[Federal Register Volume 77, Number 111 (Friday, June 8, 2012)]
[Rules and Regulations]
[Pages 34130-34148]
[FR Doc No: 2012-13088]

Vol. 77

Friday,

No. 111

June 8, 2012

Part II

Environmental Protection Agency

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40 CFR Parts 85, 86, and 1039

 Heavy-Duty Highway Program: Revisions for Emergency Vehicles and SCR
Maintenance; Final Rule and Proposed Rule

Federal Register / Vol. 77 , No. 111 / Friday, June 8, 2012 / Rules
and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 85, 86, and 1039

[EPA-HQ-OAR-2011-1032; FRL-9673-1]
RIN 2060-AR54

Heavy-Duty Highway Program: Revisions for Emergency Vehicles

AGENCY:  Environmental Protection Agency (EPA).

ACTION: Direct final rule.

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SUMMARY:  EPA is taking direct final action on revisions to its heavy-
duty diesel regulations that will enable emergency vehicles, such as
dedicated ambulances and fire trucks, to perform mission-critical life-
saving work without risking that abnormal conditions of the emission
control system could lead to decreased engine power, speed or torque.
The revisions will allow manufacturers to request and EPA to approve
modifications to emission control systems on emergency vehicles so they
do not interfere with the vehicles' missions. This action is not
expected to result in any significant changes in regulatory burdens or
costs.

DATES: This rule is effective on August 7, 2012 without further notice,
unless EPA receives adverse comment. If we receive relevant adverse
comment on distinct elements of this rule by July 27, 2012, we will
publish a timely withdrawal in the Federal Register indicating which
provisions we are withdrawing. The provisions that are not withdrawn
will become effective on August 7, 2012, notwithstanding adverse
comment on any other provision.

ADDRESSES:  Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2011-1032, by one of the following methods:
     www.regulations.gov: Follow the on-line instructions for
submitting comments.
     Email<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER>
     Mail: Environmental Protection Agency, Air Docket, Mail-
code 6102T, 1200 Pennsylvania Ave. NW., Washington, DC 20460.
     Hand Delivery: EPA Docket Center (EPA/DC), EPA West, Room
3334, 1301 Constitution Ave. NW., Washington, DC, Attention Docket No.
EPA-HQ-OAR-2010-0162. Such deliveries are only accepted during the
Docket's normal hours of operation, and special arrangements should be
made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2011-1032. For additional instructions on submitting written comments,
see the SUPPLEMENTARY INFORMATION section on ``Public Participation''
in the parallel Notice of Proposed Rulemaking in today's Federal
Register.
    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, e.g., 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 EPA Docket Center, EPA/DC,
EPA West, Room 3334, 1301 Constitution Ave. NW., Washington, DC. The
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is<PHONE_NUMBER>, and the telephone number for the Air
Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT:  Lauren Steele, Environmental
Protection Agency, Office of Transportation and Air Quality, Assessment
and Standards Division, 2000 Traverwood Drive, Ann Arbor, Michigan
48105; telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>; email
address: steele.lauren (@epa.gov).

SUPPLEMENTARY INFORMATION:

Why is EPA using a direct final rule?

    EPA is publishing this rule without a prior proposed rule because
we view this as a noncontroversial action and anticipate no adverse
comment. This is also to expedite the regulatory process to allow
engine and vehicle modifications to occur as soon as possible. However,
in the ``Proposed Rules'' section of today's Federal Register, we are
publishing a separate document that will serve as the proposed rule to
adopt these revisions for emergency vehicles if adverse comments are
received on this direct final rule. We will not institute a second
comment period on this action. Any parties interested in commenting
must do so at this time. For further information about commenting on
this rule, see the ADDRESSES section of this document.
    If EPA receives adverse comment on a distinct provision of this
rulemaking, we will publish a timely withdrawal in the Federal Register
indicating which provisions we are withdrawing. The provisions that are
not withdrawn will become effective on the date set out above,
notwithstanding adverse comment on any other provision. We would
address all public comments in a subsequent final rule based on the
proposed rule.
    EPA is publishing this direct final rule to expedite the deployment
of solutions that will best ensure the readiness of the nation's
emergency vehicles. We request that commenters identify in your
comments any portions of the action with which you agree and support as
written, in addition to any comments regarding suggestions for
improvement or provisions with which you disagree. In the case of a
comment that is otherwise unclear whether it is adverse, EPA would
interpret relevant comments calling for more flexibility or less
restrictions for emergency vehicles as supportive of the direct final
action. In this way, the EPA will be able to adopt those elements of
this action that are fully supported and most needed today, while
considering and addressing any adverse comments received on the
proposed rule, in the course of developing the final rule.

Does this action apply to me?

    This action may affect you if you produce or import new heavy-duty
or nonroad diesel engines that are intended for use in vehicles that
serve the emergency response industry, including all types of dedicated
and purpose-built fire trucks and ambulances. The following table gives
some examples of entities that may be affected by this action. Because
these are only examples, you should carefully examine the existing and
revised regulations in 40 CFR parts 85, 86 and 1039. If you have
questions regarding how or whether these rules apply to you, you may
call the person listed in the FOR FURTHER INFORMATION CONTACT section
above.

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                                                 Examples of potentially
            Category             NAICS code \a\     affected entities
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Industry.......................          336111  Motor Vehicle
                                                  Manufacturers, Engine
                                                  and Truck
                                                  Manufacturers.
                                         336112
                                         333618
                                         336120

Industry.......................          541514  Commercial Importers of
                                                  Vehicles and Vehicle
                                                  Components.
                                         811112
                                         811198
Industry.......................          811310  Engine Repair,
                                                  Remanufacture, and
                                                  Maintenance.
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Note:
\a\ North American Industry Classification System (NAICS).

Table of Contents

I. Overview
II. Statutory Authority and Regulatory Background
    A. Statutory Authority
    B. Background: 2007 and 2010 NOX and PM Standards
    (1) On-Highway Standards
    (2) Nonroad Standards
III. Emergency Vehicle Provisions
    A. Background on Regulation of Emergency Vehicles
    B. Why is EPA taking this action?
    (1) How does a DPF work?
    (2) Why are emergency vehicles having problems with DPF
regeneration?
    (3) What are the concerns for emergency vehicles using SCR?
    C. What would occur if EPA took no action?
    (1) The Industry Would Continue To Get Smarter
    (2) The Fleet Would Continue To Migrate to the 2010 Standards
    (3) Some Trucks Would Continue To Experience Problems
    D. Regulatory Action
    (1) Liberalized Regeneration Requests
    (2) Engine Recalibration
    (3) Backpressure Relief
    E. What engines and vehicles are affected?
    (1) Newly Certified Engines
    (2) Certified Engines and Vehicles In-Use
    (3) Labeling Requirements
    (4) Other Regulatory Provisions
    F. Economic Impacts
    (1) Costs to Manufacturers
    (2) Operational Costs
    (3) Societal Costs
    G. Environmental Impacts
    H. Health Effects
IV. 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 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Congressional Review Act

I. Overview

    EPA is adopting amendments to its heavy-duty diesel engine programs
that will specifically allow engine manufacturers to request to deploy
specific emission controls or settings for new and in-use engines that
are sold for use only in emergency vehicles. EPA is adopting these
revisions to enable fire trucks and ambulances with heavy-duty diesel
engines to perform mission-critical life- and property-saving work
without risk of losing power, speed or torque due to abnormal
conditions of the emission control systems.
    EPA's current diesel engine requirements have spurred application
of emission controls systems such as diesel particulate filters
(commonly called soot filters or DPF's) and other after-treatment
systems on most new diesel vehicles, including emergency vehicles. Some
control system designs and implementation strategies are more effective
in other segments of the fleet than in emergency vehicles, especially
given some emergency vehicles' extreme duty cycles. By this action, EPA
intends to help our nation's emergency vehicles perform their missions;
to better ensure public safety and welfare and the protection of lives
and property.

II. Statutory Authority and Regulatory Background

A. Statutory Authority

    Section 202(a)(1) of the Clean Air Act (CAA or the Act) directs EPA
to establish standards regulating the emission of any air pollutant
from any class or classes of new motor vehicles or new motor vehicle
engines that, in the Administrator's judgment, causes or contributes to
air pollution which may reasonably be anticipated to endanger public
health or welfare. Such standards apply for the useful life of the
vehicles or engines. Section 202(a)(3) requires that EPA set standards
applicable to emissions of hydrocarbons, carbon monoxide,
NOX and particulate matter (PM) from heavy-duty trucks that
reflect the greatest degree of emission reduction achievable through
the application of technology which we determine will be available for
the model year to which the standards apply. We are to give appropriate
consideration to cost, energy, and safety factors associated with the
application of such technology. We may revise such technology-based
standards, taking costs into account, on the basis of information
concerning the effects of air pollution from heavy-duty vehicles or
engines and other sources of mobile source related pollutants on the
public health and welfare.
    Section 202(a)(4)(A) of the Act requires the Administrator to
consider risks to public health, welfare or safety in determining
whether an emission control device, system or element of design shall
be used in a new motor vehicle or new motor vehicle engine. Under
section 202(a)(4)(B), the Administrator shall consider available
methods for reducing risk to public health, welfare or safety
associated with use of such device, system or element of design, as
well as the availability of other devices, systems or elements of
design which may be used to conform to requirements prescribed by (this
subchapter) without causing or contributing to such unreasonable risk.
    Section 206(a) of the Act requires EPA to test, or require to be
tested in such manner as it deems appropriate, motor vehicles or motor
vehicle engines submitted by a manufacturer to determine whether such
vehicle or engine conforms to the regulations promulgated under section
202. Section 206(d) provides that EPA shall by regulation establish
methods and procedures for making tests under section 206.
    Section 213 of the Act gives EPA the authority to establish
emissions standards for nonroad engines and vehicles (42 U.S.C. 7547).
Sections 213(a)(3) and (a)(4) authorize the Administrator to set
standards and require EPA to give appropriate consideration to cost,
lead time, noise, energy, and safety factors associated with the
application of technology. Section 213(a)(4) authorizes the
Administrator to establish standards to control emissions of pollutants
(other than those covered by section 213(a)(3)) which ``may reasonably
be anticipated to endanger public health and welfare.'' Section 213(d)
requires the standards under section 213 to be subject to sections 206-
209 of the Act and to be

enforced in the same manner as standards prescribed under section 202
of the Act.

B. Background: 2007 and 2010 NOX and PM Standards

(1) On-Highway Standards
    On January 18, 2001, EPA published a rule promulgating more
stringent standards for NOX and PM for heavy-duty highway
engines (``the heavy-duty highway rule'').\1\ The 0.20 gram per brake-
horsepower-hour (g/bhp-hr) NOX standard in the heavy-duty
highway rule first applied in MY 2007. However, because of phase-in
flexibility provisions adopted in that rule and use of emission credits
generated by manufacturers for early compliance, manufacturers were
able to continue to produce engines with NOX emissions
greater than 0.20 g/bhp-hr. The phase-in provisions ended after MY 2009
so that the 0.20 g/bhp-hr NOX standard was fully phased-in
for model year 2010. Because of these changes that occurred in MY 2010,
the 0.20 g/bhp-hr NOX emission standard is often referred to
as the 2010 NOX emission standard, even though it applied to
engines as early as MY 2007.
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    \1\ Control of Air Pollution from New Motor Vehicles: Heavy-Duty
Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control
Requirements (66 FR 5001).
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    The heavy-duty highway rule adopted in 2001 also included a PM
emissions standard for new heavy-duty diesel engines of 0.01 g/bhp-hr,
effective for engines beginning with MY 2007. Due to the flexible
nature of the phase-in schedule described above, manufacturers have had
the opportunity to produce engines that met the PM standard while
emitting higher levels of NOX. During the phase-in years,
manufacturers of diesel engines generally produced engines that were
tuned so the combustion process inherently emitted lower engine-out
NOX while relying on PM after-treatment to meet the PM
standard. The principles of combustion chemistry dictate that
conditions yielding lower engine-out NOX emissions generally
result in higher engine-out PM emissions. This is what we call the
NOX-PM trade-off. For many new low-NOX diesel
engines today, engine-out PM emissions could be at or above the levels
seen with the MY 2004 standards (0.1 g/bhp-hr). To meet today's
stringent PM standards, manufacturers rely on diesel particulate filter
after-treatment to clean the exhaust.
(2) Nonroad Standards
    EPA adopted similar technology-forcing standards for nonroad diesel
engines on June 29, 2004.\2\ These are known as the Tier 4 standards.
This program includes requirements that will generally involve the use
of NOX after-treatment for engines above 75 hp and PM after-
treatment (likely soot filters) for engines above 25 hp. These
standards phase in during the 2011 to 2015 time frame.
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    \2\ Control of Emissions of Air Pollution from Nonroad Diesel
Engines and Fuel (69 FR 38958).
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III. Emergency Vehicle Provisions

A. Background on Regulation of Emergency Vehicles

    Typically, the engines powering our nation's emergency vehicles
belong to the same certified engine families as engines that are
installed in similarly sized vehicles sold for other public and private
uses.\3\ Historically, engine and vehicle manufacturers have sought EPA
certification for broad engine families and vehicle test groups that
are defined by similar emissions and performance characteristics.
Engine families typically only consider the type of vehicle in which
the engine is intended to be installed to the extent that it fits into
a broad vehicle weight class and, to a lesser extent, the vehicle's
intended duty cycle (i.e. urban or highway).
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    \3\ In this rule, emergency vehicle is defined as a fire truck
or an ambulance for on-highway applications, and for nonroad
applications, we are defining emergency equipment as specialized
vehicles to perform aircraft rescue and firefighting functions at
airports, or wildland fire apparatus. See Section III.C and
revisions at 40 CFR 86.1803-01 and 40 CFR 1039.801.
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    Because of the above-described manufacturing practices and the
narrow CAA authority for any exemptions, EPA has historically regulated
engines for emergency vehicles, including ambulances as well as police
vehicles and fire-fighting apparatus, in the same manner as other
engines.
    In the public comments received on the proposed heavy-duty highway
rule, EPA received some comments about DPF technologies and
regeneration cycles on heavy-duty trucks, including one comment that
expressed concerns that the systems may not be failsafe.\4\ However,
none of the comments specifically raised technical feasibility with
respect to emergency vehicles, and EPA's response was based on the best
information available at the time. After publishing the final rule
requiring heavy-duty highway engines to meet performance standards that
compelled technologies such as DPF's, EPA received a letter from the
National Association of State Fire Marshals, requesting some provision
for public safety in implementing this new rule, considering that fire
departments across the nation have trouble covering basic costs and may
not have funds for more expensive trucks.\5\ This letter did not raise
any technical feasibility issues, and EPA did not see a need to take
action.
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    \4\ Heavy-Duty Highway Final Rule, December 21, 2000, Response
to Comments, Section 3.2.1, ``Technical Feasibility of Engine/
Vehicle Standards//Diesel Engine Exhaust Standards,'' page 3-58 to
3-60, available at http://www.epa.gov/otaq/highway-diesel/regs/2007-heavy-duty-highway.htm.
    \5\ Letter dated February 1, 2001 to C. Whitman, EPA
Administrator from G. Miller, President, National Association of
State Fire Marshalls.
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    More recently EPA has received letters from fire apparatus
manufacturers and ambulance companies requesting relief from power or
speed inducements related to low levels of DEF for SCR systems on
emergency vehicles.\6\ Power and speed reduction inducements were new
on vehicles equipped with SCR. These were not specifically mandated by
EPA but designed by manufacturers to occur if DEF levels became low, to
induce operators of the vehicles to perform the required emission-
related maintenance in use. More discussion on this, including why the
emergency response community requested relief and what action EPA took,
is found below in Section III.B(3).
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    \6\ See, for example, letter dated October 22, 2009, from Roger
Lackore of the Fire Apparatus Manufacturers' Association and Randy
Hanson of the Ambulance Manufacturers Division, to Keisha Jennings
of EPA.
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    Recently, beginning in October 2011, EPA received a series of
comment letters from fire chiefs and other interested stakeholders,
requesting regulatory action to relieve emergency vehicles from the
burden of complying with the 2007 PM standards.\7\ EPA promptly opened
a dialogue with the fire chiefs and engine manufacturers to understand
the issues. Power and speed reductions were occurring on some vehicles
with soot filters but without SCR systems, in part related to engine
protection measures designed by manufacturers. Essentially, these soot
filters are supposed to be self-cleaning by periodically burning off
accumulated soot during normal vehicle use. The cleaning process is
called regeneration, and when this doesn't work as designed, the filter
gradually gets more clogged, which can lead to engine problems. EPA has
determined that while other

pathways are available for resolving some issues related to soot
filters on emergency vehicles, there remains a public safety issue
related to design of engines and emission control systems on emergency
vehicles that should be addressed through this rulemaking. More
discussion of this, including why relief was requested and what other
actions can be taken in addition to EPA regulation, is found below in
Sections III.B and III.C.
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    \7\ See, for example, letter dated October 4, 2011 from
Congressman Filner to EPA Administrator Jackson, and letter dated
October 14, 2011, from Director Cimini of the Southeast Association
of Fire Chiefs to EPA Administrator Jackson.
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    There have been some examples of EPA providing limited exemptions
for other types of emergency-use engines and vessels. Further
descriptions of current and proposed limited exemptions are provided in
the Notice of Proposed Rulemaking published elsewhere in today's
Federal Register. These limited exemption provisions are only
applicable to newly certified engines. They are not applicable to any
existing in-use engines that are already deployed in emergency
equipment.

B. Why is EPA taking this action?

    EPA is amending its regulations to facilitate engine manufacturers'
design and implementation of reliable and robust emission control
systems with regeneration strategies and other features that do not
interfere with the mission of emergency vehicles. Through the comments
and letters we have received, as well as our own outreach and data-
gathering efforts, we have learned that some emission control systems
on fire trucks and ambulances today, in particular, certain
applications using diesel particulate filters, are requiring an
unexpected amount of operator interventions, and there are currently a
nontrivial number of emergency vehicles that are electronically
programmed to cut power or speed--even while responding to an
emergency--when certain operational parameters are exceeded in relation
to the emission control system. As we understand it, the experiences of
operators are mixed, with some not reporting any problems and some
reporting problems that raise public safety and welfare concerns.
    EPA's standards are performance-based, and reflect the greatest
degree of emission reduction achievable, according to CAA sections
202(a)(3) and 213(a)(3). Our on-highway and nonroad PM standards do not
specify the type of diesel particulate filter for manufacturers to use,
nor do they even mandate the use of such a filter. Our analysis of the
feasibility of the 2007 on-highway PM standard is presented in Chapter
III of the final Regulatory Impact Analysis (RIA) for that rule.\8\ Our
analysis of the feasibility of the Tier 4 nonroad compression ignition
engine standards that will be phasing in through 2015 is presented in
Chapter 4 of that rule's final RIA.\9\ For most nonroad engines, these
standards are similar in stringency to the 2007 on-highway heavy-duty
engine and vehicle standards. As described below in Section III.H,
these two rules are providing billions of dollars of annual health
benefits by virtually eliminating harmful PM emissions from the
regulated engines. Even so, EPA is required by sections 202(a)(4)(B)
and 213(c) of the Act to, among other things, consider methods for
reducing risk to public safety and welfare associated with the use of
emission control devices or systems.
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    \8\ Final Regulatory Impact Analysis for the ``2007 Heavy-Duty
Highway Rule,'' EPA420-R-00-026, December 2000. Chapter III,
Emissions Standards Feasibility, is available at http://www.epa.gov/otaq/highway-diesel/regs/ria-iii.pdf.
    \9\ Final Regulatory Impact Analysis for ``Control of Emissions
from Nonroad Diesel Engines,'' EPA420-R-04-007, May 2004. Chapter 4,
Technologies and Test Procedures for Low-Emission Engines, is
available http://www.epa.gov/nonroad-diesel/2004fr/420r04007e.pdf.
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    Based on the information available to us, we have concluded that
there is an indirect risk to public safety and welfare associated with
some examples of emission control systems when they are deployed on
emergency vehicles that experience extreme duty cycles. This indirect
risk is related to the readiness of emergency vehicles and the risk
that they may not be able to respond during emergencies with the full
power, torque, or speed that the engine is designed to provide. While
this risk is not inherent to the requirement to reduce emissions or to
the use of diesel particulate filters on emergency vehicles, EPA
believes it is appropriate to ensure that emergency vehicles can
perform their emergency missions without the chance of such
consequences.
    EPA's current rules already provide the opportunity for
manufacturers to address many issues through applications for
certification of new engines and new vehicles. There is also currently
a mechanism for manufacturers to deploy field modifications to the in-
use fleet, including those that are substantially similar to approved
upgrades for new vehicles, as well as those that apply only to vehicles
that are no longer in production. As manufacturers become aware of the
need for upgrades or enhancements, this process occurs within the new
and in-use fleet with various degrees of application. While that
process is occurring today, EPA views this issue as serious enough that
we would be remiss if we did not act to ensure that our regulations
clearly offer the needed flexibilities for emergency vehicles.
(1) How does a DPF work?
    To explain more fully the issues that we are addressing with this
action, and hence why we are taking this action, we are providing here
some background information on diesel particulate filters and the
process of DPF regeneration. DPF's are exhaust after-treatment devices
that significantly reduce emissions from diesel-fueled vehicles and
equipment. DPF's physically trap PM and remove it from the exhaust
stream. Figure III-1 depicts a schematic of a wall-flow monolith style
filter, with the black arrows indicating exhaust gas laden with
particles, and the gray arrows indicating filtered exhaust gas. This
style of filter is the most common in today's heavy-duty diesel
engines, and has very high rates of filtration, in excess of 95
percent.\10\
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    \10\ See Final RIA Chapter III, Note 8, above.

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[GRAPHIC] [TIFF OMITTED] TR08JN12.000

    To be successful, these devices generally must be able to
accomplish two things: Collect PM and clean away accumulated PM. There
are two main types of PM that can accumulate: combustible and non-
combustible, and two very different types of cleaning methods:
regeneration and ash cleaning. Regeneration occurs relatively
frequently, and is designed to complete the combustion (oxidation) of
the trapped combustible PM components, releasing them to the exhaust as
gas-phase compounds (mostly H2O and CO2). In
contrast to the PM that can be oxidized and carried out the tailpipe as
gases, the non-combustible PM such as metallic ash cannot be destroyed
through regeneration and will always remain inside a DPF. To clean ash
from a DPF, the filter unit is removed from the vehicle and
professionally cleaned with a special machine. Fortunately, there is
very little ash formation from modern diesels so ash cleaning and ash
disposal occurs very infrequently, generally with at least 150,000 mile
service intervals, and the mass of accumulated ash is generally small
(a few teaspoons).11 12 This distinction is made here
because the ash cleaning process is not a source of concern that has
given rise to this EPA action. The infrequent cleaning of
noncombustible materials from DPF's is not part of the scope of this
action.
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    \11\ EPA's regulations at 40 CFR 86.004-25(b)(4) for heavy-duty
diesel engine maintenance specify a minimum interval for DPF ash
cleanout from 100,000 to 150,000 mi. Many manufacturers design DPF
systems with longer maintenance intervals.
    \12\ See http://www.arb.ca.gov/diesel/tru/documents/ashguide.pdf.
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    Regeneration, however, is a type of routine DPF cleaning that must
occur regularly, and for which EPA does not specify a minimum interval
in its regulations, in contrast to the ash cleaning process. At its
very essence, regeneration involves burning off the accumulated soot.
Since this burning can involve extra heat and/or oxygen or oxygen-
containing compounds, this must be done carefully and safely to avoid
uncontrolled burns. The discussion below in Section III.B.(1)(b)
describes the three types of routine DPF regeneration: Passive
regeneration, automatic active regeneration, and manual (parked) active
regeneration. Additional discussion is provided in the accompanying
Notice of Proposed Rulemaking published elsewhere in today's Federal
Register and in a memorandum to the docket.\13\ Below, we discuss the
reason why regeneration is needed at all.
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    \13\ See memo dated May 4, 2012, ``Diesel Particulate Filter
Regeneration,'' Docket ID EPA-HQ-OAR-2011-1032.
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(a) Failure of a DPF
    When the style of filter installed on a diesel vehicle is the wall-
flow type that is predominant in the market today, it physically traps
so much of the PM that the particles accumulate on the inside of the
filter and if not burned off, this PM can over time block the passages
through the filtering media, making it more restrictive to exhaust
flow. This is commonly referred to as ``trap plugging.'' Some other
styles of filter, such as flow-through DPF's, are less prone to
plugging, but do not generally reduce the PM emission rate sufficiently
to meet today's stringent PM standard. Any time something gets in the
way of free flowing air through an engine, it creates what we call
``exhaust backpressure.'' Even a clean, new DPF generates a small
amount of exhaust backpressure due to the porous walls through which
all of the exhaust flows.
    Engines can tolerate a certain range of exhaust backpressure. When
an increase in this backpressure, or resistance, is detected, engines
can compensate to a point. An increase in exhaust backpressure from a
DPF trapping more and more PM represents increased work demanded from
the engine to force the exhaust gas through the increasingly

restrictive DPF. However, unless the DPF is frequently cleansed of the
trapped PM, this increased work demand can lead to reductions in engine
performance and increases in fuel consumption. This loss in performance
may be noticed by the vehicle operator in terms of poor acceleration
and generally poor drivability of the vehicle.
    If a DPF is not regenerated and it becomes plugged, there is a risk
of two types of failure. The degree of this risk and which consequence
may be experienced will depend on the engine and emission control
system design. One consequence is that the lack of air flowing through
an engine will cause an engine to shut down because it can no longer
compensate for the extra work being demanded of it. The other is a risk
of catastrophic DPF failure when excessive amounts of trapped PM begin
to oxidize at high temperatures (i.e., DPF regeneration temperatures
above 1,000 [deg]C) leading to a ``runaway'' combustion of the PM
within the DPF. This can cause temperatures in the filter media to
increase beyond its physical tolerance, possibly creating high thermal
stresses where the DPF materials could crack or melt. This is an unsafe
condition, presenting physical danger to occupants as well as to
objects and persons near the vehicle. Further, catastrophic failure can
allow significant amounts of the diesel PM to pass through the DPF
without being captured. That is, the DPF is destroyed and PM emission
control is lost. For all these reasons, most manufacturers generally
design their emission control systems to prevent uncontrolled shutdown
or runaway DPF regeneration by programming the engine's electronic
control module (ECM) to limit maximum engine speed, torque and/or power
when excessive backpressures are detected. This mode of engine
operation at reduced performance may allow a vehicle to ``limp home''
to receive service. In extreme cases the ECM may command the engine to
shut down to prevent a catastrophic failure.
(b) Types of Regeneration
    There are three types of routine DPF regeneration. Passive
regeneration refers to methods that rely strictly on the temperatures
and constituents normally available in the vehicle's exhaust to oxidize
PM from a DPF in a given vehicle application. Passive regeneration is
an automatic process that occurs without the intervention of an
engine's on-board diagnostic and control systems, and often without any
operator notice or knowledge. Passive regeneration is often a
continuous process, because of which, it is sometimes referred to as
continuous regeneration. In a vehicle whose normal operation does not
generate temperatures needed for passive DPF regeneration, the system
needs a little help to clean itself. This process is called active
regeneration, and supplemental heat inputs to the exhaust are provided
to initiate soot oxidation. There are two types of active regeneration:
Those that may occur automatically either while the vehicle is in
motion, while idling, or while powering an auxiliary device such as a
pump or ladder (power take-off (PTO) mode)), and those that must be
driver-initiated and occur only while the vehicle is stationary and
out-of-service.
    Vehicles with automatic active regeneration systems require
operators to be alert to dashboard lamps and indicators. Written
instructions are provided to operators to explain what each lamp means
(such as high temperatures or need for regeneration) and what action is
called for (such as driving at highway speeds or initiating a manual
active regeneration). Because EPA emissions standards are performance
based; and therefore, do not dictate any required emission control
system technologies or configurations, each manufacturer has the
discretion to program the timing and sequence of lamps as needed to
inform drivers of the condition of the emission control system. As
noted above, it is not uncommon in today's heavy-duty fleet for an
engine's ECM to limit its maximum speed, torque or power when a
plugging DPF is detected. These engine and emission control system
protection measures can alert drivers to the need to change driving
conditions to facilitate automatic active regeneration or to make plans
to allow for a manual active regeneration.
    A manual active regeneration allows the engine's ECM to increase
engine speed and exhaust temperature to a greater extent than what is
typically allowed during an automatic active regeneration. Because the
ECM takes full control of an engine during a manual active
regeneration, the vehicle must remain parked and not used for other
purposes, such as pumping water in PTO mode. Some manual active
regenerations may require towing the vehicle to a special service
center, and may occur while the DPF is on the vehicle, or offline with
the DPF removed from the vehicle. In such cases, if a spare DPF is not
available, the vehicle could be out of service overnight. If a driver
disregards such warnings, the risk of uncontrolled engine shutdown or a
catastrophic DPF failure may increase. EPA encourages the design of
robust systems calling for minimal driver interventions, while
providing drivers with clear and early indicators before any
interventions are needed. EPA also encourages accurate and thorough
operator training to ensure that the correct remedial action is taken
at the earliest available time.
    Actively regenerating DPF systems typically require sufficient air
flow, temperature and soot accumulation before an automatic active
regeneration will be requested by the engine's ECM. As mentioned above,
this may occur either while the vehicle is in motion or parked, if pre-
set engine operating conditions are met (such as speed and
temperature). When the engine's ECM signals the initiation of an
automatic active regeneration and the extra heat is generated, an ideal
DPF system accomplishes this as a transparent process, with no effects
perceivable by the driver.
    A variety of manufacturer approaches can be taken to produce the
supplemental heat needed for active regeneration. Diesel engines of MY
2007 or newer often incorporate one or more of the following
approaches:
     On-board electrical heaters upstream of the filter.
     Air-intake throttling in one or more of the engine
cylinders. When necessary, this device would limit the amount of air
entering the engine, raising the exhaust temperature and facilitating
regeneration.
     Exhaust brake activation. When necessary, this device
would limit the amount of exhaust exiting the engine, raising the
exhaust temperature and facilitating regeneration.
     Engine speed increases. This approach is sometimes used in
combination with the other approaches to deliver more heat to the
filter to facilitate regeneration.
     Post top-dead-center (TDC) fuel injection. Injecting small
amounts of fuel in the cylinders of a diesel engine after pistons have
reached TDC introduces a small amount of unburned fuel in the engine's
exhaust gases. This unburned fuel can then be oxidized over an
oxidation catalyst upstream of the filter or oxidized over a catalyzed
particulate filter to combust accumulated particulate matter.
     Post injection of diesel fuel in the exhaust upstream of
an oxidation catalyst and/or catalyzed particulate filter. This method
serves to generate heat used to combust accumulated particulates by
oxidizing fuel across a catalyst present on the filter or on an
oxidation catalyst upstream of the filter.

     On-board fuel burners upstream of the filter.\14\
---------------------------------------------------------------------------

    \14\ MECA Diesel Particulate Filter Maintenance: Current
Practices and Experience (June 2005) http://www.meca.org/galleries/default-file/Filter_Maintenance_White_Paper_605_final.pdf.
---------------------------------------------------------------------------

    These are presented here merely as examples, and are by no means a
complete list of the strategies available to manufacturers when
designing engines that use automatic active DPF regeneration, though
not all may be applicable to all engines. A common approach that gets a
lot of consumer attention is the use of fuel burners or fuel injection
strategies. This approach is often called ``dosing.'' Vehicle owners
may notice an increase in fuel consumption when driving a vehicle that
relies heavily on fuel dosing for its automatic active regenerations.
In this case, when an engine's ECM gives the signal, the doser injects
a metered amount of diesel fuel into the exhaust flow (or cylinders),
which reacts with the DPF catalyst to raise the temperature to a point
that enables regeneration. EPA does not have information about which
manufacturers employ this technique or the number or types of vehicles
with engines that use fuel dosing as part of the active regeneration
strategy. Estimates of the additional fuel use by a vehicle whose DPF
regeneration system employs fuel dosing are described in the Notice of
Proposed Rulemaking published elsewhere in today's Federal Register.
This is also mentioned here because one of the possible outcomes of
this EPA action is that some manufacturers may alter their strategies
for automatic active regenerations on emergency vehicles, which may
have a modest effect on supplemental fuel use due to dosing.
(2) Why are emergency vehicles having problems with DPF regeneration?
    At the time of promulgation of the heavy-duty highway rule, EPA and
the engine manufacturers expected the 2007-compliant engine emission
control systems would be integrated with advanced engine controls to
ensure DPF regeneration under all vehicle operating conditions and
environments. While this is widely true today, the experience of the
rule implementation thus far indicates there are still some exceptions.
    Although EPA is aware of a relatively small number of emergency
vehicles that are experiencing problems with DPF regeneration, of those
that are having problems, most of the problems can be related to the
vehicle's duty cycle, the ambient conditions, and/or the engine's
combustion characteristics. A vehicle's duty cycle means how it is
driven, including its speeds, loads, and distances, as well as time out
of service and time spent idling. A vehicle's duty cycle can vary by
the demographic of the service area, including whether the vehicle
responds to emergencies in a rural or urban community, and whether it
drives over flat or hilly terrain. Because DPF regeneration requires
heat and oxygen (basic ingredients for combustion), the success of DPF
regeneration strategies can also be influenced by ambient conditions
such as extreme cold winter temperatures and whether the vehicle
operates near sea level or at a high elevation. The engine combustion
and exhaust characteristics can influence the success of a DPF
regeneration strategy since parameters such as engine-out
NOX and PM emission levels can influence how easily the soot
can be oxidized, and how much soot needs to be oxidized and how often.
    Both the engine's duty cycle and the overall control strategy of
the engine's emission control system play a large role in the success
of integrating a DPF with an engine to control PM emissions. In this
section we provide additional discussion of how engine combustion
characteristics and vehicle duty cycle can lead to DPF regeneration
problems on emergency vehicles. In Section III.D, below, we discuss our
regulatory action to address these issues. While our approach
specifically targets engine combustion characteristics and emission
control system design, we encourage emergency vehicle owners to inquire
with their dealers and manufacturers regarding suitable vehicle and
engine options that are appropriate for their duty cycle as well as
their demographic and geographic location.
(a) Engine Combustion Characteristics
    Engine combustion characteristics can be designed to enable
continuous passive regeneration or to rely heavily on automatic active
regeneration. As mentioned above, regeneration is a combustion process,
burning off the accumulated PM or soot. The PM is created because the
initial combustion process in the engine was imperfect. To completely
convert all fuel to CO2 and water, the combustion process
needs more heat and oxygen. Both of these things create NOX
because nitrogen (N2) is naturally present in the air and
readily oxidizes at high temperatures. Thus there is a NOX-
PM trade-off of most diesel combustion processes (homogeneous charge
compression ignition being an exception) where lower combustion
temperatures help control NOX but create more PM, and higher
temperatures that destroy PM (or prevent it from being created) can
generate more NOX.
    In an engine with a DPF system, combustion settings, or
calibrations that enable continuous passive regeneration, tend to be
those with higher engine-out NOX and lower engine-out PM,
partly because of the higher temperatures that create the
NOX, partly because of the NOX itself that can
act as an oxidizer (to burn off soot), and partly because of the
lighter soot loading rate. In contrast, engine calibrations that may
lead to a heavy reliance on automatic active regeneration tend to be
those with lower engine-out NOX and higher engine-out PM,
partly because of the lower temperatures, partly because of a lack of
helpful NOX, and partly because of a heavier soot loading
rate. Note that ``engine-out'' means emissions upstream of any after-
treatment cleaning devices such as DPF or SCR. An example of a DPF
system that may rely almost exclusively on active regeneration to
maintain a clean PM filter, from an engine calibration perspective,
would be an engine using advanced exhaust gas recirculation, because it
would have very low engine-out NOX and relatively high
engine-out PM. An example of a DPF system that may rarely experience
automatic active regeneration (and frequently passively regenerate),
from an engine calibration perspective, would be an engine using SCR to
control NOX, because it could have comparatively high
engine-out NOX and relatively low engine-out PM. The SCR
after-treatment would then reduce the high engine-out NOX to
provide very low tailpipe NOX.
    Thus it is important to note that this NOX-PM trade-off
is a critical design parameter when developing an engine that will be
successfully integrated with a DPF-equipped emission control system. To
date, all of the concerns expressed to EPA regarding emergency vehicles
with DPF regeneration issues have been for vehicles that do not employ
SCR technology, and thus may have higher engine-out PM. The differences
in engine combustion characteristics of the MY 2007 vehicles compared
to those of the majority of MY 2010+ vehicles support the concept that
the emergency vehicle fleet may experience fewer DPF regeneration
troubles as it migrates to engines that use after-treatment to meet
EPA's 2010 NOX standards. Such a trend may indicate that
some engine manufacturers may see a greater need to address in-use
emergency vehicles than new vehicles.
(b) Duty Cycles
    As noted above, the duty cycle of a vehicle is one of the factors
that

influences how often the DPF regenerates passively or actively. It is
important to note that all DPF systems with active regeneration
components also have the capability to passively oxidize soot
accumulated on the filter, though some of the above-described factors
may inhibit successful passive regeneration. Operation at highway
speeds and high engine loads (high load means demanding more work from
the engine, such as accelerating, driving uphill or carrying heavy
cargo) typically leads to successful passive regeneration of a DPF. An
example from a duty-cycle perspective of a vehicle that frequently
experiences automatic passive regeneration would be a long-haul
tractor-trailer. There is also often a threshold of speed or load that
is required for automatic active regeneration strategies as well,
though not as great as for passive regeneration--often at least 5
miles/hour or parked with a PTO engaged. In some vehicles, passive
regeneration occurs so rarely that a DPF system relies almost
exclusively on active regenerations to maintain a clean PM filter. An
example of this from a duty-cycle perspective would be a vehicle that
operates at idle, low speed and low load over most of its duty cycle.
Many emergency vehicles fall into this category.
    A detailed discussion of the duty cycles of emergency vehicles is
provided in the Notice of Proposed Rulemaking published elsewhere in
Today's Federal Register. The data provided in that discussion indicate
that engines on emergency vehicles across the country are commonly
operated over duty cycles that offer very limited opportunities to
regenerate DPF's. It is also important to note that emergency vehicles
do not typically get deployed on planned duty schedules with
predictable blocks of garage time for servicing or maintenance. While
some other types of vocational vehicles may have duty cycles with many
characteristics similar to those shown above, emergency vehicles are
unique in their need to be ready to deploy at any moment for the
purpose of protecting public safety and welfare by saving human lives
that may be in immediate danger.
    When trucks with an engine-driven PTO are working in a stationary
PTO mode, some engines achieve the conditions to enable an automatic
active regeneration during this time. While this is normally designed
to be a transparent process, in practice some effects of this type of
regeneration have been noticed by operators. EPA has received
information from fire chiefs indicating that there have been instances
where engine ECM's took control from the operator during water pumping
operations. When an automatic active regeneration is initiated during a
water pumping operation, for example, an ECM may be programmed to alter
throttle position or engine speed to achieve the conditions needed to
complete an automatic active regeneration. Depending on the design of
the water pumping system's pressure regulation, this may in turn affect
the water pressure in the fire hoses. EPA has not heard of this
occurring on a widespread basis, and has reason to believe that
affected engine and truck manufacturers have identified and corrected
this issue on some vehicles. EPA's current regulations already allow
manufacturers to develop and request EPA approval for certification of
engines with emission control strategies where the process of
undergoing automatic active regeneration would not interfere with
safely pumping fire suppressant.
    While not addressed directly in this action, there are technologies
that could be implemented to decrease the amount of time emergency
vehicles spend with their main engines operating at light loads and at
idle. These technologies include electronically programmed automatic
engine start/stop systems and hybrids. Automatic start/stop systems
automatically stop and start an engine depending upon whether or not it
is needed to supply power to the vehicle. This technology is already
being implemented on other heavy-duty vehicles to decrease unnecessary
engine idling. Hybrid drivetrains also decrease engine idling with an
integrated alternate power source such as a battery. We are currently
seeing an increase in the use of hybrid technologies in heavy-duty
diesel vocational vehicles. Garbage trucks, utility company trucks, and
other work trucks are using hybrid technology to power on-board
hydraulic systems and cab heating and cooling systems. In conventional
vehicles these systems are powered by a main engine typically operating
at light load or at idle. Because automatic start/stop and hybrid
technologies improve fuel economy and decrease greenhouse gas
emissions, we believe that they will be used in more and more vehicles
in the future. We believe there is potential for these technologies to
be integrated into future designs of emergency vehicles to decrease
their operation at light loads and at idle. Such technologies would not
only improve fuel economy and decrease greenhouse gas emissions from
emergency vehicles, they would also help to prevent their diesel
particulate filters from becoming plugged due to excessive operation at
light loads and at idle. While we are not taking any specific action at
this time related to decreasing the amount of time emergency vehicles
operate at light load or at idle, in the accompanying NPRM, we request
comment on the potential for application of alternate power sources and
idle reduction technologies on emergency vehicles.
(3) What are the concerns for emergency vehicles using SCR?
    Selective Catalytic Reduction (SCR) is an exhaust after-treatment
system used to control NOX emissions from heavy-duty engines
by converting NOX into nitrogen (N2) and water
(H2O). The technology depends on the use of a catalytic
converter and a chemical reducing agent, which generally is in an
aqueous urea solution, and is often referred to as diesel exhaust fluid
(DEF). Some trade names for this chemical reductant include AdBlue,
BlueDef, NOXBlue, and TerraCair.
    Most engine manufacturers chose to comply with the 2010
NOX emission standard by adding SCR to their engine models.
In general, the approach with an SCR system has been a sound and cost
effective pathway to comply with EPA's 2010 emissions standards, and it
is the primary path being used today.
    DEF is injected into the exhaust upstream of the SCR catalyst where
it forms ammonia and carbon dioxide. The ammonia then reacts with NO
and NO2, so that one molecule of urea can reduce two
molecules of NO or one molecule of NO2. A robust SCR system
can achieve about 90 percent reduction in cycle-weighted NOX
emissions. Improvements have been made over the last several years to
improve the NOX conversion rate and reduce the impact of
lower exhaust temperatures on the conversion efficiency.
    Because an SCR system is only effective when DEF is injected into
the exhaust, we consider refilling a vehicle's DEF tank to be a
critical emission-related engine maintenance requirement. We are
proposing to take action to establish this in our regulations, as
described in Section V of the Notice of Proposed Rulemaking published
elsewhere in today's Federal Register. Therefore, manufacturers have
implemented a number of strategies to induce a vehicle operator to
refill a vehicle's DEF tank when needed. These operator inducements
generally include first illuminating one or more dashboard lights to
warn the operator that the DEF tank needs to be refilled soon. However,
if such initial inducements are persistently ignored by the vehicle
operator, eventually additional

inducements are typically activated that decrease the maximum speed or
power of the vehicle. These additional inducements are intended to
create conditions making operational conditions of the vehicle
increasingly unacceptable if the initial dashboard lamp illumination
inducements are persistently ignored. Similar inducements may occur in
cases where DEF quality does not meet system specifications, or if the
SCR system is not functioning correctly for another reason.
    While decreasing vehicle performance can be an effective inducement
strategy, we believe it may not be appropriate in all situations for
emergency vehicles because of their special need to be ready at any
moment for the purpose of protecting public safety and welfare by
saving human lives that may be in immediate danger. We recognized this
during the initial implementation of our 2010 NOX standards,
and we worked with the Fire Apparatus Manufacturers' Association
(FAMA), the Ambulance Manufacturers Division of the National Truck
Equipment Manufacturers Association, and the International Association
of Fire Chiefs to support the publication of a May 18, 2010 memo that
instructed emergency vehicle manufacturers and engine manufacturers to
implement less severe inducement strategies for emergency vehicles.\15\
In this rule we are taking additional steps so that emergency vehicle
manufacturers and engine manufacturers have the option to further
reduce the severity or eliminate altogether any performance related
inducements that are or could be implemented on emergency vehicles and
their engines during emergency situations. We believe that this
additional flexibility will help to prevent any abnormal condition of a
vehicle's emission control system from adversely affecting the speed,
torque, or power of an emergency vehicle during emergency situations.
---------------------------------------------------------------------------

    \15\ FAMA 2010, Emergency Vehicle SCR and DEF Inducement
Guidelines; 2010 Engine Emissions Control Requirements.
---------------------------------------------------------------------------

C. What would occur if EPA took no action?

(1) The Industry Would Continue To Get Smarter
    Improving the components of diesel particulate filters is the
current subject of research and development activities within the
automotive and air pollution control industries. Aspects that are being
improved include filter ash storage capacity, filter pressure drop,
substrate durability, catalyst activity, as well as other physical and
chemical properties that can optimize the device for heavy-duty vehicle
applications.
    Engine manufacturers have taken a systems approach, optimizing the
engine with its after-treatment system to realize the best overall
performance possible. Manufacturers can manage the functioning of the
emission control system by adjusting parameters such as the thermal
profile of the after-treatment system, the exhaust gas chemical
composition, the rate of consumption of DEF, the rate of particle
deposition, and the conditions under which DPF regenerations (soot
cleaning) may occur.
    In a broad and general sense, the trend is that DPF's are slowly
becoming even more robust without EPA intervention. Future DPF's will
need fewer total regenerations during the useful life of the engine and
control system, more passive and fewer active regenerations will occur,
and manual regenerations will become rarer.
    In addition, vehicle operators and fleet managers will continue to
become more experienced with this new generation of sophisticated
electronically-controlled vehicles. Manufacturers across the country
are providing training on actions fleet managers can take to decrease
problems with DPF regenerations. These actions include:
 Use low-ash engine oils.
 Avoid extended idling.
 Maintain insulation on the exhaust pipe.
 Maintain the crankcase filter.
 Periodically operate a vehicle at higher speeds and loads.
    The Technology & Maintenance Council (TMC) of the American Trucking
Associations conducted a survey in late 2011 to compare user
experiences between EPA 2010, EPA 2007, and EPA 2004 vintage
trucks.\16\ According to TMC, 72 percent of the survey respondents
indicated that driver understanding of the 2007-vintage after-treatment
system was worse than driver understanding of the 2004-vintage after-
treatment system, and 33 percent of respondents indicated that driver
understanding of the 2010-vintage after-treatment system was worse than
driver understanding of the 2007-vintage after-treatment system. The
responses regarding driver understanding of fault codes and dash lamps
indicated that drivers have 69 percent poorer understanding of 2007 vs.
2004 fault codes and dash lamps, and 50 percent poorer understanding of
2010 vs. 2007 fault codes and dash lamps. We expect that this education
component will gradually improve over time without EPA intervention.
---------------------------------------------------------------------------

    \16\ American Trucking Associations, Technology & Maintenance
Council, S3 Engine Study Group. Survey conducted Fall 2011, public
slides dated February 2012 available at http://www.truckline.com/Federation/Councils/TMC/Documents/2012%20Annual%20Meeting%20and%20Exhibition%20Documents/TMC12A_TECH2.pdf.
---------------------------------------------------------------------------

(2) The Fleet Would Continue to Migrate to the 2010 Standards
    Vehicles with 2010-compliant heavy-duty diesel engines tend to
place different demands on their DPF systems than pre-2010 vehicles.
With the addition of NOX after-treatment such as SCR,
engines may be tuned to emit lower engine-out PM (recall the
NOX-PM trade-off described above). When an SCR system is
integrated, it provides the opportunity to run an engine at lower soot
levels and elevated levels of NO2, which is a chemical
species that efficiently oxidizes the soot in the absence of elevated
temperatures. It is EPA's expectation that vehicles of MY 2010 and
beyond, particularly those using SCR, will generally experience fewer
troubles with DPF's than the earlier model year vehicles, due to the
nature of the on-board technology as well as the many years of
experience gained by manufacturers since 2007. The 2011 TMC survey
included an assessment of relative satisfaction levels between EPA
2010, EPA 2007, and EPA 2004 vintage trucks. The survey results
indicate that after-treatment durability is better with EPA 2010 trucks
compared to EPA 2007 trucks, with less time out of service.\17\ As an
illustration, according to a Volvo product brochure, the company's EPA
2010-compliant trucks eliminate the need for active DPF regeneration,
reducing driver involvement with the emission control system, using a
design that allows for the DPF system to reliably oxidize accumulated
soot using continuous passive regeneration.\18\
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    \17\ See ATA/TMC, Note 16.
    \18\ See Volvo 2010 product brochure, ``Volvo's SCR No Regen
Engine,'' available at http://www.volvotrucks.com/SiteCollectionDocuments/VTNA_Tree/ILF/Products/2010/09-VTM075_NoRegen_SS_041609.pdf.
---------------------------------------------------------------------------

(3) Some Trucks Would Continue to Experience Problems
    Even though such trends would indicate that instances of emergency
vehicles experiencing difficulty managing regeneration of DPF's would
decrease, in the absence of this EPA action, some vehicles would be
likely to continue to experience some problems.
    EPA has learned that some engine manufacturers have disabled these
engine protection measures on some emergency vehicles. In these cases
the

manufacturer has reasoned that an operator should be allowed to remain
in control of an emergency vehicle even facing risk of catastrophic
failure, with the consequences of that failure being less severe than
the consequences of the vehicle prematurely losing power, torque and/or
speed while performing emergency services.
    Without a clear action from EPA to provide the regulatory
flexibility needed for swift deployment of robust remedies throughout
the emergency vehicle fleet, implementation of best practices could be
inconsistent, insufficient, or even impossible due to regulatory
constraints. Some vehicles would continue to experience frequent
plugging of DPF's, frequent forced filter regenerations, and reduced
engine power, speed or torque that diminish the ability of first
responders to save lives and property. There would also remain a
heightened risk that an emergency vehicle could be taken out of service
when it is most needed.

D. Regulatory Action

    As described above in Section III.C, many DPF-equipped vehicles
include engine controls and driver alerts that lead to decreases in
maximum speed, torque, or power when DPF backpressure exceeds normal
levels, as protective measures for either the engine or the DPF, or as
inducements for the operator to immediately conduct DPF regeneration.
Similarly, vehicles equipped with selective catalytic reduction (SCR)
systems for NOX reduction currently have engine controls and
driver alerts that lead to eventual loss of speed, torque, or power
when the SCR controls detect abnormal conditions (such as a
malfunction, low DEF levels, etc.), as inducements to take immediate
corrective action to allow the SCR to function normally. In most
vehicles, these alerts and inducements may be easily avoided with
normal driving and routine maintenance, and if activated, these
inducements would not have any significant effect on public safety and
welfare. In emergency vehicles, however, should any of these limits on
maximum speed, torque, or power occur while a vehicle is responding to
an emergency, it could be a matter of life or death. To address these
issues that could otherwise limit the maximum speed, torque or power of
an emergency vehicle's engine when it is needed most, EPA is proposing
to amend 40 CFR part 86 to revise the definition of defeat device; add
new definitions of emergency vehicle, ambulance and fire truck; and add
new labeling requirements for new on-highway engines with approved
Auxiliary Emission Control Devices for emergency vehicles. EPA is also
amending its regulations at 40 CFR part 1039 to revise the definition
of defeat device, add a new definition of emergency equipment, and add
a new labeling requirement for nonroad engines with approved Auxiliary
Emission Control Devices for emergency equipment.
    In our current regulations, engine manufacturers may request as
part of an application for new engine or vehicle certification, and EPA
may approve, Auxiliary Emission Control Devices, if they are not
determined to be ``defeat devices.'' Auxiliary Emission Control
Devices, or AECD's, are any design element of an engine's emission
control system that senses temperature, vehicle speed, engine RPM,
transmission gear, manifold vacuum, or any other parameter for the
purpose of activating, modulating, delaying, or deactivating the
operation of any part of the emission control system.\19\ Some AECD's
can temporarily decrease the effectiveness of an emission control
system. This type of AECD is only permitted in very limited situations,
for example, when such excursions are deemed to be necessary in order
to protect the vehicle, engine, and or emission control system during
limited modes of operation.
---------------------------------------------------------------------------

    \19\ See 40 CFR 86.082-2 .
---------------------------------------------------------------------------

    A defeat device is a type of AECD that reduces the effectiveness of
vehicle emission controls in situations when such reduction in
effectiveness is not approved or permitted by EPA. Defeat devices are
not permitted by the Clean Air Act or EPA.
    Approvals of AECD's are made by EPA on a case-by-case basis. In
applications for engine certification, manufacturers must include a
detailed description of each AECD to be installed in or on any vehicle
(or engine) covered by the application, as well as a detailed
justification of each AECD that results in a reduction in effectiveness
of the emission control system. According to 40 CFR 86.094-
21(b)(1)(i)(B), EPA may disapprove a request for an AECD based on
consideration of currently available technology. Use of an unauthorized
or disapproved AECD can be considered a violation of section 203 of the
Act.\20\
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    \20\ See 40 CFR 86.094-21 and 094-22.
---------------------------------------------------------------------------

    In this action, EPA is proposing to revise the definition of defeat
device at 40 CFR 86.004-2, 86.1803-01, and 40 CFR 1039.115 to exclude
AECD's that apply only for engines on emergency vehicles, where the
need for an AECD is justified in terms of preventing the vehicle or
equipment from losing speed, torque, or power due to abnormal
conditions of the emission control system, or in terms of preventing
such abnormal conditions from occurring during operation related to
emergency response.
    In this action, EPA is proposing to define an emergency vehicle as
a vehicle that is an ambulance or a fire truck. EPA is proposing to
adopt a definition of ambulance consistent with the current U.S.
General Services Administration Star of Life specification.\21\ EPA is
proposing to define fire truck as a vehicle designed to be used under
emergency conditions to transport personnel and equipment and to
support the suppression of fires and mitigation of other hazardous
situations, consistent with the scope of standards for automotive fire
apparatus issued by the National Fire Protection Association.\22\ We
are defining emergency equipment as specialized vehicles to perform
aircraft rescue and firefighting functions at airports, or wildland
fire apparatus. With these definitions, it is EPA's intent to include
vehicles that are purpose-built and exclusively dedicated to
firefighting, emergency/rescue medical transport, and/or performing
other rescue or emergency personnel or equipment transport functions
related to saving lives and reducing injuries coincident with fires and
other hazardous situations. EPA requests comment on whether we should
refine or expand our definition of emergency vehicle within the scope
of this action to include those equipped with heavy-duty diesel engines
that serve other civilian rescue, law enforcement or emergency response
functions. We are especially interested in information regarding
instances of such vehicles experiencing or risking loss of power, speed
or torque due to abnormal conditions of the emission control system,
and how that may inhibit mission-critical life- and property-saving
work.
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    \21\ U.S. General Services Administration, Federal Specification
for the Star-of-Life Ambulance, August 1, 2007, http://www.deltaveh.com/f.pdf.
    \22\ See National Fire Protection Association Web page. Accessed
April 2012 at http://www.nfpa.org/catalog/product.asp?title=Code-1901-2009-Automotive-Fire-Apparatus&category%5Fname=&pid=190109⌖%5Fpid=190109&src%5Fpid=&link%5Ftype=search&icid=.
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    EPA is also adopting an associated engine labeling requirement so
that engines with approved emergency vehicle AECD's will be clearly
identified and distinguished from other similar engines.
    As mentioned above in Section III.B, some engine manufacturers
currently specify that when an engine is sold for installation in an
emergency vehicle,

some of the default power, torque or speed inducements be de-activated
or set to alternate, less severe settings. In such applications, when
the DPF system requests regeneration, the warning lights remain
illuminated while the vehicle remains in complete control of the
driver. In these cases the manufacturer has likely reasoned that the
consequences of catastrophic failure would be less severe than the
consequences of the vehicle prematurely losing power, torque and/or
speed while performing emergency services. EPA has granted related
AECD's in the past.
    However, without the optional flexibilities provided by EPA in this
action, manufacturers could be prevented from implementing truly
failsafe solutions for all affected vehicles. For example, while
current custom solutions may allow an emergency vehicle to continue
pumping water or transporting a person to safety, its DPF would
continue to accumulate particles and the risk of catastrophic failure
would increase.
    In this action, EPA is adopting amendments so that manufacturers
can apply for (and EPA can approve) AECD's that may be justified in
terms of preventing the occurrence of abnormal conditions of the
emission control systems for emergency vehicles or in terms of
preventing the engines from losing speed, torque, or power due to such
abnormal conditions. In this context, EPA would consider abnormal
conditions to be parameters outside normal ranges for proper operation,
such as excessive exhaust backpressure from high soot loading on a DPF
or insufficient DEF for use with an SCR system.
    EPA is encouraging manufacturers to apply for AECD's that are
tailored for engines on emergency vehicles, considering the duty cycle
information presented in the accompanying NPRM, along with any other
information needed to design failsafe emission control systems for new
emergency vehicles. EPA is also encouraging manufacturers to design
field modifications to address these issues on in-use emergency
vehicles, including those whose engines are no longer in production.
Further discussion of field modifications is provided below in Section
III.E(2).
    To achieve these goals, EPA understands that increased flexibility
will be needed because EPA's strict NOX and PM standards
present many design constraints. Below we describe some solutions that
EPA believes it could approve as part of an emergency vehicle AECD or
field modification, as adopted. EPA is encouraging engine manufacturers
to apply for emergency vehicle AECD's and/or field modifications for
in-use emergency vehicles for which service disruptions related to
abnormal conditions of emission control systems may occur or have
occurred. EPA suggests that such AECD's or field modifications could
include, but are not limited to, one or more of the following
strategies:
(1) Liberalized Regeneration Requests
    It is current practice that most modern diesel engine ECM's are set
to initiate an automatic active regeneration only above a designated
DPF soot load, and those vehicles equipped with manual regeneration
switches are set to not allow the option of initiating manual active
regeneration until an even greater soot load is detected. The reason
why manufacturers do this is related to certification of engine
families and vehicle test groups. If manufacturers can limit the
frequency of regenerations by design, then they can be assured that
average emissions will remain below the certified average emission
level. Excess regenerations could lead to higher average emissions,
since some exhaust emissions increase during regeneration. Particularly
for engines not equipped with SCR systems, NOX emissions can
increase by an order of magnitude during regeneration, and these
temporary increases in emission are accounted for in EPA's
certification process. See the accompanying NPRM for more information
about the emissions impacts of DPF regenerations. In addition, excess
regenerations could shorten the useful life of the DPF system since
high temperatures place stress on filter substrates.
    EPA believes that emergency vehicle AECD's that enable more
frequent automatic active and manual active DPF regenerations,
associated with a wider range of soot loads could improve the
reliability of DPF systems without significantly compromising emissions
reductions or durability. As explained below Section III.E(4), EPA does
not expect this provision to affect other aspects of certification. For
emergency vehicles with approved AECD's that involve changes in the
frequency of regeneration, the resulting increase in NOX
emissions will not be counted against certification levels for
applicable engine families or vehicle test groups. Furthermore,
emissions certification testing may be conducted with any approved
AECD's for emergency vehicle or equipment deactivated. According to
EPA's current engine certification data, engines from MYs 2008 and 2011
have an average maximum automatic active regeneration frequency near 20
percent, with the typical frequency between three and seven percent.
Those with frequencies near zero rely almost exclusively on passive
regeneration.\23\
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    \23\ Frequency in percent refers to the fraction of engine test
cycles during which an automatic active regeneration occurs.
---------------------------------------------------------------------------

(2) Engine Recalibration
    As mentioned above, in-cylinder combustion chemistry dictates a
NOX-PM trade-off where engines calibrated to reduce in-
cylinder NOX tend to have higher PM levels. These factors
lead to higher rates of particle accumulation and lower rates of
particle oxidation on filters. EPA believes that AECD's that
incorporate engine calibration modifications could enable operation in
a ``low soot mode'' with a reduced rate of particle deposition that
would lead to more frequent and effective passive regenerations. Such
calibration modifications could also extend the operating time between
all types of regenerations, improve active regeneration effectiveness,
and boost reliability of the DPF systems. On engines with downstream
(i.e., SCR) NOX controls, SCR control could be modulated
such that engine recalibration would not significantly affect
NOX emissions. On engines without downstream NOX
controls, EPA believes that some degree of increased NOX
emissions during the conditions justified by the AECD would be
approvable for emergency vehicles. As explained below in Section
III.E(4), EPA does not expect this provision to affect other aspects of
certification. When manufacturers calculate the average NOX
emissions during a test cycle, they incorporate data regarding both the
frequency of regeneration and the increase in NOX emissions
during regeneration. For emergency vehicles with approved AECD's that
involve recalibration to alter regeneration frequency or average
NOX emissions, the resulting increase in NOX
emissions will not be counted against certification levels for
applicable engine families or vehicle test groups. Furthermore,
emissions certification testing may be conducted with any approved
AECD's for emergency vehicle or equipment deactivated. A discussion of
the estimated emissions impacts of recalibration is provided in the
Notice of Proposed Rulemaking published elsewhere in today's Federal
Register.
(3) Backpressure Relief
    It is EPA's objective that all of our clean diesel emissions
standards be implemented with reliable technologies

that require a minimum amount of driver intervention and do not
compromise the utility of vehicles. EPA understands that manufacturers
are motivated to seek design solutions that are cost effective and
easily deployable. However, by focusing solely on preventive measures
such as those described above, manufacturers may not achieve a
completely failsafe DPF strategy on all emergency vehicles. EPA
anticipates that some vehicles may benefit from an additional failsafe
measure that relieves engine exhaust backpressure as a last resort to
prevent loss of engine speed, torque or power. There are products on
the market today that could be configured to temporarily relieve
excessive engine exhaust backpressure when detected, then return the
system to normal at the instant that backpressure returns to a safe
level. Such a device may be justified as a failsafe measure, and may be
included as part of an overall strategy that also includes preventive
measures, if justified and properly limited, where excess PM emissions
would be expected to be emitted only during a small fraction of vehicle
operation. That is, the vast majority of DPF operating cycles would be
expected to have continuous PM emission control, while any temporary
backpressure relief that reduced PM control or allowed bypass of
controls would be expected relatively infrequently.

E. What engines and vehicles are affected?

    Today's action applies to new and in-use fire trucks and
ambulances, new and in-use airport fire apparatus and wildland fire
apparatus, and heavy-duty diesel engines on these emergency vehicles
and equipment.
(1) Newly Certified Engines
    Of those new diesel engines covered by EPA's current heavy-duty
diesel standards, only those installed in vehicles or equipment meeting
the definition of emergency vehicle or emergency equipment will be
eligible to obtain an approved AECD of the type discussed above in
Section III.D. Where a vehicle is chassis-certified and either sold as
an incomplete vehicle to a truck body manufacturer or built and sold as
a complete vehicle, only those sold and built as emergency vehicles
will be eligible to obtain an approved AECD of the type discussed
above.
(2) Certified Engines and Vehicles In-Use
    To address in-use engines and vehicles, EPA plans to allow engine
and vehicle manufacturers to submit requests for EPA approval of
Emergency Vehicle Field Modifications (EVFMs) for on-highway emergency
vehicles and Emergency Equipment Field Modifications (EEFMs) for
nonroad emergency equipment. EVFMs and EEFMs will be modifications to
existing hardware and software to be installed on in-use vehicles or
equipment to prevent loss of speed, torque, or power due to abnormal
conditions of emission control systems, or to prevent such abnormal
conditions from occurring, during vehicle or equipment operation
related to emergency response. EPA will use an approval process similar
to the process that is currently utilized to submit modifications to
current applications for certification, also known as ``running
changes.'' The information submitted by a manufacturer to EPA as part
of this request and approval process will be similar to the information
submitted for emergency vehicle or equipment AECD's.
    It is important to emphasize that this action will allow only those
approved modifications to be deployed by manufacturers and their
authorized dealers. Modifications made by end users are not generally
approvable; rather the tampering prohibitions would generally apply to
such modifications.
    EPA has identified three types of field modifications that will be
permitted for emergency vehicles and emergency equipment under the
final regulations, based on the extent to which the modification is
being incorporated into new production vehicles and equipment. The
three types are:
    [squ] Type A: Any field modification that is a change to a
certified vehicle (i.e., a vehicle, engine or equipment covered by a
certificate of conformity) that is identical in all respects to a
running change that is approved for incorporation in new vehicles by
the manufacturer. Where the running change was approved by EPA for
implementation only in conjunction with certain other running changes,
the field modification may be considered to be a Type A field
modification only if implemented under the same constraints.
    [squ] Type B: Any field modification that is not identical in all
respects to, but provides for essentially the same purpose as, a
running change that is being incorporated in new vehicles by the
manufacturer or that would have been incorporated if the vehicle were
still in production. A Type B field modification is used when it is not
practical to incorporate the exact running change in vehicles that have
left the assembly line, or when the vehicles are no longer in
production.
    [squ] Type C: Any field modification that is made selectively only
to vehicles which have left the assembly line and which would not have
been incorporated on the assembly line. For example, this would apply
when making a field modification to a vehicle that is no longer in
production where there are no similar vehicles in production.
    The amount of justification needed for the field modification
differs depending on which type of modification is being requested.
(3) Labeling Requirements
    Because the engines and vehicles eligible for the AECD's described
in this proposal belong to broadly certified engine families and test
groups, when they are sold for installation in an emergency vehicle and
equipped with one or more approved emergency vehicle AECD's, they must
be labeled as such, to distinguish them from other certified engines.
EPA is proposing adding a labeling requirement to 40 CFR part 86
subpart A, such that engines with one or more approved AECD's for
emergency vehicle applications must be labeled with the statement:
``THIS ENGINE IS FOR INSTALLATION IN EMERGENCY VEHICLES ONLY.'' EPA is
also proposing adding a labeling requirement to 40 CFR part 86 subpart
S, such that vehicles with one or more approved AECD's for emergency
vehicles, include the following statement on the emission control
information label: ``THIS VEHICLE HAS A LIMITED EXEMPTION AS AN
EMERGENCY VEHICLE.'' EPA is also adding a labeling requirement to 40
CFR part 1039, such that nonroad engines with one or more approved
AECD's for emergency equipment include a label with the following
statement: ``THIS ENGINE IS FOR INSTALLATION IN EMERGENCY EQUIPMENT
ONLY.''
    EPA requests comment on whether these labeling requirements are
satisfactory to ensure that engines and vehicles operating with
approved emergency AECD's are permanently distinguished from similar
certified engines. EPA also requests comment on whether a similar label
should be required for an in-use emergency vehicle or equipment where a
field modification is deployed that prevents the engine from losing
speed, torque, or power due to any occurrences of abnormal conditions
of the emission control system, or prevents such abnormal conditions
from occurring.

(4) Other Regulatory Provisions
    Today's rule will not alter the tampering prohibition in 40 CFR
1068.101(b)(1). This provision describes a general prohibition against
anyone from removing or rendering inoperative an engine's emission
controls before or after entering into service, where an exception is
provided in 1068.101(b)(1)(ii) for engine modifications needed to
respond to a temporary emergency, provided that the engine is restored
to proper functioning as soon as possible after the emergency has
passed. EPA encourages manufacturers to design their emergency vehicle
AECD's to be engaged only to the extent necessary to prevent the engine
from losing speed, torque, or power due to abnormal conditions of the
emission control system, or to prevent such abnormal conditions from
occurring during operation related to emergency response. EPA
recognizes that there may be cases where an AECD may need to be engaged
at times other than while actively responding to an emergency, in order
to assure that loss of speed, torque or power does not occur during
operation related to emergency response. EPA also recognizes that some
AECD's may involve electronic approaches where the engine's functions
would be modulated based on exhaust backpressure or other parameters
that are not correlated with any emergency situation. EPA may even, in
extreme cases, such as at high altitude or with certain older MY
engines allow engagement of AECD's at all times, if they are justified
as necessary to prevent engine from losing speed, torque, or power
during operation related to emergency response.
    We are also encouraging manufacturers to design their emission
control systems to discourage tampering. According to EPA's tampering
prohibition, a vehicle operator who abuses or alters an approved AECD
may be guilty of tampering. For example, if an AECD includes enabling
an operator to initiate more frequent manual active regenerations,
engine manufacturers may choose to prevent the abuse of this function
by means such as a daily or weekly cap on the number of manual active
regenerations, or a minimum soot loading for the function to engage. As
another example, if an emergency vehicle alerts a driver to an abnormal
condition of its emission control system by illuminating dash lamps,
alarms or other warnings that do not limit vehicle performance, it is
the operator's responsibility to take prompt action to remedy the
problem.\24\ If an operator disregards such warnings beyond the time
needed to respond to the emergency, this may be considered tampering.
It is important to note that if an emergency vehicle is not equipped to
ever allow an operator to initiate a manual active regeneration, this
may in practice encourage tampering by the end user.
---------------------------------------------------------------------------

    \24\ Although this action will not affect certification of
engine families or test groups, EPA's regulations do offer options
to manufacturers who wish to ensure that emission-related
maintenance will occur in use, including visible signals that are
not reset until maintenance occurs. 40 CFR 86.004-25(b)(6)(ii).
---------------------------------------------------------------------------

    Manufacturers of highway and nonroad engines will be required to
describe any emergency vehicle AECD in an application for
certification. In this action, we are not proposing any revisions to
the information needed to review and approve AECD's. It is common
practice for manufacturers, in describing AECD's, to identify engine
parameters such as those that would operate differently to preserve
adequate engine performance during an emergency, including information
about how the engine would respond under different in-use operating
conditions under the various sets of conditions that would otherwise
cause the engine to operate at less than full performance levels. Other
than the requirement for a manufacturer to describe the emergency
vehicle AECD in its application for certification, we do not expect
this provision to be relevant for other aspects of certification. For
example, emissions certification testing may be conducted with any
approved AECD's for emergency vehicle or equipment deactivated.
Additionally, manufacturers do not need to consider emergency vehicle
AECD's when developing infrequent regeneration adjustment factors
(IRAFs) or when developing deterioration factors (DFs). Thus,
manufacturers can include emergency and non-emergency engines and
vehicles in the same engine families and test groups. Manufacturers may
also apply for emergency vehicle AECD's for new, existing, and/or
formerly approved emissions certificates.

F. Economic Impacts

    EPA expects the economic effects of this rule to be small, and to
potentially have benefits that are a natural result of easing
constraints.
(1) Costs to Manufacturers
    Due to the optional and voluntary nature of this action, there are
no direct regulatory compliance costs to engine manufacturers. To the
extent manufacturers elect to develop and deploy upgrades to engines
for emergency vehicles, they may voluntarily incur some degree of costs
associated with the following:
     Design and testing to determine effectiveness of potential
AECDs
     Education & outreach to intermediate vehicle manufacturers
and end users
     Deployment of AECDs onto new and in-use emergency vehicles
     Labeling costs
    EPA expects any fixed costs will be small, and any variable costs
will apply only to the engines sold for installation in emergency
vehicles or emergency equipment, which comprise less than one percent
of the heavy-duty on-road fleet, and an even smaller fraction of the
nonroad fleet. As per standard practice, manufacturers would be free to
set a fair market price for any approved AECD they offer, to offset the
costs incurred in its development.
(2) Operational Costs
    Depending on the type of AECD or field modification that a
manufacturer voluntarily elects to deploy, some operational costs could
increase and some could decrease.
    When an emergency vehicle is experiencing frequent plugging of its
DPF, this increases maintenance costs for owners and warranty costs for
manufacturers. These costs are expected to decrease with this action.
Furthermore, EPA believes that the potential for reduced warranty costs
may help to offset the cost to produce and deploy any optional AECD's.
Similarly, EPA believes the potential for reduced maintenance and
operational costs may offset the cost to owners for obtaining requested
AECD's.
    Where DPF systems employ fuel dosing to enable active automatic
regenerations, it is uncertain whether liberalizing the parameters for
initiating regenerations would affect fuel consumption, and whether
fuel consumption would increase with an increased number of
regenerations during a given operating period. To the extent
regenerations are enabled with other means besides fuel, or demand for
regenerations is reduced through recalibration, then any potential
increase in fuel use from dosing would be mitigated. Further discussion
of operational costs including costs of fuel dosing is provided in the
Notice of Proposed Rulemaking published elsewhere in Today's Federal
Register.

(3) Societal Costs
    Because this rule eases constraints on the development of robust
DPF systems, the economic impacts can only improve with this action. It
is presumed that the benefits to society of enabling first responders
to act quickly when needed outweigh the costs to society of the
temporary increase in emissions from this small segment of vehicles.

G. Environmental Impacts

    We expect any environmental impacts from this action will be small.
By promulgating these amendments, it is expected that the emissions
from this segment of the heavy-duty fleet will not change
significantly.
    EPA estimates that on-road emergency vehicles comprise less than
one percent of the national heavy-duty fleet. According to the
International Council on Clean Transportation (ICCT), less than one
percent of all new heavy-duty truck registrations in 2003 to 2007 were
for emergency vehicles (includes class 8 fire trucks plus other class
3-8 emergency vehicles).\25\ On average, the ICCT's data suggest that
approximately 5,700 new emergency vehicles are sold in the U.S. each
year; about 0.8 percent of the 3.4 million new heavy-duty trucks
registered between 2003 and 2007. The available information indicates
that the emergency vehicles included in the scope of this rulemaking
have lower annual vehicle miles traveled than average non-emergency
vehicles. Therefore, we conclude that they contribute less than 1% of
the annual air emissions from the heavy-duty diesel truck fleet.
---------------------------------------------------------------------------

    \25\ ICCT, May 2009, ``Heavy-Duty Vehicle Market Analysis:
Vehicle Characteristics & Fuel Use, Manufacturer Market Shares.''
---------------------------------------------------------------------------

    Due to the optional and voluntary nature of this action, it is
difficult to estimate its overall emissions impact accurately. The
amendments offer many options to manufacturers, and the emissions
impacts will depend on which options and strategies are employed, and
for how many vehicles. Further discussions of potential NOX
and PM emissions impacts and fuel consumption from dosing are provided
in the Notice of Proposed Rulemaking published elsewhere in Today's
Federal Register.

H. Health Effects

    EPA's clean diesel standards are already providing substantial
benefits to public health and welfare and the environment through
significant reductions in emissions of NOX, PM, nonmethane
hydrocarbons (NMHC), carbon monoxide, sulfur oxides (SOX),
and air toxics. We project that by 2030, the on-highway program alone
will reduce annual emissions of NOX, NMHC, and PM by 2.6
million, 115,000 and 109,000 tons, respectively. These emission
reductions will prevent 8,300 premature deaths, over 9,500
hospitalizations, and 1.5 million work days lost. All told, the
monetized benefits of the on-highway rule plus the nonroad diesel Tier
4 rule total over $150 billion. A sizeable part of the benefits in the
early years of these programs has come from large reductions in the
amount of direct and secondary PM emitted by the existing fleet of
heavy-duty engines and vehicles, by requiring the use of the higher
quality diesel fuel in these vehicles. While this final action may
slightly increase some emissions, as explained in the previous section,
we do not expect that these small increases will significantly diminish
the health benefits of our stringent clean diesel standards.

IV. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    This action is not a ``significant regulatory action'' under the
terms of Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and
is therefore not subject to review under Executive Orders 12866 and
13563 (76 FR 3821, January 21, 2011).

B. Paperwork Reduction Act

    This action does not impose any new information collection burden.
The regulatory relief for emergency vehicles is voluntary and optional,
and the revisions for engine and vehicle maintenance merely codify
existing guidelines. However, the Office of Management and Budget (OMB)
has previously approved the information collection requirements
contained in the existing regulations under the provisions of the
Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and has assigned OMB
Control Numbers 2060-0104 and 2060-0287. The OMB control numbers for
EPA's regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of this rule on small
entities, small entity is defined as: (1) A small business primarily
engaged in shipbuilding and repairing as defined by NAICS code 336611
with 1,000 or fewer employees (based on Small Business Administration
size standards); (2) a small business that is primarily engaged in
freight or passenger transportation on the Great Lakes as defined by
NAICS codes 483113 and 483114 with 500 or fewer employees (based on
Small Business Administration size standards); (3) a small business
primarily engaged in commercial and industrial machinery and equipment
repair and maintenance as defined by NAICS code 811310 with annual
receipts less than $7 million (based on Small Business Administration
size standards); (4) a small governmental jurisdiction that is a
government of a city, county, town, school district or special district
with a population of less than 50,000; and (5) a small organization
that is any not-for-profit enterprise which is independently owned and
operated and is not dominant in its field.
    After considering the economic impacts of today's rule on small
entities, I certify that this final rule will not have a significant
economic impact on a substantial number of small entities.
    In determining whether a rule has a significant economic impact on
a substantial number of small entities, the impact of concern is any
significant adverse economic impact on small entities, since the
primary purpose of the regulatory flexibility analyses is to identify
and address regulatory alternatives ``which minimize any significant
economic impact of the rule on small entities.'' 5 U.S.C. 603 and 604.
Thus, an agency may certify that a rule will not have a significant
economic impact on a substantial number of small entities if the rule
relieves regulatory burden, or otherwise has a positive economic effect
on all of the small entities subject to the rule.
    This rule provides regulatory relief related to emergency vehicles.
As such, we anticipate no costs and therefore no regulatory burden
associated with this rule. We have concluded that this rule will not
increase regulatory burden for affected small entities.

D. Unfunded Mandates Reform Act

    This action contains no Federal mandates under the provisions of
Title II of the Unfunded Mandates Reform

Act of 1995 (UMRA), 2 U.S.C. 1531-1538 for State, local, or tribal
governments or the private sector. The action imposes no enforceable
duty on any State, local or tribal governments or the private sector.
This direct final rule offers manufacturers the flexibility to choose
whether to use optional AECD's based on their strategies for complying
with the applicable emissions standards. Therefore, this action is not
subject to the requirements of sections 202 or 205 of the UMRA.
    This action is also not subject to the requirements of section 203
of UMRA because it contains no regulatory requirements that might
significantly or uniquely affect small governments.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government, as
specified in Executive Order 13132. This direct final rule applies to
manufacturers of heavy-duty diesel engines and not to state or local
governments. Thus, Executive Order 13132 does not apply to this action.

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

    This action does not have tribal implications, as specified in
Executive Order 13175 (65 FR 67249, November 9, 2000). This direct
final rule will be implemented at the Federal level and may result in
indirect costs on affected engine manufacturers depending on the extent
to which they take advantage of the flexibilities offered. Tribal
governments will be affected only to the extent they purchase and use
vehicles with regulated engines. Thus, Executive Order 13175 does not
apply to this action.

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

    Executive Order 13045: ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under Executive Order 12866, and (2) concerns an
environmental health or safety risk that EPA has reason to believe may
have a disproportionate effect on children. If the regulatory action
meets both criteria, the agency must evaluate the environmental health
or safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the agency.
    EPA interprets Executive Order 13045 as applying only to those
regulatory actions that are based on health or safety risks, such that
the analysis required under section 5-501 of the Order has the
potential to influence the regulation. This direct final rule is not
subject to Executive Order 13045 because it does not establish an
environmental standard intended to mitigate health or safety risks, and
because it is not economically significant under Executive Order 12866.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355
(May 22, 2001)), because it is not a significant regulatory action
under Executive Order 12866.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards in its regulatory
activities unless to do so would be inconsistent with applicable law or
otherwise impractical. Voluntary consensus standards are technical
standards (e.g., materials specifications, test methods, sampling
procedures, and business practices) that are developed or adopted by
voluntary consensus standards bodies. NTTAA directs EPA to provide
Congress, through OMB, explanations when the Agency decides not to use
available and applicable voluntary consensus standards.
    This action does not involve technical standards. Therefore, EPA
did not consider the use of any voluntary consensus standards.

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

    Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes
federal executive policy on environmental justice. Its main provision
directs federal agencies, to the greatest extent practicable and
permitted by law, to make environmental justice part of their mission
by identifying and addressing, as appropriate, disproportionately high
and adverse human health or environmental effects of their programs,
policies, and activities on minority populations and low-income
populations in the United States.
    EPA has determined that this direct final rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations. This action is not
expected to have any adverse environmental impacts.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A Major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2). This rule will be effective on August 7, 2012.

List of Subjects

40 CFR Part 85

    Confidential business information, Imports, Labeling, Motor vehicle
pollution, Reporting and recordkeeping requirements, Research,
Warranties.

40 CFR Part 86

    Administrative practice and procedure, Confidential business
information, Motor vehicle pollution, Reporting and recordkeeping
requirements.

40 CFR Part 1039

    Environmental protection, Administrative practice and procedure,
Air pollution control, Confidential business information, Imports,
Labeling, Penalties, Reporting and recordkeeping requirements,
Warranties.

    Dated: May 23, 2012.
Lisa P. Jackson,
Administrator.

    For the reasons set forth in the preamble, the Environmental
Protection Agency amends title 40, chapter I of the Code of Federal
Regulations as follows:

PART 85--CONTROL OF AIR POLLUTION FROM MOBILE SOURCES

0
1. The authority citation for part 85 continues to read as follows:

    Authority:  42 U.S.C. 7401-7671q.

Subpart R--[Amended]

0
2. Add Sec.  85.1716 to subpart R to read as follows:

Sec.  85.1716  Approval of an emergency vehicle field modification
(EVFM).

    This section describes how you may implement design changes for an
emergency vehicle that has already been placed into service to ensure
that the vehicle will perform properly in emergency situations. This
applies for any light-duty vehicle, light-duty truck, or heavy-duty
vehicle meeting the definition of emergency vehicle in 40 CFR 86.004-2
or 86.1803. In this section, ``you'' refers to the certifying
manufacturer and ``we'' refers to the EPA Administrator and any
authorized representatives.
    (a) You must notify us in writing of your intent to install or
distribute an emergency vehicle field modification (EVFM). In some
cases you may install or distribute an EVFM only with our advance
approval, as specified in this section.
    (b) Include in your notification a full description of the EVFM and
any documentation to support your determination that the EVFM is
necessary to prevent the vehicle from losing speed, torque, or power
due to abnormal conditions of its emission control system, or to
prevent such abnormal conditions from occurring during operation
related to emergency response. Examples of such abnormal conditions may
include excessive exhaust backpressure from an overloaded particulate
trap, or running out of diesel exhaust fluid for engines that rely on
urea-based selective catalytic reduction. Your determination must be
based on an engineering evaluation or testing or both.
    (c) You may need our advance approval for your EVFM, as follows:
    (1) Where the proposed EVFM is identical to an AECD we approved
under this part for an engine family currently in production, no
approval of the proposed EVFM is necessary.
    (2) Where the proposed EVFM is for an engine family currently in
production but the applicable demonstration is based on an AECD we
approved under this part for an engine family no longer in production,
you must describe to us how your proposed EVFM differs from the
approved AECD. Unless we say otherwise, your proposed EVFM is deemed
approved 30 days after you notify us.
    (3) If we have not approved an EVFM comparable to the one you are
proposing, you must get our approval before installing or distributing
it. In this case, we may request additional information to support your
determination under paragraph (b) of this section, as follows:
    (i) If we request additional information and you do not provide it
within 30 days after we ask, we may deem that you have retracted your
request for our approval; however, we may extend this deadline for
submitting the additional information.
    (ii) We will deny your request if we determine that the EVFM is not
necessary to prevent the vehicle from losing speed, torque, or power
due abnormal conditions of the emission control system, or to prevent
such abnormal conditions from occurring, during operation related to
emergency response.
    (iii) Unless we say otherwise, your proposed EVFM is deemed
approved 30 days after we acknowledge that you have provided us with
all the additional information we have specified.
    (4) If your proposed EVFM is deemed to be approved under paragraph
(c)(2) or (3) of this section and we find later that your EVFM in fact
does not meet the requirements of this section, we may require you to
no longer install or distribute it.

PART 86--CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES
AND ENGINES

0
3. The authority citation for part 86 continues to read as follows:

    Authority:  42 U.S.C. 7401-7671q.

Subpart A--[Amended]

0
4. Section 86.004-2 is amended as follows:
0
a. By adding a definition for ``Ambulance'' in alphabetical order.
0
b. By revising the definition for ``Defeat device''.
0
c. By adding definitions for ``Diesel exhaust fluid'', ``Emergency
vehicle'', and ``Fire truck'' in alphabetical order.
    The additions and revision read as follows:

Sec.  86.004-2  Definitions.

* * * * *
    Ambulance has the meaning given in Sec.  86.1803.
    Defeat device means an auxiliary emission control device (AECD)
that reduces the effectiveness of the emission control system under
conditions which may reasonably be expected to be encountered in normal
vehicle operation and use, unless:
    (1) Such conditions are substantially included in the applicable
Federal emission test procedure for heavy-duty vehicles and heavy-duty
engines described in subpart N of this part;
    (2) The need for the AECD is justified in terms of protecting the
vehicle against damage or accident;
    (3) The AECD does not go beyond the requirements of engine
starting; or
    (4) The AECD applies only for engines that will be installed in
emergency vehicles, and the need is justified in terms of preventing
the engine from losing speed, torque, or power due abnormal conditions
of the emission control system, or in terms of preventing such abnormal
conditions from occurring, during operation related to emergency
response. Examples of such abnormal conditions may include excessive
exhaust backpressure from an overloaded particulate trap, and running
out of diesel exhaust fluid for engines that rely on urea-based
selective catalytic reduction.
    Diesel exhaust fluid (DEF) has the meaning given in Sec.  86.1803.
    Emergency vehicle means a vehicle that is an ambulance or a fire
truck.
    Fire truck has the meaning given in Sec.  86.1803.
* * * * *

0
5. Section 86.004-28 is amended by revising paragraph (i) introductory
text to read as follows:

Sec.  86.004-28  Compliance with emission standards.

* * * * *
    (i) Emission results from heavy-duty engines equipped with exhaust
aftertreatment may need to be adjusted to account for regeneration
events. This provision only applies for engines equipped with emission
controls that are regenerated on an infrequent basis. For the purpose
of this paragraph (i), the term ``regeneration'' means an event during
which emission levels change while the aftertreatment performance is
being restored by design. Examples of regenerations are increasing
exhaust gas temperature to remove sulfur from an adsorber or increasing
exhaust gas temperature to oxidize PM in a trap. For the purpose of
this paragraph (i), the term ``infrequent'' means having an expected
frequency of less than once per transient test cycle. Calculation and
use of adjustment factors are described in paragraphs (i)(1) through
(5) of this section. If your engine family includes engines with one or
more AECDs for emergency vehicle applications approved under paragraph
(4) of the definition of defeat device, do not consider additional
regenerations resulting from those AECDs when

calculating emission factors or frequencies under this paragraph (i).
* * * * *

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6. Section 86.095-35 is amended by revising paragraph (a)(3)(iii)(O) to
read as follows:

Sec.  86.095-35  Labeling.

    (a) * * *
    (3) * * *
    (iii) * * *
    (O) For engines with one or more approved AECDs for emergency
vehicle applications under paragraph (4) of the definition of ``defeat
device'' in Sec.  86.004-2, the statement: ``THIS ENGINE IS FOR
INSTALLATION IN EMERGENCY VEHICLES ONLY.''
* * * * *

Subpart B--[Amended]

0
7. Section 86.131-00 is amended by adding paragraph (g) to read as
follows:

Sec.  86.131-00  Vehicle preparation.

    (g) You may disable any AECDs that have been approved solely for
emergency vehicle applications under paragraph (4) of the definition of
defeat device. The emission standards do not apply when any of these
AECDs are active.

Subpart N--[Amended]

0
8. Section 86.1305-2010 is amended by adding paragraph (i) to read as
follows:

Sec.  86.1305-2010  Introduction; structure of subpart.

* * * * *
    (i) You may disable any AECDs that have been approved solely for
emergency vehicle applications under paragraph (4) of the definition of
``defeat device'' in Sec.  86.004-2. The emission standards do not
apply when any of these AECDs are active.

0
9. Section 86.1370-2007 is amended by adding paragraph (h) to read as
follows:

Sec.  86.1370-2007  Not-To-Exceed test procedures.

* * * * *
    (h) Emergency vehicle AECDs. If your engine family includes engines
with one or more approved AECDs for emergency vehicle applications
under paragraph (4) of the definition of ``defeat device'' in Sec.
86.1803, the NTE emission limits do not apply when any of these AECDs
are active.

Subpart S--[Amended]

0
10. Section 86.1803-01 is amended as follows:
0
a. By adding a definition for ``Ambulance'' in alphabetical order.
0
b. By revising the definition for ``Defeat device''.
0
c. By adding definitions for ``Diesel exhaust fluid'', ``Emergency
vehicle'', and ``Fire truck'' in alphabetical order.

Sec.  86.1803-01  Definitions.

* * * * *
    Ambulance means a vehicle used for emergency medical care that
provides all of the following:
    (1) A driver's compartment.
    (2) A patient compartment to accommodate an emergency medical
services provider and one patient located on the primary cot so
positioned that the primary patient can be given intensive life-support
during transit.
    (3) Equipment and supplies for emergency care at the scene as well
as during transport.
    (4) Safety, comfort, and avoidance of aggravation of the patient's
injury or illness.
    (5) Two-way radio communication.
    (6) Audible and visual traffic warning devices.
* * * * *
    Defeat device means an auxiliary emission control device (AECD)
that reduces the effectiveness of the emission control system under
conditions which may reasonably be expected to be encountered in normal
vehicle operation and use, unless:
    (1) Such conditions are substantially included in the Federal
emission test procedure;
    (2) The need for the AECD is justified in terms of protecting the
vehicle against damage or accident;
    (3) The AECD does not go beyond the requirements of engine
starting; or
    (4) The AECD applies only for emergency vehicles and the need is
justified in terms of preventing the vehicle from losing speed, torque,
or power due to abnormal conditions of the emission control system, or
in terms of preventing such abnormal conditions from occurring, during
operation related to emergency response. Examples of such abnormal
conditions may include excessive exhaust backpressure from an
overloaded particulate trap, and running out of diesel exhaust fluid
for engines that rely on urea-based selective catalytic reduction.
* * * * *
    Diesel exhaust fluid (DEF) means a liquid compound used in
conjunction with selective catalytic reduction to reduce NOX
emissions. Diesel exhaust fluid is generally understood to conform to
the specifications of ISO 22241.
* * * * *
    Emergency vehicle means a vehicle that is an ambulance or a fire
truck.
* * * * *
    Fire truck means a vehicle designed to be used under emergency
conditions to transport personnel and equipment and to support the
suppression of fires and mitigation of other hazardous situations.
* * * * *

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11. Section 86.1807-01 is amended by adding paragraphs (h) and (i) to
read as follows:

Sec.  86.1807-01  Vehicle labeling.

* * * * *
    (h) Vehicles powered by model year 2007 through 2013 diesel-fueled
engines must include permanent readily visible labels on the dashboard
(or instrument panel) and near all fuel inlets that state ``Use Ultra
Low Sulfur Diesel Fuel Only'' or ``Ultra Low Sulfur Diesel Fuel Only''.
    (i) For vehicles with one or more approved AECDs for emergency
vehicles under paragraph (4) of the definition of ``defeat device'' in
Sec.  86.1803, include the following statement on the emission control
information label: ``THIS VEHICLE HAS A LIMITED EXEMPTION AS AN
EMERGENCY VEHICLE.''

Sec.  86.1807-07  [Removed]

0
12. Subpart S is amended by removing Sec.  86.1807-07.

0
13. Section 86.1840-01 is amended by revising paragraph (c) to read as
follows:

Sec.  86.1840-01  Special test procedures.

* * * * *
    (c) Manufacturers of vehicles equipped with periodically
regenerating aftertreatment devices must propose a procedure for
testing and certifying such vehicles, including SFTP testing, for the
review and approval of the Administrator. The manufacturer must submit
its proposal before it begins any service accumulation or emission
testing. The manufacturer must provide with its submittal sufficient
documentation and data for the Administrator to fully evaluate the
operation of the aftertreatment devices and the proposed certification
and testing procedure.
* * * * *

PART 1039--CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD
COMPRESSION-IGNITION ENGINES

0
14. The authority citation for part 1039 continues to read as follows:

    Authority:  42 U.S.C. 7401-7671q.

Subpart B--[Amended]

0
15. Section 1039.115 is amended by adding paragraphs (g)(4) and (5) to
read as follows:

Sec.  1039.115  What other requirements apply?

* * * * *
    (g) * * *
    (4) The auxiliary emission control device applies only for engines
that will be installed in emergency equipment and the need is justified
in terms of preventing the equipment from losing speed or power due to
abnormal conditions of the emission control system, or in terms of
preventing such abnormal conditions from occurring, during operation
related to emergency response. Examples of such abnormal conditions may
include excessive exhaust backpressure from an overloaded particulate
trap, and running out of diesel exhaust fluid for engines that rely on
urea-based selective catalytic reduction. The emission standards do not
apply when any AECDs approved under this paragraph (g)(4) are active.
    (5) The auxiliary emission control device operates only in
emergency situations as defined in Sec.  1039.665 and meets all of the
requirements of that section, and you meet all of the requirements of
that section.

0
16. Section 1039.135 is amended by adding paragraph (c)(15) to read as
follows:

Sec.  1039.135  How must I label and identify the engines I produce?

* * * * *
    (c) * * *
    (15) For engines with one or more approved auxiliary emission
control devices for emergency equipment applications under Sec.
1039.115(g)(4), the statement: ``THIS ENGINE IS FOR INSTALLATION IN
EMERGENCY EQUIPMENT ONLY.''
* * * * *

Subpart F--[Amended]

0
17.Section 1039.501 is amended by adding paragraph (g) to read as
follows:

Sec.  1039.501  How do I run a valid emission test?

* * * * *
    (g) You may disable any AECDs that have been approved solely for
emergency equipment applications under Sec.  1039.115(g)(4).

0
18.Section 1039.525 is amended by revising the introductory text to
read as follows:

Sec.  1039.525  How do I adjust emission levels to account for
infrequently regenerating aftertreatment devices?

    This section describes how to adjust emission results from engines
using aftertreatment technology with infrequent regeneration events.
For this section, ``regeneration'' means an intended event during which
emission levels change while the system restores aftertreatment
performance. For example, exhaust gas temperatures may increase
temporarily to remove sulfur from adsorbers or to oxidize accumulated
particulate matter in a trap. For this section, ``infrequent'' refers
to regeneration events that are expected to occur on average less than
once over the applicable transient duty cycle or ramped-modal cycle, or
on average less than once per typical mode in a discrete-mode test. If
your engine family includes engines with one or more AECDs for
emergency equipment applications approved under Sec.  1039.115(g)(4),
do not consider additional regenerations resulting from those AECDs
when calculating emission factors or frequencies under this section.
* * * * *

Subpart G--[Amended]

0
19. Add Sec.  1039.670 to subpart G to read as follows:

Sec.  1039.670  Approval of an emergency equipment field modification
(EEFM).

    This section describes how you may implement design changes for
emergency equipment that has already been placed into service to ensure
that the equipment will perform properly in emergency situations.
    (a) You must notify us in writing of your intent to install or
distribute an emergency equipment field modification (EEFM). In some
cases you may install or distribute an EEFM only with our advance
approval, as specified in this section.
    (b) Include in your notification a full description of the EEFM and
any documentation to support your determination that the EEFM is
necessary to prevent the equipment from losing speed, torque, or power
due to abnormal conditions of its emission control system, or to
prevent such abnormal conditions from occurring during operation
related to emergency response. Examples of such abnormal conditions may
include excessive exhaust backpressure from an overloaded particulate
trap, or running out of diesel exhaust fluid (DEF) for engines that
rely on urea-based selective catalytic reduction. Your determination
must be based on an engineering evaluation or testing or both.
    (c) You may need our advance approval for your EEFM, as follows:
    (1) Where the proposed EEFM is identical to an AECD we approved
under this part for an engine family currently in production, no
approval of the proposed EEFM is necessary.
    (2) Where the proposed EEFM is for an engine family currently in
production but the applicable demonstration is based on an AECD we
approved under this part for an engine family no longer in production,
you must describe to us how your proposed EEFM differs from the
approved AECD. Unless we say otherwise, your proposed EEFM is deemed
approved 30 days after you notify us.
    (3) If we have not approved an EEFM comparable to the one you are
proposing, you must get our approval before installing or distributing
it. In this case, we may request additional information to support your
determination under paragraph (b) of this section, as follows:
    (i) If we request additional information and you do not provide it
within 30 days after we ask, we may deem that you have retracted your
request for our approval; however, we may extend this deadline for
submitting the additional information.
    (ii) We will deny your request if we determine that the EEFM is not
necessary to prevent the equipment from losing speed, torque, or power
due abnormal conditions of the emission control system, or to prevent