```

[Federal Register Volume 77, Number 111 (Friday, June 8, 2012)]
[Proposed Rules]
[Pages 34149-34178]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-13087]

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

[[Page 34149]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 85, 86, and 1039

[EPA-HQ-OAR-2011-1032; FRL-9673-2]
RIN 2060-AR46

Heavy-Duty Highway Program: Revisions for Emergency Vehicles and 
SCR Maintenance

AGENCY:  Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking.

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SUMMARY:  This proposal consists of three parts. First, EPA is 
proposing revisions to its heavy-duty diesel regulations that would 
enable emergency vehicles, such as dedicated ambulances and fire 
trucks, to perform their 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 would 
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. Second, EPA is proposing to revise the 
emission-related maintenance and scheduled maintenance intervals for 
all motor vehicles and nonroad compression-ignition engines to specify 
minimum maintenance intervals for replenishment of consumable chemical 
reductant in connection with the use of selective catalytic reduction 
technologies. Third, EPA is proposing to offer short-term relief for 
nonroad engines from performance inducements related to the emission 
control system, for general purpose nonroad vehicles while operating in 
temporary emergency service. These actions are not expected to result 
in any significant changes in regulatory burdens or costs.

DATES: Comments on all aspects of this proposal must be received on or 
before July 27, 2012. See the SUPPLEMENTARY INFORMATION section on 
``Public Participation'' for more information about written comments.
    Public Hearings: EPA will hold a public hearing on Wednesday, June 
27, 2012 in Ann Arbor, Michigan. The hearing will start at 10 a.m. 
local time and will continue until everyone has had a chance to speak. 
For more information about the public hearing, see ``How Do I 
Participate in the Public Hearing?'' under the SUPPLEMENTARY 
INFORMATION section on ``Public Participation'' below at Section 
VIII.B.

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: a-and-r-docket@epa.gov.
     Fax: (202) 566-9744.
     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-2011-1032. 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'' 
below at Section VIII.A.
    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., confidential business 
information or other information whose disclosure is restricted by 
statute. Certain other material, such as copyrighted material, will be 
publicly available only in hard copy in the docket. Publicly available 
docket materials are available either electronically in 
www.regulations.gov or in hard copy at the 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 (202) 566-1744, and the telephone number for the Air 
Docket is (202) 566-1742.

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: 734-214-4788; fax number: 734-214-4816; email 
address: steele.lauren (@epa.gov).

SUPPLEMENTARY INFORMATION:

Does this action apply to me?

    This proposed action would 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. You 
may also be affected by this action if you manufacture diesel engines 
that make use of a consumable chemical reductant to comply with 
emissions standards for nitrogen oxides. You may also be affected by 
this action if you produce or import diesel engines for nonroad 
applications. The following table gives some examples of entities that 
may be affected by this proposed action. Because these are only 
examples, you should carefully examine the proposed and existing 
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.

------------------------------------------------------------------------
                                   NAICS Codes   Examples of potentially
            Category                   \a\          regulated entities
------------------------------------------------------------------------
Industry.......................          336111  Engine and Truck
                                         336112   Manufacturers
                                         333618
                                         336120
Industry.......................          541514  Commercial Importers of
                                         811112   Vehicles and Vehicle
                                         811198   Components
Industry.......................          811310  Engine Repair,
                                                  Remanufacture, and
                                                  Maintenance
------------------------------------------------------------------------
Note:
\a\ North American Industry Classification System (NAICS).

[[Page 34150]]

Table of Contents

I. Overview
    A. Emergency Vehicle Provisions
    B. Diesel Exhaust Fluid Provisions
    C. Nonroad Equipment Used Temporarily in Emergency Service
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. Direct Final Rule
IV. Emergency Vehicle Provisions
    A. Background on Regulation of Emergency Vehicles
    B. Current Provisions for Other Emergency Vehicles and Engines
    C. 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?
    D. 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
    E. Proposed Regulatory Action
    (1) Liberalized Regeneration Requests
    (2) Engine Recalibration
    (3) Backpressure Relief
    F. What engines and vehicles would be affected?
    (1) Newly Certified Engines and Vehicles
    (2) Certified Engines and Vehicles In-Use
    (3) Labeling Requirements
    (4) Other Regulatory Provisions
V. Scheduled Maintenance and Maintenance Interval for Replacement of 
Diesel Exhaust Fluid
    A. Background
    B. Proposed Regulatory Action
    (1) Scheduled Emission-Related Maintenance
    (2) Maintenance Intervals for On-Highway Diesel Engines
    (3) Maintenance Intervals for Nonroad Compression-Ignition 
Engines
VI. Nonroad Engines in Temporary Emergency Service
    A. Use of Nonroad Engines in Emergency Situations
    B. Proposed Regulatory Action
    (1) General Requirements
    (2) Approval Criteria
    (3) Allowable Use of Emergency AECD's
VII. Economic, Environmental, and Health Impacts of Proposed Rule
    A. Economic Impacts
    (1) Economic Impacts of Emergency Vehicle Proposal
    (2) Economic impacts of SCR Maintenance Proposal
    (3) Economic Impacts for Nonroad Engines Used in Emergency 
Situations
    B. Environmental Impacts
    (1) Environmental Impacts of Emergency Vehicle Proposal
    (2) Environmental Impacts of SCR Maintenance Proposal
    (3) Environmental Impacts for Nonroad Engines Used in Emergency 
Situations
    C. Health Effects
VIII. Public Participation
    A. How do I submit comments?
    B. Will there be a public hearing?
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    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: Energy Effects
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. Overview

A. Emergency Vehicle Provisions

    EPA is proposing amendments to its heavy-duty diesel engine 
programs that would 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 
proposing 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.

B. Diesel Exhaust Fluid Provisions

    EPA is proposing to amend its regulations for diesel engines to add 
provisions specifying emission-related maintenance and scheduled 
maintenance intervals for replenishment of consumable chemical 
reductant in connection with engines and vehicles that use selective 
catalytic reduction (SCR) technologies. This would apply to the use of 
SCR with model year (MY) 2011 and later light-duty vehicles and nonroad 
compression ignition (NRCI) engines, and MY 2012 and later heavy-duty 
vehicles and engines.
    Most manufacturers of diesel engines and vehicles subject to our 
current standards regulating oxides of nitrogen (NOX) have 
chosen to use a NOX reduction technology known as selective 
catalytic reduction (SCR) in order to meet these requirements. SCR 
systems use a chemical reductant that usually contains urea and is 
known as diesel exhaust fluid (DEF). The DEF is injected into the 
exhaust gas and requires periodic replenishment by refilling the DEF 
tank.
    Given that SCR use is now common in the transportation sector and 
replenishment of DEF is necessary for SCR to be effective, it is 
appropriate to add DEF replenishment to the list of scheduled emission-
related maintenance published in the Code of Federal Regulations (CFR), 
rather than rely on a case-by-case approval as is specified in the 
current regulations. This action would improve the clarity and 
transparency of EPA's requirements for SCR systems.

C. Nonroad Equipment Used Temporarily in Emergency Service

    EPA is proposing short-term relief from emission control system 
performance inducements for any nonroad compression ignition engine 
powered vehicles operating in temporary emergency service. This relief 
would address concerns about unusual circumstances where performance 
inducements could hinder equipment performance in emergency conditions, 
which are defined as conditions in which the functioning (or 
malfunctioning) of emission controls poses a significant risk to human 
life. We are proposing provisions for a short-term emergency bypass of 
the normal emission controls, including inducement strategies, which 
could result in a loss of power of an engine; thus, allowing the 
equipment to temporarily perform emergency-related work. By this 
action, EPA would help our nation's nonroad equipment perform temporary 
emergency service; to better ensure public safety and welfare and the 
protection of lives.

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

[[Page 34151]]

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).
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \2\ Control of Emissions of Air Pollution from Nonroad Diesel 
Engines and Fuel (69 FR 38958).
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III. Direct Final Rule

    In addition to this notice of proposed rulemaking, EPA is also 
publishing a Direct Final Rule (DFR) addressing the emergency vehicle 
provisions described in Section IV of this document. We are doing this 
to expedite the regulatory process to allow engine and vehicle 
modifications to occur as soon as possible. However, if we receive 
relevant adverse comment on distinct elements of the emergency vehicle 
provisions in this proposal by July 27, 2012, we will publish a timely 
withdrawal in the Federal Register indicating which provisions we are 
withdrawing. Any provisions of the DFR that are not withdrawn will 
become effective on August 7, 2012, notwithstanding adverse comment on 
any other provision. We will address all public comments in the final 
rule based on this proposed rule.
    As noted above, EPA is publishing the DFR 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 emergency vehicle proposed action 
described in Section IV below with which you agree and support as 
proposed, 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 
rule. In this way, the EPA will be able to adopt those elements of the 
DFR that are fully supported and most needed today, while considering 
and addressing any

[[Page 34152]]

adverse comments received on the proposed rule, in the course of 
developing the final rule.
    Note that Docket Number EPA-HQ-OAR-2011-1032 is being used for both 
the DFR and this Notice of Proposed Rulemaking (NPRM).

IV. 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 proposal, 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, or wildland fire apparatus. See Section IV.C and 
proposed 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 IV.C(3).
---------------------------------------------------------------------------

    \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 IV.C and IV.D.
---------------------------------------------------------------------------

    \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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B. Current Provisions for Other Emergency Vehicles and Engines

    On December 1, 2011, in a proposed rule issued jointly with the 
National Highway Traffic Safety Administration (NHTSA), EPA proposed to 
exclude light-duty emergency and police vehicles from all phases of 
greenhouse gas (GHG) emissions standards, in part due to concerns 
related to technical feasibility, and in part to harmonize with NHTSA's 
program. Consistent with authority under the Energy Policy and 
Conservation Act, NHTSA's corporate average fuel economy program 
already provides manufacturers with the option to exclude emergency 
vehicles.\8\ The agencies are considering and responding to comments on 
this proposal, and plan to finalize this rule in summer 2012.
---------------------------------------------------------------------------

    \8\ See 49 U.S.C. 32902(e).
---------------------------------------------------------------------------

    In addition to the above proposed exemption for on-highway engines 
from GHG standards, EPA has provided limited regulatory relief for 
other types of emergency-use engines. First, EPA's May 6, 2008 final 
rule adopting Tier 3 and Tier 4 standards for marine diesel engines 
allows for emergency and rescue vessels to meet an earlier, less 
stringent tier of standards under 40 CFR parts 89, 94 and 1042.\9\ We 
adopted these provisions to avoid compromising engine performance 
during emergency operation, and to ensure that more stringent emission 
standards did not cause a situation where there were no certified 
engines available for emergency vessels. Such engines are not subject 
to the Tier 4 standards, which generally involve selective catalytic 
reduction and diesel particulate filters. The regulations also allow 
for meeting less stringent standard if there are no suitable engines 
that are certified to the current standards.
---------------------------------------------------------------------------

    \9\ Final Rule: Control of Emissions of Air Pollution from 
Locomotives and Marine Compression-Ignition Engines Less Than 30 
Liters per Cylinder, 73 FR 25098, May 6, 2008, and republished to 
correct typographical errors on June 30, 2008, 73 FR 37096.
---------------------------------------------------------------------------

    EPA also adopted limited exemption provisions for emergency rescue 
equipment for small spark-ignition nonroad engines in 1999.\10\ Under 
this provision, equipment manufacturers needed to demonstrate that no 
engine models certified to current emission standards were available to 
power the emergency rescue equipment. We

[[Page 34153]]

recently moved this provision to 40 CFR part 1054 and included a 
variety of elements to clarify and improve oversight of the exemption 
in a later final rule.\11\ These elements include a requirement that 
the engines meet the most stringent standards feasible (but less than 
the current standards for certification) and annual reporting to EPA on 
the availability of compliant engines that meet the needs of other 
emergency equipment using such engines.
---------------------------------------------------------------------------

    \10\ Final Rule: Phase 2 Emission Standards for New Nonroad 
Spark-Ignition Nonhandheld Engines at or Below 19 Kilowatts, 64 FR 
15208, March 30, 1999.
    \11\ Final Rule: Control of Emissions from Nonroad Spark-
Ignition Engines and Equipment, 73 FR 59034, October 8, 2008.
---------------------------------------------------------------------------

    In these rules, EPA recognized that equipment and vessels designed 
and purpose-built exclusively for use in emergency equipment have 
demanding performance specifications and in some cases extreme duty 
cycles. The marine diesel provisions also recognize that engines 
certified to the latest emissions standards requiring emissions after-
treatment may create some interference with engine performance or 
effectiveness that may be needed in emergency circumstances, when 
installed in some emergency equipment or vessels.
    While these provisions do offer limited relief from the latest 
round of emissions standards for these engines, there is a general 
requirement to use engines meeting the most stringent emission 
standards as practical. There are also additional administrative 
responsibilities related to engine labeling, periodic reporting to EPA, 
and recordkeeping. These provisions in some cases also expire if 
compliant engines become available that can practically be used to 
provide power for the equipment in question. Furthermore, these limited 
exemption provisions are only applicable to newly certified engines. 
The regulations do not apply these provisions to in-use engines that 
are certified and deployed in emergency equipment.

C. Why is EPA taking this action?

    EPA is proposing to amend 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.\12\ 
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.\13\ 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 VII, 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.
---------------------------------------------------------------------------

    \12\ 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.
    \13\ 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.
---------------------------------------------------------------------------

    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 IV-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.\14\
---------------------------------------------------------------------------

    \14\ See Final RIA Chapter III, Note 12, above.

---------------------------------------------------------------------------

[[Page 34154]]

[GRAPHIC] [TIFF OMITTED] TP08JN12.001

    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).15 16 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.
---------------------------------------------------------------------------

    \15\ 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.
    \16\ See http://www.arb.ca.gov/diesel/tru/documents/ashguide.pdf.
---------------------------------------------------------------------------

    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 IV.C.(1)(b) 
describes the three types of routine DPF regeneration: Passive 
regeneration, automatic active regeneration, and manual (parked) active 
regeneration. A more detailed discussion is provided in a memorandum to 
the docket.\17\ Before discussing the ways that manufacturers achieve 
regeneration, though, first we discuss the reason why it is needed at 
all.
---------------------------------------------------------------------------

    \17\ See memo dated May 4, 2012, ``Diesel Particulate Filter 
Regeneration,'' Docket ID EPA-HQ-OAR-2011-1032.
---------------------------------------------------------------------------

(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

[[Page 34155]]

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

[[Page 34156]]

     On-board fuel burners upstream of the filter.\18\
---------------------------------------------------------------------------

    \18\ 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 below in Section 
VII.B. 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. 
Further discussion of this is provided below in Section VII.
(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 IV.E, below, we discuss our 
proposed regulatory action to address these issues. While our proposed 
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.

[[Page 34157]]

(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.
    It is possible to collect duty cycle data from trucks by extracting 
information that is broadcast by the engine's ECM. ECM's broadcast 
information such as engine speed, load, temperature, DPF backpressure, 
and many other parameters relevant to engine operation. In 2004 the 
Fire Apparatus Manufacturers Association conducted a data-collection 
project, downloading logged data from emergency vehicles in use across 
the United States, to document duty cycles and engine conditions 
typically experienced in the emergency fleet, including pumpers, 
aerials, and rescue vehicles in urban, suburban and rural 
communities.\19\ The 2004 FAMA data set includes 26 service months of 
data from 51 pumper trucks, 31 service months of data from 21 aerial 
trucks, and 14 service months of data from 4 rescue vehicles. Overall, 
the data reveal that emergency vehicles in urban centers log more hours 
than vehicles in suburban or rural areas, with the urban and suburban 
vehicles logging over five and four times the average rural engine 
hours, respectively, on an annual basis. This demographic data could be 
helpful to fleet managers who wish to understand why they have or have 
not experienced certain troubles with their vehicles. The data also 
indicate that vehicles with PTO capability (pumpers and aerials) 
operate in PTO mode on average about 10 percent of their operating 
time. Further, the data indicate the vast majority of emergency fleet 
operation is at loads below 10 percent of maximum capacity and engine 
speeds below 1,000 rpm. Data of this type could be helpful to engine 
manufacturers who may wish to assure that their emission control system 
designs will be successful for a given application. For the vehicles 
from which operating data were collected, FAMA determined an average 
engine load using the total horsepower, percent load, and percent time 
at load. Table IV-1 presents a summary of the engine load data compiled 
in FAMA's study.
---------------------------------------------------------------------------

    \19\ Fire Apparatus Manufacturer's Association, Fire Apparatus 
Duty Cycle White Paper, August 2004, available at http://www.deepriverct.us/firehousestudy/reports/Apparatus-Duty-Cycle.pdf.
---------------------------------------------------------------------------

    Table IV-2 presents operating data by both vehicle type and 
demographic, and Table IV-3 presents an overview of the data by vehicle 
type.

                    Table IV-1--FAMA Engine Load Data
------------------------------------------------------------------------
                                                            Population
                                     Capacity range in        average
          Apparatus type                   study              percent
                                                           running load
------------------------------------------------------------------------
Pumper...........................  315-500 hp...........              18
Aerial...........................  170-500 hp...........              30
Rescue...........................  350-500 hp...........              20
------------------------------------------------------------------------

                                 Table IV-2--FAMA Duty Cycle Data by Demographic
----------------------------------------------------------------------------------------------------------------
                                                                                                   Service area
       Service area          Operating condition      Pumper          Aerial          Rescue          average
----------------------------------------------------------------------------------------------------------------
Rural.....................  Engine Hours (Avg                301             204             301             295
                             Annual).
                            PTO Hours (Avg                    70              63  ..............  ..............
                             Annual).
                            Low Speed (% Time               11               9               7            \a\9
                             1,800 RPM).
                            Low Load (% Time                 3               6               2            \a\4
                             90%).
Suburban..................  Engine Hours (Avg               1364            1133             367            1272
                             Annual).
                            PTO Hours (Avg                   168          \b\123  ..............  ..............
                             Annual).
                            Low Speed (% Time                6               5               7            \a\6
                             1,800 RPM).
                            Low Load (% Time                 3               5               0            \a\3
                             90%).
Urban.....................  Engine Hours (Avg               1107            2379            1686            1681
                             Annual).
                            PTO Hours (Avg                    93          \b\213  ..............  ..............
                             Annual).
                            Low Speed (% Time                5               5              11            \a\7
                             1,800 RPM).
                            Low Load (% Time                 3               5               5            \a\4
                             90%).
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ Straight average by EPA from summary results. Other values in this table are weighted averages compiled by
  FAMA using individual vehicle data.
\b\ Includes both pumping and aerial operating hours.

[[Page 34158]]

                                Table IV-3--FAMA Duty Cycle Data by Vehicle Type
----------------------------------------------------------------------------------------------------------------
                                                   Pumper class    Aerial class    Rescue class
               Operating condition                    average         average         average      Fleet average
----------------------------------------------------------------------------------------------------------------
Engine Hours (Avg Annual).......................         \a\ 924        \a\ 1239         \a\ 785            1244
                                                 --------------------------------                ---------------
PTO Hours (Avg Annual)..........................              \b\ 117             ..............  ..............
                                                 --------------------------------                ---------------
Low Speed (% Time  1,800 RPM).................               7               5               9               7
Low Load (% Time  90%)........................               3               5               3               3
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ Straight average by EPA from summary results. Other values in this table are weighted averages compiled by
  FAMA using individual vehicle data.
\b\ Includes only pumping hours. Aerial operating hours averaged 69 hours per year.

    We can see from this study 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. EPA requests comment on whether any 
EPA action should be taken to explicitly address this situation beyond 
what we are already proposing in this action.
    While not addressed directly in this proposed 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 
proposing any specific action at this time related to decreasing the 
amount of time emergency vehicles operate at light load or at idle, 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

[[Page 34159]]

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 taking 
action elsewhere in this notice (See Section V) to establish this in 
our regulations. 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.\20\ 
In this proposal 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.
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    \20\ FAMA 2010, Emergency Vehicle SCR and DEF Inducement 
Guidelines; 2010 Engine Emissions Control Requirements.
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D. 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.\21\ 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.
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    \21\ 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.
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(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.\22\ 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

[[Page 34160]]

system, using a design that allows for the DPF system to reliably 
oxidize accumulated soot using continuous passive regeneration.\23\
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    \22\ See ATA/TMC, Note 21.
    \23\ 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.
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(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.

E. Proposed Regulatory Action

    As described above in Section IV.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.\24\ 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.
---------------------------------------------------------------------------

    \24\ 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.\25\
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    \25\ 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.\26\ 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.\27\ 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

[[Page 34161]]

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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    \26\ U.S. General Services Administration, Federal Specification 
for the Star-of-Life Ambulance, August 1, 2007,  http://www.deltaveh.com/f.pdf.
    \27\ 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&target%5Fpid=190109&src%5Fpid=&link%5Ftype=search&icid=.
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    EPA is also proposing an associated engine labeling requirement so 
that engines with approved emergency vehicle AECD's would be clearly 
identified and distinguished from other similar engines.
    As mentioned above in Section IV.C, 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 proposed 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 proposing amendments so that manufacturers 
could apply for (and EPA could approve) AECD's that would 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 above in Section IV.C(2)(b) 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 
IV.F(2).
    To achieve these goals, EPA understands that increased flexibility 
would 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 proposed. Upon adoption of these amendments, EPA 
would encourage requests by engine manufacturers 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 Section VII, below, 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 IV.F(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, EPA proposes that the resulting increase in 
NOX emissions not be counted against certification levels 
for applicable engine families or vehicle test groups. Furthermore, EPA 
proposes that emissions certification testing 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.\28\ EPA requests comment on whether an option 
for more frequent automatic active and/or manual active DPF 
regenerations for emergency vehicles would be beneficial for 
reliability of those DPF systems, and whether EPA should apply any 
constraints on the frequency of manual active DPF regenerations when 
approving AECD's for emergency vehicles.
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    \28\ Frequency in percent refers to the fraction of engine test 
cycles during which an automatic active regeneration occurs.
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(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

[[Page 34162]]

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 
IV.F(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, EPA proposes that the resulting increase in 
NOX emissions not be counted against certification levels 
for applicable engine families or vehicle test groups. Furthermore, EPA 
proposes that emissions certification testing be conducted with any 
approved AECD's for emergency vehicle or equipment deactivated. A 
discussion of the estimated emissions impacts of recalibration is found 
below in Section VII.B. EPA requests comments on whether an upper limit 
of average NOX emissions--considering regeneration frequency 
and duration, peak NOX emission rate, and operating 
conditions under which the AECD is triggered--should be established as 
part of the implementation of this AECD option, and what levels may be 
appropriate.
(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. EPA requests comment on whether a failsafe 
measure to provide engine exhaust backpressure relief should be 
available as an approvable AECD option, and what constraints, if any, 
should be established for this option.

F. What engines and vehicles would be affected?

    Today's proposal would apply 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 and Vehicles
    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 would be 
eligible to obtain an approved AECD of the type discussed above in 
Section IV.E. 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 
would be eligible to obtain an approved AECD of the type discussed 
above in Section IV.E.
(2) Certified Engines and Vehicles In-Use
    To address in-use engines and vehicles, EPA proposes 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 would 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 proposes to 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 would be similar to the 
information submitted for emergency vehicle or equipment AECD's.
    It is important to emphasize that this proposal would 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 would be 
permitted for emergency vehicles and emergency equipment under the 
proposed regulations, based on the extent to which the modification is 
being incorporated into new production vehicles and equipment. The 
three types are:
     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.
     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.
     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

[[Page 34163]]

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 proposal would 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 would also encourage 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.\29\ 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.
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    \29\ Although this action would 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).
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    Manufacturers of highway and nonroad engines would 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, EPA proposes that emissions certification testing be conducted 
with any approved AECD's for emergency vehicle or equipment 
deactivated. Additionally, manufacturers would not need to consider 
emergency vehicle AECD's when developing infrequent regeneration 
adjustment factors (IRAFs) or when developing deterioration factors 
(DFs). Thus, EPA proposes that manufacturers could include emergency 
and non-emergency engines and vehicles in the same engine families and 
test groups. EPA also proposes that manufacturers may apply for 
emergency vehicle AECD's for new, existing, and/or formerly approved 
emissions certificates. EPA requests comments on this aspect of the 
proposal.

V. Scheduled Maintenance and Maintenance Interval for Replacement of 
Diesel Exhaust Fluid

    EPA is proposing to include new provisions in its regulations that 
explicitly permit replacement of diesel exhaust fluid (DEF) as part of 
approved emission-related scheduled maintenance and set out the 
permitted maintenance intervals for replacement of DEF on diesel fueled 
new motor vehicles, new motor vehicle engines and new nonroad 
compression-ignition (NRCI) engines.

A. Background

    EPA's regulations define the emission-related scheduled maintenance 
that may be performed for purposes of durability testing and for 
inclusion in maintenance instructions provided to purchasers of new 
motor vehicles and new motor vehicle engines.

[[Page 34164]]

See 40 CFR 86.094-25(b); 40 CFR 86.004-25(b); 40 CFR 86.1834-01(b). The 
regulations include lists of emission-related maintenance and intervals 
for this maintenance. See 40 CFR 86.004-25(b)(4); 40 CFR 86.1834-
01(b)(4). For example, in general, the maintenance interval for the 
adjustment, cleaning, repair of the following items is 100,000 miles of 
use, and then at 100,000 mile intervals thereafter for diesel cycle 
light-duty vehicles, diesel cycle light-duty trucks, and light heavy-
duty diesel engines and at 150,000 mile intervals for medium and heavy 
heavy-duty diesel engines: Fuel injectors, turbochargers, electronic 
engine control units, particulate trap or trap-oxidizers, exhaust gas 
recirculation systems, and catalytic converters. The regulations also 
include a procedure that allows manufacturers to request a different 
maintenance schedule or to request new scheduled maintenance, which 
includes maintenance that is a direct result of the implementation of 
new technology not found in production prior to the 1980 model year. 
See 40 CFR 86.094-25(b)(7); 40 CFR 86.1834-01(b)(7).
    Similarly, EPA's regulations applicable to nonroad compression-
ignition (NRCI) engines define the emission-related maintenance that 
may be performed for purposes of providing ultimate purchasers written 
instructions for properly maintaining and using the engine. Such 
emission-related maintenance and associated intervals apply to service 
accumulation on emission-data engines. See 40 CFR 1039.125. This 
regulation includes lists of emission-related maintenance and intervals 
for this maintenance. See 40 CFR 1039.125(a)(2) and 1039.125(a)(3). For 
example, in general, the maintenance interval for adjustment, cleaning, 
repair or replacement for catalytic converters on engines below 130 
kilowatt (kW) may not occur more frequently than after 3,000 hours and 
4,500 hours for engines at or above 130 kW. This regulation also 
includes a procedure that allows manufacturers to request a different 
maintenance schedule or to request new scheduled maintenance, which 
includes maintenance on emission-related components that were not in 
widespread use on NRCI engines prior to 2011.
    EPA adopted new emission standards applicable to emissions of 
NOX from light-duty vehicles and trucks on February 10, 2000 
(65 FR 6698). Similarly EPA adopted new standards applicable to 
emissions of NOX from heavy-duty highway engines and 
vehicles on January 18, 2001 (66 FR 5002). These standards have been 
phased in since model year 2004 and all were fully phased-in by 2010. 
Most manufacturers of affected diesel engines and vehicles have chosen 
to use a NOX reduction technology known as selective 
catalytic reduction (SCR) in order to meet these requirements. SCR 
systems use a nitrogen-containing reducing agent that usually contains 
urea and is known as diesel exhaust fluid (DEF). The DEF is injected 
into the exhaust gas and requires periodic replenishment by refilling 
the DEF tank.
    In addition, EPA adopted new emission standards applicable to 
emissions of NOX from NRCI engines on June 29, 2004 (69 FR 
38958). These standards have begun to be implemented pursuant to a 
phase-in that began in the 2011 model year. EPA conducted a webinar 
workshop on July 26, 2011 with NRCI engine manufacturers to address the 
application of SCR emission technology. Some manufacturers are 
currently certifying their NRCI engines with the use of SCR systems and 
we expect that many manufacturers will use SCR systems to meet the 
final Tier IV NOX reduction requirements for their diesel 
engines.
    In a Guidance Document signed on March 27, 2007 (CISD-07-07), EPA 
indicated its belief that the requirements for critical emission-
related maintenance would apply to replenishment of the DEF tank and 
that manufacturers wanting to use SCR technology would likely have to 
request a change to scheduled maintenance per 40 CFR 86.1834-01(b)(7) 
or 86.094-25(b)(7).
    Following the completion of the Guidance, EPA received several 
requests for new maintenance intervals for SCR-equipped motor vehicles 
and motor vehicle engines.\30\ EPA granted these requests for model 
years 2009 through 2010 for light-duty vehicles and 2009 through 2011 
for heavy-duty engines, in a notice that was published in the Federal 
Register (74 FR 57671, November 9, 2009). In granting the requests, EPA 
stated that it
---------------------------------------------------------------------------

    \30\ See letter dated March 31, 2009 from Giedrius Ambrozaitis, 
Alliance of Automobile Manufacturers, Director, Environmental 
Affairs to Karl Simon, EPA, Director, Compliance and Innovative 
Strategies Division; Letter dated May 8, 2009 from Jed Mandel, 
Engine Manufacturers Ass'n to Karl Simon, EPA, Director, Compliance 
and Innovative Strategies Division; Letters dated June 29, 2009 and 
October 8, 2009 from Steven C. Berry, Director Government Relations 
Volvo Powertrain.

believes the maintenance of performing DEF refills on SCR systems 
should be considered as `critical emission-related scheduled 
maintenance.' EPA believes the existing allowable schedule 
maintenance mileage intervals applicable to catalytic converters are 
generally applicable to SCR systems which contain a catalyst, but 
that the DEF refills are a new type of maintenance uniquely 
associated with SCR systems. Therefore, the 100,000-mile interval at 
40 CFR Sec.  86.1834-01(b)(4)(ii) for catalytic converters on 
diesel-cycle light-duty vehicles and light-duty trucks (and any 
other chassis-certified vehicles) and the 100,000-mile interval (and 
100,000 mile intervals thereafter) for light heavy-duty diesel 
engines and the 100,000-mile interval (and 150,000 mile intervals 
thereafter) for medium and heavy heavy-duty diesel engines at 40 CFR 
Sec.  86.004-25(b)(4)(iii) are generally applicable to SCR systems. 
As noted, the SCR systems are a new type of technology designed to 
meet the newest emission standards and the DEF refill intervals 
represent a new type of scheduled maintenance; therefore, EPA 
believes that manufacturers may request from EPA the ability to 
---------------------------------------------------------------------------
perform the new scheduled maintenance of DEF refills.

    EPA approved a maintenance interval for refill of DEF tanks equal 
to the applicable vehicle's scheduled oil change interval for light-
duty vehicles and light-duty trucks. For heavy-duty engines, EPA 
approved a maintenance interval equal to the range (in miles or hours) 
of the vehicle operation that is no less than the vehicle's fuel 
capacity (i.e., a 1:1 ratio), for vocational vehicles such as dump 
trucks, concrete mixers, refuse trucks and similar typically centrally 
fueled applications. For all other vehicles equipped with a constantly 
viewable DEF level indicator (e.g. a gauge or other mechanism on the 
dashboard that will notify the driver of the DEF fill level and the 
ability to warn the driver of the need to refill the DEF tank before 
other inducements occur), EPA approved a DEF tank refill interval equal 
to no less than twice the range of vehicle's fuel capacity (i.e., a 2:1 
ratio). For all other vehicles that do not have a constantly viewable 
DEF level indicator, EPA approved a DEF tank refill interval equal to 
no less than three times the range of the vehicle's fuel capacity 
(i.e., a 3:1 ratio).
    Engine and vehicle manufacturers provided additional requests for 
new maintenance intervals for vehicles and engines in model years not 
covered by the November 9, 2009 Federal Register notice.\31\ On January 
5, 2012 (77 FR 488), EPA approved new maintenance

[[Page 34165]]

intervals for the refill of DEF tanks applicable to light-duty vehicles 
and light-duty trucks, as well as for heavy-duty engines for 2011 and 
later model years. For light-duty vehicles and light-duty trucks the 
approved interval for DEF refill remains at the scheduled oil change 
interval. For heavy-duty engines the approved maintenance interval for 
vocational vehicles remains at 1:1 and for all other types of heavy-
duty vehicles the approved maintenance interval is 2:1.
---------------------------------------------------------------------------

    \31\ See letter dated July 20, 2010 from Giedrius Ambrozaitis, 
Alliance of Automobile Manufacturers, Director, Environmental 
Affairs to Karl Simon, EPA, Director, Compliance and Innovative 
Strategies Division; Letter dated June 13, 2011 from Timothy A. 
French, Engine Manufacturers Ass'n to Justin G. Greuel, EPA, 
Compliance and Innovative Strategies Division; Letter dated April 
28, 2011 from Steve Berry, Volvo Powertrain; Letters dated August 
18, 2011 and September 27, 2011 to Karl Simon, EPA, Director, 
Compliance and Innovative Strategies Division from R. Latane 
Montague, Hogan Lovells.
---------------------------------------------------------------------------

    On July 26, 2011, EPA conducted a webinar workshop for NRCI engine 
manufacturers in order to provide EPA's thinking, at the time, about 
the certification of SCR-equipped NRCI engines. EPA discussed the issue 
of maintenance intervals for the refill of DEF and instructed 
manufacturers to follow the regulatory provisions in order to petition 
EPA for what it thought were appropriate intervals. Following the 
workshop, EPA received several requests for new maintenance intervals 
for SCR-equipped NRCI engines. EPA granted these requests for 2011 and 
later model years in a notice that was published in the Federal 
Register (77 FR 497, January 5, 2012). In granting the requests, EPA 
stated that it

believes that SCR systems are a new technology and are properly 
considered a critical emission-related component. EPA believes the 
existing allowable schedule maintenance mileage intervals applicable 
to catalytic converters are generally applicable to SCR systems 
which contain a catalyst, but that the SCR systems are a new type of 
technology and that DEF refills are a new type of maintenance 
uniquely associated with SCR systems. Therefore, the 3,000 hour 
(engines below 130 kW) and 4,500 hour (engines at or above 130kW) 
intervals are generally applicable to SCR systems. As noted, the SCR 
systems are a new type of technology designed to meet the newest 
emission standards and the DEF refill intervals represent a new type 
of scheduled maintenance; therefore, EPA believes that manufacturers 
may request from EPA the ability to perform the new scheduled 
maintenance of DEF refills.

    EPA approved a maintenance interval for refill of DEF tanks that 
shall be no less than the equipment's fuel capacity (i.e., a 1:1 ratio 
of DEF refill to fuel refill).

B. Proposed Regulatory Action

    EPA is today proposing to add DEF replenishment to the list of 
scheduled emission-related maintenance for diesel-fueled motor vehicles 
and motor vehicle engines, as well as for NRCI engines that use SCR. 
EPA is also proposing to incorporate appropriate maintenance intervals 
for this scheduled maintenance.
(1) Scheduled Emission-Related Maintenance
    EPA is proposing to list DEF replenishment as scheduled emission-
related maintenance in 40 CFR 86.004-25(b)(4) and 40 CFR 86.1834-
01(b)(4) for diesel-fueled motor vehicles and motor vehicle engines, as 
well as 40 CFR 1039.125(a)(2) and 40 CFR 1039.125(a)(3) for NRCI 
engines that use SCR.
    Over the past several model years, since the implementation of the 
most recent standards for NOX, many manufacturers have 
chosen SCR as the technology used to meet these stringent 
NOX standards. Typically, should a manufacturer desire new 
maintenance (that it wishes to recommend to purchasers and perform 
during service accumulation on emission-data engines) not found in 40 
CFR 86.004-25(b)(4) and 86.1834-01(b)(4) or at 40 CFR 1039.125(a)(2) 
and 40 CFR 1039.125(a)(3), then it utilizes the provisions allowing 
manufacturers to request such maintenance. Given that SCR use is now 
common in the industry and replenishment of DEF is necessary for SCR to 
be effective, it is appropriate to add DEF replenishment to the list of 
scheduled emission-related maintenance published in the Code of Federal 
Regulations (CFR), rather than rely on the provisions of paragraph 
(b)(7) for motor vehicles and paragraph 1039.125(a)(5) for NRCI 
engines.
(2) Maintenance Intervals for On-Highway Diesel Engines
    EPA is also proposing to incorporate appropriate maintenance 
intervals for this scheduled maintenance. In general, they are the same 
as were approved under the (b)(7) process. For light-duty vehicles and 
light-duty trucks, we are proposing an interval equal to the scheduled 
oil change interval for the vehicle. Light-duty vehicles and trucks do 
not have the carrying and storage capacity required for the quantity of 
DEF needed to satisfy longer maintenance intervals such as the 100,000 
mile scheduled maintenance interval generally applicable to catalytic 
converters. As EPA explained in its previous notices regarding this 
issue, automobile manufacturers have stated that it takes approximately 
an 8 gallon DEF tank to assure the DEF will last for the length of a 
typical scheduled oil change interval. Assuming an oil change interval 
of 10,000 miles, a DEF tank size of approximately 80 gallons would be 
required to meet a 100,000 mile DEF refill maintenance interval. Even a 
16-20 gallon DEF tank (to meet a 2 oil change interval) would interfere 
with the space that is necessary for typical light-duty vehicle design 
and transportation needs of the consumer. Interior cabin volume and 
cargo space are highly valued attributes in light-duty vehicles and 
trucks. Manufacturers have historically strived to optimize these 
attributes, even to the point of switching a vehicle from rear-wheel 
drive to front-wheel drive to gain the extra interior cabin space taken 
up by where the drive shaft tunnel existed, or switching the size of 
the spare tire from a conventional sized tire to a small temporary tire 
to gain additional trunk space. Thus any significant interior, cargo or 
trunk space used to store a DEF tank would be unacceptable to 
customers. There are also packaging concerns with placing a large DEF 
tank in the engine compartment or in the vehicle's undercarriage. Most 
vehicle undercarriages are already crowded with the engine, exhaust 
system, including catalytic converters and mufflers, fuel tank, etc. 
limiting any available space for a DEF tank.
     In addition to the inherently space constrained areas on the 
vehicle to place both fuel tanks and DEF tanks (an additional 8 gallon 
tank represents a very significant demand for space) the addition of 
the weight associated with the DEF represents significant concerns 
(e.g. performance and efficiency) on the operation of the vehicle. For 
example, assuming a density of 9 lb/gallon, an 8 gallon DEF tank 
represents an additional 72 lbs on a vehicle already looking to 
optimize performance. Adding additional DEF tank size to even 
accommodate a two-oil change interval is not feasible or practical 
given these weight constraints. A requirement for a larger DEF tank may 
also have an adverse effect on the ability of a manufacturer to meet 
greenhouse gas emission standards and fuel economy standards.
    EPA notes that a DEF refill maintenance interval that is equivalent 
and occurring with the oil change interval is a fairly long interval 
(e.g. 7,500 to 12,500 miles) for light-duty vehicles and trucks and is 
not likely to result in overly frequent maintenance under typical 
vehicle driving. EPA also believes that an adequate DEF supply will be 
available to perform the DEF refills at the stated intervals. EPA 
believes it important to also consider when, where and how often 
vehicle owners or operators are most likely to perform the DEF refill 
maintenance. For light-duty vehicles and light-duty trucks, EPA 
believes the requested DEF refill interval's association with the oil 
change interval is appropriate given the likelihood of DEF availability 
at service

[[Page 34166]]

stations and the likelihood that DEF refill would occur during such 
service.
    EPA also notes that heavy-duty engines that are certified as part 
of complete trucks have been treated in the same manner as light-duty 
trucks and thus have been subject to the DEF refill interval associated 
with the oil change. We are proposing to continue this treatment in the 
regulations. In addition, EPA is aware that several manufacturers are 
exploring whether the DEF refill interval should not be linked to the 
oil change interval since the historical oil change interval (e.g., 
7,000-8,500 miles) is potentially increasing to higher mile intervals 
(e.g., 15,000 to 30,000 miles, even higher for synthetic oil). We 
invite comment on the necessity and appropriateness of ``de-linking'' 
the DEF refill interval from the oil change interval, as well as 
comments on proper methods to increase the likelihood that DEF refill 
maintenance would occur in the appropriate interval (e.g., linking to 
vehicle fuel capacity, inducement criteria, etc.), should it not be 
linked to the oil change interval.
    For heavy-duty engines, we are proposing that for vocational 
vehicles such as dump trucks, concrete mixers, refuse trucks and 
similar typically centrally fueled applications, the DEF tank refill 
interval should equal the range (in miles or hours) of the vehicle 
operation that is no less than the vehicle's fuel capacity (i.e., a 1:1 
ratio). For all other vehicles, the DEF tank refill interval must 
provide a range of vehicle operation that is no less than twice the 
range of vehicle's fuel capacity (i.e., a 2:1 ratio). EPA believes it 
is reasonable to base the DEF refilling event on diesel refueling 
intervals given that it is likely that the DEF refill maintenance would 
be undertaken at the time of fuel refill due to DEF infrastructure 
developed at diesel refueling stations. EPA believes that these DEF 
refilling intervals are technologically necessary. EPA knows of no SCR 
technology for any heavy-duty engine application that is capable of 
operating without a DEF refill for the high mileage levels associated 
with other maintenance intervals. As an example, assuming that 25,000 
gallons of diesel fuel were consumed to reach a 150,000-mile interval, 
the amount of DEF required (assuming a 3% DEF consumption rate) would 
require 750 gallons of DEF weighing approximately 6,750 lbs. A line-
haul truck is allowed a maximum gross vehicle weight of 85,000 lbs. of 
which approximately 45,000 pounds is for cargo carrying. A DEF tank of 
750 gallons would reduce the cargo-carrying capacity by 15%. Another 
example from the line haul industry suggests that a DEF tank size of 
over 900 gallons would be needed to reach the 150,000-mile interval for 
a common highway vehicle with a diesel fuel capacity of 200 gallons and 
achieving 6.5 miles per gallon fuel economy. Similarly, a medium heavy-
duty engine (``chassis cabs'') example would require 375 gallons of DEF 
weighing 3,275 lbs to meet a 150,000-mile interval. EPA believes that 
such tank sizes are clearly not technologically feasible in light of 
the weight and space demands and constraints on heavy-duty trucks and 
the consumer demand to maximize cargo carrying capacity.
    The Agency also believes that intervals shorter than 150,000 miles 
but longer than those we are proposing would require DEF tanks that are 
too large or too heavy to be feasibly incorporated into vehicles. 
Available data show that heavy-duty engines equipped with SCR-based 
systems will consume DEF at a rate that is approximately 2%-4% of the 
rate of diesel fuel consumption. Because of inherent space and weight 
constraints in the configuration and efficient operation of heavy-duty 
vehicles, there are size limits on the DEF tanks. Currently, there are 
truck weight limits that manufacturers must address when making or 
modifying truck designs. EPA expects and believes that manufacturers 
are taking significant and appropriate steps in order to install 
reasonably sized DEF tanks to achieve the DEF refills intervals noted. 
For example, manufacturers are taking such steps as reducing the number 
of battery packs on vehicles despite customer demands or designing 
space saving configurations, in some instances extending an already 
very limited frame rail distance to incorporate the DEF tanks and SCR 
systems, moving compressed air tanks inside the frame rails, 
redesigning fuel tank configurations at significant costs, and 
otherwise working with significant size and weight constraints to 
incorporate DEF tanks. There are several factors that support the good 
engineering judgment that underlies the recommended DEF refill 
intervals. The great majority of heavy-duty engines produced with SCR 
DEF tanks will provide a range of vehicle operation that is no less 
than twice the range of the vehicle's fuel capacity; thus, the DEF tank 
size will provide at least double the vehicle's operating range as 
provided by the fuel tank. Vehicle operators will generally refill DEF 
at the same time and location that they refill the tanks thus these 
vehicles will already be carrying twice as much DEF as the SCR system 
could ever consume between refills. Also, manufacturers have been 
incorporating warning signals and performance-related inducements on 
their SCR-equipped vehicles to ensure the substantial likelihood that 
DEF refilling will occur,\32\ and there is considerable evidence that 
heavy-duty vehicle operators in the United States have in practice been 
refilling their DEF tanks prior to the tanks becoming empty in 
virtually all situations.\33\
---------------------------------------------------------------------------

    \32\ As discussed in Section IV above, we are proposing options 
for manufacturers of emergency vehicles and engines to avoid the 
harsh consequences of certain performance inducements. Since 2010, 
some manufacturers have been implementing guidance on alternative 
inducement criteria for emergency vehicles.
    \33\ See 76 FR 32886 (June 7, 2011) and the studies cited at 
32889-32891.
---------------------------------------------------------------------------

    EPA was provided with examples of the consequences of requiring 
heavy-duty vehicles to accommodate a DEF refill interval of 5:1, and 
the information provided to the Agency strongly suggested that great 
compromises would be required in cost, weight and utility. Increased 
tank sizes and weights on the magnitude of 150 to 325 lbs. would be 
required and in some cases diesel fuel volumes would need to be 
reduced. The extra weight associated with the DEF required to meet the 
2:1 refill intervals represents a significant challenge to 
manufacturers seeking to meet both weight and size requirements for 
their vehicle designs. In addition, requiring a longer DEF refill 
interval may result in increased greenhouse gases and decreased fuel 
economy. EPA believes that in light of the existing tight space 
constraints and the overall desire to maximize cargo-carrying capacity 
to minimize emissions and meet consumer operational demands, and the 
built-in DEF tank size buffer to insure DEF refills, that the proposed 
tank DEF tank sizes are technologically necessary and are also 
reasonable and appropriate. EPA believes that requiring tank sizes 
above these ratios will cause increases in space constraints and weight 
that would not be appropriate for these vehicles. Similarly, 
manufacturers note that only a small number of applications will employ 
the 1:1 refilling ratio and that such vehicle applications have very 
limited vehicle space available to house surplus DEF. Such applications 
(e.g., a garbage truck, concrete mixer, beverage truck, or airport 
refueler) will also be refueled daily at central locations. At 
approximately 0.134 ft\3\ per gallon, any extra DEF would displace 
significant space available to vehicle components and subsystems on 
both the vocational trucks at the 1:1 refill interval as well as the 
2:1 vehicles.

[[Page 34167]]

    During the previous administrative process leading to the January 
5, 2012 Federal Register notice approving new maintenance intervals, 
EPA received a comment from one manufacturer (Navistar) suggesting that 
a longer DEF refill interval in the range of 35,000 to 45,000 miles was 
appropriate. EPA responded to these comments in detail in that 
notice.\34\ As discussed in that notice, Navistar claimed that other 
technology is available that would need a maintenance interval no 
shorter than this. However, EPA found no evidence that such technology 
is actually available at this time. More importantly, the fact that 
other technology may be able to have a longer maintenance interval does 
not mean that a longer maintenance interval is appropriate for DEF-
based SCR. Navistar suggested that maintenance intervals can be 
increased by doubling DEF tank size. EPA does not believe that 
requiring such an increase is appropriate given the numerous negative 
consequences discussed above. EPA also explained that Navistar's 
suggestion of reducing engine-out emissions of NOX would 
likely lead to an increase in fuel consumption, and possible increases 
in GHG emissions, and could either require increases in the size of the 
fuel tank or more reductions in the operating range of a vehicle before 
needing to refill, which would compromise a critical design parameter 
of heavy-duty vehicles. EPA does not believe the desire to increase DEF 
maintenance intervals justifies such consequences. After reviewing 
these data, EPA believes that longer refill intervals than those 
proposed above would require larger and heavier DEF tanks. The design 
and engineering work performed by manufacturers thus far indicates that 
the recommended DEF refill intervals noted above approximate the 
maximum feasible maintenance intervals associated with reasonable DEF 
tank sizes. In any case these refill intervals are appropriate and 
reasonable given the substantial negative consequences of longer DEF 
refill interval requirements. The recommended maintenance intervals 
ensure that the function and operational efficiency of such vehicles 
are not overly compromised. Based on this information we believe the 
proposed intervals are warranted.
---------------------------------------------------------------------------

    \34\ See 77 FR 488, at 495-96 (January 5, 2012).
---------------------------------------------------------------------------

    EPA has received comments from certain manufacturers indicating 
that EPA should set the minimum required DEF refill interval at an 
interval equal to the vehicle's fuel capacity (i.e., a 1:1 ratio) for 
all heavy-duty engines.\35\ The commenters claim that this shorter 
maintenance interval is ``necessary and appropriate to reflect current 
and anticipated changes in vehicle designs, significant changes in 
inducement strategies, and the increased availability of DEF.'' The 
commenters note that certification practices of the EPA regarding 
inducement practices for SCR-equipped engines make it ``essentially 
impossible for an SCR vehicle to operate without regular DEF 
replenishment.'' They state that the severity of inducements related to 
DEF levels (e.g. severe reduction in engine power and/or vehicle speed) 
is ``extraordinary and must be taken into account'' when EPA is 
determining appropriate maintenance intervals. They state that ``in 
light of these severe inducements, it is reasonable to expect that a 
driver with a 1:1 tank ratio will operate under a firm discipline that 
the DEF tank must be refilled every time the fuel tanks are filled, as 
opposed to a driver with a 2:1 or greater tank ratio who may become 
accustomed to filling the DEF tank only when necessary, and is 
therefore more likely to rely on gauge levels, warnings, and 
inducements to trigger refills.''
---------------------------------------------------------------------------

    \35\ See letters dated August 18, 2011 and September 27, 2011 to 
Karl Simon, EPA, Director, Compliance and Innovative Strategies 
Division from R. Latane Montague and Hogan Lovells.
---------------------------------------------------------------------------

    The commenters also state that EPA's promulgation of new standards 
regulating greenhouse gases increase the size and weight restraints 
associated with DEF tank size.
    EPA has adopted new greenhouse gas standards for heavy-duty on-
highway trucks, and manufacturers have moved to voluntarily increase 
the fuel efficiency of their vehicles in advance of the effective dates 
of those regulations. Within these regulations, EPA recognizes the 
impact of weight savings on fuel efficiency and GHG emissions. In 
addition, manufacturers have developed innovative new DEF dosing 
strategies to reduce CO2 emissions. These new strategies may 
involve increasing the DEF dosing rate. Increasing the DEF dosing rate 
also makes it more difficult to satisfy a 2:1 tank size ratio without 
increasing the size of the DEF tank above the size EPA previously 
considered the maximum reasonable size. For this reason, if the 
application of the 1:1 tank ratio is not expanded, EPA will effectively 
be mandating larger DEF tanks, with their accompanying weight increase, 
in order to accommodate technology advancements developed to reduce 
CO2 emissions--tanks that are larger than the tanks EPA 
determined to be the maximum reasonably required in 2009. In addition, 
this could inadvertently cause manufacturers to restrict application of 
the most fuel efficient engines to vehicles that have reduced range 
between fuel and DEF refills, such that they will be unattractive to 
the line-haul fleets that consume the most fuel.
    The commenters elaborated that:

    To meet the next round of GHG reduction requirements, some 
manufacturers expect to increase DEF dosing by as much as 100% over 
current levels. These increased levels of dosing will require a 
corresponding increase in DEF tank capacity and size to meet the 
existing 2:1 tank ratio requirements. For example, increasing DEF 
dosing by 40% on average would require an increase in DEF tank size 
of approximately 40% (depending on how much extra capacity was 
included in the tanks used in previous model years). The shape, size 
and location of DEF tanks on a truck frame are constrained by a 
number of factors including: the need to place the tank below the 
filler-neck; the need for clearance from other components such as 
fuel tanks, battery boxes, air tanks, diesel particulate filters, 
and the drive axle and wheels; the need for gravity feed; body 
installation requirements; clear-back-of-cab requirements; weight 
distribution requirements; bridge formula and related axle placement 
issues; and fuel capacity/driving range demands.

    The commenters state that another consequence of the greenhouse gas 
regulations is more attention to improved aerodynamics and weight 
reduction, which are harmed by the need for a 2:1 DEF tank size 
requirement. They claim that EPA should allow manufacturers to use all 
available options to increase fuel efficiency and meet greenhouse gas 
standards. They claim that the possible harm of allowing shorter 
maintenance intervals are minimal, given the severe negative 
inducements associated with failure to replenish the DEF tank.
    EPA is not proposing to allow a 1:1 DEF maintenance interval across 
the heavy-duty engine class at this time. EPA notes that manufacturers 
have been meeting a 2:1 ratio for DEF tank size for the past two years 
and the commenters have not provided sufficient evidence that this 
ratio will be infeasible in the future. Moreover, the commenters have 
not shown that any change in the maintenance interval is necessary or 
appropriate throughout the heavy-duty engine category, rather than for 
particular applications, or that a refill interval as low as 1:1, 
rather than 1.8:1 or 1.5:1, is necessary or appropriate. The 
feasibility of the greenhouse gas standards was not predicated on 
substantial increases in DEF dosing rate, although that was a possible 
method of compliance, and the commenters have not shown that the 
increase in tank size

[[Page 34168]]

that would be associated with increased dosing, which need not be 
large, would be inconsistent with space constraints. While EPA agrees 
that the warnings and inducements in place for failure to replenish DEF 
will restrict the ability of operators to run without DEF, and have 
made operation without DEF virtually unheard of, a DEF tank ratio of 
1:1 greatly increases the likelihood that operators will need to make 
more frequent stops to replenish DEF, and possibly may need to stop 
solely to replenish DEF, which may place a greater burden on the 
operator in terms of the frequency of DEF refills. However, we request 
comment on this proposal and we do not rule out the possibility we may 
in the final rule allow a shorter maintenance interval at least in some 
situations beyond what we have proposed. In particular, we request 
comment on whether such an interval may be appropriate in the future or 
whether an approach that is limited to a portion of the heavy-duty 
engine category or that uses an interval between 2:1 and 1:1 may be 
appropriate.
    EPA also notes that the regulations allow any manufacturer to 
petition EPA under the ``paragraph (b)(7) process'' for a shorter 
maintenance interval than that promulgated for DEF refills if the 
manufacturer can show that a shorter interval is technologically 
necessary for the particular engine or vehicle configuration being 
certified.
(3) Maintenance Intervals for Nonroad Compression-Ignition Engines
    EPA is also proposing to incorporate appropriate maintenance 
intervals for the scheduled maintenance of DEF refills on SCR-equipped 
NRCI engines. We are proposing the same interval (i.e., 1:1 ratio) as 
was approved under the Sec.  1039.125(a)(5) process.
    EPA believes it appropriate to evaluate the DEF refill rates by 
taking into consideration the space and weight constraints typically 
involved with the range of nonroad compression-ignition engines using 
SCR systems, including safety and impacts of weight and dosing rates on 
greenhouse gas emissions and fuel economy. EPA also believes it 
appropriate to take into consideration the likelihood that the 
maintenance of DEF refills will be performed by the owner or 
operator.\36\
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    \36\ See 40 CFR 1039.125(a)(5).
---------------------------------------------------------------------------

    EPA knows of no SCR technology for NRCI engines that is yet capable 
of attaining longer operation (generally beyond one tank full of 
diesel) without a DEF refill. As noted by the requests received for a 
shorter interval, there are significant space and weight constraints 
associated with increasing the DEF tank size in order to accommodate a 
2:1 refill ratio. EPA believes it appropriate to take into 
consideration the need for locating the DEF tank in close proximity to 
the fuel tank and the remainder of the SCR system, as well as the 
increased likelihood that the DEF tank will be refilled if it becomes 
standard operating practice to refill it at the same time as the fuel 
tank. EPA believes that such nonroad equipment is similar to centrally-
fueled heavy-duty on-highway vehicles and that there is a sufficient 
basis and a reasonable expectation that DEF tank refills will occur on 
a timely basis. In addition, because this maintenance is considered 
critical emission-related maintenance, Sec.  1039.125 requires that 
manufacturers ensure that it have a reasonable likelihood of being done 
at the recommended intervals on in-use engines. Paragraph 
1039.125(a)(1) sets forth several methods by which such demonstration 
can be made, including data showing that if a lack of maintenance 
increases emissions, it also unacceptably degrades the engine's 
performance. Thus, manufacturers will need to show compliance with this 
requirement to be certified. In the context of SCR systems and the 
potential of an empty DEF tank and an inoperable SCR system, EPA notes 
that equipment under such operating conditions are expected to shut 
down or idle only.\37\
---------------------------------------------------------------------------

    \37\ See 76 FR 32886 (June 7, 2011) and related inducement 
criteria, see also Note 32 above regarding inducements for emergency 
vehicles and engines.
---------------------------------------------------------------------------

VI. Nonroad Engines in Temporary Emergency Service

    As noted previously, EPA is proposing to adopt special provisions 
for engines used in dedicated emergency vehicles to ensure that 
manufacturers are able to design and implement reliable, robust 
emission control systems with regeneration strategies that do not 
interfere with the mission of emergency vehicles. However, we are not 
proposing to extend this option for other engines that are not intended 
for emergency vehicles. Nevertheless, based on information provided to 
us from engine manufacturers, we have some concern that nonroad engines 
not normally used for emergencies may be needed in unusual emergency 
situations that may require very limited and temporary relief so that 
emission controls do not hinder the engine's performance in such 
emergency conditions. This section describes a flexibility that we are 
proposing to address this.
    Our existing nonroad engine compliance regulations in 40 CFR 
1068.101(b)(1)(ii) allow operators to temporarily disable or remove 
emission controls to address emergency situations. However, they do not 
necessarily allow manufacturers to design the emission controls to be 
disabled or removed. This has become a potential problem for modern 
electronically controlled engines, where many emission controls are 
integrated into the engine's control software. There is currently no 
way for an operator to selectively disable emission control software, 
while maintaining engine function. The proposed regulatory text would 
effectively extend the policy expressed in 40 CFR 1068.101(b)(1)(ii) to 
emission control software.

A. Use of Nonroad Engines in Emergency Situations

    The provisions we are proposing are intended primarily to address 
engines used for power generation or in construction equipment. 
However, it is important to note that we are not proposing to limit 
this flexibility to such engines. For example, portable diesel-powered 
generators are often used to provide electrical power after natural 
disasters. If the generator is providing power to a medical facility, 
then any interruption in service could risk the lives of the patients. 
This is just one example of how an ordinary piece of nonroad equipment 
could be used in an emergency situation. Others would include 
bulldozers repairing a levee or a crane removing debris.
    The Tier 4 standards have resulted in much of this equipment being 
equipped with SCR catalysts that require a reductant. The reductant is 
typically supplied as a urea water solution known as diesel exhaust 
fluid (DEF). The engines in this equipment generally include controls 
that limit the function of the engines if they are operated without 
urea. Such controls are generally call ``inducements'', because they 
induce the operator to supply urea to the equipment. While we are 
confident that DEF is now widely and easily available in the United 
States, we are concerned that in emergency circumstances there may be a 
possibility of a temporary supply shortage. We believe that in such 
situations, temporary flexibilities may be appropriate because the 
possibility of risk to human life sufficiently outweighs the temporary 
emissions increases that may occur if SCR-equipped engines are used 
without DEF. As indicated below, this flexibility is very narrow and

[[Page 34169]]

contains several provisions to ensure the need for the relief. We do 
not believe it can or will be used in situations where there is no 
critical need for such relief.

B. Proposed Regulatory Action

(1) General Requirements
    We are proposing a new section 1039.665 that would specify 
provisions that allow for AECDs that are necessary to ensure proper 
function of engines and equipment in emergency situations. AECDs 
approved under this section would not be defeat devices. The section 
would include the following provisions:
     Manufacturers would be allowed to ask for approval at any 
time. Still, we would encourage manufacturers to obtain preliminary 
approval before submitting an application for certification. And in 
unusual circumstances, we could allow manufacturers to apply an 
approved emergency AECD to engines and equipment that have already been 
placed into service as a ``field fix''.
     The manufacturer would be required to keep records to 
document requests for and use of emergency AECDs under this section and 
submit a report to EPA within 60 days of the end of each calendar year 
in which it authorizes use of the AECD
     We would approve an AECD only where we determine certain 
criteria are met, as described below.
    We are proposing to address such AECDs as part of certification and 
would only authorize the certifying manufacturer to activate them.
(2) Approval Criteria
    Approval of AECDs under the proposed regulations would be based on 
certain general and specific criteria. A general criterion is that the 
AECD would need to be consistent with good engineering judgment. When 
used in our regulations, the phrase ``good engineering judgment'' has a 
specific meaning as described in 40 CFR 1068.5. By specifying that the 
AECD be consistent with good engineering judgment, we address 
unforeseen technical details that may arise.
    We are also proposing three specific criteria that must be met. 
Each of these criteria is intended to ensure that any adverse 
environmental impacts are minimized. These criteria are:
     The AECD must be designed so that it cannot be activated 
without the specific permission of the certificate holder. We would 
specify that the AECD must require the input of a temporary code or 
equivalent security feature.
     The AECD must become inactive within 24 engine hours of 
becoming active (or other period we approve in unusual circumstances).
     The manufacturer must show that the AECD deactivate 
emission controls (such as inducement strategies) only to the extent 
necessary to address the expected emergency situation.
(3) Allowable Use of Emergency AECDs
    This allowance is intended generally to address SCR-equipped 
engines operating in emergency situations when DEF is unavailable. In 
such cases, inducement strategies could result in a loss of power of 
the engine which could effectively prevent the equipment from 
functioning. Under this provision, a manufacturer could include a 
dormant feature in the engine's control software that could be 
activated to disable inducement strategies.
    We are also proposing to allow this for other types of controls, 
where a manufacturer can clearly demonstrate that this relief could be 
needed. We are requesting comment about whether we should specifically 
identify such other controls or leave the regulatory text more open 
ended.
    Finally, we are requesting comment about the circumstances under 
which we should allow the AECD to be activated. Should emergency 
situations include only those circumstances where human life is at 
stake? Should it be allowed automatically whenever a federal disaster 
is declared?

VII. Economic, Environmental, and Health Impacts of Proposed Rule

A. Economic Impacts

(1) Economic Impacts of Emergency Vehicle Proposal
    EPA expects the economic effects of this proposal to be small, and 
to potentially have benefits that are a natural result of easing 
constraints.
(a) Costs to Manufacturers
    Due to the optional and voluntary nature of this proposal, 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 would be small, and any variable costs 
would 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 or field modification 
they offer, to offset the costs incurred in its development.
(b) 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.
(i) Maintenance and Warranty Costs
    When an emergency vehicle is experiencing frequent plugging of its 
DPF, this increases maintenance costs for owners and warranty costs for 
manufacturers. Maintenance costs can include service calls for a 
technician-controlled regeneration, towing fees where on-site 
regeneration cannot be achieved, and costs to deploy reserve vehicles 
while the impaired vehicle is being serviced. These costs are expected 
to decrease with this proposal, and are discussed further below.
    Manufacturers incur warranty costs when a vehicle under warranty 
must be returned for service. Because this proposed action would allow 
manufacturers the flexibility to improve the reliability of their 
engines, EPA expects warranty costs for emergency vehicles and engines 
in emergency vehicles would decrease as a result of this action.
    Should an AECD be deployed that allows manual active regenerations 
at more frequent intervals, this could increase the total number of 
regenerations, exposing the DPF substrate to more frequent thermal 
stress and general wear & tear. However, while it is expected that the 
frequency of regenerations would increase, the duration of each 
regeneration would decrease because the total soot loading of the DPF 
would likely remain unchanged or be reduced due to other control 
strategies within the approved AECD. Because manufacturers are held to 
strict standards related to the warranty, maintenance and durability of 
these systems, EPA expects that measures will be taken to ensure that 
any AECD that is deployed would not decrease the ash cleaning interval 
or

[[Page 34170]]

otherwise decrease the durability of the emission control system.\38\
---------------------------------------------------------------------------

    \38\ EPA prohibits engine manufacturers from requiring repair or 
replacement of particulate traps on heavy heavy-duty diesel engines 
more than once every 150,000 miles. 40 CFR 86.004-25(b)(4)(iii).
---------------------------------------------------------------------------

    With this proposal, manufacturers would have the flexibility to 
design alternate calibrations to reduce soot loading to the DPF and 
extend the interval between regenerations. There would also be more 
flexibility to enable more passive and automatic active regenerations, 
which both expose the DPF to less thermal stress than do manual active 
regenerations. In summary, EPA does not expect any warranty or 
maintenance costs would increase due to this proposal, and it is very 
likely that these would decrease. Furthermore, EPA believes that the 
potential for reduced warranty costs may help to offset the cost to 
produce and deploy any optional AECDs. Similarly, EPA believes the 
potential for reduced maintenance and operational costs may offset the 
cost to owners for obtaining requested AECDs.
(ii) Fuel Costs From Dosing
    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. Operators have 
reported that vehicles burn more fuel during regenerations, though the 
quantity varies among vehicles.
    Where automatic active regenerations employ fuel dosing, it is 
uncertain whether fuel consumption would increase with an increased 
number of regenerations during a given operating period. If all else 
were to remain the same, it is likely that the duration of each 
automatic active regeneration may be decreased. 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.
    As an illustration, we have estimated the additional fuel use for a 
truck with a dosing strategy where its regeneration interval is 
decreased from 25 hours to eight hours, due to the increased 
availability of operator-commanded regenerations. In this example, we 
assume a single regeneration consumes approximately half a gallon of 
supplemental fuel. If the vehicle has average engine operating hours of 
1,200 per year, then its number of regeneration events would increase 
from about 50 per year to 150 per year, under the above assumptions. If 
the amount of supplemental fuel use remained unchanged under the new 
regime (a conservative assumption) then potentially the vehicle could 
consume an additional 50 gallons of fuel per year from the increased 
frequency of regenerations alone. Considering current costs of ultra 
low sulfur diesel fuel, this could translate to about $200 per vehicle 
in additional annual fuel costs.
    As explained above, EPA does not believe this is a likely scenario, 
as the amount of fuel used per regeneration event would likely decrease 
with increasing frequency, and engine manufacturers would be likely to 
adjust combustion parameters to avoid placing additional thermal stress 
on the DPF. A more detailed analysis of fuel use and potential costs 
associated with dosing strategies is included in a memo to the docket 
associated with this rulemaking.\39\
---------------------------------------------------------------------------

    \39\ See memo dated May 4, 2012, ``Fuel Use With Dosing for DPF 
Regeneration,'' Docket ID EPA-HQ-OAR-2011-1032.
---------------------------------------------------------------------------

(c) Societal Costs
    Because this proposal 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 
any temporary increase in emissions from this small segment of 
vehicles.
(2) Economic Impacts of SCR Maintenance Proposal
    This action would codify previously published final agency actions 
regarding SCR maintenance intervals. No new regulatory burdens would be 
imposed. Rather, by codifying former decisions that were based on 
administrative petitions and of limited applicability, EPA is providing 
regulatory certainty that will allow affected manufacturers to plan 
their product development accordingly.
(3) Economic Impacts for Nonroad Engines Used in Emergency Situations
    EPA expects the economic effects of this proposal to be small, and 
to potentially have benefits that are a natural result of easing 
constraints. Due to the optional and voluntary nature of this proposal, 
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. We do not expect there to be any operator costs 
for this allowance, other than the potential cost associated with 
sending written confirmation of an emergency situation to the 
certificate holder. However, since this option would be activated 
rarely (or perhaps not at all), total costs to operators would be 
negligible.

B. Environmental Impacts

(1) Environmental Impacts of Emergency Vehicle Proposal
    We expect any environmental impacts from this proposal would be 
small. By promulgating these amendments, it is expected that the 
emissions from this segment of the heavy-duty fleet would not change 
significantly.
(a) Fleet Characterization and Emission Inventory
    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).\40\ 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.
---------------------------------------------------------------------------

    \40\ ICCT, May 2009, ``Heavy-Duty Vehicle Market Analysis: 
Vehicle Characteristics & Fuel Use, Manufacturer Market Shares.''
---------------------------------------------------------------------------

(b) Emission Impacts From Auxiliary Emission Control Devices on 
Emergency Vehicles
    Due to the optional and voluntary nature of this action, it is 
difficult to estimate its overall emissions impact accurately. The 
proposed amendments offer many options to manufacturers, and the 
emissions impacts will depend on which options and strategies are 
employed, and for how many vehicles.
(i) NOX Emissions Impacts
    During both automatic active and manual active regenerations, 
emission rates increase for some pollutants, especially NOX 
when post-DPF after-treatment devices are not present. The

[[Page 34171]]

higher than normal combustion chamber temperatures during active 
regeneration with high rates of oxidation occurring across the catalyst 
can create conditions conducive to NOX formation. From 
certification data for 2008 model year engines, the difference between 
the NOX emission rate during normal operation and the rate 
during active regeneration can range from an undetectably small 
difference to a five-fold increase. The magnitude of the NOX 
increase is only part of the story, however. As part of their 
certifications, engine manufacturers may provide frequency factors that 
adjust for the average excess emissions during DPF regeneration. As 
used in engine certification, the frequency factor indicates the 
percent of test cycles during which DPF regeneration is expected to 
occur. From certification data for 2008 and 2011 model year engines, 
DPF regeneration frequency factors for heavy-duty engines range from 
near zero to nearly 20 percent. Overall, the certification data 
indicate that the higher the increase in NOX during a DPF 
regeneration event, the less often active regeneration occurs on that 
engine, especially over the transient test cycle. A summary of this 
information is presented in a memo to the docket associated with this 
rulemaking.\41\
---------------------------------------------------------------------------

    \41\ See memo dated May 4, 2012, ``NOX Emissions from 
DPF Regeneration,'' Docket ID EPA-HQ-OAR-2011-1032.
---------------------------------------------------------------------------

     As a result of this proposed action, it is possible that some 
engine manufacturers will submit applications for AECD's with 
liberalized parameters under which automatic active and/or manual 
active regenerations may occur, for emergency vehicles. Under these 
liberalized parameters, several outcomes are possible, depending on the 
engineering design. While the NOX emission rate during DPF 
regeneration could increase above the rate of the current certified 
configuration, it is also possible that the duration of each event 
could decrease. While the frequency of manual active regenerations 
could increase if the engine controls permitted operators to initiate 
parked regeneration at any soot loading, it is also possible the 
frequency of automatic or manual active regenerations could decrease 
with the new designs, making wider use of passive regeneration 
strategies. Given that it is difficult to estimate how popular each 
option may be, and what other actions may be taken to alter engines 
and/or emission control systems, EPA has provided examples of possible 
emission scenarios due to this proposal in a memo to the docket.\42\
---------------------------------------------------------------------------

    \42\ See NOX Memo, Note 41, above.
---------------------------------------------------------------------------

(ii) PM Emissions Impacts
    In the comment letters EPA received urging swift action providing 
relief for emergency vehicles, it was often cited that the pollution 
from a structural fire is far worse than the tailpipe emissions of a 
fire truck. To provide some perspective on this, EPA is providing a 
brief discussion of PM emissions in this section.
    A rough method for estimating emissions from structural fires is 
obtained by multiplying a national average factor of 2.3 fires per 
1,000 residents by the national population, along with a PM emission 
factor of 10.8 lb per ton burned, and an average fuel loading of 1.1 
tons burned per fire. Using these estimates, EPA calculates just under 
5,000 tons of PM is emitted in the U.S. each year from structural 
fires. A more detailed analysis of PM emissions from structural fires 
in relation to PM emissions from emergency vehicles is included in a 
memo to the docket associated with this rulemaking.\43\
---------------------------------------------------------------------------

    \43\ See Memo dated May 4, 2012, ``PM Emissions Impacts,'' 
Docket ID EPA-HQ-OAR-2011-1032.
---------------------------------------------------------------------------

    We expect manufacturers who choose to develop optional AECDs for 
emergency vehicles to employ strategies that prevent the occurrence of 
abnormal conditions of the emission control system. Where preventive 
strategies alone are not demonstrated to be failsafe, EPA expects there 
may be instances where it is justified to provide engine exhaust 
backpressure relief, either mechanical or through other means. While we 
expect this will not be a widespread solution, there may be cases where 
a relief valve may be employed on a vehicle whose DPF became plugged 
frequently, allowing temporary emission control bypass to occur as a 
last resort to prevent engine failure. An example of possible PM 
emissions changes due to this proposal is presented in a memo to the 
docket associated with this rulemaking.\44\
---------------------------------------------------------------------------

    \44\ See PM memo, Note 43, above.
---------------------------------------------------------------------------

(iii) Fuel Use From Dosing
    As described above in Section IV.C, only some control systems 
employ fuel dosing as a strategy to initiate active regeneration. In a 
memo to the docket associated with this rulemaking, EPA estimates the 
potential increase in fuel use due to more frequent operator-commanded 
regenerations with dosing at an average of about 50 gallons per year 
per vehicle, if other measures to reduce the need for regenerations are 
not taken.\45\ The emissions associated with this supplemental fuel use 
are discussed above. EPA requests comment on the impact of this 
proposed action on fuel consumption in emergency vehicles whose active 
regeneration strategies include fuel dosing.
---------------------------------------------------------------------------

    \45\ See Fuel Dosing Memo, Note 39, above.
---------------------------------------------------------------------------

(2) Environmental Impacts of SCR Maintenance Proposal
    EPA believes that the likelihood of emissions-related maintenance 
occurring in use would remain unchanged as a result of this action. 
Therefore, there are no anticipated adverse environmental impacts.
(3) Environmental Impacts for Nonroad Engines Used in Emergency 
Situations
    EPA does not expect any significant environmental effects as a 
result this proposal. This option would be activated rarely (or perhaps 
not at all) and would only affect emissions for a very short period.

C. 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 proposed 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.

VIII. Public Participation

    We request comment by July 27, 2012 on all aspects of this 
proposal. This section describes how you can participate in this 
process.

[[Page 34172]]

A. How do I submit comments?

    We are opening a formal comment period by publishing this document. 
We will accept comments through July 27, 2012. If you have an interest 
in the program described in this document, we encourage you to comment 
on any aspect of this rulemaking. We request comment on various topics 
throughout this proposal.
    Your comments will be most useful if you include appropriate and 
detailed supporting rationale, data, and analysis. If you disagree with 
parts of the proposed program, we encourage you to suggest and analyze 
alternate approaches to meeting the goals described in this proposal. 
You should send all comments, except those containing proprietary 
information, to our Air Docket (see ADDRESSES) before the end of the 
comment period.
    If you submit proprietary information for our consideration, you 
should clearly separate it from other comments by labeling it 
``Confidential Business Information (CBI).'' You should send CBI 
directly to the contact person listed under FOR FURTHER INFORMATION 
CONTACT instead of the public docket. This will help ensure that no one 
inadvertently places proprietary information in the docket. If you want 
us to use your confidential information as part of the basis for the 
final rule, you should send a non-confidential version of the document 
summarizing the key data or information. We will disclose information 
covered by a claim of confidentiality only through the application of 
procedures described in 40 CFR part 2. If you do not identify 
information as confidential when we receive it, we may make it 
available to the public without notifying you.
    EPA is also publishing a Direct Final Rule (DFR) addressing the 
emergency vehicle provisions described in Section IV of this document. 
If we receive adverse comments on the emergency vehicle provisions in 
this proposal by July 9, 2012, we will publish a timely withdrawal in 
the Federal Register informing the public that the direct final rule 
will not take effect, and we will complete the process of responding to 
comments and issuing a final rule.
    EPA is publishing the DFR 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 emergency vehicle proposed action described in Section IV above 
with which you agree and support as proposed, 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 the DFR 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.
    Note that Docket Number EPA-HQ-OAR-2011-1032 is being used for both 
the DFR and this Notice of Proposed Rulemaking (NPRM).

B. Will there be a public hearing?

    We will hold a public hearing at the EPA's National Vehicle and 
Fuels Emission Laboratory, 2565 Plymouth Road in Ann Arbor, Michigan on 
June 27, 2012. The hearing will start at 10:00 a.m. and continue until 
everyone has had a chance to speak.
    If you would like to present testimony at the public hearing, we 
ask that you notify the contact person listed above under FOR FURTHER 
INFORMATION CONTACT at least ten days before the hearing. You should 
estimate the time you will need for your presentation and identify any 
needed audio/visual equipment. We suggest that you bring copies of your 
statement or other material for the EPA panel and the audience. It 
would also be helpful if you send us a copy of your statement or other 
materials before the hearing.
    We will make a tentative schedule for the order of testimony based 
on the notifications we receive. This schedule will be available on the 
morning of the hearing. In addition, we will reserve a block of time 
for anyone else in the audience who wants to give testimony. We will 
conduct the hearing informally, and technical rules of evidence won't 
apply. We will arrange for a written transcript of the hearing and keep 
the official record of the hearing open for 30 days to allow you to 
submit supplementary information. You may make arrangements for copies 
of the transcript directly with the court reporter.

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory 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 proposed regulatory relief for emergency vehicles would be 
voluntary and optional, and the proposed revisions for engine and 
vehicle maintenance would 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 proposed rule on

[[Page 34173]]

small entities, I certify that proposed rule would 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 proposed rule provides regulatory relief related to emergency 
vehicles and codifies existing guidelines related to engine and vehicle 
maintenance. 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 proposal contains no Federal mandates under the regulatory 
provisions of Title II of the UMRA for State, local, or tribal 
governments. The proposal imposes no enforceable duty on any State, 
local or tribal governments. EPA has determined that this proposal 
contains no regulatory requirements that might significantly or 
uniquely affect small governments. The agency has determined that this 
proposal does not contain a Federal mandate that may result in 
expenditures of $100 million or more for the private sector in any one 
year. Manufacturers have the flexibility and will likely choose whether 
or not to use optional AECD's based on their strategies for complying 
with the applicable emissions standards. Similarly, manufacturers may 
choose to use DEF maintenance intervals longer than the minimums 
proposed in this action, and manufacturers may elect to use SCR 
strategies that consume lower amounts of DEF. Thus, today's proposal is 
not subject to the requirements of sections 202 and 205 of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that 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.''
    This proposed 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 proposed rule would apply 
to manufacturers of heavy-duty diesel engines and not to state or local 
governments. Thus, Executive Order 13132 does not apply to this action.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between the agency and State and local 
governments, the agency specifically solicits comment on this proposed 
action from State and local officials.

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 proposal 
will be implemented at the Federal level and would impose compliance 
costs only on affected engine manufacturers depending on the extent to 
which they take advantage of the flexibilities offered. Tribal 
governments would be affected only to the extent they purchase and use 
vehicles with regulated engines. Thus, Executive Order 13175 does not 
apply to this proposed rule. EPA specifically solicits additional 
comment on this proposed action from tribal officials.

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 proposed rule is not 
subject to Executive Order 13045 because it does not establish an 
environmental standard intended to mitigate health or safety risks.

H. Executive Order 13211: Energy Effects

    This proposed 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 
is not considering 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 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

[[Page 34174]]

populations and low-income populations in the United States.
    EPA has determined that this proposed rule would not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations. This action is expected 
to increase the level of environmental protection for all affected 
populations because this proposed rule increases the ways that 
manufacturers can demonstrate compliance with heavy-duty engine 
standards.

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 proposes to amend title 40, chapter I of the Code of 
Federal Regulations as follows:

PART 85--CONTROL OF AIR POLLUTION FROM MOBILE SOURCES

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

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

Subpart R--[Amended]

    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

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

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

Subpart A--[Amended]

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

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

[[Page 34175]]

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.
* * * * *
    5. Section 86.004-25 is amended as follows:
    a. By revising paragraph (b)(4) introductory text.
    b. By adding paragraph (b)(4)(v).
    c. By revising paragraph (b)(6)(i) introductory text and 
(b)(6)(i)(H).
    d. By adding paragraph (b)(6)(i)(I).

Sec.  86.004-25   Maintenance.

* * * * *
    (b) * * *
    (4) For diesel-cycle heavy-duty engines, emission-related 
maintenance in addition to or at shorter intervals than the following 
specified values will not be accepted as technologically necessary, 
except as provided in paragraph (b)(7) of this section:
* * * * *
    (v) For engines that use selective catalytic reduction, the 
replenishment of diesel exhaust fluid shall occur according to the 
following schedule:
    (A) For heavy-duty engines in vocational vehicles such as dump 
trucks, concrete mixers, refuse trucks and similar applications that 
are typically centrally fueled, at an interval, in miles or hours of 
vehicle operation, that is no less than the vehicle's fuel capacity.
    (B) For all other heavy-duty engines, at an interval, in miles or 
hours of vehicle operation, that is no less than twice the vehicle's 
fuel capacity.
* * * * *
    (6)(i) The following components are defined as critical emission-
related components:
* * * * *
    (H) Components comprising the selective catalytic reduction system 
(including diesel exhaust fluid tank).
    (I) Any other component whose primary purpose is to reduce 
emissions or whose failure would commonly increase emissions of any 
regulated pollutant without significantly degrading engine performance.
* * * * *
    6. Section 86.0004-28 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'' in Sec.  86.004-2, do not 
consider additional regenerations resulting from those AECDs when 
calculating emission factors or frequencies under this paragraph (i).
* * * * *
    7. 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]

    8. 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'' in Sec.  86.004-2. The emission standards do not 
apply when any of these AECDs are active.

Subpart N--[Amended]

    9. 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.
    10. 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.  
86.004-2, the NTE emission limits do not apply when any of these AECDs 
are active.

Subpart S--[Amended]

    11. Section 86.1803-01 is amended as follows:
    a. By adding a definition for ``Ambulance'' in alphabetical order.
    b. By revising the definition for ``Defeat device''.
    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;

[[Page 34176]]

    (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.
* * * * *
    12. 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.''
    13. Subpart S is amended by removing Sec.  86.1807-07.

Sec.  86.1807-07  [Removed]

    14. Section 86.1834-01 is amended as follows:
    a. By revising paragraph the introductory text of (b)(4).
    b. By adding paragraph (b)(4)(iii).
    c. By revising paragraph (b)(6)(i)(H).
    d. By adding paragraph (b)(6)(i)(I).

Sec.  86.1834-01  Allowable maintenance.

* * * * *
    (b) * * *
    (4) For diesel-cycle vehicles, emission-related maintenance in 
addition to, or at shorter intervals than the following will not be 
accepted as technologically necessary, except as provided in paragraph 
(b)(7) of this section:
* * * * *
    (iii) For vehicles that use selective catalytic reduction, the 
replenishment of diesel exhaust fluid shall occur at an interval, in 
miles or hours of vehicle operation, that is no less than the scheduled 
oil change interval.
* * * * *
    (6) * * *
    (i) * * *
    (H) Components comprising the selective catalytic reduction system 
(including diesel exhaust fluid tank).
    (I) Any other component whose primary purpose is to reduce 
emissions or whose failure would commonly increase emissions of any 
regulated pollutant without significantly degrading engine performance.
* * * * *
    15. 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

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

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

Subpart B--[Amended]

    17. 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.
    18. Section 1039.125 is amended by adding paragraphs (a)(2)(iii) 
and (a)(3)(iii) to read as follows:

Sec.  1039.125   What maintenance instructions must I give to buyers?

* * * * *
    (a) * * *
    (2) * * *
    (iii) For SCR systems, the minimum interval for replenishing the 
diesel exhaust fluid is the number of engine operating hours necessary 
to consume a full tank of fuel based on normal usage starting from full 
fuel capacity for the equipment.
    (3) * * *
    (iii) For SCR systems, the minimum interval for replenishing the 
diesel exhaust fluid is the number of engine operating hours necessary 
to consume a full tank of fuel based on normal usage starting from full 
fuel capacity for the equipment.
* * * * *
    19. Section 1039.130 is amended by revising paragraph (b)(3) to 
read as follows:

Sec.  1039.130  What installation instructions must I give to equipment 
manufacturers?

* * * * *
    (b) * * *
    (3) Describe the instructions needed to properly install the 
exhaust system and any other components. Include instructions 
consistent with the requirements of Sec.  1039.205(u). Also describe 
how to properly size diesel

[[Page 34177]]

exhaust fluid reservoirs consistent with the specifications in Sec.  
1039.125(a) if applicable.
* * * * *
    20. 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]

    21. 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).
    22. 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]

    23. Add Sec.  1039.665 to subpart G to read as follows:

Sec.  1039.665  Special provisions for use of engines in emergency 
situations.

    This section specifies provisions that allow for AECDs that are 
necessary to ensure proper functioning of engines and equipment 
regulated under this part in emergency situations. For purposes of this 
section, an emergency situation is one in which the functioning (or 
malfunctioning) of emission controls poses a significant risk to human 
life. For example, a situation in which a feature of emission controls 
inhibits the performance of an engine being used to rescue a person 
from a life-threatening situation would be an emergency situation. 
AECDs approved under this section are not defeat devices.
    (a) Manufacturers may ask for approval under this section at any 
time; however, we encourage manufacturers to obtain preliminary 
approval before submitting an application for certification. We may 
allow manufacturers to apply an approved emergency AECD to engines and 
equipment that have already been placed into service.
    (b) We will approve an AECD where we determine the following 
criteria are met:
    (1) Activation of the AECD cannot occur without the specific 
permission of the certificate holder, and must require the input of a 
temporary code or equivalent security feature.
    (2) The AECD must become inactive within 24 engine hours of 
becoming active.
    (3) The AECD may deactivate emission controls as necessary to 
address the emergency situation. For purposes of this paragraph (b)(3), 
inducement strategies related to operating SCR-equipped engines without 
reductant are considered to be emission controls.
    (4) The AECD's design is consistent with good engineering judgment.
    (c) The certificate holder must keep records to document requests 
for and use of emergency AECDs under this section.
    (1) The operator (or other person responsible for the engine/
equipment) must send a written request to the certificate holder prior 
to use, or a written confirmation of a verbal request within 30 days of 
making the request, including a description of the emergency situation, 
the reason for the use of the AECD, and a signature from an official 
acknowledging the conditions of the emergency situation (such as a 
county sheriff, fire marshal, or hospital administrator). Such requests 
are deemed to be submissions to EPA. Where written confirmation is not 
submitted by the operator, we will deem operation of the engine with an 
activated emergency AECD to be a violation of 40 CFR 1068.101(b)(1).
    (2) If the operator does not submit the applicable confirmation 
within 30 days, the certificate holder must send written notification 
to the operator that failure to submit written confirmation may subject 
the operator to penalties under 40 CFR 1068.101.
    (3) Within 60 days of the end of each calendar year in which the 
certificate holder authorizes use of the AECD, the certificate holder 
must send a report to the Designated Compliance Officer to summarize 
such use, including a description of the emergency situation 
precipitating each use, and copies of the written confirmation provided 
by operators (or statements that the operator did not provide 
confirmation). We may require more frequent reporting if we find that 
the certificate holder does not collect or attempt to collect written 
confirmation for each situation.
    (d) We may set other reasonable conditions to ensure that this 
provision is not used to circumvent the emission standards of this 
part.
    24. 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

[[Page 34178]]

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 
such abnormal conditions from occurring, during operation related to 
emergency response.
    (iii) Unless we say otherwise, your proposed EEFM 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 EEFM is deemed to be approved under paragraph 
(c)(2) or (3) of this section and we find later that your EEFM in fact 
does not meet the requirements of this section, we may require you to 
no longer install or distribute it.

Subpart I--[Amended]

    25. Section 1039.801 is amended by adding definitions for ``Diesel 
exhaust fluid'' and ``Emergency equipment'' in alphabetical order to 
read as follows:

Sec.  1039.801  What definitions apply to this part?

* * * * *
     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 equipment means either of the following types of 
equipment:
    (1) Specialized vehicles used to perform aircraft rescue and fire-
fighting functions at airports, with particular emphasis on saving 
lives and reducing injuries coincident with aircraft fires following 
impact or aircraft ground fires.
    (2) Wildland fire apparatus, which includes any apparatus equipped 
with a slip-on fire-fighting module, designed primarily to support 
wildland fire suppression operations.
* * * * *
    26. Section 1039.805 is amended by adding abbreviations for 
``DEF'', ``EEFM'', ``ISO'', and ``SCR'' in alphabetical order to read 
as follows:

Sec.  1039.805  What symbols, acronyms, and abbreviations does this 
part use?

* * * * *
    DEF Diesel exhaust fluid.
    EEFM Emergency equipment field modification.
* * * * *
    ISO International Organization for Standardization (see 
www.iso.org).
* * * * *
    SCR Selective catalytic reduction.
* * * * *
[FR Doc. 2012-13087 Filed 6-7-12; 8:45 a.m.]
BILLING CODE 6550-50-P
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