1

 

 

MEMORANDUM

Subject: Response to Public Comments on Proposed Amendments to the Standards of 

Performance for Stationary Compression Ignition and Spark Ignition Internal 

Combustion Engines 

From: Melanie King, Energy Strategies Group 

 

To: EPA Docket EPA-HQ-OAR-2010-0295 

On June 8, 2010, EPA proposed amendments to the standards of performance for stationary 

compression ignition (CI) and spark ignition (SI) internal combustion engines in 40 CFR part 60, 

subparts IIII and JJJJ. The purpose of this document is to present a summary of the public 

comments that EPA received on the proposed standards and the responses developed. This 

summary of comments and responses serves as the basis for revisions made to the requirements 

between proposal and promulgation. 

EPA received 32 public comments on the proposed rule. A listing of all persons submitting 

comments, their affiliation, and the Document ID for their comments is presented in Table 1. 

The comments can be obtained online from the Federal Docket Management System at 

http://www.regulations.gov. The docket number for this rulemaking is EPA-HQ-OAR-2010-

0295. In this document, commenters are identified by the last two digits of the Document ID of 

their comments. 
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Table 1. List of Commenters on the Proposed Amendments to Standards of Performance for 

Stationary CI and SI Internal Combustion Engines 

Document ID Commenter/Affiliation

EPA-HQ-OAR-2010-0295-0021 Dan Chisholm Sr. 

MGI Systems, Inc. 

EPA-HQ-OAR-2010-0295-0022 

EPA-HQ-OAR-2010-0295-0055 

Matt Todd 

Policy Advisor 

American Petroleum Institute 

EPA-HQ-OAR-2010-0295-0023 

EPA-HQ-OAR-2010-0295-0053 

Alice Edwards 

Acting Director, Division of Air Quality 

State of Alaska Department of Environmental Conservation, Division of 

Air Quality 

EPA-HQ-OAR-2010-0295-0024 

Don C. DiCristofaro 

President 

Blue Sky Environmental, LLC 

EPA-HQ-OAR-2010-0295-0026 

Dan E. Brann 

Manager, Emissions Compliance 

Electro-Motive Diesel, Inc. 

EPA-HQ-OAR-2010-0295-0027 

James L. Kavanaugh 

Director 

State of Missouri Department of Natural Resources 

EPA-HQ-OAR-2010-0295-0028 

EPA-HQ-OAR-2010-0295-0029 

(duplicative comment) 

EPA-HQ-OAR-2010-0295-0045 

Ali Mirzakhalili 

Director 

State of Delaware Department of Natural Resources and Environmental 

Control Division of Air Quality 

EPA-HQ-OAR-2010-0295-0030 

EPA-HQ-OAR-2010-0295-0052 

Rich Counihan 

Enernoc (on behalf of CPower, Inc., EnergyConnect, Inc., EnerNOC, 

Inc., Innoventive Power LLC. 

EPA-HQ-OAR-2010-0295-0031 

Don Mark Anthony 

Air Quality Engineer 

Alyeska Pipeline Service Company 

EPA-HQ-OAR-2010-0295-0032 

Allen Gillette 

Senior Vice President of Engineering 

Generac Power Systems, Inc. 

EPA-HQ-OAR-2010-0295-0033 

John S. Lyons 

Director 

Commonwealth of Kentucky Energy and Environment Cabinet 

Department for Environmental Protection Division of Air Quality 

EPA-HQ-OAR-2010-0295-0034 David Meierhenry 

EPA-HQ-OAR-2010-0295-0035 Jim Moxley 

Healthsouth 

EPA-HQ-OAR-2010-0295-0036 

Joseph Kubsh 

Executive Director 

Manufacturers of Emission Controls Association 
3

Document ID Commenter/Affiliation

EPA-HQ-OAR-2010-0295-0037 

EPA-HQ-OAR-2010-0295-0057 

 

Timothy A. French 

General Counsel 

Joseph L. Suchecki 

Director, Public Affairs 

Engine Manufacturers Association 

EPA-HQ-OAR-2010-0295-0038 

Bill Wemhoff 

Sr. Principal, Environmental Policy 

National Rural Electric Cooperative Association 

EPA-HQ-OAR-2010-0295-0039 

Mark Underhill 

Emissions Specialist 

Foley Engine Systems 

EPA-HQ-OAR-2010-0295-0040 

Supports the comments of 

EPA-HQ-OAR-2010-0295-0037 

Brady Winkleman 

Caterpillar, Inc. 

EPA-HQ-OAR-2010-0295-0041 

Arthur W. Iler 

Assistant General Counsel 

Midwest Independent Transmission System Operator, Inc. 

EPA-HQ-OAR-2010-0295-0042 

William M. Nugent 

Executive Director 

New England Conference of Public Utility Commissioners 

EPA-HQ-OAR-2010-0295-0043 

Lisa Beal 

Director, Environment and Construction Policy 

Interstate Natural Gas Association of America 

EPA-HQ-OAR-2010-0295-0044 

Anna Garcia 

Executive Director 

Ozone Transport Commission 

EPA-HQ-OAR-2010-0295-0046 

Mike Wasson 

Director, North America Fleet Services 

Exterran 

EPA-HQ-OAR-2010-0295-0047 

Jack Mitchell 

Senior Consultant 

Trinity Consultants 

EPA-HQ-OAR-2010-0295-0048 

Cynthia A. Finley 

Director, Regulatory Affairs 

National Association of Clean Water Agencies 

EPA-HQ-OAR-2010-0295-0049 

Kate Williams 

Regulatory Affairs Representative 

Alaska Oil and Gas Association 

EPA-HQ-OAR-2010-0295-0050 

John Dutton 

GCA HSE Committee Chairman 

Gas Compressor Association 
4

Document ID Commenter/Affiliation

EPA-HQ-OAR-2010-0295-0051 

Support the comments of 

EPA-HQ-OAR-2010-0295-0050 

EPA-HQ-OAR-2010-0295-0055 

John Dutton 

Manager of Operations 

J-W Power Company 

EPA-HQ-OAR-2010-0295-0054 

Support the comments of 

EPA-HQ-OAR-2010-0295-0055 

Dan F. Hunter 

Manager, Regulatory Issues 

ConocoPhillips 
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Summary of Public Comments and Responses

The summary of public comments and responses is organized as follows: 

1.0 General 

2.0 10-30 Liters/Cylinder Displacement Engines 

3.0 ≥30 Liters/Cylinder Displacement Engines 

4.0 Operating and Maintenance Requirements 

5.0 Alaska 

6.0 Temporary, Replacement, and Marine Engines 

7.0 Digester Gas Engines 

8.0 Test Methods 

9.0 Definitions 

9.1 Reconstruction 

9.2 Date of Manufacture 

9.3 Installed 

9.4 Certified Emissions Life 

9.5 Emergency Engines 

9.6 Freshly Manufactured Engines 

10.0 Miscellaneous 
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1.0 General 

1.1 Comment: Two commenters (22 and 23) requested that EPA provide additional time to 

submit comments on the proposed amendments to 40 CFR part 60, subparts IIII and JJJJ. 

Commenter 22 specifically asked that EPA provide a 30-day extension period for providing 

comments. 

Response: EPA provided a 30-day extension to the public comment period to allow additional 

time for commenters to prepare and submit their comments.

1.2 Comment: One commenter (37) expressed general support of EPA’s proposed amendments 

to 40 CFR part 60, subparts IIII and JJJJ. Specifically, commenter 37 said that the changes 

proposed by EPA are positive because they generally provide more flexibility and address 

various issues associated with the regulations as they currently exist. 

Response: No response is needed. 

1.3 Comment: One commenter (33) indicated that there is confusion regarding the applicability 

of 40 CFR part 60, subpart JJJJ and 40 CFR part 63, subpart ZZZZ, to new stationary SI 

emergency engines. The commenter (33) said that 63.6590(c) of the final National Emission 

Standards for Hazardous Air Pollutants (NESHAP) is confusing and the commenter (33) believes 

the paragraph contradicts the New Source Performance Standards (NSPS) for stationary SI 

engines. For example, the commenter’s (33) understanding per 63.6590(c) is that an emergency 
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SI engine built in 2007 could comply with the NESHAP by meeting the requirements in the SI 

NSPS. However, the commenter (33) believes this contradicts 40 CFR part 60, subpart JJJJ, 

because new emergency SI engines built in 2007 are not subject to this regulation according to 

60.4230(a)(4)(iv). The commenter (33) said that emergency SI engines constructed between 

June 12, 2006, and before January 1, 2009, are not subject to 40 CFR part 60, subpart JJJJ, and 

consequently are not subject to any requirements. The commenter (33) argued that 40 CFR part 

60, subpart JJJJ should require these engines and other engines that are not subject to any 

requirements to at least meet work practice standards. Additionally, commenter 33 expressed 

that emergency engines should be subject to the same operational limitations as other emergency 

engines that are subject to 40 CFR part 60, subpart JJJJ. 

Response: Stationary SI engines less than or equal to 500 horsepower (HP) that are located at 

major sources of hazardous air pollutant (HAP) emissions and stationary SI engines of any size 

that are located at area sources of HAP emissions that are considered new under 40 CFR part 63, 

subpart ZZZZ, but that pre-date NSPS applicability under 40 CFR part 60, subpart JJJJ, are not 

subject to any requirements. However, revisions to the substance of 40 CFR part 60, subpart JJJJ 

are beyond the scope of this rule, which deals primarily with revisions to 40 CFR part 60, 

subpart IIII and merely includes some minor revisions to 40 CFR part 60, subpart JJJJ to be 

consistent with the changes made to 40 CFR part 60, subpart IIII and to correct minor errors. 

EPA intends to address this issue during EPA’s review of 40 CFR part 60, subpart JJJJ in the 

near future. 

 
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1.4 Comment: One commenter (39) indicated that it would be beneficial if EPA published 

material that could be used to calculate costs for determining rebuild costs to compare to the 

costs of a new engine. Specifically, commenter 39 suggested that a spreadsheet could be made 

available, which could be used as a template for this purpose. Such a tool would ensure 

regulation consistency and eliminate confusion because there are currently numerous different 

interpretations of the requirements, according to the commenter (39). 

Response: EPA is not developing such material at this time, but will consider providing 

guidance material in the future 

1.5 Comment: One commenter (44) recommended that EPA limit the sulfur content in the fuel 

to 15 parts per million (ppm) for stationary engines as soon as possible, as is currently required 

for on-road and nonroad engines. This would be consistent with the Northeast and Mid-Atlantic 

States’ commitment to pursue low sulfur in fuel limits to assist in reaching State implementation 

plans regional haze goals.

Response: 40 CFR part 60, subpart IIII already limits the sulfur content in diesel fuel to 15 ppm 

for the majority of engines subject to the NSPS. 

1.6 Comment: One commenter (44) said that the standards being proposed for stationary engines 

should be consistent with the standards that have already been finalized for nonroad engines. In 

addition, the commenter (44) recommended that these standards apply to portable engines that 
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remain on site for more than 30 days and does not believe these engines should be considered 

portable engines.

Response: EPA’s approach is designed exactly according to what the commenter is requesting 

and EPA agrees with the commenter that the standards should be consistent with nonroad 

standards for similar engines. Regarding the commenter’s recommendation for portable engines 

that remain on site for more than 30 days, the definition of nonroad engine requires that a 

portable engine be at a non-seasonal location for at least a year before it is considered stationary. 

That is a longstanding definition that was not revisited in this rule and is beyond its scope. Also, 

the commenter did not provide any reasons for changing this longstanding definition. 

1.7 Comment: One commenter (44) suggested that the final rule include additional provisions 

that are being considered to be included in the Ozone Transport Commission model rule, which 

is currently being drafted. The suggested provisions include monitoring and data reporting on 

generator usage, combined heat and power incentives and innovative technologies, and 

emissions standards for demand response programs, the commenter (44) said. 

Response: These comments are not in the scope of the rulemaking and have not been provided 

with enough specificity to take any further action. 

1.8 Comment: One commenter (38) cited to several rulemakings EPA has promulgated over the 

years for stationary internal combustion engines under sections 111 and 112 of the Clean Air Act 

(CAA). The commenter (38) expressed that there are inconsistencies between the various rules 
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and there is confusion among the regulated community. The commenter (38) acknowledged in 

its comments that EPA has attempted to provide some consistency between regulations, e.g., by 

EPA’s proposal to revise the emergency engine definition. The commenter (38) requested that 

consistency be provided for engines under 40 CFR part 63, subpart ZZZZ, and referred to the 

subcategory of existing non-emergency SI engines that operate 24 hours of less per year that was 

included in the August 2010 amendments to that subpart. Those engines may comply with work 

practices, the commenter (38) said, and the commenter (38) believes that it would be justified to 

also establish an equivalent subcategory for stationary non-emergency CI engines that operate 24 

hours or less per year. According to the commenter (38), stationary CI engines that operate 24 

hours or less per year emit low emissions and can be used in situations that are not allowed if the 

engines were considering emergency engines. The commenter (38) requested that EPA add this 

provision to the final rule, or alternatively address this issue under the stationary CI 

reconsideration. 

Response: Amendments to 40 CFR part 63, subpart ZZZZ are outside the scope of this 

rulemaking. 

2.0 10-30 Liters/Cylinder Displacement Engines

2.1 Comment: Several commenters (26, 36, 37, and 44) indicated that they agree that it is 

appropriate to extend the nonroad engine standards that were recently finalized to stationary CI 

engines with a displacement between 10 and 30 liters per cylinder (l/cyl). 

 Commenter 26 also supported EPA’s proposed changes to incorporate 40 CFR part 1042 

under the 60.4201 and 60.4202 of the CI NSPS and apply those requirements to appropriate 
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displacement stationary engines. In the commenter’s (26) opinion, if this provision is finalized it 

will result in significant emissions reductions at a low cost. 

Response: No response is needed. 

2.2 Comment: One commenter (37) said that 60.4201 of the proposed CI NSPS is correct, but 

that Table 2 in the preamble to the proposed rule is not accurate. According to commenter 37 

there are no Tier 3 particulate matter (PM) standards for marine engines between 15 and 30 l/cyl 

that are above 2,000 kilowatt (KW), but there are Tier 3 nitrogen oxides (NOx) standards for 

marine engines between 7 and 15 l/cyl. EPA should correct Table 2 of the preamble to match the 

rule, the commenter (37) said. 

 The commenter (37) also indicated that section 60.4202(f) of the proposed rule that 

contains requirements for stationary emergency CI engines between 10 and 30 l/cyl is incorrect. 

Commenter 37 said that EPA refers to Tier 3 emission standards in that section, but there are no 

Tier 3 emission standards for comparable marine engines. According to the commenter (37), 40 

CFR part 1042, which is the section that EPA cites in 60.4202(f) of the proposed rule, 

specifically excludes all marine CI engines above 3,700 KW as well as marine CI engines above 

2,000 KW with displacements between 15 and 30 l/cyl from Tier 3 standards. Therefore, the 

commenter (37) said, the standards that EPA cites in 60.4202(f) of the proposed rule do not exist. 

The commenter (37) reiterated why EPA determined that there should be no Tier 3 standards for 

similarly sized marine CI engines under the marine rule and that it agreed with that previous 

determination. The commenter (37) asked that EPA correct the section in question in the 
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proposed rule and state in the final rule that stationary emergency CI engines under 60.4202(f) 

meet Tier 2 and not Tier 3 marine engine standards. 

Response: EPA agrees with the commenter and notes that there were inadvertent errors in the 

preamble and regulatory language of the proposed rule. On the first issue regarding the 

standards being presented incorrectly in the preamble to the proposed rule, EPA concurs with the 

commenter. The Tier 3 standards are correctly laid out in the final preamble and are also shown 

in Table 2 below. 

Table 2. First Tier of Standards for Stationary CI Engines 

with a Displacement ≥10 and <30 Liters per Cylinder

Engine Size – Liters per Cylinder, 

Maximum Engine Power 

PM 

g/HP-hr 

(g/KW-hr) 

NOx+HC 

g/HP-hr 

(g/KW-hr) 

Model Year 

10.0≤displacement<15.0 

<2,000 KW 

0.10 

(0.14) 

4.6 

(6.2) 2013+ 

10.0≤displacement<15.0 

2,000≤KW<3,700 

0.10 

(0.14) 

5.8 

(7.8) 2013+ 

15.0≤displacement<20.0 

<2,000 KW 

0.25 

(0.34) 

5.2 

(7.0) 2014+ 

20.0≤displacement<25.0 

<2,000 KW 

0.20 

(0.27) 

7.3 

(9.8) 2014+ 

25.0≤displacement<30.0 

<2,000 KW 

0.20 

(0.27) 

8.2 

(11.0) 2014+ 

On the second issue regarding the standards in section 60.4202(f) of the proposed rule 

being incorrect, the commenter is correct and EPA agrees that the same standards that apply to 

marine CI engines should apply to stationary CI emergency engines that have the same size and 

displacement. Tier 2 emission standards should apply to these engines where there are no Tier 3 
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marine engine standards for comparable engines. Subsequently, EPA is including language in 

the final rule that clarifies this. 

2.3 Comment: One commenter (37) asked that EPA harmonize the displacement (l/cyl) cutoff 

between medium speed and high speed stationary engines. Commenter 37 recommended that 

EPA change the displacement threshold where stationary engines have to meet marine engine 

standards from 10 l/cyl to 7 l/cyl. The commenter (37) believes that most if not all engines with 

a displacement from 7 to 10 l/cyl are produced for marine purposes and for that reason suggested 

that the displacement threshold be aligned.

 One commenter (37) asked that EPA provide 4 years of lead time from promulgation of 

the CI NSPS until the standards phase-in. According to the commenter (37), medium speed 

marine and stationary engines have similar designs, but generally require separate development 

programs based on certain differences. 

Response: The standards for marine engines of 7 l/cyl to 10 l/cyl displacement are not as 

stringent as the standards that have already been in place for several years for stationary engines 

with a displacement of 7 l/cyl to 10 l/cyl. The commenter did not provide compelling 

information to justify reducing the stringency of the standards for stationary engines of this size 

range. 

3.0 ≥30 Liters/Cylinder Displacement Engines

3.1 Comment: Three commenters (36, 37, and 44) indicated that they are supportive of the 

proposed amendments, which more closely align emission standards for stationary CI engines 
14

with a displacement of 30 l/cyl and above with those that apply to similar nonroad engines. EPA 

proposed this change in 60.4204 and 60.4215 of 40 CFR part 60, subpart IIII. The commenter 

(37) said that the current limits, which are either emission standards or percent reduction limits, 

are not necessarily technically or economically feasible for these engines. The current 

requirements put engines with a displacement at or above 30 l/cyl at a disadvantage 

economically in comparison to other large engines or combustion technologies, according to the 

commenter (37). The commenter (37) said that finalizing emission standards for large 

displacement engines that are more consistent with the International Maritime Organization 

(IMO) marine engine standards, will mean that the standards are technically and economically 

feasible and would allow the lead time necessary to implement appropriate emissions control 

technologies for these engines. Large displacement stationary engines are derived from marine 

engines, but generally have different turbo specifications because of different loading 

optimization needs, the commenter (37) said. 

Response: No response is needed. 

 

3.2 Comment: One commenter (37) said that in the final rule EPA needs to add stipulated 

allowances from sections 6.3.11 and 6.4.13 of the IMO Marine Environment Protection 

Committee (MEPC) 58 Revised ANNEX VI from October 2008 to sections 60.4204 and 60.4215 

of the rule. 

Response: EPA contacted the commenter for additional information on what the IMO 

allowances are and what the commenter is requesting that EPA allow for stationary CI engines 
15

with a displacement of 30 l/cyl and above. In response to EPA’s request, the commenter replied1

that it no longer believes that it would be necessary to incorporate the IMO allowances and 

subsequently withdrew its comments on this issue. Therefore, no further action is needed on this 

issue. 

3.3 Comment: One commenter (37) said that in the preamble to the proposed amendments in the 

third column of page 32616 and the first column of page 32617, the emissions in parentheses are 

shown in grams per kilowatt-hour (g/KW-hr), but they should be in grams per HP-hour (g/HPhr). 

Response: The commenter is correct that these standards were presented incorrectly in the 

preamble to the proposed rule. 

3.4 Comment: Two commenters (37 and 48) expressed support of EPA’s proposal to not require 

aftertreatment-forcing standards for stationary emergency engines with a displacement at or 

above 30 l/cyl. Commenter 48 specifically noted support for the NOx standards not necessitating 

aftertreatment in the proposed rule. According to the commenter (37), these engines are used to 

power emergency generators, especially in critically sensitive installations like nuclear power 

plants. The commenter (37) said that adding aftertreatment to these large engines in order to 

reduce emissions could potentially significantly affect the performance and reliability of the 

emergency engine and aftertreatment is not cost-effective. For these reasons, which the 

commenter (37) said that EPA has used in the past to justify standards for smaller emergency 

 

1

 Email from Joe Suchecki, Engine Manufacturers Association to Melanie King, EPA. Request for Clarification on 

Comment Regarding IMO Allowances. February 22, 2011. 
16

engines, commenter 37 believes that aftertreatment should not be required of stationary 

emergency engines with a displacement at or above 30 l/cyl. The commenter (37) urged EPA to 

finalize the proposed changes on page 32617 of the preamble and in 60.4205 of the proposed 

rule. Also, commenter 37 said that EPA should include the allowances requested in comment 

3.2 (6.3.11 and 6.4.13 of the IMO MEPC 58 Revised ANNEX VI from October 2008) for these 

engines as well. 

Response: No response is needed to the first part of this comment regarding the proposed 

standards for emergency engines with a displacement of 30 l/cyl or more. 

 Regarding the IMO allowances, EPA contacted the commenter for additional 

information. In response to EPA’s request, the commenter replied2

 that it no longer believes that 

it would be necessary to incorporate the IMO allowances and subsequently withdrew its 

comments on this issue. 

3.5 Comment: One commenter (37) indicated that it thought there was an error in the proposed 

rule on page 32623 in 60.4205(d)(2). According to the commenter (37), the NOx standard that 

applies to emergency engines should be applicable past the year 2016 and the commenter (37) 

suggested that EPA take out the text “and before January 1, 2016.”

Response: The commenter is correct and EPA has made this clear in the final rule. 

3.6 Comment: One commenter (37) supports a fuel limit of 1,000 ppm sulfur content for engines 

with a displacement at or above 30 l/cyl. The commenter (37) agrees that it is appropriate to 

 

2

 Id. 
17

align fuel requirements for stationary engines with a displacement at or above 30 l/cyl with those 

that are in the IMO marine engine standards, since the stationary engine emission standards are 

also being aligned with IMO marine engine standards. However, the commenter (37) asked that 

EPA require that this limit become effective immediately and not in 2014, as proposed. The 

commenter (37) claimed that 500 ppm sulfur fuel, which is the sulfur level stationary engines 

with a displacement at or above 30 l/cyl currently must meet for the fuel they use, will become 

very limited and perhaps unavailable after the 15 ppm sulfur fuel requirements take effect in 

October 2010 for most mobile and stationary engines. Engines with large displacement are not 

designed to operate on 15 ppm sulfur fuel, the commenter (37) argued, therefore, appropriate 

fuel for these engines may not be available, or if it is, will be significantly more costly. To 

ensure the availability of appropriate fuel, the commenter (37) asked that EPA allow engines 

with a displacement at or above 30 l/cyl to use 1,000 ppm immediately. 

Response: EPA agrees that it would be appropriate to require that stationary engines with a 

displacement of 30 l/cyl or more limit the sulfur content in the fuel to 1,000 ppm beginning 

earlier than 2014, which is the timeframe that was proposed. However, EPA disagrees with the 

commenter’s logic and that the requirement should become effective immediately. Diesel fuel 

containing 500 ppm sulfur will be the designated off-spec fuel within the diesel stream until 

2014 and should be available at least for locomotives and marine engines until June 1, 2012. 

Therefore, EPA believes it is appropriate to finalize the 1,000 ppm fuel requirement for large 

displacement engines, but require that these engines begin using this fuel on June 1, 2012. EPA 

has made this clear in 60.4207(d) of the final rule. 
18

3.7 Comment: One commenter (37) supports the proposal to require a PM emission standard of 

0.40 g/KW-hr for engines with a displacement at or above 30 l/cyl. According to the commenter 

(37), it is not technically feasible to achieve the limits for PM that are in the current final rule 

without the use of low sulfur fuel, nor is it feasible for emergency engines. 

Response: No response is needed. 

4.0 Operating and Maintenance Requirements 

4.1 Comment: One commenter (37) expressed concern about the proposal that for certified 

engines, owners and operators would be allowed to develop and follow their own operation and 

maintenance (O&M) procedures as an alternative to following the manufacturer’s O&M 

procedures. Commenter 37 recommended that engines that do not follow the manufacturer’s 

O&M procedures be considered as operating in a non-certified manner and subject to initial 

performance testing requirements. The commenter (37) indicated that it is supportive of 

providing additional flexibility, but that in those cases where an owner or operator opts to take an 

alternative O&M approach, which differs from what the manufacturer recommends for the 

engine, the engine manufacturer or certificate holder should no longer be responsible for 

emissions compliance. EPA should make that clarification as to who is responsible for the 

emissions from the engine and if operated differently than recommended by the manufacturer, 

the engine should no longer be classified as a certified engine. 

 The commenter (37) also recommended that in order to avoid disputes regarding who 

would be the responsible party in cases where alternative O&M procedures are being followed, 

that EPA establish a mechanism for owners and operators to identify specific engines or facilities 
19

where such procedures are being used. In the absence of such designation, the regulatory agency 

and the engine manufacturer would not know if the engine is maintained according to the 

manufacturer’s guidelines and conflict could arise if there is a deviation. The commenter (37) 

suggested the owner or operator could apply a permanent label to the engine, if the engine had 

been altered beyond the manufacturer’s recommended O&M procedures. 

 Commenter 37 additionally noted concern over the proposed provision in 60.4211(g) that 

allows owners and operators to adjust engine settings outside of the manufacturer’s 

recommendations. The commenter (37) is of the opinion that such adjustment should only be 

allowed in association with performance testing and the commenter (37) requested that clarifying 

language be included in the final preamble and rule. All engines with a displacement below 30 

l/cyl are under 40 CFR part 60, subpart IIII, required to be certified, and commenter 37 said that 

the certification and emissions compliance are contingent upon the engine being operated within 

certain parameters and settings. Therefore, if these settings are changed, the engine may be out 

of compliance, the commenter (37) said, and such actions significantly affect engine 

performance and emissions levels. Consequently, the commenter (37) recommended that 

changing CI engine settings only be permitted under the following conditions: 

 If the factory settings are changed by the owner or operator, an initial performance test 

should be conducted to confirm that the emission standards are still being met;

 EPA clearly indicates in the final rule that if factory settings are changed, the engine 

manufacturer is no longer responsible for the engine being in compliance with the 

standards and the emissions warranty becomes void at the time of the adjustment and 

after;

 The engine is no longer considered a certified engine;
20

 The owner or operator of the engine alerts the regulatory agency with a notification 

including the engine serial number that it is adjusting the engine settings beyond the 

manufacturer’s recommendations and that acknowledges that the engine is no longer 

considered a certified engine under the stationary (or nonroad, if applicable) regulation, 

and

 The owner or operator applies a permanent label to the engine to indicate that it had been 

altered beyond the manufacturer’s settings.

The commenter (37) urged EPA to make it clear that the additional flexibility provided in the 

final rule by permitting engine settings to be adjusted beyond manufacturer’s recommended 

specifications means that the manufacturers are still required to sell only new certified 

stationary engines and that when owners and operators purchase new engines subject to the 

NSPS, they have to purchase new NSPS-certified engines. The commenter (37) specifically 

said that EPA should make it clear in the final rule that the provision for owners and 

operators to operate a certified engine in a non-certified manner, does not mean that 

manufacturers are permitted to sell new engines that are subject to the NSPS that are noncertified nor does it mean that owners and operators can buy new non-certified NSPScovered engines. 

Response: EPA agrees that the engine manufacturer should not be held responsible once owners 

and operators of a certified engine no longer operate and maintain the engine and control device 

according to the manufacturer’s O&M procedures. This is consistent with the language in 

section 207 of the CAA and 40 CFR 1068.505, regarding mobile source engines, that specifies 

that EPA not require a recall of engines by the manufacturer unless EPA determines that a 
21

substantial number of engines, although properly maintained and used, do not conform to 

emission regulations. EPA thinks that it is clear in the rule language that the owner/operator, not 

the manufacturer, is required to show compliance in such situations, as was specifically laid out 

in 60.4211(g) of the proposed rule. Further, EPA stated in the preamble to the proposed rule that 

engines operated in this manner would be considered non-certified engines and generally subject 

to performance testing (see 75 FR 32615, middle column). 

 Regarding the commenter’s recommendation that engines that do not follow the 

manufacturer’s O&M procedures be considered as operating in a non-certified manner and 

subject to initial performance testing, EPA points to 60.4211(g) of the proposed rule, which 

requires all engines greater than 100 HP to conduct a performance testing. Engines greater than 

500 HP also have to conduct subsequent testing every 8,760 hours of operation or 3 years, 

whichever comes first. Also, owners and operators of engines that are less than 100 HP, where 

the engine and control device are not installed and configured according to the manufacturer’s 

emission-related written instructions or if the emission-related settings are changed in a way that 

is not permitted by the manufacturer, an initial performance test has to be conducted. Again, 

EPA cites to the preamble to the proposed rule where EPA explained that in cases where 

owners/operators take an alternative approach and follow their own O&M procedures versus the 

manufacturer’s procedures, EPA will need more assurance that the engine is meeting the 

emission standards and consequently generally subject these engines to performance testing. 

 Regarding the comment about identifying specific engines or facilities where alternative 

procedures are being used, EPA points out that in 60.4211(g) of the proposed rule it is required 

of owners/operators who follow alternative procedures to keep a maintenance plan and records 

of conducted maintenance. Therefore, documentation of the maintenance conducted would be 
22

available and would indicate if the engine is being maintained according to the manufacturer’s 

guidelines or not. Therefore, EPA does not anticipate that a conflict would arise as to who is the 

responsible party for demonstrating compliance. For this reason, EPA does not believe that 

applying a permanent label to the engine would be necessary. 

 EPA notes that there was an inadvertent error in the proposed rule language at 60.4211(a) 

and (c) where EPA incorrectly referred to subsection 60.4211(f) of the proposed rule. In the 

final rule, EPA correctly references paragraph (g) of 60.4211 in 60.4211(a) and (c). 

 

4.2 Comment: One commenter (48) expressed that it is supportive of gearing O&M 

requirements toward the engine manufacturers, as opposed to the owners and operators. 

However, the commenter (48) said that it is concerned with how owners and operators would 

comply with manufacturer’s O&M procedures related to emissions. These requirements are not 

written as permit enforceable documents and the commenter (48) anticipates several inadvertent 

violations, which in the commenter’s (48) opinion would not necessarily mean an increase in 

emissions. The commenter (48) acknowledged the proposed amendments that incorporate 

additional compliance flexibility in this area; however, the option to use alternative procedures 

requires a compliance test to be conducted on engines above 100 HP. According to the 

commenter (48), compliance testing will be costly and prohibitive for wastewater plants 

effectively eliminating the option to following alternative O&M procedures. The commenter 

(48) feels that EPA should extend the provision that allows engines below 100 HP to simply 

keep a maintenance plan to larger engines as well. 
23

Response: EPA disagrees that a performance test should not be required for this group of 

engines. Assurance is needed to demonstrate that the limits are being met. Also, it is not true 

that all engines below 100 HP are not required to conduct performance testing. If owners and 

operators of stationary CI engines below 100 HP do not install and configure their engine and 

control device according to the manufacturer’s emission-related written instructions or change 

emission-related settings in a way that is not permitted by the manufacturer, an initial 

performance test is required (see proposed 60.4211(g)(1)). The requirement has been retained in 

the final rule. Also, under the SI NSPS, owners and operators meeting standards in section 

60.4233(d) or (e) that have non-certified engines between 25 and 500 HP are subject to testing 

(see 40 CFR 60.4243(b)(2)(ii)). 

5.0 Alaska 

5.1 Comment: One commenter (37) believes there is an oversight in the language in 60.4216 of 

the proposed rule and asked that EPA clarify in the final rule that stationary engines with a 

displacement of greater than 30 l/cyl that are located in Alaska are not required to use 15 ppm 

sulfur fuel, which it believes EPA does not intend requiring. The commenter (37) suggested 

removing the reference to 40 CFR part 69.

Response: EPA agrees with the commenter and recognizes that the language in 60.4216(a) is 

misleading in terms of the fuel required for larger displacement engines. EPA has clarified in the 

final rule that 60.4216(a) is limited to engines with a displacement of less than 30 l/cyl. 
24

5.2 Comment: One commenter (37) expressed support for EPA’s proposal to include different 

requirements for stationary CI engines located in Alaska, i.e., those proposed in 60.4216 of the 

CI NSPS. The commenter (37) also believes that those changes need to be incorporated for 

engines with a displacement 30 l/cyl or greater and suggested that EPA may have inadvertently 

not included those engines when adding those provisions. 

Response: EPA agrees that the provisions in 60.4216(c) of the proposed rule should not be 

limited to stationary CI engines with a displacement below 30 l/cyl, but should also include 

stationary CI engines with a displacement of 30 l/cyl and above. Subsequently, EPA has made 

this clear in the final rule. Also, EPA notes that it has clarified that stationary non-emergency CI 

engines with a displacement of 30 l/cyl and above that are located in areas of Alaska not 

accessible by the Federal Aid Highway System (FAHS) are subject to the PM requirements in 

60.4204(c)(4) that apply to owners and operators of stationary non-emergency CI engines greater 

than or equal to 30 l/cyl. 

5.3 Comment: One commenter (53) asked that EPA reconsider how urban and rural areas of 

Alaska are defined. The commenter (53) acknowledged the definition that is currently in place, 

which defines rural areas as those areas not accessible by the FAHS. This definition has been 

used in Federal regulations for years, but based on recent changes that will require the transition 

to ultra low sulfur diesel (ULSD) for mobile source engines this year in rural areas, the 

commenter (53) requested that EPA evaluate whether the definition remains appropriate. In the 

commenter’s (53) opinion, the current definition does not appropriately consider impacts to 

small rural public utilities in Alaska that may be accessible by FAHS or not. These rural public 
25

utilities must deal with higher costs and have less financial resources than utilities in urban areas, 

plus are operated by staff with limited technical knowledge and training, the commenter (53) 

said. Consequently, drawing a line between sources subject to the rule or not by being accessible 

by FAHS would lead to inequities between small communities in Alaska who mostly all 

experience the same issues, according to commenter 53. The commenter (53) added that a 

source being accessible by FAHS is a reasonable determining factor, but is not an absolute. For 

example, according to the commenter (53), there are sources located along the Alaska Marine 

Highway System and other small remote sources along the highway system that must meet 

different requirements than those off the FAHS, however, their circumstances may not be 

different. Commenter 53 did not have a specific recommendation, but wanted EPA to look at 

possible alternatives for defining urban and rural sources in Alaska that would affect regulated 

stationary engines under the NSPS and NESHAP rules. During this evaluation, the commenter 

(53) asked that EPA take into account engine size and size of communities for instance, in 

determining which engines should not be subject to certain requirements of the rule, and 

indicated that it is willing to discuss this issue further with EPA. 

Response: EPA does not believe that it is appropriate at this time to change how EPA delineates 

between areas of Alaska. The regulations currently in place, which separate areas based on their 

accessibility to the FAHS, were developed under the original rule (71 FR 39154, July 11, 2006) 

and have been in place for regulation of both mobile and stationary engines for several years. 

That rule distinguished accessible areas from non-accessible areas and this criterion is still the 

most reasonable distinguishing factor and EPA therefore believes that it is still appropriate to 

maintain this definition in order to distinguish between stationary engines in Alaska. There are 
26

several places around the country that are small and economically disadvantaged, but only those 

areas of Alaska that are not readily accessible by the highway system are treated differently, in 

particular based on their isolation and the difficulty they have in accessing other areas. EPA also 

notes that this issue has not been brought up before and was not part of the commenter’s request 

letter.3

 Also, all the background information and rationale justifying the recommendations 

provided in the commenter’s request letter to distinguish remote Alaska from the rest of the 

country were based on this split based on accessibility. Many of the requirements in the rule are 

already in place and EPA has not heard of problems in these accessible areas. EPA notes that 

accessibility is interpreted to mean accessibility on a year-round basis, which includes the 

portions of Alaska serviced by the contiguous road system, and portions of the Alaska Marine 

Highway System with regular drive-on, drive-off vehicle service on ferries (e.g., Kodiak, 

Ketchikan, Juneau, Sitka, Haines, Skagway, Petersburg, Wrangell, Cordova). [see 

http://www.dec.state.ak.us/air/anpms/ulsd/ulsdtranplan.htm and 

http://www.dot.state.ak.us/amhs/] The commenter did not provide any specific 

recommendations in terms of how it believes urban and remote areas should be redefined and in 

the absence of clarity on what the boundaries should be, there is no real basis at this time for the 

commenter’s request to make a change to the current distinction. EPA continues to believe that 

the distinction in treatment between engines in Alaska should be based on whether areas are on 

the FAHS system and is therefore not making any changes at this time to this criterion in the 

final rule. 

 

3

 Letter from Alice Edwards, State of Alaska to Jaime Pagán, EPA. Alaska Comments on NSPS for Stationary 

Diesel Engines. October 31, 2008. 
27

5.4 Comment: One commenter (53) expressed concern over the proposed requirements for small 

remote power plants in Alaska that would necessitate aftertreatment in order to meet the PM 

limits. The commenter (53) pointed out that EPA recognized that selective catalytic reduction 

(SCR) is not justified in rural Alaska. The commenter’s (53) concern regarding aftertreatment 

for PM is based on the majority of small rural power plans being un-staffed and the technical 

capability of staff is minimal and includes only basic maintenance tasks, including maintaining 

the oil, filter, belts and hoses. The commenter (53) said that engines that are equipped with 

aftertreatment like diesel particulate filters (DPF) and oxidation catalysts have automatic safety 

devices installed that will derate the engine in the event that the backpressure or temperature go 

beyond prescribed limits. Commenter 53 made the argument that should a prime power 

generator derate at a plant that was not staffed, the engine would not maintain frequency and 

would trip off line. The engine would shutdown and power would be interrupted or unavailable 

to the community, the commenter (53) said, and should this happen during extreme temperatures, 

the life, health and safety of a community are at stake. Defeat devices are not permitted under 

EPA’s regulations for certified engines so the consequence would be that the only way an engine 

could be restarted would be for a technician to fly to the plant and address the issue, the 

commenter (53) said. Considering transportation limitations in rural Alaska, especially during 

extreme cold weather at winter time, it could take several days for the technician to arrive at the 

site, commenter 53 noted. Because of the following reasons, the commenter (53) recommended 

that aftertreatment for reducing PM emissions not be required for small unmanned rural Alaska 

power plants: 
28

 Power plant PM emissions in rural Alaska are substantially less than what EPA used for 

baseline emissions in 1990 calculated from AP-42 information, which means the air is 

already cleaner than EPA’s estimation; 

 The density of emissions in a rural community is normally lower than an urban area. 

Since the only diesel engine operating in a rural community is the one at the power plant, 

the magnitude of diesel PM emissions in a rural area is different than an urban one; 

 Not requiring PM traps removes issues with high sulfur fuel (from used oil blending) 

contaminating aftertreatment; 

 Reliable electric power is vital to life, health and safety; and 

 The cost over the entire life span of PM aftertreatment in rural Alaska is two to three 

times higher than EPA estimated for urban areas in the U.S. EPA used this rationale to 

exclude stationary engines in rural Alaska from numerical emission standards under the 

NESHAP and from meeting emission limits based on the use of SCR under the NSPS. 

Response: EPA disagrees with the commenter that PM limits that necessitate the use of 

aftertreatment like DPF should not be required at all for stationary CI engines located in remote 

areas of Alaska. The need for PM control was in the commenter’s original request to EPA 

noting that PM is the most significant pollutant of concern in remote areas of Alaska. Stationary 

CI engines are often in very close proximity to the towns and the diesel PM emissions, which are 

highly toxic, can fall on the towns. Substantial health impacts are associated with diesel PM 

emissions and EPA does not believe it is appropriate to reduce the stringency of PM 
29

requirements in remote Alaska. EPA’s Diesel Health Assessment Document4

 (Diesel HAD) 

classified exposure to diesel exhaust as “likely to be carcinogenic to humans by inhalation” at 

environmental levels of exposure. Other agencies at the international, federal and state level have 

come to similar conclusions.5

 The Diesel HAD concludes “that acute exposure to DE [diesel 

exhaust] has been associated with irritation of the eye, nose, and throat, respiratory symptoms 

(cough and phlegm), and neurophysiological symptoms such as headache, lightheadedness, 

nausea, vomiting, and numbness or tingling of the extremities.”6 There is also evidence of 

immunologic effects such as the exacerbation of allergenic responses to known allergens and 

asthma-like symptoms. 

 The commenter has not provided any evidence to support the claim that PM traps using 

low sulfur fuel tend to cause shutdowns. These devices are going on unmanned units in 

numerous places, but there should be people in the towns who are in much closer proximity to 

the engines than the engines in remote locations across the United States. Regarding the 

concerns raised by the State of Alaska regarding the feasibility and cost of installing and 

operating DPF in remote villages, EPA is providing additional time in the final rule before new 

stationary engines in remote areas of Alaska are required to meet PM standards that would 

require DPF. The final rule requires new engines in remote areas of Alaska to meet the more 

stringent PM standards and use ULSD beginning with 2014 model year engines. The use of DPF 

for new nonroad and stationary diesel engines in the United States will be phased in from 2011 

to 2015. Waiting until there is more widespread experience with operating and maintaining DPF 

 

4

 Health Assessment Document for Diesel Engine Exhaust,’’ U.S. Environmental Protection Agency, 600/8–

90/057F, http://www.epa.gov/ttn/atw/ dieselfinal.pdf, May 2002. 5

 A number of other agencies (National Institute for Occupational Safety and Health, the International Agency for 

Research on Cancer, the World Health Organization, California EPA, and the U.S. Department of Health and 

Human Services) have made similar classifications regarding the diesel exhaust lung cancer hazard.

6

 “Health Assessment Document for Diesel Engine Exhaust,” U.S. Environmental Protection Agency, 600/8–

90/057F, http://www.epa.gov/ttn/ atw/dieselfinal.pdf, May 2002, p. 9–9.
30

would allow time for Alaska's concerns regarding the feasibility of maintaining DPF on engines 

in remote areas to be addressed. The type of engines most often used to power the remote 

villages were required by the original final NSPS to meet PM standards based on the use of DPF 

beginning with the 2011 or 2012 model year, depending on the engine size. Providing a delay 

until the 2014 model year for engines located in remote Alaskan villages would provide State 

with 2 to 3 years to gain experience with the operation of the controls and develop the equipment 

infrastructure needed to properly operate and maintain the DPF. In response to this comment, 

EPA consulted with vendors of DPF, who indicated that the installation and maintenance costs 

for the systems are not as high as the estimates provided by the State of Alaska.7

 EPA 

recognizes that the blending of used oil into diesel fuel is a concern for engines equipped with 

DPF; however, EPA believes that given the restrictions in the rule for used oil blending (no more 

than 1.75 percent of total fuel and no more than 200 ppm sulfur in the oil), the increase in sulfur 

caused by the blending should not be a significant concern for the operation of DPF-equipped 

engines. 

5.5 Comment: One commenter (55) said that it supports the proposed revisions to 60.4216 of 40 

CFR part 60, subpart IIII, affecting engines in Alaska. 

Response: No response is needed. 

5.6 Comment: One commenter (53) supported allowing used oil blending under the CI NSPS 

and reiterated its concerns from 2008. The commenter (53) argued that used oil blending is 

 

7

 See memorandum titled “Summary of Calls with Vendors of Diesel Particulate Filters (DPF)” in docket EPA-HQOAR-2010-0295. 
31

important for rural Alaska facilities. According to the commenter (53), the used oil that is used 

for blending with diesel fuel does not come from outside sources, but comes from within the 

facility from the operation of the facility’s own engines. Being permitted to blend used oil for 

burning in the facility’s own engine is important and decreases risks related to disposal and spills 

in areas that have limited resources available to deal with such costs, the commenter (53) said. 

Blending also provides additional energy from an available resource and according to the 

commenter (53), a significant environmental concern in rural Alaska is the improper disposal of 

used oil. In most rural Alaska communities, there are no permitted used oil disposal facilities 

and the cost of exporting used oil is burdensome and can be the same price or more than 

purchasing new oil, commenter 53 noted. According to the commenter (53), the Alaska Energy 

Authority has developed a system of used oil blending that is cost-effective, reliable, 

environmentally appropriate, and that is used by several power plants in rural Alaska. The 

commenter (53) recommended that used fuel blending be allowed in the rule at a maximum 

blend level of 1.75 percent; a level that the commenter (53) has determined will keep fuel within 

the American Society for Testing and Materials specifications. 

Response: EPA acknowledges the commenter’s concern on used oil blending, but notes that 

there is nothing in the rule that prevents the use of used oil unless it has a sulfur level above 15 

ppm. Nonetheless, EPA believes it is appropriate to provide an additional provision to allow a 

very limited percentage of used oil (no more than 1.75 percent) as the commenter proposed. 

EPA is also requiring that the motor oil used for blending have no more than 200 ppm sulfur. 

Used oil blending, under this provision and in general, is permitted if the used oil is “on-spec,” 

i.e., it meets the on-specification levels and properties of 40 CFR 279.11. If the used oil does not 
32

meet these on-spec criteria the used oil would be considered a solid waste and subject to 

requirements under CAA section 129 for solid waste incineration units. The requirements for 

these units are in 40 CFR part 60, subpart CCCC. 

6.0 Temporary, Replacement, and Marine Engines 

6.1 Comment: Three commenters (37, 54 and 55) agree with EPA’s treatment of temporary 

engines as not having to meet requirements beyond those for nonroad engines, and the proposed 

language in 60.4200(e) of 40 CFR part 60, subpart IIII, regarding temporary replacement 

engines. Commenter 55 suggested making the same change in 40 CFR part 60, subpart JJJJ. 

 Three commenters (37, 54 and 55) indicated that while they are supportive of the 

proposed language in 60.4200(e) of 40 CFR part 60, subpart IIII, regarding temporary 

replacement engines they do not entirely agree with EPA’s rationale provided in the preamble to 

the proposed rule at 75 FR 32616 and another commenter (31) also does not agree with EPA’s 

rationale. Commenter 54 said the language in the preamble could lead to confusion. 

Specifically, commenter 54 indicated that the preamble seems to incorrectly assume that any 

replacement engine is a stationary engine. Similarly, commenter 37 indicated that the language 

in the preamble to the proposed rule is confusing and inconsistent. Commenter 31 and 47 

expressed similar concerns regarding EPA’s interpretation. One commenter (37) recommended 

that EPA should clarify the language, in particular EPA’s second paragraph. Equally, 

commenters 31 and 49 indicated that some of the supporting rationale language provided in the 

preamble to the proposed rule is overly broad and with the provision in 60.4200(e) of the 

proposed CI NSPS could lead to mobile source engines being inadvertently treated as stationary 
33

sources. Commenter 31 asked that EPA remove 60.4200(e) from the CI NSPS or, as an 

alternative, modify what the commenter (31) believes to be overly broad language in the 

preamble, including “portable engines that replace existing stationary engines on a temporary 

basis are considered stationary engines” and add clarification to the language in the preamble on 

this issue. 

 Two commenters (31 and 49) provided an example of a situation where a portable 

generator is used temporarily when the primary generator is not in service. Three commenters 

(31, 49 and 54) said that EPA has made it clear that a portable generator is (absent the 

clarifications under the definition of a nonroad engine) a mobile source, not a stationary source 

and some commenters quoted the following language from the final 2004 nonroad rule (69 FR 

38979) where EPA stated: 

 “The final standards are based on our evaluation of the differing technical issues 

presented by the two primary kinds of equipment in this category, mobile power generation 

equipment (generator sets) and mobile machinery.” 

 The commenters (31, 49 and 54) recognize that the definition of a nonroad engines in 40 

CFR 1068.30 places restrictions on using portable equipment for stationary purposes and cited 

40 CFR 1068.30(2)(iii) of the definition of a nonroad engine: 

 “(2) An internal combustion engine is not a nonroad engine if: 

 ... 

 (iii) the engine otherwise included in paragraph (1)(iii) of this definition remains or will 

remain at a location for more than 12 consecutive months or a shorter period of time for an 

engine located at a seasonal source. A location is any single site at a building, structure, facility, 

or installation. Any engine (or engines) that replaces an engine at a location and that is intended 
34

to perform the same or similar function as the engine replaced will be included in calculating the 

consecutive time period.” 

 Commenters 49 and 54 indicated that they believe the consecutive period language is 

intended to capture replacement of portable equipment with portable equipment, not the 

replacement of stationary equipment. The commenters (49 and 54) argued that the reference to 

“engine” in the underlined text in the above quoted language refers to a “nonroad” engine. 

Further, the commenters (49 and 54) cited EPA statements from the June 17, 1994 preamble to 

40 CFR part 89, which said: 

 “A portable generator engine which functions as a permanent back-up generator and 

which is replaced by a different engine (or engines) that performs the same function would be an 

example of engines covered by (2)(iii). In such a case, the cumulative "residence” of time of both 

generators, including the time between removal of the original engine and installation of the 

replacement, would he counted toward the consecutive residence time period.” 

 The commenters’ (31, 49 and 54) point was that if the consecutive residence time 

calculation includes a permitted, non-portable stationary engine, as opposed to a portable engine 

operating as a permanent engine, originally contemplated as part of the existing stationary source 

older than 1 year, the commenters (49 and 54) said that the time will always be more than 12 

months and any portable unit that replaces a permanent stationary unit even temporarily, will be 

considered a stationary engine. In the commenter’s (49) opinion this in inaccurate and there is 

no meaning here. 

 Commenter 49 also presented the example where an existing emergency generator is 

being replaced by another emergency generator, but that during construction and installation, the 

facility might bring in a portable generator in the meantime during if there is a time period where 
35

neither the existing emergency generator nor the replacement emergency generator is operating. 

The portable generator may be on a trailer at the facility, but is not at the exact same location as 

the existing emergency generator. The commenter (49) noted that the portable generator sitting 

on a trailer is clearly a nonroad engine because it is not replacing the existing unit and is not at 

the same location and the commenter (49) agrees that this portable unit should be treated 

identically to an engine brought to a site for less than 1 year for general maintenance or 

construction. Classifying the portable unit in this manner is critical, the commenter (49) said 

because otherwise, if the engine is considered a stationary unit, it would be subjected to 

Prevention of Significant Deterioration (PSD) and minor stationary source construction permit 

requirements. According to the commenter (49), portable generators frequently exceed 

permitting thresholds on a potential to emit (PTE) basis, however the actual emissions from the 

unit is minimal to none. The commenter (49) added that portable units do not quality as 

replacement units as defined in 40 CFR 51.166(b)(32) and consequently would be subject to the 

PTE test. The commenter (49) expressed that it does not agree with EPA treating any portable 

equipment that replaces a stationary unit to PSD and minor stationary source construction 

permitting requirements, even if the unit is temporarily at the site for less than 12 months. The 

commenter (49) recommended that EPA require stationary source permitting only if a portable 

engine stays or will stay at the stationary location for more than 12 consecutive months. The 

commenter (49) also asked that EPA either remove 60.4200(e) or revise the preamble discussion 

on this issue, particularly the statement: “Portable engines that replace existing stationary 

engines on a temporary basis are considered stationary engines” and clarify EPA’s intentions. 

 Commenter 55 said that it believes that a nonroad engine is a nonroad engine until it no 

longer meets the definition in 40 CFR 1068.30. Commenter 55 indicated that it does not believe 
36

that a nonroad engine is considered a nonroad engine and a stationary engine, as discussed in the 

preamble to the proposed amendments. 

 Commenter 47 asked that EPA clarify language on page 32616 of the proposed preamble 

that discusses portable engines, specifically the language in the third paragraph under the section 

C. The commenter (47) highlighted the language in the first three sentences of that paragraph to 

be most troublesome. The commenter (47) believes that this language as written is confusing 

when it comes to the status of portable engines that temporarily replace stationary engines and 

argued that this could actually cause temporary portable engines to be restricted in some 

jurisdictions. The commenter (47) wanted EPA to specifically clarify the language on this issue 

and that the same approach as taken when the CI NSPS was finalized in 2006 remains in effect. 

The commenter (47) indicated that it disagrees that portable engines that replace stationary 

engines temporarily should be treated as stationary engines, which the commenter (47) said is 

inconsistent with EPA’s prior approach. Again, treating portable engines as such could lead to 

portable engines not be allowed to be used as temporary replacement units, the commenter (47) 

said, who stressed the importance and need for portable engines, highlighting the ability to 

quickly move a portable engine to replace a stationary engine that has experienced a malfunction 

or is in need of repairs that were not anticipated. The commenter (47) emphasized the 

significance of portable engines, which are critical to support facility operations short term while 

the main, stationary engine is temporarily out of service. According to the commenter (47), there 

are several State and local agencies who have categorical pre-construction permitting exemptions 

for nonroad or portable engines, if the engine meets the definition in 40 CFR 1068.30 of a 

nonroad engine (excluding paragraph (2)(ii) of that definition), e.g., Massachusetts. The 

commenter (47) argued that if EPA considers temporary replacement engines stationary sources 
37

and subject to requirements under 40 CFR part 60, subpart IIII, State and local authorities may 

require pre-construction approval based on the engine being subject to NSPS (e.g., Colorado and 

Oklahoma). Also, the commenter (47) said that if such engines are considered stationary and 

regulated as such, it might be necessary for facilities to acquire a State construction permit prior 

to operation. The permit approval process could take several months, the commenter (47) said, 

which clearly would preclude the ability to use temporary, emergency replacement units. The 

commenter (47) does not believe that EPA needs to treat portable engines that temporarily 

replace stationary engines as stationary engines. The commenter (47) recommended that EPA at 

a minimum clarify that portable engines that replace stationary engines on a temporary basis that 

are undergoing bona fide maintenance and repair would not be considered stationary engines. In 

situations where the maintenance and repair cannot be documented, the portable engine should 

be treated as a stationary engine and its emissions should be included in emission calculations, 

the commenter (47) asserted. 

Response: EPA notes that this rulemaking does not change the definition of nonroad engine or 

stationary engine and is merely reiterating its views on these longstanding definitions. EPA 

disagrees with the commenters’ statements that portable engines that replace existing stationary 

engines on a temporary basis should not be considered stationary engines. The definition of 

nonroad engine explicitly states that “Any engine (or engines) that replaces an engine at a 

location and that is intended to perform the same or similar function as the engine replaced will 

be included in calculating the consecutive time period [for determining whether engines are 

nonroad or stationary].” See, e.g. 40 CFR 89.2 and 1068.30. The import of this language is that 

all engines that are at a location performing the same or similar function would be considered 
38

stationary engines if the combined time period is greater than 1 year for a non-seasonal source. 

This is clear in the preamble to the rule that promulgated this definition. 

 The revised nonroad engine definition also includes a provision that if an engine is 

replaced by another engine within the 12 month period, the replacement engine should be 

considered in calculating the consecutive time period. This provision is designed to ensure that 

where an internal combustion engine is necessary for the operation of a stationary facility, the 

replacement of one particular engine with another would not prevent the engines from being 

included as part of the stationary facility (59 FR pages 31305, 31311). 

 Thus, all engines that perform the same or similar function at a location would be 

considered stationary if their combined residence time is greater than 1 year. 

 This is not inconsistent with the language in the preamble to the 2004 nonroad engine 

rule. Certainly mobile generators sets, i.e., those that are not defined to be stationary, would be 

covered by that rule. This would include many portable engines, but not those excluded from the 

definition of nonroad engine in paragraph (2)(iii) of that definition. Indeed, the reason why the 

stationary CI engine standards were coordinated with the nonroad engine regulations is because 

many of the same types of engines would be used in both nonroad and stationary applications. 

EPA notes that the language in the 2006 CI NSPS Response to Comment document is confusing 

in that it initially seems to be counter to the language regarding replacement engines in 

paragraph (2)(iii) of the nonroad engine definition, but it then caveats its initial statement by 

referencing that paragraph. To the extent the language in the 2006 document is inconsistent with 

this Response to Comment document, the language in the preamble to the initial nonroad rule, 

and the language in the regulatory text, it should not be relied upon. 
39

 The commenters’ view that the language in the definition refers only to replacement of 

one portable engine with another is belied by the language in the definition (“Any engine (or 

engines) that replaces an engine at a location and that is intended to perform the same or similar 

function as the engine replaced will be included,” emphasis added) and in the preamble language 

quoted above. The distinction the commenter attempts to make is also illogical in that the 

distinction it makes between the engines being replaced is not based on the criteria (e.g., 

residence time or the stationary nature of the replaced engine) found in the definition. In 

addition, the suggestion that word “engine” in the definition of “nonroad engine” should be 

interpreted to mean only nonroad engines is contrary to the plain language of the definition and 

is also illogical, since the point of the definition is to define what engines are nonroad engines, as 

opposed to other types of engines, and restricting the word “engine” to nonroad engine would 

defeat that purpose and would also involve circular logic. Nor does this interpretation mean that 

the residence time requirement will always result in engines being considered stationary engines, 

as in many instances (e.g., engines brought in to perform a particular service like construction or 

maintenance or drilling) the residence time language defines whether the engine is stationary or 

nonroad. 

 However, EPA agrees with the views of commenters that note the replacement engine 

must be at the same location as the engine it is replacing to be included in the same residence 

time, which may in many cases address the concerns of the commenters. EPA has revised the 

language of the preamble to adhere more closely to the language in the regulatory definition of 

nonroad engine. 

 Commenter 49 does not believe emissions from these engines should be included in the 

emissions for the stationary source, but the entire purpose of defining these engines as stationary 
40

engines is to prevent sources from excluding these emissions (as well as the emissions of the 

engine they replace) in calculating emissions from the source, despite the fact that they clearly 

are tied to the permanent emissions profile of the source. The commenter does not explain why 

these engines would have potential-to-emit any greater than the engines they replace, unless they 

actually do emit more, in which case such emissions should be accounted for. It is not clear if 

the commenter is stating that operators would be required to account for the emissions of both 

engines at the same time even if one is truly replacing the other temporarily and they never 

operate at the same time. That issue is beyond the scope of the NSPS. In any case the provisions 

of both this definition and those in 40 CFR part 51 have been in place for many years and were 

not changed in this rule. 

6.2 Comment: Several commenters (37, 54, and 55) provided their opinion and 

recommendations on how to treat stationary engines used in marine offshore settings. One 

commenter (54) said that marine engines should not be subject to land-based standards and 

indicated support for revisions to allow the use of marine based standards as opposed to NSPS 

for offshore platform installations. The commenter (54) indicated that these engines are 

normally nonroad engines that are subject to marine engine standards. The engines remain a 

nonroad engine until it no longer meets the criteria of the nonroad engine definition in 1068.30 

and becomes instead a stationary engine, as defined in 40 CFR 60.4219 (CI NSPS) and 40 CFR 

60.4248 (SI NSPS), according to the commenter (54). Further, the commenter (54) said that 

these criteria should apply if an engine replaces or acts as a stationary engine, or is on the 

platform for less than 1 year for general maintenance or construction activities. The commenter 

(54) said that if the marine engine is used in a stationary manner, the commenter (54) is 
41

supportive of language being added to indicate that stationary engines in marine offshore settings 

may comply with applicable marine engine standards as opposed to the land-based standards. 

The commenter (54) asked that this language be added to both 40 CFR part 60, subparts IIII and 

JJJJ. 

 Two commenters (37 and 55) responded to EPA’s request for comment on the need for 

stationary engines in marine offshore settings to use engines meeting the marine engine 

standards, rather than land-based engine standards. Commenter 55 said that it supports using 

marine-based standards for offshore platform installations. The commenter (55) said that those 

engines are nonroad engines subject to marine-based standards unless the engines stay in one 

location on the platform for more than 12 months. The commenter (55) believes that these 

criteria should apply if the engine replaces a stationary engine or is at the platform for less than 1 

year for general maintenance or construction activities. In the event that the marine nonroad 

engine becomes a stationary engine, the addition of language in 60.4200(e) or another section of 

40 CFR part 60, subpart IIII indicating stationary engines in marine offshore settings may 

comply with applicable marine engine standards rather than the land-based engine standards in 

40 CFR part 60, subpart IIII. For consistency, this approach should also be applied to the SI 

NSPS (40 CFR part 60, subpart JJJJ) and the NESHAP (40 CFR part 63, subpart ZZZZ). 

Commenter 37 said that it supports the use of either nonroad or marine certified engines 

for stationary engines on offshore platforms because it provides flexibility and advantages where 

space and weight limitations could lead to significant considerations. Furthermore, in the 

commenter’s (37) opinion, the difference between emissions from marine and nonroad engines 

should be of minimal concern because of the remote location of offshore platforms. 
42

Response: EPA requested comment on the need for stationary engines in marine offshore 

settings to use engines meeting the marine engine standards, rather than land-based engine 

standards. Based on comments received on this issue, EPA agrees that it would be appropriate to 

allow stationary engines used in marine offshore settings to meet marine engine standards. EPA 

understands that engines used in these settings are generally certified to marine standards and 

that it may not be possible to know how an engine will be used throughout its life when it is first 

used. EPA does not see a need to require engines utilized in the same marine offshore setting to 

be certified to different standards based solely on the time an engine remains in one offshore 

location. It therefore is appropriate to require engines used in both mobile and stationary marine 

offshore applications to be able to meet the same standard. 

7.0 Digester Gas Engines 

7.1 Comment: One commenter (48) requested relief for stationary engines fueled by digester gas 

claiming that the emission standards applicable to these engines are hard to comply with. 

Moreover, the digester gas that is used in engines to create power is generated from wastewater 

treatment and contains methane, a potent greenhouse gas, the commenter (48) said. This gas can 

be used to power engines while reducing utility reliance on other fuel sources and decreasing 

greenhouse gas emissions, the commenter (48) argued and believes that utilities should be 

encouraged to operate engines on digester gas, as opposed to going with the option of purchasing 

power and wasting a valuable fuel source by flaring the digester gas created from the wastewater 

treatment process. Therefore, the commenter (48) asked that stationary engines that utilize 

digester gas fuel be exempt from the NSPS. 
43

Response: EPA contacted the commenter for further information regarding this comment and 

confirmed with the commenter that the comment pertains to both 40 CFR part 60, subpart IIII 

and subpart JJJJ. The commenter indicated that its members operate digester gas fueled engines 

that are both CI and SI engines, and according to the commenter, these engines would have 

difficulties meeting the NSPS emissions standards. What the commenter is requesting related to 

exempting digester gas engines that are SI engines is not in the scope of this rulemaking. This 

rulemaking only makes substantive changes to 40 CFR part 60, subpart IIII (CI NSPS) and minor 

changes to 40 CFR part 60, subpart JJJJ (SI NSPS) more for consistency purposes. EPA is not 

exploring issues that are unique to the SI NSPS at this time. The commenter did not provide any 

information to support the claim that digester gas engines cannot meet the applicable emission 

standards. In addition, 60.4217 in 40 CFR subpart IIII allows owners/operators of engines using 

special fuels to petition the Administrator for alternative emission standards for the engines. 

8.0 Test Methods 

8.1 Comment: One commenter (37) said that the test method for stationary engines with a 

displacement at or above 30 l/cyl needs to be changed from Method 5 to Method 5B or Method 

17. The commenter (37) indicated that it has previously submitted a letter to EPA describing its 

concerns with using Method 5 for these engines. The commenter (37) reiterated its position that 

Method 5 is inappropriate and that EPA should allow alternative methods for measuring PM. 

The main reason the commenter (37) believes Method 5 is not suitable is because it requires the 

use of glass fiber filters maintained at 120 degrees Celsius (°C). The method also requires that in 
44

sources that have sulfur dioxide (SO2) or sulfur trioxide (SO3) that the filter material be 

unreactive to these pollutants and International Organization for Standardization (ISO) method 

9096 2003 does not recommend glass fiber filter use where this reaction occurs. The commenter 

(37) went on to say that the temperature required by Method 5 is generally much lower than 

normal exhaust temperatures from large displacement engines. This necessitates cooling of the 

exhaust gas in order to use Method 5, the commenter (37) said, which would lead to the 

formation of additional condensation particles that would affect the sampling results. The 

commenter (37) argued that the method would not yield reproducible results and recommended 

that due to inconsistencies, EPA should allow alternative methods. Commenter 37 

recommended that EPA raise the PM sampling temperature in Method 5 to a minimum of 160°C, 

which essentially means changing Method 5 to Method 5B, and also allow stationary engines to 

use Method 17 as an alternative. 

Response: EPA disagrees with the comment that EPA Method 5 does not provide accurate and 

precise measurements of PM. The statements in EPA Method 5 and ISO 9096 2003 regarding 

the selection of filtration media that are unreactive to SO3 are intended to ensure that the proper 

filter media are used. When acceptable filter media are selected, including glass fiber filters that 

are unreactive to SO2 or SO3, EPA Method 5 has been shown to provide reproducible results 

irrespective of the filtration temperature chosen. 

 EPA also disagrees that EPA Method 5 cannot achieve a filtration temperature of 120°C 

(250°F) since there are no procedures for cooling the sample gas from the stack temperature to 

the required filtration temperature. EPA Method 5 is silent on the method for cooling the sample 

gas, as this is left to the discretion of the source test individual. The method employed depends 
45

upon the stack gas temperature, the required filtration temperature, and the equipment available 

to the individual test contractor. In most situations, no special procedures are required since 

sufficient cooling is achieved by normal air exposure of the probe and filter holder. Where 

filtration temperature is likely to exceed the method specified temperature, contractors have used 

specially constructed air cooled or water cooled probes to achieve the proper temperature. 

 Regarding the use of Method 5B or Method 17 as an alternative to Method 5, the mass of 

filterable PM emissions perhaps more than any other pollutant is defined by the test method and 

the associated sampling conditions. Filter temperature is the primary driver of differences 

between results from different methods along with the relative concentrations of constituents of 

the stack gas that condense at or above the filter temperature. For fossil fuel combustion 

products, there are ash particles that will be solid and collected at any practical sampling 

temperature. Any of the three methods will measure the same mass of ash-derived particle 

emissions. The complexity comes because of some acid gases also in the stack exhaust, 

particularly sulfuric acid from oxidation of the sulfur in the fuel. These acid gases begin to 

condense at temperatures below 160°C more or less in proportion to the acid gas concentration. 

That means that a method such as Method 5B with a filter temperature controlled to 160°C will 

collect less mass of these acid gas particles than will a Method 5 with a filter temperature 

controlled to 120°C. Method 17 provides for inserting the filter in the stack presenting an even 

more variable measurement. The practical stack gas upper temperature limit for Method 17 is 

about 160°C but the method can be used at much lower temperatures (until water droplets form 

in the stack). EPA cannot predict how results collected at different filter temperatures will 

compare for a particular source or between sources except that particulate samples collected at 

lower filter temperatures will produce higher mass emissions than samples collected with higher 
46

filter temperatures. EPA does not agree that it would be appropriate to allow the use of Method 

5B or Method 17 as an alternative to Method 5 due to this difference in results, and lack of 

predictability regarding how particulate levels will change at different temperatures. 

8.2 Comment: One commenter (37) noted that the June 13, 2007, final NSPS for Electric Utility 

Steam Generating Units and Industrial-Commercial-Institutional Steam Generating Units 

specified the use of EPA Method 5 with a sample temperature of 160°C, and also allowed EPA 

Method 17 for boilers. 

Response: The commenter is correct that NSPS for Electric Utility Steam Generating Units and 

Industrial-Commercial-Institutional Steam Generating Units allows the use of EPA Method 5 at 

160°C (320°F). EPA Method 5 at 160°C is used for compliance since all test data used as the 

basis of the numerical emissions limit in that NSPS were collected at 160°C. 

8.3 Comment: One commenter (27) said that it agrees with EPA’s earlier response to previous 

comments regarding Method 5. The commenter (27) indicated that material deposited in the 

probe as sample gas cools from stack temperature to 248 °F required by Method 5 will be 

recovered and weighed under the Method 5 normal procedures. Despite the commenter (27) 

noting this, it is concerned about another aspects of the method, i.e., PM emissions may still be 

in the vapor phase at temperatures of 248°F and the commenter (27) recommends that EPA 

lower the probe and filter temperature to more accurately represent actual PM emissions. 

Alternatively, commenter 27 suggested that EPA require the use of the new “back half,” Other 

Test Method (OTM) 28 for measure PM emissions. Further, the commenter (27) noted that if 
47

emissions are found to be very low, Method 5I would be a more appropriate alternative than 

Method 5 because it ensures a lower detection limit for PM collected from low concentration 

sources. The commenter (27) added that the above temperature considerations apply to Method 

5I also. In the commenter’s (27) opinion, if in-stack sampling methods are chosen, i.e., Method 

17, Method 201A or OTM 27, OTM 28 should also be specified to assure that all PM that is 

solid or aerosol at ambient temperature will be quantified. 

Response: EPA Method 5 does exclude PM which are vaporous at elevated temperatures, but 

which condense to form fine PM at ambient temperatures. The addition of the recently 

promulgated revised Method 202 (which replaced both the 1990 version of Method 202 and 

OTM 28) to Method 5 quantifies this additional PM. The maximum filtration temperature for 

Method 202 is 30°C (85°F) and would be expected to retain a greater mass that any of the 

previously mentioned test methods. While each of these test methods will quantify a different 

mass of PM, when performed consistently within their respective specifications, each method 

provides for precise mass emissions measurements. 

9.0 Definitions 

9.1 Reconstruction 

9.1.1 Comment: Several commenters (26, 32, 37, 39, 40, 43, 46, 50, 53, and 55) are concerned 

with the proposed definition of reconstruction. According to Commenter 55, this and other terms 

(date of manufacture and installed) have been included by EPA in order to redesignate stationary 

engines currently not subject to the rule to become subject to NSPS after conducting routine 
48

maintenance, repair, rework, and overhaul. Several commenters (43, 46, 50, and 55) stated that 

EPA has not provided sufficient rationale for adding this new definition and the term is 

significantly different from other NSPS definitions and applicability determinations regarding 

reconstruction. One commenter (55) also stated that the definition is inconsistent with the 

definition used in the NESHAP. Two commenters (43 and 55) said that the proposed revisions 

add problems and commenter 55 is of the opinion that the rulemaking adds burden and 

implementation issues to the regulated community beyond currently unresolved issues, which the 

commenter (55) said it has previously brought to EPA’s attention.8 

One commenter (50) said that if the definition is finalized as proposed the outcome for 

the commenter’s (50) industry is that most existing natural gas engines will trigger 

reconstruction at every overhaul. Subsequently, nearly all these engines would transition from 

an existing engine to being subject to 40 CFR part 60, subpart JJJJ, in an infeasible time frame. 

As discussed in comment 9.2.1, the commenter (50) further indicated that this would also result 

in (due to the removal of the crankshaft language) these engines having to meet new engine 

standards; levels that these older engines were not designed to achieve and some would be 

incapable of meeting. The commenter (50) asserted that the proposal will have substantial cost 

impacts that necessitate a cost-benefit analysis to support the justification for basically instituting 

a new rulemaking for existing engines. 

Two commenters (46 and 50) said that the proposed definition excludes the cost of 

fundamental components from the fixed capital costs, such as the engineering costs, construction 

and site installation and startup costs, and the costs associated with auxiliary components that 

service or that are critical to the engine’s operation. Commenter 55 made similar claims. One 

 

8

 Letter from Stephanie R. Meadows, Senior Policy Advisor, American Petroleum Institute, to Michael Horowitz, 

Office of General Counsel, U.S. Environmental Protection Agency. March 10, 2010. 
49

commenter (50) indicated that there are several examples of precedent that demonstrates the 

components that should be included in fixed capital costs. The commenter (50) cited to several 

EPA applicability determinations (e.g., Control #9800085 dated 5/11/98 and Control #0200048 

dated 9/3/99), pointed out the language in EPA’s December 16, 1975 preamble to the NSPS, and 

other applicability determinations EPA has conducted, which all demonstrate that key 

components necessary for engine operation should be included in the fixed capital cost 

calculation. Again, the commenter (50) said that it believes EPA has failed completely in 

providing the public justification for changing the definition, which EPA is legally obligated to 

do. 

Commenter 43 asserted that it strongly objects any exclusion of components necessary 

for engine operation in the reconstruction determination and stressed that such components like 

the cooling system, should be included even though it is not connected to the engine like it is for 

smaller engines. 

 Two commenters (43 and 55) requested that EPA use the definition of reconstruction that 

is currently in 40 CFR 60.15(b) in the final rules and asked that the proposed new definition of 

“reconstruct” in 60.4219 and 60.4248 not be included in the final rules. According to commenter 

55, reconstruction under 40 CFR 60.15(b) differs substantively from the proposed definition 

under 60.4219 and 60.4248, including unjustifiably designating many rebuilt engines, that would 

have remained “existing”, as “reconstructed” (and therefore subject to new emission limits). 

Likewise, commenter 46 requested that EPA maintain the definitions in 40 CFR 60.15(b) and 40 

CFR 60.15(c), for reconstruction and fixed capital cost, respectively, in the final SI NSPS. The 

costs of the compressor and any driven equipment and other components not needed to operate 

the engine should be excluded from the term fixed capital cost, the commenter (46) said. 
50

Similarly, commenter 50 asked that EPA retain the reconstruction definition from 40 CFR 60.15, 

but limit the applicability to stationary SI engines as follows in 60.4248: 

“Reconstruct means to replace or refurbish components of an existing engine to such an 

extent that the fixed capital cost of the new and refurbished components exceeds 50 percent of 

the fixed capital cost of a comparable entirely new facility. The fixed capital cost of the new and 

refurbished components and the fixed capital costs of the comparable new facility shall not 

include the cost of replacing components driven by the engine, such as pumps, generators and 

compressors, or other components not connected to the engine or not essential for engine 

operation. For purposes of reconstruction of SI engines, an existing stationary engine is defined 

as including those components necessary for engine operation and those components mounted to 

or within the cylinder block, the engine housings, and engine mounted components. Those 

components that relate to both the engine and the driven equipment shall only be included in the 

fixed capital cost by the pro-rata amount the directly relates to the engine.” 

The commenter (50) argued that stationary industrial engines are intended to be 

overhauled multiple times during their useful life through the replacement of certain parts that 

experience normal wear and tear, and that this standard overhaul process does not mean that it 

would be feasible for the engine to meet NSPS emission standards because the replacement of 

the components during the normal overhaul process does not typically alter the technological 

capabilities of the engine. 

If EPA includes the definition of “reconstruct” in the final rules, commenters 43, 46, 50, 

and 55 recommended that the definition be revised to make sure that all engine components are 

included in the reconstruction determination that are necessary for engine operation. According 

to commenter 55, the proposed definition seeks to restrict the existing stationary engine 
51

components to a narrow prescribed list of included and excluded parts. The commenter (55) 

strongly recommends relying on the 40 CFR General Provisions definition and associated 

determinations. 

Two commenters (43 and 55) said that the definition deviates from EPA’s Applicability 

Determination Index (ADI) and Control Cost Manual, which indicate which costs should be 

included in conducting the reconstruction cost analysis. Commenter 55 claimed that EPA’s 

historical definition of the fixed capital costs associated with reconstruction includes peripheral, 

indirect costs and all depreciable components; whereas the proposed definition is more narrowly 

defined. Commenter 55 asserted that this narrow definition shows a continued reliance by EPA 

on a mobile source or small, packaged engine design, and that this paradigm is inappropriate for 

many stationary units affected by the rule. Furthermore, the commenter (55) stated that the 

proposed definition would also inappropriately and unjustifiably eliminate the provision for 

demonstrating technological and economic feasibility of the reconstructed source meeting the 

applicable standard(s). 

Commenter 55 believes that the term “reconstruct” is not well defined and is not 

technically supported by EPA. If the term is included in the final rules then EPA should explain 

why it is taking a different position compared to previously when in response to comments on 

the 2008 SI NSPS EPA said that the General Provisions definitions are appropriate, commenter 

55 said. Additionally, EPA should provide the basis and rationale for the definition and also 

present the cost and benefit of finalizing this definition. 

If the definition is included in the final rule, commenter 55 requested that the definition 

only affect reconstruction that began after the effective date of the final rule. The commenter 

(55) does not believe that retrospective review is justified and should not be required. Plus, the 
52

commenter (55) asked that EPA also define related terms that are used in the definition in order 

to prevent confusion and to ensure clarity. For example, the terms “refurbish” and “refurbished 

components” are not defined in the proposal, the commenter (55) said, and additionally, if these 

terms are used in the final rule, they need to be distinguished from other terms like routine 

preventative maintenance, repair, overhaul, replacement and rework. 

Commenter 37 supports a specific definition for “reconstruction,” but is concerned about 

EPA’s change in the manufacturing date criteria for reconstructed engines. The commenter (37) 

had previously submitted comments on the original proposed SI NSPS that a specific definition 

for “reconstruction” was needed and the commenter (37) said that it had indicated at that time 

that the current definition in the General Provisions of 40 CFR part 60 was outdated and not 

suitable for stationary engines and that some of the terms in the General Provisions are not 

appropriate for stationary engines. The commenter (37) indicated that it is generally supportive 

of the definition of “reconstruction” that EPA has proposed, but believes that when determining 

the cost to reconstruct an engine, the costs for ancillary components such as external cooling or 

fuel supply should be included in the total new engine costs because such components are 

necessary to make sure the proper fit and function of the new engine. Other commenters (46 and 

50) echoed these comments asserting that the costs for the operation of a comparable new facility 

should include the costs associated with construction, engineering, and equipment necessary for 

operation of the facility, which would be consistent with the historical approach EPA has taken. 

EPA should explicitly recognize commenter 46 said that the costs of the cooler, skid, wiring and 

other equipment necessary for the engine to operate should be included in the reconstruction 

calculation on a pro-rata basis. The commenter (46) additionally recommended that EPA add a 

definition for “comparable entirely new facility” to the definition of “reconstruct” in order to 
53

make sure that the reconstruction cost denominator includes the cost of all components necessary 

for the engine to operate. Similarly, commenter 50 said that EPA should clarify the meaning of 

comparable entirely new facility and in the commenter’s (50) opinion the term should include 

only the engine and the relevant portions of components that are necessary for engine operation. 

 According to the commenter (37), such components would be necessary if an owner was 

to purchase and install a new engine and therefore should be included in the reconstruction 

determination. Similarly, commenter 40 said that the costs of a comparable new engine have not 

been properly defined and a new engine cannot simply with dropped in place, but may require 

different components than the old engine and should also include facility modifications 

necessary in order to accommodate the new engine. Another commenter (39) also agreed with 

previous commenters that ancillary components should be included in the determination. 

Commenter 40 specifically recommended that EPA incorporate the following language into the 

definition in 60.4219 and 60.4248: 

“For the purposes of reconstruction, the costs of a comparable new stationary engine 

include those components mounted to or within the cylinder block, the engine housings, engine 

mounted components, ancillary components and facility modifications necessary to allow a new 

engine to fit and function in the existing engine’s application.” 

One commenter (39) asked what is supposed to be included in the fixed capital cost 

determination, and specifically wanted to know what rates should be used in calculating the total 

labor costs because there is a wide variation. Commenter 39 recommended that if labor is part of 

the fixed capital cost then EPA should define the cost of labor and suggested that EPA specify 

that sources must use the Federal Government minimum wage. 
54

The commenter (37) also said that EPA should also include the technological criteria, in 

addition to the cost criteria in the definition of reconstruction in the final rule for stationary CI 

and SI engines that was part of the original definition of reconstruction. The commenter (37) 

argued that even though a source exceeds the 50 percent capital cost threshold, it may be 

technologically and economically infeasible to meet the emission standards for new engines. 

Commenters 46 and 50 similarly expressed that the technical and economical feasibility criteria 

should be put back into the definition of reconstruction. These are key components of the 

concept of reconstruction included in the original rule, the commenter (50) said, which is 

something that prevents owners from prematurely retiring engines prior to the end of their useful 

life because they cannot meet the standards for new engines in an economic way. To this point, 

EPA has always included the technical and economical criteria in the reconstruction analysis and 

EPA is legally required to explain the rationale for this regulatory decision through data, 

analysis, and demonstrably rational decision-making. Motor Vehicle Manufacturers Ass'n v. 

State Farm Mutual Insurance Co., 463 U.S. 29, 43 (1983). 

Commenters 37 and 40 said that EPA should in the final CI and SI NSPS include the 

criteria currently in 40 CFR 60.15 when determining reconstruction that takes into account the 

technical and economical feasibility of meeting the standards in those two parts. 

 Similarly, commenter 53 said that the proposed definition of reconstruct is a departure 

from how EPA typically defines the term in the General Provisions (40 CFR 60.15(b)), which 

includes language regarding the technical and economical feasibility of meet the standards in 40 

CFR 60.15(b)(2). As other commenters have noted, commenter 53 also does not believe that 

EPA has adequately explained the reasons for proposing a different reconstruction provision. 

The commenter (53) recommended that EPA provide an explanation for this and describe why it 
55

believes the rule should not use the definition from the General Provisions. Further, the 

commenter (53) believes that it is not feasible for existing reconstructed engines to meet Tier 4 

standards without applying retrofit add-on control technologies. As it relates to remote rural 

areas of Alaska, the cost, complexity and risk of utilizing these control technologies on prime 

power plants are not justified considering the minimal PM reduction that would be achieved, in 

the commenter’s (53) opinion. 

 One commenter (26) asked that EPA clarify the requirements that apply to reconstructed 

engines. Specifically, the commenter (26) believes that the language in II.F. of the preamble to 

the proposed rule that states “EPA is also proposing to add provisions to the NSPS that require 

reconstructed engines to meet the emissions standards for the model year in which the 

reconstruction occurs if the reconstructed engine meets any of...” and the language in 60.4201(f) 

and 60.4202(g) that states “Notwithstanding the requirements in [the above paragraphs] of this 

section, stationary CI internal combustion engine manufacturers are not required to certify 

reconstructed engines; however they may elect to do so” appear to be conflicting. The 

commenter (26) asked that EPA clarify if reconstructed engines are required to meet emission 

standards. In an attempt to clarify the requirements for reconstructed engines, the commenter 

(26) suggested that EPA include specific sections with the requirements for reconstructed 

engines to make it clear what applies to these engines. 

 Commenter 43 expressed that it could not provide substantive comments on this issue 

particularly as it relates to suggesting specific changes to the definition because it does not 

understand EPA’s intent with the proposed changes. If EPA identifies the goals in proposing 

revisions affecting the reconstruction determination process, the commenter (43) said it could 

provide additional comments and recommendations. 
56

Response: EPA proposed to add a definition of “reconstruct” to the CI and SI NSPS as an 

attempt to clarify the meaning of reconstruction. EPA’s objective with the proposal was to 

provide a more specific definition applicable to stationary engines rather than the broader 

definition provided in the General Provisions of 40 CFR part 60. The proposed definition was 

intended to clarify how to conduct the reconstruction analysis by specifically proposing to 

include a definition that would be applicable to stationary engines subject to NSPS. EPA 

believed that providing a specific definition applicable only to stationary engines would be 

beneficial by bringing clarity to how reconstruction is determined in the stationary engine 

setting. 

EPA did not expect the proposed change to be controversial, nor did EPA anticipate that 

the proposed change would cause such significant concern among affected sources. However, as 

illustrated in the summary of comments on this issue, several affected stakeholders strongly 

opposed EPA’s suggested changes to the historical definition of reconstruction. Based on the 

extensive concerns provided by commenters and subsequent information EPA has received from 

stakeholders after the proposal, EPA determined that it is appropriate to not include the proposed 

definition of “reconstruct” in the final rule. Instead, EPA is finalizing the rule using the 

definition of “reconstruction” from the General Provisions of 40 CFR part 60. Again, EPA 

intended to provide more guidance than what was originally provided in the rule on 

reconstruction; however, it is nearly impossible to capture all potential situations in a definition. 

EPA believes it is appropriate to continue to rely on the definition in 40 CFR 60.15. Therefore, 

EPA is not finalizing the proposed definition of “reconstruct.” 
57

 9.1.2 Comment: Two commenters (37 and 40) said that EPA should indicate which parts of 

60.15 of the General Provisions in 40 CFR part 60 apply to stationary engines. 

Response: EPA is not finalizing the proposed definition of “reconstruct,” but is instead pointing 

to 40 CFR 60.15 for the definition of “reconstruction.” Therefore, it is not necessary to indicate 

in Table 8 of 40 CFR part 60 subpart IIII and Table 3 of 40 CFR part 60 subpart JJJJ which parts 

of the General Provisions of 40 CFR part 60 apply, because the entire part applies. 

9.1.3 Comment: One commenter (26) suggested that there may be a typo in 60.4219 and 

60.4248 of the proposed rule language and asked if the text “external cooling for fuel supply” 

should be replaced with “external cooling or fuel supply.” 

Response: The language the commenter is referring to was in the proposed definition of 

“reconstruct.” EPA is not including this definition in the final rule, but is pointing to 40 CFR 

60.15 for the definition of “reconstruction.” 

 9.2 Date of Manufacture 

 9.2.1 Comment: A number of commenters (26, 31, 32, 37, 40, 43, 46, 50, and 55) took issue 

with the criteria in the definition of the “date of manufacture” and asked that the definition either 

be removed or revised. 

Commenters 43 and 55 indicated that the criteria in the definition are flawed and 

inconsistent with previous definitions of reconstruction. Commenter 55 stated that it does not 
58

understand EPA’s motivation or objectives for the significant revisions reflected in the proposed 

definition of manufacture date, and therefore could not offer detailed comments to improve 

EPA’s proposal at this time. Commenters 46 and 50 said that EPA has not provided a reasonable 

explanation for the definition either. According to commenter 50, EPA has totally failed in 

meeting its legal obligation to justify applying new engine standards to reconstructed engines 

and contradicts the original SI NSPS, where the commenter (50) cited text indicating that EPA 

recognized the need for different standards for certain reconstructed engines. Several 

commenters (32, 39, 43, 46, 50, and 55) are of the opinion that it is not appropriate to include the 

removal of the crankshaft as criteria for designating an engine being subject to new standards. 

This component is frequently removed during inspection and maintenance, according to 

commenters 32, 39, 46, and 50, who suggested that the criteria related to the crankshaft be 

removed entirely. According to commenter 55, removal of the crankshaft is sometimes 

necessary to access components, but this should not constitute replacement. 

Commenter 39 asked that the replacement of the crankshaft be included in the fixed 

capital cost of reconstruction. According to commenter 39, the crankshaft does not have an 

effect on the engine’s emissions. Further, commenter 39 expressed that if the definition is 

finalized as proposed, it could lead to rebuilding engines properly being impossible due to the 

increase in costs. It could certainly lead to a rebuilding process that is lesser quality where the 

crankshaft is not inspected and new bearings are simply installed without removal and inspection 

of the components, the commenter (39) said. According to the commenter (39), there would be 

enforceability issues as well because during an inspection it would not be possible to determine 

whether the crankshaft had been removed or not. 
59

At a minimum, commenter 32 recommended that EPA at least allow the removal and 

reassembly of the original engine crankshaft. Similarly, commenter 43 said that at a minimum, 

EPA should indicate that replacement of the original crankshaft would trigger a new engine 

classification, not simply the removal of the crankshaft. Also, the definition of “date of 

manufacture” does not consider the feasibility assessment of 40 CFR 60.15(b)(2), the commenter 

(55) said. EPA’s proposed amendments would likely require engine replacement in some cases 

because retrofit control to achieve new engine standards may not be feasible, according to 

commenter 55. Commenter 55 said that the proposed definition is an important issue because it 

could have costly implications with little or no benefit, since emission standards may not be 

achievable (for reconstructed engines categorized as new based on the redefined manufacture 

date). 

One commenter (37) opposes the definition of the “Date of Manufacture” and said that it 

has significant concerns with the definition. The commenter (37) said that removing the 

crankshaft alone should not trigger the need to meet new engine standards. According to 

commenter 37, a relatively new engine might need the crankshaft to be removed or replaced if it 

experiences a main bearing failure, but the engine might not need other extensive reconstruction 

procedures in this case and subsequently the commenter (37) does not believe added 

modifications or engine replacement necessary to meet new engine standards would be justified 

in such a situation. Commenters 37 and 46 do not believe that the removal of the serial number 

from the engine should necessitate the need to comply with new engine standards. That 

provision could restrict the current practical and effective remanufacturing of engines for 

stationary purposes, according to commenter 37. One commenter (50) said that the proposed 

changes to the date of manufacture definition constitute significant concern for industry because 
60

of the cost and operational impacts, plus regulatory confusion the commenter (50) believes the 

changes create. Based on the criteria for assigning a new date of manufacture, the commenter 

(50) argued the possibility that some existing engines may become obsolete due to the 1 g/HP-hr 

NOx emission limit, which for lean burn engines may not be achievable. The commenter (50) 

supported this argument by indicating that lean burn engines cannot use non-selective catalytic 

reduction (NSCR) technology, which reduces NOx emissions and would theoretically make it 

feasible to reach a 1.0 g/HP-hr limit, because of the excess oxygen in the exhaust. The 

technology that is applicable to lean burn engines is oxidation catalyst, but the technology does 

not reduce NOx, the commenter said (50). Therefore, lean burn engines, which typically emit 

around 1.5 to 2.0 g/HP-hr of NOx would become unusable if it receives a new date of 

manufacture, according to commenter 50. Further, the commenter (50) claimed that this would 

lead to rich burn engines replacing lean burn engines because of rich burn engines are capable of 

reducing NOx emissions by NSCR. In the commenter’s (50) opinion, lean burn engines are 

inherently lower emitting, more fuel efficient and emissions are stable. For example, in terms of 

efficiency, the commenter (50) indicated that a rich burn engine utilized about 6,220 million 

British Thermal Unit per year more of fuel than a lean burn engine that was similarly sized. 

Commenter 46 indicated that the serial number could be inadvertently be knocked off 

during transportation or use, and asked that it also not be included as a criteria in the final rule. 

The commenter (46) indicated that it believes that if EPA finalizes a different definition of 

reconstruct, as previously suggested by the commenter (46), that the issue concerning the date of 

manufacture definition is generally resolved since the date of manufacture definition 

incorporates the definition of reconstruct. Again, the commenter (46) emphasized the 

importance of not including the removal of the crankshaft and the reference to the serial number 
61

because those two components do not indicate that an engine has undergone modification at the 

end of its useful life nor to the degree that the engine can technically and economically meet the 

new engine standard. Commenter 46 recommended that EPA make the following revisions to 

the proposed definition of date of manufacture in the final rule: 

“Date of manufacture means one of the following things: 

(1) For freshly manufactured engines and modified engines, date of manufacture means 

the date the engine is originally produced. 

(2) For reconstructed engines, date of manufacture means the date the engine was 

originally produced, except as specified in paragraph (3) of this definition. 

(3) Reconstructed engines are assigned a new date of manufacture if the crankshaft is 

removed as part of the reconstruction or if the fixed capital cost of the new and 

refurbished components exceeds 75 percent of the fixed capital cost of a comparable 

entirely new facility engine (see the definition of “reconstruct”). An engine that is 

produced from a previously used engine block does not retain the date of manufacture of 

the engine in which the engine block was previously used if the engine serial number was 

removed (or the engine otherwise loses its identity), or the engine is produced using all 

new components except for the engine block. In all these cases, the date of manufacture 

is the date of reconstruction or the date the new engine is produced.” 

 One commenter (50) said that the automatic trigger of 75 percent in the fixed capital cost 

of a comparable new engine will most likely make lean burn engines obsolete and subsequently 

requiring it being replaced by a rich burn engine. The commenter (50) indicated that if EPA 

retains the automatic 75 percent trigger in the definition of date of manufacture in the final rule, 

the commenter (50) asked that EPA specify that if reconstructed facilities must meet the engine 
62

standard for existing engines in 60.4233(f) and not the new engine standard, claiming that this 

approach would meet the economically and technically feasible regulatory standard. 

Commenter 50 recommended a very similar definition, except that the commenter (50) 

suggested that paragraph (3) of the definition be revised to read: 

“An engine that is produced from a previously used engine block does not retain the date 

of manufacture of the engine in which the engine block was previously used if the engine is 

produced using all new components except for the engine block.” 

Commenters 43 and 55 recommended a different modified definition, with the following 

changes to paragraph (3) of the Date of Manufacture definition: 

(3) Reconstructed engines are assigned a new date of manufacture if the crankshaft is 

removed as part of the reconstruction or if the fixed capital cost of the new and refurbished 

components exceeds 75 percent of the fixed capital cost of a comparable new engine (see the 

definition of “reconstruct”). An engine that is produced from a previously used engine block 

does not retain the date of manufacture of the engine in which the engine block was previously 

used if the engine serial number was removed (or the engine otherwise loses its identity), or the 

engine is produced using all new components except for the engine block. In all these cases, the 

date of manufacture is the date of reconstruction or the date the new engine is produced.” 

Commenters 43 and 55 asked that if EPA does not remove the crankshaft criteria that 

EPA at least modify the criteria to specify that a new date of manufacture is triggered if the 

crankshaft is replaced (not removed). Commenter 55 also recommends that the following text be 

replaced with simply “the date the engine is placed into service following reconstruction:” 

“An engine that is produced from a previously used engine block does not retain the date 

of manufacture of the engine in which the engine block was previously used if the engine serial 
63

number was removed (or the engine otherwise loses its identity), or the engine is produced using 

all new components except for the engine block. In all these cases, the date of manufacture is the 

date of reconstruction or the date the new engine is produced.” 

According to the commenter (37), those engines are normally built from major 

components from failed or worn-out engines. The failed or worn-out engines are sent as cores to 

the engine remanufacturer, according to the commenter (37), in exchange for a remanufactured 

engine. In the process, the used engine loses its identity and becomes loose parts, and the 

remanufacturer determines which parts can be re-used, according to the commenter (37). A 

mixture of new and re-useable components is used in assembling a remanufactured engine and 

unique serial numbers are assigned with no correlation to the original engines, commenter 37 

said. The entire process provides end-users with cost-effective options the replaces that need of 

rebuilding engines in place or in a repair shop, the commenter (37) said. The commenter is of 

the opinion that using the removal of the serial number as a criterion alone to comply with new 

engine standards would lead to an increase in the number of engine rebuilds performed in lessstructured facilities. The commenter (37) also expressed that it does not concur with the 

requirement that a relatively new engine needing extensive repairs should not need to comply 

with new engine standards. The commenter (37) said that as it previously recommended, 

consideration should be given to take into account the age of the engine. It was recommended by 

the commenter (37) that reconstruction should not be triggered unless the existing engine is at 

least 15 years old compared to the current model year. The commenter (37) believes that a 15-

year threshold would be appropriate as one of the factors in determining if compliance with new 

engine standards is required. Commenter 37 also indicated that there is a precedent for the 15-

year threshold in the replacement engine provisions in 40 CFR 60.4210(i). The commenter (37) 
64

further argued EPA’s proposed definition claiming that it would impose requirements beyond 

those required for nonroad and marine engine that are reconstructed and remanufactured. The 

commenter (37) noted that the definition proposed would lead to a separate and new set of 

requirements for stationary engines only that are refurbished or remanufactured, that would 

change current industry practice by altering the date of manufacture and consequently the 

emission limits that apply for a small group of such engines. The commenter (37) argued that 

since EPA has followed mobile and marine regulations in areas of emission standards, test 

methods and other requirements, it is not correct or appropriate to apply different and more 

stringent requirements on one subset of stationary engines, i.e., reconstructed engines. Instead, 

the commenter (37) recommended that EPA adopt the following definition in the final rules: 

“Reconstructed engines are assigned a new date of manufacture if the engine is more than 

15 years old relative to the current model year and the fixed capital cost of the new and 

refurbished components exceeds 75 percent of the fixed capital cost of a comparable new engine 

(see the definition of reconstruct). For reconstructed engines meeting the above criteria, the date 

of manufacture is the date that reconstruction is commenced.” 

Commenter 40 echoed commenter 37’s points on this matter (commenter 40 also concurs 

with all of commenter 37’s comments), and specifically recommended that EPA remove 

paragraph (3) of the proposed definition of the date of manufacture and apply the reconstruction 

specific emission limits that are already in the CI and SI NSPS, which the commenter (40) stated 

already adequately consider the economically and technically feasible opportunities for updating 

older engines. Alternatively, if EPA does not revise the definition as suggested and the criteria 

that require reconstructed engines to meet the latest standards are retained, the commenter (40) 

expressed EPA should revise the current proposed criteria, including changing the crankshaft 
65

criteria to when it is replaced or refurbished as part of reconstruction. Consistent with prior 

commenters, the commenter (40) does not believe the crankshaft is an appropriate trigger 

because it is routinely removed for inspection and possibly replaced if necessary. Commenter 40 

said that EPA should make sure that in the definition, remanufacturing is treated consistently 

with other rebuilding practices. In the commenter’s (40) opinion, replacing or refurbishing 

crankshafts would only be appropriate triggers if the definition of reconstruction is revised as 

commenter 40 recommended in comment 9.1.1. Also, the proposed trigger related to the 75 

percent fixed capital cost in paragraph (3) of the proposed definition of date of manufacture is 

only acceptable if the definition of reconstruction is revised according to the commenter’s (40) 

recommendation in comment 9.1.1. Moreover, the commenter (40) said that the language in 

paragraph (3) of the definition of date of manufacture related to an engine produced from a 

previously used engine block is completely inconsistent with EPA’s earlier conclusions 

regarding remanufactured engines as discussed in comment 9.1.1 and this language should be 

removed, the commenter (40) expressed. Finally, commenter 40 indicated that a new trigger 

should be included in the provisions that define the date of manufacture, consistent with 

comments from commenter 37 that specify that new emission standards should not be required 

for rebuilt engines unless they are at least 15 years old. The commenter (40) pointed to similar 

provision currently in 40 CFR 60.4210(j). 

One commenter (31) believes that the proposed definition of date of manufacture places 

significant burden on reconstructed engines and said that the criteria in the proposed definition 

seem arbitrary (e.g., the removal of the crankshaft) and trigger emission standards that would be 

applicable in the year the reconstruction occurs. The commenter (31) argued that EPA has not 

sufficiently discussed the justification for revising the requirements for reconstructed engines 
66

and asked that EPA explain the basis and intent for this for the final rule. Alternatively, EPA 

should remove the elements of proposal that supersede the definition of reconstruction in the 

General Provisions of 40 CFR part 60, commenter 31 said. 

One commenter (39) indicated that it does not agree with the language in the date of 

manufacture definition that says “the reconstructed engine consists of a previously used engine 

block with all new components.” The commenter (39) said that there are instances when an 

engine is damaged to the point where a replacement block (and other necessary components) is 

necessary in order for the engine to become operational again. When this occurs, the serial 

number from the replacement block is kept and the engine is rebuilt according to the 

arrangement number of the original engine. If the definition remains as proposed, this means 

that the cost to build an engine utilizing a used block and new components would exceed the 75 

percent capital cost in the definition, according to commenter 39. The commenter (39) added 

that it is the arrangement number that determines the emissions of the engine, which specifies the 

components that are used to build the engine (e.g., pistons, turbocharger, injectors, etc.) and 

stressed that the arrangement number is a more appropriate indicator as to what the engine is 

rather than the serial number. Consequently, the commenter (39) recommended that the above 

quoted phrase be eliminated from the rule and the leave the 75 percent cost threshold as the 

criteria. 

In addition, two commenter (26, 39) pointed out that in the preamble the capital cost 

threshold is 50 percent, while on page 32627 of the FR notice of the regulation (and on page 

32630 of the FR notice), the capital cost threshold is 75 percent. Commenters 32 and 39 said 

that the threshold indicated in the preamble on page 32619 should be increased from 50 percent 
67

to 75 percent because of the significant cost of many replacement engines, commenter 32 added. 

According to the commenter (32), replacement engines can cost more than $50,000. 

Commenter 55 contends that if EPA retains the new definitions of reconstruction and 

date of manufacture, applicability should not be retrospective – that is, previous reconstruction 

determinations relying on definitions in 40 CFR 60.15 should not be required to revisit or reevaluate previous determinations. 

Response: As with EPA’s proposed definition of “reconstruct,” the proposal to add a definition 

for the “date of manufacture” led to a significant concern with affected stakeholders as reflected 

in this comment summary. Commenters were generally not opposed to having a definition for 

the “date of manufacture,” but were against some of the criteria used in the proposed definition. 

 Based on the comments related to removal of the crankshaft, EPA agrees that including 

the engine crankshaft language in the definition of “date of manufacture” would not be 

appropriate. EPA does not wish to trigger more stringent standards for engines that are simply 

undergoing regular maintenance. Notably, solely removing the engine crankshaft is not an 

indication that a substantial amount of work has been conducted on the engine to the extent that 

it should have to meet to more stringent emission standards. Consequently, EPA is not including 

the crankshaft criteria in the definition of “date of manufacture” in the final rule. 

 Regarding comments opposing the inclusion of the serial number in the definition of 

“date of manufacture,” EPA agrees that it would be appropriate to exclude that specific criterion 

in the final rule. EPA does not wish to require more stringent standards for reconstructed 

engines solely due to the possibility that in some cases, the serial number might not be available, 

for instance, it may have been knocked off during transportation, use or maintenance, or if the 
68

engine was acquired and it did not have a tag. EPA is not interested in penalizing affected 

sources, where information simply is not available or missing based on a technicality, by 

subjecting them to more stringent standards. Importantly, the lack of the engine serial number is 

not an indicator that the engine has undergone significant modification to the point where it 

should be subject to more stringent standards. Therefore, in the final rule, EPA has not included 

the serial number criteria in the definition of “date of manufacture.” 

 EPA believes that finalizing a cost threshold of 75 percent in the definition of “date of 

manufacture” is appropriate. Based on the comments received, it appears that the majority of the 

issues surrounding the date of manufacture concept were related to the crankshaft being included 

in the definition. Since EPA is not including the engine crankshaft as a determining factor for 

assigning an engine a new date of manufacture, EPA believes that most of the issues brought up 

by commenters would be resolved. EPA also agrees that the cost threshold analysis should be 

consistent with what is used for reconstruction, and therefore specifies in the final rule that the 

cost of the new and refurbished components should be compared to the fixed capital cost of a 

comparable entirely new facility. Commenter 50 indicated to EPA in a meeting on October 26, 

2010, that having a consistent cost threshold analysis would alleviate its concerns with the 75 

percent threshold.9

 

Commenter 39 expressed concern with the requirement that a reconstructed engine 

consisting of a previously used engine with all new components be given a new date of 

manufacture. EPA disagrees that a bare engine block with all new components should not be 

required to meet the emission standards applicable for a new engine. That type of engine 

rebuilding would significantly extend the life of the engine, and EPA believes it is appropriate 

 

9

 Memorandum from Tanya Parise, EC/R to Melanie King, EPA. Summary of the October 26, 2010 Meeting with 

the Gas Compressor Association Regarding the Proposed Amendments to the SI NSPS for Stationary Engines. 

November 10, 2010. EPA-HQ-OAR-2010-0295. 
69

that the engine meet the most stringent emission standards, and that the equipment necessary to 

meet those standards can be incorporated into the extensive rebuilding of the engine. EPA also 

notes that 40 CFR 60.4210(i) includes replacement engine provisions for stationary CI engines 

replacing existing equipment that is less than 15 years old. 

The commenters who pointed out that there was a typo in the preamble concerning when 

reconstructed engines would be subject to more stringent standards are correct. EPA notes that 

there was a typo on page 32619 of the preamble to the proposed rule in the middle column. The 

language in section II.F. that read “The fixed capital cost of the new and refurbished components 

exceeds 50 percent of the fixed capital cost of a comparable new engine” should have read “The 

fixed capital cost of the new and refurbished components exceeds 75 percent of the fixed capital 

cost of a comparable new engine” consistent with the proposed definition of “date of 

manufacture” in proposed 60.4219 and 60.4248. 

 In response to the commenter who believes that previous reconstruction determinations 

conducted using definitions in 40 CFR 60.15 should not be required to be revisited or reevaluated, EPA notes that any provisions finalized under this rulemaking are not retroactive. 

EPA has no control over what State agencies or other regulatory authority may require, but in 

any event, EPA is not including a separate definition for reconstruction in the final rule, but is 

instead pointing to the General Provisions definition. 

 

9.2.2 Comment: One commenter (50) said that the criteria for reconstruction are different in 40 

CFR part 63, subpart ZZZZ, and in the proposal under 40 CFR part 60, subpart JJJJ. This creates 

confusion because an engine could be defined as reconstructed under the NSPS and has to meet 

the new engine standard of 1.0 g/HP-hr of NOx or 3.0 g/HP-hr of NOx, depending on the 
70

threshold for fixed capital cost. The same engine under 40 CFR part 63, subpart ZZZZ, may not 

be considered reconstructed, and would still be subject to existing requirements under that rule, 

the commenter (50) said. Accordingly, the commenter (50) stated, this leads to conflicting and 

duplicative requirements between a new or reconstructed NSPS engine and an existing NESHAP 

engines. This also directly conflicts with EPA’s attempts to streamline and simplify compliance, 

which it stated in the response to comments for the final SI NSPS/NESHAP consolidated 

rulemaking. 

Response: EPA is not finalizing the proposed definition of “reconstruct,” but is instead pointing 

to 40 CFR 60.15 for the definition of “reconstruction.” This is consistent with the definition of 

“reconstruction” used for 40 CFR part 63, subpart ZZZZ, which points to the definition in 40 

CFR 63.15. Therefore, the commenter’s issue is resolved.

 9.3 Installed 

 9.3.1 Comment: Two commenters (37 and 55) thought that the definition of “installed” in 

sections 60.4248 and 60.4219 of the proposed NSPS should be deleted or modified. EPA 

proposed to add the following definition: 

 “Installed means the engine is placed and secured at the location where it is intended to 

be operated; piping and wiring for exhaust, fuel, controls, etc., is installed and all connections are 

made; and the engine is capable of being started.” 

 The commenter (55) indicated that installation has typically meant the start of site 

construction, as opposed to when the engine is ready to operate. The commenter (55) expressed 
71

that it did not anticipate this change and was of the opinion that if the new definition is included 

in the final rule it should only be applied from the effective date of the rule and not retroactively. 

 Commenter 37 indicated that part of the definition is appropriate, i.e., in terms of having 

the engine “placed and secured at a location where it is intended to operate” for defining 

“installed.” However, the commenter (37) does not agree with the rest of the definition as that 

states “...the piping and wiring for exhaust, fuel, controls, etc., is installed and all connections 

are made; and the engine is capable of being started.” 

The commenter (37) recommended that the final definition read as follows: 

“Installed means the engine is placed and secured at the location where it is intended to 

be operated.” 

Because stationary engines are often part of a larger facility, the engines may be placed at 

the location in advance of completing the rest of the facility and this could be significantly prior 

to utilities being completed (including local permits and building inspections). In the 

commenter’s (37) opinion, creating the foundation and placing the engine at the location 

indicates major commitment by the owner and the commenter (37) does not believe that it is 

necessary to finalize the remaining connections in order to demonstrate the owner’s intent, and 

such connections are typically more related to the larger construction project than the engine 

itself. 

Response: EPA disagrees that the proposed definition of “installed” should not be included in 

the final rule. The proposed definition of “installed” is intended to describe the point when the 

engine is capable of being operated at the site. This is consistent with EPA’s previous position, 
72

notably in the response to comments on the original CI NSPS proposal.10 Specifically, EPA 

stated in response to comment 1.3 that the term “install” refers to “the date the engine is installed 

at the operator site.” This clearly indicates that EPA did not mean for the word “install” to be 

equivalent to “commence construction,” and EPA explicitly stated that EPA did not want 

“install” to be interpreted to mean “commence construction.” 

 EPA agrees with commenter 37’s recommendations regarding the definition of 

“installed.” EPA agrees that installation should be defined as the engine has been placed and 

secured where it is intended to be operated, and that the engine does not have to be capable of 

being started before it can be considered installed, since the final piping and wiring may not be 

completed until well after the engine is secured in its permanent location. 

 9.4 Certified Emissions Life 

 9.4.1 Comment: One commenter (26) indicated that it is supportive of EPA proposing to use 

“certified emissions life” in place of “useful life.” Commenter 26 said that it is common that 

“useful life” and “service life” are thought to be the same thing, but incorporating the term 

“certified emissions life” will remove confusion surrounding this issue. The commenter (26) 

asked that EPA also incorporate the term into other rules, where appropriate. Commenter 26 

said that the transition should be timed to change of model year to avoid scrappage of stocks of 

emissions labels using the older term. The commenter (26) said that because drawings for 2011 

model year emissions labels are already made and being obtained, the commenter (26) 

recommended that the terminology does not take effect until 2012 model year or later. 

 

10 Memorandum from Jaime Pagán, EPA to EPA Docket EPA-HQ-OAR-2005-0029. Response to Public Comments 

on Proposed Standards of Performance for Stationary Compression Ignition Internal Combustion Engines. 
73

Response: EPA’s revision to change the term “useful life” to “certified emissions life” does not 

create any substantive change to the requirements under the rule and EPA is not making any 

changes to the labeling requirements themselves. Also, incorporating the term “certified 

emissions life” into other regulations is beyond the scope of this rule. 

 9.5 Emergency Engines 

 9.5.1 Comment: Multiple commenters (24, 30, 32, 34, 41, 42, 43, 44, 47, and 55) had comments 

regarding the proposed definition of an emergency engine in the CI and SI NSPS, particularly as 

it relates to demand response operation. The proposed language reads as follows: 

“You may operate your emergency stationary ICE up to 50 hours per year in nonemergency situations, but those 50 hours are counted towards the 100 hours per year provided 

for maintenance and testing. The 50 hours per year for non-emergency situations cannot be used 

for peak shaving or to generate income for a facility to supply power to an electric grid or 

otherwise supply power as part of a financial arrangement with another entity; except that 

owners and operators may operate the emergency engine for a maximum of 15 hours per year as 

part of a demand response program if the RTO or equivalent balancing authority and 

transmission operator has determined there are emergency conditions that could lead to a 

potential electrical blackout, such as unusually low frequency, equipment overload, capacity or 

energy deficiency, or unacceptable voltage level. The engine may not be operated for more than 

30 minutes prior to the time when the emergency condition is expected to occur, and the engine 

operation must be terminated immediately after the facility is notified that the emergency 

condition is no longer imminent. The 15 hours per year of demand response operation are 

counted as part of the 50 hours of operation per year provided for nonemergency situations. The 
74

supply of emergency power to another entity or entities pursuant to financial arrangement is not 

limited by this paragraph (d)(4), as long as the power provided by the financial arrangement is 

limited to emergency power.” 

 One commenter (43) supports clarifications made to the definition. Two commenters (43 

and 55) disagree with the provisions in 60.4243(d)(4), which limit operating hours for various 

types of operation. According to commenters 43 and 55, the proposed time limit for grid support 

is unnecessarily restrictive, and may, in the commenters’ (43 and 55) opinion impact the viability 

of demand response programs that are important for providing energy reliability. Another 

commenter (24) also indicated that the 15 hours proposed to be allowed for demand response 

operation is too restrictive. Although emergency demand response programs are rarely called 

because of Independent System Operators (ISO) tariff requirements, an engine needs to be 

allowed to participate in demand response programs for more than 15 hours per year, commenter 

24 said. 

 One commenter (30) is in agreement that emergency engines should be allowed to 

operate in emergency demand response programs. However, the commenter (30) is opposed to 

EPA’s proposal of a 15 hour restriction on such operation because it may prevent emergency 

engines from being able to participate in emergency demand response programs because in order 

to qualify, the engines must meet the ISO tariff requirements, which specify the minimum 

number of hours the engine will be able to operate. The commenter (30) referred to the petition 

for reconsideration submitted to EPA on May 27, 201011, on the final NESHAP, which describes 

in detail the commenter’s justifications. The petition for reconsideration and supporting 

documentation were also submitted under this proposed rule. In summary, the commenter (30) 

 

11 Letter from David M. Friedland, Beverage and Diamond, P.C., to Ms. Lisa Jackson, Administrator. Petition for 

Reconsideration of National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal 

Combustion Engines, Final Rule. May 27, 2010. 
75

rationalized not limiting emergency demand response operation to 15 hours per year for the 

following reasons: 

 Emergency demand response programs are beneficial to the environment, according to 

commenter 30; 

 During dispatch of demand response for capacity and energy emergencies, ISO must 

follow North American Electric Reliability Council standards; 

 As stated above, allowing only 15 hours per year for emergency demand response 

operation has the potential of emergency engines not qualifying to participate in 

emergency demand response programs; 

 It is rare that emergency demand response programs are called, according to commenter 

(30) and as a result the chance these engines will be operated to the maximum number of 

hours is small; 

 The rationale EPA has provided for supporting the 15 hours appears to reflect a 

misinterpretation of comments previously submitted in support of demand response; 

 A number of States allow emergency demand response operation and none of them 

restrict operation under such programs to 15 hours per year; and 

 EPA set a precedent under the greenhouse gas reporting final rule for the use of 

emergency engines in emergency demand response programs. 

Commenter 30 recommended that EPA specify that emergency engines can operate for a 

maximum of 60 hours per year or the minimum hours required by the ISO tariff, whichever is 

less. 

In this definition, two commenters (43 and 55) recommended that EPA should strike the 

15 hours per year limitations for demand response programs because operation is only authorized 
76

if warranted by a legitimate emergency regarding power availability. Commenter 43 indicated 

that EPA should also make this change to the NESHAP when EPA has an opportunity to do so. 

If EPA does not eliminate the 15 hours restrictions, the commenter (55) argued that EPA should 

justify such a decision and provide the environmental and cost benefit of this restriction. 

 According to one commenter (32), in general, industry’s interpretation of the definition of 

an emergency engine is that the power source must be abruptly interrupted in order to be 

classified as an emergency. In the commenter’s (32) opinion, the definition is a reactionary one 

that does not work well in emergency planning and certain emergencies can be anticipated by the 

use of weather event tracking and utility monitoring. In such cases, provisions can be made in 

advance to minimize the impact of the emergency, the commenter (32) said, who further cited a 

recent tornado storm that was tracked in Wisconsin 30 to 60 minutes prior to impact, and 

information like that is used to prepare emergency generators to prevent actual power 

interruption. The commenter (32) added that frequently utility networks who observe rapid 

decline in reserve capacities will take preventative action in order to prevent grid collapse by 

setting up agreements with large electricity consumers to “go off the grid” for a short duration. 

According to the commenter (32), the maximum hours defined in the agreements are between 80 

and 100 hours, but all those hours are rarely used, in the commenter’s (32) experience. The 

commenter (32) emphasized the importance of including such flexibility for national grid 

reliability and safety and does not believe it would deter from environmental goals. Specifically, 

the commenter (32) recommended that EPA retain the 50 hours per year for non-emergency 

purposes. Further, the commenter (32) recommended that in 60.4211(f)(4), EPA delete the 

limitation of not operating the engine more than 30 minutes prior to the time when an emergency 

is expected to occur and the requirements to shut down the engine immediately following the 
77

event. Similarly, another commenter (34) disagrees with these limitations in both 60.4211(f)(4) 

and 60.4243(d)(4) and indicated that it would expect disputes with respect to the term 

“immediately.” The commenter (34) asked why 30 minutes would be acceptable, but why 31 

minutes would not be. Also, the commenter (34) wanted to know what criteria are supposed to 

be used to determine when the emergency condition is expected to occur and to determine when 

the emergency condition is no longer imminent. The commenter (34) indicated that it believes 

that most entities are not interested in operating emergency generators any longer than necessary. 

The commenter (34) recommended that EPA remove the time restrictions or keep them only as 

guidelines and require records only to indicate the time and purpose of generator operation. 

Commenter 32 argued that emergency situations often lead to operational decisions that 

are difficult and that vary on a case-by-case basis, and the commenter (32) believes this should 

be left within the management of the 50 hour limit. The commenter (32) is of the opinion that 

the allowance provided for demand response operation should be increased to a minimum of 100 

hours. According to the commenter (32), this is a typical length of the agreement between the 

utility and the facility. Finally, the commenter (32) added that one could argue that EPA could 

allow an indefinite period for demand response operation that would be subject to audits of this 

type of operation. The commenter (32) said that the key factors of needing demand response 

operation is overall grid reliability and frequency of disruptive weather events and are matters of 

public record. 

One commenter (47) asked that EPA allow 60 hours per year for demand response 

operation arguing that 15 hours is too restrictive in ensuring national grid reliability. 

Commenters 24 and 30 also requested that EPA specify that 60 hours are allowed. The 

commenter (47) believes that emergency demand response operation is infrequent and only to 
78

prevent brownouts and blackouts. The power generated during these events is not supplied to the 

grid, but is used at the facility, the commenter (47) stated. Allowing demand response operation 

prevents rolling brownouts and blackouts from happening and without it reduction in power and 

power outages would increase, according to commenter 47. The commenter (47) cited language 

in the proposed amendments claiming that EPA acknowledged the need for emergency demand 

response programs in 60.4211(f)(4) and 60.4243(d)(4). The commenter (47) recommended that 

the demand response limit be removed or alternatively that EPA revise 60.4243(d)(4) to read: 

“...owners and operators may operate the emergency engine for a maximum of 60 hours per year 

or the amount of time required by the Independent System Operator tariff, whichever is less, as 

part of a demand response program...” Three commenters (24, 30, and 47) also recommended 

that EPA remove the provision that counts the hours used for emergency demand response 

purposes towards the 50 hours per year in non-emergency situations. 

 One commenter (41) stated that the proposed amendments are in direct conflict with 

section 69.3.5 of the Midwest ISO Federal Energy Regulatory Commission (FERC) approved 

Open Access Transmission and Energy and Operating Reserves Markets Tariff. The Midwest 

ISO’s Tariff, which has been approved by FERC, allows entities to obtain demand resources for 

generating capacity during emergency conditions, which frequently includes engines, the 

commenter (41) said. The Tariff states at 69.3.5(iv) and (v) that a demand resource that qualifies 

as a capacity resource must be able to operate (during emergency conditions where the reliability 

of the electric grid needs to be maintained) at least five times for at least 4 continuous hours per 

event during the summer season. Therefore, any engine that could qualify to be considered for 

such operation has to be able to be operated for a minimum of 20 hours per year, the commenter 

(41) said, who added that similar requirements are including in other Regional Transmission 
79

Organizations (RTO). The commenter (41) requested that EPA allow additional time for 

demand response operation consistent with qualification requirements developed by RTO and 

approved by FERC. As such, the commenter (41) asked that EPA allow such operation to be at 

least 20 hours per year and that such operation be considered an emergency situation as opposed 

to a non-emergency situations and accounted for accordingly. The commenter (41) 

acknowledged the potential environmental impact, but asked that EPA recognize the significant 

of balancing environmental concerns with the importance of maintaining grid reliability during 

emergency conditions. 

 One commenter (42) asked that EPA reconsider the language in the emergency engine 

definition that restricts emergency demand response operation to 15 hours per year. One 

commenter (44) asked that EPA delete the definition of emergency demand response in the 

proposed definition of emergency engine. Also, the commenter (44) asked EPA to clarify 

between emergency response units and price response units in the definition because there are 

differences between how emergency generator operations are treated by ISO. The commenter 

(44) suggested that EPA review the following definition of “real-time emergency generation 

resource” from the ISO New England, Inc. Transmission, Markets and Services Tariff, FERC 

Electric Tariff No. 3, issued December 22, 2004: 

 “Real-Time Emergency Generation Resource is Distributed Generation whose Federal, 

State and/or local air quality permits limit operation in response to requests from the ISO to the 

times when the ISO implements voltage reductions of five percent of normal operating voltage 

that require more than 10 minutes to implement. A Real-Time Emergency Generation Resource 

must be capable of: (i) curtailing its end-use electric consumption from the New England grid 
80

within 30 minutes of receiving a Dispatch Instruction; and (ii) continuing that curtailment until 

receiving a Dispatch Instruction to restore consumption.” 

 The commenter (44) recognizes the need for emergency generation and on-peak demand 

response to provide reliable electricity delivery, and acknowledges, as demonstrated in 2003, the 

substantial health and economic impact associated with wide-scale grid failure. Regardless, 

operating emergency engines to create electricity for on-peak demand during high electric 

demand days (HDDE) creates significant public health impacts, such as high emission rates of 

ozone precursors and air toxics, commenter 44 said. Such high emission rates significantly make 

problems worse on air quality that is already impaired during HDDE. Consequently, the 

commenters (42 and 44) believe that EPA should discourage the use of emergency generators 

unless it is for a true power emergency. 

 For real emergencies (including blackouts and brownouts, including periods of 5 percent 

voltage reduction), the commenter (55) does not believe that EPA should have to limit the 

number if the definition of “emergency” is specific and restrictive enough to prevent operating 

for price-response purposes. Commenter 42 also cited the above tariff and argued that current 

market rules and definitions established by ISO-New England (ISO-NE) are sufficient enough to 

adequately restrict the use of emergency engines for financial reasons. Therefore, the 

commenter (44) recommended that EPA finalize a definition of emergency that specifically lays 

out the conditions, including periods of 5 percent voltage reduction, illustrated by the ISO-NE 

cited above. Commenter 42 similarly requested that EPA adopt rules similar to those in effect in 

New England through the ISO-NE Tariff or allow regions to define their own programs that 

restrict the use of emergency engines in a way that is consistent with EPA’s goals without strictly 

limiting the number of hours of participation. Further, the commenter (44) requested that EPA 
81

coordinate with FERC to determine the estimated energy and environmental benefit from 

implementing this definition of emergency on a national level to be used by all ISO. Also, the 

commenter (44) recommended that EPA set standards that will provide incentives to dispatch 

non-generating demand response resources prior to the dispatch of polluting demand response 

resources. Additionally, the commenter (44) said that EPA should make sure that control 

technology matches the intended use of emergency engines that are used to meet on-peak 

demand for quick start capacity and require that emission controls are operating at full efficiency 

as soon as possible and no later than 10 minutes after engine start-up or the time recommended 

by the engine manufacturer if add-on controls such as SCR is used. 

 One commenter (42) encouraged EPA to review material developed by Synapse Energy 

Economics, Inc., referenced in the Petition for Reconsideration filed by CPower, EnergyConnect, 

EnerNOC and Innoventive Power. The material concluded in fact that availability of these 

resources could improve air quality when used to provide system reserves, under certain dispatch 

models, the commenter (42) said. According to the commenter (42), in these cases, emergency 

engines would be providing non-spinning quick start reserves in place of old load-following 

boilers providing spinning reserves through their operation at minimum load. The commenter 

(42) argued that emergency engine resources are vital parts of the resource mix that displace 

other types of power and play an important role in ensure electric grid reliability. 

 Another commenter (24) argued similar points that it is critical to allow stationary 

emergency engines to participate in demand response programs in order to stabilize the electric 

grid. Consistent with other commenters, EPA should not institute regulations that conflict with 

existing emergency demand response programs that are also endorsed by several States with no 

restrictions on the numbers of hours, the commenter (24) said. The commenter (24) cited to the 
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ISO-NE, and to language in various New England State regulations addressing emergency 

engines. The commenter (24) indicated that under the ISO-NE, operators are fully aware that 

operation is only permitted during emergency conditions and such conditions are clearly defined 

when the ISO-NE declares Operating Procedure (OP) 4, Action 12.12 According to the 

commenter (24), the emergency demand response program is totally independent of the ISO-NE 

price response program, and emergency engines are only contracted to operate under OP 4, 

Action 12 conditions and not in the price response program. Per the commenter (24), in New 

England, OP 4, Action 12 has rarely been declared. Further, the commenter (24) said, the 

emergency demand response program also includes cutting power to other devices at a facility, 

such as minimizing heating, ventilation and air conditioning (HVAC) and lighting loads shutting 

off factory machines. The commenter (24) added that over the last few years, the States of 

Connecticut, Massachusetts, Rhode Island, and New Hampshire have revised their emergency 

engine definitions to allow these engines to participate in the ISO-NE emergency demand 

response program. According to the commenter (24), the State of Vermont has implemented a 

policy allowing emergency engines to participate in ISO-NE emergency demand response 

programs and Maine permits engines on a case-by-case basis if engines exceed permit 

thresholds. The commenter (24) cited the definitions of emergency engines from several New 

England State regulations, highlighting language related to emergency demand response program 

provisions, adding that the States do not limit the hours of operation for engines participating in 

the ISO-NE emergency demand response program. The commenter (24) also discussed the RTO 

of much of the Mid-Atlantic and Midwest region of the country, namely PJM Interconnection 

who has an equivalent program called the Emergency Load Response Program (ELRP). 

 

12 Under Forward Capacity Market (“FCM”) this Action is now known as Action 6 Real Time Emergency 

Generation (“RTEG”). 
83

According to the commenter (24), it is more advantageous to prevent a blackout by utilizing a 

group of emergency generators for a short time rather than losing the grid, in which case the 

commenter (24) said would mean that all emergency generators in the State would have to 

operate for several hours of perhaps days. Engines used under the ELRP will not be synched 

with the grid, commenter 24 said, but will only be turned on when the RTO declares an 

emergency on the ELRP, consequently reducing the demand on the grid. In addition, owners are 

asked to reduce their power by limiting their HVAC and light usage, for instance, the commenter 

(24) said. The ELRP is engaged under the provisions in the PJM Manual 13 Emergency 

Operations for a PJM Declared Emergency, a condition where the RTO alerts electric 

distributors that there is an emergency or that an emergency is expected and it is necessary to 

follow procedures under PJM Manual 13 Emergency Conditions. Again, the commenter (24) 

said that ELRP has seldom been declared and stressed that it is strictly in place for emergency 

situations, plus it is not associated with other PJM programs related to financial gain, e.g., 

economic response or peak shaving. Between the years 2003 and 2009, the ELRP has been 

called only five times where the event lasted between 3 and 5 hours. The commenter (24) 

referred to how emergency engines area treated in various States, such as Maryland, 

Pennsylvania, Virginia (allows a maximum of 60 hours for emergency engine operation under 

ELRP), Ohio, Illinois, West Virginia, Allegheny County (the division handles ELRP requested 

on a case-by-case basis and has so far approved permits with 60 hours as the limit), and Indiana, 

who include provisions for emergency demand response operation in their regulations, and once 

again noted that these States typically do not limit the hours allowed for operation during the 

ELRP. The Electric Reliability Council of Texas (ERCOT) has the Emergency Interruptible 

Load Service (EILS), a program developed as a last resort in order to prevent electric grid 
84

failure, the commenter (24) said. The program is part of the Electrical Emergency Curtailment 

Plan (EECP) and is expected to be called during a Stage 3 emergency. At that point, everything 

else has been tried according to the commenter (24) and to prevent a rolling blackout, emergency 

generators are used to power facilities, reducing demand on the grid. The program is designed 

for a maximum number of six dispatches per year for a total of 24 hours per year at most, the 

commenter (24) said. In Texas, most emergency engines operate under a permit by rule and 

under this, operation in the ERCOT EILS Program is not restricted and there are no hour limits 

for such participation either. 

 The commenter (24) argued that EPA precedent exists for allowing emergency engines to 

operate in demand response programs without restrictions, e.g., in EPA’s Mandatory Reporting 

of Greenhouse Gases rule, EPA exempted emergency engines from reporting greenhouse gases. 

EPA defined emergency generators as follows in that rule (74 FR 56387): 

 “[a]n emergency generator operates only during emergency situations, for training of 

personnel under simulated emergency conditions, as part of emergency DR procedures, or for 

standard performance testing procedures as required by law or by the generator manufacturer.” 

 The commenter (24) said that EPA did not include any restrictions on the emergency 

demand response hours in that rule. The commenter (24) closed by emphasizing the importance 

of EPA not finalizing requirements that are inconsistent with how many regions of the country 

handle emergency demand response. 

Response: EPA proposed to amend the definition for “emergency stationary internal combustion 

engine” and the allowances for maintenance/testing and non-emergency operation for such 

engines to be consistent with the provisions promulgated in the NESHAP for existing stationary 
85

reciprocating internal combustion engines (RICE) at 40 CFR part 63, subpart ZZZZ. EPA is 

only finalizing a portion of the proposed revisions to the emergency engine definition. EPA is 

finalizing the provision allowing 50 hours of non-emergency service for stationary CI engines 

subject to the NSPS, in order to make the emergency engine provisions for new CI engines 

consistent with those for new SI engines and existing CI and SI engines. At this time, EPA is not 

finalizing the proposed provision allowing 15 hours for demand response operation for 

emergency stationary engines. EPA included a similar provision for emergency engines in the 

March 3, 2010, amendments to the stationary RICE NESHAP (75 FR 9648), and subsequently 

proposed to amend the stationary engine NSPS to be consistent with the stationary RICE 

NESHAP. EPA received two petitions for reconsideration of the 15-hour allowance for demand 

response in the stationary RICE NESHAP, and is currently reconsidering its decision to allow 

emergency engines to operate for 15 hours per year as part of an emergency demand response 

program. EPA is deferring taking final action on including this provision in the stationary ICE 

NSPS pending the resolution of the reconsideration process on the stationary RICE NESHAP. 

EPA will address this issue as it affects the CI and SI NSPS emergency engine provisions as part 

of that reconsideration process. 

9.5.2 Comment: Two commenters (43 and 55) noted some concerns with the proposed definition 

of emergency engine. In order to prevent confusion, commenters 43 and 55 recommended that 

EPA remove the sentence in the proposed definition that reads “Stationary SI ICE used for peak 

shaving are not considered emergency stationary ICE,” which the commenter (55) believes 

conflicts with the last sentence of the definition. 
86

Response: As discussed in the response to comment 9.5.1, EPA is not finalizing the proposed 

definition for emergency stationary internal combustion engine at this time. Regardless, EPA 

disagrees with the commenters and does not believe the commenters’ recommendation to remove 

the language as suggested is appropriate. Peak shaving is not the same as grid support and 

therefore EPA does not believe those two sentences conflict. 

 9.5.3 Comment: One commenter (37) agrees that it is appropriate to allow emergency engines 

to participate in demand response programs for a limited number of hours. The commenter (37) 

concurs that only a very limited amount of time should be allowed to demand response purposes 

and opposes an amount higher than what EPA proposed. The commenter (37) is of the opinion 

that if a generator is to be used for demand response, peak shaving or other non-emergency use, 

those engines should meet the standards applicable to non-emergency engines. 

Response: No response is needed. 

 9.5.4 Comment: Two commenters (21 and 35) indicated that healthcare facilities have been 

significantly impacted by restrictions in the original CI NSPS. An increase in power 

interruptions due to utilities not having the infrastructure needed to manage increased loads 

during inclement weather and power anomalies has worsened the problem, according to the 

commenter (35). This presents a danger to healthcare facilities that have consequently entered 

into demand response agreements with utilities in order to deal with unreliable power, the 

commenter (35) said. Issues related to power will increase and according to the commenter (35) 

will likely exceed the 15 hours per year. Therefore, commenter 37 urged EPA to revise 40 CFR 
87

60.4211(f)(4) to remove the 15 hours limitation and replace it with allowing any period of period 

under a demand response program. The commenter (35) also recommended the stipulation that 

the engine cannot be operated for more than 30 minutes prior to the time when the emergency 

condition is expected to occur be removed, specifically suggesting the following revisions: 

“The engine may not be operated for more than 30 minutes prior to the time when a 

period of time that the emergency condition is expected to exist occur, and then the engine 

operation must be terminated immediately after the facility is notified that the emergency 

condition is no longer imminent. The 15 hours per year of demand response operation are not 

counted as part of the 50 hours of operation per year provided for non-emergency situations.” 

Two commenters (21 and 35) do not believe that incorporating these suggested changes 

into the final rule will detract from the intent of the proposed changes and indicated that these 

changes will provide an increased level of protection for healthcare facilities’ patients and staff. 

The commenters (21 and 35) provided with its comment letter a publication13 on diesel 

generators and noted how the report indicates how diesel generators may be a clean and cost 

effective solution to the power crisis. 

Response: As discussed in the response to comment 9.5.1, EPA is not addressing the issue of 

emergency demand response, including the restriction on operation more than 30 minutes prior 

to an emergency, at this time. EPA is deferring taking final action on including this provision in 

the stationary ICE NSPS pending the resolution of the reconsideration process on the stationary 

RICE NESHAP. 

 

13Backup Generators (BUGS):The Next Smart Grid Peak Resource.U.S. Department of Energy. 4/15/2010. 

http://www.netl.doe.gov/smartgrid/referenceshelf/whitepapers/BUGS_The%20Next%20Smart%20Grid%20Peak%2

0Resource%20(April%202010).pdf. 
88

 9.5.5 Comment: One commenter (33) indicated that it thinks that additional clarification and 

language is needed to adequately describe demand response operation and peak shaving. The 

commenter (33) said that how industry describes demand response operation does not appear to 

match how EPA has described it in the proposed amendments and the commenter (33) believes 

this can cause confusion as far as which engines are for emergencies and which are for peak 

shaving. Because the proposed rule allows emergency engines to participate in demand response 

programs, according to the commenter (33), sources may think their engines would be 

considered emergency engines. The commenter (33) pointed out however, that the demand 

response programs developed by the utility industry utilize these engines for non-emergency 

purposes to reduce the cost to provide power during high demand.14 According to commenter 

33, the only motivation for end-use customers to participate in demand response programs is for 

financial gain and participation does not provide additional stability for the end-use customer 

because it already has an emergency engine to provide power during a blackout. The commenter 

(33) said that there is additional confusion in the proposed amendments because the commenter 

(33) does not believe that EPA has adequately described the emergency conditions that qualify 

an engine to participate in demand response operation. The commenter (33) referred to the 

North American Electric Reliability Corporation’s (NERC) Capacity and Energy Emergencies 

(Standard EOP-002-2) regarding energy emergency alerts, suggesting that this document15 might 

be helpful to EPA in identifying emergency conditions that would allow the use of engines for 

emergency energy response operation, which states that an “Energy Emergency Alert is an 

emergency procedure, not a daily operating practice...” Subsequently, the commenter (33) 

 

14http://pjm.com/markets-and-operations/demand-response.aspx, http://pjm.com/markets-and-operations/demandresponse/~/media/markets-ops/dsr/20100707-dsr-hight-load-day-report.ashx, and http://pjm.com/markets-andoperations/demand-response/~/media/markets-ops/dsr/demand-response-fact-sheet.ashx. 15http://www.nerc.com/files/EOP-002-2.pdf.
89

recommended that Alert 2 status, as detailed in this document, be required prior to emergency 

engines being allowed to be utilized for demand response operation. In the commenter’s (33) 

opinion, a copy of the Alert 2 report would be sufficient to demonstrate that the engine qualified 

demand response operation and the report is typically available online through NERC’s website. 

 In terms of peak shaving, commenter 33 indicated that it understands this might be 

necessary during peak demand, but the commenter (33) said that such operation is not an 

emergency. The use of these engines during a non-emergency situation yields financial benefit 

without having to control emissions, the commenter (33) said. Even if each engine is allowed to 

operate for only 15 hours per year, PJM Interconnection, an RTO with an emergency demand 

reserve of 2,144 megawatt (MW), can result in a large influx of emissions in a very short time 

period, the commenter (33) said. For example, using AP-42 emission factors for stationary CI 

engines below 600 HP, the commenter (33) estimated that the 15 hours of operation within 

PJM’s fleet would equate to about 668 tons per year (tpy) of NOx emissions, 144 tpy of carbon 

monoxide (CO) emissions, 47 tpy of PM10 emissions and 53 tpy of total organic compounds. 

The commenter (33) believes that these engines should be subject to the same requirements that 

apply to non-emergency engines. At the very least, the commenter (33) recommended that EPA 

clarify the difference between peak shaving and demand response. 

Response: As discussed in the response to comment 9.5.1, EPA is not addressing the issue of 

demand at this time. EPA is deferring taking final action on including this provision in the 

stationary ICE NSPS pending the resolution of the reconsideration process on the stationary 

RICE NESHAP. As noted in the response to comment 9.5.2., EPA agrees that there is a 
90

significant difference between peak shaving and emergency demand response, and allowance of 

the latter for any amount of time does not imply allowance of the former. 

 9.5.6 Comment: Two commenters (24 and 34) said that EPA should change the reference from 

60.4211(e) to 60.4211(f) in the definition of an emergency engine in 60.4219 in the proposed 

rule. 

Response: EPA agrees that the proposed definition should have referenced 60.4211(f) in the 

proposed rule. 

9.5.7 Comment: One commenter (28) noted significant concern with regards to EPA’s proposal 

to allow emergency engines to participate in emergency demand response operation even for a 

limited amount of time. The commenter (28) believes that allowing emergency demand response 

operation could have detrimental effects on Delaware’s ability to attain and maintain compliance 

with National Ambient Air Quality Standards (NAAQS) and strongly disagrees that demand 

response should be included as emergency use. The commenter (28) emphasized the importance 

of true emergency operation, as for example backup power at a hospital when the main 

electricity is unavailable or at chicken farms where heating or cooling is crucial to avoid deaths. 

On the other hand, the commenter (28) argued that emergency generators are being utilized for 

other reasons where electric utilities have created demand response programs that are, in the 

commenter’s (28) opinion, contrary to the anticipated use of emergency power generation, which 

negatively impact air quality. These emergency units emit HAP and emit high levels of NOx on 

a mass and rate basis, the commenter (28) said, arguing that the time when these engines operate 
91

(i.e., during demand response) is during the worst conditions for developing ground-level ozone. 

The commenter (28) cited to an example where in Delaware, a demand response program 

consists of roughly 225 uncontrolled generators less than 300 KW. The owners of these engines 

are according to commenter 28 in agreement with the utility to provide power during peak 

demand scenarios and receive lower electric rates in return. Per commenter 28, these engines 

have typically operated on very hot sunny summer days and emit a substantial amount of HAP 

and above 1.6 tons of NOx in a 3-hour period, the commenter (28) said. Finalizing the definition 

of emergency engine as proposed will lead to these engines directly impacting air quality with 

respect to ground-level ozone, the commenter (28) believes. If EPA allows this type of operation 

during peaking times, it would circumvent and undercut Delaware’s efforts and progress in 

reducing emissions. The commenter (28) contended that if emergency generators in the entire 

Northeast are allowed to operate without controls in demand response programs, emissions 

would be substantial and have detrimental effects on ground level ozone. The commenter (28) 

pointed to a 2003 Northeast States for Coordinated Air Use Management (NESCAUM) report16

on stationary diesel engines, which indicate that there are about 26,890 emergency diesel engines 

with the ability to generate 8,760 MW of emergency capacity in the NESCAUM region. The 

commenter (28) cited to a recent event where PJM activated the ELRP on July 7, 2010, where 

the event lasted 4 hours for most areas that participated. Using available information on the 

actual capacity utilized that day under ELRP, reasonable assumptions regarding the number of 

emergency generators that participated in the event, and the type of emissions controls installed 

on the generators, the commenter (28) estimated that the event could have generated close to 218 

tons of NOx. For comparison, the commenter (28) said that Delaware’s entire statewide peak 

 

16 Stationary Diesel Engines in the Northeast: An Initial Assessment of the Regional Population, Control 

Technology Options and Air Quality Policy Issues. Northeast States for Coordinated Air Use Management. 
92

ozone season daily NOx emissions were 182 tons in 2005. The commenter (28) argued that 

using other assumptions in this estimation, e.g., by assuming that the generators were older and 

smaller, it is possible that the amount of NOx emitted that day could have been on the order of 

272 tons. However, the commenter (28) said that these are conservative estimates and it is likely 

that not all the load shed was due to emergency generators. In fact, information the commenter 

(28) was provided with showed that the NOx emitted was 46 tons on July 7, 2010. Regardless 

what the figure is the commenter (28) said it is a substantial amount. 

 The commenter (28) indicated that it wished to model the emergency demand response 

using the CALGRID air quality model, but due to additional research necessary in order to 

complete the assessment, it was not feasible in the timeframe required to provide comments on 

the proposed rule to finish the modeling. Consequently, the commenter (28) asked that EPA 

conduct its own analysis to model the effects of July 7, 2010, to understand the impacts of 

emergency demand operation. The commenter (28) indicated that according to an inquiry 

conducted on EPA’s AIRNow website, monitors in the Philadelphia non-attainment area on July 

7, 2010, indicated that 15 ozone monitors exceeded the 75 parts per billion (ppb) 8-hour ozone 

NAAQS (based on preliminary data). Further, the commenter (28) claims that there would have 

been NAAQS exceedances on almost all of the days where the ELRP was in effect. The 

commenter (28) pointed to other events that it believes demonstrate the negative environmental 

effect of allowing emergency generators to operate. 

The commenter (28) submitted additional information following its original comment 

letter to support claims that diesel generators directly cause or contribute to violations of EPA’s 

1-hour nitrogen dioxide (NO2) NAAQS, which became effective in April 2010. These 

comments are represented as commenter 45. The commenter (45) submitted information on a 
93

modeling analysis that indicate that diesel emergency and peak shaving engines cause and 

contribute to 1-hour NO2 levels as high as 4 times the NAAQS. The commenter (45) reiterated 

its point that diesel engines that are aggregated for demand response purposes have substantial 

negative impacts on ozone levels (specifically in terms of NO2) and should not be allowed to 

participate, in an uncontrolled fashion, in demand response programs. 

Response: As discussed in the response to comment 9.5.1, EPA is not taking any action 

regarding emergency demand response at this time. EPA is deferring taking final action on 

including this provision in the stationary ICE NSPS pending the resolution of the reconsideration 

process on the stationary RICE NESHAP. 

9.5.8 Comment: One commenter (52) provided additional comments (the commenter’s original 

comments are reflected under commenter 30-see Table 1 of this document) in rebuttal to 

comments submitted by commenter 28. The commenter (52) thought that the concerns from 

commenter 28 are misguided in that commenter 28: 1) confuses emergency demand response 

with economic demand response; 2) confuses reserve margin with emergency conditions; 3) 

significantly overestimates emissions from emergency demand response; 4) misstates the 

Synapse Study; and 5) inappropriately uses emissions decrease during a blackout as a reason to 

prohibit emergency demand response. Regarding item 1), commenter 52 said that emergency 

demand response programs are only used for grid emergencies, whereas economic demand 

response are dispatched by the utilities or ISO in response to high prices or are self-selective by 

end users in response to prices. These two programs are substantially different, commenter 52 

said and EPA should treat them as such. The commenter (52) does not believe that commenter 
94

28 has made a distinction between these two types of programs; emergency demand response is 

operation as a last resort to avoid blackouts and economic demand response is operation such as 

peak shaving or other types of non-emergency operation. The commenter (52) reiterated that 

emergency demand response is tightly controlled under NERC regulations for the sole purpose 

of responding to grid emergencies. The examples provided by commenter 28, which the 

commenter (28) indicates is emergency demand response, is, in fact, economic demand response 

(see page 2, second paragraph, and page 3, first full paragraph of EPA-HQ-OAR-2010-0295-

0028), and the language in EPA’s NSPS and NESHAP regulations specifically exclude peak 

shaving and other economic gain while operating emergency generators. In response to item 2), 

commenter 52 said that contrary to what commenter 28 said, there is no buffer when the electric 

need is above the required reserve margin. According to commenter 52, the grid operator only 

calls emergency demand response when reserves are used up or close to be used up. In response 

to item 3), commenter 52 said that commenter 28 estimated that NOx emissions were between 

218 and 272 tons during the demand response event on July 7, 2010. However, the commenter 

(52) said, commenter 28 incorrectly assumed that all that emergency demand response was a 

result of emergency generator operation. In fact, 75 percent of the emergency demand response 

on that day was a result of curtailment (e.g., turning down lights, reducing HVAC needs, etc.) 

Assuming that 25 percent originated from emergency generators, NOx emissions are estimated to 

be less than 46 tons that day and possibly even less. The Synapse Energy Economics Study17, 

which commenter 52 submitted as part of its petition for reconsideration for the NESHAP and 

attached to the commenter’s (52) comments on this proposed rulemaking, evaluated the impacts 

of demand response and energy efficiency programs in New England using an electric system 

 

17 Modeling Demand Response and Air Emissions in New England. Prepared by: Geoff Keith, Bruce Biewald, 

David White and Mike Drunsic. Synapse Energy Economics. Prepared for U.S. Environmental Protection Agency. 

August 2003. Revised: September 4, 2003. EPA-HQ-OAR-2010-0295-0030.3. 
95

dispatch model. The conclusion of the study was that emergency demand response improves air 

quality. Commenter 52 disputed commenter 28’s claim that the report assumed that the nonemergency generators were gas-fired, first by stating that the report also indicates that if all 

demand response operation is from diesel engines, there is still a net air quality benefit. The 

benefit increases if some of the fuel is assumed to be gas, the commenter (52) said). Secondly, 

the commenter (52) said that emission factors from eight different types of operation were used 

(gas-fired combined cycle, oil-fired combined cycle, gas-fired combustion turbine, oil-fired 

combustion turbine, and coal, gas, oil, and wood-fired steam plants). According to commenter 

52, the Synapse Study concluded that “when the DR resource is used to meet reserve 

requirements, the result is more efficient unit commitment, reduce operation of oil- and gas-fired 

steam units and increased operation of combined-cycle units in New England.18 The commenter 

(52) also cited the following additional conclusion from the study: 

“New England has a small amount of quick-start capacity relative to the regional peak 

load compared to most other control areas. Many analysts have noted that this requires large 

power plants to operate more than they would otherwise have to in order to maintain sufficient 

operating reserves – capacity that can be provided quickly in response to unplanned losses of 

capacity. A key goal of this work for EPA was to verify that large units were indeed being 

operated more than necessary in New England to meet reserve requirements, to gauge the 

probable emission impacts of this dynamic, and to estimate potential emission reductions that 

additional DR could provide if it were used to meet operating reserve requirements.19” 

Commenter 52 stated that according to the report, demand response is used for reserves 

there are substantial decreases of criteria pollutant emissions, even under the assumption that all 

 

18 Id. See page 2. 

19 Id. See page 4. 
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fuel used is diesel (NOx decreased 23 tons, SO2 decreased 216 tons, carbon dioxide decreased 

31,400 tons, PM2.5 decreased 12.5 tons, and PM decreased 21.2 tons.20

Regarding item 5), commenter 52 said that it is not realistic to sacrifice electricity for 

reduced emissions. Commenter 52 said that it is nonsensical to use as an argument that 

emissions actually go down during a blackout in order to support the preclusion of emergency 

demand response. Grid failure is a serious concern, which affects public health and safety and 

can also cause severe environmental damage. 

Response: As discussed in the response to comment 9.5.1, EPA is not taking any action 

regarding emergency demand response at this time. EPA is deferring taking final action on 

including this provision in the stationary ICE NSPS pending the resolution of the reconsideration 

process on the stationary RICE NESHAP. 

 9.6 Freshly Manufactured Engines 

 9.6.1 Comment: Two commenters (37 and 40) believe that EPA should remove the reference to 

previously used parts in the definition of a freshly manufactured engine. The proposed definition 

reads as follows: 

”Freshly manufactured engine means an engine that has not been placed into service. An 

engine becomes freshly manufactured when it is originally produced. Note that this includes an 

engine that is produced using some previously used parts if it does not retain its original 

identity.” 

 

20 Id. See page 13. 
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One commenter (40) asserted that if the last sentence of the proposed definition is 

finalized as proposed, it will disproportionately impact stationary engine remanufacturing and 

would be inconsistent with section 202(a)(3)(D) of the CAA. 

One commenter (37) opposes the inclusion of previously used engines in the definition, 

noting that it differs from the marine and nonroad engine definitions, and impacts the standards 

for previously used and remanufactured engines. In the commenter’s (37) opinion, including 

used parts as part of freshly manufactured products is fundamentally wrong in that those parts 

have previously be in service. The commenter (37) expressed the importance of remanufactured 

engines and the value of the remanufacturing process to the industry. The proposed definition 

would eliminate the option of remanufacturing by applying a new date of manufacture to such 

engines requiring the remanufacturing process to meet the same requirements (including 

certification, where applicable) as the process where new engines are built on an assembly line 

using completely new parts, the commenter (37) said. The commenters (37 and 40) indicated 

that the definition does not take into consideration the technical or cost feasibility of updating 

existing components to meet the latest standards, as if they were new components. Used 

components are not new components and the commenter (37) consequently argued that 

remanufactured engines with used parts should not be considered new or freshly manufactured 

engines. According to the commenters (37 and 40), remanufactured engines are more similar to 

rebuilt or reconstructed engines (as opposed to new or replacement engines) and should be 

treated as such. Replacement engines are built entirely from new components according to 

certified methodologies, commenter 40 said, and it is therefore more appropriate to group newly 

manufactured engines and replacement engines together. Conversely, remanufactured, rebuilt 

and reconstructed engines are built from a combination of used and new components and should 
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therefore be grouped together, the commenter (40) asserted. According to commenter 40, this 

would be consistent with EPA’s prior findings concerning remanufactured and rebuilt engines 

and with statutory obligations under section 202(a)(3)(D) of the CAA. Commenter 40 said that 

EPA is authorized to regulate “rebuilding practices” for heavy-duty engines, but EPA can only 

implement requirements for rebuilding practices if the Administrator does the following: 1) 

studies such practices, 2) finds, based on that study, that rebuilding practices “cause, or 

contribute to, air pollution which may reasonably be anticipated to endanger public health or 

welfare taking costs into account,” and 3) provides sufficient lead time for technology to develop 

to meet the new regulations. The commenter (40) cited an EPA study21 conducted to investigate 

the rebuilding and remanufacturing industry under section 202 of the CAA and a broader 

industry characterization22 conducted under EPA’s direction, which the commenter (40) clearly 

indicated that remanufacturing is a form of “out-of-frame” overhaul or rebuild. Accordingly, the 

commenter (40) said, EPA’s view is consistent with the commenter’s (40), i.e., that 

remanufactured should be grouped with rebuilt and reconstructed engines. 

The commenter (40) cited the following EPA conclusion from the section 202(a)(3)(D) study, 

which commenter 40 believes is clear and unequivocal: 

“Based on the study findings, regulations to control rebuilding practices applicable to 

current technology heavy-duty engines are not warranted to ensure that rebuilt engines meet the 

emission certification standards that applied to the engines when new. [Emphasis added by 

commenter 40]. The study demonstrated that current technology rebuilt engines generally emit 

below the standards applicable when such engines were new. While rebuilding extends the 

 

21 See for example pages 6-7 of Industry Characterization: Nonroad Heavy Duty Diesel Engine Rebuilders. ICF 

Incorporated, 1997. EPA-HQ-OAR-2005-0119-0004. 

22 See for example Notice of Agency Completion of Study Regarding Heavy-Duty Engine Rebuilding Practices and 

Availability of Documents, 60 Fed. Reg. 42881, 42882 (Aug. 17, 1995). 
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actual life of engines, it does not appear that the emissions characteristics of current engines 

deteriorate as a result of rebuild. Furthermore, most emissions critical components are currently 

replaced or adjusted during a typical engine rebuild.”

 Again, the commenter (40) stressed that including the sentence at issue would necessitate 

certification of remanufactured engines to current standards and fundamentally change EPA’s 

previous regulatory treatment of these engines. Further, finalizing the definition as proposed 

would reduce or remove the numerous benefits associated with remanufacturing in terms of 

including decreased use of natural resources, improved energy efficiency, decrease in carbon 

emissions, and minimizing landfill space, according to the commenter (40). This would also 

contravene EPA’s prior findings regarding remanufactured engines and be inconsistent with 

section 202(a)(3)(D) of the CAA, commenter 40 said. If EPA determines that requirements are 

necessary for remanufactured engines, the commenter (40) stated that EPA should first 

reevaluate previous conclusions made and make a finding that a new approach is necessary. The 

commenter (40) recognizes that section 202 of the CAA applies to mobile sources and that 

previous conclusions made by EPA are related to mobile engines, however, the commenter (40) 

believes the same conclusions should be applicable to stationary engine rebuilding practices. 

The commenter (40) also made the point that EPA has previously adopted emission standards, 

test methods and other requirements for stationary engines where it modeled mobile source 

requirements for nonroad and marine engines. 

Subsequently, two commenters (37 and 40) recommended that EPA remove the last 

sentence of the definition and incorporating the following definition in the final rule: 

“Freshly Manufactured Engine means an engine that has not been placed into service. An 

engine becomes freshly manufactured when it is originally produced.” 
100

 Commenter 40 argued similar points to commenter 37 (and also concurs with all 

comments submitted by commenter 37) stating that finalizing the definition as proposed would 

eliminate the positive benefits associated with remanufacturing. The last part of the proposed 

definition would subject the remanufacturing process to the same requirements that a new engine 

using entirely new parts is subject to, including certification, where applicable, the commenter 

(40) said. Consequently, the benefits associated with a remanufactured engine would be lost. 

Response: EPA agrees that it is appropriate to not include the reference to previously used parts 

in the definition of freshly manufactured engine in the final rule. EPA does not wish to get 

newly manufactured engines mixed up with rebuilt and remanufactured engines. Consequently, 

EPA is finalizing the following definition in 40 CFR 60.4219 and 60.4248 of the final rule: 

“Freshly manufactured engine means an engine that has not been placed into service. An engine 

becomes freshly manufactured when it is originally produced.” 

10.0 Miscellaneous 

10.1 Comment: Two commenters (43 and 55) said that EPA should resolve currently 

outstanding issues related to interpretation and implementation of 40 CFR part 60, subpart JJJJ, 

requirements in this final rulemaking. One commenter (55) said that it has previously submitted 

to EPA a list of questions and issues1

 that need to be resolved either in the rule itself or through 

guidance material. The list of questions and issues were based partly on workshops commenters 

43 and 55 participated in, which were designed to help operators implement the rule 

requirements. The commenter (55) said that EPA needs to resolve these issues and referred back 

to the original March 10, 2010, letter for additional details on the issues. Commenter 43 stated 
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similarly that it has also submitted a list of issues to EPA over the last few years that need 

clarification, e.g., the commenter (43) submitted a letter to EPA in March 2008. The commenter 

(43) urged EPA to address these issues, acknowledging that some of them may be most 

appropriately covered in guidance material, but that others should be addressed in the rulemaking 

itself. 

Response: The focus of the proposed amendments was on 40 CFR part 60, subpart IIII. EPA’s 

intention was not to make substantive changes to 40 CFR part 60, subpart JJJJ at this time. 

However, EPA took the opportunity under these proposed amendments to propose minor 

clarifications and corrections to that subpart for consistency with 40 CFR part 60, subpart IIII. 

EPA is only promulgating non-substantive and miscellaneous minor changes to 40 CFR part 60, 

subpart JJJJ under this final rule. EPA is currently discussing other substantive changes to 40 

CFR part 60, subpart JJJJ in a separate context. 

10.2 Comment: Two commenters (43 and 55) said that the initial notification requirements in 

the SI NSPS need to be clarified, because current rules inadvertently imply that multiple 

notifications are necessary, which are burdensome to operators. According to the commenter 

(55), 60.4230 defines the date that construction commences as the date the engine is ordered, and 

60.7(a)(1) requires notification of the date of construction within 30 days. This 30 day time 

period for initial notification is problematic, according to commenter 55, for engine orders where 

siting or engine delivery does not occur within this time period, given the definition in 60.4230. 

Additionally, the commenter (55) stated that operators may feel obligated to submit initial 

notifications to multiple agencies, since an ordered engine could possibly be sited in one of 
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several states. Thus, commenter 55 suggested that EPA clearly define expectations and 

regulatory intent for notifications for the various parties involved (owner, operator, lessee, etc). 

Response: As EPA has previously indicated, the focus of the proposed amendments was on 40 

CFR part 60, subpart IIII, and EPA does not intend to address substantive changes to 40 CFR 

part 60, subpart JJJJ, aside from those intended to retain consistency with subpart IIII, in this 

proceeding. EPA will address these issues separately. 

10.3 Comment: Two commenters (43 and 55) said that EPA should include concentration-based 

limits for engines between 25 HP and 100 HP in the SI NSPS. According to the commenters (43 

and 55), engines in this size range will need to be tested in some cases and having concentrationbased limits would provide a less costly compliance options. The commenters (43 and 55) said 

that the concentration-based limits should correspond to the g/HP-hr limits in 60.4233(d). For 

example, the 2.8 g/HP-hr would equate to 230 ppm by volume, dry basis of NOx at 15 percent 

oxygen based on the conversions used in Table 1 and 60.4233(f)(4) of the SI NSPS, the 

commenters (43 and 55) said. 

Response: EPA agrees that it would be beneficial to include concentration-based alternatives for 

engines between 25 HP and 100 HP that are subject to the SI NSPS. However, EPA would have 

to propose to add ppm standards to the SI NSPS as alternatives to the g/HP-hr standards first. 

EPA plans to do this in a separate proceeding. 
103

10.4 Comment: Two commenters (43 and 55) indicated that in Table 1 of 40 CFR part 60, 

subpart JJJJ, there are errors in the mathematical symbols for less than and greater than. For 

instance, “500≥HP<1,350” should be corrected to “500≤HP<1,350” and “25>HP<130” should 

be corrected to “25<HP<130.” EPA should review and correct the symbols in Table 1 of 40 

CFR part 60, subpart JJJJ, the commenters (43 and 55) said. These errors are important to fix, 

according to the commenter (55), because they result in duplicative requirements for several 

engine size categories. 

Response: EPA agrees with the commenters and has corrected the errors in the mathematical 

symbols that were previously incorrect in the rule. 

10.5 Comment: Two commenters (43 and 55) said that EPA needs to address the fact that engine 

exhaust flowrate measurement is not required when conducting a compliance test for 

concentration-based standards. However, determining the flowrate is a requirement in Table 2 of 

40 CFR part 60, subpart JJJJ, and the commenters (43 and 55) recommended that EPA clarify 

that this determination is only necessary for engines complying with mass-based limits (i.e., 

g/HP-hr limits). The commenters (43 and 55) suggested that EPA revise Table 2, column 3, 

requirements (1)(a)(iii), (1)(b)(iii), and (1)(c)(iii) to read: 

 “If necessary (i.e., for compliance with mass-based emission standards, determine the 

exhaust flowrate of the stationary internal combustion engine exhaust.” Failure to address this 

minor revision, according to the commenter (55), will result in implementing agencies requiring 

unnecessary tests and incurring associated costs. 
104

Response: EPA agrees with the commenter that it is appropriate to make this correction because 

taking a flowrate measurement is not needed for sources that are complying with the 

concentration-based standards. EPA has made it clear in Table 2 of 40 CFR part 60, subpart JJJJ 

that determining the exhaust flowrate of the engine is not required when complying with the 

concentration-based standards for NOx, CO and volatile organic compounds. 

10.6 Comment: Two commenters (43 and 55) said that EPA should clarify in the final SI NSPS 

how sources should determine compliance with the NOx + hydrocarbons (HC) limits. For 

natural gas engines between 25 HP and 100 HP the rule indicates that HC is assumed to be zero 

for performance tests for natural gas engines. The commenters (43 and 55) asked that EPA 

clarify that HC emissions can be assumed to be zero from natural gas emergency engines as well. 

If this is not the case, the commenters (43 and 55) said that EPA should clarify how HC is 

defined, i.e., which species should be included and which should be excluded. 

Response: As EPA has previously indicated, the focus of the proposed amendments was on 40 

CFR part 60, subpart IIII, and EPA did not intend to make substantive changes to 40 CFR part 

60, subpart JJJJ. 

10.7 Comment: Two commenters (43 and 55) asked that EPA make clarifications in the final SI 

NSPS with respect to standards and time constraints associated with import or initial installation 

of engines prior to 40 CFR part 60, subpart JJJJ applicability dates. Specifically, the commenters 

(43 and 55) thought that the language in 60.4236 is confusing where it uses “the previous model 

year” as opposed to “any previous model year” or “previous model years.” Commenter 55 said 

that it appears that paragraphs 60.4236(a) through (d) are supposed to provide 2 years from the 
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initial applicability date for import or initial installation of an engine manufactured prior to the 

applicability date. However, the commenter (55) said, by using the language “the” previous year 

in section title, that literally means only engines that are imported or installed within the prior 

year from the dates provided in 60.4236(a) through (d), i.e., within a time period where the 

standard already applies. The commenter (55) also said the emission standard that applies is not 

clear and consequently recommended that EPA revise the title of 60.4236 to state that it applies 

to “previous model years” and in the text, it should be clarified that the Stage 1 standards are the 

standards that apply under this section. 

Response: EPA agrees with the commenter that clarifying language related to the provisions 

limiting import and installation of engines past certain model years is appropriate. EPA 

understands that the title of 60.4236 of 40 CFR part 60, subpart JJJJ was confusing and has 

consequently modified the title of that section. In the final rule, the title of 40 CFR 60.4236 

reads as follows: “What is the deadline for importing or installing stationary SI ICE produced in 

previous model years?” 

10.8 Comment: Two commenters (43 and 55) said that the schedule for conducting initial 

compliance tests should be consistent with 40 CFR part 63, subpart ZZZZ requirements. 

Uncertified engines under the SI NSPS are required to conduct performance tests within 60 days 

after achieving the maximum production rate, and according to the commenter (55); this would 

typically be about 60 days after startup. Certified engines have up to 1 year to conduct the 

performance test under the SI NSPS and engines subject to testing under the NESHAP have 180 

days to perform the test. The commenters (43 and 55) were of the opinion that EPA should 
106

make the rules consistent and therefore recommended that the initial test for uncertified engines 

should be 180 days under the SI NSPS. 

Response: EPA is not making substantive changes to 40 CFR part 60, subpart JJJJ at this time. 

Consequently, EPA will address the scheduling of performance test issue when other issues 

related to the SI NSPS are dealt with at a later date. 

10.9 Comment: Two commenters (43 and 55) said that the SI NSPS requires engines above 500 

HP to test every 8,760 hours of operation or every 3 years. For engines that operate constantly, 

this equates to a test once a year, the commenters (43 and 55) said. However, the rule does not 

provide for a scheduling allowance, that historically, according to the commenter (55), testing 

requirements often include, e.g., within 30 days of the “due date.” The commenter (55) believes 

this adds complexity particularly for the engines that operate around the clock and said that the 

annual date for conducting the test would move progressively forward every year. Commenters 

43 and 55 felt that it is reasonable to allow a test schedule that remains constant over time, e.g., 

the test could be scheduled within 30 days of the annual anniversary, in order to reduce the 

scheduling burden and to account for issues related to the ability to achieve “peak load,” 

maintenance downtime, test contractor availability, and so on. The commenters (43 and 55) 

recommended that EPA allow the yearly test to be conducted a certain window (e.g., 30 days) of 

the deadline triggered by 8,760 operating hours. 
107

Response: EPA is not making substantive changes to 40 CFR part 60, subpart JJJJ at this time. 

EPA will address the frequency and timing of performance testing at a later date when other 

issues related to the SI NSPS are addressed. 

10.10 Comment: Two commenters (43 and 55) are of the opinion that the SI NSPS should 

include a burn-in period for new, modified, reconstructed and rebuilt engines, consistent with the 

NESHAP. The commenters (43 and 55) indicated that the 200 hour engine burn-in period can 

prevent damage to the catalyst, which is possible during the initial engine operating hours. Not 

having this provision could lead to damage and premature failure of the catalyst, according to the 

commenters (43 and 55). The commenters (43 and 55) also said that without this provision, 

equipment is run in a mode that can void emission guarantees, significantly increase control 

costs, increase waste streams from damaged catalyst, and lead to unnecessary emissions. 

Commenter 55 believes that it is not appropriate to compare stationary engines to mobile source 

engines in terms of an engine burn-in period and according to the commenter (55), catalyst 

vendor recommend including a burn-in period to guarantee proper catalyst performance and life. 

The commenters (43 and 55) urged EPA to include the same burn-in period allowance in the SI 

NSPS as was provided in the NESHAP because the same issues apply to units complying with 

either regulation. The commenters (43 and 55) recommended that the following specific 

language be added to the SI NSPS: 

 “For new, reconstructed, modified, and rebuilt stationary RICE, deviations from the 

emission or operating limitations that occur during the first 200 hours of operation from engine 

startup (engine burn-in period) are not violations.” 
108

Response: EPA will address burn-in period issues related to the initial hours of operation for 

new engines with catalytic aftertreatment when EPA other issues related to the SI NSPS are 

addressed. 

10.11 Comment: Two commenters (43 and 55) said that EPA should define the terms 

“maximum engine power” and “peak load” in 40 CFR part 60, subpart JJJJ. The commenters 

(43 and 55) indicated that for engines less than 25 HP it is clear what the term “maximum engine 

power” means because the SI NSPS points to the definition of the term in 40 CFR 90.3. 

However, for engines above 25 HP, commenters 43 and 55 said that it is unclear what maximum 

engine power means. Based on conversations the commenters (43 and 55) have had with 

manufacturers and operators of engines, it seems that maximum engine rating should be the 

nameplate rating provided by the manufacturer, regardless of specific site conditions like 

elevation. However, the commenters (43 and 55) pointed out, the term “nameplating rating” 

does not have a clear definition either, and that term (or “engine rating”) should be clarified in 40 

CFR part 60, subpart JJJJ also. 

Response: EPA will address what the terms “maximum engine power” and “peak load” mean 

when other substantive changes are made to 40 CFR part 60, subpart JJJJ. At this time, however, 

EPA is not making significant changes to the SI NSPS, but is only making minor corrections to 

the subpart while addressing substantive revisions to 40 CFR part 60, subpart IIII. 

10.12 Comment: Two commenters (43 and 55) asked that EPA clarify what documentation is 

necessary under 60.4245(a)(3) of 40 CFR part 60, subpart JJJJ for certified engines. The 
109

commenters (43 and 55) wanted to know what the operator is required to maintain in terms of 

documentation both where the certified engine is operated as certified and as non-certified. 

Response: EPA will clarify the documentation requirements when other substantive changes are 

made to 40 CFR part 60, subpart JJJJ. 

10.13 Comment: Two commenters (43 and 55) asked that EPA revise 60.4233(f)(4) of 40 CFR 

part 60, subpart JJJJ to specifically indicate the implementation dates and emission limits that 

apply to the 500 HP to 1,350 HP subcategory of engines. The commenters (43 and 55) said that 

there is confusion regarding these engines that were manufactured from July 1 to December 31, 

2007, that are modified or reconstructed. The commenters (43 and 55) specifically 

recommended that EPA add a new paragraph (iv) as follows: 

 “(iv) Prior to January 1, 2008, for non-emergency lean burn natural gas and LPG engines 

with a maximum engine power greater than or equal to 500 HP and less than 1,350 HP.” In 

addition, the commenters (43 and 55) asked that EPA revise paragraph (i), which is for engines 

500 HP and above, to exclude the engines that the commenters (43 and 55) are recommending be 

specifically addressed in a new paragraph (iv). 

Response: EPA agrees with the commenters’ suggestions and has included a fourth paragraph in 

60.4233(f)(4) of the final rule as well as clarified in paragraph (i) that the engines addressed in 

60.4233(f)(iv) are not included in 60.4233(f)(4)(i). 
110

10.14 Comment: One commenter (55) indicated that it supports EPA proposed revisions to 

60.4243 of 40 CFR part 60, subpart JJJJ, to more clearly identify the requirements that apply to 

certified engines and non-certified engines. 

Response: No response is needed. 

10.15 Comment: One commenter (55) expressed that it supports EPA posting a redline version 

of proposed changes to the rule in the docket. 

Response: No response is needed. 

10.16 Comment: One commenter (37) urged EPA to provide incentives for engines that are 

efficient under the CI NSPS. Specifically, the commenter (37) recommended that EPA follow 

other rules such as the NSPS for steam generator boilers and stationary combustion turbines, and 

allow increases in criteria pollutant emissions for engines that are energy efficient. The 

commenter (37) argued that providing such an incentive for engines would highlight the 

importance of energy efficiency and reducing fuel consumption and greenhouse gas emissions. 

In addition, this would level the playing field for engines that compete against boilers and 

turbines that currently can utilize energy efficiency provisions under their NSPS, the commenter 

(37) said. 

Response: EPA encourages energy-efficient engines, but providing incentives for stationary CI 

engines that are efficient is beyond the scope of this rulemaking. The standards as promulgated 
111

are feasible and EPA sees no reason to change the standards. EPA may consider making such 

accommodations for efficiency and lower greenhouse gas emissions in the future when EPA 

reviews the standard under 111(b)(1)(B) of the CAA.