6560-50-P 

ENVIRONMENTAL PROTECTION AGENCY 

40 CFR Part 63 

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

RIN 2060-AP36 

National Emission Standards for Hazardous Air Pollutants for 

Reciprocating Internal Combustion Engines 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Final rule. 

SUMMARY: EPA is promulgating national emission standards for 

hazardous air pollutants for existing stationary compression 

ignition reciprocating internal combustion engines that either 

are located at area sources of hazardous air pollutant emissions 

or that have a site rating of less than or equal to 500 brake 

horsepower and are located at major sources of hazardous air 

pollutant emissions. In addition, EPA is promulgating national 

emission standards for hazardous air pollutants for existing 

non-emergency stationary compression ignition engines greater 

than 500 brake horsepower that are located at major sources of 

hazardous air pollutant emissions. Finally, EPA is revising the 

provisions related to startup, shutdown, and malfunction for the 

engines that were regulated previously by these national 

emission standards for hazardous air pollutants. 
2 

DATES: This final rule is effective on [INSERT DATE 60 DAYS 

AFTER PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: EPA has established a docket for this action under 

Docket ID No. EPA-HQ-OAR-2008-0708. EPA also relies on 

materials in Docket ID Nos. EPA-HQ-OAR-2002-0059, EPA-HQ-OAR2005-0029, and EPA-HQ-OAR-2005-0030 and incorporates those 

dockets into the record for the final rule. All documents in 

the docket are listed on the www.regulations.gov web site. 

Although listed in the index, some information is not publicly 

available, e.g., Confidential Business Information (CBI) or 

other information whose disclosure is restricted by statute. 

Certain other material, such as copyrighted material, is not 

placed on the Internet and will be publicly available only in 

hard copy form. Publicly available docket materials are 

available either electronically through www.regulations.gov or 

in hard copy at the EPA Headquarters Library, Room Number 3334, 

EPA West Building, 1301 Constitution Ave., NW, Washington, DC. 

The EPA/DC Public Reading Room hours of operation will be 8:30 

a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through 

Friday. The telephone number for the Public Reading Room is 

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

Radiation Docket and Information Center is (202) 566-1742. 

FOR FURTHER INFORMATION CONTACT: Ms. Melanie King, Energy 

Strategies Group, Sector Policies and Programs Division (D243-
3 

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: Background Information Document. On 

March 5, 2009 (71 FR 9698), EPA proposed national emission 

standards for hazardous air pollutants (NESHAP) for existing 

stationary reciprocating internal combustion engines (RICE) that 

either are located at area sources of hazardous air pollutants 

(HAP) emissions or that have a site rating of less than or equal 

to 500 brake horsepower (HP) and are located at major sources of 

HAP emissions. In addition, EPA proposed national emission 

standards for HAP for existing stationary compression ignition 

(CI) engines greater than 500 brake HP that are located at major 

sources. A summary of the public comments on the proposal and 

EPA’s responses to the comments, as well as the Regulatory 

Impact Analysis Report, are available in Docket ID No. EPA–HQ–

OAR–2008–0708.

Organization of This Document. The following outline is 

provided to aid in locating information in the preamble. 

I. General Information 

A. Does this action apply to me? 

B. Where can I get a copy of this document? 

C. Judicial Review 

D. Why is EPA not promulgating a final decision for spark 

ignition engines? 

II. Background 

III. Summary of the Final Rule 

A. What is the source category regulated by the final rule? 
4 

B. What are the pollutants regulated by the final rule? 

C. What are the final requirements? 

D. What are the operating limitations? 

E. What are the requirements for demonstrating compliance? 

F. What are the reporting and recordkeeping requirements? 

IV. Summary of Significant Changes Since Proposal 

A. Applicability 

B. Final Emission Standards 

C. Management Practices 

D. Startup, Shutdown and Malfunction 

E. Other 

V. Summary of Responses to Major Comments 

A. Applicability 

B. Final Emission Requirements 

C. Management Practices 

D. Startup, Shutdown and Malfunction 

E. Emergency Engines 

F. Emissions Data 

G. Final Rule Impacts 

VI. 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 economic impacts? 

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

impacts? 

VII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 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. 

K. Congressional Review Act 

I. General Information

A. Does this action apply to me?
5 

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 

this final rule. 

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 final 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. 

B. Where can I get a copy of this document?

In addition to being available in the docket, an electronic 

copy of this final action will also be available on the 

Worldwide Web (WWW) through the Technology Transfer Network 

(TTN). Following signature, a copy of this final action will be 

posted on the TTN’s policy and guidance page for newly proposed 
6 

or promulgated rules at the following address: 

http://www.epa.gov/ttn/oarpg/. The TTN provides information and 

technology exchange in various areas of air pollution control. 

C. Judicial Review

Under section 307(b)(1) of the Clean Air Act (CAA), 

judicial review of this final rule is available only by filing a 

petition for review in the U.S. Court of Appeals for the 

District of Columbia Circuit by [INSERT DATE 60 DAYS AFTER 

PUBLICATION OF FINAL RULE IN FEDERAL REGISTER]. Under section 

307(d)(7)(B) of the CAA, only an objection to this final rule 

that was raised with reasonable specificity during the period 

for public comment can be raised during judicial review. 

Moreover, under section 307(b)(2) of the CAA, the requirements 

established by this final rule may not be challenged separately 

in any civil or criminal proceedings brought by EPA to enforce 

these requirements. 

Section 307(d)(7)(B) of the CAA further provides that 

“[o]nly an objection to a rule or procedure which was raised 

with reasonable specificity during the period for public comment 

(including any public hearing) may be raised during judicial 

review.” This section also provides a mechanism for us to 

convene a proceeding for reconsideration, “[i]f the person 

raising an objection can demonstrate to EPA that it was 

impracticable to raise such objection within [the period for 
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public comment] or if the grounds for such objection arose after 

the period for public comment (but within the time specified for 

judicial review) and if such objection is of central relevance 

to the outcome of the rule.” Any person seeking to make such a 

demonstration to us should submit a Petition for Reconsideration 

to the Office of the Administrator, U.S. EPA, Room 3000, Ariel 

Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 

20460, with a copy to both the person(s) listed in the preceding 

FOR FURTHER INFORMATION CONTACT section, and the Associate 

General Counsel for the Air and Radiation Law Office, Office of 

General Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania 

Ave., NW., Washington, DC 20460. 

D. Why is EPA not promulgating a final decision for spark 

ignition engines?

In the notice of proposed rulemaking for this rule, 

published on March 5, 2009, EPA proposed the NESHAP for all 

existing stationary RICE located at area sources of HAP 

emissions and existing stationary RICE that had a site rating of 

less than or equal to 500 brake HP and located at major sources 

of HAP emissions. Also, EPA proposed NESHAP for existing 

stationary CI engines greater than 500 brake HP located at major 

sources. 

During the comment period following the proposal, EPA 

received a number of comments stating that EPA had insufficient 
8 

emissions data for existing spark ignition (SI) engines. 

Because commenters believed that EPA had inadequate emissions 

data for SI engines, they suggested that EPA should consider 

seeking an extension of its February 10, 2010 consent decree 

deadline to allow additional time for the collection of 

emissions data for SI engines. Several commenters indicated 

that they would work with EPA to gather the necessary test data 

to obtain adequate and sufficient emissions tests for SI 

engines. Among other things, the commenters noted that 

developing the final requirements for SI engines later in 2010 

would provide sufficient time for industry to develop test 

programs, conduct testing of engines, assemble test results, and 

submit the complete results to EPA for review. Other commenters 

requested that EPA seek a one year extension of its consent 

decree deadline for SI engines, which would mean a final rule 

for these engines by February 10, 2011. 

In consideration of the comments, EPA sought and obtained a 

six month extension of its February 10, 2010 deadline for SI 

engines. EPA maintains that this period is sufficient for the 

commenters to provide additional test data for the SI engines. 

Thus, pursuant to the revised consent decree between EPA and 

Sierra Club, EPA will finalize requirements for existing 

stationary SI engines that are less than or equal to 500 HP and 

located at major sources of HAP emissions and existing 
9 

stationary SI engines that are located at area sources of HAP 

emissions by August 10, 2010. For these reasons, this final 

rule does not contain standards for existing stationary SI 

engines that are less than or equal to 500 HP and located at 

major sources of HAP emissions and existing stationary SI 

engines that are located at area sources of HAP emissions. 

Consistent with the original consent decree, EPA is 

finalizing regulations for existing stationary CI engines that 

are less than or equal to 500 HP and located at major sources 

and existing stationary CI engines that are located at area 

sources in this final rule. EPA is also promulgating 

requirements for existing stationary non-emergency CI engines 

that are greater than 500 HP and located at major sources. 

EPA plans to continue to work with affected stakeholders 

over the next several months in order to obtain more complete 

emissions data for existing stationary SI engines. The 

emissions data collected will be analyzed and if EPA’s review 

indicates that the submitted data meets acceptance criteria, EPA 

will include the data in developing final standards. EPA will 

promulgate regulations for existing stationary SI engines by 

August 10, 2010. 

II. Background 

This action promulgates NESHAP for existing stationary CI 

RICE with a site rating of less than or equal to 500 HP located 
10 

at major sources, existing non-emergency CI engines with a site 

rating greater than 500 HP at major sources, and existing 

stationary CI RICE of any power rating located at area sources. 

EPA is finalizing these standards to meet its statutory 

obligation to address HAP emissions from these sources under 

sections 112(d), 112(c)(3) and 112(k) of the CAA. The final 

NESHAP for stationary RICE will be promulgated under 40 CFR part 

63, subpart ZZZZ, which already contains standards applicable to 

new stationary RICE and some existing stationary RICE. 

 EPA promulgated NESHAP for existing, new, and reconstructed 

stationary RICE greater than 500 HP located at major sources on 

June 15, 2004 (69 FR 33474). EPA promulgated NESHAP for new and 

reconstructed stationary RICE that are located at area sources 

of HAP emissions and for new and reconstructed stationary RICE 

that have a site rating of less than or equal to 500 HP that are 

located at major sources of HAP emissions on January 18, 2008 

(73 FR 3568). At that time, EPA did not promulgate final 

requirements for existing stationary RICE that are located at 

area sources of HAP emissions or for existing stationary RICE 

that have a site rating of less than or equal to 500 HP that are 

located at major sources of HAP emissions. Although EPA 

proposed standards for these sources, EPA did not finalize these 

standards due to comments received indicating that the proposed 

Maximum Achievable Control Technology (MACT) determinations for 
11 

existing sources were inappropriate because of a decision by the 

U.S. Court of Appeals for the District of Columbia Circuit on 

March 13, 2007, which vacated EPA’s MACT standards for the Brick 

and Structural Clay Products Manufacturing source category (40 

CFR part 63, subpart JJJJJ). Sierra Club v. EPA, 479 F.3d 875 

(D.C. Cir. 2007). Among other things, the D.C. Circuit found 

that EPA’s no emission reduction MACT determination in the 

challenged rule was unlawful. Because EPA had used a MACT floor 

methodology in the proposed stationary RICE rule similar to the 

methodology used in the Brick MACT, EPA decided to re-evaluate 

the MACT floors for existing major sources that have a site 

rating of less than or equal to 500 brake HP consistent with the 

Court’s decision in the Brick MACT case. Also, EPA has reevaluated the standards for existing area sources in light of 

the comments received on the proposed rule. 

 In addition, stakeholders have encouraged the Agency to 

review whether there are further ways to reduce emissions of 

pollutants from existing stationary diesel engines. In its 

comments on EPA’s 2005 proposed rule for new stationary diesel 

engines (70 FR 39870), the Environmental Defense Fund (EDF) 

suggested several possible avenues for the regulation of 

existing stationary diesel engines, including use of diesel 

oxidation catalysts or catalyzed diesel particulate filters 

(CDPF), as well as the use of ultra low sulfur diesel (ULSD) 
12 

fuel. EDF suggested that such controls can provide significant 

pollution reductions at reasonable cost. EPA issued an advance 

notice of proposed rulemaking (ANPRM) in January 2008, where it 

solicited comment on several issues concerning options to 

regulate emissions of pollutants from existing stationary diesel 

engines, generally, and specifically from larger, older 

stationary diesel engines. EPA solicited comment and collected 

information to aid decision-making related to the reduction of 

HAP emissions from existing stationary diesel engines and 

specifically from larger, older engines under CAA section 112 

authorities. The Agency sought comment on the larger, older 

non-emergency CI engines because available data indicate that 

those engines emit the majority of particulate matter (PM) and 

toxic emissions from non-emergency stationary CI engines as a 

whole. A summary of comments and responses that were received 

on the ANPRM is included in docket EPA-HQ-OAR-2007-0995. EPA 

proposed and is finalizing emissions reductions from existing 

non-emergency stationary diesel engines at major sources that 

have a site rating greater than 500 HP. 

This action also revises the provisions of the existing 

NESHAP as it applies to periods of startup, shutdown, and 

malfunction. This revision affects all stationary engines 

regulated in this NESHAP, including stationary engines that were 

regulated by the 2004 and 2008 NESHAP. The revision of these 
13 

provisions is a result of a Court decision that invalidated 

regulations related to startup, shutdown and malfunction in the 

General Provisions of Part 63 (Sierra Club v. EPA, 551 F.3d 1019 

(D.C. Cir. 2008)). 

III. Summary of the Final Rule

A. What is the source category regulated by the final rule? 

This final rule addresses emissions from existing 

stationary CI engines less than or equal to 500 HP located at 

major sources and all existing stationary CI engines located at 

area sources. This final rule also addresses emissions from 

existing stationary non-emergency CI engines greater than 500 HP 

at major sources. A major source of HAP emissions is generally 

a stationary source that emits or has the potential to emit any 

single HAP at a rate of 10 tons (9.07 megagrams) or more per 

year or any combination of HAP at a rate of 25 tons (22.68 

megagrams) or more per year. An area source of HAP emissions is 

a source that is not a major source. 

This action revises the regulations at 40 CFR part 63, 

subpart ZZZZ, currently applicable to new and reconstructed 

stationary RICE and to existing stationary RICE greater than 500 

HP located at major sources. Through this action, we are adding 

to subpart ZZZZ requirements for: existing CI stationary RICE 

less than or equal to 500 HP located at major sources and 

existing CI stationary RICE located at area sources. 
14 

1. Stationary CI RICE ≤500 HP at Major Sources. 

This action revises 40 CFR part 63, subpart ZZZZ, to 

address HAP emissions from existing stationary CI RICE less than 

or equal to 500 HP located at major sources. For stationary 

engines less than or equal to 500 HP at major sources, EPA must 

determine what is the appropriate MACT for those engines under 

sections 112(d)(2) and (d)(3) of the CAA. 

EPA has divided stationary CI RICE into emergency and nonemergency engines in order to capture the unique differences 

between these types of engines. 

2. Stationary CI RICE at Area Sources. 

This action revises 40 CFR part 63, subpart ZZZZ, in order 

to address HAP emissions from existing stationary RICE located 

at area sources. Section 112(d) of the CAA requires EPA to 

establish NESHAP for both major and area sources of HAP that are 

listed for regulation under CAA section 112(c). As noted above, 

an area source is a stationary source that is not a major 

source. 

Section 112(k)(3)(B) of the CAA calls for EPA to identify 

at least 30 HAP that, as a result of emissions of area sources, 

pose the greatest threat to public health in the largest number 

of urban areas. EPA implemented this provision in 1999 in the 

Integrated Urban Air Toxics Strategy (64 FR 38715, July 19, 

1999). Specifically, in the Strategy, EPA identified 30 HAP 
15 

that pose the greatest potential health threat in urban areas, 

and these HAP are referred to as the “30 urban HAP.” Section 

112(c)(3) of the CAA requires EPA to list sufficient categories 

or subcategories of area sources to ensure that area sources 

representing 90 percent of the emissions of the 30 urban HAP are 

subject to regulation. EPA implemented these requirements 

through the Integrated Urban Air Toxics Strategy (64 FR 38715, 

July 19, 1999). The area source stationary engine source 

category was one of the listed categories. A primary goal of 

the Strategy is to achieve a 75 percent reduction in cancer 

incidence attributable to HAP emitted from stationary sources. 

Under CAA section 112(d)(5), EPA may elect to promulgate 

standards or requirements for area sources “which provide for 

the use of generally available control technologies or 

management practices by such sources to reduce emissions of 

hazardous air pollutants.” Additional information on generally 

available control technologies (GACT) and management practices 

is found in the Senate report on the legislation (Senate report 

Number 101-228, December 20, 1989), which describes GACT as: 

. . . methods, practices and techniques which are 

commercially available and appropriate for application by 

the sources in the category considering economic impacts 

and the technical capabilities of the firms to operate and 

maintain the emissions control systems. 

 

Consistent with the legislative history, EPA can consider costs 

and economic impacts in determining GACT, which is particularly 
16 

important when developing regulations for source categories, 

like this one, that have many small businesses. 

Determining what constitutes GACT involves considering the 

control technologies and management practices that are generally 

available to the area sources in the source category. EPA also 

considers the standards applicable to major sources in the same 

industrial sector to determine if the control technologies and 

management practices are transferable and generally available to 

area sources. In appropriate circumstances, EPA may also 

consider technologies and practices at area and major sources in 

similar categories to determine whether such technologies and 

practices could be considered generally available for the area 

source category at issue. Finally, as EPA has already noted, in 

determining GACT for a particular area source category, EPA 

considers the costs and economic impacts of available control 

technologies and management practices on that category. 

The urban HAP that must be regulated at stationary RICE to 

achieve the CAA section 112(c)(3) requirement to regulate 

categories accounting for 90 percent of the urban HAP are: 7 

polycyclic aromatic hydrocarbons (PAH), formaldehyde, 

acetaldehyde, arsenic, benzene, beryllium compounds, and cadmium 

compounds. As explained below, EPA chose to select formaldehyde 

to serve as a surrogate for HAP emissions. Formaldehyde is the 

hazardous air pollutant present in the highest concentration 
17 

from stationary engines. In addition, emissions data show that 

formaldehyde emission levels are related to other HAP emission 

levels. EPA has previously demonstrated that carbon monoxide 

(CO) is an appropriate surrogate for formaldehyde and is 

consequently finalizing emission standards in terms of CO for 

existing stationary CI RICE at area sources. 

Consistent with existing stationary CI RICE at major 

sources, EPA has also divided the existing stationary CI RICE at 

area sources into emergency and non-emergency engines in order 

to properly take into account the differences between these 

engines. 

3. Stationary CI RICE >500 HP at Major Sources. 

 In addition, EPA is finalizing emission standards for nonemergency stationary CI engines greater than 500 HP at major 

sources. 

B. What are the pollutants regulated by the final rule?

The final rule regulates emissions of HAP. Available 

emissions data show that several HAP, which are formed during 

the combustion process or which are contained within the fuel 

burned, are emitted from stationary engines. The HAP which have 

been measured in emission tests conducted on diesel fired 

stationary RICE include: 1,3-butadiene, acetaldehyde, acrolein, 

benzene, ethylbenzene, formaldehyde, n-hexane, naphthalene, PAH, 

polycyclic organic matter, styrene, toluene, and xylene. 
18 

Metallic HAP from diesel fired stationary RICE that have been 

measured include: cadmium, chromium, lead, manganese, mercury, 

nickel, and selenium. 

EPA described the health effects of these HAP and other HAP 

emitted from the operation of stationary RICE in the preamble to 

40 CFR part 63, subpart ZZZZ, published on June 15, 2004 (69 FR 

33474). More detail on the health effects of these HAP and 

other HAP emitted from the operation of stationary RICE can be 

found in the Regulatory Impact Analysis (RIA) for the final 

rule. These HAP emissions are known to cause, or contribute 

significantly to air pollution, which may reasonably be 

anticipated to endanger public health or welfare. 

The final rule will limit emissions of HAP through 

emissions standards for CO for existing stationary CI RICE. 

Carbon monoxide has been shown to be an appropriate surrogate 

for HAP emissions from CI engines. For the NESHAP promulgated 

in 2004, EPA found that there is a relationship between CO 

emissions reductions and HAP emissions reductions from CI 

stationary engines. Therefore, because testing for CO emissions 

has many advantages over testing for HAP emissions, CO emissions 

were chosen as a surrogate for HAP emissions reductions for CI 

stationary engines. 

For the standards being finalized in this action, EPA 

believes that previous decisions regarding the appropriateness 
19 

of using CO in concentration (parts per million (ppm)) levels as 

has been done for stationary sources before as surrogates for 

HAP are still valid.1

 Consequently, EPA is finalizing emission 

standards for CO for stationary CI engines in order to regulate 

HAP emissions. In addition, EPA is promulgating separate 

provisions relevant to emissions of metallic HAP from existing 

diesel engines, as discussed in section III.C. of this preamble. 

In addition to reducing HAP and CO, the final rule will 

result in the reduction of PM emissions from existing stationary 

diesel engines. The aftertreatment technologies expected to be 

used to reduce HAP and CO emissions also reduce emissions of PM 

from diesel engines. Also, the final rule requires the use of 

ULSD for diesel-fueled stationary non-emergency CI engines 

greater than 300 HP with a displacement of less than 30 liters 

per cylinder. This will result in lower emissions of sulfur 

oxides (SOx) and sulfate particulate from these engines by 

reducing the sulfur content in the fuel. 

C. What are the final requirements?

1. Existing Stationary RICE at Major Sources. 

The numerical emission standards that are being finalized 

in this action for stationary non-emergency CI RICE located at 

major sources are shown in Table 1 of this preamble. The 

 

1

 In contrast, mobile source emission standards for diesel engines (both 

nonroad and on-highway) are promulgated on a mass/bhp-hr basis rather than 

concentration. 
20 

numerical emission standards are in units of ppm by volume, dry 

basis (ppmvd) or percent reduction. 

Table 1. Numerical Emission Standards for Existing Stationary 

CI RICE Located at Major Sources 

Subcategory Except during periods of 

startup 

Non-Emergency CI 

100≤HP≤300 230 ppmvd CO at 15% O2 

Non-Emergency CI 

300<HP≤500 

49 ppmvd CO at 15% O2 

or 

70% CO reduction

Non-Emergency CI 

>500 HP 

23 ppmvd CO at 15% O2 

or 

70% CO reduction 

In addition, certain existing stationary RICE located at 

major sources are subject to fuel requirements. Owners and 

operators of existing stationary non-emergency CI engines 

greater than 300 HP with a displacement of less than 30 liters 

per cylinder located at major sources that use diesel fuel must 

use only diesel fuel meeting the requirements of 40 CFR 

80.510(b). This section requires that diesel fuel have a 

maximum sulfur content of 15 ppm and either a minimum cetane 

index of 40 or a maximum aromatic content of 35 volume percent. 

These fuel requirements are being finalized in order to reduce 

the potential formation of sulfate compounds that are emitted 

when high sulfur diesel fuel is used in combination with 
21 

oxidation catalysts and to assist in the efficient operation of 

the oxidation catalysts. 

EPA is finalizing work practice standards for existing 

stationary emergency CI RICE less than or equal to 500 HP 

located at major sources and existing stationary non-emergency 

CI RICE less than 100 HP located at major sources. Existing 

stationary emergency CI RICE less than or equal to 500 HP 

located at major sources are subject to the following work 

practices: 

• change oil and filter every 500 hours of operation or 

annually, whichever comes first, except that sources can 

extend the period for changing the oil if the oil is part 

of an oil analysis program as discussed below and none of 

the condemning limits are exceeded; 

• inspect air cleaner every 1000 hours of operation or 

annually, whichever comes first; and 

• inspect all hoses and belts every 500 hours of operation or 

annually, whichever comes first, and replace as necessary. 

Existing stationary non-emergency CI RICE less than 100 HP 

located at major sources are subject to the following work 

practices: 

• change oil and filter every 1000 hours of operation or 

annually, whichever comes first, except that sources can 

extend the period for changing the oil if the oil is part 
22 

of an oil analysis program as discussed below and none of 

the condemning limits are exceeded; 

• inspect air cleaner every 1000 hours of operation or 

annually, whichever comes first; and 

• inspect all hoses and belts every 500 hours or annually, 

whichever comes first, and replace as necessary. 

Sources also have the option to use an oil change analysis 

program to extend the oil change frequencies specified above. 

The analysis program must at a minimum analyze the following 

three parameters: Total Base Number, viscosity, and percent 

water content. The analysis must be conducted at the same 

frequencies specified for changing the engine oil. If the 

condemning limits provided below are not exceeded, the engine 

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

the condemning limits are exceeded, the engine owner or operator 

must change the oil. The condemning limits are as follows: 

• Total Base Number is less than 30 percent of the Total 

Base Number of the oil when new; or 

• 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. 

Pursuant to the provisions of 40 CFR 63.6(g), sources can 

also request that the Administrator approve alternative work 
23 

practices. The alternative work practices must be at least as 

stringent as those specified above.

EPA is also including in the final rule additional capture 

and collection requirements to reduce metallic HAP emissions. 

Owners and operators of existing stationary non-emergency CI 

engines greater than 300 HP located at major sources must do one 

of the following if the engine is not already equipped with a 

closed crankcase ventilation system: 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. 

2. Existing Stationary RICE at Area Sources. 

The numerical emission standards that are being finalized 

in this action for stationary CI RICE located at area sources 

are shown in Table 2 of this preamble. Existing stationary 

emergency engines at area sources located at residential, 

commercial, or institutional facilities are not part of the 

source category and therefore are not subject to any 

requirements under this final rule. 

Although existing stationary non-emergency CI RICE greater 

than 300 HP that are located at area sources in Alaska that are 

not accessible by the Federal Aid Highway System (FAHS) do not 
24 

have to meet the CO emission standards specified in Table 2 of 

this preamble, they must meet the management practices discussed 

in this section for non-emergency CI RICE less than or equal to 

300 HP. 

Table 2. Numerical Emission Standards for Existing 

Stationary RICE Located at Area Sources

Subcategory Except during periods of 

startup 

Non-Emergency CI 

300<HP≤500 

49 ppmvd CO at 15% O2 

or 

70% CO reduction

Non-Emergency CI 

>500 HP 

23 ppmvd CO at 15% O2 

or 

70% CO reduction 

Also, owners and operators of existing stationary nonemergency CI engines greater than 300 HP with a displacement of 

less than 30 liters per cylinder located at area sources that 

use diesel fuel must use only diesel fuel meeting the 

requirements of 40 CFR 80.510(b). This section requires that 

diesel fuel have a maximum sulfur content of 15 ppm and either a 

minimum cetane index of 40 or a maximum aromatic content of 35 

volume percent. 

EPA is finalizing management practices for existing 

stationary emergency CI RICE located at area sources and 

existing stationary non-emergency CI RICE less than or equal to 
25 

300 HP located at area sources. Existing stationary emergency 

CI RICE located at area sources are subject to the following 

management practices: 

• change oil and filter every 500 hours of operation or 

annually, whichever comes first, except that sources can 

extend the period for changing the oil if the oil is part 

of an oil analysis program as discussed below and the 

condemning limits are not exceeded; 

• inspect air cleaner every 1000 hours of operation or 

annually, whichever comes first; and 

• inspect all hoses and belts every 500 hours of operation or 

annually, whichever comes first, and replace as necessary. 

Existing stationary non-emergency CI RICE less than or equal to 

300 HP located at area sources are subject to the following 

management practices: 

• change oil and filter every 1000 hours of operation or 

annually, whichever comes first, except that sources can 

extend the period for changing the oil if the oil is part 

of an oil analysis program as discussed below and the 

condemning limits are not exceeded; 

• inspect air cleaner every 1000 hours of operation or 

annually, whichever comes first; and 

• inspect all hoses and belts every 500 hours or annually, 
26 

whichever comes first, and replace as necessary. 

As discussed above for major sources, these sources may utilize 

an oil analysis program in order to extend the specified oil 

change requirement specified above. Also, sources have the 

option to work with state permitting authorities pursuant to 

EPA’s regulations at 40 CFR subpart E (‘‘Approval of State 

Programs and Delegation of Federal Authorities’’) for approval 

of alternative management practices. Subpart E implements 

section 112(l) of the CAA, which authorizes EPA to approve 

alternative state/local/tribal HAP standards or programs when 

such requirements are demonstrated to be no less stringent than 

EPA promulgated standards. Sources may also petition the 

Administrator to revise the rule to provide alternative

management practices. The alternative management practices must 

be at least as stringent as those specified above.

Finally, in order to reduce metallic HAP emissions, 

existing stationary non-emergency CI engines greater than 300 HP 

located at area sources must do one of the following if the 

engine is not already equipped with a closed crankcase 

ventilation system: 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 
27 

crankcase by filtering the exhaust stream to remove oil mist, 

particulates, and metals. 

3. Startup Requirements 

The following stationary engines are subject to specific 

operational standards during engine startup: 

• Existing CI RICE less than or equal to 500 HP located at 

major sources, 

• Existing non-emergency CI RICE greater than 500 HP located 

at major sources, 

• Existing CI RICE located at area sources, 

• New or reconstructed non-emergency two-stroke lean burn 

(2SLB) >500 HP located at a major source of HAP emissions, 

• New or reconstructed non-emergency four-stroke lean burn 

(4SLB) >=250 HP located at a major source of HAP emissions, 

• Existing non-emergency four-stroke rich burn (4SRB) >500 HP 

located at a major source of HAP emissions, 

• New or reconstructed non-emergency 4SRB >500 HP located at 

a major source of HAP emissions, and 

• New or reconstructed non-emergency CI >500 HP located at a 

major source of HAP emissions. 

Engine startup is defined as the time from initial start until 

applied load and engine and associated equipment reaches steady 

state or normal operation. For stationary engines with 
28 

catalytic controls, engine startup means the time from initial 

start until applied load and engine and associated equipment 

reaches steady state, or normal operation, including the 

catalyst. Owners and operators must minimize the engine’s time 

spent at idle and minimize the engine’s startup to a period 

needed for appropriate and safe loading of the engine, not to 

exceed 30 minutes, after which time the engine must meet the 

otherwise applicable emission standards. These requirements 

will limit the HAP emissions during periods of engine 

startup.non-startup emission limitations apply. Pursuant to the 

provisions of 40 CFR 63.6(g), engines at major sources may 

petition the Administrator for an alternative work practice. An 

owner or operator of an engine at an area source can work with 

its state permitting authority pursuant to EPA’s regulations at 

40 CFR subpart E for approval of an alternative management 

practice. See 40 C.F.R. Subpart E (setting forth requirements 

for, among other things, equivalency by permit, rule 

substitution). Such alternative work or management practice must 

be demonstrated to be no less stringent than EPA promulgated

standards. These requirements will limit the HAP emissions 

during periods of engine startup.

D. What are the operating limitations? 

 In addition to the standards discussed above, EPA is 

finalizing operating limitations for stationary non-emergency CI 
29 

RICE that are greater than 500 HP. Owners and operators of 

engines that are equipped with oxidation catalyst must maintain 

the 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. Owners and operators of these engines must 

also maintain the temperature of the stationary RICE exhaust so 

that the catalyst inlet temperature is between 450 and 1350 

degrees Fahrenheit (°F). Owners and operators may petition for 

a different temperature range; the petition must demonstrate why 

it is operationally necessary and appropriate to operate below 

the temperature range specified in the rule (see 40 CFR 

63.8(f)).. Owners and operators of engines that are not using 

oxidation catalyst must comply with any operating limitations 

approved by the Administrator. 

 Owners and operators of existing stationary non-emergency 

CI engines greater than 300 HP meeting the requirement to use 

open or closed crankcases 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. 

E. What are the requirements for demonstrating compliance?
30 

 The following sections describe the requirements for 

demonstrating compliance under the final rule. 

1. Existing Stationary CI RICE at Major Sources. 

 Owners and operators of existing stationary non-emergency 

CI RICE located at major sources that are less than 100 HP and 

stationary emergency CI RICE located at major sources must 

operate and maintain their stationary RICE and aftertreatment 

control device (if any) according to the manufacturer’s 

emission-related written instructions or develop their own 

maintenance plan. Owners and operators of existing stationary 

non-emergency CI RICE located at major sources that are less 

than 100 HP and existing stationary emergency CI RICE located at 

major sources do not have to conduct any performance testing 

because they are not subject to numerical emission standards. 

Owners and operators of existing stationary non-emergency 

CI RICE located at major sources that are greater than or equal 

to 100 HP and less than or equal to 500 HP must conduct an 

initial performance test to demonstrate that they are achieving 

the required emission standards. 

Owners and operators of existing stationary non-emergency 

CI RICE greater than 500 HP located at major sources must 

conduct an initial performance test and must test every 8,760 

hours of operation or 3 years, whichever comes first, to 

demonstrate that they are achieving the required emission 
31 

standards. 

Owners and operators of stationary non-emergency CI RICE 

that are greater than 500 HP and are located at a major source 

must continuously monitor and record the catalyst inlet 

temperature if an oxidation catalyst is being used on the 

engine. The pressure drop across the catalyst must also be 

measured monthly. If an oxidation catalyst is not being used on 

the engine, the owner or operator must continuously monitor and 

record the operating parameters (if any) approved by the 

Administrator. 

On October 9, 2008 (73 FR 59956), EPA proposed performance 

specification requirements for continuous parametric monitoring 

systems (CPMS). Currently there are no performance 

specifications for the CPMS that are required for continuously 

monitoring the catalyst inlet temperature. The timetable for 

finalizing the proposed performance specification requirements 

is uncertain; therefore, EPA plans to finalize performance 

specification requirements in 40 CFR part 63, subpart ZZZZ for 

the CPMS systems used for continuous catalyst inlet temperature 

monitoring when the final requirements are promulgated for 

existing SI engines in August 2010. 

2. Existing Stationary RICE at Area Sources. 

Owners and operators of existing stationary RICE located at 

area sources that are subject to management practices, as shown 
32 

in Table 2 of this preamble, must develop a maintenance plan 

that specifies how the management practices will be met. Owners 

and operators of existing stationary RICE that are subject to 

management practices do not have to conduct any performance 

testing. 

Owners and operators of existing stationary non-emergency 

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

must conduct an initial performance test to demonstrate that 

they are achieving the required emission standards. 

Owners and operators of existing stationary non-emergency 

RICE that are greater than 500 HP and located at area sources 

must conduct an initial performance test and must test every 

8,760 hours of operation or 3 years, whichever comes first, to 

demonstrate that they are achieving the required emission 

standards. 

Owners and operators of existing stationary non-emergency 

CI RICE that are greater than 500 HP and are located at an area 

source must continuously monitor and record the catalyst inlet 

temperature if an oxidation catalyst is being used on the 

engine. The pressure drop across the catalyst must also be 

measured monthly. If an oxidation catalyst is not being used on 

the engine, the owner or operator must continuously monitor and 

record the operating parameters (if any) approved by the 

Administrator. 
33 

F. What are the reporting and recordkeeping requirements?

 The following sections describe the reporting and 

recordkeeping requirements that are required under the final 

rule. 

Owners and operators of existing stationary emergency RICE 

that do not meet the requirements for non-emergency engines are 

required to keep records of their hours of operation. Owners 

and operators of existing stationary emergency RICE must install 

a non-resettable hour meter on their engines to record the hours 

of operation of the engine. Emergency stationary RICE may be 

operated for the purpose of maintenance checks and readiness 

testing, provided that the tests are recommended by the Federal, 

State or local government, the manufacturer, the vendor, or the 

insurance company associated with the engine. Maintenance 

checks and readiness testing of such units are limited to 100 

hours per year. There is no time limit on the use of emergency 

stationary engines in emergency situations; however, the owner 

or operator is required to record the length of operation and 

the reason the engine was in operation during that time. 

Records must be maintained documenting why the engine was 

operating to ensure the 100 hours per year limit for maintenance 

and testing operation is not exceeded. In addition, owners and 

operators are allowed to operate their stationary emergency RICE 

for non-emergency purposes for 50 hours per year, but those 50 
34 

hours are counted towards the total 100 hours provided for 

operation other than for true emergencies. The 50 hours per 

year for non-emergency purposes cannot be used to generate 

income for a facility, for example, to supply power to an 

electric grid or otherwise supply power as part of a financial 

arrangement with another entity. However, owners and operators 

may operate the emergency engine for a maximum of 15 hours per 

year as part of a demand response program if the regional 

transmission organization or equivalent balancing authority and 

transmission operator has determined there are emergency 

conditions that could lead to a potential electrical blackout, 

for example unusually low frequency, equipment overload, 

capacity or energy deficiency, or unacceptable voltage level. 

The engine may not be operated for more than 30 minutes prior to 

the time when the emergency condition is expected to occur, and 

the engine operation must be terminated immediately after the 

facility is notified that the emergency condition is no longer 

imminent. The 15 hours per year of demand response operation 

are counted as part of the 50 hours of operation per year 

provided for non-emergency situations. Owners and operators 

must keep records showing how they were notified of the 

emergency condition and by whom, and the time that the engine 

was operated as part of demand response. 

Owners and operators of existing stationary CI RICE located 
35 

at area sources that are subject to management practices as 

shown in Table 2 of this preamble are required to keep records 

that show that management practices that are required are being 

met. These records must include, at a minimum: oil and filter 

change dates and corresponding hour on the hour meter; 

inspection and replacement dates for air cleaners, hoses, and 

belts; and records of other emission-related repairs and 

maintenance performed. 

Owners and operators of existing non-emergency stationary 

CI RICE greater than 300 HP must keep records of the 

manufacturer’s recommended maintenance procedures for the closed 

crankcase ventilation system or open crankcase filtration system 

and records of the maintenance performed on the system. 

In terms of reporting requirements, owners and operators of 

existing stationary RICE, except stationary RICE that are less 

than 100 HP, existing emergency stationary RICE, and existing 

stationary RICE that are not subject to numerical emission 

standards, must submit all of the applicable notifications as 

listed in the NESHAP General Provisions (40 CFR part 63, subpart 

A), including an initial notification, notification of 

performance test, and a notification of compliance for each 

stationary RICE which must comply with the specified emission 

limitations. 

IV. Summary of Significant Changes Since Proposal 
36 

Most of the rationale used to develop the proposed rule 

remains the same for the final rule. Therefore, the rationale 

previously provided in the preamble to the proposed rule is not 

repeated in the final rule, and the rationale sections of the 

rule, as proposed, should be referred to. Major changes that 

have been made to the rule since proposal are discussed in this 

section with rationale following in the Summary of Responses to 

Major Comments section. 

A. Applicability

EPA proposed to regulate HAP emissions from existing 

stationary engines less than or equal to 500 HP located at major 

sources and all existing stationary engines located at area 

sources. EPA also proposed NESHAP for existing stationary nonemergency CI engines greater than 500 HP that are located at 

major sources. 

In the final rule, EPA is only regulating HAP emissions 

from existing stationary CI engines. EPA will address HAP 

emissions from existing stationary SI engines in a separate 

rulemaking later this year. 

Another change from the proposal is that the final rule is 

not applicable to existing stationary emergency engines at area 

sources that are located at residential, commercial, or 

institutional facilities. These engines are not subject to any 

requirements under the final rule because they are not part of 
37 

the regulated source category. EPA has found that existing 

stationary emergency engines located at residential, commercial, 

and institutional facilities that are area sources were not 

included in the original Urban Air Toxics Strategy inventory and 

were not included in the listing of urban area sources. More 

information on this issue can be found in the memorandum 

entitled “Analysis of the Types of Engines Used to Estimate the 

CAA Section 112(k) Area Source Inventory for Stationary 

Reciprocating Internal Combustion Engines,” available from the 

rulemaking docket. 

B. Final Emission Standards

1. Existing Stationary CI Engines <100 HP Located at Major 

Sources 

For the proposed rule, EPA required existing stationary 

engines less than 50 HP that are located at major sources to 

meet a formaldehyde emission standard. EPA is not finalizing a 

formaldehyde emission standard for stationary CI engines less 

than 50 HP, but is instead requiring compliance with a work 

practice. In addition, in light of several comments asserting 

that the level at which we subcategorized small engines at major 

sources was inappropriate, EPA is finalizing a work practice 

standard for engines less than 100 HP. 

In the proposed rule, existing stationary CI engines less 

than 100 HP located at major sources were required to meet a 40 
38 

ppmvd CO at 15 percent oxygen (O2) standard. In the final rule, 

all existing stationary CI engines less than 100 HP located at 

major sources must meet work practices. These work practices 

are described in section III.C. of this preamble. EPA believes 

that work practices are appropriate and justified for this group 

of stationary engines because the application of measurement 

methodology is not practicable due to technological and economic 

limitations. Further information on EPA’s decision can be found 

in section V.B. below and in the memorandum entitled “MACT Floor 

Determination for Existing Stationary Non-Emergency CI RICE Less 

Than 100 HP and Existing Stationary Emergency CI RICE Located at 

Major Sources and GACT for Existing Stationary CI RICE Located 

at Area Sources,” which is available from the rulemaking docket. 

2. Existing Stationary Non-Emergency CI Engines 100≤HP≤300 

EPA is finalizing a CO emission standard for existing 

stationary non-emergency CI engines greater than or equal to 100 

HP and less than or equal to 300 HP located at major sources of 

230 ppmvd CO at 15 percent O2 standard. EPA revised the proposed 

CO standard for this group of engines based on additional 

information and data received after the proposal, which led to a 

reevaluation of the MACT floor for these stationary engines. A 

discussion of the final MACT floor determination can be found in 

the memo entitled “MACT Floor and MACT Determination for 

Existing Stationary Non-Emergency CI RICE Greater Than or Equal 
39 

to 100 HP Located at Major Sources,” which is available from the 

rulemaking docket. All existing stationary CI engines less than 

or equal to 300 HP located at area sources, both emergency and 

non-emergency, are subject to management practice standards 

under the final rule, as was proposed. 

3. Existing Stationary Non-Emergency CI Engines >300 HP 

EPA proposed that existing stationary non-emergency CI 

engines greater than 300 HP meet a 4 ppmvd CO at 15 percent O2 

standard or a 90 percent CO reduction standard. Numerous 

commenters indicated that EPA’s dataset was insufficient and 

urged EPA to gather more data to obtain a more complete 

representation of emissions from existing stationary CI engines. 

Commenters also questioned the emission standard setting 

approach that EPA used at proposal and claimed that the proposed 

standards did not take into account emissions variability and 

may not be achievable. For the final rule EPA has obtained 

additional test data for existing stationary CI engines and has 

included this additional data in the MACT floor analysis. EPA 

is also using an approach that better considers emissions 

variability, as discussed in V.B. below. 

In the final rule, EPA is providing owners and operators 

the option of meeting either a CO concentration or a CO percent 

reduction standard. Owners and operators of existing stationary 

non-emergency CI engines greater than 300 HP and less than or 
40 

equal to 500 HP located at major and area sources must either 

reduce CO emissions by at least 70 percent or limit the 

concentration of CO in the engine exhaust to 49 ppmvd, at 15 

percent O2. Owners and operators of existing stationary nonemergency CI engines greater than 500 HP located at major and 

area sources must either reduce CO emissions by at least 70 

percent or limit the concentration of CO in the engine exhaust 

to 23 ppmvd, at 15 percent O2. EPA’s review of the data indicate 

that it is appropriate to base the MACT standard on a reduction 

level of 70 percent, which takes into account the variability of 

the emission reduction efficiency of aftertreatment under 

various operational conditions. 

4. Existing Stationary Emergency CI Engines 100≤HP≤500 Located 

at Major Sources 

For existing stationary emergency engines located at major 

sources, we proposed that these engines be subject to a 40 ppmvd 

CO at 15 percent O2 standard. In the final rule, existing 

stationary emergency CI engines greater than or equal to 100 HP 

and less than or equal to 500 HP and located at major sources 

must meet work practices. These work practices are described in 

section III.C. of this preamble. EPA believes that work 

practices are appropriate and justified for this group of 

stationary engines because the application of measurement 

methodology is not practicable due to technological and economic 
41 

limitations. Further information on EPA’s decision can be found 

in the memorandum entitled “MACT Floor Determination for 

Existing Stationary Non-Emergency CI RICE Less Than 100 HP and 

Existing Stationary Emergency CI RICE Located at Major Sources 

and GACT for Existing Stationary CI RICE Located at Area 

Sources,” which is available from the rulemaking docket.

5. Existing Stationary Emergency CI Engines >500 HP Located at 

Area Sources 

For existing stationary emergency engines located at area 

sources, EPA reevaluated the information available for emergency 

engines and considered extensive input received from industry 

and other groups who asserted that the proposed standards were 

not GACT for emergency engines at area sources. In the final 

rule, as discussed below in section V.B., all existing 

stationary emergency CI engines located at area sources must 

meet management practice standards. 

C. Management Practices

 EPA proposed management practices for several subcategories 

of engines located at area sources. EPA explained that the 

proposed management practices would be expected to ensure that 

emission control systems are working properly and would help 

minimize HAP emissions from the engines. EPA proposed specific 

maintenance practices and asked for comments on the need and 

appropriateness for those procedures. Based on feedback 
42 

received during the public comment period, which included 

information submitted in comment letters and additional 

information EPA received following the close of the comment 

period from different industry groups, EPA is finalizing 

management practices for existing stationary non-emergency CI 

engines less than or equal to 300 HP located at area sources and 

all existing emergency stationary CI engines located at area 

sources. 

 Existing stationary non-emergency CI engines less than or 

equal to 300 HP located at area sources are required to change 

the oil and filter every 1,000 hours of operation or annually, 

whichever comes first, inspect air cleaner every 1,000 hours of 

operation or annually, whichever comes first, and inspect all 

hoses and belts every 500 hours of operation or annually, 

whichever comes first, and replace as necessary. Existing 

emergency stationary CI engines located at area sources are 

required under the final rule to change the oil and filter every 

500 hours of operation or annually, whichever comes first, 

inspect air cleaner every 1000 hours of operation or annually, 

whichever comes first, and inspect all hoses and belts every 500 

hours of operation or annually, whichever comes first, and 

replace as necessary. EPA is adding an option for sources to 

use an oil change analysis program to extend the oil change 

frequencies specified above. The analysis program must at a 
43 

minimum analyze the following three parameters: Total Base 

Number, viscosity, and percent water content. If the condemning 

limits provided below 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. The condemning limits are as follows: 

• Total Base Number is less than 30 percent of the Total 

Base Number of the oil when new; or 

• 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. 

Owners and operators of all engines subject to management 

practices also have the option to work with state permitting 

authorities pursuant to EPA’s regulations at 40 CFR subpart E 

for alternative maintenance practices to be used instead of the 

specific maintenance practices promulgated in this rule. The 

maintenance practices must be at least as stringent as those 

specified in the final rule. 

The final rule specifies that in situations where an 

emergency engine is operating during an emergency and it is not 

possible to shut down the engine in order to perform the work or 

management practice requirements on the schedule required in the 

final rule, or if performing the work or management practice on 

the required schedule would otherwise pose an unacceptable risk 
44 

under federal, state, or local law, the maintenance activity can 

be delayed until the emergency is over or the unacceptable risk 

under federal, state, or local law has abated. The maintenance 

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 that defined the unacceptable risk.

D. Startup, Shutdown and Malfunction

EPA proposed formaldehyde and CO emission standards for 

existing stationary engines at major sources to apply during 

periods of startup and malfunction. EPA also proposed certain 

standards for existing stationary engines at area sources that 

would apply during startup and malfunction. Based on various 

comments and concerns with the proposed emission standards for 

periods of startup, EPA has determined that it is not feasible 

to finalize numerical emission standards that would apply during 

startup because the application of measurement methodology to 

this operation is not practicable due to technological and 

economic limitations, as discussed in detail in section V.D. 

As a result, EPA is promulgating operational standards 

during startup that specify that owners and operators must limit 

the engine startup time to no more than 30 minutes and must 

minimize the engine’s time spent at idle during startup. Based 
45 

on information reviewed by EPA, engine startup typically 

requires no more than 30 minutes. We received comments 

indicating that there are conditions where it may take more than 

30 minutes to startup the engine, for example for cold starts or 

where the ambient conditions are very cold. However, commenters 

did not provide enough specificity in their comments, nor did 

commenters provide data, to determine whether any scenarios were 

appropriate to allow a longer startup period. Owners and 

operators of engines at major sources have the option to 

petition the Administrator pursuant to 40 CFR 63.6(g) for 

alternative work practices. Any petition must be based on 

specific factual information indicating the reason the 

alternative work practice is necessary for that engine and is no 

less stringent than startupstart-up requirements in the rule. 

An owner or operator of an engine at an area source can work 

with its state permitting authority pursuant to EPA’s 

regulations at 40 CFR subpart E for approval of an alternative 

management practice, based on specific factual information 

indicating the reason that an alternative management practice

longer period is necessary for that engine. Such alternative 

management practice must be demonstrated to be no less stringent 

than EPA promulgated standards. 

As discussed further below, in section V.D., EPA is not 

setting separate standards for malfunctions in this rule. 
46 

Therefore, the standards that apply during normal operation also 

apply during malfunction. EPA believes that any emissions 

occurring during a malfunction would be of such a short duration 

compared to the emissions averaged during overall testing time 

(three one-hour runs) that the engine would still be able to 

comply with the emission standard. In addition, EPA does not 

view malfunction as a distinct operating mode and, therefore, 

any emissions that occur at such times do not need to be taken 

into account in setting CAA section 112(d) standards. Further, 

as is explained in more detail in Section V.D. below, even if 

malfunctions were considered a distinct operating mode, we 

believe it would be impracticable to take into account 

malfunctions in setting CAA section 112(d) standards. 

E. Other

 EPA is including an additional requirement in the final 

rule that will reduce metallic HAP emissions. Owners and 

operators of existing stationary non-emergency CI engines 

greater than 300 HP must do one of the following if the engine 

is not already equipped with a closed crankcase ventilation 

system: 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 the crankcase emissions by filtering 

the exhaust stream to remove oil mist, particulates, and metals. 
47 

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. 

EPA is including special provisions in the final rule for 

existing stationary non-emergency CI RICE greater than 300 HP 

located at area sources in Alaska not accessible by the FAHS. 

Owners and operators of these engines do not have to meet the CO 

emission standards specified in Table 2 of this preamble, but 

must instead meet the management practices that are described 

for stationary non-emergency CI RICE less than or equal to 300 

HP in section III.C. of this preamble. 

The final rule specifies that stationary CI engines that 

are used to startup combustion turbines should meet the same 

requirements as stationary emergency CI engines. 

V. Summary of Responses to Major Comments 

A more detailed summary of comments and EPA’s responses can 

be found in the document named “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 
48 

500 Brake HP Located at Major Sources of Hazardous Air Pollutant 

Emissions,” which is available from the rulemaking docket (see

ADDRESSES section). 

A. Applicability

Comment: Numerous commenters expressed concern over EPA’s 

decision to not distinguish between rural and urban engines at 

area sources in the proposed rule. Several commenters requested 

that EPA reevaluate its congressional authority to regulate area 

HAP sources in rural areas. The commenters believed that the 

proposal is inconsistent with 42 U.S.C. 7412(n)(4)(B) [CAA 

section 112(n)(4)(B)]. Commenters requested clarification of 

EPA’s rationale to regulate low levels of emissions from engines 

at oil and gas production facilities outside metropolitan areas, 

contending that EPA has applied this rule more broadly than the 

Congressional intent of the CAA, and requested that EPA 

reevaluate this issue of whether EPA can regulate rural area 

sources in light of the 42 U.S.C. 7412(n)(4)(B) language. 

Commenters stated that EPA has based this rulemaking for 

area sources on sections of the CAA and its Urban Air Toxics 

Strategy that are intended to remove threats to public health in 

urban areas. The commenters do not believe that the remote RICE 

at area sources in the oil and gas industry threaten public 

health in urban areas. Several commenters noted that the NESHAP 

for glycol gas dehydrators (40 CFR part 63, subpart HH) takes 
49 

into account the location of area sources and does not apply the 

specific requirements of the rule to rural area sources. The 

commenters believe that the same approach should be used for the 

RICE rule, i.e., engines that are not located in or near 

populated areas should be exempt or subject to an alternative 

set of requirements so as not to force expensive requirements on 

remote engines that have no impact on public health.

One commenter on behalf of the agricultural industry 

expressed that the operational area of these engines has not 

been studied to evaluate the environmental benefit obtained in 

congested areas as compared to open agricultural locations. 

This commenter opined that there should be some measure of 

variable compliance provided in relation to the area of 

operation of these engines.

Response: EPA is finalizing its proposal to regulate 

existing stationary CI engines located at area sources on a 

nationwide basis. EPA has not made a final determination with 

regard to existing SI engines at area sources, and will do so in 

the later rule finalizing regulations for SI engines. EPA 

believes that the CAA provides the Agency with the authority to 

regulate area sources nationwide. Section 112(k)(1) of the CAA 

states that “It is the purpose of this subsection to achieve a 

substantial reduction in emissions of hazardous air pollutants 

from area sources and an equivalent reduction in the public 
50 

health risks associated with such sources including a reduction 

of not less than 75 per centum in the incidence of cancer 

attributable to emissions from such sources.” Consistent with 

this expressed purpose of section 112(k) of the CAA to reduce 

both emissions and risks, CAA section 112(k)(3)(i) requires that 

EPA list not less than 30 HAP that, as a result of emissions 

from area sources, present the greatest threat to public health 

in the largest number of urban areas. Sections 112(c)(3) and 

(k)(3)(ii) of the CAA require that EPA list area source 

categories that represent not less than 90 percent of the area 

source emissions of each of the listed HAP. Section 112(c) of 

the CAA requires that EPA issue standards for listed categories 

under CAA section 112(d). These relevant statutory provisions 

authorize EPA to regulate listed area source engines and not 

just engines located in urban areas. EPA believes that sections 

112(c) and 112(k) of the CAA do not prohibit issuing area source 

rules of national applicability. EPA also disagrees with the 

statement that the proposal was inconsistent with section 

112(n)(4)(B) of the CAA. The term “associated equipment” was 

defined for the purposes of subpart ZZZZ in the first RICE MACT 

rule not to include stationary RICE. EPA has not revisited that 

issue in this rule and the commenters have not provided 

sufficient reason to revisit that issue. 
51 

EPA does not believe that existing stationary CI engines 

are more prevalent in rural areas than in urban areas. Indeed, 

EPA estimates that only 17 percent of stationary CI area source 

engines subject to the rule are located in rural areas, using 

the definitions used in the Urban Air Toxics Strategy. Given 

the requirement to regulate all engines in the source category 

in urban areas, we do not believe requiring regulation on a 

national basis is inappropriate. 

The majority of stationary CI engines are used for 

emergency purposes. EPA has estimated that 80 percent of 

stationary CI engines are emergency engines and EPA has taken 

steps in the final rule to reduce the burden on owners and 

operators of these engines. All emergency CI engines located at 

area sources of HAP emissions are subject only to management 

practices under the final rule. EPA has also determined that 

existing emergency engines located at residential, 

institutional, and commercial facilities that are area sources 

of HAP emissions were not included in the original Urban Air 

Toxics Strategy inventory and therefore are not included in the 

source category listing. In the final rule, EPA has specified 

that those engines are not subject to subpart ZZZZ. In 

addition, existing non-emergency CI engines less than or equal 

to 300 HP that are located at area sources of HAP emissions are 

also only subject to management practices. EPA believes that 
52 

requiring management practices instead of specific emission 

limitations and/or control efficiency requirements on the 

majority of existing stationary CI engines at area sources 

alleviates concerns regarding costly and burdensome requirements 

for rural sources. 

For existing stationary non-emergency CI engines greater 

than 300 HP, EPA determined that GACT was the use of oxidation 

catalyst control. The commenters did not provide a reason that 

GACT would be different for non-emergency stationary CI engines 

located in rural areas. In determining GACT, EPA can consider 

factors such as availability and feasibility of control 

technologies and management practices, as well as costs and 

economic impacts. These factors are not different for existing 

stationary non-emergency CI engines in urban versus rural areas. 

For example, the availability of oxidation catalysts would be 

the same for urban and rural engines, and if an engine was in a 

rural location, that would not preclude an owner from being able 

to install aftertreatment controls. For the final rule, EPA 

estimated the capital cost of retrofitting an existing 

stationary non-emergency CI engine to around $7,000 for a 300 HP 

engine. Annual costs of operating and maintaining the control 

device are estimated to be approximately $2,000 per year for the 

same engine. These costs would not be prohibitive for any 

engines and either rural or urban areas and are expected to be 
53 

the same no matter the location. Furthermore, the controls that 

are expected to be used on non-emergency engines above 300 HP 

will have the co-benefit of PM reductions. PM emissions can 

travel tens or hundreds of miles from their source, so emissions 

from diesel engines in rural areas can impact urban populations. 

There is also no reason to distinguish between the rural and 

urban area source engines that are subject to management 

practices. There is nothing limiting owners and operators of 

existing stationary CI engines located in rural areas from 

following the management practices specified in the final rule. 

In response to requests that agricultural stationary 

engines should be treated differently from other engines and 

should be allowed special provisions, EPA is of the 

understanding that the majority of stationary engines used for 

agricultural purposes are below 300 HP. Several commenters 

representing agricultural interests have made the statement to 

EPA that most of their engines are below 300 HP. As previously 

discussed in this response, EPA is finalizing management 

practices for area source engines less than or equal to 300 HP. 

Therefore, it is not expected that many stationary agricultural 

engines will be required to put on controls. Agricultural 

engines less than or equal to 300 HP at rural and urban area 

sources would be required to follow the management practices 
54 

specified in the final rule. Management practices will ensure 

that emissions are reduced and engines are properly operated. 

Consistent with the proposal and for the reasons discussed, 

EPA is finalizing national requirements for existing stationary 

CI engines without a distinction between urban and non-urban 

areas. 

Comment: Five commenters expressed that EPA’s proposal 

would have a significant impact to the State of Alaska, 

especially with respect to power generation in their rural 

communities. They explained that Alaska has unique regional 

circumstances whereby regulating diesel engine emissions in 

rural Alaska in the same manner as other engines nationwide 

could have unintended negative consequences. The commenters 

were concerned about the extension of section 112(k) of the CAA 

requirements to rural sources, expressing that the purpose of 

CAA section 112(k) is to address urban issues. The commenters 

opined that the scale of HAP emissions in rural areas of Alaska 

is different and should be addressed in a way that is 

appropriate to the rural conditions that exist there. The 

commenters expressed that, historically, EPA has recognized the 

unique aspects of rural Alaska’s diesel distribution system and 

diesel engine use and has allowed Alaska some flexibility (e.g., 

under the CI NSPS). The commenters requested that EPA assess 
55 

and consider rural Alaska’s situation and allow for flexibility 

to address the challenges associated with the proposed rule. 

Response: EPA agrees with the commenters that stationary 

CI area source engines located in remote areas of Alaska have 

special challenges that should be taken into consideration. As 

the commenters noted, over 180 rural communities in Alaska that 

are not accessible by the Federal Aid Highway System rely on 

stationary diesel engines and fuel for electricity. They are 

scattered over long distances in remote areas and are not 

connected to population centers by road or power grid. They are 

located in the most severe arctic environments in the United 

States. Transportation of diesel fuel to these areas is 

dependent on weather and communities typically pay some of the 

highest prices for fuel in the United States. Stationary 

engines located in rural areas of Alaska have different fuel 

storage and use logistics and higher operating and compliance 

costs. Many of these communities are accessible only by plane. 

In light of the comments, we believe it is appropriate to treat 

engines located at area sources in areas of Alaska that are not 

accessible by the Federal Aid Highway System as a separate 

subcategory. We re-evaluated GACT for the subcategory of 

stationary engines located at area sources of HAP that are in an 

area of Alaska that is not accessible by the Federal Aid Highway 

System. For these engines, we determined that GACT is the same 
56 

management practices as those required for non-emergency CI RICE 

less than or equal to 300 HP located at area sources. For more 

discussion of this issue, refer to the memo entitled “MACT Floor 

Determination for Existing Stationary Non-Emergency CI RICE Less 

Than 100 HP and Existing Stationary Emergency CI RICE Located at 

Major Sources and GACT for Existing Stationary CI RICE Located 

at Area Sources.” 

B. Final Emission Requirements

Comment: Several commenters expressed opposition to EPA’s 

proposal to have emission standards apply to small engines at 

major sources. Three commenters said that EPA should not 

finalize emission limits for engines less than 100 HP. One 

commenter argued that stationary engines that are less than 100 

HP should be exempted from numerical HAP emission standards. In 

the commenter’s opinion, it is not cost effective to install 

add-on controls on small engines or to purchase a new engine. 

According to the commenter, the majority of engines in this size 

range are operated for intermittent household or other 

infrequent use and emissions are naturally limited, the 

commenter said, and low emissions do not justify the costs 

associated with requiring a numerical HAP limit. One commenter 

does not believe that measurement is economically practicable 

for a small unit as the cost of testing will likely exceed the 
57 

value of the engine itself. The commenter urged EPA to exclude 

small sources from the category. 

 Response: EPA has reanalyzed its proposed standards based 

on the information and data presented and EPA concludes that it 

is not feasible within the context of this rulemaking to 

prescribe emission limitations for existing stationary CI 

engines smaller than 100 HP located at major sources, because 

the measurement of emissions from these engines is not 

practicable due to technological and economic limitations. In 

order to measure the emissions from these engines on a ppmvd at 

15 percent O2 basis, the following test methods are required: 

EPA Method 1 or 1A for selection of sampling ports; EPA Method 

3, 3A, or 3B for determining the O2 concentration; EPA Method 4 

for measuring the moisture content, and EPA Method 10 or ASTM 

D6522-00 (2005) for measuring the CO concentration. These test 

methods require the sample point to be a certain distance 

between the engine and the exhaust. Because engines below 100 

HP often have exhaust pipes with very small diameters and 

lengths, stack testing using these methods could require a 

modification or extension of the exhaust pipe to accomplish the 

test. The cost to do the testing ranges from approximately 

$1,000-$5,000 depending on the method used. Generally, 100 HP 

engines cost around $5,000-$7,000 dollars and 50 HP engines cost 

approximately $4,000-$5,000, so the cost of performance testing 
58 

could approach the cost of the engine itself. Given the cost of 

the testing itself, the physical adjustments necessary to 

accomplish the test, and the particular circumstances pertaining 

to stationary engines below 100 HP, we believe that the 

application of measurement methodology to this class of engines 

is not practicable due to technological and economic 

limitations. Therefore, EPA is promulgating work practice 

standards for these engines. Additional detail regarding this 

analysis can be found in the memorandum entitled “MACT Floor 

Determination for Existing Stationary Non-Emergency CI RICE Less 

Than 100 HP and Existing Stationary Emergency CI RICE Located at 

Major Sources and GACT for Existing Stationary CI RICE Located 

at Area Sources.” 

Comment: One commenter stated that the use of CO as a 

surrogate for HAP emissions from stationary diesel engines is 

flawed and does not meet the D.C. Courts three part test for 

reasonableness. According to the commenter, the D.C. Court 

surrogate three part test requires EPA to demonstrate each of 

the following: 1) HAP from the source must be “invariantly 

present” in the surrogate; 2) control technology that reduces 

the surrogate must “indiscriminately capture” HAP from the 

source; and 3) control of the surrogate is the only means to 

control HAP from the source. The commenter pointed out that EPA 

admitted that CO may not be an adequate surrogate for metallic 
59 

HAP emissions in the current proposal. The commenter argued 

that oxidation catalyst is only capable of 30 percent reduction 

of PM, thus allowing 70 percent of the PM, including metallic 

and semi-volatile HAP to be emitted to the atmosphere. In 

addition, the commenter pointed out that technologies that 

control CO are not the only means by which a source can achieve 

reductions in HAP emitted from stationary diesel engines. The 

commenter believes that based on the D.C. Court’s three tests, 

final standards are not appropriate, and recommended that EPA 

adopt standards based on PM rather than CO reductions. 

Response: EPA believes that CO emissions are an 

appropriate surrogate for HAP emissions for stationary CI 

engines. EPA has demonstrated the relationship between CO 

emissions and HAP emissions in previous rulemakings for 

stationary engines. EPA does not have any data to support a 

relationship between PM emissions and HAP emissions for 

stationary CI engines, nor did the commenter provide any data to 

support such a relationship for this source category. It is 

clear that there are methods for reducing PM emissions, like 

reducing sulfur from fuel, that may not lead to a reduction in 

HAP. In addition, it is not clear that reductions in PM would 

reduce emissions of all HAP emitted from stationary engines, 

particularly emissions of formaldehyde, acetaldehyde, etc., that 

represent the vast majority of the HAP emissions from this 
60 

source category. Therefore, for this particular source 

category, use of PM as a surrogate for HAP is not appropriate. 

The commenter also did not provide any data from testing of 

stationary CI engines to show that CO is not a good surrogate 

for metallic HAP. CO is also a better surrogate for HAP emitted 

from stationary CI engines than PM because PM is more difficult 

and expensive to measure than CO for this source category. For 

semi-volatile HAP, the testing conducted by EPA at Colorado 

State University showed that an oxidation catalyst reduced PAH 

emissions by greater than 90 percent for most of the PAH that 

were tested, and that CO level reductions correlated with level 

reductions in such HAP. 

In addition, as discussed above, EPA is taking an 

additional action pursuant to its authority under section 

112(d)(2)(B) and (C) for further control of metallic HAP. EPA 

determined that the most effective and achievable method for of 

controlling metallic HAP emissions from existing stationary CI 

engines is through the use of crankcase emission control 

systems. Combustion gases and oil mist that are vented from the 

engine crankcase are a substantial source of any metallic HAP 

emissions from stationary CI engines. EPA is promulgating a 

further standard under section 112(d)(2)(B) and (C) that 

requires stationary non-emergency diesel engines greater than 

300 HP to install either an open or closed crankcase filtration 
61 

emission control system if the engine is not already equipped 

with one. The open crankcase filtration emission control system 

reduces emissions from the crankcase by filtering the exhaust 

stream to remove oil mist, particulates, and metals. In the 

case of the closed system, crankcase emissions are collected and 

filtered and those that remain in a gaseous state are routed to 

the intake manifold for burning. We believe this requirement 

will reduce metallic HAP from the stationary engine emissions. 

Comment: Multiple commenters were concerned with how EPA 

set the MACT floor for the proposed rule. Several commenters 

said that EPA has not considered variability in setting the MACT 

floor for the proposed rule. A commenter cited the recent Brick 

MACT ruling which indicated that “floors may legitimately 

account for variability [in the best performing sources that are 

the MACT floor basis] because “each [source] must meet the 

[specified] standard every day and under all operating 

conditions.” The commenters stated EPA’s data set is not 

sufficient in covering variability. One commenter noted that 

the Courts have been critical of EPA’s process for setting 

minimum allowable emission limits. The commenter stated that 

EPA set the emission limits by averaging the best 12 percent of 

all performance tests for each subcategory, but did not consider 

operational variations of the units. The commenter recommended 

that EPA set emission limits at the emissions level that is 
62 

actually achieved under the worst reasonably foreseeable 

circumstances for the best performing 12 percent as allowed by 

the Courts in the Cement Kiln MACT and Brick Kiln MACT 

decisions. 

Multiple commenters suggested that EPA should consider a 

scenario under which lower temperatures and reduced catalyst 

efficiencies may occur due to reduced engine speed or load, 

resulting in lower temperatures and consider an alternative work 

practice under section 112(h) of the CAA for the situation. Two 

commenters noted that the emission standards in the proposed 

rule apply at all times, but that there is no data or 

information in the rulemaking docket that supports the proposed 

limits at low loads or at operating conditions other than high 

load. The commenters expressed that EPA should provide data and 

analysis that supports requiring emission limits to be met at 

all times. Also, for compliance at all times, the commenter 

asked what averaging times apply. 

Response: EPA agrees that emissions variability should be 

better analyzed and has included a revised approach to 

variability in the MACT floor analysis. The final emission 

standards are based on test data collected from stationary 

engines produced by different engine manufacturers, operating at 

various loads and other conditions, and located in various types 

of service and locations. The engines range in size from 160 HP 
63 

to 3,570 HP. The data includes engines operating at loads from 

25-100 percent. To the extent commenters believed further data 

would have beneficial to EPA, EPA must make its determinations 

based on the information available to it. EPA asked for further 

data, and EPA did receive further data following the proposal, 

which led to changes in the final regulations. For engines 

operating at reduced speed or loads resulting in a reduced 

exhaust temperature, EPA believes that numerical emission 

requirements are still appropriate and there is no justification 

to only require work practice standards during these situations. 

We do not believe that the provisions of section 112(h) of the 

CAA are met (except as discussed elsewhere with regard to 

periods of start-up, emergency engines, and engines below 100 

HP) because testing is not economically and technologically 

impractical and the emissions can be readily routed through a 

conveyance for purposes of emission testing. EPA believes that 

the final emission standards will be achievable at all times 

covered by the standards and will reflect the numerous engine 

models and operating scenarios that can be expected from 

stationary engines. 

 Regarding the comment asking about the averaging times that 

apply, EPA has clarified in the final rule that the emission 

standards are based on the average of three one-hour runs. 
64 

Comment: Several commenters expressed concern with the 

proposed limits for emergency engines at both area and major 

sources. Numerous commenters stated that EPA should adopt 

management practices for emergency engines at area sources and 

not require emission limits from these engines. Commenters 

stated that emergency engines need special consideration, due to 

minimal operation, and the commenters said that EPA should apply 

section 112(h) of the CAA for emergency engines at major sources 

because of this limited operation. Several commenters 

recommended that emergency engines be subject to only work 

practice standards that limit the number of hours allowed for 

operation during non-emergency events. 

Several commenters recommended that EPA require management 

practices rather than a numerical emission limit for emergency 

diesel generators greater than 500 HP at area sources. The 

commenters suggested that such management practices could 

replace the existing proposed emission standard requirements for 

emergency CI engines greater than 500 HP. The commenters stated 

that the proposed rule and related docket indicates that CI 

emergency diesel engines can achieve a 40 ppmvd CO emission 

standard for both normal operations and startup or malfunction 

periods without add-on technology, which the commenters did not 

believe was correct. The commenters said the proposed 

rulemaking does not provide any basis for the proposed standards 
65 

for emergency engines of this size range, and the GACT 

determination has not been properly established for these 

engines. In particular, according to the commenters, subsection 

1 of section IV.B. of the proposed rule, which is cited in 

subsection 2 as the basis for the area source standards for 

large CI engines, does not appear to include any discussion of 

emission controls for emergency CI engines greater than 500 HP. 

In the absence of such justification, the commenters state that 

the MACT floor for these large engines is no controls. The 

commenter acknowledged that such a no control argument may not 

be acceptable under the MACT because of the Brick MACT court 

case, but the commenters stated that there is no such limitation 

in making GACT determinations. The commenter was concerned that 

establishing an emission standard for large emergency CI engines 

would establish requirements for the installation of add-on 

controls for some, if not most of the sources in that category. 

EPA needs to conduct a regulatory analysis and assessment of the 

costs of these controls. The commenter gave an example of the 

impact of an emission limit and the impact of installing 

controls on one of his units. The commenter concluded that 

because of the unit’s limited operation, an oxidation catalyst 

control will have limited, if any, control effectiveness in 

actual use. 
66 

 The commenters said that despite EPA’s claims that the 

agency is not requiring performance tests of emergency engines, 

major sources with existing emergency engines appear to have an 

implicit testing requirement to demonstrate that they comply 

with concentration limits. Such testing could significantly 

increase the time the typical emergency engine would be used in 

year and impose additional environmental impact and costs. The 

commenters said EPA needs to resolve the conflict between the 

preamble and the regulatory language and replace the emission 

limits for emergency engines with work practices. The 

commenters raised similar concerns about the apparent 

requirement for performance testing of emergency RICE due to 

ambiguous rule language and said it should be clarified to 

explicitly state that such testing is not required. The 

commenter said the rule would require not only initial 

performance testing, but testing every 3 years. Because engine 

operation for performance testing would likely exceed typical 

operation for operational testing and maintenance, these testing 

requirements would result in increased operation of the engine 

with a corresponding significant increase in operating costs and 

emissions of other pollutants such as NOx. The commenters said 

emergency engines are used only during emergencies, other than 

short (less than one-half hour) weekly tests to assure the 

engines will perform. According to the commenter, performance 
67 

tests (initial or every 3 years) consisting of three 1-hour runs 

typically cost about $10,000 each and are not justified for 

limited use engines, the tests alone would add substantially to 

the fuel use of these engines are result in additional and 

unnecessary emissions and work practice standards under section 

112(h) are more appropriate due to “technological and economic 

limitations.” 

 Response: EPA reviewed the information submitted by the 

commenters and determined that it would be appropriate to 

require management practices for all emergency stationary CI 

engines at area sources. Because these engines are typically 

used only a few number of hours per year, the costs of emission 

control and the costs of emission testing are not warranted when 

compared to the emission reductions that would be achieved. The 

proposed numeric emission levels are not GACT for emergency 

engines at area sources. Such engines rarely if ever use the 

type of emission controls that might have been necessary for 

many engines to meet the numeric standard, and such engines are 

rarely if ever subjected to emissions testing. Therefore, EPA 

determined that GACT for all stationary emergency engines at 

area sources is the use of management practices. 

 EPA also analyzed the types of engines that were included 

in the area source category listing for stationary RICE. As a 

result of this analysis, EPA determined that emissions from 
68 

existing stationary emergency engines located at residential, 

commercial, and institutional facilities that are area sources 

of HAP were not included in the 1990 baseline emissions 

inventory that was used as the basis for the listing of source 

categories needed to ensure that 90 percent of area source 

emissions are regulated. Existing stationary emergency engines 

located at residential, commercial, and institutional facilities 

that are area sources are therefore not subject to this 

regulation. 

 For stationary emergency engines at major sources, EPA 

determined that it is not feasible to prescribe or enforce an 

emission standard because the application of measurement 

methodology to this class of engines is impracticable due to 

technological and economic limitations. A more detailed 

discussion of this determination can be found in the memorandum 

entitled “MACT Floor Determination for Existing Stationary NonEmergency CI RICE Less Than 100 HP and Existing Stationary 

Emergency CI RICE Located at Major Sources and GACT for Existing 

Stationary CI RICE Located at Area Sources.” EPA determined 

that it is impracticable to test stationary CI emergency engines 

using the test procedures specified in subpart ZZZZ because 

using these procedures would increase the required number of 

hours of operation of the engine beyond the routinely scheduled 

reliability testing and maintenance operation, thereby 
69 

increasing emissions. While emergency engines have periods of 

operation for scheduled maintenance and reliability testing, 

those periods are usually several hours shorter than the number 

of hours that would be required to run the necessary emissions 

tests under subpart ZZZZ. CARB conducted a survey of stationary 

emergency diesel engines in 20022

 to determine the average number 

of hours that stationary emergency diesel engines operate. The 

average hours of operation for maintenance and testing were 22 

hours per year, which is less than two hours per month. For the 

engines that CARB surveyed, 86 percent operated less than 30 

hours/year for testing and maintenance. Thirty percent operated 

less than 10 hours/year. National Fire Protection Association 

(NFPA) codes require that stationary diesel engines that are 

used for emergency purposes are run 30 minutes per week (27 

hours per year) for maintenance and testing purposes. It is 

impracticable to test emergency stationary engines as a result 

of emergency operation because emergencies are unplanned events 

and implementation of the test procedures specified in subpart 

ZZZZ require advance planning before tests are conducted. In an 

emergency, the owner/operator does not have the advance planning 

time necessary to implement subpart ZZZZ. It is also 

 

2

 California Air Resources Board Staff Report: Initial Statement 

of Reasons for Proposed Rulemaking. Airborne Toxic Control 

Measure for Stationary Compression Ignition Engines. Stationary 

Source Division, Emissions Assessment Branch. September 2003. 
70 

impracticable to test stationary CI emergency engines at major 

sources because of the large population of these engines. EPA 

estimates that there are over 200,000 existing stationary CI 

engines from 100-500 HP at major sources that are subject to 

this rulemaking. There are only approximately 300-400 testing 

firms and these stationary engines are not the only sources that 

are required to be tested, so if testing were required for these 

engines, it would take many years to test all of these engines. 

The cost for testing all of these engines would also be 

approximately $200 million, which would be unreasonable. 

 EPA expects that these changes from the proposed rule 

address the concerns expressed by the commenters about the 

requirements for stationary emergency CI engines. Regarding the 

comments pertaining to performance testing for emergency 

engines, EPA did not intend for the rule to require performance 

testing for emergency engines. The final rule does not contain 

any performance testing requirements for emergency engines. 

 Comment: One commenter recommended that the standard 

require CDPF or a combination of oxidation catalysts and CDPF 

for new or existing non-emergency diesel RICE. The commenter 

stated that EPA’s proposal calls for oxidation catalysts on nonemergency CI engines, which EPA reports will result in a 90 

percent reduction in CO and 30 percent reduction in PM, whereas 
71 

CDPF would result in greater reductions in PM (90 percent 

reductions or greater). 

Another commenter reported that it had conducted risk 

assessment evaluations for diesel particulate emissions from 

non-emergency diesel engines and found that the diesel 

particulate emissions from non-emergency diesel engines and 

found that the diesel particulate emissions often create a 

significant cancer risk even when there is a 30 percent PM 

reduction. The commenter recommended that EPA base standards on 

CDPF or a combination of oxidation catalyst and CDPF, for 

existing and new non-emergency diesel engines. 

 Response: The standards that EPA proposed and that EPA is 

finalizing do not require a particular control technology. For 

the proposed rule, EPA’s beyond-the-floor analysis resulted in 

standards that were based on the use of oxidation catalyst 

control for stationary non-emergency diesel engines above 300 

HP; EPA has made the same determination for the beyond-the-floor 

standards in the final rule. EPA determined that the MACT 

standards should be based on oxidation catalyst rather than CDPF 

because we do not have any data that shows that CDPFs get 

greater reductions of HAP than oxidation catalysts on stationary 

engines, and CDPFs are approximately four times as costly as 
72 

oxidation catalysts.3 EPA also has concerns regarding the 

technical feasibility of CDPFs for existing stationary diesel 

engines. Many existing diesel engines are not electronically 

controlled, and PM emissions from older engines are often too 

high for efficient operation of a CDPF. Further, engine exhaust 

temperatures are often not high enough for regeneration of the 

CDPF filter substrate. EPA notes that owners and operators are 

free to choose whichever control technology, which could be 

oxidation catalyst or CDPF, as long as they meet the final 

standards. EPA is not addressing new diesel engines in this 

rulemaking. 

Comment: A few commenters were concerned about 

requirements that might apply to engines that startup turbines. 

Four commenters suggested that RICE used to startup combustion 

turbines be exempt from the proposed rule, or deemed to fall 

under the “emergency” definition in 40 CFR §63.6675. One 

commenter explained that turbine RICE only run for a few minutes 

to get the unit started and the total fuel consumption is not 

significant. One commenter was concerned that the short runtime during each operation may not be long enough to get the 

filter up to its design temperature for achievement of its 

 

3

 California Air Resources Board Staff Report: Initial Statement 

of Reasons for Proposed Rulemaking. Airborne Toxic Control 

Measure for Stationary Compression Ignition Engines. Stationary 

Source Division, Emissions Assessment Branch. September 2003. 
73 

removal efficiency (and note that EPA discusses it in the 

preamble) or that a filter may require additional run time for 

regeneration. The commenter further noted that the additional 

run-time required by the 3 year testing requirement could 

outstrip the run-time needed to support these combustion turbine 

peaking unit starting devices just for compliance with the RICE 

rule. The commenter noted that increased consumption of fuel 

for rule compliance would be wasting the natural resource and 

adding emissions for no measurable reduction being gained by the 

rule. Two commenters noted that every major power plant in the 

United States is required to have black start capability, which 

typically involves a small combustion turbine equipped with a 

diesel engine used for startup of the turbine. According to the 

commenter, the diesel starting engine, rated less than 500 HP, 

generally operates less than 10 minutes per combustion turbine 

start. The commenter indicated that the majority of black start 

units only operate during emergencies or unusually high demand 

days, and that a review of the commenter’s company’s operating 

data determined that seven black start units in the system 

averaged 32 starts per year (which equates to less than 6 hours 

of operation per year, although some limited additional 

operation may occur as a result of routine maintenance and 

readiness testing). 
74 

 Response: In the final rule EPA has required that 

stationary engines used to startup combustion turbines meet work 

practice standards. EPA finds that the short time of operation 

for these engines (10-15 minutes per start) makes application of 

measurement methodology for these engines using the required 

procedures, which require continuous hours of operation, 

impracticable. Requiring numerical emission standards for these 

engines would actually require substantially longer operation 

than would occur normally in use, leading to greater emissions 

and greater costs. EPA also agrees with the commenters that it 

would not be appropriate to set emission limits that are based 

on the use of aftertreatment control for the subcategory of 

stationary CI engines that are used to startup combustion 

turbines. Oxidation catalyst control would not be effective for 

these engines due to their short time of operation (10-15 

minutes per start). 

C. Management Practices

Comment: Several commenters did not agree with the 

specific management practices that EPA has proposed in the rule 

for area sources or recommended different maintenance practices. 

According to the commenters, the maintenance frequency in the 

proposed rule exceeds current practices or is not supported in 

the proposed rule. Several commenters agreed that management 

practices are appropriate for the proper operation of the 
75 

engines and is a reasonable means to reduce HAP emissions, 

however, did not agree with the specific maintenance practices 

proposed by EPA. Numerous commenters recommended that EPA allow 

owners/operators to follow engine manufacturers’ recommended 

practices or the owners/operators own site-specific maintenance 

plan. 

One commenter pointed out that operators have a direct 

interest in maintaining engine oil, hoses, and belts, so the 

engine runs reliably, but the appropriate frequency for these 

maintenance practices are specific to engine design and are not 

“one size fits all.” Ten commenters recommended that EPA revise 

fixed maintenance (one-size-fits-all) requirements to 

maintenance plans. The commenters stated that, while fixed 

maintenance intervals work well for new mass produced engines 

similar to those in automobiles, they are inappropriate for the 

wide variety of existing engines used in the oil and gas, 

agriculture, and power generation industries across the nation. 

The commenters pointed out that EPA allows the use of operatordefined maintenance plans that are “consistent with good air 

pollution control practice for minimizing emissions” to be used 

in other portions of this same rule, and asserted that EPA 

should allow the use of operator-defined maintenance plans to 

greatly reduce cost and allow operators to optimize maintenance 

for each type of engine. 
76 

 One of these commenters added that current industry engine 

maintenance programs are driven by tried-and-true practices and 

since these practices effectively keep the engines running, they 

allow the products of the members of the commenter’s 

organization to go to market. The commenter stated that 

additional, burdensome, frequent, and time-consuming maintenance 

requirements will cause the members of the commenter’s 

organization to more-frequently shut down engines and thus shut 

down production. 

Two commenters said that if EPA keeps the management 

practices as proposed, the frequencies associated with 

conducting engine maintenance should be revised to be 

commensurate with today’s practices. The commenter believes the 

maintenance practices, as proposed, are significantly burdensome 

and lack basis. According to the commenters, EPA should replace 

the maintenance hour intervals with company recommended 

performance-based maintenance practices to be documented in an 

operator-defined maintenance plan consistent with requirements 

in 40 CFR part 60, subpart JJJJ. 

One commenter stated that most of the engine manufacturers 

for the engines in the oil and gas industry recommend oil 

changes on a monthly schedule. The commenter also indicated 

that it is common practice to periodically sample and test the 

engine oil to see if the oil properties are sufficient to extend 
77 

this time period between oil changes. According to the 

commenter, this testing has shown in many cases that the oil 

change interval can be extended without any detrimental effects 

on the engine, which allows industry to maximize efficiencies, 

minimize oil usage, reduce waste, and streamline operations with 

no negative impacts to the engine or emissions. 

One commenter expressed that inspection of hoses and belts 

has no impact on HAP emissions. The commenter expressed that, 

generally, it agreed that performing maintenance on engines will 

help to reduce HAP emissions, but that while inspecting belts 

and hoses is an important part of general engine maintenance 

(and most sources likely conduct regular inspections of their 

engines), such inspections have no effect on emissions and 

should be removed from the proposed rule. 

Response: EPA proposed to require specific management 

practices for certain engines, primarily for smaller existing 

stationary engines at area sources where EPA thought that add-on 

controls were not GACT. EPA indicated at proposal that the 

management practices specified in the proposal reflected GACT 

and that such practices would provide a reasonable level of 

control, while at the same time ensuring that the burden on 

particularly small businesses and individual owners and 

operators would be minimized. EPA asked for comment on the 
78 

proposed management practices and received comments on the 

proposal from industry. 

EPA agrees with the commenters that it is difficult to 

adopt a set of management practices that are appropriate for all 

types of stationary engines. Regardless, EPA must promulgate 

emission standards pursuant to section 112(d)(5) for all engines 

at area sources covered by the final rule. EPA still believes 

that a management practice approach reflects GACT for emergency 

engines and smaller engines at area sources. These management 

practices represent what is generally available among such 

engines to reduce HAP, and the practices will ensure that 

emissions are minimized and engines are properly operated. EPA 

does not agree with the commenters that it would be appropriate 

to simply specify that owners and operators follow the 

manufacturer’s recommended maintenance practices for the engine. 

EPA cannot delegate to manufacturers the final decision 

regarding the proper management practices required by section 

112(d). To address the comments that there may be special and 

unique operating situations where the management practices in 

the rule may not be appropriate, for example engines using a 

synthetic lubricant, EPA noteshas included a provision in the 

final rule that allows owners/operators mayto work with state 

permitting authorities pursuant to 40 CFR subpart E (‘‘Approval 

of State Programs and Delegation of Federal Authorities’’) for 
79 

approval of alternative management practices for their engines. 

Subpart E implements section 112(l) of the CAA, which authorizes 

EPA to approve alternative state/local/tribal HAP standards or 

programs when such requirements are demonstrated to be no less 

stringent than EPA promulgated standards. 

 The management practices EPA proposed for stationary 

engines greater than 50 HP included changing the oil and filter 

every 500 hours, replacing the spark plugs every 1,000 hours, 

and inspecting all hoses and belts every 500 hours and replacing 

as necessary. For engines less than 50 HP, EPA proposed to 

require that these engines change the oil and filter every 200 

hours, replace spark plugs every 500 hours, and inspect all 

hoses and belts every 500 hours and replace as necessary. 

 EPA agrees that there is a wide range of recommended 

maintenance procedures, but EPA must promulgate specific 

requirements pursuant to section 112(d) for this source 

category. Based on the different suggested maintenance 

recommendations EPA has reviewed, maintenance requirements 

appear to vary depending on whether the engine is used for 

standby, intermittent, or continuous operation. Maintenance is 

also dependent on the engine application, design, and model. 

Taking into consideration the information received from 

commenters on the proposed maintenance practices for oil and 

filter changes and carefully reviewing engine manufacturer 
80 

recommended maintenance procedures, EPA has determined that for 

stationary non-emergency engines below 300 HP, GACT will require 

the oil and filter to be changed every 1,000 hours of operation 

or annually, whichever comes first, which reflects the 

management practices that are generally available. For 

stationary emergency engines, the final rule requires the oil 

and filter to be changed every 500 hours of operation or 

annually, whichever comes first. EPA notes that in the final 

rule it has clarified that spark plug changes are not required 

for stationary diesel engines since diesel engines do not use 

spark plugs. EPA also determined that it would be appropriate 

to include the option to use an oil analysis program in the 

final rule. 

EPA does not agree with the comments that inspecting belts 

and hoses has no impact on emissions. Ensuring that the engine 

is properly operated and maintained will help minimize the HAP 

emissions from the engine. Properly maintained belts and hoses 

allow the engine to operate at maximum efficiency. Hoses are 

generally used to move coolant through the engine to prevent the 

engine from overheating. Overheating of the engine can cause a 

malfunction in the combustion process, and may also burn the 

engine oil in the combustion chamber. Both of these conditions 

may increase pollutant emissions from the engine. Belts are 

commonly used for electrical generation and engine timing, and 
81 

if worn or broken can cause damage to the engine and increase 

emissions. Therefore, EPA has required management practices 

that reflect GACT and that, in EPA’s view, will ensure the 

proper operation and maintenance of the engine. 

D. Startup, Shutdown and Malfunction

Comment: Several commenters expressed serious concern over 

the proposed emission standards for periods of startup, 

shutdown, and malfunction (SSM). The commenters state that the 

U.S. Court of Appeals for the District Columbia Circuit vacated 

the SSM exemption in 40 CFR part 63, subpart A on December 19, 

2008, and the decision requires the Agency to implement 

standards that apply at all times, including during SSM periods. 

Numerous commenters thought the quick response to the December 

2008 Court decision on the SSM issue is premature and 

recommended that EPA wait for a final decision before 

incorporate elements from this case. Numerous commenters are of 

the opinion that EPA has not provided a technical basis for its 

establishment of SSM limits and that any SSM limits should be 

replaced with work practice standards and disagreed with the 

decision to include limits for SSM periods. In addition, 

several commenters said that emissions during SSM events cannot 

be measured and therefore cannot be confirmed and limits are not 

enforceable. One commenter recommended that EPA require a SSM 

plan similar to the SSM plan currently required under 40 CFR 
82 

part 63, subpart ZZZZ. The commenter also pointed out that 40 

CFR 63.6650(b) in the existing rule requires operators to 

operate and maintain their equipment in a manner consistent with 

good air pollution control practices at all times, including 

periods of SSM. The commenter believed that this requirement in 

conjunction with a SSM plan will achieve the same goals as the 

proposed rules in a much more cost effective and logical manner. 

Many commenters recommended that EPA consider other 

alternatives to implement during SSM periods, such as possibly 

requiring work practice standards, which the commenters believe 

is the most reasonable approach and is justified under the CAA. 

Commenters believed that work practices standards that minimize 

the emissions during of SSM periods is the most practical method 

of keeping HAP emissions from engines as low as possible. 

 Several commenters said that there is no method to 

determine compliance during SSM periods. The commenters said 

that it will be difficult or impossible to design a test program 

to describe emissions during SSM events, e.g., the commenter is 

not sure how a malfunction would be defined considering the 

unexpected and anomalous nature of the event. Therefore, 

emissions during these periods cannot be confirmed, the 

commenters said. Similarly, commenters believed that it is not 

reasonable to set numerical limits during startup because there 

are no available or repeatable test methods or procedures for 
83 

measuring emissions during startup or malfunction, plus there is 

no prescribed definition of what constitutes startup of an 

engine, which can vary significantly for a number of reasons 

such as engine and catalyst type, fuel, climatic conditions, 

application and load. 

One commenter said that there are no viable measurement 

methods available to measure CO, formaldehyde or VOC during 

transient operation and a review conducted by the commenter of 

Table 4 in the proposed rule shows the inconsistencies related 

to transient measurement acceptability with respect to stack gas 

moisture and flow rate, delays in the actual response of 

analyzers, issues in obtaining an accurate measurement during a 

transient test due to an axial diffusion function in long 

gaseous emissions sample lines, and field gaseous emission 

measurements require stack traverse as well for the emissions 

under measurement, per EPA Methodsmethods 7, 10, 25, etc., which 

eliminates the possibility of getting an accurate measurement 

during transient events such as a startup. 

One commenter claimed that issuance of numerical limits for 

SSM based on the emissions of the “best controlled sources prior 

to full warm up of the catalytic control” fails to consider 

emissions during malfunction of the engines themselves. The 

commenter asserts that while EPA appropriately determined that 

during a control device malfunction, the floor and standard 
84 

cannot be set assuming operation of the control device, EPA errs 

in limiting its analysis solely to operation of the controls 

since emissions can increase as a result of engine malfunctions 

as well. The commenter noted that its experience is consistent 

with EPA’s statements that emissions during an engine 

malfunction may increase due to the effects on exhaust 

temperatures and composition. The commenter concluded that 

emission limits would need to be based on the emissions level 

from the best performing sources without control while the 

engine is malfunctioning. One commenter added that it does not 

make sense to set any numerical standards during a malfunction 

of an engine because inherent in the concept of a malfunction is 

that emissions will be malfunctioning as well. It is also not 

logical to apply the concept of “best performing” malfunctioning 

engine, the commenter said. For these reasons, it is 

unreasonable for EPA to promulgate numerical emission limits for 

periods of malfunction, in the commenter’s opinion. Emission 

testing for malfunctions would be near impossible to conduct 

given the sporadic and unpredictable nature of the events, the 

commenter said. The commenter said that the nature of 

malfunctions means it is not feasible to predict or simulate 

emissions that occur during periods of malfunctions. The 

commenter asserted that with respect to engines, it is not 

technologically or economically feasible to apply measurement 
85 

methodology for the emissions during SSM periods and further, 

that it is unreasonable for the Agency in the face of the lack 

of accurate emission measurements to simply set the standard at 

the level for normal operations (e.g., for sources not using a 

control device). The commenter stated that this situation is 

precisely the circumstance in which Congress envisioned that a 

work practice standard would be established, and urged EPA to 

adopt a work practice standard applicable to malfunction and 

startup periods for engines consistent with section 112(h) of 

the CAA and not to apply the numerical limits for normal 

operations. 

 One commenter stated that EPA solicited comment on the 

level of specificity needed to define the periods of startup and 

malfunction. The commenter believes the responses differ based 

on whether the event is a startup or malfunction. The commenter 

noted that startup of an engine begins with the start of fuel 

flow to the engine and ends when the engine has achieved normal 

operating temperature and air to fuel flows as indicated by the 

manufacturers’ specifications, and while the initiation of a 

startup is predictable, its conclusion is not time-determined, 

but operationally-determined. The commenter noted where a 

catalyst is used to control emissions; startup does not end 

until the required catalyst bed temperature has been achieved, 

however, this may happen before the engine air and fuel flows 
86 

are normal and thus catalyst bed temperature is not the 

exclusive criterion that defines the end of the startup period. 

The commenter noted that the start of the malfunction should be 

defined as when the normal operation emission limit is exceeded 

and the end of the malfunction should be set as when the normal 

operation emission limit is restored or the engine is shutdown. 

The commenter noted that malfunctions often require shutdown to 

address, but such shutdowns can be delayed because immediate 

engine shutdown would cause other upsets. Therefore, the 

commenter believes it would not be reasonable to set any 

specific time limits on either startup or malfunction periods, 

because their duration can be a function of operational need. 

Similarly, one commenter disagreed that it would be appropriate 

to set a specific limit on the time allowed for startup because 

not all engines experience the same type of startup and 

malfunction. The length of startup will depend on many factors 

including engine type, size, fuel type and duty cycle, plus the 

frequency of required startups will also vary greatly among 

engines because some engines are only used for intermittent 

operation. 

Some commenters thought that limiting the engine startup 

time is a reasonable method to limit emissions. The commenter 

added that the most effective way to control emissions during 

startup for engines with catalysts is to limit the amount of 
87 

time it takes to warm up the exhaust to initialize the 

catalyzation process and startup time can be easily monitored. 

The commenter added that the time to be monitored at startup be 

defined as from the initial engine in-cylinder combustion, 

corresponding with continuous operation, up to the point that a 

defined catalyst inlet temperature is reached. The commenter 

also recommended that owners/operators be able to request 

additional startup time if necessary in special circumstances, 

e.g., in extremely cold climates or where sufficient load cannot 

be reached within 30 minutes. The commenters recommended a 

limit of one hour for startup and 30 minutes for shutdown. The 

rule should not include a time limit for malfunctions, as the 

length of time during which an engine will be out of compliance 

would depend on the type of malfunction, the commenters said. 

The commenters suggested that each affected source would be 

required to prepare a SSM plan, which would have to address 

appropriate actions and time limits for malfunctions. The 

commenter suggested that for engine startups, the work practice 

should require loading the engine to normal operating load as 

soon as practicable so that the catalytic controls are within 

operating range as soon as practicable 

 The commenters also objected to EPA’s proposed second 

option. The commenter said the data are apparently derived from 

the best controlled engines not using catalytic controls. The 
88 

commenter said that emissions data from steady-state operation 

of uncontrolled engines does not account for the cooler engine 

and fuel temperature conditions during startup. Nor does the 

second option properly account for malfunctions. 

One commenter proposed that EPA treat SSM emissions as de 

minimis, using the D.C. Circuit rationale in Alabama Power Co. 

v. Costle. The commenter noted that catalyst systems do not 

perform at low temperatures, and the SSM periods vary in 

duration and intensity, which can significantly impact actual 

emissions profiles. The commenter provided examples of why an 

assumption that SSM emissions are identical to normal stable 

operations emissions is erroneous and a gross oversimplification of unit operations. 

 Response: EPA received extensive comments on the proposed 

requirements applicable to existing stationary engines during 

SSM. Consistent with the recent Court decision that vacated the 

exemption in 40 C.F.R. 63.6(f)(1) and (h)(1) for SSM (Sierra 

Club v. EPA, 551 F.3d 1019), EPA has established standards in 

this rule that apply at all times.affecting existing stationary 

engines during startup and malfunction. The United States Court 

of Appeals for the District of Columbia Circuit vacated two 

provisions in EPA’s CAA Section 112 regulations governing the 

emissions of HAP during periods of SSM. Sierra Club v. EPA, 551 

F.3d 1019 (D.C. Cir. 2008). Specifically, the Court vacated the 
89 

exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), 

that are part of a regulation, commonly referred to as the 

“General Provisions Rule,” that EPA promulgated under section 

112 of the CAA. When incorporated into CAA Section 112(d) 

regulations for specific source categories, these two provisions 

exempt sources from the requirement to comply with the otherwise 

applicable CAA section 112(d) emission standard during periods 

of SSM. Consistent with the court’s holding that section 112 

requires continuous 112-compliant standards, EPA has established 

standards in this rule that apply at all times, where compliance 

is based on the average results of three one hour tests. EPA 

disagrees with those comments suggesting that EPA was premature 

in proposing standards during periods of startup, shutdown and 

malfunction. The United States Court of Appeals for the 

District of Columbia Circuit issued its opinion vacating the SSM 

exemption in 40 CFR 63.6(f)(1) and (h)(1) in December 2008, and 

we appropriately accounted for that decision in proposing the 

rule in FebruaryMarch 2009. EPA does not believe it is 

appropriatepremature to promulgate final rules that are 

inconsistent with the decision of the D.C. Circuit. 

EPA has determined that the emissions from stationary CI 

engines during startup are significantly different than the 

emissions during normal operation. During startup, incomplete 

combustion of the diesel fuel causes variations in the pollutant 
90 

concentrations and fluctuations in the flow rate of the exhaust 

gas. Incomplete combustion is due to cold areas of the cylinder 

walls that cause the temperature to be too low for efficient 

combustion. As the engine continues to operate, these cold 

regions begin to heat up and allow for more complete combustion 

of the diesel fuel and stabilization of the exhaust flow rate 

and pollutant concentrations. In addition, the engine 

experiences extreme transient conditions during startup, 

including variations in speed and load, poor atomization of the 

fuel injection, which leads to variable engine and engine 

exhaust temperatures, variable exhaust gas flow rates, and 

variable diluent pollutant concentration. Note for example the 

brief time spent at different load conditions as shown in Figure 

1 of the attachment to EMA’s letter dated February 17, 2009 

(EPA-HQ-OAR-2008-0708-0019), which illustrates the transient 

nature of the engine startup phase. Other factors that cause 

emissions to be higher during startup, including for engines 

that are not equipped with oxidation catalyst, are a higher 

propensity for engine misfire and poorer atomization of the fuel 

spray during startup. After-treatment technologies like 

oxidation catalysts and CDPFs must also reach a threshold 

temperature in order to reduce emissions effectively. In the 

February 17, 2009, EMA letter, EMA provided various graphs 

illustrating sample engine startup profiles and graphs 
91 

demonstrating the effect of engine exhaust temperature on 

catalyst efficiency. Figure 6 of the attachment to EMA’s letter 

(EPA-HQ-OAR-2008-0708-0019.1) shows how the CO efficiency is a 

function of the catalyst inlet temperature. and reaches 70 

percent conversion efficiency at roughly 250°C. As can be seen 

in Figure 1 of the attachment to EMA’s letter, reaching a 

catalyst inlet temperature of around 250°C may take several 

minutes. 

EPA has evaluated the criteria in section 112(h) and 

carefully considered and reviewed the comments on this issue. 

EPA has determined that it is not feasible to prescribe a 

numerical emission standard for stationary CI engines during 

periods of startup because the application of measurement 

methodology to these engines is not practicable due to the 

technological and economic limitations described below. 

technically feasible with current EPA stack emissions 

measurement technology. EPA test methods (e.g., 40 CFR part 60, 

appendix A, Methods 2, 3A, 4, and 10) do not respond adequately 

to the relatively short term and highly variable exhaust gas 

characteristics occurring during these periods. The innate and 

substantial changes in the engine operations during startup 

operations create rapid variations in exhaust gas flow rate as 

well as changes in both pollutant and diluent gas 

concentrations. Correlating the exhaust gas flow rates and the 
92 

gas components concentration data for each fraction of time over 

the entire period of a start up operation is necessary to 

apportion the values appropriately and to determine 

representative average emissions concentrations or total mass 

emissions rate. 

Measuring flow and concentration data in the types of 

rapidly changing exhaust gas conditions characteristic of 

stationary CI engines is unachievable with current technologies 

applicable to stack emissions testing. For example, application 

of Method 2 to measure stack flow rate requires collecting data 

for velocity pressure and stack temperature at each of 12 

traverse points and a corresponding stack moisture and oxygen 

concentration (for molecular weight determination). This 

traverse operation requires about 30 minutes to complete to 

produce a single value for the test period, which is 

approximately the same amount of time as the engine startup 

period.period. An engine’s start-up period could be as long as 

30 minutes. Clearly a single flow rate value would not 

sufficiently represent the variable flow conditions nor allow 

appropriate apportioning of the pollutant concentration 

measurements over that same period for calculating a 

representative average emissions value. Even if thethat startup period is longer than 30 minutes, the stack flow rate test 

period could not be short enough to represent the short term 
93 

(e.g., minute-by-minute) result necessary for representative 

emissions calculations. These findings lead us to conclude that 

correlating the flow and concentration data as necessary to 

determine appropriate proportional contributions to the 

emissions rates or concentrations in calculating representative 

emissions over these short highly variable conditions with 

currently available field testing procedures is problematic for 

stationary CI engines. In addition, even were it technically 

feasible to measure emissions during startups for stationary CI 

engines, the cost of doing so for every startup at every covered 

engine would impose a substantial economic burden. There are 

approximately 936,000 existing stationary CI engines that are 

subject to this rule; the cost for testing every one of these 

engines during engine startup could be more than $1 billion.

EPA is therefore finalizing an operational standard in lieu 

of a numerical emission limit during periods of startup in 

accordance with section 112(h) of the CAA. EPA is limited 

toBased on the information before it, which, of course, includes 

any information provided by the commenters. See 112(d)(3)(A). 

In this case, EPA carefully analyzed all of the information 

before it, including that provided by commenters, and 

determinedcurrently available to the Administrator, we believe

that this standard complies with the requirements of sections

112(d)and 112(d), as provided for in 112(h). The final rule 
94 

requires that owners and operators of stationary engines limit 

the startup time to 30 minutes or less. Engine startup is 

defined as the time from initial start until applied load and 

engine and associated equipment reaches steady state or normal 

operation. For stationary engine with catalytic controls, 

engine startup means the time from initial start until applied 

load and engine and associated equipment reaches steady state or 

normal operation, including the catalyst. EPA is also including 

a requirement in the final rule to 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 otherwise 

applicablenon-startup emission standards apply. As with any 

work practice, CAA section 112(h)(3) and EPA’s implementing 

regulations at 40 CFR 63.6(g) provide that major sources can 

petition the Administrator for approval of an alternative work 

practice, which must be at least as stringent as what is 

required in the regulation. 

Regarding shutdown, EPA determined that it was not 

necessary to establish different standards that would be 

applicable during shutdown for stationary CI engines. The 

commenters did not provide any information that shows emissions 

would be higher during shutdown than during normal operation. 

In addition, commenters are incorrect that compliance with the 
95 

standards must be instantaneous. Compliance with these emission 

standards has always been based on the results of testing that 

is conducted over a three-hour period; EPA has made this more 

explicit in this rule. Since the shutdown period for stationary 

CI engines is typically only a matter of minutes, it is believed 

that even if a shutdown occurred during the performance test, 

the engine would still be able to comply with the emission 

limitation. In a letter dated February 17, 2009 (EPA-HQ-OAR2008-0708-0019), the Engine Manufacturers Association (EMA)

indicates that HAP emissions will be sufficiently controlled 

during periods of shutdown. EMA stated in its letter that 

according to manufacturers, emissions control equipment would 

most likely continue to reduce emissions as designed throughout 

the shutdown period. According to EMA, this is because engine 

emissions control systems and equipment are, during the start of 

an engine shutdown, at high enough temperatures to control HAP 

emissions and will continue to be sufficiently high until the 

engine shuts down. This trend is illustrated in the attachment 

to EMA’s February 17, 2009, letter to EPA, where EMA provided 

two graphs with sample engine shutdown profiles. Figure 2 of 

the attachment to EMA’s letter (EPA-HQ-OAR-2008-0708-0019.1) 

shows catalyst temperatures versus minutes during engine 

shutdown and illustrate stable catalyst temperatures. 
96 

In establishing the standards in this rule, EPA has taken 

into account startup periods and, for the reasons explained 

above, has established different standards for those periods. 

With respect to malfunctions, EPA proposed two options for 

subcategories where the proposed emission standard was based on 

the use of catalytic controls. The first proposed option was to 

have the same standards apply during normal operation and 

malfunctions. The second proposed option was that standards 

during malfunctions be based on emissions expected from the best 

controlled sources prior to the full warm-up of the catalytic 

control. For subcategories where the proposed emission 

standard was not based on the use of catalytic controls, we 

proposed the same emission limitations apply during malfunctions 

and periods of normal operations. EPA is finalizing the first 

option described above, which is that the same standards apply 

during normal operation and malfunctions. In the proposed rule, 

EPA expressed the view that there are different modes of 

operation for any stationary source, and that these modes 

generally include startup, normal operations, shutdown, and 

malfunctions. However, after considering the issue of 

malfunctions more carefully, EPA believes that malfunctions are 

distinguishable from startup, shutdown and normal operations. 

EPA does not view malfunctions as a distinct operating mode and, 

therefore, any emissions that occur at such times do not need to 
97 

be factored into development of CAA section 112(d) standards, 

which, once promulgated, apply at all times. and should not be 

considered a mode of operation for purposes of establishing 

standards under section 112. Periods of startup, normal 

operations, and shutdown are all predictable and routine aspects 

of a source’s operations. However, by contrast, malfunction is 

defined as a “sudden, infrequent, and not reasonably preventable 

failure of air pollution control and monitoring equipment, 

process equipment or a process to operate in a normal or usual 

manner * * * ’’(40 CFR 63.2). Moreover, section 112 uses the 

concept of “best performing” sources in defining MACT, the level 

of stringency that major source standards must meet (including 

work practice standards under section 112(h) because section 

112(h)(1) requires that such standards meet the requirements of 

section 112(d)). We agree with commenters that point out that 

it is not logical to apply the concept of “best performing” to a 

source that is malfunctioning. Although standards for area 

sources are not required to be set based on “best performers,” 

our view is that it is similarly illogical to take into account 

sources that are malfunctioning to determine GACT. Because EPA 

has determined that malfunctions should not be viewed as a 

distinct operating mode, any emissions that occur at such times 

do not need to be factored into development of CAA section 

112(d) standards, which, once promulgated, apply at all times. 
98 

Thus, EPA is not setting separate standards for malfunctions in 

this rule. 

Further, even if malfunctions were considered a distinct 

operating mode, we believe it would be impracticable to take 

into account malfunctions in setting CAA section 112(d) 

standards for stationary CI engines.. Because, by definition, 

malfunctions are sudden and unexpected events, it would be 

difficult to set a standard that would account for the myriad of 

different emissions that could occur during malfunctions of 

stationary CI engines. The type, frequency, and duration of the 

malfunctions may differ significantly between sources. In 

addition, EPA believes that malfunctions will not cause 

stationary CI engines to violate the standard that applies 

during normal operations. Stationary CI engines would in most 

cases shut down immediately or with very little delay in the 

event of a malfunction. Because the standard is expressed as 

the average of three one-hour runs, or a work or management 

practice, any emissions that occur prior to engine shutdown 

should not affect a source’s ability to comply with the 

standard. Commenters' concerns regarding compliance 

certifications should not be a concern for this same reason. 

This approach will also encourage shutdowns as soon as 

practicable when a malfunction that affects emissions occurs. 

In the highly unlikely event that a source fails to comply with 
99 

the applicable CAA section 112(d) standards as a result of a 

malfunction event, EPA would determine an appropriate response 

based on, among other things, the good faith efforts of the 

source to minimize emissions during malfunction periods, 

including preventative and corrective actions, as well as root 

cause analyses to ascertain and rectify excess emissions. We 

intend to closely scrutinize any claim that a CAA section 112(d) 

standard was violated as a result of a malfunction to determine 

whether the event was in fact “sudden, infrequent, not 

reasonably preventable” and was not instead “caused in part by 

poor maintenance or careless operation.” 40 C.F.R. § 63.2 

(definition of malfunction). 

EPA does not agree with the commenter who said that EPA 

should treat SSM emissions as de minimis. It is doubtfulunclear

whether a de minimis exemption is even possible under section 

112(d) of the Act in these circumstances, see National Lime 

Ass’n v. EPA, 233 F. 3d 625, 640 (D.C. Cir, 2000), but in any 

case the commenter provides no specific information to justify 

EPA making such a de minimis finding in this instance. Given 

the very narrow and specific circumstances delineated by the 

court in Alabama Power v. Costle, 636 F.2d 323 (D.C. Cir. 1979) 

for making such a finding, and the lack of specific information 

from the commenter that these circumstances exist in this 

instance, we do not make a de minimis finding. 
100 

E. Emergency Engines

Comment: Several commenters stated that EPA’s proposed 

definition of emergency is not clear as to whether it includes 

emergency engines that operate in emergency demand response (DR) 

programs. The commenter believed that the record on 40 CFR part 

60, subpart IIII, from which the proposed rule definition was 

drawn, clearly indicates that the 40 CFR part 60, subpart IIII 

definition was meant to address peak shaving, not emergency 

engines participating in emergency DR programs. Several 

commenters requested that EPA modify the proposed definition of 

emergency engines to enable engines to maintain their status as 

emergency engines, even though the engines that are used in DR 

programs are part of a financial agreement and based on the 

current definition would not be considered emergency engines. 

Two commenters stated that emergency DR programs should not be 

confused with economic DR programs (e.g., peak shaving). 

Emergency DR programs are initiated by the transmission system 

operators when the threat of power outages is imminent and are 

critical to maintaining available power during periods of 

extreme load on the electric power infrastructure, according to 

the commenters. The events are rare and unplanned, out of the 

control of emergency engine owners/operators, and no power is 

supplied to the grid, but used at the individual facility, the 

commenter said. The commenter said that emergency DR events 
101 

during the year are typically limited to no longer than 2 to 6 

hours per event, with the number of events per year capped by 

the regional power pool. The commenter believed that, by 

establishing a subcategory for generators that serve facilities 

participating in a DR program and that only operate 200 hrs/yr, 

including any hours operated for maintenance purposes, EPA could 

require maintenance practices, and remove any disincentive that 

may be created over the increased administrative burden and 

potential post-combustion control retrofit costs if their 

emergency stationary RICE would be required to be recharacterized as “non-emergency” in order to participate in DR 

programs. The commenter suggested that a 100 hour operating 

limit could also be considered as an alternative. Three 

commenters (stated that they receive many benefits from their 

participation in the local DR program, and that they use 

emergency DR events and tests events to replace some of the 

Joint Commission on Accreditation of Healthcare Organizations’ 

mandated hospital generator tests. According to the commenters 

the costs that they would have to absorb to meet the proposed 

emission limits would be prohibitive and that to require 

facilities to meet rigid emission limits with very little 

reduction in emissions is not encouraged. Emergency engines are 

used throughout the U.S. and provide vital safety requirements 

at hospitals and healthcare institutions, the commenters said. 
102 

Commenters stated that emergency engines participating in 

emergency DR programs provide a critical service in stabilizing 

the electric grid on the rare occasions when the grid is about 

to fail. Many states endorse the use of emergency engines 

participating in emergency DR programs, according to commenter 

82. Two commenters cited various DR programs in the New England 

area that existing engines participate in. A commenter provided 

detailed discussion of several emergency DR programs across the 

country, including states in New England, the Mid Atlantic and 

Midwest, and the South, that are supportive of using emergency 

engines as part of their emergency DR programs, and that 

accommodate operation of these engines through various 

definitions of emergency, or through permitting. The commenter 

concluded that it is very important that EPA not adopt rules 

that conflict with how much of the U.S. handles emergency DR. 

Response: EPA agrees that it would be appropriate to allow 

emergency engines to operate as part of emergency demand 

response programs for a limited number of hours of operation per 

year in situations where grid failure and a blackout are 

imminent. In the final rule, EPA has revised the requirements 

for emergency engines to reflect this. 

F. Emissions Data

Comment: Multiple commenters believe that the emissions 

data for engines is not adequate to conduct an appropriate MACT 
103 

floor analysis. EPA should collect additional data and redo the 

MACT floor analysis, according to numerous commenters. The 

commenters also stated that EPA did not consider emissions 

variability in setting the MACT floor. 

 Commenters stated that the MACT floors should not be based 

on data using single measurements, when three measurements are a 

standard requirement for demonstrating compliance. In the 

absence of multiple measurements, outliers and erroneous errors 

cannot be caught, according to the commenters. 

 The commenters said that EPA should use data from units of 

similar size to set standards for sources of the same size, 

e.g., emissions from a large engine should not be used to set 

standards for a 100 HP engine unless EPA can demonstrate that 

such an assumption is justified. The commenters are concerned 

that the data EPA has used for the MACT floor analysis is not 

representative of the current population of engines. 

Commenters criticized the applicability and use of the RICE 

emissions database as representative of the engines being 

regulated. One commenter noted that the 40 ppmvd numerical 

emissions limit for CO appears to be based on 10 tests of only 

one make and model of engine (Caterpiller, Model No. 3508) over 

a 3-day period in the Research and Development Laboratory of CSU 

in 1999 (Docket No. EPA-HQ-OAR-2008-0708-0006). The commenter 

states that according to the engine population data presented in 
104 

the impacts document in the docket (Docket No. EPA-HQ-OAR-2008-

0798-0028) the promulgated rule would impose limits on more than 

50,000 CI engines. The commenter believed that basing the limit 

on such a small and unrepresentative sample jeopardizes the 

accuracy of any assumptions made about the operational 

conditions or performance of the regulated population as well as 

the accuracy of any cost of compliance estimates, and leads to 

an underestimation of the impact of the rule. 

 Response: Section 112(d)(3) of the CAA requires EPA to set 

MACT standards based on the test data that is available to the 

Agency and this is what EPA did at proposal. EPA recognizes 

that it had limited emissions test data at the time it developed 

the proposed rule. However, EPA notes that it used the data 

that was available at the time of proposal. EPA requested 

additional test data to supplement the emissions database during 

the development of previous rules for stationary engines and 

also in an advance notice of proposed rulemaking for this rule 

and did not receive any data. EPA again requested additional 

test data during the comment period for the current engine 

rulemaking and made an additional effort post-proposal to reach 

out to industry and other sources in order to supplement the 

existing emission data set. EPA did receive additional 

emissions data for stationary CI engines during the postproposal period for this rulemaking. The additional data 
105 

include tests for 11 stationary engines, ranging in size from 

160 HP to 3,570 HP. The inclusion of this additional data in 

the MACT floor analysis for the final rule addresses the 

commenters’ concerns about using data for one large engine to 

set the MACT floor for smaller engines. 

 EPA understands the concerns of commenters with regard to 

whether the MACT floor analysis for the proposed rule took 

emissions variability appropriately into account. EPA took 

emissions variability into account to a greater degree when 

conducting the MACT floor analysis for the final rule. For 

engines where EPA had data for multiple tests on the same 

engine, EPA used the highest test run concentration as the 

representative emissions for that engine. EPA also used the 

lowest percent reduction observed in determining the percent 

reduction expected from applicable aftertreatment controls in 

determining beyond-the-floor MACT standards. Therefore, the 

variability in emissions from the engine was factored into the 

MACT floor analysis and the beyond-the-floor MACT analysis. 

 EPA does not agree that it would be inappropriate to use 

data from one run in setting MACT floors; using the highest run 

from the testing takes into account the variability of 

emissions. 

G. Final Rule Impacts
106 

Comment: Several commenters expressed that the costs are 

not representative of actual costs of implementing the rule and 

numerous commenters said that the proposed rule will have a 

significant financial impact on their sources. According to the 

commenters, EPA has underestimated the cost impacts of the rule 

by an order of magnitude or more. Numerous commenters indicated 

that EPA has used old, faulty, and inappropriate data on the 

cost of controls, testing, recordkeeping and reporting to 

estimate the economic impacts of the rule. Commenters said that 

EPA should gather current information on the cost of controls 

and redo the cost calculations. The commenters provided 

specific examples of where they believe EPA has used 

inappropriate cost information. One concern expressed was that 

the cost of oxidation catalyst control for diesel engines was 

based on the cost of oxidation catalyst control for gas engines. 

Commenters also said that not all existing engines have hour 

meters. Commenters believed that EPA has underestimated the 

total cost of this rule by underestimating the number of engines 

requiring the addition of catalyst; assuming that catalysts can 

simply be added to effectively control existing engines; 

overlooking the significant cost of field installation; and 

underestimating the complexity of and administrative/operational 

burdens added by this rule. 
107 

Several commenters provided comments about the economic 

impact of the rule on emergency units. One commenter stated 

that overall the cost per ton of HAP or CO removal would be 

excessive for emergency CI engines since emissions were well 

below a ton/yr and the units use is very limited and 

intermittent. Another commenter noted that engine manufacturers 

do not recommend the use of after treatment devices for 

emergency engines, and that EPA appeared to support that 

position in the Regulatory Impact Analysis (RIA), which states 

that cost per ton removal of HAP ranged from $1 million to $2.8 

million for engines larger than 500 HP and from $3.7 million to 

$8.7 million for engines between 50 and 500 HP. One commenter 

said EPA does not appear to consider any costs associated with 

testing emergency engines, even though owners may deem it 

prudent to test to confirm they are meeting the standard rather 

than risk an enforcement action if the unit does not meet the 

standard. Testing to comply with the 100 percent load 

requirement will require owners to purchase or rent load banks 

to meet the conditions contemplated in the standard, which can 

cost up to $10,000 per site. The load bank costs alone could 

add up to as much as $973 million. In addition, equipment 

modifications (sample ports) would be necessary to test 

emissions, and EPA has not included these costs in its 

calculations. 
108 

One commenter said that the proposed rule for existing CI 

engines greater than 300 HP at area sources is cost prohibitive 

for facilities with peak shaving engines with low operating 

hours. The commenter estimated that the cost per ton of HAP 

removed from these units would range from $200,000 to $1 

million, similar to the cost for emergency generators. 

While reducing HAP is an important goal, one commenter 

believed that the overbroad approach taken by EPA in subjecting 

all the RICE equipment in question to the requirements proposed, 

regardless of whether the equipment is located in urban or rural 

areas, particularly when considering the Congressional intent of 

reducing HAP in urban areas given the potential risks to public 

health, and the imposition of costs in excess of $528 million to 

reduce 13,000 tons of HAP a year (i.e., a cost of $40,615 per 

ton) should be carefully scrutinized. 

 One commenter noted an additional concern with the proposed 

rule is the potential impact of parasitic load resulting from 

the use of catalytic diesel particulate filters (CDPF) and 

oxidation catalysts. Some back pressure penalty is associated 

with the use of both CDPF and oxidation catalysts methods to 

control HAP, the back pressure can increase with time, which may 

require regeneration of the catalyst or changing filters. The 

commenter believed that for those utilities that operate RICE 

with only marginal excess capacity, addition of either type of 
109 

control could require installation of additional RICE capacity 

to maintain the needed reliability level. The commenter noted 

that it will not be possible to design around the pressure drop 

for existing engines and that the penalty should have been 

addressed and included by EPA in the cost assessment of retrofit 

and operation for the control devices. 

Another commenter indicated that EPA’s estimates are low 

for the capital and operating costs associated with the use of 

catalytic control, and are based on pricing data from one vendor 

and a limited number of data points. The commenter asserted 

that EPA’s capital estimate and annual operating cost estimate 

for catalytic controls are each low by an order of magnitude of 

2 to 3. The commenter also stated that because beyond-the-floor 

standards (which require catalytic controls) are based on the 

cost per ton of HAP removed and EPA significantly underestimated 

capital and operating costs of catalytic controls, EPA must 

reanalyze the proposed rule with better cost data to determine 

when catalysts are economically practical. 

 One commenter said the cost information contained in the 

docket for test costs is not representative of the sampling 

costs required to comply with the standards as proposed. 

Members of the commenter’s organization indicated that the cost 

per sample run using Methods 1, 3, 4, and 10 could easily exceed 

$10,000, excluding costs to prepare for the sampling (i.e., 
110 

scaffolding, stack extensions, etc.). In addition to these cost 

considerations, as a practical matter, there would be 

significant difficulty in performing these EPA test methods on 

engine exhaust. 

The commenter claimed that EPA has proposed compliance 

requirements that are more stringent than GACT requirements or 

management practices and that EPA has decided to institute MACT. 

However, even under MACT EPA can consider cost and energy 

impacts. The commenter disagreed with EPA’s conclusion in the 

RIA that the rule will not likely have a significant impact on 

the supply, distribution, or use of energy. The commenter said 

that the proposed standards could have a very detrimental impact 

on energy reliability, and many units may have to be shut down 

due to the cost of compliance. 

Response: EPA used the information it had available at the 

time of proposal to estimate the cost impacts associated with 

the rule. This information included cost data obtained for the 

development of previous stationary engine rulemakings, which EPA 

believed would be appropriate to use for this rulemaking. Based 

on the significant number of comments received on the proposed 

rule costs, EPA revisited its cost analysis and assumptions 

underlying the proposed rule and revised that analysis and 

assumptions in the final rule. 
111 

 EPA has made several attempts to obtain more current cost 

information, including through an advance notice of proposed 

rulemaking for this rule. EPA agrees with the commenters that 

it is inappropriate to base the cost for a diesel oxidation 

catalyst on the costs for oxidation catalysts for spark ignition 

engines. Therefore, EPA has based the catalyst cost estimate in 

the final rule on cost data for diesel oxidation catalysts 

obtained from a CARB study. More information on the cost 

estimate can be found in the memorandum entitled “Control Costs 

for Existing Stationary CI RICE.” The cost estimates are based 

on the use of diesel oxidation catalyst rather than CDPF because 

we believe that sources will choose to use oxidation catalyst 

control because they are less costly than CDPF and achieve 

similar reduction in HAP. Based on a reanalysis of the MACT 

floor data and above-the-floor options, taking variability into 

account, the final rule requires engines equipped with catalysts 

to achieve 70 percent reduction rather than the 90 percent that 

was proposed. 

Regarding the comment that catalysts cannot be added to 

existing engines, the commenter did not provide any information 

to show what engines would not be able to be retrofit. 

Regarding the concerns expressed about backpressure increases, 

the commenter did not provide any data to support the claim that 
112 

the backpressure increases are so high that they would severely 

impact the engine output. 

EPA does not agree with the claim that the rule will put a 

strain on hospitals. The stationary diesel engines at hospitals 

are typically emergency engines and EPA has determined that 

emergency engines located at institutional facilities such as 

hospitals that are area sources are not part of the listed 

source category and are therefore not subject to the final rule. 

EPA does not agree with the commenters that it is not 

appropriate to require peaking units and stationary diesel 

engines that are located in rural areas to install controls. 

This is discussed in more detail in the summary of comments and 

responses. EPA has specified in the final rule that performance 

testing is not limited to 100 percent load, so it should not be 

necessary to include the cost of a load bank in the performance 

testing cost. EPA has incorporated the costs for testing, 

monitoring, recordkeeping, and reporting in the cost analysis 

and believes that its estimates for these costs are appropriate. 

The costs for testing are based on information from source 

testing companies. As a result of the comments on testing 

costs, EPA reevaluated the estimate of how many engines could be 

tested in a single day and determined that two engines could be 

tested at a facility in one day, rather than three as was 

estimated in the proposal. 
113 

 Regarding the concerns expressed by the commenters about 

the impact of the rule on emergency engines, the final rule 

requires existing stationary emergency engines to meet work 

practice or management practice standards, rather than numeric 

emission limitations; these work practices and management 

practices do not require that these engines be retrofit with 

aftertreatment controls or be performance tested to determine 

compliance. Information provided to EPA by engine manufacturers 

indicates that most engines are already equipped with an hour 

meter; therefore, EPA did not add this cost into the rule. EPA 

does not believe that the final rule will cause owners/operators 

to replace their emergency engines. The final rule imposes work 

or management practices on these engines, which EPA believes 

will not be overly burdensome to facilities and will not cause 

the retirement of existing stationary emergency engines. 

VI. Summary of Environmental, Energy and Economic Impacts

A. What are the air quality impacts?

 The final rule is expected to reduce total HAP emissions 

from stationary RICE by 1,010 tons per year (tpy) beginning in 

the year 2013 or the first year the rule will become effective. 

EPA estimates that over 900,000 stationary CI engines will be 

subject to the rule. These estimates include stationary engines 

located at major and area sources; however, not all stationary 

engines are subject to numerical emission standards. Further 
114 

information regarding the estimated reductions of the final rule 

can be found in the memorandum entitled “Impacts Associated with 

NESHAP for Existing Stationary RICE,” which is available in the 

docket. 

 In addition to HAP emissions reductions, the final rule 

will reduce other pollutants such as CO, PM, SOx, and volatile 

organic compounds (VOC). The final rule is expected to reduce 

emissions of CO by 14,000 tpy in the year 2013. Reductions of 

PM are estimated at 2,800 tpy in the year 2013. Emissions of 

VOC are estimated to be reduced by 27,000 tpy in the year 2013. 

The final rule will also reduce emissions of SOx through the use 

of ULSD. We have not quantified the SOx reductions that would 

occur as a result of engines switching to ULSD because we are 

unable to estimate the number of engines that already use ULSD 

and therefore we are unable to estimate the percentage of 

engines that may switch to ULSD due to this rule. If none of 

the affected engines would use ULSD without this rule, then we 

estimate the SOx reductions are 31,000 tpy in the year 2013. If 

all of the affected engines would use ULSD regardless of the 

rule, then the additional SOx reductions would be zero. 

B. What are the cost impacts?

The total national capital cost for the final rule for 

existing stationary RICE is estimated to be $744 million, with a 

total national annual cost of $374 million in year 2013 (the 
115 

first year the rule is implemented). Further information 

regarding the estimated cost impacts of this proposed rule can 

be found in the memorandum entitled “Impacts Associated with 

NESHAP for Existing Stationary CI RICE,” which is available in 

the docket. 

C. What are the benefits?

 We calculated the benefits of this rule in terms of the cobenefits associated with reducing fine particulate matter (PM) 

rather than calculating the benefits associated with reducing 

hazardous air pollutants (HAPs). These PM reductions are a 

consequence of the technologies installed to reduce HAP 

emissions from RICE. We estimate the monetized PM2.5 co-benefits 

of this final regulatory action to be $940 million to $2.3 

billion (2008$, 3 percent discount rate) in the fifth year 

(2013). The PM2.5 co-benefits at a 7 percent discount rate are 

$850 million to $2.1 billion (2008$). Because the magnitude of 

the PM2.5 co-benefits is largely driven by the concentrationresponse function for premature mortality, we examined alternate 

relationships between PM2.5 and premature mortality supplied by 

experts. Higher and lower co-benefits estimates are plausible, 
116 

but most of the expert-based estimates fall between these two 

estimates above.4

A summary of the monetized co-benefits estimates at 

discount rates of 3 percent and 7 percent is in Table 4 of this 

preamble. 

 Table 4. Summary of the Monetized PM2.5 Co-benefits 

Estimates for Final RICE NESHAP (millions of 2008$) 

Pollutant 

Emission 

reductions 

(tons) 

Total monetized 

co-benefits 

(3% Discount) 

Total monetized 

co-benefits 

(7% Discount) 

Direct PM2.5 2,844 $910 to $2,200 $820 to $2,000 

PM2.5 Precursors 

VOC 27,395 $33 to $82 $30 to $74 

 Total: $940$1,100 to 

$2,300$2,600

$850$960 to 

$2,100$2,300

1

All estimates are for the analysis year (the fifth year), and 

are rounded to two significant figures so numbers may not sum 

across rows. All fine particles are assumed to have equivalent 

health effects, but the benefit-per-ton estimates vary between 

precursors because each ton of precursor reduced has a different 

propensity to form PM2.5. We assume that all PM reductions for 

this rule are PM2.5 reductions. Benefits from reducing hazardous 

air pollutants (HAPs) are not included. 

The benefits estimates of population-level improvements to 

human health from reductions in PM2.5 air pollution. We generated 

estimates that represent the total monetized human health cobenefits (the sum of premature mortality and morbidity) of 

 

4

 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. 

Formatted: Complex Script Font: Times New

Roman, 10 pt, Subscript
117 

reducing a ton of PM2.5 and PM2.5 precursor emissions. We base 

the estimate of human health co-benefits derived from the PM2.5

and PM2.5 precursor emission reductions on the general approach 

and methodology laid out in the Technical Support Document that 

accompanied the RIA for the 2008 National Ambient Air Quality 

Standard for Ground-level Ozone (NAAQS) and Fann et al. (2009).5

 

To generate the benefit-per-ton estimates, we used a model 

to convert emissions of direct PM2.5 and PM2.5 precursors into 

changes in PM2.5 air quality and another model to estimate the 

changes in human health based on that change in air quality. 

Finally, the monetized health co-benefits were divided by the 

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

Even though we assume that all fine particles have equivalent 

health effects, the benefit-per-ton estimates vary between 

precursors because each ton of precursor reduced has a different 

propensity to form PM2.5. For example, SOX has a lower benefitper-ton estimate than direct PM2.5 because it does not form as 

much PM2.5, thus the exposure would be lower, and the monetized 

health co-benefits would be lower. 

For context, it is important to note that the magnitude of 

the PM benefits is largely driven by the concentration response 

function for premature mortality. Experts have advised EPA to 

 

5

 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. 
118 

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. For this final rule we cite two key 

empirical studies, one based on the American Cancer Society 

cohort study6 and the extended Six Cities cohort study.7 

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. The question of whether or not to assume a threshold 

in calculating the co-benefits associated with reductions in 

PM2.5 is an issue that affects the benefits calculations for many 

EPA rulemakings and analyses. Due to these implications, we 

solicited comment on appropriateness of both the no-threshold 

and threshold model for PM benefits analysis as part of the 

Portland Cement NESHAP (May 2009). The comment period closed on 

September 4, 2009, and EPA is still reviewing those comments. 

Since then, EPA finalized the Integrated Science Assessment for 

 

6

 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

7

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

Pollution and Mortality.” American Journal of Respiratory and 

Critical Care Medicine. 173: 667-672
119 

Particulate Matter8, which was reviewed by EPA’s Clean Air 

Scientific Advisory Committee. Based on EPA’s review of the 

body of scientific literature and the Integrated Science 

Assessment, EPA has concluded that the no-threshold model most 

adequately portrays the relationship between fine particles and 

premature mortality. Although this document does not 

necessarily represent agency policy, it provides a basis for 

reconsidering the application of thresholds in PM2.5 

concentration-response functions used in EPA’s RIAs. 

The PM2.5 co-benefits for the incremental emission reductions 

from this final regulatory action reflect EPA’s most current 

interpretation of the scientific literature, including four key 

changes from previous analyses for refineries: (1) a nothreshold model for PM2.5 that calculates incremental co-benefits 

down to the lowest modeled air quality levels; (2) a revised 

Value of a Statistical Life (VSL); (3) two technical updates to 

the population dataset and aggregation method; and (4) 

presentation of results derived from Pope et al. (2002) and 

Laden et al. (2006) instead of using the extremes of EPA’s 

Expert Elicitation on PM Mortality (Roman et al., 2008). For 

more information on the updates to the benefit estimates, please 

 

8

 U.S. Environmental Protection Agency (U.S. EPA). 2009. Integrated Science 

Assessment for Particulate Matter (Final Report). EPA-600-R-08-139F. 

National Center for Environmental Assessment – RTP Division. December. 

Available on the Internet at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546.
120 

refer to the RIA for this rule, which is available in the 

docket. 

 It should be noted that the PM2.5 co-benefits estimates 

provided above do not include benefits from reduced hazardous 

air pollutants, improved visibility, reduced aquatic and 

terrestrial acidification. The benefits from reducing 1,014 

tons of HAPs each year have not been monetized in this analysis. 

We do not have sufficient information or modeling available to 

provide such estimates for this rulemaking. In addition, we 

have not quantified the benefits attributable to the SO2

reductions that would occur as a result of these engines 

switching to ULSD. Although we are confident that some SO2

reductions would occur as a result of this rule, we are unable 

to estimate the percentage of engines that may switch to ULSD in 

the absence of this rule or the number of engines that already 

use ULSD. As a PM2.5 precursor, these SO2 emission reductions 

would lead to fewer PM2.5-related health effects. Because of 

uncertainty in the magnitude of the attributable SO2 reductions 

and to avoid the appearance of double-counting, we have chosen 

to not include these estimates in the results table shown above. 

If none of the affected engines would use ULSD without this 

rule, then we estimate the additional monetized PM2.5-related 

health co-benefits would be $720$730 million to $1.8 billion in 

2013 (2008$, 3% discount rate). If all of the affected engines 
121 

would use ULSD regardless of the rule, then the additional 

monetized co-benefits from SO2 reductions would be zero. 

 This analysis does not include the type of detailed 

uncertainty assessment found in the 2006 PM2.5 NAAQS RIA because 

we lack the necessary air quality input and monitoring data to 

run the benefits model. However, the 2006 PM2.5 NAAQS benefits 

analysis provides an indication of the sensitivity of our 

results to the use of alternative concentration response 

functions, including those derived from the PM expert 

elicitation study. 

 The costs of this rulemaking are estimated to be $374 

million (2008$) in the fifth year, and the monetized PM2.5 cobenefits are estimated at $940 million to $2.3 billion (2008$, 3 

percent discount rate) for that same year. The co-benefits at a 

7 percent discount rate are $850 million to $2.1 billion 

(2008$). Thus, net benefits of this rulemaking are estimated at 

$570 million to $1.9 billion (2008$, 3 percent discount rate)and 

$480 million to $1.7 billion (2008$, 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 the two estimates we present above. EPA believes 

that the co-benefits are likely to exceed the costs even when 
122 

taking into account the uncertainties in the cost and benefit 

estimates. 

 For more information on the benefits analysis, please refer 

to the RIA for this rulemaking, which is available in the 

docket. 

D. What are the economic impacts?

The economic impact analysis (EIA) that is included in the 

RIA indicates that prices of affected output from the affected 

industries will increase as a result of the rule, but the 

changes will be small. The largest impacts are on the electric 

power generating industry because it bears more costs from the 

rule than any other affected industry (nearly 80 percent of the 

total annualized costs). For all affected industries, 

annualized compliance costs are 0.6 percent or less on average 

of sales for firms. Thus, output prices will not increase more 

than 0.6 percent for consumers and producers affected by this 

rule. 

Based on the estimated compliance costs associated with 

this rule and the predicted changes in prices and output in 

affected markets, the estimated social costs are $374 million 

(2008 dollars), which is the same as the estimated compliance 

costs. 
123 

 For more information on the benefits analysis, please 

refer to the RIA for this rulemaking, which is available in the 

docket. 

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

impacts?

EPA does not anticipate any significant non-air health, 

environmental or energy impacts as a result of the final rule. 

VII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and 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 or 

adversely affect in a material way the economy, a sector of the 

economy, productivity, competition, jobs, the environment, 

public health or safety, or State, local, or tribal governments 

or communities. 

Accordingly, EPA submitted this action to the Office of 

Management and Budget (OMB) for review under EO 12866 and any 

changes made in response to OMB recommendations have been 

documented in the docket for this action. 

B. Paperwork Reduction Act

 The information collection requirements in the final rule 

have been submitted for approval to OMB under the Paperwork 
124 

Reduction Act, 44 U.S.C. 3501 et seq. The information 

collection requirements are not enforceable until OMB approves 

them. 

 The information collection activities in this final rule 

include performance testing for non-emergency engines larger 

than 100 HP, one-time notifications and periodic reports, 

recording information, monitoring and the maintenance of 

records. The information generated by these activities will be 

used by EPA to ensure that affected facilities comply with the 

emission limits and other requirements. Records and reports are 

necessary to enable EPA or States to identify affected 

facilities that may not be in compliance with the requirements. 

Based on reported information, EPA will decide which units and 

what records or processes should be inspected. The amendments 

do not require any notifications or reports beyond those 

required by the General Provisions. The recordkeeping 

requirements require only the specific information needed to 

determine compliance. These recordkeeping and reporting 

requirements are specifically authorized by CAA section 114 (42 

U.S.C. 7414). All information submitted to EPA for which a 

claim of confidentiality is made will be safeguarded according 

to EPA policies in 40 CFR part 2, subpart B, Confidentiality of 

Business Information. 
125 

 The annual monitoring, reporting, and recordkeeping burden 

for this collection (averaged over the first 3 years after 

sources must comply) is estimated to be 2,262,272 labor hours 

per year at a total annual cost of $4,200,492. This estimate 

includes notifications of compliance and performance tests, 

engine performance testing, semiannual compliance reports, 

continuous monitoring, and recordkeeping. The total capital 

costs associated with the requirements over the 3-year period of 

the ICR is estimated to be $20,444,316 per year. There are no 

additional operation and maintenance costs for the requirements 

over the 3-year period of the ICR. Burden is defined at 5 CFR 

1320.3(b). 

 An Agency may not conduct or sponsor, and a person is not 

required to respond to a collection of information unless it 

displays a currently valid OMB control number. The OMB control 

numbers for EPA’s regulations in 40 CFR are listed in 40 CFR 

part 9. When this ICR is approved by OMB, the Agency will 

publish a technical amendment to 40 CFR part 9 in the Federal

Register to display the OMB control number for the approved 

information collection requirements contained in this final 

rule. 

C. Regulatory Flexibility Act

 The Regulatory Flexibility Act (RFA) generally requires an 

agency to prepare a regulatory flexibility analysis of any rule 
126 

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 final 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-forprofit 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 Small Business Administration (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 in. 

The SBA defines a small business in terms of the maximum 

employment, annual sales, or annual energy-generating capacity 

(for electricity generating units—EGUs) of the owning entity. 
127 

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 RICE; therefore, a number of 

size standards are utilized in this analysis. For the 9 

industries identified at the 6-digit NAICS code represented in 

this analysis, the employment size standard varies from 500 to 

1,000 employees. The annual sales standard is as low as 0.75 

million dollars and as high as 34 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 (MW-hr) 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 final 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 

this final action to all affected small entities across all 

industries affected. We estimate that all small entities will 
128 

have annualized costs of less than 1 percent of their sales in 

all industries except NAICS 2211 (electric power generation, 

transmission, and distribution) and NAICS 111 (Crop and Animal 

Production). For these industries, the number of small entities 

having annualized costs of greater than 1 percent of their sales 

is less than 5 percent. Hence, we conclude that there is no 

significant economic impact on a substantial number of small 

entities (SISNOSE) for this rule. 

For more information on the small entity impacts associated 

with the final rule, please refer to the Economic Impact and 

Small Business Analyses in the public docket. These analyses 

can be found in the Regulatory Impact Analysis for this final 

rule. 

Although the final rule would not have a significant 

economic impact on a substantial number of small entities, EPA 

nonetheless tried to reduce the impact of the final 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 this rule, we are applying the minimum level of 

control (i.e., the MACT floor) to small engines and emergency 

engines located at major HAP sources and the minimum level of 
129 

testing, monitoring, recordkeeping, and reporting to affected 

RICE sources, both major and area, allowed by the CAA. Other 

alternatives considered that provided more than the minimum 

level of control were deemed as not technically feasible or 

cost-effective for EPA to implement for small engines and 

emergency engines as explained earlier in the preamble. 

D. Unfunded Mandates Reform Act of 1995

Title II of the Unfunded Mandates Reform Act of 1995 

(UMRA), 2 U.S.C. 1531–1538, requires Federal agencies, unless 

otherwise prohibited by law, to assess the effects of their 

regulatory actions on State, local, and tribal governments and 

the private sector. This final rule contains 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 1 year. Accordingly, EPA has prepared 

under section 202 of the UMRA a written statement which is 

summarized below. 

As discussed previously in this preamble, the statutory 

authority for the final rule is section 112 of the CAA. Section 

112(b) lists the 189 chemicals, compounds, or groups of 

chemicals deemed by Congress to be HAP. These toxic air 

pollutants are to be regulated by NESHAP. Section 112(d) of the 

CAA directs us to develop NESHAP based on MACT, which require 

existing and new major sources to control emissions of HAP. EPA 
130 

is required to address HAP emissions from stationary RICE 

located at area sources under section 112(k) of the CAA, based 

on criteria set forth by EPA in the Urban Air Toxics Strategy 

previously discussed in this preamble. These NESHAP apply to 

existing stationary CI RICE less than or equal to 500 HP located 

at major sources of HAP emissions, existing non-emergency 

stationary CI RICE greater than 300 HP, and existing stationary 

CI RICE located at area sources of HAP emissions. 

In compliance with section 205(a), we identified and 

considered a reasonable number of regulatory alternatives. EPA 

carefully examined the The regulatory alternatives, and selected

upon which the rule is based is the lowest cost/least 

burdensomecostly, most cost-effective alternative that EPA deems 

adequate to achieve the statutory requirements of Clean Air Act 

section 112 and effectively reduce emissions of HAP..

1. Social Costs and Benefits 

The RIA prepared for the final rule, including the Agency’s 

assessment of costs and benefits, is detailed in the “Regulatory 

Impact Analysis for the Final RICE NESHAP” in the docket. Based 

on estimated compliance costs on all sources associated with the 

final rule and the predicted change in prices and production in 

the affected industries assuming passthrough of costs to 

affected consumers, the estimated social costs of the final rule 

are $374 million (2008 dollars). It is estimated that by 2013, 
131 

HAP will be reduced by 1,010 tpy due to reductions in 

formaldehyde, acetaldehyde, acrolein, methanol and other HAP 

from existing stationary RICE. Formaldehyde and acetaldehyde 

have been classified as “probable human carcinogens.” Acrolein 

and the other HAP are not considered carcinogenic, but produce 

several other toxic effects. The final rule is expected to 

reduce emissions of CO by more than 14,000 tpy in the year 2013. 

Reductions of PM are estimated at 2,800 tpy in the year 2013. 

Emissions of VOC are estimated to be reduced by 27,000 tpy in 

the year 2013. Exposure to CO can affect the cardiovascular 

system and the central nervous system. 

The total monetized benefits of the final rule range from 

$940 million to $2.3 billion. (2008 dollars). 

2. Future and Disproportionate Costs 

The UMRA requires that we estimate, where accurate 

estimation is reasonably feasible, future compliance costs 

imposed by the rule and any disproportionate budgetary effects. 

Our estimates of the future compliance costs of the final rule 

are discussed previously in this preamble. We do not believe 

that there will be any disproportionate budgetary effects of the 

final rule on any particular areas of the country, State or 

local governments, types of communities (e.g., urban, rural), or 

particular industry segments. 

3. Effects on the National Economy 
132 

The UMRA requires that we estimate the effect of the final 

rule on the national economy. To the extent feasible, we must 

estimate the effect on productivity, economic growth, full 

employment, creation of productive jobs, and international 

competitiveness of the U.S. goods and services if we determine 

that accurate estimates are reasonably feasible and that such 

effect is relevant and material. The nationwide economic impact 

of the final rule is presented in the “Regulatory Impact 

Analysis for RICE NESHAP” in the docket. This analysis provides 

estimates of the effect of the final rule on most of the 

categories mentioned above. The results of the economic impact 

analysis were summarized previously in this preamble. In 

addition, we have determined that the final rule contains no 

regulatory requirements that might significantly or uniquely 

affect small governments. Therefore, this rule is not subject to 

the requirements of section 203 of the UMRA. 

E. Executive Order 13132: Federalism

 This final rule does not have federalism implications. It 

will not have substantial direct effects on the States, on the 

relationship between the national government and the States, or 

on the distribution of power and responsibilities among the 

various levels of government, as specified in Executive Order 

13132. The final rule primarily affects private industry, and 

does not impose significant economic costs on State or local 
133 

governments. Thus, Executive Order 13132 does not apply to the 

final rule. 

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 the final rule. 

G. Executive Order 13045: Protection of Children from 

Environmental Health and Safety Risks

EPA interprets Executive Order 13045 (62 FR 19885, 

April 23, 1997) as applying to those regulatory actions 

that concern health or safety risks, such that the analysis 

required under section 5-501 of the 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
134 

This final rule 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 impact on 

the supply, distribution, or use of energy. EPA has prepared an 

analysis of energy impacts that explains this conclusion as 

follows below. 

With respect to energy supply and prices, our analysis 

suggests that at the industry level, the annualized costs 

represent a very small fraction of revenue (generally less than 

0.6 percent). As a result, we can conclude supply and price 

impacts on affected energy producers and consumers should be 

small. 

To enhance understanding regarding the regulation’s 

influence on energy consumption, we examined publicly available 

data describing energy consumption for the electric power 

sector. The electric power sector is expected to incur about 80 

percent of the $374$380 million in compliance costs associated 

with the final rule, and is the industry expected to incur the 

greatest share of the costs relative to other affected 

industries. The Annual Energy Outlook 2010 (EIA, 2009) provides 

energy consumption data. Since this final rule only affects 

diesel-fired RICE, our analysis focuses on impacts of 

consumption of these fuels. As shown in Table 5 of this 

preamble,section, the electric power sector accounts for less 
135 

than 0.5 percent of the U.S. total liquid fuels (which includes 

diesel fuel). As a result, any energy consumption changes 

attributable to the final rule should not significantly 

influence the supply, distribution, or use of energy nationwide. 
136 

Table 5. U.S. Electric Powera Sector Energy Consumption 

(Quadrillion BTUs): 2013 

Quantity 

Share of Total Energy 

Use 

Distillate fuel oil 0.12 0.1% 

Residual fuel oil 0.34 0.3% 

Liquid fuels subtotal 0.45 0.5% 

Natural gas 5.17 5.1% 

Steam coal 20.69 20.6% 

Nuclear power 8.59 8.5% 

Renewable energyb 6.06 6.0% 

Electricity Imports 0.09 0.1% 

Total Electric Power Energy 

Consumptionc

 41.18 40.9% 

Delivered Energy Use 72.41 72.0% 

Total Energy Use 100.59 100.0% 

a

Includes consumption of energy by electricity-only and combined heat and 

power plants whose primary business is to sell electricity, or electricity 

and heat, to the public. Includes small power producers and exempt wholesale 

generators. 

b

Includes conventional hydroelectric, geothermal, wood and wood waste, 

biogenic municipal solid waste, other biomass, petroleum coke, wind, 

photovoltaic and solar thermal sources. Excludes net electricity imports. 

c

Includes non-biogenic municipal waste not included above. 

Source: U.S. Energy Information Administration. 2009. Supplemental Tables to 

the Annual Energy Outlook 2010. 

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and 

Advancement Act (NTTAA) of 1995 (Public Law No. 104-113, Section 

12(d), 15 U.S.C. 272 note) directs EPA to use voluntary 

consensus standards (VCS) in its regulatory activities, unless 

to do so would be inconsistent with applicable law or otherwise 

impractical. The VCS are technical standards (e.g., materials 

specifications, test methods, sampling procedures, and business 

practices) that are developed or adopted by VCS bodies. The 
137 

NTTAA directs EPA to provide Congress, through OMB, explanations 

when the Agency does not use available and applicable VCS. 

This final rulemaking does not involve technical standards. 

Therefore, EPA did not consider the use of any voluntary 

consensus standards. 

 Under §63.7(f) and §63.8(f) of Subpart A of the General 

Provisions, a source may apply to EPA for permission to use 

alternative test methods or alternative monitoring requirements 

in place of any required or referenced testing methods, 

performance specifications, or procedures. 

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations

Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) 

establishes federal executive policy on environmental justice. 

Its main provision directs federal agencies, to the greatest 

extent practicable and permitted by law, to make environmental 

justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies, and 

activities on minority populations and low-income populations in 

the United States. 

EPA has determined that this final rule will not have 

disproportionately high and adverse human health or 
138 

environmental effects on minority or low-income populations 

because it increases the level of environmental protection for 

all affected populations without having any disproportionately 

high and adverse human health or environmental effects on any 

population, including any minority or low-income population. 

This rule is a nationwide standard that reduces air toxics 

emissions from existing stationary CI engines, thus decreasing 

the amount of such emissions to which all affected populations 

are exposed. 

K. Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et seq., as 

added by the Small Business Regulatory Enforcement Fairness Act 

of 1996, generally provides that before a rule may take effect, 

the agency promulgating the rule must submit a rule report, 

which includes a copy of the rule, to each House of the Congress 

and to the Comptroller General of the United States. EPA will 

submit a report containing this final rule and other required 

information to the U.S. Senate, the U.S. House of 

Representatives, and the Comptroller General of the United 

States prior to publication of the rule in the Federal Register. 

A major rule cannot take effect 
National Emission Standards for Hazardous Air Pollutants for 

Reciprocating Internal Combustion Engines 

Page 139 of 201 

until 60 days after it is published in the Federal Register. 

This action is a “major rule” as defined by 5 U.S.C. 804(2). 

The final rule will be effective on [INSERT DATE 60 DAYS AFTER 

PUBLICATION IN THE FEDERAL REGISTER]. 

List of Subjects 

40 CFR Part 63 

Administrative practice and procedure, Air pollution 

control, Hazardous substances, Incorporation by reference, 

Intergovernmental relations, Reporting and recordkeeping 

requirements. 

Dated: [insert date] 

Lisa P. Jackson, 

Administrator. 
140 

For the reasons stated in the preamble, title 40, chapter I, 

part 63 of the Code of Federal Regulations is amended as 

follows: 

PART 63--[AMENDED]

1. The authority citation for part 63 continues to read as 

follows: 

Authority: 42 U.S.C. 7401, et seq. 

Subpart A--[amended] 

2. Section 63.6590 is amended by revising paragraphs 

(b)(1) and (3) to read as follows: 

§63.6590 What parts of my plant does this subpart cover?

* * * * * 

(b) * * * 

(1) An affected source which meets either of the criteria 

in paragraph (b)(1)(i) through (ii) of this section does not 

have to meet the requirements of this subpart and of subpart A 

of this part except for the initial notification requirements of 

§63.6645(f). 

* * * * * 

(3) A stationary RICE which is an existing spark ignition 

4 stroke rich burn (4SRB) stationary RICE located at an area 

source of HAP emissions; an existing spark ignition 4SRB 

stationary RICE with a site rating of less than or equal to 500 

brake HP located at a major source of HAP emissions; an existing 
141 

spark ignition 2 stroke lean burn (2SLB) stationary RICE; an 

existing spark ignition 4 stroke lean burn (4SLB) stationary 

RICE; an existing compression ignition emergency stationary RICE 

with a site rating of more than 500 brake HP located at a major 

source of HAP emissions; an existing spark ignition emergency or 

limited use stationary RICE; an existing limited use stationary 

RICE with a site rating of more than 500 brake HP located at a 

major source of HAP emissions; an existing stationary RICE that 

combusts landfill gas or digester gas equivalent to 10 percent 

or more of the gross heat input on an annual basis; or an 

existing stationary residential, commercial, or institutional 

emergency stationary RICE located at an area source of HAP 

emissions, does not have to meet the requirements of this 

subpart and of subpart A of this part. No initial notification 

is necessary. 

* * * * * 

3. 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?

(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 
142 

limitations and operating limitations 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 and operating limitations no 

later than [INSERT DATE 3 YEARS FROM THE EFFECTIVE DATE OF THE 

RULE]. 

* * * * * 

4. Section 63.6600 is amended by adding an introductory 

paragraph, revising paragraph (c) and adding paragraph (d) to 

read as follows: 

§63.6600 What emission limitations and operating limitations 

must I meet if I own or operate a stationary RICE with a site 

rating of more than 500 brake HP located at a major source of 

HAP emissions?

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. 

* * * * * 
143 

(c) If you own or operate any of the following stationary 

RICE with a site rating of more than 500 brake HP located at a 

major source of HAP emissions, you do not need to comply with 

the emission limitations in Tables 1a, 2a, 2c, and 2d to this 

subpart or operating limitations in Tables 1b and 2b to this 

subpart: an existing 2SLB stationary RICE; an existing 4SLB 

stationary RICE; a stationary RICE that combusts landfill gas or 

digester gas equivalent to 10 percent or more of the gross heat 

input on an annual basis; an emergency stationary RICE; or a 

limited use stationary RICE. 

(d) If you own or operate an existing non-emergency 

stationary CI RICE with a site rating of more than 500 brake HP 

located at a major source of HAP emissions, you must comply with 

the emission limitations in Table 2c to this subpart and the 

operating limitations in Table 2b to this subpart which apply to 

you. 

 5. Section 63.6601 is amended by adding a sentence at the 

beginning of the section to read as follows: 

§63.6601 What emission limitations must I meet if I own or 

operate a 4SLB stationary RICE with a site rating of greater 

than or equal to 250 brake HP and less than 500 brake HP located 

at a major source of HAP emissions? 
144 

* * * 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. 

* * * * * 

 6. Section 63.6602 is added to read as follows: 

§63.6602 What emission limitations must I meet if I own or 

operate an existing stationary CI 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 CI 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 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. 

 7. Section 63.6603 is added to read as follows: 

§63.6603 What emission limitations and operating limitations 

must I meet if I own or operate an existing stationary CI RICE 

located at an area source of HAP emissions? 

Compliance with the numerical emission limitations 

established in this subpart is based on the results of testing 
145 

the average of three 1-hour runs using the testing requirements 

and procedures in §63.6620 and Table 4 to this subpart. 

(a) If you own or operate an existing stationary CI RICE 

located at an area source of HAP emissions, you must comply with 

the requirements in Table 2d to this subpart and the operating 

limitations in Table 2b to this subpart which apply to you. 

(b) If you own or operate an existing stationary nonemergency CI RICE greater than 300 HP located at area sources in 

areas of Alaska not accessible by the Federal Aid Highway System 

(FAHS) you do not have to meet the numerical CO emission 

limitationsstandards specified in Table 2d to this subpart. 

Existing stationary non-emergency CI RICE greater than 300 HP 

located at area sources in areas of Alaska not accessible by the 

FAHS must meet the management practices that are shown for 

stationary non-emergency CI RICE less than or equal to 300 HP in 

Table 2d to this subpart. 

 8. Section 63.6604 is added 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 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. 
146 

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 not accessible by 

the FAHS are exempt from the requirements of this section. 

 9. Section 63.6605 is amended by revising paragraphs (a) 

and (b) to read as follows: 

§63.6605 What are my general requirements for complying with 

this subpart?

 (a) You must be in compliance with the emission limitations 

and operating limitations in this subpart that apply to you at 

all times. 

 (b) At all times you must operate and maintain any affected 

source, including associated air pollution control equipment and 

monitoring equipment, in a manner consistent with safety and 

good air pollution control practices for minimizing emissions. 

The general duty to minimize emissions does not require you to 

make any further efforts to reduce emissions if levels required 

by this standard have been achieved. Determination of whether 

such operation and maintenance procedures are being used will be 

based on information available to the Administrator which may 

include, but is not limited to, monitoring results, review of 

operation and maintenance procedures, review of operation and 

maintenance records, and inspection of the source. 

* * * * * 
147 

10. Section 63.6612 is added to read as follows: 

§63.6612 By what date must I conduct the initial performance 

tests or other initial compliance demonstrations if I own or 

operate an existing stationary 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 RICE located at an area 

source of HAP emissions?

If you own or operate an existing CI stationary 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 are subject to 

the requirements of this section. 

(a) You must conduct any initial performance test or other 

initial compliance demonstration according to Tables 4 and 5 to 

this subpart that apply to you within 180 days after the 

compliance date that is specified for your stationary RICE in 

§63.6595 and according to the provisions in §63.7(a)(2). 

(b) An owner or operator is not required to conduct an 

initial performance test on a unit for which a performance test 

has been previously conducted, but the test must meet all of the 

conditions described in paragraphs (b)(1) through (4) of this 

section. 
148 

(1) The test must have been conducted using the same 

methods specified in this subpart, and these methods must have 

been followed correctly. 

(2) The test must not be older than 2 years. 

(3) The test must be reviewed and accepted by the 

Administrator. 

(4) Either no process or equipment changes must have been 

made since the test was performed, or the owner or operator must 

be able to demonstrate that the results of the performance test, 

with or without adjustments, reliably demonstrate compliance 

despite process or equipment changes. 

11. Section 63.6620 is amended by revising paragraphs (b) 

and (c) 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 

startup 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. 

 (c) [Reserved] 
149 

* * * * * 

12. Section 63.6625 is amended: 

(a) By revising section title; 

(b) By adding paragraph (e); 

(c) By adding paragraph (f); 

(d) By adding paragraph (g); 

(e) By adding paragraph (h); and 

(f) By adding paragraph (i); and

(g) By adding paragraph (j) to read as follows: 

§63.6625 What are my monitoring, installation, collection,

operation, and maintenance requirements?

* * * * * 

 (e) If you own or operate an existing stationary RICE with 

a site rating of less than 100 brake HP located at a major 

source of HAP emissions, an existing stationary emergency RICE, 

or an existing stationary RICE located at an area source of HAP 

emissions not subject to any numerical emission standards shown 

in Table 2d to this subpart, you must operate and maintain the 

stationary RICE and after-treatment control device (if any) 

according to the manufacturer’s emission-related written 

instructions or develop 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. 
150 

(f) If you own or operate an existing emergency stationary 

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 

emergency stationary RICE located at an area source of HAP 

emissions, you must install a non-resettable hour meter if one 

is not already installed. 

(g) If you own or operate an existing non-emergency CI 

engine greater than or equal to 300 HP that is not equipped with 

a closed crankcase ventilation system, you must either; 

(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. 

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 not accessible by the 

FAHS do not have to meet the requirements of paragraph (g) in 

this section. 
151 

(h) If you operate a new or existing stationary engine, 

you must minimize the engine’s time spent at idle during startup 

and minimize the engine’s startup time to a period needed for 

appropriate and safe loading of the engine, not to exceed 30 

minutes, after which time the non-startup emission standards 

applicable to all times other than startup in Tables 1a, 2a, 2c, 

and 2d to this subpartlimitations apply. 

(i) If you own or operate a stationary engine that is 

subject to the work, operation or management practices in items 

1, 2, or 4 of Table 2c to this subpart or in items 1 or 4 of 

Table 2d to this subpart, you have the option of utilizing an 

oil analysis program in order to extend the specified oil change 

requirement in Tables 2c and 2d to this subpart. The oil 

analysis must be performed at the same frequency specified for 

changing the oil in Table 2c or 2d to this subpart. The 

analysis program must at a minimum analyze the following three 

parameters: Total Base Number, viscosity, and percent water 

content. The condemning limits for these parameters are as 

follows: Total Base Number is less than 30 percent of the Total 

Base 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 
152 

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

must change the oil before the next startup of the engine, or 

before continuing to use the engine if the engine was not shut 

down during the oil analysis.. 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. 

(j) If you own or operate a stationary engine at a major 

source that is subject to the work practices or operation 

standards in Table 2c or 2d to this subpart or paragraphs (h) or 

(i) of this section, you have the option to petition the 

Administrator pursuant to §63.6(g)for approval of alternative 

work practices or operation standards. If you own or operate a 

stationary engine at an area source that is subject to the 

management practices in Table 2c or 2d to this subpart or 

paragraphs (h) or (i) of this section, you have the option to 

work with state permitting authorities pursuant to 40 CFR 

subpart E for approval of alternative management practices. Any 

alternative work, operation or management practices must be at 

least as stringent as those specified in Tables 2c and 2d to 

this subpart or paragraphs (h) or (i) of this section, as 

appropriate. 

13. Section 63.6640 is amended by: 

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153 

(a) Revising paragraph (a); 

(b) Revising paragraph (b); 

(c) Revising paragraph (d); 

(d) Revising paragraph (e); and 

(e) Adding paragraph (f) to read as follows: 

§63.6640 How do I demonstrate continuous compliance with the 

emission limitations and operating limitations?

(a) You must demonstrate continuous compliance with each 

emission limitation and operating limitation 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. 

(b) You must report each instance in which you did not 

meet each emission limitation or operating limitation in Tables 

1a and 1b, Tables 2a and 2b, Table 2c, and Table 2d to this 

subpart that apply to you. These instances are deviations from 

the emission and operating limitations in this subpart. These 

deviations must be reported according to the requirements in 

§63.6650. If you change your catalyst, you must reestablish the 

values of the operating parameters measured during the initial 

performance test. When you reestablish the values of your 

operating parameters, you must also conduct a performance test 

to demonstrate that you are meeting the required emission 

limitation applicable to your stationary RICE. 
154 

* * * * * 

(d) For new, reconstructed, and rebuilt stationary RICE, 

deviations from the emission or operating limitations that occur 

during the first 200 hours of operation from engine startup 

(engine burn-in period) are not violations. Rebuilt stationary 

RICE means a stationary RICE that has been rebuilt as that term 

is defined in 40 CFR §94.11(a). 

(e) You must also report each instance in which you did 

not meet the requirements in Table 8 to this subpart that apply 

to you. If you own or operate a new or reconstructed stationary 

RICE with a site rating of less than or equal to 500 brake HP 

located at a major source of HAP emissions (except new or 

reconstructed 4SLB engines greater than or equal to 250 and less 

than or equal to 500 brake HP), a new or reconstructed 

stationary RICE located at an area source of HAP emissions, or 

any of the following RICE with a site rating of more than 500 

brake HP located at a major source of HAP emissions, you do not 

need to comply with the requirements in Table 8 to this subpart: 

An existing 2SLB stationary RICE, an existing 4SLB stationary 

RICE, an existing emergency stationary RICE, an existing limited 

use stationary RICE, or an existing stationary RICE which fires 

landfill gas or digester gas equivalent to 10 percent or more of 

the gross heat input on an annual basis. If you own or operate 

any of the following RICE with a site rating of more than 500 
155 

brake HP located at a major source of HAP emissions, you do not 

need to comply with the requirements in Table 8 to this subpart, 

except for the initial notification requirements: a new or 

reconstructed stationary RICE that combusts landfill gas or 

digester gas equivalent to 10 percent or more of the gross heat 

input on an annual basis, a new or reconstructed emergency 

stationary RICE, or a new or reconstructed limited use 

stationary RICE. 

(f) If you own or operate an existing emergency stationary 

RICE with a site rating of less than or equal to 500 brake HP 

located at a major source of HAP emissions, a new emergency 

stationary RICE with a site rating of more than 500 brake HP 

located at a major source of HAP emissions that was installed on 

or after June 12, 2006, or an existing emergency stationary RICE 

located at an area source of HAP emissions, you must operate the 

engine according to the conditions described in paragraphs 

(f)(1) through (4) of this section. 

(1) For owners and operators of emergency engines, any 

operation other than emergency operation, maintenance and 

testing, and operation in non-emergency situations for 50 hours 

per year, as permitted in this section, is prohibited. 

(2) There is no time limit on the use of emergency 

stationary RICE in emergency situations. 
156 

(3) You may operate your emergency stationary RICE for the 

purpose of maintenance checks and readiness testing, provided 

that the tests are recommended by Federal, State or local 

government, the manufacturer, the vendor, or the insurance 

company associated with the engine. Maintenance checks and 

readiness testing of such units is limited to 100 hours per 

year. 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 year. 

(4) You may operate your emergency stationary RICE up to 

50 hours per year in non-emergency situations, but those 50 

hours are counted towards the 100 hours per year provided for 

maintenance and testing. The 50 hours per year for nonemergency situations cannot be used for peak shaving or to 

generate income for a facility to supply power to an electric 

grid or otherwise supply power as part of a financial 

arrangement with another entity; except that owners and 

operators may operate the emergency engine for a maximum of 15 

hours per year as part of a demand response program if the 

regional transmission organization or equivalent balancing 

authority and transmission operator has determined there are 
157 

emergency conditions that could lead to a potential electrical 

blackout, such as unusually low frequency, equipment overload, 

capacity or energy deficiency, or unacceptable voltage level. 

The engine may not be operated for more than 30 minutes prior to 

the time when the emergency condition is expected to occur, and 

the engine operation must be terminated immediately after the 

facility is notified that the emergency condition is no longer 

imminent. The 15 hours per year of demand response operation 

are counted as part of the 50 hours of operation per year 

provided for non-emergency situations. The supply of emergency 

power to another entity or entities pursuant to financial 

arrangement is not limited by this paragraph (f)(4), as long as 

the power provided by the financial arrangement is limited to 

emergency power. 

 14. Section 63.6645 is amended by revising paragraph (a) 

to read as follows: 

63.6645 What notifications must I submit and when?

(a) You must submit all of the notifications in §§63.7(b) 

and (c), 63.8(e), (f)(4) and (f)(6), 63.9(b) through (e), and 

(g) and (h) that apply to you by the dates specified if you own 

or operate any of the following; 

 (1) 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. 
158 

 (2) An existing stationary CI RICE located at an area 

source of HAP emissions. 

 (3) A stationary RICE with a site rating of more than 500 

brake HP located at a major source of HAP emissions. 

 (4) A new or reconstructed 4SLB stationary RICE with a 

site rating of greater than or equal to 250 HP located at a 

major source of HAP emissions. 

 (5) This requirement does not apply if you own or operate 

an existing stationary CI RICE less than 100 HP, an existing 

stationary emergency CI RICE, or an existing stationary CI RICE 

that is not subject to any numerical emission standards. 

* * * * * 

 15. Section 63.665063.6655 is amended by revising 

paragraph (c)(4)adding paragraphs (e) and (f) to read as 

follows: 

63.6650 What reports must I submit and when?

* * * * *

(c) * * *

(4) If you had a malfunction during the reporting period, 

the compliance report must include the number, duration, and a 

brief description for each type of malfunction which occurred 

during the reporting period and which caused or may have caused 

any applicable emission limitation to be exceeded. The report 

must also include a description of actions taken by an owner or 

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159 

operator during a malfunction of an affected source to minimize 

emissions in accordance with §63.6605(b), including actions 

taken to correct a malfunction.

* * * * *

16. Section 63.6655 is amended by: 

(a) Revising paragraph (a) introductory text;

(b) Revising paragraph (a)(2);

(c) Adding paragraph (a)(4);

(d) Adding paragraph (a)(5); 

(e) Adding paragraph (e); and 

(f) Adding paragraph (f) to read as follows:

§63.6655 What records must I keep?

* * * * * 

 (a) If you must comply with the emission and operating 

limitations, you must keep the records described in paragraphs 

(a)(1) through (a)(5), (b)(1) through (b)(3) and (c) of this 

section.

 (1) * * *

 (2) Records of the occurrence and duration of each 

malfunction of operation (i.e., process equipment) or the air 

pollution control and monitoring equipment.

 (3) * * *

 (4) Records of all required maintenance performed on the 

air pollution control and monitoring equipment.

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160 

 (5) Records of actions taken during periods of malfunction 

to minimize emissions in accordance with §63.6605(b), including 

corrective actions to restore malfunctioning process and air 

pollution control and monitoring equipment to its normal or 

usual manner of operation.

* * * * * 

(e) You must keep records of the maintenance conducted on 

the stationary RICE in order to demonstrate that you operated 

and maintained the stationary RICE and after-treatment control 

device (if any) according to your own maintenance plan if you 

own or operate any of the following stationary RICE; 

 (1) An existing stationary CI RICE with a site rating of 

less than 100 brake HP located at a major source of HAP 

emissions. 

 (2) An existing stationary emergency CI RICE. 

 (3) An existing stationary CI RICE located at an area 

source of HAP emissions subject to management practices as shown 

in Table 2d to this subpart. 

(f) If you own or operate any of the stationary RICE in 

paragraphs (f)(1) or (2) of this section, you must keep records 

of the hours of operation of the engine that is recorded through 

the non-resettable hour meter. The owner or operator must 

document how many hours are spent for emergency operation, 

including what classified the operation as emergency and how 
161 

many hours are spent for non-emergency operation. If the 

engines are used for demand response operation, the owner or 

operator must keep records of the notification of the emergency 

situation, and the time the engine was operated as part of 

demand response. 

(1) An existing emergency stationary CI RICE with a site 

rating of less than or equal to 500 brake HP located at a major 

source of HAP emissions that does not meet the standards 

applicable to non-emergency engines. 

(2) An existing emergency stationary CI RICE located at an 

area source of HAP emissions that does not meet the standards 

applicable to non-emergency engines. 

17.16. Section 63.6660 is amended by revising paragraph 

(c) to read as follows: 

§63.6660 In what form and how long must I keep my records?

* * * * * 

 (c) You must keep each record readily accessible in hard 

copy or electronic form for at least 5 years after the date of 

each occurrence, measurement, maintenance, corrective action, 

report, or record, according to §63.10(b)(1). 

18.17. Section 63.6665 is revised to read as follows: 

§63.6665 What parts of the General Provisions apply to me?

Table 8 to this subpart shows which parts of the General 

Provisions in §§63.1 through 63.15 apply to you. If you own or 
162 

operate a new or reconstructed stationary RICE with a site 

rating of less than or equal to 500 brake HP located at a major 

source of HAP emissions (except new or reconstructed 4SLB 

engines greater than or equal to 250 and less than or equal to 

500 brake HP), a new or reconstructed stationary RICE located at 

an area source of HAP emissions, or any of the following RICE 

with a site rating of more than 500 brake HP located at a major 

source of HAP emissions, you do not need to comply with any of 

the requirements of the General Provisions specified in Table 

8:: An existing 2SLB stationary RICE, an existing 4SLB 

stationary RICE, an existing stationary RICE that combusts 

landfill or digester gas equivalent to 10 percent or more of the 

gross heat input on an annual basis, an existing emergency 

stationary RICE, or an existing limited use stationary RICE. If 

you own or operate any of the following RICE with a site rating 

of more than 500 brake HP located at a major source of HAP 

emissions, you do not need to comply with the requirements in 

the General Provisions specified in Table 8 except for the 

initial notification requirements: A new stationary RICE that 

combusts landfill gas or digester gas equivalent to 10 percent 

or more of the gross heat input on an annual basis, a new 

emergency stationary RICE, or a new limited use stationary RICE. 

19.18. Section 63.6675 is amended: 

 (a) By revising the definition of Diesel fuel; 
163 

 (b) By revising the definition of Emergency stationary 

RICE; 

 (c) By adding the definition of Black start engine; 

 (d) By adding the definition of Engine startup; and 

 (e) By adding the definition of 

Residential/commercial/institutional emergency stationary RICE, 

in alphabetical order, to read as follows: 

§63.6675 What definitions apply to this subpart?

* * * * * 

Black start engine means an engine whose only purpose is to 

start up a combustion turbine. 

* * * * * 

Diesel fuel means any liquid obtained from the distillation 

of petroleum with a boiling point of approximately 150 to 360 

degrees Celsius. One commonly used form is fuel oil number 2. 

Diesel fuel also includes any non-distillate fuel with 

comparable physical and chemical properties (e.g. biodiesel) 

that is suitable for use in compression ignition engines. 

* * * * * 

Emergency stationary RICE means any stationary internal 

combustion engine whose operation is limited to emergency 

situations and required testing and maintenance. Examples 

include stationary ICE used to produce power for critical 

networks or equipment (including power supplied to portions of a 
164 

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. Stationary CI ICE used for 

peak shaving are not considered emergency stationary ICE. 

Stationary CI ICE used to supply power to an electric grid or 

that supply non-emergency power as part of a financial 

arrangement with another entity are not considered to be 

emergency engines, except as permitted under §63.6640(f). 

Emergency stationary RICE with a site-rating of more than 500 

brake HP located at a major source of HAP emissions that were 

installed prior to June 12, 2006, may be operated for the 

purpose of maintenance checks and readiness testing, provided 

that the tests are recommended by the manufacturer, the vendor, 

or the insurance company associated with the engine. Required 

testing of such units should be minimized, but there is no time 

limit on the use of emergency stationary RICE in emergency 

situations and for routine testing and maintenance. Emergency 

stationary RICE with a site-rating of more than 500 brake HP 

located at a major source of HAP emissions that were installed 

prior to June 12, 2006, may also operate an additional 50 hours 

per year in non-emergency situations. All other emergency 

stationary RICE must comply with the requirements specified in 

§63.6640(f). 
165 

 Engine startup means the time from initial start until 

applied load and engine and associated equipment reaches steady 

state or normal operation. For stationary engine with catalytic 

controls, engine startup means the time from initial start until 

applied load and engine and associated equipment, including the 

catalyst, reaches steady state or normal operation. 

* * * * * 

Residential/commercial/institutional emergency stationary 

RICE means an emergency stationary RICE used in residential 

establishments such as homes or residences, commercial 

establishments such as office buildings, hotels, or stores, or 

institutional establishments such as medical centers, research 

centers, and institutions of higher education. 

20.19. Table 1a to Subpart ZZZZ of Part 63 is amended to 

read as follows: 

Table 1a to Subpart ZZZZ of Part 63. Emission Limitations for 

Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary 

RICE >500 HP Located at a Major Source of HAP Emissions 

As stated in §§63.6600 and 63.6640, you must comply with the 

following emission limitations for existing, new and 

reconstructed 4SRB stationary RICE at 100 percent load plus or 

minus 10 percent: 

For each... You must meet the 

following emission 

limitation, except 

during periods of 

startup... 

During periods of 

startup you must... 

1. 4SRB a. Reduce Minimize the engine’s 
166 

stationary 

RICE 

formaldehyde 

emissions by 76 

percent or more. If 

you commenced 

construction or 

reconstruction 

between December 19, 

2002 and June 15, 

2004, you may reduce 

formaldehyde 

emissions by 75 

percent or more until 

June 15, 2007 or 

b. Limit the 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust to 350 ppbvd 

or less at 15 percent 

O2. 

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 nonstartup emission 

limitations apply.1

1 Sources can have the option to petition the Administrator 

pursuant to the requirements of 40 CFR 63.6(g) for alternative 

work practices. Any petition must be based on specific 

factual information indicating the reason that an alternative 

work practice is at least as stringent as those specified in 

Table 1a of this subpart.

21.20. Table 2a to Subpart ZZZZ of Part 63 is amended to 

read as follows: 

Table 2a to Subpart ZZZZ of Part 63. Emission Limitations for 

New and Reconstructed 2SLB and Compression Ignition Stationary 

RICE >500 HP and New and Reconstructed 4SLB Stationary RICE ≥250 

HP Located at a Major Source of HAP Emissions 

As stated in §§63.6600 and 63.6640, you must comply with the 

following emission limitations for new and reconstructed lean 

burn and new and reconstructed compression ignition stationary 

RICE at 100 percent load plus or minus 10 percent: 

For each. . . You must meet the 

following emission 

limitation, except 

during periods of 

During periods of 

startup you must... 
167 

startup. . . 

1. 2SLB 

stationary RICE 

a. Reduce CO 

emissions by 58 

percent or more; or 

b. Limit 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust to 12 ppmvd 

or less at 15 

percent O2. If you 

commenced 

construction or 

reconstruction 

between December 

19, 2002 and June 

15, 2004, you may 

limit concentration 

of formaldehyde to 

17 ppmvd or less at 

15 percent O2 until 

June 15, 2007. 

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.1

2. 4SLB 

stationary RICE 

a. Reduce CO 

emissions by 93 

percent or more; or 

b. Limit 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust to 14 ppmvd 

or less at 15 

percent O2. 

3. CI 

stationary RICE

a. Reduce CO 

emissions by 70 

percent or more; or 

b. Limit 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust to 580 

ppbvd or less at 15 

percent O2. 1 Sources can have the option to petition the Administrator 
168 

pursuant to the requirements of 40 CFR 63.6(g) for alternative 

work practices. Any petition must be based on specific 

factual information indicating the reason that an alternative 

work practice is at least as stringent as those specified in 

Table 2a of this subpart.

22.21. Table 2b to Subpart ZZZZ of Part 63 is amended to 

read as follows: 

Table 2b to Subpart ZZZZ of Part 63. Operating Limitations for 

New and Reconstructed 2SLB and Compression Ignition Stationary 

RICE >500 HP Located at a Major Source of HAP Emissions, 

Existing Non-Emergency Compression Ignition Stationary RICE >500 

HP, and New and Reconstructed 4SLB Burn Stationary RICE ≥250 HP 

Located at a Major Source of HAP Emissions 

As stated in §§63.6600, 63.6601, 63.6630, and 63.6640, you must 

comply with the following operating limitations for new and 

reconstructed lean burn and existing, new and reconstructed 

compression ignition stationary RICE: 

For each... You must meet the following 

operating limitation...

1. 2SLB and 4SLB stationary 

RICE and CI stationary RICE 

complying with the requirement 

to reduce CO emissions and 

using an oxidation catalyst; or 

2SLB and 4SLB stationary RICE 

and CI stationary RICE 

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
169 

2. 2SLB and 4SLB stationary 

RICE and CI stationary RICE 

complying with the requirement 

to reduce CO emissions and not 

using an oxidation catalyst; or 

2SLB and 4SLB stationary RICE 

and CI stationary RICE 

complying with the requirement 

to limit the concentration of 

formaldehyde in the stationary 

RICE exhaust and not using an 

oxidation catalyst 

comply with any operating 

limitations approved by the 

Administrator. 

1

Sources canmay petition the Administrator pursuant to the 

requirements of 40 CFR 63.8(g) for a different temperature 

range.range; the petition must provide specific factual 

information to demonstrate that it is operationally necessary 

and appropriate to operate below the temperature range specified 

in Table 2b of this subpart.

23.22. Subpart ZZZZ of Part 63 is amended by adding Tables 

2c and 2d to Subpart ZZZZ of Part 63 to read as follows: 

Table 2c to Subpart ZZZZ of Part 63. Requirements for Existing 

Compression Ignition Stationary Rice Located at Major Sources of 

HAP Emissions 

As stated in §§63.6600 and 63.6640, you must comply with the 

following requirements for existing compression ignition 

stationary RICE: 

For each... You must meet the 

following requirement, 

except during periods of 

startup... 

During periods of 

startup you must... 
170 

1. Emergency CI 

and black start 

CI.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; 

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 CI 

<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; 

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 

RICE 100<HP<300 

HP. 

Limit concentration of CO 

in the stationary RICE 

exhaust to 230 ppmvd or 

less at 15 percent O2. 

4. NonEmergency, nonblack start CI 

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 

CI>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. 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 
171 

work practice requirements on the schedule required in Table 2c 

of this subpart, or if performing the work practice on the 

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 that defined the unacceptable risk.

2

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 2c of this subpart. 

3 Sources can have the option to petition the Administrator 

pursuant to the requirements of 40 CFR 63.6(g) for approval of 

alternative work practices. Any petition must be based on 

specific factual information indicating the reason that an 

alternative work practice is at least as stringent as those 

specified in Table 2c of this subpart.

Table 2d to Subpart ZZZZ of Part 63. Requirements for Existing 

Compression Ignition Stationary RICE Located at Area Sources of 

HAP Emissions 

As stated in §§63.6600 and 63.6640, you must comply with the 

following emission and operating limitations for existing 

compression ignition stationary RICE: 

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 

<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; 

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.2

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172 

c. Inspect all 

hoses and belts 

every 500 hours of 

operation or 

annually, whichever 

comes first, and 

replace as 

necessary.2

2. Non-Emergency, 

non-black start CI 

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 

>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. 
173 

4. Emergency CI 

and black start 

CI.2

CI.3

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 

c. Inspect all 

hoses and belts 

every 500 hours of 

operation or 

annually, whichever 

comes first, and 

replace as 

necessary.2

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. 

22 Sources have the option to work with state permitting

authorities pursuant to 40 CFR subpart E for approval of 

alternative management practices. The alternative management

practices must be at least as stringent as those specified in 

Table 2d of this subpart. 3 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 that 

defined the unacceptable risk.has abated.

 24. 23. Table 3 to Subpart ZZZZ of Part 63 is amended to 

read 

as follows: 
174 

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: 

For each... Complying with the 

requirement to... 

You must...

1. 2SLB and 4SLB 

stationary RICE 

with a brake 

horsepower >500 

located at major 

sources and new or 

reconstructed CI 

stationary RICE 

with a brake 

horsepower >500 

located at major 

sources. 

Reduce CO 

emissions and not 

using a CEMS 

Conduct subsequent 

performance tests 

semiannually1

. 

2. 4SRB stationary 

RICE with a brake 

horsepower ≥5,000 

located at major 

sources. 

Reduce 

formaldehyde 

emissions 

Conduct subsequent 

performance tests 

semiannually1

. 

3. Stationary RICE 

with a brake 

horsepower >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 

with a brake 

horsepower >500. 

Limit or reduce CO 

or formaldehyde 

emissions 

Conduct subsequent 

performance tests 

every 8,760 hrs or 

3 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 

compliance with the CO or formaldehyde emission limitation, or 

you deviate from any of your operating limitations, you must 

resume semiannual performance tests. 
175 

25. Table 4 to Subpart ZZZZ of Part 63 is amended 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 existing sources: 

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) 

portable 

CO and 

O2 

analyzer 

(a) using 

ASTM D6522-

00 (2005)a

(incorporated by 

reference, 

see §63.14). 

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) 

portable 

CO and 

O2 

analyzer 

(a) using 

ASTM D6522-

00 (2005)a,b

(incorporated by 

reference, 

see §63.14) 

or Method 10 

of 40 CFR 

appendix A. 

The CO 

concentration must be 
176 

at 15 

percent O2, 

dry basis. 

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 concentration must be 

made at the 

same time as 

the 

measurements 

for 

formaldehyde 

concentratio

n. 

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 

concentration. 
177 

iv. 

measure 

formaldehyde at 

the inlet 

and the 

outlet of 

the 

control 

device 

(1) 

Method 

320 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. 

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 

(1) 

Method 3 

or 3A or 

3B of 40 

CFR part 

60, 

appendix 

A, or 

(a) 

measurements 

to determine 

O2 concentration must be 

made at the 

same time 

and location 
178 

exhaust 

at the 

sampling 

port 

location; 

and 

ASTM 

Method 

D6522-

00(2005)

. 

as the 

measurements 

for 

formaldehyde 

concentration. 

iii. 

measure 

moisture 

content 

of the 

stationary RICE 

exhaust 

at the 

sampling 

port 

location; 

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 

concentratio

n. 

iv. 

measure 

formaldehyde at 

the 

exhaust 

of the 

stationary RICE; 

or 

(1) 

Method 

320 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 

(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. 
179 

less 

than or 

equal to 

130. 

v. 

measure 

CO at the 

exhaust 

of the 

stationary RICE. 

(1) 

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 

D6348-

03. 

(a) CO 

concentratio

n must be at 

15 percent 

O2, dry 

basis. 

Results of 

this test 

consist of 

the average 

of the three 

1-hour 

longer runs. 

v. 

measure 

CO at the 

exhaust 

of the 

stationary RICE. 

(1) 

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 

D6348-

03. 

(a) CO 

concentratio

n must be at 

15 percent 

O2, dry 

basis. 

Results of 

this test 

consist of 

the average 

of the three 

1-hour 

longer runs. 

a

You may also use Methods 3A and 10 as options to ASTM-D6522-00 

(2005). You 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, 
180 

PA 19428-2959, or University Microfilms International, 300 North 

Zeeb Road, Ann Arbor, MI 48106. 

b

You may also use Method 320 of 40 CFR part 63, appendix A, or 

ASTM D6348-03. 

c

You 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. 

25. Table 5 to Subpart ZZZZ of Part 63 is amended 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 . . . 
181 

1. 2SLB and 4SLB 

stationary RICE 

>500 HP located at 

a major source and 

new or 

reconstructed CI 

stationary RICE 

>500 HP located at 

a major source. 

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. 

2. 2SLB and 4SLB 

stationary RICE 

>500 HP located at 

a major source and 

new or 

reconstructed CI 

stationary RICE 

>500 HP located at 

a major source. 

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 
182 

approved operating 

parameters (if any) 

during the initial 

performance test. 

3. 2SLB and 4SLB 

stationary RICE 

>500 HP located at 

a major source and 

new or 

reconstructed CI 

stationary RICE 

>500 HP located at 

a major source. 

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. 

4. 4SRB stationary 

RICE >500 HP 

located at a major 

source. 

a. Reduce 

formaldehyde 

emissions and using 

NSCR 

i. The average 

reduction of 

emissions of 

formaldehyde 

determined from the 
183 

initial performance 

test is equal to or 

greater than the 

required 

formaldehyde 

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. 

5. 4SRB stationary 

RICE >500 HP 

located at a major 

source. 

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 

the requirements in 

§63.6625(b); and 
184 

iii. You have 

recorded the 

approved operating 

parameters (if any) 

during the initial 

performance test. 

6. Stationary RICE 

>500 HP located at 

a major source. 

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. 

7. Stationary RICE 

>500 HP located at 

a major source. 

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 

limitation; and 
185 

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. 

8. Existing 

stationary nonemergency RICE 

≥100 HP located at 

a major source, 

existing nonemergency CI 

stationary RICE 

>500 HP, and 

existing 

stationary nonemergency RICE 

≥100 HP located at 

an area source. 

a. Reduce CO or 

formaldehyde 

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. 

9. Existing 

stationary nonemergency RICE 

≥100 HP located at 

a major source, 

existing nonemergency CI 

stationary RICE 

>500 HP, and 

existing 

stationary nonemergency RICE 

≥100 HP located at 

an area source. 

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. 
186 

26. Table 6 to Subpart ZZZZ of Part 63 is amended to read 

as follows: 

Table 6 to Subpart ZZZZ of Part 63. Continuous Compliance With 

Emission Limitations and Operating Limitations 

As stated in §63.6640, you must continuously comply with the 

emissions and operating limitations as required by the 

following: 

For each . . . Complying with the 

requirement to . . 

. 

You must 

demonstrate 

continuous 

compliance by 

. . . 

1. 2SLB and 4SLB 

stationary RICE 

>500 HP located at 

a major source and 

CI stationary RICE 

>500 HP located at 

a major source. 

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 

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 
187 

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. 2SLB and 4SLB 

stationary RICE 

>500 HP located at 

a major source and 

CI stationary RICE 

>500 HP located at 

a major source. 

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 

4-hour rolling 

averages within the 

operating 

limitations for the 

operating 

parameters 

established during 

the performance 

test. 

3. 2SLB and 4SLB 

stationary RICE 

>500 HP located at 

a major source and 

a. Reduce CO 

emissions and using 

a CEMS 

i. Collecting the 

monitoring data 

according to 

§63.6625(a), 
188 

CI stationary RICE 

>500 HP located at 

a major source. 

reducing the 

measurements to 1-

hour averages, 

calculating the 

percent reduction 

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; 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, 

procedure 1. 

4. 4SRB stationary 

RICE >500 HP 

located at a major 

source. 

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 
189 

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. 4SRB stationary 

RICE >500 HP 

located at a major 

source. 

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 

operating 

limitations for the 

operating 

parameters 

established during 

the performance 

test. 

6. 4SRB stationary 

RICE with a brake 

HP ≥5,000 located 

at a major source. 

Reduce formaldehyde 

emissions 

Conducting 

semiannual 

performance tests 

for formaldehyde to 

demonstrate that 

the required 

formaldehyde 

percent reduction 

is achieveda

. 

7. Stationary RICE Limit the i. Conducting 
190 

>500 HP located at 

a major source. 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust and using 

oxidation catalyst 

or NSCR 

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 

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. Stationary RICE 

>500 HP located at 

a major source. 

Limit the 

concentration of 

formaldehyde in the 

stationary RICE 

exhaust and not 

i. Conducting 

semiannual 

performance tests 

for formaldehyde to 

demonstrate that 
191 

using oxidation 

catalyst or NSCR 

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 

operating 

parameters 

established during 

the performance 

test. 

9. Existing 

stationary CI RICE 

not subject to any 

numerical emission 

limitations. 

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 
192 

consistent with 

good air pollution 

control practice 

for minimizing 

emissions. 

11. Existing 

stationary RICE 

>500 HP, except 

4SRB >500 HP 

located at major 

sources. 

a. Reduce CO or 

formaldehyde 

emissions; 

or 

b. Limit the 

concentration of 

formaldehyde or CO

in the stationary 

RICE exhaust. 

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.

a

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 

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 7 to Subpart ZZZZ of Part 63 is amended 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:

You must submit 

a(n)

The report must 

contain . . .

You must submit the 

report . . .

1. Compliance a. If there are no 

deviations from any 

i. Semiannually 

according to the 
193 

report 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 outof-control, as 

specified in 

§63.8(c)(7), a 

statement that 

there were not 

periods during 

which the CMS was 

out-of-control 

during the 

reporting period; 

or

requirements in 

§63.6650(b).

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 outof-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).
194 

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. 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 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

i. Annually, 

according to the 

requirements in 

§63.6650.

b. The operating 

limits provided in 

your federally 

enforceable permit, 

and any deviations 

from these limits; 

and

i. See item 3.a.i.

c. Any problems or 

errors suspected 

with the meters.

i. See item 3.a.i.

28. Table 8 to Subpart ZZZZ of Part 63 is amended to read 

as follows: 

Table 8 to Subpart ZZZZ of Part 63. Applicability of General 

Provisions to Subpart ZZZZ. 

As stated in §63.6665, you must comply with the following 

applicable general provisions. 

 

General 

Provisions 

Subject of Citation Applie

s to 

Subpar

Explanation 
195 

Citation t 

§63.1 General 

applicability of 

the General 

Provisions 

Yes 

§63.2 Definitions Yes Additional terms 

defined in 

§63.6675.

§63.3 Units and 

abbreviations 

Yes 

§63.4 Prohibited 

activities and 

circumvention 

Yes 

§63.5 Construction and 

reconstruction 

Yes 

§63.6(a) Applicability Yes 

§63.6(b)(1)-(4) Compliance dates 

for new and 

reconstructed 

sources 

Yes 

§63.6(b)(5) Notification Yes 

§63.6(b)(6) [Reserved] 

§63.6(b)(7) Compliance dates 

for new and 

reconstructed area 

sources that become 

major sources 

Yes 

§63.6(c)(1)-(2) Compliance dates 

for existing 

sources 

Yes 

§63.6(c)(3)-(4) [Reserved] 

§63.6(c)(5) Compliance dates 

for existing area 

sources that become 

major sources 

Yes 

§63.6(d) [Reserved] 

§63.6(e) Operation and 

maintenance 

No 

§63.6(f)(1) Applicability of 

standards 

No 

§63.6(f)(2) Methods for 

determining 

Yes 
196 

compliance 

§63.6(f)(3) Finding of 

compliance 

Yes 

§63.6(g)(1)-(3) Use of alternate 

standard 

Yes 

§63.6(h) Opacity and visible 

emission standards 

No Subpart ZZZZ does 

not contain 

opacity or 

visible emission 

standards. 

§63.6(i) Compliance 

extension 

procedures and 

criteria 

Yes 

§63.6(j) Presidential 

compliance 

exemption 

Yes 

§63.7(a)(1)-(2) Performance test 

dates 

Yes Subpart ZZZZ 

contains 

performance test 

dates at 

§§63.6610, 

63.6611, and 

63.6612. 

§63.7(a)(3) CAA section 114 

authority 

Yes 

§63.7(b)(1) Notification of 

performance test 

Yes Except that 

§63.7(b)(1) only 

applies as 

specified in 

§63.6645. 

§63.7(b)(2) Notification of 

rescheduling 

Yes Except that 

§63.7(b)(2) only 

applies as 

specified in 

§63.6645. 

§63.7(c) Quality 

assurance/test plan 

Yes Except that 

§63.7(c) only 

applies as 

specified in 

§63.6645. 

§63.7(d) Testing facilities Yes 

§63.7(e)(1) Conditions for 

conducting 

No. Subpart ZZZZ 

specifies 
197 

performance tests conditions for 

conducting 

performance tests 

at §63.6620. 

§63.7(e)(2) Conduct of 

performance tests 

and reduction of 

data 

Yes Subpart ZZZZ 

specifies test 

methods at 

§63.6620. 

§63.7(e)(3) Test run duration Yes 

§63.7(e)(4) Administrator may 

require other 

testing under 

section 114 of the 

CAA 

Yes 

§63.7(f) Alternative test 

method provisions 

Yes 

§63.7(g) Performance test 

data analysis, 

recordkeeping, and 

reporting 

Yes 

§63.7(h) Waiver of tests Yes 

§63.8(a)(1) Applicability of 

monitoring 

requirements 

Yes Subpart ZZZZ 

contains specific 

requirements for 

monitoring at 

§63.6625. 

§63.8(a)(2) Performance 

specifications 

Yes 

§63.8(a)(3) [Reserved] 

§63.8(a)(4) Monitoring for 

control devices 

No 

§63.8(b)(1) Monitoring Yes 

§63.8(b)(2)-(3) Multiple effluents 

and multiple 

monitoring systems 

Yes 

§63.8(c)(1) Monitoring system 

operation and 

maintenance 

Yes 

§63.8(c)(1) 

(i) 

Routine and 

predictable SSM 

Yes 

§63.8(c)(1) 

(ii) 

SSM not in Startup 

Shutdown 

Malfunction Plan 

Yes 

§63.8(c)(1) 

(iii) 

Compliance with 

operation and 

Yes 
198 

maintenance 

requirements 

§63.8(c)(2)-(3) Monitoring system 

installation 

Yes 

§63.8(c)(4) Continuous 

monitoring system 

(CMS) requirements 

Yes Except that 

subpart ZZZZ does 

not require 

Continuous 

Opacity 

Monitoring System 

(COMS). 

§63.8(c)(5) COMS minimum 

procedures 

No Subpart ZZZZ does 

not require COMS. 

§63.8(c)(6)-(8) CMS requirements Yes Except that 

subpart ZZZZ does 

not require COMS. 

§63.8(d) CMS quality control Yes 

§63.8(e) CMS performance 

Evaluation 

Yes Except for 

§63.8(e)(5)(ii), 

which applies to 

COMS. 

Except that 

§63.8(e) only 

applies as 

specified in 

§63.6645. 

§63.8(f)(1)-(5) Alternative 

monitoring 

Method 

Yes Except that 

§63.8(f)(4) only 

applies as 

specified in 

§63.6645. 

§63.8(f)(6) Alternative to 

relative accuracy 

test 

Yes Except that 

§63.8(f)(6) only 

applies as 

specified in 

§63.6645. 

§63.8(g) Data reduction Yes Except that 

provisions for 

COMS are not 

applicable. 

Averaging periods 

for demonstrating 

compliance are 

specified at 

§§63.6635 and 

63.6640. 
199 

§63.9(a) Applicability and 

State delegation of 

notification 

requirements 

Yes 

§63.9(b)(1)-(5) Initial 

notifications 

Yes Except that 

§63.9(b)(3) is 

reserved. 

Except that 

§63.9(b) only 

applies as 

specified in 

§63.6645. 

§63.9(c) Request for 

compliance 

Extension 

Yes Except that 

§63.9(c) only 

applies as 

specified in 

§63.6645. 

§63.9(d) Notification of 

special 

compliance 

requirements for 

new sources 

Yes Except that 

§63.9(d) only 

applies as 

specified in 

§63.6645. 

§63.9(e) Notification of 

performance test 

Yes Except that 

§63.9(e) only 

applies as 

specified in 

§63.6645. 

§63.9(f) Notification of 

visible emission 

(VE)/opacity test 

No Subpart ZZZZ does 

not contain 

opacity or VE 

standards. 

§63.9(g)(1) Notification of 

performance 

evaluation 

Yes Except that 

§63.9(g) only 

applies as 

specified in 

§63.6645. 

§63.9(g)(2) Notification of use 

of COMS data 

No Subpart ZZZZ does 

not contain 

opacity or VE 

standards. 

§63.9(g)(3) Notification that 

criterion for 

alternative to RATA 

is exceeded 

Yes If alternative is 

in use. 

Except that 

§63.9(g) only 

applies as 
200 

specified in 

§63.6645. 

§63.9(h)(1)-(6) Notification of 

compliance status 

Yes Except that 

notifications for 

sources using a 

CEMS are due 30 

days after 

completion of 

performance 

evaluations. 

§63.9(h)(4) is 

reserved. 

Except that 

§63.9(h) only 

applies as 

specified in 

§63.6645. 

§63.9(i) Adjustment of 

submittal deadlines

Yes 

§63.9(j) Change in previous 

information 

Yes 

§63.10(a) Administrative 

provisions for 

record 

keeping/reporting 

Yes 

§63.10(b)(1) Record retention Yes 

§63.10(b)(2) 

(i)-(v) 

Records related to 

SSM 

NoYes

§63.10(b)(2) 

(vi)-(xi) 

Records Yes 

§63.10(b)(2) 

(xii) 

Record when under 

waiver 

Yes 

§63.10(b)(2) 

(xiii) 

Records when using 

alternative to RATA 

Yes For CO standard 

if using RATA 

alternative. 

§63.10(b)(2) 

(xiv) 

Records of 

supporting 

documentation 

Yes 

§63.10(b)(3) Records of 

applicability 

determination 

Yes 

§63.10(c) Additional records 

for sources using 

CEMS 

Yes Except that 

§63.10(c)(2)-(4) 

and (9) are 

reserved. 

§63.10(d)(1) General reporting Yes 
201 

Requirements 

§63.10(d)(2) Report of 

performance test 

results 

Yes 

§63.10(d)(3) Reporting opacity 

or VE 

Observations 

No Subpart ZZZZ does 

not contain 

opacity or VE 

standards. 

§63.10(d)(4) Progress reports Yes

§63.10(d)(5) Startup, shutdown, 

and 

malfunction 

reports 

NoYes

§63.10(e)(1) 

and (2)(i) 

Additional CMS 

Reports 

Yes 

§63.10(e)(2) 

(ii) 

COMS-related report No Subpart ZZZZ does 

not require COMS. 

§63.10(e)(3) Excess emission and 

parameter 

exceedances reports 

Yes Except that 

§63.10(e)(3)(i) 

(C) is reserved. 

§63.10(e)(4) Reporting COMS data No Subpart ZZZZ does 

not require COMS. 

§63.10(f) Waiver for 

recordkeeping/ 

Reporting 

Yes 

§63.11 Flares No 

§63.12 State authority and 

delegations 

Yes 

§63.13 Addresses Yes 

§63.14 Incorporation by 

reference 

Yes 

§63.15 Availability of 

information 

Yes