipyards.

We have identified 16 companies that manufacture Category 3 marine diesel engines. Four

large companies (MAN B&W Diesel, Wartsila/New Sulzer, Catepillar/MaK, and Mitsubishi)

dominate the sales of Category 3 engines. These four companies account for nearly 75 percent of

medium-speed engine sales and 100 percent of low- speed engine sales. The remaining 25

percent of medium-speed engine sales are distributed among the other 12 engine manufacturers. 

Category 3 diesel engine manufacturers are located primarily in Europe and Japan. Only one

engine company (Caterpillar) which manufactures Category 3 diesel engines is headquartered in

the United States. Caterpillar recently purchased MaK located in Kiel, Germany. However,

Caterpillar does not manufacture any Category 3 diesel engines in the United States. Therefore,

there are no Category 3 engines manufactured in the United States. 

Table 3.2-1 is a list of engine manufacturers which produce Category 3 engines. This list was

compiled from the Directory of Marine Diesel Engines.

3
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Table 3.2-1 Current Worldwide Manufacturers of Category 3 Marine Diesel Engines

Akasaka Diesels Mitsubishi Heavy Industries Ltd

Caterpillar Motoren GmbH & Co., KG Mitsui Engineering & Shipbuilding Co. Ltd

Daihatsu Diesel Mfg. Co., Ltd. Niigata Engineering Co Ltd, Japan

Fincantieri Diesel Rolls-Royce

Hanshin Diesel Works Ltd SEMT Pielstick

Makita Corp SKL Motoren-und Systemtechnik GmbH

MAN B&W Diesel Wärtsilä/New Sulzer

Matsui Iron Works Co.,Ltd. Yanmar Diesel Engine Co., Ltd

3.2.2 Production of Category 3 Marine Engines

Shipbuilding is a multi-year process, therefore the number of engines produced per year is not

generally tracked by the shipping industry. The number of engines “produced” in a given year is

reported as the number of engine installations on vessels which are delivered in that year. This

number reflects the number of engines installed for propulsion power, not electric generating or

auxiliary power. 

Due to the size and complexity of the engine manufacturing companies, it is difficult to

obtain sales and production data for individual engine models or classes. Most companies which

were researched only report annual income at the division level. It is not appropriate to compare

these sales data since the types of activities and structure of a given division vary greatly between

companies. In addition, many of the engines provided by these manufacturing companies are

used for other applications other than marine propulsion and power, such as locomotive and

land-based electric power generation.

We estimated the number of propulsion engines installed annually by each manufacturer

based on information in Motorship’s Annual Analysis publication for 1998.4

 The Annual

Analysis data are based on a survey of ships with dead weight tonnage (DWT) greater than 2,000

that were delivered in that year. These data are presented in Table 3.2-2. The analysis gives the

number of engines installed on all vessels by manufacturer. Note that several of the companies

are now owned or controlled by other manufactures including Sulzer (Wärtsilä), Bergen (Rolls

Royce), MaK (Caterpillar), Rushton (MAN B&W). Table 3.2-3 indicates that for 1998,

approximately 765 low-speed engines and 497 medium-speed engines were produced for a total

of 1,262 Category 3 engines worldwide.
Chapter 3: Industry Characterization

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Table 3.2-2 

Summary of Worldwide Category 3 

Engine Manufacturer Production for Vessels of >2,000 DWT in 1998

LOW-SPEED ENGINES MEDIUM-SPEED ENGINES

Manufacturer Engines Percent of Total Manufacturer Engines Percent of Total

MAN B&W 515 67.3% Wärtsilä 135 27.2%

Sulzer 150 19.6% MAN B&W 92 18.5%

Mitsubishi 100 13.1% MaK 75 15.1%

Caterpillar 32 6.4%

Sulzer 24 4.8%

Bergen 21 4.2%

Deutz MWM 20 4.0%

GMT 19 3.8%

Ruston 15 3.0%

Hanshin 13 2.6%

MTU 9 1.8%

Niigata 9 1.8%

Yanmar 7 1.4%

Pielstick 6 1.2%

Akasaka 6 1.2%

Unknown 5 1.0%

SKL 4 0.8%

Daihatsu 3 0.6%

Russki 2 0.4%

Total 765 Total 497 0.4%

Source: Motorship, Annual Analysis
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Table 3.2-3

Top 10 Licensees of Category 3 Engines for Years 1999 and 2000

Yard Nationality Licensee Manufacturer No of Engines

1999

JAPAN Mitsui Engineering & Shipbuilding Co Ltd MAN B&W DIESEL A/S 117

S. KOREA Hyundai Heavy Industries Co MAN B&W DIESEL A/S 93

JAPAN Kawasaki Heavy Industries Ltd MAN B&W DIESEL A/S 45

JAPAN DIESEL UNITED SULZER 45

JAPAN Hitachi Zosen Corp MAN B&W DIESEL A/S 31

S. KOREA Sasung Heavy Industries Co MAN B&W DIESEL A/S 28

NORWAY WÄRTSILÄ FINLAND WÄRTSILÄ 26

S. KOREA Korea Heavy Industries & Construction Co MAN B&W DIESEL A/S 25

FINLAND WÄRTSILÄ FINLAND WÄRTSILÄ 23

CHINA Hudong Heavy Machinery Co MAN B&W DIESEL A/S 19

2000

JAPAN Mitsui Engineering & Shipbuilding Co Ltd MAN B&W DIESEL A/S 107

S. KOREA Hyundai Heavy Industries Co MAN B&W DIESEL A/S 101

JAPAN Kawasaki Heavy Industries Ltd MAN B&W DIESEL A/S 48

JAPAN DIESEL UNITED SULZER 43

JAPAN Hitachi Zosen Corp MAN B&W DIESEL A/S 42

ITALY WÄRTSILÄ FINLAND WÄRTSILÄ 33

S. KOREA Hyundai Heavy Industries Co SULZER 28

CHINA WÄRTSILÄ FINLAND WÄRTSILÄ 26

JAPAN HANSHIN HANSHIN 24

GERMANY MaK MaK 22

Source: Motorship, Annual Analysis

3.2.3 Relationship Among Worldwide Engine Manufacturers

Engine manufacturing companies are often involved with financial and design agreements

with other engine manufacturers. The types of associations included component manufacturing

licensing agreements, engine licensing agreements, controlling stock ownership of other

companies, and acquisitions. The following acquisitions occurred in recent years: Rolls Royce

acquired Bergen, Wärtsilä acquired Sulzer, Caterpillar acquired MaK, MAN B&W acquired

Alstom (Mirrlees Blackstone and Ruston).

Licensing agreements also exist between the manufacturers and the shipyards. These

licensing agreements generally are for a model design. Engines are vessel-specific and are field

erected during installation on a vessel. The shipyard typically assembles the engine within the

vessel at the shipyard per the engine manufacturers instructions.

Licensee information was also reported in the Motorship database. We compiled a list of the

licensees based on the manufacturer, the location and the number of engines installed for years

1999 and 2000. This information is presented in Table 3.2-3 for the top 10 licensees. Notice that

the top five licensees are the same for both years.
Chapter 3: Industry Characterization

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3.3 Vessel Manufacturers

This section gives a general characterization of the large-vessel manufacturing segment of the

marine industry that may be impacted by this final rule. This industry characterization was

developed in part under contract with ICF Consulting5 as well as independent analyses conducted

by EPA through interaction with the industry and other sources.

3.3.1 United States Vessel Manufacturers

3.3.1.1 Description of Vessels

This section characterizes U.S. manufacturers of large commercial vessels equipped with

Category 3 engines. These vessels engage in waterborne trade and/or passenger transport and

typically exceed 400 feet in length and/or weigh more than 2,000 gross tons. The U.S.

Department of Transportation Maritime Administration (MARAD) identifies a major shipbuilder

as one that is capable of producing a ship of 400 feet in length or greater. Commercial vessels

operate in the Great Lakes, coastwise, intercoastal, and/or transoceanic routes. The principal

commercial vessel types are auto carriers, bulk carriers, container ships, general cargo ships,

refrigerator ships, roll-on/roll-off (ro ro), tankers, and passenger ships. Passenger ships include

cruise ships and large ferries.

3.3.1.2 Production of Large Vessels Equipped with Category 3 Marine Diesel Engines

The process of designing and building a large vessel is long and complicated. The whole

process takes approximately 32 to 36 months. Once a fleet owner decides to build a new ship,

they work with a shipyard and engine manufacturer to design the ship. The design process is the

most time consuming part of the shipbuilding process and can take up to 18 months. In the early

stages of the design process, the owner works with ship architects and classification societies that

ensure that the design and materials to be used for the vessel meet appropriate performance and

safety specifications. An example of a U.S. classification society is the American Bureau of

Shipbuilding (ABS). It is also during the design process that the owner and architects decide

what engines to use. In determining the appropriate propulsion engine for the specific vessel

design, they consider engine type (e.g., medium- or slow-speed), engine size, and power output

to name a few. Once a design has been approved and completed, the actual construction of the

vessel begins. This process takes place at a shipyard and can take between 12 and 14 months. 

3.3.1.3 Background of the U.S. Shipbuilding Industry and Global Competition

Shipbuilding has historically been an important industry in the United States. However,

according to the American Shipbuilding Association (ASA), the U.S. shipbuilding industry has

been contracting since 1980. In 1981, there were 22 shipyards holding ship construction

contracts for the government, commercial customers, or both. By 2001, the number of active

new construction shipyards building large oceangoing vessels fell to three.
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The vast majority of commercial ships used throughout the world are built in other countries. 

A major shift in shipbuilding market share began in the 1960s with Japan’s entry into the market. 

South Korea entered the market in the1970s, and China entered in 1980. Few ships have been

built in the U.S. since the boom years in the mid 1970's through the mid 1980's. Between 1987

to 1989, no commercial ships were built at U.S. shipyards. Since 1990, approximately 19 large

commercial ships that use Category 3 engines have been built in the U.S., for an average of 1.9

ships per year. The ASA believes that the collapse of commercial shipbuilding in the United

States was largely due to the elimination of the Construction Differential Subsidy Program

(CDS) in 1981. The CDS program, established in 1936 and administered by MARAD, provided

for a subsidy of up to 50 percent of the construction cost of a commercial vessel built in the

United States to offset the lower foreign construction costs. The subsidy was only available for

those ships built in the United States that were to be registered under the laws of the United

States, and operated in the international trades. The United States was the only shipbuilding

country in the world to eliminate its subsidies as Asia and Europe dramatically increased

subsidies to their industries. As a result, the U.S. lost its international commercial market share,

which was at nine percent. U.S. commercial business is today comprised of construction of ships

to serve our domestic coastwise trade. This market accounts for about one percent of the

worldwide commercial market. Figure 3.3-1 illustrates the change in the distribution of the

world’s commercial shipbuilding tonnage.

A moderate resurgence in U.S. commercial orders began in 1995 as a result of demand for

replacement tonnage for the U.S. domestic coastwise trade, known as Jones Act Vessels (which

requires ships transporting cargo between two U.S. points to be U.S. built, owned and crewed;

see below) and the revitalization of the Title XI Ship Loan Guarantee Program (a government

ship loan guarantee program administered by MARAD). 

1979

Rest of World

65%

Japan

23%

South Korea

3%

United States

9% China

0%

2001

Rest of World

24%

Japan

26%

South Korea

42%

United States

1%

China

7%

Figure 3.3-1: World Commercial Shipbuilding Tonnage
Chapter 3: Industry Characterization

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Both commercial and naval shipbuilding are cyclical. This mix of commercial and military

shipbuilding orders has been the cornerstone of the shipbuilding industrial base in the United

States. Between 1955 and 1985, U.S. shipbuilders delivered an average of 20 commercial ships

per year for both domestic and international trades. Between the same period, the U.S. Navy

ordered an average of 19 ships per year.

Table 3.3-1 presents the delivery of merchant and military vessels from U.S. shipyards over

the ten year period between 1990 and 2000 according to the Colton company.6

Table 3.3-1 

Deliveries from U.S. Shipyards, 1990 to 2000

(Merchant ships over 1000 Gross Tons and Naval ships over 1000 LT)

Merchant

(No. of ships)

Merchant

(1000GT)

Naval

(No. of ships)

Naval

(1000LT)

1990 0 0 14 102

1991 0 0 14 100

1992 3 45 18 218

1993 0 0 18 129

1994 1 17 15 158

1995 1 2 17 221

1996 1 28 11 92

1997 4 107 11 186

1998 2 24 11 251

1999 6 161 5 90

2000 1 7 8 134

Source: The Colton Company

3.3.1.4 Cabotage Laws in the United States: The Jones Act and the Passenger Vessel

Services Act

The term “cabotage,” (derived from the French “caboter,” meaning to sail coast-wise, or

literally, “by the capes”) refers to a body of maritime law dealing with the right to conduct trade

or transport goods in coastal waters or between two points within a country. These laws,

common in some form in more than 40 nations with significant ocean-going fleets, are designed

to ensure a strong national merchant marine fleet for defense, employment, and general economic

purposes by reserving a country’s domestic maritime transportation for its own citizens. 

Cabotage laws are designed to guarantee the participation of a country’s citizens in its own
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domestic trade. These laws foster the development of a merchant marine and give preference to

local labor and industry. They also support national security and protect the domestic economy. 

Cabotage laws in the U.S. date back to 1789, when Congress first restricted participation in

coastal trades and fisheries to U.S.-built and U.S.-owned vessels and gave these vessels

preferential treatment regarding taxes and import duties. Currently, U.S. maritime cabotage laws

include a number of different statutes that govern the transportation of cargo and passengers

between two points in the U.S. (including its territories and possessions), as well as all dredging,

towing, salvage, and other marine operations and fishing. Two major enactments, The Merchant

Marine Act of 1920 (46 U.S.C. 861) and the Passenger Vessel Services Act of 1886 (46 U.S.C.

289), in combination provide the majority of U.S. cabotage provisions related to the transport of

cargo or passengers. Variations of these laws exist today in the U.S. transportation,

communications, and utility industries. 

Section 27 of the Merchant Marine Act of 1920 (46 U.S.C. 883; 19 CFR 4.80 and 4.80b),

popularly known as the “Jones Act,” essentially requires that domestic waterborne commerce

between two points within the U.S. and subject to coastwise laws must be transported in vessels

built in the U.S., documented under the laws of the U.S. (i.e., registered under the American

flag), and crewed and owned by U.S. citizens. The Passenger Vessel Services Act sets

essentially the same standards for passenger vessels as the Merchant Marine Act sets for cargo

vessels. Specifically, the primary requirements of the Jones Act state that:

• No merchandise may be transported by water between points in the U.S., either directly or via

a foreign port, unless the transporting vessel is built in the U.S., documented under the laws

of the U.S., and owned by U.S. citizens.

• A foreign vessel can pick up or deliver cargo at a U.S. port, but it can’t pick up cargo in one

U.S. port and deliver the same cargo to another U.S. port, even if the vessel stops at a foreign

port in the mean time.

• Vessels over 200 gross tons with domestic U.S. trading privileges that are sold to foreign

owners or registered under a foreign flag may return to being U.S.-flagged, but the vessel’s

domestic U.S. trading privileges are forever forfeited. 

• Vessels with domestic U.S. trading privileges which are rebuilt may only retain those

privileges if the entire rebuilding is performed within the U.S. 

In addition, Congress included some exceptions to the requirements of the Jones Act to deal with

special circumstances. These provisions include service on the Yukon River, established ferry

services owned by railroad companies, transport of empty cargo accessory equipment, transfers

of cargo between barges of the same owner, and transport of fish processing supplies. The

provisions of the U.S. cabotage laws may be waived administratively by the Treasury Department

only in the interest of national defense. The only other way in which the provisions may be

waived and a non-qualifying vessel granted domestic trading privileges is via Congressional

action. 
Chapter 3: Industry Characterization

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The Jones Act fleet, or those vessels engaged in or otherwise authorized to be engaged in

U.S. domestic commerce, is a subset of the fleet of U.S. vessels. In other words, all Jones Act

vessels are U.S.-flagged, but not all U.S.-flagged vessels are necessarily endorsed to engage in

domestic commerce. For example, as noted above, a formerly U.S.-flagged vessel could, after a

period of being registered under a foreign flag, return to being U.S.-flagged, but that vessel will

never be able to engage in U.S. domestic shipping. 

There are tens of thousands of Jones Act vessels that operate in three major sectors of U.S.

domestic shipping: the Great Lakes, the inland waterways, and the domestic ocean trades (along

the coasts or non-contiguous trade between the U.S. mainland and Puerto Rico, Alaska, Hawaii,

and other U.S. Pacific islands). The vast majority of these, however, are non-self-propelled dry

cargo barges and tanker barges that ply the U.S. internal waterways. As of July 1998 there were

about 61 self-propelled merchant vessels of 1,000 gross registered tons with unrestricted

domestic trading privileges (i.e., Jones Act vessels).7

3.3.1.5 U.S. Vessel Manufacturers

MARAD uses the Major Shipbuilding Base (MSB) to track the U.S. shipbuilding industry. 

The MSB is defined as those privately owned shipyards that are open and have at least one

shipbuilding position capable of accommodating a vessel 122 meters (400 feet) in length or over

(vessels of this size are generally considered by the shipbuilding industry to be very large deepsea vessels; many of these would use Category 3 engines). The shipyard must also have in place

a long-term lease on the shipbuilding facility and there must be no dimensional obstructions

(i.e., locks, bridges) in the waterway leading to open water. As of January 1, 1998, utilizing this

definition, there were 18 major shipbuilding facilities in the United States. However, the

majority of these shipyards produce military vessels or smaller commercial vessels that do not

use category 3 engines.

According to the ASA, there are eight shipyards that have built large category 3 enginepowered commercial vessels over the last several years. Only three of these shipyards are

currently building vessels. Table 3.3-2 lists the eight shipyards that have most recently been

involved in building large commercial vessels.
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Table 3.3-2

U.S. Shipyards Building Large Commercial Vessels 

Shipyard Location

National Steel & Shipbuilding Co. San Diego, CA

Avondale Industries, Inc. Avondale, LA

Ingalls Shipyard Pascagoula, MS

Newport News Shipyard Newport news, VA

Kvaerner Philadelphia Shipyard, Inc. Philadelphia, PA

Friede Goldman Halter Pascagoula, MS

Alabama Shipyard, Inc. Mobile, AL

Todd Shipyards Seattle, WA 

The three shipyards currently building large commercial vessels are National Steel &

Shipbuilding Co., Avondale Industries, Inc., and Ingalls Shipyard. A fourth shipyard, Kvaerner

Philadelphia Shipyard, Inc. had a long history of producing large oceangoing vessels, primarily

for the Navy, but was closed in 1996. In 1997, Kvaerner signed an agreement with the city of

Philadelphia and the state of Pennsylvania to re-open the shipyard. While the shipyard is still

sorting out who the owner will be, they have stated that they plan to focus primarily on the

domestic oceangoing cargo ship market. Thus, they may soon be building large ships equipped

with Category 3 engines.

The 18 major shipbuilding facilities tracked by the MSB employ about 65 percent of the

workforce engaged in shipbuilding and/or boatbuilding (SIC 3731). About 43 percent of the

workforce at MSB yards is engaged in military ship construction and repair work. The largest six

shipyards (known as the “big six”) account for over 90 percent of commercial shipbuilding

dollars in the United States and over 98 percent of the U.S. Navy’s shipbuilding budget.8

 Table

3.3-3 presents the employment and sales for the largest U.S. shipyards still active (or with

capacity) to build large commercial vessels by yard. Table 3.3-4 presents similar information

related to the parent companies.
Chapter 3: Industry Characterization

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Table 3.3-3 Employment and Sales for the Largest U.S. Shipyards 

Active (or With Capacity) in Building Large Commercial Vessels 

Shipyard

Shipyard Total

Employment

Shipyard Total

Sales

(millions $)

Comments

National Steel & Shipbuilding Co. 5,000 $500 currently engaged in commercial

shipbuilding; about half of employment

and sales is commercial shipbuilding

and repair

Avondale Industries, Inc. 5,000 $625 currently engaged in commercial

shipbuilding

Ingalls Shipyard 10,000 $1,300 currently engaged in commercial

shipbuilding

Newport News Shipyard 18,000 $1,800 In 2000 ended its commercial

shipbuilding practice, but has

capacity

Kvaerner Philadelphia Shipyard, Inc. n/a n/a Employment available for parent

company only

Friede Goldman Halter n/a n/a Filed for bankruptcy April 2001

Alabama Shipyard, Inc. n/a n/a Has commercial capability, but

focuses on military construction

Todd Shipyards, Seattle 500-1,000 n/a Has commercial capability, but

focuses on ferry construction
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Table 3.3-4 Employment and Sales for the Parent Companies of Largest U.S. Shipyards 

Active (or With Capacity) in Building Large Commercial Vessels 

Parent Company Shipyard(s) Parent Company Total

Employment

Parent Company Total

Sales

(millions $)

General Dynamics National Steel & Shipbuilding Co.,

Bath Iron Works, and Electric Boat

33,000 $12,000

Northrop Grumman Avondale Industries, Inc., Ingalls

Shipyard, and Newport News

Shipbuilding

100,000 $18,000

Kvaerner-Aker Kvaerner Philadelphia Shipyard,

Inc.

40,000 $6,000

Friede Goldman

Halter

Halter Marine n/a* n/a*

Atlantic Marine Alabama Shipyard, Inc. n/a n/a

Todd Shipyards Todd Shipyards, Seattle 500 - 1,000 n/a

*Filed for bankruptcy April 2001

3.3.1.6 Shipping Outlook

According to the ASA, two factors creating near-term commercial markets for U.S.

shipbuilding are the Jones Act, which requires ships transporting cargo between two U.S. points

to be U.S. built, owned and crewed, and the Oil Pollution Act of 1990 (OPA 90), which requires

all oil tankers calling in U.S. waters by the year 2015 to be equipped with double hulls.2

According to MARAD, shipbuilding analysts expect a significant rise in new orders for

commercial ships. This increase in new orders emanates from projections of high growth in the

seaborne trade for oil and dry bulk cargoes, as well as the continued demand for replacement

ships due to the aging of the world fleet. The average age of the world fleet was 19 years at the

end of 2000. Projected total new worldwide demand for new tonnage between 1998-2010 will

be approximately 339.0 million DWT.7 Another estimate is that worldwide new construction

demand over the 10 year period 2001-2010 may be 230 million DWT, according to Drewery

Shipping.9

 Prior to September 2001, ASA believed that another commercial market opportunity

for U.S. shipbuilders was construction of large oceangoing cruise ships for U.S. domestic trade

as the demand for U.S. coastal cruises grows.2

 In addition, the ASA projected demand over the

next 10 years for 30 dry cargo ships.10

 Worldwide shipyards are seeing and will continue to see an influx of orders for double hulled

tankers, as a result of the requirements of enactment OPA-90. OPA-90 requires that by the year

2015 all tankers entering U.S. ports must be double-hull. According to ASA, since enactment of

OPA-90, U.S. shipyards have built 10 double-hulled tankers with options for two more. United
Chapter 3: Industry Characterization

3-47

States shipbuilders anticipate orders for over 40 double hulled tankers over the next 10 years. 

Recently, ASA projected demand over the next 10 years for 25 40,000-DWT double-hulled

tankers.11 Other analysts are less optimistic, estimating that the commercial shipbuilding

industry overall is over capacity by as much as 30 percent due to distortions from foreign

subsidies.12

3.3.2 International Vessel Manufacturers

There are just over 22 countries that build large Category 3 engine-powered commercial

vessels. In 1998, 1,080 commercial ships with a dead weight tonnage (DWT) of over 2,000 were

built worldwide, including U.S. production. Over 60 percent of those ships were built by three

countries: Japan, South Korea, and China. Germany and Poland round out the five leading

shipbuilding countries. These five countries produced over 70 percent of the large commercial

vessels built in 1998.

3.4 U.S. Fleet Characterization

3.4.1 Background

There are a number of data sources that have information on the U.S. fleet. Of these sources,

the MARAD’s “Vessel Inventory Report” dated July, 2001 was the most reliable and

comprehensive. It contains data for ocean-going, self-propelled merchant vessels of 1,000 gross

tons and over that are flagged or registered in the U.S. The vessel name, ship type, engine type,

the year and country in which the operator (government or private) vessel was built, gross

tonnage, and DWT and whether the vessel is classified a Jones Act vessel by the U.S. are all

identified in the MARAD data. 

3.4.2 U.S. Fleet

Despite the cabotage laws which protect the U.S. shipping industry, the U.S. fleet has been

declining in numbers of vessels and DWT since the end of World War II. The United States now

ranks 17th in number of oceangoing vessels, having fallen from a top-ten ranking just a few years

ago. The U.S. merchant fleet ranks 11th on a deadweight tonnage basis.13 Today, the U.S. fleet's

share of oceanborne commercial foreign trade, by weight, continues to be less than five percent.

The current estimate for the size of the U.S. fleet for vessels using Category 3 diesel engines

is approximately 200 vessels. Table 3.4-1 presents the estimated number of vessels in the U.S.

Fleet with Category 3 diesel engines based on the MARAD data. The table presents data for the

number of privately-owned (commercial) vessels, government-owned vessels, and Jones Act

vessels. There are over 25 different types of U.S. vessels that visited U.S. ports in 1999. The

average age for these vessels was 22.7 years, with the oldest vessel being 95 years old.
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Table 3.4-1 MARAD Summary of U.S. Fleet Vessels for Vessels 2,000 DWT

Total Commercial Government Jones Act

200 163 37 67

3.4.3 Foreign Vessels that Enter U.S. Ports

The current estimate that 7,600 foreign vessels with Category 3 engines enter U.S. ports. 

There are over 25 different types of foreign vessels that visited U.S. ports in 1999. The average

age for these vessels was 14 years, with the oldest vessel being 96 years old.

3.4.4 Cruise Vessels

Cruise ships are very unique vessels. They are passenger vessels designed for extended trips

ranging from several days to weeks. They are quite literally floating towns. They are equipped

not only with overnight rooms, similar to hotel rooms, but they can also have pools, recreational

facilities, exercise clubs, restaurants, night clubs, and even casinos. The largest cruise ships can

exceed 1,000 feet in length, hold up to 5,000 passengers and crew, contain over 1,600 cabins, and

have up to 14 decks. There are twelve companies that account for the majority of cruise ship

activity in U.S. waters. Table 3.4-2 lists these twelve companies.

Table 3.4-2 Major Cruise Ship Companies

Carnival Cruises Princess Cruises

Celebrity Cruises Royal Carribean International

Cunard Europa Cruises Corporation

Holland American Line Tropicana Cruises

International Shipping Partners La Cruise

Norwegian Cruises Palm Beach Casino Line

According to an EPA published Cruise Ship White Paper, the worldwide cruise ship fleet

included more than 223 ships that carried an estimated 9.5 million passengers in 1998. There

are no cruise ships flagged or registered in the United States. The vast majority of cruise ships

that visit U.S. ports are flagged under Liberia, Panama, the Bahamas, and Norway. This EPA

White Paper also stated that by 2003, cruise ship companies plan to add 33 new and/or bigger

cruise ships to the market, which would increase passenger capacity by 35 percent.

According to ASA, the downturn of the U.S. economy which began in late 2000 started to

take it’s toll on the U.S. tourism industry, and the September 11th attacks on the U.S. sent the

cruise market into a tailspin with decreased bookings, increased cancellations, and many

companies offering huge fare discounts. As a result, two smaller cruise lines, Renaissance
Chapter 3: Industry Characterization

3-49

Cruises and American Classic Voyages have filed for Chapter 11 bankruptcy reorganization, and

the financial viability of other cruise lines are threatened by the free fall in bookings and stock

prices. U.S. shipbuilders began to feel the aftermath of the September 11th attacks on October

25, 2001, when Ingalls Shipbuilding announced that it had stopped work on Project America, a

cruise ship program to build two 1,900-passenger cruise ships. 

3.5 U.S. Port Activity

3.5.1 Background

3.5.1.1 Major U.S. Ports

According to MARAD, the top five major U.S. commercial ports, based on the total number

of calls made to each port, are Los Angeles, Houston, New Orleans, New York, and San

Fransico. Table 3.5-1 lists the total number of calls for each of these five ports, their world

ranking, and the number of calls for the four most common ship types. This table indicates that

the majority of dry goods and products entered and left the U.S. through Los Angeles, New York

and San Fransico, while the majority of oil and other tanker-carried products entered and left the

U.S. primarily through Houston and New Orleans. 

Table 3.5-1 Top Five U.S. Commercial Ports in 2000 - Based on Calls

Port Total Calls World

Ranking

Tankers Dry Bulk Containership Other General

Cargo

Los Angeles 5,326 10 911 783 2,955 677

Houston 5,129 12 2,988 748 614 779

New Orleans 5,090 13 1,371 2,676 388 655

New York 4,605 15 1,271 301 2,172 861

San Fransico 3,575 18 787 626 1,936 226

3.5.1.2 Number of Vessels Visiting U.S. Ports Each Year

According to MARAD, about 7,600 foreign vessels with Category 3 engines visited U.S.

ports in 1999. When the U.S. fleet of 200 vessels is added, this means that about 97 percent of

the total number of Category 3-powered vessels that made calls to U.S. ports were by foreign

vessels. U.S. vessels accounted for only about three percent of the total number of vessels

visiting U.S. ports. Table 3.5-2 lists U.S. vessel types for 1999 and the number of each type.
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Table 3.5-2 MARAD Summary of U.S. Vessels Visiting U.S. Ports 

Vessel Type Number of Vessels

Containership 59

RO/RO 41

Tanker 39

Tug Barge 15

Freighter 14

Bulk Carrier 12

Chemical Tanker 10

Combo Pass & Cargo 5

Heavy-Lift Carrier 4

Car Carrier 2

Total 200

3.5.1.3 Number of Entrances to U.S. Ports

The term “entrance” and “call” are often used interchangeably within the marine industry. An

“entrance” is often defined as a vessel entering a port/waterway area. A “call” is defined as one

entrance and one clearance by a vessel. Because the MARAD data set is the most comprehensive

and since they list the number of entrances and not calls, we looked at entrances as a measure of

how many visits were made by individual vessels. The number of entrances made into U.S.

ports is overwhelmingly dominated by foreign vessels. As stated above, 7,800 vessels visited

U.S. ports in 1999. These vessels made a total of 75,700 entrances to U.S. ports. Of these

entrances, 67,500 or 89 percent, were made by foreign vessels. Only 8,200 entrances or 11

percent were made by U.S. vessels.

EPA analysis of MARAD data for vessel entrances into U.S. ports, indicates that a large

percentage of visits made to U.S. ports are made by a relatively small percentage vessels that

make many visits. For example, when looking at those vessels that made at least three entrances

into U.S. ports in 1999, 50 percent of the total entrances made into U.S. ports were made by only

12 percent of the total vessels making visits. Seventy five percent of all the entrances were made

by only 29 percent of the total vessels. This trend was apparent for both U.S. and foreign vessels. 

This indicates that the majority of the vessels visiting U.S. ports only make a couple of visits per

year, while a relatively small population of vessels are making numerous visits each year. Figure

3.5-1 is a graph of the number of entrances versus the number of vessels (U.S. and foreign) for

1999.
Chapter 3: Industry Characterization

3-51

0

200

400

600

800

1000

1200

1400

1600

Number Ships

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Number Entrances

Figure 3.5-1: Vessel Entrances for 1999 - All Vessels

3.5.2 Cruise Ship Activity

As stated earlier, in 2000 the worldwide cruise ship fleet included more than 223 ships that

carried an estimated 9.5 million passengers in 1998. In 2000, 8 million embarkations occurred

from ports worldwide. Embarkations from U.S. ports accounted for about 67 percent of total

worldwide embarkations. The port of Miami, Florida alone accounted for 21 percent of

worldwide embarkations. In fact, the port of Miami had more cruise ship embarkations than the

rest of the world combined. Of the top five U.S. ports, three are located in Florida: Miami, Port

Canaveral, and Port Everglades. The other two top U.S. ports are Los Angeles and New York. 

These fives ports alone account for 54 percent of worldwide embarkations. Approximately

600,000 or 7.5 percent of worldwide embarkations occur from other U.S. ports located in Alaska,

Louisiana, Massachusetts, Puerto Rico, and Texas. 

The cruise industry has seen a large increase in popularity over the last decade and the

number of U.S. embarkations has doubled since 1990. In early 2000, industry analysts were

projecting that the number of embarkations would continue to grow. However, as discussed

above, the recent downturn of the U.S. economy had an adverse impact on the U.S. tourism

industry. The September 11th attacks exacerbated this impact, and 2001 was the first year in a

decade in which embarkations actually decreased. According to the Cruise Lines International

Association, the cruise industry has rebounded dramatically since the tragic events of September

2001, and the number of embarkations in 2002 have increased over 2001. The cruise industry is

responding to consumer confidence by continuing to expand its fleet. More than 20 ships are

slated to enter the cruise fleet between fall of 2002 and the end of 2003.14
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3.6 Conclusion

The Category 3 marine diesel engine and vessels industry is relatively concentrated. In 1998

there were approximately 1,300 Category 3 marine diesel engines produced worldwide. Seventyfive percent of those engines were manufactured by four companies. None of these engines are

built in the United States. The overwhelming majority of the vessels that use these engines are

built in South Korea, China, and Japan. U.S. shipyards build about one percent of these vessels. 

This is mainly due to the shipyard subsidy programs of other countries. Because the U.S. does

not provide similar subsidies most, if not all, of U.S. ships produced are vessels required under

the Jones Act to be built in the United States.

The vast majority of Category 3 vessels that enter U.S. ports are flagged or registered outside

the United States. Approximately 200 U.S. vessels with Category 3 engines used U.S. ports in

1999. That represents about three percent of the total number of vessels entering U.S. ports for

that year. Given that the number of U.S. vessels is small in comparison with the world fleet, it is

likely that the contribution of U.S. vessels with Category 3 engines to local air pollution in any

given port is small compared with that of foreign vessels.
Chapter 3: Industry Characterization

3-53

1. EPA420-R-99-026, November 1999.

2. IPC Industrial Press Ltd., Motorship, Jan. 2000.

3. Directory of Marine Diesel Engines, Marine Engineer Review, (MER) April 2001.

4. Annual Analysis, Motorship, June 1999 p. 49-50.

5. ICF Incorporated 1998. “Industry Characterization: Commercial Marine Vessel

Manufacturers,” ICF Incorporated, Contract No. 68-C5-00-10, WAN 211, September

1998, Docket A-97-50, Document II-A-03.

6. The Colton Company. www.coltoncompany.com. Accessed on July 26, 2001

7. MARAD. See http://www.marad.dot.gov/MARAD_statistics/Jact_Sum_0401.html.

8. ICF Incorporated 1998. “Industry Characterization: Commercial Marine Vessel

Manufacturers,” ICF Incorporated, Contract No. 68-C5-00-10, WAN 211, September

1998, Docket A-97-50, Document II-A-03.

9. Potomac Institute for Policy Studies. “Maritech Program Impacts on Global

Competitiveness of the U.S. Shipbuilding Industry and Navy Ship Construction.” PIPS98-4. July 1, 1998.

10. ASA 2001. American Shipbuilding Association. The Defense Shipbuilding Base – An

Industry At Risk. May 2001.

11. ASA 2001. American Shipbuilding Association. The Defense Shipbuilding Base – An

Industry At Risk. May 2001.

12. Potomac Institute for Policy Studies. “Maritech Program Impacts on Global

Competitiveness of the U.S. Shipbuilding Industry and Navy Ship Construction.” PIPS98-4. July 1, 1998.

13. Transportation Institute, “Industry Profile,” http//www.trans-inst.org/ind_profile.html.

14. Cruise Lines International Association. Article in Cruise News. September 10, 2002. 

www.cruising.org.

Chapter 3 References
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Chapter 4: Tier 1 Standards

4-1

CHAPTER 4: Tier 1 Standards

This chapter describes the current state of technology for marine diesel engines greater than

2.5 liters per cylinder. This includes a discussion of the feasibility of meeting the Tier 1

standards. The combustion process and potential technologies are basically the same for all the

marine engine types in this rule including slow-speed, two-stroke engines and medium-speed

four-stroke engines, and will be differentiated only where significant differences exist.

4.1 Marine Engine Technology

4.1.1 Diesel Engine Emission Formation

Marine diesel engines, like their land-based counterparts, operate by compressing and cooling

the charge air before it fills the cylinder where fuel is injected, which auto-ignites under pressure. 

In marine engines, the charge air is compressed using a turbocharger under cruising and high

loads and possibly a supercharger driven by the crankshaft at low loads. The charge air is

typically cooled in two stages, first with jacket water and then with a second-stage aftercooler

that relies on a seawater heat exchanger. Fuel is injected with the use of fuel injection pumps on

each cylinder. Individual injection pumps are used so that each cylinder may be independently

optimized for peak performance. The amount of fuel to be injected and fuel injection timing are

typically set at cruising speed with mechanical fuel injection systems. 

Many cylinder and injection parameters determine how the fuel and air mix to prepare for

ignition and combustion, including piston head geometry, injection timing and duration, droplet

sizes, and fuel jet momentum. NOx and PM are the emission components of most concern from

diesel engines. High temperatures and excess oxygen are necessary for the formation of NOx. 

These conditions are found in a diesel engine as the fuel is injected into an oxygen rich

environment, auto-ignites under pressure and multiple flame fronts spread through the

combustion chamber. Typical diesel engine operation includes very high peak temperatures

shortly after the onset of combustion and the nitrogen in the air combines with available oxygen

to form NOx (the relatively high nitrogen content of fuels for Category 3 engines also contributes

directly to NOx emissions during combustion). Because of the presence of excess oxygen,

hydrocarbons evaporating in the combustion chamber tend to be completely burned and HC

emission levels remain low. Similarly, CO emissions, which result from incomplete oxidation of

hydrocarbons from the fuel are kept low by the ample supply of oxygen in the cylinder.

The majority of PM emissions from these engines comes from running on heavy fuel oil

(residual fuel) and the high level of sulfur in the fuel. The highest portion of PM (by weight) is

from ash, metal, oxides, and sulfates (see Table 4.1-1). Carbon soot makes up about a quarter of

the overall PM content. It forms as a result of localized areas where there is not enough oxygen

for complete combustion of fuel droplets while cylinder temperatures are high enough to
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4-2

maintain combustion. A small amount of PM is also from incomplete evaporation and burning

of the fine fuel droplets or vapor and from small amounts of lubricating oil that escape into the

combustion chamber. Engines that operate on distillate fuel generally have a much lower

percentage sulfur and corresponding lower contribution of sulfates, as shown in Table 4.1-1. 

Note that the total amounts of PM in each chart are not the same for the different fuel types.

Table 4.1-1

Comparison of Particulate Emission Composition1

Parameter Truck Diesel Engine 

Operating on Diesel Oil*

Medium-Speed Diesel Engine

Operating on Heavy Fuel Oil*

Carbon soot 35% 25%

Hydrocarbons (fuel oil, lubrication oil) 50% 10%

Ash metal (oxides, sulfates) 15% 65%

Typical value 0.15 g/kW-hr 0.4 g/kW-hr

Measurement method ISO 8178 ISO 9096

*Values are approximate.

In general, controlling both NOx and PM emissions requires different, sometimes opposing

strategies. The key to controlling NOx emissions is reducing peak combustion temperatures,

since NOx forms at high temperatures. In contrast, the key to controlling PM is higher

temperatures in the combustion chamber or faster burning. This reduces PM by decreasing the

formation of particulates and by oxidizing those particulates that have formed. To control both

NOx and PM, manufacturers need to combine approaches using many different design variables

to achieve optimum performance. However, in Category 3 marine engines, whose fuel injection

timing and fuel pressure is often set at cruising speeds, and not optimized at lower loads, there

may be a possibility of reducing emissions of both pollutants through the use of common rail and

electronic controls. 

4.1.2 Category 3 Marine Engine Design and Use

Category 3 marine engines generally fall into one of two distinct types, as shown in

Table 4.1-2. They are either slow-speed, two-stroke engines or medium-speed four-stroke

engines. The slow-speed engines are usually coupled to the ship’s propeller shaft without

reduction gears. In contrast, medium-speed engines are used with reduction gears or are used to

generate electricity for both ship propulsion and auxiliary power. Category 3 marine engines are

generally designed for commercial shipping vessels larger than 2,000 dead-weight tons (dwt). 

Dead-weight tons is a measure of the weight of a ship at maximum cargo load. One unique

feature of slow-speed, two-stroke engines is that they generally use a crosshead piston design. 

An additional linkage is used in the piston-crank assembly to allow for longer stroke. 
Chapter 4: Tier 1 Standards

4-3

Table 4.1-2: General Characteristics of Category 3 Marine Diesel Engines

Engine Type Fuel Type Size Range,

Liters/cyl

Rated Speed

Range, rpm

Stroke/Bore

Ratio

Number of

Cylinders

Power Range, 

Total kW

slow speed

2-stroke

residual 57-2006 54 to 250 2.38 to 4.17 4 to14 1,100 to

103,000

medium speed

4-stroke

residual,

distillate

30 to 290 327 to 750 1.15 to 1l71 5 to 20 1,000 to

18,100

Source: Diesel & Gas Turbine Catalog 20012

Category 3 marine diesel engines are designed for continuous operation, with total annual

operation often exceeding 5,000 hours. These engines are designed to maximize durability and

fuel efficiency, which results in low operating costs. Typical applications for C3 marine engines

include tankers, roll-on roll-off vessels, container vessels, and cruise ships. The majority of

ocean-going vessels use Category 3 engines for propulsion. Great Lakes and Mississippi River

vessels most often use Category 2 propulsion engines, though some of these vessels continue to

use Category 3 propulsion engines. Vessels with Category 3 engines are also used to a lesser

extent in coast-wise service. 

The majority of Category 3 marine diesel engines burn heavy fuel oil, also known as residual

fuel. Residual fuel is make up of the heavier components of crude oil, including contaminants

such as sulfur, that remain after the crude oil has been processed to obtain gasoline, number 2

diesel, kerosene, and other lighter fuels. Vessels with these engines have fuel heaters to raise

fuel temperatures to 100 or 200 C so that the fuel can flow through the fuel system for eventual

combustion in the engine. Prior to entering the combustion chamber, the heated fuel passes

through a filtration system. Filtration systems may be uniquely designed for each vessel, but

generally include a centrifuge to remove excess water and undesirable solids. In addition, vessel

operators must verify proper engine operation through adjustment of engine injection timing each

time they refuel with heavy fuel oil due to the wide range of fuel qualities in the marketplace.

Category 3 engines are significantly different from Category 1 and Category 2 commercial

marine engines in important ways that affect emissions and emission-control technologies. 

Category 3 engine operation is typically characterized by extended operation under cruising

conditions. This high usage rate, combined with the very high power of Category 3 marine

engines, makes fuel costs such a significant factor for these vessels. Category 3 engines therefore

have the lowest brake-specific fuel consumption rates (BSFC) of any internal-combustion engine

(as low as 176 g/kW-hr).3,4 Manufacturers achieve this with very high brake mean-effective

pressures (up to 2,200 kPa) and low mean piston speeds (7 to 9 m/s). These engine parameters

maximize mechanical and propeller efficiencies.5

 Compared with Category 1 or Category 2

engines, these designs for optimum efficiency result in lower power density (power output for a

given engine weight or cylinder displacement). 
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4-4

This operating profile also has an effect on the tradeoff between NOx and PM emissions. 

Maximum engine efficiency typically depends on managing engine and fuel injection parameters

to achieve very high combustion temperatures and pressures, which correspond to maximum

formation of NOx emissions, as described above. These same conditions provide for good

oxidation of any carbonaceous particulate matter remaining in the cylinder after combustion. 

Over the past ten or twenty years, NOx emissions from uncontrolled Category 3 marine engines

have tended to increase with BSFC improvements as engine manufacturers worked to address

ship owners’ desire to reduce operating costs. In response to MARPOL, manufacturers have

reduced NOx emissions and have found they are able to keep the same BSFC whereas they may

have improved BSFC if not designing for NOx control.

4.1.3 Anticipated Technology to Meet Emission Standards

Engine manufacturers are meeting the Tier 1 standards today using a variety of emissioncontrol technologies. Table 4.1-3 summarizes technology being used by manufacturers to meet

these levels. No individual engine relies on all the listed technologies, but manufacturers have

shown that each of the technologies can be used effectively. The most common approach has

been to focus on increased compression ratio, adapted fuel injection, valve timing and different

fuel nozzles to trim NOx emissions. Manufacturers have generally been able to do this with little

or no increase in fuel consumption. 

Table 4.1-3: Summary of NOx Reduction Techniques Used to Meet IMO Standards

Manufacturer In-Engine changes

Wartsila6 Retard injection

Miller cycle valve timing Higher compression ratio Increased turbo efficiency

Higher max cyl pressure Common rail injection

Caterpillar7

 (MaK) Higher compression ratio

Higher cylinder pressure

Higher charge pressure

Flexible injection system

FMC8 Two stage injection

Miller cycle valve timing Greater stroke/bore ratio

Adjustable compression

Two stage turbocharger

Low intake temperature

Yanmar9 Retard injection

Shorter combustion time

Higher compression ratio

Higher boost pressure

Reduced nozzle hole size

Increased number of holes
Chapter 4: Tier 1 Standards

4-5

4.1.4 Description of Technology

4.1.4.1 Combustion Optimization

Several parameters in the combustion chamber of a heavy-duty diesel engine affect its

efficiency and emissions. These engine parameters include fuel injection timing, combustion

chamber geometry, compression ratio, valve timing, turbulence, injection pressure, fuel spray

geometry and rate, peak cylinder temperature and pressure, and charge air temperature and

pressure. Some strategies are not directly related to improving control of NOx emissions, but are

included in this discussion because of their potential to prevent increases in fuel consumption or

HC or PM emissions resulting from NOx-related emission controls

4.1.4.1.1 Fuel Injection Timing and Electronic Control

Advanced timing is typically used for optimum fuel consumption. In advanced timing the

fuel is injected early and mixes substantially before ignition, resulting in very rapid initial

combustion and a sharp spike in cylinder temperatures and correspondingly high NOx emissions. 

Once combustion begins, fuel injection continues while combustion changes to diffusion

burning, in which a relatively constant heat release results in significantly lower burn

temperatures. Retarded timing reduces NOx emissions because the premixed burning phase is

shortened and because cylinder temperature and pressure are lowered. Timing retard, however,

increases HC, PM, and fuel consumption, because the end of injection comes later in the

combustion stroke where the time for extracting energy from fuel combustion is shortened and

the cylinder temperature and pressure are too low for effective oxidation of PM. Timing retard in

combination with other fuel injection upgrades can delay the start of injection without changing

the end of the combustion event.10 This can be accomplished by using increased injection

pressure, optimized nozzle geometry, or rate shaping. Combining technologies in this way

allows for substantial NOx reductions while minimizing the negative impacts on fuel

consumption or HC and PM emissions.

Most Category 3 engines currently use mechanical systems to adjust injection timing. 

Timing is set based on optimal performance and engine durability at the vessel’s cruising speed,

where the ship operates most frequently and combustion pressure and temperature are the

highest. Optimizing fuel injection timing for NOx emissions at points other than cruising speed

is generally impractical unless the engine is electronically controlled or has a simplified

mechanical system which can be adjusted while the engine is in operation. Electronic controls

are being developed and have been implemented on at least one vessel.

4.1.4.1.2 Combustion Chamber Geometry

Parameters within the combustion chamber geometry that yield reduced emissions include

the shape of the chamber and reduced crevice volumes. One manufacturer states, “Cylinder

heads with flat bottoms were found to avoid the danger of deposition of the fuel with its negative

effects on soot emission at low load. Combustion chambers with small dead volumes have a
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4-6

favorable effect on the possible utilization of the air during operation under conditions with low

excess air ratios.”11

Others state that in comparison with a wide, open bowl, the smaller inner diameter bowls are

designed to generate jet/piston interaction that retards the combustion process.12 The slower

burning rate leads to lower NOx. At the end of combustion the piston bowls with smaller

diameter generate a faster burning rate due to a higher turbulence level generated during the

jet/piston interaction and therefore to more efficient soot oxidation. One researcher found also

found that a piston with a wide bowl and raised central hump, along with increased compression

ratio, represents the best compromise with regard to low-load smoke emission, full-load fuel

consumption and NOx emissions.13 

4.1.4.1.3 Compression Ratio

Increasing the compression ratio can lower NOx levels by increasing the density of the intake

air in the combustion chamber. Redesigning the piston crown or increasing the length of the

connecting rod or piston pin-to-crown length could raise the compression ratio.14 There is a limit

to the benefit of higher compression ratios because of increased combustion pressure and the

limits on engine cylinder safety. One manufacturer demonstrated a 35-percent reduction in NOx

emissions without increasing fuel consumption by increasing peak cylinder pressure 10 percent.15

This increase in pressure was achieved with a compression ratio of 17. The authors reported that

a long-stroke engine has the ideal conditions for a compact combustion space—smooth surfaces

and no corners with difficult access for the fuel jet. Such high compression ratios also demand

reduced valve overlap to avoid valve pockets in the piston crown. Reducing valve overlap

increases the residual gas proportion in the combustion space due to the lower scavenging

efficiency. This further reduces NOx emissions by incorporating a degree of internal exhaust gas

recirculation, as described later in this chapter. The boost pressure and therefore the firing

pressure of the engine must be increased to maintain the low exhaust gas temperatures necessary

for reliable operation with heavy oil.

4.1.4.1.4 Valve Timing

Medium-speed four-stroke engines employ valves in their design whereas two-stroke

generally operate with ports. This technology is only relevant for designs with valves. The

efficiency of a diesel engine generally increases with its expansion ratio because more work is

generated by the engine for a given stroke.16 If the intake and exhaust valves are closed during

the compression stroke, the compression ratio is equal to the expansion ratio. Although a high

expansion ratio is desirable, the corresponding compression ratio is limited by material strength

and NOx formation at high pressures and temperatures.

In an engine-design strategy known as the Miller (or Atkinson) cycle, valve timing is planned

to increase the expansion ratio without increasing the compression ratio. In a standard diesel

engine design, the intake valve opens shortly before the piston reaches top dead center and stays

open until the piston is near bottom dead center. This allows the most time to force air into the
Chapter 4: Tier 1 Standards

4-7

cylinder, which helps maximize volumetric efficiency. In a Miller cycle engine, the intake valve

is kept open well beyond bottom dead center. This reduces the amount of pressure generated

during the compression stroke, thereby allowing a greater expansion ratio. Enhanced

turbocharging or supercharging is required to offset the resulting loss in volumetric efficiency, 

Several engine manufacturers are using a “semi-Miller cycle” to reduce fuel consumption

and emissions from Category 2 and Category 3 propulsion engines by slowing the intake valve

seating and increasing the boost pressure. Coupled with timing retard, one manufacturer reduced

NOx by more than 10 percent while simultaneously reducing fuel consumption by 3 percent.17

This manufacturer reported that slowing the valve seating extended the life of the valve seat. 

Another manufacturer uses intake and exhaust valve timing to reduce pumping losses, which

reduces fuel consumption without increasing NOx emissions in Category 1 and 2 auxiliary

engines.18 A third manufacturer retarded the intake valve closing by 20 degrees and increased the

boost pressure by 7 percent, resulting in a 10-percent reduction in NOx emissions and unchanged

fuel consumption rates.19

4.1.4.1.5 Swirl

Increasing the turbulence of the intake air entering the combustion chamber (i.e., inducing

swirl) can improve the mixing of air and fuel in the combustion chamber. Swirl can be induced

by routing the intake air to achieve a circular motion in the cylinder or by designing piston

geometry for increased turbulence during the compression stroke. Swirl generally has

advantages for reducing PM emissions and improving fuel consumption, but can be used in

combination with other fuel injection strategies for controlling NOx emissions. For example,

combining timing retard or rate shaping strategies to delay the onset of combustion can be done

with minimal negative effects by using swirl to increase the burn rate.20 

4.1.4.2 Improving Charge Air Characteristics

Category 3 engines rely on turbochargers, sometimes in combination with superchargers, to

compress the charge air, improving the power capability of the engine. Cooling the compressed

charge air (aftercooling) increases its density, allowing further improvements in power and fuel

consumption. Aftercooling also lowers NOx emissions by reducing combustion temperatures. 

Manufacturers have already incorporated extensive use of turbocharging and aftercooling. To the

extent that manufacturers can improve aftercooling technologies, this would serve to further

reduce NOx emissions. 

An additional factor related to aftercooling is the water that condenses out of the charge air. 

Depending on the humidity of the ambient air and the amount of aftercooling, this can involve

very large quantities of water. Manufacturers have found ways to divert the water from the

engine for disposal, though this same water may be available for separate use for other emissioncontrol technologies (see section 5.1.2).
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4-8

4.1.4.3 Fuel Injection 

Control of the many variables involved in fuel injection is central to any strategy to reduce

diesel engine emissions. The principal variables being investigated are injection pressure, nozzle

geometry (e.g., number of holes, hole size and shape, and fuel spray angle), the timing of the start

of injection, and the rate of injection throughout the combustion process (e.g., rate shaping). 

Common rail, with a control system that allows for electronic change of injection timing, is also

a useful technology that is currently being used to decrease NOx.

4.1.4.3.1 Fuel Injection Pressure

Particle emissions and fuel consumption generally go down with increasing injection

pressure.21 Increasing the injection intensity, combined with a NOx-neutral increase of

compression ratio and peak pressure, may best balance competing demands for controlling lowload smoke emissions, fuel consumption, and NOx emissions.22

Manufacturers continue to investigate new injector configurations for nozzle geometry and

higher injection pressure (in excess of 2300 bar (34,000 psi)).23,24 Increasing injection pressure

achieves better atomization of the fuel droplets and enhances mixing of the fuel with the intake

air to achieve more complete combustion. Though HC and PM are reduced, higher cylinder

pressures can lead to increased NOx formation.25 However, in conjunction with retarding the

start of fuel injection, higher fuel injection pressures can lead to reduced NOx because of lower

combustion temperatures. HC, PM, or fuel economy penalties from this strategy can be avoided

because the termination of fuel injection need not be delayed. Nozzle geometry is used to

optimize the fuel spray pattern for a given combustion chamber design to improve mixing with

the intake air and to minimize fuel condensation on the combustion chamber surfaces.26

4.1.4.3.2 Nozzle Geometry

Nozzle geometry is a very important parameter for combustion development.27 Injection

duration, droplet sizes and fuel jet momentum are responsible for the quality of the mixture

formation. The nozzle-hole intake is hydro-grinded to optimize the flow. Graphs can be made of

specific fuel consumption (number of holes and effective nozzle flow area) and particle emission

as a function of effective nozzle-flow area. This determines the fuel mass flow rate and therefore

the burning rate and mixture formation. Particle emission and fuel consumption show distinct

minima for slightly different nozzle flow areas. If mixture formation is supported by jet/piston

interaction, nozzle protrusion and spray-elevation angle have to be optimized in relation to the

piston bowl used. This technology, in combination with engine tuning, was used by one engine

manufacturer to achieve IMO levels. The fuel injection nozzles were designed to optimize spray

distribution in the combustion chamber but without compromising on component temperatures

and thereby engine reliability. A graph supplied in the reference paper shows a maximum

reduction of approximately 18% NOx.28
Chapter 4: Tier 1 Standards

4-9

The same manufacturer states their experience with testing of mini-sac nozzles that they had

developed. “Tests have shown that the main source of smoke and soot deposits is the fuel

trapped into the fuel injector sac hole which enters the combustion chamber in an uncontrolled

way during the expansion stroke.” One manufacturer has developed a new “mini-sac hole” fuel

nozzle concept. Test-bed results have shown, as expected, a remarkable reduction of smoke and

hydrocarbon (HC) emissions, slightly better fuel consumption and only a marginal influence on

NOx emissions.”29 Results were 50-70% reduction in HC, 30-50% reduction in smoke with fuel

consumption slightly better (~0.5 g/kWh) and combustion chamber temperatures on the same

level as before. At the time of the paper (CIMAC Congress 2001), such fuel injectors were in

field tests to confirm their reliability.

4.1.4.3.3 Controlling the Timing and Rate of Injection

The most recent advances in fuel injection technology are the systems that use rate shaping or

multiple injections to vary the delivery of fuel over the course of a single injection. Igniting a

small quantity of fuel initially limits the characteristic rapid increase in pressure and temperature

that leads to high levels of NOx formation. Injecting most of the fuel into an established flame

then allows for a steady burn that limits NOx emissions without increasing PM emissions. Rate

shaping may be done either mechanically or electronically. Rate shaping has been shown to

reduce NOx emissions by up to 20 percent.30

For electronically controlled engines, multiple injections may be used to shape the rate of fuel

injection into the combustion chamber. Recent advances in fuel system technology allow highpressure multiple injections to be used to reduce NOx by 50 percent with no significant penalty

in PM. Two or three bursts of fuel can come from a single injector during the injection event. 

The most important variables for achieving maximum emission reductions with optimal fuel

economy using multiple injections are the delay preceding the final pulse and the duration of the

final pulse.31 This strategy is most effective in conjunction with retarded timing, which leads to

reduced NOx emissions without the attendant increase in PM. 

4.1.4.3.4 Common Rail

The main advantages of common rail injection systems and corresponding engine control

system are the flexible injection timing and the high variable injection pressure within the whole

performance map.32 Common rail systems for Category 3 medium speed and low speed engines

are being designed and implemented by at least one of the engine manufacturers for this category. 

MEDIUM SPEED: A common rail system for medium speed engines basically consists of

four components: the pump, the common rail, the injector and the control unit. The pump is used

to fill the common rail with fuel and maintain the pressure at the level requested by the control

unit can vary between 900-1500 bar depending on the optimum for a specific operating point. 

The pump can be either a single pump consisting of several pumping elements driven by the

crankshaft through a gear, or camshaft-driven jerk pumps similar to the conventional injection

pumps. The pumps can be speeded up by employing two or more cam lobes per pump and this
Final Regulatory Support Document

4-10

way the size and number of pumps can be reduced significantly. The accumulator stores the

pressurized fuel. 

A design by one manufacturer has some unique features.33 The common rail pipe is split into

several smaller volumes interconnected with parts with a relatively small flow area rather than

one pipe. The advantages of this include 1) the accumulator volume can be concentrated close to

the injectors, 2) the accumulators can be standardized and easy to manufacture, the accumulator

and one pump serve two cylinders and, 3) the system can be easily shielded and any fuel

leakages collected in a separate drain system. The injector employs servo oil actuation for fuel

injection control rather than direct fuel oil actuation. This is done to lengthen the life of the

solenoid armature which can be affected by high temperatures such as the temperature of heavy

fuel oils (150°C+) This also ensures that the injection will not be affected by erosion wear and

clogging of the small drillings. The design does not have the rail (accumulator) pressure

prevailing at the nozzle seat in between the injection events, mainly to avoid leaking nozzles. 

Otherwise, a large amount of fuel could leak into the cylinder since the non-injection period

represents more than 95% of the total. The injector also has a “rail pressure aided needle

closing” which ensures fast opening of the needle when the pressure in the nozzle is high enough

and equally fast closure of the needle at the end of injection. This ensures combustion control

and smokeless operation. The control unit controls the timing and the quantity of the injected

fuel and controls the refilling and pressure in the accumulators. It also takes care of major safety

functions like pre-circulation, over-pressure protection, pressure evacuation at emergency stop,

etc. Software goes through several iterations in parallel with testing and optimization on the

engine to assure stable software that is easy to configure for various application needs.

LOW SPEED: One common rail system for low speed engines has recently come into the

marketplace and is currently powering a low speed bulk carrier that completed its sea trials in

September 2001. As stated by the manufacturer in the reference material:

The common rail is a manifold running the length of the engine at just below the cylinder cover level. It

provides a certain storage volume for the fuel oil, and has provision for damping pressure waves. The commonrail injection system is fed by heated fuel oil at the usual high pressure (nominally 1000 bar) ready for injection.

The supply unit has a number of high pressure pumps running on multi-lobe cams. The pump design is based

on the proven injection pumps used in the manufacturer’s four-stroke engines. Fuel is delivered from the

common rail through a separate injection control unit for each engine cylinder to the standard fuel injection

valves, which are hydraulically operated in the usual way by the high pressure fuel oil. The control units, using

quick acting rail valves by the engine manufacturer, regulate the timing of fuel injection, control the volume

of fuel injected, and set the shape of the injection pattern. The three fuel injection valves in each cylinder cover

are separately controlled so that they may be programmed to operate separately or in unison as necessary. The

common rail system is built for operation on the grades of heavy fuel oil available today. The key features of

the common rail system are thus: precise volumetric control of fuel injection, with integrated flow-out security,

variable injection rate shaping and free selection of injection pressure, ideally suited for heavy fuel oil, well

proven, high efficiency supply pumps, lower levels of vibration and internal forces and moments, steady

operation at very low running speeds with precise speed regulation and no visible smoke at any operating

speed.34

In addition to fuel injection, the system incorporates exhaust valve actuation and starting air

control. The exhaust valves are operated with hydraulic pushrod, but with the actuating energy

combing from a servo oil rail at 200 bar pressure. “The servo oil is supplied by high pressure
Chapter 4: Tier 1 Standards

4-11

hydraulic pumps incorporated in the supply unit with the fuel supply pumps. The electronically

controlled actuating unit for each cylinder gives full flexibility for valve opening and closing

patterns.”35 

The system is controlled and monitored through the electronic control system developed by

the manufacturer. The modular system has separate microprocessor control units for each

cylinder and overall control and supervision by duplicated microprocessor control units. This

provides the interface for the electronic governor, the shipboard remote control, and the alarm

system. The common rail system replaces some parts such as mechanical injection pumps

(setting the engine is simplified). 

The manufacturer claims that this system may provide selective injection patterns to give

shipowners the option of 20% lower NOx emissions when NOx control is required (fuel

consumption increases) and may be set for fuel economy in areas where NOx control is not

required.

4.1.4.3.5 Electronic-Hydraulic Control of Fuel Injection and Exhaust Valve Actuation

One manufacturer has installed an electronically controlled cam-less engine using an inhouse developed electronic-hydraulic platform on a 37,500 dwt deep sea chemical carrier.36 The

system allows for electronically controlled fuel injection and exhaust valve actuation which

permit individual and continuous adjustment of the timing for each cylinder. Parts that are

removed from the mechanical system include the chain drive for camshaft, camshaft with fuel

cams, exhaust cams and indicator cams, fuel pump actuating gear, including roller guides and

reversing mechanism, conventional fuel injection pumps, exhaust valve actuating gear and roller

guides, engine driven starting air distributor, electronic governor with actuator, regulating shaft,

mechanical, engine driven cylinder lubricators, and engine side control console. The items added

to the engine include a hydraulic power supply, hydraulic cylinder unit with electronic fuel

injection and electronic exhaust valve activation, electronic alpha cylinder lubricator,

electronically controlled starting valve, local control panel, control system with governor, and

condition monitoring system. Two electronic control units are used to control the system with

one being a backup for the first. The manufacturer claims that the electronic version of the

engine was very easy to adjust to the prescribed setting values and was able to keep the very

satisfactory setting values without further adjustments since the vessel’s sea trials in November

2000.

A second manufacturer has further developed their mechanically actuated, electronically

controlled unit injectors and hydraulically actuated, electronically controlled unit injectors to

provide the flexible fuel injection characteristics needed to optimize engine performance and

emissions.37 The manufacturer states that the design approach in both injector concepts is to

utilize a Direct Operated Check (DOC) to precisely control the pressure, timing and delivery of

fuel. The DOC is applicable to electronic unit injector or unit pump configurations with either

mechanical or hydraulic actuation of the pressurizing units. The manufacturer has claimed the

technology eliminates spray distortion and minimizes parasitic losses that may be seen in
Final Regulatory Support Document

4-12

common rail fuel systems. The manufacturer includes a discussion on closed loop NOx control,

stating that ultra-fast NOx sensors are a key part to closed-loop control of NOx emissions. The

sensors provide the benefits of minimized engine to engine variations, minimized cylinder-tocylinder variations and improved transient response with reduced emission and reduced

operational costs. 

4.1.4.4 Lube Oil Consumption

Many of the Category 3 marine diesel engine manufacturers are working to reduce the

consumption of lubricating oil from their engines, to address customer’s demand for reduced

operating costs. Highway diesel engines have greatly reduced HC and PM emissions by

decreasing oil consumption. This is especially relevant for highway engines, because half or

more of uncontrolled PM emissions can be attributed to lubricating oil.

For Category 3 marine engines operating on residual fuel, the high concentration of ash in

residual fuel dominates PM emissions. Therefore, a much smaller percentage of the PM mass

comes from the oil (see Table 4.1-1). Reducing oil consumption in Category 3 marine engines

will decrease PM emissions by a lesser percentage than the same kind of improved oil control in

highway diesel engines. 

4.1.4.5 Emission-Controls and System Approaches

Table 4.1-4 identifies several technologies that individual manufacturers have already

incorporated to reduce emissions and may likely be used to meet the near-term standards. All

these different approaches together would reduce emissions at least 10 or 15 percent below the

near-term standards. The table also identifies several technologies that are beginning to gain

field experience on engines in-use and may be available as the basis for the eventual long-term

standards.
Chapter 4: Tier 1 Standards

4-13

Table 4.1-4: “In-Engine” Combustion Process Changes Currently In-Use or 

Being Investigated by Marine Diesel Engine Design and Manufacturing Companies38

Component or

Operation Changed

Change Parameter Affected SlowSpeed 2-

Stroke

Medium

Speed 4-

Stroke

turbocharger improved efficiency, variable

flow

BSFC, intake pressure Yes Yes

intercooler improved efficiency air inlet temperature Yes Yes

air inlet port redesign shape swirl Maybe Yes

cylinder head redesign shape swirl, compression ratio Maybe Yes

piston crown redesign piston crown shape swirl, compression ratio No Yes

injection pressure increase atomization Yes Yes

injectors redesign low sac, injection rate

shaping

Yes Yes

nozzle hole geometry & number spray pattern changes Possibly Yes

exhaust valve timing “Miller cycle” timing peak cylinder temperature Yes Yes

electronic control replaces mechanical control engine operation, BSFC Yes Yes

common rail injection replace unit injection higher fuel pressure (all

loads)

Yes Yes

injection timing retard and/or vary with load peak cylinder temperature Yes Yes

4.2 Technology Costs

The standards in this rule align with these internationally negotiated standards, so we expect

manufacturers to incur only negligible costs to meet the EPA requirements. These costs will

likely be limited to administrative expenses, such as applying for certification, updating training

manuals, and revising engine labels.

4.3 Emission Reductions

The standards in this rule align with the internationally negotiated MARPOL Annex VI NOx

standards. Engine manufacturers have been manufacturing engines in compliance with these

internationally negotiated NOx standards for the last few years, and we expect that they will

continue to do so. Thus, we do not expect that there will be any emission reductions associated

with this rule. Table 4.3-1 shows the national Category 3 NOx inventories, with and without the

internationally negotiated NOx standards. The no control scenario was developed by taking the

baseline emissions case (compliance with the internationally negotiated NOx limits, as described
Final Regulatory Support Document

4-14

in Chapter 7) and applying to all new vessels the ratio of pre-control emission factors to emission

factors under the internationally negotiated NOx limits.

Table 4.3-1

Category 3 Marine Vessel NOx National Emission Inventories

1996 2010 2020 2030

No control baseline (thousand short tons) 190 303 439 659

EPA /

MARPOL

Annex VI 

(thousand short tons) 190 274 367 531

Percent reduction (relative to no control) — 9.6% 16.2% 19.5%

4.4 Impact on Noise, Energy, and Safety

The Clean Air Act requires that we consider potential impacts on noise, energy, and safety

when establishing the feasibility of emission standards. One important source of noise in diesel

combustion is the sound associated with the combustion event itself. When a premixed charge of

fuel and air ignites, the very rapid combustion leads to a sharp increase in pressure, which is

easily heard and recognized as the characteristic sound of a diesel engine. The conditions that

lead to high noise levels also cause high levels of NOx formation. Fuel injection changes and

other NOx control strategies therefore typically reduce engine noise, sometimes dramatically.

The impact of the new emission standards on energy is measured by the effect on fuel

consumption from complying engines. Many of the marine engine manufacturers are expected to

retard engine timing which, by itself, increases fuel consumption somewhat. Most manufacturers

control NOx emissions by incorporating a combination of engine technologies. Some of these

changes in isolation may increase fuel consumption, but these are generally offset by other

changes that decrease fuel consumption. Moreover, given the fact that we do not expect the

standards in this final rule to change engine technologies, we expect no change in fuel efficiency

to result from the near-term standards.

There are no apparent safety issues associated with the new emission standards. Marine

engine manufacturers have or are currently proving the technologies in the field.

4.5 Category 1 and 2 Marine Engines Greater Than 2.5 Liters/Cylinder

As with Category 3 marine engines, manufacturers are designing their Category 1 and 2

marine engines greater than 130 kW to meet the MARPOL Annex VI NOx limits. 

Manufacturers have met these limits through in-cylinder combustion optimization. In our final

rule for Tier 2 standards for Category 1 and 2 marine engines, we only attributed costs and for

NOx reductions beyond the negotiated international NOx limit (64 FR 73300, December 29,

1999). In the Final Regulatory Impact Analysis for that rule, we discussed in-cylinder emission-
Chapter 4: Tier 1 Standards

4-15

control strategies such as those used by manufacturers today to meet the negotiated international

NOx limit.39
Final Regulatory Support Document

4-16

1. Paro, Daniel, “Development of the Sustainable Engine”, International Council on

Combustion Engines, CIMAC Congress 2001, Docket A-2001-11 Item II-A-13.

2. Diesel & Gas Turbine Worldwide Catalog, 66th Annual Product & Buyer’s Guide for Engine

Power Markets, 2001 Edition, Docket A-2001-11, Item II-A-48 .

3. Gilmer, Johnson, Introduction to Naval Architecture, U.S. Naval Institute, 1992, p. 251.

4. Taylor, C., The Internal Combustion Engine in Theory and Practice, MIT Press, 1990, p. 448.

5. Heywood, J., Internal Combustion Engine Fundamentals, McGraw-Hill, New York, 1988, p.

887.

6. Paro, Daniel, “Development of the Sustainable Engine,” International Council on Combustion

Engines, CIMAC Congress 2001, Docket A-2001-11, Item II-A-13.

7. Schlemmer-Kelling, Udo and Rautenstrauch, Malte, “The New Low-Emission Heavy Fuel Oil

Engines of Caterpillar Motoren,” International Council on Combustion Engines, CIMAC

Congress 2001, Docket A-2001-11, Item II-A-02.

8. Fiedler, Hugo, “Shaping the Combustion Process by Utilisation of High Pressure Injection,”

International Council on Combustion Engines, CIMAC Congress 2001, Docket A-2001-11, Item

II-A-50.

9. Okada,S., Hamaoka, S., Masakawa, S., Takeshita, K., Seki, M., Yoshikawa, S., and

Yonezawa, T., “The Development of Very Low Fuel Consumption Medium Speed Diesel

Engine,” International Council on Combustion Engines, CIMAC Congress 2001, Docket

A-2001-11, Item II-A-04.

10. Okada, S., et. al., “The Development of Very Low Fuel Consumption Medium Speed Diesel

Engine,” International Council on Combustion Engines, CIMAC Congress 2001, Docket

A-2001-11, Item II-A-04.

11. Heider, Guenter and Eilts, Peter of MAN B&W “Improving the Soot-NOx-BSFC Trade-Off

of Medium Speed, 4-Stroke Diesel Engine”, International Council on Combustion Engines,

CIMAC Congress 2001, Docket A-2001-11, Item II-A-05.

12. Philipp, Schneemann, Willmann, Kurreck, “Advanced Optimisation of Common-Rail Diesel

Engine Combustion”, International Council on Combustion Engines, CIMAC Congress 2001,

Docket A-2001-11, Item II-A-03.

13. Heider, G., Eilts, P., “Improving the Soot-NOx-BSFC Trade-Off of Medium Speed, 4-Stroke

Diesel Engine,” International Council on Combustion Engines, CIMAC Congress 2001, Docket

Chapter 4 References
Chapter 4: Tier 1 Standards

4-17

A-2001-11, Item II-A-05.

14. Acurex Environmental Corporation, “Estimated Economic Impact of New Emissions

Standards for Heavy-Duty Highway Engines,” prepared for U.S. EPA, March 26, 1996, Docket

A-2001-11, Item III-B-01.

15. Schlemmer-Kelling, U., Rautenstrauch, M., “The New Low-Emission Heavy Fuel Oil

Engines of Caterpillar Motoren,” International Council on Combustion Engines, CIMAC

Congress 2001, Docket A-2001-11, Item II-A-02.

16. Heider, Guenter and Eilts, Peter of MAN B&W, “Improving the Soot-NOx-BSFC Trade-Off

of Medium Speed, 4-Stroke Diesel Engine”, International Council on Combustion Engines,

CIMAC Congress 2001, Docket A-2001-11, Item II-A-05.

17. Sato, Takeyuki, et. al., “Development of ‘NEO’ Medium Speed Diesel Engines,”

International Council on Combustion Engines, CIMAC, 2001 Congress, Docket A-2001-11, Item

II-A-06.

18. Okada, Shusuke, et. al., “The Development of a Very Low Fuel Consumption Medium

Speed Diesel Engine,” International Council on Combustion Engines, CIMAC, Congress 2001,

Docket A-2001-11, Item II-A-04.

19. Schlemmer-Kelling, U., Rautenstrauch, M., “The New Low-Emission Heavy Fuel Oil

Engines of Caterpillar Motoren,” International Council on Combustion Engines, CIMAC

Congress 2001, Docket A-2001-11, Item II-A-02.

20. Bazari, Z., French, B., “Performance and Emissions Trade-Offs for a HSDI Diesel Engine -

An Optimization Study,” SAE Paper 930592, 1993, Docket A-2001-11, Item II-A-38.

21. Philipp, Schneemann, Willmann, Kurreck, “Advanced Optimisation of Common Rail Diesel

Engine Combustion,” International Council on Combustion Engines, CIMAC Congress 2001,

Docket A-2001-11, Item II-A-03.

22. Heider, G., Eilts, P., “Improving the Soot-NOx-BSFC Trade-Off of Medium Speed, 4-Stroke

Diesel Engine,” International Council on Combustion Engines, CIMAC Congress 2001, Docket

A-2001-11, Item II-A-05.

23. Bazari, Z., French, B., “Performance and Emissions Trade-Offs for a HSDI Diesel Engine -

An Optimization Study,” SAE Paper 930592, 1993, Docket A-2001-11, Item II-A-38.

24. Pierpont, D., Reitz, R., "Effects of Injection Pressure and Nozzle Geometry on DI Diesel

Emissions and Performance," SAE Paper 950604, 1995, Docket A-2001-11, Item II-A-41.

25. Herzog, P., Burgler, L., Winklhofer, E., Zelenda, P., and Carterllieri, W., “NOx Reduction

Strategies for DI Diesel Engines,” SAE Paper 920470, 1992, Docket A-2001-11, Item II-A-46.
Final Regulatory Support Document

4-18

26. Pierpont, D., Reitz, R., “Effects of Injection Pressure and Nozzle Geometry on DI Diesel

Emissions and Performance,” SAE Paper 950604, 1995, Docket A-2001-11, Item II-A-41.

27. Philipp, Schneemann, Willmann, Kurreck, “Advanced Optimisation of Common Rail Diesel

Engine Combustion,” International Council on Combustion Engines, CIMAC Congress 2001,

Docket A-2001-11, Item II-A-03.

28. Aeberli, Kaspar and Mikulicic, Nikola, “The Sulzer RTA-Low Speed Engine Range: Today

and in the Future”, International Council on Combustion Engines, CIMAC Congress 2001,

Docket A-2001-11, Item II-A-07.

29. Aeberli, Kaspar, and Mikulicic, Nikola, “The Sulzer RTA-Low Speed Engine Range: Today

and in the Future”, International Council on Combustion Engines, CIMAC Congress 2001,

Docket A-2001-11, Item II-A-07.

30. Ghaffarpour, M and Baranescu, R, “NOx Reduction Using Injection Rate Shaping and

Intercooling in Diesel Engines,” SAE Paper 960845, 1996, Docket A-2001-11, Item II-A-40.

31. Piepont, D., Montgomery, D., Reitz, R., “Reducing Particulate and NOx Using Multiple

Injections and EGR in a DI Diesel,” SAE Paper 950217, 1995, Docket A-2001-11, II-A-44.

32. Philipp, Schneemann, Wilmann, Kurreck, “Advanced Optimisation of Common Rail Diesel

Engine Combustion,” International Council on Combustion Engines, CIMAC Congress 2001,

Docket A-2001-11, Item II-A-03.

33. Rosgren, Carl-Erik, “Common Rail on Wartsila Four-Stroke Engines”, Marine News No 3-

2001, Wartsila Corporation, pgs 20-23, Docket A-2001-11, Item II-A-36.

34. S. Fankhauser, “World’s First Common-Rail Low-Speed Engine Goes to Sea”, Marine News

No 3-2001, Wartsila Corporation, pgs 12-15, Docket A-2001-11, Item II-A-37.

35. S. Fankhauser, “World’s First common-Rail Low-Speed Engine Goes to Sea”, Marine News

No 3-2001, Wartsila Corporation, pgs 12-15, Docket A-2001-11, Item II-A-37.

36. Sorensen,Per and Pedersen, Peter, “The Intelligent Engine Design Status and Service

Experience”, International Council on Combustion Engines, CIMAC Congress 2001, Docket

A-2001-11, Item II-A-15.

37. Moncelle, M.E., “Fuel Injection System & Control Integration”, International Council on

Combustion Engines, CIMAC Congress 2001, Docket A-2001-11, Item II-A-14.

38. Ingalls, M., Fritz S., “Assessment of Emission Control Technology for EPA Category 3

Commercial Marine Diesel Engines,” Southwest Research Institute, September 2001, Docket

A-2001-11, Item II-A-08.
Chapter 4: Tier 1 Standards

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39. “Final Regulatory Impact Analysis: Control of Emissions from Marine Diesel Engines,”

U.S. Environmental Protection Agency, November 1999, EPA-420-R-99-026, Docket

A-2001-11, IV-A-05.
Final Regulatory Support Document

4-20
Chapter 5: Advanced Emission-Control Technologies

c

 For the purposes of this discussion, the water-to-fuel ratio is expressed in percent. For

example, an engine using 50 percent water would use 50 gallons of water for every 100 gallons

of fuel oil consumed.

5-1

CHAPTER 5: Advanced Emission-Control Technologies

This chapter focuses on technologies under development which could be used to achieve

further emission reductions beyond current standards for Category 3 marine engines. These

technologies will be considered as we develop standards for our future rule. Section 5.1

discusses the introduction of water into the combustion process to reduce emissions. Sections

5.2 and 5.3 discuss selective catalytic reduction and fuel cells. Section 5.4 discusses other engine

technologies that could be used in conjunction with water strategies or SCR.

The discussion in this chapter focuses on Category 3 marine diesel engines. Similar

information about the technology associated with applying these standards to Category 1 and

Category 2 marine diesel engines are contained in the Final Regulatory Impact Analysis for our

1999 rule.1 Section 5.5 briefly discusses those technologies.

Section 5.6 discusses PM emission control from Category 3 marine diesel engines.

5.1 Water Introduction into the Combustion Process

Water can be used in the combustion process to lower maximum combustion temperature,

and therefore lower NOx formation, without increasing in fuel consumption. Water has a high

heat capacity, which allows it to absorb enough of the energy in the cylinder to reduce peak

combustion temperatures. Water may be introduced into the combustion process through

emulsification with the fuel, direct injection into the combustion chamber, or saturating the

intake air. Data on water-based emission-control technologies suggest that this technology has

the potential to reduce NOx emissions by more than 50 percent from the standards we are

finalizing. However, there are several problems with this technology that must be resolved

before it can be applied generally. These issues are discussed below.

5.1.1 Description of the Technology

Water emulsification refers to mixing water with the fuel as a stable suspension. Testing on a

high speed diesel engine has shown a 40 percent reduction in NOx with a water-to-fuel ratio of

50 percentc with only a slight increase in smoke.2 Two power plants with slow-speed diesel

engines are using water emulsification today to reduce NOx.3

 In the referenced case, they are

achieving a 44 percent NOx reduction with 35 percent water emulsification. However, the fuel

consumption was increased by 1 to 2 percent. Although, these were not marine engines, it is

reasonable to expect that similar results would be seen on marine engines that are similar in

design and operation. Water emulsification requires changes to the engine and fuel system. 
Final Regulatory Support Document

5-2

Larger volume fuel injectors and pumps are needed to handle the additional fuel/water volume.

According to a marine engine manufacturer who investigated this technology on its engines,

combining water with fuel in the tank may introduce combustion problems due to unstable

emulsion if more than a 30 percent NOx reduction is targeted.4

 Also, this technique requires a

significantly redesigned fuel handling system to overcome the potential risk of corrosion and to

maintain power output. However, these problems may be overcome in the future as the strategy

is refined.

As an alternative to storing emulsified fuel in the tank, water and fuel can be injected into the

combustion chamber using a common injector. The fuel and water can be mixed just prior to

injection or stratified in the injector. An example of the first strategy was developed for a

medium speed diesel engine, used in a power plant, in which the water is emulsified in the fuel

just prior to injection.5

 The fuel/water is injected using solenoid controlled single injection units. 

Through this system, the fuel/water mix can be changed under different conditions. At low

power (below 30 percent of rated), no water is added, from 30-40 percent of rated power, 20

percent water is added, above 40 percent of rated power, about 35 percent water is added. This

water dosage strategy suggests that the engine may be less tolerant of water in the combustion

chamber at lower loads. Also, the water is shut off for about a minute when the engine load is

increased and the water dosage is significantly decreased prior to shutting off the engine. Using

this strategy, NOx was reduced by 52 percent at intermediate speed and 57 percent at rated speed. 

This report stated that more work would be necessary to construct a durable injection pump that

was eroded by cavitation and water wear after 900 hours. An example of stratified injection was

developed for a slow-speed diesel engine.6

 In this case the injector alternates between fuel and

water. In this application, NOx was reduced 50 percent with about 70 percent water added. By

creating a multi-water layer in the fuel charge, this reduction was achieved without a significant

increase in fuel oil consumption.

More effective control of the water injection process can be achieved through the use of an

independent nozzle for water. Using a separate injector nozzle for the water allows larger

amounts of water to be added to the combustion process because the water is injected

simultaneously with the fuel, and larger injection pumps and nozzles can be used for the water

injection. In addition, the injection timing can be better optimized. On one slow-speed diesel

engine, a 45 percent NOx reduction was achieved with 60 percent water (9 g/kW-hr).7 Further

work on another engine achieved a NOx reduction of 70 percent with 90 percent water (6 g/kWhr).8

 With only 50 percent water, a 40 percent reduction in NOx from this engine was observed. 

Wartsila has installed direct water injection systems on engines in 14 vessels. These are

primarily ferries and ro-ro vessels operating in European waters where there are economic

incentives for reducing NOx emissions. In addition, Wartsila plans to install direct water

injection on engines in another 8 vessels by the end of 2003.9

 A list of these applications is

contained in the appendix following this chapter.

Wartsila is also evaluating two other methods introducing water into the combustion

process.10 These methods are combustion air humidification and steam injection. With

combustion air humidification, a water nozzle is placed in the engine intake and an air heater is
Chapter 5: Advanced Emission-Control Technologies

5-3

used to offset condensation. The result is saturated air at 70-90°C. Initial testing shows that an

80 percent NOx reduction can be achieved with a water-to-fuel ratio of two (4 g/kW-hr). 

Corrosion at this high water-to-fuel ratio is not an issue due to the anti-polishing ring used on

newer engines. With steam injection, waste heat is used to vaporize water which is then injected

into the combustion chamber during the compression stroke. Initial tests have shown an 85

percent NOx reduction with a 3.0-3.5 water-to-fuel ratio (2.4-3.0 g/kW-hr). Fuel consumption

was improved by 2 g/kW-hr (roughly 1 percent). Although higher NOx reductions are seen with

combustion air humidification and steam injection than with direct water injection, more water is

needed for a given NOx reduction, possibly due to the heating of the water prior to introduction

into the cylinder.

5.1.2 Issues to Resolve

Fresh water is necessary for this NOx reduction strategy. Introducing salt water into the

engine could result in serious deterioration due to corrosion and fouling. For this reason, a ship

using water strategies would need to either produce fresh water through the use of a desalination

or distillation system or store fresh water on board. Cruise ships may already have a source of

fresh water that could be used to enable this technology. This water source is the “gray” water,

such as drainage from showers, which could be filtered for use in the engine. For other oceangoing vessels, water storage tanks would likely displace either fuel storage which would limit the

range of the vessel or cargo space which would affect revenues. The alternative of using a

desalination or a distillation unit would include costs for the unit and would also require space

for the unit and for some water storage. Also, when and where a ship operates can have an effect

on the available water. A ship operating in cold weather uses all of the available steam heated by

the exhaust just to heat the fuel. Also, a ship operating in an area with low humidity would not

be able to condense water out of the air using the jacket water aftercooler.

Another concern with the use of water in the combustion process is the effect on PM

emissions. The water in the cylinder reduces NOx, which is formed at high temperatures, by

reducing the temperature in the cylinder during combustion. However, PM oxidation is most

efficient at high temperatures. At this time, we do not have sufficient information on the effect

of water emulsification and injection strategies on PM emissions to quantify this effect.

5.2 Selective Catalytic Reduction

SCR is one of the most effective means of reducing NOx from large diesel engines. This

technology is already being developed for land-based diesel engines and has been used in some

marine demonstration projects. Data suggests that SCR has the potential to reduce NOx

emissions by more than 80 percent from the standards we are finalizing. However, there are still

several problems with this technology that must be resolved before it can be applied generally. 

These issues are discussed below.
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5.2.1 Description of the Technology

In SCR systems, a reducing agent, such urea ((NH2)C2O) is injected into the exhaust. This

urea is mixed into a water solution and injected into the exhaust where the heat decomposes the

urea to produce ammonia and carbon dioxide which is channeled through a reactor where NOx

emissions are reduced. In a system known as “compact SCR”, oxidation catalysts are used in

conjunction with the SCR reactor to increase the effectiveness of the system. An oxidation

catalyst upstream of the SCR reactor can be used to convert NO to NO2. Because the reduction

of NOx can be rate-limited by NO reductions, converting some NO to NO2 allows manufacturers

to use a smaller reactor and/or operate at lower temperatures.11 In addition, oxidation catalysts

can be used downstream of the reactor to oxidize any ammonia that “slips” through the SCR unit. 

SCR systems are being successfully used for many stationary applications, which generally

operate under constant, high-load conditions. In fact, emission reductions in excess of 90 percent

can be achieved using SCR.

Manufacturers are demonstrating similar NOx reduction using SCR technology for marine

applications. The Royal Navy has developed a demonstration system that was tested on a replica

exhaust system for a Type 23 Frigate.12 One vessel with a MaK 8M32 engine (medium-speed

Category 3) has shown reduced NOx emissions by over 90 percent with no fuel consumption

penalty with the SCR system operating.13

Wartsila has demonstrated a standard SCR system on 8 vessels and a compact SCR system,

which uses an oxidation catalyst upstream of the SCR reactor to reduce reactor size, on four

vessels.14,15 Combined, these twelve vessels are equipped with a total of 40 medium-speed

Category 3 marine engines. Also, one manufacturer of SCR systems under the trade name

SINOx, had systems on 56 Category 2 or Category 3 marine engines operating on both residual

and distillate fuel oil at the end of 2000.16 Lists of the systems are contained in the appendix

following this chapter. The majority of these engines were in ferries and ro-ro vessels operating

in European waters where there are economic incentives to use SCR. In addition, these engines

are four-stroke medium-speed engines which have higher exhaust temperatures than two-stroke

low-speed engines which better enables the use of SCR. To prevent sulfur poisoning of the

catalysts, the fuel used by these vessels ranges from 0.1 to 1 percent sulfur.

In one case, SCR was equipped on vessels with two-stroke low-speed engines. More than ten

years ago, MAN B&W worked with California Agencies and Hyundai Heavy Industries to

produce four vessels equipped with SCR.17 The goal of this program was to reduce the emissions

emitted during the transportation of steel to a facility in Pittsburg, California. The first ship was

completed in 1989 and the fourth ship was completed in 1992. Because the vessels were

equipped with low-speed engines (6S50MC, 10,680 hp), the exhaust temperatures were low. In

addition, the vessels operate at low load near the coast; therefore, certain modifications to the

system were necessary. Primarily, the exhaust system was reconfigured to provide the maximum

heat to the reactor which had negative impacts on transient response and efficiency. Also, the

catalyst was formulated to be effective at temperatures as low as 270°C. Because such a reactive

catalyst is vulnerable to sulfur poisoning, the vessels only operate on 0.05 percent sulfur fuel
Chapter 5: Advanced Emission-Control Technologies

5-5

when the SCR unit is active. MAN B&W estimates that these vessels only make about 6 calls to

California per year and that the SCR unit is only active for about 12 hours per call.

Generally, SCR systems available today are effective only above 300°C. To date, these

systems have been applied to four-stroke medium speed engines which have exhaust

temperatures above 300°C at high load. Two-stroke slow speed engines have lower exhaust

temperatures and are discussed later in this section. The effectiveness of the SCR system is

decreased during engine operation at partial loads due to decreased exhaust temperatures. Most

of the engine operation in and near commercial ports and waterways close to shore is likely to be

at these partial loads. In fact, reduced speed zones can be as large as 100 miles for some ports. 

Because of the cubic relationship between ship speed and engine power, engines may operate at

less than 25 percent power in a reduced speed zone. During this low-load operation, little or no

NOx reduction would be expected; SCR would therefore be less effective during low-load

operation near ports. Some additional heat to the SCR unit can be gained by placing the reactor

upstream of the turbocharger; however, this temperature increase would not be large at low loads

and the volume of the reactor would diminish turbocharger response when the engine changes

load. The engine could be calibrated to have higher exhaust temperatures; however, this could

affect durability (depending on the fuel used) if this calibration also increased temperatures at

high loads. For an engine operating on residual fuel, vanadium in the fuel can react with the

valves at higher temperatures and damage the valves.

5.2.2 Issues to Resolve

Low sulfur fuel is necessary to assure the durability of the SCR system because sulfur can

become trapped in the active catalyst sites and reduce the effectiveness of the catalyst. This is

known as sulfur poisoning which can require additional maintenance of the system. SCR units in

service today are operating of fuel ranging from 500 to 10,000 ppmS. Even if these systems can

be made to operate on 15,000 ppmS fuel, an infrastructure would be necessary to ensure that

ships could refuel with 15,000 ppmS fuel at ports they visit. Low sulfur residual fuel is available

in areas which provide incentives for using such fuel, including the Baltic Sea, however such fuel

is not yet available at ports throughout the United States.

 Slow-speed marine engines generally have lower exhaust temperatures than medium speed

engines due to their two-stroke design. However, we are aware of four slow-speed Category 3

marine engines that have been successfully equipped with SCR units. Because of the low

exhaust temperatures, the SCR unit is placed upstream of the turbocharger to expose the catalyst

to the maximum exhaust heat. Also, the catalyst design required to operate at low temperatures

is very sensitive to sulfur. Especially at the lower loads, the catalyst is easily poisoned by

ammonium sulfate that forms due to the sulfur in the fuel. To minimize this poisoning, these

four in-service engines use highway diesel fuel (0.05 percent S). In addition, these ships only

operate with the exhaust routed through the SCR unit when they enter port areas in the U.S.,

which is about 12 hours of operation every 2 months. Therefore, the sulfur loading on the

catalyst is much lower than it would be for a vessel that continuously used the SCR system. To

prevent damage to the catalyst due to water condensation, this system needs to be warmed up and
Final Regulatory Support Document

5-6

cooled down gradually using external heating. Another issue associated with the larger slowspeed engines and lower exhaust temperatures is that a much larger SCR system would be

necessary than for a vessel using a smaller medium-speed engine. Size is an issue because of the

limited space on most ships.

Sulfur in the fuel is also a concern for systems using an oxidation catalyst because, under the

right conditions, sulfur can also be oxidized to form direct sulfate PM. At higher temperatures,

up to 20 percent of the sulfur could be converted to direct sulfate PM in an oxidation catalyst. 

For a typical diesel engine without aftertreatment, the conversion rate is about 2 percent.18

Depending on the precious metals used in the SCR unit, it may convert some sulfur to direct

sulfate PM in the reactor as well. Manufacturers would have to design their exhaust system (and

engine calibration) such that temperatures would be high enough to have good conversion of NO,

but low enough to minimize conversion of sulfur to direct sulfate PM. Direct sulfate PM

emissions could be reduced by using lower sulfur fuel.

SCR systems traditionally have required a significant amount of space on a vessel; in some

cases the SCR unit is as large as the engine itself. However, at least one manufacturer is

developing a compact system with an oxidation catalyst upstream of the reactor to convert some

NO to NO2, thus reducing the reactor size necessary. The reactor size is reduced because the NO2

can be reduced without slowing the reduction of NO. Therefore, the catalytic reaction is faster

because NOx is being reduced through two mechanisms. This compact SCR unit is designed to

fit into the space already used by the silencer in the exhaust system. If designed correctly, this

could also be used to allow the SCR unit to operate effectively at somewhat lower exhaust

temperatures. The oxidation catalyst and engine calibration would need to be optimized to

convert NO to NO2 without significant conversion of sulfur to direct sulfate PM. NOx

reductions of 85 to 95 percent have been demonstrated with an extraordinary sound attenuation

of 25 to 35 dB(A).19

A vessel using a SCR system would also require an additional tank to store ammonia (or urea

to form ammonia). The urea consumption results in increased operating costs. If lower sulfur

diesel fuel were required to ensure the durability of the SCR system or to minimize direct sulfate

PM emissions, this lower sulfur fuel would also increase operating costs. The operation

characteristics of ocean going vessels may interfere with correct maintenance of the SCR system. 

Ferries that use SCR today do not run continuously and therefore any maintenance necessary can

be performed during regular down times. The availability of time for repair can be an issue for

ocean going vessels which often do not have regular down time.

If the combustion is not carefully controlled, some of the ammonia can pass through the

combustion process and be emitted as a pollutant. This is less of an issue for Category 3 marine

engines, which generally operate under steady-state conditions, than for other mobile-source

applications. In addition, in ships where banks of engines are used to drive power generators,

such as cruise ships, the engines generally operate under steady-state conditions near full load. If

ammonia slip still occurred, an oxidation catalyst downstream of the reactor could burn off the

excess ammonia.
Chapter 5: Advanced Emission-Control Technologies

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SCR reactors need constant cleaning using either ultrasound or compressed air. Ultrasound is

performed by the use of an acoustic horn installed in the reactor. The horn automatically sounds

for a period of time periodically during the operation of the engine. The air pulsation from the

horn prevents dirt from building up on the catalyst without requiring engine shut down for

maintenance. The horn may be driven by air from the normal air system installed on the vessel. 

Compressed air cleaning requires a period of engine shut down, during which a soot blowing

probe is inserted into the catalyst unit to remove soot. Inspection holes are opened to allow the

insertion of the probe. It is envisioned that the reactor will be cleaned during each port call,

taking 4 person-hours for medium-speed engines and 6 person-hours for low-speed engines. 

SCR reactors can operate for about 20,000 hours before needing replacement.

5.3 Fuel Cells

Another approach to achieve large reductions in emissions would be to use fuel cells to

power the vessel in place of an internal combustion engine. A fuel cell is like a battery, except a

fuel cell generates electricity instead of storing it. The electro-chemical reaction taking place

between hydrogen and oxygen gases generate the electricity from the fuel cell. The key to the

energy generated in a fuel cell is that the hydrogen-oxygen reaction can be intercepted to capture

small amounts of electricity. The by-product of this reaction is the formation of water. Current

challenges include the storage or formation of hydrogen for use in the fuel cell and cost of the

catalyst used within the fuel cell.

Over the past 5 years, several efforts to apply fuel cells to marine applications have been

conducted. These include grants from the Office of Naval Research and the U.S. Navy. The

Office of Naval Research initiated a three-phase advanced development program to evaluate fuel

cell technology for ship service power requirements for surface combatants in 1997.20 The U.S.

Navy in early 2000 sponsored an effort to continue the development of the molten carbonate fuel

cell for marine use.21 The Society of Naval Architects and Marine Engineers released the

technical report “An Evaluation of Fuel Cells for Commercial Ship Applications.”22 This report

examines fuel cells for application in commercial ships of all types for electricity generation for

ship services and for propulsion. 

The concept of fuel cells is currently supported by several sources, including the U.S.

Maritime Administration (MARAD) and the state of California’s Fuel Cell Partnership. 

MARAD’s Division of Advanced Technology has included the topic of fuel cells as a lowemission technology that should be demonstrated. California’s Fuel Cell Partnership seeks to

achieve four main goals which include 1) demonstrate vehicle technology by operating and

testing the vehicles under real-world conditions in California; 2) demonstrate the viability of

alternative fuel infrastructure technology, including hydrogen and methanol stations; 3) explore

the path to commercialization, from identifying potential problems to developing solutions; and

4) increase public awareness and enhance opinion about fuel cell electric vehicles, preparing the

market for commercialization.
Final Regulatory Support Document

5-8

5.4 Other Engine Technologies

Chapter 4 discusses several in-cylinder technologies that are being used to meet levels the

internationally negotiated NOx standards. These technologies can be used in conjunction with

water introduction strategies or selective catalytic reduction to optimize the engine/exhaust

systems for further reductions. This section describes two other in-cylinder control strategies that

could be used in conjunction with advanced technology for further emission reduction: exhaust

gas recirculation and electronic control.

5.4.1 Exhaust Gas Recirculation

Exhaust gas recirculation (EGR) is a recent development in diesel engine control technology

for obtaining significant NOx reductions. EGR reduces peak combustion chamber temperatures

by slowing reaction rates and absorbing some of the heat generated from combustion. While

NOx emissions are reduced, PM and fuel consumption can be increased, especially at high loads,

because of the reduced oxygen available and longer burn times during combustion.23,24

There are several methods of controlling any increase in PM emissions attributed to EGR. 

One method of minimizing PM increases is to reduce the flow of recirculated gases during highload operation, which would also prevent a loss in total power output from the engine. Recent

experimental work on a four-stroke high-speed diesel engine showed NOx reductions of about 50

percent, with little impact on PM emissions, using just six percent EGR in conjunction with a

strategy of multiple injections.25 Another method is to cool the exhaust gas recirculated to the

intake manifold. By cooling the recirculated gas, it takes up less volume allowing more room for

fresh intake air. With EGR cooling, a much higher amount of exhaust gas can be added to the

intake charge. At light loads, there can be a small NOx penalty due to increased ignition delay,

but at high loads, some additional NOx reduction may result from EGR cooling.26 A third

method to offset the negative impacts of EGR on PM is through the use of high intake air boost

pressures. By turbocharging the intake air, exhaust gas can be added to the charge without

reducing the supply of fresh air into the cylinder.27

Exhaust gas recirculation has also been shown on a slow-speed two-stroke engine, in

conjunction with direct water injection, to achieve a 70 percent reduction in NOx.28 Without

EGR, only a 50 percent reduction in NOx was achieved. In a separate engine, six percent EGR

dilution with a slow-speed two-stroke engine reduced NOx emissions by 22 percent.29 In these

cases, internal EGR was used by decreasing the efficiency of the scavenging process and trapping

additional exhaust gas in the cylinder. The use of internal EGR has two primary advantages. 

First, the benefits of EGR can be achieved without any additional hardware such as lines and

valves, thereby reducing the costs and complexity of the system. Second, internal EGR avoids

some problems associated with external EGR. For example, routing the exhaust gas into the

intake stream could cause soot to form deposits in the intake system, leading to wear on the

turbocharger or a decrease in the efficiency of the aftercooler. As the amount of soot in the

cylinder increases, so does the amount of soot that works its way past the piston rings into the

lubricating oil, which can lead to increased engine wear. Another concern with routing the
Chapter 5: Advanced Emission-Control Technologies

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exhaust into the intake stream, especially for engines operating on residual fuel, would be

corrosion in the intake system if the sulfur in the exhaust gas were to condense and form sulfuric

acid. Using internal EGR avoids these problems.

5.4.2 Electronic Control

Various electronic control systems are in use or under development for nonroad, locomotive,

highway, and marine diesel engines. Use of electronic controls enables designers to implement

much more precise control of the fuel injection system and is especially beneficial for advanced

concepts such as rate shaping. Through this precise control, trade-offs between various control

strategies can be better balanced to minimize any negative effects. In addition, electronic

controls can be used to sense ambient conditions and engine operation to maximize performance

and minimize emissions over a wide range of conditions, such as transient operation of the

engine. It can also be used with a feedback loop to optimize the exhaust conditions for effective

selective catalytic reduction of NOx. Electronic control is already used in limited marine

applications.

5.5 Category 1 and Category 2 Marine Diesel Engines

We also intend to reconsider Tier 3 emission standards for Category 1 and Category 2

standards in a future rulemaking. We proposed Tier 3 standards for these engines on December

11, 1998 (63 FR 68508), but chose not to finalize the Tier 3 standards at that time. Further

analysis of potential Tier 3 standards for Category 1 and Category 2 marine diesel engines may

be found in the draft Regulatory Impact Analysis prepared for the proposal for our 1999 rule.30

Those standards relied on the types of in-cylinder controls described in 5.1 above.

In determining the proposed Tier 3 standards for Category 1 and Category 2 marine engines,

we considered the application of technology being used for land-based nonroad and locomotive

engines to marinized engines. We recently published a report on technology that we believe can

be used by nonroad engines to meet Tier 3 standards.31,32 We will consider the application of this

technology to marinized engines as well. We will also consider the feasibility of using more

advanced technologies than in-cylinder control for Category 1 and Category 2 marine engines. 

For instance, water-injection and SCR may also be applied to these engines.

5.6 PM Emission Control from Category 3 Marine Diesel Engines

For typical diesel engines operating on distillate fuel, particulate matter formation is

primarily the result of incomplete combustion of the fuel (and lube oil). The traditional incylinder technologies discussed in section 4.1.4 can be used to reduce this type of PM formation

while simultaneously reducing NOx emissions. If aftertreatment, such as SCR, is used to control

NOx, then the in-cylinder technologies can be used primarily for PM reductions. However,

because Category 3 marine engines generally use high-sulfur residual fuel, two issues arise.
Final Regulatory Support Document

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The first issue is that the majority of PM emissions in engines burning residual fuel comes

directly from the high concentration of sulfur in the fuel. As discussed in Chapter 4, metal

oxides and sulfur in the fuel can make up 65 percent of the PM in the exhaust compared with

only 15 percent in highway diesel engines. The emission-control technology discussed above

would only have an impact on the non-sulfur PM exhaust emissions. A more effective control

strategy would be to reduce the amount of sulfur in the fuel used by Category 3 marine engines. 

In addition, engines calibrated and tested for PM on distillate fuel would not necessarily see the

same reduction in PM when operated on residual fuel due to the differences in the fuel

characteristics. This leads to the second issue.

The second issue is that no acceptable procedure exists for measuring PM from engines

operating on fuels with a sulfur level greater than 0.8 percent, as specified by ISO 8178. This is

supported by correlation testing performed on a Category 3 engine at four laboratories.33

Residual fuels typically have sulfur levels on the order of 2-4 percent and even distillate fuels

used by Category 3 marine diesel engines generally have sulfur levels over 1 percent. 

Established PM test methods collect PM on a filter with a specification for maximum

temperature. This maximum temperature is intended to ensure that the soluble organic fraction

of the PM will condense and be collected on the filter. While non-sulfate PM is made up of

hydrocarbons from the fuel and lube oil, the direct sulfate portion of the PM is made up of sulfate

ions bonded with water. As a result, the measured mass of the sulfate portion of the PM is

sensitive to test conditions such as temperature and humidity. This causes unacceptable

variability in PM test results from engines operating on high sulfur fuels. In addition, when

testing on residual fuel, the particulate concentration can ten times higher than when testing on

distillate fuel. At these high PM levels, the PM in the exhaust can unpredictably deposit on the

walls of the dilution tunnel and re-entrain into the exhaust stream. This adds some further

uncertainty to the measured results.
5-11

Appendix to Chapter 5: Current DWI and SCR Installations

Wartsila DWI Reference List 2001 34

Ship Owner Engine In Service

Ro ro Goby Shipping AB 12V46C Jan 1999

Ro ro Goby Shipping AB 12V46C Feb 1999

Ro ro Ernst Russ GmbH & Co 12V46C Mar 1999

Ro ro Ernst Russ GmbH & Co 12V46C Apr 1999

Ro ro Bror Husell Chartering AB Ltd 16V46B May 1999

Ro ro Ernst Russ GmbH & Co 16V46B Jun 1999

Ro ro Ernst Russ GmbH & Co 16V46B Dec 1999

Silja Symphony Silja Line 4x9L46A Jun 1999

Silja Serenade Silja Line 4x9L46A Jun 1999

Finnmarken OVDS, Norway 2xW6L32, 2xW9L32 Nov 2001

Trolfjord TFDF, Norway 2xW9L32 End 2001

Superfast XI Superfast Ferries 4x12V46 End 2001

Superfast XII Superfast Ferries 4x12V46 Spring 2002

Coral Princess P&O Princess Cruises 2x16V46 Sep 2002

Island Princess P&O Princess Cruises 2x16V46 Sep 2002

Diamond Princess P&O Princess Cruises 2xW846, 2xW9L46 Jul 2003

Saphire Princess P&O Princess Cruises 2xW846, 2xW9L46 End 2003

Chrystal Serenity NYK Line 6x12V38B Apr 2002

Chemical Tanker Fortum Oil and Gas Oy 9L46C May 2003

Chemical Tanker Fortum Oil and Gas Oy 9L46C July 2003

Car Ferry TFDF, Norway 2xW9L32 End 2003

Chemical Tanker Fortum Oil and Gas Oy 8L46 Jan 2003

Chemical Tanker Fortum Oil and Gas Oy 8L46 July 2003
Final Regulatory Support Document

5-12

Wartsila SCR Reference List 2001 35

Vessel Application Engines Fuel Reduction

Agent

Delivery

Date

Notes

Aurora af

Helsingborg

Double

ended ferry

1 x WV6R32 MDO

0.1%S

40% urea

water

1992

Silja

Serenade

Cruise ferry 1 x WV8R32 HFO

0.5%S

40% urea

water

1995

Silja

Symphony

Cruise ferry 1 x WV8R32 HFO

0.5%S

40% urea

water

1995

Gabriella Cruise ferry 1 x WV6R32 HFO

0.5%S

40% urea

water

1997 Retrofit

Thjelvar Ferry 2 x WV4R32

4 x WV12R32

HFO

0.5%S

40% urea

water

1997 Compact

SCR, retrofit

Birka

Princess

Cruise ferry 4 x WV12R32

2 x WV6R32

1 x WV4R32

HFO

0.5%S

40% urea

water

1999 Compact

SCR, retrofit

M/V

Spaarneborg

Ro-Ro 1 x 7RTA52U

2 x W6L20

HFO

MDO

40% urea

water

1999

M/V

Schieborg

Ro-Ro 1 x 7RTA52U

2 x W6L20

HFO

MDO

40% urea

water

1999

M/V

Slingeborg

Ro-Ro 1 x 7RTA52U

2 x W6L20

HFO

MDO

40% urea

water

2000

Gotland

Rederi

RoPax 4 x 12V46

3 x 9L20

HFO

<1%S

40% urea

water

2000 Compact

SCR

Gotland

Rederi

RoPax 4 x 12V46

3 x 9L20

HFO

<1%S

40% urea

water

2000 Compact

SCR

M/V Granö Ro-Ro 1 x WV1632 HFO 40% urea

water

2000 Compact

SCR, retrofit

Newbuilding Special 2 x W6L32

2 x W12V32

LFO 40% urea

water

2002 Compact

SCR
Chapter 5: Advanced Emission-Control Technologies

5-13

SIEMENS SINOx Marine Exhaust Gas Treatment Plants and Systems36,37

Customer

Operator

Field of

Application Fuel

Capacity 

in kW

Volume

flow in

Nm3

/h

Extent of

Delivery

Delivery

Date

TT-Line(D)

Nils Dacke

Ship propulsion MDO 4,500 27,500 SINOx 1995

Hertug Skule(N) 

Fosen Trafikklag

Ship propulsion MDO 920 7,200 SINOx 1997

Gabriella (SF) 

Viking Line

Ship genset MDO 2,000 12,000 SINOx 1997

Thielvar (S)

Gotland Rederi

Ship propulsion

4 main engines

2 aux engines

MDO 4x3,720

2x1,240

4x18,500

2x6,000

SINOx 1997

Visby(S) Gotland

Rederi

Ship propulsion

4 main engines

3 aux engines

MDO 4x5,200

3x1,435

4x37,500

3x7,500

SINOx 1997

Fast Ferry(S)

Gotland Rederi

Ship propulsion

4 main engines

3 aux engines

MDO 4x7,000

3x450

4x40,000 SINOx 1998

MS Cellus (S)

Roerd Braren

Ship propulsion

1 main engine

1 aux engine

HFO

MDO

3,840

540

21,000

3,000

SINOx 1998

Birka Princess

Wartsila NSD

Ship propulsion

4 main engines

2 aux engine

HFO

MDO

4x4,500

2x2,250

4x26,000

2x14,200

SINOx 1998

MS Ortviken(S)

SEA PARTNER

Ship propulsion

2 x main engines

3 x aux engines

HFO

MDO

2x4,050

3x610

2x25,500

3x3,200

SINOx 1999

MS Baltic 2 Ship propulsion

1 main engine

HFO 3,360 19,000 SINOx 1999

MS Baltic 3 Ship propulsion

1 main engine

HFO 3,360 19,000 SINOx 1999

MS Baltic 4 Ship propulsion

1 main engine

HFO 3,360 19,000 SINOx 1999

MS Timbus(S)

Roerd Braren

Ship propulsion

1 main engine

1 aux engines

HFO

MDO

3,840

540

21,000

3,000

SINOx 1999

Customer

Operator

Field of

Application

Fuel Capacity in

kW

Volume

flow in

Nm3/h

Extent of

Delivery

Delivery

Date
Final Regulatory Support Document

Customer

Operator

Field of

Application Fuel

Capacity 

in kW

Volume

flow in

Nm3/h

Extent of

Delivery

Delivery

Date

5-14

MS Forester(S)

Roerd Braren

Ship propulsion

1 main engine

2 aux engines

HFO

MDO

3,840

2x239

21.000

2x1,200

SINOx 1999

Silja Line Ship propulsion

4 main engines

HFO 4 x 7,950 48,500 SINOx 2000

1600 LM

RoPax(S)

Gotland Rederi

Ship propulsion

4 main engines

3 auxillary engines

HFO 4x12,600

3x1,530

4 x 63,000

3 x 9,000

SINOx 2000
Chapter 5: Advanced Emission-Control Technologies

5-15

1. Final Regulatory Impact Analysis: Control of Emissions from Marine Diesel Engines,

November 1999. EPA420-R-99-026. Docket A-2001-11, Item IV-A-05.

2. Konno, M., Chikahisa, T., Murayama, T., “Reduction of Smoke and NOx by Strong

Turbulence Generated During the Combustion Process in D.I. Diesel Engines,” SAE Paper

920467, 1992, Docket A-2001-11, Item IV-A-07.

3. Ohtsu, M., “Recent Development of Slow Speed Diesel Power Plants,” International Council

on Combustion Engines, CIMAC Congress 2001, Docket A-2001-11, Item IV-A-09.

4. Paro, D., “Effective, Evolving, and Envisaged Emission Control Technologies for Marine

Propulsion Engines,” presentation from Wartsila to EPA on September 6, 2001, Docket

A-2001-11, II-A-72.

5. Kamleitner, E., Haury, H., “Reduction of Emissions of a High Efficient Diesel Engine with

Solenoid Controlled Injection Pump by Means of Water Injection,” International Council on

Combustion Engines, CIMAC Congress 2001, Docket A-2001-11, Item IV-A-10.

6. Sakabe, H., Okabe, M., “The UEC-LS II/LSE Engine Development Program,” International

Council on Combustion Engines, CIMAC Congress 2001, Docket A-2001-11, Item IV-A-08.

7. Aeberli, K., Mikulicic, N., “The Sulzer RTA-Low Speed Engine Range: Today and In the

Future,” International Council on Combustion Engines, CIMAC Congress 2001, Docket

A-2000-11, Document II-A-07.

8. Paro, D., “Effective, Evolving, and Envisaged Emission Control Technologies for Marine

Propulsion Engines,” presentation from Wartsila to EPA on September 6, 2001, Docket

A-2001-11, II-A-72.

9. E-mail from Fred Danska of Wartsila to Cheryl Caffrey of EPA on April 22, 2002, Docket

A-2001-11, Document IV-A-12.

10. Paro, D., “Effective, Evolving, and Envisaged Emission Control Technologies for Marine

Propulsion Engines,” presentation from Wartsila to EPA on September 6, 2001, Docket

A-2001-11, II-A-72.

11. Schafer-Sindlinger, A., “NOx Reduction for Diesel Vehicles,” Degussa, Presentation at

Corning’s Clean Diesel Workshop, September, 1999, Docket A-2001-11, Item II-A-29.

12. Hughes, D., McAdams, R., Non-Thermal Plasma for Marine Diesel Engines,” International

Council on Combustion Engines, CIMAC Congress 2001, Docket A-2001-11, Document

IV-A-13.

Chapter 5 References
Final Regulatory Support Document

5-16

13. Ingalls, M., Fritz S., “Assessment of Emission Control Technology for EPA Category 3

Commercial Marine Diesel Engines,” Southwest Research Institute, September 2001, Docket

A-2000-11, Document II-A-08.

14. E-mail from Fred Danska of Wartsila to Cheryl Caffrey of EPA on April 22, 2002, Docket

A-2001-11, Document IV-A-12.

15. Mikulicic, N., “Exhaust Emissions: Next Steps for Low-Speed Two-Stroke Engines,” article

in Marine News, published by Wartsila NSD, N0. 3 -1999, Docket A-2001-11, Document

II-A-01.

16. Ingalls, M., Fritz S., “Assessment of Emission Control Technology for EPA Category 3

Commercial Marine Diesel Engines,” Southwest Research Institute, September 2001, Docket

A-2000-11, Document II-A-08.

17. MAN B&W, “Emission Control Two-Stroke Low-Speed Diesel Engines,” Docket

A-2001-11, Document IV-A-14.

18. “Emission Factors for Compression Ignition Nonroad Engines Operated on No. 2 Highway

and Nonroad Diesel Fuel,” U.S. Environmental Protection Agency, EPA420-R-98-001, March

1998, Docket A-2001-11, II-A-49.

19. Paro, D., “Effective, Evolving, and Envisaged Emission Control Technologies for Marine

Propulsion Engines,” presentation from Wartsila to EPA on September 6, 2001, Docket

A-2001-11, II-A-72.

20. Steinfeld, G., Sanderson, R., Ghezel-Ayah, H., and Abens, S., “Direct Carbonate Fuel Cell

for Ship Service Application”, Energy Research Corporation, Danbury CT, Docket A-2001-11,

Item II-A-33.

21. Karni, Z., Fontneau, P., Allen, S., Sedat, R., Ghezel-Ayagh, H., Abens, S., Sanderson, R.,

Steinfeld, G., Lukas, M., “Marine Application of Fuel Cells”, www.ercc.com/marine_app.pdf,

January 10, 2002, Docket A-2001-11, Item II-A-34.

22. The Society of Naval Architects and Marine Engineers, “Fuel Cells for Commercial Ships”,

www.sname.org/tr_press_fuel.htm, January 10, 2002, Docket A-2001-11, Item II-A-35.

23. Herzog, P., Burgler, L., Winklhofer, E., Zelenda, P., and Carterllieri, W., “NOx Reduction

Strategies for DI Diesel Engines,” SAE Paper 920470, 1992, Docket A-2001-11, Item II-A-46.

24. Piedpont, D., Montgomery, D., Reitz, R., “Reducing Particulate and NOx Using Multiple

Injections and EGR in a DI Diesel,” SAE Paper 950217, 1995, Docket A-2001-11, Item II-A-46.

25. Montgomery, D. and Reitz, R., “Six-Mode Cycle Evaluation of the Effect of EGR and

Multiple Injections on Particulate and NOx Emissions from a D.I. Diesel Engine,” SAE Paper

960316, 1996, Docket A-2001-11, Item II-A-43.
Chapter 5: Advanced Emission-Control Technologies

5-17

26. Herzog, P., Burgler, L., Winklhofer, E., Zelenda, P., and Carterllieri, W., “NOx Reduction

Strategies for DI Diesel Engines,” SAE Paper 920470, 1992, Docket A-2001-11, Item II-A-46.

27. Uchida, N., Daisho, Y., Saito, T., Sugano, H., "Combined Effects of EGR and Supercharging

on Diesel Combustion and Emissions," SAE Paper 930601, 1993, Docket A-2001-11, Item

II-A-42.

28. Aeberli, Kaspar, et. al., “The Sulzer RTA-Low Speed Engine Range: Today and in the

Future,” International Council on Combustion Engines, CIMAC Congress 2001, Docket

A-2001-11, Item II-A-07.

29. Mikulicic, N. “Exhaust Emissions: Next Steps for Low-speed Two-stroke Engines,” Marine

News, 1999, No. 3, Docket A-2001-11, II-A-01.

30. Draft Regulatory Impact Analysis: Control of Emissions from Marine Diesel Engines,

November 1998. EPA420-R-98-017. Docket A-2001-11, Item IV-A-06.

31. “Nonroad Diesel Emission Standards; Staff Technical Paper,” U.S. Environmental

Protection Agency, EPA420-R-01-052, October 2001, Docket A-2001-11, IV-A-03.

32. Memorandum from Chet France, Director ASD to Margo Tsirigotis Oge, Director OTAQ,

“Comments on Nonroad Diesel Emissions Standards Staff Technical Paper,” June 4, 2002,

Docket A-2001-11, IV-A-02.

33. Bastenhof, D., “Exhaust Gas Emission Measurements; A Contribution to a Realistic

Approach,” CIMAC, May 1995.

34. E-mail from Fred Danska of Wartsila to Cheryl Caffrey of EPA on April 22, 2002.

35. E-mail from Fred Danska of Wartsila to Cheryl Caffrey of EPA on April 22, 2002.

36. SINOx Exhaust Gas Treatment Plants and Systems, Marine, Sales brochure from Siemens

Westinghouse Power Corp.

37. Ingalls, M., Fritz S., “Assessment of Emission Control Technology for EPA Category 3

Commercial Marine Diesel Engines,” Southwest Research Institute, September 2001, Docket

A-2000-11, Document II-A-08.
Final Regulatory Support Document

5-18
Chapter 6: Estimated Costs for Advanced Technologies

6-1

CHAPTER 6: Estimated Costs for Advanced Technologies

This chapter presents estimated costs for several of the emission-control technologies

described in Chapter 5 for reducing emissions below the levels necessary to meet this first tier of

EPA emission standards. While the technologies can be applied generally to marine diesel

engines, we analyze the costs of these technologies only for engines over 30 liters per cylinder.

These estimated costs are based on our current understanding of the changes necessary to

incorporate the advanced technologies on marine diesel engines. We start with a general

description of the approach for estimating costs, then describe the various technologies and

assess the projected costs of each approach. We developed the costs for individual technologies

in cooperation with ICF, Incorporated and A.D. Little.1

 When we propose emission standards in

the future, we will revisit the cost estimates presented in this chapter. We intend to use any

information that becomes available in the meantime to update the cost estimates as needed to

most accurately project the anticipated economic impacts of the standards we eventually propose.

6.1 Methodology

To simplify the analyses, costs were examined for one medium-speed engine and one slowspeed engine. Each of these base engines is considered in three different cylinder configurations

to cover a wider range of power ratings. While these engines are drawn from real product

offerings, they are intended to represent a broader group of engines than just these two models. 

Table 6.1-1 highlights the key operating characteristics of these representative engines. 

Costs of control include variable costs (for incremental hardware and assembly) and fixed

costs (for tooling and R&D). For technologies sold by a supplier to the engine manufacturers,

variable costs are marked up at a rate of 29 percent to account for the supplier's overhead and

profit.2

 The analysis also includes consideration of operating costs where that would apply. The

result is a total estimated incremental cost for individual engines of various sizes. Costs are

presented in 2002 dollars.

The impact of fixed costs on the per-engine costs depends on the number of engines produced

using the advanced technologies. We consider two cost scenarios: applying the advanced

technologies only to Category 3 engines on U.S. vessels, and applying them to Category 3

engines on all vessels that use U.S. ports.
Final Regulatory Support Document

6-2

Table 6.1-1

Power Ranges and Nominal Power for Estimating Costs (kW)

Specific Displacement

(L/cyl)

Maximum engine

speed (rpm)

Number of

Cylinders

Rated Power (kW)

55 600 6 4,000

9 6,000

12 8,000

900 80 4 8,000

8 16,000

12 24,000

6.2 Technology Costs

Total estimated costs are developed by considering the development time and hardware costs

to design and integrate emission-control strategies into a marketable engine. The following

paragraphs describe these technologies and their application to marine engines.

6.2.1 Fuel Injection Improvements

Fuel-injection improvements can be made in at least two ways. First, manufacturers might

redesign existing systems for higher pressure, better control (including rate shaping), and

adjusted injection timing. Other manufacturers may make a design decision to make a step

change in technology, switching to common rail systems. Second, common rail technology

allows the engine designer to maintain high-pressure injection at all engine speeds and makes it

easier to control injection timing, including the ability to manage split injection. Common rail

systems depend on incorporating electronic controls to manage fuel delivery. 

Table 6.2-1 details the variable costs associated with a common-rail system, including

estimated costs for the various controllers, pumps, and other necessary hardware. Total variable

costs range from $11,000 to $22,000 for medium-speed engines and from $24,000 to $71,000 for

slow-speed engines. These costs would be the same whether the standards apply to engines on

U.S. vessels or whether they also apply to engines on foreign vessels. Fixed costs for

development and tooling are considered in the next section. 
Chapter 6: Estimated Costs for Advanced Technologies

6-3

Table 6.2-1

Projected Costs per Engine for Fuel Injection Upgrade

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

Hardware cost to manufacturer

 electronic control unit $350 $350 $350 $350 $350 $350

 common rail accumulator $2,000 $3,000 $4,000 $4,000 $8,000 $12,000

 low-pressure pump $1,600 $2,400 $3,200 $3,200 $6,400 $9,600

 high-pressure pump $3,200 $4,800 $6,400 $6,400 $12,800 $19,200

 modified injectors $2,100 $3,150 $4,200 $7,200 $14,400 $21,600

 wiring harness $300 $300 $300 $600 $600 $600

Total component cost $9,550 $14,000 $18,450 $21,750 $42,550 $63,350

Assembly @ $28/hr $1,882 $2,822 $3,763 $2,509 $5,018 $7,526

Total Hardware cost $11,432 $16,822 $22,213 $24,259 $47,568 $70,876

6.2.2 Engine Modifications

Engine modifications may include a wide range of strategies to improve the way an engine

handles air intake, fuel injection, or air-fuel mixing in the cylinder. Several different strategies

may work together to provide an optimum level of emission control while minimizing any

potential negative effects on performance, durability, or fuel consumption. 

The kind of changes addressed in this section do not necessarily involve variable costs

(except for changes to fuel injection, as noted above). Changing valve timing and redesigning

the geometry of engine components, for example, would generally not involve cost increases

beyond those considered for development time and tooling. Projected costs in this section

include the fixed costs associated with the fuel-injection improvements described above. Since

fuel-injection variables must be incorporated in the context of other changes to the engine, it is

appropriate to consider development time for fuel injection together with the overall R&D effort

for each engine model. 

The estimated costs include a substantial time allowance for manufacturers to pursue engine

improvements. This would allow for further exploration beyond fuel-injection variables into

many of the strategies described in Chapter 5. Manufacturers could use this development time to

pursue changes in valve timing, compression ratio, location of fuel injectors, piston head

geometry, and many other design variables. The cost projections generally contemplate

development time (including testing) for two engineers and three technicians to work on each

engine family for a full year. This development effort would apply for all the different available
Final Regulatory Support Document

6-4

cylinder configurations of a given engine family, which is consistent with our provision allowing

manufacturers to certify their engine families based on single-cylinder development engines. In

practice, manufacturers would likely need more time to redesign the first engine family, while the

lessons learned from early development efforts would lead to reduced development time for later

engine families. 

An important variable in estimating fixed costs on a per-engine basis is identifying the

appropriate sales volumes. Sales volumes for U.S. vessels are very small. For this analysis we

have estimated that manufacturers will be able to amortize fixed costs related to the emission

standards over four engines per year. This is somewhat higher than current sales volumes, for

two main reasons. First, even if the standards were to apply only to Category 3 engines on U.S.

vessels, manufacturers may be able to market these engines on the global market as a superior

product, thereby increasing the sales volume over which they can recover development costs. 

Second, it is possible that new ship construction for the U.S. market may increase in the future. 

Currently, new ship construction rates in the U.S. are below the rate necessary for ongoing

replacement of vessels, resulting in an overall aging of the U.S. fleet. Requirements related to

double-hull tanker designs may also lead ship owners to consider retrofitting or replacing

existing ships. Together, these factors may lead to increased rates of ship construction over the

next several years. Costs are amortized over five years, consistent with previous cost estimates

for emission-control programs.

Amortizing fixed costs would involve a very different set of numbers if the standards apply to

engines on foreign vessels. Under this scenario, we would estimate annual sales of 40 engines

for each engine family. This comes from dividing the approximately 1200 total engines

produced world-wide by half (to exclude those that will never come to the U.S.), and dividing the

remaining engines over five companies, each with an average of three separate engine families. 

Setting international standards that apply globally would roughly double the assumed sales

volumes and halve the estimated fixed cost per engine, but this would be a very small effect

compared with assigning costs only to engines on U.S. vessels.

These costs are summarized in Table 6.2-2. Estimated costs are about $64,000 per engine. If

the standards apply to engines on both U.S. and foreign vessels, the estimated cost per engine

drops nearly to $6,000.
Chapter 6: Estimated Costs for Advanced Technologies

6-5

Table 6.2-2

Projected Costs per Engine for Engine Modifications

Amortization parameter Medium-speed

Engine

Low-speed

Engine

Total fixed

costs

R&D costs $874,000 $874,000

Retooling costs $40,000 $40,000

U.S. vessels

only

Engines per year 4 4

Fixed cost per engine $64,019 $64,019

Including

foreign vessels

Engines per year 40 40

Fixed cost per engine $6,402 $6,402

6.2.3 Direct Water Injection

Table 6.2-3 presents estimated costs for injecting water directly into the engine’s cylinders. 

Variable costs consider the various components and labor required to assemble the system,

including the cost of separate injectors for fuel and water. The estimated variable costs include a

markup, which reflects the technology development and overhead involved for the company

manufacturing the components and assemblies that the engine manufacturer will buy and

integrate into the overall engine design. The analysis does not incorporate a cost related to lost

cargo space as a result of water storage needs. The engine manufacturer’s fixed costs associated

with system integration allow for engineering time to optimize the control technology for

effective emission control while maintaining acceptable performance. This includes substantial

time for manufacturers to optimize in-cylinder controls in their efforts to produce an overall

system solution to incorporating water-injection technology. Total costs range from about

$120,000 to $320,000 depending on engine size. If emission standards apply also to engines on

foreign vessels, the estimated cost range is $50,000 to $250,000.

In addition, any ship using direct water injection would incur operating costs to keep the

system functioning. These operating costs are best quantified on an hourly basis. Total costs

depend on how long the systems run. This cost analysis is based on the expectation that ship

operators will activate the water-injection systems during the time that the ships are within 175

nautical miles of the U.S. coast. We estimate this annual operating rate to be 975 hours for U.S.

vessels and 149 hours for foreign vessels. Considering the population of these types of vessels

leads to a composite figure of 170 hours per year for all vessels. 

We consider two types of operating costs—water and fuel. At a cost of $0.10 per gallon for

distilled water, total estimated costs per year for U.S. vessels range from $4,000 to $23,000. 

Since foreign vessels spend less of their total operating time near the U.S., their estimated annual

water costs range from $600 to $3,600. Calculated as a net present value, with 7 percent

discounting to the point of sale, estimated composite costs are $120,000 for U.S. vessels and
Final Regulatory Support Document

6-6

$21,000 if we apply the standards to Category 3 engines on all vessels (see Table 6.2-4). Note

that these estimated water costs might be significantly reduced if a ship were designed to provide

its own supply of fresh water by adding a desalination plant (or increasing the capacity of an

existing desalination unit). 

We also estimate a 2-percent increase in fuel consumption for engines using direct water

injection for operation within 175 miles of the U.S. coast. This involves annual costs of $900 to

$5,500 per year for engines on U.S. vessels.3 Applying standards to Category 3 engines on all

vessels would result in estimated average per-engine costs of $200 to $1,000. 

As a sensitivity analysis, we consider the effect of operating a water-injection unit at all times

that the propulsion engine is running. To quantify this, we calculate revised operating costs for

increased fuel consumption and the greater amount of water used to control NOx emissions. The

composite calculation of operating costs yields an estimated net present value of $630,000, based

on an operating rate of 4,000 hours per year (see Table 6.3-2 to compare with other scenarios). 

This estimated cost applies equally to all vessels, regardless of their flag state. We would expect

no additional fixed or variable costs associated with producing a system designed to operate

continuously. On the other hand, a ship owner may substantially reduce operating costs by

investing in onboard water-production capability, as described above.
Chapter 6: Estimated Costs for Advanced Technologies

Table 6.2-3

Projected Costs per Engine for Direct Water Injection

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

Hardware cost to manufacturer

 water tank $2,600 $3,900 $5,200 $5,200 $10,400 $15,600

 low-pressure module $2,400 $3,600 $4,800 $4,800 $9,600 $14,400

 high-pressure module $4,800 $7,200 $9,600 $9,600 $19,200 $28,800

 flow fuses $3,000 $4,500 $6,000 $6,000 $12,000 $18,000

 water injectors $15,000 $22,500 $30,000 $30,000 $60,000 $90,000

 piping $1,400 $2,100 $2,800 $2,800 $5,600 $8,400

 control unit/wiring $1,000 $1,000 $1,000 $1,000 $1,000 $1,000

Total component cost $30,200 $44,800 $59,400 $59,400 $117,800 $176,200

Assembly @ $28/hr $1,882 $2,822 $3,763 $3,763 $7,526 $11,290

Total variable cost $32,082 $47,622 $63,163 $63,163 $125,326 $187,490

Markup @29% $9,304 $13,810 $18,317 $18,317 $36,345 $54,372

Total Hardware RPE $41,386 $61,432 $81,480 $81,480 $161,671 $241,862

Fixed costs

R&D — $874,000 — — $874,000 —

retooling — $250,000 — — $250,000 —

marine society approval — $5,000 — — $5,000 —

engines per year — 4 — — 4 —

years to recover — 5 — — 5 —

Fixed Cost per Engine $77,720 $77,720 $77,720 $77,720 $77,720 $77,720

Total Costs per Engine $119,106 $139,152 $159,200 $159,200 $239,391 $319,582

Including foreign vessels

Total Hardware RPE $41,386 $61,432 $81,480 $81,480 $161,671 $241,862

Fixed Cost per Engine $7,772 $7,772 $7,772 $7,772 $7,772 $7,772

Total Costs per Engine $49,158 $69,204 $89,252 $89,252 $169,443 $249,634
Final Regulatory Support Document

6-8

Table 6.2-4

Water costs for Direct Water Injection

Parameter

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

BSFC (g/kW-hr) 190 190 190 190 190 190

load factor 50% 50% 50% 50% 50% 50%

water/fuel ratio 40% 40% 40% 40% 40% 40%

water use (kg/hr) 152 228 304 304 608 912

water cost per kg $0.0264 $0.0264 $0.0264 $0.0264 $0.0264 $0.0264

water cost per hour $4 $6 $8 $8 $16 $24

total cost per year 

(U.S. vessels only)—

@ 975 hours/yr.

$3,900 $5,850 $7,800 $7,800 $15,600 $23,400

Present value 

(U.S. vessels only)

$43,962 $65,942 $87,923 $87,923 $175,846 $263,769

total cost per year 

(foreign vessels only)—

@ 149 hours/yr.

$596 $894 $1,192 $1,192 $2,384 $3,576

Present value 

(foreign vessels only)

$6,718 $10,077 $13,436 $13,436 $26,873 $40,309

total cost per year 

(composite)—

@ 170 hours/yr.

$680 $1,020 $1,360 $1,360 $2,720 $4,080

Present value 

(composite)

$7,665 $11,498 $15,330 $15,330 $30,660 $45,991

6.2.4 Selective Catalytic Reduction

Selective Catalytic Reduction (SCR) can be designed to operate at different levels of NOxreduction efficiency. Increasing NOx reductions correspond with higher costs. For this analysis,

system parameters are based on settings to allow an 80-percent reduction in NOx emissions. 

Later in this section, we consider the effect on costs of installing and operating a system set for

less effective NOx reduction. 

Variable costs include the various components and labor required to assemble the system and

integrate it into the vessel. The estimated variable costs include a markup, which reflects the

technology development and overhead involved for the company manufacturing the components

and assemblies that the engine manufacturer will buy and integrate into the overall engine design. 
Chapter 6: Estimated Costs for Advanced Technologies

6-9

The engine manufacturer’s fixed costs associated with system integration allow for engineering

time to optimize the control technology for effective emission control while maintaining

acceptable performance. This includes substantial time for manufacturers to optimize in-cylinder

controls in their efforts to produce an overall system solution to incorporating SCR technology.

Total costs range from about $260,000 to $1.23 million, depending on engine size. The expected

costs for very high-volume reactors for the largest engines involve oversize components and

additional engineering that substantially increase total estimated costs for those units. If

emission standards apply also to engines on foreign vessels, the estimated cost range is $220,000

to $1.18 million. Table 6.2-5 summarizes the estimated costs for such an SCR system. 

As described in Section 6.2.3, SCR units can be managed so that they operate only within

175 nautical miles of the U.S. coast, which leads us to calculate operating costs on an hourly

basis. For SCR, we consider three kinds of operating costs. First, a ship using SCR must

provide urea to the engine. At a cost of $1.30 per gallon for aqueous urea, total estimated costs

per year for U.S. vessels range from $9,000 to $53,000. Since foreign vessels spend less of their

total operating time near the U.S., their estimated annual urea costs range from $1,300 to $8,000. 

Calculated as a net present value, with 7 percent discounting to the point of sale, estimated

composite costs are $270,000 per engine for U.S. vessels and $48,000 per engine if we include

foreign vessels (see Table 6.2-5).

Second, SCR operation is more durable when engines operate on fuels with low

concentrations of sulfur. This may involve operation with a low-sulfur residual fuel, distillate

fuel, or a blend of these two fuel types. Further investigation would help us establish the specific

fuel requirements for maintaining SCR systems in the field. This analysis presents the estimated

costs associated with operation on distillate fuel within 175 nautical miles of the U.S. coast. We

believe that most vessels already have dedicated tanks available for storing distillate fuel. If a

vessel would need a new tank or an additional tank devoted to carrying distillate fuel, that would

involve an additional cost beyond what we consider in this analysis. Calculating the cost of

using a marine distillate fuel depends on an estimated load factor of 50 percent. Current prices

for the different fuel types shows an increase of about $75 per ton of fuel for switching to marine

distillate. This results in annual costs ranging from $28,000 to $170,000 per engine for U.S.

vessels. Including foreign vessels would drop these costs to a range of $5,000 to $29,000 per

engine. Fuel costs are discussed in Section 6.2.5.

Third, the analysis considers costs related to system maintenance. The SCR reactor may need

routine cleaning for optimum operation. This is performed through the use of either ultrasound

or compressed air. Ultrasound is performed by the use of an acoustic horn installed in the

reactor. The horn automatically sounds periodically while the engine is operating. The air

pulsation from the horn prevents soot from building up in the catalyst. The horn may be driven

by air from the normal air system installed on the vessel. This method requires no engine

shutdown. Using compressed air to clean the reactor would require a period of engine shut

down. In this method, a soot-blowing probe is inserted into the catalyst unit to remove soot. As

manufacturers gain experience with these systems, it will become clearer which of these cleaning

operations is preferred. For this analysis, we anticipate ten cleaning steps per year, taking 4
Final Regulatory Support Document

6-10

person-hours for medium-speed engines and 6 person-hours for low-speed engines. This results

in net-present value maintenance costs ranging from $18,000 to $26,000, as shown in Table

6.2-7. SCR reactors generally would need to be rebuilt or replaced after about 20,000 hours of

operation; however, we do not expect SCR units to operate so long over the life of a Category 3

marine diesel engine.

We consider two sensitivity analyses regarding SCR. First, similar to that described for water

injection, we calculate costs based on continuous operation of the SCR unit when the propulsion

engine is running. Increasing the annual operating rate to 4,000 hours and increasing to 25

cleaning steps in a year raises the composite operating costs to a net present value of $4.7 million

(see Table 6.3-2 to compare with other scenarios). This estimated cost applies equally to all

vessels, regardless of their flag state. We would expect no additional fixed or variable costs

associated with producing a system designed to operate continuously. 

For the second sensitivity scenario, we consider the cost effect of installing an SCR unit

designed to reduce emissions by only 50 percent. The less aggressive NOx reductions translate

into lower capital and operating costs based on published estimates for commercially available

systems.4

 This leads us to estimate a 10-percent lower level of fixed costs and a 30-percent lower

level for variable (or component) costs. This lower costs result mainly from designing and

producing a smaller, simpler reactor. The estimated composite cost per engine for an SCR unit

achieving a 50-percent NOx reduction is $415,000 for engines on U.S. vessels and $375,000 if

we include all vessels. Operating costs for urea would decrease approximately in proportion to

the NOx reduction. It is unclear whether a 50-percent SCR system would be more tolerant of

fuel sulfur or whether it would need the same fuel quality as an 80-percent system. If we make

fuel costs also proportional to percent reductions over 975 hours of operation (for U.S. vessels

only), we calculate a composite operating cost of $735,000 (net present value).
Chapter 6: Estimated Costs for Advanced Technologies

Table 6.2-5

Projected Costs per Engine for SCR

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

Hardware cost to manufacturer

 aqueous urea tank $2,600 $3,900 $5,200 $5,200 $10,400 $15,600

 reactor $120,000 $180,000 $240,000 $240,000 $480,000 $720,000

 dosage pump $4,400 $6,600 $8,800 $8,800 $17,600 $26,400

 urea injectors $7,500 $10,000 $15,000 $20,000 $40,000 $60,000

 piping $3,000 $4,500 $6,000 $6,000 $12,000 $18,000

 exhaust bypass valve $10,000 $15,000 $20,000 $16,000 $32,000 $48,000

 control unit/wiring $1,000 $1,000 $1,000 $1,000 $1,000 $1,000

Total component cost $148,500 $221,000 $296,000 $297,000 $593,000 $889,000

Assembly @ $28/hr $1,882 $2,822 $3,763 $3,763 $7,526 $11,290

Total variable cost $150,382 $223,822 $299,763 $300,763 $600,526 $900,290

Markup @29% $43,611 $64,908 $86,931 $87,221 $174,153 $261,084

Total Hardware RPE $193,993 $288,730 $386,694 $387,984 $774,679 $1,161,374

Fixed costs

R&D — $437,000 — — $437,000 —

retooling — $250,000 — — $250,000 —

marine society approval — $5,000 — — $5,000 —

engines per year — 4 — — 4 —

years to recover — 5 — — 5 —

Fixed Cost per Engine $47,168 $47,168 $47,168 $47,168 $47,168 $47,168

Total Costs per Engine $241,161 $335,898 $433,862 $435,152 $821,847 $1,208,542

Including foreign vessels

Total Hardware RPE $193,993 $288,730 $386,694 $387,984 $774,679 $1,161,374

Fixed Cost per Engine $4,717 $4,717 $4,717 $4,717 $4,717 $4,717

Total Costs per Engine $198,710 $293,447 $391,411 $392,701 $779,396 $1,166,091
Final Regulatory Support Document

6-12

Table 6.2-6

Urea costs for SCR

Parameter

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

BSFC (g/kW-hr) 190 190 190 190 190 190

load factor 50% 50% 50% 50% 50% 50%

aqueous urea rate 7.5% 7.5% 7.5% 7.5% 7.5% 7.5%

aqueous urea use (kg/hr) 29 43 57 57 114 171

aqueous urea cost per kg $0.3173 $0.3173 $0.3173 $0.3173 $0.3173 $0.3173

total cost per year 

(U.S. vessels only)—

@ 975 hours/yr.

$8,775 $13,650 $17,550 $17,550 $35,100 $52,650

Present value 

(U.S. vessels only)

$98,913 $153,865 $197,827 $197,827 $395,654 $593,481

total cost per year 

(foreign vessels only)—

@ 149 hours/yr.

$1,341 $2,086 $2,682 $2,682 $5,364 $8,046

Present value 

(foreign vessels only)

$15,116 $23,514 $30,232 $30,232 $60,464 $90,696

total cost per year 

(composite)—

@ 170 hours/yr.

$1,530 $2,380 $3,060 $3,060 $6,120 $9,180

Present value 

(composite)

$17,246 $26,828 $34,493 $34,493 $68,986 $103,479

Table 6.2-7

Maintenance costs for SCR

Parameter

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

Cleaning—per event $157 $157 $157 $235 $235 $235

Cleaning—NPV $1,570 $1,570 $1,570 $2,350 $2,350 $2,350

6.2.5 Fuel Costs

Table 6.2-8 presents the fuel costs we use in our analyses of various emission-control

approaches. These analyses include the costs of reducing fuel sulfur to enable SCR technology
Chapter 6: Estimated Costs for Advanced Technologies

6-13

and baseline fuel costs for a fuel consumption sensitivity analysis. Prices for residual fuel and

marine diesel oil come from Marine Bunker News.5 Note that these costs represent about a 50%

increase compared with the costs from January 2002 that were used in the analysis supporting the

proposal.6

 Given the volatility of fuel prices, it is clear that fuel-related cost estimates may

change significantly when we reconsider emission standards for Category 3 engines. Table 6.2-9

shows how these prices translate into increased operating costs when switching from the least

expensive residual fuel to marine distillate.

Table 6.2-8

Bunker Fuel Costs per Metric Ton (October 23, 2002)

Port Residual Fuel

380 centistokes

Residual Fuel

180 centistokes

Marine Distillate

Rotterdam $141-142 $145-146 $212-213

Fujairah $155-157 $160-161 $255-256

Singapore $153-154 $157-158 $232-236

Houston $144-145 $147-148 $218-220
Final Regulatory Support Document

6-14

Table 6.2-9

Costs of Switching from Residual Fuel to Marine Distillate Fuel to Enable SCR Technology

Parameter

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

BSFC (g/kW-hr) 190 190 190 190 190 190

load factor 50% 50% 50% 50% 50% 50%

increased fuel cost per

hour

$29 $43 $58 $58 $113 $171

total cost per year 

(U.S. vessels only)—

@ 975 hours/yr.

$28,267 $41,786 $56,534 $56,534 $110,609 $167,143

Present value 

(U.S. vessels only)

$318,629 $471,016 $637,257 $637,257 $1,246,808 $1,884,066

total cost per year 

(foreign vessels only)—

@ 149 hours/yr.

$4,320 $6,386 $8,639 $8,639 $16,903 $25,543

Present value 

(foreign vessels only)

$48,693 $71,981 $97,386 $97,386 $190,538 $287,924

total cost per year 

(composite)—

@ 170 hours/yr.

$4,929 $7,286 $9,857 $9,857 $19,286 $29,143

Present value 

(composite)

$55,556 $82,126 $111,112 $111,112 $217,392 $328,504
Chapter 6: Estimated Costs for Advanced Technologies

6-15

6.3 Total Engine Costs

6.3.1 Distribution of Category 3 Marine Engines

We can use the cost estimates presented above to develop an estimated composite cost for

applying advanced technologies to Category 3 marine diesel engines. This estimate is based on

the characteristics of the current fleet. Population data show that 60 percent of these are twostroke engines.7

 The average power rating for vessels using Category 3 marine engines is 11,000

kW. This average kW is based on data collected on seven U.S. ports that are available to oceangoing vessels.8

 Using these parameters, we estimated the distribution of engines shown in Table

6.3-1. While the actual distribution clearly covers a much wider range of engines and may

change before we propose emission standards requiring advanced technologies, this analysis

provides an initial estimate to assess the costs of incorporating advanced technologies.

Table 6.3-1

Estimated Distribution of Category 3 Engine Sizes

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 12 cyl.

20% 10% 10% 25% 20% 15%

6.3.2 Projected Composite Costs for Category 3 Engines 

We estimated composite costs for two of the technology approaches described in this

chapter—direct water injection and selective catalytic reduction. These costs are summarized in

Table 6.3-2. For direct water injection, the total estimated composite costs for U.S. vessels is

about $190,000. Annual operating costs are estimated at $14,000, with discounted lifetime

operating expenses estimated to be just over $150,000. Including foreign vessels would decrease

estimated composite engine costs to around $120,000 and lifetime operating expenses to

$26,000.

For SCR, the total estimated composite costs for U.S. vessels is about $580,000, based on

parameters that would allow for NOx emission reductions of about 80 percent. Annual operating

costs are estimated at $103,000, with discounted lifetime operating expenses estimated to be $1.2

million. Including foreign vessels would decrease estimated composite engine costs to $540,000

and lifetime operating expenses to $220,000.

The analysis is based on manufacturers recovering their fixed costs over a five-year period. 

Once these costs are fully amortized, they are removed from the analysis. Since fixed costs are

large and sales volumes are small, removing the fixed costs substantially reduces the estimated

long-term costs, as shown in Table 6.3-2. Long-term costs may also decrease as manufacturers
Final Regulatory Support Document

6-16

learn to produce emission-control technologies at a lower cost. We have not quantified the

learning effect in this analysis.
Table 6.3-2

Summary of Projected Costs per Engine for Advanced Technology

Technology

Package

Scope of

Standards Cost Parameter

Medium-speed Engines Slow-speed Engines

6 cyl. 9 cyl. 12 cyl. 4 cyl. 8 cyl. 

DirectWaterInjection

U.S. vesselsonly

Total cost per engine(yr. 1)

$119,105 $139,153 $159,201 $156,579 $239,391 $

Total cost per engine(yr. 6 and later)

$26,486 $39,317 $52,148 $50,470 $103,469 $

Operating costs (NPV) $55,912 $84,029 $111,824 $111,824 $223,971 $

U.S. andforeignvessels

Total cost per engine(yr. 1)

$49,157 $69,205 $89,253 $86,631 $169,443 $

Total cost per engine(yr. 6 and later)

$26,486 $39,317 $52,148 $50,470 $103,469 $

Operating costs (NPV) $9,749 $14,651 $19,497 $19,497 $39,051 

SCR

U.S. vesselsonly

Total cost per engine(yr. 1)

$241,160 $335,899 $433,863 $435,153 $821,847 $

Total cost per engine(yr. 6 and later)

$124,155 $184,788 $247,485 $248,310 $495,795 $

Operating costs (NPV) $435,240 $642,579 $852,782 $861,574 $1,668,952 $

U.S. andforeignvessels

Total cost per engine(yr. 1)

$198,709 $293,448 $391,412 $392,702 $779,396 $

Total cost per engine(yr. 6 and later)

$124,155 $184,788 $247,485 $248,310 $495,795 $

Operating costs (NPV) $90,500 $126,651 $163,302 $172,094 $312,868 $
Final Regulatory Support Document

6-18

1.“Emission Reduction Technology Costs for Category 3 Marine Diesel Engines,” Draft Report

from Louis Browning et al, Arthur D. Little–Acurex Environmental, March 2002.

2."Update of EPA's Motor Vehicle Emission Control Equipment Retail Price Equivalent (RPE)

Calculation Formula," Jack Faucett Associates, Report No. JACKFAU-85-322-3, September

1985 (Docket A-97-50; document IV-A-5).

3.The methodology for calculating costs (or savings) related to changes in fuel consumption are

documented in “Estimated Cost Impacts of Changing Fuel Consumption Rates for Category 3

Marine Diesel Engines,” EPA memorandum from Alan Stout to Docket A-2001-11, November

15, 2002 (Document IV-B-03).

4.“SCR Economics for Diesel Engines,” Ravi Krishnan, Diesel & Gas Turbine Worldwide, JulyAugust 2001 (Docket A-2001-11; document IV-A-04).

5. Bunker News, “Bunker Prices,” www.bunkernews.com, October 23, 2002.

6. Bunker News, “Bunker Prices,” www.bunkernews.com,

January 4, 2002 (Docket A-2001-11, document II-A-31).

7.Motor Ship, Annual Analysis, June 1999, pp. 49-50.

8. “Commercial Marine Activity for Deep Sea Ports in the United States: Final Report,”

ARCADIS Geraghty & Miller, Inc., prepared for U.S. EPA, June 30, 1999.

Chapter 6 References
Chapter 7: Inventory Baseline and Projections for Advanced Technology

7-1

CHAPTER 7: Inventory Baseline and Projections for

Advanced Technology

This chapter presents our analysis of emissions from Category 3 marine diesel engines. It

was developed under contract with E. H. Pechan & Associates, Inc.1

 The first section contains a

description of the methodology used to develop the baseline emission inventories for the base

year (1996). The second section contains a description of the methodology used to develop

inventory projections for future years. The next two sections contain the expected emission

reductions that would result from the long-term emission standards that reflect use of the

advanced technologies, both in the national inventories and on a per-vessel basis. We

investigated two advanced control scenarios: a 50 percent and an 80 percent reduction from the

standards we are finalizing.

This chapter is devoted entirely to emissions from Category 3 marine diesel engines. Our

analysis of emissions from Category 1 and 2 marine diesel engines was done in support of our

1999 rulemaking and can be found in the Final Regulatory Impact Analysis for that rule.2

7.1 Baseline Inventories

7.1.1 Geographic Boundaries

In developing emission inventories for Category 3 marine diesel engines, it is important to

consider the geographic area in which they operate. This is important because, unlike other

nonroad engines like trucks or locomotives, marine vessels may not operate all of the time within

the U.S. air shed. Therefore, we need to determine what portion of their operating time occurs

within the U.S., during which they contribute to U.S. air quality problems. For ships that operate

on the Great Lakes or inland waterways, our analysis counts all Category 3 marine diesel

emissions as occurring within the United States. For ocean-going vessels, we count only

emissions that occur while the vessel is operating within 175 nautical miles from the U.S. coasts. 

This 175-mile area is based on an estimate of the distance NOx molecules could travel in one day

(assuming a 10 mile per hour wind traveling toward a coast, NOx molecules emitted 12 miles

from the coast could reach the coast in just over one hour. NOx molecules emitted 175 nautical

miles, or 200 statute miles, from the coast could reach the coast in less than a day).

As noted in Chapter 2 and described in more detail below, the inventories were estimated in

two parts: in-port emissions are based on information for specific ports and are estimated for a

radius of 25 miles from port; non-port emissions are based on cargo movement data and cover

the area from 25 to 175 miles from the coasts. 

In our proposal we requested comment on the issue of pollutant transport and additional data

that would help us better understand the issue and thus develop a better estimate of how far off of

the coast we should be considering. We received some comments in favor of using the 175
Final Regulatory Support Document

7-2

nautical mile limit and no new data that would allow us to develop a better estimate. Thus, for

the purposes of this analysis the 175 nautical mile limit will be used. However, in support of

future rulemaking efforts we plan to continue researching the pollutant transport issue in an effort

to better understand how offshore emissions affect air quality on land.

7.1.2 Ports Inventories

For port areas we developed detailed emission estimates for nine specific port areas using

port activity data including port calls, vessel types and typical times in different operating modes. 

The nine port areas analyzed in detail were the Lower Mississippi (New Orleans and Baton

Rouge), New York, Delaware River (Philadelphia area), Puget Sound, Corpus Christi, Tampa,

Baltimore, Coos Bay, Cleveland and Burns Harbor. Vessel types considered included bulk

carrier, container ship, general cargo, passenger, refrigerated (reefer), roll-on roll-off (ro ro)

tanker, vehicle carrier, and other miscellaneous vessels.

Emission estimates for all other ports were developed by matching each of those ports to one

of the nine specific ports already analyzed based on characteristics of port activity, such as

predominant vessel types, harbor draft and region of the country. The detailed port emissions

were then scaled to the other ports based on relative port activity. Ports were looked at separately

for four main regions of the country; the Pacific Coast, the Gulf Coast, the Atlantic Coast, and

the Great Lakes.

For the port areas analysis three different types of vessel transit operation were considered. 

Cruising is when the vessel is approaching the port but not yet required to reduce its speed. The

reduced speed zone (RSZ) is the portion of the vessel’s approach to the port where it is required

to reduce its speed. Maneuvering includes vessel movement while in port (berthing or moving

from one berth to another). The relative amounts of these types of transit operation vary from

one port to another, depending on geography and traffic patterns. For example, port areas that

include some river transit have greater RSZ operation than other port areas. The load factor

(fraction of rated power) for cruise mode was assumed to be 80 percent. For RSZ operation the

load factor is generally between 15 and 35 percent, depending on vessel type and port geography. 

However, there are a few port areas where the RSZ load factor can go as high as 70 percent for

some vessel types. The maneuvering load factor is between ten and 12 percent.

This analysis was intended to characterize emissions specifically from Category 3 Marine

diesel engines, rather than vessels powered by Category 3 engines. Emissions from Category 3

vessels also include hotelling emissions, which are emissions generated in the process of

generating electric power for the vessel. In general, we assumed that most hotelling emissions

from Category 3 vessels are actually generated by Category 1 and 2 auxiliary engines, rather than

the main Category 3 propulsion engine. However, in the case of passenger vessels and reefer

ships, where the demand for electric power is great, we assumed that the hotel power is generated

by the category 3 propulsion engine. Thus, hotelling emissions from passenger and reefer ships

are included in the inventories, but not hotelling emissions from any other vessel types.
Chapter 7: Inventory Baseline and Projections for Advanced Technology

7-3

The ports emissions were calculated by associating and summing the product of the vessel

trips (port calls), vessel power, and average load factor by mode of operation and time in mode

for all modes of operation. The general equation used for calculating port emissions is shown

below.

Emissions = Trips × Power × LF in mode × Time in mode × EF

Where:Trips - number of trips or vessel calls by vessel and engine type

Power - rated power of propulsion engine by vessel and engine type

LF - load factor (fraction of rated power) by mode

Time - average time for each mode by vessel and engine type

EF - emission factor in mode and by engine type

Emission factors were developed separately for slow speed and medium speed Category 3

Marine diesel engines. The emission factors used are shown in Table 7.1-1.

Table 7.1-1

Emission Factors for Category 3 Marine Diesel Engine Transit Emissions (g/hp-hr)

Engine Type HC CO NOx PM SOx

Slow Speed 0.395 0.82 17.60 1.29 9.56

Medium Speed 0.395 0.52 12.38 1.31 9.69

Emission factors tend to be relatively steady at loads greater than 20 percent. Thus,

emission factors developed from emissions measured at full load were used as the cruise and

RSZ emission factors as well. However, at low loads the emission factors tend to increase as

compared with higher loads. The emission factors shown in Table 7.1-1 were used for cruise and

RSZ modes of operation. For maneuvering operation we adjusted the emission factors based on

relationships developed for us by Energy and Environmental Analysis, Inc.3

 The adjustments we

applied to the emission factors shown in Table 7.1-1 to develop maneuvering emission factors

are shown in Table 7.1-2.

Table 7.1-2

Ratio of Maneuvering Emission Factors at 10 percent Load to Full Load Emission Factors

Engine Type HC CO NOx PM SOx

Slow Speed 5.28 8.52 1.36 1.69 1.57

Medium Speed 5.50 7.41 1.36 1.68 1.55

The total national Category 3 Marine diesel inventories for within 25 nautical miles of all

U.S. ocean ports and 10 nautical miles of all U.S. Great Lakes ports are shown in Table 7.1-3.
Final Regulatory Support Document

7-4

Table 7.1-3

Total U.S. Category 3 Emission Inventories for Port Areas in 1996 (short tons)

HC CO NOx PM SOx

5,230 1,944 101,137 9,299 97,390

7.1.3 Non-Port Inventories

We developed non-port emission inventories using cargo movements and waterways data,

vessel speeds, average dead weight tonnage per ship, and assumed cargo capacity factors. We

assumed that all river traffic was handled by vessels with smaller than Category 3 engines, except

in river ports serving ocean-going traffic. Further, we assumed that any coastwise cargo

movement within 25 nautical miles of the coast, but outside of the port areas analyzed in section

7.1.1 was moved by tow and push boats powered by Category 2 engines. Thus, with the

exception of California, only non-port vessel traffic outside of 25 nautical miles from the coast

was considered to be Category 3 traffic for the purposes of this analysis. It is possible and, in

some cases likely that some Category 3 vessel traffic occurs within 25 nautical miles of the coast. 

However, the data did not include the type or size of vessel that the cargo was being transported

on, only the cargo tonnage. Thus, we were unable to discriminate between cargo carried on

Category 2 vessels and cargo carried on Category 3 vessels. Including cargo movement within

25 nautical miles of the coast but outside of ports areas would have resulted in the inclusion of

Category 2 vessel emissions in our baseline inventories for Category 3 vessels. Conversely,

excluding vessel traffic within 25 nautical miles of the coast likely excludes some Category 3

traffic. However, given that we could not separate Category 2 traffic from Category 3 traffic we

needed to err on one side or the other. We believe that excluding all non-port traffic within 25

miles of the coast gives us a more accurate estimate of non-port Category 3 emissions than

including it.

The U.S. Army Corp of Engineers provided activity estimates of total and domestic

tonnage by waterway links. A map of the waterway links is shown in Figure 7.1-1, at the end of

this chapter. 

 These estimates were converted to ton-miles of cargo by multiplying tonnage by link

distance to estimate overall link activity. In order to avoid double-counting the emissions

estimated in section 7.1.1 fractional links were estimated such that only traffic between 25 and

175 nautical miles from shore was considered. For Great Lakes links traffic outside of 10 miles

was considered. Emission factors in g/ton-nautical-mile were developed using cruise mode

emissions divided by the total freight tonnage from the detailed ports analysis. These emission

factors were then multiplied by the total links ton-miles to estimate total non-port emissions

inventories. The total non-port emission inventories for base year are shown in Table 7.1-4.
Chapter 7: Inventory Baseline and Projections for Advanced Technology

7-5

Table 7.1-4

Total U.S. Category 3 Emission Inventories for Non-Port Areas in 1996 (short tons)

HC CO NOx PM SOx

2,060 4,186 88,837 7,840 58,856

We are fairly confident in the accuracy of our ports emission inventory estimates given

that they were developed from the ground up using accurate port call information as well as

information on vessels types, etc. However, our non-port inventory estimate contains a greater

level of uncertainty than the in-port inventory estimates due to the exclusion of most Category 3

vessel traffic within 25 nautical miles of the coast. Thus, in support of future rulemaking efforts

we plan to continue researching the non-port emissions issue in an effort to further refine our

non-port emission inventories.

7.2 Future Year Baseline Inventory Projections

In order to project future year emission inventories for Category 3 Marine diesel engines

several factors were taken into account. These included the overall expected growth in cargo

movement, the type of vessel that would handle the increased freight movement (i.e., the future

makeup of the fleet), and the effect of the internationally negotiated NOx emission limits on fleet

emissions as older vessels are scrapped and replaced with new vessels.

The expected increase in freight movement was projected from estimates of freight

forecasts done by the U.S. Maritime Administration (MARAD). MARAD supplied estimated

freight forecasts for several types of vessels. Thus, rather than a single growth rate for all vessel

traffic, we used separate growth rates for tankers, container ships, cruise ships and other bulk and

general cargo ships. The MARAD estimates rely on historic freight growth from 1996 to 1999,

and varied between 2.2 and 6.6 percent per year, depending on vessel type. The growth rate from

1996 through 1999 was then projected beyond 1999 through 2004 by MARAD. For this analysis

the projections supplied by MARAD were used to project freight growth out to 2030. While

there is a great deal of uncertainty in projecting growth this far into the future, we did so to show

the possible impact of long-term standards on emission inventories. Given that Category 3

vessels typically last for several decades before being scrapped it is important to project

inventories out this far.

In order to project future vessel activity based on these forecasts of freight growth, the

overall dead weight tonnage (DWT) calling annually at ports and traversing the waterways links

was increased in proportion to the projected freight increases. The additional vessel calls needed

to accommodate the increased tonnage were added to the largest DWT category by vessel type. 

In other words, we assumed that the additional tonnage would be handled by the largest vessels

and powered by slow speed engines given that predominantly larger vessels are being constructed

to replace older vessels, and that ports are making an effort to accommodate larger vessels.
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In addition to the effects of increased freight tonnage and future changes in fleet makeup,

the effects of the internationally negotiated NOx limits were included in the future year

projections. Although these standards have not been ratified and do not yet have the force of

international law, they were written to be retroactive to the year 2000 when they do go into

effect. It is widely believed that most new vessels constructed beginning in 2000 have been built

in compliance with the internationally negotiated NOx limits. This is a trend that we expect to

continue. Thus, for this analysis we assumed that all Category 3 vessels constructed in 2000 and

later comply with the internationally negotiated NOx limits. The internationally negotiated NOx

limits are related to rated engine speed as shown in Table 1.1-1. This means that compliance

with the standards we are finalizing is incorporated into our baseline inventory, and we expect no

inventory benefits from our standards.

These NOx emission limits are for vessels tested on distillate fuel. However, Category 3

vessels use residual fuel in use. The use of residual fuel results in higher emissions than the use

of distillate fuel, and using the NOx limits without correcting for differences in fuels would result

in underestimating actual in-use emissions from vessels complying with the internationally

negotiated NOx limits. Thus, the standards were increased by ten percent to account for the

difference in fuels. In the absence of information regarding certification compliance margins (the

practice of producing engines which emit somewhat below the standards in order to provide a

compliance cushion) and in-use emission deterioration we used the actual internationally

negotiated NOx limits as the emission factors for future vessels in the growth projections.

The projected future emission inventories for the port areas are shown in Table 7.2-1. 

The non-ports inventory projections are shown in Table 7.2-2. Finally, the total national

inventory projections are shown in Table 7.2-3.

Table 7.2-1

Projected Emission Inventories from 

Category 3 Marine Diesel Engines in Port Areas (short tons) 

Year HC CO NOx PM SOx

1996 5,230 11,530 101,137 9,299 97,390

2010 8,501 18,836 146,160 14,199 104,540

2020 12,486 27,716 195,812 20,258 148,575

2030 19,146 42,535 287,511 30,447 222,640
Chapter 7: Inventory Baseline and Projections for Advanced Technology

7-7

Table 7.2-2

Projected Emission Inventories from 

Category 3 Marine Diesel Engines in Non-Port Areas (short tons) 

Year HC CO NOx PM SOx

1996 2,060 4,186 88,837 7,840 58,856

2010 3,295 6,681 127,955 11,797 88,261

2020 4,729 9,567 171,657 16,443 122,637

2030 7,005 14,088 243,294 23,784 177,106

Table 7.2-3

Projected Emission Inventories

 from Category 3 Marine Diesel Engines in All Areas (short tons) 

Year HC CO NOx PM SOx

1996 7,290 15,716 189,974 17,139 156,246

2010 11,796 25,517 274,115 25,996 192,801

2020 17,215 37,283 367,469 36,701 271,212

2030 26,151 56,623 530,805 54,231 399,746

7.3 Estimated Effects of Advanced Technology Standards on Inventories

This section presents estimated NOx inventory reductions that could occur from

standards that reflect the advanced emission-control technologies described in Chapter 5. We

examine two scenarios: standards set at 50 percent and 80 percent below the NOx standards we

are adopting in this rule (i.e., the internationally-negotiated NOx limits). Our estimated

inventory reductions are based on our current understanding of the U.S. fleet characteristics and

an effective date of 2007 for the new standards. We will revisit these estimates in our future rule. 

We are not estimating the benefits of potential PM, HC, or CO standards, but will revisit

standards for those pollutants and associated inventory reductions in our future rule.

To model the benefits of NOx standards that reflect application of the advanced

technologies, we applied an engine replacement schedule and the potential emission standards to

our inventory projections based on the standards we are finalizing in this rule (our baseline

inventory). For the purpose of estimating ship turnover rates, we used an average vessel age of

23 years. This is based on a study done by Corbett and Fishbeck in support of our 1999 rule

which estimated the average age of the U.S. fleet as 23 years.4

 A separate analysis of MARAD

data on ship calls to U.S. ports, which contained vessel age and flag information, showed that the

average age of U.S. vessels in 1999 was 24.2 years, with a median age of 22 years. The results of

this analysis are shown in Figure 7.3-1. It should be noted that the Corbett and Fishbeck study
Final Regulatory Support Document

7-8

suggests that the average age of the world fleet is lower than that of the U.S. fleet, which would

result in a faster turnover rate in the U.S. fleet than the in the world fleet. For the sake of this

study, however, we applied the U.S. turnover rate to all vessels, representing a worst-case

scenario. We intend to revisit this issue in our future rule.

Table 7.3-1 shows the Category 3 marine diesel engine NOx emission inventory estimates

for the two advanced technology standard scenarios, a 50 percent and 80 percent NOx reduction

from the levels we are finalizing in this rule, applied to U.S. vessels only and to foreign vessels. 

According to these estimates, standards that reflect a 50 percent reduction from the standards we

are finalizing in this rule would result in an additional 2 percent reduction by 2030 when applied

to Category 3 marine diesel engines on U.S. vessels only, and an additional 43 percent reduction

when applied to Category 3 marine diesel engines on all vessels that enter U.S. ports. Standards

that reflect an 80 percent reduction from the standards we are finalizing would result in an

additional 4 percent reduction by 2030 if applied to Category 3 marine diesel engines on U.S.

vessels only and nearly 70 percent reduction if applied to Category 3 marine diesel engines on all

ships that enter U.S. ports. The reductions associated with all vessels would be even larger if a

faster vessel turnover is assumed.

These estimates illustrate the importance of applying advanced technology standards to

engines on the broad group of vessels that use U.S. ports.

Table 7.3-1

Estimated 2030 Emission Inventories under Various 

Scenarios of Applying Long-Term Emission Standards 

2020 2030

Scenario NOx 

(1000 tons)

percent

reduction

NOx 

(1000 tons)

percent

reduction

Baseline (Annex VI) 367 -- 531 --

50% Reduction—U.S.

vessels only

360 2.1% 519 2.3%

50% Reduction—All

vessels

266 27.7% 301 43.3%

80% Reduction—U.S.

vessels only

355 3.4% 511 3.7%

80% Reduction—All

vessels

204 44.6% 160 69.8%
Chapter 7: Inventory Baseline and Projections for Advanced Technology

7-9

Figure 7.3-1

Table 7.3-2

Number of Category 3 Vessels in the U.S. Fleet by Age

Age (years) Number of vessels

0 - 9 32

10 - 19 65

20 - 29 130

30 - 39 40

40 - 49 11

50+ 15
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7.4 Per-Vessel Emission Reductions

This section describes our estimates of the emission reductions over the lifetime of an

average vessel for the two scenarios discussed above. These scenarios are a 50% reduction

beyond Tier 1 based on water injection and an 80% NOx reduction beyond Tier 2 based on

selective catalytic reduction. Under the 80% reduction scenario, we consider the use of distillate

fuel to be necessary to enable the use of SCR technology. Therefore, we calculate reductions in

PM (primarily direct sulfate PM) and SOx emissions due to the use of distillate fuel with a sulfur

content of 1.0% rather than residual fuel with a sulfur content of 2.7%.

To calculate the baseline per vessel annual emissions, we divide the total emissions

inventory presented in section 7.2 by our estimates of the number of vessels presented in Chapter

3. Emission reductions are determined by applying a percent reduction to the baseline emissions. 

Lifetime reductions are presented in Table 7.4-1 for applying future standards to U.S. vessels

only and for applying future standards to all vessels. The emission reductions are discounted at

7% and are based on the useful life discussed in section 7.3. Note that lifetime reductions are

lower for the entire fleet than for U.S. vessels. This is because we only count the emission

reductions within 175 miles of the U.S. coast. We estimate that the average U.S. vessel spends

about six times as much operation near our coast than the average foreign vessel.

Table 7.4-1: Discounted Per Vessel Lifetime Emission Reductions Beyond Tier 1 [short tons]

Pollutant U.S. Vessels Only All Vessels

50% Beyond Tier 1 NOx 639 112

80% Beyond Tier 1 NOx

PM

SOx

1,022

32

451

179

6

79

7.5 Cost Per Ton

Because we are not adopting long-term standards at this time, we have not calculated cost

per ton estimates for the future approaches. However this discussion gives guidelines on how

calculations could be made to provide information to facilitate comparison of options we will

consider in the future rulemaking. We will re-evaluate the costs and emission reductions of

specific standards and emission-control technologies when we propose the long-term standards.

The cost per ton is generally the per-engine costs divided by the per-engine emission

reductions. This analysis would examine total costs and total emission reductions over the

typical lifetime of an average marine diesel engine discounted to the beginning of the engine’s

life. This cost information is provided in Chapter 6 and the and emission information is provided

above. In calculating net present values that were used in our cost per ton estimates, we

generally use discount rates of 7 percent and 3 percent. OMB Circular A-94 directs us to

generate benefit and cost estimates reflecting a 7 percent rate. The 3 percent rate is consistent
Chapter 7: Inventory Baseline and Projections for Advanced Technology

7-11

with that recommended by the Science Advisory Board’s Environmental Economics Advisory

Committee for use in EPA social benefit-cost analyses, a recommendation incorporated in EPA’s

new “Guidelines for Preparing Economic Analyses” (November 2000).
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1. “Commercial Marine Emission Inventory Development,” E.H. Pechan and Associates, Inc.

and ENVIRON International Corporation, April, 2002. Air Docket A-2001-11, Document No.

II-A-67.

2. “Final Regulatory Impact Analysis: Control of Emissions from Marine Diesel Engines,” U.S.

EPA, November 1999. Air Docket A-2001-11, Document No. IV-A-05.

3. “Analysis of Commercial Marine Vessels Emissions and Fuel Consumption Data,” EPA420-

R-00-002, Prepared for EPA by Energy and Environmental Analysis, Inc., February, 2000. Air

Docket A-2001-11, Document No. II-A-64.

4. “Commercial Marine Emissions Inventory for EPA Category 2 and 3 Compression Ignition

Marine Engines in United Sates Continental and Inland Waterways,” James J. Corbett, Jr. and

Paul S. Fishbeck, Carnegie Mellon University, August 21, 1998. Air Docket A-2001-11,

Document No. II-A-65.

Chapter 7 References
Chapter 8: Test Procedure

8-1

CHAPTER 8: Test Procedure

In nonroad engine emission-control programs, the test procedures we use to measure

emissions are as important as the standards we put into place. These test procedure issues

include duty cycle for certification, in-use verification testing, emission sampling methods, and

test fuels. This chapter describes the test procedures specified in this rulemaking for the Tier 1

standards. It also includes information related to test procedure issues discussed in the Draft

Regulatory Support Document and likely to be considered again in the process of setting Tier 2

standards. 

8.1 Certification Test Procedures

We are specifying MARPOL NOx Technical Code (NTC) engine test procedures with

some modifications. These modifications are described in Section 8.1.4. Other sections describe

issues such as the duty cycle, test fuel and sampling procedures, which are not significantly

different from the NTC requirements. These procedures will be required for certification testing. 

We may allow other procedures to be used in the future if we adopt production testing and in-use

testing requirements.

8.1.1 Duty Cycle

We are specifying the same duty cycles as are used for testing NOx emissions under the

NTC requirements. These test cycles are designated by the International Organization for

Standardization (ISO) as the E3 and E2 cycles.1 The E3 duty cycle is designated for propulsion

marine diesel engines operating on a propeller curve. It represents heavy-duty diesel marine

engine operation on vessels greater than 24 meters in length. Many larger propulsion marine

engines do not operate on a propeller curve. These engines may run at a constant speed and use a

variable-pitch propeller to control vessel speed. The E2 constant-speed propulsion marine duty

cycle applies to these engines. Tables 8.1-1 presents duty cycles for main drive engines as

discussed above.
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8-2

Table 8.1-1

Test Cycle Types E2 and E3

Test Cycle Type E2a

Speed 100% 100% 100% 100%

Power 100% 75% 50% 25%

Weighting Factor 0.2 0.5 0.15 0.15

Test Cycle Type E3b

Speed 100% 91% 80% 63%

Power 100% 75% 50% 25%

Weighting Factor 0.2 0.5 0.15 0.15

a

E2: for constant-speed main propulsion application (including diesel-electric drive or variable-pitch propeller

installation)

b

E3: for propeller-law-operated main and propeller-law-operated auxiliary engine application

8.1.2 Test Fuel

Category 3 engines are typically designed to burn residual fuel, which is a heavy byproduct of the refining processes used to produce lighter petroleum products such as gasoline,

diesel fuel and kerosene. However they can also burn distillate fuel. In order to harmonize with

the NTC testing provisions in the near term, we are specifying distillate fuel for Tier 1 testing. 

However, this section provides additional information regarding residual fuels, and discusses

why we may need to specify one or more residual fuels when we consider more stringent

standards in the future. 

Residual fuel is a dense and viscous fuel that is a byproduct of distillate fuel productions. 

It typically has higher ash, sulfur and nitrogen content than marine distillate fuels. Some

Category 3 engines can burn straight residual fuel, but many burn a blend of residual and

distillate, which is called intermediate fuel (IF). The two most common IF blends burned in

Category 3 engines are IF 180, which contains about 88 percent residual fuel and IF 380 which

contains about 98 percent residual fuel.2

 Table 8.1-2 summarizes current ASTM standards for a

marine distillate oil, residual fuel, and these two common IF blends.
Chapter 8: Test Procedure

8-3

Table 8.1-2

Comparison of ASTM Fuel Specifications3

Units Distillate fuel IF 180 IF 380 Residual fuel

ISO-F symbol DMA RMF-25 RMH-35 RML-55

Density @ 15C, max kg/m3 890 991 991 no max

Viscosity @ 40C cSt 1.5-6.0 316 ~710 —

Viscosity @ 50C cSt — 180 380 —

Viscosity @ 100C cSt — 25 35 55

Carbon Residue, max wt% 0.20a 20b 22b no max

Ash, max wt% 0.01 0.15 0.2 0.2

Sulfur, max wt% 1.5 5 5 5

a

Ramsbottom test

b

Conradson test

The use of residual fuel has two important consequences. First, it is more difficult to

handle. Because of its high viscosity and high impurities, the fuel must be heated and filtered

before it can be passed to the engine. This requires additional equipment and space. Bunker

fuel is kept in a main fuel tank where it is kept heated, generally using steam coils, to just above

its pour point. Prior to use, this fuel is pumped into a settling tank, where the heavier portions

settle to the bottom. Fuel is pumped from the top of the settling tank through heaters, centrifugal

separators, and filters before entering the fuel metering/injection pump(s). The centrifugal

separators and filters remove water and remaining sludge from the fuel. The sludge is then

routed to a sludge tank. In addition, a separate fuel tank is usually necessary to store a lighter

fuel which is used to start a cold engine. 

Second, residual fuels can have detrimental effects on engine emissions. These fuels can

contain one percent or more nitrogen by weight, and fuel-bound nitrogen is completely converted

to NOx in diesel engines.4

 Assuming complete conversion to NO2, one gram of nitrogen in the

fuel would result in 3.28 grams of NOx, based on the ratio of molecular weight of NO2 (46.005)

to the atomic weight of nitrogen(14.007). Based on the currently available information, it is

appropriate to assume conversion to NO2, since our proposed test procedures convert NO

emissions to NO2 before measurement and calculates the total NOx emissions assuming the

molecular weight of NO2. It is possible that some of the fuel nitrogen would be converted to

other nitrogen compounds such as NH3 (ammonia) or N2O (nitrous oxide), or remain bound to

organic molecules in the HC or PM emissions. However, since about 99 percent of the fuel mass

consumed by a Category 3 engine is typically converted to CO or CO2, it is unlikely that a large

amount of the fuel nitrogen remains organically bound. Also, given the high air/fuel ratios, it

seems unlikely that a significant amount of NH3 or N2O would be produced. The primary

uncertainty is related to the formation of elemental nitrogen (N2). One commenter suggested that
Final Regulatory Support Document

8-4

some of the combustion occurs at equilibrium conditions, where a significant fraction of the fuelbound nitrogen would be converted to N2. 

Residual fuel quality can effect emission in ways other than the effect of fuel nitrogen. 

Bastenhof analyzed emission results for ISO E3 test results of a Category 3 engine that showed a

22 percent increase in ISO weighted NOx when residual fuel was substituted for distillate fuel.5

However, most of the difference could not be attributed to the effect of the fuel-bound nitrogen

(0.4 percent). A large fraction of the NOx increase was attributed to the fuel’s poor ignition

quality, which caused excessive ignition delay at part load. At 25 percent load on residual fuel,

the engine produced 50 percent more NOx than on distillate, while at full load it produced only

25 percent more than on distillate. 

We recognize that the effects of fuel-bound nitrogen are not yet fully understood, and we

are not aware of any accurate corrections for fuel effects other than the effect of fuel nitrogen. 

Thus we believe that it is appropriate to specify distillate fuel as an interim provision limited to

Tier 1 testing. However, we believe that for the longer term, it will probably be necessary to base

our standards on more representative test fuels. We expect to work with manufacturers to

develop more accurate corrections for nitrogen and other fuel effects.

8.1.3 Sampling Procedures and Calculations

The NTC test procedures use a conventional raw sampling system, in which a small

sample of the exhaust gases is drawn from the exhaust stack and pumped through chemical

analyzers. NOx concentrations in the sample are measured using a chemiluminescence analyzer. 

CO2 concentrations are measured using a Non-Dispersive Infrared analyzer. These analyzers are

the same as the analyzers specified by EPA for other nonroad standards. 

The NTC provisions specify that NOx emissions be corrected to be equivalent to

measurements made at a reference humidity of 10.71 g of water per kg of dry air (g/kg). They

also specify that NOx emissions be corrected for the effect of seawater temperature on charge air

cooling.

8.1.4 Modifications to the NOx Technical Code Test Procedures

We are adopting test procedures with several modifications and additions relative to the

NTC test procedures to better ensure that the emission measurements will accurately represent

in-use performance. We require that inlet air and exhaust restrictions be set at the average in-use

levels. Similarly, engine coolant and engine oil temperatures must be equivalent to the

temperatures that will occur in-use under ambient conditions identical to the test conditions. 

Measurements must be valid only for sampling periods in which the temperature of the charge air

entering the engine is within 3C of the temperature that would occur in-use under ambient

conditions (temperature, pressure, and humidity) identical to the test conditions. Manufacturers

may measure emissions within larger discrepancies, but may not use those measurements to
Chapter 8: Test Procedure

8-5

demonstrate compliance with these regulations. The NTC procedures allow manufacturers

significantly more discretion with respect to these parameters. 

The NTC allows g/kW-hr emission rates to be calculated using measured exhaust flow

rates. However, we do not believe that exhaust can be reliably measured for Category 3 engines. 

Measuring exhaust flow rates in general is difficult due to the high temperatures and the

variability of exhaust temperatures. We believe it would be even more difficult for very large

engines. Exhaust stacks for Category 3 engines can be over a meter in diameter, which allows

for significant spatial variation in the flow rate. Exhaust flow rates must therefore be calculated

using measured fuel flow rates.

The duty cycle used for NTC testing specifies the test points based on the manufacturer's

specified rated speed. We have concerns about the subjective nature of the NTC requirement and

believe that the test cycle needs to be defined more objectively. Test cycles must therefore be

denormalized based on the maximum test speed described in §94.107, which is derived from the

lug curve for the engine. This maximum test speed is not intended to fundamentally change the

test procedure, but merely makes the procedure less subjective. We are including an option for

manufacturers to use the maximum in-use engine speed for governed engines.

8.2 Shipboard NOx Emission Measurement System

We proposed that Category 3 diesel engines have a direct exhaust NOx monitoring

system. This system was to be used to verify that engines are adjusted properly in use. It could

also be used for production testing. We are not finalizing this requirement for Tier 1, but expect

to adopt such a requirement when we consider more stringent standards in the future. 

Category 3 engines typically have fuel injection timing and other adjustments that are

optimized to accommodate a range of fuel qualities and environmental conditions. Since these

engine adjustments also affect NOx emissions, it would be valuable to have a shipboard means of

monitoring NOx to ensure that the engine is adjusted to remain in compliance with the applicable

standards. Indirect methods for inferring NOx emissions based on engine operating

temperatures, pressures or flows will not ensure compliance with applicable standards due to the

complex relationship between these parameters and NOx emissions. Onboard measurements

would also be necessary for other treatment technologies that can be adjusted to operate at

different emission-control efficiencies, such as water injection. Another one of the reasons we

proposed to require these measurement systems was to enable operators to effectively turn

emission controls off under certain conditions by adjusting the engine.

We envision that the NOx monitoring system would perform the following functions. It

would detect exhaust NOx concentration in parts per million (ppm) and integrate this

measurement with other shipboard measurements so that the measured concentration may be

compared with emission limits (or targets) for an engine’s operating conditions. These targets

would be determined by the engine manufacturer, and would vary with operating conditions and

fuel quality. The system would display the NOx concentration and the respective specified
Final Regulatory Support Document

8-6

emission limit at the engine control room. This kind of system would give the marine engineer

immediate and specific feedback regarding any recent adjustments to the engine or any recent

changes in fuel quality or environmental conditions. Displaying actual values of emissions rather

than merely activating an alarm would serve to familiarize the marine engineer with the

magnitude of the change in NOx emissions versus various changes in engine operation, fuel

quality, or environmental conditions. As the marine engineer incorporates NOx monitoring with

the rest of the ship's engine monitoring, it is likely that NOx emissions may be incorporated to

troubleshoot or optimize the engine's operation. NOx is sensitive to combustion temperature

which is a function of engine load, fuel injection timing, fuel ignition delay, combustion air inlet

temperature, and a few other engine parameters to a lesser extent. Unusually high or low NOx

emissions might indicate to the marine engineer that these parameters should be carefully

inspected to ensure proper engine operation.

The system should also provide automated calibration and error handling, including

audible and visual alarms to ensure proper operation with a minimum of maintenance. In order

for a system such as this to be well-received and properly used aboard ship, the system must not

significantly increase the day-to-day work load of the marine engineer. It is expected that

periodic repair and maintenance would be required to keep the system in proper working order,

however, it should be designed to require tedious calibration or frequent maintenance, since that

would likely discourage operators from using it properly.

The system should also permanently record the NOx concentration and any other

measured or calculated parameters, including the respective limit for the engine operating

conditions, the calibration results, plus any system alarms or malfunctions. This record would be

used to determine whether or not the engine is being operated consistent with its intended

operation (i.e. operation during engine certification.) This record would also be useful in

determining how well the NOx monitoring system is maintained.

8.2.1 System Description and Component Specifications

The NOx monitoring system that we proposed consisted of several components, and the

system is illustrated in the figure below.
Chapter 8: Test Procedure

8-7

Engine

T/C T/C

Stack Probe

Sample Conditioning

System (as required)

NOx Analyzer

Analyzer Exhaust

Engine Room Control Room

Display

Data

Recorder

Cable

Controller

Engine

T/C T/C

Stack Probe

Sample Conditioning

System (as required)

NOx Analyzer

Analyzer Exhaust

Engine Room Control Room

Display

Data

Recorder

Cable

Controller

Figure 8.2-1

8.2.1.1 Location of Sample Extraction Point

A sensor or sampling probe would be located at a position in the exhaust stream where

the exhaust from all engine cylinders are well-mixed. It is important that the exhaust be

well-mixed because each fuel injection pump and after-cooler may be adjusted individually on a

typical Category 3 engine. This means that some cylinders of the engine might be producing

more NOx than others. A well-mixed sample would not only help ensure compliance to the

applicable standard, but it would also prevent false positive indications that the engine is emitting

excessive NOx emissions. A multi-point transverse sampling probe would need to be used only

if the exhaust system does not provide for a single point location where the exhaust is

well-mixed. Sound engineering judgment must be used to determine this position in the exhaust

system, however, it is recommended that the Reynolds number of the exhaust flow at the

sampling position remain greater than 4000 and that the sensor or sampling position be in the

free stream flow at least five exhaust trunk diameters downstream of any trunk junctions or 90

bends.

The sampling position should be selected to prevent periodic exhaust system cleaning

from adversely affecting the sensor or probe. Category 3 engines often have exhaust heat

recovery devices such as economizer boilers. These components require periodic steam cleaning
Final Regulatory Support Document

8-8

(soot-blowing). The action of the soot blowers might damage a NOx sensor or sample probe

placed in the exhaust stream, therefore the sample location should be upstream of these devices. 

This location must also be upstream of any other exhaust stream that might be introduced

into the exhaust system. Other engines or boilers might exhaust to the same system, and their

exhaust would most certainly cause the recording of erroneous data.

8.2.1.2 Sample conditioning system 

 Depending on which NOx detection method is used, a sample conditioning system may

be needed. The sample conditioning system could consist of filters, scrubbers, or chillers. 

However, no component of the sampling system should affect the NOx concentration of the

sample. For example, if a sample conditioning system utilized unheated lines or a chiller that

brings the sample below its dewpoint, an NO2 to NO converter would have to be used upstream

to prevent the precipitation of NO2 as nitric acid.

8.2.1.3 NOx Analyzer

To quantify total NO + NO2, a NOx analyzer would be used to quantify the exhaust NOx

concentration in parts per million by volume (ppm). The performance specifications of the NOx

analyzer would be as follows: the detection range of the analyzer would be at least 100-5000 ppm 

with a NIST traceable accuracy of ±2% at each calibration point (i.e. ±10 ppm at 500 ppm

concentration of an NIST traceable calibration gas), a precision of ±5% based on two standard

deviations (2) and a 90% response time of less than 5 seconds to an 80% of full-scale step

change in NOx. These specifications ensure that the analyzer would be able to detect a

significant change in NOx emissions without over-specifying an analyzer that might require more

frequent maintenance or a more complicated calibration procedure.

In addition the analyzer must have an automated calibration subsystem that would

perform quality control and quality assurance checks to ensure that NOx is measured at the stated

specification. This level of automation is required to prevent an undue increase in the marine

engineer's day-to-day workload. Automated calibration subsystems are commercially available

for gas detection systems and are already used aboard tankships that require gas detection

systems for safety purposes.

Any analyzer must be designed to perform under typical shipboard temperature, humidity,

shock, vibration, electromagnetic and radio frequency interference. It is also important that the

analyzer not have any cross-sensitivity to other exhaust constituents. Several different NOx

detectors have been used successfully to detect NOx of roadway diesel engine exhaust. 

However, Category 3 engines frequently use residual fuel that contains high concentrations of

components not found in distillate diesel fuel. These components include sulfur at 100 times

distillate diesel concentrations plus metallic ash from crude oil and catalytic refining processes. 

Such components might cause fouling or corrosion of wetted parts of the NOx monitoring
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system. Analyzer manufacturers would have to use care when selecting certain materials and

detectors for use in this application.

Analyzers based on chemiluminescent, non-dispersive ultra-violet, zirconia cell, or

Fourier transform infra-red measurement techniques could likely work for shipboard use. 

However, the instrument manufacturer would have to ensure that an analyzer meets the necessary

specifications. Except for the zirconia cells that can be inserted directly into the free stream

exhaust, all of these analyzers would require a sample of the exhaust to be extracted. This means

that these analyzers would have to include their own pumping subsystem. In addition the

analyzer exhaust would have to be routed back to the engine’s exhaust.

There is already an indication that the zirconia cell shows promise in the harsh residual

fuel exhaust. A report submitted to the International Maritime Organization indicated that a

zirconia cell sensor was used aboard three different Category 3 engine-equipped vessels using

seven different residual fuels, and after six months of use the zirconia sensor continued to

perform acceptably.7

 Some of the advantages of the zirconia sensor include its cost, currently in

the several hundred U.S. dollar range for the sensor, and under $4,000 for the entire analyzer. It

is anticipated that a complete NOx monitoring system might cost approximately $15,000 with

annual operating costs (including labor) of approximately $5,000. Cost of the complete system is

minimal because the zirconia cell does not require a sample conditioning system or pump. 

However, a pump and a sample conditioning system might be used to prolong a zirconia cell’s

life.

8.2.1.4 Programmable Controller

A programmable electronic controller should be able to execute all of the system

functions such as sampling, calibrating, purging, and error handling. The controller would

integrate other shipboard measurements and make all necessary calculations. The controller

would also allow for manual operation of the system. Such a controller may vary in

sophistication depending upon the needs of the ship and the availability of other centralized

automation systems, which might be able to perform the NOx monitoring functions.

8.2.1.5 Engine Control Room Display

In a well-designed system, an engine control room display would probably provide the

marine engineer with a continuous display of measured NOx concentration and the respective

NOx limit for the engine operating condition, plus any other relevant measurements or calculated

values. The display would also indicate any alarms or faults so that repair or maintenance could

be promptly performed. The display would also provide for remote control of the system.

8.2.1.6 Data Recorder

To make the system reliable as an enforcement tool, a data recorder would be needed to

permanently document all of the NOx monitoring system’s measured and calculated parameters,
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calibration results, and system errors. All data would be recorded along with date and time

stamps, and this record would be used to determine compliance with applicable NOx emission

requirements. It would also be used by the marine engineer to determine day-to-day changes in

NOx emissions or even NOx trends over the life of the engine. This data would be permanently

archived consistent with shipboard practices for retaining records such as the course recorder

logs or other similar permanent records.

8.2.2 Emission Targets

We expect that the typical onboard measurement system would report the concentration

of NOx in the exhaust (ppm) along with other test conditions (e.g., engine speed, shaft torque,

fuel properties, ambient temperature and humidity, etc.). We do not expect that these results

would be directly comparable to the weighted g/kW-hr emission standards. Thus, we will likely

need to require the engine manufacturer to develop NOx-ppm emission targets for each set of

conditions if we adopt in a future rule the kind of adjustability allowances that we proposed. 

These targets would be indicative of equivalent emission-control performance. 

Equivalent emission-control performance could be defined relative to optimal engine

performance that could be achieved in the absence of emission standards (i.e., the calibration that

result in the lowest fuel consumption and/or maximum firing pressure). This approach would

work for NOx controls in which there would be a tradeoff between NOx emissions and fuel

consumption rates. The most obvious example of this would be fuel injection timing. In this

case, equivalent performance could mean the same percent reduction in NOx emissions from the

optimal calibration as is achieved under the test conditions. Alternatively, the manufacturer

could achieve equivalent performance by specifying that the timing be retarded the same number

of degrees from the optimal calibration as was done under the test conditions. In this alternative

approach, the calibration would be conceptually equivalent to a mechanically-controlled engine.
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1. International Organization for Standardization, 8178-4, “Reciprocating internal combustion

engines—Exhaust emission measurement—Part 4: Test cycles for different engine applications.” 

2. The Bunker News Daily, “Flashpoint,” MRC Publications, July 17, 1997, Vol. 1 No. 137,

www.bunkernews.com.

3. International Organization for Standardization, 8217, 1987. 

4. Heywood, J., Internal Combustion Engines, McGraw-Hill, New York, p. 577, 1988.

5. Bastenhof, D., “Exhaust Gas Emission Measurements; A Contribution to a Realistic

Approach,” CIMAC, May 1995.

Chapter 8 References