TECHNICAL SUPPORT DOCUMENT:

INITIAL STATEMENT OF REASONS FOR

PROPOSED Rulemaking

PROPOSED REGULATION FOR COMMERCIAL HARBOR CRAFT

Stationary Source Division

Emissions Assessment Branch

September 2007
State of California

AIR RESOURCES BOARD

Technical Support Document: 

Proposed Regulations for Commercial Harbor Craft

Public Hearing to Consider

ADOPTION OF PROPOSED REGULATIONS

TO REDUCE EMISSIONS FROM DIESEL ENGINES ON

COMMERCIAL HARBOR CRAFT OPERATED WITHIN CALIFORNIA WATERS

AND 24 NAUTICAL MILES OF THE CALIFORNIA BASELINE

To be considered by the Air Resources Board at a two-day meeting of the Board that 

will commence on October 25 and may continue to October, 26, 2007, at:

California Environmental Protection Agency

Headquarters Building

Byron Sher Auditorium

1001 I Street

Sacramento, California 95814

Stationary Source Division

Robert Fletcher, Chief

Robert Barham, Ph.D., Assistant Chief

Emissions Assessment Branch

Daniel E. Donohoue, Chief

Health and Exposure Assessment Branch (RD)

Linda Smith, Ph.D., Chief

Control Strategies Section

Cherie Rainforth, Manager

Technical Assessment Section

Peggy Taricco, Manager

Regulatory Support Section (PTSD)

Todd Sax, Ph.D., Manager

This report has been prepared by the staff of the Air Resources Board. Publication 

does not signify that the contents reflect the views and policies of the Air Resources 

Board, nor does mention of trade names or commercial products constitute 

endorsement or recommendation for use. 
State of California

AIR RESOURCES BOARD

PROPOSED REGULATIONS FOR

COMMERCIAL HARBOR CRAFT 

Principle Author

Todd Sterling

Contributing Authors

Kirk Rosenkranz

John Lee

Kathleen Truesdell

Pingkuan Di, Ph.D.

Lisa Williams

Bonnie Soriano 

Doug Grandt

Chengfeng Wang, Ph.D. 

Reza Mahdavi, Ph.D.

Hien Tran

Joe Calavita

Legal Counsel

Floyd Vergara, P.E., Office of Legal Affairs

Supporting Divisions

Mobile Source Control Division

Planning and Technical Support Division 

Research Division 

Acknowledgements

This report was prepared with the assistance and support from the other divisions and 

offices of the Air Resources Board. In addition, we would like to acknowledge the 

assistance and cooperation that we have received from many individuals and 

organizations. 
i

TABLE OF CONTENTS

Contents Page

I. Introduction......................................................................................................................I-1

A. Need for Proposed Regulation.........................................................................I-1

B. Summary of Proposed Regulation...................................................................I-3

II. Regulatory Status and Public Outreach.....................................................................II-1

A. Regulatory Authority..........................................................................................II-1

B. Summary of Existing Regulations and Programs.........................................II-3

C. Environmental Justice and Public Outreach.................................................II-6

III. Harbor Craft Inventory and Emissions ......................................................................III-1

A. Harbor Craft Inventory, Descriptions, and Uses..........................................III-1

B. Marine Engines in Harbor Craft Vessels .......................................................III-6

C. Marine Engine Emission Standards ..............................................................III-7

D. Estimated Emissions from Harbor Craft .......................................................III-9

IV. Health Impacts of Current Harbor Craft Emissions ................................................ IV-1

A. Potential Health Impacts of Harbor Craft Emissions.................................. IV-1

B. Estimating Potential Cancer Impacts near California Ports...................... IV-2

C. Estimating Potential Non-Cancer Impact of Emissions from 

Harbor Craft Engines ...................................................................................... IV-5

D. Assumptions and Limitations of Health Impacts Assessment.................. IV-8

V. Proposed Control Measure .........................................................................................V-1

A. Summary of the Proposed Regulation..........................................................V-1

B. Discussion of the Proposed Regulation........................................................V-2

VI. Feasibility of the Proposed Regulation ....................................................................VI-1

A. Repowering Vessels .......................................................................................VI-1

B. Statewide Capacity for Engine Replacements............................................VI-2

C. Grant Funding Availability ..............................................................................VI-5

D. Alternative Emission Control Strategies ......................................................VI-6

E. In-Use Experience with Diesel Emission Control Strategies ....................VI-9

F. Feasibility of Achieving Additional Emission Reductions from

New-Build Ferry Propulsion Engines..........................................................VI-11
ii

TABLE OF CONTENTS (cont.)

Contents Page

VII. Environmental Impacts ..............................................................................................VII-1

A. Legal Requirements .......................................................................................VII-1

B. Effects on Air Quality......................................................................................VII-2

C. Health Benefits Analysis................................................................................VII-5

D. Reasonable Foreseeable Environmental Impacts as a Result of

 Potential Compliance Methods ..................................................................VII-11

E. Reasonably Foreseeable Mitigation Measures .......................................VII-15

F. Reasonably Foreseeable Alternative Means of Compliance with the 

Proposed Regulation...................................................................................VII-15

G. Impact on Global Warming..........................................................................VII-15

VIII. Economic Impacts......................................................................................................VIII-1

A. Summary of the Economic Impacts............................................................VIII-1

B. Legal Requirements ......................................................................................VIII-3

C. Methodology for Estimating Costs Associated with Proposed

Regulation.......................................................................................................VIII-3

D. Total Regulatory and New Equipment Costs ..........................................VIII-12

E. Estimated Costs to Businesses.................................................................VIII-17

F. Potential Costs to Local, State, and Federal Agencies .........................VIII-20

G. Cost-Effectiveness.......................................................................................VIII-21

H. Availability of Incentive Funding ................................................................VIII-24

I. Analysis of Alternatives...............................................................................VIII-27
iii

TABLE OF CONTENTS (cont.)

Appendices Page

Appendix A: Proposed Regulations for Commercial Harbor Craft ..................................A-1

Appendix B: Emissions Estimation Methodology for Commercial Harbor Craft

Operating in California.....................................................................................B-1

Appendix C: Diesel Particulate Matter Exposure Assessment Study for the

Ports of Los Angeles and Long Beach Final Report...................................C-1

Appendix D: Statewide Commercial Harbor Craft Survey Final Report.........................D-1

Appendix E: Technology Evaluation ...................................................................................E-1

Appendix F: Non-Cancer Health Risk ................................................................................. F-1
iv

TABLE OF CONTENTS (cont.)

List of Tables Page

Table II-1: U.S. EPA Marine Engine Categories Used in Harbor Craft ....................II-2

Table II-2: U.S. EPA Tier 1 Standards for Marine Diesel Engines

Used in Harbor Craft......................................................................................II-3

Table II-3: U.S. EPA Tier 2 Standards for Marine Diesel Engines

Used in Harbor Craft......................................................................................II-4

Table II-4: Proposed U.S. EPA Tier 3 Standards for Marine Diesel Engines

Used in Harbor Craft......................................................................................II-4

Table II-5: Proposed U.S. EPA Tier 4 Standards for Marine Diesel Engines

Used in Harbor Craft......................................................................................II-5

Table II-6: Workshop/Outreach Meeting Locations and Times .................................II-8

Table III-1: 2004 Statewide Population of Harbor Craft by Vessel Type..................III-2

Table III-2: Number of Engines and Average Engine Horsepower for Typical

Harbor Craft ...................................................................................................III-7

Table III-3: U.S. EPA Marine Engine Standards Effective Dates and 

Emission Limits for Category 1 and Category 2 Engines

Used in Harbor Craft.....................................................................................III-8

Table III-4: Comparison of Tier 2 Standards, Offroad versus Marine Engines .......III-9

Table III-5: Estimated “Tier 0” or Unregulated Marine Engine Emissions ............. III-10

Table III-6: 2004 Populations of Vessels and Numbers of Engines

by Vessel Type........................................................................................... III-11

Table III-7: Estimated 2004 Statewide Harbor Craft Emissions ............................. III-12

Table III-8: Estimated 2004 Harbor Craft Emissions by District ............................. III-15

Table III-9: Harbor Craft Emissions Projected Year 2015 and 2020

Emission Estimates ................................................................................... III-16

Table IV-1: Summary of Area Impacted and Population Affected by Risk Levels

from Harbor Craft (emission inventory based on 2002 port calls)........ IV-4

Table V-1: U.S. EPA Marine Engine Standards and Implementation Years ........V-10

Table V-2: Compliance Dates for Vessels with Homeports Outside

SCAQMD......................................................................................................V-12

Table V-3: Compliance Dates for Vessels with Homeports in SCAQMD ..............V-12

Table VI-1: Statewide Engine Replacement Capacity................................................VI-4

Table VI-2: Alternative Marine Application Emission Control Strategies .................VI-7

Table VII-1: Projected Annual Harbor Craft Emissions With Proposed

Regulation Implementation........................................................................VII-2

Table VII-2: Projected Statewide Diesel PM Benefits of the Proposed

Regulation....................................................................................................VII-3

Table VII-3: Projected Statewide NOx Benefits of the Proposed Regulation.........VII-3
v

TABLE OF CONTENTS (cont.)

List of Tables (cont.) Page

Table VII-4: Emission Benefits from Implementation of the Proposed 

Regulation....................................................................................................VII-5

Table VII-5: Total Health Benefits Associated with Reductions in Emissions

from Commercial Harbor Craft (2009-2025)...........................................VII-8

Table VII-6: Undiscounted Unit Values for Health Effects (at various income

levels in 2006 dollars)...............................................................................VII-10

Table VIII-1: Summary of Average Cost-Effectiveness for the Period

2009-2022 ..................................................................................................VIII-2

Table VIII-2: Estimated Engine Replacement Costs ...................................................VIII-4

Table VIII-3: Estimated Useful Service and Total Life of Used Equipment.............VIII-8

Table VIII-4: Estimated Population of In-Use Vessel Engines and New Ferry

Engines Subject to Proposed Regulation Emission Limits................VIII-12

Table VIII-5: Estimated Regulation Costs for In-Use Engine Replacement ..........VIII-13

Table VIII-6: Estimated New Equipment Costs for In-Use Engine

Replacement.............................................................................................VIII-14

Table VIII-7: Population and Costs for New Ferry Propulsion Engines with

Aftertreatment ...........................................................................................VIII-15

Table VIII-8: Summary of Estimated Total Regulatory Costs for Proposed

Harbor Craft Regulation .........................................................................VIII-16

Table VIII-9: Summary of Estimated Total New Equipment Costs for Proposed

Harbor Craft Regulation .........................................................................VIII-16

Table VIII-10: Typical Affected Businesses with Change in ROE .............................VIII-18

Table VIII-11: Costs to Local, State, and Federal Agencies ......................................VIII-21

Table VIII-12: Statewide Diesel PM and NOx Annual Emission Reductions from

2009 - 2022...............................................................................................VIII-22

Table VIII-13: Statewide Diesel PM and NOx Annual Emission Reductions by

Vessel Type ..............................................................................................VIII-22

Table VIII-14: Summary of Average Cost-Effectiveness for the Period

2009 - 2022...............................................................................................VIII-23

Table VIII-15: Diesel PM Cost-Effectiveness of the Proposal and Other

Regulations/Measures (Attributes All Costs to Each Pollutant

Individually) ...............................................................................................VIII-24

Table VIII-16: Carl Moyer Program Project Completion Deadline for In-Use

Ferries, Excursion Vessels, Tugboats, and Towboats, Except

Those with Homeport in SCAQMD .......................................................VIII-25

Table VIII-17: Carl Moyer Program Project Completion Deadline for In-Use 

Ferries, Excursion Vessels, Tugboats, and Towboats, with 

Homeport in SCAQMD............................................................................VIII-26

Table VIII-18: Statewide Annual In-Use Engine Replacements ................................VIII-28
vi

TABLE OF CONTENTS (cont.)

List of Tables (cont.) Page

Table VIII-19: Statewide Annual Regulatory Costs for In-Use Repowers and

New Ferry Emission Controls.................................................................VIII-28

Table VIII-20: Statewide Annual New Equipment Compliance Costs for In-Use 

Repowers and New Ferry Emission Controls ......................................VIII-29

Table VIII-21: Statewide Annual PM and NOx Emission Reductions .......................VIII-29

Table VIII-22: Summary of Average Cost-Effectiveness for the Period

2009-2022.................................................................................................VIII-30

Table VIII-23: Additional PM and NOx Emission Reductions in the SCAQMD

with the Regulation Instead of Alternative 1 ........................................VIII-30

List of Figures Page

Figure III-1: 2004 Harbor Craft Diesel PM Emissions in California ......................... III-13

Figure III-2: 2004 Harbor Craft NOx Emissions in California.................................... III-13

Figure III-3: 2004 Vessel-Specific Diesel PM Emissions by Proximity to

Shore............................................................................................................ III-14

Figure IV-1: Estimated Diesel PM Cancer Risk from Harbor Craft Activity at the 

POLA and POLB .......................................................................................... IV-3

Figure VI-1: Estimated Numbers of Harbor Craft Engines Replaced Annually

Due to Implementation of the Proposed Regulation..............................VI-3

Figure VII-1: Projected Diesel PM Emissions With and Without the Proposed

Regulation....................................................................................................VII-4

Figure VII-2: Projected NOx Emissions With and Without the Proposed

Regulation....................................................................................................VII-4

Figure VII-3: Residential Areas Impacted by the Proposed Regulation for

Baseline Year (2004) and Projected for 2015 and 2020 at the

POLA/LB.......................................................................................................VII-6

Figure VII-4: Population Affected by the Proposed Regulation for Baseline Year

(2004) and Projected for 2015 and 2020 at the POLA/LB ...................VII-6

Figure VIII-1: Propulsion Engine Cost vs. Horsepower................................................VIII-5

Figure VIII-2: Auxiliary Engine Cost vs. Horsepower ...................................................VIII-5

Figure VIII-3: Linear Depreciation Example for Residual Value .................................VIII-7

Figure VIII-4: Ferry Main Engine Population Distribution.............................................VIII-7

Figure VIII-5: SCAQMD Annual PM Emissions ...........................................................VIII-31

Figure VIII-6: SCAQMD Annual NOx Emissions .........................................................VIII-31
I-1

I. INTRODUCTION

The California Air Resources Board’s (ARB or Board) mission is to protect public health, 

welfare, and ecological resources through the effective and efficient reduction of air 

pollutants, while recognizing and considering the effects on the economy of the State. 

The ARB’s vision is that all individuals in California, especially children and the elderly, 

can live, work, and play in a healthful environment – free from harmful exposure to air 

pollution. To achieve this, ARB has adopted numerous regulations to control emissions 

from many different sources, including diesel engines. Diesel engine exhaust is a 

health concern because it is a source of unhealthful air pollutants including gaseous and 

particulate-phase toxic air contaminants (TAC), particulate matter (PM), oxides of 

nitrogen (NOx), carbon monoxide, and hydrocarbons.

This technical support document (TSD) is an addendum to the Staff Report: Initial 

Statement of Reasons (Staff Report) and provides more detailed information supporting 

the development of the proposed regulatory action. As noted in the Staff Report, the 

proposal consists of two essentially identical regulations, one a regulation developed 

pursuant to ARB’s authority under Health and Safety Code (HSC) sections 43013(b) 

and 43018, and the other an airborne toxic control measure (ATCM) pursuant to HSC 

section 39666. Because of this, both regulations will be collecti vely referred to 

hereinafter as the “regulation” or “proposed regulation.” 

The TSD includes information on the ARB’s legal authority to adopt the proposed 

regulation, descriptions of commercial harbor craft, their uses, and the diesel engines 

used on them along with projected vessel and engine inventories, an evaluation of the 

need for emission reductions from commercial harbor craft including the corresponding 

health impacts, a summary and discussion of the proposed regulation, information 

supporting the technical feasibility of implementing the proposed regulation, the 

projected emissions reductions along with the associated reduction in health risk, and a 

discussion of the economic impact of the regulation and the corresponding economic 

analysis. 

A. Need for Proposed Regulation

In 1998, the Board identified diesel PM as a TAC with no Board-specified threshold 

exposure level. A needs assessment for diesel PM was conducted between 1998 and 

2000, which resulted in ARB staff developing and the Board approving the Risk 

Reduction Plan to Reduce Particulate Matter Emissions from Diesel-Fueled Engines 

and Vehicles (Diesel RRP) in 2000. The Diesel RRP presented information on the 

available options for reducing diesel PM and recommended regulations to achieve 

these reductions. The scope of the Diesel RRP was broad, addressing all categories of 

engines both mobile and stationary, and included control measures for all off-road 

diesel sources, such as those covered by the proposed regulation. The ultimate goal of 

the Diesel RRP is to reduce California’s diesel PM emissions and associated cancer 

risks by 85 percent from the 2000 baseline levels by 2020.
I-2

In January 2005, a Goods Movement Cabinet Workgroup, created by Governor 

Schwarzenegger and led by the California Environmental Protection Agency (CalEPA) 

and the Business, Transportation and Housing Agency, established a policy for goods 

movement and ports to improve and expand California’s goods movement industry and 

infrastructure while improving air quality and protecting public health. The workgroup 

worked collaboratively with the logistics industry, local and regional governments, 

neighboring communities, business, labor, environmental groups, and other interested 

stakeholders to create a two-phased Goods Movement Action Plan (Action Plan), which 

outlines a comprehensive strategy to address the economic and environmental issues 

associated with moving goods via the state’s highways, railways, and ports. 

In April 2006, the Board approved the Emissions Reduc tion Plan for Ports and Goods 

Movement in California as part of the Action Plan. The final phase of the Action Plan 

was completed in January 2007 and includes a framework that identifies the key 

contributors to goods movement-related emissions. The Action Plan’s emission 

reduction goals for existing harbor craft engines are 25 percent reductions for both 

diesel PM and NOx compared to baseline 2001 levels by 2010, 30 percent reductions 

compared to 2001 baseline levels by 2015, and 40 percent reduction by 2020. 

The federal Clean Air Act (CAA) requires U.S. EPA to establish National Ambient Air

Quality Standards (standards) for pollutants considered harmful to public health,

including fine particulate matter (PM2.5) and ozone. The South Coast and San Joaquin 

Valley air basins are the two areas in the State that exceed the annual PM2.5 

standards. These areas are required by federal law to develop State Implementation 

Plans (SIPs) describing how they will attain the standards by2015. The U.S. EPA 

further requires that all necessary emission reductions be achieved one calendar year 

sooner – by 2014 – in recognition of the annual average form of the standard. NOx

emission reductions are needed because NOx leads to formation in the atmosphere of 

both ozone and PM2.5; diesel PM emission reductions are needed because diesel PM 

contributes to ambient concentrations of PM2.5. San Joaquin Valley and South Coast

air basins are also in non-attainment for the federal ozone standard. However, they are 

expected to have until 2023 to attain the federal ozone standard, by invoking the 

“bump-up” provision in the CAA. The ARB and the districts are working to complete the 

PM2.5 and ozone SIPs and expect to submit them to the U.S EPA by April 2008 and 

this fall, respectively. 

While all sources of NOx emissions are important, marine vessels, which include 

commercial harbor craft engines, are one of several key contributors to PM2.5 that will 

determine whether California is able to meet the 2014 deadline for PM2.5 attainment in 

the South Coast Air Basin.

Staff is proposing a regulation to reduce diesel PM and NOx emissions from harbor craft 

vessel engines. The term ”harbor craft” includes commercial and charter fishing 

vessels, ferries, excursion vessels, tugboats, towboats, pilot vessels, crew boats, work 

boats, and other types of harbor craft. Pleasure craft and ocean-going vessels (ships) 

are not considered harbor craft, except for ocean-going tug and tow boats. 
I-3

The regulation is expected to significantly reduce emissions of diesel PM from in-use 

harbor craft engines. Diesel PM emission reductions are needed to reduce premature 

mortality, cancer risk, and other adverse health effects from exposure to this TAC. The 

regulation would achieve the 2015 and 2020 goals for harbor craft in the Goods 

Movement Action Plan. Staff projects that the regulation would reduce in-use harbor 

craft diesel PM emissions about 70 percent and NOx emissions about 60 percent from 

the 2004 baseline by 2020. These emission reductions would occur in areas along 

waterways, near ports, and in those communities surrounding these areas, as well as 

further inland. 

The regulation would also reduce diesel PM and NOx emissions that contribute to 

exceedances throughout the State of ambient air quality standards for both PM2.5 and 

ozone. These reductions would assist California in its goal of achieving state and 

federal air quality standards.

The emission reductions from the proposed regulation would result in lower ambient PM 

levels and reduced exposure to diesel PM. Staff estimates that approximately 

310 premature deaths statewide would be avoided by year 2025 from implementation of 

the proposed regulation. The estimated cost benefit of the avoided premature deaths 

and other health benefits due to the emission reductions are estimated to range from 

$1.3 to $2.0 billion.

B. Summary of Proposed Regulation

Staff is proposing a regulation that would reduce emissions of diesel PM and NOx from 

nearly 600 ferries, excursion vessels, tugboats, and towboats in the State. The 

regulation would achieve these emission reductions by requiring vessel owner/operators 

to modernize their vessels engines by installing new cleaner engines. The regulation is 

projected to reduce emissions significantly at a reasonable cost. 

The scope of the regulation includes all harbor craft operating in the State but limits the 

in-use emission reduction requirements to ferries, excursion vessels, tugboats, and 

towboats. The regulation would require all persons that operate harbor craft vessel in 

Regulated California Waters (an offshore zone that starts at the California coastline that 

is generally 24 nautical miles wide) to fuel the diesel engines with clean diesel fuel or its 

equivalent, monitor their engine operating hours (must have non-resettable hour meters 

on engines), keep records, and report certain information to ARB. Ferries, excursion 

vessels, tugboats, and towboats would be required to follow a specified engine 

replacement compliance schedule (see Chapter V). These vessels would be required 

to replace all unregulated (also referred to as “Tier 0” or “pre-Tier 1”) and Tier 1 engines 

with new, lower emitting engines meeting the current U.S. Environmental Protection 

Agency (EPA) marine engine standards. A schedule accelerated by two years is 

proposed for vessels with their homeport within the South Coast Air Quality 

Management District (SCAQMD). This provision will provide early benefits in the 
I-4

SCAQMD, which is in non-attainment for the federal annual PM2.5 and PM10 ambient 

air quality standards and 8-hour ozone standard. 

The proposed regulation would use the model year and annual hours of operation of 

each engine to determine when engines would need to be replaced. As an optional 

compliance method, an owner or operator could comply by demonstrating that the 

existing engine is as clean as the current new engine standard. Provisions are included 

to allow additional compliance time for engines that have been rebuilt to a cleaner 

standard or utilize a retrofit diesel emission control strategy. 

The proposed regulation includes requirements for newly acquired vessels and engines, 

in order to ensure that California’s harbor craft fleet becomes cleaner as vessels are 

added to the California fleet and engines are replaced. The proposed regulation would 

require that only engines meeting the U.S. EPA marine engine standards in effect at the 

time of purchase be allowed to be installed as a replacement engine on in-use harbor 

craft. In other words, a newly acquired engine would be required to meet the U.S. EPA 

standards that would apply had the engine’s model year been the same as the year it 

was purchased for the installation. Similarly, the engines on new harbor craft would be 

required to meet the standards in effect for engines with a model year that is the same 

as the date/year of vessel acquisition. Propulsion engines on new ferries, which 

contribute a significant portion of the in-harbor emissions from this source category, 

would also be required to install best available control technology (BACT). 
II-1

II. REGULATORY STATUS AND PUBLIC OUTREACH

A. Regulatory Authority

ARB has authority under California law to adopt the proposed regulation. California 

Health and Safety Code (HSC) sections 43013(b) and 43018 provide broad authority for 

ARB to adopt emission standards and other regulations to reduce emissions from new 

and in-use nonvehicular sources. Under HSC sections 43013(b) and 43018, ARB is 

directly authorized to adopt emission standards for marine vessels, as expeditiously as 

possible to meet State ambient air quality standards and to the extent permitted by 

federal law. The ARB is further mandated by California law under HSC section 39666 

to adopt airborne toxic control measures (ATCM) for new and in-use nonvehicular

sources, including commercial harbor craft, for identified toxic air contaminants such as 

diesel PM. 

Under federal and California law, ARB is the primary agency in California responsible 

for making certain that all regions of the State attain and maintain National Ambient Air 

Quality Standards (NAAQS). To achieve this, California must adopt all feasible 

measures to obtain the necessary emission reductions, including measures for mobile 

sources. The federal Clean Air Act section 209(e)(1) conclusively preempts states, 

including California, from adopting requirements for locomotive engines and new offroad engines less than 175 horsepower that are used in farm or construction 

equipment.1 However, the proposed regulation addresses off-road engines used in 

marine vessels, rather than those used in locomotives or farm or construction 

equipment. 

Under CAA section 209(e)(2), California may adopt and enforce emission standards 

and other requirements for off-road engines and equipment not conclusively preempted 

by section 209(e)(1), so long as California applies for and receives authorization from 

the Administrator of U.S. EPA. To obtain authorization, the Board must make a finding 

that the California adopted standards will be, in the aggregate, at least as protective of 

public health and welfare as applicable federal standards.2 The Administrator must 

grant a request for authorization from California unless he finds that ARB’s 

protectiveness finding is arbitrary and capricious, that California does not need the 

standards to meet compelling and extraordinary conditions, or that the standards and 

accompanying enforcement procedures are not consistent with CAA section 209. 

 

1

The California term “off-road” and the federal term “nonroad” refer to the same sources and are used 

interchangeably. In addition, for purposes of this proposed regulatory action, “nonvehicular” will also be 

used interchangeably with “offroad” and “nonroad.”

2 CAA section 209(e)(2)(A). Other states may subsequently opt into the California program, but their 

regulations must be identical to California’s requirements. CAA section 209(e)(2)(B).
II-2

B. Summary of Existing Regulations and Programs

In-use commercial diesel-fueled harbor craft are not currently subject to either California 

or federal engine emission standards. However, emissions from new harbor craft 

engines are subject to U.S. EPA new marine engine standards. These are discussed 

below.

1. U.S. EPA Marine Engine Standards

Since 1999, U.S. EPA standards have mandated the emission levels for new marine 

engines used in commercial harbor craft.3 The standards are tiered and have phased-in 

effective dates and emission levels dependent on the engine size. The size categories 

are provided in Table II-1. 

Table II-1: U.S. EPA Marine Engine Categories Used in Harbor Craft

Category Liters per Engine 

Cylinder Approximate Horsepower (hp)

Category 1 < 5.0A50B to <~2500

Category 2 5.0 to 30A>750 to <5000

A

The U.S. EPA has proposed Tier 3 and Tier 4 standards, which, if adopted, will 

update Category 1 to < 7.0 L/cyl. and Category 2 to 7.0 to 30 L/cyl.

B

The proposed Category 1 Tier 3 standards include engines rated less than 50 hp. 

All of the engines used on harbor craft in California are Category 1 or 2 engines. 

Category 1 engines are rated at less than 5.0 liters per cylinder (L/cyl) and can range as 

high as 2,500 horsepower (hp). Category 2 engines range in size from 5.0 L/cyl to 

30 L/cyl and can range from about 750 to 5,000 hp. The horsepower ranges for these 

two categories overlap. The vast majority of the engines on California harbor craft are 

Category 1 engines. According to the ARB 2004 statewide survey all of the auxiliary 

engines and about 90 percent of the propulsion engines used on California-based 

harbor craft are Category 1 engines. The remaining 10 percent of the propulsion 

engines are Category 2 engines. (ARB, 2004)

The U.S. EPA has proposed in their April 3, 2007, Draft Locomotive and Marine Notice 

of Proposed Rule Making (NPRM) to modify the breakpoint between Category1 and 2 

engines from 5.0 L/cyl to 7.0 L/cyl. (The primary purpose of the NPRM was the 

proposal of Tier 3 and Tier 4 locomotive and marine engine standards, discussed in 

more detail below.) While this change in breakpoint may reduce the number of engines 

classified as Category2 in the commercial harbor craft fleet, the largest engines used 

on commercial harbor craft, primarily tugboat propulsion engines, would still be 

Category 2 engines. Additionally, while the current Category1 definition excludes 

engines less than 50 hp, these smaller engines would be included in Category1 for 

Tier 3 standards per the NPRM. 

 

3

 Title 40, Code of Federal Regulations (CFR) Part 94.
II-3

In 1999, U.S. EPA adopted Tier 1 standards for larger Category 1 and 2 marine engines 

that were consistent with the NOx limits adopted through the International Maritime 

Organization (IMO) (IMO, 1997). These U.S. EPA NOx standards were not mandatory 

until 2004, however, through the IMO they became retroactive to 2000 once the IMO 

treaty was ratified by a majority of the participating nations. Consequently, engine 

manufacturers began manufacturing marine engines compliant with Tier 1 NOx

standards in 2000. The smallest marine engines, those less than 50 hp, were initially 

included in the U.S. EPA’s Tier 1 and Tier 2 non-road diesel engine rules and are 

subject to the same emission limits as their land-based counterparts. Tier 1 standards 

for these small engines came into effect in 1999 and 2000. Tier 1 engine standards are 

presented in Table II-2. 

Table II-2: U.S. EPA Tier 1 Standards for Marine Diesel Engines

 Used in Harbor Craft

Category Horsepower Engine

Speed

Effective 

Date

PM

(g/bhp-hr)A

NOx

(g/bhp-hr)A

NOx + HC

(g/bhp-hr)A

< 11 - 2000 0.75 - 7.8

Small 11 to < 25 - 2000 0.60 - 7.1

25 to < 50 - 1999 0.60 - 7.1

rpm = 2000 2004 - 7.3 -

130 = rpm 

<2000 2004 -

33.57Xrpm0.2 -

1 and 2 50 to <5000 

rpm <130 2004 - 12.7 -

(40 CFR Part 94) 

A Converted standards from 40 CFR 94, which are expressed in grams per kilowatt-hour (g/kW-hr), to 

grams per brake horsepower-hour (g/bhp-hr), by the following: g/kW-hr X 0.746 = g/bhp-hr

Tier 2 emission standards are presented in Table II-3. The Tier 2 standards became 

effective for engines made in 2004 to 2007, depending on size (cylinder displacement). 

The Tier 2 engine standards are about 50 percent more stringent for PM and 40 percent 

more stringent for NOx than Tier 1 standards. 
II-4

Table II-3: U.S. EPA Tier 2 Standards for Marine Diesel Engines

 Used in Harbor Craft

Category Horsepower Displacement 

(liters/cylinder)

Effective

Date

PM

(g/bhp-hr)A

NOx+ HC

(g/bhp-hr)A

< 11 - 2005 0.60 5.6

Small 11 to < 25 - 2005 0.60 5.6

 25 to < 50 - 2004 0.45 5.6

 50 to <100 < 0.9 2005 0.30 5.6

100 to <175 0.9 to < 1.2 2004 0.22 5.4

1 175 to <750 1.2 to < 2.5 2004 0.15 5.4

 >750 to 

<~2500 2.5 to < 5.0 2007 0.15 5.4

2

>750 to 

<5,000 5.0 to < 15 2007 0.20 5.8

(40 CFR Part 94) 

A Converted standards from 40 CFR 94, which are expressed in g/kW-hr, to g/bhp-hr, by the following: 

g/kW-hr X 0.746 = g/bhp-hr

As previously mentioned, the U.S. EPA’s April 3, 2007, NPRM includes proposed Tier 3 

and Tier 4 standards for Category 1 and 2 marine engines. The proposed Tier 3 

standards are presented in Table II-4.

Table II-4: Proposed U.S. EPA Tier 3 Standards for Marine Diesel Engines

 Used in Harbor Craft

Category Horsepower Displacement

(liters/cylinder)

Effective

Date

PM

(g/bhp-hr)

NOx + HC

(g/bhp-hr)

< 25 <0.9 2009 0.30 5.6

2009 0.22 5.6 25 to <100 <0.9A

2014 0.22B3.56

<0.9 2012 0.10 4.0

0.9 to <1.2 2013 0.09 4.0

1.2 to <2.5 2014 0.08C4.2

2.5 to <3.5 2013 0.08D4.2

1

100 to <4960

3.5 to <7.0 2012 0.08D4.3

2 < 4960 7 to <15 2013 0.10 4.6

(EPA, 2007) 

A

Engines less than 100 hp at or above 0.9 L/cyl. are subject to the corresponding 100-4960 hp 

standards

B Option: 0.15 g/bhp-hr PM / 4.3 g/bhp-hr NOx in 2014

C

This standard drops to 0.07 g/bhp-hr in 2018 for engines <800hp

D

This standard level drops to 0.07 in 2018 for engines <800 hp

Table II-5 presents the U.S. EPA’s proposed Tier 4 engine standards. Tier 4 standards 

would apply to engines with a maximum power rating over 800 hp. (EPA, 2007)
II-5

Table II-5: Proposed U.S. EPA Tier 4 Standards for Marine Diesel Engines

 Used in Harbor Craft

(EPA, 2007)

A Optional compliance start dates are proposed within these model years

The emission reductions projected for the proposed Harbor Craft regulation are 

dependent on the U.S. EPA promulgating Tier 3 and Tier 4 standards that are at least 

as stringent and have effective dates no later than as proposed. Earlier effective dates 

and more stringent Tier 3 standards would provide further reductions. 

The U.S. EPA’s proposed Tier 4 standards are expected to be achievable only through 

incorporating exhaust after-treatment into engine design. The U.S. EPA has proposed 

to exclude engines less than 800 hp from being subject to Tier 4 standards, based 

primarily on the space and weight limitations of smaller harbor craft. The proposed 

(ARB) regulation does not require Tier 4 standards to be met for in-use engine 

compliance due to difficulties in replacing an engine on an in-use harbor craft with one 

equipped with after-treatment systems. Consequently, this exclusion does not impact 

the reductions to be obtained through the in-use engine requirements. However, 

significant additional reductions could be obtained for new-build vessels if these Tier 4 

requirements were extended to lower horsepower ranges. 

The U.S. EPA’s 2007 NPRM discusses, but does not propose, setting rebuild standards 

for marine engines. The inclusion of rebuild standards for marine engines in U.S. EPA’s 

final rulemaking could provide substantial additional emission reduction benefits for 

California. 

2. ARB Harbor Craft Fuel Standard

In 2004, ARB adopted a fuels regulation and an ATCM that extend the applicability of 

the California standards for motor vehicle diesel fuel regulations, including a maximum 

sulfur content of 15 parts per million (ppm), to diesel fuel sold for use in commercial and 

recreational harbor craft and intrastate diesel-electric locomotives. The fuels regulation

(title 13, California Code of Regulations (CCR), section 2299) and ATCM (title 17, CCR, 

section 93116) apply to diesel fuel sold for use in commercial and recreational harbor

craft statewide. These measures became effective in SCAQMD beginning 

January1, 2006, and statewide beginning January1, 2007. Diesel fuel meeting ARB’s 

motor vehicle fuel standards is often referred to as “CARB diesel.”

Category Horsepower Effective

 Date

PM 

(g/bhp-hr)

NOx 

(g/bhp-hr)

800 to <1877 2014 0.03 1.3

1 and 2

1877 to 4960 2016A0.03 1.3
II-6

C. Environmental Justice and Public Outreach

1. Environmental Justice

The ARB is committed to integrating environmental justice principles in all of its 

activities. On December 13, 2001, the Board approved Policies and Actions for 

Environmental Justice (ARB, 2001), which formally established a framework for 

incorporating Environmental Justice into the ARB's programs consistent with the 

directive of California State law. “Environmental justice” is defined as the fair treatment 

of people of all races, cultures, and incomes with respect to the development, adoption, 

implementation, and enforcement of environmental laws, regulations, and policies. 

These policies apply to all communities in California but recognize that environmental 

justice issues have been raised more in the context of low-income and minority 

communities. 

The Environmental Justice Polices (Policies) are intended to promote the fair treatment 

of all Californians and cover the full spectrum of ARB activities. Underlying these 

Policies is a recognition that the agency needs to engage community members in a 

meaningful way as it carries out its activities. People should have the best possible 

information about the air they breathe and what is being done to reduce unhealthful air 

pollution in their communities. The ARB recognizes its obligation to work closely with all 

communities, environmental and public health organizations, industry, business owners, 

other agencies, and all other interested parties to successfully implement these Policies. 

The proposed regulation is consistent with the Environmental Justice Policy to reduce 

health risks from TACs in all communities, including those with low-income and minority 

populations, regardless of location. The proposed regulation would reduce diesel PM 

emissions from commercial harbor craft diesel-fueled engines by requiring the 

replacement of existing engines with certified Tier 2 or Tier 3 engines, whichever meets 

the U.S. EPA marine emission standards for the calendar year when compliance would 

be required. The proposed regulation also includes rebuild, retrofit, and testing options. 

The proposed regulation would provide air quality benefits for all communities 

depending upon the number of existing commercial harbor craft diesel fueled engines 

currently operating in those communities. 

The proposed regulation would significantly reduce the public’s exposure to diesel PM 

emissions and the resulting health effects, particularly for those living in communities 

nearest the ports and waterways where these vessels operate. As discussed in the 

next section, staff’s outreach efforts included public workshops and community outreach 

meetings where information was provided to the public and other stakeholders 

regarding the benefits of the proposed regulation. These included meetings at the Ports 

of Los Angeles and Long Beach. 
II-7

2. Public Outreach

During the development process, ARB staff proactively searched for opportunities to 

present information about the proposed regulation at places and times convenient to 

stakeholders. For example, meetings were held at times and locations that encouraged 

public participation. Attendees included representatives from environmental 

organizations, engine and diesel emission control associations, and other parties 

interested in commercial harbor craft diesel-fueled engines. These individuals 

participated both by providing data and reviewing draft regulations and by participating 

in open forum workshops, where staff directly addressed their concerns. Table II-6

provides information regarding meetings that were held to apprise the public about the 

development of the proposed regulation.

The ARB has held 12 public workshops and 3 community outreach meetings since 2001 

in developing this rule, as shown in Table II-6. Over 1,000 individuals and/or companies 

were notified for each workshop through a series of mailings. Notices were posted to 

ARB's diesel risk reduction and public workshops web sites and e-mailed to subscribers 

of the commercial harbor craft diesel risk reduction electronic list server. 
II-8

Table II-6: Workshop/Outreach Meeting Locations and Times

Date Meeting Type Location

March 23, 2004 Public Workshop Webcast Cal/EPA Building, 

Sacramento

May 6, 2004 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

August 5, 2004 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

December 7, 2004 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

January 14, 2005 Community Outreach Presentation Q&A PCFFA Meeting, 

Moss Landing

January 19, 2005 Community Outreach Conference Call 

Presentation Q&A

POLA PCAC AQS, 

Los Angeles

February 16, 2005 Public Workgroup Conference call Cal/EPA Building, 

Sacramento

May 17, 2006 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

June 28, 2006 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

July 27, 2006 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

September 12, 2006 Maritime AQ Technical 

Working Group Meeting Port of Long Beach 

September 13, 2006 NESCAUM Briefing Conference Call Cal/EPA Building, 

Sacramento

September 19, 2006 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

October 27, 2006 Community Outreach Presentation Q&A PCFFA Meeting, 

Bodega Bay

February 16, 2007 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

April 24, 2007 Public Workshop Toll Free

Conference Call

Cal/EPA Building, 

Sacramento

June 27, 2007 Public Workshop Toll Free

Conference Call Port of Los Angeles

In addition to the public workshops or community outreach meetings presented in 

Table II-6, ARB staff and management participated in numerous industry and 

government agency meetings over the past three years, presenting information on the 

Diesel Risk Reduction Plan and the Goods Movement Emission Reduction Plan, and 

our proposed regulatory approach for commercial harbor craft. Staff also participated in 

meetings of the California Air Pollution Control Officers Association (CAPCOA), where 

current status reports were given on the progress of the proposed regulation, and 

feedback from CAPCOA was incorporated into the proposed regulation.

As a way of inviting public participation and enhancing the information flow between the 

ARB and interested parties, staff created a diesel risk reduction program Internet web 

site (http://www.arb.ca.gov/harborcraft). Since that time, staff has consistently made 
II-9

available on the web site all related documents, including meeting presentations and 

draft versions of the proposed regulatory language. The web site has also provided 

background information on diesel PM, fact sheets, workshop and meeting notices and 

materials, and other diesel related information, and has served as a portal to other web 

sites with related information.

3. Outreach to Public Agencies

Part of the regulatory development process is the outreach to public agencies that could 

be impacted by the proposed regulation. For the proposed harbor craft regulation, ARB 

staff contacted 80 public agencies representing federal, State, county, and local 

governments. Agencies contacted include the U.S. Department of Commerce, the 

California Highway Patrol, California Department of Transportation, county sheriff’s 

departments, ports in California, and local police and fire departments. The ARB staff 

received more than 60 responses to our inquiries. Based on those responses, staff sent 

an advisory regarding the proposed regulation to over 50 responding agencies which 

could be impacted by the proposed regulation.

In addition, ARB staff used information about harbor craft operated by public agencies 

gathered through a survey of harbor craft owner operators to develop estimates of the 

potential fiscal impacts of the proposed regulation on public agencies. The agencies for 

which ARB has data include the U.S. Department of Commerce, California Department 

of Transportation, ports in California, and local agencies that operate ferries. The ARB 

staff used the engine model year, horsepower, and annual activity data associated with 

more than 60 harbor craft operated by public agencies to evaluate the potential fiscal 

impacts on public agencies. 

Outreach efforts have also included personal contacts via telephone, electronic mail, 

regular mail, surveys, facility visits, and individual meetings with other interested parties. 

These contacts have included interactions with harbor craft owners/operators, engine 

manufacturers, local and national trade association representatives, environmental and 

pollution prevention organizations, State agencies, military officials and representatives, 

and other federal agencies.
II-10

REFERENCES:

(ARB, 2001) California Air Resources Board. Policies and Actions for Environmental 

Justice; December 2001. 

(ARB, 2004) California Air Resources Board. ARB Statewide Commercial Harbor Craft 

Survey, Final Report; March, 2004. 

(EPA, 2007) U.S. Environmental Protection Agency. Draft Regulatory Impact Analysis: 

Control of Emissions of Air Pollution from Locomotive Engines and Marine 

Compression-Ignition Engines Less than 30 Liters Per Cylinder. EPA 420-D-07-001, 

March, 2007. 

(IMO, 1997) International Maritime Association, The Protocol of 1997 (Annex VI -

Regulations for the Prevention of Air Pollution from Ships), Adoption: 26 September 

1997.
III-1

III. HARBOR CRAFT INVENTORY AND EMISSIONS

This chapter provides information about commercial harbor craft operating in Regulated 

California Waters. “Regulated California Waters” include all California internal waters, 

estuarine waters, ports, and coastal waters within 24 nautical miles of the California 

coastline. Descriptions of the various types of harbor craft, a discussion of the types of 

diesel-fueled engines used in California’s harbor craft, and estimates of air emissions 

from those vessels are presented below.

Much of the information presented in this chapter was gathered as a result of an ARB 

survey of commercial harbor craft owner/operators throughout California. The ARB

conducted the survey to collect information about where the different types of harbor 

craft in the State operate, vessel activity, and engine-specific information (ARB’s 

Statewide Commercial Harbor Craft Survey, or ARB Survey) (ARB, 2004). Owners and 

operators of commercial fishing vessels, charter fishing vessels, ferries, excursion 

vessels, tugboats, towboats, crew and supply vessels, pilot boats, work, and other types 

of harbor craft were sent a copy of ARB’s survey in late 2002. The survey requested 

information about the home port, the type of vessel, if the vessel was used for 

commercial fishing, the type of fishery targeted, annual fuel use, information about 

where the vessel generally operated, and engine information (make and model of the 

engine, if it is a propulsion or auxiliary engine, horsepower, if repowered, annual hours 

of use, etc.).

The ARB Survey was sent to more than 5,000 owner/operators statewide, and ARB

received more than 700 responses representing approximately 850 vessels. For the 

purposes of developing an estimate of emissions from commercial harbor craft, ARB

staff considered and assumed the engine use information (e.g., engines size, number 

per vessel, operating time and fuel use) gleaned from the ARB Survey to be 

representative of the population of commercial harbor craft statewide. A copy of the 

ARB Survey is provided in Appendix D.

A. Harbor Craft Inventory, Descriptions, and Uses

The vessels that make up California’s harbor craft population serve a variety of 

purposes and vary in size. Each category of harbor craft makes an important 

contribution to California’s economy and well being – from fishing vessels that provide 

food to work boats that perform rescue missions at sea.

Table III-1 provides ARB’s estimate of the numbers of the various types of harbor craft 

operating in California in 2004. These estimates are based on information gathered 

from multiple data sources. Those sources included the U.S. Coast Guard, the 

California Department of Fish and Game, the ARB Survey, and information submitted 

by the Port of Los Angeles. The ARB staff chose 2004 as the base year for the harbor 

craft inventory because the most complete data was available from the different sources 

for that year. As shown in Table III-1, ARB staff estimates that in 2004 there were 

approximately 4,200 harbor craft serving various industries. Staff estimates that the 
III-2

2007 statewide harbor craft population is 3,750 vessels. The decline in vessel 

population is due to a decrease in commercial fishing vessels. 

Table III-1: 2004 Statewide Population of Harbor Craft by Vessel Type

Vessel Type Vessel PopulationA

Commercial Fishing 2,727

Charter Fishing 563

Ferries and Excursion 416

Tugboats 128

Towboats 35

Crew and Supply Boats 64

Pilot Boats 27

Work Boats 89

Other Vessels 136

Total 4,185

A

Statewide numbers of harbor craft have been estimated based 

on the 2004 baseline harbor craft emission inventory.

The following is a brief description of each of the harbor craft vessel types list in 

Table III-1. We will start by describing commercial fishing vessels and the various 

fishing methods used in California waters. 

1. Commercial Fishing Vessels

Commercial fishing vessels are diesel-fueled harbor craft dedicated to searching for and 

collecting fish for sale at market. Commercial fishing is the largest category of harbor 

craft vessels operating in California. Over 50 percent of the statewide harbor craft 

vessel population are commercial fishing vessels. A typical commercial fishing vessel 

has a single 230 horsepower (hp) propulsion engine and a single 70 hp auxiliary engine. 

However, commercial fishing vessel engines can vary greatly depending on the size 

and use of the vessel. Propulsion engines can be over 1,000 hp and auxiliary engines 

up to 300 hp. 

Commercial fishing vessels’ construction, operating characteristics (horsepower 

needed, average vessel speed, engine load, distance from shore, etc.) and fishing 

method vary with the type of fish sought. Generally, commercial fishing vessels are 

outfitted to be able to use several different fishing methods over the course of the 

fishing season. Below are descriptions of the key types of commercial fishing vessels 

operating in Regulated California Waters. The percentages of individual fishing 

methods used by commercial fishing vessels in the descriptions below are 

representative of the percentage of the total fishing fleet that use that fishing method, 

not the percentage of total time used. 
III-3

Gillnetter

Troller

Trapper (Crabber)

a. Troller

Troller vessels are one of the more common types of 

commercial fishing vessels in California. The ARB Survey 

showed that more than 50 percent of all commercial fishing 

vessels utilize trolling as a commercial fishing method. 

(ARB, 2004) Trollers tow lines with hooks on the ends and

are most often used for salmon and albacore fishing. 

(UC, 2007) The vessels vary greatly in size from small, hand 

troll skiffs to large, ocean-going troll vessels 50 feet or more

in length. (ADFG, 2007) 

b. Trapper

Trappers are used for setting pots or traps for catching fish, 

lobster, crabs, crayfish, and other similar species. These 

vessels were the second most common type of commercial 

fishing vessel reported in the ARB Survey. Approximately 

25 percent of the statewide commercial fishing fleet are 

trappers or engage in trap fishing. Trappers come in many 

shapes and sizes, from smaller vessels utilizing diesel-fueled 

outboard motors to fish near-shore waters to seagoing vessels 

of 100 feet or more in length. (ADFG, 2007) Like other 

commercial fishing vessels, trappers are often used for other 

types of fishing, such as longline and gillnet.

c. Longliner

Longliners are used primarily to catch bottomfish, such as halibut, cod, and rockfish, 

and get their name from the long lines with baited hooks that are laid on the ocean floor 

bottom. These vessels are typically between 50 to 100 feet long and can carry 20 to 

40 tons or more of iced product. (ADFG, 2007) Approximately 25 percent of 

commercial fishing vessels are used for longline fishing at various times through the 

fishing season. 

d. Gillnetter

Gillnetters typically catch salmon and a few other types of 

Fish by setting curtain-like nets perpendicular to the direction 

in which the fish are traveling. (ADFG, 2007) Some 

gillnetter vessels also function as longliners (and vice-versa) 

and operate both on the ocean and on rivers. Vessel lengths 

vary greatly; those operating in deeper waters are typically 

30 to 45 feet long. Gillnetters can comprise up to 10 percent 

of the commercial fishing activity in California.
III-4

Ferry

Purse Seiner

Trawler

e. Trawler

Not to be confused with trollers, trawlers use a 

commercial fishing method in which the vessel drags a 

cone-shaped net with a rectangular opening through the 

water to trap fish. (WCA, 2007) Trawlers are generally 

used to catch halibut and other bottomfish and make up 

approximately 10 percent of the commercial fishing 

activity in California.

f. Purse Seiner

Purse seiners make their catch using a net to encircle 

fish, such as tuna, salmon, and sardines. While vessel 

lengths vary greatly, a typical purse seiner is between 

40 and 60 feet long. Of the commercial fishing vessels 

in California, approximately 6 percent of fishing activity 

are associated with purse seiners.

2. Charter Fishing Vessels

Charter fishing vessels are similar in design to other commercial fishing vessels, except 

that they are used for hire by the general public. Charter fishing vessels are the second 

largest category of commercial harbor craft in California and make up approximately 

11 percent of the statewide harbor craft population. A typical charter fishing vessel has 

two 400 hp propulsion engines and a single 50 hp auxiliary engine. 

3. Ferry/Excursion Vessels

Ferries and excursion vessels are the third largest category of harbor craft in California. 

They make up 10 percent of the total harbor craft population. These vessels are used 

to transport people or property and are owned, controlled, operated, or managed for 

public use. The ARB Survey grouped ferries and excursion vessels together. While 

these vessels have certain similarities, there are a 

number of basic differences. Ferries are typically used 

to transport passengers. Excursion vessels are hired 

for recreation, sightseeing, and entertainment and 

include dinner cruises, diving trips, whale watching 

tours, and other similar activities. Excursion vessels 

typically have a more flexible schedule than ferries.

According to our survey, most ferries and excursion vessel have two propulsion engines 

and one auxiliary engine. The engines on ferries are usually higher horsepower than 

the engines on excursion vessels. A typical ferry has two 1,100 hp propulsion engines 

and a single 110 hp auxiliary engine. A typical excursion vessel has two 400 hp 

propulsion engines and a single 80 hp auxiliary engine. 
III-5

4. Tugboats

California’s tugboats are a relatively small part (about 3 percent) of the overall vessel 

population comprising approximately 130 vessels. Tugboats are vessels used for 

towing (and pushing) ships or other floating structures such as barges in ports, rivers, 

and harbors. Tugboats generally can be divided into three 

groups: harbor or short haul tugboats, ocean-going or long-haul 

tugboats, and barge tugboats. Ocean-going tugboats have the 

ability to haul loads along the coastline or through the open

ocean and can also be used as harbor tugboats.

Tugboats typically have two 1,300 hp propulsion engines and

two 100 hp auxiliary engines. However, newer tugboats are

being overpowered in anticipation of increases in container ship

size and the ARB survey indicated that tugboat propulsion

engines can be as large as 3,600 hp. Tugboats are the most

active vessel category based on fuel use data. Approximately

30 percent of the total fuel use for all harbor craft operating in

California is used by the tugboat fleet. (ARB, 2004) Tugboat

5. Towboats

The current towboat population is estimated to be approximately 35 vessels statewide. 

Towboats are similar in shape and function as tugboats, the primary difference being 

that towboat hulls are usually rectangular and have little freeboard (the portion of the 

side of the hull that is above the water). A typical towboat has two 500 hp propulsion 

engines and a single 80 hp auxiliary engine. However, towboat propulsion engines can 

be as large as 1,500 hp. (ARB, 2004)

6. Crew and Supply Boats

Crew and supply boats are vessels used for carrying personnel and supplies to and 

from off-shore and in-harbor locations including off-shore work platforms, construction 

sites, and other vessels. The ARB inventory estimates that there are approximately 

64 crew and supply boats operating in California. A typical crew and supply boat has 

three 450 hp propulsion engines and a single 80 hp auxiliary engine. (ARB, 2004)

7. Pilot Boats

Pilot vessels are designed to transport and transfer maritime pilots to and from oceangoing vessels. The ARB inventory estimates there are 24 pilot vessels working in the 

State. A typical pilot boat has two 400 hp propulsion engines and a single 30 hp 

auxiliary engine. (ARB, 2004) 
III-6

8. Work Boats

Work boats comprise a wide variety of vessels that 

perform duties such as fire/rescue, law enforcement, 

hydrographic surveys, training, and construction

vessels. A typical work boat has two 250 hp

propulsion engines and a single 100 hp auxiliary

engine. Engine sizes can vary significantly for work 

boats, depending on use, with propulsion engines

varying from 15 to 1300 hp. (ARB, 2004) 

9. Other Vessels

The ARB Survey also collected information on vessels classified as “other”. These 

vessels do not fit in the other eight categories. For examples, other vessel types 

include scientific research, youth training, and specialty spill response vessels. These 

vessels vary greatly in size and shape, the average engine sizes from the survey 

indicate a single 300 hp propulsion engine a single 50 hp auxiliary engine. (ARB, 2004) 

B. Marine Engines in Harbor Craft Vessels

Diesel-fueled marine engines are off-road engines marinized for use in marine 

environments. Marine engines are used as both propulsion (main) and auxiliary 

engines. Propulsion engines provide power to move a vessel through the water or 

direct the movement of another vessel. Auxiliary engines provide power for uses other 

than propulsion, such as lights, navigation and communication systems, and 

refrigeration. 

Marine engines tend to have a much longer life than their on-shore counterparts. 

According to the ARB Survey, approximately 45 percent of harbor craft propulsion 

engines were more than 20 years old and 20 percent were more than 30 years old. 

Marine engines’ long life can be attributable to a number of factors including the use of 

in-place engine rebuilds to extend the service life of existing engines and a general 

practice within the industry of safety-related engine maintenance. 

The diesel-fueled marine engines used in harbor craft vary in number of engines per 

vessel and the horsepower of the engines used. This can be seen in Table III-2. 

Ferries, tugboats, and towboats tend to have the highest horsepower engines in the 

harbor craft fleet. Commercial fishing vessels tend to have to lowest horsepower 

engines in the fleet. 

Fire Boat
III-7

Table III-2: Number of Engines and Average Engine Horsepower

for Typical Harbor Craft

Vessel Type

Typical 

Number of 

Propulsion 

Engines 

Average Hp: 

Propulsion 

Engine

Typical 

Number of 

Auxiliary 

Engines 

Average Hp: 

Auxiliary 

Engine

Commercial Fishing 1 230 0 70

Charter Fishing 2 380 1 50

Ferries and Excursion 2 730 1 90

Tugboats 2 1,300 2 110

Towboats 2 500 1 80

Crew and Supply Boats 3 440 1 80

Pilot Boats 2 410 0 30

Work Boats 2 240 0 100

Other Vessels 1 280 0 56

(ARB, 2004)

Marine engines used in California harbor craft can vary greatly in size, number of 

cylinders, and cylinder displacement. Horsepower for these engines can range from 

less than 50 hp up to 5,000 hp. Generally, these marine engines have from 3 to 

16 cylinders and the cylinder displacement can vary from less than 1 liter per 

cylinder (L/cyl) to over 10 L/cyl. 

C. Marine Engine Emission Standards

As explained in Chapter II, new marine engines have been required since 1999 to meet 

emission standards established by U.S. EPA. The U.S. EPA marine engine emission 

standards have phased effective dates and emission levels depending on the engine 

size. Table III-3 provides a summary of the U.S. EPA marine standards by engine 

categories, tier level standard, standards adoption and effective dates, and the emission 

standard range for PM and NOx pertaining to harbor craft operating in Regulated 

California Waters. More detailed information regarding the standards is available in 

Chapter II.
III-8

Table III-3: U.S. EPA Marine Engine Standards Effective Dates and Emission 

Limits for Category 1 and Category 2 Engines Used in Harbor Craft

Category Tier Level Adoption Date Effective 

Date

PM

(g/bhp-hr)A

NOx

(g/bhp-hr)A

1

IMO 1997

U.S EPA 2003

2000

2004 N/A 7.3 – 12.7B

2 U.S. EPA 1999 2004-2007 0.15-0.3 5.4-5.6E

3

U.S. EPA proposed 

2007C 2009-2114 0.08-0.3 3.5-5.6 1 E

4

D U.S. EPA proposed 

2007C 2017 0.03 1.3

1

IMO 1997 

U.S EPA 2003

2000

2004 N/A 7.3 – 12.7B

2 U.S. EPA 1999 2007 0.2 5.8E

3

U.S. EPA proposed 

2007C 2013 0.1 4.6 2 E

4

D U.S. EPA proposed 

2007C 2016-2017 0.03 1.3

(40 CFR Part 94) 

A Converted standards from 40 CFR 94, which are expressed in g/kW-hr, to g/bhp-hr, by the following: 

g/kW-hr X 0.746 = g/bhp-hr 

B

Standard is a function of engine speed, revolutions per minute (rpm). Standard=12.7 for engines with 

engine speed = 2000 rpm. Standard=7.3 for engines with engine speed =130 rpm. For engines 

between 130 and 2000 rpm, standard = 33.57 X rpm-0.2

C

Proposed U.S. EPA marine engine Standard per April 3, 2007, Draft Locomotive and Marine Notice of 

Proposed Rule Making (NPRM ).

D

Applies only to engines with maximum horsepower rating of 800 hp (600 kW) or more.

E NOx is NOx + total HC

The Tier 3 and Tier 4 standards listed in Table III-3 have been proposed by U.S. EPA 

but not yet adopted. Tier 4 standards will require aftertreatment technology to meet the 

emissions targets. The U.S. EPA has proposed Tier 4 standards only for engines with 

maximum power ratings of 800 hp and greater. 

Marine diesel-fueled engines emission standards have not kept pace with the emission 

standards for similar land-based diesel-fueled engines. The first U.S. EPA rule 

regulating new marine engines was promulgated in 1999. The first tier (Tier 1) emission 

standard in this rule did not address PM. The standards did not become mandatory 

until 2004; however, engine manufacturers voluntarily complied with these standards 

starting in 2000.4

Table III-4 illustrates how the marine engine emission standards have lagged behind 

standards for similar land–based engines. Table III–4 compares the Tier 2 emission 

standards for a 600 hp off-road (land-based) engine with the Tier 2 emission standards 

for a 600 hp marine engine. As shown in the table, the 2002 Tier 2 emission standards 

for a land-based off-road engine are 25 percent more stringent for PM and about 

 

4

 Standards were retroactive through the IMO for new engines manufactured beginning in 2000 upon the 

ratification of Annex VI. 
III-9

10 percent more stringent for NOx compared to the 2004 Tier 2 standards currently in 

effect for the same horsepower marine engine. 

Table III-4: Comparison of Tier 2 Emission Standards,

Off-road versus Marine Engines

Engine Type Horsepower Effective 

Date

PM Standard 

g/bhp-hrA

NOx Standard 

g/bhp-hrA

Off-road 600 2002 0.15 4.8

Marine 600 2004 0.20 5.4

A Grams per brake horsepower-hour 

The higher emission levels for marine engines have resulted in harbor craft engines 

becoming a significant source of air pollutant emissions in California despite the 

relatively small statewide population. This is particularly true when one considers 

coastal areas with heavy marine activities. It is estimated that emissions from harbor 

craft in the Bay Area Air Quality Management District are equivalent to almost 

60 percent of the emissions from diesel trucks in that district.5

D. Estimated Emissions from Harbor Craft

The ARB staff estimated the population of and the emissions from diesel-fueled harbor 

craft engines operating in California waters using information from the following 

sources:

• 2004 ARB survey of harbor craft owner/operators,

• emission inventories developed for the ports of Los Angeles (2001) and 

Long Beach (2002), and

• ARB’s OFFROAD model.

Baseline emission estimates of diesel PM and NOx for the year 2004 were developed

along with emission projections through 2025 based on estimates of expected growth, 

vessel engine turnover, and vessel engine age distribution. A description of the 

methodology for developing the engine inventory and associated emissions and the 

projection for future years is provided in Appendix B. 

Table III-5 provides an overview of the unregulated (Tier 0), pre-2000 emissions from 

marine diesel-fueled engines used in harbor craft. Generally, the older the engine is, 

the higher the emissions of diesel PM and NOx. Table III-5 is provided as a baseline for 

the purpose of comparison with the standards set by U.S. EPA. 

 

5

 Compared to emission estimates for heavy heavy duty diesel trucks in SIP v1.06_RF980.
III-10

Table III-5: Estimated “Tier 0” or Unregulated Marine Engine Emissions

Category Horsepower Effective

Date

PM

(g/bhp-hr)A

NOx

(g/bhp-hr)A

50 to 99 < 2000 0.32 – 0.61 4.2 – 12

100 to 174 < 2000 0.27 – 0.55 7.6 – 13

175 to 299 < 2000 0.27 – 0.55 7.6 - 13

300 to 750 < 2000 0.27 – 0.53 7.6 - 13

1 and 2

751 to < 5000 < 2000 0.27 – 0.53 7.6 - 13

(ARB, 2005) 

A Grams per brake horsepower-hour

ARB staff estimates that, based on the 2004 inventory, about 80 percent of California’s 

harbor craft engine population are Tier 0 engines with the remaining 20 percent being 

Tier 1 compliant. (ARB, 2004) Tier 2 standards were adopted in 1999 and became 

effective starting in 2004 for smaller Category 1 engines and are coming into effect 

during 2007 for larger Category 1 engines and all Category 2 engines. Since 2004, 

some of the smaller engines have been replaced with Tier 2 engines. The numbers of 

Tier 2 engines installed in California’s harbor craft population is very small at this time. 

1. Harbor Craft Vessel and Engine Populations

Table III-6 provides information about the numbers of harbor craft by vessel type and 

the number of diesel fueled engines (propulsion and auxiliary) associated with these 

vessels. As shown in Table III-6, there are approximately 8,300 diesel-fueled engines in 

about 4,200 harbor craft operating in Regulated California Waters. Of these engines, 

the majority, approximately 70 percent, are associated with fishing vessels. Engines on 

ferries and excursion vessels are the next largest category with about 15 percent of the 

engine population. 
III-11

Table III-6: 2004 Populations of Vessels and Numbers of Engines by Vessel Type

Vessel Category Numbers of 

Vessels

Numbers of 

Engines

Commercial Fishing 2,727 4,308

Charter Fishing 563 1,419

Ferries/Excursion 416 1,348

Tugboat 128 450

Towboat 35 115

Crew and Supply 64 230

Pilot 27 50

Workboats 89 158

Other 136 214

Total 4,185 8,291

ARB staff chose 2004 as the base year for the harbor craft inventory because the most 

complete data was available for that year. The initial reporting requirements in the 

proposed regulation will provide valuable information that can be used to update and 

improve the harbor craft emission inventory. In addition, the major California ports

continue to update and improve their harbor craft emission inventories. As this 

information becomes available, ARB staff intends to update the statewide emissions 

estimate for harbor craft.

As described in Appendix B, staff projected the commercial harbor craft population for

the current and future years using air districts’ fleet growth rates adjusted as appropriate 

by other available information. Because tugboats are generally over-powered and are 

capable of handling larger vessels, staff assumed tugboat fleet growth to be flat 

throughout the future years projected. The growth rate for California’s commercial 

fishing fleet was adjusted to represent the most recent fish landings (tons per year) data 

available. These data indicate that there has been a six percent per year decline in 

landings over the last decade. Since there is no way to accurately predict whether that 

trend continues indefinitely, an annual decline of six percent in the numbers of

commercial fishing vessels in California’s waters was assumed to continue through 

2009. From 2010 on, the growth was assumed flat. This decline in commercial fishing 

is the major difference between the 2007 harbor craft emissions estimate and the 2004 

emissions estimate. 

Engine population for current and future years was estimated based on the projected

vessel population, the assumption that vessels in future years would have the same 

number of engines (as shown in Table III-2) and same engine profiles as the vessels in 

the base year, along with engine attrition rates based on ARB’s OFFROAD model.

2. Baseline Emission Estimates for Diesel-fueled Harbor Craft (2004)

Appendix B provides a detailed description of the emission estimation methodology 

used to estimate emissions from harbor craft operating in Regulated California Waters. 

To estimate California statewide commercial harbor craft emissions, staff developed 
III-12

emissions rates, i.e., average emissions per engine per year, for each vessel type and 

specific region using engine activity information collected in the ARB Survey (ARB 

2004). Statewide emissions rates were determined using the engine population of each 

engine category in each region.

Data used for estimating harbor craft emissions include:

• Base year vessel and engine population

• Future fleet growth and engine turn over rates

• Engine hours of operation and engine load

• Zero-hour (new engine) emission factor

• Engine deterioration and other adjustments

• Spatial allocation of engines

ARB staff estimate that diesel-fueled harbor craft engines operating in California coastal 

and inland waters result in approximately 3.3 tons per day (tpd) of diesel PM emissions

statewide and 73 tpd of NOxin 2004. 

In addition, based on a range of statewide NOx to PM conversion factors of

0.3 – 0.5 g NH4NO3/g NOx, ARB staff estimate a secondary formation of PM2.5 nitrate 

from NOx emissions from diesel-fueled harbor craft engines ranges from approximately

22 to 36.6 tpd.

6

 Estimates of statewide 2004 diesel PM and NOx emissions from the 

different harbor craft vessel types are presented in Table III-7. 

Table III-7: Estimated 2004 Statewide Harbor Craft Emissions

2004 Pollutant Emissions, Tons/Day

Vessel Category PM NOx HC CO

Commercial Fishing 0.8 17.4 1.3 4.8

Charter Fishing 0.6 12.7 0.9 3.3

Ferries/Excursion 0.9 21.0 1.4 5.6

Tugboat 0.6 15.3 1.0 3.8

Towboat 0.1 3.0 0.2 0.7

Crew and Supply 0.1 1.4 0.1 0.4

Pilot <0.1 0.4 <0.1 0.1

Workboats <0.1 0.5 <0.1 0.1

Other 0.1 1.5 0.1 0.4

Totals 3.3 73.2 5.0 19.2

Figures III-1 and III-2 illustrate the relative shares of diesel PM and NOx emitted by 

each type of harbor craft. It is interesting to note that fishing vessels represent about 

40 percent of the diesel PM and NOx emissions, but make up 70 percent of the harbor 

craft engine population. Ferries, excursion vessels, tugboats, and towboats are 

 

6

 The conversion factor for the transformation of NOx to NH4NO3 was based on an analysis of annualaverage conversion factors for secondary formation of PM10 nitrate from NOx emissions at a number of 

urban sites in California. A more detailed description of the methodology used to evaluate the conversion 

of NOx to NH4NO3 is found in Appendix F. 
III-13

responsible for about 50 percent of the diesel PM and NOx emissions, but are only 

25 percent of the harbor craft engine population. 

Figure III-1: 2004 Harbor Craft Diesel PM Emissions in California

Diesel PM

Tugboats (0.6 tpd)

Ferries/Excursion 

(0.9 tpd)

Charter Fishing 

(0.6 tpd)

Commercial Fishing 

(0.8 tpd)

Towboats (0.1 tpd)

Work Boats 

(<0.1 tpd)

Pilot (<0.1 tpd) Other (0.1 tpd)

Crew and Supply 

(0.1 tpd)

Figure III-2: 2004 Harbor Craft NOx Emissions in California

NOx

Other (1.5 tpd)

Work Boats 

(0.5 tpd)

Pilot (0.4 tpd)

Crew and Supply 

(1.4 tpd)

Towboats (3 tpd)

Commercial Fishing 

(17.4 tpd)

Ferries/Excursion 

(21 tpd)

Tugboats (15.3 tpd)

Charter Fishing 

(12.7 tpd)
III-14

In addition to the magnitude of emissions of diesel PM and NOx from harbor craft, 

another important aspect is how close to shore the vessels operate. The ARB’s diesel 

PM risk assessment for the Ports of Los Angeles and Long Beach (ARB, 2006)

demonstrated that in-harbor emissions were responsible for greater health impacts than 

emissions that occurred outside the breakwater. Diesel PM emissions for the different 

vessel types are shown in Figure III-3. The emissions were broken up into three 

categories based on the distance from shore that the emissions occur. The three 

categories are in harbor (0 to 3 nm from the shore), between 3 to 24 nm from the shore, 

and more than 24 nm from the shore. 

Figure III-3: 2004 Vessel-Specific Diesel PM Emissions by

Proximity to Shore

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Ferry/Excursion

Tug

TowPilot

Work

Crew and Supply

Charter Fishing

Commercial Fishing

Vessel Type

Tons per Day

Harbor (0-3 nm)

3-24 nm

>24 nm

Figure III-3 shows that a majority of the ferry, excursion vessel, tugboat, and towboat 

emissions occur within the harbor and almost all emissions from these vessels occur 

within Regulated California Waters (within 24 nm). While charter and commercial 

fishing vessels are responsible for approximately 40 percent of statewide harbor craft 

emissions, only 4 percent of these emissions occur within the harbor (0-3 nm). The 

majority of fishing emissions occur in the 3 to 24 mile range, with 30 percent occurring 

more than 24 nm offshore. Thus, reducing emissions from ferries, excursion vessels, 

tugboats, and towboats would have a greater public health benefit than reducing 

emissions from all the other harbor craft categories combined.

The ARB staff also estimated district-specific emissions associated with harbor craft. 

The allocation of these estimates is based on the location of a vessel’s home port. 
III-15

Table III-8 presents a district-by-district estimate of emissions from harbor craft. Not 

surprisingly, the majority of harbor craft emissions are in coastal districts such as the 

Bay Area Air Quality Management District, the South Coast Air Quality Management 

District, and the San Diego County Air Pollution Control District.

Table III-8: Estimated 2004 Harbor Craft Emissions by District

District PM (tpd)A NOx (tpd)A

Bay Area AQMD 1.2 26.9

South Coast AQMD 0.8 18.7

San Diego County APCD 0.4 9.2

Monterey Bay Unified APCD 0.2 3.6

Ventura County APCD 0.2 3.5

Santa Barbara County APCD 0.1 2.7

North Coast Unified APCD 0.1 2.3

Yolo/Solano AQMD 0.1 1.9

San Luis Obispo County APCD 0.1 1.4

Mendocino County AQMD 0.1 1.3

Northern Sonoma County APCD 0.1 1.2

San Joaquin Valley Unified APCD <0.1 0.8

El Dorado County APCD <0.1 0.3

Placer County APCD <0.1 0.3

Totals 3.3B73.2 B

A

Emissions in tons per day (tpd)

B Numbers may not add up due to rounding

Since the allocations of harbor craft emissions in Table III-6 have been made based on 

a vessel’s home port, there are districts that may be impacted by emissions from harbor 

craft, but have no harbor craft emissions allocated to them. As more accurate data 

becomes available, the harbor craft emissions allocations will be adjusted to reflect that 

data. 

3. Projected 2015 and 2020 Emission Estimates for Harbor Craft 

Future year emissions of diesel PM and NOx were developed using information 

provided by the districts and state regulatory agencies, and annual harbor craft growth 

projections developed by ARB staff for the Goods Movement Emission Reduction Plan. 

(ARB, 2006a) The baseline emissions include the benefits of emission control 

measures that were adopted before 2007, such as ARB’s diesel fuel standards for 

commercial harbor craft and the U.S.EPA Tier 2 marine engine emission standards. 

The future year emissions projections include anticipated reductions due to the 

U.S. EPA’s proposed Tier 3 and 4 engine standards. Also included are voluntary 

emission reduction efforts by harbor craft owner/operators prior to 2005 using Carl 

Moyer Program funding. The estimates do not include the projected emission 

reductions due to implementation of this proposed measure.
III-16

In estimating baseline future year emissions, staff assumed that engines removed from 

service due to natural attrition would be replaced with engines meeting the U.S. EPA 

marine engine standards in effect at the time of engine replacement. This assumption 

may result a greater projected decline in baseline emissions than might actually occur. 

In the absence of the proposed regulation, operators would have the option of replacing 

an in-use engine with an engine that does not meet the standards in effect at the time of 

replacement, such as a used rebuilt engine. 

The resulting projected emission estimates for the years 2015 and 2020 are presented 

in Table III-9. With the exception of commercial fishing vessels, the growth rates used 

to estimate harbor craft emissions for 2015 and 2020 are the same as growth rates 

used in the Goods Movement Emission Reduction Plan. 

Table III-9: Harbor Craft Engines Projected Year 2015 and 2020

Emission Estimates

2015 Emission, Tons per Day 2020 Emission, Tons per Day

Equipment 

Types Number of 

Engines Diesel PM NOx Number ofEngines Diesel PM NOx

Commercial 

Fishing 3,163 0.4 7.8 3,163 0.2 5.6

Charter Fishing 1,516 0.3 8.2 1,570 0.2 6.6

Ferries/Excursion 1,448 1.0 21.1 1,508 0.7 16.0

Tugboat 450 0.5 11.2 450 0.4 8.0

Towboat 132 0.1 2.9 142 0.1 2.8

Crew and Supply 230 <0.1 0.8 225 <0.1 0.7

Pilot 52 <0.1 0.2 52 <0.1 0.2

Work 173 <0.1 0.2 182 <0.1 0.2

Other 237 <0.1 1.0 251 <0.1 0.9

Totals 7,400A2.3A53.5A7,542A1.7A41.1A

A Numbers may not add up due to rounding

Data provided by the Pacific Coast Fisheries Information Network shows that 

commercial fishing off the coast of California has been declining for the past few 

years. (PACFIN, 2006) It is anticipated that the downward trend will eventually stabilize, 

but it is unclear when that will occur and at what level the commercial fishing vessel 

population will be when this occurs. Because of this, ARB staff’s emission estimates for 
III-17

commercial fishing assume that the current decline in fishing (approximately 6 percent 

annually) would continue through 2009 and then remain constant into the future.

As shown in Table III-9, ARB staff is not predicting growth in the tugboat population 

despite projected growth in the goods delivered to California ports. The ARB staff 

explored the growth scenarios at ports and found several factors that play key roles in 

potential tugboat populations and emissions. First, vessel visits by ocean-going vessels 

have not been increasing from year to year. While imports of commercial goods to 

California’s ports have been increasing, vessel sizes have concurrently increased so 

that the number of port visits has remained fairly constant. Tugboat companies have 

anticipated this increase in vessel size and have been overpowering their vessels in 

anticipation of handling these larger vessels. As such, the number of tugboats 

operating at California’s ports is not expected to increase nor are the emissions from 

tugboats expected to grow. 

As can be interpreted from the projected emission estimates in Table III-9, the overall 

harbor craft engine populations are relatively stable over time, with only small growth in 

a few categories and a reduction in commercial fishing compared to the 2004 inventory. 

Emissions from harbor craft are declining due to the reduction in fishing and natural 

attrition and the subsequent replacement with cleaner new engines. However, the rate 

of those reductions is not sufficient to meet the State’s needs. As we will see in 

Chapter IV, the public health impact of the current and future emissions from harbor 

craft are a key contributor to potential cancer and non-cancer health impacts to 

Californians.
III-18

REFERENCES:

(ADFG, 2007) Gunstrom, Gary; What Kind of Fishing Boat is That? Know Your 

Commercial Fishing Boats, Parts 1 and 2; Alaska Wildlife News; 

http://www.wildlifenews.alaska.gov/index.cfm?adfg=wildlife_news.view_article&issue_id

=25&articles_id=140; July 2007.

(ARB, 2004) California Air Resources Board. Statewide Commercial Harbor Craft 

Survey Final Report; March 2004.

(ARB, 2006) California Air Resources Board, Diesel Particulate Matter Exposure 

Assessment Study for the Ports of Los Angeles and Long Beach, April 2006

(ARB, 2006a) California Air Resources Board. Emission Reduction Plan for Ports and 

Goods Movement in California; April 2004.

(PACFIN, 2006) Pacific Coast Fisheries Information Network. Personal communication. 

March 2006.

(UC, 2007) Calisphere; Trolling Gear in California – Species Caught by Trolling; 

University of California Libraries; 

http://content.cdlib.org/xtf/view?docId=kt4h4nb078&doc.view=frames&chunk.id=d0e323

&toc.depth=1&toc.id=&brand=calisphere; July 2007.

(WCA, 2007) West Coast Vancouver Island Aquatic Management Board; Fisheries 

Overview by Gear Type; http://www.westcoastaquatic.ca/fisheries_overview.htm; 

July 2007.
IV-1

IV. HEALTH IMPACTS OF CURRENT HARBOR CRAFT EMISSIONS

This chapter discusses the potential cancer and non-cancer health impacts due to the 

current level of emissions from harbor craft. For the analysis of potential cancer 

impacts, we used earlier analyses conducted as part of the Port of Los Angeles/Long 

Beach Health Risk Assessment (ARB, 2006a). For non-cancer impacts, we updated 

work done as part of the Goods Movement Emission Reduction Plan (ARB, 2006b). 

A. Potential Health Impacts of Harbor Craft Emissions

Particulate matter (PM) and NOx are the emissions of the greatest health concern from 

harbor craft. Particulate matter emitted from diesel-fueled engines (diesel PM) is used 

as the measure of the toxicity of diesel exhaust, which includes over 40 identified toxic 

air contaminants. The annual average concentration of diesel PM due to harbor craft 

emissions is used to estimate the potential cancer risk near port communities.

Non-cancer impacts are estimated based on the annual average concentration of PM. 

There are two sources of PM emissions from diesel-fueled harbor craft. The first source 

of PM is the PM directly emitted in the exhaust from diesel harbor craft engines. This is 

referred to as directly emitted diesel PM. The second source of PM is the PM that is 

formed in the atmosphere when gases emitted in the exhaust from diesel engines, 

primarily NOx and SOx, react to form PM. This is referred to as secondary diesel PM. 

Non-cancer impacts can also occur from exposures to NOx and hydrocarbon emissions 

from diesel-fueled engines. NOx and hydrocarbon emissions contribute to the formation 

of ozone, which also has associated non-cancer health impacts. 

In 1998, the Board identified PM emissions from diesel-fueled engines as a toxic air 

contaminant (TAC). The Board concluded that long-term occupational exposures to 

diesel exhaust increases the risk of developing lung cancer. The Board also concluded 

that a number of adverse long-term non-cancer effects have been associated with 

exposure, including a greater incidence of respiratory irritation and chronic bronchitis. 

Over the last several years, a substantial number of epidemiologic studies have found a 

strong association between exposure to elevated PM levels (of which diesel PM is a 

subset) and adverse non-cancer health effects. (ARB, 2002; ARB, 2006b). These noncancer health effects include premature death, increased hospitalizations for respiratory 

and cardiovascular causes, asthma and lower respiratory symptoms, acute bronchitis, 

work loss days, and minor restricted activity days. Non-cancer health effects linked to 

exposure to elevated levels of ozone include: premature deaths, hospital admissions 

for respiratory diseases, minor restricted activity days, and school absence days.
IV-2

B. Estimating Potential Cancer Impacts near California Ports 

As discussed earlier, harbor craft are used in and around ports throughout California, in 

California coastal areas and inland waterways. The diesel PM emissions from harbor 

craft engines contribute to background ambient levels of diesel PM. Based on the most 

recent emissions inventory, there are approximately 4,200 diesel-fueled harbor craft 

operating in California. Harbor craft are estimated to emit 3.3 tons per day (tpd) of 

diesel PM and 73 tpd of NOx. The increased exposure to diesel PM from diesel-fueled 

harbor craft engines may result in elevated cancer risks to people who live and work 

near California ports. 

To provide a perspective on the potential cancer risk from diesel-fueled harbor craft, 

staff used an existing analysis from 2004 on diesel PM emissions from port related 

activities (including harbor craft) at the Port of Los Angles and the Port of Long Beach. 

(ARB, 2006a) Estimates of potential cancer risks from harbor craft activity at these two 

ports would represent the upper range of cancer risks, given the magnitude of harbor 

craft emissions in the San Pedro Bay area and the proximity of the emissions to highly 

urbanized areas. Qualitative estimates of the relative impact of harbor craft emissions 

for other areas can be estimated based on a comparison of the relative magnitude of 

emissions and the proximity of the emissions to urbanized areas. For example, using 

the district emission estimates in Table III-8, one would expect that the potential cancer 

risk estimate for the Bay Area would be similar to the estimate for the ports of 

Los Angeles and Long Beach, while the cancer risk estimates for San Diego would be 

about 50 percent lower. 

The following section first discusses the cancer risks estimates for harbor craft 

operating in and around the ports of Los Angeles and Long Beach. This discussion is 

followed by a discussion of the methodology used to develop the cancer risk estimates. 

1. Cancer Risk Estimates

The ARB staff has estimated that the emissions due to harbor craft activities may result 

in health risk impacts in the nearby residential areas surrounding the ports of 

Los Angeles and Long Beach. Figure IV -1 shows the risk isopleths for diesel PM 

emissions from harbor craft at the Ports of Los Angeles and Long Beach superimposed 

on a map that covers the ports and the nearby communities. As shown in Figure IV-1, 

the area in which the risks are predicted to exceed 100 in a million has been estimated 

to be about 750 acres. For the highest risk level of over 200 in a million, the impacted 

areas have been estimated to be about 20 acres. Overall, about 77 percent of the 

effective modeling domain of 255 square miles (excluding the port property and the 

surrounding ocean area) has an estimated risk level of over 10 in a million due to the 

emissions from harbor craft. 
IV-3

Figure IV-1: Estimated Diesel PM Cancer Risk from Harbor Craft Activity at the 

POLA and POLB (Wilmington Met Data, Urban Dispersion Coefficients, 80th 

Percentile Breathing Rate, Emission = 244 TPY, Modeling Domain = 20 mi x 20 mi, 

Resolution = 200 m x 200 m)

Using the U.S. Census Bureau’s year 2000 census data, we estimated the population 

within the isopleth boundaries. Table IV-1 presents a summary of the area impacted 

and the population affected for the risk ranges of greater than 10 in a million, greater 

than 100 in a million, greater than 200 in a million, and greater than 500 in a million. 

Over 1.5 million people live in the area around the ports that has predicted cancer risks 

of greater than 10 in a million due to emissions of PM from harbor craft. Note that the 

size of the modeling domain was limited by the technical capabilities of the model. 

However, it is clear that a significant number of people outside the modeling domain are 

exposed to potential cancer risks greater than 10 in a million.

 

380000 385000 390000 395000 400000 405000

Easting (m) 

3725000

3730000

3735000

3740000

3745000

3750000

N

orthin

g (m)

0 1 2

miles
IV-4

Table IV-1: Summary of Area Impacted and Population Affected by Risk Levels

 from Harbor Craft (emission inventory based on 2002 port calls)

Risk Level Acres Impacted Population Affected

Risk > 500 0 0

Risk > 200 20 5,000

Risk > 100 75 23,000

Risk > 10 125,250 1,516,000

Note: The effective modeling domain is about 255 square miles or 163,435 acres, and the total 

population within the domain is about 2 million. The area with predicted risks greater than 10 in a 

million extends beyond the modeling domain. As such, the actual acres impacted and population 

exposed to levels greater than 10 in a million are larger than those presented in Table III-4.

Staff adjusted the potential cancer risk for the 2002 inventory to reflect the ARB 2004 

inventory for the SCAQMD. This potential risk based on the 2004 inventory provides a 

consistent baseline with which to compare the estimated risk using the projected 

controlled emissions. The adjustment to the 2004 baseline inventory increased the 

number of people exposed to a 10 in a million risk from 1.5 million to 1.7 million and the

number of acres impacted from 125,250 to a little over 140,000.. 

2. Health Risk Assessment Methodology for Cancer

Because analytical tools to distinguish between ambient diesel PM emissions from 

harbor craft and that from other sources of diesel PM do not exist, we cannot measure 

the actual concentration of diesel PM from diesel-fueled harbor craft. In place of direct 

measurements of diesel PM, we rely on a health risk assessment process to estimate 

the potential cancer risks from harbor craft emissions. A health risk assessment, as 

defined under the Air Toxics "Hot Spots" Act, includes a comprehensive analysis of the 

dispersion of hazardous substances into the environment, the potential for human 

exposure, and a quantitative assessment of both individual and population-wide health 

risks associated with those levels of exposure. 

To investigate the potential risks from exposures to the emissions from harbor craft, 

ARB staff used dispersion modeling to estimate the ambient concentration of diesel PM

from harbor craft operating at the Ports of Los Angeles and Long Beach. The key 

variables that can impact the results of a health risk assessment for harbor craft include 

the diesel PM emission rate and release characteristics (magnitude, location, and time 

of day of the emissions), the local meteorological conditions, and the length of time a 

person is exposed to the emissions. 

Diesel PM emissions are a function of the age and horsepower of the engine, the 

emissions rate of the engine, and the annual hours of operation. Older engines tend to 

have higher pollutant emission rates than newer engines, and the longer an engine 

operates, the greater the total pollutant emissions. Meteorological conditions can have 

a large impact on the modeled concentration of diesel PM, with higher concentrations 

found along the predominant wind direction and under calm wind conditions. How close 

a person is to the emissions plume and how long they breathe the emissions (exposure 
IV-5

duration) are key factors in determining potential cancer risk, with longer exposure times 

typically resulting in higher risk. 

To examine the potential cancer risks from harbor craft, ARB staff used the results of 

the 2004 health risk assessment for harbor craft operated at the Ports of Los Angeles 

and Long Beach. This analysis looked at the impacts of the 2002 estimated emissions 

for harbor craft operated at the two ports. 

Meteorological data from Wilmington was used for this study. The Wilmington site is 

about one mile away from the ports, and the measurements were collected in 2001. 

The U.S. EPA’s Industrial Source Complex Dispersion Model (ISCST3) air dispersion 

model was used to estimate the annual average offsite concentration of diesel PM in the 

area surrounding the two ports.7 The modeling domain (study area) spans a 20 by 

20 mile area, which includes both the ports, the ocean surrounding the ports, and 

nearby residential areas in which about 2 million people live. The land-based portion of 

the modeling domain, excluding the property of the ports, comprises about 65 percent of 

the modeling domain. A Cartesian grid receptor network (160 by 160 grids) with 200 by 

200 meter resolution was used in this study. While grids within the ports were included 

in the receptor network, the risks within these grids were excluded from the final risk 

analyses. The elevation of each receptor within the modeling domain was determined 

from the United States Geological Service topographic data.

The potential cancer risks were estimated using standard risk assessment procedures 

based on the annual average concentration of diesel PM predicted by the model and a 

health risk factor (referred to as a cancer potency factor) that correlates cancer risk to 

the amount of diesel PM inhaled. The methodology used to estimate the potential 

cancer risks is consistent with the Tier-1 analysis presented in the Office of 

Environmental Health Hazard Assessment (OEHHA) Air Toxics Hot Spots Program Risk 

Assessment Guidelines. (OEHHA, 2002) (OEHHA, 2003) Consistent with the OEHHA 

guidelines, we assumed that the most impacted individual would be exposed to 

modeled diesel PM concentrations for 70 years. This exposure duration represents an 

“upper-bound” of the possible exposure duration. The potential cancer risk was 

estimated by multiplying the inhalation dose by the cancer potency factor (CPF) of 

diesel PM (1.1 milligrams per kilogram body weight-days (mg/kg-d)-1).

C. Estimating Potential Non-Cancer Impact of Emissions from Harbor Craft 

Engines

To estimate the statewide potential non-cancer health impacts from harbor craft

emissions, ARB staff used the same methodology used in Appendix A of the Ports and 

Goods Movement Emission Reduction Plan (ARB, 2006b). A substantial number of 

epidemiologic studies have found a strong association between exposure to ambient 

PM2.5 and a number of adverse health effects (ARB, 2002). For this report, ARB staff 

 

7

 The U.S. EPA has promulgated the AERMOD model as the preferred air dispersion model and ISCST3 

had been phased out of use by November 2006. The ARB’s estimates of potential health risk associated 

with emissions of diesel PM at the ports of Los Angeles and Long Beach was completed in 2005. 
IV-6

quantified seven non-cancer health impacts associated with the change in exposures to 

the diesel PM emissions. Since diesel PM is a constituent of ambient PM2.5, using the 

epidemiologic study results to quantify diesel PM health effects is reasonable. The 

following section first discusses the statewide non-cancer risks estimates for harbor 

craft. This is followed by a discussion of the methodology used to develop the noncancer risk estimates. 

1. Non-Cancer Risk Estimates

Staff estimates that exposures to direct and secondary diesel PM emissions from harbor 

craft can be associated with about 90 premature deaths per year. Approximately half of 

these premature deaths are due to direct diesel PM and half from secondary diesel PM. 

All of these estimates are rounded to the tens digit. 

Using the 2004 statewide estimate of directly emitted diesel PM emissions (3.3 tons per 

day) and the association between ambient PM exposure and mortality derived from 

Pope et al. (2002), we estimate approximately 50 premature deaths (10 to 80, 95 

percent confidence interval (95% CI)) (for ages 30 and older) per year statewide can be 

associated with uncontrolled, directly emitted diesel PM from harbor craft. 

Using the 2004 statewide estimate of NOx emissions from harbor craft and the 

relationship of NOx/nitrate to PM-mortality discussed below, we estimated 

approximately 50 (10 to 80, 95% CI) premature deaths (for ages 30 and older) per year 

statewide can be associated with uncontrolled, secondary diesel PM from harbor craft. 

In addition to PM-mortality, we estimate that the 2004 estimated emissions (directly 

emitted and secondary sources) from harbor craft will result in the following non-cancer 

health impacts:

• 20 hospital admissions due to respiratory causes (10 – 30, 95% CI) 

• 40 hospital admissions due to cardiovascular causes (20 – 60, 95% CI)

• 2,400 cases of asthma-related and other lower respiratory symptoms (940 –

3,900, 95% CI)

• 200 cases of acute bronchitis (0 – 430, 95% CI)

• 16,000 work loss days (13,000 to 18,000, 95% CI)

• 90,000 minor restricted activity days (74,000 to 110,000, 95% CI)

2. Non-Cancer Health Effects Methodology

a. Primary Diesel PM

Lloyd and Cackette (2001) estimated that, based on the Krewski et al. (2000) study of 

the American Cancer Society (ACS) cohort, a statewide population-weighted average 

diesel PM2.5 exposure in the year 2000 of 1.8 μg/m3 can be associated with a mean 

estimate of 1,985 premature deaths per year in California. (Lloyd/Cackette, 2001). In 

2002, Pope et al. published new findings with the same ACS cohort based on a longer 
IV-7

follow-up time and improved statistical modeling techniques. (Pope et al., 2002) 

Consistent with U.S. EPA (EPA, 2004), ARB has been using the new PM-mortality 

relationship from Pope et al. since the adoption of the Ports and Goods Movement 

Emission Reduction Plan. Based on Pope et al. (2002), a statewide populationweighted average diesel PM2.5 exposure of 1.8 μg/m3

 can be associated with a mean 

estimate of 2,200 premature deaths per year in California, about 10% higher than 

previous estimates based on Krewski et al. (2000). The diesel PM2.5 emissions 

corresponding to the diesel PM2.5 concentration of 1.8 μg/m3 is 36,000 tons for the year 

2000 based on the emission inventory developed for this rule. 

Using this information, we estimate that reducing 17 tons per year of diesel PM2.5

emissions statewide would result in one fewer premature death. This statewide factor is 

derived by dividing 36,000 tons of diesel PM by 2,168 deaths (unrounded number of 

deaths described above). Although a single statewide factor (tons per death) is 

discussed in this example, staff actually developed basin-specific factors for the health 

impacts assessment of emissions from commercial harbor craft. These basin-specific 

factors were developed using basin-specific diesel PM concentrations and emissions for 

the year 2000. The statewide average of the basin-specific factors is somewhat lower 

than the statewide factor. 

After adjusting for population changes between 2004 and 2000 and adjusting for lower 

on-shore impacts from emissions released off-shore, staff estimates that 590 tons of 

emissions from commercial harbor craft for the year 2004 are associated with 

approximately 50 annual deaths (10 – 80, 95% CI).

8

 Estimates of other health impacts, 

such as hospitalizations and asthma symptoms, were calculated using basin-specific 

factors developed from other health studies. Details on the methodology used to 

calculate these estimates, including the adjustment for off-shore PM emissions in the 3 

to 24 nautical mile domain, can be found in Appendix A of the Emission Reduction Plan 

for Ports and Goods Movement in California (ARB, 2006b).

b. Secondary Diesel PM

In addition to directly emitted PM, diesel exhaust contains NOx, which is a precursor to 

nitrates, a secondary diesel-related PM formed in the atmosphere. Lloyd and Cackette

(2001) estimated that secondary diesel PM2.5 exposures from NOx emissions can lead 

to additional health impacts beyond those associated with directly emitted diesel PM2.5. 

(Lloyd and Cackette, 2001). To quantify such impacts, staff developed populationweighted nitrate concentrations for each air basin using data not only from the statewide 

routine monitoring network, which was used in Lloyd and Cackette (2001), but also from 

special monitoring programs such as IMPROVE and Children’s Health Study (CHS) in 

the year 1998. The IMPROVE network provided additional information in the rural 

 

8

To account for the differing impact of diesel PM emission from off-shore sources, CARB staff developed 

a South Coast and a statewide diesel PM emissions impact adjustment factor. For the South Coast, the 

adjustment factor for ship diesel PM emissions release off-shore was estimated to be 0.1, based on 

dispersion modeling. For the rest of the state, the adjustment factor was estimated to be 0.25. 
IV-8

areas, while the CHS added more data to southern California. Staff calculated the 

health impacts resulting from exposure to these concentrations and then associated the 

impacts with the basin-specific NOx emissions to develop basin-specific factors (tons 

per death). Using a similar approach as that for primary diesel PM and adjusting for 

population changes between 2004 and 1998 and adjusting for NOx to nitrate 

conversion, staff estimates that 18,000 tons of NOx emissions from commercial harbor 

craft in year 2004 are associated with an estimated 50 annual premature deaths 

(10 to 80, 95% CI). Other health effects were also estimated as outlined above.

D. Assumptions and Limitations of Health Impacts Assessment

Several assumptions were used in quantifying the health effects of PM exposure. They 

include the selection and applicability of the concentration-response functions, exposure 

assessment, and baseline incidence rates. These are briefly described below.

•For premature death, calculations were based on the concentration-response function 

of Pope et al. (2002). The ARB staff assumed that the concentration-response function 

for premature death in California is comparable to that developed by Pope and 

colleagues. This is supported by other studies (Dominici et al., 2005; Franklin et al., 

2007) in California showing an association between PM2.5 exposure and premature 

death that is similar to that reported by Pope et al. (2002). In addition, the Pope et al. 

(2002) study included subjects in several metropolitan areas of California. The U.S. 

EPA has been using the Pope et al. (2002) study for its regulatory impact analyses 

since 2004. For other health endpoints, the selection of the concentration-response 

functions was based on the most recent and relevant scientific literature. Details are in 

the Emission Reduction Plan for Ports and Goods Movement in California (ARB, 

2006b).

•The ARB staff assumed the model-predicted diesel PM exposure estimates published 

in the report titled “Proposed Identification of Diesel Exhaust as a Toxic Air 

Contaminant” (ARB, 1998) could be applied to the entire population within each basin. 

That is, the entire population within the basin was assumed to be exposed uniformly to 

modeled concentration, an assumption typical of this type of assessment.

•The ARB staff assumed the baseline incidence rate for each health endpoint was 

uniform across each county, and in many cases across each basin. This assumption is 

consistent with methods used by the U.S. EPA for its regulatory impact assessment, 

and the incidence rates match those used by U.S. EPA.

•Although the analysis illustrates that reduction in diesel PM exposure would confer 

health benefits to people living in California, we did not provide estimates for all 

endpoints for which there are concentration response functions available. Health 

effects such as myocardial infarction (heart attack), chronic bronchitis, and onset of 

asthma were unquantified due to the potential overlap with the quantified effects such 

as lower respiratory symptoms and hospitalizations. In addition, estimates of the effects 

of PM on low birth weight and reduced lung function growth in children are not 
IV-9

presented. While these endpoints are significant in an assessment of the public health 

impacts of diesel exhaust emissions, there are currently few published investigations on 

these topics, and the results of the available studies are not entirely consistent. (ARB, 

2006). In summary, because only a subset of the total number of health outcomes is 

considered here, the estimates should be considered an underestimate of the total 

public health impact of diesel PM exposure.

REFERENCES:

(ARB, 1998) Air Resources Board. Proposed Identification of Diesel Exhaust as a Toxic 

Air Contaminant, Appendix III, Part A, Exposure Assessment, April 1998.

(ARB, 2002) California Air Resources Board and Office of Environmental Health Hazard 

Assessment. Staff Report: Public Hearing to Consider Amendments to the Ambient Air 

Quality Standards for Particulate Matter and Sulfates, 2002. 

http://www.arb.ca.gov/research/aaqs/std-rs/pm-final/pm-final.htm; 

(ARB, 2006a) California Air Resources Board. Diesel Particulate Matter Exposure 

Assessment Study for the Ports of Los Angeles and Long Beach, April 2006.

(ARB, 2006b) California Air Resources Board. Emission Reduction Plan for Ports and 

Goods Movement, 2006. http://www.arb.ca.gov/planning/gmerp/gmerp.htm

(Dominici et al., 2005) Revised analyses of the National Morbidity, Mortality, and Air 

Pollution Study: mortality among residents of 90 cities. J Toxicol Environ Health A. Vol. 

68(13-14):1071-92.

(EPA, 2004) United States Environmental Protection Agency. United States 

Environmental Protection Agency, Assessment and Standards Division, Office of 

Transportation and Air Quality, Final Regulatory Impact Analysis: Control of Emissions 

from Nonroad Diesel Engines. EPA420-R-04-007. CD-ROM. Research Triangle Park, 

North Carolina, May 2004. http://www.epa.gov/nonroad-diesel/2004fr/420r04007j.pdf

(Franklin et al., 2007) Association between PM2.5 and all-cause and specific-cause 

mortality in 27 US communities. J Expo Sci Environ Epidemiol. Vol. 17: 279-287.

(Krewski et al., 2000) Krewski D.; Burnett R.; Goldberg M.; Hoover K.; Stemiatychi J.; 

Jerrett M.; Abrahamovicz M.; White W. Reanalysis of the Harvard Six Cities Study and 

the American Cancer Society Study of Particulate Air Pollution and Mortality, Health 

Effects Institute, Cambridge, Massachusetts; 2000.

http://es.epa.gov/ncer/science/pm/hei/Rean-ExecSumm.pdf

(Lloyd /Cackette, 2001) Lloyd, A.C.; Cackette, T.A.; Diesel Engines: Environmental 

Impact and Control; J Air Waste Manage. Assoc. 2001, 51: 809-847, 2001.

http://www.arb.ca.gov/research/seminars/lloyd/AWMA2001/JAWMADieselCritical

Review.pdf
IV-10

(OEHHA, 2002) Office of Environmental Health Hazard Assessment. The Air Toxics 

Hot Spot Program Risk Assessment Guidelines: Part II-Technical Support Document for 

Describing Available Cancer Potency Factors; 2002. 

(OEHHA, 2003) Office of Environmental Health Hazard Assessment. Air Toxics Hot 

Spots Program Risk Assessment Guidelines: The Air Toxics Hot Spots Program 

Guidance Manual for Preparation of Health Risk Assessments; 2003. 

(Pope, et. al., 2002) Pope CA 3rd, Burnett RT, Thun MJ, Calle EE, Krewski D, Ito K, 

Thurston GD. Lung cancer, cardiopulmonary mortality, and long-term exposure to fine 

particulate air pollution. Journal of the American Medical Association. Vol. 287 (9): 

1132-41, 2002.
V-1

V. PROPOSED CONTROL MEASURE

In this chapter, we provide a plain English discussion of the key requirements of the 

proposed regulation for diesel engines on commercial harbor craft. This chapter begins 

with a general summary of the regulation and the approach taken in developing the 

requirements in the proposal. The remainder of the chapter follows the structure of the 

proposed regulation and provides an explanation of each major requirement of the 

proposal. This chapter is intended to satisfy the requirements of Government Code 

section 11343.2, which requires that a “plain English” summary of the regulation be 

made available to the public. The proposed regulation for commercial harbor craft is 

included in Appendix A.

A. Summary of the Proposed Regulation

The proposed regulation is designed to reduce diesel particulate matter (PM) and 

oxides of nitrogen (NOx) emissions from commercial harbor craft. Emission reductions 

are achieved by establishing requirements for both new and in-use harbor craft. These 

requirements apply to any person who sells, supplies, offers for sale, purchases, owns, 

operates, leases, charters, or rents any new or in-use commercial diesel-fueled harbor 

craft that operates in California inland and coastal waters. 

For new harbor craft, the proposed regulation requires the diesel engines on-board 

harbor craft to meet the U.S. EPA marine emission standards in effect on the date of 

vessel acquisition. Because ferries are a large source of emissions, operate near urban 

centers, and carry passengers, more stringent requirements are proposed for new 

ferries. Under the proposed regulation, new ferries, in addition to installing a new 

engine, are required to install an aftertreatment system that represents Best Available 

Control Technology (BACT). 

Emission reductions from in-use ferries, excursion vessels, tugboats, and towboats 

would be achieved with the current proposal by requiring the accelerated introduction of 

cleaner diesel engines. As discussed in more detail in the next section, several 

compliance options are available to provide flexibility and reflect the diversity of diesel 

engines and vessel configurations currently in-use. 

The proposed compliance schedule for in-use engines is based on the engine model 

year and hours of operation and is designed to focus on the oldest, highest use engines 

first. Two separate compliance timelines are proposed; one for vessels with their home 

port in the SCAQMD and another for vessels with their home port outside the SCAQMD. 

At this time, these in-use requirements only apply to ferries, excursion vessels, 

tugboats, and towboats. Diesel engines on in-use ferries, excursion vessels, tugboats, 

and towboats comprise approximately 25 percent of the harbor craft engines in the 

State, yet emit more than 50 percent of the diesel PM emissions. These vessel types 

also work close to shore, operating approximately 65 percent of the time in and around 

the harbor. 
V-2

In addition, the proposed regulation includes requirements for monitoring, 

recordkeeping, and reporting. These requirements will allow staff to monitor the 

implementation of the regulation and provide more accurate estimates of the engine 

population and the associated pollution reductions

B. Discussion of the Proposed Regulation

1. Purpose

The purpose of the proposed regulation for commercial harbor craft is to reduce diesel 

PM and NOx from diesel-fueled propulsion and auxiliary engines on commercial harbor 

craft that operate in California inland and coastal waters. This regulation helps to 

implement the Goods Movement Emission Reduction Plan (GMERP) adopted by the Air 

Resources Board in April 2006. The GMERP is a comprehensive plan that identifies 

aggressive measures to reduce emissions and the associated health risk from ports and 

the movement of goods in California. This regulation will also assist in making progress 

toward meeting the State and federal ambient air quality standards for PM2.5 and 

ozone and help to fulfill State Implementation Plan emission reduction goals. 

2. Applicability

This section explains who must comply with the proposed regulation. Except for the 

exemptions described below, the proposed regulation would apply to anyone who sells, 

supplies, offers for sale, purchases, owns, operates, leases, charters, or rents any new 

or in-use diesel fueled harbor craft that operates in “Regulated California Waters”. 

“Regulated California Waters” are defined in the proposed regulation and include all 

California internal waters; estuarine waters, ports, and coastal waters within 24 nautical 

miles of the California coastline. 

To ensure there are no conflicts with existing regulations, this section also clarifies how 

this regulation relates to other regulations that could potentially apply to harbor craft 

engines. Under the proposal, the regulation for diesel engines on harbor craft would 

coordinate any requirements in existing regulations for portable engines (sections 

93116-93116.5, title 17, California Code of Regulation (CCR)) and off-road compression 

engines (sections 2420-2427, title 13, CCR) for all engines on the vessel that are 

permanently affixed to the vessel. For example, barge vessels in the State that 

currently have their engines participating in the ARB Portable Engine Registration 

Program (PERP) or a similar local air district program can continue with that program. 

On the other hand, barge vessels with engines that are permanently affixed to the 

vessel and that are not in the PERP or similar local air district program on or before 

January 1, 2009, would need to comply with this proposed regulation. Permanently 

affixed means that the engine, its fueling system, or its exhaust system is welded to the 

vessel or physically connected to the vesselor other vessel system such that the engine 

cannot be easily removed to be used in another application without modifying the 

engine. 
V-3

This section also specifies that the proposed regulation applies to ocean-going 

tugboats, and towboats as well as any tugboats or towboats pulling, pushing or hauling 

alongside tank vessels or tank barges. In addition, the proposed regulation includes 

language clarifying that the proposal does not change any applicable U.S. Coast Guard 

regulations or other applicable State or federal regulations and that vessel owners and 

operators are responsible for ensuring that they meet all applicable U.S. Coast Guard, 

State, and federal regulations. 

3. Exemptions 

The proposed regulation includes several exemptions that specify vessels that are 

exempt from the regulation due to safety or operational concerns, or because they are 

already addressed under separate regulations. The following vessels are proposed to 

be exempt from all the requirements in the regulation including the requirements for new 

and in-use harbor craft and the monitoring and reporting requirements: 

• Vessels traversing California coastal waters without stopping and without 

entering any California inland waterway or port, except in limited situations such 

as when the vessel is in distress or must stop to comply with U.S. Coast Guard 

regulations. 

• Recreational vessels that are operated primarily for pleasure. Recreational 

vessels are currently regulated under title 40, California Code of Regulations 

(CCR), section 94.

• Ocean-going vessels, except ocean-going tugboats and towboats. Ocean-going 

vessels are subject to requirements in title 13, CCR, sections 2299.1 and 93118.

• Vessel engines not permanently affixed to the vessel that are currently registered 

with the ARB’s Portable Engine Registration Program (PERP) (title 13, CCR, 

sections 2450 through 2465) and vessel engines not permanently affixed to the 

vessel that are registered with PERP on or after January 1, 2009. .

• Military tactical support vessels. These vessels must be used on a consistent 

basis for military operations globally and are exempt for homeland security 

reasons.

• All U.S. Coast Guard vessels. These vessels must be used for search and 

rescue operations, maritime law enforcement, port security and military readiness 

and are exempt for homeland security reasons. 

• Temporary emergency rescue/recovery vessels that are not ported in California 

but are brought into California to help in an emergency rescue or recovery 

operations provided that it returns to its home port at the conclusion of the 

emergency operations.

Three types of vessels are proposed to be exempt from the in-use engine compliance 

requirements, but would be subject to the monitoring, reporting, and recordkeeping 

requirements of the proposed regulation: These vessels include historic vessels, 

temporary replacement vessels, and vessels to be retired: 
V-4

• Vessels registered with the National Park Service (NPS) as “historic.” Based on 

the NPS listing of all the historic vessels in the United States, California has 

approximately 12 registered historic vessels that may be considered harbor craft. 

Requiring engine replacement could impact their historic significance. One 

example of a historic vessel is the 1907 Hercules tugboat in San Francisco. 

• Vessels that have homeports outside of California and that are brought into 

California to perform the work of a California vessel while that vessel is taken out 

of service for maintenance or repair are exempt provided that the temporary 

replacement vessel is used for less than 12 months. This exemption was 

requested by vessel fleet owners/operators with vessels both within California 

and in other locations and would allow them to use their own vessels from 

outside the State for temporary replacement of out-of-service vessels. This 

exemption requires the approval of the Executive Officer.

• California vessels that have homeports outside of the SCAQMD and that are 

brought into SCAQMD to perform the work of an SCAQMD vessel while that 

vessel is taken out of service for maintenance or repair are exempt from the 

SCAQMD engine compliance schedule, but must comply with the statewide 

schedule. The replacement time must be less than 12 months. The California 

Department of Transportation (Caltrans) requested this exemption. Caltrans 

operates ferries and work boats in both the SCAQMD and Bay Area and must 

occasionally bring a vessel from one area to the other to replace an out-ofservice vessel. This exemption requires the approval of the Executive Officer.

• Engines on a vessel that is scheduled to be retired within one year of the 

engines’ compliance date are exempt from the in-use compliance requirements 

of this regulation. However, if the vessel is not retired as scheduled, the engine 

would be in violation of this proposed regulation each day past the scheduled 

retirement date or the compliance date, whichever is later, 

An exemption from the in-use engine performance standards for low-use engines on a 

ferry, excursion vessel, tugboat, or towboat is also provided. A low-use engine is an 

engine that operates for less than 300 total annual hours of operation. In the event the 

engine operates for more than 300 hours in any given calendar year, the engine would 

be subject to the engine compliance requirements. 

Additionally, engines with less than a 50 hp maximum horsepower rating would be 

exempt from the in-use engine requirements for administrative reasons and because of 

their minimal emissions impact. 

4. Definitions

The proposed regulation provides definitions of all terms that are not self-explanatory or 

have specific meaning within the context of the proposed regulation. There are over 70 

definitions to help clarify and enforce the regulation requirements. Most of the 

definitions listed in subsection (d) of the proposed regulation were developed by staff 

with input from the public during workshops and workgroup meetings. Staff working on 

this regulation also coordinated with other ARB staff working on other diesel PM 
V-5

regulations to provide consistency where it was practical. Below, we discuss some of 

the key definitions.

Auxiliary Engine – auxiliary engines provide power for uses other than propulsion. 

Auxiliary engines are used for such as lights, navigation and communication systems, 

refrigeration, pumping fluids, dredging, and operating cranes. 

Harbor Craft – any private, commercial, government, or military marine vessel including, 

but not limited to, fishing vessels, passenger ferries, excursion vessels, tugboats, 

towboats, ocean-going tugboats and towboats, push-boats, crew vessels, work boats, 

pilot vessels, supply boats, fishing vessels, research vessels, United States Coast 

Guard vessels, hovercraft, emergency response harbor craft, and barge vessels that do 

not otherwise meet the definition of ocean-going vessels or recreational vessels.

Date of Acquisition – for a vessel engine subject to this regulation for Harbor Craft, the 

date of purchase as defined by the date shown on the front of the cashed check, the 

date of the financial transaction, or the date on the engine purchasing agreement, 

whichever is earliest. Commercial harbor craft are generally built to an customer’s 

specifications. Consequently, the date of the purchasing agreement would generally 

occur before the vessel is built. 

Homeport – the port in which a vessel is registered or permanently based.

In-Use Engine – an engine that is not a new engine. This is generally an engine that 

has been transferred to an owner or operator or has been put into service. 

In-Use Harbor Craft – a harbor craft that is not a new harbor craft. This is generally a 

harbor craft that has been transferred to an owner or operator or has been put into 

service. 

New Harbor Craft – a harbor craft built, or for which the keel was laid, on or after 

January 1, 2009 and which has never been transferred to an owner or operator. In 

cases where the equitable or legal title to the harbor craft is not transferred to an owner 

or operator until after the harbor craft is placed into service, then the harbor craft will no 

longer be new after it is placed into service. Being placed into service means that the 

harbor craft is used for its functional purposes. 

New Harbor Craft Engine – an engine manufactured or imported on or after 

January1, 2009 and which has never been transferred to an owner or operator. In 

cases where the equitable or legal title to the engine is not transferred to an owner or 

operator until after the engine is placed into service, then the engine will no longer be 

new after it is placed into service. Being placed into service means that the engine is 

used for its functional purposes. 

Temporary Replacement Vessel – a vessel whose homeport is not within California and 

is brought into California to be used in California for no longer than 12 months to 
V-6

perform the work of a California vessel that was in service and has been temporarily 

taken out of service. 

Temporary Replacement Vessel (SCAQMD) – a vessel whose homeport is not within 

the SCAQMD and is brought into the SCAQMD to be used in the SCAQMD for no 

longer than 12 months to perform the work of a SCAQMD vessel that was in service 

and has been temporarily taken out of service. 

5. Requirements

As mentioned earlier, the proposed regulation includes requirements for new and in-use 

harbor craft. Some requirements apply to all harbor craft, regardless of use and others 

apply to specific types of harbor-craft. For ease of explanation, the discussion on the 

requirements below does not follow the order of the regulation. Rather, we have

categorized the requirements discussion into three subtopics: Requirements for All 

Harbor Craft, Requirements for Newly Acquired Harbor Craft, and Operational 

Requirements for In-Use Ferries, Excursion Vessels, Tugboats, and Towboats. 

 

a. Requirements for All Harbor Craft

There are two key requirements in the regulation that apply to all harbor craft. These 

include a requirement for harbor craft to purchase only CARB diesel fuel or an approved 

alternative diesel fuel and mandatory monitoring, reporting, and recordkeeping 

requirements. 

(i) Fuel Use Requirement

The proposal’s fuel use requirement is complementary to title 13, CCR, section 2299, 

which requires that the non-vehicular diesel fuel sold for use in harbor craft meet the 

same requirements as those for California on-road diesel fuel as specified in title 13, 

CCR, sections 2281, 2282, and 2284. The Board adopted this regulatory section on 

November 18, 2004. Therefore, the fuel sellers are required to sell only fuel that meets 

13 CCR §2299. The proposed regulation would complement the existing fuel regulation 

by applying to the vessel owners and operators, rather than fuel sellers, by requiring 

owners and operators to fuel their vessels only with fuel that meets the requirements for 

California on-road diesel.

This requirement also allows the use of an approved alternative diesel fuel. Examples 

of alternative fuels that could be used are biodiesel, biodiesel blends, Fischer-Tropsch 

fuel, emulsions of water in diesel fuel, and fuels with an additive. This provision would 

also allow alternative diesel fuels and CARB diesel fuel used with a fuel additive that 

meet the requirements of the ARB Verification Procedure. 
V-7

(ii) Monitoring, Reporting, and Recordkeeping Requirements

Owners and operators of harbor craft operating in Regulated California Waters would be 

required to keep records for each vessel and install a non-resettable hour meter on 

each engine. All owners and operators of harbor craft would be required to submit an 

initial report to the ARB by February 28, 2009. The initial reporting would provide ARB 

staff with information including owner/operator contact, vessel, emission control system 

(if applicable), and engine information, including annual hours operated and location. At 

the time of initial reporting, ferry, excursion, tugboat, and towboat owners/operators 

would also be required to specify how they plan to comply with the proposed 

regulation’s in-use engine requirements. Vessel owners/operators would need to keep 

a copy of the initial reporting form and the yearly records on the vessel or in a central 

dockside location to be made available upon request of the ARB enforcement staff. 

These records include information similar to that required for the initial reporting but also 

include maintenance records. 

Additional reporting would be required if there is a change of ownership, a change of 

hours of operation, upon the purchase of new vessels or engines, and upon compliance 

with the in-use engine requirements. These reporting requirements would assist ARB in 

enforcing the regulation as well as provide information for the engine and emissions 

inventory for the development of future measures. 

Historically, harbor craft engines have not been subject to statewide or local air district 

permitting or registration programs. As a result, limited data on the marine engines 

used aboard harbor craft is available. The mandatory reporting required by the 

proposed regulation would provide more complete information on California’s harbor 

craft fleet for both implementing the current regulation and developing any further 

regulatory requirements. 

b. Newly Acquired Harbor Craft Vessels and Engines

The proposed regulation includes requirements regarding the acquisition of diesel 

engines for in-use harbor craft and the acquisition of both new and in-use harbor craft. 

These requirements apply to all types of commercial harbor craft. However, there are 

additional conditions specifically for new ferries. All of these requirements are effective 

for acquisition dates of January1, 2009 or later. 

(i) Acquisition of Engines for All In-Use Harbor Craft

Newly acquired engines for all in-use harbor craft would be required to meet the 

U.S. EPA marine emission standard in effect at the time the vessel owner acquires the 

engine. This provision assures that as older engines on in-use vessels are retired they 

are replaced with the cleanest engine available, either Tier 2 or Tier 3. These new 

engines will be both cleaner and more fuel efficient than the engines that they replace. 
V-8

The one exception to this is if the newly acquired engine was manufactured prior to 

implementation of new marine engine emission standards and is acquired by the vessel 

owner or operator no later than 6 months after the implementation date of the new 

marine standard. This allows engine retailers 6 months to sell in-stock engines after 

new standards become effective. 

Owners/operators may elect to install a Tier 3 engine on an in-use vessel as a 

replacement engine after Tier 4 marine standards come into effect. Tier 4 standards will 

require the integration of exhaust aftertreatment into the engine design, making these 

engines larger and heavier. These larger heavier Tier 4 engines may not be practical 

for engine replacements. 

(ii) Acquisition of In–use Harbor Craft Vessels

Newly acquired in-use vessels would be subject to the proposed regulation for both 

in-State and out-of-State purchases. A newly acquired in-use vessel that has been sold 

to a California party would have to comply with the non-resettable hour meter and 

reporting and recordkeeping requirements. If this vessel is a ferry, excursion vessel, 

tugboat, or towboat, the compliance schedule in Tables V-3 or V-4 would apply. 

(iii) New Harbor Craft

The engines on all new harbor craft vessels will be required to meet the U.S. EPA 

marine emission standard in effect at the time of the vessel is acquired. 

(iv) New Ferries 

Propulsion engines on new ferries would be required to be even cleaner than the Tier 2 

or Tier 3 standards require. The propulsion engines on all new ferries, with the capacity 

of more than 75 passengers, acquired after January1, 2009, will be required to install 

control technology that represents BACT in addition to an engine that meets the Tier 2 

or Tier 3 U.S. EPA marine engine standard, as applicable, in effect at the time of vessel 

acquisition. Ferry vessels can also comply with the proposed regulation by installing 

Tier 4 propulsion engines. The additional emission reductions are needed from this 

harbor craft vessel type because of the high load, high emissions, proximity to high 

population centers, and passenger exposure. 

The proposed regulation outlines an application and approval process for owners or 

operators acquiring new ferries to follow to obtain approval for the proposed BACT that 

they propose to include in the ferry design. The process outlined includes time lines for 

determination of application completeness and approval and defines the information 

required in the application. 
V-9

c. Operational Requirements for In-Use Ferries, Excursion Vessels, 

Tugboats, and Towboats

Commercial harbor craft in California comprise a wide range of vessel types and 

engines. Many of the engines installed in these vessels are older and unregulated. As 

ARB staff studied the data and worked with several owner/operators, it became 

apparent that not all harbor craft in California could be addressed with one regulation or 

one regulatory compliance option. Therefore, the focus of this proposed regulation is 

ferries, excursion vessels, tugboats, and towboats with multiple compliance options for 

these selected vessel types. Controlling in-use emissions from other vessel types may 

be addressed in future rulemakings. This proposed regulation provides several 

compliance options, including an Alternative Control of Emissions plan. By focusing on 

the oldest, highest use engines first, the proposed regulation compliance dates provide 

early removal of the highest polluting engines, and engines that are beyond their useful 

service life. 

Only in-use ferries, excursion vessels, tugboats, and towboats would be subject to 

these in-use engine operational requirements under the proposed regulation. Diesel 

engines on these vessel types are about 25 percent of the commercial harbor craft 

inventory, but produce about 50 percent of the emissions. As shown in Chapter IV, 

these vessels work close to shore a much more significant amount of time than other 

vessel types that contribute a significant portion of the emissions. Emissions released 

far offshore present a lesser health risk than near-shore emissions. Consequently, 

reducing emission from near shore sources are being addressed first. The following 

sections will explain U.S. EPA’s engine emission standard structure, the compliance 

schedules, compliance extensions, and the basic proposed regulatory approach to 

control emissions from these sources. 

(i) Emission Limits

The proposed regulation requires that in-use unregulated (Tier 0 or pre-Tier 1) and Tier 

1 propulsion and auxiliary marine diesel engines on ferries, excursion vessels, tugboats, 

and towboats meet emission limits equal to or cleaner than the U.S. EPA marine engine 

standards in effect on the compliance date specified in the proposed regulation. The 

proposed regulation also allows the harbor craft owner/operator to demonstrate that the 

current engine meets the U.S. EPA marine engine Tier 2 standard or cleaner. Once an 

engine is replaced with a Tier 2 or 3 engine or can be shown to meet the applicable 

standards, all compliance requirements for that engine will have been met. For many 

vessels, their existing engines will not be able to meet the current marine engine 

standards. Therefore, repowering the vessel with a new engine will be the most likely 

option used to meet the requirements of the regulation.

The emission limit requirements for the regulation are based on the U.S EPA Marine 

Engine Standards. The U.S. EPA Marine Engine Standards have phased effective 

dates and emission levels dependent on the engine size, e.g. the cylinder displacement, 

and maximum power rating. See Chapter II for a more detailed discussion for the 
V-10

U.S. EPA marine engine size categories and standards. Table V-1 illustrates the U.S. 

EPA engine tiers and implementation dates. 

Table V-1: U.S. EPA Marine Engine Standards and Implementation Years

U.S. EPA Tiers Effective Dates

Tier 0 (unregulated) Pre-2000

A

Tier 1 1999 - 2004

Tier 2 2004 - 2007

Tier 3B2009 - 2014

Tier 4B2014 - 2017

A

Pre-1999 for engines less than 50 hp

B

Proposed dates (EPA, 2007)

With the exception of engines less than 50 hp, all engines manufactured prior to 2000, 

are considered Tier 0 or unregulated engines. The U.S. EPA included marine engines 

less than 50 hp under the off-road Tier 1 new engine emission standards, which 

became effective in 1999. For marine engines equal to 50 hp and larger, U.S. EPA 

adopted Tier 1 limits consistent with the International Maritime Organization (IMO) 

Annex VI. These Tier 1 marine engine standards apply only to NOx+HC and became 

effective for the 2004 model year. However, engine manufacturers began complying 

with these limits starting with the 2000 model year because the IMO standards would 

become retroactive to 2000 once ratified by a majority of the participating nations. 

The U.S. EPA Tier 2 marine engine emission standards became effective for engines 

manufactured in 2004 to 2007, depending on engine size. The standards for the 

medium and smaller size engines (generally less than 750 hp) became effective in 2004 

and 2005, and the standards for the larger engines became effective in 2007. These 

Tier 2 standards are more stringent than the Tier 1 standards and include limits for PM, 

NOx+HC, and CO. 

In January 2007, U.S. EPA published a Notice of Proposed Rulemaking (NPRM) for 

Locomotive and Marine Engines. The NPRM proposes new Tier 3 and Tier 4 emission 

standards to become effective for engine model years 2009-2014 for Tier 3 and 2014 to 

2017 for Tier 4 engines. Effective dates depend on engine per cylinder displacement. 

The Tier 4 standards are proposed only for engines with maximum power ratings over 

800 hp. Staff is proposing to require only standards as stringent as Tier 3 for in-use 

engine replacement. Installing after-treatment on replacement engines to meet Tier 4 

standards could pose installation as well as safety concerns. 

The proposal’s requirements involving USEPA’s proposed Tier 3 and Tier 4 standards 

would come into effect only if USEPA finalizes and promulgates those standards as 

they were specified in the NPRM. If USEPA promulgates different Tier 3 and Tier 4 

standards, staff will need to return to the Board with a separate rulemaking to 

incorporate those Tier 3 and Tier 4 standards.
V-11

(ii) Compliance Schedule

Staff is proposing two compliance schedules for the in-use engine requirements for 

ferries, excursion vessels, tugboats, and towboats. These requirements are applicable 

to Tier 0 and Tier 1 engines on these vessel types that operate 300 hours or more 

annually. The years in which a vessel owner/operator’s engines must meet the 

proposed emissions limits are given in the compliance schedules presented in 

Table V-2 and V-3 below. Compliance dates are based on the model year of the engine 

and the hours of operation. 

The engine model year would be determined by one of three methods. In most cases, 

the engine’s actual model year of manufacture would be used to determine the required 

compliance date. However, if certain steps have been taken to reduce the emissions of 

the engine, an “effective model year” may be calculated based on the following: 

o implementing an emission control strategy that obtains at least a 25 percent 

reduction in either PM or NOx, would extend the engine model year by five 

years. This is referred to as the “Engine’s Model Year + 5” method. The date 

at which the engine must meet the U.S. EPA marine engine standards would 

be based on the engine model year plus five years;

o demonstrating that the engine has been rebuilt to Tier 1 standards or cleaner 

prior to January 1, 2008 would allow the date of rebuild to be used as the 

engine’s model year for determining when the engine must meet the U.S. 

EPA marine engine standards. This is referred to as the “Engine’s Tier 1 

Rebuild Model Year.”

Table V-2 presents the proposed Statewide schedule for compliance. This compliance 

schedule applies to all ferries, excursion vessels, tugboats, and towboats except those 

whose homeports is in the SCAQMD. The proposed compliance schedule for vessels 

whose home port is in the SCAQMD is presented in Table V-3. 

Early compliance dates, as shown in Table V-3, for the SCAQMD are necessary in 

order to provide early emission reductions from harbor craft to assist the SCAQMD in 

meeting its PM2.5 and ozone attainment goals. The SCAQMD is required to attain the 

PM2.5 standards by 2015, but must demonstrate that goals are met in 2014. NOx

emission reductions are needed because NOx leads to formation in the atmosphere of 

both ozone and PM2.5; diesel PM emission reductions are needed because diesel PM 

contributes to ambient concentrations of PM2.5. The South Coast air basin is expected 

to have until 2023 to attain the federal ozone standard by invoking the “bump-up” 

provision in the Clean Air Act. Requiring SCAQMD vessels to comply with an 

accelerated compliance schedule will result in emission reductions earlier than for the 

rest of the State. Because harbor craft can move from one area of the State to another 

to work, the proposal also addresses the situation when a vessel from outside of the 

SCAQMD is used as a temporary replacement vessel within the SCAQMD. In this 

case, the proposal exempts that vessel from the SCAQMD engine compliance schedule 

but still requires the vessel to meet the Statewide compliance schedule.
V-12

Table V-2: Compliance Dates for Vessels with Homeports Outside SCAQMD

[Note: For example, if a 1982-model year diesel engine on a tugboat operating in Regulated 

California Waters is used for 750 hours in 2011, the owner or operator must bring the engine 

into compliance with the emission standards by December 31, 2012.]

Table V-3: Compliance Dates for Vessels with Homeports in SCAQMD

[Note: For example, if a 1982-model year diesel engine on a tugboat operating in Regulated California 

Waters is used for 300 or more hours in 2009, the owner or operator must bring the engine into 

compliance with the emission standards by December 31, 2010.].

(iii) Compliance Options

Staff is proposing that in-use Tier 0 (pre-Tier 1) and Tier 1 marine engines on ferries, 

excursion vessels, tugboats, and towboats meet emission limits equal to or cleaner than 

the U.S. EPA marine engine Tier 2 or Tier 3 emission standards applicable on the 

compliance date. The proposed regulation does not require compliance with Tier 4

Engine Model Year Total Annual Hours of Operation Compliance Year

1975 and earlier = 1500 12/31/2009

1975 and earlier = 300 and <1500 12/31/2010

1976 – 1985 = 1500 12/31/2011

1976 – 1985 = 300 and <1500 12/31/2012

1986 – 1995 = 1500 12/31/2013

1986 – 1995 = 300 and <1500 12/31/2014

1996 – 2000 = 1500 12/31/2015

1996 – 2000 = 300 and <1500 12/31/2016

2001 – 2002 = 300 12/31/2017

2003 = 300 12/31/2018

2004 = 300 12/31/2019

2005 = 300 12/31/2020

2006 = 300 12/31/2021

2007 = 300 12/31/2022

Engine Model Year Total Annual Hours of Operation Compliance Year

1979 and earlier = 300 12/31/2009

1980 – 1985 = 300 12/31/2010

1986 – 1990 = 300 12/31/2011

1991 – 1995 = 300 12/31/2012

1996 – 2000 = 300 12/31/2013

2001 = 300 12/31/2014

2002 = 300 12/31/2015

2003 = 300 12/31/2016

2004 = 300 12/31/2017

2005 = 300 12/31/2018

2006 = 300 12/31/2019

2007 = 300 12/31/2020
V-13

(after-treatment based) standards for in-use engines due to issues with the additional 

weight and space requirements associated with applying after-treatment technologies to 

existing vessels. 

While we expect the primary method for compliance with the proposal is the 

replacement of in-use engines with certified Tier 2 or Tier 3 engines, the proposed 

regulation includes other options for compliance. These options include:

o demonstrating that the current engine meets the applicable U.S. EPA marine 

engine standards; 

o demonstrating that the current engine has not been operating 300 hours or 

more per calendar year and will continue to operate at this low usage rate in 

the future. 

If the engine is replaced with a Tier 2 or 3 engine, or can be shown to meet the 

applicable standards, all compliance requirements for that engine will have been met. 

The ARB staff anticipates that, in most cases, engine replacement will be the option 

chosen by vessel owners and operators to meet the proposed emission standards for 

vessels. Ferries, excursion vessels, tugboats, and towboats are good candidates for 

repowering because these vessel types have an extensive history of being repowered. 

Almost 50 ferries, excursion vessels, tugboats, and towboats statewide have been 

repowered over the last six years through the Carl Moyer Program. 

(iv) General Compliance Date Extensions

The proposed regulation also includes a provision by which the ARB Executive Officer 

may grant a vessel owner or operator a compliance extension beyond the deadline of 

the regulation. The reasons for granting an extension are: 

• a vessel is within one year of retirement,

• change of vessel hours of operationduring the year prior to the anticipated 

engine compliance date such that the effective compliance date would be 

accelerated by one year,,

• no suitable engine replacement for a particular vessel,

• delayed engine repower delivery due to the engine manufacturer, installation 

difficulties, or

• multiple vessels with engines requiring compliance within the same calendar 

year.

If an extension is required because there is no suitable engine replacement for a

particular engine, the owner or operator is required to apply for this extension at least 

six months prior to the engine regulatory compliance date. The approval process for 

this extension includes a public review and comment period.
V-14

(v) Alternative Control of Emissions (ACE)

The need for flexibility is important when considering options to reduce emissions from 

harbor craft. The proposed regulation includes an ACE option for owner/operators of 

harbor craft that would allow them to demonstrate that equivalent emission reductions 

would be achieved, or exceeded, using alternative strategies. Alternative strategies can 

include engine modifications, exhaust after-treatment control, engine repower, using 

alternative fuels or fuel additives, or fleet averaging. ACE applications must be 

approved by the Executive Officer and be made available for public review and 

comment prior to Executive Officer action. Until such approval is granted the owner or 

operator would be required to meet the performance requirements in the proposed 

regulation.

(vi) Diesel Emission Control Strategy Special Circumstances

If a diesel emission control strategy is part of an owner/operator’s compliance option 

and the diesel emission control strategy fails during or after the warranty period, then 

the owner or operator has 90 days to replace the diesel emission control strategy or 

comply with another compliance option. 

(vii) Multipurpose Harbor Craft

There are many harbor craft in the State that work as ferries, excursion vessels, and 

tugboats, and towboats and are also used as a work, crew, pilot, fishing, supply, or 

other type of vessel. If the vessel is used at any time during the year as a ferry, 

excursion vessel, tugboat, or towboat, the vessel’s engines will be required to meet the 

compliance schedule of the proposed regulation. The vessels total annual hours of 

operation will be used to determine the compliance schedule dates. 
V-15

REFERENCES:

(EPA, 2007) U.S. Environmental Protection Agency. Draft Regulatory Impact Analysis: 

Control of Emissions of Air Pollution from Locomotive Engines and Marine 

Compression-Ignition Engines Less than 30 Liters Per Cylinder. EPA 420-D-07-001, 

March, 2007. 
VI-1

VI. FEASIBILITY OF THE PROPOSED REGULATION

In this chapter, ARB staff will discuss the technical feasibility of regulatory compliance 

options available to owner/operators of ferries, excursion vessels, tugboats, and 

towboats subject to the in-use engine compliance requirements of the proposed 

regulation. The primary option by which staff expect vessel owner/operators to comply 

is engine replacement (repowering). Other options include using a diesel emission 

control strategy that reduces emissions by at least 25 percent. However, this option 

only delays the compliance date at which the engine must conform to the emission 

limits. This chapter includes short descriptions of different emission control strategies 

and several demonstration projects using different control strategies. A discussion of 

the State’s capacity for a large number of engine repowers is included along with 

information about incentive funding available to harbor craft owner/operators should 

they choose to comply with the regulation early. The chapter ends with a discussion of 

the feasibility of using BACT with new ferry propulsion engines. 

A. Repowering Vessels

The ARB staff anticipates that the majority of ferry, excursion vessel, tugboat, and 

towboat owner/operators will choose to comply with the in-use engine requirements of 

the proposed regulation by replacing (repowering) their Tier 0 and Tier 1 engines with a 

new Tier 2 or Tier 3 engine. This will result in substantial emissions improvements. 

Heavy-duty marine diesel engines currently being manufactured are significantly 

cleaner than those built just a short time ago and can provide significant PM and NOx 

benefits compared to an older engine. (Diesel, 2003) Replacing a Tier 0 marine engine 

with a Tier 2 engine provides approximately a 60 percent reduction in both PM and NOx 

emissions. Replacing with a Tier 3 engine increases this reduction to 80 percent for PM 

and 70 percent for NOx. 

The process of replacing an engine in a harbor craft takes a considerable amount of 

planning prior to actually beginning the work of replacing the engine. Harbor craft 

owner/operators must decide on replacement engines that will meet their operational 

needs; in many cases, the engine replacement plans must be reviewed and approved 

by the U.S. Coast Guard; the engine must be purchased and shipped to the facility that 

will be doing the replacement procedure; and dry dock time must be scheduled with a 

local boat repair/building facility to have the replacement done. 

Propulsion engine replacement, on average, requires about two to three weeks per 

engine. Many of these vessels have two propulsion engines so this doubles the time. 

Because propulsion engines are generally an integral part of the vessel, in many cases, 

a hole would need to be cut in the deck or side of the vessel to remove and replace the 

engine. Since new engines are typically smaller and lighter than the old engines, fitting 

the engine into the space occupied by the old engine would generally not be an issue. 

However, it may be necessary to replace the gears and the propeller shaft to 

accommodate the new engine. 
VI-2

Auxiliary engine replacement on harbor craft can be less complicated. Because 

auxiliary engines are generally more ancillary to the vessel, replacement is less 

complex and sometimes can be done without going into dry dock. While engine 

replacement is not a simple task, it has been shown to be feasible on many occasions. 

Since the inception of the Carl Moyer Program in 1998, about 400 older dirtier 

propulsion engines on harbor craft have been replaced with cleaner, newer engines. 

On the other hand, applying retrofits to marine engines presents multiple challenges 

that have yet to be fully worked out. Marine applications present a challenge due to the 

uniqueness of each application, harsh operating conditions, and safety concerns. Most 

harbor craft have unique vessel designs and retrofit devices are not available “off-theshelf” for marine installations. Rather, retrofit technologies have been custom built to fit 

a particular vessel in the few instances where retrofits have been applied.

The relatively small size of the marine retrofit market also provides less incentive for 

investments by emission control system manufacturers. Safety concerns include the 

impact of the additional weight of the emission control equipment, line of sight concerns, 

and the need for high engine reliability. While staff believes that the expanded 

development of retrofit strategies for marine applications is likely, the market is not 

sufficiently mature at this time to require retrofits for all vessels. Nevertheless, as 

discussed previously in Chapter V, the proposed regulation is designed to provide 

flexibility by allowing the use of retrofits and other engine control technologies to meet 

the proposed emission requirements provided the vessel operator can demonstrate the 

necessary emission reductions. 

B. Statewide Capacity for Engine Replacements

A key aspect to the successful implementation of the proposed regulation is the ability 

of the State’s boat yards, boat building, and boat repair facilities to accommodate the 

anticipated number of engine replacements due to the in-use engine compliance 

requirements of the proposed regulation. To evaluate the statewide capacity for engine 

replacements, ARB staff: 1) estimated the numbers of in-use engines on ferries, 

excursion vessels, tugboats, and towboats required to come into compliance with the 

emissions limits (primarily through replacement) per year using the ARB Survey 

information and engine population data from the emissions inventory; and 2) conducted 

a phone survey of boat yards, boat building, and boat repair facilities in California to 

determine the annual statewide capacity for harbor craft engine replacements. Based 

on this outreach effort, staff has determined that the number of engine replacements 

that would occur due to the proposed regulation’s compliance schedule would be 

achievable considering the State’s capacity. Below, more details are provided on ARB 

staff’s approach and findings pertaining to the statewide capacity for engine 

replacements.

The numbers of both auxiliary and propulsion engine replacements anticipated per year 

are shown in Figure VI-1. An average of 128 replacements of both auxiliary and 

propulsion engines per year are anticipated over the 14-year compliance period. Of the 
VI-3

128 engine replacements, over 60 percent, or about 80 engines, are propulsion engine 

replacements. Because auxiliary engine replacements are less involved and do not 

necessarily require a dry dock facility, staff assumed dry docking for the propulsion 

engine replacements would be the limiting factor for the State’s capacity. While the 

14-year average for propulsion engine replacement is 80 engines, the maximum 

number of propulsion engine repowers required in one year (2015) is estimated to be 

about 150. The next highest estimate is 140 engines in 2010 followed by a four-year 

period from 2017–2020 with about 120 engines each year. 

Figure VI-1: Estimated Numbers of Harbor Craft Engines Replaced Annually 

Due to Implementation of the Proposed Regulation

To determine if there is sufficient capacity to handle the potential business generated by 

the implementation of the proposed regulation, ARB staff conducted a telephone survey 

of more than 50 boat yards, boat builders, and boat repairers throughout California. 

(ARB, 2007) These facilities provide marine engine rebuilds, overhauls, scheduled and 

emergency maintenance, as well as engine replacements. All the facilities were active 

businesses. These facilities generally schedule jobs a minimum of three or four weeks 

in advance. At the time ARB staff contacted them in May 2007, most were booked 

through the summer months. In the phone survey, staff collected information on where 

the business was located, whether or not the business performed engine replacements, 

0

50

100

150

200

250

300

2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

Year

Numbers of Engines

Propulsion

Auxiliary
VI-4

any size limitations on the vessels serviced, and the estimated numbers of engines 

replaced annually. 

Based on this survey and as shown in Table VI-1, staff estimates that the total statewide 

capacity for engine repowers ranges from about 220 to 270 per year. 

Table VI-1: Statewide Engine Replacement Capacity

Region of the State Numbers of Engines (per year)

Northern California 76 – 101

Los Angeles 93 – 110

San Diego 48 – 60

Total Capacity Statewide 217 – 271

Additional information on statewide capacity for harbor craft engine replacements can 

be inferred from the implementation of the Carl Moyer Program. Over the past 6 years, 

an annual average of about 65 to 70 marine propulsion engines have been replaced 

through incentive funding provided by the State’s Carl Moyer Program. Based on the 

survey data above, these represent about 25 to 30 percent of the estimated State 

capacity. 

Some of the engine replacement could also occur in place of an operator’s normal 

vessel maintenance activities that would occur in dry dock such as engine rebuild, 

overhaul, or some other maintenance during the year, or in the next few years. This 

would have the effect of increasing the available capacity. Staff also anticipate that 

some vessel owner/operators will replace their engines early in order to be eligible for 

incentive funding. These voluntary early repowers would shift the distribution of 

repowers and more evenly distribute the workload on the industry. 

Based on these findings, ARB staff believes that California’s boat yards, boat builders, 

and boat repairers currently have the capacity to absorb the numbers of engine 

replacements that would result from the implementation of the proposed regulation. At 

the same time, staff believe that the proposed compliance schedule is the upper bound 

for marine engine replacements, and implementing a compliance schedule that would 

increase the numbers of marine engine repowers in a given year would over-extend the 

capacity of California’s boat yards, boat builders, and boat repairers to provide quality 

service in a timely manner. 

The ARB staff will be doing additional outreach to California’s boat yards, boat builders, 

and boat repairers to keep them abreast of the status of the proposed regulation. 

Outreach will allow California’s boat yards, boat builders, and boat repairers to prepare 

for the additional business resulting from the implementation of the proposed regulation.
VI-5

C. Grant Funding Availability

The use of incentive and grant programs can play an important role in reducing 

emissions from harbor craft. Under the proposed regulation, vessel operators can 

continue to leverage grant monies provided they meet the criteria for the funding 

program. In most cases, an operator will need to comply with the regulation earlier than 

required to be eligible for funding. The following paragraphs discuss three 

incentive/grant funding sources that may be available to vessel owner/operators. More 

information on grant funding and the economic impacts of the proposed regulation are 

provided in Chapter VII. 

1. Federal Grants

The Federal Transit Authority (FTA) has provided a number of California-based publiclyfunded ferry operations with funding grants in the recent past. The FTA has provided 

approximately 77 million dollars in grant funding to five California-based publicly-funded 

ferry operations.

The FTA makes grant funding available to public agencies that have legal authority to 

receive and dispense federal funds. The recipients of the grant funding are responsible 

for managing their projects in accordance with Federal requirements. (FTA, 2007)

2. The Carl Moyer Memorial Air Quality Standards Attainment Program

Repowering harbor craft has been on-going throughout the State under the auspices of 

California’s Carl Moyer Memorial Air Quality Standards Attainment Program (Moyer) for 

eight years. As of the 2003-2004 fiscal year, about 400 propulsion and 50 auxiliary 

engines had been replaced in approximately 300 harbor craft. The types of vessels that 

have participated in the Moyer program are representative of all types of harbor craft; 

ferries and excursion vessels, tugboats, towboats, commercial fishing vessels, charter 

fishing vessels, and others.

The Moyer Program provides funds on an incentive basis for the incremental cost of 

cleaner than required engines and equipment which result in significant near-term 

reductions in NOxand PM emissions. Marine vessel repowers in the Moyer Program 

are required to achieve a minimum of a 15 percent reduction in NOx emissions to be

eligible for funding. The average engine replacement cost was approximately $100,000 

and the average Moyer contribution per engine was approximately $54,000. Emission 

reductions from marine vessels achieved through Moyer in the first seven years totaled

1,250 tons per year of NOx and 75 tons per year of PM at a NOx-weighted average cost 

effectiveness of $1,800 per ton. (ARB, 2006)

3. California Goods Movement Bonds

In November 2006, California voters approved Proposition 1B which, when 

implemented, would provide $1 billion in incentive funding to reduce emissions from 
VI-6

goods movement activities. Enabling legislation is required before these funds can be 

made available to ARB, and may provide additional direction regarding fund project 

categories and funding recipients. Some of these funds may become available to 

harbor craft involved in goods movement activities. 

D. Alternative Emission Control Strategies

The proposed regulation allows for alternatives to engine replacement to meet the 

requirements to reduce emissions of diesel PM and NOx from harbor craft. For 

example, an operator can chose to demonstrate that the vessel engines meet the 

applicable U.S. EPA Marine Engine Standard through the application of retrofit control 

devices or engine modifications. In addition, an operator can chose to install an 

emissions control strategy that reduces PM or NOx by a minimum of 25 percent. 

Implementing an alternative emission control strategy that reduces emissions by 

25 percent, however, does not exempt a harbor craft owner/operator from ultimately 

meeting the U.S. Marine Engine Standards, rather, this option provides for a 5-year 

compliance extension. 

The alternatives available to a harbor craft owner/operators range from aftertreatment 

controls to engine modifications. While many control technologies have been proven to 

reduce emissions of PM and NOx from land-based diesel-fueled engines, there is 

limited experience in applying these to harbor craft. In addition, to date, there are no 

emission control strategies verified by the ARB for marine applications. 

Several factors impact the selection of an alternative emission control strategy including 

the engine’s duty cycle, the exhaust system configuration, the placement of the engine 

in the hull, the weight of the proposed emission control strategy, and engine age. In 

addition, any design modification must be approved by the U.S. Coast Guard prior to 

changes being made. 

Table VI-2 provides general descriptions of diesel PM and NOxemission reduction

control strategies that have been used in diesel applications. A brief description of 

demonstration projects where the technology has been applied in the marine 

environment is also included. Additional discussion on selected demonstration projects 

if provided in Section E of this chapter. For more information on the various control 

technologies and demonstration projects, the reader is directed to Appendix E. 
VI-7

Table VI-2: Alternative Marine Application Emission Control Strategies

Potential Emission 

Control Technology Brief Description Reductions

Diesel PM NOx

Demonstration Projects

Diesel Particulate Filters (DPF)

Removes PM through physical 

filtration. Most common type is “wallflow” filter - exhaust gas forced to flow 

through porous channel walls due to 

blocked channel ends

85% 0%

One project to date, a DPF was 

installed on an auxiliary engine of a 

ferry. Emission testing results have not 

been provided.

Diesel Oxidation Catalysts (DOC)

Aftertreatment with catalytic surfaces 

that enhance the combustion of 

carbonaceous pollutants

25% 0%

There is anecdotal evidence that DOCs 

have been installed on excursion 

vessels in Europe with some success. 

No specific data available. 

Flow-through Filters (FTF )

Densely packed material that either

traps PM or causes turbulent exhaust 

flow to enhance combustion of 

unburned hydrocarbons 

50–75% 0%

One installation on a work boat with 

400 hp Detroit Diesel propulsion 

engines. Emission testing results 

available. 

Selective Catalytic Reduction 

(SCR)

Injects ammonia or urea into the 

exhaust, in the presence of a catalyst, 

to reduce NOx to nitrogen and water

0% 50–85%

SCR has been used in European ferries 

for a number of years. There has been 

an installation on a ferry in New York 

City. The ferry has two 1,500 hp 

Caterpillar engines. The SCR has been 

installed and working since 2005. Here 

in California, SCR was installed on a 

catamaran ferry with two MTU/DDC 

3,100 hp engines. Recent information 

indicates this application has issues that 

need to be addressed.

Water/Fuel Mixture

Water absorbs heat in the combustion 

chamber. This reduces the peak 

combustion temperature and, in turn, 

reduces NOx formation

0%

One-to-one 

water to NOx

up to 20% 

water

One installation on a ferry with 1,000 hp 

Detroit Diesel propulsion engines. 

Emission testing results available. 

Humidify Intake Air/ Water Injection 

at Air Intake

Water absorbs heat in the combustion 

chamber, reducing the peak 

combustion temperature which 

reduces NOx formation

0% 15–25%

Humid Air system tested on high speed 

hydrofoil ferry – 1050 hp engines. 

Water injection tested on Tier 0, 360 hp, 

ferry engine. 
VI-8

Table VI-2: (cont.). Alternative Marine Application Emission Control Strategies

Potential Emission Reductions

Control Technology Brief Description

Diesel PM NOx

Demonstration Projects

Engine Rebuild Kits

An engine will be rebuilt from the block 

up with new pistons, rings, etc. with 

modifications to increase combustion 

efficiency and/or reduce pollutants

40% 35%

Engine rebuild kits have been 

installed on tugboat EMD engines. 

No specific data available. 

Clean Cam

Engine rebuild technology, includes a 

proprietary cam shaft, cylinder liners, 

and turbo charger modification. The new 

cam provides an opportunity for residual 

exhaust gas to absorb heat and reduce 

combustion temperatures thereby 

reducing NOx formation

30% - Benefit 

dependent on the 

horsepower of 

the engine

70% - Benefit 

dependent on 

the horsepower 

of the engine

One installation on a work boat with 

400 hp Detroit Diesel propulsion 

engines. The Clean Cam 

technology is specific to Detroit 

Diesel Series 71 engines. Emission 

testing results available.

ECOTIP Fuel Injectors

Provides more consistent fuel injection 

pressure and minimizes the amount of 

fuel entering the combustion chamber 

after the fuel injection cycle

 40% 0%

ECOTIP fuel injectors have been 

installed on tugboat s. No specific 

data available.

Alternative Fuels Impacts on emissions depend on the fuel 

type Fuel Dependent Fuel Dependent

One demonstration of the potential 

of biodiesel in the marine sector. 

Biodiesel, B20 and B100, was used 

on a ferry prior to engine 

replacement. A report of the results 

available. 

Fuel Cells

Converts chemical energy to electricity 

by combining oxygen from the air with 

fuel

100% 100%

No fuel cells are currently in-use in 

marine applications. The WTA plans 

to include fuel cell technology as the 

auxiliary engine in a future vessel. 

Exhaust Gas Recirculation 

(EGR)

Reduces the combustion temperatures in 

the combustion chamber by diluting the 

mixture in the chamber. Reduced 

combustion temperatures reduces NOx

formation

PM disbenefit

50-300% 15-50%

To date, there have been no 

demonstrations of this technology 

with a marine application.
VI-9

E. In-Use Experience with Diesel Emission Control Strategies

1. Demonstration Projects

There have been a number of demonstration projects nationwide funded primarily 

through public agencies to implement installation of aftermarket emission controls for 

harbor craft. Brief discussions of some of these demonstration projects are presented 

below.

a. Diesel Particulate Filter on U.S. Navy Workboat

In 2006, one of two DDC 12V-71 400 horsepower engines on a U.S. Navy workboat 

operating in the Suisun Bay was rebuilt with Clean Cam Technology (CCT) system, 

including combustion chamber and injector modifications and the addition of a 

turbocharger. Based on preliminary emissions tests results, the rebuilt engine reduced 

PM emissions by over 30 percent and NOx emissions by approximately 70 percent. A 

Rypos active flow-through DPF was tested on the engine before it was rebuilt with CCT. 

This filter achieved a PM reduction of approximately 70 percent and a small NOx 

reduction. Used together, the CCT and Rypos active DPF achieved over 80 percent 

PM reduction and over 70 percent NOx reduction. Durability testing of the system was 

completed in late 2006.

This is project is a prime example of the uniqueness associated with the installation of 

marine-related aftertreatment controls. The DPF was engineered specifically for the 

space available below deck, the average engine load, and the size of the engines 

powering the vessel. In addition, modifications were made to the vessel’s exhaust 

system to ensure that there would be no intrusion by salt water into the system.

This demonstration shows that DPFs are a technology that has the potential for wider 

marine applications if steps are taken to ensure that the control device is sized 

appropriately and any unique feature of the vessel design or operation is addressed in 

the system’s design. 

b. Selective Catalytic Reduction

(i) Vallejo Baylink Ferry

In 2004, the Vallejo Baylink Ferry launched M/V Solano, a low emissions ferry utilizing a 

urea-based SCR system made by Steuler GmBH. This system was based on an SCR 

designed for stationary sources. This ferry is part of the passenger ferry system which 

services Vallejo and the North San Francisco Bay. The SCR system was used with the 

two MTU/DDC 16V-4000 propulsion engines with rated power of 3100 hp each. The 

SCR system was designed to reduce NOx by 57 percent. (Baylink, 2006; MARAD, 

2003)
VI-10

In July of 2007, engine alarms indicating high cylinder temperature were set off in the 

MV Solano’s propulsion engines. BayLink staff inspected the engine and the SCR unit. 

They found that a number of the starboard engine cylinders showed excessive wear as 

well as ring damage. Upon opening up the starboard SCR unit, they found extensive 

damage to the catalyst blocks. The catalyst block damage included what appeared to 

be salt water corrosion and excessive heat and mechanical impacts. The BayLink staff 

have published a report and continue to look into the potential reasons for the damage 

to the engine and the SCR unit. (BayLink, 2007) 

(ii) Staten Island Ferry

The two Caterpillar 3516 1,550 horsepower propulsion engines of the M/V Alice Austen 

were retrofitted with SCR and diesel oxidation catalyst in 2004. The system was 

designed to reduce NOx by 50 percent as well as PM by 25 percent. (Bradley, 2006)

The M/V Alice Austen has been operating with SCR since 2005. The vessel is in 

service during the night runs of the Staten Island Ferry system (9 p.m. to 5 a.m.). The 

route the vessel is assigned takes about an hour and includes two 20-minute runs and 

idling during passenger loading and unloading. There have been no problems with the 

SCR system.

(iii) San Francisco Bay Area Water Transit Authority (WTA) Ferry

The WTA is planning to build two new 149 passenger ferries to be put into service in 

late 2008 which will include exhaust aftertreatment to reduce NOx emissions by at least 

85 percent beyond Tier 2 standards. The ferries are being designed to incorporate a 

compact SCR system coupled with an oxidation catalyst with the 1410 hp Detroit Diesel 

propulsion engines. The inclusion of the aftertreatment system will require about six 

feet to be added to the vessel’s overall length. The system was derived from one that 

has been used on other mobile equipment. The ferries’ design includes a dry exhaust 

with a high exhaust stack. (WTA, 2006a)

(iv) Foss Tugboat with Hybrid System

The Foss Tug Company of Seattle, Washington recently “laid keel” on a Dolphin class 

hybrid tugboat. The tugboat will be a stern drive vessel used primarily for harbor assist 

services. The tugboat ’s electric drive units will be powered by two 670 horsepower 

battery packs coupled with two 335 horsepower diesel-fueled generators. Although the 

main engines will have lower horsepower than those found in the existing Dolphin class 

tugboat s, the total horsepower of the hybrid tugboat will be equal to that of the existing 

Dolphin class tugboat s – about 5,000 hp.

Foss anticipates a number of benefits from the use of hybrid technology. These 

benefits include over a 40 percent reduction in emissions of PM and NOx, lower fuel 

consumption, and a reduction in the noise associated with the operation of the vessel. 

It is anticipated that the vessel will begin operations in 2008. 
VI-11

(v) Humid Air Injection

SCX Ferries, Inc and MARAD tested the emission reduction potential of an air 

humidification system on a hydrofoil ferry in San Diego, California. The ferry is powered 

by four high-speed Detroit Diesel 12V92 diesel-fueled engines, each rated at 1050 hp 

driving two water jets. The water injection (fumigation) system reduces NOx by 

reducing peak combustion temperatures. The system was able to reduce NOx by about 

16 percent. (MARAD, 2003)

c. Combined Technologies

In 2006, Cleaire worked with Blue and Gold Ferries in San Francisco to install an 

aftertreatment control system on a ferry. The system installed consisted of a DPF and a 

lean NOx catalyst element. The lean NOx catalyst element was a diesel fuel injector 

located down-stream of the DPF. The diesel fuel served as a catalyst to reduce NOx.

The aftertreatment control system was sized and installed on the ferry based on a 

successful demonstration in on-road bus Detroit Diesel 4 stroke engines. The engines 

on the ferry were identical to those on the bus. During the course of emission testing 

the system on simulated ferry runs, the diesel fuel injector in the lean NOx catalyst 

element was thermally destroyed. After several attempts to resolve that issue, the 

demonstration and emission testing was discontinued. It is assumed that the failure 

was due to the difference in a ferries engine load and cycle when compared to that of 

an on-road bus. 

2. Future Emissions Testing Opportunities

The ARB staff has plans to test and quantify the emission reductions achieved with 

several of the demonstration projects over the next one to two years. These projects 

include the Foss hybrid tugboat and the WTA low emission ferry. In addition, the Red 

and White Ferry in San Francisco has requested assistance in determining the emission 

reductions they are achieving using a biodiesel blend diesel fuel in one of their new 

ferries. ARB is also co-funding the emission testing of a compact SCR unit in 

combination with a crankcase filter installed on an EMD 710 3,100 horsepower engine 

operating with a marine engine cycle. The EMD engine is commonly used in tugboats. 

The emission testing will be conducted at the Southwest Research Institute. 

F. Feasibility of Achieving Additional Emission Reductions From New-Build 

Ferry Propulsion Engines

The proposed regulation requires that all new-build ferries comply with an additional 

requirement for the ferry propulsion engines. In addition to having a propulsion engine 

that meets the current U.S. EPA marine engine emission standards, they must also 

install an after-treatment system that represents BACT at the time of acquisition to 

further reduce emissions of PM and NOx. The WTA requires that all new ferry 
VI-12

propulsion engines achieve 85 percent lower emissions than the current engine 

standard. The two ferries currently being built for WTA, discussed above, are 

guaranteed to meet this requirement using SCR combined with an oxidation catalyst. 

However, the failure of the SCR system on the Baylink Ferry illustrates the need to 

successfully demonstrate this technology on a California high speed ferry. 

While the Staten Island Ferry with SCR appears to be operating successfully, this is a 

larger slow speed vessel. There may be different design challenges for smaller 

catamaran type higher speed vessels such as the Baylink and WTA ferries. Staff chose 

not to prescribe specific emission reductions or technologies due to the lack of 

successful demonstrations. A BACT requirement is included in the proposed regulation 

to stimulate the development of emission control strategies for these vessels and allow 

additional reductions to be realized as technology develops. 
VI-13

REFERENCES:

(ARB, 2006) Joseph Calavita, California Air Resources Board. Personal 

communication. October 5-6, 2006.

(ARB, 2007) Kirk Rosenkranz, California Air Resources Board. Personnel 

communications with California boat builders and repair facilities. May 2007.

(Baylink, 2006) Martin Robbins, Baylink Ferry. Personal communication. October 24, 

2006. 

(Baylink, 2007) SCR Project-M/V Solano, June 30, 2007.

(DieselNet, 2003) DieselNet. http://dieselnet.com/tech/engine_adv.html

(FTA, 2007) Federal Transportation Administration. 

http://www.fta.dot.gov/grants_financing.html. August, 2007. 

(MARAD, 2003) U.S. Department of Transportation Maritime Administration Office of 

Shipbuilding and Marine Technology. Energy Technologies. Newsletter No. 04; Winter 

2003-2004. 

http://www.marad.dot.gov/nmrec/energy_technologies/images/ETNo4Winter0304.htm 

August 9, 2006.

 (WTA, 2006a) San Francisco Bay Area Water Transit Authority. “The SF Bay Area 

Water Transit Authority is Building Boats.” Press Release. May 9, 2006. 

http://www.watertransit.org/pressreleases/pressRelease050906.pdf

October 18, 2006.
VII-1

VII. ENVIRONMENTAL IMPACTS 

This chapter describes the potential environmental impacts of this proposed regulation. 

This proposed regulation is intended to protect the health of California’s citizens by 

reducing diesel engine emissions from harbor craft operating in California coastal and 

inland waters. An additional consideration is the impact that implementation of the 

proposed regulation may have on the environment. Based upon available information, 

the ARB staff has determined that no significant adverse environmental impacts should 

occur as the result of adopting the proposed regulation. This chapter describes the 

potential impacts that the proposed regulation may have on wastewater treatment, 

hazardous waste disposal, and air quality. 

A. Legal Requirements 

The California Environmental Quality Act (CEQA) and ARB policy require an analysis to 

determine the potential environmental impacts of proposed regulations. Because the 

ARB's program involving the adoption of regulations has been certified by the Secretary 

of Resources pursuant to Public Resources Code section 21080.5, the CEQA 

environmental analysis requirements may be included in the Initial Statement of 

Reasons (ISOR) for this rulemaking. In the ISOR, ARB must include a “functionally 

equivalent” document, rather than adhering to the format described in CEQA of an Initial 

Study, a Negative Declaration, and an Environmental Impact Report. In addition, staff 

will respond, in the Final Statement of Reasons for the regulation, to all significant 

environmental issues raised by the public during the public review period or at the 

Board public hearing.

Public Resources Code section 21159 requires that the environmental impact analysis 

conducted by ARB include the following:

• An analysis of reasonably foreseeable environmental impacts of the methods 

of compliance;

• An analysis of reasonably foreseeable feasible mitigation measures; and,

• An analysis of reasonably foreseeable alternative means of compliance with 

the regulation.

Compliance with the proposed regulation is expected to directly affect air quality and 

potentially affect other environmental media as well. Our analysis of the reasonable 

foreseeable environmental impacts of the methods of compliance is presented below. 

Regarding mitigation measures, CEQA requires an agency to identify and adopt 

feasible mitigation measures that would minimize any significant adverse environmental 

impacts described in the environmental analysis.

The proposed regulation is needed to reduce the risk from exposures to diesel PM as 

required by Health and Safety Code (HSC) section 39666 and 39667, to help fulfill the 

goals of the October 2000 Diesel Risk Reduction Plan (ARB, 2000), and to help meet 
VII-2

the goals of the Emission Reduction Plan for Ports and Goods Movement in California 

(ARB, 2006). The regulation is also necessary to fulfill ARB’s obligations under HSC 

43013 and 43018 to achieve the maximum feasible and cost effective emission 

reductions from all mobile source categories, including off-road diesel engines and 

equipment. The emission reductions from the proposed regulation in ambient levels of 

PM, NOx and reactive organic gases (ROG) will help make progress in meeting the 

State and Federal ambient air quality standards for ozone and PM in non-attainment 

areas of the State. Alternatives to the proposed regulation will be discussed in the 

Economic Impacts chapter of this report (Chapter VIII). ARB staff have concluded that 

there are no feasible alternative mitigation methods that would achieve similar diesel 

PM emission reductions at a lower cost. 

B. Effects on Air Quality

The proposed regulation will provide diesel PM and NOx emission reductions 

throughout California, especially in areas having ports, areas which in most cases are 

non-attainment for the State and federal ambient air quality standards for ozone, PM10, 

and PM2.5. The projected controlled emissions from harbor craft engines are 

presented in Table VII-1.

Table VII-1: Projected Annual Harbor Craft Emissions with

 Proposed Regulation Implementation

VI. 2004 

EMISSIO

NS

(tons/day)

2015 Emissions

(tons/day)

2020 Emissions

(tons/day) Category

PM NOx PM NOx PM NOx

Commercial Fishing 0.8 17.4 0.4 7.8 0.2 5.6

Charter Fishing 0.6 12.7 0.3 8.2 0.2 6.6

Ferries/Excursion 0.9 21.0 0.5 14.3 0.3 9.3

Tug 0.6 15.3 0.2 6.9 0.2 5.4

Tow 0.1 3.0 0.1 1.6 <0.1 1.4

Crew and Supply 0.1 1.4 <0.1 0.8 <0.1 0.7

Pilot <0.1 0.4 <0.1 0.2 <0.1 0.2

Work/Other 0.1 2.0 <0.1 1.2 <0.1 1.1

Total 3.3 73.2 1.6 41.2 1.0 30.9

Note: The numbers may not sum exactly due to rounding.

The reductions due specifically to the regulation are summarized in Table VII-2 and 

Table VII-3 below. As can be determined from the information provided in the tables, 

PM emissions will be 30 percent lower in 2015 and over 40 percent lower in 2020 than 

they would be without the regulation. The estimated NOx emissions are 23 percent 
VII-3

lower and 25 percent lower in 2015 and 2020, respectively due to the implementation of 

the proposed regulation. 

Table VII-2: Projected Statewide Diesel PM Benefits of the Proposed Regulation

Year

PM without 

Regulation 

(tons/day)

PM with 

Regulation 

(tons/day)

Emission 

Reductions from 

2004 (tons/day)

% Emission 

Reductions from 

2004

2004 3.3 3.3 0.0 0

2010 2.6 2.5 0.7 22

2015 2.3 1.6 1.6 50

2020 1.7 1.0 2.2 68

2025 1.2 0.9 2.4 74

Table VII-3: Projected Statewide NOx Benefits of the Proposed Regulation

Year

NOx without 

Regulation 

(tons/day)

NOx with 

Regulation 

(tons/day)

Emission 

Reductions from 

2004 (tons/day)

% Emission 

Reductions from 

2004

2004 73 73 0 0

2010 61 59 14 19

2015 54 41 32 44

2020 41 31 42 58

2025 32 28 45 62

When the combined benefits of the proposed regulation are considered in conjunction 

with existing programs, such as the ARB fuel regulations and U.S. EPA’s marine engine 

standards, the overall reductions in diesel PM and NOx emissions from harbor craft are 

significant. As shown in the tables above, diesel PM emissions from harbor craft will be 

reduced by 50 percent in 2015 and 74 percent in 2025 relative to what the emissions 

were in 2004. NOx emissions will be reduced 44 percent in 2015 and 62 percent in 

2025 relative to the 2004 baseline. 

Figure VII-1 and Figure VII-2 show the projected diesel PM and NOx emissions for 

California’s harbor craft fleet, both baseline emissions and with the impacts of the 

proposed regulation. We also anticipate reductions in reactive organic compounds and 

carbon monoxide; however, the emission reductions from these pollutants are not yet 

quantified in the emissions inventory. 
VII-4

Figure VII-1: Projected Diesel PM Emissions With and Without 

the Proposed Regulation

Commercial Harbor Craft Statewide PM Emissions

0

0.5

1

1.5

2

2.5

3

3.5

2004 2007 2010 2013 2016 2019 2022 2025

Calendar Year

Tons/day

Baseline Controlled with Proposed Regulation

Figure VII-2: Projected NOx Emissions With and Without

 the Proposed Regulation

Commercial Harbor Craft Statewide NOx Emissions

0

10

20

30

40

50

60

70

80

2004 2007 2010 2013 2016 2019 2022 2025

Calendar Year

Tons/day

Baseline Contolled with Proposed Regulation
VII-5

Between 2009 and 2022, we estimate approximately 2,400 tons of diesel PM and 

39,000 tons of NOx will be removed from California's air as a result of the regulation, as 

shown in Table VII-4. 

Table VII-4: Emission Benefits from Implementation of the Proposed Regulation

PM NOx

Emissions Reduced

 2009 to 2022 (tons) 2,400 38,950

Annual Average Reductions (tpy) 175 2,800

C. Health Benefits Analysis

1. Reduced Ambient Particulate Matter Levels

A substantial number of epidemiologic studies have found a strong association between 

exposure to ambient particulate matter (PM) and adverse health effects. (ARB, 2002) 

For this report, ARB staff evaluated the impacts the proposed regulation would have on 

potential cancer risks and conducted a quantitative analysis of seven potential noncancer health impacts associated with exposures to ambient levels of directly emitted 

diesel PM. 

a. Reduction in Potential Cancer Risks 

The reductions in diesel PM emissions that will result from implementation of the 

proposed regulation will reduce the public’s exposures to diesel PM emissions and the 

potential cancer risks associated with those exposures. The ARB staff used the air 

dispersion model and model inputs developed for the Port of Los Angeles (POLA) and 

Port of Long Beach (POLB) health risk assessment to estimate the reductions in 

potential cancer risk that would result from implementation of the proposed regulation in 

the area surrounding the two ports. Staff believes that the results from this analysis 

provide quantitative results for exposures around the POLA and POLB and are 

generally applicable to other ports in California, providing a qualitative estimate for 

those areas. 

To investigate the reductions in potential risks that will result as emissions from harbor 

craft are reduced, ARB staff used dispersion modeling and the projected 2015 and 2020 

emissions inventories to estimate the above ambient concentration of diesel PM 

emissions that result from the operation of harbor craft at the POLA and POLB in 2015 

and 2020. The potential cancer risks from exposures to the projected 2015 and 2020 

emissions were then estimated and compared to the 2002 levels to determine how the 

potential risks will change. As shown in Figures VII-3 and VII-4, we expect a significant 

decline in the number of people exposed to elevated risk levels from harbor craft 

emissions and the acres impacted as the proposed regulation is implemented. Based 

on our analysis, we estimate that in 2015 there will be a 50 percent reduction in the 
VII-6

number of residential acres and population exposed to diesel PM concentrations greater 

than 10 per million, and a 65 percent reduction in 2020. 

Figure VII-3: Residential Areas Impacted by the Proposed Regulation for Baseline

Year (2004) and Projections for 2015 and 2020 at the POLA/LB

Figure VII-4: Population Affected by the Proposed Regulation for Baseline

Year (2004) and Projections for 2015 and 2020 at the POLA/LB

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

Residential Area (Acres)

2004 Baseline

2015 with Reg

2020 with Reg

2004 Baseline 140,790 1,977 89 0

2015 with Reg 69,703 69 0 0

2020 with Reg 47,869 0 0 0

Risk > 10 Risk > 100 Risk > 200 Risk > 500

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

2,000,000

Number of Persons

2004 Baseline

2015 with Reg

2020 with Reg

2004 Baseline 1,722,364 44,155 7,651 0

2015 with Reg 943,280 6,267 0 0

2020 with Reg 629,594 0 0 0

Risk > 10 Risk > 100 Risk > 200 Risk > 500
VII-7

b. Non-Cancer Health Impacts and Valuations

To determine the impacts from the proposed regulation on non-cancer health endpoints, 

ARB staff used the methodology described previously in Chapter III to evaluate the 

change in ambient PM levels that are expected due to implementation of the proposed 

regulation. This analysis shows that the statewide cumulative impacts of the emissions 

reduced through this regulation from year 2009 through 2025 are approximately:

• 310 premature deaths (90 to 530, 95% confidence interval (CI))

• 70 hospital admissions due to respiratory causes (40 to 90, 95% CI) 

• 120 hospital admissions due to cardiovascular causes (80 to 190, 95% CI)

• 8,100 cases of asthma-related and other lower respiratory symptoms (3,100 to 

13,000, 95% CI)

• 670 cases of acute bronchitis (0 to 1,500, 95% CI)

• 53,000 work loss days (45,000 to 61,000, 95% CI)

• 300,000 minor restricted activity days (250,000 to 360,000, 95% CI)

Table VII-5 lists the impacts associated with primary and secondary diesel emissions 

separately. The methodology for estimating these health impacts is outlined below and 

details can be found in Appendix A of the Emission Reduction Plan for Ports and Goods 

Movement in California (ARB, 2006) 9.

 

9

http://www.arb.ca.gov/planning/gmerp/march21plan/appendix_a.pdf
VII-8

Table VII-5: Total Health Benefits Associated with Reductions in Emissions

from Commercial Harbor Craft (2009-2025)A

Endpoint Pollutant

# of Cases

95% C.I.

(Low)

# of Cases

(Mean)

# of Cases

95% C.I.

(High)

PM 50 200 340

Premature Death NOx 30 110 190

Total 90 310 530

PM 30 40 60

NOx 20 20 30

Hospital 

admissions 

(Respiratory) Total 40 70 90

PM 50 80 120

NOx 30 40 70

Hospital 

admissions 

(Cardiovascular) Total 80 120 190

PM 1,900 5,000 8,100

NOx 1,200 3,100 4,900

Asthma & Lower 

Respiratory 

Symptoms Total 3,100 8,100 13,000

PM 0 420 920

Acute Bronchitis NOx 0 250 540

Total 0 670 1,500

PM 28,000 34,000 39,000

Work Loss Days NOx 16,000 19,000 22,000

Total 45,000 53,000 61,000

PM 160,000 190,000 230,000

NOx 91,000 110,000 130,000 Minor Restricted 

Activity Days

Total 250,000 300,000 360,000

A Health effects from primary and secondary PM are labeled PM and NOx, respectively. The sum of 

PM and NOx impacts may not equal the total given due to rounding.

c. Economic Valuation of Non-Cancer Health Effects 

The U.S. EPA has established $4.8 million in 1990 dollars at the 1990 income level as 

the mean value of avoiding one premature death. (EPA, 1999) This value is the mean 

estimate from five contingent valuation studies and 21 wage-risk studies. Contingent 

valuation and wage-risk studies examine the willingness to pay (or accept) for a minor 

decrease (or increase) in risk of premature death. For example, if 10,000 people are 

willing to pay $800 apiece for risk reduction of 1/10,000 then collectively the willingnessto-pay for avoiding a premature death, in this example, would be $8 million. This is also 

known as the “value of a statistical life” or VSL.10

 

10 U.S. EPA’s most recent regulatory impact analyses, (U.S. EPA 2004, 2005), apply a different VSL 

estimate ($5.5 million in 1999 dollars, with a 95 percent confidence interval between $1 million and 

$10 million). This revised value is based on more recent meta-analytical literature, and has not been 

endorsed by the Environmental Economics Advisory Committee (EEAC) of U.S. EPA’s Science Advisory 

Board (SAB). Until U.S. EPA’s SAB endorses a revised estimate, CARB staff continues to use the last 

VSL estimate endorsed by the SAB, i.e., $4.8 million in 1990 dollars. 
VII-9

As real income increases, people are willing to pay more to prevent premature death. 

U.S. EPA adjusts the 1990 value of avoiding a premature death by a factor of 1.20111 to 

account for real income growth from 1990 through 2020. (EPA, 2004) Assuming that 

real income grows at a constant rate from 1990 until 2020, we adjusted VSL for real 

income growth, increasing it at a rate of approximately 0.6 percent per year. We also 

updated the value to 2006 dollars. After these adjustments, the value of avoiding one 

premature death is $8.2 million in 2006, $8.6 million in 2015 and $9.2 million in 2025, all 

expressed in 2006 dollars.

The U.S. EPA also uses the willingness-to-pay (WTP) methodology for some non-fatal 

health endpoints, including lower respiratory symptoms, acute bronchitis and minor

restricted activity days. WTP values for these minor illnesses are also adjusted for 

anticipated income growth through 2025, although at a lower rate (about 0.2 percent per 

year in lieu of 0.6 percent per year).

For work-loss days, the U.S. EPA uses an estimate of the parent’s lost wages, (EPA, 

2004), which ARB adjusts for projected real income growth, at a rate of approximately 

1.5 percent per year.

“The Economic Value of Respiratory and Cardiovascular Hospitalizations,” (ARB, 2003), 

calculated the cost of both respiratory and cardiovascular hospital admissions in 

California as the cost of illness (COI) plus associated costs such as loss of time for 

work, recreation and household production. When adjusting these COI values for 

inflation, ARB uses the Consumer Price Index (CPI) for medical care rather than the 

CPI for all items.

Table VII-6 lists the valuation of avoiding various health effects, compiled from ARB and 

U.S. EPA publications, updated to 2006 dollars. The valuations based on WTP, as well 

as those based on wages, are adjusted for anticipated growth in real income.

 

11 U.S. EPA’s real income growth adjustment factor for premature death incorporates an elasticity 

estimate of 0.4.
VII-10

Table VII-6: Undiscounted Unit Values for Health Effects

 (at various income levels in 2006 dollars) A

Health Endpoint 2006 2015 2025 References

Mortality

Premature death ($ million) 8.2 8.6 9.2 U.S. EPA (1999, p. 70-72, 

2000, (2004, p. 9-121)

Hospital Admissions

Cardiovascular ($ thousands) 43 48 54 ARB (2003), p. 63

Respiratory ($ thousands) 35 39 44 ARB (2003), p. 63

Minor Illnesses

Acute Bronchitis 451 459 469 U.S. EPA (2004), 9-158

Lower Respiratory Symptoms 20 20 21 U.S. EPA (2004), 9-158

Work loss day 189 217 252 2002 California wage data, 

U.S. Department of Labor

Minor restricted activity day (MRAD) 64 65 66 U.S. EPA (2004), 9-159

A

The value for premature death is adjusted for projected real income growth, net of 0.4 elasticity. 

Wage-based values (Work Loss Days) are adjusted for projected real income growth, as are WTPderived values (Lower Respiratory Symptoms, Acute Bronchitis, and MRADs). Health endpoint

values based on cost-of-illness (Cardiovascular and Respiratory Hospitalizations) are adjusted for 

the amount by which projected CPI for Medical Care (hospitalization) exceeds all-item CPI.

Benefits from the proposed Commercial Harbor Craft Rule are substantial. The ARB 

staff estimates the benefits to be nearly $2.0 billion using a 3 percent discount rate or 

$1.3 billion using a 7 percent discount rate. (ARB follows U.S. EPA practice in reporting 

results using both 3 percent and 7 percent discount rates.) Nearly all of the monetized 

benefits result from avoiding premature death. The estimated benefits from avoided 

morbidity are less than $30 million with a 3 percent discount rate and less than $20 

million with a 7 percent discount rate. Approximately three-fifths of the benefits are 

associated with reduced diesel PM, and the remaining two-fifths with reduced NOx.

2. Reduced Ambient Ozone Levels

Emissions of NOx and ROG are precursors to the formation of ozone in the lower 

atmosphere. Exhaust from diesel engines contributes a substantial fraction of ozone 

precursors in any metropolitan area. Therefore, reductions in NOx and ROG from 

diesel engines would make a considerable contribution to reducing exposures to 

ambient ozone. Controlling emissions of ozone precursors would reduce the 

prevalence of the types of respiratory problems associated with ozone exposure and 

would reduce hospital admissions and emergency visits for respiratory problems. 
VII-11

D. Reasonably Foreseeable Environmental Impacts as a Result of Potential 

Compliance Methods

The primary compliance strategy proposed in the regulation is accelerated engine 

replacement. The ARB staff anticipates that the majority of harbor craft 

owner/operators will choose to comply with the requirements of the proposed regulation 

using the repower strategy. Staff does not foresee any negative environmental impacts 

associated with the use of engine repowers as a primary strategy. 

One compliance option with potential adverse environmental impacts is the use of 

diesel emission control strategies. To date, there are no ARB verified after-treatment 

controls for marine engines. As such, ARB is allowing the use of non-verified aftertreatment control devices in the hope of achieving some reductions of diesel PM 

associated with harbor craft due to the installation of after-treatment controls. The ARB 

staff does not anticipate significant reductions of diesel PM from harbor craft attributable 

to after-treatment controls until such time as those technologies are proven to be 

effective and durable when used in the marine environment. The ARB continues to 

support projects that utilize after-treatment controls in the hope that those technologies 

will become verified in the future.

The ARB has identified potential adverse environmental impacts from the use of diesel 

oxidation catalysts (DOCs) and diesel particulate filters (DPFs). These include a 

potential increase in sulfate PM, a potential increase in nitrogen dioxide (NO2) from 

some DPFs, and the potential for creating hazardous wastes. As described below, 

options are available to mitigate these potential adverse impacts.

1. Diesel Oxidation Catalyst (DOC)

Two potential adverse environmental impacts of the use of DOCs have been identified. 

First, as is the case with most processes that incorporate catalytic oxidation, the 

formation of sulfates increases at higher temperatures. Depending on the exhaust 

temperature and sulfur content of the fuel, the increase in sulfate particles may offset 

the reductions in soluble organic fraction emissions. With the ARB requiring the use of 

ultra low sulfur diesel fuel (<15 ppm sulfur), this effect has been minimized, but still 

needs to be taken into account when considering whether or not to use a DOC as a 

preferred emission reduction strategy.

Second, a DOC could be considered a “hazardous waste” at the end of its useful life 

depending on the materials used in the catalytic coating. Because catalytic converters 

have been used on gasoline powered on-road vehicles for many years, there is a very 

well-established market for these items (see, for example, http://pacific.recycle.net – an 

Internet posting of buyers and sellers of various scrap materials). In the recycling 

process, the converters are broken down, and the metal is added to the scrap-metal 

stream for recycling, while the catalysts (one or a combination of the platinum group 

metals) are extracted and reused. 
VII-12

Because of platinum’s high activity as an oxidation catalys t, it is the predominant 

platinum group metal used in the production of DOCs. There is a very active market for 

reclaimed platinum for use in new catalytic converters, jewelry, fuel cells, cathode ray 

tube screens, catalysts used during petroleum refining operations, dental alloys, oxygen 

sensors, platinum electrode spark plugs, medical equipment, and platinum-based drugs 

for cancer treatment, to name a few. (Kendall, 2002) (Kendall, 2003)

2. Catalyzed Diesel Particulate Filters

These devices are composed of a ceramic diesel particulate filter along with a platinum 

catalyst to catalyze the oxidation of carbon-containing emissions and significantly 

reduce diesel PM emissions. This is an obvious positive environmental impact. 

However, there are also inorganic solid particles present in diesel exhaust, which are 

captured by diesel particulate filters. These inorganic materials are metals derived from 

engine oil, diesel fuel, or engine wear and tear. While the PM filter is capable of 

capturing inorganic materials, these materials are not oxidized into a gaseous form and 

expelled. 

Because these materials would otherwise be released into the air, the filters are 

benefiting the environment by capturing these metallic particles, known as “ash.” 

However, the ash that is collected in the PM filter must be removed from the filter 

periodically to maintain the filter’s effectiveness.

Ash collected from a diesel engine using a typical lubrication oil and no fuel additives 

has been analyzed and is primarily composed of oxides of the following elements: 

calcium, zinc, phosphorus, silicon, sulfur, and iron. Zinc is the element of primary 

concern because, if present in high enough concentration, it can be considered a 

hazardous waste. Title 22, CCR, section 66261.24 establishes two limits for zinc in a 

waste: 250 milligrams per liter for the Soluble Threshold Limit Concentration and 

5,000 milligrams per kilogram for the Total Threshold Limit Concentration. The 

presence of zinc at or above these levels would cause a sample of ash to be 

characterized as a hazardous waste. 

Under California law, it is the generator's responsibility to determine whether their waste 

is hazardous or not. Applicable hazardous waste laws are found in the HSC, 

division 20; title 22, CCR, division 4.5; and title 40 of the Code of Federal Regulations. 

Staff recommends owners that install a diesel particulate filter on an engine to contact 

both the manufacturer of the diesel emission control system and the California 

Department of Toxic Substances Control (DTSC) for advice on proper waste 

management. 

The ARB staff has consulted with personnel of the DTSC regarding management of the 

ash from diesel particulate filters. The DTSC personnel have advised ARB that it has a 

list of facilities that accept waste from businesses that qualify as a conditionally exempt 

small quantity generator. Such a business can dispose of a specific quantify of 
VII-13

hazardous waste at certain Household Hazardous Waste events, usually for a small fee. 

An owner who does not know whether or not he qualifies or who needs specific 

information regarding the identification and acceptable disposal methods for this waste 

should contact the California DTSC.12

Additionally, the technology exists to reclaim zinc from waste. For example, the 

Swedish company MEAB has developed processes for extracting zinc and cadmium 

from various effluents and industrial waste streams. Whether reclamation for reuse will 

be economically beneficial remains to be seen. (MEAB, 2003)

Because of the time and costs associated with filter maintenance, there are also efforts 

by industry to reduce the amount of ash formed. Most of the ash is formed from the 

inorganic materials in engine oil, particularly from zinc-containing additives necessary to 

control acidification of engine oil – due in part to sulfuric acid derived from sulfur in 

diesel fuel. As the sulfur content of diesel fuel is decreased, the need for acid 

neutralizing additives in engine oil should also decrease. A number of technical 

programs are ongoing to determine the impact of changes in oil ash content and other 

characteristics of engine oil on exhaust emission control technologies and engine wear 

and performance. 

It may also be possible to reduce the ash level in diesel exhaust by reducing oil 

consumption from diesel engines. Diesel engine manufacturers over the years have 

reduced engine oil consumption in order to reduce PM emissions and to reduce 

operating costs for engine owners. Further improvements in oil consumption may be

possible in order to reduce ash accumulation rates in diesel particulate filters.

In addition, measurements of NOx emissions for heavy-duty diesel vehicles equipped 

with passive catalyzed filters have shown an increase in the NO2 portion of total NOx 

emissions, although the total NOx emissions remain approximately the same. In some 

applications, passive catalyzed filters can promote the conversion of nitrogen oxide 

(NO) emissions to NO2 during filter regeneration. More NO2 is created than is actually 

being used in the regeneration process; and the excess is emitted. The NO2 to NOx 

ratios could range from 20 to 70 percent, depending on factors such as the diesel 

particulate filter systems, the sulfur level in the diesel fuel, and the duty cycle. 

(DaMassa, 2002) 

Formation of NO2 is a concern because it irritates the lungs and lowers resistance to 

respiratory infections. Individuals with respiratory problems, such as asthma, are more 

susceptible to the effects. In young children, nitrogen dioxide may also impair lung 

development. In addition, a higher NO2/NOx ratio in the exhaust could potentially result 

in higher initial NO2 concentrations in the atmosphere which, in turn, could result in 

higher ozone concentrations. 

 

12 Information can be obtained from local duty officers and from the DTSC web site at 

http://www.dtsc.ca.gov.
VII-14

Model simulations have shown that a NO2 to NOx emission ratio of approximately 

20 percent would nearly eliminate any impact of increased NO2 emissions. 

(DaMassa, 2002). According to the model, at the NO2 to NOx ratio of 20 percent, there 

will be a decrease of the 24-hour ozone exposure (greater than 90 parts per billion) by 

two percent while an increase of the peak 1-hour NO2 by six percent (which is still 

within the NO2 standard). 

The health benefits derived from the use of PM filters are immediate and offset the 

possible adverse effects of increases in NO2 emissions. For this reason, a cap of 

20 percent NO2 to NOx emission ratio was established for all diesel emission control 

systems through ARB’s Verification Procedure.

3. Alternative Fuels

As discussed in Appendix E, a number of alternative fuels and alternative diesel fuels 

show great promise in their potential to reduce diesel PM emissions. These include 

alternative diesel fuels such as biodiesel, emulsified diesel fuel, and Fischer-Tropsch 

fuels, and alternative fuels such as natural gas. No significant negative environmental 

impacts have been determined from the use of alternative fuels. With respect to 

alternative diesel fuels, there may be a slight increase in NOx emissions as a result of 

biodiesel use. (Hofman and Solseng, 2002)

To ensure that there are no adverse impacts from the use of alternative diesel fuels, the 

proposed regulation requires any alternative diesel-fuel or fuel additives used in a 

harbor craft engine meet the following requirements:

a) be CARB diesel fuel; or

b) an “alternative diesel fuel” as defined in subsection (d)(2) of the proposed 

regulatory language; or

c) any alternative diesel fuel that does not meet subsection (d)(2) of the 

proposed regulatory language, but is certified by ARB as meeting the 

requirements of the Verification Procedure; or

d) CARB diesel fuel used with fuel additives that meets the requirements of 

the Verification Procedure; or

e) any combination of alternative fuels described above. 

The Verification Procedure permits verification only if a multimedia evaluation of the use 

of the alternative diesel fuel or additive has been conducted. In addition, verification 

requires a determination by the California Environmental Policy Council that such use 

will not cause a significant adverse impact on public health or the environment pursuant 

to HSC section 43830.8 (see Public Resource Code, section 71017). 
VII-15

E. Reasonably Foreseeable Mitigation Measures

The ARB staff has concluded that no significant adverse environmental impacts should 

occur from adoption of and compliance with the proposed regulation. Therefore, no 

mitigation measures would be necessary.

F. Reasonably Foreseeable Alternative Means of Compliance with the 

Proposed Regulation

Alternative means to comply with the proposed regulation are provided through the 

availability to submit Alternative Compliance Plans, the use of diesel emission control 

strategies to achieve the same emission reductions that would be achieved through 

engine replacement, demonstrating that the engine in question already meets the most 

current U.S. EPA marine engine emission standards, or if the vessel owner/operator 

has rebuilt the engine to meet the most current U.S. EPA marine engine emission 

standards.

Although there are issues associated with the use of alternative diesel emission control 

strategies to achieve reductions of emissions of NOx and diesel PM from harbor craft, 

ARB staff believes that there are ways to address and mitigate any adverse 

environmental impacts associated with a specific emission control strategy. 

Two of the alternative compliance strategies described above, use of aftertreatment 

diesel emission control strategies and engine rebuilds, provide limited benefits 

associated with the reduction of NOx and diesel PM from harbor craft and delay final 

compliance with the proposed regulation. These compliance options are needed

because they provide the regulated community with some flexibility for compliance with 

the proposed regulation. These options also promote the development of cleaner 

retrofit and rebuild technologies for harbor craft.

G. Impact on Global Warming

Global warming is the process whereby emissions from anthropogenic sources, 

together with naturally-occurring gases, absorb infrared radiation in the atmosphere, 

leading to an increase in ambient temperatures world-wide. Compounds that potentially 

contribute to global warming include six substances identified in the Kyoto Protocol. 

These substances are: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), 

hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride (SF6). These substances 

are all gases that have long lifetimes in the atmosphere, anywhere from a year to 

several thousand years depending on the gas.

Climate research has identified other chemical species that also have potential to alter 

the Earth’s climate. These other chemical species, which have much shorter 

atmospheric lifetimes than CO2 (several days, or less, depending on the chemical 

species), have not been directly included in climate change-related emission reduction 
VII-16

efforts due to the scientific uncertainty of their magnitude of potential climate changing 

impacts.

The chemical species not cited in the Kyoto Protocol are primarily anthropogenic 

pollutants emitted principally as by-products of fossil fuel and biomass combustion. 

One of the confounding aspects associated with these non-Kyoto chemical species is 

the scientific community’s uncertainty as to whether some of these chemical species 

have a warming or cooling effect on the world-wide climate. The chemical species 

thought to result in net warming include carbon monoxide (CO), volatile organic 

compounds, hydrogen (H2), and the black carbon fraction of particulate matter (PM). 

With the exception of PM, the potential net warming effect of these chemical species is 

the result of the formation of tropospheric ozone (O3) and methane. Two non-Kyoto 

chemical species that may have a net cooling effect are NOx and sulfur dioxide (SO2).

Typically, Global Warming Potential (GWP) the metric used to compare the relative 

significance of pollutants with respect to their impacts on global warming. The GWP of 

a specific substance is a measure of the additional amount of heat trapped in the 

atmosphere when one kilogram of that substance is instantaneously released to the 

atmosphere, relative to the instantaneous release of one kilogram of CO2. A GWP is 

calculated using computer models that incorporate the radiative heat balance of the 

atmosphere and the chemical kinetics of all the substances involved. The atmosphere 

is assumed to be in a steady-state when the GWP of a substance is modeled. Changes 

in atmospheric temperature are modeled based on the introduction of a kilogram of a 

potential global warming substance.

The primary strategy employed by the proposed harbor craft regulation focuses on the 

replacement of older, dirtier, unregulated and Tier 1 engines with cleaner Tier 2 

engines. Many of the engines being replaced are 2-stroke engines with mechanical 

controls. These engines will be replaced with electronically controlled 4-stroke engines. 

These electronically controlled 4-stroke engines are smaller, lighter, less polluting, and 

should reduce green house gases compared to the older, in-use engines, including a 

reduction in emissions of black carbon (a component of diesel PM and a likely

contributor to global warming). 

Conversely, the additional emission control requirement for new-build ferries may result 

in slightly increased carbon dioxide (CO2) for some applications. This may occur, for 

example, if vessel operators choose to comply with the regulations by using exhaust 

treatment technologies that use vessel power (e.g., scrubbers, selective catalytic 

reduction), increase the weight of the vessel, increase the engine back pressure, or 

require a larger engine to be installed on the vessel. 

Taking into account both the green house gas reductions of the newer engines and the 

increases associated with new-build ferries, the overall impact of the regulation on 

global warming is expected to be negligible. 

 
VII-17

REFERENCES:

(ARB, 2000) Air Resources Board. Risk Reduction Plan to

Reduce Particulate Matter Emissions from Diesel-Fueled Engines and Vehicles.

http://www.arb.ca.gov/diesel/documents/rrpapp.htm; October 2000.

(ARB, 2002) Air Resources Board and Office of Environmental Health Hazard 

Assessment. Public Hearing to Consider Amendments to the Ambient Air Quality 

Standards for Particulate Matter and Sulfates, Staff Report.

http://www.arb.ca.gov/research/aaqs/std-rs/pm-final/pm-final.htm; May 2002.

(ARB, 2003) Air Resources Board. May 2003. Final Research Report: The Economic 

Value of Respiratory and Cardiovascular Hospitalizations.

ftp://ftp.arb.ca.gov/carbis/research/apr/past/99-329.pdf

(ARB, 2006) California Air Resources Board. Emission Reduction Plan for Ports and 

Goods Movement in California; April 2004.

 (DaMassa, 2002) DaMassa, John. California Air Resources Board. Presentation: Air 

Quality Effects of Trap-Related Emissions (Updated); February 6, 2002.

 

(Kendall, 2002) Kendall, Tom; Johnson Matthey. Platinum 2002; 

http://www.platinum.matthey.com/publications/1051543656.html; May 2002. 

(Kendall, 2003) Kendall, Tom; Johnson Matthey. Platinum 2003; 

http://www.platinum.matthey.com/publications/1059138410.html; May 2003. 

(MEAB, 2003) Metallextraktion AB (MEAB). http://www.meab-mx.se/en/index.htm; 

August 2003. 

(Krewski et al., 2000) Krewski D.; Burnett R.; Goldberg M.; Hoover K.; Stemiatychi

J.; Jerrett M.; Abrahamovicz M.; White W. Health Effects Institute, Cambridge, 

Massachusetts. Reanalysis of the Harvard Six Cities Study and the American Cancer 

Society Study of Particulate Air Pollution and Mortality. 

http://es.epa.gov/ncer/science/pm/hei/Rean-ExecSumm.pdf; 2000.

(Lloyd and Cackette, 2001) Lloyd, A.C.; Cackette, T.A.; J Air Waste Management 

Assoc. Diesel Engines: Environmental Impact and Control;., 51:809-847. 

http://www.arb.ca.gov/research/seminars/lloyd/AWMA2001/JAWMADieselCriticalRevie

w.pdf; 2001.

(EPA, 1999) United States Environmental Protection Agency. The Benefits and Costs 

of the Clean Air Act 1990 to 2010. EPA-410-R-99-001. 

http://www.epa.gov/air/sect812/copy99.html; November 1999.
VII-18

(EPA, 2000) United States Environmental Protection Agency., Guidelines for Preparing 

Economic Analyses. EPA240-R-00-003. http://www.epa.gov/opei/pubsinfo.htm; 

September 2000.

(EPA, 2003) United States Environmental Protection Agency, Assessment and 

Standards Division, Office of Transportation and Air Quality. Draft Regulatory Impact

Analysis: Control of Emissions of Air Pollution from Nonroad Diesel Engines and Fuel. 

EPA420-R-03-008. CD-ROM. Research Triangle Park, North Carolina. 

http://www.epa.gov/otaq/cleaner-nonroad/r03008.pdf; April 2003.

(EPA, 2004) United States Environmental Protection Agency. May, 2004. Final 

Regulatory Impact Analysis: Control of Emissions from Nonroad Diesel Engines. EPA420-R-04-007. Office of Transportation and Air Quality.

http://www.epa.gov/otaq/regs/nonroad/equip-hd/2004fr.htm#ria
VIII-1

VIII. ECONOMIC IMPACTS

In this chapter, the estimated costs and economic impacts associated with 

implementation of the proposed regulation for commercial harbor craft are presented. 

The expected capital and recurring costs for potential compliance options, the cost and 

associated economic impacts on businesses, as well as an analysis of the costeffectiveness of the proposed regulation are presented. 

A. Summary of the Economic Impacts

In assessing the costs associated with the proposed regulation, ARB staff developed 

two different estimates, one for “regulatory costs” and another for “new equipment 

costs.” Regulatory costs are the estimated costs resulting from the proposed 

regulations taking into consideration the residual value of the in-use engine being 

replaced, the residual value of the most recent engine rebuild work, aftertreatment costs 

for new ferries, recordkeeping and reporting costs, and the time value of money 

associated with the early engine replacement. New equipment costs are the estimated 

total out-of-pocket costs for purchasing and installing a new engine (engine replacement 

cost) in ferries, excursion vessels, tugboat s, and towboats; new ferry aftertreatment 

costs; and recordkeeping and reporting costs.

Staff estimates the lifetime regulatory cost for complying with the proposed regulation to 

be approximately $140 million (2006 dollars). This corresponds to about $10 million 

annually from 2009 through 2022. New equipment costs are estimated at 

approximately $460 million dollars (2006 dollars) over the lifetime of the proposed 

regulation (2009 to 2022). The portion of new equipment costs for purchasing and 

installing a new engine are costs that the vessel owner would eventually pay, but the 

proposed regulation requires this service to be performed earlier than normal. 

Staff evaluated the economic impacts of the proposed regulation by estimating the 

effect of the regulatory cost on the “return on owner’s equity” (ROE) for a typical 

business. 

Using the ROE approach, we found that the overall change in ROE would range from a

negligible decline of about 0.5 percent for a typical tow company, to a slightly more

significant decline of 3.5 percent for a ferry/excursion vessel or tug company assuming 

affected businesses absorb the entire regulation costs. Staff’s analysis indicates that 

the change in ROE could be larger for small businesses. However, in most cases, ferry, 

tug, and tow businesses provide a needed service that is not easily replaced and they 

will likely be able to raise their fees to pay for the temporary increase in costs. 

Additionally, businesses with compliance dates at least three years in the future may be 

eligible for incentive grant funds if they choose to comply early. Overall, most affected 

businesses will be able to absorb the costs of the proposed regulation with no 

significant adverse impacts on their profitability. 
VIII-2

Multiple federal, State, and local agencies will be impacted by the proposed regulation. 

The majority of the agencies not be affected by the in-use compliance requirements and 

will only be subject to the reporting requirement, resulting in costs of approximately 

$100 per engine. One State agency, the California Department of Transportation 

(Caltrans) and three local agencies which operate passenger ferries would be impacted 

by the in-use engine requirements. Regulatory costs to these agencies range from 

about $2,000 to $2 million. There would be significant costs to the ARB to implement 

and enforce the regulation. Staff estimates that ARB’s cost to implement the reporting 

program (initial report) would be approximately $25 to $50 per engine. An additional 

annual cost of $10 to $100 per engine (after the first year) is estimated to cover an 

inspection and report update at the time of final compliance with the regulation. It was 

assumed that each engine would be inspected once. These total costs are estimated to 

be $200,000 to $600,000 for the regulation. The ARB’s administrative costs for 

outreach, educational efforts, and technical assistance would be absorbed within 

existing budgets and resources. 

Cost-effectiveness is expressed in terms of costs in dollars per unit of emissions 

reduced (pounds or tons). The cost-effectiveness for the proposed regulation is 

determined by dividing the regulatory costs by the total pounds of diesel PM reduced 

during the years 2009 to 2022. All costs are in 2006 equivalent expenditure dollars. 

Table VIII-1 shows the cost-effectiveness estimate for the proposed regulation 

expressed three ways. The cost-effectiveness values are well within the range of cost 

effectiveness for other diesel engine regulations adopted by the Board.

Table VIII-1: Summary of Average Cost Effectiveness for the Period 2009-2022

Emissions Total Regulatory Cost

2009 – 2022

Total Emissions Reduced

2009 - 2022

Total CostEffectiveness

All costs assigned to PM

PM $140,000,000 4,900,000 lbs $29/lb

Divide Costs Equally Between PM and NOx

PM $70,000,000 4,900,000 lbs $14.50/lb

NOx $70,000,000 39,000 tons $1,800/ton

Combine PM and NOx Emissions

PM + NOx $140,000,000 83,000,000 lbs $1.70/lb

All values rounded

The estimated value of the health benefits associated with the proposed regulation is 

substantial. Staff estimates the statewide benefits to be nearly $2.0 billion using a 

3 percent discount rate or $1.3 billion using a 7 percent discount rate. (ARB follows 

U.S. EPA practice in reporting results using both 3 percent and 7 percent discount 

rates.) Nearly all of the monetized benefits result from avoiding premature death. 
VIII-3

B. Legal Requirements

In this section, the legal requirements that must be satisfied in analyzing the economic 

impacts of the regulation are explained.

Section 11346.3 of the Government Code requires State agencies to assess the 

potential for adverse economic impacts on California business enterprises and 

individuals when proposing to adopt or amend any administrative regulation. The 

assessment shall include a consideration of the impact of the proposed regulation on 

California jobs, business expansion, elimination or creation, and the ability of California 

business to compete with businesses in other states. Also, State agencies are required 

to estimate the cost or savings to any State or local agency in accordance with 

instructions adopted by the Department of Finance (DOF). The estimate shall include 

any non-discretionary cost or savings to local agencies and the cost or savings in 

federal funding to the State.

In addition, Health and Safety Code section 57005 requires the ARB to perform an 

economic impact analysis of submitted alternatives to a proposed regulation before 

adopting any major regulation. A major regulation is defined as a regulation that will 

have a potential cost to California business enterprises in an amount exceeding ten 

million dollars. Because the estimated cost of the regulation does exceed 10 million 

dollars, an economic analysis of submitted alternatives to the proposal was conducted.

The following is a description of the methodology used to estimate costs as well as ARB 

staff’s analysis of the economic impacts on California businesses and State and local 

agencies.

C. Methodology for Estimating Costs Associated with Proposed Regulation

In this section, the estimated costs associated with the proposed regulation are 

discussed.

Briefly, the methodology entailed:

• Two different estimates of costs were developed, regulatory costs and new 

equipment costs. 

- The regulatory costs are the estimated costs resulting from the proposed 

regulations taking into consideration the residual value of the in-use 

engine being replaced, the residual value of the most recent engine 

rebuild work, aftertreatment costs for new ferries, recordkeeping and 

reporting costs, and the time value of money associated with the early 

engine replacement. 

- New equipment costs are the estimated total out-of-pocket costs for 

purchasing and installing a new engine (engine replacement cost), new 

ferry aftertreatment costs, and recordkeeping and reporting costs. The 

portion of new equipment out-of-pocket costs for purchasing and installing 

a new engine are costs that the vessel owner would eventually pay, but 
VIII-4

the proposed regulation requires this service to be performed earlier than 

normal. 

• Engine replacement (repowering) was the assumed in-use engine compliance 

option. 

• Operating and maintenance costs for replacement engines were assumed to be 

the same as for an existing engine and were not included.

• The 2004 emissions inventory was projected to future years to determine the 

number of pre-2008 engines remaining that would need to be replaced each year 

and the number of new vessels added to the fleet each year.

• Aftertreatment costs for new ferries include equipment costs and estimated 

maintenance costs for PM controls.

• Reporting costs were estimated at about $100 per engine per report.

• Costs were estimated in 2006 dollars.

Based on the ARB Survey and updated emissions inventory, there are an estimated

300 private ferry, excursion vessel, tugboat , and towboat companies operating about 

670 harbor craft with over 1,900 diesel engines that will have to meet new engine 

standards. The regulatory and new equipment costs will vary depending on the number 

of harbor craft a company operates and the option chosen to comply with the proposed 

regulation. Vessel categories other than ferry, excursion vessel, tugboat , and towboat,

will incur only minor costs associated with monitoring (hour meter), recordkeeping, and 

reporting requirements.

1. Costs

a. Engine Replacement (Repower) Costs: 

The estimated costs for purchasing and installing a new diesel-fueled engine in an inuse harbor craft were determined using actual cost data from the Moyer Program 

submittals and cost information provided by the San Francisco Bay Area Water Transit 

Authority (WTA) and the Golden Gate Ferry. Staff’s estimate of the average costs per 

engine horsepower for purchase and installation of a new main and auxiliary dieselfueled engine are shown in Table VIII-2.

Table VIII-2: Estimated Engine Replacement Costs

Engine Category Average Cost ($/hp)A

Propulsion Replacement $ 270

Auxiliary Replacement $ 233

A

Includes engine, labor, and ancillary equipment costs.

Figure VIII-1 and Figure VIII-2 provide the technical basis for the engine replacement 

cost estimates in Table VIII-2. These figures show the relationship between engine 

replacement costs and horsepower. Staff plotted engine costs versus the horsepower 

and the resulting linear equations for main and auxiliary engines are shown in the two 
VIII-5

figures. For main engines, the estimated cost is 270 times the engine horsepower. For 

auxiliary engines, the estimated cost is 233 times the engine horsepower. These 

relationships were used to estimate engine replacement costs for the proposed 

regulation. Engine costs were assumed to increase by 20 percent after 2013 when

U.S. EPA marine engine Tier 3 standards come into effect for the majority of the 

engines. (EMA French)

Figure VIII-1: Propulsion Engine Cost vs. HorsepowerA

Propulsion Engine Costs per Rated Horsepower

y = 270.08x

R

2

 = 0.8641

$-

$200,000

$400,000

$600,000

$800,000

0 500 1000 1500 2000 2500 3000

Rated Power (hp)

Cost ($)

A

Includes engine, labor, and ancillary equipment costs.

Figure VIII-2: Auxiliary Engine Cost vs. HorsepowerA

Auxiliary Engine Costs per Rated Horsepower

y = 233.29x

R

2

 = 0.9513

$-

$20,000

$40,000

$60,000

$80,000

$100,000

0 100 200 300 400 500

Rated Power (hp)

Cost ($)

A

Includes engine, labor, and ancillary equipment costs.
VIII-6

b. Early Replacement Costs

 (i) Residual Value of Engine 

Staff anticipates that most operators of ferries, excursion vessel, tugboat s, and 

towboats will comply with the proposed regulation by replacing existing engines with 

new engines. There will be situations where engines will have to be replaced before the 

end of the engine’s useful service life. In these situations, the costs associated with the 

loss of the residual or remaining value of the engine being replaced is assigned to this 

regulatory action. In situations where the engine is being replaced after the end of the 

useful service life, costs associated with the engine replacement are not assigned to the 

regulation. 

We have used the following two equations to calculate remaining or residual value for 

main and auxiliary engines.

RVM = [$270 * Hp] * [1 – EA/USL] Note: applicable only when EA/UEL < 1.

Where:

RVM is the remaining or residual value of the main engine

Hp is the rated horsepower of the main engine(s)

EA is the engine age in years

USL is the useful service life (see Table VIII-3)

RVA = [$233 * Hp] * [1 – EA/USL] Note: applicable only when EA/UEL < 1

Where:

RVA is the remaining or residual value of the auxiliary engine

Hp is the rated horsepower of the auxiliary engine(s)

EA is the engine age in years

USL is the useful service life (see Table VIII-3)

The cost associated with early engine replacement was determined by estimating the 

remaining residual value of the engine at the time it is required to be replaced. To 

determine this we assumed a linear depreciation of the engine’s value such that the 

remaining (residual) value is zero at the end of the engines useful service life. A graph 

of linear depreciation with an engine with a 30 year useful service life is presented in 

Figure VIII-3.
VIII-7

Figure VIII-3: Linear Depreciation Example for Residual Value

Linear Depreciation

0

25

50

75

100

0 10 20 30 40 50

Time (Years)

% Cost

For this analysis, we have defined the useful service life for harbor craft engines to be 

the 70th percentile engine age on the cumulative engine age distribution curve. In other 

words, the engine age (years old) where 70 percent of the engines are younger than 

this age and 30 percent of the engines are older than this age. In Figure VIII-4, the 

survey ferry/excursion vessel main engine age distribution is shown along with the age 

distribution trend line to smooth out and approximate the statewide population trend.

The 70th percentile was chosen instead of the typical 50th percentile because recent 

Carl Moyer program funding for engine replacements and growth of the industries have 

resulted in a skewing of the age distribution toward more new engines. Choosing the 

70th percentile provided an economic service life that was close to half the total life, 

which is similar to the ideal distribution curve where half the engines are gone by half 

the total life.

Figure VIII-4: Ferry/Excursion Main Engine Population Distribution

Ferry Main Engine Cummulative Age Distribution 

Survey Data

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60 70

Age in CY 2004

% of Total Engine 

Population

Survey Data

Useful Service Life

(70th percentile)

Total Life 

(90th percentile)

Log. (Survey Data)
VIII-8

The total life was chosen in a similar fashion, but the 90th percentile engine age was 

used. In other words, the engine age (years old) where 90 percent of the engines are 

younger than this age and 10 percent of the engines are older than this age. The 

90th percentile age was selected because some engines are kept for an extremely long 

time, usually as a spare or backup with very little use, and would skew the typical total 

life. In the ferry/excursion vessel main engine survey population, a couple engines are 

older than 60 years and extend the age beyond what would be considered normal. The 

trend line crosses the 10 percent of total population grid line (90th percentile) at about an 

age of 40 years and establishes the expected total life of ferry/excursion vessel main 

engines. 

Table VIII-3 presents ARB estimates of the useful service life and total life for main and 

auxiliary engine on ferries, tugboat, and towboats.

Table VIII-3: Estimated Useful Service and Total Life of Used Equipment

Vessel Engine Type Useful Service Life Total Life

Ferry/Excursion Main 21 40

Ferry/Excurasion Auxiliary 20 40

Tugboat Main 25 42

Tugboat Auxiliary 30 45

Towboat Main 34 60

Towboat Auxiliary 35 50

For all of the cost calculations, we assumed that the value of an engine at the end of its 

useful service life was $0 or equal to the removal costs. Presented below is an example 

calculation of the residual value for a main engine in a tugboat with a 15-year-old 

1500 hp main engine that is replaced 10 years before the end of its useful service life of 

25 years.

Main Engine Residual Value = [$270x1500] X [1- 15 years ] = $162,000

 25 years/total life

For this tugboat main engine, the portion of the regulatory cost based on the residual 

main engine costs attributed to compliance with the proposed regulation would be 

$162,000.

 (ii) Residual Value of Engine Rebuild Work 

As with the previous section and discussion of the residual value of the engine, there is 

also a residual value to the most recent engine rebuilds or overhauls. The engine 

overhauls are categorized as either a “major” or “top end” overhaul. The frequency of 

these overhauls can depend on the engine application and the amount of annual use. 

Engines used under high loads and long hours may need to be overhauled more often. 
VIII-9

Most of the ferries, excursion vessels, towboats, and tugboat s appear to have a similar 

overhaul frequency. 

Based on the information received on engine overhauls, the overhaul frequency is 

typically around every 10 years for a major overhaul and 5 years for a top end overhaul. 

For this cost analysis, staff assumed a major overhaul and top end overhaul schedule of 

10 and 5 years, respectively. There will be situations where engines will have to be 

replaced before the end of the engine’s expected overhaul life. In these situations, the 

costs associated with the loss of the residual or remaining value of the engine overhaul 

when the engine is being replaced is assigned to this regulatory action. In situations 

where the engine is being replaced at the end of the overhaul life, costs associated with 

the engine overhaul are not assigned to the regulation.

Staff used the residual value of major and top end engine overhauls as one of the costs 

associated with early engine replacement. To determine this we assumed a linear 

depreciation of the overhaul’s value such that the remaining (residual) value is zero at 

the end of the overhaul’s useful service life. Staff gathered overhaul cost information for 

many engines by contacting owners of boat maintenance and repair facilities. Using 

this information we developed the following two equations to calculate remaining or 

residual value for major and top end engine overhauls. These equations apply to both 

the main and auxiliary engines.

OVM = [$53.93 * Hp +$13641] * [1 – MOA/MOL] 

Note: applicable only when MOA/MOL < 1.

Where:

OVM is the remaining or residual value of the major engine overhaul

Hp is the rated horsepower of the main engine(s)

MOA is the major overhaul age in years

MOL is the major overhaul life (assume 10 years)

OVT = [$16.52 * Hp + $12456] * [1 – TOA/TOL] 

Note: applicable only when TOA/TOL < 1

Where:

OVT is the remaining or residual value of the top end overhaul

Hp is the rated horsepower of the auxiliary engine(s)

TOA is the top end overhaul age in years

TOL is the top end overhaul life (assume 5 years)

c. Fuel Costs 

Fuel costs were not included in this analysis. We anticipate a net fuel savings of 3 to 

5 percent with new engines due to both the electronic engine controls and the lighter 

weight. The slightly lighter new engines produce similar power as the engines being 

replaced and this lighter weight translates into less fuel consumed while traveling 
VIII-10

through the water at a similar vessel speed. Also, since the new engines will be 

electronically controlled, we anticipate fuel savings due to more efficient fuel 

combustion. Fuel costs for new ferries with BACT installed were also not taken into 

account. The added weight and increased back pressure of exhaust emission control 

technologies would increase fuel consumption. Data from the Baylink Vallejo Ferry with 

SCR installed indicates that this increase could be as much as 10 percent. However, 

the number of new ferries added to the fleet in the next 14 years will be small compared 

to the number of Tier 0 and Tier 1 engines repowered with more fuel efficient engines. 

d. Out of service costs 

“Out-of-service” costs can occur when a vessel is removed from service to replace an 

engine(s). Changing out a main engine takes about two to three weeks. Since most 

ferries, tugboat s, and towboats have two propulsion engines, these vessels would be 

out-of-service for 4 to 6 weeks. Staff has not assigned an out-of-service cost for the 

regulation. We assumed that engine replacement for excursion vessels would occur 

during their low use season and not have an impact on revenue. For transit ferries, 

tugboat s, and towboats, we assumed that most companies have sufficient excess 

capacity to schedule engine replacements so as to maintain the current level of service 

and minimize the “out-of-service” cost. An additional factor we considered is that 

companies currently, as a normal business practice, take the vessels out of service 

every five years for an engine overhaul. We believe that the out of service time for a 

repower would replace the out of service time for an overhaul.

e. Operation and Maintenance Costs – Replacement Engines

Based on discussion with engine manufacturers, we do not anticipate that there will be 

any change in the operating and maintenance costs for new engines compared to the 

engines that are being replaced.

f. New Ferry Aftertreatment Costs

The proposed regulation requires that new ferries install BACT to further reduce 

emissions. Staff estimated the cost for aftertreatment system for a new ferry vessel to 

be $170 per engine horsepower. This cost estimate assumes that BACT is likely to be 

a combined PM and NOx system. As such, the $170/hp represents the combination of 

the current cost of a selective catalytic reduction system (SCR) of approximately 

$125/hp and the cost of a diesel particulate filter (DPF) of approximately $45/hp. By 

selecting a combined cost of these two emission reduction systems, staff ensured that 

the cost of aftertreatment system was not underestimated. It should be noted that while 

staff is assuming a combined SCR/DPF system, the actual determination of what BACT 

would be used will be made on a case-by-case basis. Depending on the specifics, 

BACT may be a PM control system, a NOx control system, or a combination PM/NOx 

system.

The installation of aftertreatment systems on new ferries would generate additional 

operating and maintenance costs for these vessels. The additional maintenance costs 
VIII-11

would be cleaning, refurbishing, and periodically replacing the aftertreatment system. 

Additional operating costs would include additional fuel usage due to the added weight 

of the system and increased back pressure to the engine and the cost of urea for an 

SCR system. These costs depend on the technologies used. Staff assumed a DPF 

cleaning cost of $300 per year and a replacement cost of $170/hp every 5 years which 

includes replacement of both DPF and SCR. A 5 year replacement period was based 

on an average annual engine usage of about 1600 hours and a life of twice the typical 

4200 hour warranty period. These costs were calculated for 2009 through 2022 and 

included as regulatory costs. 

The major operating cost for a SCR system is the urea costs. Staff estimated a nominal 

urea cost at about $15,000 per year or a total of about $200,000 over the 2009 through 

2022 time frame. We have not included these costs in our calculation of regulatory 

costs due to uncertainty in what technology will be selected, the actual cost of operating 

the system, and the limited number of new ferries anticipated over the life of the 

regulation. 

g. Monitoring, Recordkeeping, and Reporting Costs

Monitoring cost are the costs associated with the installation of a non-resettable engine 

hour meter that is required by the proposed regulation. An hour meter is standard 

equipment on all new engines and has been for some time. Therefore, we assumed no 

one time or recurring cost for this equipment. Reporting costs for compliance with the 

recordkeeping and reporting requirements in the proposed regulation was assumed to 

be $100 per engine during the first year of the regulation. Staff estimated approximately 

one hour would be needed to collect and send this informationat a pay rate of $100 per 

hour. The ARB staff believes this is a conservative assumption since many companies 

already keep these records. Reporting costs of $100 per engine were also included for 

when a ferry, excursion vessel, tugboat, or towboat engine would be brought into 

compliance. Annual reporting is not required; however, there are occasions specified in 

the propose regulation when reporting would be required. These include the purchase 

of a new engine or vessel, change in engine or vessel ownership, and change in engine 

operating hours. 

2. Future Year Equipment Populations Subject to the Regulatory Requirements

Staff estimated the engine inventory for future years to determine the number of in-use 

engines required to come into compliance in each year. The development of this 

inventory is discussed in Chapter III, Harbor Craft Inventory and Emissions, and 

Appendix B. Staff has used the inventory and emissions model to calculate equipment 

growth, annual use,age distribution, and attrition for the vessel categories. Future year 

equipment populations for each compliance year were evaluated by the inventory model 

to determine the number of engines to be replaced for each compliance year. 

Table VIII-4 presents the expected number of in-use engines per year required to 

comply with the requirements of the regulation. 
VIII-12

The numbers of new ferry propulsion engines required to comply with the BACT 

requirement were estimated using the model based on population growth rates. These 

are also included in Table VIII-4. These numbers are likely to be over-estimated due to 

a current limitation of the model. The ferry and excursion vessel categories were 

combined in the model because separate data for these two categories were not 

available. So, while the requirement that propulsion engines on new ferries have BACT 

installed on them does not apply to excursion vessels, or ferries that carry less than 

75 passengers, it was not possible to separate out these vessels with the current model. 

Staff know of only four new ferries (total of eight propulsion engines), either built or 

planned to be built in the 2004 to 2009 time frame. This indicates that at least half to 

three-fourths of the new ferry engines shown in Table VIII-4 are actually excursion 

vessel engines not subject to the BACT requirement. The initial reporting required by 

the proposed regulation would help staff separate these categories for the future model. 

Table VIII-4: Estimated Population of In-Use Vessel Engines and New Ferry 

Engines Subject to Regulation Emission Limits

Number of In-Use Engines Number of New 

Year Ferry Engines

Auxiliary Propulsion Total Propulsion

2009 38 102 140 7

2010 111 132 243 8

2011 29 24 53 8

2012 23 48 71 7

2013 45 83 128 5

2014 29 40 69 5

2015 53 149 203 3

2016 39 23 62 4

2017 54 113 166 4

2018 54 113 167 4

2019 55 113 168 4

2020 56 113 169 4

2021 47 42 88 4

2022 28 34 63 4

Total 662 1,127 1,789 72

D. Total Regulatory and New Equipment Costs

Table VIII-5 provides the regulatory costs attributed to the in-use engine requirements of 

the proposed regulation. The in-use engine regulatory costs are derived from the 

residual value of the replaced engine, the residual value of the most recent overhaul, 

the time value of money for the earlier than anticipated repower cost, and the reporting 
VIII-13

cost. The first year reporting costs include the cost to all harbor craft operators to 

provide equipment and operating information to ARB. Subsequent year reporting costs 

include the cost of updating the initial information as engines are replaced. The in-use 

vessel total regulatory costs for this regulation over the years 2009 to 2022 are 

estimated to be $123 million. Approximately 57 percent of the total in-use regulatory 

cost is from the ferry and excursion vessels, 36 percent from tugboats, and 7 percent 

from towboats.

Table VIII-5: Estimated Regulatory Costs for In-Use Engine Replacement

Regulatory Costs

Year Auxiliary Main Total

2009 $615,000 $2,063,000 $3,510,000

2010 $416,000 $1,138,000 $1,555,000

2011 $364,000 $1,131,000 $1,495,000

2012 $371,000 $1,864,000 $2,234,000

2013 $923,000 $10,526,000 $11,449,000

2014 $565,000 $5,372,000 $5,937,000

2015 $1,330,000 $23,451,000 $24,782,000

2016 $751,000 $2,014,000 $2,765,000

2017 $928,000 $15,696,000 $16,623,000

2018 $944,000 $14,453,000 $15,397,000

2019 $960,000 $13,210,000 $14,170,000

2020 $976,000 $11,967,000 $12,943,000

2021 $732,000 $4,894,000 $5,626,000

2022 $477,000 $4,075,000 $4,551,000

Total $10,352,000 $111,854,000 $123,038,000

Table VIII-6 provides summaries of the new equipment compliance costs for the

replacement of in-use engines with new engines. The in-use engine new equipment

costs are derived from the capital and installation repowers costs and the reporting cost.

The new equipment costs for repowering an in-use engine are costs that the vessel 

owner would eventually pay, but the proposed regulation requires this service to be 

performed earlier than normal. The first year reporting costs include the cost for all 

harbor craft to provide equipment and operating information to ARB. Subsequent year 

reporting costs include the cost of updating the initial information as engines are 

replaced. The total in-use engine replacement new equipment costs associated with this 

regulation over the years 2009 to 2022 are estimated to be $441 million. Approximately 

68 percent of the total in-use new equipment cost is incurred by the ferry and excursion 

vessel industry, 27 percent by the tugboat industry, and 5 percent by towboat industry.
VIII-14

Table VIII-6: Estimated New Equipment Costs for In-Use Engine Replacement

New Equipment Costs

Year Auxiliary Main Total

2009 $792,000 $17,199,000 $17,991,000

2010 $2,146,000 $14,219,000 $16,366,000

2011 $773,000 $8,540,000 $9,313,000

2012 $622,000 $8,353,000 $8,975,000

2013 $1,395,000 $35,559,000 $36,954,000

2014 $1,098,000 $19,116,000 $20,214,000

2015 $1,795,000 $76,689,000 $78,484,000

2016 $1,147,000 $6,067,000 $7,214,000

2017 $1,719,000 $63,411,000 $65,130,000

2018 $1,781,000 $55,595,000 $57,376,000

2019 $1,842,000 $47,780,000 $49,622,000

2020 $1,903,000 $39,964,000 $41,868,000

2021 $1,600,000 $15,958,000 $17,558,000

2022 $999,000 $13,270,000 $14,269,000

Total $19,612,000 $421,721,000 $441,333,000

Table VIII-7 provides the estimated numbers of the new ferry engines in each year 

(2009-2022) and the resulting costs due to compliance with the BACT requirement of 

the proposed regulation. The regulatory costs and the new equipment costs are the 

same for this requirement. These costs are based on the cost of installing both a DPF 

and an SCR, periodic replacement cost, an estimated annual operating cost for a diesel 

PM emission control system, and a reporting cost. As mentioned earlier, these costs do

not include the ongoing costs for operating an SCR system. 
VIII-15

Table VIII-7: Population and Costs for New Ferry Propulsion Engines

with Aftertreatment

Year Number of 

Propulsion Engines

Regulatory and New 

Equipment Costs

2009 7 $942,000

2010 8 $1,079,000

2011 8 $1,055,000

2012 7 $907,000

2013 5 $726,000

2014 5 $1,605,000

2015 3 $1,495,000

2016 4 $1,553,000

2017 4 $1,480,000

2018 4 $1,204,000

2019 4 $1,204,000

2020 4 $982,000

2021 4 $1,053,000

2022 4 $1,120,000

Total 72 $16,406,000

Total Estimated Capital and Recurring Costs 2009-2022

The total regulatory and new equipment costs for compliance with the proposed 

regulation were estimated using the cost estimates outlined previously. The total 

annual regulatory and new equipment costs for the vessel engines and emission 

controls are provided in Table VIII-8 and Table VIII-9. As shown in Table VIII-8, the 

regulatory costs associated with the proposed regulation are about $140 million and 

range from $2.5 to $26 million per year with an average annual cost of $10 million. As 

shown in Table VIII-9, the new equipment costs associated with the propose regulation 

are about $458 million and range from $9 to $80 million with an average annual cost of 

about $33 million. Approximately 70 percent of the total new equipment cost is incurred 

by the ferry and excursion vessel industry, 25 percent by the tugboat industry, and 

5 percent by towboat industry.
VIII-16

Table VIII-8: Summary of Estimated Total Regulatory Costs for Proposed 

Harbor Craft Regulation

Regulatory Cost

Year Auxiliary Main Total

2009 $615,000 $3,006,000 $4,452,000

2010 $416,000 $2,218,000 $2,634,000

2011 $364,000 $2,187,000 $2,551,000

2012 $371,000 $2,771,000 $3,142,000

2013 $923,000 $11,252,000 $12,175,000

2014 $565,000 $6,977,000 $7,543,000

2015 $1,330,000 $24,947,000 $26,277,000

2016 $751,000 $3,568,000 $4,319,000

2017 $928,000 $17,176,000 $18,103,000

2018 $944,000 $15,767,000 $16,711,000

2019 $960,000 $14,359,000 $15,319,000

2020 $976,000 $12,950,000 $13,926,000

2021 $732,000 $5,947,000 $6,679,000

2022 $477,000 $5,195,000 $5,672,000

Total $10,352,000 $128,320,000 $139,504,000

Table VIII-9: Summary of Estimated Total New Equipment Costs for 

Proposed Harbor Craft Regulation

New Equipment Costs

Year Auxiliary Main Total

2009 $792,000 $18,141,000 $18,933,000

2010 $2,146,000 $15,299,000 $17,445,000

2011 $773,000 $9,596,000 $10,369,000

2012 $622,000 $9,261,000 $9,883,000

2013 $1,395,000 $36,286,000 $37,681,000

2014 $1,098,000 $20,721,000 $21,819,000

2015 $1,795,000 $78,184,000 $79,980,000

2016 $1,147,000 $7,621,000 $8,768,000

2017 $1,719,000 $64,891,000 $66,610,000

2018 $1,781,000 $56,909,000 $58,690,000

2019 $1,842,000 $48,928,000 $50,770,000

2020 $1,903,000 $40,947,000 $42,850,000

2021 $1,600,000 $17,011,000 $18,611,000

2022 $999,000 $14,391,000 $15,390,000

Total $19,612,000 $438,187,000 $457,799,000
VIII-17

E. Estimated Costs to Businesses

The costs and economic impacts on businesses are presented in this section. The 

overall impact on business competitiveness, employment, and other impacts on 

business are also presented.

1. Potential Business Impacts Based on Change to ROE

Staff’s analysis of the potential impacts of the proposed regulation on businesses in 

California was based on a comparison of the ROE for affected businesses before and 

after the inclusion of the regulatory costs. The analysis used publicly available 

information to assess the impacts on competitiveness, jobs, and business expansion, 

elimination, or creation. From the limited financial data staff obtained on ferry, 

excursion vessel, tugboat, and towboat owners, none of these companies would be 

considered a small business bases on the definition of a small business per California 

Government Code Section 11342.610 (annual gross receipts of $1,500,000 or less for

transportation and warehousing). There may be some ferry, excursion vessel, tugboat, 

and towboat vessel owners that could be considered a small business, but ARB was 

unable to identify them due to a lack of financial data. Staff expects that tugboat and 

towboat businesses would not be considered a small business and within the ferry and 

excursion businesses, only the smaller excursion vessel business may fall into that 

classification. 

The types of businesses that the proposed regulation will have an economic impact on 

are those that own ferries, excursion vessels, tugboats, and towboats. Other types of 

businesses that will be slightly impacted by the reporting cost requirements are 

businesses that own commercial fishing, charter, work, pilot, crew and supply vessels 

and other commercial harbor craft. Based on the ARB Survey, staff estimates that there 

are approximately 300 ferry, excursion vessel, tugboat, and towboat businesses that will 

be affected by this regulation beyond simply complying with the reporting requirements.

The ROE approach used in evaluating the potential economic impact of the proposed 

regulation on California businesses is as follows:

(1) Affected businesses were identified from responses to the ARB survey. ARB staff 

selected a total of nine companies with some financial data, three companies from 

each affected type of business representing ferry/excursion vessel, tugboat, and 

towboat.

(2) The cost for compliance was estimated and averaged over the years a particular 

company was affected.

(3) The total annual cost for each business was adjusted for both federal and states 

taxes. 
VIII-18

(4) These adjusted costs were subtracted from net profit data, either actual net profit 

from Dun and Bradstreet or industry averages applied to the number of 

employees, and the results used to calculate the Return on Owners' Equity 

(ROE). The resulting ROE was then compared with the ROE before the 

subtraction of the adjusted costs to determine the impact on the profitability of the 

businesses.

Using Dun and Bradstreet financial data when data were available, staff calculated the 

ROEs, both before and after the subtraction of the adjusted annual costs, for the typical 

businesses from each industry category. These calculations were based on the

following assumptions.

• A selected business in each category of ferry/excursion, tugboat, and towboat is 

representative of a typical business in that category.

• All affected businesses are subject to federal and state tax rates of 35 percent and 

9.3 percent, respectively.

• Affected businesses are neither able to increase the prices of their services nor 

lower their costs of doing business through cost-cutting measures.

These assumptions, though reasonable, might not be applicable to all affected 

businesses.

As shown in Table VIII-10, the average ROE of the sample businesses in the categories

listed changed by about 2.5 percent. The decline in profitability was highest for 

ferries/excursion vessels and tugboats (3.4 percent and 3.6 percent) and lowest for 

towboats (0.5 percent). These businesses, however, are unlikely to have to absorb the 

entire cost of this regulation. To the extent that they are able to pass on the cost of the 

regulation, the impact on their profitability would be less than estimated here. Thus, 

staff expects most affected businesses to be able to absorb the cost of the regulation 

with no significant impact on their profitability. However, it is likely that some small 

businesses may be affected significantly. The change in ROE is expected to be larger 

for small businesses, especially ferries and excursion.

Table VIII-10: Typical Affected Businesses with Change in ROE

Category ROE % 

Change

Ferry/Excursion -3.4%

Tugboat -3.6%

Towboat -0.5%

Average -2.5%

These businesses may be able to reduce the impact of the regulation on their 

businesses by taking advantage of available public funding. The costs impacts 
VIII-19

presented here do not taken into consideration the impact of incentive or grant funding. 

Publicly owned ferries are often eligible for both State and Federal transportation related 

grants. Moyer Program funding is a potential funding source for companies that comply 

early or achieve emission reductions beyond the regulation. We also anticipate Bond 

Funds to be available for goods movement related vessels like tugboats and towboats.

2. Potential Impact on Employment, Business Creation, Elimination or 

Expansion

a. Potential Impact on Employment

The proposed regulation is not expected to cause a noticeable change in California 

employment and payroll. According to the 2005 Economic Census, California 

employment in the inland water transportation industry (NAICS 48321), which includes 

establishments engaged in providing inland water transportation of passengers and/or 

cargo on lakes, rivers, or intra-coastal waterways) was 519 in 2005, or about 10 percent 

of the employment in the water transportation industry. This also represents only about 

0.1 percent of the total transportation and warehousing jobs in California. These 

employees working in 33 establishments generated about $23 million in payroll, 

accounting for about 0.1 percent of total California transportation and warehousing 

payroll in 2005. Sixty establishments had 20 employees or more; the rest had less than 

20 employees each. 

The employment in the inland water transportation industry is unlikely to change 

significantly as a result of the proposed regulation. This is because most affected 

businesses are likely to be able to pass on the regulation cost to their customers in 

terms of higher service fees. The staff‘s profitability analysis shows that the impact on 

business profitability is minor even if the affected businesses absorb the entire cost of 

the proposed regulation.

The proposed regulation, however, is likely to increase employment in businesses that 

make, sell, install and maintain marine engines and DPF and SCR devices. 

b. Potential Impact on Business Creation, Elimination or Expansion

The proposed regulation would have no noticeable impact on the status of California 

businesses. This is because the regulation costs are not expected to impose a 

significant impact on the profitability of businesses in California. However, some small 

businesses with little or no margin of profitability may lack the financial resources to 

comply in a timely manner. These businesses may be able to take advantage of 

available public funding such as Carl Moyer program to ameliorate the impact of the 

proposed.

While some individual businesses may be affected adversely, the proposed regulation 

may provide business opportunities for existing California businesses or result in the 

creation of new businesses. California businesses that make, install, and service 
VIII-20

marine engines and DPF and SCR devices to affected harbor craft businesses may 

benefit from increased harbor craft business spending on compliance. 

c. Potential Impact on Business Competitiveness 

The proposed regulation would have no significant impact on the ability of California 

businesses to compete with businesses in other states. Because ferries, tugboats and 

towboats operate locally and are not subject to competition from similar businesses 

operating out-of state. 

F. Potential Costs to Local, State, and Federal Agencies

This proposed regulation directly affects local, State, or Federal agencies. It will result 

in increased costs for those public agencies that own ferries, excursion vessels, 

tugboats, or towboats. Those public agencies owning or operating harbor craft other 

than ferries, excursion vessels, tugboats, or towboats, will have an insignificant cost 

impact to comply with the proposed regulation. The calculated costs are shown in 

Table VIII-11. In this table, the “Regulatory Costs” and “Reporting Costs” are attributed 

to the regulation. The “New Equipment Costs” are, as discussed earlier, the total out-ofpocket cost for purchasing and installing the replacement engine. There would be 

significant costs to the ARB to implement and enforce the regulation. Staff estimates 

that ARB’s cost to implement the reporting program (initial report) would be 

approximately $25 to $50 per engine. An additional annual cost of $10 to $100 per 

engine (after the first year) is estimated to cover an inspection and report update at the 

time of final compliance with the regulation. These total costs are estimated to be 

$200,000 to $600,000 for the regulation. The ARB’s administrative costs for outreach, 

educational efforts, and technical assistance would be absorbed within existing budgets 

and resources. 
VIII-21

Table VIII-11: Costs to Local, State, and Federal Agencies

Area Agency Regulatory 

Costs

New 

Equipment

Out-ofPocket Total

# of 

Engines 

Reporting

Reporting 

Cost

U.S. Dept. of Commerce / CINMS 5 $500

U.S. National Park Service 1 $100

Federal

Total 6 $600

City of Alameda 8 $800

City of Long Beach 9 $900

City of Los Angeles 3 $300

City of Oakland 3 $300

City of Vallejo 4 $400

City of Vallejo / Blue & White 

Fleet $814,894 $6,288,150 12 $1,200

Golden Gate Bridge Hwy 

Transportation Dist. $2,350,830 $10,459,107 28 $2,800

Mt. Diablo Unified School District 3 $300

Port of Los Angeles $37,063 $91,108 28 $2,800

San Joaquin Co. 6 $600

Santa Cruz Port Dist. 1 $100

Local

Total $3,202,787 $16,838,365 105 $10,500

CA Dept. of Transportation $183,725 24 $2,400

CA. Dept. of Fish & Game 8 $800

San Francisco State University 2 $200

San Jose State University 4 $400

State of CA, Parks Department 5 $500

State

Total $183,725 43 $4,300

G. Cost-Effectiveness

In this section, the cost-effectiveness of the regulation is estimated. Cost-effectiveness 

is expressed in terms of control costs (dollars) per unit of air emissions reduced (tons or 

pounds). As described below, for example, the cost-effectiveness for the proposed 

regulation is determined by dividing the total cost of the proposed regulation by the total 

pounds of diesel PM emissions reduced during the years 2009 to 2022. All costs are in 

2006 equivalent expenditure dollars.

1. Expected Emission Reductions

Staff estimated the projected total emission reductions under the regulation using the 

statewide inventory. The following Table VIII-12 provides a summary of the annual 

statewide diesel PM and NOx reductions that will result from the proposed regulation. 

This regulation is expected to reduce almost 5 million pounds of diesel PM and 

39 thousand tons of NOx by 2022. Table VIII-13 provides a breakdown of the annual 

statewide diesel PM and NOx reductions by vessel type that will result from the 

proposed regulation. 
VIII-22

Table VIII-12: Statewide Diesel PM and NOx Annual Emission Reductions

from 2009 to 2022

PM Reduction (pounds/year) NOx Reduction (tons/year) Year Aux Main Total Aux Main Total

2009 1,600 57,600 59,200 11 514 525 

2010 2,800 68,600 71,400 22 637 659 

2011 6,700 104,100 110,800 57 1,029 1,085 

2012 6,800 102,700 109,500 58 1,032 1,090 

2013 8,300 210,900 219,200 67 2,060 2,127 

2014 8,800 228,800 237,600 70 2,096 2,166 

2015 12,200 494,600 506,800 88 4,413 4,501 

2016 12,400 458,900 471,300 86 3,973 4,059 

2017 15,100 562,000 577,100 93 4,580 4,672 

2018 14,400 536,500 550,900 86 4,200 4,285 

2019 13,500 501,000 514,500 77 3,765 3,843 

2020 12,600 509,300 521,900 68 3,668 3,735 

2021 10,800 480,600 491,400 53 3,340 3,393 

2022 9,200 415,600 424,800 40 2,774 2,814 

Total 135,200 4,731, 200 4,866,400 876 38,078 38,955 

Table VIII-13: Statewide Diesel PM and NOx Annual Emission Reductions 

by Vessel Type

Ferries Towboats Tugboats

Year PM

 (lbs/yr)

NOx 

(tons/yr)

PM

 (lbs/yr)

NOx 

(tons/yr)

PM

 (lbs/yr)

NOx 

(tons/yr)

2009 11,500 100 11,200 94 36,500 330 

2010 12,500 120 13,400 110 45,400 430 

2011 21,500 220 13,800 120 75,400 750 

2012 24,300 250 12,700 110 72,600 730 

2013 102,300 980 11,900 110 105,000 1,040 

2014 126,200 1,100 10,200 94 101,200 980 

2015 290,400 2,500 50,400 470 166,100 1,560 

2016 267,000 2,200 47,700 440 156,600 1,440 

2017 355,000 2,700 52,100 460 170,000 1,500 

2018 334,000 2,400 50,800 440 166,100 1,420 

2019 317,500 2,200 50,600 440 146,400 1,190 

2020 331,900 2,300 58,500 490 131,600 970 

2021 309,300 2,100 59,400 490 122,700 840 

2022 256,500 1,600 58,100 470 110,300 730 

Total 2,759,900 20,770 500,800 4,338 1,605,900 13,910

Note: Slight difference between Table VIII-12 and Table VIII-13 emissions totals are due to rounding.
VIII-23

2. Cost-Effectiveness

To determine the cost-effectiveness of the proposed regulation, the sum of the annual 

costs (2009 to 2022) for the proposed regulation were divided by the diesel PM 

emission reductions over the same time period attributable to the regulation. The 

summed 2009 to 2022 costs are based on the regulatory costs. The regulatory costs 

include the remaining value of the engine being replaced (engine, supporting 

equipment, and installation labor), the residual value of the most recent maintenance, 

emission control devices on new ferry main engines, and recordkeeping and reporting. 

The estimated overall cost-effectiveness (total PM reduced divided by total regulatory 

costs) is $29 per pound of diesel PM reduced, if all the costs of compliance are 

allocated to diesel PM reduction. 

Since the regulation will also result in reductions in oxides of nitrogen (NOx) emissions, 

staff conducted a second cost-effectiveness analysis in which half of the cost of 

compliance was allocated to PM benefits and half the cost was allocated to NOx 

benefits. This results in cost-effectiveness values of $14.50/lb diesel PM and 

$1,800/ton of NOx. 

A third method to express cost effectiveness is to use the sum of the combined PM and 

NOx reductions (approximately 83 million pounds). Using this approach, the resulting 

cost effectiveness for the proposed regulation is about $1.70 per pound of PM and NOx 

reduced. These cost-effectiveness values are presented in Table VIII-14.

Table VIII-14: Summary of Average Cost-Effectiveness for the Period 2009-2022

Emissions Total Regulatory Cost

2009 – 2022

Total Emissions Reduced 

2009 - 2022

Total CostEffectiveness

All costs assigned to PM 

PM $140,000,000 4,900,000 lbs $29/lb

Divide Costs Equally Between PM and NOx

PM $70,000,000 4,900,000 lbs $14.50/lb

NOx $70,000,000 39,000 tons $1,800/ton

Combine PM and NOx Emissions

PM + NOx $140,000,000 83,000,000 lbs $1.70/lb

All values rounded

As shown in Table VIII-15, the cost-effectiveness of the proposed regulation is in the 

range of other regulations recently adopted by the Board. For example, the diesel PM 

cost-effectiveness of the solid waste collection vehicle rule was estimated at $28 per 

pound, excluding the benefits of NOx and hydrocarbon reductions (ARB, 2003a). The 

cost-effectiveness of the stationary diesel engine airborne toxic control measure 

(ATCM) was estimated to range from $4 to $26 per pound of diesel PM reduced 

(ARB,2003b). Finally, the transport refrigeration unit ATCM was estimated to have a 

cost-effectiveness of $10 to $20 per pound of diesel PM reduced (ARB, 2003c). 
VIII-24

Table VIII-15: Diesel PM Cost-Effectiveness of the Proposal and Other 

Regulations/Measures (Attributes All Costs to Each Pollutant 

Individually)

Regulation or Diesel PM Cost- Effectiveness

Airborne Toxic Control Measure Dollars/ Pound PM

Commercial Harbor Craft $29

In-Use Off-Road Diesel Vehicles $40

Cargo Handling Equipment Proposal $41

Solid Waste Collection Vehicle Rule $28

Stationary Diesel Engine ATCM $4 - $26

Transport Refrigeration Unit ATCM $10 - $20

H. Availability of Incentive Funding

Incentive programs have the ability to achieve emissions reductions early or beyond 

those required by regulations. California has one of the largest clean air incentive 

programs in the nation – the Carl Moyer Program – with up to $140 million available 

each year through State and local funds. 

Even so, this level of funding is far from sufficient to pay for all the reductions needed to 

provide clean air. Reductions required by regulations, and funded by owners of the 

affected vehicles and equipment, must continue to provide the majority of emission 

reductions. Incentive programs, such as the Carl Moyer Program, fund the incremental 

cost of cleaner-than-required engines, equipment, and other sources of pollution 

providing early or extra emission reductions. Carl Moyer Program emission reductions 

are credited in California’s State Implementation Plan and must be real, surplus to 

regulatory requirements, quantifiable, and enforceable.

The Carl Moyer Program is implemented as a partnership between ARB and the local 

air districts. The ARB provides program oversight and minimum program requirements 

and the local air districts select and fund projects. Statewide, the Carl Moyer Program 

has been oversubscribed every year, and this continues to be the case today. Eligible 

marine vessel projects compete with on-road, off-road, agricultural pump, locomotive, 

and other projects for funding. 

Since its inception, the Carl Moyer Program has provided significant funding to replace 

older, high-emitting harbor craft engines with newer, cleaner engines. Most funding has 

gone towards fishing vessels, followed by tugboats, and ferry and excursion vessels. 

Fishing vessel grants have averaged about $35,000 per engine repower, while tugboat 

and ferry/excursion vessel grants have averaged about $93,000 and $125,000 per 

engine repower, respectively. Marine vessel repowers through the Carl Moyer program 

have been very cost-effective, averaging about $1,800 per ton of NOx reduced, with a 

typical project life of over ten years.
VIII-25

To date, no retrofit devices (such as diesel particulate filters) have been ARB- or 

U.S. EPA-verified to reduce emissions from marine vessels. For this reason, these 

devices for use on harbor craft are not yet eligible for Carl Moyer Program funds. 

Similarly, new harbor craft have not received program funding since only vessels 

certified to be at least 30 percent cleaner for NOx emissions than existing (Tier 2) 

U.S. EPA marine engine standards are eligible for funding, and no vessels have been 

certified as such to date. If a vessel were to be ARB- or U.S. EPA-certified to this 

cleaner-than-required emission rate, it would potentially be eligible for Carl Moyer 

Program funding.

The Carl Moyer Program has a minimum three year project life, meaning that incentive 

funds cannot be used to pay for a project within three years of its compliance deadline. 

Therefore, vessel engines with earlier compliance dates will have limited opportunity for 

funding. Regulated vessel engines with later compliance dates have a longer window of 

eligibility for funding. Engine repowers on vessels not subject to the in-use engine 

compliance requirements of the proposed regulation -- including fishing vessels, crew 

and supply vessels, work vessels, and others – continue to provide surplus emission 

reductions and remain eligible for Carl Moyer Program funds.

The proposed commercial harbor craft regulation has differing implementation timelines 

for vessels with homeport in the SCAQMD and those outside of the SCAQMD. Table 

VIII-16 and Table VIII-17 summarize the date by which commercial harbor craft projects 

must be complete to be eligible for Carl Moyer Program funding in both of these areas. 

In the case of engine repowers, the Moyer Project Completion Deadline reflects the 

date by which the new vessel engine must be installed and operational. In addition, 

project life for an engine cannot extend beyond that engines compliance deadline. For 

example, a 1980 model year engine operating 750 hours annually that is installed in 

December 2008 has a compliance deadline of December 31, 2012 and therefore would 

have a maximum project life of four years. 

Table VIII-16: Carl Moyer Program Project Completion Deadline for In-Use 

Ferries, Excursion Vessels, Tugboats, and Towboats, Except those 

with Homeport in the SCAQMD

Engine Model Year Total Annual Hours 

of Operation

Proposed Rule 

Compliance Deadline

Moyer Project 

Completion Deadline

Pre-1975 =1500 12/31/ 2009 No funds available

Pre-1975 300-1500 12/31/2010 12/31/2007

1976-1985 = 1500 12/31/2011 12/31/2008

1976-1985 300-1500 12/31/2012 12/31/2009

1986-1995 = 1500 12/31/2013 12/31/2010

1986-1995 300-1500 12/31/2014 12/31/2011

1996-2000 = 1500 12/31/2015 12/31/2012

1996-2000 300-1500 12/31/2016 12/31/2013

2001-2002 = 300 12/31/2017 12/31/2014

2003+ =300 12/31/2018 12/31/2015
VIII-26

These tables reflect requirements for ferries, excursion vessels, tugboats, and towboats 

only. As mentioned earlier, the proposed regulation does not require other vessels to 

reduce emissions; other vessels therefore continue to provide surplus emission 

reductions and are potentially eligible for Carl Moyer Program funding.

Table VIII-17: Carl Moyer Program Project Completion Deadline for In-Use 

Ferries, Excursion Vessels, Tugboats, and Towboats with 

Homeport in the SCAQMD

Engine Model Year Proposed Rule Compliance 

Date

Moyer Project Completion 

Deadline

Pre-1979 12/31/ 2009 No funds available

1980-1985 12/31/2010 12/31/2007

1986-1990 12/31/2011 12/31/2008

1991-1995 12/31/2012 12/31/2009

1996-2000 12/31/2013 12/31/2010

2001 12/31/2014 12/31/2011

2002 12/31/2015 12/31/2012

2003 12/31/2016 12/31/2013

2004 12/31/2017 12/31/2014

2005 12/31/2018 12/31/2015

Since State law requires Carl Moyer Program emission reductions be real, quantifiable, 

enforceable, and surplus to regulatory requirements, the following criteria apply to 

engines subject to the proposed rule:

• Harbor craft engines receiving a rule compliance extension are ineligible for Carl 

Moyer Program funding during the compliance extension period. 

• Harbor craft engines demonstrating compliance with the regulation through an 

Alternative Control of Emissions (ACE) are ineligible for Carl Moyer Program 

funding. 

• Engines that demonstrate rule compliance through a mechanism other than 

engine replacement or installation of an ARB- or U.S. EPA-verified retrofit device 

are not eligible for Carl Moyer Program funding. 

• To ensure project eligibility is not based on a Carl Moyer Program-funded 

compliance extension, vessel engines rebuilt to a Tier 1 or cleaner emission 

standard with Carl Moyer Program funds prior to January 1, 2008 shall use the 

engine date (rather than the date of remanufacture) to determine funding 

eligibility and project life. 

• Barges which are not self-propelled are not considered a ‘mobile source’ and are 

therefore ineligible for Carl Moyer Program funding.

In November 2006, California voters approved $1 billion in incentive funding to reduce 

emissions from goods movement activities (Proposition 1B). Enabling legislation is 

required before these funds can be made available to ARB, and may provide additional 

direction regarding fund project categories and funding recipients. Bond funding 

directed to commercial harbor craft could impact when and how Carl Moyer Program 
VIII-27

funds are made available to avoid overlap between potentially similar incentive 

programs.

I. Analysis of Alternatives

In this section, the cost-effectiveness of the proposed regulation is compared to two 

alternative control options. Both alternatives use a single in-use compliance schedule 

for the entire state. The first alternative analyzed would bring all in-use harbor craft 

engines into compliance on the proposed statewide schedule. The other alternative is 

to use the proposed accelerated SCAQMD compliance schedule for the entire state. 

The first alternative results in a slightly lower regulatory cost, but does not provide the 

needed early emissions reductions for the SCAQMD. The second alternative would 

achieve greater emission reductions and associated health benefits. However, the cost 

of this alternative would be higher and it would present a problem with the ability of the 

State’s existing boat building, repair, and yard facilities to absorb the increased work 

load. The cost effectiveness of all three options are very similar. 

Alternative 1: Remove the SCAQMD Accelerated Compliance and Require the 

SCAQMD to Follow the Statewide Compliance Schedule

For alternative 1, vessels throughout the State would be subject to the 15 year life 

compliance schedule. Vessels with homeports in the SCAQMD would not be subject to 

the accelerated, 13 year life, compliance schedule. The numbers of propulsion and 

auxiliary engines that would be replaced per year with the proposal and the two 

alternatives are shown in Table VIII-18. The estimated regulatory cost of this 

alternative, $135 million, is shown in Table VIII-19, and the new equipment cost, 

$463 million, is shown in Table VIII-20. The regulatory cost is about $4 million less than 

that for the proposed regulation due to the delayed replacement of engines in the 

SCAQMD. The new equipment cost is slightly higher than that for the proposed 

regulation due to the increased number of Tier 3 engines purchased after 2014. The 

total PM emissions reduced with this alternative would be about 10 percent less than 

with the proposed schedule, 4.4 million pounds over the 14 years from 2009 to 2022, as 

shown in Table VIII-21. The resulting cost-effectiveness for this alternative is slightly 

higher than the proposed regulation, $30 per pound of diesel PM reduced. The total 

NOx reduction over this same time period would be 36,000 tons. The resulting cost 

effectiveness, dividing the cost equally between PM and NOx, would be $15 per pound 

of diesel PM reduced and $1,860 per ton of NOx reduced. The cost effectiveness 

comparison is shown in Table VIII-22.

This alternative would slow down engine replacements in the SCAQMD. The engine 

replacement comparison for both alternatives is shown in Table VIII-18. This alternative 

does not provide the early reductions needed to help meet the South Coast Air Basin’s

PM2.5 attainment goals by 2014. The proposed accelerated schedule for the SCAQMD 

provides an additional 300,000 pounds of PM and 2,700 tons of NOx over the 2009 to 

2014 time period, as shown in Table VIII-23 and in Figure VIII-5 and Figure VIII-6. This 

alternative is not as beneficial for air quality as the proposed regulation.
VIII-28

Table VIII-18: Statewide Annual In-Use Engine Replacements

Number of Propulsion Engines Number of Auxiliary Engines Year

Reg Alt 1 Alt 2 Reg Alt 1 Alt 2

2009 102 88 132 38 20 81

2010 132 115 156 111 109 106

2011 24 27 23 29 34 12

2012 48 57 25 23 24 23

2013 83 26 191 45 11 82

2014 40 22 48 29 24 53

2015 149 180 137 53 62 64

2016 23 32 138 39 58 64 

2017 113 164 139 54 78 64 

2018 113 72 140 54 35 65

2019 113 94 60 55 34 68

2020 113 140 49 56 65 40

2021 42 60 0 47 68 0

2022 34 49 0 28 40 0

Total 1,127 1,127 1,238 662 662 720 

Table VIII-19: Statewide Annual Regulatory Costs for In-Use Repowers and 

New Ferry Emission Controls

Regulatory Cost

Year

Reg Alt 1 Alt 2

2009 $4,452,000 $3,085,000 $6,789,000

2010 $2,634,000 $1,901,000 $3,057,000

2011 $2,551,000 $3,025,000 $2,465,000

2012 $3,142,000 $2,413,000 $3,545,000

2013 $12,175,000 $2,743,000 $31,798,000

2014 $7,543,000 $3,563,000 $9,273,000

2015 $26,277,000 $30,483,000 $26,189,000

2016 $4,319,000 $5,358,000 $24,000,000

2017 $18,103,000 $25,842,000 $21,813,000

2018 $16,711,000 $11,563,000 $19,625,000

2019 $15,319,000 $12,43,000 $10,878,000

2020 $13,926,000 $16,166,000 $8,724,000

2021 $6,679,000 $9,131,000 $1,053,000

2022 $5,672,000 $7,591,000 $1,121,000

Total $139,504,000 $135,284,000 $170,333,000
VIII-29

Table VIII-20: Statewide Annual New Equipment Compliance Costs for 

In-Use Repowers and New Ferry Emission Controls

New Equipment Compliance Costs

Year

Reg Alt 1 Alt 2

2009 $18,933,000 $16,028,000 $28,050,000

2010 $17,445,000 $13,403,000 $20,979,000

2011 $10,369,000 $12,218,000 $7,726,600

2012 $9,883,000 $10,172,000 $7,729,000

2013 $37,681,000 $10,095,000 $93,525,000

2014 $21,819,000 $9,070,000 $23,856,000

2015 $79,980,000 $94,768,000 $78,245,000

2016 $8,768,000 $11,696,000 $69,150,000

2017 $66,610,000 $97,988,000 $60,050,000

2018 $58,690,000 $43,826,000 $50,952,000

2019 $50,770,000 $43,172,000 $25,684,000

2020 $42,850,000 $52,736,000 $20,718,000

2021 $18,611,000 $26,517,000 $1,053,300

2022 $15,390,000 $21,650,000 $1,120,700

Total $457,799,000 $463,339,000 $488,835,000

Table VIII-21: Statewide Annual PM and NOx Emission Reductions

PM Reductions (pounds) NOx Reductions (tons)

Year

Reg Alt 1 Alt 2 Reg Alt 1 Alt 2

2009 59,279 46,158 94,251 525 403 849 

2010 71,338 44,657 136,464 659 384 1,332 

2011 110,709 98,945 139,199 1,085 963 1,385 

2012 109,509 94,103 147,666 1,090 922 1,509 

2013 219,218 117,951 501,494 2,127 1,179 4,780 

2014 237,600 106,905 594,113 2,166 1,081 5,178 

2015 506,801 446,323 658,384 4,501 4,164 5,356 

2016 471,335 413,524 617,624 4,059 3,743 4,872 

2017 577,086 589,948 546,537 4,672 4,928 4,067 

2018 550,903 538,012 591,537 4,285 4,324 4,273 

2019 514,457 489,174 588,562 3,843 3,779 4,099 

2020 521,960 518,084 535,867 3,735 3,831 3,541 

2021 491,391 500,452 470,245 3,393 3,594 2,913 

2022 424,874 439,360 388,534 2,814 3,072 2,175 

Total 4,866,459 4,443,595 6,010,479 38,955 36,367 46,326 
VIII-30

Table VIII-22: Summary of Average Cost-Effectiveness for the Period 2009-2022

Emissions Regulatory

2009 – 2022

Alternative 1

2009 - 2022

Alternative 2

2009 - 2022

All costs assigned to PM

PM $28.7 /lb $30.4 /lb $28.3 /lb

Divide Costs Equally Between PM and NOx

PM $14.3 /lb $15.2 /lb $14.2 /lb

NOx $1,790 /ton $1,860 /ton $1,840 /ton

Combine PM and NOx Emissions

PM + NOx $1.7 /lb $1.75 /lb $1.7 /lb

 All values rounded

Table VIII-23: Additional PM and NOx Emission Reductions in the SCAQMD with 

the Regulation Instead of Alternative 1

PM Reductions (pounds) NOx Reductions (tons) Year

Auxiliary Propulsion Total Auxiliary Propulsion Total

2009 1,109 12,012 13,121 8 114 122 

2010 1,560 25,121 26,681 13 262 275 

2011 568 11,196 11,764 5 117 123 

2012 467 14,940 15,406 4 164 168 

2013 2,157 99,110 101,267 14 933 948 

2014 2,753 127,943 130,696 17 1,067 1,085 

Total 8,614 290,321 298,935 62 2,658 2,720 
VIII-31

Figure VIII-5: SCAQMD Annual PM Emissions

South Coast Commercial Harbor Craft PM Emissions

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

2004 2007 2010 2013 2016 2019 2022 2025

Calendar Year

Tons/day

Baseline

Controlled with accelerated schedule for SC

Controlled with statewide schedule

Figure VIII-6: SCAQMD Annual NOx Emissions

South Coast Commercial Harbor Craft NOx Emissions

0

2

4

6

8

10

12

14

16

18

20

2004 2007 2010 2013 2016 2019 2022 2025

Calendar Year

Tons/day

Baseline

Controlled with accelerated schedule for SC

Controlled with statewide schedule
VIII-32

Alternative 2: Accelerate the State compliance schedule to match the SCAQMD

For alternative 2, the whole state of California would be subject to the same accelerated 

compliance schedule as the SCAQMD which would result in many engines replaced 

earlier than the proposed regulation. The estimated cost of this alternative regulation to 

the equipment owners is greater than the proposed regulation and the cost impacts the 

rest of the state two years earlier. As shown in Table VIII-19 and Table VIII-20, both the 

estimated regulatory and new equipment compliance costs for this alternative are about 

$30 million higher than the costs for the proposed regulation. These costs are 

approximately $170 million for regulatory and $489 million for new equipment 

compliance costs over the 14 years from 2009 to 2022. The additional PM and NOx 

reductions associated with this alternative, as shown in Table VIII-21, would be about 

1 million pounds PM and 7,000 tons of NOx compared to the proposed regulation. This 

alternative results in earlier reductions for the rest of the state, but has no additional 

emission benefits for the SCAQMD beyond that provided by the proposed regulation. 

The cost-effectiveness for this alternative is essentially the same as that with the 

proposed regulation at $28.3 per pound of diesel PM reduced, as shown above in

Table VIII-22.

While this option achieves the emission reduction goals outlined in the Goods 

Movement Plan, this plan would exceed California’s boat yard and maintenance 

facilities capabilities. This alternative, with an accelerated statewide compliance 

schedule, would increase the maximum number of propulsion engine repowers for a 

single year to about 190. The ARB staff contacted over 50 California boat yard and 

maintenance facilities in the State and estimate that the State repower capacity is 

between 217 to 271 engine repowers per year. Additional industry capacity is required 

for repowers due to natural engine attrition, the use of incentive funds, and regularly 

scheduled and emergency marine engine maintenance requirements. ARB staff 

believes that more than 150 repowers annually is the practical capacity limit. If the 

entire state were on the proposed SCAQMD compliance schedule and if all ferries, 

excursion vessels, tugboats, and towboats opted for the repower option, the State’s 

capacity to do this work in would be exceeded.

The average time needed to complete a propulsion engine replacement is two to three 

weeks per engine. Since the ARB survey indicates that most ferries, excursion vessels,

tugboats, and towboats have two propulsion engines, a typical repower may take four to 

six weeks or longer. These shipyards need capacity to perform engine repowers 

funded through incentive programs for early emission reductions and the proposed 

auxiliary engine replacements. This second alternative further increases the number of 

vessels complying early, restricting the amount of time and money from funding 

sources, such as the Moyer Program and Bond funding. Also, the additional early 

expenses for businesses reduce their ability to spread the compliance cost over the 

proposed time. Based on these reasons, staff does not recommend this alternative. 
VIII-33

REFERENCES:

(ARB, 2003a) Air Resources Board, Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking, Proposed Diesel Particulate Matter Control Measure for OnRoad Heavy-Duty Residential and Commercial Solid Waste Collection Vehicles, June, 

2003.

(ARB, 2003b) Air Resources Board, Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking, Airborne Toxic Control Measure for Stationary CompressionIgnition Engines, September, 2003.

(ARB, 2003c) Air Resources Board, Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking, Airborne Toxic Control Measure for In-Use Diesel-Fueled 

Transport Refrigeration Units (TRU) and TRU Generator Sets, and Facilities Where 

TRUs Operate, October, 2003.

(EMA French) At a public workshop, on April 12, 2007 in Conference Room 230 at 

Cal/EPA Headquarters, Tim French, representing EMA, commented on the phone that 

Tier 3 marine engines are expected to cost 20% more than Tier 2 engines.