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 thesethis national 

emission standards for hazardous air pollutants. 
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-

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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 

RegulatoryEconomic 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? 

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

C. What are the final requirements? 

D. What are the operating limitations?Operating Limitation?

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 StandardsLimits

C. ManagementMaintenance 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? estimates?

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?
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 
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 
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 
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 

ignition 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 
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 
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 
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) 

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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 
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 existing, 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 subpartSubpart ZZZZ requirements for: 

existing CInew and reconstructed stationary RICE less than or 

equal to 500 HP located at major sources and existing CInew and 

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reconstructed stationary RICE located at area sources. When the 

subpart ZZZZ regulations were promulgated (see 69 FR 33474, June 

15, 2004), EPA deferred promulgating regulations with respect to 

stationary engines 500 HP or less at major sources until further 

information on the engines could be obtained and analyzed. EPA 

decided to regulate these smaller engines at the same time that 

it regulated engines located at area sources. 

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 

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"which provide 

for the use of generally available control technologies or 

management practices by such sources to reduce emissions of 

hazardous air pollutants.”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 

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 

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 aromatic hydrocarbons, polycyclic organic matter, 

styrene, toluene, and xylene. 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). 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 

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.4

 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 

 

4

 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. 
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 

numerical emission standards are in units of ppmparts per 

million 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 230157 ppmvd CO at 15% O2 

Non-Emergency CI 

300<HP≤500 

4946 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 parts per million (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 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;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 

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;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 usePursuant to the provisions of 

40 CFR 63.6(g), sources may petition the Administrator to 

utilize an oil change analysis program in order to extend the 

specified oil change frequenciesrequirement specified above. 

The analysis program must at a 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 may [insert discussion of 

what engine o/o should do]. If any of the limits below 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 

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

also request that the Administrator approve alternative work 

practices.practice. The alternative maintenance 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 

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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 

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 

4946 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 

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;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;first, and 

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

whichever comes first, and replace as necessary. 

As discussed above for major sources, thesePursuant to the provisions 

of 40 CFR 63.6(g), sources may petition the Administrator to utilize an 

oil analysis program in order to extend the specified oil change 

requirement specified above. Also, pursuant to the provisions of 40 

CFR 63.6(g), 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’’)petition the Administrator for approval of alternative 

managementmaintenance 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 managementmaintenance

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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 with a crankcase open to the atmosphere 

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. 

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 

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 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 longer 

period 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. 

Such alternative work or management practicetime. Any petition
must be demonstrated to be no less stringent than EPA 

promulgated standards.based on specific factual information 

indicating the reason that a longer period is necessary for that 

engine. These requirements will limit the HAP emissions during 

periods of engine startup. 

D. What are the operating limitations?Operating Limitations? 

 In addition to the standards discussed above, EPA is 

finalizing operating limitations for stationary non-emergency CI 

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. 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 

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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?

 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 

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 

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. 

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 

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 

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 

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 

the regulated source category. EPA has found that existing 

emergency engines located at residential, commercial, and 

institutional facilities 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 StandardsLimits

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. Based on comments 

received including the feasibility of being able to measure 
formaldehyde emissions of that magnitude, 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 or equal to 100 HP. 

In the proposed rule, existing stationary CI engines less 

than or equal to 100 HP located at major sources were required 

to meet a 40 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 describedshown in section III.C.Table 1 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 ““Subcategorization and MACT Floor 

Determination for Existing Stationary Non-Emergency CI RICE Less 

Than 100 HP and Existing Stationary Emergency CI RICE LocatedCI 

Reciprocating Internal Combustion Engines 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 

230157 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 

“Subcategorization and MACT Floor Determination for Existing 

Stationary Non-Emergency CI RICE Greater Than or Equal to 100 HP 

LocatedReciprocating Internal Combustion Engines 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 thisreanalyzed the dataset. EPA is finalizing emission 

standards based on additional test data in the MACT floor 

analysis. EPA is alsopoints and 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 

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 4946 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 

describedshown in section III.C.Table 1 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 the memorandum entitled ““Subcategorization and 

MACT Floor Determination for Existing Stationary Non-Emergency 

CI RICE Less Than 100 HP and Existing Stationary Emergency CI 

RICE LocatedCI Reciprocating Internal Combustion Engines 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 GACTsuitable 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 

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. Pursuant to 40 

CFR 63.6(g), sources may petition the Administrator to utilize 

an oil analysis program in order to extend the specified oil 

change requirement. 

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 forPursuant to 40 

CFR 63.6(g), sources to usemay petition the Administrator to 

utilize an oil change analysis program in order 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. If the 

condemning limits provided below are not exceeded, the engine 

owner or operator may [insert discussion of what engine o/o 

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should do]. If any of the limits below 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. 

oil change requirement. Owners and operators of all engines 

subject to management practices also have the option work with 

state permitting authorities pursuant to EPA’s regulations at 40 

CFR subpart E63.6(g) to petition the Administrator 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 shutting the engine down would otherwise pose 

an unacceptable risk under federal, state, or local law, the 

maintenance activity can be delayed until the emergency is over. 

The maintenance should be performed as soon as practicable after 

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the emergency has ended, or the unacceptable risk has 

abated.ended.

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 

on information reviewed by EPA, engine startup typically 

requires no more than 30 minutes. We received comments 

indicating that there 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, 

there are also situations where engine startup is less than 30 
minutes, for example for warm starts or if the ambient 

conditions are relatively warm. Several commenters recommended 

a minimum startup time of 30 minutes and EPA concurs that this 

amount of time would be sufficient in most cases. Sources have 

the option to petition the Administrator for a longer period of 

time to spend during engine startup. EPA believes that 

minimizing the time spent during startup and limiting the time 

spent at idle during startup are the best way to limit HAP 

emissions during startup. EPA understands that there may be 

scenarios that may require a longer startup period, e.g., for 

engines operating during cold weather conditions. However, 

commenters did not provide enough specificity in their comments, 

nor did commenters provide data, to determine whether anywhat

scenarios were appropriate to allowwould require a longer 

startup period. Owners and operators of engines at major 

sources have the option toTherefore, EPA has noted that there is 

a petition the Administrator pursuant toprocess in 40 CFR 

63.6(g) for a 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 start-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 work practice, 
based on specific factual information indicating the reason that 

a longer period is necessary for that engine. Such alternative 

work practice must be demonstrated to be no less stringent than 

EPA promulgated standards. under which these sources can be 

allowed additional startup time as appropriate.

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

setting separate standards for malfunctions in this rule. 

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 control 

equipment standard in the final rule that will 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 the crankcase emissions 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. 

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 

describedshown for stationary non-emergency CI RICE less than or 

equal to 300 HP in section III.C.Table 2 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 

500 Brake HP Located at Major Sources of Hazardous Air Pollutant 

Emissions,”Emissions” document, 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 

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 

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. 

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 

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 

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 

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 

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. WeIn light of the comments, 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 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 “Above-the-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 supported EPA’s proposed no compliance requirements 

beyond complying with the manufacturer’s instructions and no 

testing requirements for these engines. One commenter argued 

that stationary engines that are less than 100 HP should be 

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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, theThe 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 

stated that because of how EPA conducted its MACT floor 

analysis, small engines may be forced to install add-on controls 

because the MACT floor was determined by the best 12 percent of 

engines. The commenter does not believe that measurement is 

economically practicable for a small unit as the cost of 

testingmeasurement will likely exceed the value of the 

engineunit itself. The commenter urged EPA to exclude small 

sources from the category. 

 Response: EPA has reanalyzed its proposed standards based 

onagrees with the information and data presented and EPA 

concludescommenters 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 The test methods that 

sources must use to measure the emissions from these engines

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 orn

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 

could approach the cost of the engine itself. GivenGiven the 

technological requirements for properly testing the engines, 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 

““Subcategorization and MACT Floor Determination for Existing 

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

Stationary Emergency CI RICE LocatedCI Reciprocating Internal 

Combustion Engines 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, theThe 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 

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 

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reductions in HAP emitted from stationary diesel engines. The 

commenter believes that basedBased on the D.C. Court’s three 

tests, the commenter believes that 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 notes that PM is not a HAP and EPA does 

not have any data to support a relationship between PM emissions 

and HAP emissions for stationary CI engines,this source 

category, 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, itHAP; nor is notit clear that reductions in PM would 

reduce emissions of all HAP emitted from stationary engines, 

particularly emissions of formaldehyde, acetaldehyde, etc.,etc,

that represent the vast majority of the HAP emissions from this 

source category. Therefore, – therefore, at least 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.Nevertheless, EPA agrees with the commenter that there is a 

possibility that metallic HAP may not be reduced by oxidation 

catalyst control. 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)metallic HAP emissions from stationary CI engines. Most 

existing stationary CI engines have open crankcases that vent 

the crankcase emissions directly to the atmosphere. It would 

not be practicable to measure the metallic HAP emissions since 
the crankcase is open directly to the atmosphere rather than 

vented to the engine exhaust. The open crankcase is used to 

relieve pressure from the crankcase due to blow-by gases from 

the pistons. Capturing these emissions using EPA Method 29 

would be difficult due to the sporadic flowrate of the blow-by 

gases, making isokinetic sampling of the crankcase exhaust 

difficult. In addition, testing for metallic HAP is very costly 

and the emission levels from stationary CI engines are likely to 

be below method detection limits. Consequently, EPA determined 

that it would be infeasible to prescribe an emission standard 

for metallic HAP, and is promulgating as a beyond-the-floor 

requirement an equipment standard that requires stationary nonemergency diesel engines greater than 300 HP to install either 

an open or closed crankcase filtration 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. For small engines and 

emergency engines, EPA believes that meeting the work or 

management requirements specified in the final rule for changing 
the oil and filter; inspecting the air cleaner, hoses and belts; 

and operating and maintaining the engine according to the 

manufacturer’s written instructions or the maintenance plan will 

ensure that the engine is operated properly and that the engine 

wear and crankcase emissions are minimized.

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. AThe 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 

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 

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 numericalthe emission 

requirementsstandards 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, except for 

startup as discussed in section 3, 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. 

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 Emergency engines need special 

consideration, according to the commenter 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 nonemergency 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 

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 isin no controls. The 

commenter acknowledged that While 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.determinations, the 

commenter said. 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. 
 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, 
performancePerformance 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, theengines. 

The tests alone would add substantially to the fuel use of these 

engines are result in additional and unnecessary emissions and 

work. 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 
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 the 

technological and economic limitations.impracticability of 

measuring the emissions from these engines. A more detailed 

discussion of this determination can be found in the memorandum 

entitled ““Subcategorization and MACT Floor Determination for 

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

Existing Stationary Emergency CI RICE LocatedCI Reciprocating 

Internal Combustion Engines 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 proceduresit would increase the 

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required number of hours of operation of the engine beyond the 

routinely scheduled reliability testing and maintenance 

operation, thereby 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 

20025 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 procedures specified in subpart ZZZZ 

 

5

 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. 
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 impracticable 

to test the stationary engines as a result of emergency 

operation because emergencies are unplanned events and the 

owner/operator could not schedule a performance test to occur 

during an emergency. It is also 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. 

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 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 

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-floortechnology, but are 

instead based on the HAP reduction capabilities that have been 

demonstrated from certain aftertreatment devices. EPA notes 

that the rule is HAP regulation and EPA must address emissions 

of HAP, and not criteria pollutants such as PM. For the 
proposed rule, EPA’s above-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-thefloorabove-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 asconsiderably more expensive than

oxidation catalysts.6catalyst. 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. Criteria emissions from new 

 

6

 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. 
stationary diesel engines are covered under the CI NSPS in 40 

CFR part 60, subpart IIII. That subpart will in the near future 

require PM emission standards that will necessitate the use of 

CDPF on most new stationary non-emergency diesel engines.

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 

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 increasedIncreased 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 

(CT) equipped with a diesel engine used for startup of the 

turbine.CT. According to the commenter, the diesel starting 

engine, rated less than 500 HP, generally operates less than 10 

minutes per combustion turbineCT 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). 

 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 Response: EPA 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). Their short time of 

operation also makes testing of these engines using the required 

procedures impracticable. In addition, these engines operate a 

few hours per year, making further regulation of these engines 

economically impractical. In the final rule EPA has indicated 

that stationary engines used to startup combustion turbines 

should meet the same requirements as emergency engines.

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 

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. 

 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 

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.might be unwarranted. EPA indicated at 

proposal that the management practices specified in the proposal 

reflected GACT and that such practicesfor these engines 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 proposed management practices and received 

comments oninput after 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 

Formatted: Font: 10 pt, Complex Script Font:

Times New Roman, 10 pt
emission standards pursuant to section 112(d)(5)requirements for 

all engines at area sources covered bythat are not subject to 

numerical emission limits in the final rule. EPA still believes 

that a management practice approach reflects GACTis the best 

method 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 in order to 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 has included a 

provision in the final rule that allows owners/operators to work 

with state permitting authorities pursuant to 40 CFR subpart E 

(‘‘Approval of State Programs and Delegation of Federal 

Authorities’’) for 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.petition the Administrator under 40 CFR 

63.6(h) for alternative management practices for their 

engine(s).

 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 received the most information on the proposed 

frequency of changing the oil and filter. Many commenters 

indicated that the oil quality is often monitored through an oil 

testing program. Other commenters stated that several engines 

use a synthetic lubricant, which does not degrade as compared to 

other oil and can be use for extended periods of time without 

having to be replaced. Additional commenters indicating varying 

appropriate periods of oil and filter changes, including every 

250 hours to 4,000 hours. Mostly commenters indicated that 

there is not one set of maintenance procedures that can be 

applied to all engines across the board. According to the 

additional recommended maintenance procedures that EPA reviewed 
after the proposal for different engine makes and models, 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 recommended maintenance 

procedures, EPA has determined that for stationary non-emergency 

engines below 300 HP, GACT willit is appropriate to 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.first. 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 

determinedunderstands the belief of some commenters that it 

would be appropriate toshould include the option to use an oil 
analysis program in the final rule.rule; however, the commenters 

did not provide sufficient specificity regarding the parameters 

of such a program and the criteria used to determine whether oil 

change is appropriate for EPA to include such an option in the 

final rule. EPA has noted that 40 CFR 63.6(g) provides a 

mechanism for commenters to petition the Administrator to use 

such an option. 

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 

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

emissions. Therefore, EPA has required managementattempted to 

require maintenance 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 

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 

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 methods 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 

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 

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 

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 

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 

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 affecting existing stationary engines during 

periods of 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 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,continuously, where compliance is based 

on the average results of three one hour tests. EPA disagrees 

with those Regarding comments suggesting that EPA was premature 

in proposing standards during periods of startup, shutdown and 

malfunction. The malfunction, the Court of Appeals for the 

District of Columbia Circuithas 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 thatfinal decision in 

proposing requiring that EPA account for such periods, and the 

rule in March 2009.mandate regarding that decision has now been 

issued. EPA does not believe it is premature to promulgate 

final rules that are consistent with the decision of the D.C. 

Circuit.court. 

EPA proposed to apply standards during periods of startup, 

shutdown and malfunction. EPA proposed that standards for 

stationary engines during shutdown would be the same as during 

periods of normal operation. For periods of startup and 

malfunction of stationary engines located at major sources, EPA 

proposed either CO or formaldehyde emission standards, depending 

on the subcategory. For periods of startup and malfunction of 

stationary engines located at area sources, EPA proposed CO 

emission standards, formaldehyde emission standards, or 

maintenance practices, depending on the subcategory. 
As summarized in this section, numerous commenters expressed 

serious concern with regards to the proposed startup and 

malfunction requirements. Reasons commenters believed the 

startup and malfunction requirements were inappropriate include 

the lack of available emissions data during SSM periods and the 

fact that it is not possible to measure emissions during SSM 

periods. Therefore, commenters indicated that there is no 

technical basis for setting emission standards during SSM 

periods and potential emission standards would not be 

enforceable. Commenters urged EPA to adopt work practice 

standards in the final rule for periods of SSM, many of which 

were general in nature. In terms of specific work practices for 

engines during startup periods, several commenters recommended 

that EPA adopt a limit restricting the time spent during 

startup. However, EPA did not receive any specific 

recommendations for appropriate work practices to follow during 

engine shutdowns. Most commenters believe that current 

practices that are in place are sufficient to address issues 

related to shutdowns.

In a letter dated February 17, 2009 (EPA-HQ-OAR-2008-0708-

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.

EPA has determined that the emissions from stationary CI 

engines during startup are significantly different than the 

emissions during normal operation. During Emissions are higher 

during engine startup, incomplete combustion of the diesel fuel 

causes variations because the engine is not up to temperature to 

adequately reduce emissions. Aftertreatment technologies like 

oxidation catalysts and CDPFs must reach a certain temperature

in order to effectively remove emissions. In the pollutant 

concentrations and fluctuations in February 17, 2009, EMA 

letter, EMA provided various graphs illustrating sample engine 

startup and shutdown profiles and graphs demonstrating the flow 

rate of the exhaust gas. Incomplete combustion is due to cold 

areaseffect of engine exhaust temperature on catalyst 
efficiency. Figure 6 of the attachment to EMA’s letter (EPA-HQOAR-2008-0708-0019.1) shows how the CO efficiency is a function

of the cylinder walls that cause thecatalyst inlet temperature 

to be too low for efficient combustion.and reaches 70 percent 

conversion efficiency at roughly 250°C. As the engine continues 

to operate, these cold regions begin to heat up and allow for 

more complete combustioncan be seen in Figure 1 of the diesel 

fuel and stabilization of the exhaust flow rate and pollutant 

concentrations. In addition, the engine attachment to EMA’s 

letter, reaching a catalyst inlet temperature of around 250°C 

may take more than 20 minutes. The engine experiences extreme 

transient conditions during startup, including variations in 

speed and load, poor atomization of the fuel injection, which 

leadsin addition to variable engine and engine exhaust 

temperatures, variable exhaust gas flow rates, and variable 

diluent pollutant concentration.temperatures. 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),EMA’s attachment, 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 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. Therefore, EPA determined that for stationary CI 

engines, it would be appropriate to set separate requirements 

that would apply during startup. 

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 standards for stationary CI engines during 

periods of startup due because the application of measurement 

methodology to thesemeasuring emissions from stationary CI

engines during startup is not technically feasible with 

currentpracticable. 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 todetermined that 
obtaining representative results from emissions testing during 

startup operation of stationary CI engines is infeasible because 

of the relatively short term and highly variable exhaust gas 

characteristics conditions occurring during these periods. The 

innate and substantialIn particular, the unpredictable changes 

in the engine operationsair-to-fuel mixtures 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 

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 unachievabledifficult with 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. 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 that start-up 

period is longer than 30 minutes, the stack flow rate test 

period could not be short enough to represent the short term 

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

emissions calculations. These findings lead us to conclude 

thatfield testing of these engines. Further, 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. 

. EPA is therefore finalizing an operational standard in 

lieu of a numericalthe proposed emission limitstandards during 

periods of startup in accordance with section 112(h) of the CAA. 

Based on the information currently available to the 

Administrator, we believeEPA determined that this standard 

complies with limiting the startup time for the requirements of 

section 112(d), as provided for in 112(h). Theengine is the 

best way to limit HAP emissions during startup. Therefore, the
final rule requires that owners and operators of stationary 

engines limit the startup time to 30 minutes or less. Based 

on information reviewed by EPA, engine startup typically 

requires 30 minutes. 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. Several 

commenters recommended a minimum startup time of 30 minutes and 

EPA concurs that this amount of time is consistent with the 

warm-up time needed and would be sufficient in most cases.

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. EPAA 

provision is alsoincluded allowing sources to petition the 

Administrator pursuant to 40 CFR 63.6(g) for a longer period of 

time to spend during engine startup. In addition, EPA is

including a requirement in the final rule to minimize the 

engine’s time spent at idle during startup 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 

standardslimitations 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 

unnecessary 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 

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.

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 and

should not be considered a mode of operation for purposes of 

establishing standards under section 112.In establishing the 

standards in this rule, EPA has taken into account startup 

periods and has established different standards for such periods 

as appropriate. Periods of startup, normal operations, and 

shutdown are all predictable and routine aspects of a source’s 

operations. However, byBy 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, EPA has properly accounted for 

different periods of operation in establishing the standards in 

this rule. EPA does not view malfunction as a distinct 

operating mode and, therefore, 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. 

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. 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. Further, it would be difficult 

to schedule a performance test to measure emissions during 
engine malfunction due to the fact that malfunctions are 

unplanned events. 

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 expressedAs 

malfunction events will not be treated as distinct operating 

modes, they will be subject to the same performance test 

requirements, and will not be instantaneous standards. 

Therefore, if the averagemalfunction were to occur during a 

performance test, the emissions during the malfunction would be

of such a short duration as compared to the emissions averaged 

during overall testing time (three one-hour runs, or a work or 

management practice, any emissions runs) that occur prior to the 

engine shutdown should not affect a source’s abilitywould still 

be able to comply with the standard. Commenters' concerns 

regarding compliance certifications should not be a concern for 

this same reason.emission standard. This approach will also 

encourage shutdowns as soon as practicable when a malfunction 

that affects emissions occurs. As malfunction events will not 

be treated as a distinct operating mode, there is no need to 

develop a special test procedure for such events. In the highly 

unlikely event that a source fails to comply with 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 unclear 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. 

E. Emergency Engines
Comment: Several commenters (voiced concerns regarding 

potential emission limits for emergency engines and numerous 

commenters expressed particular concern with their participation 

in demand response (DR) programs. 

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 

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. 

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 
requirementsproposed revisions 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 

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. The deficiencies noted 

by various commenters are discussed further below. 

 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 

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. 

One commenter noted that the data actually shows that the 

emergency units cannot be expected to meet the CO numerical 

limit of 40 ppmvd without control devices even though the 

impacts document (a memorandum dated February 25, 2009 “Impacts 

Associated with NESHAP for Existing Stationary RICE”) states 

that it is expected that owners and operators of emergency CI 

engines will be able to meet the emissions limitation without 

any aftertreatment controls and that no control costs were 

estimated for them. The commenter cited a review of their file 

information and the EPA database as showing that there is no 
evidence that a 5-year old CI engine is likely to meet the CO 

limit without control. The commenter noted that the rigorous 

NSPS standards and the replacement of units after their 

operating lifetime is adequate for emergency units that due to 

their few operating hours emit a small fraction of HAP emitted 

from the source category.

 Response: Section 112(d)(3) of theThe 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 

developedwas developing the proposed rule. EPA acknowledges the 

commenter’s concern in regards to the use of multiple tests from 

one large engine to determine the MACT floor. However, EPA 

again 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 post-proposal period for this rulemaking. The 
additional data include tests for 1113 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 agrees with the concerns of commenters with 

regard to whetherthat the MACT floor analysis for the proposed 

rule tookdid not adequately take 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 (or lowest percent reduction if applicable) 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 in appropriate to use 

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

from the testing takes into account the variability of 

emissions. The commenters are correct that the data that was 

used to set the MACT floor was based on single runs from the 
same engine. EPA believes that it is appropriate to use this 

data. The testing was conducted at steady state conditions in a 

controlled setting and it is believed that the data is 

representative of the emissions and that the results would not 

be different if a longer sampling time was used.

Regarding the comment that emergency engines cannot meet the 

numerical limit for CO without control devices, as discussed in 

more detail in the summary of comments and responses, the final 

rule contains work or management practice requirements for 

emergency engines and does not include numeric emission 

limitations for emergency engines. 

G. Final Rule Impacts

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 

Formatted: Tab stops: Not at 0" + 0.5" + 1"

+ 1.5" + 2" + 2.5" + 3" + 3.5" + 4" + 

4.5" + 5" + 5.5" + 6"
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. 

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. 

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 

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., 

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. As 

indicated clearly in this comment summary, several members of 

industry believe that EPA has underestimated the costs 

associated with the rule and used non-representative cost 

information. Based on the significant number of comments 

received on the proposed rule costs, EPA revisited itsthe cost 

analysis and assumptions underlying the proposed rule and 

revised that analysis and assumptions in for the final rule. 

 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.proposed, which addresses the comment that 90 

percent reduction is not achievable. 

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 

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. 

 Regarding the concerns expressed by the commenters about 

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

requires does not require 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 therefore, EPA does not 

believe that any of these engines will be retrofit with 

aftertreatment controls or be. The final rule also does not 

contain any performance tested to determine compliance.testing 

requirements for existing stationary emergency engines. 
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 

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, and SOx

reductions are expected to be more than 5,000 tpy in the year 

2013. Emissions of VOC are estimated to be reduced by 27,000 

tpy in the year 2013. 

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$380 million in year 2013 (the 

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? estimates?

 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 We 

estimate the monetized co-benefits of this final regulatory 

action to be $1.1 billion to $2.6 billion (2008$, 3 percent 

discount rate) in the fifth year (2013). The PM2.5 co-benefits at 

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a 7 percent discount rate are $960 million to $2.3 billion 

(2008$). Because the magnitude of the PM2.5 co-benefits is 

largely driven by the concentration-response function for 

premature mortality, we examined Using alternate relationships 

between PM2.5 and premature mortality supplied by experts. 

Higherexperts, higher and lower co-benefits estimates are 

plausible, but most of the expert-based estimates fall between 

these two estimates above.7

 

7

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

Impact of Changes in Ambient Fine Particulate Matter in the U.S. 

Environ. Sci. Technol., 42, 7, 2268 – 2274.
Draft RICE NESHAP FRM 1-11-10

.5 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 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 

SO2 5,100 $120 to $290 $110 to $260 

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

 Total: $1,100 to $2,600 $960 to $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 These benefits estimates of population-level 

improvements to are the human health co-benefits for populations 

exposed to PM2.5 from reductions in PM2.5 air pollution.pollutants. 

We generated estimates that represent the total monetized human 

health co-benefits (the sum of premature mortality and 

morbidity) of reducing a ton of PM2.5 and PM2.5 precursor 

emissions. We base the estimate of human health co-benefits 

 

5 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.

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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 RIARegulatory Impact 

Analysis (RIA) for the 2008 National Ambient Air Quality 

Standard for Ground-level Ozone (NAAQS) and Fann et al. (2009)6. 

 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 

consider a variety of assumptions, including estimates based 

 

6

 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. 

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128 

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 study7 and the extended Six Cities cohort study.8

study9. 

 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 

 

7

 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

8

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

Pollution and Mortality.” American Journal of Respiratory and 

Critical Care Medicine. 173: 667-672 9 Laden et al, 2006. “Reduction in Fine Particulate Air Pollution and 

Mortality.” American Journal of Respiratory and Critical Care Medicine. 

173: 667-672

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Particulate Matter10, 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 

 

10 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.

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130 

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 HAPshazardous air pollutants 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. 

 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$380

million (2008$) in the fifth year, and the co-benefits are 

estimated at $1.1 billion to $2.6 billion (2008$, 3 percent 

discount rate) for that same year. The co-benefits at a 7 

percent discount rate are $960 million to $2.3 billion (2008$). 

Thus, net benefits of this rulemaking are estimated at $680 

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131 

million to $2.2 billion (2008$, 3 percent discount rate)and 

$590$580 million to $2.0 billion (2008$, 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 

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)(“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. 

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132 

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 $380 million 

(2008 dollars), which is the same as the estimated compliance 

costs. 

 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 
133 

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 

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 
134 

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. 

 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 
135 

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 

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 
136 

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. 

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. 
137 

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 

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 
138 

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 

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. 
139 

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 

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. The 

regulatory alternative upon which the rule is based is the least 

costly, most cost-effective alternative to achieve the statutory 

requirements of Clean Air Act section 112. 

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 
140 

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 $380 million (2008 dollars). It is estimated that by 2013, 

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, 

and SOx reductions are expected to be more than 5,100 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 

$1.1 to $2.6 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 
141 

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 

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
142 

 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 

governments. Thus, Executive Order 13132 does not apply to the 

final rule. 

In the spirit of Executive Order 13132, and consistent with 

EPA policy to promote communications between EPA and State and 

local governments, EPA specifically solicited comment on the 

proposed rule from State and local officials. 

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments

 This action does not have tribal implications, as specified 

in Executive Order 13175 (65 FR 67249, November 9, 2000). It 

will not have substantial direct effects on tribal governments, 

on the relationship between the Federal government and Indian 

tribes, or on the distribution of power and responsibilities 

between the Federal government and Indian tribes, as specified 

in Executive Order 13175. Thus, Executive Order 13175 does not 

apply to the final rule. 

G. Executive Order 13045: Protection of Children from 
143 

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

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 
144 

data describing energy consumption for the electric power 

sector. The electric power sector is expected to incur about 80 

percent of the $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 

section, the electric power sector accounts for less 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. 
145 

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 

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146 

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 didis not considering 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 
147 

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 148 of 208 

Draft RICE NESHAP FRM 1-11-10

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. 

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Draft RICE NESHAP FRM 1-11-10

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 
150 

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 
151 

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. 

* * * * * 
152 

(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? 
153 

* * * 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 
154 

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 Tables 1b and 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 CO emission standards 

specified in Table 2d to this subpart. Existing stationary nonemergency CI RICE greater than 300 HP located at area sources in 

areas of Alaska not accessible by the FAHS must meet the 

maintenance practices that are shown for stationary nonemergency 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 
155 

requirements in 40 CFR 80.510(b) for nonroad diesel fuel. 

Existing non-emergency CI stationary RICE located in Guam, 

American Samoa, the Commonwealth of the Northern Mariana 

Islands, or at area sources in areas of Alaska 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 timesIf you must comply with emission 

limitations and operating limitations, you must operate and 

maintain any affected source,your stationary RICE, 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 
156 

operation and maintenance procedures, review of operation and 

maintenance records, and inspection of the source. at all times. 

* * * * * 

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 
157 

conditions described in paragraphs (b)(1) through (4) of this 

section. 

(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 in §63.7(e)(1) and under the specific conditions 

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 
158 

a non-operational engine can conduct the performance test when 

the engine is started up again. 

 (c) [Reserved] 

* * * * * 

12. Section 63.6625 is amended: by adding paragraphs (e), 

(f), (g), (h), (i), and (j) to read as follows:

(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);

(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 
159 

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. 

(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 

equippedlocated at an area source or major source of HAP 

emissions with a closed crankcase ventilation system,that is 

open to the atmosphere, 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 
160 

the crankcase filters, or can request the Administrator to 

approve different maintenance requirements that are as 

protective as manufacturer requirements. Existing CI engines 

located in areas of Alaska not accessible by the FAHS do not 

have to meet the requirements of paragraph (g) in this section. 

(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 limitations 

apply. Sources have the option pursuant to 40 CFR 63.6(g) to 

petition the Administrator for a longer period of time for

engine startup. Any petition must be based on specific factual 

information indicating the reason that a longer period is 

necessary for that engine.

(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 toof this subpart, you have the option of 

utilizingpetitioning the Administrator pursuant to 40 CFR 

63.6(g) to utilize an oil analysis program in order to extend 

the specified oil change requirement in Tables 2c and 2d to this 

subpart. The analysis program must at a minimum analyze the 

following three parameters: Total Base Number, viscosity, and 

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161 

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 may [insert 

discussion of what engine o/o should do]. If any of the limits 

are exceeded, the engine owner or operator must change the 

oil.of this subpart. The program must at a minimum include 

analysis of the total base number, viscosity, and percent water 

content by volume of the oil. 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 operateoperator a stationary engine that 

is subject to the work, operation or management practices in 

Table 2c or 2d to this subpart or paragraph (h) of this 

section,subpart, you have the option to petition the 

Administrator pursuant to §40 CFR 63.6(g)for approval of 

alternative work, operation or management practices. Any 

alternative work, operation or management practices must be at 

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162 

least as stringent as those specified in Tables 2c and 2d toof

this subpart, as appropriate. 

13. Section 63.6640 is amended by:

revising paragraphs (a) Revising paragraph (a);

, (b) Revising paragraph (b); 

(c) Revising paragraph, (d); 

(d) Revising paragraph(d), and (e); and

(e) Adding 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 

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163 

operating parameters, you must also conduct a performance test 

to demonstrate that you are meeting the required emission 

limitation applicable to your stationary RICE. 

* * * * * 

(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 emergency stationary RICE, or an existing stationary RICE 
164 

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 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. 
165 

(2) There is no time limit on the use of emergency 

stationary RICE in emergency situations. 

(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 
166 

regional transmission organization or equivalent balancing 

authority and transmission operator has determined there are 

emergency conditions that could lead to a potential electrical 

blackout, such as unusually low frequency, equipment overload, 

capacity or energy deficiency, or unacceptable voltage level. 

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

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

the engine operation must be terminated immediately after the 

facility is notified that the emergency condition is no longer 

imminent. The 15 hours per year of demand response operation 

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

provided for non-emergency situations. 

 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. 

 (2) An existing stationary CI RICE located at an area 

source of HAP emissions. 
167 

 (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 63.6655 is amended by adding paragraphs (e) 

and (f) to read as follows: 

§63.6655 What records must I keep?

* * * * * 

 (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. 
168 

 (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 

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. 

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?
169 

* * * * * 

 (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). 

 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 

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: 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 
170 

HP located at a major source of HAP emissions, you do not need 

to comply with the requirements in the General Provisions 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. 

 18. Section 63.6675 is amended:Section 63.6675 is revised 

to modify the definitions of Diesel fuel and Emergency 

stationary RICE, and to add the definitions of Black start 

engine, Engine startup, and Residential/commercial/institutional 

emergency stationary RICE, in alphabetical order, to read to 

read as follows:

 (a) By revising the definition of Diesel fuel;

 (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?

* * * * * 
171 

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 

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 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 

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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 nonemergency situations. All other emergency stationary RICE must 

comply with the requirements specified in §63.6640(f). 

 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 
173 

establishments such as office buildings, hotels, or stores, or 

institutional establishments such as medical centers, research 

centers, and institutions of higher education. 

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 

stationary 

RICE 

a. Reduce 

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 

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 nonstartup emission 

limitations apply.1
174 

O2. 

1 Sources have the option to petition the Administrator 

pursuant to 40 CFR 63.6(g) for alternative work practices.

longer period of time for engine startup. Any petition must 

be based on specific factual information indicating the reason 

that an alternative work practice longer period is at least as 

stringent as those specified in Table 1a of this 

subpart.necessary for that engine.

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 

startup. . . 

During periods of 

startup you must... 

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 

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
175 

limit concentration 

of formaldehyde to 

17 ppmvd or less at 

15 percent O2 until 

June 15, 2007. 

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 have the option to petition the Administrator 

pursuant to 40 CFR 63.6(g) for alternative work practices.

longer period of time for engine startup. Any petition must 

be based on specific factual information indicating the reason 

that an alternative work practice longer period is at least as 

stringent as those specified in Table 2a of this 

subpart.necessary for that engine.

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 
176 

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

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 may petition for a different temperature 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 the rule. 

22. Subpart ZZZZ of Part 63 is amended by adding Tables 2c 

and 2d to Subpart ZZZZ of Part 63 to read as follows: 

Formatted Table
177 

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: within 10 percent of 100 percent peak load (or 

the highest achievable):

For each... You must meet the 

following requirement, 

except during periods of 

startup... 

During periods of 

startup you must... 

1. Emergency CI 

<100 HP and 

black start CI.1

<100 HP.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.4

 

2. NonEmergency, nonblack start CI 

<100 HP. 

 

a. Change oil and filter 

every 1,000 hours of 

operation or annually, 

whichever comes 

first2

;first1;

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

necessary.2

3. NonEmergency, nonblack start CI 

RICE 100<HP<300 

HP. 

Limit concentration of CO 

in the stationary RICE 

exhaust to 230157 ppmvd 

or less at 15 percent O2. 
178 

4. NonEmergency, nonCI 100<HP<500

and black 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

a. Change oil and filter 

every 500 hours of 

operation or annually, 

whichever comes first2; 

b. Inspect air cleaner 

every 1000 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 

necessary3.b. Reduce CO 

emissions by 70 percent 

or more. 

5. NonEmergency, nonblack start 

CI>500 HP.

300<HP<500.

a. Limit concentration of 

CO in the stationary RICE 

exhaust to 2346 ppmvd or 

less at 15 percent O2; or

b. Reduce CO emissions by 

70 percent or more.

6. 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 

managementwork practice requirements on the schedule required 

inschedule, the final rule, or if shutting the engine down would 

otherwise pose an unacceptable risk under federal, state, or 

local law, the managementwork practice can be delayed until the 

emergency is over. The managementwork practice should be 

performed as soon as practicable after the emergency has ended, 

or the unacceptable risk has abated.ended. 

2

Sources have the option to petition the Administrator pursuant 

to 40 CFR 63.6(g) 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. rule. 3 Sources have the option to petition the Administrator pursuant 

to 40 CFR 63.6(g) for approval of alternative maintenance 
179 

practices. The alternative maintenance practices must be at 

least as stringent as those specified in Table 2c of this 

subpart.rule. 4 Sources have the option to petition the Administrator pursuant 

to 40 CFR 63.6(g) for alternative work practices. longer period 

of time for engine startup. Any petition must be based on 

specific factual information indicating the reason that an 

alternative work practice longer period is at least as stringent 

as those specified in Table 2c of this subpart.necessary for 

that engine.

Table 2d to Subpart ZZZZ of Part 63. Requirements Emission 

Limitations 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: within 10 percent of 100 

percent peak load (or the highest achievable):

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; 

c. Inspect all 

hoses and belts 

every 500 hours of 

operation or 

annually, whichever 

comes first, and 

replace as 

necessary.2

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

Formatted: Font color: Auto, Complex Script

Font: Times New Roman
180 

2. Non-Emergency, 

non-black start CI 

300<HP<500. 

a. Limit 

concentration of CO 

in the stationary 

RICE exhaust to 

4946 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. 

4. Emergency CI 

and black start 

CI.4

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 2

Sources have the option the petition the Administrator 

pursuant to 40 CFR 63.6(g) 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 rule. 

2 Sources have the option to work with state permitting

authoritiespetition the Administrator pursuant to 40 CFR subpart 

E63.6(g) for approval of alternative maintenance practices. The 

Formatted: Font color: Black, Complex Script

Font: Times New Roman
181 

alternative maintenance practices must be at least as stringent 

as those specified in Table 2d of this subpart.rule. 3 Sources have the option to work with state permitting

authoritiespetition the Administrator pursuant to 40 CFR subpart 

E63.6(g) for approval longer period of a alternative work 

practicetime for engine startup. The alternative work 

practice(s)Any petition must be demonstrated to be no less 

stringent than those specified in Table 2(d) of this 

subpart.based on specific factual information indicating the 

reason that a longer period is necessary for that engine. 4 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 the 

final rule, or if shutting the engine down would otherwise pose 

an unacceptable risk under federal, state, or local law, the 

management practice can be delayed until the emergency is over. 

The management practice should be performed as soon as 

practicable after the emergency has ended, or the unacceptable 

risk has abated.ended.

 23. Table 3 to Subpart ZZZZ of Part 63 is amended to read 

be revised as follows: 

Table 3 to Subpart ZZZZ of Part 63. Subsequent Performance Tests 

As stated in §§63.6615 and 63.6620, you must comply with the 

following subsequent performance test requirements: 

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 

Reduce 

formaldehyde 

emissions 

Conduct subsequent 

performance tests 

semiannually1

. 
182 

sources. 

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. 

25. Table 4 to Subpart ZZZZ of Part 63 is amended to 

readbe revised 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 

(1) 

portable 

CO and 

O2 

analyzer 

(a) using 

ASTM D6522-

00 (2005)a

(incorporated by 

reference, 

see §63.14). 

Measurements 
183 

device; 

and 

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 

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. 
184 

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. 
185 

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 
186 

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. 
187 

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, 
188 

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 

readbe revised 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 . . . 

Formatted: Line spacing: Double

Formatted: Font: Bold, Font color: Auto,

Complex Script Font: Times New Roman, 10 pt
189 

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 
190 

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 
191 

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 
192 

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 
193 

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. 
194 

26. Table 6 to Subpart ZZZZ of Part 63 is amended to 

readbe revised 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 
195 

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), 
196 

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 
197 

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 
198 

>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 
199 

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 
200 

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 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 
201 

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)

(1)

Operation and 

maintenance 

NoYes Additional 

requirements are 

specified in 

§63.6625 and in 

Tables 2d and 6 

to this subpart.
202 

§63.6(f)(1)§63.

6(e)(2)

[Reserved]Applicabi

lity of standards 

No

§63.6(e)(3) Startup, shutdown, 

and malfunction 

plan

Yes

§63.6(f)(1) Applicability of 

standards 

No

§63.6(f)(2) Methods for 

determining 

compliance 

Yes 

§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 
203 

§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 

performance tests 

No. 

Yes

Subpart ZZZZ 

specifies 

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 
204 

§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 

maintenance 

requirements 

Yes 

§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. 
205 

§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. 

§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. 
206 

§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 

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 

Yes 

§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) Records of Yes 
207 

(xiv) supporting 

documentation 

§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 

Requirements 

Yes 

§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 

Yes 

§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 
208