Control of Emissions From Nonroad Spark-Ignition Engines and Equipment

Federal RegisterOct 8, 2008

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9, 60, 80, 85, 86, 89, 90, 91, 92, 94, 1027, 1033, 1039, 1042, 1045, 1048, 1051, 1054, 1060, 1065, 1068, and 1074

[EPA-HQ-OAR-2004-0008; FRL-8712-8]

RIN 2060-AM34

Control of Emissions From Nonroad Spark-Ignition Engines and Equipment

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

We are setting emission standards for new nonroad spark-ignition engines that will substantially reduce emissions from these engines. The exhaust emission standards apply starting in 2010 for new marine spark-ignition engines, including first-time EPA standards for sterndrive and inboard engines. The exhaust emission standards apply starting in 2011 and 2012 for different sizes of new land-based, spark-ignition engines at or below 19 kilowatts (kW). These small engines are used primarily in lawn and garden applications. We are also adopting evaporative emission standards for vessels and equipment using any of these engines. In addition, we are making other minor amendments to our regulations.

We estimate that by 2030, this rule will result in significantly reduced pollutant emissions from regulated engine and equipment sources, including estimated annual nationwide reductions of 604,000 tons of volatile organic hydrocarbon emissions, 132,200 tons of NO

emissions, and 5,500 tons of directly-emitted particulate matter (PM

2.5

) emissions. These reductions correspond to significant reductions in the formation of ground-level ozone. We also expect to see annual reductions of 1,461,000 tons of carbon monoxide emissions, with the greatest reductions in areas where there have been problems with individual exposures. The requirements in this rule will substantially benefit public health and welfare and the environment. We estimate that by 2030, on an annual basis, these emission reductions will prevent 230 PM-related premature deaths, between 77 and 350 ozone-related premature deaths, approximately 1,700 hospitalizations and emergency room visits, 23,000 work days lost, 180,000 lost school days, 590,000 acute respiratory symptoms, and other quantifiable benefits every year. The total annual benefits of this rule in 2030 are estimated to be between $1.8 billion and $4.4 billion, assuming a 3% discount rate. The total annual benefits of this rule in 2030 are estimated to be between $1.6 billion and $4.3 billion, assuming a 7% discount rate. Estimated costs in 2030 are many times less at approximately $190 million.

DATES:

This rule is effective on December 8, 2008. The incorporation by reference of certain publications listed in this regulation is approved by the Director of the Federal Register as of December 8, 2008.

ADDRESSES:

Docket:

All documents in the docket are listed in the

www.regulations.gov

index. Although listed in the index, some information is not publicly available, such as CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in

www.regulations.gov

or in hard copy at the “Control of Emissions from Nonroad Spark-Ignition Engines, Vessels and Equipment” Docket. The docket is located in the EPA Headquarters Library, Room Number 3334 in the EPA West Building, located at 1301 Constitution Ave., NW., Washington, DC. The EPA/DC Public Reading Room hours of operation will be 8:30 a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through Friday, excluding holidays. The telephone number for the Public Reading Room is (202) 566-1744 and the telephone number for the Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

Carol Connell, Environmental Protection Agency, Office of Transportation and Air Quality, Assessment and Standards Division, 2000 Traverwood Drive, Ann Arbor, Michigan 48105; telephone number: 734-214-4349; fax number: 734-214-4050; e-mail address:

connell.carol@epa.gov

SUPPLEMENTARY INFORMATION:

Does This Action Apply to Me?

This action will affect you if you produce or import new spark-ignition engines intended for use in marine vessels or in new vessels using such engines. This action will also affect you if you produce or import new spark-ignition engines below 19 kilowatts used in nonroad equipment, including agricultural and construction equipment, or produce or import such nonroad vehicles.

The following table gives some examples of entities that may have to follow the regulations; however, since these are only examples, you should carefully examine the regulations. Note that we are adopting minor changes in the regulations that apply to a wide range of products that may not be reflected in the following table (see Section VIII). If you have questions, call the person listed in the

FOR FURTHER INFORMATION CONTACT

section above:

Category

NAICS codes

SIC codes

Examples of potentially regulated entities

Industry

333618

3519

Manufacturers of new engines.

Industry

333111

3523

Manufacturers of farm machinery and equipment.

Industry

333112

3524

Manufacturers of lawn and garden tractors (home).

Industry

336612

3731

3732

Manufacturers of marine vessels.

Industry

811112

811198

7533

7549

Commercial importers of vehicles and vehicle components.

North American Industry Classification System (NAICS).

Standard Industrial Classification (SIC) system code.

Table of Contents

I. Introduction

A. Overview

B. Why Is EPA Taking This Action?

C. What Regulations Currently Apply to Nonroad Engines or Vehicles?

D. Putting This Rule into Perspective

E. What Requirements Are We Adopting?

F. How Is This Document Organized?

G. Judicial Review

II. Public Health and Welfare Effects

A. Public Health Impacts

B. Air Toxics

C. Carbon Monoxide

III. Sterndrive and Inboard Marine Engines

A. Overview

B. Engines Covered by This Rule

C. Exhaust Emission Standards

D. Test Procedures for Certification

E. Additional Certification and Compliance Provisions

F. Small-Business Provisions

G. Technological Feasibility

IV. Outboard and Personal Watercraft Engines

A. Overview

B. Engines Covered by This Rule

C. Final Exhaust Emission Standards

D. Changes to OB/PWC Test Procedures

E. Additional Certification and Compliance Provisions

F. Other Adjustments to Regulatory Provisions

G. Small-Business Provisions

H. Technological Feasibility

V. Small SI Engines

A. Overview

B. Engines Covered by This Rule

C. Final Requirements

D. Testing Provisions

E. Certification and Compliance Provisions for Small SI Engines and Equipment

F. Small-Business Provisions

G. Technological Feasibility

VI. Evaporative Emissions

A. Overview

B. Fuel Systems Covered by This Rule

C. Final Evaporative Emission Standards

D. Emission Credit Programs

E. Testing Requirements

F. Certification and Compliance Provisions

G. Small-Business Provisions

H. Technological Feasibility

VII. Energy, Noise, and Safety

A. Safety

B. Noise

C. Energy

VIII. Requirements Affecting Other Engine and Vehicle Categories

A. State Preemption

B. Certification Fees

C. Amendments to General Compliance Provisions in 40 CFR Part 1068

D. Amendments Related to Large SI Engines (40 CFR Part 1048)

E. Amendments Related to Recreational Vehicles (40 CFR Part 1051)

F. Amendments Related to Heavy-Duty Highway Engines (40 CFR Part 85)

G. Amendments Related to Stationary Spark-Ignition Engines (40 CFR Part 60)

H. Amendments Related to Locomotive, Marine, and Other Nonroad Compression-Ignition Engines (40 CFR Parts 89, 92, 94, 1033, 1039, and 1042)

IX. Projected Impacts

A. Emissions from Small Nonroad and Marine Spark-Ignition Engines

B. Estimated Costs

C. Cost per Ton

D. Air Quality Impact

E. Benefits

F. Economic Impact Analysis

X. Public Participation

XI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

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

H. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations.

I. Executive Order 13211: Actions that Significantly Affect Energy Supply, Distribution, or Use

J. National Technology Transfer Advancement Act

K. Congressional Review Act

I. Introduction

A. Overview

This rule will reduce the mobile-source contribution to air pollution in the United States. In particular, we are adopting standards that will require manufacturers to substantially reduce emissions from marine spark-ignition engines and from nonroad spark-ignition engines below 19 kW that are generally used in lawn and garden applications.

We refer to these as Marine SI engines and Small SI engines, respectively. The new emission standards are a continuation of the process of establishing standards for nonroad engines and vehicles as required by Clean Air Act section 213. All the nonroad engines subject to this rule are already regulated under existing emission standards, except sterndrive and inboard marine engines, which are subject to EPA emission standards for the first time.

Otto-cycle engines (referred to here as spark-ignition or SI engines) typically operate on gasoline, liquefied petroleum gas, or natural gas. Diesel-cycle engines, referred to simply as “diesel engines” in this document, may also be referred to as compression-ignition or CI engines. These engines typically operate on diesel fuel, but other fuels may also be used.

Nationwide, emissions from Marine SI engines and Small SI engines contribute significantly to mobile source air pollution. By 2030 without this final rule these engines would account for about 33 percent (1,287,000 tons) of mobile source volatile organic hydrocarbon compounds (VOC) emissions, 31 percent (15,605,000 tons) of mobile source carbon monoxide (CO) emissions, 6 percent (311,300 tons) of mobile source oxides of nitrogen (NO

) emissions, and 12 percent (44,000 tons) of mobile source particulate matter (PM

2.5

) emissions. The new standards will reduce exposure to these emissions and help avoid a range of adverse health effects associated with ambient ozone, CO, and PM levels. In addition, the new standards will help reduce acute exposure to CO, air toxics, and PM for persons who operate or who work with or are otherwise active in close proximity to these engines. They will also help address environmental problems associated with Marine SI engines and Small SI engines, such as injury to vegetation and ecosystems and visibility impairment. These effects are described in more detail later in this document.

B. Why Is EPA Taking This Action?

Clean Air Act section 213(a)(1) directs us to study emissions from nonroad engines and vehicles to determine, among other things, whether these emissions “cause, or significantly contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.” Section 213(a)(2) further requires us to determine whether emissions of CO, VOC, and NO

from all nonroad engines significantly contribute to ozone or CO concentrations in more than one nonattainment area. If we determine that emissions from all nonroad engines do contribute significantly to these nonattainment areas, section 213(a)(3) then requires us to establish emission standards for classes or categories of new nonroad engines and vehicles that cause or contribute to such pollution. We may also set emission standards under section 213(a)(4) regulating any other emissions from nonroad engines that we find contribute significantly to air pollution which may reasonably be anticipated to endanger public health or welfare.

Specific statutory direction to set standards for nonroad spark-ignition engines comes from section 428(b) of the 2004 Consolidated Appropriations Act, which requires EPA to adopt regulations under the Clean Air Act “that shall contain standards to reduce emissions from new nonroad spark-ignition engines smaller than 50 horsepower.”

As highlighted above and more fully described in Section II, these engines emit pollutants that contribute to ground-level ozone and ambient CO levels. Human exposure to ozone and CO can cause serious respiratory and cardiovascular problems. Additionally, these emissions contribute to other serious environmental degradation. This rule implements Congress' mandate by adopting new requirements for particular nonroad engines and equipment that are regulated as part of

EPA's overall nonroad emission control program.

Public Law 108-199, Div G, Title IV, § 428(b), 118 Stat. 418 (January 23, 2004).

We are adopting this rule under the procedural authority of section 307(d) of the Clean Air Act.

C. What Regulations Currently Apply to Nonroad Engines or Vehicles?

EPA has been setting emission standards for nonroad engines and/or vehicles since Congress amended the Clean Air Act in 1990 and included section 213. These amendments have led to a series of rulemakings to reduce the air pollution from this widely varying set of products. In these rulemakings, we divided the broad group of nonroad engines and vehicles into several different categories for setting application-specific requirements. Each category involves many unique characteristics related to the participating manufacturers, technology, operating characteristics, sales volumes, and market dynamics. Requirements for each category therefore take on many unique features regarding the stringency of standards, the underlying expectations regarding emission control technologies, the nature and extent of testing, and the myriad details that comprise the implementation of a compliance program.

At the same time, the requirements and other regulatory provisions for each engine category share many characteristics. Each rulemaking under section 213 sets technology-based standards consistent with the Clean Air Act and requires annual certification based on measured emission levels from test engines or vehicles. As a result, the broader context of EPA's nonroad emission control programs demonstrates both strong similarities between this rulemaking and the requirements adopted for other types of engines or vehicles and distinct differences as we take into account the unique nature of these engines and the companies that produce them.

We completed the

Nonroad Engine and Vehicle Emission Study

to satisfy Clean Air Act section 213(a)(1) in November 1991.

On June 17, 1994, we made an affirmative determination under section 213(a)(2) that nonroad emissions are significant contributors to ozone or CO in more than one nonattainment area (56 FR 31306). Since then we have undertaken several rulemakings to set emission standards for the various categories of nonroad engines. Table I-1 highlights the different engine or vehicle categories we have established and the corresponding cites for emission standards and other regulatory requirements. Table I-2 summarizes the series of EPA rulemakings that have set new or revised emission standards for any of these nonroad engines or vehicles. These actions are described in the following sections, with additional discussion to explain why we are not adopting more stringent standards for certain types of nonroad spark-ignition engines below 50 horsepower.

This study is available on EPA's Web site at

http://www.epa.gov/otaq/equip-ld

Table I-1: Nonroad Engine Categories for EPA Emission Standards

Engine categories

CFR Cite for regulations establishing emission standards

Cross

reference

to table

I-2

1. Locomotives engines

40 CFR Part 92 and 1033

d, l.

2. Marine diesel engines

40 CFR Part 94 and 1042

g, i, j, l.

3. Other nonroad diesel engines

40 CFR Parts 89 and 1039

a, e, k.

4. Marine SI engines

40 CFR Part 91

5. Recreational vehicles

40 CFR Part 1051

6. Small SI engines

40 CFR Part 90

b, f, h.

7. Large SI engines

40 CFR Part 1048

The term “Marine SI,” used throughout this document, refers to all spark-ignition engines used to propel marine vessels. This includes outboard engines, personal watercraft engines, and sterndrive/inboard engines. See Section III for additional information.

The terms “Small SI” and “Large SI” are used throughout this document. All nonroad spark-ignition engines not covered by our programs for Marine SI engines or recreational vehicles are either Small SI engines or Large SI engines. Small SI engines include those engines with maximum power at or below 19 kW, and Large SI engines include engines with maximum power above 19 kW.

Table I-2: EPA's Rulemakings for Nonroad Engines

Nonroad engines (categories and sub-categories)

Final rulemaking

Date

a. Land-based diesel engines ≥ 37 kW—Tier 1

56 FR 31306

June 17, 1994.

b. Small SI engines—Phase 1

60 FR 34581

July 3, 1995.

c. Marine SI engines—outboard and personal watercraft

61 FR 52088

October 4, 1996.

d. Locomotives

63 FR 18978

April 16, 1998.

e. Land-based diesel engines—Tier 1 and Tier 2 for engines < 37 kW—Tier 2 and Tier 3 for engines ≥ 37 kW

63 FR 56968

October 23, 1998.

f. Small SI engines (Nonhandheld)—Phase 2

64 FR 15208

March 30, 1999.

g. Commercial marine diesel < 30 liters per cylinder

64 FR 73300

December 29, 1999.

h. Small SI engines (Handheld)—Phase 2

65 FR 24268

April 25, 2000.

i. Recreational vehicles, Industrial spark-ignition engines > 19 kW, and Recreational marine diesel

67 FR 68242

November 8, 2002.

j. Marine diesel engines ≥ 2.5 liters/cylinder

68 FR 9746

February 28, 2003.

k. Land-based diesel engines—Tier 4

69 FR 38958

June 29, 2004.

l. Locomotives and commercial marine diesel < 30 liters per cylinder

73 FR 37096

June 30, 2008.

Small SI Engines

We have previously adopted emission standards for nonroad spark-ignition engines at or below 19 kW in two phases. The first phase of these standards introduced certification and an initial level of emission standards for both handheld and nonhandheld engines. On March 30, 1999 we adopted a second phase of standards for nonhandheld engines, including both Class I and Class II engines (64 FR 15208).

The Phase 2 regulations included a phase-in period that has recently been completed. These standards involved emission reductions based on improving engine calibrations to reduce exhaust emissions and added a requirement that emission standards must be met over the engines' entire useful life as defined in the regulations. We believe catalyst technology has now developed to the point that it can be applied to all nonhandheld Small SI engines to reduce exhaust emissions. Various emission control technologies are similarly available to address the different types of fuel evaporative emissions we have identified.

Handheld engines generally include those engines for which the operator holds or supports the equipment during operation; nonhandheld engines are Small SI engines that are not handheld engines (see § 1054.801). Class I refers to nonhandheld engines with displacement below 225 cc; Class II refers to larger nonhandheld engines.

For handheld engines, we adopted Phase 2 exhaust emission standards in April 25, 2000 (65 FR 24268). These standards were based on the application of catalyst technology, with the expectation that manufacturers would have to make considerable investments to modify their engine designs and production processes. A technology review we completed in 2003 indicated that manufacturers were making progress toward compliance, but that additional implementation flexibility was needed if manufacturers were to fully comply with the regulations by 2010. This finding and a change in the rule were published in the

Federal Register

on January 12, 2004 (69 FR 1824). At this point, we have no information to suggest that manufacturers can uniformly apply new technology or make design improvements to reduce exhaust emissions below the Phase 2 levels. We therefore believe the Phase 2 standards continue to represent the greatest degree of emission reduction achievable for these engines.

However, we believe it is appropriate to apply evaporative emission standards to handheld engines similar to the standards we are adopting for the nonhandheld engines. Manufacturers can control evaporative emissions from handheld engines in a way that has little or no impact on exhaust emissions.

Note that we refer to the handheld exhaust emission standards in 40 CFR part 1054 as Phase 3 standards. This is intended to maintain consistent terminology with the comparable standards in California rather than indicating an increase in stringency.

Marine SI Engines

On October 4, 1996 we adopted emission standards for spark-ignition outboard and personal watercraft engines that have recently been fully phased in (61 FR 52088). We decided not to finalize emission standards for sterndrive or inboard marine engines at that time. Uncontrolled emission levels from sterndrive and inboard marine engines were already significantly lower than the outboard and personal watercraft engines. We did, however, leave open the possibility of revisiting the need for emission standards for sterndrive and inboard engines in the future. See Section III for further discussion of the scope and background of past and current rulemakings for these engines.

We believe existing technology can be applied to all Marine SI engines to reduce emissions of harmful pollutants, including both exhaust and evaporative emissions. Manufacturers of outboard and personal watercraft engines can continue the trend of producing four-stroke engines and advanced-technology two-stroke engines to further reduce emissions. For sterndrive/inboard engines, manufacturers can add technologies, such as fuel injection and aftertreatment, that can safely and substantially improve the engines' emission control capabilities.

Large SI Engines

We adopted emission standards for Large SI engines on November 8, 2002 (67 FR 68242). This includes Tier 1 standards for 2004 through 2006 model years and Tier 2 standards starting with 2007 model year engines. Manufacturers are today facing a considerable challenge to comply with the Tier 2 standards, which are already substantially more stringent than any of the standards for the other engine categories subject to this final rule. The Tier 2 standards also include evaporative emission standards, new transient test procedures, additional exhaust emission standards to address off-cycle emissions, and diagnostic requirements. Stringent standards for this category of engines, and in particular engines between 25 and 50 horsepower (19 to 37 kW), have been completed in the recent past, and are currently being implemented. We do not have information at this time on possible advances in technology beyond Tier 2. We therefore believe the evidence provided in the recently promulgated rulemaking continues to represent the best available information regarding the appropriate level of standards for these engines under section 213 at this time. The California Air Resources Board has adopted an additional level of emission control for Large SI engines starting with the 2010 model year. However, as described in Section I.D.1, their new standards do not increase overall stringency beyond that reflected in the federal standards. As a result, we believe it is inappropriate to adopt more stringent emission standards for these engines in this rulemaking.

Note that the Large SI standards apply to nonroad spark-ignition engines above 19 kW. However, we adopted a special provision for engine families where production engines have total displacement at or below 1000 cc and maximum power at or below 30 kW, allowing these engine families to instead certify to the applicable standards for Small SI engines. This rule preserves this approach.

Recreational Vehicles

We adopted exhaust and evaporative emission standards for recreational vehicles in our November 8, 2002 final rule (67 FR 68242). These standards apply to all-terrain vehicles, off-highway motorcycles, and snowmobiles.

These exhaust emission standards were fully phased in starting with the 2007 model year. The evaporative emission standards apply starting with the 2008 model year.

Note that we treat certain high-speed off-road utility vehicles as all-terrain vehicles (see 40 CFR part 1051).

Recreational vehicles will soon be subject to permeation requirements that are very similar to the requirements included in this rulemaking. We have also learned more about controlling running losses and diffusion emissions that may eventually lead us to propose comparable standards for recreational vehicles. Considering these new requirements for recreational vehicles in a later rulemaking would give us additional time to collect information to better understand the feasibility, costs, and benefits of applying these requirements to recreational vehicles.

The following sections describe the state of technology and regulatory requirements for the different types of recreational vehicles.

All-Terrain Vehicles

EPA's initial round of exhaust emission standards was fully implemented starting with the 2007 model year. The regulations for all-terrain vehicles (ATV) specify testing based on a chassis-based transient procedure. However, we permit manufacturers on an interim basis to optionally use a steady-state engine-based procedure. We recently completed a change in the regulations to extend this allowance from 2009 through 2014, after which manufacturers must certify all their ATVs based on the chassis-based transient test procedure that applies for off-highway motorcycles (72 FR 20730, April 26, 2007). This change does not represent an increase in stringency, but manufacturers will be taking time to make the transition to the different test procedure. We expect that there will be a good potential to apply further emission controls on these engines. However, we do not have information at this time on possible advances in technology beyond what is required for the current standards.

Off-Highway Motorcycles

For off-highway motorcycles, manufacturers are in many cases making a substantial transition to move away from two-stroke engines in favor of four-stroke engines. This transition is now underway. While it may eventually be appropriate to apply aftertreatment or other additional emission control technologies to off-highway motorcycles, we need more time for this transition to be completed and to assess the success of aftertreatment technologies such as catalysts on similar applications such as highway motorcycles. As EPA and manufacturers learn more in implementing emission standards, we expect to be able to better judge the potential for broadly applying new technology to achieve further emission reductions from off-highway motorcycles.

Snowmobiles

In our November 8, 2002 final rule we set three phases of exhaust emission standards for snowmobiles (67 FR 68242). Environmental and industry groups challenged the third phase of these standards. The court decision upheld much of EPA's reasoning for the standards, but vacated the NO

standard and remanded the CO and HC standards to clarify the analysis and evidence upon which the standards are based. See

Bluewater Network, et al.

EPA, 370 F 3d 1

(D.C. Cir. 2004). A large majority of snowmobile engines are rated above 50 hp and there is still a fundamental need for time to pass to allow us to assess the success of four-stroke engine technology in the marketplace.

This is an important aspect of the assessment we need to conduct with regard to the Phase 3 emission standards. We believe it is best to address this in a separate rulemaking and we have initiated that effort to evaluate the appropriate long-term emission standards for snowmobiles.

Only about 3 percent of snowmobiles are rated below 50 horsepower.

Nonroad Diesel Engines

The 2004 Consolidated Appropriations Act providing the specific statutory direction for this rulemaking focuses on nonroad spark-ignition engines. Nonroad diesel engines are therefore not included within the scope of that Congressional mandate. However, we have gone through several rulemakings to set standards for these engines under the broader authority of Clean Air Act section 213. In particular, we have divided nonroad diesel engines into three groups for setting emission standards. We adopted a series of standards for locomotives on April 16, 1998, including requirements to certify engines to emission standards when they are rebuilt (63 FR 18978). We also adopted emission standards for marine diesel engines over several different rulemakings, as described in Table I-2. These included separate actions for engines below 37 kW, engines installed in oceangoing vessels, engines installed in commercial vessels involved in inland and coastal waterways, and engines installed in recreational vessels. We recently adopted a new round of more stringent emission standards for both locomotives and marine diesel engines that will require widespread use of aftertreatment technology (73 FR 37096, June 30, 2008).

Finally, all other nonroad diesel engines are grouped together for EPA's emission standards. We have adopted multiple tiers of increasingly stringent standards in three separate rulemakings, as described in Table I-2. We most recently adopted Tier 4 standards based on the use of ultra low-sulfur diesel fuel and the application of exhaust aftertreatment technology (69 FR 38958, June 29, 2004).

D. Putting This Rule into Perspective

Most manufacturers that will be subject to this rulemaking are also affected by regulatory developments in California and in other countries. Each of these is described in more detail below.

State Initiatives

Clean Air Act section 209 prohibits California and other states from setting emission standards for new motor vehicles and new motor vehicle engines, but authorizes EPA to waive this prohibition for California, in which case other states may adopt California's standards. Similar preemption and waiver provisions apply for emission standards for nonroad engines and vehicles, whether new or in-use. However for new locomotives, new engines used in locomotives, and new engines used in farm or construction equipment with maximum power below 130 kW, California and other states are preempted and there is no provision for a waiver of preemption. In addition, in section 428 of the 2004 Consolidated Appropriations Act, Congress further precluded other states from adopting new California standards for nonroad spark-ignition engines below 50 horsepower. In addition, the amendment required that we specifically address the safety implications of any California standards for these engines before approving a waiver of federal preemption. We are codifying these preemption changes in this rule.

The California Air Resources Board (California ARB) has adopted requirements for five groups of nonroad engines: (1) Diesel- and Otto-cycle small off-road engines rated under 19 kW; (2) spark-ignition engines used for marine propulsion; (3) land-based nonroad recreational engines, including those used in all-terrain vehicles, off-highway motorcycles, go-carts, and other similar vehicles; (4) new nonroad spark-ignition engines rated over 19 kW not used in recreational applications; and (5) new land-based nonroad diesel engines rated over 130 kW. They have also approved a voluntary registration and control program for existing portable equipment.

In the 1990s California ARB adopted Tier 1 and Tier 2 standards for Small SI engines consistent with the federal requirements. In 2003, they moved beyond the federal program by adopting exhaust HC+NO

emission standards of 10 g/kW-hr for Class I engines starting in the 2007 model year and 8 g/kW-hr for Class II engines starting in the 2008 model year. In the same rule they adopted evaporative emission standards for nonhandheld equipment, requiring control of fuel tank permeation, fuel line permeation, diurnal emissions, and running losses.

California ARB has adopted two tiers of exhaust emission standards for outboard and personal watercraft engines beyond EPA's original standards. The most recent standards, which apply starting in 2008, require HC+NO

emission levels as low as 16 g/kW-hr. For sterndrive and inboard engines, California ARB has adopted a 5 g/kW-hr HC+NO

emission standard for 2008 and later model year engines, with testing underway to confirm the feasibility of standards. California ARB's marine programs include no standards for exhaust CO emissions or evaporative emissions.

The California ARB emission standards for recreational vehicles have a different form than the comparable EPA standards but are roughly equivalent in stringency. The California standards include no standards for controlling evaporative emissions. Another important difference between the two programs is California ARB's reliance on a provision allowing noncompliant vehicles to be used in certain areas that are less environmentally sensitive as long as they have a specified red sticker for identifying their lack of emission controls to prevent them from operating in other areas.

California ARB in 1998 adopted requirements that apply to new nonroad engines rated over 25 hp produced for California, with standards phasing in from 2001 through 2004. Texas has adopted these initial California ARB emission standards statewide starting in 2004. More recently, California ARB adopted exhaust emission standards and new evaporative emission standards for these engines, consistent with EPA's 2007 model year standards. Their new requirements also included an additional level of emission control for Large SI engines starting with the 2010 model year. However, their 2010 standards do not increase overall stringency beyond that reflected in the federal standards. Rather, they aim to achieve reductions in HC+NO

emissions by removing the flexibility incorporated into the federal standards allowing manufacturers to have higher HC+NO

emissions by certifying to a more stringent CO standard.

Actions in Other Countries

While the new emission standards will apply only to engines sold in the United States, we are aware that manufacturers in many cases are selling the same products into other countries. To the extent that we have the same emission standards as other countries, manufacturers can contribute to reducing air emissions without being burdened by the costs associated with meeting differing or inconsistent regulatory requirements. The following discussion describes our understanding of the status of emission standards in countries outside the United States.

Regulations for spark ignition engines in handheld and nonhandheld equipment are included in the “Directive 97/68/EC of the European Parliament and of the Council of 16 December 1997 on the approximation of the laws of the Member States relating to measures against the emission of gaseous and particulate pollutants from internal combustion engines to be installed in non-road mobile machinery (OJ L 59, 27.2.1998, p. 1)”, as amended by “Directive 2002/88/EC of the European Parliament and of the Council of 9 December 2002.” The Stage I emission standards are to be met by all handheld and nonhandheld engines by 24 months after entry into force of the Directive (as noted in a December 9, 2002 amendment to Directive 97/68/EC). The Stage I emission standards are similar to the U.S. EPA's Phase 1 emission standards for handheld and nonhandheld engines. The Stage II emission standards are implemented over time for the various handheld and nonhandheld engine classes from 2005 to 2009 with handheld engines at or above 50 cc on August 1, 2008. The Stage II emission standards are similar to EPA's Phase 2 emission standards for handheld and nonhandheld engines. Six months after these dates Member States must require that engines placed on the market meet the requirements of the Directive, whether or not they are already installed in machinery.

The European Commission has adopted emission standards for recreational marine engines, including both diesel and gasoline engines. These requirements apply to all new engines sold in member countries and began in 2006 for four-stroke engines and in 2007 for two-stroke engines. Table I-3 presents the European standards for diesel and gasoline recreational marine engines. The numerical emission standards for NO

are based on the applicable standard from MARPOL Annex VI for marine diesel engines (See Table I-3). The European standards are roughly equivalent to the nonroad diesel Tier 1 emission standards for HC and CO. Emission measurements under the European standards rely on the ISO D2 duty cycle for constant-speed engines and the ISO E5 duty cycle for other engines.

Table I-3: European Emission Standards for Recreational Marine Engines (

g/k

W-

hr)

Engine type

Two-Stroke Spark-Ignition

30 + 100/P

0.75

10.0

150 + 600/P

—

Four-Stroke Spark-Ignition

6 + 50/P

0.75

15.0

150 + 600/P

—

Compression-Ignition

1.5 + 2/P

0.5

9.8

5.0

1.0

Note: P = rated power in kilowatts (kW).

E. What Requirements Are We Adopting?

EPA's emission control provisions require engine, vessel and equipment manufacturers to design and produce their products to meet the emission standards we adopt. To ensure that engines and fuel systems meet the expected level of emission control, we also require compliance with a variety of additional requirements, such as certification, labeling engines, and meeting warranty requirements. The following sections provide a brief summary of the new requirements in this rulemaking. See the later sections for a full discussion of the rule.

Marine SI Engines and Vessels

We are adopting a more stringent level of emission standards for outboard and personal watercraft engines starting with the 2010 model year. The HC+NO

emission standards are the same as those adopted by California ARB for 2008 and later model year engines. The CO emission standard is 300 g/kW-hr for engines with maximum engine power above 40 kW; the standard increases as a function of maximum engine power for smaller engines. We expect manufacturers to meet these standards with improved fueling systems and other in-cylinder controls. We are not pursuing catalyst-based emission standards for outboard and personal watercraft engines. As discussed below, the application of

catalyst-based standards to the marine environment creates special technology challenges that must be addressed. Unlike the sterndrive/inboard engines discussed in the next paragraph, outboard and personal watercraft engines are not built from automotive engine blocks and it is not straightforward to apply the fundamental engine modifications, fuel system upgrades, and other engine control modifications needed to get acceptable catalyst performance. This rule is an appropriate next step in the evolution of technology-based standards for outboard and personal watercraft engines as they are likely to lead to the elimination of carbureted two-stroke engines in favor of four-stroke engines or direct-injection two-stroke engines and to encourage the fuel system upgrades and related engine modifications needed to achieve the required reductions and to potentially set the stage for more stringent controls in the future.

We are adopting new exhaust emission standards for sterndrive and inboard marine engines. The standards are 5.0 g/kW-hr for HC+NO

and 75.0 g/kW-hr for CO starting with the 2010 model year. We expect manufacturers to meet these standards with three-way catalysts and closed-loop fuel injection. To ensure proper functioning of these emission control systems in use, we will require engines to have a diagnostic system for detecting a failure in the emission control system. For sterndrive and inboard marine engines above 373 kW with high-performance characteristics (generally referred to as “SD/I high-performance engines”), we are adopting less stringent emission standards that reflect their limited ability to control emissions with catalysts. The HC+NO

standard is 16 g/kW-hr in for engines at or below 485 kW and 22 g/kW-hr for bigger engines. The CO standard for all SD/I high-performance engines is 350 g/kW-hr. Manufacturers of these engines must meet emission standards without generating or using emission credits. We also include a variety of other special provisions for these engines to reflect unique operating characteristics.

The emission standards described above relate to engine operation over a prescribed duty cycle for testing in the laboratory. We are also adopting not-to-exceed (NTE) standards that establish emission limits when engines operate under normal speed-load combinations that are not included in the duty cycles for the other engine standards (the NTE standards do not apply to SD/I high-performance engines).

We are adopting new standards to control evaporative emissions for all Marine SI vessels. The new standards include requirements to control fuel tank permeation, fuel line permeation, and diurnal emissions, including provisions to ensure that refueling emissions do not increase.

We are including these new regulations for Marine SI engines in 40 CFR part 1045 rather than in the current regulations in 40 CFR part 91. This new part allows us to improve the clarity of regulatory requirements and update our regulatory compliance program to be consistent with the provisions we have recently adopted for other nonroad programs. We are also making a variety of changes to 40 CFR part 91 to make minor adjustments to the current regulations and to prepare for the transition to 40 CFR part 1045.

Small SI Engines and Equipment

We are adopting HC+NO

exhaust emission standards of 10.0 g/kW-hr for Class I engines starting in the 2012 model year and 8.0 g/kW-hr for Class II engines starting in the 2011 model year. For both classes of nonhandheld engines, we are maintaining the existing CO standard of 610 g/kW-hr. We expect manufacturers to meet these standards by improving engine combustion and adding catalysts. These standards are consistent with the requirements recently adopted by California ARB.

For spark-ignition engines used in marine generators, we are adopting a more stringent Phase 3 CO emission standard of 5.0 g/kW-hr. This applies equally to all sizes of engines subject to the Small SI standards.

We are adopting new evaporative emission standards for both handheld and nonhandheld engines. The new standards include requirements to control permeation from fuel tanks and fuel lines. For nonhandheld engines we will also require control of running loss emissions.

We are drafting the new regulations for Small SI engines from 40 CFR part 90 rather than changing the current regulations in 40 CFR part 90. This new part will allow us to improve the clarity of regulatory requirements and update our regulatory compliance program to be consistent with the provisions we have recently adopted for other nonroad programs.

F. How Is This Document Organized?

Many readers may be interested only in certain aspects of the rule since it covers a broad range of engines and equipment that vary in design and use. We have therefore attempted to organize this information in a way that allows each reader to focus on the material of particular interest. The Air Quality discussion in Section II, however, is general in nature and applies to all the categories subject to the rule.

The next several sections describe the provisions that apply for Small SI engines and equipment and Marine SI engines and vessels. Sections III through V describe the new requirements related to exhaust emission standards for each of the affected engine categories, including standards, effective dates, testing information, and other specific requirements. Section VI details the new requirements related to evaporative emissions for all categories. Section VII discusses how we took energy, noise, and safety factors into consideration for the new standards.

Section VIII describes a variety of provisions that affect other categories of engines besides those that are the primary subject of this rule. This includes the following changes:

• We are reorganizing the regulatory language related to preemption of state standards and to clarify certain provisions.

• We are incorporating new provisions related to certification fees for newly regulated products covered by this rule. This involves some restructuring of the regulatory language. We are also adopting various technical amendments, such as identifying an additional payment method, that apply broadly to our certification programs.

• We are modifying 40 CFR part 1068 to clarify when engines are subject to standards. This includes several new provisions to address special cases for partially complete engines.

• We are also modifying part 1068 to clarify how the provisions apply with respect to evaporative emission standards and we are adopting various technical amendments. These changes apply to all types of nonroad engines that are subject to the provisions of part 1068.

• We are adopting several technical amendments for other categories of nonroad engines and vehicles, largely to maintain consistency across programs for different categories of engines and vehicles.

• We are amending provisions related to delegated assembly. The new approach is to adopt a universal set of requirements in § 1068.261 that applies uniformly to heavy-duty highway engines and nonroad engines.

• We are clarifying that the new exhaust and evaporative emission standards for Small SI engines also apply to the comparable stationary engines.

Section IX summarizes the projected impacts and benefits of this rule. Finally, Sections X and XI summarize the primary public comments received and describe how we satisfy our various administrative requirements.

G. Judicial Review

Under section 307(b)(1) of the Clean Air Act (CAA), judicial review of these final rules is available only by filing a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit by December 8, 2008. Under section 307(b)(2) of the CAA, the requirements established by these final rules may not be challenged separately in any civil or criminal proceedings brought by EPA to enforce these requirements.

Section 307(d)(7)(B) of the CAA further provides that “[o]nly an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment (including any public hearing) may be raised during judicial review.” This section also provides a mechanism for us to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to the EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” Any person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 20460, with a copy to both the person(s) listed in the preceding

FOR FURTHER INFORMATION CONTACT

section and the Associate General Counsel for the Air and Radiation Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave., NW., Washington, DC 20460.

II. Public Health and Welfare Effects

The engines and fuel systems subject to this rule generate emissions of hydrocarbons (HC), nitrogen oxides (NO

), particulate matter (PM) and carbon monoxide (CO) that contribute to nonattainment of the National Ambient Air Quality Standards (NAAQS) for ozone, PM and CO. These engines and fuel systems also emit hazardous air pollutants (air toxics) that are associated with a host of adverse health effects. Emissions from these engines and fuel systems also contribute to visibility impairment and other welfare and environmental effects.

This section summarizes the general health and welfare effects of these emissions. Interested readers are encouraged to refer to the Final RIA for more in-depth discussions.

A. Public Health Impacts

Ozone

The Small SI engine and Marine SI engine standards finalized in this action will result in reductions of volatile organic compounds (VOC), of which HC are a subset, and NO

emissions. VOC and NO

contribute to the formation of ground-level ozone pollution or smog. People in many areas across the U.S. continue to be exposed to unhealthy levels of ambient ozone.

Background

Ground-level ozone pollution is typically formed by the reaction of VOC and NO

in the lower atmosphere in the presence of heat and sunlight. These pollutants, often referred to as ozone precursors, are emitted by many types of pollution sources, such as highway and nonroad motor vehicles and engines, power plants, chemical plants, refineries, makers of consumer and commercial products, industrial facilities, and smaller area sources.

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

Ground-level ozone is produced and destroyed in a cyclical set of chemical reactions, many of which are sensitive to temperature and sunlight. When ambient temperatures and sunlight levels remain high for several days and the air is relatively stagnant, ozone and its precursors can build up and result in more ozone than typically occurs on a single high-temperature day. Ozone can be transported hundreds of miles downwind of precursor emissions, resulting in elevated ozone levels even in areas with low local VOC or NO

emissions.

U.S. EPA Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental Protection Agency, Washington, D.C., EPA 600/R-05/004aF-cF, 2006. This document is available in Docket EPA-HQ-OAR-2003-0190. This document may be accessed electronically at:

http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html

EPA has recently amended the ozone NAAQS (73 FR 16436, March 27, 2008). The final ozone NAAQS rule addresses revisions to the primary and secondary NAAQS for ozone to provide increased protection of public health and welfare, respectively. With regard to the primary standard for ozone, EPA has revised the level of the 8-hour standard to 0.075 parts per million (ppm), expressed to three decimal places. With regard to the secondary standard for ozone, EPA has revised the current 8-hour standard by making it identical to the revised primary standard.

Health Effects of Ozone

The health and welfare effects of ozone are well documented and are assessed in EPA's 2006 ozone Air Quality Criteria Document (ozone AQCD) and EPA Staff Paper.

9, 10

Ozone can irritate the respiratory system, causing coughing, throat irritation, and/or uncomfortable sensation in the chest. Ozone can reduce lung function and make it more difficult to breathe deeply; breathing may also become more rapid and shallow than normal, thereby limiting a person's activity. Ozone can also aggravate asthma, leading to more asthma attacks that require medical attention and/or the use of additional medication. In addition, there is suggestive evidence of a contribution of ozone to cardiovascular-related morbidity and highly suggestive evidence that short-term ozone exposure directly or indirectly contributes to non-accidental and cardiopulmonary-related mortality, but additional research is needed to clarify the underlying mechanisms causing these effects. In a recent report on the estimation of ozone-related premature mortality published by the National Research Council (NRC), a panel of experts and reviewers concluded that short-term exposure to ambient ozone is likely to contribute to premature deaths and that ozone-related mortality should be included in estimates of the health benefits of reducing ozone exposure.

Animal toxicological evidence indicates that with repeated exposure, ozone can inflame and damage the lining of the lungs, which may lead to permanent changes in lung tissue and irreversible reductions in lung function. People who are more susceptible to effects

associated with exposure to ozone can include children, the elderly, and individuals with respiratory disease such as asthma. Those with greater exposures to ozone, for instance due to time spent outdoors (e.g., children and outdoor workers), are also of particular concern.

U.S. EPA Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental Protection Agency, Washington, DC., EPA 600/R-05/004aF-cF, 2006. This document is available in Docket EPA-HQ-OAR-2003-0190. This document may be accessed electronically at:

http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html

U.S. EPA (2007) Review of the National Ambient Air Quality Standards for Ozone, Policy Assessment of Scientific and Technical Information. OAQPS Staff Paper.EPA-452/R-07-003. This document is available in Docket EPA-HQ-OAR-2003-0190. This document is available electronically at:

http:www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_sp.html

National Research Council (NRC), 2008. Estimating Mortality Risk Reduction and Economic Benefits from Controlling Ozone Air Pollution. The National Academies Press: Washington, DC.

The recent ozone AQCD also examined relevant new scientific information that has emerged in the past decade, including the impact of ozone exposure on such health effects as changes in lung structure and biochemistry, inflammation of the lungs, exacerbation and causation of asthma, respiratory illness-related school absence, hospital admissions and premature mortality. Animal toxicological studies have suggested potential interactions between ozone and PM with increased responses observed to mixtures of the two pollutants compared to either ozone or PM alone. The respiratory morbidity observed in animal studies along with the evidence from epidemiologic studies supports a causal relationship between acute ambient ozone exposures and increased respiratory-related emergency room visits and hospitalizations in the warm season. In addition, there is suggestive evidence of a contribution of ozone to cardiovascular-related morbidity and non-accidental and cardiopulmonary mortality.

Plant and Ecosystem Effects of Ozone

Elevated ozone levels contribute to environmental effects, with impacts to plants and ecosystems being of most concern. Ozone can produce both acute and chronic injury in sensitive species depending on the concentration level and the duration of the exposure. Ozone effects also tend to accumulate over the growing season of the plant, so that even low concentrations experienced for a longer duration have the potential to create chronic stress on vegetation. Ozone damage to plants includes visible injury to leaves and a reduction in food production through impaired photosynthesis, both of which can lead to reduced crop yields, forestry production, and use of sensitive ornamentals in landscaping. In addition, the reduced food production in plants and subsequent reduced root growth and storage below ground, can result in other, more subtle plant and ecosystems impacts. These include increased susceptibility of plants to insect attack, disease, harsh weather, interspecies competition and overall decreased plant vigor. The adverse effects of ozone on forest and other natural vegetation can potentially lead to species shifts and loss from the affected ecosystems, resulting in a loss or reduction in associated ecosystem goods and services. Lastly, visible ozone injury to leaves can result in a loss of aesthetic value in areas of special scenic significance like national parks and wilderness areas. The final 2006 Criteria Document presents more detailed information on ozone effects on vegetation and ecosystems.

Current and Projected Ozone Levels

Ozone concentrations exceeding the level of the 1997 8-hour ozone NAAQS occur over wide geographic areas, including most of the nation's major population centers.

As of March 12, 2008, there were approximately 140 million people living in 72 areas (which include all or part of 337 counties) designated as not in attainment with the 1997 8-hour ozone NAAQS.

These numbers do not include the people living in areas where there is a future risk of failing to maintain or attain the 8-hour ozone NAAQS. The 1997 ozone NAAQS was recently revised and the 2008 ozone NAAQS was final on March 12, 2008. Table II-1 presents the number of counties in areas currently designated as nonattainment for the 1997 ozone NAAQS as well as the number of additional counties that have design values greater than the 2008 ozone NAAQS.

A listing of the 8-hour ozone nonattainment areas is included in the RIA for this rule.

Population numbers are from 2000 census data.

Table II-1—Counties With Design Values Greater Than the 2008 Ozone NAAQS Based on 2004-2006 Air Quality Data

Number of

Counties

Population

1997 Ozone Standard: Counties within the 72 areas currently designated as nonattainment

337

139,633,458

2008 Ozone Standard: Additional counties that would not meet the 2008 NAAQS

15,984,135

Total

411

155,617,593

Notes:

Population numbers are from 2000 census data.

Attainment designations for 2008 ozone NAAQS have not yet been made. Nonattainment for the 2008 Ozone NAAQS will be based on three years of air quality data from later years. Also, the county numbers in the table include only the counties with monitors violating the 2008 Ozone NAAQS. The numbers in this table may be an underestimate of the number of counties and populations that will eventually be included in areas with multiple counties designated nonattainment.

States with 8-hour ozone nonattainment areas are required to take action to bring those areas into compliance in the future. Based on the final rule designating and classifying 8-hour ozone nonattainment areas (69 FR 23951, April 30, 2004), most 8-hour ozone nonattainment areas will be required to attain the 1997 ozone NAAQS in the 2007 to 2013 time frame and then maintain the NAAQS thereafter.

Many of these nonattainment areas will need to adopt additional emission reduction programs and the VOC and NO

reductions from this final action are particularly important for these states. The attainment dates associated with the potential new 2008 ozone nonattainment areas are likely to be in the 2013 to 2021 timeframe, depending on the severity of the problem.

The Los Angeles South Coast Air Basin 8-hour ozone nonattainment area will have to attain before June 15, 2021.

EPA has already adopted many emission control programs that are expected to reduce ambient ozone levels. Some of these control programs are described in Section I.C.1. As a result of existing programs, the number of areas that fail to meet the ozone NAAQS in the future is expected to decrease. Based on the air quality modeling performed for this rule, which does not include any additional local controls, we estimate eight counties (where 22 million people are projected to live) will exceed the 1997 8-hour

ozone NAAQS in 2020.

An additional 37 counties (where 27 million people are projected to live) are expected to be within 10 percent of violating the 1997 8-hour ozone NAAQS in 2020.

We expect many of the 8-hour ozone nonattainment areas to adopt additional emission reduction programs but we are unable to quantify or rely upon future reductions from additional state and local programs that have not yet been adopted.

Results from the air quality modeling conducted for this final rule indicate that the Small SI and Marine SI engine emission reductions in 2020 and 2030 will improve both the average and population-weighted average ozone concentrations for the U.S. In addition, the air quality modeling shows that on average this final rule will help bring counties closer to ozone attainment as well as assist counties whose ozone concentrations are within ten percent below the standard. For example, on a population-weighted basis, the average modeled future-year 8-hour ozone design values will decrease by 0.57 ppb in 2020 and 0.76 ppb in 2030.

The air quality modeling methodology and the projected reductions are discussed in more detail in Chapter 2 of the RIA.

Ozone design values are reported in parts per million (ppm) as specified in 40 CFR Part 50. Due to the scale of the design value changes in this action, results have been presented in parts per billion (ppb) format.

Particulate Matter

The Small SI engine and Marine SI engine standards detailed in this action will result in reductions in emissions of VOCs and NO

which contribute to the formation of secondary PM

2.5

. In addition, the standards finalized today will reduce primary (directly emitted) PM

2.5

emissions.

Background

PM represents a broad class of chemically and physically diverse substances. It can be principally characterized as discrete particles that exist in the condensed (liquid or solid) phase spanning several orders of magnitude in size. PM is further described by breaking it down into size fractions. PM

refers to particles generally less than or equal to 10 micrometers (m) in aerodynamic diameter. PM

2.5

refers to fine particles, generally less than or equal to 2.5 in aerodynamic diameter. Inhalable (or “thoracic”) coarse particles refer to those particles generally greater than 2.5 μm but less than or equal to 10 μm in aerodynamic diameter. Ultrafine PM refers to particles less than 100 nanometers (0.1 μm) in aerodynamic diameter. Larger particles tend to be removed by the respiratory clearance mechanisms (

e.g.

coughing), whereas smaller particles are deposited deeper in the lungs.

Fine particles are produced primarily by combustion processes and by transformations of gaseous emissions (e.g., SO

, NO

and VOC) in the atmosphere. The chemical and physical properties of PM

2.5

may vary greatly with time, region, meteorology, and source category. Thus, PM

2.5

may include a complex mixture of different pollutants including sulfates, nitrates, organic compounds, elemental carbon and metal compounds. These particles can remain in the atmosphere for days to weeks and travel hundreds to thousands of kilometers.

The primary PM

2.5

NAAQS includes a short-term (24-hour) and a long-term (annual) standard. The 1997 PM

2.5

NAAQS established by EPA set the 24-hour standard at a level of 65μg/m

based on the 98th percentile concentration averaged over three years. The annual standard specifies an expected annual arithmetic mean not to exceed 15μg/m

averaged over three years.

In 2006, EPA amended the NAAQS for PM

2.5

(71 FR 61144, October 17, 2006). The final rule addressed revisions to the primary and secondary NAAQS for PM to provide increased protection of public health and welfare, respectively. The level of the 24-hour PM

2.5

NAAQS was revised from 65μg/m

to 35 μg/m

and the level of the annual PM

2.5

NAAQS was retained at 15μg/m

. With regard to the secondary standards for PM

2.5

, EPA has revised these standards to be identical in all respects to the revised primary standards.

Health Effects of PM

2.5

Scientific studies show ambient PM is associated with a series of adverse health effects. These health effects are discussed in detail in the 2004 EPA Particulate Matter Air Quality Criteria Document (PM AQCD), and the 2005 PM Staff Paper.

17 18

Further discussion of health effects associated with PM can also be found in the RIA for this rule.

U.S. EPA (2004) Air Quality Criteria for Particulate Matter (Oct 2004), Volume I Document No. EPA600/P-99/002aF and Volume II Document No. EPA600/P-99/002bF. This document is available in Docket EPA-HQ-OAR-2003-0190.

U.S. EPA (2005) Review of the National Ambient Air Quality Standard for Particulate Matter: Policy Assessment of Scientific and Technical Information, OAQPS Staff Paper. EPA-452/R-05-005. This document is available in Docket EPA-HQ-OAR-2003-0190.

Health effects associated with short-term exposures (hours to days) to ambient PM include premature mortality, increased hospital admissions, heart and lung diseases, increased cough, adverse lower-respiratory symptoms, decrements in lung function and changes in heart rate rhythm and other cardiac effects. Studies examining populations exposed to different levels of air pollution over a number of years, including the Harvard Six Cities Study and the American Cancer Society Study, show associations between long-term exposure to ambient PM

2.5

and both total and cardiovascular and respiratory mortality.

In addition, a reanalysis of the American Cancer Society Study shows an association between fine particle and sulfate concentrations and lung cancer mortality.

Dockery, DW; Pope, CA III: Xu, X;

et al.

1993. An association between air pollution and mortality in six U.S. cities. N Engl J Med 329:1753-1759.

Pope, C. A., III; Burnett, R. T.; Thun, M. J.; Calle, E. E.; Krewski, D.; Ito, K.; Thurston, G. D. (2002) Lung cancer, cardiopulmonary mortality, and long-term exposure to fine particulate air pollution. J. Am. Med. Assoc. 287:1132-1141.

Recently, several studies have highlighted the adverse effects of PM specifically from mobile sources.

21 22

Studies have also focused on health effects due to PM exposures on or near roadways.

Although these studies include all air pollution sources, including both spark-ignition (gasoline) and diesel powered vehicles, they indicate that exposure to PM emissions near roadways, thus dominated by mobile sources, are associated with health effects. The controls finalized in this action may help to reduce exposures, and specifically exposures near the source, to mobile source related PM

2.5

Laden, F.; Neas, L.M.; Dockery, D.W.; Schwartz, J. (2000) Association of Fine Particulate Matter from Different Sources with Daily Mortality in Six U.S. Cities.

Environmental Health Perspectives

108: 941-947.

Janssen, N.A.H.; Schwartz, J.; Zanobetti, A.; Suh, H.H. (2002) Air Conditioning and Source-Specific Particles as Modifiers of the Effect of PM

on Hospital Admissions for Heart and Lung Disease.

Environmental Health Perspectives

110: 43-49.

Riediker, M.; Cascio, W.E.; Griggs, T.R..; Herbst, M.C.; Bromberg, P.A.; Neas, L.; Williams, R.W.; Devlin, R.B. (2003) Particulate Matter Exposures in Cars is Associated with Cardiovascular Effects in Healthy Young Men.

Am. J. Respir. Crit. Care Med.

169: 934-940.

Visibility

Visibility can be defined as the degree to which the atmosphere is transparent to visible light. Airborne particles degrade visibility by scattering and absorbing light. Visibility is important because it has direct significance to people's enjoyment of daily activities in all parts of the country. Individuals value good visibility for the well-being it provides them directly, where they live and work and in places where they enjoy recreational opportunities.

Visibility is also highly valued in significant natural areas such as national parks and wilderness areas and special emphasis is given to protecting visibility in these areas. For more information on visibility, see the final 2004 PM AQCD as well as the 2005 PM Staff Paper.

24 25

EPA is pursuing a two-part strategy to address visibility. First, to address the welfare effects of PM on visibility, EPA has set secondary PM

2.5

standards which act in conjunction with the establishment of a regional haze program. In setting this secondary standard, EPA has concluded that PM

2.5

causes adverse effects on visibility in various locations, depending on PM concentrations and factors such as chemical composition and average relative humidity. Second, section 169 of the Clean Air Act provides additional authority to address existing visibility impairment and prevent future visibility impairment in the 156 national parks, forests and wilderness areas categorized as mandatory class I federal areas (62 FR 38680-81, July 18, 1997).

In July 1999, the regional haze rule (64 FR 35714) was put in place to protect the visibility in mandatory class I federal areas. Visibility can be said to be impaired in both PM

2.5

nonattainment areas and mandatory class I federal areas.

These areas are defined in section 162 of the Act as those national parks exceeding 6,000 acres, wilderness areas and memorial parks exceeding 5,000 acres, and all international parks which were in existence on August 7, 1977.

Current Visibility Impairment

As of March 12, 2008, over 88 million people live in nonattainment areas for the 1997 PM

2.5

NAAQS.

These populations, as well as large numbers of individuals who travel to these areas, are likely to experience visibility impairment. In addition, while visibility trends have improved in mandatory class I federal areas the most recent data show that these areas continue to suffer from visibility impairment.

In summary, visibility impairment is experienced throughout the U.S., in multi-state regions, urban areas, and remote mandatory class I federal areas.

29 30

Population numbers are from 2000 census data.

U.S. EPA (2002) Latest Findings on National Air Quality—2002 Status and Trends. EPA 454/K-03-001.

U.S. EPA, Air Quality Designations and Classifications for the Fine Particles (PM

2.5

) National Ambient Air Quality Standards, December 17, 2004. (70 FR 943, Jan 5. 2005) This document is also available on the web at:

http://www.epa.gov/pmdesignations/

U.S. EPA. Regional Haze Regulations, July 1, 1999. (64 FR 35714, July 1, 1999).

Future Visibility Impairment

Air quality modeling conducted for this final rule was used to project visibility conditions in 133 mandatory class I federal areas across the U.S. in 2020 and 2030. The results indicate that improvements in visibility will occur in the future, although all areas will continue to have annual average deciview levels above background in 2020 and 2030. Chapter 2 of the RIA contains more detail on the visibility portion of the air quality modeling.

Atmospheric Deposition

Wet and dry deposition of ambient particulate matter delivers a complex mixture of metals (e.g., mercury, zinc, lead, nickel, aluminum, cadmium), organic compounds (e.g., POM, dioxins, furans) and inorganic compounds (e.g., nitrate, sulfate) to terrestrial and aquatic ecosystems. The chemical form of the compounds deposited is impacted by a variety of factors including ambient conditions (e.g., temperature, humidity, oxidant levels) and the sources of the material. Chemical and physical transformations of the particulate compounds occur in the atmosphere as well as the media onto which they deposit. These transformations in turn influence the fate, bioavailability and potential toxicity of these compounds. Atmospheric deposition has been identified as a key component of the environmental and human health hazard posed by several pollutants including mercury, dioxin and PCBs.

U.S. EPA (2000) Deposition of Air Pollutants to the Great Waters: Third Report to Congress. Office of Air Quality Planning and Standards. EPA-453/R-00-0005. This document is available in Docket EPA-HQ-OAR-2003-0190.

Adverse impacts on water quality can occur when atmospheric contaminants deposit to the water surface or when material deposited on the land enters a water body through runoff. Potential impacts of atmospheric deposition to water bodies include those related to both nutrient and toxic inputs. Adverse effects to human health and welfare can occur from the addition of excess particulate nitrate nutrient enrichment, which contributes to toxic algae blooms and zones of depleted oxygen, which can lead to fish kills, frequently in coastal waters. Particles contaminated with heavy metals or other toxins may lead to the ingestion of contaminated fish, ingestion of contaminated water, damage to the marine ecology, and limited recreational uses. Several studies have been conducted in U.S. coastal waters and in the Great Lakes Region in which the role of ambient PM deposition and runoff is investigated.

32 33 34 35 36

U.S. EPA (2004) National Coastal Condition Report II. Office of Research and Development/ Office of Water. EPA-620/R-03/002. This document is available in Docket EPA-HQ-OAR-2003-0190.

Gao, Y., E.D. Nelson, M.P. Field,

et al.

2002. Characterization of atmospheric trace elements on PM

2.5

particulate matter over the New York-New Jersey harbor estuary.

Atmos. Environ.

36: 1077-1086.

Kim, G., N. Hussain, J.R. Scudlark, and T.M. Church. 2000. Factors influencing the atmospheric depositional fluxes of stable Pb, 210Pb, and 7Be into Chesapeake Bay.

J. Atmos. Chem.

36: 65-79.

Lu, R., R.P. Turco, K. Stolzenbach,

et al.

2003. Dry deposition of airborne trace metals on the Los Angeles Basin and adjacent coastal waters.

J. Geophys. Res.

108(D2, 4074): AAC 11-1 to 11-24.

Marvin, C.H., M.N. Charlton, E.J. Reiner,

et al.

2002. Surficial sediment contamination in Lakes Erie and Ontario: A comparative analysis.

J. Great Lakes Res.

28(3): 437-450.

Adverse impacts on soil chemistry and plant life have been observed for areas heavily impacted by atmospheric deposition of nutrients, metals and acid species, resulting in species shifts, loss of biodiversity, forest decline and damage to forest productivity. Potential impacts also include adverse effects to human health through ingestion of contaminated vegetation or livestock (as in the case for dioxin deposition), reduction in crop yield, and limited use of land due to contamination.

Materials Damage and Soiling

The deposition of airborne particles can reduce the aesthetic appeal of buildings and culturally important articles through soiling, and can contribute directly (or in conjunction with other pollutants) to structural damage by means of corrosion or erosion.

Particles affect materials principally by promoting and accelerating the corrosion of metals, by degrading paints, and by deteriorating building materials such as concrete and limestone. Particles contribute to these effects because of their electrolytic, hygroscopic, and acidic properties, and their ability to adsorb corrosive gases (principally sulfur dioxide). The rate of metal corrosion depends on a number of factors, including the deposition rate and nature of the pollutant; the influence of the metal protective

corrosion film; the amount of moisture present; variability in the electrochemical reactions; the presence and concentration of other surface electrolytes; and the orientation of the metal surface.

U.S EPA (2005) Review of the National Ambient Air Quality Standards for Particulate Matter: Policy Assessment of Scientific and Technical Information, OAQPS Staff Paper. This document is available in Docket EPA-HQ-OAR-2003-0190.

Current and Projected PM

2.5

Levels

2.5

concentrations exceeding the level of the PM

2.5

NAAQS occur in many parts of the country.

In 2005 EPA designated 39 nonattainment areas for the 1997 PM

2.5

NAAQS (70 FR 943, January 5, 2005). These areas are comprised of 208 full or partial counties with a total population exceeding 88 million. The 1997 PM

2.5

NAAQS was revised and the 2006 PM

2.5

NAAQS became effective on December 18, 2006. Table II-2 presents the number of counties in areas currently designated as nonattainment for the 1997 PM

2.5

NAAQS as well as the number of additional counties that have design values greater than the 2006 PM

2.5

NAAQS.

A listing of the PM

2.5

nonattainment areas is included in the RIA for this rule.

Table II-2—Counties With Design Values Greater Than the 2006 PM

2.5

NAAQS Based on 2003-2005 Air Quality Data

Nonattainment areas/other violating counties

Number of

counties

Population

1997 PM

2.5

Standards: Counties within the 39 areas currently designated as nonattainment

208

88,394,000

2006 PM

2.5

Standards: Additional counties that would not meet the 2006 NAAQS

18,198,676

Total

257

106,595,676

Notes:

Population numbers are from 2000 census data.

Attainment designations for 2006 PM

2.5

NAAQS have not yet been made. Nonattainment for the 2006 PM

2.5

NAAQS will be based on 3 years of air quality data from later years. Also, the county numbers in the table includes only the counties with monitors violating the 2006 PM

2.5

NAAQS. The numbers in this table may be an underestimate of the number of counties and populations that will eventually be included in areas with multiple counties designated nonattainment.

Areas designated as not attaining the 1997 PM

2.5

NAAQS will need to attain the 1997 standards in the 2010 to 2015 time frame, and then maintain them thereafter. The attainment dates associated with the potential new 2006 PM

2.5

nonattainment areas are likely to be in the 2014 to 2019 timeframe. The emission standards finalized in this action become effective as early as 2009 making the inventory reductions from this rulemaking useful to states in attaining or maintaining the PM

2.5

NAAQS.

EPA has already adopted many emission control programs that are expected to reduce ambient PM

2.5

levels and which will assist in reducing the number of areas that fail to achieve the PM

2.5

NAAQS. Even so, our air quality modeling for this final rule projects that in 2020, with all current controls but excluding the reductions achieved through this rule, up to 11 counties with a population of over 24 million may not attain the current annual PM

2.5

standard of 15 μg/m

. These numbers do not account for additional areas that have air quality measurements within 10 percent of the annual PM

2.5

standard. These areas, although not violating the standards, will also benefit from the additional reductions from this rule ensuring long term maintenance of the PM

2.5

NAAQS.

Air quality modeling performed for this final rule shows the emissions reductions will improve both the average and population-weighted average PM

2.5

concentrations for the U.S. On a population-weighted basis, the average modeled future-year annual PM

2.5

design value (DV) for all counties is expected to decrease by 0.02 μg/m

in 2020 and 2030. There are areas with larger decreases in their future-year annual PM

2.5

DV, for instance the Chicago region will experience a 0.08 μ g/m

reduction by 2030. The air quality modeling methodology and the projected reductions are discussed in more detail in Chapter 2 of the RIA.

B. Air Toxics

Small SI and Marine SI emissions also contribute to ambient levels of air toxics known or suspected as human or animal carcinogens, or that have noncancer health effects. These air toxics include benzene, 1, 3-butadiene, formaldehyde, acetaldehyde, acrolein, polycyclic organic matter (POM), and naphthalene. All of these compounds, except acetaldehyde, were identified as national or regional cancer risk or noncancer hazard drivers in the 1999 National-Scale Air Toxics Assessment (NATA) and have significant inventory contributions from mobile sources. That is, for a significant portion of the population, these compounds pose a significant portion of the total cancer and noncancer risk from breathing outdoor air toxics. In addition, human exposure to toxics from spark-ignition engines also occurs as a result of operating these engines and from intrusion of emissions in residential garages into attached indoor spaces.

39 40

The emission reductions from Small SI and Marine SI engines that are finalized in this rulemaking will help reduce exposure to these harmful substances.

Baldauf, R.; Fortune, C.; Weinstein, J.; Wheeler, M.; Blanchard, B. (2006) Air contaminant exposures during the operation of lawn and garden equipment. J Expos Sci Environ Epidmeiol 16: 362-370.

Isbell, M.; Ricker, J.; Gordian, M.E.; Duff, L.K. (1999) Use of biomarkers in an indoor air study: lack of correlation between aromatic VOCs with respective urinary biomarkers. Sci Total Environ 241: 151-159.

Benzene: The EPA's IRIS database lists benzene as a known human carcinogen (causing leukemia) by all routes of exposure, and concludes that exposure is associated with additional health effects, including genetic changes in both humans and animals and increased proliferation of bone marrow cells in mice.

41 42 43

EPA states in its IRIS database that data indicate a causal relationship between benzene exposure and acute lymphocytic leukemia and suggest a relationship between benzene exposure and chronic non-lymphocytic

leukemia and chronic lymphocytic leukemia. The International Agency for Research on Carcinogens (IARC) has determined that benzene is a human carcinogen and the U.S. Department of Health and Human Services (DHHS) has characterized benzene as a known human carcinogen.

44 45

U.S. EPA. 2000. Integrated Risk Information System File for Benzene. This material is available electronically at

http://www.epa.gov/iris/subst/0276.htm

International Agency for Research on Cancer (IARC). 1982. Monographs on the evaluation of carcinogenic risk of chemicals to humans, Volume 29, Some industrial chemicals and dyestuffs, World Health Organization, Lyon, France, p. 345-389.

Irons, R.D.; Stillman, W.S.; Colagiovanni, D.B.; Henry, V.A. 1992. Synergistic action of the benzene metabolite hydroquinone on myelopoietic stimulating activity of granulocyte/macrophage colony-stimulating factor in vitro, Proc. Natl. Acad. Sci. 89:3691-3695.

International Agency for Research on Cancer (IARC). 1987. Monographs on the evaluation of carcinogenic risk of chemicals to humans, Volume 29, Supplement 7, Some industrial chemicals and dyestuffs, World Health Organization, Lyon, France.

U.S. Department of Health and Human Services National Toxicology Program 11th Report on Carcinogens available at:

http://ntp.niehs.nih.gov/go/16183

A number of adverse noncancer health effects including blood disorders, such as preleukemia and aplastic anemia, have also been associated with long-term exposure to benzene.

46 47

The most sensitive noncancer effect observed in humans, based on current data, is the depression of the absolute lymphocyte count in blood.

48 49

In addition, recent work, including studies sponsored by the Health Effects Institute (HEI), provides evidence that biochemical responses are occurring at lower levels of benzene exposure than previously known.

50 51 52 53

EPA's IRIS program has not yet evaluated these new data.

Aksoy, M. (1989). Hematotoxicity and carcinogenicity of benzene. Environ. Health Perspect. 82: 193-197.

Goldstein, B.D. (1988). Benzene toxicity. Occupational medicine. State of the Art Reviews. 3: 541-554.

Rothman, N., G.L. Li, M. Dosemeci, W.E. Bechtold, G.E. Marti, Y.Z. Wang, M. Linet, L.Q. Xi, W. Lu, M.T. Smith, N. Titenko-Holland, L.P. Zhang, W. Blot, S.N. Yin, and R.B. Hayes (1996) Hematotoxicity among Chinese workers heavily exposed to benzene. Am. J. Ind. Med. 29: 236-246.

U.S. EPA (2002) Toxicological Review of Benzene (Noncancer Effects). Environmental Protection Agency, Integrated Risk Information System (IRIS), Research and Development, National Center for Environmental Assessment, Washington DC. This material is available electronically at

http://www.epa.gov/iris/subst/0276.htm

Qu, O.; Shore, R.; Li, G.; Jin, X.; Chen, C.L.; Cohen, B.; Melikian, A.; Eastmond, D.; Rappaport, S.; Li, H.; Rupa, D.; Suramaya, R.; Songnian, W.; Huifant, Y.; Meng, M.; Winnik, M.; Kwok, E.; Li, Y.; Mu, R.; Xu, B.; Zhang, X.; Li, K. (2003) HEI Report 115, Validation & Evaluation of Biomarkers in Workers Exposed to Benzene in China.

Qu, Q., R. Shore, G. Li, X. Jin, L.C. Chen, B. Cohen,

et al.

(2002) Hematological changes among Chinese workers with a broad range of benzene exposures. Am. J. Industr. Med. 42: 275-285.

Lan, Qing, Zhang, L., Li, G., Vermeulen, R.,

et al.

(2004) Hematotoxically in Workers Exposed to Low Levels of Benzene. Science 306: 1774-1776.

Turtletaub, K.W. and Mani, C. (2003) Benzene metabolism in rodents at doses relevant to human exposure from Urban Air. Research Reports Health Effect Inst. Report No.113.

1,3-Butadiene: EPA has characterized 1,3-butadiene as carcinogenic to humans by inhalation.

54 55

The IARC has determined that 1,3-butadiene is a human carcinogen and the U.S. DHHS has characterized 1,3-butadiene as a known human carcinogen.

56 57

There are numerous studies consistently demonstrating that 1,3-butadiene is metabolized into genotoxic metabolites by experimental animals and humans. The specific mechanisms of 1,3-butadiene-induced carcinogenesis are unknown; however, the scientific evidence strongly suggests that the carcinogenic effects are mediated by genotoxic metabolites. Animal data suggest that females may be more sensitive than males for cancer effects associated with 1,3-butadiene exposure; there are insufficient data in humans from which to draw conclusions about sensitive subpopulations. 1,3-butadiene also causes a variety of reproductive and developmental effects in mice; no human data on these effects are available. The most sensitive effect was ovarian atrophy observed in a lifetime bioassay of female mice.

U.S. EPA (2002) Health Assessment of 1,3-Butadiene. Office of Research and Development, National Center for Environmental Assessment, Washington Office, Washington, DC. Report No. EPA600-P-98-001F. This document is available electronically at

http://www.epa.gov/iris/supdocs/buta-sup.pdf

U.S. EPA (2002) Full IRIS Summary for 1,3-butadiene (CASRN 106-99-0). Environmental Protection Agency, Integrated Risk Information System (IRIS), Research and Development, National Center for Environmental Assessment, Washington, DC

http://www.epa.gov/iris/subst/0139.htm

International Agency for Research on Cancer (IARC) (1999) Monographs on the evaluation of carcinogenic risk of chemicals to humans, Volume 71, Re-evaluation of some organic chemicals, hydrazine and hydrogen peroxide and Volume 97 (in preparation), World Health Organization, Lyon, France.

U.S. Department of Health and Human Services (2005) National Toxicology Program 11th Report on Carcinogens available at:

ntp.niehs.nih.gov/index.cfm?objectid=32BA9724-F1F6-975E-7FCE50709CB4C932

Bevan, C.; Stadler, J.C.; Elliot, G.S.;

et al.

(1996) Subchronic toxicity of 4-vinylcyclohexene in rats and mice by inhalation. Fundam. Appl. Toxicol. 32:1-10.

Formaldehyde: Since 1987, EPA has classified formaldehyde as a probable human carcinogen based on evidence in humans and in rats, mice, hamsters, and monkeys.

EPA is currently reviewing recently published epidemiological data. For instance, research conducted by the National Cancer Institute (NCI) found an increased risk of nasopharyngeal cancer and lymphohematopoietic malignancies such as leukemia among workers exposed to formaldehyde.

60 61

NCI is currently performing an update of these studies. A recent National Institute of Occupational Safety and Health (NIOSH) study of garment workers also found increased risk of death due to leukemia among workers exposed to formaldehyde.

Extended follow-up of a cohort of British chemical workers did not find evidence of an increase in nasopharyngeal or lymphohematopoietic cancers, but a continuing statistically significant excess in lung cancers was reported.

Recently, the IARC re-classified formaldehyde as a human carcinogen (Group 1).

U.S. EPA (1987) Assessment of Health Risks to Garment Workers and Certain Home Residents from Exposure to Formaldehyde, Office of Pesticides and Toxic Substances, April 1987.

Hauptmann, M.; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; Blair, A. 2003. Mortality from lymphohematopoetic malignancies among workers in formaldehyde industries. Journal of the National Cancer Institute 95: 1615-1623.

Hauptmann, M.; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; Blair, A. 2004. Mortality from solid cancers among workers in formaldehyde industries. American Journal of Epidemiology 159: 1117-1130.

Pinkerton, L. E. 2004. Mortality among a cohort of garment workers exposed to formaldehyde: an update. Occup. Environ. Med. 61: 193-200.

Coggon, D, EC Harris, J Poole, KT Palmer. 2003. Extended follow-up of a cohort of British chemical workers exposed to formaldehyde. J National Cancer Inst. 95:1608-1615.

International Agency for Research on Cancer (IARC). 2006. Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol. Volume 88. (in preparation), World Health Organization, Lyon, France.

Formaldehyde exposure also causes a range of noncancer health effects, including irritation of the eyes (burning and watering of the eyes), nose and throat. Effects from repeated exposure in humans include respiratory tract irritation, chronic bronchitis and nasal epithelial lesions such as metaplasia and loss of cilia. Animal studies suggest that formaldehyde may also cause airway inflammation—including eosinophil infiltration into the airways. There are several studies that suggest that formaldehyde may increase the risk of asthma—particularly in the young.

65 66

Agency for Toxic Substances and Disease Registry (ATSDR). 1999. Toxicological profile for Formaldehyde. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

http://www.atsdr.cdc.gov/toxprofiles/tp111.html

WHO (2002) Concise International Chemical Assessment Document 40: Formaldehyde. Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organization, and the World Health Organization, and produced within the framework of the Inter-Organization Programme for the Sound Management of Chemicals. Geneva.

Acetaldehyde: Acetaldehyde is classified in EPA's IRIS database as a probable human carcinogen, based on nasal tumors in rats, and is considered toxic by the inhalation, oral, and intravenous routes.

Acetaldehyde is

reasonably anticipated to be a human carcinogen by the U.S. DHHS in the 11th Report on Carcinogens and is classified as possibly carcinogenic to humans (Group 2B) by the IARC.

68 69

EPA is currently conducting a reassessment of cancer risk from inhalation exposure to acetaldehyde.

U.S. EPA. 191. Integrated Risk Information System File of Acetaldehyde. Research and Development, National Center for Environmental Assessment, Washington, DC. This material is available electronically at

http://www.epa.gov/iris/subst/0290.htm

U.S. Department of Health and Human Services National Toxicology Program 11th Report on Carcinogens available at:

ntp.niehs.nih.gov/index.cfm?objectid=32BA9724-F1F6-975E-7FCE50709CB4C932

International Agency for Research on Cancer (IARC). 1999. Re-evaluation of some organic chemicals, hydrazine, and hydrogen peroxide. IARC Monographs on the Evaluation of Carcinogenic Risk of Chemical to Humans, Vol 71. Lyon, France.

The primary noncancer effects of exposure to acetaldehyde vapors include irritation of the eyes, skin, and respiratory tract.

In short-term (4 week) rat studies, degeneration of olfactory epithelium was observed at various concentration levels of acetaldehyde exposure.

71 72

Data from these studies were used by EPA to develop an inhalation reference concentration. Some asthmatics have been shown to be a sensitive subpopulation to decrements in functional expiratory volume (FEV1 test) and bronchoconstriction upon acetaldehyde inhalation.

The agency is currently conducting a reassessment of the health hazards from inhalation exposure to acetaldehyde.

U.S. EPA. 1991. Integrated Risk Information System File of Acetaldehyde. This material is available electronically at

http://www.epa.gov/iris/subst/0290.htm.

Appleman, L. M., R. A. Woutersen, V. J. Feron, R. N. Hooftman, and W. R. F. Notten. 1986. Effects of the variable versus fixed exposure levels on the toxicity of acetaldehyde in rats.

J. Appl. Toxicol.

6: 331-336.

Appleman, L.M., R.A. Woutersen, and V.J. Feron. 1982. Inhalation toxicity of acetaldehyde in rats. I. Acute and subacute studies.

Toxicology.

23: 293-297.

Myou, S.; Fujimura, M.; Nishi K.; Ohka, T.; and Matsuda, T. 1993. Aerosolized acetaldehyde induces histamine-mediated bronchoconstriction in asthmatics.

Am. Rev. Respir.Dis.

148(4 Pt 1): 940-3.

Acrolein: EPA determined in 2003 that the human carcinogenic potential of acrolein could not be determined because the available data were inadequate. No information was available on the carcinogenic effects of acrolein in humans and the animal data provided inadequate evidence of carcinogenicity.

The IARC determined in 1995 that acrolein was not classifiable as to its carcinogenicity in humans.

U.S. EPA. 2003. Integrated Risk Information System File of Acrolein. Research and Development, National Center for Environmental Assessment, Washington, DC. This material is available at

http://www.epa.gov/iris/subst/0364.htm

International Agency for Research on Cancer (IARC). 1995. Monographs on the evaluation of carcinogenic risk of chemicals to humans, Volume 63, Dry cleaning, some chlorinated solvents and other industrial chemicals, World Health Organization, Lyon, France.

Acrolein is extremely acrid and irritating to humans when inhaled, with acute exposure resulting in upper respiratory tract irritation, mucus hypersecretion and congestion. Levels considerably lower than 1 ppm (2.3 mg/m

) elicit subjective complaints of eye and nasal irritation and a decrease in the respiratory rate.

76 77

Lesions to the lungs and upper respiratory tract of rats, rabbits, and hamsters have been observed after subchronic exposure to acrolein. Based on animal data, individuals with compromised respiratory function (e.g., emphysema, asthma) are expected to be at increased risk of developing adverse responses to strong respiratory irritants such as acrolein. This was demonstrated in mice with allergic airway-disease by comparison to non-diseased mice in a study of the acute respiratory irritant effects of acrolein.

Weber-Tschopp, A; Fischer, T; Gierer, R; et al. (1977) Experimentelle reizwirkungen von Acrolein auf den Menschen. Int Arch Occup Environ Hlth 40(2):117-130. In German.

Sim, VM; Pattle, RE. (1957) Effect of possible smog irritants on human subjects. J Am Med Assoc 165(15):1908-1913.

Morris JB, Symanowicz PT, Olsen JE, et al. 2003. Immediate sensory nerve-mediated respiratory responses to irritants in healthy and allergic airway-diseased mice. J Appl Physiol 94(4):1563-1571.

EPA is currently in the process of conducting an assessment of acute exposure effects for acrolein. The intense irritancy of this carbonyl has been demonstrated during controlled tests in human subjects, who suffer intolerable eye and nasal mucosal sensory reactions within minutes of exposure.

Sim VM, Pattle RE. Effect of possible smog irritants on human subjects JAMA165: 1980-2010, 1957.

Polycyclic Organic Matter (POM): POM is generally defined as a large class of organic compounds which have multiple benzene rings and a boiling point greater than 100 degrees Celsius. Many of the compounds included in the class of compounds known as POM are classified by EPA as probable human carcinogens based on animal data. One of these compounds, naphthalene, is discussed separately below. Polycyclic aromatic hydrocarbons (PAHs) are a subset of POM that contain only hydrogen and carbon atoms. A number of PAHs are known or suspected carcinogens. Recent studies have found that maternal exposures to PAHs (a subclass of POM) in a population of pregnant women were associated with several adverse birth outcomes, including low birth weight and reduced length at birth, as well as impaired cognitive development at age three.

80 81

EPA has not yet evaluated these recent studies.

Perera, F.P.; Rauh, V.; Tsai, W-Y.; et al. (2002) Effect of transplacental exposure to environmental pollutants on birth outcomes in a multiethnic population.

Environ Health Perspect.

111: 201-205.

Perera, F.P.; Rauh, V.; Whyatt, R.M.; Tsai, W.Y.; Tang, D.; Diaz, D.; Hoepner, L.; Barr, D.; Tu, Y.H.; Camann, D.; Kinney, P. (2006) Effect of prenatal exposure to airborne polycyclic aromatic hydrocarbons on neurodevelopment in the first 3 years of life among inner-city children.

Environ Health Perspect

114: 1287-1292.

Naphthalene: Naphthalene is found in small quantities in gasoline and diesel fuels. Naphthalene emissions have been measured in larger quantities in both gasoline and diesel exhaust compared with evaporative emissions from mobile sources, indicating it is primarily a product of combustion. EPA recently released an external review draft of a reassessment of the inhalation carcinogenicity of naphthalene based on a number of recent animal carcinogenicity studies.

The draft reassessment recently completed external peer review.

Based on external peer review comments received to date, additional analyses are being undertaken. This external review draft does not represent official agency opinion and was released solely for the purposes of external peer review and public comment. Once EPA evaluates public and peer reviewer comments, the document will be revised. The National Toxicology Program listed naphthalene as “reasonably anticipated to be a human carcinogen” in 2004 on the basis of bioassays reporting clear evidence of carcinogenicity in rats and some evidence of carcinogenicity in mice.

California EPA has released a new risk assessment for naphthalene, and the IARC has reevaluated naphthalene and re-classified it as Group 2B: possibly carcinogenic to humans.

Naphthalene

also causes a number of chronic non-cancer effects in animals, including abnormal cell changes and growth in respiratory and nasal tissues.

U.S. EPA (2004) Toxicological Review of Naphthalene (Reassessment of the Inhalation Cancer Risk), Environmental Protection Agency, Integrated Risk Information System, Research and Development, National Center for Environmental Assessment, Washington, DC. This material is available electronically at

http://www.epa.gov/iris/subst/0436.htm.

Oak Ridge Institute for Science and Education (2004) External Peer Review for the IRIS Reassessment of the Inhalation Carcinogenicity of Naphthalene. August 2004.

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=84403

National Toxicology Program (NTP). (2004). 11th Report on Carcinogens. Public Health Service, U.S. Department of Health and Human Services, Research Triangle Park, NC. Available from:

http://ntp-server.niehs.nih.gov.

International Agency for Research on Cancer (IARC) (2002) Monographs on the Evaluation of the Carcinogenic Risk of Chemicals for Humans. Vol. 82. Lyon, France.

U.S. EPA (1998) Toxicological Review of Naphthalene, Environmental Protection Agency, Integrated Risk Information System, Research and Development, National Center for Environmental Assessment, Washington, DC. This material is available electronically at

http://www.epa.gov/iris/subst/0436.htm

The standards finalized in this action will reduce air toxics emitted from these engines, vessels and equipment. These emissions reductions will help to mitigate some of the adverse health effects associated with their operation.

C. Carbon Monoxide

CO is a colorless, odorless gas produced through the incomplete combustion of carbon-based fuels. The current primary NAAQS for CO are 35 ppm for the 1-hour average and nine ppm for the 8-hour average. These values are not to be exceeded more than once per year.

We previously found that emissions from nonroad engines contribute significantly to CO concentrations in more than one nonattainment area (59 FR 31306, June 17, 1994). We have also previously found that emissions from Small SI engines contribute to CO concentrations in more than one nonattainment area. We are adopting a finding, based on the information in this section and in Chapters 2 and 3 of the Final RIA, that emissions from Marine SI engines and vessels likewise contribute to CO concentrations in more than one CO nonattainment area.

Carbon monoxide enters the bloodstream through the lungs, forming carboxyhemoglobin and reducing the delivery of oxygen to the body's organs and tissues. The health threat from CO is most serious for those who suffer from cardiovascular disease, particularly those with angina or peripheral vascular disease. Healthy individuals also are affected, but only at higher CO levels. Exposure to elevated CO levels is associated with impairment of visual perception, work capacity, manual dexterity, learning ability and performance of complex tasks. Carbon monoxide also contributes to ozone nonattainment since carbon monoxide reacts photochemically in the atmosphere to form ozone.

Additional information on CO related health effects can be found in the Carbon Monoxide Air Quality Criteria Document (CO AQCD).

U.S. EPA (2000). Air Quality Criteria for Carbon Monoxide, EPA/600/P-99/001F. This document is available in Docket EPA-HQ-OAR-2004-0008.

In addition to health effects from chronic exposure to ambient CO levels, acute exposures to higher levels are also a problem, see the Final RIA for additional information. In recent years a substantial number of CO poisonings and deaths have occurred on and around recreational boats across the nation.

The actual number of deaths attributable to CO poisoning while boating is difficult to estimate because CO-related deaths in the water may be labeled as drowning. An interagency team consisting of the National Park Service, the U.S. Department of the Interior, and the National Institute for Occupational Safety and Health maintains a record of published CO-related fatal and nonfatal poisonings.

Between 1984 and 2004, 113 CO-related deaths and 458 non-fatal CO poisonings have been identified based on hospital records, press accounts and other information. Deaths have been attributed to exhaust from both onboard generators and propulsion engines. Houseboats, cabin cruisers, and ski boats are the most common types of boats associated with CO poisoning cases. These incidents have prompted other federal agencies, including the United States Coast Guard and National Park Service, to issue advisory statements and other interventions to boaters to avoid excessive CO exposure.

Mott, J.S.; Wolfe, M.I.; Alverson, C.J.; Macdonald, S.C.; Bailey, C.R.; Ball, L.B.; Moorman, J.E.; Somers, J.H.; Mannino, D.M.; Redd, S.C. (2002) National Vehicle Emissions Policies and Practices and Declining US Carbon Monoxide-Related Mortality.

JAMA

288:988-995.

National Park Service; Department of the Interior; National Institute for Occupational Safety and Health. (2004) Boat-related carbon monoxide poisonings. This document is available electronically at

http://safetynet.smis.doi.gov/thelistbystate10-19-04.pdf

and in docket EPA-HQ-OAR-2004-0008.

U.S Department of the Interior. (2004) Carbon monoxide dangers from generators and propulsion engines. On-board boats—compilation of materials. This document is available online at

http://safetynet.smis.doi.gov/COhouseboats.htm

and in docket EPA-HQ-OAR-2004-0008.

As of March 12, 2008, there were approximately 850,000 people living in 4 areas (which include 5 counties) designated as nonattainment for CO.

The CO nonattainment areas are presented in the Final RIA.

Population numbers are from 2000 census data.

EPA's NONROAD model indicates that Marine SI emissions are present in each of the CO nonattainment areas and thus contribute to CO concentrations in those nonattainment areas. The CO contribution from Marine SI engines in classified CO nonattainment areas is presented in Table II-3.

Table II-3—CO Emissions From Marine SI Engines and Vessels in Classified CO Nonattainment Areas

Area

County

Category

CO (short tons in 2005)

Las Vegas, NV

Clark

Marine SI

3,016

Reno, NV

Washoe

Marine SI

3,494

El Paso, TX

El Paso

Marine SI

Source: U.S. EPA, NONROAD 2005 model.

This table does not include Salem, OR which is an unclassified CO nonattainment area.

Based on the national inventory numbers in Chapter 3 of the Final RIA and the local inventory numbers described in this section, we find that emissions of CO from Marine SI engines and vessels contribute to CO concentrations in more than one CO nonattainment area.

III. Sterndrive and Inboard Marine Engines

A. Overview

This section applies to sterndrive and inboard marine (SD/I) engines. Sterndrive and inboard engines are spark-ignition engines typically derived from automotive engine blocks for which a manufacturer will take steps to “marinize” the engine for use in marine applications. This marinization process includes choosing and optimizing the fuel management system, configuring a marine cooling system, adding intake and exhaust manifolds, and adding accessory drives and units. These engines typically have water-jacketed

exhaust systems to keep surface temperatures low. Ambient surface water (seawater or freshwater) is generally added to the exhaust gases before the mixture is expelled under water.

As described in Section I, the initial rulemaking to set standards for Marine SI engines did not include final emission standards for SD/I engines. In that rulemaking, we finalized the finding under Clean Air Act section 213(a)(3) that all Marine SI engines cause or contribute to ozone concentrations in two or more ozone nonattainment areas in the United States. However, because uncontrolled SD/I engines appeared to be a low-emission alternative to outboard and personal watercraft engines in the marketplace, even after the emission standards for these engines were fully phased in, we decided to set emission standards only for outboard and personal watercraft engines. At that time, outboard and personal watercraft engines were almost all two-stroke engines with much higher emission rates compared to the SD/I engines, which were all four-stroke engines. We pointed out in that initial rulemaking that we wanted to avoid imposing costs on SD/I engines that could cause a market shift to increased use of the higher-emitting outboard engines, which will undermine the broader goal of achieving the greatest degree of emission control from the full set of Marine SI engines.

We believe this is an appropriate time to set standards for SD/I engines, for several reasons. First, the available technology for SD/I engines has developed significantly, so we are now able to anticipate substantial emission reductions. With the simultaneous developments in technology for outboard and personal watercraft engines, we can set standards that achieve substantial emission reductions from all Marine SI engines. Second, now that California has adopted standards for SD/I engines, the cost impact of setting new standards for manufacturers serving the California market is generally limited to the hardware costs of adding emission control technology; these manufacturers will be undergoing a complete redesign effort for these engines to meet the California standards. Third, while an emission control program for SD/I engines will increase the price of these engines, we no longer think this will result in a market shift to higher-emitting outboard engines. The economic impact analysis performed for this final rule, summarized in Section XII, suggests that the prices will increase less than 1 percent and sales will be impacted by less than 2 percent. It is also possible that SD/I engine manufacturers may promote higher fuel efficiency and other performance advantages of compliant engines which would allow them to promote these engines as having a greater value and justifying these small expected price increases. As a result, we believe we can achieve the maximum emission reductions from Marine SI engines by setting standards for SD/I engines based on the use of catalyst technology at the same time that we adopt more stringent standards for outboard and personal watercraft engines.

As described in Section II, we are adopting the finding under Clean Air Act section 213(a)(3) that Marine SI engines cause or contribute to CO concentrations in two or more nonattainment areas of the United States. We believe the new CO standards will also reduce the exposure of individual boaters and bystanders to potentially dangerous CO levels.

We believe catalyst technology is available for achieving the new standards. Catalysts have been used for decades in automotive applications to reduce emissions, and catalyst manufacturers have continued to develop and improve this technology. Design issues for using catalysts in marine applications are primarily centered on packaging catalysts in the water-jacketed, wet exhaust systems seen on most SD/I engines. Section III.G discusses recent development work that has shown success in packaging catalysts in SD/I applications. In addition, there are ongoing efforts in evaluating catalyst technology in SD/I engines being sponsored by the marine industry, U.S. Coast Guard, and California ARB.

We are adopting the regulatory requirements for marine spark-ignition engines in 40 CFR part 1045. These requirements are similar to the regulations that have been in place for outboard and personal watercraft engines for several years, but include updated certification procedures, as described in Section IV.A. Engines and vessels subject to part 1045 are also subject to the general compliance provisions in 40 CFR part 1068. These include prohibited acts and penalties, exemptions and importation provisions, selective enforcement audits, defect reporting and recall, and hearing procedures. See Section VIII of the preamble to the proposed rule for further discussion of these general compliance provisions.

B. Engines Covered by This Rule

(1) Definition of Sterndrive and Inboard Engines

For the purpose of this regulation, SD/I engines encompass all spark-ignition marine propulsion engines that are not outboard or personal watercraft engines. A discussion of the revised definitions for outboard and personal watercraft engines is in Section IV.B. We consider all the following to be SD/I engines: inboard, sterndrive (also known as inboard/outboard), airboat engines, and jet boat engines.

The definitions for sterndrive and inboard engines at 40 CFR part 91 are presented below:

• Sterndrive engine means a four stroke Marine SI engine that is designed such that the drive unit is external to the hull of the marine vessel, while the engine is internal to the hull of the marine vessel.

• Inboard engine means a four stroke Marine SI engine that is designed such that the propeller shaft penetrates the hull of the marine vessel while the engine and the remainder of the drive unit is internal to the hull of the marine vessel.

We are amending the above definitions for determining which exhaust emission standards apply to spark-ignition marine engines in 2010. The new definition establishes a single term to include sterndrive and inboard engines together as a single engine category. The new definition for sterndrive/inboard also is drafted to include all engines not otherwise classified as outboard or personal watercraft engines.

The new definition has several noteworthy impacts. First, it removes a requirement that only four-stroke engines can qualify as sterndrive/inboard engines. We believe limiting the definition to include only four-stroke engines is unnecessarily restrictive and could create an incentive to use two-stroke (or rotary) engines to avoid catalyst-based standards. Second, it removes limitations caused by reference to propellers. The definition should not refer specifically to propellers, because there are other propulsion drives on marine vessels, such as jet drives, that could be used with SD/I engines. Third, as explained in the section on the OB/PWC definitions, the new definitions treat engines installed in open-bay vessels (

e.g.

jet boats) and in vessels over 4 meters long as SD/I engines. Finally, the definition in part 91 does not clearly specify how to treat specialty vessels such as airboats or hovercraft that use engines similar to those in conventional SD/I applications. The

definition of personal watercraft grants EPA the discretion to classify engines as SD/I engines if the engine is comparable in technology and emissions to an inboard or sterndrive engine. EPA has used this discretion to classify airboats as SD/I engines. See 40 CFR 91.3 for the existing definitions of the marine engine classes. We continue to believe these engines share fundamental characteristics with traditional SD/I engines and should therefore be treated the same way. However, we believe the definitions should address these applications expressly to make clear which standards apply. We are adopting the following definition:

•

Sterndrive/inboard engine

means a spark-ignition engine that is used to propel a vessel, but is not an outboard engine or a personal watercraft engine. A sterndrive/inboard engine may be either a conventional sterndrive/inboard engine or a high-performance engine. Engines on propeller-driven vessels, jet boats, air boats, and hovercraft are all sterndrive/inboard engines.

SD/I high-performance engines are generally characterized by high-speed operation, supercharged air intake, customized parts, very high power densities, and a short time until rebuild (50 to 200 hours). Based on current SD/I product offerings, we are defining a high-performance engine as an SD/I engine with maximum power above 373 kW (500 hp) that has design features to enhance power output such that the expected operating time until rebuild is substantially shorter than 480 hours.

(2) Exclusions and Exemptions

We are extending our basic nonroad exemptions to the SD/I engines and vessels covered by this rule. These include the testing exemption, the manufacturer-owned exemption, the display exemption, and the national-security exemption. If the conditions for an exemption are met, then the engine is not subject to the exhaust emission standards.

In the rulemaking for recreational vehicles, we chose not to apply standards to hobby products by exempting all reduced-scale models of vehicles that are not capable of transporting a person (67 FR 68242, November 8, 2002). We are extending that same provision to SD/I marine engines (see § 1045.5).

The Clean Air Act provides for different treatment of engines used solely for competition. Rather than relying on engine design features that serve as inherent indicators of dedicated competitive use, as specified in the current regulations, we have taken the approach in more recent programs of more carefully differentiating competition and noncompetition models in ways that reflect the nature of the particular products. In the case of Marine SI engines, we do not believe there are engine design features that allow us to differentiate between engines that are used in high-performance recreational applications and those that are used solely for competition. Starting January 1, 2009, Marine SI engines meeting all the following criteria will therefore be considered to be used solely for competition:

• The engine (or a vessel in which the engine is installed) may not be displayed for sale in any public dealership or otherwise offered for sale to the general public.

• Sale of the vessel in which the engine is installed must be limited to professional racers or other qualified racers.

• The engine must have performance characteristics that are substantially superior to noncompetitive models (

e.g.

higher power-to-weight ratio).

• The engines must be intended for use only in racing events sanctioned (with applicable permits) by the Coast Guard or other public organization, with operation limited to racing events, speed record attempts, and official time trials.

We are also including a provision allowing us to approve an exemption for cases in which an engine manufacturer can provide clear and convincing evidence that an engine will be used solely for competition even though not all the above criteria apply for a given situation. This may occur, for example, if a racing association specifies a particular engine model in their competition rules, where that engine has design features that prevent it from being certified or from being used for purposes other than competition.

Engine manufacturers will make their request for each new model year. We will deny a request for future production if there are indications that some engines covered by previous requests are not being used solely for competition. Competition engines are generally produced and sold in very small quantities, so manufacturers should be able to identify which engines qualify for this exemption. We are applying the same criteria to outboard and personal watercraft engines and vessels. See § 1045.620.

We are adopting a new exemption to address individuals who manufacture recreational marine vessels for personal use (see § 1045.630). Under this exemption, someone may install a used engine in a new vessel where that engine is exempt from standards, subject to certain limitations. For example, an individual may produce one such vessel over a five-year period, the vessel may not be used for commercial purposes, and any exempt engines may not be sold for at least five years. The vessel must generally be built from unassembled components, rather than simply completing assembly of a vessel that is otherwise similar to one that will be certified to meet emission standards. This exemption does not apply for freshly manufactured engines. This exemption addresses the concern that hobbyists who make their own vessels could otherwise be a manufacturer subject to the full set of emission standards by introducing these vessels into commerce. We expect this exemption to involve a very small number of vessels. We revised the provisions of the personal-use exemption since the proposal to allow people to build a vessel with an exempted engine once every five years instead of ten years. We believe this is more reflective of a hobbyists interest in building a boat and using it before moving on to the next building project.

C. Exhaust Emission Standards

We are adopting technology-based exhaust emission standards for new SD/I engines. These standards are similar to the exhaust emission standards that California ARB recently adopted (see Section I). This section describes the provisions related to controlling exhaust emissions from SD/I engines. See Section VI for a description of the new requirements related to evaporative emissions.

(1) Standards and Dates

We are adopting exhaust emission standards of 5.0 g/kW-hr HC+NO

and 75 g/kW-hr CO for SD/I engines, starting with the 2010 model year (see § 1045.105). On average, this represents about a 70 percent reduction in HC+NO

and a 50 percent reduction in CO from baseline engine configurations. Due to the challenges of controlling CO emissions at high load, the expected reduction in CO emissions from low-to mid-power operation is expected to be more than 80 percent. We are providing additional lead time for small businesses as discussed in Section III.F.2. The new standards are based on the same duty cycle that currently is in place for outboard and personal watercraft engines, as described in Section III.D. Section III.G discusses the technological feasibility of these standards in more detail.

The new standards are largely based on the use of small catalytic converters

that can be packaged in the water-cooled exhaust systems typical for these applications. California ARB also adopted an HC+NO

standard of 5 g/kW-hr, starting with 2008 model year engines, but they did not adopt a standard for CO emissions. We believe the type of catalyst used to achieve the HC+NO

standard will also be effective in reducing CO emissions enough to meet the new standard with the proper calibrations, so no additional hardware will be needed to control CO emissions.

Manufacturers have expressed concern that the implementation dates may be difficult to meet, for certain engines, due to anticipated changes in engine block designs produced by General Motors. As described in the Final RIA and in the docket, the vast majority of SD/I engines are based on automotive engine blocks sold by General Motors.

There are five basic engine blocks used, and recently GM announced that it plans to discontinue production of the 4.3L and 8.1L engine blocks. GM anticipates that it will offer a 4.1L engine block and a 6.0L supercharged engine block to the marine industry as replacements. Full-run production of these new blocks is anticipated around the time that manufacturers will be making the transition to meeting new EPA emission standards. SD/I engine manufacturers have expressed concern that they will not be able to begin the engineering processes related to marinizing these engines, including the development of catalyst-equipped exhaust manifolds, until they see the first prototypes of the two replacement engine models. In addition, they are concerned that they do not have enough remaining years of sales of the 4.3L and 8.1L engines to justify the cost of developing catalyst-equipped exhaust manifolds for these engines and amortizing the costs of the required tooling while also developing the two new engine models.

“GM Product Changes Affecting SD/I Engine Marinizers,” memo from Mike Samulski, EPA, to Docket EPA-HQ-OAR-2004-0008-0528.

These are unique circumstances because the SD/I engine manufacturers' plans and products depend on the manufacture of the base engine by a company not directly involved in marine engine manufacturing. The SD/I sales represent only a small fraction of GM's total engine sales and thus did not weigh heavily in their decision to replace the existing engine blocks with two comparable versions during the timeframe when the SD/I manufacturers are facing new emission standards. SD/I manufacturers have stated that alternative engine blocks that meet their needs are not available in the interim, and that it will be cost-prohibitive for them to produce their own engine blocks.

EPA's SD/I standards start to take effect with the 2010 model year, two years after the same standards apply in California. We believe a requirement to extend the California standards nationwide after a two-year delay allows manufacturers adequate time to incorporate catalysts across their product lines as they are doing in California. Once the technology is developed for use in California, it will be available for use nationwide soon thereafter. In fact, one company currently certified to the California standards is already offering catalyst-equipped SD/I engines nationwide. To address the challenge related to the transition away from the current 4.3 and 8.1 liter GM engines, we are including in the final rule a direct approval for a hardship exemption allowing manufacturers to produce these engines for one additional year without certifying them (see § 1045.145). Starting in the 2011 model year, we would expect manufacturers to have worked things out such that they could certify their full product lineup to the applicable standards.

Engines used on jet boats may have been classified under the original definitions as personal watercraft engines. As described in Section IV, engines used in jet boats or personal watercraft-like vessels that are four meters or longer will be classified as SD/I engines under the new definitions. Such engines subject to part 91 today will therefore need to continue meeting EPA emission standards as personal watercraft engines through the 2009 model year under part 91, after which they will need to meet the new SD/I standards under part 1045. This is another situation where the transition period discussed above may be helpful. In contrast, as discussed above, air boats have been classified as SD/I engines under EPA's discretionary authority and are not required to comply with part 91, but must meet the new emission standards for SD/I engines under part 1045.

As described above, engines used solely for competition are not subject to emission standards, but many SD/I high-performance engines are sold for recreational use. SD/I high-performance engines have very high power outputs, large exhaust gas flow rates, and relatively high concentrations of hydrocarbons and carbon monoxide in the exhaust gases. As described in the Final Regulatory Impact Analysis, applying catalyst technology to these engines is not practical. California ARB initially adopted the same HC+NO

standards that apply for other SD/I engines with the expectation that manufacturers would simply rely on emission credits from other SD/I engines. We believe a credit-based solution is not viable for small business manufacturers that do not have other products with which to exchange emission credits and California ARB has modified their rule to also address this concern.

We are adopting standards for SD/I high-performance engines based on the level of control that can be expected from recalibration with electronically controlled fuel injection. These standards are phased in over a two-year transition period. In the 2010 model year, the HC+NO

emission standards are 20.0 g/kW-hr for engines at or below 485 kW and 25.0 g/kW-hr for bigger engines. In 2011 and later model years, the HC+NO

emission standards drop to 16.0 g/kW-hr for engines at or below 485 kW and 22.0 g/kW-hr for bigger engines. The CO standard is 350 g/kW-hr for all SD/I high-performance engines. We believe this is achievable with more careful control of fueling rates, especially under idle conditions. Control of air-fuel ratios should result in improved emission control even after multiple rebuilds. Note that small-volume manufacturers may delay complying with the high-performance standards until 2013. In that year, the standard will be the same as the 2011 standards for larger manufacturers.

We are adopting a variety of provisions to simplify the requirements for exhaust emission certification and compliance for SD/I high-performance engines, as described in Section IV.F. We have also chosen not to apply the Not-to-Exceed emission standards to these engines because we have very limited information on their detailed emission characteristics and we are concerned about extent of testing that would be required by the large number of affected engine manufacturers that are small businesses.

We are also aware that there are some very small sterndrive or inboard engines. In particular, sailboats may have small propulsion engines for backup power. These engines will fall under the new definition of sterndrive/inboard engines, even though they are much smaller and may experience very different in-use operation. These engines generally have more in common with marine auxiliary engines or lawn and garden engines that are subject to land-based standards. We are therefore allowing manufacturers to use engines that have been certified to current land-

based emission standards for sterndrive and inboard installation, much like we are adopting for outboard and personal watercraft engines (see § 1045.610).

The emission standards apply at the range of atmospheric pressures represented by the test conditions specified in part 1065. This includes operation at elevated altitudes. Since we expect most or all SD/I engines to have three-way catalysts with closed-loop fuel control, these engines should be able to include the ability to automatically compensate for varying altitude. Manufacturers may choose to use an altitude kit for demonstrating compliance with emission standards at high altitudes as described for OB/PWC engines in Section IV.C.1. Manufacturers using altitude kits would need to take a variety of steps to describe their approach and ensure that such altitude kits are in fact being used with in-use engines operating at high altitudes, as described in Section IV.E.8.

(2) Not-to-Exceed Standards

We are adopting emission standards that apply over an NTE zone. The NTE standards are in the form of a multiplier times the duty-cycle standard for HC+NO

and for CO (see § 1045.105. Section III.D.2 gives an overview of the NTE standards and compliance provisions and describes the NTE test procedures.

Manufacturers commented that certification to the NTE standards requires additional testing for engine models that are already certified to the new emission standards for California. In addition, they expressed concern that they may need to recalibrate existing engine models to meet the NTE standards. Manufacturers commented that this would not be possible by the date of the duty cycle standard. For engines already certified in California, manufacturers carry over preexisting certification test data from year to year. Manufacturers commented that additional time would be necessary to retest, and potentially recalibrate, these engines for certification to the NTE standards. To address these issues regarding lead time needed to retest these engines, we are not applying the NTE standards for 2010-2012 model year engines that are certified using preexisting data (i.e., carryover engine families). For new engine models, manufacturers indicated that they will be able to perform the NTE testing and duty-cycle testing as part of their efforts to certify to the new standards. Therefore the primary implementation date of 2010 applies to these engines. Beginning in the 2013 model year, all conventional SD/I engines must be certified to meet the NTE standards.

This NTE approach complements the weighted modal emission tests included in this rule. These steady-state duty cycles and standards are intended to establish average emission levels over several discrete modes of engine operation. Because it is an average, manufacturers design their engines with emission levels at individual points varying as needed to maintain maximum engine performance and still meet the engine standard. The NTE limit will be an additional requirement. It is intended to ensure that emission controls function with relative consistency across the full range of expected operating conditions.

(3) Emission Credit Programs

(a) Averaging, Banking, and Trading

We are adopting provisions for averaging, banking, and trading of emission credits for conventional SD/I engines to meet the new HC+NO

and CO standards (see § 1045.105 and part 1045, subpart H). See Section VII.C.5 of the preamble to the proposed rule for a description of general provisions related to averaging, banking, and trading programs. A description of the ABT provisions for the new SD/I standards is provided in this section.

EPA proposed that manufacturers would not be able to earn credits for one pollutant while using credits to comply with the emissions standard for another pollutant. The proposed restriction was modeled on similar requirements in other ABT programs where there was concern that a manufacturer could use technologies to reduce one pollutant while increasing another pollutant. Manufacturers are expected to comply with the new SD/I standards by using a combination of improved engine designs and catalysts. This should result in reductions in both HC+NO

emissions and CO emissions compared to current designs. While the technology is expected to reduce both HC+NO

emissions and CO emissions, there could be situations where the engines are capable of meeting one of the emission standards but not the other. EPA does not want to preclude such engines from being able to certify using the provisions of the ABT program and is therefore dropping the proposed restriction from the final rule.

Credit generation and use is calculated based on the FEL of the engine family and the standard. We are adopting FEL caps to prevent the sale of very high-emitting engines. The HC+NO

FEL cap for conventional SD/I engines is 16 g/kW-hr while the CO FEL cap is 150 g/kW-hr and applies starting in 2010, except as noted below. These FEL caps represent the average baseline emission levels of SD/I engines, based on data described in the Final RIA. However, through the 2013 model year we are separately allowing small-volume engine manufacturers to certify their four-stroke conventional SD/I engines without testing by assuming an HC+NO

FEL of 22.0 g/kW-hr and a CO FEL of 150 g/kW-hr. Manufacturers using this provision would not be subject to the FEL cap for those engine families.

We are specifying that SD/I engines are in a separate averaging set from OB/PWC engines, with a limited exception for certain jet boat engines as described below. This means that credits earned by SD/I engines may be used only to offset higher emissions from other SD/I engines. Likewise, credits earned by OB/PWC engines may be used only to offset higher emissions from other OB/PWC engines (except where we allow those credits to be used for certain jet boat engines).

Emission credits earned for SD/I engines will have an indefinite credit life with no discounting. We consider these emission credits to be part of the overall program for complying with the new standards. Given that we may consider further reductions beyond these standards in the future, we believe it will be important to assess the ABT credit situation that exists at the time any further standards are considered. Emission credit balances will be part of the analysis for determining the appropriate level and timing of new standards, consistent with the statutory requirement to establish standards that represent the greatest degree of emission reduction achievable, considering cost, safety, lead time, and other factors. If we were to allow the use of credits generated under the standards adopted in this rule to meet more stringent standards adopted in a future rulemaking, we may need to adopt emission standards at more stringent levels or with an earlier start date than we would absent the continued use of existing emission credits, depending on the level of emission credit banks. Alternatively, we may adopt future standards without allowing the use of existing emission credits.

Finally, manufacturers may include as part of their federal credit calculation the sales of engines in California as long as they don't separately account for those emission credits under the California regulations. We originally proposed to exclude engines sold in California that are subject to the California ABR standards. However, we

consider California's current HC+NO

standards to be equivalent to those we are adopting in this rulemaking, so we would expect a widespread practice of producing and marketing 50-state products. Therefore, as long as a manufacturer is not generating credits under California's regulations for SD/I engines, we would allow manufacturers to count those engines when calculating credits under EPA's program. This is consistent with how EPA allows credits to be calculated in other nonroad sectors, such as recreational vehicles.

(b) Early-Credit Approaches

We are adopting an early-credit program in which a manufacturer could earn emission credits before 2010 with early introduction of emission controls designed to meet the new standards (see § 1045.145). For engines produced by small-volume SD/I manufacturers that are eligible for the one-year delay described in Section III.F.2, early credits could be earned before 2011. As proposed, use of these early credits would be limited to the first three years that the new standards apply. While we believe adequate lead time is provided to meet the new standards, we recognize that flexibility in timing could help some manufacturers—particularly small manufacturers—to meet the new standards. Other manufacturers that are able to comply early on certain models will be better able to transition their full product line to the new standards by spreading out the transition over two years or more. Under this approach, we anticipate that manufacturers will generate credits through the use of catalysts.

Manufacturers will generate these early credits based on the difference between the measured emission level of the clean engines and an assigned baseline level (16 g/kW-hr HC+NO

and 150 g/kW-hr CO). These assigned baseline levels are based on data presented in Chapter 4 of the Final RIA representing the average level observed for uncontrolled engines. We also provide bonus credits for any small-volume SD/I engine manufacturer that certifies early to the new standards to provide a further incentive for introducing catalysts in SD/I engines. The bonus credits will take the form of a multiplier times the earned credits. The multipliers are 1.25 for being one year early, 1.5 for being two years early, and 2.0 for being three years early. For example, a small-volume manufacturer certifying an engine to 5.0 g/kW-hr HC+NO

in 2009 (two years early) will get a bonus multiplier of 1.5. Early HC+NO

credits will therefore be calculated using the following equation: credits [grams] = (16-5) mu Power [kW] × Useful Life [hours] × Load Factor × 1.5. The specified load factor is 0.207, which is currently used in the OB/PWC calculations.

To earn these early credits, the engine must meet both the new HC+NO

standard and the new CO standard. These early credits will be treated the same as emission credits generated after the emission standards start to apply. This approach provides an incentive for manufacturers to pull ahead significantly cleaner technologies. We believe such an incentive will lead to early introduction of catalysts on SD/I engines and help promote earlier market acceptance of this technology. We believe this early credit program will allow manufactures to comply with the new standards in an earlier time frame because it allows them to spread out their development resources over multiple years. To ensure that manufacturers do not generate credits for meeting standards that already apply, no EPA credits will be generated for engines that are produced for sale in California.

Sterndrive and inboard vessels are typically propelled by traditional SD/I engines based on automotive engine blocks. As explained in Section IV, we are changing the definition of personal watercraft to ensure that engines used on jet boats will no longer be classified as personal watercraft engines but instead as SD/I engines because jet boats are more like SD/I vessels. However, manufacturers in many cases make these jet boats by installing an engine also used in outboard or personal watercraft applications (less than 4 meters in length) and coupling the engine to a jet drive for propelling the jet boat. Thus, manufacturers of outboard or personal watercraft engines may also manufacture the same or a similar engine for use on what we consider to be a jet boat.

Engines used in jet boats will be subject to SD/I emission standards. However, we are providing some flexibility in meeting the new emission standards for jet boat engines because they are currently designed to use engines derived from OB/PWC applications and because of their relatively low sales volumes. We will allow manufacturers to use emission credits generated from OB/PWC engines to demonstrate that their jet boat engines meet the new HC+NO

and CO standards for SD/I engines if the same or similar engine is certified as an outboard or personal watercraft engine, and if the majority of units sold in the United States from those related engine families are sold for use as outboard or personal watercraft engines (see § 1045.660 and § 1045.701). Manufacturers will need to group SD/I engines used for jet boats in a separate engine family from the outboard or personal watercraft engines to ensure proper labeling and calculation of emission credits, but manufacturers could rely on emission data from the same prototype engine for certifying both engine families.

Finally, manufacturers of jet boat engines subject to SD/I standards and using credits from outboard or personal watercraft engines must certify these jet boat engines to an FEL that meets or exceeds the newly adopted standards for outboard and personal watercraft engines. This limits the degree to which manufacturers may take advantage of emission credits to produce engines that are emitting at higher levels than competitive engines.

(d) SD/I High-Performance Engines

For the reasons described in Section III.C.1, the standards being adopted for SD/I high-performance engines are less stringent than originally proposed. As a result, we are not including the SD/I high-performance engines in the ABT program. Manufacturers are required to meet the emission standards for SD/I high-performance engines without using emission credits.

(4) Crankcase Emissions

Due to blowby of combustion gases and the reciprocating action of the piston, exhaust emissions can accumulate in the crankcase. Uncontrolled engine designs route these vapors directly to the atmosphere. Closed crankcases have become standard technology for automotive engines and for outboard and personal watercraft engines. Manufacturers generally do this by routing crankcase vapors through a valve into the engine's air intake system. We are requiring manufacturers to prevent crankcase emissions from SD/I marine engines (see § 1045.115). Because automotive engine blocks are already tooled for closed crankcases, the cost of adding a valve for positive crankcase ventilation is small for SD/I engines. Even with non-automotive blocks, the tooling changes necessary for closing the crankcase are straightforward.

(5) Durability Provisions

We rely on pre-production certification, and other programs, to ensure that engines control emissions throughout their intended lifetime of operation. Section VII of the preamble to

the proposed rule describes how we require manufacturers to incorporate laboratory aging in the certification process, how we limit the extent of maintenance that manufacturers may specify to keep engines operating as designed, and other general provisions related to certification. The following sections describe additional provisions that are specific to SD/I engines.

(a) Useful Life

We are specifying a useful life period of ten years or 480 hours of engine operation, whichever comes first (see § 1045.105). Manufacturers are responsible for meeting emission standards during this useful life period. This is consistent with the requirements adopted by California ARB. We are further requiring that the 480-hour useful life period is a baseline value, which may be extended if data show that the average service life for engines in the family is longer. For example, we may require that the manufacturer certify the engine over a longer useful life period that more accurately represents the engines' expected operating life if we find that in-use engines are typically operating substantially more than 480 hours. This approach is similar to what we adopted for recreational vehicles.

For SD/I high-performance engines, we are specifying a useful life of 150 hours or 3 years for engines at or below 485 kW and a useful life of 50 hours or 1 year for engines above 485 kW. Due to the high power and high speed of these engines, mechanical parts are often expected to wear out quickly. For instance, one manufacturer indicated that some engines above 485 kW have scheduled head rebuilds between 50 and 75 hours of operation. These useful life values are consistent with the California ARB regulations for SD/I high-performance engines.

Some SD/I engines below 373 kW may be designed for high power output even though they do not reach the power threshold to qualify as SD/I high-performance engines. Because they do not qualify for the shorter useful life that applies to SD/I high-performance engines, they will be subject to the default value of 480 hours for other SD/I engines. However, to address the limited operating life for engines that are designed for especially high power output, we are allowing manufacturers to request a shorter useful life for such an engine family based on information showing that engines in the family rarely operate beyond the requested shorter period. For example, if engines designed for extremely high-performance are typically rebuilt after 250 hours of operation, this will form the basis for establishing a shorter useful life period for those engines. See § 1045.105 for additional detail in establishing a shorter useful life.

Jet boat engines that are certified in conjunction with outboard or personal watercraft engine families are subject to the shorter useful life period that applies for outboard or personal watercraft engines. This is necessary to prevent a situation where the original certification data is insufficient for certifying the jet boat engines without some further testing or analysis to show that the engines meet emission standards over a longer period.

(b) Warranty Periods

We are requiring that manufacturers provide an emission-related warranty during the first three years or 480 hours of engine operation, whichever comes first (see § 1045.120). This warranty period applies equally to emission-related electronic components on SD/I high-performance engines. However, we are allowing shorter warranty periods (in hours) for emission-related mechanical components on SD/I high-performance engines because these parts are expected to wear out more rapidly than comparable parts on traditional SD/I engines. Specifically, we are specifying a warranty period for emission-related mechanical components of 3 years or 150 hours for high-performance engines between 373 and 485 kW, and 1 year or 50 hours for high-performance engines above 485 kW. These warranty periods are the same as those adopted by the California ARB.

If the manufacturer offers a longer warranty for the engine or any of its components at no additional charge, we require that the emission-related warranty for the respective engine or component must be extended by the same amount. The emission-related warranty includes components related to controlling exhaust, evaporative, and crankcase emissions from the engine. These warranty requirements are consistent with provisions that apply in most other programs for nonroad engines.

(6) Engine Diagnostics

We are requiring that manufacturers design their catalyst-equipped SD/I engines to diagnose malfunctioning emission control systems starting with the introduction of the final standards (see § 1045.110). As discussed in the Final RIA, three-way catalyst systems with closed-loop fueling control work well only when the air-fuel ratios are controlled to stay within a narrow range around stoichiometry. Worn or broken components or drifting calibrations over time can prevent an engine from operating within the specified range. This increases emissions and can lead to significantly increased fuel consumption and engine wear. The operator may or may not notice the change in the way the engine operates. We are not requiring similar diagnostic controls for OB/PWC engines because the anticipated emission control technologies for these other applications are generally less susceptible to drift and gradual deterioration. We have adopted similar diagnostic requirements for Large SI engines operating in forklifts and other industrial equipment that also use three-way catalysts to meet emission standards.

This diagnostic requirement focuses solely on maintaining stoichiometric control of air-fuel ratios. This kind of design detects problems such as broken oxygen sensors, leaking exhaust pipes (upstream of sensors and catalysts), fuel deposits, and other things that require maintenance to keep the engine at the proper air-fuel ratio.

Diagnostic monitoring provides a mechanism to help keep engines tuned to operate properly, with benefits for both controlling emissions and maintaining optimal performance. There are currently no inspection and maintenance programs for marine engines, so the most important variable in making the emission control and diagnostic systems effective is getting operators to repair the engine when the diagnostic light comes on. This calls for a relatively simple design to avoid signaling false failures as much as possible. The diagnostic requirements in this final rule, therefore, focus on detecting inappropriate air-fuel ratios, which is the most likely failure mode for three-way catalyst systems. The malfunction indicator must go on when an engine runs for a full minute under closed-loop operation without reaching a stoichiometric air-fuel ratio.

California ARB has adopted diagnostic requirements for SD/I engines that involve a more extensive system for monitoring catalyst performance and other parameters. We will accept a California-approved system as meeting EPA requirements. The final regulations direct manufacturers to follow standard practices defined in documents adopted recently by the Society of Automotive Engineers in SAE J1939-5. See § 1045.110 for detailed information.

D. Test Procedures for Certification

(1) General Provisions

The marine engine test procedures are generally the same for both SD/I and OB/PWC engines. This involves laboratory measurement of emissions while the engine operates over the ISO E4 duty cycle. This is a five-mode steady-state duty cycle including an idle mode and four modes lying on a propeller curve with an exponent of 2.5, as shown in Appendix II to part 1045. The International Organization for Standardization (ISO) intended for this cycle to be used for recreational spark-ignition marine engines installed in vessels up to 24 m in length. Because most or all vessels over 24 m have diesel engines, we believe the E4 duty cycle is most appropriate for SD/I engines covered by this rule. There may be some spark-ignition engines installed in vessels somewhat longer than 24 m, but we believe the E4 duty cycle is no less appropriate in these cases. See Section IV.D for a discussion of adjustments to the test procedures related to the migration to 40 CFR part 1065, testing with a ramped-modal cycle, determining maximum test speed for denormalizing the duty cycle, and testing at high altitude.

The E4 duty cycle includes a weighting of 40 percent for idle. For SD/I high-performance engines, commenters suggested that these engines typically have substantial auxiliary loads and parasitic losses even when the vessel does not need propulsion power. While the specified duty cycle for SD/I high-performance engines is identical to that for other Marine SI engines, we would expect manufacturers to use the provisions of § 1065.510(b)(3) to target a reference torque of 15 percent instead of zero at idle.

(2) Not-to-Exceed Test Procedures and Standards

We are adopting not-to-exceed (NTE) requirements similar to those established for marine diesel engines. Engines will be required to meet the NTE standards during normal in-use operation.

(a) Concept

Our goal is to achieve control of emissions over a wide range of ambient conditions and over the broad range of in-use speed and load combinations that can occur on a marine engine. This will ensure real-world emission control, rather than just controlling emissions under certain laboratory conditions. This allows us to evaluate an engine's compliance during in-use testing without removing the engine from the vessel because the NTE requirements establish an objective standard and an easily implemented test procedure. Our traditional approach has been to set a numerical standard on a specified test procedure and rely on the additional prohibition of defeat devices to ensure in-use control over a broad range of operation not included in the test procedure. We are establishing the same prohibition on defeat devices for OB/PWC and SD/I engines (see § 1045.115).

No single test procedure or test cycle can cover all real-world applications, operations, or conditions. Yet to ensure that emission standards are providing the intended benefits in use, we must have a reasonable expectation that emissions under real-world conditions reflect those measured on the test procedure. The defeat device prohibition is designed to ensure that emission controls are employed during real-world operation, not just under laboratory testing conditions. However, the defeat device prohibition is not a quantified standard and does not have an associated test procedure, so it does not have the clear objectivity and ready enforceability of a numerical standard and test procedure. We believe using the traditional approach, i.e., using only a standardized laboratory test procedure and test cycle, makes it difficult to ensure that engines will operate with the same level of emission control in use as in the laboratory.

Because the duty cycle we have adopted uses only five modes on an average propeller curve to characterize marine engine operation, we are concerned that an engine designed to that duty cycle will not necessarily perform the same way over the range of speed and load combinations seen on a boat. This duty cycle is based on an average propeller curve, but a marine propulsion engine may never be fitted with an “average propeller.” For instance, an engine installed in a specific boat with a particular propeller may operate differently based on the design of the boat and how heavily the boat is loaded, among other factors.

To ensure that engines control emissions over a wide range of speed and load combinations normally seen on boats, we are including a zone under the engine's power curve where the engine may not exceed a specified emission limit (see § 1045.105 and § 1045.515). This limit will apply to all regulated pollutants during steady-state operation. In addition, we are requiring that a wide range of real ambient conditions be included in testing with this NTE zone. The NTE zone, limit, and ambient conditions are described below.

We believe there are significant advantages to establishing NTE standards. The final NTE test procedure is flexible, so it can represent the majority of in-use engine operation and ambient conditions. The NTE approach thus takes all the benefits of a numerical standard and test procedure and expands it to cover a broad range of conditions. Also, laboratory testing makes it harder to perform in-use testing because either the engines will have to be removed from the vessel or care will have to be taken to achieve laboratory-type conditions on the vessel. With the NTE approach, in-use testing and compliance become much easier since emissions may be sampled during normal boating. By establishing an objective measurement, this approach makes enforcement of defeat device provisions easier and provides more certainty to the industry.

Even with the NTE requirements, we believe it is still appropriate to retain standards based on the steady-state duty cycle. This is the standard that we expect the certified marine engines to meet on average in use. The NTE testing is focused more on maximum emissions for segments of operation and, in most cases, will not require additional technology beyond what is used to meet the final standards. In some cases, the calibration of the engine may need to be adjusted. We believe that basing the emission standards on a distinct cycle and using the NTE zone to ensure in-use control creates a comprehensive program.

We believe the technology used to meet the standards over the five-mode duty cycle, when properly calibrated, will meet the caps that apply across the NTE zone. We therefore do not expect the final NTE standards to cause manufacturers to need additional hardware. We believe the NTE standard will not result in a large amount of additional testing, because these engines should be designed to perform as well in use as they do over the five-mode test. However, our cost analysis in the Final RIA accounts for some additional testing, especially in the early years, to provide manufacturers with assurance that their engines will meet the NTE requirements.

(b) Shape of NTE Zone

We developed the NTE zone based on t

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