6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2008-0708, FRL-XXXX-Y]

RIN 2060-AQ58

National Emission Standards for Hazardous Air Pollutants for 

Reciprocating Internal Combustion Engines; New Source 

Performance Standards for Stationary Internal Combustion Engines

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

SUMMARY: The EPA is proposing amendments to the national 

emission standards for hazardous air pollutants for stationary 

reciprocating internal combustion engines under section 112 of 

the Clean Air Act. The proposed amendments include alternative 

testing options for certain large spark ignition (generally 

natural gas-fueled) stationary reciprocating internal combustion 

engines, management practices for a subset of existing spark 

ignition stationary reciprocating internal combustion engines in 

sparsely populated areas and alternative monitoring and 

compliance options for the same engines in populated areas. The 

EPA is also proposing to include a limited temporary allowance 

for existing stationary emergency area source engines to be used 

for peak shaving and non-emergency demand response. In addition, 

the EPA is proposing to increase the hours that stationary 
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emergency engines may be used for emergency demand response. The 

proposed amendments also correct minor mistakes in the preexisting regulations. 

DATES: Comments. Comments must be received on or before [INSERT 

DATE 45 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER], or 30 

days after date of public meeting if later.

Public Meeting. If anyone contacts us requesting to speak at a 

public meeting by [INSERT DATE 7 DAYS AFTER DATE OF PUBLICATION 

IN THE FEDERAL REGISTER], a public meeting will be held on 

[INSERT DATE 15 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. If you are interested in attending the public 

meeting, contact Ms. Pamela Garrett at (919) 541-7966 to verify 

that a meeting will be held. 

ADDRESSES: Submit your comments, identified by Docket ID No. 

EPA-HQ-OAR-2008-0708, by one of the following methods:

 www.regulations.gov: Follow the on-line instructions for 

submitting comments.

 Email: a-and-r-docket@epa.gov.

 Fax: (202) 566-1741.

 Mail: Air and Radiation Docket and Information Center, 

Environmental Protection Agency, Mailcode: 6102T, 1200 

Pennsylvania Ave., NW, Washington, DC 20460. Please 

include a total of two copies. The EPA requests a 

separate copy also be sent to the contact person 
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identified below (see FOR FURTHER INFORMATION CONTACT). 

 Hand Delivery: Air and Radiation Docket and Information 

Center, U.S. EPA, Room B102, 1301 Constitution Avenue, 

NW, Washington, DC. Such deliveries are only accepted 

during the Docket’s normal hours of operation, and 

special arrangements should be made for deliveries of 

boxed information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR2008-0708. The EPA’s policy is that all comments received will 

be included in the public docket without change and may be made 

available on-line at www.regulations.gov, including any personal 

information provided, unless the comment includes information 

claimed to be Confidential Business Information (CBI) or other 

information whose disclosure is restricted by statute. Do not 

submit information that you consider to be CBI or otherwise 

protected through www.regulations.gov or email. The 

www.regulations.gov website is an “anonymous access” system, 

which means the EPA will not know your identity or contact 

information unless you provide it in the body of your comment.

If you send an email comment directly to the EPA without going 

through www.regulations.gov, your email address will be 

automatically captured and included as part of the comment that 

is placed in the public docket and made available on the 

Internet. If you submit an electronic comment, the EPA 
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recommends that you include your name and other contact 

information in the body of your comment and with any disk or CDROM you submit. If the EPA cannot read your comment due to 

technical difficulties and cannot contact you for clarification, 

the EPA may not be able to consider your comment. Electronic 

files should avoid the use of special characters, any form of 

encryption, and be free of any defects or viruses.

Public Meeting: If a public meeting is held, it will be held at 

the EPA’s campus located at 109 T.W. Alexander Drive in Research 

Triangle Park, NC or an alternate site nearby.

Docket: All documents in the docket are listed in the 

www.regulations.gov index. The EPA also relies on documents in 

Docket ID Nos. EPA-HQ-OAR-2002-0059, EPA-HQ-OAR-2005-0029, EPAHQ-OAR-2005-0030, and EPA-HQ-OAR-2010-0295, and incorporated

those dockets into the record for this action. Although listed 

in the index, some information is not publicly available, e.g., 

CBI or other information whose disclosure is restricted by 

statute. Certain other material, such as copyrighted material, 

will be publicly available only in hard copy. Publicly available 

docket materials are available either electronically in 

www.regulations.gov or in hard copy at the Air and Radiation 

Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW, 

Washington, DC. The Public Reading Room is open from 8:30 a.m. 

to 4:30 p.m., Monday through Friday, excluding legal holidays. 
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The telephone number for the Public Reading Room is (202) 566-

1744, and the telephone number for the Air Docket is (202) 566-

1742.

FOR FURTHER INFORMATION CONTACT: Ms. Melanie King, Energy 

Strategies Group, Sector Policies and Programs Division (D243-

01), Environmental Protection Agency, Research Triangle Park, 

North Carolina 27711; telephone number (919) 541-2469; facsimile 

number (919) 541-5450; email address king.melanie@epa.gov.

SUPPLEMENTARY INFORMATION: Organization of This Document. The 

following outline is provided to aid in locating information in 

the preamble. 

I. General Information

A. Executive Summary

B. Does this action apply to me?

C. What should I consider as I prepare my comments for the EPA?

II. Summary of Proposed Amendments

A. Total Hydrocarbon Compliance Demonstration Option

B. Emergency Demand Response/Peak Shaving

C. Non-Emergency Stationary SI RICE Greater than 500 HP Located 

at Area Sources

D. Stationary Agricultural RICE in San Joaquin Valley

E. Remote Areas of Alaska

F. Miscellaneous Corrections and Revisions

G. Compliance Date

III. Summary of Environmental, Energy and Economic Impacts 

A. What are the air quality impacts?

B. What are the cost impacts?

C. What are the benefits?

D. What are the non-air health, environmental and energy 

impacts?

IV. Solicitation of Public Comments and Participation 

V. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review and 

Executive Order 13563: Improving Regulation and Regulatory 

Review 

B. Paperwork Reduction Act
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C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act of 1995

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments

G. Executive Order 13045: Protection of Children from 

Environmental Health and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations that 

Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action

The purpose of this action is to propose amendments to the 

national emission standards for hazardous air pollutants 

(NESHAP) for stationary reciprocating internal combustion 

engines (RICE) under section 112 of the Clean Air Act (CAA).

This proposal was developed to address certain issues that have 

been raised by different stakeholders through lawsuits, several 

petitions for reconsideration of the 2010 RICE NESHAP amendments 

and other communications. This proposal also provides 

clarifications and corrects minor mistakes in the current RICE 

NESHAP and revises the new source performance standards (NSPS) 

for stationary engines, 40 CFR part 60, subparts IIII and JJJJ,

for consistency with the RICE NESHAP.

This action is conducted under the authority of section 112 

of the CAA, “Hazardous Air Pollutants,” (HAP) which requires the 
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EPA to establish NESHAP for the control of hazardous air 

pollutants (HAP) from both new and existing sources in regulated 

source categories.

2. Summary of the Major Provisions of the Regulatory Action

After promulgation of the 2010 RICE NESHAP amendments, the 

EPA received several petitions for reconsideration, legal 

challenges, and other communications raising issues of practical 

implementability, and certain factual information that had not 

been brought to the EPA’s attention during the rulemaking. The 

EPA has considered this information and believes that amendments 

to the rule to address certain of these issues are appropriate. 

Therefore, the EPA is proposing to amend 40 CFR part 63, subpart 

ZZZZ, NESHAP for Stationary RICE. The current regulation applies 

to owners and operators of existing and new stationary RICE at 

major and area sources of HAP emissions. The applicability of 

the rule remains the same and is not changed by this proposal. 

The EPA is also proposing to amend the NSPS for stationary 

engines to conform with certain of the amendments proposed for 

the NESHAP. 

The EPA proposes to add an alternative compliance 

demonstration option for stationary 4-stroke rich burn (4SRB)

spark ignition (SI) engines subject to a 76 percent or more 

formaldehyde reduction. Owners and operators of 4SRB engines 

would be permitted to demonstrate compliance with the 76 percent 
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formaldehyde reduction emission standard by testing total 

hydrocarbon (THC) emissions and showing that the engine is 

achieving at least a 30 percent reduction of THC emissions. The 

alternative compliance option would provide a less expensive and 

less complex, but equally effective, method for demonstrating 

compliance than testing for formaldehyde.

Certain stationary RICE are maintained in order to be able 

to respond to emergency power needs. The EPA proposes to allow

owners and operators of such stationary emergency RICE to 

operate their engines as part of an emergency demand response 

program within the 100 hours per year that is already permitted 

for maintenance and testing of the engines. The 100 hours per 

year allowance would ensure that a sufficient number of hours 

are permitted for engines to meet independent system operator 

(ISO) and regional transmission organization (RTO) tariffs and 

other requirements for participating in various emergency demand 

response programs and would assist in stabilizing the grid,

preventing electrical blackouts and supporting local electric 

system reliability. A temporary limited allowance that will 

expire on April 16, 2017 (the date by which full compliance with 

the NESHAP From Coal and Oil-Fired Electric Utility Steam 

Generating Units (77 FR 9304) is expected), is being proposed 

for stationary emergency engines located at area sources of HAP 

emissions to be used for up to 50 hours per year for any non-
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emergency purpose, including peak shaving. The 50 hours is part 

of the 100 hours per year total allowance for all types of 

emergency engine operation (except during emergencies where no 

other power is available, which is not restricted by the rule). 

The temporary allowance for peak shaving would give sources time 

to address reliability issues and develop solutions to 

reliability issues while facilities are coming into compliance 

with the National Emission Standards for Hazardous Air 

Pollutants From Coal and Oil-Fired Electric Utility Steam 

Generating Units, which were promulgated on February 16, 2012 

(77 FR 9304). 

The EPA proposes management practices for owners and 

operators of existing stationary 4-stroke SI engines above 500 

horsepower (HP) that are area sources of HAP emissions and where 

the engines are remote from human activity. A remote area is 

defined as either a Department of Transportation (DOT) Class 1 

pipeline location1, or, if the facility is not on a pipeline, if 

within a 0.25 mile radius of the facility there are 5 or less 

buildings intended for human occupancy. The 0.25 mile radius was 

chosen as the area would be similar to the area used for the DOT 

pipeline Class location. The EPA proposes that these sources be 

subject to management practices rather than numeric emission 

 

1 A Class 1 location is defined as an offshore area or any class 

location unit that has 10 or fewer buildings intended for human 

occupancy.
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limits and associated testing and monitoring. This would address 

reasonable concerns with accessibility, infrastructure, and 

staffing that stem from the remoteness of the engines and higher 

costs that would be associated with compliance with the existing 

requirements. The EPA proposes that existing stationary 4-stroke 

SI engines above 500 HP at area sources that are in populated 

areas (defined as not in DOT pipeline Class 1 areas, or if not 

on a pipeline, if within a 0.25 mile radius of the facility 

there are more than 5 buildings intended for human occupancy) be 

subject to an equipment standard that requires the installation 

of HAP-reducing aftertreatment. The EPA has the discretion to 

set an equipment standard as GACT for engines located at area 

sources of HAP. Sources would be required to test their engines 

to demonstrate compliance initially, perform catalyst activity 

check-ups, and either monitor the catalyst inlet temperature 

continuously or employ high temperature shutdown devices to 

protect the catalyst.

To address how certain existing compression ignition (CI) 

engines are currently regulated, the EPA proposes to specify 

that any existing certified CI engine above 300 HP at an area 

source of HAP emissions that was certified to meet the Tier 3 

engine standards and was installed before June 12, 2006, is in 

compliance with the NESHAP. This provision would create 

regulatory consistency between the same engines installed before 
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and after June 12, 2006. Engines at area sources of HAP for 

which construction commenced before June 12, 2006, are 

considered existing engines under the NESHAP. 

The EPA is proposing amendments to the requirements for 

existing stationary Tier 1 and Tier 2 certified CI engines 

located at area sources that are subject to state and locally 

enforceable requirements requiring replacement of the engine by

June 1, 2018. This is meant to deal with a specific concern 

regarding the interaction of the NESHAP with certain rules for 

agricultural engines in the San Joaquin Valley in California.

The EPA is proposing to allow these engines to meet management 

practices under the RICE NESHAP from the May 3, 2013 compliance 

date until January 1, 2015, or 12 years after installation date, 

but not later than June 1, 2018. This provision would deal with 

the issue of owners and operators having to install controls on 

their engines in order to meet the RICE NESHAP, and then having 

to replace their engines shortly thereafter due to state and 

local rules specifying the replacement of engines. Owners and 

operators will have additional time to replace their engines 

without having to install controls, but will be required to use 

management practices during that period.

The last major change the EPA proposes to make is to 

broaden the definition of remote area sources of Alaska in the 

RICE NESHAP. Currently, remote areas are those that are not on 
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the Federal Aid Highway System (FAHS). This change would permit 

existing stationary CI engines at other remote area sources in 

Alaska to meet management practices as opposed to emission 

standards likely necessitating aftertreatment. These remote 

areas have the same challenges as areas not on the FAHS, and 

complying with the current rule would similarly be prohibitively 

costly and potentially infeasible. In addition to area sources 

located in areas of Alaska that are not accessible by the FAHS 

being defined as remote and subject to management practices, the 

EPA also proposes that any stationary RICE in Alaska meeting all 

of the following conditions be subject to management practices:

(1) The only connection to the FAHS is through the Alaska 

Marine Highway System (AMHS), or the stationary RICE operation 

is within an isolated grid in Alaska that is not connected to 

the statewide electrical grid referred to as the Alaska Railbelt 

Grid, and

(2) At least 10 percent of the power generated by the 

stationary RICE on an annual basis is used for residential 

purposes, and

(3) The generating capacity of the area source is less than 

12 megawatts, or the stationary RICE is used exclusively for 

backup power for renewable energy and is used less than 500 hrs 

per year on a 10 year rolling average.

3. Costs and Benefits
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These proposed amendments would reduce the capital and 

annual costs of the original 2010 amendments by $287 million and 

$139 million, respectively. The EPA estimates that with the 

proposed amendments, the capital cost of the rule is $840 

million and the annual cost is $490 million ($2010).

These proposed amendments would also result in decreases to 

the emissions reductions estimated in 2013 from the original 

2010 RICE NESHAP amendments. The estimated reductions in 2013 

from the 2010 RICE NESHAP rulemaking with these proposed 

amendments are 2,800 tons per year (tpy) of HAP, 36,000 tpy of 

carbon monoxide (CO), 2,800 tpy of particulate matter (PM), 

9,600 tpy of nitrogen oxide (NOx), and 36,000 tpy of volatile 

organic compounds (VOC). The reductions that were estimated for 

the original 2010 RICE NESHAP amendments were 7,000 tpy of HAP, 

124,000 tpy of CO, 2,800 tpy of PM, 96,000 tpy of NOx, and 

58,000 tpy of VOC.

The EPA estimates the monetized co-benefits in 2013 of the 

original 2010 RICE NESHAP amendments with these proposed 

amendments incorporated to be $830 million to $2,100 million 

(2010 dollars) at a 3-percent discount rate and $740 million to 

$1,800 million (2010 dollars) at a 7-percent discount rate. The 

benefits that were estimated for the original 2010 RICE NESHAP 

amendments were $1,500 million to $3,600 million (2010 dollars) 
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at a 3-percent discount rate and $1,300 million to $3,200 

million (2010 dollars) at a 7-percent discount rate.

B. Does this action apply to me?

Regulated Entities. Categories and entities potentially 

regulated by this action include:

Category NAICS1 Examples of regulated entities

Any industry 

using a 

stationary 

internal 

combustion engine 

as defined in the

proposed 

amendments.

2211 Electric power generation, 

transmission, or distribution.

622110 Medical and surgical hospitals.

48621 Natural gas transmission.

211111 Crude petroleum and natural gas 

production.

211112 Natural gas liquids producers.

92811 National security.

1 North American Industry Classification System.

This table is not intended to be exhaustive, but rather provides 

a guide for readers regarding entities likely to be regulated by 

this action. To determine whether your engine is regulated by 

this action, you should examine the applicability criteria of 

this proposed rule. If you have any questions regarding the 

applicability of this action to a particular entity, consult the 

person listed in the preceding FOR FURTHER INFORMATION CONTACT

section.

C. What should I consider as I prepare my comments for the EPA?

1. Submitting CBI. Do not submit this information to the EPA 

through regulations.gov or email. Clearly mark the part or all 
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of the information that you claim to be CBI. For CBI information 

in a disk or CD ROM that you mail to the EPA, mark the outside 

of the disk or CD ROM as CBI and then identify electronically 

within the disk or CD ROM the specific information that is 

claimed as CBI. In addition to one complete version of the 

comment that includes information claimed as CBI, a copy of the 

comment that does not contain the information claimed as CBI 

must be submitted for inclusion in the public docket. 

Information so marked will not be disclosed except in accordance 

with procedures set forth in 40 CFR part 2. Send or deliver 

information identified as CBI to only the following address: Ms. 

Melanie King, c/o OAQPS Document Control Officer (Room C404-02), 

U.S. EPA, Research Triangle Park, NC 27711, Attention Docket ID 

No. EPA-HQ-OAR-2008-0708.

2. Tips for Preparing Your Comments. When submitting comments, 

remember to:

(a) Identify the rulemaking by docket number and other 

identifying information (subject heading, Federal Register date 

and page number).

(b) Follow directions. The EPA may ask you to respond to 

specific questions or organize comments by referencing a Code of 

Federal Regulations (CFR) part or section number.

(c) Explain why you agree or disagree; suggest alternatives 

and substitute language for your requested changes. 
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(d) Describe any assumptions and provide any technical 

information and/or data that you used.

(e) If you estimate potential costs or burdens, explain how 

you arrived at your estimate in sufficient detail to allow for 

it to be reproduced.

(f) Provide specific examples to illustrate your concerns, 

and suggest alternatives.

(g) Explain your views as clearly as possible, avoiding the 

use of profanity or personal threats.

(h) Make sure to submit your comments by the comment period 

deadline identified.

Docket. The docket number for this proposed rule is Docket ID 

No. EPA-HQ-OAR-2008-0708.

World Wide Web (WWW). In addition to being available in the 

docket, an electronic copy of this proposed rule will be posted 

on the WWW through the Technology Transfer Network Website (TTN 

Web). Following signature, the EPA will post a copy of this 

proposed rule on the TTN’s policy and guidance page for newly 

proposed or promulgated rules at http://www.epa.gov/ttn/oarpg. 

The TTN provides information and technology exchange in various 

areas of air pollution control. 

II. Summary of Proposed Amendments

This action proposes amendments to the NESHAP for RICE in 

40 CFR part 63, subpart ZZZZ. This action also proposes 
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amendments to the NSPS for stationary engines in 40 CFR part 60, 

subparts IIII and JJJJ. The NESHAP for stationary RICE to 

regulate emissions of HAP was developed in several stages. The 

EPA initially addressed stationary RICE greater than 500 HP 

located at major sources of HAP emissions in 2004 (69 FR 33473). 

The EPA addressed new stationary RICE less than or equal to 500 

HP located at major sources and new stationary RICE located at 

area sources in 2008 (73 FR 3568). Most recently, requirements 

for existing stationary RICE less than or equal to 500 HP 

located at major sources and existing stationary RICE located at 

area sources were finalized in 2010 (75 FR 9648 and 75 FR 

51570). 

The EPA is proposing to address a number of issues that 

have been raised by different stakeholders through lawsuits,

several petitions for reconsideration of the 2010 RICE NESHAP 

amendments, and other communications. The EPA is also proposing 

to revise 40 CFR part 60, subparts IIII and JJJJ for consistency 

with the RICE NESHAP and to make minor corrections and 

clarifications. The following sections present the issues that 

the EPA is addressing in this action, background information as 

to why these issues are causing concern among affected 

stakeholders, and how the EPA proposes to resolve the issues.

A. Total Hydrocarbon Compliance Demonstration Option

1. Background
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Currently, SI 4SRB non-emergency engines greater than 500 

HP located at major sources and existing SI 4SRB non-emergency 

engines greater than 500 HP located at area sources have the 

option of meeting either a formaldehyde percent reduction or a 

formaldehyde concentration standard. Formaldehyde was 

established in the original 2004 RICE NESHAP as an appropriate 

surrogate for HAP emissions from 4SRB engines based on industry 

test data available at that time. Based on testing of stationary 

lean burn engines conducted at Colorado State University (CSU),

the EPA was able to establish CO as a surrogate for HAP for lean 

burn engines. Rich burn engines were not tested at CSU and the 

data the EPA had available at the time that were used to set the 

standards for rich burn engines did not support the same 

relationship between CO and HAP reductions for rich burn 

engines. Therefore, the EPA was unable to establish CO as a 

surrogate for HAP emissions for rich burn engines and the 

emission standard for rich burn engines was specified in terms 

of formaldehyde, the hazardous air pollutant emitted in the 

largest quantity from stationary engines. 

The EPA has previously acknowledged that it is 

significantly more expensive and difficult to test for 

formaldehyde than for CO, but has been unable in the past to 

support the same flexibility for rich burn engines as is 

currently in the rule for lean burn engines with the option to 
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meet the standards in terms of either formaldehyde or CO. For 

these reasons, and expecting that new data for rich burn engines 

may become available in the future for the EPA to review and 

reassess possible surrogates for HAP, the EPA requested comment 

on this issue when proposing NESHAP for stationary existing 

engines less than or equal to 500 HP at major sources and all 

stationary existing engines at area sources in 2009 (74 FR 

9698). Specifically, the EPA solicited comment on whether it 

would be appropriate to include an alternative standard in terms 

of VOC and asked that commenters submit data supporting the 

relationship between HAP and VOC. Comments the EPA received back 

on the proposed rule asked that the formaldehyde standards for 

rich burn engines be replaced with emission standards for THC.

The EPA determined at the time that it was not appropriate to 

adopt an alternative standard in terms of THC (or VOC) for rich 

burn engines and discussed the reasons why in the 2010 responses 

to comments.

2 Compliance with the formaldehyde standard in the 

rule is, therefore, currently demonstrated by initial and 

continuous performance testing for formaldehyde. 

 

2 Memorandum from Melanie King, EPA Energy Strategies Group to 

EPA Docket EPA-HQ-OAR-2008-0708. Response to Public Comments on 

Proposed National Emission Standards for Hazardous Air 

Pollutants for Existing Stationary Reciprocating Internal 

Combustion Engines Located at Area Sources of Hazardous Air 

Pollutant Emissions or Have a Site Rating Less Than or Equal to 

500 Brake HP Located at Major Sources of Hazardous Air Pollutant 

Emissions. August 10, 2010. EPA-HQ-OAR-2008-0708-0557.
Page 20 of 200

On October 19, 2010, engine manufacturer Dresser-Waukesha

submitted a petition for reconsideration of the formaldehyde

requirements. The EPA granted the petition for reconsideration 

on January 5, 2011. (In addition, on November 3, 2010, the 

Engine Manufacturers Association submitted a petition for 

judicial review of these requirements.) In the petition for 

reconsideration, Dresser-Waukesha argued that formaldehyde is 

difficult and costly to measure. The petition requested that the 

HAP surrogate for 4SRB engines should be THC rather than 

formaldehyde. Dresser-Waukesha submitted data from testing it 

conducted illustrating that THC reduction across the catalyst is 

an appropriate surrogate for HAP reduction across the catalyst.3

According to the petitioner, testing for THC is easier and less 

costly and would substantially reduce the burden of the rule for 

owners and operators of these engines. Testing for formaldehyde 

emissions could cost more than double that of testing for THC

emissions and on a nationwide basis the EPA estimates that 

replacing formaldehyde testing with THC testing would result in 

substantial compliance cost savings annually while achieving the 

same reduction in HAP emissions.

The EPA has reviewed the data submitted by DresserWaukesha. The data provided indicate that a strong relationship 

 

3Letter from Dresser-Waukesha to Melanie King. Follow-up to 

November 18, 2010 Teleconference. December 6, 2010. EPA-HQ-OAR2008-0708-0662.
Page 21 of 200

exists between percentage reductions of THC and percentage 

reductions of formaldehyde (the surrogate for HAP emissions in 

the NESHAP) on rich burn engines using non-selective catalytic 

reduction (NSCR). Data analyzed by the EPA indicate that if the 

NSCR is reducing THC by at least 30 percent from 4SRB engines,

formaldehyde emissions are guaranteed to be reduced by at least 

76 percent, which is the percentage reduction required for the 

relevant engines. Indeed, the percentage reduction of 

formaldehyde is invariably well above the 76 percent level, and 

is usually above 90 percent. Therefore, the EPA agrees with the 

petitioner that for SI 4SRB engines using NSCR and meeting the 

NESHAP by showing a percentage reduction of HAP, it would be 

appropriate to allow sources to demonstrate compliance with the 

NESHAP by showing a THC reduction of at least 30 percent.

Including an optional THC compliance demonstration option would 

reduce the cost of compliance significantly while continuing to 

achieve the same level of HAP emission reduction because the 

emission standards would remain the same. Consequently, the EPA 

is proposing amendments to allow owners and operators of certain 

stationary 4SRB engines (i.e., the ones currently subject to a 

formaldehyde percent reduction requirement) to show compliance 

with an optional THC compliance demonstration option. The 

specific amendments the EPA is proposing are presented below.

2. Proposed Amendments
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The EPA is proposing to add an alternative method of

demonstrating compliance with the NESHAP for stationary 4SRB 

non-emergency engines greater than 500 HP that are located at 

major sources of HAP emissions and for existing stationary 4SRB 

non-emergency engines greater than 500 HP that are located at 

area sources of HAP emissions that choose to meet the 

formaldehyde percent reduction requirement of 76 percent or 

more.

Based on the arguments and evidence presented in the 

petition discussed above, the EPA is proposing to add a 

compliance demonstration option for stationary 4SRB engines 

meeting a 76 percent or more formaldehyde reduction. The 

compliance demonstration option would be an alternative to the 

existing method of demonstrating compliance with the 

formaldehyde percent reduction standard, which is to test 

engines for formaldehyde. The alternative for owners and 

operators of 4SRB engines meeting a 76 percent or more 

formaldehyde reduction would be to test their engines for THC 

showing that the engine is achieving at least a 30 percent 

reduction of THC emissions. 

Under the proposed amendments, existing and new stationary 

4SRB engines greater than 500 HP and located at major sources 

would still be required to reduce formaldehyde emissions by 76 

percent or more or limit the concentration of formaldehyde in 
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the stationary RICE exhaust to 350 parts per billion by volume, 

dry basis or less at 15 percent oxygen (O2). However, owners and 

operators choosing to meet the formaldehyde concentration limit 

would not have the THC demonstration compliance option, because 

EPA could not verify a clear relationship between concentrations 

of THC and concentrations of formaldehyde in exhaust from these 

SI 4SRB engines. For the reasons discussed in section II.C.1 of 

this preamble, the EPA is proposing that existing stationary 

4SRB non-emergency engines greater than 500 HP located at area 

sources located in populated areas be subject to an equipment 

standard and required to install a catalyst. These engines would 

be subject to testing to demonstrate initially and on an ongoing 

basis that the catalyst is reducing CO by 75 percent or more, or 

alternatively that THC emissions are being reduced by 30 percent 

or more. 

Owners and operators of existing stationary 4SRB engines 

less than or equal to 500 HP who are required to limit the 

concentration of formaldehyde in the stationary RICE exhaust to 

10.3 parts per million by volume, dry basis (ppmvd) or less at 

15 percent O2 do not have the option to demonstrate compliance 

using THC and must continue to demonstrate compliance by testing 

for formaldehyde following the methods and procedures specified 

in the rule.
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Owners and operators opting to use the THC compliance 

demonstration method must demonstrate compliance by showing that 

the average reduction of THC is equal to or greater than 30 

percent. Owners and operators of 4SRB stationary RICE complying 

with the requirement to reduce formaldehyde emissions and 

demonstrating compliance by using the THC compliance 

demonstration option must conduct performance testing using 

Method 25A of 40 CFR part 60, appendix A – Determination of 

Total Gaseous Organic Concentration Using a Flame Ionization 

Analyzer. Measurements of THC at the inlet and the outlet of the 

NSCR must be on a dry basis and corrected to 15 percent O2 or 

equivalent carbon dioxide content. To correct to 15 percent O2, 

dry basis, owners and operators must measure oxygen using Method 

3, 3A or 3B of 40 CFR part 60, appendix A, or ASTM Method D6522-

00 (2005) and measure moisture using Method 4 of 40 CFR part 60, 

appendix A, or Test Method 320 of 40 CFR part 63, appendix A, or 

ASTM D6348-03. Because owners and operators are complying with a 

percent reduction requirement, the method used must be suitable 

for the entire range of emissions since pre and post-catalyst 

emissions must be measured. Method 25A is capable of measuring 

emissions down to 5 ppmv and is, therefore, an appropriate 

method for measuring THC emissions for compliance demonstration 

purposes. The EPA is allowing sources the option to meet a 

minimum THC percent reduction of 30 percent by using Method 25A 
Page 25 of 200

of 40 CFR part 60, appendix A to demonstrate compliance with the 

formaldehyde percent reduction in 40 CFR part 63, subpart ZZZZ.

B. Emergency Demand Response/Peak Shaving

1. Background

This action also proposes to amend provisions in the RICE 

NESHAP that currently allow owners and operators to operate 

stationary emergency engines for up to 15 hours per year as part 

of a demand response program if the RTO or equivalent balancing 

authority and transmission operator have 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 final rule did not allow emergency engines to be used for 

purposes of peak shaving or other non-emergency purposes as part 

of a financial arrangement. These provisions were included in 

the RICE NESHAP when requirements for existing stationary CI 

engines were finalized on March 3, 2010 (75 FR 9648). Following 

the completion of that portion of the rule, the EPA received 

three main petitions for reconsideration. One petition was from 

CPower, Inc., EnergyConnect, Inc., EnerNOC, Inc., and 

Innoventive Power, LLC. (EnerNOC et al.)(EPA-HQ-OAR-2008-0708-

0404). Another petition was received from the Delaware 

Department of Natural Resources and Environmental Control (DE 

DNREC) (EPA-HQ-OAR-2008-0708-0400). The third petition was from 
Page 26 of 200

the National Rural Electric Cooperative Association (NRECA) 

(OAR-2008-0708-0580). In addition to these main petitions the 

EPA received a substantial number of letters from others in the 

electric generation industry.

The petition from EnerNOC, et al., asked that EPA increase 

the period of time permitted for emergency demand response 

operation in the rule to 60 hours per year, or the minimum 

number of hours required by the emergency demand response 

program. By contrast, the DE DNREC petition asked EPA to 

reconsider the emergency demand response provision because of 

the adverse effects that it believes would result from increased 

emissions from these engines. The petition from NRECA requested 

that the EPA eliminate the restriction on the use of stationary 

emergency engines for demand response purposes. The EPA granted 

the petitions from EnerNOC, et al., DE DNREC and NRECA, and 

issued a notice on December 7, 2010 (75 FR 75937), requesting 

comments on whether to amend the 15 hours per year limitation on 

the operation of stationary emergency RICE participating in 

emergency demand response programs. 

The EPA received more than 120 comments from a number of 

different entities including various state agencies, utilities, 

electric cooperatives and industry organizations. Many 

commenters expressed that 15 hours per year is not sufficient to 

meet current emergency demand response requirements for 
Page 27 of 200

participation. For example, several emergency demand response 

programs have ISO tariff requirements greater than 15 hours per 

year, including the Electric Reliability Council of Texas 

emergency demand response program, which has a tariff 

requirement of 24 hours per year; the Pennsylvania Jersey 

Maryland (“PJM”) Interconnection, known as the Emergency Load 

Response Program, which has a tariff requirement of 60 hours per 

year; and the ISO New England (“ISO-NE”), which forecasts that 

backup resources would be expected for 55 hours over a 12-month 

period. Tariff requirements are developed to specify the 

mandatory time load resources (engines) must be willing and able 

to operate if the units are enrolled in the program. Conversely, 

some commenters urged the EPA to allow stationary emergency 

engines to only operate during true emergencies or when voltage 

or frequency varies beyond specified parameters.

Based on the EPA’s review of the petitions and comments 

that the EPA has received, the EPA has found it appropriate to 

propose to amend the current rule to increase the allowance for

stationary emergency engine participation in emergency demand 

response programs to up to 100 hours per year, which would be 

included as part of the pre-existing allowance of 100 hours for 

owners of emergency engines to test and maintain their emergency 

engines. The EPA believes that the emergency demand response 

programs that exist across the country are important programs 
Page 28 of 200

that protect the reliability and stability of the national 

electric service grid. Allowing stationary emergency engines to 

operate as part of emergency demand response programs can help 

prevent grid failure or blackouts, by allowing these engines to 

be used in circumstances of grid instability prior to the 

occurrence of blackouts. Preventing stationary emergency engines 

from being able to qualify and participate in emergency demand 

response programs without having to apply aftertreatment could 

force owners and operators to leave their engines out of these 

programs, which will impair the ability of ISOs and RTOs to use

these relatively small, quick-starting and reliable sources of 

energy to protect the reliability of their systems. The EPA does 

not wish to potentially jeopardize electrical reliability or 

create a disincentive for stationary emergency engines to 

participate in these programs. The circumstances during which 

the EPA would allow stationary emergency engines to operate for 

emergency demand response purposes include periods during which 

the regional transmission authority or equivalent balancing 

authority and transmission operator has declared an Energy 

Emergency Alert Level 2 (EEA Level 2) as defined in the North 

American Electric Reliability Corporation Reliability Standard 

EOP-002-3, Capacity and Energy Emergency, plus during periods 

where there is a deviation of voltage or frequency of 5 percent 

or more below standard voltage or frequency. During EEA Level 2 
Page 29 of 200

alerts there is insufficient energy supply and a true potential 

for electrical blackouts. System operators must call on all 

available resources during EEA Level 2 alerts in order to 

stabilize the grid to prevent failure. Therefore, this situation 

is a good indicator of severe instability on the system. 

Consistent normal voltage provided by the utility is often 

called power quality and is an important factor in local 

electric system reliability. Reliability of the system requires 

electricity being provided at a normal expected voltage. The 

American National Standards Institute standard C84.1-1989 

defines the maximum allowable voltage sag at below 5 percent. On 

the local distribution level local voltage levels are therefore 

important and a 5 percent or more change in the normal voltage 

or frequency is substantial and an indication that additional 

resources are needed to ensure local distribution system 

reliability. This situation would be indicative of severe 

instability on the system. The EPA has revised the language 

identifying the emergency conditions that currently appears at 

40 CFR 63.6640(f) because that language is not as specific as 

the newly proposed language. The EPA believes that the newly 

proposed language, along with the preexisting language in the 

definition of emergency engine describing non-demand response 

emergency situations, will address all emergency events, 

including all those that would be recognized solely by the local 
Page 30 of 200

system operators, such as local weather events. The EPA requests 

comments on the scope of the new language.

Emergency demand response programs rely on agreements under 

which owners of engine agree to make their engines available to 

be called upon for a specific number of hours per year, as 

required by the relevant ISO or RTO tariff, under specified 

circumstances considered to indicate emergencies. In order to be 

enrolled in an emergency demand response program, participants 

must qualify their engines and must be able to use their 

emergency engines for the number of hours the program requires. 

Engines are not generally called upon for the maximum hours 

required by the tariffs. However, even though the engine may not 

be called at all or may run for fewer hours than the program 

requires it to be available in a particular year, the engine 

must still be available for those theoretical number of hours in 

order to join the program. Demand response contracts require 

more hours than the 15 hours per year that is currently in the 

regulations, and the commenters state that the 15 hours per year 

is not a sufficient amount of time to ensure the reliability of 

the program; some programs require up to 60 hours per year, as 

discussed earlier in this preamble. For these reasons, the EPA 

believes it is appropriate to allow additional hours for 

emergency demand response operation in order for such programs 

to be accessible to stationary emergency engines. Consequently, 
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the EPA is proposing amendments to the rule to increase the 

limitation on emergency demand response operation to 100 hours

per year for stationary emergency engines. It is expected that 

owners and operators of stationary emergency engines that seek 

to qualify their units as demand resources would with the 

proposed increase to 100 hours per year be able to meet the 

operational and qualification requirements of the different ISOs 

and RTOs in the country. 

As stated, stationary emergency engines that participate in 

demand response programs may not be called upon at all, but must 

nonetheless be available to operate for the required amount 

stipulated by the specific program. The purpose of the limited 

allowance for emergency demand response is to respond to 

emergencies, and the EPA is persuaded by the information that 

has been submitted that 15 hours per year is an insufficient 

amount of time to allow for emergency demand response needs, 

given past experience. The EPA believes 100 hours per year is 

sufficient to cover any potential demand response operation as 

well as the required maintenance and testing that is also 

included within the 100 hours of operation. 

The EPA has previously determined that stationary emergency 

engines typically operate well below 50 hours per year and more 

commonly about 1 to 2 hours per month. A survey conducted by the 

California Air Resources Board (CARB) indicated the average 
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yearly operation for emergency diesel engines was 31 hours over 

a period of 3 years. The majority of those hours were for the 

purpose of maintenance and testing; less than 5 hours was for 

interruptible service contracts, and the remaining amount for 

emergency/standby operation (EPA-HQ-OAR-2005-0029-0011). Data 

from demand response programs in ISO-NE and PJM territories show 

that backup generation was dispatched for less than 30 hours 

during the summers of 2008, 2009 and 2010.4

However, again, emergency units must be available to 

operate more than that in most cases to qualify for demand 

response programs. For instance, PJM requires a minimum ISO 

tariff of 60 hours per year of engine availability for program 

participation. Consequently, in order to ensure that a 

sufficient amount of operating time is available for maintenance 

and readiness testing, and for demand response operation, the 

EPA is proposing 100 hours of operation. A number of commenters 

requested that an allowance of 100 hours per year be allowed in 

order to provide adequate hours consistent with minimum required 

hours that customers must be available to operate and to address 

local distribution system emergencies. For instance, in Hawaii, 

the emergency demand response program operated by the Hawaiian 

Electric Company requires that emergency engines be able to 

 

4 Memorandum from Stacy Angel, Synapse Energy Economics, Inc. to 

Doug Hurley, Synapse Energy Economics. Sample Revenue for a 1 MW 

Backup Generation Unit. June 27, 2011.
Page 33 of 200

operate for 100 hours per year in the event of an emergency in 

order to participate in the program. In order to provide a 

sufficient amount of time to cover annual maintenance and 

testing, which is typically more than 20 hours per year 

according to the survey conducted by CARB (see EPA-HQ-OAR-2005-

0029-0011), plus to cover hours necessary for qualifying for 

emergency demand response programs or local distribution system 

emergencies, EPA believes an allowance of 100 hours per year 

would be appropriate for these activities. Taking into account 

that there may be situations where annual maintenance and 

testing could exceed the typical 1 to 2 hours per month and 

accounting for other emergency demand response programs that 

require more than 60 hours per year for program participation 

(e.g., the Hawaiian Electric Company), the EPA believes that 100 

hours per year is appropriate for emergency demand response plus 

maintenance and testing. 

The proposed amendment to the rule would mean that 

stationary emergency engines could operate for a total of 100 

hours per year for emergency demand response operation as part 

of the 100 hours already permitted for maintenance and readiness 

testing while maintaining their status as emergency units, 

rather than non-emergency units, and continue to meet the 

requirements that apply to emergency engines.
Page 34 of 200

On the issue of peak shaving and non-emergency demand 

response, the EPA is proposing to include a temporary limited 

allowance for peak shaving and other types of non-emergency use

as part of a financial arrangement for existing stationary 

emergency engines at area sources of HAP, if the peak shaving is 

done as part of a peak shaving (or load management) program with 

the local distribution system operator. The power generated 

under this allowance can only be used at the facility or towards 

the local system. 

The EPA has determined that it is appropriate to include 

the option for existing stationary emergency engines at area 

sources to operate for a small number (50) of hours per year for 

any non-emergency reason and not be penalized or considered a 

non-emergency engine and subsequently required to install 

aftertreatment that could be prohibitively costly for these 

sources in the near term. The EPA is proposing that the 50-hour

allowance for peak shaving for emergency engines at area sources 

be allowed for a limited period of time, but then removed after 

April 16, 2017. The peak shaving would also be limited to 

operation as part of a peak shaving (load management program)

with the local distribution system operator. Owners would still 

have the pre-existing 50 hours per year allowance for nonemergency operation after April 16, 2017, but those 50 hours 

could no longer be used for peak shaving. The temporary 
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allowance for peak shaving would give sources an additional 

resource for maintaining reliability while facilities are coming 

into compliance with the NESHAP From Coal and Oil-Fired Electric 

Utility Steam Generating Units (77 FR 9304). While the EPA does 

not expect the NESHAP From Coal and Oil-Fired Electric Utility 

Steam Generating Units to cause regional reliability problems, 

this limited allowance would allow the owners and operators of 

these engines more flexibility to run reliability critical units 

in order to minimize potential grid-related interruptions as 

coal- and oil-fired baseload power plants may be temporarily 

shut down to install emission controls to comply with the NESHAP

From Coal and Oil-Fired Electric Utility Steam Generating Units.

Including this allowance is important for small electric 

cooperatives and other entities located at area sources that use 

these engines to maintain voltage and electric reliability. Many 

rural electric cooperatives enter agreements with owners of 

small emergency engines and rely on the engines to reduce demand 

on the central power supply during periods of high demand, which 

reduces the cost of power during periods of high demand for the 

members of the cooperative. Commenters promoting the continued 

use of peak shaving programs said that maintaining the cost of 

power as low as possible is important across the country, but is 

particularly of significant importance to rural electric 

cooperatives that, according to the commenter, service customers 
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in the most economically depressed areas of the country, where 

options are the most limited. The commenters argued that if 

small emergency engines would no longer be permitted to operate 

for peak shaving purposes without having to be reclassified as 

non-emergency engines and subsequently subject to costly 

emissions controls, owners could no longer afford to participate 

in such programs. Cooperatives argued that this would lead to 

increased costs that would ultimately be passed along to the 

customers. Commenters also maintained that keeping peak shaving 

programs would not lead to additional public health risks or 

emissions because the operation for peak shaving is minimal. If 

peak shaving is not allowed under the rule, commenters said that 

this would lead to an increase in central power station capacity 

and possibly more transmission and distribution line capacity to 

accommodate the increase in demand resulting from eliminating 

small emergency engines from being used. This could lead to a 

larger impact on the environment and public health than allowing 

a small number of hours for peak shaving purposes. Certain small 

and remote facilities also rely on financial programs to 

generate additional income in order to maintain their engines 

and stay in operation. The additional funds can be essential for 

many smaller facilities and operations. Providing a limited 

allowance for peak shaving and non-emergency demand response 

could generate sufficient income to prevent small facilities and 
Page 37 of 200

owners from ceasing operation where these engines are in 

service. In order to further limit the operation of these 

engines to small, remote facilities, the EPA is proposing that 

the power generated under this allowance can only be used at the 

facility or towards the local system. In addition, while the EPA 

is proposing this allowance until the end of April 16, 2017, the 

EPA does not believe it is appropriate to continue the program 

beyond that time. Generators receive considerable compensation 

for their availability in peak shaving programs and the EPA 

believes that it is not appropriate to allow these engines to 

continue receiving compensation for this non-emergency use 

beyond 2017 without having to reduce their emissions. The 

generators must by that time decide whether to restrict their 

use to emergency or limited non-compensated non-emergency use or 

to reduce the emissions from their engines. The EPA also 

encourages engine owners and operators, as well as larger system 

planners, to consider the use of alternative peak shaving 

options, such as load curtailments, lower emitting distributed 

generation, combined heat and power, and reduced line losses on 

the electricity grid. 

The previous estimate of emissions from stationary 

emergency engines is not expected to change due to this proposed 

limited allowance. To estimate emissions from stationary 

emergency engines, the EPA has previously estimated that 
Page 38 of 200

emergency engines would on average operate for 50 hours per 

year. There is a wide range in how much these engines operate 

(some well below 50 hours per year), but on average and to be 

conservative, the EPA believes that 50 hours per year is still 

representative and consequently the environmental impact the EPA 

has calculated previously remains appropriate. In consideration 

of all these issues, the EPA is proposing amendments to the rule 

to provide a limited allowance for peak shaving for existing 

stationary emergency engines at area sources of HAP. The 

specific amendments the EPA is proposing are discussed below.

2. Proposed Amendments

a. Emergency Demand Response. Based on the discussion in section 

II.B.1 of this preamble, the EPA is proposing to revise the 

current provisions for stationary engines used for emergency 

demand response operation. The provisions the EPA is proposing 

to amend are in §§63.6640(f) and 63.6675 of 40 CFR part 63, 

subpart ZZZZ. Currently, §63.6640(f)(1)(iii) allows a maximum of 

15 hours per year to be spent towards demand response operation 

under certain qualifying conditions. Also, §63.6640(f)(1)(ii) 

currently includes an allowance of 100 hours per year for 

purposes of maintenance checks and readiness testing. The EPA is 

proposing that owners and operators of stationary emergency RICE 

be permitted to operate their engines as part of an emergency

demand response program within the 100 hours per year that is 
Page 39 of 200

permitted for maintenance and testing in §63.6640(f)(1)(ii). 

Owners and operators of stationary emergency engines can operate 

for emergency demand response during periods in which the 

regional transmission authority or equivalent balancing 

authority and transmission operator has declared an EEA Level 2 

as defined in the North American Electric Reliability 

Corporation Reliability Standard EOP-002-3, Capacity and Energy 

Emergency and during periods where there is a deviation of 

voltage or frequency of 5 percent or greater below standard 

voltage or frequency. The hours spent for emergency demand 

response operation are added to the hours spent for maintenance 

and testing purposes and counted towards the 100 hours per year. 

If the total time spent for demand response operation and 

maintenance and testing exceeds 100 hours per year the engine 

will not be considered an emergency engine under this subpart 

and will need to meet all requirements for non-emergency 

engines. The EPA is recognizing that these engines may be called 

to operate not only by the regional transmission operator or 

equivalent to maintain the reliability of the bulk power system, 

but also by the local transmission and distribution system 

operators to support the local power systems.

For stationary emergency engines above 500 HP that were 

installed prior to June 12, 2006, there is currently no 

emergency demand response allowance and there is no time limit 
Page 40 of 200

on the use of emergency engines for routine testing and 

maintenance in §63.6640(f)(2)(ii). Those engines were not the 

focus of the 2010 RICE NESHAP amendments; therefore, the EPA did 

not make any changes to the requirements for those engines as 

part of the 2010 amendments. For consistency, the EPA is now 

also proposing that owners and operators of stationary emergency 

engines installed prior to June 12, 2006, be permitted to 

operate their engines as part of a demand response program as 

well for a total of 100 hours per year, including time spent for 

maintenance and testing.

The EPA is also proposing to amend the NSPS for stationary 

CI and SI engines in 40 CFR part 60, subparts IIII and JJJJ, 

respectively, to provide the same allowance for stationary 

emergency engines for emergency demand response operation as for 

engines subject to the RICE NESHAP. The NSPS regulations 

currently do not include such an allowance for emergency demand 

response operation. For the reasons discussed in section II.B of 

this preamble as to why the EPA finds it appropriate to allow 

stationary emergency engines to participate in emergency demand 

response programs and remain being considered emergency units, 

and for consistency across engine regulations, the EPA is 

proposing to add an emergency demand response allowance under 

the NSPS regulations. Consequently, the EPA is proposing to 

revise the existing language in §§60.4211(f) and 60.4219 of 40 
Page 41 of 200

CFR part 60, subpart IIII, and §§60.4243(d) and 60.4248 of 40 

CFR part 60, subpart JJJJ, to specify that emergency engines may 

participate in demand response programs for up to 100 hours per 

year, including hours spent towards maintenance and testing of 

the emergency engines.

b. Peak Shaving and other Non-emergency Use as Part of a 

Financial Arrangement. In addition to the changes the EPA is 

proposing related to emergency demand response operation, the 

EPA is also including a further provision for owners and 

operators of existing stationary emergency RICE located at area 

sources for the reasons discussed in section II.B.1 of this 

preamble. Paragraph §63.6640(f) currently allows owners and 

operators of emergency stationary RICE to operate their engine 

for 50 hours per year in non-emergency situations. As currently 

written, 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 of certain emergency engines 

may operate the engine for a maximum of 15 hours per year as 

part of an emergency demand response program. As discussed, the 

15 hours per year allowance for emergency engines to participate 

in emergency demand response programs is being increased to 100 

hours per year, but will also include hours spent towards 
Page 42 of 200

maintaining and conducting readiness testing of the emergency 

engines. However, additionally, the EPA is also proposing that 

stationary emergency engines located at area sources be 

permitted to apply the 50 hours per year that is currently 

allowed under §63.6640(f) for non-emergency operation towards 

any non-emergency operation, including operation as part of a 

financial agreement with another entity. The peak shaving 

allowance would expire in 2017. The EPA is specifying that the 

power can only be used at the facility or towards the local 

system, and the engine can only be operated for peak shaving as 

part of a program with the local distribution system operator.

The EPA is also clarifying that an engine that exceeds the 

calendar year limitations on non-emergency operation, including 

emergency demand response or peak shaving, will be considered a 

non-emergency engine and subject to the requirements for nonemergency engines for the remaining life of the engine.

C. Non-Emergency Stationary SI RICE Greater than 500 HP Located 

at Area Sources

1. Background

The EPA is also proposing to amend the requirements that 

apply to existing stationary non-emergency 4 stroke SI RICE 

greater than 500 HP located at area sources of HAP emissions, 

which are generally natural gas fired engines. Currently, the 

RICE NESHAP requires owners and operators of such engines to 1) 
Page 43 of 200

either meet a CO concentration limit of 47 parts ppmvd at 15

percent O2 or reduce emissions of CO by 93 percent or more, if 

the engines are 4SLB; and 2) to meet a formaldehyde 

concentration limit of 2.7 ppmvd at 15 percent O2 or reduce 

formaldehyde emissions by 76 percent or more, if the engines are 

4SRB. In both cases, the EPA expects that the standards would be 

met using aftertreatment; oxidation catalysts for 4SLB engines 

and NSCR for 4SRB engines. In addition to these emission 

requirements, owners and operators of existing stationary 4-

stroke engines greater than 500 HP at area sources are also 

subject to monitoring, testing, recordkeeping and reporting 

requirements. 

After the final requirements for existing stationary SI 

engines greater than 500 HP at area sources were published on 

August 20, 2010 (75 FR 51570), the EPA received petitions from 

Exterran (EPA-HQ-OAR-2008-0708-0581), the American Petroleum 

Institute (EPA-HQ-OAR-2008-0708-0582), the Interstate Natural 

Gas Association of America (EPA-HQ-OAR-2008-0708-0584), and the 

Gas Processors Association (EPA-HQ-OAR-2008-0708-0587) 

requesting that the EPA reconsider the requirements of the final 

rule. The petitioners expressed many similar concerns. As 

relevant to this rulemaking, petitioners stated that the EPA did 

not take into account the difference in population density and 

subsequently did not consider the difference in health impacts 
Page 44 of 200

in remote versus more heavily populated locations. In the 

petitioners’ opinion, there should be less concern about engines 

that are located farther away from people; the petitioners

believed that the EPA has substantial latitude in requiring less 

stringent standards for owners and operators of stationary 

engines in remote areas.

While the EPA does not share all of the views of the 

petitioners regarding the difference between engines based on 

their location, the EPA does believe that it is reasonable to 

create a subcategory of existing stationary SI 4SLB and 4SRB 

engines above 500 HP located in areas remote from human 

activity. Engines located in remote areas that are not close to 

significant human activity may be difficult to access, may not 

have electricity or communications, and may be unmanned most of 

the time. The costs of the emission controls, testing, and 

continuous monitoring requirements may be unreasonable when 

compared to the HAP emission reductions that would be achieved, 

considering that the engines are in sparsely populated areas.

The EPA believes that establishing a subcategory for SI engines

at area sources of HAP located in sparsely populated areas

accomplishes the agency’s goals and is adequate in protecting 

public health.

The EPA is proposing to subcategorize sparsely populated 

engines using criteria based on the existing DOT classification 
Page 45 of 200

system for natural gas pipelines. This system classifies

locations based on their distance to natural gas pipelines 

covered by the Pipeline and Hazardous Materials Safety 

Administration safety regulations. The DOT system defines a 

class location unit as an onshore area that extends 220 yards or 

200 meters on either side of the centerline of any continuous 1-

mile (1.6 kilometers) length of natural gas pipeline. The DOT 

approach further classifies pipeline locations into Class 1 

through Class 4 locations based on the number of buildings 

intended for human occupancy. A Class 1 location is defined as 

an offshore area or any class location unit that has 10 or fewer 

buildings intended for human occupancy. The DOT classification 

system also has special provisions for locations that lie within 

100 yards (91 meters) of either a building or a small, welldefined outside area (such as a playground, recreation area, 

outdoor theater, or other place of public assembly) that is 

occupied by 20 or more persons on at least 5 days a week for 10 

weeks in any 12-month period. To be considered remote under this 

proposal, a source could not fall under this special provision

and, in addition, must be in a Class 1 location. The EPA 

requests comment on whether engines located in class location 

units where buildings with four or more stories above ground are 

prevalent (Class 4 areas under the DOT classification system) 

should also specifically not be considered remote.
Page 46 of 200

Stakeholders from the oil and gas industry have indicated 

to the EPA that the DOT system is well-established and there 

would be substantial overlap between engines on natural gas 

pipelines affected by the rule and covered by the DOT pipeline 

classification system. Incorporating this approach would also 

create harmonization between the EPA and DOT and would reduce 

the implementation and enforcement burden for states. 

Implementation for affected sources would also be less 

burdensome because the system is already in place and used by 

the natural gas pipeline industry and covers the majority of 

these engines. Stakeholders have indicated they are required to 

review the class location status of natural gas pipeline 

segments annually. The EPA believes this approach is reasonable 

for defining the subcategory of remote engines for those engines 

that are associated with natural gas pipelines. For those 

engines not associated with pipelines, the EPA is using similar 

criteria. An engine would be considered to be in sparsely 

populated areas if within 0.25 mile radius of the engine there 

are 5 or fewer buildings intended for human occupancy. EPA 

requests comment on whether, to be considered remote, an engine 

not associated with a natural gas pipeline should also need to 

be farther than 100 yards (91 meters) of either a building or a 

small, well-defined outside area (such as a playground, 

recreation area, outdoor theater, or other place of public 
Page 47 of 200

assembly) that is occupied by 20 or more persons on at least 5 

days a week for 10 weeks in any 12-month period.

The EPA is proposing management practices as generally 

available control technologies for existing stationary SI 4SLB 

and 4SRB area source non-emergency engines located in sparsely 

populated areas. Given the remote location of the engines from 

human activity, the EPA believes that it is appropriate not to 

include requirements that would necessitate aftertreatment and 

extensive testing and monitoring. The EPA has previously 

estimated that the costs of oxidation catalyst for existing 4SLB 

and 4SRB engines above 500 HP at area sources are $310 and $150 

million, for capital and annual costs, respectively. The capital 

and annual costs of the RICE NESHAP for existing 4SLB and 4SRB 

engines above 500 HP at area sources would be $30 million and 

$12 million, respectively, if these proposed amendments are 

incorporated into the rule. Creating a subcategory of these 

engines for the ones located in sparsely populated areas and not 

mandating emission controls would significantly reduce the cost 

of the rule for such engines.

For existing stationary SI 4SLB and 4SRB area source nonemergency engines that are located in populated areas, the EPA 

is proposing an equipment standard that requires the 

installation and operation of a catalyst that will have to be 

tested initially and annually to ensure that the catalyst is 
Page 48 of 200

working properly and reducing emissions as required. In 

addition, these units will be required to have devices to shut 

down the engine if the catalyst is exposed to dangerous 

temperatures or have continuous monitoring equipment installed 

to record catalyst inlet temperatures. The EPA is proposing 

shorter test duration and less rigorous methods than currently 

required while still ensuring that HAP reductions remain at 

expected levels for these engines located in populated areas.

The specific amendments the EPA is proposing are discussed 

below.

2. Proposed Amendments

Owners and operators of engines in sparsely populated 

areas would have to conduct a review of the surrounding area

every 12 months to determine if the nearby population has 

changed. If the engine no longer meets the criteria for a 

sparsely populated area the owner and operator must within 1 

year comply with the emission standards specified below for 

populated areas. The EPA requests comment on whether engines 

that are not associated with pipelines should be required to 

conduct the review less frequently than every 12 months.

Owners and operators of existing stationary 4SLB and 4SRB 

greater than 500 HP at area sources that are in sparsely 

populated areas as described above would be required to perform 

the following:
Page 49 of 200

 Change oil and filter every 1,440 hours of operation or 

annually, whichever comes first;

 Inspect spark plugs every 1,440 hours of operation or 

annually, whichever comes first, and replace as necessary; 

and

 Inspect all hoses and belts every 1,440 hours of operation 

or annually, whichever comes first, and replace as 

necessary.

Sources have the option to use an oil analysis program as 

described in §63.6625(i) of the rule in order to extend the 

specified oil change requirement. The oil analysis must be 

performed at the same frequency specified for changing the oil 

in Table 2d of the rule. The analysis program must at a minimum 

analyze the following three parameters: Total Acid Number, 

viscosity, and percent water content. The condemning limits for 

these parameters are as follows: Total Acid Number increases by 

more than 3.0 milligrams of potassium hydroxide per gram from 

Total Acid Number of the oil when new; viscosity of the oil has 

changed by more than 20 percent from the viscosity of the oil 

when new; or percent water content (by volume) is greater than 

0.5. If all of these condemning limits are not exceeded, the 

engine owner or operator is not required to change the oil. If 

any of the limits are exceeded, the engine owner or operator 

must change the oil within 2 days of receiving the results of 
Page 50 of 200

the analysis; if the engine is not in operation when the results 

of the analysis are received, the engine owner or operator must 

change the oil within 2 days or before commencing operation, 

whichever is later. The owner or operator must keep records of 

the parameters that are analyzed as part of the program, the 

results of the analysis, and the oil changes for the engine. The 

analysis program must be part of the maintenance plan for the 

engine.

Owners and operators of existing stationary 4SLB and 4SRB 

area source engines above 500 HP in sparsely populated areas 

would also have to operate and maintain the stationary RICE and 

aftertreatment control device (if any) according to the 

manufacturer's emission-related written instructions or develop 

their own maintenance plan which must provide to the extent 

practicable for the maintenance and operation of the engine in a 

manner consistent with good air pollution control practice for 

minimizing emissions. 

For engines in populated areas, i.e., existing stationary 

4SLB and 4SRB non-emergency engines greater than 500 HP at area 

sources that are located on DOT Class 2 through Class 4 pipeline 

segments or, for engines not associated with pipelines, that do 

not meet the 0.25 mile radius with 5 or less buildings criteria,

the EPA is proposing to adopt an equipment standard requiring 

the installation of a catalyst to reduce HAP emissions. Owners 
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and operators of existing area source 4SLB non-emergency engines 

greater than 500 HP in populated areas would be required to

install an oxidation catalyst. Owners and operators of existing 

area source 4SRB non-emergency engines greater than 500 HP in 

populated areas would be required to install NSCR. Owners and 

operators must conduct an initial test to demonstrate that the 

engine achieves at least a 93 percent reduction in CO emissions 

or a CO concentration level of 47 ppmvd at 15 percent O2, if the 

engine is a 4SLB engine. Similarly, owners and operators must 

conduct an initial performance test to demonstrate that the 

engine achieves at least a 75 percent CO reduction or a 30 

percent THC reduction, if the engine is a 4SRB engine. The 

initial test must consist of three test runs. Each test run must 

be of at least 15 minute duration, except that each test run 

conducted using the proposed appendix A to 40 CFR part 63, 

subpart ZZZZ must consist of one measurement cycle as defined by 

the method and include at least 2 minutes of test data phase 

measurement. To measure CO, emission sources must use the CO 

methods already specified in subpart ZZZZ, or the proposed 

appendix A to 40 CFR part 63, subpart ZZZZ. The THC testing must

be conducted using EPA Method 25A.

The owner or operator of both engine types must also use a 

high temperature shutdown device that detects if the catalyst 

inlet temperature is too high, or, alternatively, the owner or 
Page 52 of 200

operator can monitor the catalyst inlet temperature continuously 

and maintain the temperature within the range specified in the 

rule. For 4SLB engines the catalyst inlet temperature must 

remain at or above 450°F and at or below 1,350°F. For 4SRB 

engines the temperature range must be greater than or equal to 

750°F and less than or equal to 1,250°F at the catalyst inlet. 

Owners and operators must in addition to the initial 

performance test conduct annual checks of the catalyst to ensure 

proper catalyst activity. The annual check of the catalyst must 

at a minimum consist of one 15-minute run using the methods 

discussed above, except that each test run conducted using the 

proposed appendix A to 40 CFR part 63, subpart ZZZZ must consist 

of one measurement cycle as defined by the method and include at 

least 2 minutes of test data phase measurement. Owners and 

operators of 4SLB engines must demonstrate during the catalyst 

activity test that the catalyst achieves at least a 93 percent 

reduction in CO emissions or that the engine exhaust CO 

emissions are no more than 47 ppmvd at 15 percent O2. Owners and 

operators of 4SRB engines must demonstrate that their catalyst 

is reducing CO emissions by 75 percent or more, or 

alternatively, that THC emissions are being reduced by at least 

30 percent during the catalyst activity check. 

If the emissions from the engine do not exceed the levels 

required for the initial test or annual checks of the catalyst, 
Page 53 of 200

then the catalyst is considered to be working properly. If the 

emissions exceed the specified pollutant levels in the rule, the 

exceedance(s) is/are not considered a violation, but the owner 

or operator would be required to shut down the engine and take 

appropriate corrective action (e.g., repairs, clean or replace 

the catalyst, as appropriate). A follow-up test must be 

conducted within 7 days of the engine being started up again to 

demonstrate that the emission levels are being met. If the 

retest shows that the emissions continue to exceed the specified 

levels, the stationary RICE must again be shut down as soon as 

safely possible, and the engine may not operate, except for 

purposes of start-up and testing, until the owner/operator 

demonstrates through testing that the emissions do not exceed 

the levels specified.

D. Stationary Agricultural RICE in San Joaquin Valley 

In the 2010 amendments to the RICE NESHAP, the EPA required 

existing non-emergency CI engines above 300 HP to meet a 

standard of either 70 percent reduction of CO emissions or 49 

ppmvd CO, for engines between 300 and 500 HP, or 23 ppmvd CO for 

engines above 500 HP. The requirements also included testing and 

monitoring provisions. As with all requirements for existing 

engines in that rule, owners and operators were required to meet 

the requirements within 3 years of the effective date of the 

regulations (May 3, 2013).
Page 54 of 200

Since the finalization of the rule for existing stationary 

CI engines, stakeholders from the agricultural industry in the 

San Joaquin Valley area of California have expressed concern 

regarding the effect of certain of these requirements on engines 

in the San Joaquin Valley. The San Joaquin Valley Air Pollution 

Control District (APCD) has indicated that there are 17 

stationary CI engines at area sources in San Joaquin Valley

certified to the Tier 3 standards in 40 CFR part 89 that were 

installed between January 1 and June 12, 2006. Under the NESHAP, 

stationary CI engines at area sources are existing if 

construction of the engine commenced prior to June 12, 2006. 

These 17 Tier 3 engines in the San Joaquin Valley, which were 

built to meet stringent emission standards, would not be able to 

comply with the applicable RICE NESHAP emission standards for 

existing engines without further testing and monitoring, and 

possible retrofit with further controls, due to differences in 

the emission standards and testing protocols in the RICE NESHAP 

versus the Tier 3 standards in 40 CFR part 89. However, an 

identical engine certified to the Tier 3 standards (or Tier 2 

standards for engines above 560 kilowatts (kW)) in 40 CFR part 

89 that was installed after June 12, 2006, would not have to be 

retrofit in order to comply with the NESHAP. Stationary CI 

engines installed after June 12, 2006, at area sources of HAP 

are required to comply with the NSPS for stationary CI engines, 
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which requires engines to be certified to the standards in 40 

CFR parts 89, 94, 1039, and 1042, as applicable. Thus, a 2006 

model year stationary CI engine installed after June 12, 2006,

that is certified to the applicable standards would meet the 

requirements of the NESHAP without further controls or testing. 

While the EPA does not know if other certified Tier 3 engines

besides these 17 engines in the San Joaquin Valley were 

installed prior to June 12, 2006, EPA believes the same 

rationale should apply to any such engine.

The EPA believes that the Tier 3 standards (Tier 2 for 

engines above 560 kW) are technologically stringent regulations 

and believes it is unnecessary to require further regulation of 

engines meeting these standards. Engines meeting the Tier 3 

standards typically employed emission control technologies such 

as combustion optimization and better fuel control to meet the 

Tier 3 standards. In order to address the concerns raised by the 

engine owners in the San Joaquin Valley, the EPA is proposing 

changes to amend the requirements for any certified Tier 3 (Tier 

2 for engines above 560 kW) stationary CI engine located at an 

area source and installed before June 12, 2006. The EPA is 

proposing amendments to specify that any existing certified Tier 

3 (Tier 2 for engines above 560 kW) CI engine that was installed 

before June 12, 2006, is in compliance with the NESHAP. This 

amendment would include any existing stationary Tier 3 (Tier 2 
Page 56 of 200

for engines above 560 kW) certified CI engine located at an area 

source of HAP emissions.

Another concern brought to the EPA’s attention by the San 

Joaquin Valley agricultural industry is that due to state and 

local requirements in the San Joaquin Valley, many of the Tier 1 

and Tier 2 stationary CI engines that are regulated as existing 

sources under the NESHAP must be replaced in the next few years, 

only a short time after the emission standards for existing 

engines must be met. Specifically, the San Joaquin Valley APCD

rule for internal combustion engines (Rule 4702) requires Tier 1 

and Tier 2 certified engines to meet Tier 4 standards by January 

1, 2015, or 12 years after the installation date, but no later 

than June 1, 2018. The concern is that owners and operators of 

these engines would have to install aftertreatment by 2013 to 

meet the emission standards of the RICE NESHAP and then only a 

few years later be required to replace their engines per San 

Joaquin Valley APCD Rule 4702. The San Joaquin Valley APCD has 

identified 49 Tier 1 engines and 360 Tier 2 engines that are 

scheduled to be replaced under the local rule. The EPA has not 

identified any engines outside the San Joaquin Valley APCD area 

that are in the same or similar situation (i.e., required to be 

replaced shortly after the compliance date for existing 

engines), but the EPA does not preclude the possibility that 
Page 57 of 200

there are such engines in other areas, and requests comment and 

information on other areas that may have similar concerns.

The EPA does not think it is appropriate to require 

emission controls on a stationary CI engine that is going to be 

retired only a short time after the rule goes into effect. 

Stationary CI engines would have to comply with this rule by May 

3, 2013, and owners of engines above 300 HP are expected to have 

to install aftertreatment on their engines in order to meet the 

emission standards. The EPA estimates that the one-time cost to 

equip a 500 HP stationary CI engine with the controls necessary 

to meet the emission standards under this rule is close to 

$14,000 and more than $3,000 on a yearly basis, not accounting 

for additional costs associated with monitoring, testing, 

recordkeeping and reporting. These engines (equipped with 

aftertreatment) could end up being in operation for less than 2 

years or at most only 5 years before having to be replaced with 

a certified Tier 4 engine, as required by San Joaquin Valley 

District Rule 4702. It would not be reasonable to require the 

engine owner to invest in costly controls and monitoring 

equipment for an engine that will be replaced shortly after the 

installation of the controls.

Consequently, the EPA is proposing amendments to existing 

stationary CI engines located at area sources of HAP emissions 

to address this concern. The EPA is proposing to amend the 
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requirements for existing stationary Tier 1 and Tier 2 certified 

CI engines located at area sources that are greater than 300 HP 

that are subject to a state or local rule that requires the 

engine to be replaced. The EPA is proposing to allow these 

engines to meet management practices from the applicable May 3, 

2013, compliance date until January 1, 2015, or 12 years after 

installation date (whichever is later), but not later than June 

1, 2018. This proposed change would provide owners enough time 

to replace their engines without mandating a possibly cost 

prohibitive requirement to change all of the engines in a short 

amount of time, while still requiring that replacement of the 

engine or a retrofit of the engine occur relatively quickly 

after the owner would have to comply with the NESHAP. The EPA is 

proposing that these engines be subject to management practices 

until January 1, 2015, or 12 years after installation date

(whichever is later), but not later than June 1, 2018, after 

which time the CO emission standards discussed above (and that 

are in Table 2d of the rule) apply. The management practices 

include requirements for when to inspect and replace the engine 

oil and filter, air cleaner, hoses and belts. The complete 

details of which management practices are required are shown in 

Table 2d of the rule. Owners and operators of these existing 

stationary CI engines located at area sources of HAP emissions

that intend to meet management practices rather than the 
Page 59 of 200

emission limits prior to January 1, 2015, or 12 years after 

installation date, but not later than June 1, 2018, must submit 

a notification by March 3, 2013, stating that they intend to use 

this provision and identifying the state or local regulation 

that the engine is subject to.

E. Remote Areas of Alaska

1. Background

The RICE NESHAP currently specifies less stringent 

requirements for existing non-emergency CI engines at area 

sources located in remote areas of Alaska. Remote areas are 

defined as those not accessible by the FAHS. The FAHS includes 

areas with year-round ferry service that are not on the 

contiguous road system. Under the current regulation, stationary 

non-emergency CI engines at area sources in areas of Alaska that 

are not accessible by the FAHS are subject to management 

practices as opposed to numerical emission standards.

Following the publication of the final rule in 2010, the 

EPA received requests to expand the definition of remote areas

of Alaska. Stakeholders asserted that facilities in areas that 

are accessible by the FAHS but are not connected to the Alaska 

Railbelt grid face the same challenges as those in areas not 

accessible by the FAHS. The Alaska Railbelt Grid refers to the 

service areas of the six regulated public utilities that extend 

from Fairbanks to Anchorage and the Kenai Peninsula. These 
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utilities are the Golden Valley Electric Association, Chugach 

Electric Association, Matanuska Electric Association, Homer 

Electric Association, Anchorage Municipal Light & Power, and the 

City of Seward Electric System. According to the stakeholders, 

one reason for broadening the definition of remote areas in 

Alaska is high energy costs, which provide a natural incentive 

to run CI engines as little as possible. The cost of energy is 

utilities’ greatest concern in Alaska. Also, the stakeholders 

indicated that extreme weather conditions in certain areas of 

Alaska is another reason for including additional areas in the 

definition of remote areas of Alaska. The climate issue is 

unique to remote areas of Alaska that experience some of the 

most extreme temperatures in the country. Heavy snowfall and 

high winds are not uncommon in several areas that are accessible 

by the FAHS. For instance, Copper Valley Electric Association 

(CVEA) is a utility accessible by the FAHS, but it includes 

areas that face the same challenges as other communities not 

accessible by the FAHS. The utility operates on an isolated grid 

and relies on diesel power generation. In one of CVEA’s 

territories, Valdez, Alaska, CVEA indicated that this area 

experiences brutal conditions and stated that Valdez is 

considered to have the greatest snowfall (326 inches per winter) 

in any city of the United States. Also, winds at more than 100 

miles per hour are not uncommon for Valdez, Alaska, according to 
Page 61 of 200

CVEA. Temperatures between 40 and 50 below zero are also not 

abnormal, which emphasizes the extreme reliance on power, CVEA 

asserted. Travel times and accessibility are issues on a regular 

basis, but can be additionally exacerbated due to severe 

weather, which in some cases may lead to avalanches and road 

closings. In particular, even if a site is on the FAHS, in the 

event of poor weather conditions and road closings, there are in 

many cases no alternate roads to travel on. Further, access to 

specific isolated sites can also be problematic in particular 

remote areas of Alaska and the problems are unique to Alaska

because of the infrastructure and environment. For example, 

communities made the case that sources along the AMHS that are 

only accessible by the AMHS should be treated the same way as 

communities not accessible by the FAHS. The AMHS primarily 

serves passengers and vehicles, and is not intended for 

transporting goods. Therefore, the same methods used to bring in 

goods to communities not on the FAHS are the same as those 

Alaskan villages served only by the AMHS. Goods are typically 

brought in to remote communities by barge and this is another 

example of a scenario that is unique to Alaska. Other arguments 

for expanding the definition of remote areas of Alaska beyond 

those not accessible by the FAHS include very low population 

density in many other remote areas although accessible by the 

FAHS, and the fact that many of these areas are not connected to 
Page 62 of 200

the electric grid and rely on back up diesel generation to 

support fluctuating renewable energy systems. The energy supply 

system is another area that is particularly different in Alaska 

compared to the rest of the country where the majority of 

customers are connected to the grid. Therefore, for the reasons 

discussed, the EPA is proposing expansion of the remote area 

source category. This proposal is supported by the Alaska 

Department of Environmental Conservation and communities with 

whom the EPA has discussed this issue.

2. Proposed Amendments

The EPA is proposing to expand the current definition of 

remote areas of Alaska to extend beyond areas that are not 

accessible by the FAHS. Specifically, the EPA is proposing that 

areas of Alaska that are accessible by the FAHS and that meet 

all of the following criteria are also considered remote and 

subject to management practices under the rule:

 The stationary CI engine is located in an area not 

connected to the Alaska Railbelt Grid,

 At least 10 percent of the power generated by the engine 

per year is used for residential purposes, and

 The system capacity is less than 12 megawatts, or the 

engine is used exclusively for backup power for renewable 

energy and is used less than 500 hours per year on a 10-

year rolling average.
Page 63 of 200

The EPA is proposing limiting the remote classification to 

engines that are used at least partially for residential 

purposes, where the impact of higher energy costs is of greatest 

concern. The classification is further limited to sources that 

are used infrequently as backup for renewable power, or that are 

at smaller capacity facilities, which are generally in more 

sparsely populated areas.

F. Miscellaneous Corrections and Revisions

The EPA is making some minor corrections to the stationary 

engine rules to address miscellaneous issues. The EPA is making 

some minor revisions in the rules to correct mistakes in the 

current rules or to clarify the rules. The revisions are as 

follows:

 Revising Tables 1b and 2b of 40 CFR part 63, subpart ZZZZ

to correct language requiring the pressure drop to be at 

plus or minus 10 percent 100 percent load for all engines. 

The engines that were regulated in 2010 are not subject to 

the load requirements and therefore the EPA is correcting 

these tables to make this clear.

 Adding a footnote to Table 1b of 40 CFR part 63, subpart 

ZZZZ stating that sources can petition the Administrator 

for a different temperature range consistent with Table 2b 

of the rule.
Page 64 of 200

 Correcting rows 8 and 10 in Table 2d of 40 CFR part 63, 

subpart ZZZZ to indicate that the requirements apply to 

non-emergency, non-black start stationary RICE greater than 

500 HP that are 4SLB and 4SRB that operate more than 24 

hours per year, as intended in the original rule.

 Revising the language in §63.6625(b) of 40 CFR part 63, 

subpart ZZZZ that states “...in paragraphs (b)(1) through 

(5) of this section” to “in paragraphs (b)(1) through (6) 

of this section.”

 Changing Tables 2c and 2d of 40 CFR part 63, subpart ZZZZ,

where it currently specifies to inspect air cleaner, to 

also specify that it must be replaced as necessary.

 Revising §63.6620(b) of 40 CFR part 63, subpart ZZZZ to 

indicate that testing must be conducted within plus or 

minus 10 percent of 100 percent load for stationary RICE 

greater than 500 HP located at a major source (except 

existing non-emergency CI stationary RICE greater than 500 

HP located at a major source) that are subject to testing.

 Specifying that, as was intended in the rule adding these 

requirements, the operating limitations (pressure drop and 

catalyst inlet temperature) in Tables 1b and 2b of 40 CFR 

part 63, subpart ZZZZ do not have to be met during startup.
Page 65 of 200

 For consistency, and as provided in the original RICE 

NESHAP for other stationary RICE, clarifying in 40 CFR part 

63, subpart ZZZZ that the existing stationary RICE 

regulated in 2010 (i.e., engines constructed before June 

12, 2006 that are less than or equal to 500 HP located at 

major sources or engines located at area sources) must burn 

landfill or digester gas equivalent to 10 percent or more 

of the gross heat input on an annual basis in order to 

qualify as a landfill or digester gas engine under the 

rule.

 Clarifying §60.4207(b) of 40 CFR part 60, subpart IIII to 

specify that owners and operators of stationary CI engines 

less than 30 liters per cylinder that are subject to the 

subpart that use diesel fuel must use diesel fuel that 

meets the requirements of 40 CFR 80.510(b), except owners 

and operators may use up any diesel fuel acquired prior to 

October 1, 2010, that does not meet the requirements of 40 

CFR 80.510(b) for nonroad diesel fuel.

 Adding appendix A to 40 CFR part 63, subpart ZZZZ, which 

includes procedures that can be used for measuring CO 

emissions from existing stationary 4SLB and 4SRB stationary 

RICE above 500 HP located at area sources of HAP that are 

complying with the emission limits in Table 2d of 40 CFR 

part 63, subpart ZZZZ. 
Page 66 of 200

 Reinstating the footnotes for Table 2 of 40 CFR part 60, 

subpart JJJJ. The footnotes were inadvertently removed when 

the rule was amended on June 28, 2011 (76 FR 37954).

 Adding “part 60” in Table 4 of the NESHAP, in row 2 where 

it refers to 40 CFR appendix A.

 Clarifying in §63.6625(a) of 40 CFR part 63, subpart ZZZZ

that a continuous emission monitoring system is only 

required to be installed at the outlet of the control 

device for engines that are complying with the requirement 

to limit the concentration of CO.

 Clarifying that, as was intended in the rule adding these 

requirements, all of the standards for stationary SI RICE 

in §60.4231(b) of 40 CFR part 60, subpart JJJJ are for 

stationary SI RICE that use gasoline.

 Clarifying that, as was intended in the rule adding these 

requirements, all of the standards for stationary SI RICE 

in §60.4231(c) of 40 CFR part 60, subpart JJJJ are for 

stationary SI RICE that are rich burn engines that use LPG.

 Clarifying that, as was intended in the rule adding these 

requirements, all of the standards for stationary SI RICE 

in §60.4231(d) of 40 CFR part 60, subpart JJJJ are for 

stationary SI RICE that are not gasoline engines or rich 

burn engines that use LPG.
Page 67 of 200

G. Compliance Date

The EPA has received questions regarding whether the 

compliance dates for engines impacted by the 2010 amendments and 

this proposed reconsideration will be extended. Affected sources 

that may be impacted by this action have expressed concern about 

having sufficient time to comply with the rule by the compliance 

date, which is May 3, 2013, for existing stationary CI RICE and 

October 19, 2013, for existing stationary SI RICE. Sources 

impacted by this reconsideration are particularly concerned with 

compliance in the event that the EPA does not finalize changes 

that are substantially similar to the changes being proposed in 

this action. The EPA does not intend to extend the May 3, 2013,

and October 19, 2013, compliance dates, because there are many 

engines that must meet those compliance dates that are not 

impacted by this reconsideration. However, the EPA notes that 

sources that are affected by the reconsideration and that may 

need additional time to install controls to comply with the 

applicable requirements can request up to an additional year to 

install controls, as specified in 40 CFR 63.6(i). The EPA 

requests comment regarding whether special consideration should 

be given to engines whose requirements would be reduced by this 

proposal if, in the final rule, the EPA does not finalize the 

proposed reduced requirements.

III. Summary of Environmental, Energy and Economic Impacts
Page 68 of 200

A. What are the air quality impacts?

The EPA estimates that the rule with the proposed 

amendments incorporated will reduce emissions from existing 

stationary RICE as shown in Table 1 of this preamble. The

emissions reductions the EPA previously estimated for the 2010 

amendments to the RICE NESHAP are shown for comparison. 

Reductions are shown for the year 2013, which is the first year 

the final RICE NESHAP will be implemented for existing 

stationary RICE.

Table 1. Summary of Reductions for Existing Stationary RICE

Pollutant

Emission Reductions (tpy) 

in the year 2013

2010 Final Rule

2010 Final Rule with 

these Proposed 

Amendments

CI SI CI SI

HAP 1,014 6,008 1,005 1,778

CO 14,342 109,321 14,238 22,211

PM 2,844 N/A 2,818 N/A

NOx N/A 96,479 N/A 9,648

VOC 27,395 30,907 27,142 9,147

The EPA estimates that more than 900,000 stationary CI 

engines will be subject to the rule in total, but only a small 

number of stationary CI engines are affected by the proposed 

amendments in this action. It is estimated that approximately 

330,000 stationary SI engines will be subject to the rule in 

total; however, only a subset of stationary SI engines are 

affected by the proposed amendments in this action. The decrease 
Page 69 of 200

in estimated reductions for SI engines is primarily due to 

proposed amendments to the requirements for existing 4SRB and 

4SLB SI engines larger than 500 HP at area sources of HAP that 

are in remote areas. Those engines were required by the 2010 

rule to meet emission limits that were expected to require the 

installation of aftertreatment to reduce emissions; under these 

proposed amendments, those engines are required to meet 

management practices that would not require the installation of 

aftertreatment. Further information regarding the estimated 

reductions of this final rule can be found in the memorandum 

titled, “RICE NESHAP Reconsideration Amendments - Cost and 

Environmental Impacts,” which is available in the docket (EPAHQ-OAR-2008-0708). The EPA did not estimate any reductions 

associated with the minor changes to the NSPS for stationary CI 

and SI engines.

B. What are the cost impacts?

The proposed amendments are expected to reduce the overall 

cost of the original 2010 RICE NESHAP amendments. The EPA 

estimates that with these proposed amendments incorporated the 

cost of the rule for existing stationary RICE will be as shown 

in Table 2 of this preamble. The costs the EPA previously 

estimated for the 2010 amendments to the RICE NESHAP are shown 

for comparison. The costs that were previously estimated are 
Page 70 of 200

shown in the original year ($2008 for CI and $2009 for SI), as 

well as updated to 2010 dollars. 

Table 2. Summary of Cost Impacts for Existing Stationary RICE

Engine 2010 Final Rule 2010 Final Rule with 

these Proposed Amendments

Total Annual Cost

SI $253 million 

($2009)

$251 million 

($2010)

$115 million ($2010)

CI $373 million 

($2008)

$375 million 

($2010)

$373 million ($2010)

Total Capital Cost

SI $383 million 

($2009)

$380 million 

($2010)

$103 million ($2010)

CI $744 million 

($2008)

$748 million 

($2010)

$740 million ($2010)

Further information regarding the estimated cost impacts of the

proposed amendments, including the cost of the proposed 

amendments in 2010 dollars, can be found in the memorandum 

titled, “RICE NESHAP Reconsideration Amendments - Cost and 

Environmental Impacts,” which is available in the docket (EPAHQ-OAR-2008-0708). The EPA did not estimate costs associated 

with the changes to the NSPS for stationary CI and SI engines. 

The changes to the NSPS are minor and are not expected to impact 

the costs of those rules.

C. What are the benefits?

Emission controls installed to meet the requirements of 

these rules will generate benefits by reducing emissions of HAP 

as well as criteria pollutants and their precursors, including 

CO, NOx and VOC. NOx and VOC are precursors to PM2.5 (particles
Page 71 of 200

smaller than 2.5 microns) and ozone. The criteria pollutant 

benefits are considered co-benefits for these rules. For these 

rules, we were only able to quantify the health co-benefits 

associated with reduced exposure to PM2.5 from emission reductions 

of NOx and directly emitted PM2.5. 

The EPA previously estimated that the monetized co-benefits 

in 2013 of the stationary CI NESHAP would be $940 million to 

$2,300 million (2008 dollars) at a 3-percent discount rate and 

$850 million to $2,100 million (2008 dollars) at a 7-percent 

discount rate.

5 For stationary SI engines, EPA previously 

estimated that the monetized co-benefits in 2013 would be $510

million to $1,200 million (2009 dollars) at a 3-percent discount 

rate) and $460 million to $1,100 million (2009 dollars) at a 7-

percent discount rate.

6

The proposed amendments are expected to reduce the overall 

emission reductions of the rules. In addition to revising the 

anticipated emission reductions, we have also updated the 

methodology used to calculate the co-benefits to be consistent 

 

5 U.S. Environmental Protection Agency. 2010. Regulatory Impact 

Analysis (RIA) for Existing Stationary Compression Ignition 

Engines NESHAP: Final Draft. Research Triangle Park, NC. 

February.

http://www.epa.gov/ttn/ecas/regdata/RIAs/CIRICENESHAPRIA2-17-

0cleanpublication.pdf.

6 U.S. Environmental Protection Agency. 2010. Regulatory Impact 

Analysis (RIA) for Existing Stationary Spark Ignition (SI) RICE 

NESHAP: Final Report. Research Triangle Park, NC. August. 

http://www.epa.gov/ttn/ecas/regdata/RIAs/riceriafinal.pdf.
Page 72 of 200

with methods used in more recent rulemakings, which is 

summarized below and discussed in more detail in the Regulatory 

Impact Analysis (RIA). We estimate the monetized co-benefits of 

the proposed amendments of the CI NESHAP in 2013 to be $770 

million to $1,900 million (2010 dollars) at a 3-percent discount 

rate and $690 million to $1,700 million (2010 dollars) at a 7-

percent discount rate. For SI engines, we estimate the monetized 

co-benefits of the proposed amendments in 2013 to be $62 million 

to $150 million (2010 dollars) at a 3-percent discount rate and 

$55 million to $140 million (2010 dollars) at a 7-percent 

discount rate.

Using alternate relationships between PM2.5 and premature 

mortality supplied by experts, higher and lower co-benefits 

estimates are plausible, but most of the expert-based estimates 

fall between these two estimates.7 A summary of the monetized cobenefits estimates for CI and SI engines at discount rates of 3 

percent and 7 percent is in Table 3 of this preamble.

 

7 Roman, et al., 2008. Expert Judgment Assessment of the 

Mortality Impact of Changes in Ambient Fine Particulate Matter 

in the U.S., Environ. Sci. Technol., 42, 7, 2268 – 2274.
Page 73 of 200

Table 3. Summary of the Monetized PM2.5 Co-Benefits for Proposed 

Amendments to the NESHAP for Stationary CI and SI Engines 

(millions of 2010 dollars)a, b

Pollutant

Emission 

reductions 

(tons per 

year)

Total monetized 

co-benefits

(3 percent 

Discount)

Total monetized 

co-benefits

(7 percent 

Discount)

Original 2010 Final Rulesc

Stationary CI Engines

Total 

Benefits

2,844 PM2.5

27,395 VOC $950 to $2,300 $860 to $2,100

Stationary SI Engines

Total 

Benefits

96,479 NOx

30,907 VOC $510 to $1,300 $470 to $1,100

2010 Final Rules with these Proposed Amendments

Stationary CI Engines

Directly 

emitted PM2.5

2,818 $770 to $1,900 $690 to $1,700

Stationary SI Engines

NOx 9,648 $62 to $150 $55 to $140

a All estimates are for the analysis year (2013) and are rounded 

to two significant figures so numbers may not sum across rows. 

The total monetized co-benefits reflect the human health 

benefits associated with reducing exposure to PM2.5 through 

reductions of PM2.5 precursors, such as NOX and directly emitted 

PM2.5. It is important to note that the monetized co-benefits do 

not include reduced health effects from exposure to HAP, direct 

exposure to NO2, exposure to ozone, ecosystem effects or 

visibility impairment. 

b PM co-benefits are shown as a range from Pope, et al. (2002) to 

Laden, et al. (2006). These models assume that all fine 

particles, regardless of their chemical composition, are equally 

potent in causing premature mortality because the scientific 

evidence is not yet sufficient to allow differentiation of 

effects estimates by particle type.

c The benefits analysis for the 2010 final rules applied outdated benefit-per-ton estimates compared to the updated 

estimates described in this preamble and reflected monetized cobenefits for VOC emissions, which limits direct comparability 

with the monetized co-benefits estimated for these proposed 

rules. In addition, these estimates have been updated from their 

original currency years to 2010$, so the rounded estimates for 

the 2010 final rules may not match the original RIAs.
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These co-benefits estimates represent the total monetized 

human health benefits for populations exposed to less PM2.5 in 

2013 from controls installed to reduce air pollutants in order 

to meet these rules. To estimate human health co-benefits of 

these rules, the EPA used benefit-per-ton factors to quantify 

the changes in PM2.5-related health impacts and monetized 

benefits based on changes in directly emitted PM2.5 and NOx 

emissions. These benefit-per-ton factors were derived using the 

general approach and methodology laid out in Fann, Fulcher, and 

Hubbell (2009).

8 This approach uses a model to convert emissions 

of PM2.5 precursors into changes in ambient PM2.5 levels and 

another model to estimate the changes in human health associated 

with that change in air quality, which are then divided by the 

emission reductions to create the benefit-per-ton estimates. 

However, for these rules, we utilized air quality modeling of 

emissions in the “Non-EGU Point other” category because we do 

not have modeling specifically for stationary engines.9,10 The 

 

8 Fann, N., C.M. Fulcher, B.J. Hubbell. 2009. The influence of 

location, source, and emission type in estimates of the human 

health benefits of reducing a ton of air pollution. Air Qual 

Atmos Health (2009) 2:169–176.

9 U.S. Environmental Protection Agency. 2012. Technical support 

document: Estimating the benefit per ton of reducing PM2.5

precursors from other point sources. Research Triangle Park, NC.

10 Stationary engines are included in the other non-EGU point 

source category. If the affected stationary engines are more 

rural than the average of the non-EGU sources modeled, then it 

is possible that the benefits may be somewhat less than we have 
Page 75 of 200

primary difference between the estimates used in this analysis 

and the estimates reported in Fann, Fulcher, and Hubbell (2009) 

is the air quality modeling data utilized. While the air quality 

data used in Fann, Fulcher, and Hubbell (2009) reflects broad 

pollutant/source category combinations, such as all non-EGU 

stationary point sources, the air quality modeling data used in 

this analysis has narrower sector categories. In addition, the 

updated air quality modeling data reflects more recent emissions 

data (2005 rather than 2001) and has a higher spatial resolution 

(12km rather than 36 km grid cells). The benefits methodology, 

such as health endpoints assessed, risk estimates applied, and 

valuation techniques applied did not change. As a result, the 

benefit-per-ton estimates presented herein better reflect the 

geographic areas and populations likely to be affected by this 

sector. However, these updated estimates still have similar 

limitations as all national-average benefit-per-ton estimates in 

that they reflect the geographic distribution of the modeled 

emissions, which may not exactly match the emission reductions 

in this rulemaking, and they may not reflect local variability 

in population density, meteorology, exposure, baseline health 

 

estimated here. The TSD provides the geographic distribution of 

the air quality changes associated with this sector. It is 

important to emphasize that this modeling represents the best 

available information on the air quality impact on a per ton 

basis for these sources.
Page 76 of 200

incidence rates, or other local factors for any specific 

location.

We apply these national benefit-per-ton estimates

calculated for this sector separately for directly emitted PM2.5

and NOx and multiply them by the corresponding emission 

reductions. The sector modeling does not provide estimates of 

the PM2.5-related benefits associated with reducing VOC 

emissions, but these unquantified benefits are generally small 

compared to other PM2.5 precursors. More information regarding the 

derivation of the benefit-per-ton estimates for this category is 

available in the technical support document, which is available 

in the docket.

These models assume that all fine particles, regardless of 

their chemical composition, are equally potent in causing 

premature mortality because the scientific evidence is not yet 

sufficient to allow differentiation of effects estimates by 

particle type. The main PM2.5 precursors affected by these rules

are directly emitted PM2.5 and NOX. Even though we assume that all 

fine particles have equivalent health effects, the benefit-perton estimates vary between precursors depending on the location 

and magnitude of their impact on PM2.5 levels, which drive 

population exposure. For example, directly emitted PM2.5 has a 

lower benefit-per-ton estimate than direct PM2.5 because it does 
Page 77 of 200

not form as much PM2.5; thus, the exposure would be lower, and 

the monetized health benefits would be lower.

It is important to note that the magnitude of the PM2.5 cobenefits is largely driven by the concentration response 

function for premature mortality. Experts have advised the EPA 

to consider a variety of assumptions, including estimates based 

both on empirical (epidemiological) studies and judgments 

elicited from scientific experts, to characterize the 

uncertainty in the relationship between PM2.5 concentrations and 

premature mortality. We cite two key empirical studies, one 

based on the American Cancer Society cohort study11 and the 

extended Six Cities cohort study.12 In the RIA for this proposed 

amendments rule, which is available in the docket, we also 

include benefits estimates derived from the expert judgments and 

other assumptions.

The EPA strives to use the best available science to 

support our benefits analyses. We recognize that interpretation 

of the science regarding air pollution and health is dynamic and 

evolving. After reviewing the scientific literature, we have 

determined that the no-threshold model is the most appropriate 

 

11 Pope, et al., 2002. Lung Cancer, Cardiopulmonary Mortality, 

and Long-term Exposure to Fine Particulate Air Pollution. 

Journal of the American Medical Association 287:1132-1141.

12 Laden, et al., 2006. Reduction in Fine Particulate Air 

Pollution and Mortality. American Journal of Respiratory and 

Critical Care Medicine 173: 667-672.
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model for assessing the mortality benefits associated with 

reducing PM2.5 exposure. Consistent with this finding, we have 

conformed the previous threshold sensitivity analysis to the 

current state of the PM science by incorporating a new “Lowest 

Measured Level” (LML) assessment in the RIA accompanying these 

rules. While an LML assessment provides some insight into the 

level of uncertainty in the estimated PM mortality benefits, the 

EPA does not view the LML as a threshold and continues to 

quantify PM-related mortality impacts using a full range of 

modeled air quality concentrations.

Most of the estimated PM-related co-benefits for these 

rules would accrue to populations exposed to higher levels of 

PM2.5. For this analysis, policy-specific air quality data are

not available due to time or resource limitations, and thus, we 

are unable to estimate the percentage of premature mortality 

associated with this specific rule’s emission reductions at each 

PM2.5 level. As a surrogate measure of mortality impacts, we 

provide the percentage of the population exposed at each PM2.5 

level using the source apportionment modeling used to calculate 

the benefit-per-ton estimates for this sector. Using the Pope,

et al. (2002) study, 77 percent of the population is exposed to 

annual mean PM2.5 levels at or above the LML of 7.5 micrograms 

per cubic meter (μg/m3). Using the Laden, et al. (2006) study, 25 

percent of the population is exposed above the LML of 10 μg/m3.
Page 79 of 200

It is important to emphasize that we have high confidence in 

PM2.5-related effects down to the lowest LML of the major cohort 

studies. This fact is important, because, as we model avoided 

premature deaths among populations exposed to levels of PM2.5, we 

have lower confidence in levels below the LML for each study. 

Every benefit analysis examining the potential effects of a 

change in environmental protection requirements is limited, to 

some extent, by data gaps, model capabilities (such as 

geographic coverage) and uncertainties in the underlying 

scientific and economic studies used to configure the benefit 

and cost models. Despite these uncertainties, we believe the 

benefit analysis for these rules provides a reasonable 

indication of the expected health benefits of the rulemaking 

under a set of reasonable assumptions. This analysis does not 

include the type of detailed uncertainty assessment found in the 

2006 PM2.5 National Ambient Air Quality Standard (NAAQS) RIA 

because we lack the necessary air quality input and monitoring 

data to run the benefits model. In addition, we have not 

conducted air quality modeling for these rules, and using a 

benefit-per-ton approach adds another important source of 

uncertainty to the benefits estimates. The 2006 PM2.5 NAAQS 

benefits analysis13 provides an indication of the sensitivity of 

 

13 U.S. Environmental Protection Agency, 2006. Proposed 

amendments Regulatory Impact Analysis: PM2.5 NAAQS. Prepared by 
Page 80 of 200

our results to various assumptions.

It should be noted that the monetized co-benefits estimates 

provided above do not include benefits from several important 

benefit categories, including exposure to HAP, NOx, ozone 

exposure, as well as ecosystem effects and visibility 

impairment. Although we do not have sufficient information or 

modeling available to provide monetized estimates for these 

proposed amendments, we include a qualitative assessment of 

these unquantified benefits in the RIA for these proposed 

amendments.

For more information on the benefits analysis, please refer 

to the RIA for these proposed amendments, which is available in 

the docket.

D. What are the non-air health, environmental and energy 

impacts?

The EPA does not anticipate any significant non-air health, 

environmental or energy impacts as a result of these proposed 

amendments.

IV. Solicitation of Public Comments and Participation

The EPA seeks full public participation in arriving at its 

final decisions, and strongly encourages comments on all aspects 

of this proposed rule from all interested parties. Whenever 

 

Office of Air and Radiation. October. Available on the Internet 

at http://www.epa.gov/ttn/ecas/ria.html.
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applicable, full supporting data and detailed analysis should be 

submitted to allow the EPA to make maximum use of the comments. 

The agency invites all parties to coordinate their data 

collection activities with the EPA to facilitate mutually 

beneficial and cost-effective data submissions. A 

redline/strikeout version of the complete NESHAP for stationary 

RICE, which shows the changes that are being proposed in this 

action, is available from the rulemaking docket.

The EPA is seeking specific comment on the proposal to 

temporarily allow stationary emergency engines located at area 

sources to apply the 50 hours per year that is currently allowed 

under §63.6640(f) for non-emergency operation towards any type 

of non-emergency operation, including peak shaving and nonemergency demand response if the peak shaving is done as part of 

a peak shaving (load management) program with the local 

distribution system operator. The EPA is proposing that the 

allowance be removed after April 16, 2017. 

The EPA recognizes that the electricity grid achieves 

demand response and grid stability with and without the use of 

emergency stationary RICE. Alternative approaches include 

reductions or shifts in energy use, electricity storage, 

distribution automation, microgrids, natural gas-fired 

combustion turbines, and grid-connected distributed generation, 

including non-emergency engines and combined heat and power. 
Page 82 of 200

Many of these approaches can provide additional benefits, such 

as additional energy efficiency, lower costs, shorter 

electricity outage times, and better integration of renewable 

energy generation into the electricity grid. Several studies 

project a significant future potential for using less energy in 

homes, buildings, and industry during times of peak electricity 

demand. The EPA seeks comment on how these investments may 

affect the number of hours which emergency stationary RICE are 

needed in the future to address electricity peak shaving and 

grid stability.

The EPA is also specifically seeking comment on the 

proposed criteria for expanding the current definition of remote 

areas of Alaska beyond areas that are not accessible by the 

FAHS. The EPA requests comment on whether the proposed system 

capacity limitation of 12 megawatts and the alternative 500 hour 

cap on annual usage (based on a 10-year rolling average) are the 

appropriate criteria for distinguishing the areas of Alaska 

that, while accessible by the FAHS, have the same unique 

challenges as the areas that are not accessible by the FAHS. 

The EPA is also seeking information related to irrigation 

pump engine sizes. During the 2010 rulemaking, the EPA relied 

upon several sources to determine the potential number of 

irrigation engines that may be impacted by the rule. Using these 

sources, the EPA estimated that the vast majority of the 
Page 83 of 200

existing irrigation engines were less than or equal to 300 HP. 

The EPA received several comments confirming this estimation. 

The EPA seeks comprehensive, nationwide information on the size 

of existing irrigation engines to either confirm or refute our 

understanding of existing irrigation engine sizes; this 

information will assist EPA in assessing the impacts of the 2010 

rule on existing irrigation engines. The EPA has placed 

information in the docket for this rulemaking (see EPA-HQ-OAR2008-0708-0495) on the number of irrigation engines provided by 

the U.S. Department of Agriculture after the 2010 RICE NESHAP 

amendments were finalized.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and 

Executive Order 13563: Improving Regulation and Regulatory 

Review

Under section 3(f)(1) of Executive Order 12866 (58 FR 

51735, October 4, 1993), this action is an “economically 

significant regulatory action” because it is likely to have an 

annual effect on the economy of $100 million or more. 

Accordingly, the EPA submitted this action to the Office of 

Management and Budget (OMB) for review under Executive Order 

12866 and Executive Order 13563 (76 FR 3821, January 21, 2011), 

and any changes made in response to OMB recommendations have 

been documented in the docket for this action. In addition, the 
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EPA prepared a RIA of the potential costs and benefits 

associated with this action.

A summary of the monetized benefits, compliance costs and 

net benefits for the 2010 rule with the proposed amendments to 

the stationary CI engines NESHAP at discount rates of 3 percent 

and 7 percent is in Table 4 of this preamble. The summary for 

stationary SI engines is included in Table 5 of this preamble.

OMB Circular A-4 recommends that analysis of a change in an 

existing regulatory program use a baseline that assumes “no 

change” in the existing regulation. For purposes of this rule, 

however, the EPA has decided that it is appropriate to assume a 

baseline in which the original 2010 rule did not exist. The EPA 

feels that this baseline is appropriate because full 

implementation of the final rule has not taken place as of yet 

(it will take place in 2013). In addition, this assumption is 

consistent with the baseline definition applied in the recently 

proposed NESHAP for Industrial, Commercial, and Institutional 

Boilers (76 FR 80532) and NSPS for Commercial/Industrial Solid 

Waste Incineration Units (76 FR 80452).

Table 4. Summary of the Monetized Benefits, Compliance Costs and 

Net benefits for the 2010 Rule with the Proposed Amendments to 

the Stationary CI Engine NESHAP in 2013 (millions of 2010 

dollars)

a

3-Percent Discount 

Rate

7-Percent Discount 

Rate

Total Monetized 

Benefitsb $770 to $1,900 $690 to $1,700
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Total Compliance 

Costsc $373 $373

Net Benefits $400 to $1,500 $320 to $1,300

Non-Monetized 

Benefits

Health effects from exposure to HAP

Health effects from direct exposure to NO2

and ozone

Health effects from PM2.5 exposure from VOC

Ecosystem effects 

Visibility impairment 

a All estimates are for the implementation year (2013) and are 

rounded to two significant figures.

b The total monetized co-benefits reflect the human health 

benefits associated with reducing exposure to PM2.5 through 

reductions of PM2.5 precursors, such as NOX and directly emitted 

PM2.5. Co-benefits are shown as a range from Pope, et al. (2002) 

to Laden, et al. (2006). These models assume that all fine 

particles, regardless of their chemical composition, are equally 

potent in causing premature mortality because the scientific 

evidence is not yet sufficient to allow differentiation of 

effects estimates by particle type.

c The engineering compliance costs are annualized using a 7-

percent discount rate.

Table 5. Summary of the Monetized Benefits, Compliance Costs and

Net benefits for the 2010 Rule with the Proposed Amendments to 

the Stationary SI Engine NESHAP in 2013 (millions of 2010 

dollars)

a

3-Percent Discount 

Rate

7-Percent Discount 

Rate

Total Monetized 

Benefitsb $62 to $150 $55 to $140

Total Compliance 

Costsc $115 $115

Net Benefits $-53 to $35 $-60 to $25

Non-Monetized 

Benefits

Health effects from exposure to HAP

Health effects from direct exposure to NO2

and ozone

Health effects from PM2.5 exposure from VOC

Ecosystem effects 

Visibility impairment 

a All estimates are for the implementation year (2013) and are 

rounded to two significant figures.
Page 86 of 200

b The total monetized co-benefits reflect the human health 

benefits associated with reducing exposure to PM2.5 through 

reductions of PM2.5 precursors, such as NOX and directly emitted 

PM2.5. Co-benefits are shown as a range from Pope, et al. (2002) 

to Laden, et al. (2006). These models assume that all fine 

particles, regardless of their chemical composition, are equally 

potent in causing premature mortality because the scientific 

evidence is not yet sufficient to allow differentiation of 

effects estimates by particle type.

c The engineering compliance costs are annualized using a 7-

percent discount rate.

For more information on the cost-benefit analysis, please 

refer to the RIA for these proposed amendments, which is 

available in the docket.

B. Paperwork Reduction Act

This action does not impose any new information collection 

burden. This action does not impose an information collection

burden because the agency is not requiring any additional 

recordkeeping, reporting, notification or other requirements in 

these proposed amendments. The changes being proposed in this 

action do not affect information collection, but include 

revisions to emission standards and other minor issues. However, 

the OMB has previously approved the information collection 

requirements contained in the existing regulations under the 

provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et 

seq. and has assigned OMB control number 2060-0548. The OMB 

control numbers for the EPA's regulations in 40 CFR are listed 

in 40 CFR part 9.

C. Regulatory Flexibility Act
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The Regulatory Flexibility Act generally requires an agency 

to prepare a regulatory flexibility analysis of any rule subject 

to notice and comment rulemaking requirements under the 

Administrative Procedure Act or any other statute unless the 

agency certifies that the rule will not have a significant 

economic impact on a substantial number of small entities. Small 

entities include small businesses, small organizations and small 

governmental jurisdictions.

For purposes of assessing the impacts of this rule on small 

entities, small entity is defined as: (1) A small business as 

defined by the Small Business Administration’s (SBA) regulations 

at 13 CFR 121.201; (2) a small governmental jurisdiction that is 

a government of a city, county, town, school district or special 

district with a population of less than 50,000; and (3) a small 

organization that is any not-for-profit enterprise which is 

independently owned and operated and is not dominant in its 

field. The companies owning facilities with affected RICE can be 

grouped into small and large categories using SBA general size 

standard definitions. Size standards are based on industry 

classification codes (i.e., North American Industrial 

Classification System, or NAICS) that each company uses to 

identify the industry or industries in which they operate. The 

SBA defines a small business in terms of the maximum employment,

annual sales, or annual energy-generating capacity (for 
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electricity generating units—EGUs) of the owning entity. These 

thresholds vary by industry and are evaluated based on the 

primary industry classification of the affected companies. In 

cases where companies are classified by multiple NAICS codes, 

the most conservative SBA definition (i.e., the NAICS code with 

the highest employee or revenue size standard) was used. 

As mentioned earlier in this preamble, facilities across 

several industries use affected CI and SI stationary RICE; 

therefore, a number of size standards are utilized in this 

analysis. For the 15 industries identified at the 6-digit NAICS 

code represented in this analysis, the employment size standard 

(where it applies) varies from 500 to 1,000 employees. The 

annual sales standard (where it applies) is as low as 0.75 

million dollars and as high as 33.5 million dollars. In 

addition, for the electric power generation industry, the small 

business size standard is an ultimate parent entity defined as 

having a total electric output of 4 million megawatt-hours (MWhr) in the previous fiscal year. The specific SBA size standard 

is identified for each affected industry within the industry 

profile to support this economic analysis.

After considering the economic impacts of this proposed 

rule on small entities, I certify that this action will not have 

a significant economic impact on a substantial number of small 

entities. This certification is based on the economic impact of 
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this action to all affected small entities across all industries 

affected. The percentage of small entities impacted by this 

proposal having annualized costs of greater than 1 percent of 

their sales is less than 2 percent according to the small entity 

analysis. We conclude that there is no significant economic 

impact on a substantial number of small entities for this rule.

For more information on the small entity impacts associated 

with the rule, please refer to the Economic Impact and Small 

Business Analyses in the public docket. These analyses can be 

found in the RIA for each of the rules affected by this action.

Although the proposed reconsideration rule would not have a 

significant economic impact on a substantial number of small 

entities, EPA nonetheless tried to reduce the impact of the rule 

on small entities. When developing the revised standards, EPA 

took special steps to ensure that the burdens imposed on small 

entities were minimal. EPA conducted several meetings with 

industry trade associations to discuss regulatory options and 

the corresponding burden on industry, such as recordkeeping and 

reporting. In addition, as mentioned earlier in this preamble, 

EPA proposes to reduce regulatory requirements for a variety of 

area sources affected under each of the RICE rules with 

amendments to the final RICE rules promulgated in 2010. We 

continue to be interested in the potential impacts of this
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proposed rule on small entities and welcome comments on issues 

related to such impacts.

D. Unfunded Mandates Reform Act of 1995

This rule does not contain a federal mandate that may 

result in expenditures of $100 million or more for state, local, 

and tribal governments, in the aggregate, or the private sector 

in any one year. The EPA is proposing management practices for 

certain existing engines located at area sources and is 

proposing amendments that will provide owners and operators with

alternative and less expensive compliance demonstration methods. 

As a result of these proposed changes, the EPA anticipates a 

substantial reduction in the cost burden associated with this 

rule. Thus, this rule is not subject to the requirements of 

sections 202 or 205 of UMRA.

This rule is also not subject to the requirements of 

section 203 of UMRA because it contains no regulatory 

requirements that might significantly or uniquely affect small 

governments. The changes being proposed in this action by the 

agency will mostly affect stationary engine owners and operators 

and will not affect small governments. The proposed amendments 

will lead to a reduction in the cost burden.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will 

not have substantial direct effects on the states, on the 
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relationship between the national government and the states, or 

on the distribution of power and responsibilities among the 

various levels of government, as specified in Executive Order 

13132. This proposed action primarily affects private industry, 

and does not impose significant economic costs on state or local 

governments. Thus, Executive Order 13132 does not apply to this 

action. In the spirit of Executive Order 13132 and consistent 

with the EPA policy to promote communications between the EPA 

and state and local governments, the EPA specifically solicits 

comment on this proposed action from state and local officials.

F. Executive Order 13175: Consultation and Coordination with

Indian Tribal Governments

This action does not have tribal implications, as specified 

in Executive Order 13175 (65 FR 67249, November 9, 2000). It 

will not have substantial direct effects on tribal governments, 

on the relationship between the federal government and Indian 

tribes, or on the distribution of power and responsibilities 

between the federal government and Indian tribes, as specified 

in Executive Order 13175. Thus, Executive Order 13175 does not 

apply to this action. The EPA specifically solicits additional 

comment on this proposed action from tribal officials.

G. Executive Order 13045: Protection of Children from 

Environmental Health and Safety Risks
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The EPA interprets Executive Order 13045 (62 FR 19885, 

April 23, 1997) as applying only to those regulatory actions 

that are based on health or safety risks, such that the analysis 

required under section 5-501 of the Executive Order has the 

potential to influence the regulation. This action is not 

subject to Executive Order 13045 because it is based solely on 

technology performance.

H. Executive Order 13211: Actions Concerning Regulations that 

Significantly Affect Energy Supply, Distribution or Use

This action is not a “significant energy action” as defined 

in Executive Order 13211 (66 FR 28355 (May 22, 2001)), because 

it is not likely to have a significant adverse effect on the 

supply, distribution, or use of energy. This action reduces the 

burden of the rule on owners and operators of stationary engines 

by providing less burdensome compliance demonstration methods to 

owners and operators and greater flexibility in the operation of 

emergency engines. As a result of these proposed changes, the 

EPA anticipates a substantial reduction in the cost burden 

associated with this rule.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and 

Advancement Act of 1995 (“NTTAA”), Public Law No. 104-113, 12(d) 

(15 U.S.C. 272 note) directs EPA to use voluntary consensus 

standards in its regulatory activities unless to do so would be 
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inconsistent with applicable law or otherwise impractical. 

Voluntary consensus standards are technical standards (e.g., 

materials specifications, test methods, sampling procedures, and 

business practices) that are developed or adopted by voluntary 

consensus standards bodies. NTTAA directs EPA to provide 

Congress, through OMB, explanations when the agency decides not 

to use available and applicable voluntary consensus standards. 

This proposed rulemaking involves technical standards. The 

EPA proposes to use EPA Method 25A of 40 CFR part 60, appendix 

A. While the agency identified two voluntary consensus standards

as being potentially applicable, we do not propose to use it in 

this rulemaking. The two candidate voluntary consensus 

standards, ISO 14965:2000(E) and EN 12619 (1999), identified 

would not be practical due to lack of equivalency, 

documentation, validation data and other important technical and 

policy considerations. The search and review results have been 

documented and are placed in the docket for the proposed rule.

EPA welcomes comments on this aspect of the proposed 

rulemaking and, specifically, invites the public to identify 

potentially-applicable voluntary consensus standards and to 

explain why such standards should be used in this regulation.

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations
Page 94 of 200

Executive Order 12898 (59 FR 7629 (February 16, 1994)) 

establishes federal executive policy on environmental justice. 

Its main provision directs federal agencies, to the greatest 

extent practicable and permitted by law, to make environmental 

justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies and activities 

on minority populations and low-income populations in the United 

States.

 The EPA has concluded that it is not feasible to determine 

whether there would be disproportionately high and adverse human 

health or environmental effects on minority, low income or 

indigenous populations from the reconsideration of this final 

rule, as the EPA does not have specific information about the 

location of the stationary RICE affected by this rule. 
National Emission Standards for Hazardous Air Pollutants for 

Reciprocating Internal Combustion Engines; New Source 

Performance Standards for Stationary Internal Combustion Engines

Page 95 of 200

List of Subjects

40 CFR part 60

Administrative practice and procedure, Air pollution control, 

Incorporation by reference, Intergovernmental relations, 

Reporting and recordkeeping. 

40 CFR part 63

Administrative practice and procedure, Air pollution control, 

Hazardous substances, Incorporation by reference, 

Intergovernmental relations, Reporting and recordkeeping 

requirements.

______________________

Dated:

______________________

Lisa P. Jackson,

Administrator.
Page 96 of 200

For the reasons stated in the preamble, title 40, chapter I of 

the Code of Federal Regulations is amended as follows:

PART 60—[AMENDED]

1. The authority citation for part 60 continues to read as 

follows:

Authority: 42 U.S.C. 7401, et seq. 

Subpart IIII—[amended]

1. Section 60.4207 is amended by revising paragraph (b) to 

read as follows:

§60.4207 What fuel requirements must I meet if I am an owner or 

operator of a stationary CI internal combustion engine subject 

to this subpart?

* * * * *

(b) Beginning October 1, 2010, owners and operators of 

stationary CI ICE subject to this subpart with a displacement of 

less than 30 liters per cylinder that use diesel fuel must use 

diesel fuel that meets the requirements of 40 CFR 80.510(b) for 

nonroad diesel fuel, except that any existing diesel fuel 

purchased (or otherwise obtained) prior to October 1, 2010, may 

be used until depleted.

* * * * *

2. Section 60.4211 is amended by revising paragraph (f) to 

read as follows: 
Page 97 of 200

§60.4211 What are my compliance requirements if I am an owner 

or operator of a stationary CI internal combustion engine?

* * * * *

(f) If you own or operate an emergency stationary ICE, you 

must operate the emergency stationary ICE according to the 

requirements in paragraphs (f)(1) through (3) of this section. 

In order for the engine to be considered an emergency stationary 

ICE under this subpart, any operation other than emergency 

operation, maintenance and testing, emergency demand response, 

and operation in non-emergency situations for 50 hours per year, 

as described in paragraphs (f)(1) through (3) of this section, 

is prohibited. If you do not operate the engine according to the 

requirements in paragraphs (f)(1) through (3) of this section, 

the engine will not be considered an emergency engine under this 

subpart and must meet all requirements for non-emergency 

engines. An engine that exceeds the calendar year limitations on 

non-emergency operation will be considered a non-emergency 

engine and subject to the requirements for non-emergency engines 

for the remaining life of the engine.

(1) There is no time limit on the use of emergency 

stationary ICE in emergency situations.

(2) You may operate your emergency stationary ICE for any 

combination of the purposes specified in paragraphs (f)(2)(i) 

through (iii) of this section for a maximum of 100 hours per 
Page 98 of 200

calendar year. Any operation for non-emergency situations as 

allowed by paragraph (f)(3) of this section counts as part of 

the 100 hours per calendar year allowed by this paragraph 

(f)(2).

(i) Emergency stationary ICE may be operated for 

maintenance checks and readiness testing, provided that the 

tests are recommended by federal, state or local government, the 

manufacturer, the vendor, the regional transmission authority or 

equivalent balancing authority and transmission operator, or the 

insurance company associated with the engine. The owner or 

operator may petition the Administrator for approval of 

additional hours to be used for maintenance checks and readiness 

testing, but a petition is not required if the owner or operator 

maintains records indicating that federal, state, or local 

standards require maintenance and testing of emergency ICE 

beyond 100 hours per calendar year.

(ii) Emergency stationary ICE may be operated for emergency 

demand response for periods in which the regional transmission 

authority or equivalent balancing authority and transmission 

operator has declared an Energy Emergency Alert Level 2 (EEA 

Level 2) as defined in the North American Electric Reliability 

Corporation Reliability Standard EOP-002-3, Capacity and Energy 

Emergencies. 
Page 99 of 200

(iii) Emergency stationary ICE may be operated for periods 

where there is a deviation of voltage or frequency of 5 percent 

or greater below standard voltage or frequency.

(3) Emergency stationary ICE may be operated for up to 50 

hours per calendar year in non-emergency situations. The 50 

hours of operation in non-emergency situations are counted as 

part of the 100 hours per calendar year for maintenance and 

testing and emergency demand response provided in paragraph 

(f)(2) of this section. The 50 hours per year for non-emergency 

situations cannot be used for peak shaving or non-emergency 

demand response, or to otherwise supply power as part of a 

financial arrangement with another entity. 

* * * * *

3. Section 60.4219 is amended by revising the definition of 

“Emergency stationary internal combustion engine” to read as 

follows:

§60.4219 What definitions apply to this subpart?

* * * * *

Emergency stationary internal combustion engine means any 

stationary reciprocating internal combustion engine that meets 

all of the criteria in paragraphs (1) through (3) of this 

definition. All emergency stationary ICE must comply with the 

requirements specified in §60.4211(f) in order to be considered 

emergency stationary ICE. If the engine does not comply with the 
Page 100 of 200

requirements specified in §60.4211(f), then it is not considered 

to be an emergency stationary ICE under this subpart.

(1) The stationary ICE is operated to provide electrical 

power or mechanical work during an emergency situation. Examples 

include stationary ICE used to produce power for critical 

networks or equipment (including power supplied to portions of a 

facility) when electric power from the local utility (or the 

normal power source, if the facility runs on its own power 

production) is interrupted, or stationary ICE used to pump water 

in the case of fire or flood, etc.

(2) The stationary ICE is operated under limited 

circumstances for situations not included in paragraph (1) of 

this definition, as specified in §60.4211(f). 

(3) The stationary ICE operates as part of a financial 

arrangement with another entity in situations not included in 

paragraph (1) of this definition only as allowed in

§60.4211(f)(2)(ii) or (iii).

* * * * *

Subpart JJJJ—[amended]

4. Section 60.4231 is amended by revising paragraphs (b) 

through (d) to read as follows:

§60.4231 What emission standards must I meet if I am a 

manufacturer of stationary SI internal combustion engines or 

equipment containing such engines?
Page 101 of 200

* * * * *

(b) Stationary SI internal combustion engine manufacturers 

must certify their stationary SI ICE with a maximum engine power 

greater than 19 KW (25 HP) (except emergency stationary ICE with 

a maximum engine power greater than 25 HP and less than 130 HP) 

that use gasoline and that are manufactured on or after the 

applicable date in §60.4230(a)(2), or manufactured on or after 

the applicable date in §60.4230(a)(4) for emergency stationary 

ICE with a maximum engine power greater than or equal to 130 HP, 

to the certification emission standards and other requirements 

for new nonroad SI engines in 40 CFR part 1048. Stationary SI 

internal combustion engine manufacturers must certify their 

emergency stationary SI ICE greater than 25 HP and less than 130 

HP that use gasoline and that are manufactured on or after the 

applicable date in §60.4230(a)(4) to the Phase 1 emission 

standards in 40 CFR 90.103, applicable to class II engines, and 

other requirements for new nonroad SI engines in 40 CFR part 90. 

Stationary SI internal combustion engine manufacturers may 

certify their stationary SI ICE with a maximum engine power less 

than or equal to 30 KW (40 HP) with a total displacement less 

than or equal to 1,000 cubic centimeters (cc) that use gasoline 

to the certification emission standards and other requirements 

for new nonroad SI engines in 40 CFR part 90.
Page 102 of 200

(c) Stationary SI internal combustion engine manufacturers 

must certify their stationary SI ICE with a maximum engine power 

greater than 19 KW (25 HP) (except emergency stationary ICE with 

a maximum engine power greater than 25 HP and less than 130 HP) 

that are rich burn engines that use LPG and that are 

manufactured on or after the applicable date in §60.4230(a)(2) , 

or manufactured on or after the applicable date in 

§60.4230(a)(4) for emergency stationary ICE with a maximum 

engine power greater than or equal to 130 HP, to the 

certification emission standards and other requirements for new 

nonroad SI engines in 40 CFR part 1048. Stationary SI internal 

combustion engine manufacturers must certify their emergency 

stationary SI ICE greater than 25 HP and less than 130 HP that 

are rich burn engines that use LPG and that are manufactured on 

or after the applicable date in §60.4230(a)(4) to the Phase 1 

emission standards in 40 CFR 90.103, applicable to class II 

engines, and other requirements for new nonroad SI engines in 40 

CFR part 90. Stationary SI internal combustion engine 

manufacturers may certify their stationary SI ICE with a maximum 

engine power less than or equal to 30 KW (40 HP) with a total 

displacement less than or equal to 1,000 cc that are rich burn 

engines that use LPG to the certification emission standards and 

other requirements for new nonroad SI engines in 40 CFR part 90.
Page 103 of 200

(d) Stationary SI internal combustion engine manufacturers 

who choose to certify their stationary SI ICE with a maximum 

engine power greater than 19 KW (25 HP) and less than 75 KW (100 

HP) (except gasoline and rich burn engines that use LPG and 

emergency stationary ICE with a maximum engine power greater 

than 25 HP and less than 130 HP) under the voluntary 

manufacturer certification program described in this subpart 

must certify those engines to the certification emission 

standards for new nonroad SI engines in 40 CFR part 1048.

Stationary SI internal combustion engine manufacturers who

choose to certify their emergency stationary SI ICE greater than 

25 HP and less than 130 HP (except gasoline and rich burn 

engines that use LPG), must certify those engines to the Phase 1 

emission standards in 40 CFR 90.103, applicable to class II 

engines, for new nonroad SI engines in 40 CFR part 90. 

Stationary SI internal combustion engine manufacturers may 

certify their stationary SI ICE with a maximum engine power less 

than or equal to 30 KW (40 HP) with a total displacement less 

than or equal to 1,000 cc (except gasoline and rich burn engines 

that use LPG) to the certification emission standards for new 

nonroad SI engines in 40 CFR part 90. For stationary SI ICE with 

a maximum engine power greater than 19 KW (25 HP) and less than 

75 KW (100 HP) (except gasoline and rich burn engines that use 

LPG and emergency stationary ICE with a maximum engine power 
Page 104 of 200

greater than 25 HP and less than 130 HP) manufactured prior to 

January 1, 2011, manufacturers may choose to certify these 

engines to the standards in Table 1 to this subpart applicable 

to engines with a maximum engine power greater than or equal to 

100 HP and less than 500 HP.

* * * * *

5. Section 60.4243 is amended by revising paragraph (d) to 

read as follows: 

§60.4243 What are my compliance requirements if I am an owner 

or operator of a stationary SI internal combustion engine?

* * * * *

(d) If you own or operate an emergency stationary ICE, you 

must operate the emergency stationary ICE according to the 

requirements in paragraphs (d)(1) through (3) of this section. 

In order for the engine to be considered an emergency stationary 

ICE under this subpart, any operation other than emergency 

operation, maintenance and testing, emergency demand response, 

and operation in non-emergency situations for 50 hours per year, 

as described in paragraphs (d)(1) through (3) of this section, 

is prohibited. If you do not operate the engine according to the 

requirements in paragraphs (d)(1) through (3) of this section, 

the engine will not be considered an emergency engine under this 

subpart and must meet all requirements for non-emergency 

engines. An engine that exceeds the calendar year limitations on 
Page 105 of 200

non-emergency operation will be considered a non-emergency 

engine and subject to the requirements for non-emergency engines 

for the remaining life of the engine.

(1) There is no time limit on the use of emergency 

stationary ICE in emergency situations.

(2) You may operate your emergency stationary ICE for any 

combination of the purposes specified in paragraphs (d)(2)(i) 

through (iii) of this section for a maximum of 100 hours per 

calendar year. Any operation for non-emergency situations as 

allowed by paragraph (d)(3) of this section counts as part of 

the 100 hours per calendar year allowed by this paragraph 

(d)(2).

(i) Emergency stationary ICE may be operated for 

maintenance checks and readiness testing, provided that the 

tests are recommended by federal, state or local government, the 

manufacturer, the vendor, the regional transmission authority or 

equivalent balancing authority and transmission operator, or the 

insurance company associated with the engine. The owner or 

operator may petition the Administrator for approval of 

additional hours to be used for maintenance checks and readiness 

testing, but a petition is not required if the owner or operator 

maintains records indicating that federal, state, or local 

standards require maintenance and testing of emergency ICE 

beyond 100 hours per calendar year.
Page 106 of 200

(ii) Emergency stationary ICE may be operated for emergency 

demand response for periods in which the regional transmission 

authority or equivalent balancing authority and transmission 

operator has declared an Energy Emergency Alert Level 2 (EEA 

Level 2) as defined in the North American Electric Reliability 

Corporation Reliability Standard EOP-002-3, Capacity and Energy 

Emergencies. 

(iii) Emergency stationary ICE may be operated for periods 

where there is a deviation of voltage or frequency of 5 percent 

or greater below standard voltage or frequency.

(3) Emergency stationary ICE may be operated for up to 50 

hours per calendar year in non-emergency situations. The 50 

hours of operation in non-emergency situations are counted as 

part of the 100 hours per calendar year for maintenance and 

testing and emergency demand response provided in paragraph 

(d)(2) of this section. The 50 hours per year for non-emergency 

situations cannot be used for peak shaving or non-emergency 

demand response, or to otherwise supply power as part of a 

financial arrangement with another entity. 

* * * * *

6. Section 60.4248 is amended by revising the definition of 

“Emergency stationary internal combustion engine” to read as 

follows:

§60.4248 What definitions apply to this subpart?
Page 107 of 200

* * * * *

Emergency stationary internal combustion engine means any 

stationary reciprocating internal combustion engine that meets 

all of the criteria in paragraphs (1) through (3) of this 

definition. All emergency stationary ICE must comply with the 

requirements specified in §60.4243(d) in order to be considered 

emergency stationary ICE. If the engine does not comply with the 

requirements specified in §60.4243(d), then it is not considered 

to be an emergency stationary ICE under this subpart.

(1) The stationary ICE is operated to provide electrical 

power or mechanical work during an emergency situation. Examples 

include stationary ICE used to produce power for critical 

networks or equipment (including power supplied to portions of a 

facility) when electric power from the local utility (or the 

normal power source, if the facility runs on its own power 

production) is interrupted, or stationary ICE used to pump water 

in the case of fire or flood, etc.

(2) The stationary ICE is operated under limited

circumstances for situations not included in paragraph (1) of 

this definition, as specified in §60.4243(d). 

(3) The stationary ICE operates as part of a financial 

arrangement with another entity in situations not included in 

paragraph (1) of this definition only as allowed in 

§60.4243(d)(2)(ii) or (iii).
Page 108 of 200

* * * * *

7. Table 2 to Subpart JJJJ of Part 60 is revised to read as 

follows:

Table 2 to Subpart JJJJ of Part 60 –- Requirements for 

Performance Tests 

As stated in §60.4244, you must comply with the following 

requirements for performance tests within 10 percent of 100 

percent peak (or the highest achievable) load:

For each Complying 

with the 

requirement 

to

You must Using According 

to the 

following 

requirement

s

1. 

Stationary 

SI internal 

combustion 

engine 

demonstrati

ng 

compliance 

according 

to 

§60.4244.

a. limit 

the 

concentrati

on of NOx

in the 

stationary 

SI internal 

combustion 

engine 

exhaust

i. Select 

the 

sampling 

port 

location 

and the 

number of 

traverse 

points;

(1) Method 

1 or 1A of 

40 CFR part 

60, 

Appendix A 

or ASTM 

Method 

D6522-

00(2005)a.

(a) If 

using a 

control 

device, the 

sampling 

site must 

be located 

at the 

outlet of 

the control 

device.

ii. 

Determine 

the O2

concentrati

on of the 

stationary 

internal 

combustion 

engine 

exhaust at 

the 

sampling 

port 

location;

(2) Method 

3, 3A, or 

3Bb of 40 

CFR part 

60, 

appendix A 

or ASTM 

Method 

D6522-

00(2005)a.

(b) 

Measurement

s to 

determine 

O2

concentrati

on must be 

made at the 

same time 

as the 

measurement

s for NOx

concentrati

on.
Page 109 of 200

iii. If 

necessary, 

determine 

the exhaust 

flowrate of 

the 

stationary 

internal 

combustion 

engine 

exhaust;

(3) Method 

2 or 19 of 

40 CFR part 

60. 

iv. If 

necessary, 

measure 

moisture 

content of 

the 

stationary 

internal 

combustion 

engine 

exhaust at 

the 

sampling 

port 

location; 

and

(4) Method 

4 of 40 CFR 

part 60, 

appendix A, 

Method 320 

of 40 CFR 

part 63, 

appendix A, 

or ASTM D 

6348-03 

(incorporat

ed by 

reference, 

see 

§60.17).

(c) 

Measurement

s to 

determine 

moisture 

must be 

made at the 

same time 

as the

measurement

for NOx 

concentrati

on.

v. Measure 

NOx at the 

exhaust of 

the 

stationary 

internal 

combustion 

engine.

(5) Method 

7E of 40 

CFR part 

60, 

appendix A, 

Method 

D6522-

00(2005)a, 

Method 320 

of 40 CFR 

part 63, 

appendix A, 

or ASTM D 

6348-03 

(incorporat

ed by 

reference, 

see 

§60.17).

(d) Results 

of this 

test 

consist of 

the average 

of the 

three 1-

hour or 

longer 

runs.
Page 110 of 200

b. limit 

the 

concentrati

on of CO in 

the 

stationary 

SI internal 

combustion 

engine 

exhaust

i. Select 

the 

sampling 

port 

location 

and the 

number of 

traverse 

points;

(1) Method 

1 or 1A of 

40 CFR part 

60, 

Appendix A 

or ASTM 

Method 

D6522-

00(2005)a. 

(a) If 

using a 

control 

device, the 

sampling 

site must 

be located 

at the 

outlet of 

the control 

device.

ii. 

Determine 

the O2

concentrati

on of the 

stationary 

internal 

combustion 

engine 

exhaust at 

the 

sampling 

port 

location;

(2) Method 

3, 3A, or 

3Bb of 40 

CFR part 

60, 

appendix A 

or ASTM 

Method 

D6522-

00(2005)a.

(b) 

Measurement

s to 

determine 

O2

concentrati

on must be 

made at the 

same time 

as the 

measurement

s for CO 

concentrati

on.

iii. If 

necessary, 

determine 

the exhaust 

flowrate of 

the 

stationary 

internal 

combustion 

engine 

exhaust;

(3) Method 

2 or 19 of 

40 CFR part 

60. 
Page 111 of 200

iv. If 

necessary, 

measure 

moisture 

content of 

the 

stationary 

internal 

combustion 

engine 

exhaust at 

the 

sampling 

port 

location; 

and

(4) Method 

4 of 40 CFR 

part 60, 

appendix A, 

Method 320 

of 40 CFR 

part 63, 

appendix A, 

or ASTM D 

6348-03 

(incorporat

ed by 

reference, 

see 

§60.17).

(c) 

Measurement

s to 

determine

moisture 

must be 

made at the 

same time 

as the 

measurement

for CO 

concentrati

on.

v. Measure 

CO at the 

exhaust of 

the 

stationary 

internal 

combustion 

engine.

(5) Method 

10 of 40 

CFR part 

60, 

appendix A, 

ASTM Method 

D6522-

00(2005)a, 

Method 320 

of 40 CFR 

part 63, 

appendix A, 

or ASTM D 

6348-03 

(incorporat

ed by 

reference, 

see 

§60.17).

(d) Results 

of this 

test 

consist of 

the average 

of the 

three 1-

hour or 

longer 

runs.

c. limit 

the 

concentrati

on of VOC 

in the 

stationary 

SI internal 

combustion 

engine 

exhaust

i. Select 

the 

sampling 

port 

location 

and the 

number of 

traverse 

points;

(1) Method 

1 or 1A of 

40 CFR part 

60, 

Appendix A.

(a) If 

using a 

control 

device, the 

sampling 

site must 

be located 

at the 

outlet of 

the control 

device.
Page 112 of 200

ii. 

Determine 

the O2

concentrati

on of the 

stationary 

internal 

combustion 

engine 

exhaust at 

the 

sampling 

port 

location;

(2) Method 

3, 3A, or 

3Bb of 40 

CFR part 

60, 

appendix A 

or ASTM 

Method 

D6522-

00(2005) a.

(b) 

Measurement

s to 

determine 

O2

concentrati

on must be 

made at the 

same time 

as the 

measurement

s for VOC 

concentrati

on.

iii. If 

necessary, 

determine 

the exhaust 

flowrate of 

the 

stationary 

internal 

combustion 

engine 

exhaust;

(3) Method 

2 or 19 of 

40 CFR part 

60. 

iv. If 

necessary, 

measure 

moisture 

content of 

the 

stationary 

internal 

combustion 

engine 

exhaust at 

the 

sampling 

port 

location; 

and

(4) Method 

4 of 40 CFR 

part 60, 

appendix A, 

Method 320 

of 40 CFR 

part 63, 

appendix A, 

or ASTM D 

6348-03 

(incorporat

ed by 

reference, 

see 

§60.17).

(c) 

Measurement

s to 

determine

moisture 

must be 

made at the 

same time 

as the 

measurement

for VOC 

concentrati

on.
Page 113 of 200

v. Measure 

VOC at the 

exhaust of 

the 

stationary 

internal 

combustion 

engine.

(5) 

Methods 25A 

and 18 of 

40 CFR part 

60, 

appendix A, 

Method 25A 

with the 

use of a 

methane 

cutter as 

described 

in 40 CFR 

1065.265, 

Method 18 

or 40 CFR 

part 60, 

appendix 

A

c,d, Method 

320 of 40 

CFR part 

63, 

appendix A, 

or ASTM D 

6348-03 

(incorporat

ed by 

reference, 

see 

§60.17).

(d) Results 

of this 

test 

consist of 

the average 

of the 

three 1-

hour or 

longer 

runs.

a ASTM D6522-00 is incorporated by reference; see 40 CFR 60.17. 

Also, you may petition the Administrator for approval to use 

alternative methods for portable analyzer.

b You may use ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses, 

for measuring the O2 content of the exhaust gas as an alternative 

to EPA Method 3B. 

c You may use EPA Method 18 of 40 CFR part 60, appendix A, 

provided that you conduct an adequate presurvey test prior to 

the emissions test, such as the one described in OTM 11 on EPA’s

website (http://www.epa.gov/ttn/emc/prelim/otm11.pdf).

d You may use ASTM D6420-99 (2004), Test Method for Determination 

of Gaseous Organic Compounds by Direct Interface Gas 

Chromatography/Mass Spectrometry as an alternative to EPA Method 

18 for measuring total nonmethane organic.

PART 63--[AMENDED]
Page 114 of 200

8. The authority citation for part 63 continues to read as 

follows:

Authority: 42 U.S.C. 7401, et seq. 

Subpart ZZZZ--[amended]

9. Section 63.6585 is amended by adding paragraph (f) to 

read as follows:

§63.6585 Am I subject to this subpart?

* * * * *

(f) The emergency stationary RICE listed in paragraphs 

(f)(1) through (3) of this section are not subject to this 

subpart. The stationary RICE must meet the definition of an 

emergency stationary RICE in §63.6675, which includes operating 

according to the provisions specified in §63.6640(f). 

(1) Existing residential emergency stationary RICE located 

at an area source of HAP emissions.

(2) Existing commercial emergency stationary RICE located 

at an area source of HAP emissions.

(3) Existing institutional emergency stationary RICE 

located at an area source of HAP emissions.

10. Section 63.6590 is amended by removing paragraphs 

(b)(3)(vi) through (viii).

11. Section 63.6595 is amended by revising paragraph (a)(1)

to read as follows:

§63.6595 When do I have to comply with this subpart?
Page 115 of 200

(a) * * *

(1) If you have an existing stationary RICE, excluding 

existing non-emergency CI stationary RICE, with a site rating of 

more than 500 brake HP located at a major source of HAP 

emissions, you must comply with the applicable emission 

limitations, operating limitations and other requirements no 

later than June 15, 2007. If you have an existing non-emergency 

CI stationary RICE with a site rating of more than 500 brake HP 

located at a major source of HAP emissions, an existing 

stationary CI RICE with a site rating of less than or equal to 

500 brake HP located at a major source of HAP emissions, or an 

existing stationary CI RICE located at an area source of HAP 

emissions, you must comply with the applicable emission 

limitations, operating limitations, and other requirements no 

later than May 3, 2013. If you have an existing stationary SI 

RICE with a site rating of less than or equal to 500 brake HP 

located at a major source of HAP emissions, or an existing 

stationary SI RICE located at an area source of HAP emissions,

you must comply with the applicable emission limitations, 

operating limitations, and other requirements no later than 

October 19, 2013.

* * * * *

12. Section 63.6602 is revised to read as follows: 
Page 116 of 200

§63.6602 What emission limitations and other requirements must 

I meet if I own or operate an existing stationary RICE with a 

site rating of equal to or less than 500 brake HP located at a 

major source of HAP emissions?

If you own or operate an existing stationary RICE with a 

site rating of equal to or less than 500 brake HP located at a 

major source of HAP emissions, you must comply with the emission 

limitations and other requirements in Table 2c to this subpart 

which apply to you. Compliance with the numerical emission 

limitations established in this subpart is based on the results 

of testing the average of three 1-hour runs using the testing 

requirements and procedures in §63.6620 and Table 4 to this 

subpart.

13. Section 63.6603 is amended by:

a. Revising the section heading;

b. Revising paragraph (b); and

c. Adding paragraphs (c) through (e) to read as follows:

§63.6603 What emission limitations, operating limitations, and 

other requirements must I meet if I own or operate an existing 

stationary RICE located at an area source of HAP emissions?

* * * * *

(b) If you own or operate an existing stationary nonemergency CI RICE with a site rating of more than 300 HP located 

at an area source of HAP that meets either paragraph (b)(1) or 
Page 117 of 200

(b)(2) of this section, you do not have to meet the numerical CO 

emission limitations specified in Table 2d of this subpart. 

Existing stationary non-emergency CI RICE with a site rating of 

more than 300 HP located at an area source of HAP that meet 

either paragraph (b)(1) or (b)(2) of this section must meet the 

management practices that are shown for stationary non-emergency 

CI RICE with a site rating of less than or equal to 300 HP in 

Table 2d of this subpart.

(1) The area source is located in an area of Alaska that is 

not accessible by the Federal Aid Highway System (FAHS).

(2) The stationary RICE is located at an area source that 

meets paragraphs (b)(2)(i), (b)(2)(ii), and (b)(2)(iii) of this 

section.

(i) The only connection to the FAHS is through the Alaska 

Marine Highway System (AMHS), or the stationary RICE operation 

is within an isolated grid in Alaska that is not connected to 

the statewide electrical grid referred to as the Alaska Railbelt 

Grid.

(ii) At least 10 percent of the power generated by the 

stationary RICE on an annual basis is used for residential 

purposes.

(iii) The generating capacity of the area source is less 

than 12 megawatts, or the stationary RICE is used exclusively 
Page 118 of 200

for backup power for renewable energy and is used less than 500 

hrs per year on a 10 year rolling average.

(c) If you own or operate an existing non-emergency CI RICE 

with a site rating of more than 300 HP located at an area source 

of HAP emissions that is certified to the Tier 1 or Tier 2 

emission standards in Table 1 of 40 CFR 89.112 and that is 

subject to an enforceable state or local standard that requires 

the engine to be replaced no later than June 1, 2018, you may 

until January 1, 2015, or 12 years after the installation date

of the engine (whichever is later), but not later than June 1, 

2018, choose to comply with the management practices that are 

shown for stationary non-emergency CI RICE with a site rating of 

less than or equal to 300 HP in Table 2d of this subpart instead 

of the applicable emission limitations in Table 2d, operating 

limitations in Table 2b, and crankcase ventilation system 

requirements in §63.6625(g). You must comply with the emission 

limitations in Table 2d and operating limitations in Table 2b 

that apply for non-emergency CI RICE with a site rating of more 

than 300 HP located at an area source of HAP emissions by 

January 1, 2015, or 12 years after the installation date of the 

engine (whichever is later), but not later than June 1, 2018. 

You must also comply with the crankcase ventilation system 

requirements in §63.6625(g) by January 1, 2015, or 12 years 
Page 119 of 200

after the installation date of the engine (whichever is later), 

but not later than June 1, 2018.

(d) If you own or operate an existing non-emergency CI RICE 

with a site rating of more than 300 HP located at an area source 

of HAP emissions that is certified to the Tier 3 (Tier 2 for 

engines above 560 kW) emission standards in Table 1 of 40 CFR 

89.112, you may comply with the requirements under this part by 

meeting the requirements for Tier 3 engines (Tier 2 for engines 

above 560 kW) in 40 CFR part 60 subpart IIII instead of the 

emission limitations and other requirements that would otherwise 

apply under this part for existing non-emergency CI RICE with a 

site rating of more than 300 HP located at an area source of HAP 

emissions.

(e) An existing non-emergency SI 4SLB and 4SRB stationary 

RICE with a site rating of more than 500 HP located at area 

sources of HAP must meet the definition of remote stationary 

RICE in §63.6675 on the initial compliance date for the engine, 

October 19, 2013, in order to be considered a remote stationary 

RICE under this subpart. Owners and operators of existing nonemergency SI 4SLB and 4SRB stationary RICE with a site rating of 

more than 500 HP located at area sources of HAP that meet the 

definition of remote stationary RICE in §63.6675 of this subpart

as of October 19, 2013 must evaluate the status of their 

stationary RICE every 12 months. Owners and operators must keep 
Page 120 of 200

records of the initial and annual evaluation of the status of 

the engine. If the evaluation indicates that the stationary RICE 

no longer meets the definition of remote stationary RICE in 

§63.6675 of this subpart, the owner or operator must comply with 

all of the requirements for existing non-emergency SI 4SLB and 

4SRB stationary RICE with a site rating of more than 500 HP 

located at area sources of HAP that are not remote stationary 

RICE within one year of the evaluation.

14. Section 63.6604 is revised to read as follows: 

§63.6604 What fuel requirements must I meet if I own or operate 

an existing stationary CI RICE?

If you own or operate an existing non-emergency, non-black 

start CI stationary RICE with a site rating of more than 300 

brake HP with a displacement of less than 30 liters per cylinder

that uses diesel fuel, you must use diesel fuel that meets the 

requirements in 40 CFR 80.510(b) for nonroad diesel fuel. 

Existing non-emergency CI stationary RICE located in Guam, 

American Samoa, the Commonwealth of the Northern Mariana 

Islands, or at area sources in areas of Alaska that meet either 

§63.6603(b)(1) or §63.6603(b)(2) are exempt from the 

requirements of this section.

15. Section 63.6605 is amended by revising paragraph (a) to 

read as follows:
Page 121 of 200

§63.6605 What are my general requirements for complying with 

this subpart?

(a) You must be in compliance with the emission 

limitations, operating limitations, and other requirements in 

this subpart that apply to you at all times.

* * * * *

16. Section 63.6620 is amended by revising paragraphs (b) 

and (e) to read as follows:

§63.6620 What performance tests and other procedures must I 

use?

* * * * *

(b) Each performance test must be conducted according to 

the requirements that this subpart specifies in Table 4 to this 

subpart. If you own or operate a non-operational stationary RICE 

that is subject to performance testing, you do not need to start 

up the engine solely to conduct the performance test. Owners and 

operators of a non-operational engine can conduct the 

performance test when the engine is started up again. The test 

must be conducted at any load condition within plus or minus 10 

percent of 100 percent load for the stationary RICE listed in 

paragraphs (b)(1) through (4) of this section.

(1) Non-emergency 4SRB stationary RICE with a site rating 

of greater than 500 brake HP located at a major source of HAP 

emissions.
Page 122 of 200

(2) New non-emergency 4SLB stationary RICE with a site 

rating of greater than or equal to 250 brake HP located at a 

major source of HAP emissions.

(3) New non-emergency 2SLB stationary RICE with a site 

rating of greater than 500 brake HP located at a major source of 

HAP emissions.

(4) New non-emergency CI stationary RICE with a site rating 

of greater than 500 brake HP located at a major source of HAP 

emissions. 

* * * * *

(e)(1) You must use Equation 1 of this section to 

determine compliance with the percent reduction requirement:

Where:

Ci = concentration of CO, THC, or formaldehyde at the 

control device inlet,

Co = concentration of CO, THC, or formaldehyde at the 

control device outlet, and

R = percent reduction of CO, THC, or formaldehyde 

emissions.

(2) You must normalize the carbon monoxide (CO), total 

hydrocarbons (THC), or formaldehyde concentrations at the inlet 

and outlet of the control device to a dry basis and to 15 

percent oxygen, or an equivalent percent carbon dioxide (CO2). If 

Ci-Co

Ci

x 100 = R (Eq. 1)
Page 123 of 200

pollutant concentrations are to be corrected to 15 percent 

oxygen and CO2 concentration is measured in lieu of oxygen 

concentration measurement, a CO2 correction factor is needed. 

Calculate the CO2 correction factor as described in paragraphs 

(e)(2)(i) through (iii) of this section. 

(i) Calculate the fuel-specific Fo value for the fuel 

burned during the test using values obtained from Method 19, 

Section 5.2, and the following equation: 

Where:

Fo = Fuel factor based on the ratio of oxygen volume to the 

ultimate CO2 volume produced by the fuel at zero 

percent excess air.

0.209 = Fraction of air that is oxygen, percent/100.

 Fd = Ratio of the volume of dry effluent gas to the gross 

calorific value of the fuel from Method 19, dsm3/J 

(dscf/106 Btu).

Fc = Ratio of the volume of CO2 produced to the gross 

calorific value of the fuel from Method 19, dsm3/J 

(dscf/106 Btu)

(ii) Calculate the CO2 correction factor for correcting 

measurement data to 15 percent oxygen, as follows:

Where:

Xco2 = CO2 correction factor, percent.

5.9 = 20.9 percent O2 - 15 percent O2, the defined O2

correction value, percent.

Fo= 

0.209 Fd

Fc

 (Eq. 2)

XCO2 = 

5.9

Fo

 (Eq. 3)
Page 124 of 200

(iii) Calculate the CO, THC, and formaldehyde gas 

concentrations adjusted to 15 percent O2 using CO2 as follows:

Where:

%CO2 = Measured CO2 concentration measured, dry basis, percent.

* * * * *

17. Section 63.6625 is amended by:

a. Revising the first sentence in paragraph (a);

b. Revising the first sentence in paragraph (b);

c. Revising paragraph (e)(6); and

d. Revising paragraph (g) to read as follows:

§63.6625 What are my monitoring, installation, collection, 

operation, and maintenance requirements?

(a) If you elect to install a CEMS as specified in Table 5 

of this subpart, you must install, operate, and maintain a CEMS 

to monitor CO and either oxygen or CO2 according to the 

requirements in paragraphs (a)(1) through (4) of this section. 

If you are meeting a requirement to reduce CO emissions, the 

CEMS must be installed at both the inlet and outlet of the 

control device. If you are meeting a requirement to limit the 

concentration of CO, the CEMS must be installed at the outlet of 

the control device. * * *

Cadj = Cd

XCO2

%CO2

 (Eq. 4)
Page 125 of 200

* * * * *

(b) If you are required to install a continuous parameter 

monitoring system (CPMS) as specified in Table 5 of this 

subpart, you must install, operate, and maintain each CPMS 

according to the requirements in paragraphs (b)(1) through (6) 

of this section. * * *

* * * * *

(e) * * *

(6) An existing non-emergency, non-black start stationary 

RICE located at an area source of HAP emissions which combusts 

landfill or digester gas equivalent to 10 percent or more of the 

gross heat input on an annual basis;

* * * * *

(g) If you own or operate an existing non-emergency, non-black 

start CI engine greater than or equal to 300 HP that is not 

equipped with a closed crankcase ventilation system, you must 

comply with either paragraph (g)(1) or paragraph (g)(2) of this 

section. Owners and operators must follow the manufacturer’s 

specified maintenance requirements for operating and maintaining 

the open or closed crankcase ventilation systems and replacing 

the crankcase filters, or can request the Administrator to 

approve different maintenance requirements that are as 

protective as manufacturer requirements. Existing CI engines 

located at area sources in areas of Alaska that meet either 
Page 126 of 200

§63.6603(b)(1) or §63.6603(b)(2) do not have to meet the 

requirements of paragraph (g) of this section.

(1) Install a closed crankcase ventilation system that 

prevents crankcase emissions from being emitted to the 

atmosphere, or

(2) Install an open crankcase filtration emission control 

system that reduces emissions from the crankcase by filtering 

the exhaust stream to remove oil mist, particulates and metals.

* * * * *

18. Section 63.6630 is amended by:

a. Revising the section heading;

b. Revising paragraph (a); 

c. Adding paragraph (d); and

d. Adding paragraph (e) to read as follows:

§63.6630 How do I demonstrate initial compliance with the 

emission limitations, operating limitations, and other 

requirements?

(a) You must demonstrate initial compliance with each 

emission limitation, operating limitation, and other requirement 

that applies to you according to Table 5 of this subpart.

* * * * *

(d) Non-emergency 4SRB stationary RICE complying with the 

requirement to reduce formaldehyde emissions by 76 percent or 

more can demonstrate initial compliance with the formaldehyde 
Page 127 of 200

emission limit by testing for THC instead of formaldehyde. The 

testing must be conducted according to the requirements in Table 

4 of this subpart. The average reduction of emissions of THC 

determined from the performance test must be equal to or greater 

than 30 percent.

(e) The initial compliance demonstration required for 

existing non-emergency 4SLB and 4SRB stationary RICE with a site 

rating of more than 500 HP located at an area source of HAP that 

are not remote stationary RICE and that are operated more than 

24 hours per calendar year must be conducted according to the 

following requirements:

(1) The compliance demonstration must consist of at least 

three test runs.

(2) Each test run must be of at least 15 minute duration, 

except that each test conducted using the method in appendix A 

to this subpart must consist of at least one measurement cycle 

and include at least 2 minutes of test data phase measurement.

(3) If you are demonstrating compliance with the CO 

concentration or CO percent reduction requirement, you must 

measure CO emissions using one of the CO measurement methods 

specified in Table 4 of this subpart, or using appendix A to 

this subpart.
Page 128 of 200

(4) If you are demonstrating compliance with the THC 

percent reduction requirement, you must measure THC emissions 

using Method 25A of 40 CFR part 60, appendix A.

(5) You must measure O2 using one of the O2 measurement 

methods specified in Table 4 of this subpart. Measurements to 

determine O2 concentration must be made at the same time as the 

measurements for CO or THC concentration.

(6) If you are demonstrating compliance with the CO or THC 

percent reduction requirement, you must measure CO or THC 

emissions and O2 emissions simultaneously at the inlet and outlet 

of the control device.

19. Section 63.6640 is amended by:

a. Amending the section heading;

b. Revising paragraph (a); 

c. Revising paragraph (c); and 

d. Revising paragraph (f) to read as follows:

§63.6640 How do I demonstrate continuous compliance with the 

emission limitations, operating limitations, and other 

requirements?

(a) You must demonstrate continuous compliance with each 

emission limitation, operating limitation, and other 

requirements in Tables 1a and 1b, Tables 2a and 2b, Table 2c, 

and Table 2d to this subpart that apply to you according to 

methods specified in Table 6 to this subpart.
Page 129 of 200

* * * * *

(c) The annual compliance demonstration required for 

existing non-emergency 4SLB and 4SRB stationary RICE with a site 

rating of more than 500 HP located at an area source of HAP that 

are not remote stationary RICE and that are operated more than 

24 hours per calendar year must be conducted according to the 

following requirements:

(1) The compliance demonstration must consist of at least 

one test run.

(2) Each test run must be of at least 15 minute duration, 

except that each test conducted using the method in appendix A 

to this subpart must consist of at least one measurement cycle 

and include at least 2 minutes of test data phase measurement.

(3) If you are demonstrating compliance with the CO 

concentration or CO percent reduction requirement, you must 

measure CO emissions using one of the CO measurement methods 

specified in Table 4 of this subpart, or using appendix A to 

this subpart.

(4) If you are demonstrating compliance with the THC 

percent reduction requirement, you must measure THC emissions 

using Method 25A of 40 CFR part 60, appendix A.

(5) You must measure O2 using one of the O2 measurement 

methods specified in Table 4 of this subpart. Measurements to 
Page 130 of 200

determine O2 concentration must be made at the same time as the 

measurements for CO or THC concentration.

(6) If you are demonstrating compliance with the CO or THC 

percent reduction requirement, you must measure CO or THC 

emissions and O2 emissions simultaneously at the inlet and outlet 

of the control device.

(7) If the results of the annual compliance demonstration 

show that the emissions exceed the levels specified in Table 6 

of this subpart, the stationary RICE must be shut down as soon 

as safely possible, and appropriate corrective action must be 

taken (e.g., repairs, catalyst cleaning, catalyst replacement). 

The stationary RICE must be retested within 7 days of being 

restarted and the emissions must meet the levels specified in 

Table 6 of this subpart. If the retest shows that the emissions 

continue to exceed the specified levels, the stationary RICE 

must again be shut down as soon as safely possible, and the 

stationary RICE may not operate, except for purposes of startup 

and testing, until the owner/operator demonstrates through 

testing that the emissions do not exceed the levels specified in 

Table 6 of this subpart.

* * * * *

(f) If you own or operate an emergency stationary RICE, you 

must operate the emergency stationary RICE according to the 

requirements in paragraphs (f)(1) through (4) of this section. 
Page 131 of 200

In order for the engine to be considered an emergency stationary 

RICE under this subpart, any operation other than emergency 

operation, maintenance and testing, emergency demand response, 

and operation in non-emergency situations for 50 hours per year, 

as described in paragraphs (f)(1) through (4) of this section, 

is prohibited. If you do not operate the engine according to the 

requirements in paragraphs (f)(1) through (4) of this section, 

the engine will not be considered an emergency engine under this 

subpart and must meet all requirements for non-emergency 

engines. An engine that exceeds the calendar year limitations on 

non-emergency operation will be considered a non-emergency 

engine and subject to the requirements for non-emergency engines 

for the remaining life of the engine.

(1) There is no time limit on the use of emergency 

stationary RICE in emergency situations.

(2) You may operate your emergency stationary RICE for any 

combination of the purposes specified in paragraphs (f)(2)(i) 

through (iii) of this section for a maximum of 100 hours per 

calendar year. Any operation for non-emergency situations as 

allowed by paragraphs (f)(3) and (4) of this section counts as 

part of the 100 hours per calendar year allowed by this 

paragraph (f)(2).

(i) Emergency stationary RICE may be operated for 

maintenance checks and readiness testing, provided that the 
Page 132 of 200

tests are recommended by federal, state or local government, the 

manufacturer, the vendor, the regional transmission authority or 

equivalent balancing authority and transmission operator, or the 

insurance company associated with the engine. The owner or 

operator may petition the Administrator for approval of 

additional hours to be used for maintenance checks and readiness 

testing, but a petition is not required if the owner or operator 

maintains records indicating that federal, state, or local 

standards require maintenance and testing of emergency RICE 

beyond 100 hours per calendar year.

(ii) Emergency stationary RICE may be operated for 

emergency demand response for periods in which the regional 

transmission authority or equivalent balancing authority and 

transmission operator has declared an Energy Emergency Alert 

Level 2 (EEA Level 2) as defined in the North American Electric 

Reliability Corporation Reliability Standard EOP-002-3, Capacity 

and Energy Emergencies. 

(iii) Emergency stationary RICE may be operated for periods 

where there is a deviation of voltage or frequency of 5 percent 

or greater below standard voltage or frequency.

(3) Emergency stationary RICE located at major sources of 

HAP may be operated for up to 50 hours per calendar year in nonemergency situations. The 50 hours of operation in non-emergency 

situations are counted as part of the 100 hours per calendar 
Page 133 of 200

year for maintenance and testing and emergency demand response 

provided in paragraph (f)(2) of this section. The 50 hours per 

year for non-emergency situations cannot be used for peak 

shaving or non-emergency demand response, 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. 

(4) Existing emergency stationary RICE located at area 

sources of HAP may be operated for up to 50 hours per calendar 

year in non-emergency situations. The 50 hours of operation in 

non-emergency situations are counted as part of the 100 hours 

per calendar year for maintenance and testing and emergency 

demand response provided in paragraph (f)(2) of this section. 

(i) Prior to April 16, 2017, the 50 hours per year for nonemergency situations can be used for peak shaving or nonemergency demand response to generate income for a facility, or 

to otherwise supply power as part of a financial arrangement 

with another entity if engines is operated as part of a peak 

shaving (load management program) with the local distribution 

system operator and the power is provided only to the facility 

itself or to support the local distribution system.

(ii) On or after April 16, 2017, the 50 hours per year for

non-emergency situations cannot be used for peak shaving or non-
Page 134 of 200

emergency demand response, or to otherwise supply power as part 

of a financial arrangement with another entity.

* * * * *

20. Section 63.6645 is amended by adding a new paragraph 

(i) to read as follows:

§63.6645 What notifications must I submit and when?

* * * * *

(i) If you own or operate an existing non-emergency CI RICE 

with a site rating of more than 300 HP located at an area source 

of HAP emissions that is certified to the Tier 1 or Tier 2 

emission standards in Table 1 of 40 CFR 89.112 and subject to an 

enforceable state or local standard requiring engine replacement 

and you intend to meet management practices rather than emission 

limits, as specified in §63.6603(c), you must submit a 

notification by March 3, 2013, stating that you intend to use 

the provision in §63.6603(c) and identifying the state or local 

regulation that the engine is subject to.

21. Section 63.6675 is amended by: 

a. Adding in alphabetical order the definition of Alaska 

Railbelt Grid;

b. Revising the definition of Emergency stationary RICE; 

and 

c. Adding in alphabetical order the definition of Remote

stationary RICE to read as follows.
Page 135 of 200

§63.6675 What definitions apply to this subpart?

Alaska Railbelt Grid means the service areas of the six 

regulated public utilities that extend from Fairbanks to 

Anchorage and the Kenai Peninsula. These utilities are Golden 

Valley Electric Association; Chugach Electric Association;

Matanuska Electric Association; Homer Electric Association; 

Anchorage Municipal Light & Power; and the City of Seward 

Electric System.

* * * * *

Emergency stationary RICE means any stationary 

reciprocating internal combustion engine that meets all of the 

criteria in paragraphs (1) through (3) of this definition. All 

emergency stationary RICE must comply with the requirements 

specified in §63.6640(f) in order to be considered emergency 

stationary RICE. If the engine does not comply with the 

requirements specified in §63.6640(f), then it is not considered 

to be an emergency stationary RICE under this subpart.

(1) The stationary RICE is operated to provide electrical 

power or mechanical work during an emergency situation. Examples 

include stationary RICE used to produce power for critical 

networks or equipment (including power supplied to portions of a 

facility) when electric power from the local utility (or the 

normal power source, if the facility runs on its own power 
Page 136 of 200

production) is interrupted, or stationary RICE used to pump 

water in the case of fire or flood, etc.

(2) The stationary RICE is operated under limited 

circumstances for situations not included in paragraph (1) of 

this definition, as specified in §63.6640(f). 

(3) The stationary RICE operates as part of a financial 

arrangement with another entity in situations not included in 

paragraph (1) of this definition only as allowed in

§63.6640(f)(2)(ii) or (iii) and §63.6640(f)(4)(i).

* * * * *

Remote stationary RICE means stationary RICE meeting any of 

the following criteria: 

(1) Stationary RICE located in an offshore area that is 

beyond the line of ordinary low water along that portion of the 

coast of the United States that is in direct contact with the 

open seas and beyond the line marking the seaward limit of 

inland waters.

(2) Stationary RICE located on a pipeline segment that 

meets both of the criteria in paragraphs (2)(i) and (ii) of this 

definition.

(i) A pipeline segment with 10 or fewer buildings intended 

for human occupancy within 220 yards (200 meters) on either side 

of the centerline of any continuous 1-mile (1.6 kilometers) 

length of pipeline. Each separate dwelling unit in a multiple 
Page 137 of 200

dwelling unit building is counted as a separate building 

intended for human occupancy.

(ii) The pipeline segment does not lie within 100 yards (91 

meters) of either a building or a small, well-defined outside 

area (such as a playground, recreation area, outdoor theater, or 

other place of public assembly) that is occupied by 20 or more 

persons on at least 5 days a week for 10 weeks in any 12-month 

period. The days and weeks need not be consecutive. The building 

or area is considered occupied for a full day if it is occupied 

for any portion of the day. 

(iii) For purposes of this paragraph (2), the term pipeline 

segment means all parts of those physical facilities through 

which gas moves in transportation, including but not limited to 

pipe, valves, and other appurtenance attached to pipe, 

compressor units, metering stations, regulator stations, 

delivery stations, holders, and fabricated assemblies. 

Stationary RICE located within 50 yards (46 m) of the pipeline 

segment providing power for equipment on a pipeline segment are 

part of the pipeline segment. Transportation of gas means the 

gathering, transmission, or distribution of gas by pipeline, or 

the storage of gas. A building is intended for human occupancy 

if its primary use is for a purpose involving the presence of 

humans.
Page 138 of 200

(3) Stationary RICE that are not located on gas pipelines 

and that have 5 or fewer buildings intended for human occupancy 

within a 0.25 mile radius around the engine. A building is 

intended for human occupancy if its primary use is for a purpose 

involving the presence of humans.

* * * * *

22. Table 1b to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 1b to Subpart ZZZZ of Part 63. Operating Limitations for 

Existing, New, and Reconstructed SI 4SRB Stationary RICE >500 HP 

Located at a Major Source of HAP Emissions 

As stated in §§63.6600, 63.6603, 63.6630 and 63.6640, you must 

comply with the following operating limitations for existing, 

new and reconstructed 4SRB stationary RICE >500 HP located at a 

major source of HAP emissions:

For each... You must meet the following 

operating limitation, except 

during periods of startup...

1. existing, new and 

reconstructed 4SRB stationary 

RICE >500 HP located at a major 

source of HAP emissions

complying with the requirement 

to reduce formaldehyde 

emissions by 76 percent or more 

(or by 75 percent or more, if 

applicable) and using NSCR; 

or 

existing, new and reconstructed 

4SRB stationary RICE >500 HP 

located at a major source of 

HAP emissions complying with 

the requirement to limit the 

concentration of formaldehyde 

in the stationary RICE exhaust 

a. maintain your catalyst so 

that the pressure drop across 

the catalyst does not change by 

more than 2 inches of water at 

100 percent load plus or minus 

10 percent from the pressure 

drop across the catalyst 

measured during the initial 

performance test; and

b. maintain the temperature of 

your stationary RICE exhaust so 

that the catalyst inlet 

temperature is greater than or 

equal to 750°F and less than or 

equal to 1250°F.1
Page 139 of 200

to 350 ppbvd or less at 15 

percent O2 and using NSCR;

2. existing, new and 

reconstructed 4SRB stationary 

RICE >500 HP located at a major 

source of HAP emissions

complying with the requirement 

to reduce formaldehyde 

emissions by 76 percent or more 

(or by 75 percent or more, if 

applicable) and not using NSCR; 

or 

existing, new and reconstructed 

4SRB stationary RICE >500 HP 

located at a major source of 

HAP emissions complying with 

the requirement to limit the 

concentration of formaldehyde 

in the stationary RICE exhaust 

to 350 ppbvd or less at 15 

percent O2 and not using NSCR.

Comply with any operating 

limitations approved by the 

Administrator.

1Sources can petition the Administrator pursuant to the 

requirements of 40 CFR 63.8(f) for a different temperature 

range.

23. Table 2b to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 2b to Subpart ZZZZ of Part 63. Operating Limitations for 

New and Reconstructed 2SLB and CI Stationary RICE >500 HP 

Located at a Major Source of HAP Emissions, New and 

Reconstructed 4SLB Stationary RICE ≥250 HP Located at a Major 

Source of HAP Emissions, Existing CI Stationary RICE >500 HP, 

and Existing 4SLB Stationary RICE >500 HP Located at an Area 

Source of HAP Emissions 

As stated in §§63.6600, 63.6601, 63.6603, 63.6630, and 63.6640, 

you must comply with the following operating limitations for new 

and reconstructed 2SLB and CI stationary RICE >500 HP located at 

a major source of HAP emissions; new and reconstructed 4SLB 

stationary RICE ≥250 HP located at a major source of HAP 

emissions; and existing CI stationary RICE >500 HP:
Page 140 of 200

For each... You must meet the following 

operating limitation, except 

during periods of startup...

1. New and reconstructed 2SLB 

and CI stationary RICE >500 HP 

located at a major source of 

HAP emissions and new and 

reconstructed 4SLB stationary 

RICE ≥250 HP located at a major 

source of HAP emissions

complying with the requirement 

to reduce CO emissions and 

using an oxidation catalyst; 

and

New and reconstructed 2SLB and 

CI stationary RICE >500 HP

located at a major source of 

HAP emissions and new and 

reconstructed 4SLB stationary 

RICE ≥250 HP located at a major 

source of HAP emissions

complying with the requirement 

to limit the concentration of 

formaldehyde in the stationary 

RICE exhaust and using an 

oxidation catalyst

a. maintain your catalyst so 

that the pressure drop across 

the catalyst does not change by 

more than 2 inches of water at 

100 percent load plus or minus 

10 percent from the pressure 

drop across the catalyst that 

was measured during the initial 

performance test; and

b. maintain the temperature of 

your stationary RICE exhaust so 

that the catalyst inlet 

temperature is greater than or 

equal to 450°F and less than or 

equal to 1350°F.1

2. Existing CI stationary RICE 

>500 HP complying with the 

requirement to limit or reduce

the concentration of CO in the 

stationary RICE exhaust and 

using an oxidation catalyst 

a. maintain your catalyst so 

that the pressure drop across 

the catalyst does not change by 

more than 2 inches of water 

from the pressure drop across 

the catalyst that was measured 

during the initial performance 

test; and

b. maintain the temperature of 

your stationary RICE exhaust so 

that the catalyst inlet 

temperature is greater than or 

equal to 450°F and less than or 

equal to 1350°F.1
Page 141 of 200

3. New and reconstructed 2SLB 

and CI stationary RICE >500 HP 

located at a major source of 

HAP emissions and new and 

reconstructed 4SLB stationary 

RICE ≥250 HP located at a major 

source of HAP emissions

complying with the requirement 

to reduce CO emissions and not 

using an oxidation catalyst; 

and

New and reconstructed 2SLB and 

CI stationary RICE >500 HP 

located at a major source of 

HAP emissions and new and 

reconstructed 4SLB stationary 

RICE ≥250 HP located at a major 

source of HAP emissions

complying with the requirement 

to limit the concentration of 

formaldehyde in the stationary 

RICE exhaust and not using an 

oxidation catalyst

and

existing CI stationary RICE 

>500 HP complying with the 

requirement to limit or reduce

the concentration of CO in the 

stationary RICE exhaust and not 

using an oxidation catalyst

Comply with any operating 

limitations approved by the 

Administrator.

1Sources can petition the Administrator pursuant to the 

requirements of 40 CFR 63.8(f) for a different temperature 

range.

24. Table 2c to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 2c to Subpart ZZZZ of Part 63. Requirements for Existing 

Compression Ignition Stationary RICE Located at a Major Source 

of HAP Emissions and Existing Spark Ignition Stationary RICE 

≤500 HP Located at a Major Source of HAP Emissions
Page 142 of 200

As stated in §§63.6600, 63.6602, and 63.6640, you must comply 

with the following requirements for existing compression 

ignition stationary RICE located at a major source of HAP 

emissions and existing spark ignition stationary RICE ≤500 HP 

located at a major source of HAP emissions:

For each... You must meet the 

following requirement, 

except during periods of 

startup...

During periods of 

startup you must...

1. Emergency 

stationary CI 

RICE and black 

start stationary 

CI RICE.1 

a. Change oil and filter 

every 500 hours of 

operation or annually, 

whichever comes first;2

b. Inspect air cleaner 

every 1,000 hours of 

operation or annually, 

whichever comes first, 

and replace as necessary; 

c. Inspect all hoses and 

belts every 500 hours of 

operation or annually, 

whichever comes first, 

and replace as 

necessary.3

Minimize the 

engine’s time spent 

at idle and minimize 

the engine’s startup 

time at startup to a 

period needed for 

appropriate and safe 

loading of the 

engine, not to 

exceed 30 minutes, 

after which time the 

non-startup emission 

limitations apply.3

2. NonEmergency, nonblack start 

stationary CI 

RICE <100 HP. 

a. Change oil and filter 

every 1,000 hours of 

operation or annually, 

whichever comes first2;

b. Inspect air cleaner 

every 1,000 hours of 

operation or annually, 

whichever comes first, 

and replace as necessary; 

c. Inspect all hoses and 

belts every 500 hours of 

operation or annually, 

whichever comes first, 

and replace as 

necessary.3

3. NonEmergency, nonblack start CI 

stationary RICE 

100<HP<300 HP.

Limit concentration of CO 

in the stationary RICE 

exhaust to 230 ppmvd or 

less at 15 percent O2.
Page 143 of 200

4. NonEmergency, nonblack start CI 

stationary RICE 

300<HP<500.

a. Limit concentration of 

CO in the stationary RICE 

exhaust to 49 ppmvd or 

less at 15 percent O2; or

b. Reduce CO emissions by 

70 percent or more. 

5. NonEmergency, nonblack start 

stationary CI 

RICE >500 HP.

a. Limit concentration of 

CO in the stationary RICE 

exhaust to 23 ppmvd or 

less at 15 percent O2; or

b. Reduce CO emissions by 

70 percent or more.

6. Emergency 

stationary SI 

RICE and black 

start stationary 

SI RICE.1

a. Change oil and filter 

every 500 hours of 

operation or annually, 

whichever comes first;2

b. Inspect spark plugs 

every 1,000 hours of 

operation or annually, 

whichever comes first, 

and replace as necessary; 

c. Inspect all hoses and 

belts every 500 hours of 

operation or annually, 

whichever comes first, 

and replace as 

necessary.3

7. NonEmergency, nonblack start 

stationary SI 

RICE <100 HP

that are not 

2SLB stationary 

RICE. 

a. Change oil and filter 

every 1,440 hours of 

operation or annually, 

whichever comes first2;

b. Inspect spark plugs 

every 1,440 hours of 

operation or annually, 

whichever comes first, 

and replace as necessary; 

c. Inspect all hoses and 

belts every 1,440 hours 

of operation or annually, 

whichever comes first, 

and replace as 

necessary.3
Page 144 of 200

8. NonEmergency, nonblack start 2SLB 

stationary SI 

RICE <100 HP.

a. Change oil and filter 

every 4,320 hours of 

operation or annually, 

whichever comes first2;

b. Inspect spark plugs 

every 4,320 hours of 

operation or annually, 

whichever comes first, 

and replace as necessary; 

c. Inspect all hoses and 

belts every 4,320 hours 

of operation or annually, 

whichever comes first, 

and replace as 

necessary.3

9. Nonemergency, nonblack start 2SLB 

stationary RICE 

100≤HP≤500

Limit concentration of CO 

in the stationary RICE 

exhaust to 225 ppmvd or 

less at 15 percent O2

10. Nonemergency, nonblack start 4SLB 

stationary RICE 

100≤HP≤500

Limit concentration of CO 

in the stationary RICE 

exhaust to 47 ppmvd or 

less at 15 percent O2

11. Nonemergency, nonblack start 4SRB 

stationary RICE 

100≤HP≤500

Limit concentration of 

formaldehyde in the 

stationary RICE exhaust 

to 10.3 ppmvd or less at 

15 percent O2

12. Nonemergency, nonblack start 

stationary RICE 

100≤HP≤500 which 

combusts 

landfill or 

digester gas 

equivalent to 10 

percent or more 

of the gross 

heat input on an 

annual basis

Limit concentration of CO 

in the stationary RICE 

exhaust to 177 ppmvd or 

less at 15 percent O2

1 If an emergency engine is operating during an emergency and it 

is not possible to shut down the engine in order to perform the 

work practice requirements on the schedule required in Table 2c 

of this subpart, or if performing the work practice on the 
Page 145 of 200

required schedule would otherwise pose an unacceptable risk 

under federal, state, or local law, the work practice can be 

delayed until the emergency is over or the unacceptable risk 

under federal, state, or local law has abated. The work practice 

should be performed as soon as practicable after the emergency 

has ended or the unacceptable risk under federal, state, or 

local law has abated. Sources must report any failure to perform 

the work practice on the schedule required and the federal, 

state or local law under which the risk was deemed unacceptable.

2Sources have the option to utilize an oil analysis program as 

described in §63.6625(i) in order to extend the specified oil 

change requirement in Table 2c of this subpart. 

3 Sources can petition the Administrator pursuant to the 

requirements of 40 CFR 63.6(g) for alternative work practices.

25. Table 2d to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 2d to Subpart ZZZZ of Part 63. Requirements for Existing 

Stationary RICE Located at Area Sources of HAP Emissions 

As stated in §§63.6603 and 63.6640, you must comply with the 

following requirements for existing stationary RICE located at 

area sources of HAP emissions:

For each... You must meet the 

following 

requirement, except 

during periods of 

startup...

During periods of 

startup you must...

1. Non-Emergency, 

non-black start CI 

stationary RICE 

<300 HP

a. Change oil and 

filter every 1,000 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect air 

cleaner every 1,000 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; 

c. Inspect all 

hoses and belts 

every 500 hours of 

Minimize the engine’s 

time spent at idle and 

minimize the engine’s 

startup time at startup 

to a period needed for 

appropriate and safe 

loading of the engine, 

not to exceed 30 

minutes, after which 

time the non-startup 

emission limitations 

apply.
Page 146 of 200

operation or 

annually, whichever 

comes first, and 

replace as 

necessary.

2. Non-Emergency, 

non-black start CI 

stationary RICE 

300<HP<500

a. Limit 

concentration of CO 

in the stationary 

RICE exhaust to 49 

ppmvd at 15 percent 

O2;

or 

b. Reduce CO 

emissions by 70 

percent or more.

3. Non-Emergency, 

non-black start CI 

stationary RICE 

>500 HP

a. Limit 

concentration of CO 

in the stationary 

RICE exhaust to 23 

ppmvd at 15 percent 

O2;

or 

b. Reduce CO 

emissions by 70 

percent or more.

4. Emergency 

stationary CI RICE 

and black start 

stationary CI 

RICE2

a. Change oil and 

filter every 500 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect air 

cleaner every 1,000 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; and

c. Inspect all 

hoses and belts 

every 500 hours of 

operation or 

annually, whichever 

comes first, and 

replace as 

necessary.
Page 147 of 200

5. Emergency 

stationary SI 

RICE; black start 

stationary SI 

RICE; nonemergency, nonblack start 4SLB 

stationary RICE 

>500 HP that 

operate 24 hours 

or less per 

calendar year; 

non-emergency, 

non-black start 

4SRB stationary 

RICE >500 HP that 

operate 24 hours 

or less per 

calendar year2

a. Change oil and 

filter every 500 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect spark 

plugs every 1,000 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; and

c. Inspect all 

hoses and belts 

every 500 hours of 

operation or 

annually, whichever 

comes first, and 

replace as 

necessary.

6. Non-emergency, 

non-black start 

2SLB stationary 

RICE

a. Change oil and 

filter every 4,320 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect spark 

plugs every 4,320 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; and

c. Inspect all 

hoses and belts 

every 4,320 hours 

of operation or 

annually, whichever 

comes first, and

replace as 

necessary.
Page 148 of 200

7. Non-emergency, 

non-black start 

4SLB stationary 

RICE ≤500 HP; nonemergency, nonblack start 4SLB 

remote stationary 

RICE >500 HP

a. Change oil and 

filter every 1,440 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect spark 

plugs every 1,440 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; and

c. Inspect all 

hoses and belts 

every 1,440 hours 

of operation or 

annually, whichever 

comes first, and 

replace as 

necessary.

8. Non-emergency, 

non-black start 

4SLB stationary 

RICE >500 HP that 

are not remote 

stationary RICE 

and that operate 

more than 24 hours 

per calendar year

Install an 

oxidation catalyst 

to reduce HAP 

emissions from the 

stationary RICE
Page 149 of 200

9. Non-emergency, 

non-black start 

4SRB stationary 

RICE ≤500 HP; nonemergency, nonblack start 4SRB 

remote stationary 

RICE >500 HP

a. Change oil and 

filter every 1,440 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect spark 

plugs every 1,440 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; and

c. Inspect all 

hoses and belts 

every 1,440 hours 

of operation or 

annually, whichever 

comes first, and 

replace as 

necessary.

10. Non-emergency, 

non-black start 

4SRB stationary 

RICE >500 HP that 

are not remote 

stationary RICE 

and that operate 

more than 24 hours 

per calendar year

Install NSCR to 

reduce HAP 

emissions from the 

stationary RICE 
Page 150 of 200

11. Non-emergency, 

non-black start 

stationary RICE 

which combusts 

landfill or 

digester gas 

equivalent to 10 

percent or more of 

the gross heat 

input on an annual 

basis

a. Change oil and 

filter every 1,440 

hours of operation 

or annually, 

whichever comes 

first;1

b. Inspect spark 

plugs every 1,440 

hours of operation 

or annually, 

whichever comes 

first, and replace 

as necessary; and

c. Inspect all 

hoses and belts 

every 1,440 hours 

of operation or 

annually, whichever 

comes first, and 

replace as 

necessary.

1 Sources have the option to utilize an oil analysis program as 

described in §63.6625(i) in order to extend the specified oil 

change requirement in Table 2d of this subpart.

2 If an emergency engine is operating during an emergency and it 

is not possible to shut down the engine in order to perform the 

management practice requirements on the schedule required in 

Table 2d of this subpart, or if performing the management 

practice on the required schedule would otherwise pose an 

unacceptable risk under federal, state, or local law, the 

management practice can be delayed until the emergency is over 

or the unacceptable risk under federal, state, or local law has 

abated. The management practice should be performed as soon as 

practicable after the emergency has ended or the unacceptable 

risk under federal, state, or local law has abated. Sources must 

report any failure to perform the management practice on the 

schedule required and the federal, state or local law under 

which the risk was deemed unacceptable.

26. Table 3 to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 3 to Subpart ZZZZ of Part 63. Subsequent Performance Tests 

As stated in §§63.6615 and 63.6620, you must comply with the 

following subsequent performance test requirements:
Page 151 of 200

For each... Complying with the 

requirement to...

You must...

1. New or 

reconstructed 2SLB 

stationary RICE 

>500 HP located at 

major sources; new 

or reconstructed 

4SLB stationary 

RICE ≥250 HP 

located at major 

sources; and new 

or reconstructed 

CI stationary RICE 

>500 HP located at 

major sources. 

Reduce CO 

emissions and not 

using a CEMS

Conduct subsequent 

performance tests 

semiannually1.

2. 4SRB stationary 

RICE ≥5,000 HP 

located at major 

sources.

Reduce 

formaldehyde 

emissions

Conduct subsequent 

performance tests 

semiannually1.

3. Stationary RICE 

>500 HP located at 

major sources and 

new or 

reconstructed 4SLB 

stationary RICE 

250≤HP≤500 located 

at major sources. 

Limit the 

concentration of 

formaldehyde in 

the stationary 

RICE exhaust

Conduct subsequent 

performance tests 

semiannually1.

4. Existing nonemergency, nonblack start CI 

stationary RICE 

>500 HP that are 

not limited use 

stationary RICE 

Limit or reduce CO 

emissions and not 

using a CEMS

Conduct subsequent 

performance tests 

every 8,760 hrs or 

3 years, whichever 

comes first.

5. Existing nonemergency, nonblack start CI 

stationary RICE 

>500 HP that are 

limited use 

stationary RICE

Limit or reduce CO 

emissions and not 

using a CEMS

Conduct subsequent 

performance tests 

every 8,760 hrs or 

5 years, whichever 

comes first.

1 After you have demonstrated compliance for two consecutive 

tests, you may reduce the frequency of subsequent performance 

tests to annually. If the results of any subsequent annual 

performance test indicate the stationary RICE is not in 
Page 152 of 200

compliance with the CO or formaldehyde emission limitation, or 

you deviate from any of your operating limitations, you must 

resume semiannual performance tests.

27. Table 4 to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 4 to Subpart ZZZZ of Part 63. Requirements for Performance 

Tests

As stated in §§63.6610, 63.6611, 63.6612, 63.6620, and 63.6640, 

you must comply with the following requirements for performance 

tests for stationary RICE:

For 

each...

Complying 

with the 

requirement 

to...

You 

must...

Using... According to 

the 

following 

requirements

...

1. 2SLB, 

4SLB, and 

CI 

stationary 

RICE

a. reduce 

CO 

emissions

i. 

Measure 

the O2 at 

the inlet 

and 

outlet of 

the 

control 

device; 

and

(1) 

Method 3 

or 3A or 

3B of 40 

CFR part 

60, 

appendix 

A, or 

ASTM 

Method

D6522-00 

(2005)a

(incorpo

rated by 

referenc

e, see 

§63.14).

(a) 

Measurements 

to determine 

O2 must be 

made at the 

same time as 

the 

measurements 

for CO 

concentration.

ii. 

Measure 

the CO at 

the inlet 

and the 

outlet of 

the 

control 

device

(1) ASTM 

D6522-00

(2005)a,b

(incorpo

ra-ted 

by 

referenc

e, see 

§63.14) 

(a) The CO 

concentration must be 

at 15 

percent O2, 

dry basis.
Page 153 of 200

or 

Method 

10 of 40 

CFR part 

60, 

appendix 

A.

2. 4SRB 

stationary 

RICE

a. reduce 

formaldehyd

e emissions

i. Select 

the 

sampling 

port 

location 

and the 

number of 

traverse 

points; 

and

(1) 

Method 1 

or 1A of 

40 CFR 

part 60, 

appendix 

A 

§63.7(d)

(1)(i)

(a) sampling 

sites must 

be located 

at the inlet 

and outlet 

of the 

control 

device.

ii. 

Measure 

O2 at the 

inlet and 

outlet of 

the 

control 

device; 

and

(1) 

Method 3 

or 3A or 

3B of 40 

CFR part 

60, 

appendix 

A, or 

ASTM 

Method 

D6522-

00(2005)

.

(a) 

measurements 

to determine 

O2 

concentratio

n must be 

made at the 

same time as 

the 

measurements 

for 

formaldehyde

or THC

concentratio

n.
Page 154 of 200

iii. 

Measure 

moisture 

content 

at the 

inlet and 

outlet of 

the 

control 

device; 

and

(1) 

Method 4 

of 40 

CFR part 

60, 

appendix 

A, or 

Test 

Method 

320 of 

40 CFR 

part 63, 

appendix 

A, or 

ASTM D 

6348-03

(a) 

measurements 

to determine 

moisture 

content must 

be made at 

the same 

time and 

location as 

the 

measurements 

for 

formaldehyde

or THC

concentratio

n.

iv. If 

demonstra

ting 

complianc

e with 

the 

formaldeh

yde 

percent 

reduction 

requireme

nt, 

measure 

formaldehyde at 

the inlet 

and the 

outlet of 

the 

control 

device

(1) 

Method 

320 or 

323 of 

40 CFR 

part 63, 

appendix 

A; or 

ASTM 

D6348-

03c, 

provided 

in ASTM 

D6348-03 

Annex A5 

(Analyte 

Spiking 

Techniqu

e), the 

percent 

R must 

be 

greater 

than or 

equal to 

70 and 

less 

than or 

equal to 

130.

(a) 

formaldehyde 

concentration must be 

at 15 

percent O2, 

dry basis. 

Results of 

this test 

consist of 

the average 

of the three 

1-hour or 

longer runs.
Page 155 of 200

v. If 

demonstra

ting 

complianc

e with 

the THC 

percent 

reduction 

requireme

nt, 

measure 

THC at 

the inlet 

and the 

outlet of 

the 

control 

device

(1) 

Method 

25A of 

40 CFR 

part 60, 

appendix 

A

(a) THC

concentration must be 

at 15 

percent O2, 

dry basis. 

Results of 

this test 

consist of 

the average 

of the three 

1-hour or 

longer runs.

3. 

Stationary 

RICE 

a. limit 

the 

concentration of 

formaldehyde or CO

in the 

stationary 

RICE 

exhaust

i. Select 

the 

sampling 

port 

location 

and the 

number of 

traverse 

points; 

and

(1) 

Method 1 

or 1A of 

40 CFR 

part 60, 

appendix 

A 

§63.7(d)

(1)(i)

(a) if using 

a control 

device, the 

sampling 

site must be 

located at 

the outlet 

of the 

control 

device.

ii. 

Determine 

the O2

concentra

tion of 

the 

stationar

y RICE 

exhaust 

at the 

sampling 

port 

location; 

and

(1) 

Method 3 

or 3A or 

3B of 40 

CFR part 

60, 

appendix 

A, or 

ASTM 

Method 

D6522-

00(2005)

.

(a) 

measurements 

to determine 

O2 concentration must be 

made at the 

same time 

and location 

as the 

measurements 

for 

formaldehyde

or CO

concentration.

iii. 

Measure 

moisture 

(1) 

Method 4 

of 40 

(a) 

measurements 

to determine 
Page 156 of 200

content 

of the 

stationary RICE 

exhaust 

at the 

sampling 

port 

location; 

and

CFR part 

60, 

appendix 

A, or 

Test 

Method 

320 of 

40 CFR

part 63, 

appendix 

A, or 

ASTM D 

6348-03

moisture 

content must 

be made at 

the same 

time and 

location as 

the 

measurements 

for 

formaldehyde

or CO

concentratio

n.

iv. 

Measure 

formaldehyde at 

the 

exhaust 

of the 

stationary RICE;

or

(1) 

Method 

320 or 

323 of 

40 CFR 

part 63, 

appendix 

A; or 

ASTM 

D6348-

03c, 

provided 

in ASTM 

D6348-03 

Annex A5 

(Analyte 

Spiking 

Techniqu

e), the 

percent 

R must 

be 

greater 

than or 

equal to 

70 and 

less 

than or 

equal to 

130.

(a) 

Formaldehyde 

concentratio

n must be at 

15 percent 

O2, dry 

basis. 

Results of 

this test 

consist of 

the average 

of the three 

1-hour or 

longer runs.

v. 

measure 

CO at the 

exhaust 

(1) 

Method 

10 of 40 

CFR part 

(a) CO 

concentratio

n must be at 

15 percent 
Page 157 of 200

of the 

stationary RICE.

60, 

appendix 

A, ASTM 

Method 

D6522-00 

(2005)a, 

Method 

320 of 

40 CFR 

part 63, 

appendix 

A, or 

ASTM 

D6348-

03.

O2, dry 

basis. 

Results of 

this test 

consist of 

the average 

of the three 

1-hour or 

longer runs.

aYou may obtain a copy of ASTM-D6522-00 (2005) from at least one 

of the following addresses: American Society for Testing and 

Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-

2959, or University Microfilms International, 300 North Zeeb 

Road, Ann Arbor, MI 48106. ASTM-D6522-00 (2005) may be used to 

test both CI and SI stationary RICE. 

bYou may also use Method 320 of 40 CFR part 63, appendix A, or 

ASTM D6348-03.

cYou may obtain a copy of ASTM-D6348-03 from at least one of the 

following addresses: American Society for Testing and Materials, 

100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, or 

University Microfilms International, 300 North Zeeb Road, Ann 

Arbor, MI 48106.

28. Table 5 to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 5 to Subpart ZZZZ of Part 63. Initial Compliance with 

Emission Limitations and Operating Limitations

As stated in §§63.6612, 63.6625 and 63.6630, you must initially 

comply with the emission and operating limitations as required 

by the following: 

For each . . . Complying with the

requirement 

to . . .

You have 

demonstrated 

initial 

compliance if . . .
Page 158 of 200

1. New or 

reconstructed nonemergency 2SLB 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

≥250 HP located at 

a major source of 

HAP, non-emergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP located at 

an area source of 

HAP. 

a. Reduce CO 

emissions and using 

oxidation catalyst, 

and using a CPMS

i. The average 

reduction of 

emissions of CO 

determined from the 

initial performance 

test achieves the 

required CO percent 

reduction; and

ii. You have 

installed a CPMS to 

continuously 

monitor catalyst 

inlet temperature 

according to the 

requirements in 

§63.6625(b); and 

iii. You have 

recorded the 

catalyst pressure 

drop and catalyst 

inlet temperature 

during the initial 

performance test.
Page 159 of 200

2. Non-emergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP located at 

an area source of 

HAP.

a. Limit the 

concentration of 

CO, using oxidation 

catalyst, and using 

a CPMS

i. The average CO 

concentration 

determined from the 

initial performance 

test is less than 

or equal to the CO 

emission 

limitation; and

ii. You have 

installed a CPMS to 

continuously 

monitor catalyst 

inlet temperature 

according to the 

requirements in 

§63.6625(b); and 

iii. You have 

recorded the 

catalyst pressure 

drop and catalyst 

inlet temperature 

during the initial 

performance test.

3. New or 

reconstructed nonemergency 2SLB 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

≥250 HP located at 

a major source of 

HAP, non-emergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP located at 

an area source of 

HAP.

a. Reduce CO 

emissions and not 

using oxidation 

catalyst

i. The average 

reduction of 

emissions of CO 

determined from the 

initial performance 

test achieves the 

required CO percent 

reduction; and

ii. You have 

installed a CPMS to 

continuously 

monitor operating 

parameters approved 

by the 

Administrator (if 

any) according to 

the requirements in 

§63.6625(b); and 

iii. You have 

recorded the 
Page 160 of 200

approved operating 

parameters (if any) 

during the initial 

performance test.

4. Non-emergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP located at 

an area source of 

HAP.

a. Limit the 

concentration of 

CO, and not using 

oxidation catalyst

i. The average CO 

concentration 

determined from the 

initial performance 

test is less than 

or equal to the CO 

emission 

limitation; and

ii. You have 

installed a CPMS to 

continuously 

monitor operating 

parameters approved 

by the 

Administrator (if 

any) according to 

the requirements in 

§63.6625(b); and 

iii. You have 

recorded the 

approved operating 

parameters (if any) 

during the initial 

performance test.
Page 161 of 200

5. New or 

reconstructed nonemergency 2SLB 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

≥250 HP located at 

a major source of 

HAP, non-emergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP located at 

an area source of 

HAP.

a. Reduce CO 

emissions, and 

using a CEMS

i. You have 

installed a CEMS to 

continuously 

monitor CO and 

either O2 or CO2 at 

both the inlet and 

outlet of the 

oxidation catalyst 

according to the 

requirements in 

§63.6625(a); and

ii. You have 

conducted a 

performance 

evaluation of your 

CEMS using PS 3 and 

4A of 40 CFR part 

60, appendix B; and

iii. The average 

reduction of CO 

calculated using 

§63.6620 equals or 

exceeds the 

required percent 

reduction. The 

initial test 

comprises the first 

4-hour period after 

successful 

validation of the 

CEMS. Compliance 

is based on the 

average percent 

reduction achieved 

during the 4-hour 

period.
Page 162 of 200

6. Non-emergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP located at

an area source of 

HAP.

a. Limit the 

concentration of 

CO, and using a 

CEMS

i. You have 

installed a CEMS to 

continuously 

monitor CO and 

either O2 or CO2 at 

the outlet of the 

oxidation catalyst 

according to the 

requirements in 

§63.6625(a); and

ii. You have 

conducted a 

performance 

evaluation of your 

CEMS using PS 3 and 

4A of 40 CFR part 

60, appendix B; and

iii. The average 

concentration of CO 

calculated using 

§63.6620 is less 

than or equal to 

the CO emission 

limitation. The 

initial test 

comprises the first 

4-hour period after 

successful 

validation of the 

CEMS. Compliance is 

based on the 

average 

concentration 

measured during the 

4-hour period.

7. Non-emergency 

4SRB stationary 

RICE >500 HP 

located at a major 

source of HAP.

a. Reduce 

formaldehyde 

emissions and using 

NSCR

i. The average 

reduction of 

emissions of 

formaldehyde 

determined from the 

initial performance 

test is equal to or 

greater than the 

required 

formaldehyde 
Page 163 of 200

percent reduction, 

or the average 

reduction of 

emissions of THC 

determined from the 

initial performance 

test is equal to or 

greater than 30 

percent; and

ii. You have 

installed a CPMS to 

continuously 

monitor catalyst 

inlet temperature 

according to the 

requirements in 

§63.6625(b); and

iii. You have 

recorded the 

catalyst pressure 

drop and catalyst

inlet temperature 

during the initial 

performance test.

8. Non-emergency 

4SRB stationary 

RICE >500 HP 

located at a major 

source of HAP.

a. Reduce 

formaldehyde 

emissions and not 

using NSCR

i. The average 

reduction of 

emissions of 

formaldehyde 

determined from the 

initial performance 

test is equal to or 

greater than the 

required 

formaldehyde 

percent reduction; 

and

ii. You have 

installed a CPMS to 

continuously 

monitor operating 

parameters approved 

by the 

Administrator (if 

any) according to 
Page 164 of 200

the requirements in 

§63.6625(b); and 

iii. You have 

recorded the 

approved operating 

parameters (if any) 

during the initial 

performance test.

9. New or 

reconstructed nonemergency 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

250≤HP≤500 located 

at a major source 

of HAP, and 

existing nonemergency 4SRB 

stationary RICE 

>500 HP located at 

a major source of 

HAP.

a. Limit the 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust and using 

oxidation catalyst 

or NSCR

i. The average 

formaldehyde 

concentration, 

corrected to 15 

percent O2, dry 

basis, from the 

three test runs is 

less than or equal 

to the formaldehyde 

emission 

limitation; and

ii. You have 

installed a CPMS to 

continuously 

monitor catalyst 

inlet temperature 

according to the 

requirements in 

§63.6625(b); and 

iii. You have 

recorded the 

catalyst pressure 

drop and catalyst 

inlet temperature 

during the initial 

performance test.

10. New or 

reconstructed nonemergency 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

a. Limit the 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust and not 

using oxidation 

catalyst or NSCR

i. The average 

formaldehyde 

concentration, 

corrected to 15 

percent O2, dry 

basis, from the 

three test runs is 

less than or equal 

to the formaldehyde 

emission 
Page 165 of 200

250≤HP≤500 located 

at a major source 

of HAP, and 

existing nonemergency 4SRB 

stationary RICE 

>500 HP located at 

a major source of 

HAP.

limitation; and

ii. You have 

installed a CPMS to 

continuously 

monitor operating 

parameters approved 

by the 

Administrator (if 

any) according to 

the requirements in 

§63.6625(b); and 

iii. You have 

recorded the 

approved operating 

parameters (if any) 

during the initial 

performance test.

11. Existing nonemergency 

stationary RICE 

100≤HP≤500 located 

at a major source 

of HAP, and 

existing nonemergency 

stationary CI RICE 

300<HP≤500 located 

at an area source 

of HAP. 

a. Reduce CO 

emissions.

i. The average 

reduction of 

emissions of CO or 

formaldehyde, as 

applicable 

determined from the 

initial performance 

test is equal to or 

greater than the 

required CO or 

formaldehyde, as 

applicable, percent 

reduction.

12. Existing nonemergency 

stationary RICE 

100≤HP≤500 located 

at a major source 

of HAP, and 

existing nonemergency 

stationary CI RICE 

300<HP≤500 located 

at an area source 

of HAP. 

a. Limit the 

concentration of 

formaldehyde or CO

in the stationary 

RICE exhaust.

i. The average 

formaldehyde or CO 

concentration, as 

applicable, 

corrected to 15 

percent O2, dry 

basis, from the 

three test runs is 

less than or equal 

to the formaldehyde 

or CO emission 

limitation, as 

applicable.

13. Existing nonemergency 4SLB a. Install an 

oxidation catalyst

i. You have 

conducted an 
Page 166 of 200

stationary RICE 

>500 HP located at 

an area source of 

HAP that are not 

remote stationary 

RICE and that are 

operated more than 

24 hours per 

calendar year

initial compliance 

demonstration as 

specified in 

§63.6630(e) to show 

that the average 

reduction of 

emissions of CO is 

93 percent or more, 

or the average CO 

concentration is 

less than or equal 

to 47 ppmvd at 15 

percent O2

ii. You have 

installed a CPMS to 

continuously 

monitor catalyst 

inlet temperature 

according to the 

requirements in 

§63.6625(b), or you 

have installed 

equipment to 

automatically shut 

down the engine if 

the catalyst inlet 

temperature exceeds 

1350°F.

14. Existing nonemergency 4SRB 

stationary RICE 

>500 HP located at 

an area source of 

HAP that are not 

remote stationary 

RICE and that are 

operated more than 

24 hours per 

calendar year

a. Install NSCR i. You have 

conducted an 

initial compliance 

demonstration as 

specified in 

§63.6630(e) to show 

that the average 

reduction of 

emissions of CO is 

75 percent or more, 

or the average 

reduction of 

emissions of THC is 

30 percent or more 

ii. You have 

installed a CPMS to 

continuously 

monitor catalyst 
Page 167 of 200

inlet temperature 

according to the 

requirements in 

§63.6625(b), or you 

have installed 

equipment to 

automatically shut 

down the engine if 

the catalyst inlet 

temperature exceeds 

1250°F.

29. Table 6 to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 6 to Subpart ZZZZ of Part 63. Continuous Compliance with 

Emission Limitations, Operating Limitations, Work Practices, and 

Management Practices

As stated in §63.6640, you must continuously comply with the 

emissions and operating limitations and work or management 

practices as required by the following:

For each . . . Complying with the 

requirement to . . 

.

You must 

demonstrate 

continuous 

compliance by 

. . .

1. New or 

reconstructed nonemergency 2SLB 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

≥250 HP located at 

a major source of 

HAP, and new or 

reconstructed nonemergency CI 

a. Reduce CO 

emissions and using 

an oxidation 

catalyst, and using 

a CPMS

i. Conducting 

semiannual 

performance tests 

for CO to 

demonstrate that 

the required CO 

percent reduction 

is achieveda; and

ii. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b); and
Page 168 of 200

stationary RICE 

>500 HP located at 

a major source of 

HAP.

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 

4-hour rolling 

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; and 

v. Measuring the 

pressure drop 

across the catalyst 

once per month and 

demonstrating that 

the pressure drop 

across the catalyst 

is within the 

operating 

limitation 

established during 

the performance 

test.

2. New or 

reconstructed nonemergency 2SLB 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

≥250 HP located at 

a major source of 

HAP, and new or 

reconstructed nonemergency CI 

stationary RICE 

>500 HP located at 

a major source of 

HAP.

a. Reduce CO 

emissions and not 

using an oxidation 

catalyst, and using 

a CPMS

i. Conducting 

semiannual 

performance tests 

for CO to 

demonstrate that 

the required CO 

percent reduction 

is achieveda; and

ii. Collecting the 

approved operating 

parameter (if any) 

data according to 

§63.6625(b); and

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 
Page 169 of 200

4-hour rolling 

averages within the 

operating 

limitations for the 

operating 

parameters 

established during 

the performance 

test.

3. New or 

reconstructed nonemergency 2SLB 

stationary RICE 

>500 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 4SLB 

stationary RICE 

≥250 HP located at 

a major source of 

HAP, new or 

reconstructed nonemergency 

stationary CI RICE 

>500 HP located at 

a major source of 

HAP, and existing 

non-emergency 

stationary CI RICE 

>500 HP.

a. Reduce CO 

emissions or limit 

the concentration 

of CO in the 

stationary RICE 

exhaust, and using 

a CEMS

i. Collecting the 

monitoring data 

according to 

§63.6625(a), 

reducing the 

measurements to 1-

hour averages, 

calculating the 

percent reduction 

or concentration of 

CO emissions 

according to 

§63.6620; and 

ii. Demonstrating 

that the catalyst 

achieves the 

required percent 

reduction of CO 

emissions over the 

4-hour averaging 

period, or that the 

emission remain at 

or below the CO 

concentration 

limit; and

iii. Conducting an 

annual RATA of your 

CEMS using PS 3 and 

4A of 40 CFR part 

60, appendix B, as 

well as daily and 

periodic data 

quality checks in 

accordance with 40 

CFR part 60, 

appendix F, 
Page 170 of 200

procedure 1.

4. Non-emergency 

4SRB stationary 

RICE >500 HP 

located at a major 

source of HAP.

a. Reduce 

formaldehyde 

emissions and using 

NSCR

i. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b); and

ii. reducing these 

data to 4-hour 

rolling averages; 

and

iii. Maintaining 

the 4-hour rolling 

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; and 

iv. Measuring the 

pressure drop 

across the catalyst 

once per month and 

demonstrating that 

the pressure drop 

across the catalyst 

is within the 

operating 

limitation 

established during 

the performance 

test.

5. Non-emergency 

4SRB stationary 

RICE >500 HP 

located at a major 

source of HAP.

a. Reduce 

formaldehyde 

emissions and not 

using NSCR

i. Collecting the 

approved operating 

parameter (if any) 

data according to 

§63.6625(b); and

ii. Reducing these 

data to 4-hour 

rolling averages; 

and

iii. Maintaining 

the 4-hour rolling 

averages within the 
Page 171 of 200

operating 

limitations for the 

operating 

parameters 

established during 

the performance 

test.

6. Non-emergency 

4SRB stationary 

RICE with a brake 

HP ≥5,000 located 

at a major source 

of HAP.

a. Reduce 

formaldehyde 

emissions

Conducting 

semiannual 

performance tests 

for formaldehyde to 

demonstrate that 

the required 

formaldehyde 

percent reduction 

is achieved, or to 

demonstrate that 

the average 

reduction of 

emissions of THC 

determined from the 

performance test is 

equal to or greater 

than 30 percent.a

7. New or 

reconstructed nonemergency 

stationary RICE 

>500 HP located at 

a major source of 

HAP and new or 

reconstructed nonemergency 4SLB 

stationary RICE 

250≤HP≤500 located 

at a major source 

of HAP.

a. Limit the 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust and using 

oxidation catalyst 

or NSCR

i. Conducting 

semiannual 

performance tests 

for formaldehyde to 

demonstrate that 

your emissions 

remain at or below 

the formaldehyde 

concentration 

limita; and

ii. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b); and

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 
Page 172 of 200

4-hour rolling 

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; and 

v. Measuring the 

pressure drop 

across the catalyst 

once per month and 

demonstrating that 

the pressure drop 

across the catalyst 

is within the 

operating 

limitation 

established during 

the performance 

test.

8. New or 

reconstructed nonemergency 

stationary RICE 

>500 HP located at 

a major source of 

HAP and new or 

reconstructed nonemergency 4SLB 

stationary RICE 

250≤HP≤500 located 

at a major source 

of HAP.

a. Limit the 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust and not 

using oxidation 

catalyst or NSCR

i. Conducting 

semiannual 

performance tests 

for formaldehyde to 

demonstrate that 

your emissions 

remain at or below 

the formaldehyde 

concentration 

limita; and

ii. Collecting the 

approved operating 

parameter (if any) 

data according to 

§63.6625(b); and

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 

4-hour rolling 

averages within the 

operating 

limitations for the 
Page 173 of 200

operating

parameters 

established during 

the performance 

test.

9. Existing 

emergency and 

black start 

stationary RICE 

≤500 HP located at 

a major source of 

HAP, existing nonemergency 

stationary RICE 

<100 HP located at 

a major source of 

HAP, existing 

emergency and 

black start 

stationary RICE 

located at an area 

source of HAP, 

existing nonemergency 

stationary CI RICE 

≤300 HP located at 

an area source of 

HAP, existing nonemergency 2SLB 

stationary RICE 

located at an area 

source of HAP, 

existing nonemergency 

stationary SI RICE 

located at an area 

source of HAP 

which combusts 

landfill or 

digester gas 

equivalent to 10 

percent or more of 

the gross heat 

input on an annual 

basis, existing 

non-emergency 4SLB 

and 4SRB 

a. Work or 

Management 

practices.

i. Operating and 

maintaining the 

stationary RICE 

according to the 

manufacturer’s 

emission-related 

operation and 

maintenance 

instructions;

or

ii. Develop and 

follow your own 

maintenance plan 

which must provide 

to the extent 

practicable for the 

maintenance and 

operation of the 

engine in a manner 

consistent with 

good air pollution 

control practice 

for minimizing 

emissions.
Page 174 of 200

stationary RICE 

≤500 HP located at 

an area source of 

HAP, existing nonemergency 4SLB and 

4SRB stationary 

RICE >500 HP 

located at an area 

source of HAP that 

operate 24 hours 

or less per 

calendar year, and 

existing nonemergency 4SLB and 

4SRB stationary 

RICE >500 HP 

located at an area 

source of HAP that 

are remote 

stationary RICE.

10. Existing 

stationary CI RICE 

>500 HP that are 

not limited use 

stationary RICE.

a. Reduce CO 

emissions, or limit 

the concentration 

of CO in the 

stationary RICE 

exhaust, and using 

oxidation catalyst

i. Conducting 

performance tests 

every 8,760 hours 

or 3 years, 

whichever comes 

first, for CO or 

formaldehyde, as 

appropriate, to 

demonstrate that 

the required CO or 

formaldehyde, as 

appropriate, 

percent reduction 

is achieved or that 

your emissions 

remain at or below 

the CO or 

formaldehyde 

concentration 

limit; and

ii. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b); and
Page 175 of 200

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 

4-hour rolling 

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; and 

v. Measuring the 

pressure drop 

across the catalyst 

once per month and 

demonstrating that 

the pressure drop 

across the catalyst 

is within the 

operating 

limitation 

established during 

the performance 

test.

11. Existing 

stationary CI RICE 

>500 HP that are 

not limited use 

stationary RICE.

a. Reduce CO 

emissions, or limit 

the concentration 

of CO in the 

stationary RICE 

exhaust, and not 

using oxidation 

catalyst

i. Conducting 

performance tests 

every 8,760 hours 

or 3 years, 

whichever comes 

first, for CO or 

formaldehyde, as 

appropriate, to 

demonstrate that 

the required CO or 

formaldehyde, as 

appropriate, 

percent reduction 

is achieved or that 

your emissions 

remain at or below 

the CO or 

formaldehyde 

concentration 

limit; and
Page 176 of 200

ii. Collecting the 

approved operating 

parameter (if any) 

data according to 

§63.6625(b); and

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 

4-hour rolling 

averages within the 

operating 

limitations for the 

operating 

parameters 

established during 

the performance 

test.

12. Existing 

limited use CI 

stationary RICE 

>500 HP.

a. Reduce CO 

emissions or limit 

the concentration 

of CO in the 

stationary RICE 

exhaust, and using 

an oxidation 

catalyst

i. Conducting 

performance tests 

every 8,760 hours 

or 5 years, 

whichever comes 

first, for CO or 

formaldehyde, as 

appropriate, to 

demonstrate that 

the required CO or 

formaldehyde, as 

appropriate, 

percent reduction 

is achieved or

that your emissions 

remain at or below 

the CO or 

formaldehyde 

concentration 

limit; and 

ii. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b); and
Page 177 of 200

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 

4-hour rolling 

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; and 

v. Measuring the 

pressure drop 

across the catalyst 

once per month and 

demonstrating that 

the pressure drop 

across the catalyst 

is within the 

operating 

limitation 

established during 

the performance 

test.

13. Existing 

limited use CI 

stationary RICE 

>500 HP.

a. Reduce CO 

emissions or limit 

the concentration 

of CO in the 

stationary RICE 

exhaust, and not 

using an oxidation 

catalyst

i. Conducting 

performance tests 

every 8,760 hours 

or 5 years, 

whichever comes 

first, for CO or 

formaldehyde, as 

appropriate, to 

demonstrate that 

the required CO or 

formaldehyde, as 

appropriate, 

percent reduction 

is achieved or

that your emissions 

remain at or below 

the CO or 

formaldehyde 

concentration 

limit; and 
Page 178 of 200

ii. Collecting the 

approved operating 

parameter (if any) 

data according to 

§63.6625(b); and

iii. Reducing these 

data to 4-hour 

rolling averages; 

and

iv. Maintaining the 

4-hour rolling 

averages within the 

operating 

limitations for the 

operating 

parameters 

established during 

the performance 

test.

14. Existing nonemergency 4SLB 

stationary RICE 

>500 HP located at 

an area source of 

HAP that are not 

remote stationary 

RICE and that are 

operated more than 

24 hours per 

calendar year

a. Install an 

oxidation catalyst

i. Conducting 

annual compliance 

demonstrations as 

specified in 

§63.6640(c) to show 

that the average 

reduction of 

emissions of CO is

93 percent or more, 

or the average CO 

concentration is 

less than or equal 

to 47 ppmvd at 15 

percent O2; and 

either

ii. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b), 

reducing these data 

to 4-hour rolling 

averages; and 

maintaining the 4-

hour rolling 
Page 179 of 200

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; or

iii. Immediately 

shutting down the 

engine if the 

catalyst inlet 

temperature exceeds 

1350° F.

15. Existing nonemergency 4SRB 

stationary RICE 

>500 HP located at 

an area source of 

HAP that are not 

remote stationary 

RICE and that are 

operated more than 

24 hours per 

calendar year

a. Install NSCR i. Conducting 

annual compliance 

demonstrations as 

specified in 

§63.6640(c) to show 

that the average 

reduction of 

emissions of CO is

75 percent or more, 

or the average 

reduction of 

emissions of THC is 

30 percent or more; 

and either

ii. Collecting the 

catalyst inlet 

temperature data 

according to 

§63.6625(b), 

reducing these data 

to 4-hour rolling 

averages; and 

maintaining the 4-

hour rolling 

averages within the 

operating 

limitations for the 

catalyst inlet 

temperature; or

iii. Immediately 

shutting down the 

engine if the 

catalyst inlet 

temperature exceeds 

1250° F.
Page 180 of 200

aAfter you have demonstrated compliance for two consecutive 

tests, you may reduce the frequency of subsequent performance 

tests to annually. If the results of any subsequent annual 

performance test indicate the stationary RICE is not in 

compliance with the CO or formaldehyde emission limitation, or 

you deviate from any of your operating limitations, you must 

resume semiannual performance tests.

30. Table 7 to Subpart ZZZZ of Part 63 is revised to read 

as follows:

Table 7 to Subpart ZZZZ of Part 63. Requirements for Reports

As stated in §63.6650, you must comply with the following 

requirements for reports:

For each . . 

.

You must 

submit a . . 

.

The report must 

contain . . .

You must submit 

the report . . .

1. Existing 

nonemergency, 

non-black 

start 

stationary 

RICE 

100≤HP≤500 

located at a 

major source 

of HAP; 

existing nonemergency, 

non-black 

start 

stationary CI 

RICE >500 HP 

located at a 

major source 

of HAP; 

existing nonemergency 

4SRB 

stationary 

RICE >500 HP 

located at a 

Compliance 

report

a. If there are 

no deviations 

from any 

emission 

limitations or 

operating 

limitations that 

apply to you, a 

statement that 

there were no 

deviations from 

the emission 

limitations or 

operating 

limitations 

during the 

reporting 

period. If there 

were no periods 

during which the 

CMS, including 

CEMS and CPMS, 

was out-ofcontrol, as 

specified in 

§63.8(c)(7), a 

i. Semiannually 

according to the 

requirements in 

§63.6650(b)(1)-

(5) for engines 

that are not 

limited use 

stationary RICE 

subject to 

numerical 

emission 

limitations; and

ii. Annually 

according to the 

requirements in 

§63.6650(b)(6)-

(9) for engines 

that are limited 

use stationary 

RICE subject to 

numerical 

emission 

limitations.
Page 181 of 200

major source 

of HAP; 

existing nonemergency, 

non-black 

start 

stationary CI 

RICE >300 HP 

located at an 

area source 

of HAP; new 

or 

reconstructed 

non-emergency 

stationary 

RICE >500 HP 

located at a 

major source 

of HAP; and 

new or 

reconstructed 

non-emergency 

4SLB 

stationary 

RICE 

250≤HP≤500 

located at a 

major source 

of HAP 

statement that 

there were not 

periods during 

which the CMS 

was out-ofcontrol during 

the reporting 

period; or

b. If you had a 

deviation from 

any emission 

limitation or 

operating 

limitation 

during the 

reporting 

period, the 

information in 

§63.6650(d). If 

there were 

periods during 

which the CMS, 

including CEMS 

and CPMS, was 

out-of-control, 

as specified in 

§63.8(c)(7), the 

information in 

§63.6650(e); or

i. Semiannually 

according to the 

requirements in 

§63.6650(b).

c. If you had a 

malfunction 

during the 

reporting 

period, the 

information in 

§63.6650(c)(4).

i. Semiannually 

according to the 

requirements in 

§63.6650(b).

2. New or 

reconstructed 

non-emergency 

stationary 

RICE that 

combusts 

landfill gas 

or digester 

gas 

equivalent to 

Report a. The fuel flow 

rate of each 

fuel and the 

heating values 

that were used 

in your 

calculations, 

and you must 

demonstrate that 

the percentage 

i. Annually, 

according to the 

requirements in 

§63.6650.
Page 182 of 200

10 percent or 

more of the 

gross heat 

input on an 

annual basis

of heat input 

provided by 

landfill gas or 

digester gas, is 

equivalent to 10 

percent or more 

of the gross 

heat input on an 

annual basis; 

and

b. The operating 

limits provided 

in your 

federally 

enforceable 

permit, and any 

deviations from 

these limits; 

and

i. See item 

2.a.i.

c. Any problems 

or errors 

suspected with 

the meters.

i. See item 

2.a.i.

3. Existing 

nonemergency, 

non-black 

start 4SLB 

and 4SRB 

stationary 

RICE >500 HP 

located at an 

area source 

of HAP that 

are not 

remote 

stationary 

RICE and that 

operate more 

than 24 hours 

per calendar 

year

Compliance 

report

a. The results 

of the annual 

compliance 

demonstration, 

if conducted 

during the 

reporting 

period. 

i. Semiannually 

according to the 

requirements in 

§63.6650(b)(1)-

(5)

31. Appendix A to Subpart ZZZZ of Part 63 is added to read 

as follows:
Page 183 of 200

Appendix A

Protocol for Using an Electrochemical Analyzer to Determine

Oxygen and Carbon Monoxide Concentrations from Certain Engines 

1.0 Scope and Application. What is this Protocol?

This protocol is a procedure for using portable electrochemical 

(EC) cells for measuring carbon monoxide (CO) and oxygen (O2) 

concentrations in controlled and uncontrolled emissions from 

existing stationary 4-stroke lean burn and 4-stroke rich burn 

reciprocating internal combustion engines as specified in the 

applicable rule.

1.1 Analytes. What does this protocol determine? 

This protocol measures the engine exhaust gas concentrations of 

carbon monoxide (CO) and oxygen (O2).

Analyte CAS No. Sensitivity

Carbon monoxide (CO) 630-08-0 Minimum detectable 

limit should be 2 

percent of the 

nominal range or 1 

ppm, whichever is 

less restrictive.

Oxygen (O2) 7782-44-7

1.2 Applicability. When is this protocol acceptable?

This protocol is applicable to 40 CFR part 63, subpart ZZZZ. 

Because of inherent cross sensitivities of EC cells, you must 

not apply this protocol to other emissions sources without 

specific instruction to that effect.

1.3 Data Quality Objectives. How good must my collected data be? 
Page 184 of 200

Refer to Section 13 to verify and document acceptable analyzer 

performance.

1.4 Range. What is the targeted analytical range for this 

protocol?

The measurement system and EC cell design(s) conforming to this 

protocol will determine the analytical range for each gas 

component. The nominal ranges are defined by choosing up-scale 

calibration gas concentrations near the maximum anticipated flue 

gas concentrations for CO and O2, or no more than twice the 

permitted CO level.

1.5 Sensitivity. What minimum detectable limit will this 

protocol yield for a particular gas component?

The minimum detectable limit depends on the nominal range and 

resolution of the specific EC cell used, and the signal to noise 

ratio of the measurement system. The minimum detectable limit 

should be 2 percent of the nominal range or 1 ppm, whichever is 

less restrictive.

2.0 Summary of Protocol

In this protocol, a gas sample is extracted from an engine 

exhaust system and then conveyed to a portable EC analyzer for 

measurement of CO and O2 gas concentrations. This method provides 

measurement system performance specifications and sampling

protocols to ensure reliable data. You may use additions to, or 

modifications of vendor supplied measurement systems (e.g.,
Page 185 of 200

heated or unheated sample lines, thermocouples, flow meters, 

selective gas scrubbers, etc.) to meet the design specifications 

of this protocol. Do not make changes to the measurement system

from the as-verified configuration (Section 3.12).

3.0 Definitions

3.1 Measurement System. The total equipment required for the 

measurement of CO and O2 concentrations. The measurement system 

consists of the following major subsystems:

3.1.1 Data Recorder. A strip chart recorder, computer or digital 

recorder for logging measurement data from the analyzer output. 

You may record measurement data from the digital data display 

manually or electronically.

3.1.2 Electrochemical (EC) Cell. A device, similar to a fuel 

cell, used to sense the presence of a specific analyte and 

generate an electrical current output proportional to the 

analyte concentration.

3.1.3 Interference Gas Scrubber. A device used to remove or 

neutralize chemical compounds that may interfere with the 

selective operation of an EC cell.

3.1.4 Moisture Removal System. Any device used to reduce the 

concentration of moisture in the sample stream so as to protect 

the EC cells from the damaging effects of condensation and to

minimize errors in measurements caused by the scrubbing of 

soluble gases.
Page 186 of 200

3.1.5 Sample Interface. The portion of the system used for one 

or more of the following: sample acquisition; sample transport;

sample conditioning or protection of the EC cell from any 

degrading effects of the engine exhaust effluent; removal of 

particulate matter and condensed moisture.

3.2 Nominal Range. The range of analyte concentrations over 

which each EC cell is operated (normally 25 percent to 150

percent of up-scale calibration gas value). Several nominal 

ranges can be used for any given cell so long as the calibration 

and repeatability checks for that range remain within 

specifications.

3.3 Calibration Gas. A vendor certified concentration of a 

specific analyte in an appropriate balance gas.

3.4 Zero Calibration Error. The analyte concentration output 

exhibited by the EC cell in response to zero-level calibration 

gas.

3.5 Up-Scale Calibration Error. The mean of the difference 

between the analyte concentration exhibited by the EC cell and 

the certified concentration of the up-scale calibration gas.

3.6 Interference Check. A procedure for quantifying analytical 

interference from components in the engine exhaust gas other 

than the targeted analytes.

3.7 Repeatability Check. A protocol for demonstrating that an EC 

cell operated over a given nominal analyte concentration range 
Page 187 of 200

provides a stable and consistent response and is not 

significantly affected by repeated exposure to that gas.

3.8 Sample Flow Rate. The flow rate of the gas sample as it 

passes through the EC cell. In some situations, EC cells can 

experience drift with changes in flow rate. The flow rate must 

be monitored and documented during all phases of a sampling run.

3.9 Sampling Run. A timed three-phase event whereby an EC cell’s

response rises and plateaus in a sample conditioning phase,

remains relatively constant during a measurement data phase,

then declines during a refresh phase. The sample conditioning

phase exposes the EC cell to the gas sample for a length of time 

sufficient to reach a constant response. The measurement data 

phase is the time interval during which gas sample measurements 

can be made that meet the acceptance criteria of this protocol.

The refresh phase then purges the EC cells with CO-free air. The 

refresh phase replenishes requisite O2 and moisture in the 

electrolyte reserve and provides a mechanism to de-gas or desorb

any interference gas scrubbers or filters so as to enable a 

stable CO EC cell response. There are four primary types of 

sampling runs: pre- sampling calibrations; stack gas sampling; 

post-sampling calibration checks; and measurement system 

repeatability checks. Stack gas sampling runs can be chained

together for extended evaluations, providing all other 

procedural specifications are met.
Page 188 of 200

3.10 Sampling Day. A time not to exceed twelve hours from the 

time of the pre-sampling calibration to the post-sampling 

calibration check. During this time, stack gas sampling runs can

be repeated without repeated recalibrations, providing all other 

sampling specifications have been met.

3.11 Pre-Sampling Calibration/Post-Sampling Calibration Check.

The protocols executed at the beginning and end of each sampling 

day to bracket measurement readings with controlled performance 

checks.

3.12 Performance-Established Configuration. The EC cell and 

sampling system configuration that existed at the time that it 

initially met the performance requirements of this protocol.

4.0 Interferences.

When present in sufficient concentrations, NO and NO2 are two gas 

species that have been reported to interfere with CO 

concentration measurements. In the likelihood of this 

occurrence, it is the protocol user’s responsibility to employ 

and properly maintain an appropriate CO EC cell filter or 

scrubber for removal of these gases, as described in Section 

6.2.12.

5.0 Safety. [Reserved]

6.0 Equipment and Supplies.

6.1 What equipment do I need for the measurement system?
Page 189 of 200

The system must maintain the gas sample at conditions that will 

prevent moisture condensation in the sample transport lines, 

both before and as the sample gas contacts the EC cells. The 

essential components of the measurement system are described 

below.

6.2 Measurement System Components. 

6.2.1 Sample Probe. A single extraction-point probe constructed 

of glass, stainless steel or other non-reactive material, and of 

length sufficient to reach any designated sampling point. The 

sample probe must be designed to prevent plugging due to 

condensation or particulate matter.

6.2.2 Sample Line. Non-reactive tubing to transport the effluent 

from the sample probe to the EC cell.

6.2.3 Calibration Assembly (optional). A three-way valve 

assembly or equivalent to introduce calibration gases at ambient 

pressure at the exit end of the sample probe during calibration 

checks. The assembly must be designed such that only stack gas 

or calibration gas flows in the sample line and all gases flow 

through any gas path filters.

6.2.4 Particulate Filter (optional). Filters before the inlet of 

the EC cell to prevent accumulation of particulate material in 

the measurement system and extend the useful life of the 

components. All filters must be fabricated of materials that are 

non-reactive to the gas mixtures being sampled.
Page 190 of 200

6.2.5 Sample Pump. A leak-free pump to provide undiluted sample

gas to the system at a flow rate sufficient to minimize the 

response time of the measurement system. If located upstream of 

the EC cells, the pump must be constructed of a material that is 

non-reactive to the gas mixtures being sampled.

6.2.8 Sample Flow Rate Monitoring. An adjustable rotameter or 

equivalent device used to adjust and maintain the sample flow 

rate through the analyzer as prescribed.

6.2.9 Sample Gas Manifold (optional). A manifold to divert a 

portion of the sample gas stream to the analyzer and the 

remainder to a by-pass discharge vent. The sample gas manifold 

may also include provisions for introducing calibration gases 

directly to the analyzer. The manifold must be constructed of a 

material that is non-reactive to the gas mixtures being sampled.

6.2.10 EC cell. A device containing one or more EC cells to 

determine the CO and O2 concentrations in the sample gas stream. 

The EC cell(s) must meet the applicable performance 

specifications of Section 13 of this protocol. 

6.2.11 Data Recorder. A strip chart recorder, computer or 

digital recorder to make a record of analyzer output data. The 

data recorder resolution (i.e., readability) must be no greater 

than 1 ppm for CO; 0.1 percent for O2; and one degree (either oC

or oF) for temperature. Alternatively, you may use a digital or 
Page 191 of 200

analog meter having the same resolution to observe and manually 

record the analyzer responses.

6.2.12 Interference Gas Filter or Scrubber. A device to remove 

interfering compounds upstream of the CO EC cell. Specific 

interference gas filters or scrubbers used in the performanceestablished configuration of the analyzer must continue to be 

used. Such a filter or scrubber must have a means to determine 

when the removal agent is exhausted. Periodically replace or 

replenish it in accordance with the manufacturer’s

recommendations.

7.0 Reagents and Standards. What calibration gases are needed?

7.1 Calibration Gases. CO calibration gases for the EC cell must

be CO in nitrogen or CO in a mixture of nitrogen and O2. Use CO 

calibration gases with labeled concentration values certified by 

the manufacturer to be within ± 5 percent of the label value. 

Dry ambient air (20.9 percent O2) is acceptable for calibration 

of the O2 cell. If needed, any lower percentage O2 calibration 

gas must be a mixture of O2 in nitrogen.

7.1.1 Up-Scale CO Calibration Gas Concentration.

Choose one or more up-scale gas concentrations such that the 

average of the stack gas measurements for each stack gas 

sampling run are between 25 and 150 percent of those

concentrations. Alternatively, choose an up-scale gas that does 

not exceed twice the concentration of the applicable outlet
Page 192 of 200

standard. If a measured gas value exceeds 150 percent of the upscale CO calibration gas value at any time during the stack gas 

sampling run, the run must be discarded and repeated.

7.1.2 Up-Scale O2 Calibration Gas Concentration.

Select an O2 gas concentration such that the difference between 

the gas concentration and the average stack gas measurement or 

reading for each sample run is less than 15 percent O2. When the

average exhaust gas O2 readings are above 6 percent, you may use 

dry ambient air (20.9 percent O2) for the up-scale O2 calibration 

gas.

7.1.3 Zero Gas. Use an inert gas that contains less than 0.25 

percent of the up-scale CO calibration gas concentration. You 

may use dry air that is free from ambient CO and other 

combustion gas products (e.g., CO2).

8.0 Sample Collection and Analysis

8.1 Selection of Sampling Sites.

8.1.1 Control Device Inlet. Select a sampling site sufficiently 

downstream of the engine so that the combustion gases should be 

well mixed. Use a single sampling extraction point near the 

center of the duct (e.g., within the 10 percent centroidal 

area), unless instructed otherwise.

8.1.2 Exhaust Gas Outlet. Select a sampling site located at 

least two stack diameters downstream of any disturbance (e.g.,

turbocharger exhaust, crossover junction or recirculation take-
Page 193 of 200

off) and at least one-half stack diameter upstream of the gas 

discharge to the atmosphere. Use a single sampling extraction 

point near the center of the duct (e.g., within the 10 percent 

centroidal area), unless instructed otherwise.

8.2 Stack Gas Collection and Analysis. Prior to the first stack 

gas sampling run, conduct that the pre-sampling calibration in 

accordance with Section 10.1. Use Figure 1 to record all data. 

Zero the analyzer with zero gas. Confirm and record that the 

scrubber media color is correct and not exhausted. Then position 

the probe at the sampling point and begin the sampling run at 

the same flow rate used during the up-scale calibration. Record 

the start time. Record all EC cell output responses and the flow 

rate during the “sample conditioning phase” once per minute 

until constant readings are obtained. Then begin the 

“measurement data phase” and record readings every 15 seconds 

for at least two minutes (or eight readings), or as otherwise 

required to achieve two continuous minutes of data that meet the 

specification given in Section 13.1. Finally, perform the 

“refresh phase” by introducing dry air, free from CO and other 

combustion gases, until several minute-to-minute readings of 

consistent value have been obtained. For each run use the 

“measurement data phase” readings to calculate the average stack 

gas CO and O2 concentrations.
Page 194 of 200

8.3 EC Cell Rate. Maintain the EC cell sample flow rate so that 

it does not vary by more than ± 10 percent throughout the presampling calibration, stack gas sampling and post-sampling

calibration check. Alternatively, the EC cell sample flow rate 

can be maintained within a tolerance range that does not affect 

the gas concentration readings by more than ± 3 percent, as 

instructed by the EC cell manufacturer.

9.0 Quality Control (Reserved)

10.0 Calibration and Standardization

10.1 Pre-Sampling Calibration. Conduct the following protocol 

once for each nominal range to be used on each EC cell before 

performing a stack gas sampling run on each field sampling day. 

Repeat the calibration if you replace an EC cell before 

completing all of the sampling runs. There is no prescribed 

order for calibration of the EC cells; however, each cell must 

complete the measurement data phase during calibration. Assemble 

the measurement system by following the manufacturer's 

recommended protocols including for preparing and 

preconditioning the EC cell. Assure the measurement system has 

no leaks and verify the gas scrubbing agent is not depleted. Use 

Figure 1 to record all data.

10.1.1 Zero Calibration. For both the O2 and CO cells, introduce 

zero gas to the measurement system (e.g., at the calibration 

assembly) and record the concentration reading every minute 
Page 195 of 200

until readings are constant for at least two consecutive 

minutes. Include the time and sample flow rate. Repeat the steps 

in this section at least once to verify the zero calibration for 

each component gas.

10.1.2 Zero Calibration Tolerance. For each zero gas 

introduction, the zero level output must be less than or equal 

to ± 3 percent of the up-scale gas value or ± 1 ppm, whichever 

is less restrictive, for the CO channel and less than or equal 

to ± 0.3 percent O2 for the O2 channel.

10.1.3 Up-Scale Calibration. Individually introduce each 

calibration gas to the measurement system (e.g., at the 

calibration assembly) and record the start time. Record all EC 

cell output responses and the flow rate during this “sample 

conditioning phase” once per minute until readings are constant 

for at least two minutes. Then begin the “measurement data 

phase” and record readings every 15 seconds for a total of two 

minutes, or as otherwise required. Finally, perform the “refresh 

phase” by introducing dry air, free from CO and other combustion 

gases, until readings are constant for at least two consecutive 

minutes. Then repeat the steps in this section at least once to 

verify the calibration for each component gas. Introduce all 

gases to flow through the entire sample handling system (i.e., 

at the exit end of the sampling probe or the calibration 

assembly).
Page 196 of 200

10.1.4 Up-Scale Calibration Error. The mean of the difference of 

the “measurement data phase” readings from the reported standard 

gas value must be less than or equal to ± 5 percent or ± 1 ppm

for CO or ± 0.5 percent O2, whichever is less restrictive, 

respectively. The maximum allowable deviation from the mean 

measured value of any single "measurement data phase" reading 

must be less than or equal to ± 2 percent or ± 1 ppm for CO or 

± 0.5 percent O2, whichever is less restrictive, respectively.

10.2 Post-Sampling Calibration Check. Conduct a stack gas postsampling calibration check after the stack gas sampling run or 

set of runs and within 12 hours of the initial calibration. 

Conduct up-scale and zero calibration checks using the protocol 

in Section 10.1. Make no changes to the sampling system or EC 

cell calibration until all post-sampling calibration checks have 

been recorded. If either the zero or up-scale calibration error 

exceeds the respective specification in Sections 10.1.2 and 

10.1.4 then all measurement data collected since the previous 

successful calibrations are invalid and re-calibration and resampling are required. If the sampling system is disassembled or

the EC cell calibration is adjusted, repeat the calibration 

check before conducting the next analyzer sampling run.

11.0 Analytical Procedure 

The analytical procedure is fully discussed in Section 8.

12.0 Calculations and Data Analysis
Page 197 of 200

Determine the CO and O2 concentrations for each stack gas 

sampling run by calculating the mean gas concentrations of the 

data recorded during the “measurement data phase”. 

13.0 Protocol Performance

Use the following protocols to verify consistent analyzer 

performance during each field sampling day.

13.1 Measurement Data Phase Performance Check. Calculate the 

mean of the readings from the “measurement data phase”. The 

maximum allowable deviation from the mean for each of the 

individual readings is ± 2 percent, or ± 1 ppm, whichever is 

less restrictive. Record the mean value and maximum deviation 

for each gas monitored. Data must conform to Section 10.1.4. The 

EC cell flow rate must conform to the specification in Section 

8.3.

Example: A measurement data phase is invalid if the maximum 

deviation of any single reading comprising that mean is greater 

than ± 2 percent or ± 1 ppm (the default criteria). For example, 

if the mean = 30 ppm, single readings of below 29 ppm and above 

31 ppm are disallowed).

13.2 Interference Check. Before the initial use of the EC cell 

and interference gas scrubber in the field, and semi-annually 

thereafter, challenge the interference gas scrubber with NO and 

NO2 gas standards that are generally recognized as representative 

of diesel-fueled engine NO and NO2 emission values. Record the 
Page 198 of 200

responses displayed by the CO EC cell and other pertinent data 

on Figure 1 or a similar form. 

13.2.1 Interference Response. The combined NO and NO2

interference response should be less than or equal to ± 5 

percent of the up-scale CO calibration gas concentration. 

13.3 Repeatability Check. Conduct the following check once for 

each nominal range that is to be used on the CO EC cell within 

five days prior to each field sampling program. If a field

sampling program lasts longer than five days, repeat this check 

every five days. Immediately repeat the check if the EC cell is 

replaced or if the EC cell is exposed to gas concentrations 

greater than 150 percent of the highest up-scale gas 

concentration.

13.3.1 Repeatability Check Procedure. Perform a complete EC cell 

sampling run (all three phases) by introducing the CO 

calibration gas to the measurement system and record the 

response. Follow Section 10.1.3. Use Figure 1 to record all 

data. Repeat the run three times for a total of four complete 

runs. During the four repeatability check runs, do not adjust 

the system except where necessary to achieve the correct 

calibration gas flow rate at the analyzer.

13.3.2 Repeatability Check Calculations. Determine the highest 

and lowest average “measurement data phase” CO concentrations

from the four repeatability check runs and record the results on 
Page 199 of 200

Figure 1 or a similar form. The absolute value of the difference 

between the maximum and minimum average values recorded must not 

vary more than ± 3 percent or ± 1 ppm of the up-scale gas value,

whichever is less restrictive.

14.0 Pollution Prevention (Reserved)

15.0 Waste Management (Reserved)

16.0 Alternative Procedures (Reserved)

17.0 References

(1) “Development of an Electrochemical Cell Emission Analyzer 

Test Protocol”, Topical Report, Phil Juneau, Emission 

Monitoring, Inc., July 1997.

(2) “Determination of Nitrogen Oxides, Carbon Monoxide, and 

Oxygen Emissions from Natural Gas-Fired Engines, Boilers, and 

Process Heaters Using Portable Analyzers”, EMC Conditional Test 

Protocol 30 (CTM-30), Gas Research Institute Protocol GRI96/0008, Revision 7, October 13, 1997.

(3) "ICAC Test Protocol for Periodic Monitoring”, EMC 

Conditional Test Protocol 34 (CTM-034), The Institute of Clean 

Air Companies, September 8, 1999.

(4) “Code of Federal Regulations”, Protection of Environment, 

40 CFR, Part 60, Appendix A, Methods 1-4; 10.

Table 1: Appendix A - Sampling Run Data.

Facility________________ Engine I.D.______________ Date_________
Page 200 of 200

Run Type: (__) (__) (__) (__)

 (X) Pre-Sample Stack Gas Post-Sample Repeatability

 Calibration Sample Cal. Check Check

 

Run # 1 1 2 2 3 3 4 4 Time Scrub.

OK 

FlowRate

Gas O2 CO O2 CO O2 CO O2 CO

Sample 

Cond.

Phase

“

“

“

“

 

Measurement

Data 

Phase

“

“

“

“

“

“

“

“

“ 

“

 Mean

Refresh

Phase

“

“

“

“