`[Federal Register Volume 89, Number 15 (Tuesday, January 23, 2024)]
[Proposed Rules]
[Pages 4243-4268]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-00747]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2017-0183; FRL 5120-02-OAR]
RIN 2060-AO18


Standards of Performance for New Stationary Sources and Emission 
Guidelines for Existing Sources: Large Municipal Waste Combustors 
Voluntary Remand Response and 5-Year Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing amendments to the new source

[[Page 4244]]

performance standards (NSPS) and emission guidelines (EG) for large 
municipal waste combustion (MWC) units. These proposed amendments 
reflect the results from a reevaluation of the maximum achievable 
control technology (MACT) floor levels, a 5-year review, and the 
removal of startup, shutdown and malfunction exclusions and exceptions. 
These proposed amendments also streamline regulatory language, revise 
recordkeeping and electronic notification and reporting requirements, 
re-establish new and existing source applicability dates, clarify 
requirements for certain air curtain incinerators, close a 2007 
proposed reconsideration action, correct certain typographical errors, 
make certain technical corrections, and clarify certain provisions in 
the NSPS and EG. These proposed amendments would revise all emission 
limits in the EG, except for carbon monoxide (CO) limits for two 
subcategories of combustors, and all nine emission limits in the NSPS. 
The EPA is reevaluating the MACT floors in response to the EPA's 
voluntary remand of the large MWC rules following a petitioner's 
request that the EPA review the MACT floors for large MWC units in 
consideration of a D.C. Circuit Court decision on MACT floor issues. 
The 5-year review is required by the Clean Air Act (CAA). The proposed 
amendments would result in an estimated 14,000 tons per year reduction 
in regulated pollutants.

DATES: Comments must be received on or before March 25, 2024. Under the 
Paperwork Reduction Act (PRA), comments on the information collection 
provisions are best assured of consideration if the Office of 
Management and Budget (OMB) receives a copy of your comments on or 
before February 22, 2024.
    Public hearing: If anyone contacts us requesting a public hearing 
on or before January 29, 2024, we will hold a virtual public hearing. 
See SUPPLEMENTARY INFORMATION for information on requesting and 
registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2017-0183, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2017-0183 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2017-0183.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2017-0183, Mail Code 28221T, 1200 
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Charlene E. Spells, Sector Policies and Programs 
Division (E143-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, P.O. Box 
12055, North Carolina 27711; telephone number: (919) 541-5255; email 
address: [email protected].

SUPPLEMENTARY INFORMATION: 
    Participation in virtual public hearing. To request a virtual 
public hearing, contact the public hearing team at (888) 372-8699 or by 
email at [email protected]. If requested, the hearing will be 
held via virtual platform on February 7, 2024. The hearing will convene 
at 11:00 a.m. Eastern Time (ET) and will conclude at 7:00 p.m. ET. The 
EPA may close a session 15 minutes after the last pre-registered 
speaker has testified if there are no additional speakers. The EPA will 
announce further details at https://www.epa.gov/stationary-sources-air-pollution/large-municipal-waste-combustors-lmwc-new-source-performance.
    If a public hearing is requested, the EPA will begin pre-
registering speakers for the hearing no later than 1 business day after 
a request has been received. To register to speak at the virtual 
hearing, please use the online registration form available at https://www.epa.gov/https://www.epa.gov/stationary-sources-air-pollution/large-municipal-waste-combustors-lmwc-new-source-performance or contact the 
public hearing team at (888) 372-8699 or by email at 
[email protected]. The last day to pre-register to speak at the 
hearing will be February 5, 2024. Prior to the hearing, the EPA will 
post a general agenda that will list pre-registered speakers in 
approximate order at: https://www.epa.gov/stationary-sources-air-pollution/large-municipal-waste-combustors-lmwc-new-source-performance.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 4 minutes to provide oral testimony. The 
EPA encourages commenters to provide the EPA with a copy of their oral 
testimony electronically (via email) by emailing it to 
[email protected]. The EPA also recommends submitting the text of 
your oral testimony as written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will 
be posted online at https://www.epa.gov/stationary-sources-air-pollution/large-municipal-waste-combustors-lmwc-new-source-performance. 
While the EPA expects the hearing to go forward as set forth above, 
please monitor our website or contact the public hearing team at (888) 
372-8699 or by email at [email protected] to determine if there 
are any updates. The EPA does not intend to publish a document in the 
Federal Register announcing updates.
    If you require the services of a translator or special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team and describe your needs by January 
30, 2024. The EPA may not be able to arrange accommodations without 
advanced notice.
    Docket: The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2017-0183. All documents in the docket are 
listed in https://www.regulations.gov/. Although listed, 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. With the

[[Page 4245]]

exception of such material, publicly available docket materials are 
available electronically in Regulations.gov.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2017-0183. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov/, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit electronically to https://www.regulations.gov/ 
any information that you consider to be CBI or other information whose 
disclosure is restricted by statute. This type of information should be 
submitted as discussed below.
    The EPA may publish any comment received to its public docket. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the Web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov/, your email address will be automatically 
captured and included as part of the comment that is placed in the 
public docket and made available on the internet. If you submit an 
electronic comment, the EPA recommends that you include your name and 
other contact information in the body of your comment and with any 
digital storage media you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI: Do not submit information containing CBI to the EPA 
through https://www.regulations.gov/. Clearly mark the part or all of 
the information that you claim to be CBI. For CBI information on any 
digital storage media that you mail to the EPA, note the docket ID, 
mark the outside of the digital storage media as CBI, and identify 
electronically within the digital storage media the specific 
information that is claimed as CBI. In addition to one complete version 
of the comments that includes information claimed as CBI, you must 
submit a copy of the comments that does not contain the information 
claimed as CBI directly to the public docket through the procedures 
outlined in Instructions above. If you submit any digital storage media 
that does not contain CBI, mark the outside of the digital storage 
media clearly that it does not contain CBI and note the docket ID. 
Information not marked as CBI will be included in the public docket and 
the EPA's electronic public docket without prior notice. Information 
marked as CBI will not be disclosed except in accordance with 
procedures set forth in 40 Code of Federal Regulations (CFR) part 2.
    Our preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol (FTP), 
or other online file sharing services (e.g., Dropbox, OneDrive, Google 
Drive). Electronic submissions must be transmitted directly to the 
Office of Air Quality Planning and Standards (OAQPS) CBI Office at the 
email address [email protected], and should include clear CBI markings 
and note the docket ID. If you need assistance with submitting large 
electronic files that exceed the file size limit for email attachments, 
and if you do not have your own file sharing service, please email 
[email protected] to request a file transfer link. If sending CBI 
information through the postal service, please send it to the following 
address: OAQPS Document Control Officer (C404-02), OAQPS, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711, Attention Docket ID No. EPA-HQ-OAR-2017-0183. The mailed CBI 
material should be double wrapped and clearly marked. Any CBI markings 
should not show through the outer envelope.
    Preamble acronyms and abbreviations. Throughout this preamble the 
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. We 
use multiple acronyms and terms in this preamble. While this list may 
not be exhaustive, to ease the reading of this preamble and for 
reference purposes, the EPA defines the following terms and acronyms 
here:

ACI activated carbon injection
ANSI American National Standards Institute
APCD air pollution control device
ASME American Society of Mechanical Engineers
ASNCR advanced selective noncatalytic reduction
CAA Clean Air Act
CBI Confidential Business Information
Cd cadmium
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emissions monitoring system
CFR Code of Federal Regulations
CISWI Commercial and Industrial Solid Waste Units
CO carbon monoxide
EAV equivalent annualized value
EG emission guidelines
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
HAP hazardous air pollutant(s)
HCl hydrogen chloride
Hg mercury
ICR Information Collection Request
LNTM Low NOX
MACT maximum achievable control technology
MSW municipal solid waste
MWC municipal waste combustor
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NOX oxides of nitrogen (nitrogen oxides)
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OTR Ozone Transport Region
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
Pb lead
PCDD/PCDF polychlorinated dibenzodioxins and dibenzofurans (dioxins/
furans)
PDF portable document format
PM particulate matter
ppm parts per million
PRA Paperwork Reduction Act
PV present value
QRO Certification for Municipal Solid Waste Combustion Facilities 
Operator
RFA Regulatory Flexibility Act
RDL representative detection level
RDF/FBC refuse derived fuel fluidized bed combustor
RDF/S refuse-derived fuel stoker combustor
RDF/SS refuse derived fuel semi-suspension or spreader stoker wet 
process conversion combustor
RIA Regulatory Impact Analysis
SCR selective catalytic reduction
SNCR selective noncatalytic reduction
SO2 sulfur dioxide
SSM startup, shutdown, and malfunction
tpd tons per day
tpy tons per year
UMRA Unfunded Mandates Reform Act of 1995
UPL upper prediction limit

[[Page 4246]]

VCS voluntary consensus standards

    Organization of this document. The information in this preamble is 
organized as follows:

I. General Information
    A. Executive Summary
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related 
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is the regulatory background for this source category?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
    E. How does the EPA perform the 5-year review?
    F. What outreach and engagement did the EPA conduct?
III. Analytical Results and Proposed Decisions
    A. What are the results and proposed decisions based on our 5-
year review and response to the voluntary MACT floor remand, and 
what is the rationale for those decisions?
    B. What other actions are we proposing, and what is the 
rationale for those actions?
    C. What compliance dates are we proposing, and what is the 
rationale for the proposed compliance dates?
IV. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the water, solid waste, and energy impacts?
    D. What are the cost impacts?
    E. What are the economic impacts?
    F. What are the benefits?
    G. What environmental justice analysis did we conduct?
V. Request for Comments
VI. Statutory and Executive Order Reviews and 1 CFR Part 51
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act of 1995 (UMRA)
    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 Risks 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 (NTTAA) and 
1 CFR Part 51
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority and Executive Order 14096: 
Revitalizing Our Nation's Commitment to Environmental Justice for 
All Populations and Low-Income Populations

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    The EPA is proposing to revise the standards of performance for new 
stationary sources (new source performance standards, or NSPS) and 
emission guidelines (EG) for existing sources for large municipal waste 
combustors (MWCs) by amending existing standards for the large MWC 
source category, which comprises incinerators that combust greater than 
250 tons per day (tpd) of municipal solid waste (MSW). The EPA is 
exercising its authority under section 129 of the Clean Air Act (CAA). 
The proposed standards would increase stringency of existing regulation 
of emissions of the nine pollutants listed in CAA section 129: cadmium 
(Cd), mercury (Hg), lead (Pb), particulate matter (PM), hydrogen 
chloride (HCl), sulfur dioxide (SO2), polychlorinated 
dibenzodioxins and dibenzofurans (dioxins/furans or PCDD/PCDF), carbon 
monoxide (CO), and oxides of nitrogen (NOX).
2. Summary of the Major Provisions of the Regulatory Action in Question
    These proposed amendments reflect the results from a reevaluation 
of the maximum achievable control technology (MACT) floor, a 5-year 
review, and the removal of startup, shutdown and malfunction (SSM) 
exclusions and exceptions. These proposed amendments also streamline 
regulatory language, revise recordkeeping and electronic reporting 
requirements, re-establish new and existing source applicability dates, 
clarify requirements for air curtain incinerators, close a 2007 
proposed reconsideration action, correct certain typographical errors, 
make certain technical corrections, and clarify certain provisions in 
the NSPS and EG. Specifically, the major proposed amendments would do 
the following:
     Revise all emission limits in the EG, except for CO limits 
for two combustor subcategories, and all nine emission limits in the 
NSPS. With the exception of NOX, the proposed standards are 
the result of a reevaluation of the MACT floors in response to the D.C. 
Circuit's 2008 remand of the large MWC rules.\1\ At the same time this 
reevaluation took place, the EPA conducted a 5-year review as required 
by CAA section 129(a)(5). As a result of this review, the EPA is 
proposing NOX standards that are more stringent than the 
reevaluated MACT floor emissions limits for NOX and are 
consistent with the recently promulgated Good Neighbor Plan \2\ which 
set ozone season standards for a significant portion of the large MWC 
source category.
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    \1\ Order, Sierra Club v. EPA, No. 06-1250 (D.C. Cir. filed Feb. 
15, 2008).
    \2\ https://www.epa.gov/csapr/good-neighbor-plan-2015-ozone-naaqs.
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     Remove the alternative percent reduction standards and 
NOX emissions averaging allowance for existing sources and 
replace them with a numeric concentration-based emission limits only. 
This would establish a consistent approach to compliance for all 
facilities.
     Remove SSM exclusions and exceptions and significantly 
revise monitoring provisions during these periods. For NOX, 
SO2, and CO, where a continuous emissions monitoring system 
(CEMS) continuously measures the pollutant concentration, we propose 
eliminating the exclusions of periods of SSM from CEMS data averaging 
calculations present in the 1995 large MWC rules and replacing them 
with a monitoring and compliance demonstration approach used in the 
more recent CAA section 129 rulemaking for Commercial and Industrial 
Solid Waste Units (CISWI) NSPS and EG.
     Streamline regulatory language to be more accessible than 
the 1995 large MWC rule. Primarily, convert text describing emission 
standards and performance testing requirements from paragraphs into 
tables to facilitate easier implementation and understanding of the 
requirements.
     Revise recordkeeping and electronic reporting requirements 
for source owners and operators to submit electronic copies of required 
performance test reports, performance evaluation reports, semiannual 
compliance reports, and annual reports through the EPA's Central Data 
Exchange (CDX) using the Compliance and Emissions Data Reporting 
Interface (CEDRI). The electronic submittal of the reports addressed in 
this proposed rulemaking will increase the usefulness of the data 
contained in those reports and will improve availability and 
transparency.
     Re-establish new and existing source applicability so that 
large MWC units currently subject to the NSPS would become ``existing'' 
sources under the proposed amended standards and would be required to 
meet the revised EG by the applicable compliance date for the revised 
guidelines. Large MWC

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units that commence construction after the date of this proposal or 
commence a modification on or after the date 6 months after 
promulgation of the amended standards, would be ``new'' units subject 
to the more stringent NSPS emission limits.
     Clarify requirements for air curtain incinerators that 
burn only wood waste, clean lumber, and yard waste or a mixture of 
these materials. The EPA is proposing to eliminate the regulatory title 
V permitting requirement for air curtain incinerators that are not 
located at a major source or subject to title V for other reasons.
3. Costs and Benefits
    Table 1 of this preamble summarizes the monetized benefits, costs, 
and emissions reductions of this proposed action for new and existing 
large MWCs from 2025 through 2044. As indicated in Table 1, the EPA 
projects that the proposed amendments would result in an estimated 
14,000 tons per year reduction in regulated pollutants. The EPA 
conducted an economic analysis for this proposal, as detailed in the 
document Regulatory Impact Analysis for the Proposed Standards of 
Performance for New Stationary Sources and Emission Guidelines for 
Existing Sources: Large Municipal Waste Combustors (referred to as the 
RIA in this document). The RIA is available in the docket and is also 
briefly summarized in section IV of this preamble.

             Table 1--Monetized Benefits, Costs, Net Benefits, and Emissions Reductions of the Proposed NSPS and EG Amendments, 2025-2044 a
                                           [Dollar estimates in millions of 2022 dollars, discounted to 2023]
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                                                  3 Percent discount rate                                      7 Percent discount rate
                              --------------------------------------------------------------------------------------------------------------------------
                                       Present value           Equivalent annualized value           Present value           Equivalent annualized value
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Benefits \b\.................  $5,100 and $16,000...........  $340 and $1,100..............  $3,100 and $9,800............  $290 and $920.
Compliance costs.............  $1,700.......................  $110.........................  $1,200.......................  $120.
Net benefits.................  $3,400 and $14,000...........  $230 and $970................  $1,800 and $8,500............  $170 and $800.
                              --------------------------------------------------------------------------------------------------------------------------
Emissions reductions (short    Total for period of analysis (years 2025-2044):
 tons).
Mercury......................   1,100 pounds.
Dioxins/Furans...............   1000 grams.
Hydrogen Chloride............   6,900 short tons.
Sulfur Dioxide...............   48,000 short tons.
Nitrogen Oxides..............   230,000 short tons.
Cadmium......................   0.89 short tons.
Lead.........................   3.6 short tons.
PM...........................   490 short tons.
PM <2.5 microns (PM2.5)......   280 short tons.
Non-monetized benefits in      Health and environmental benefits from reducing 6,900 short tons of HAP from 2025 to 2044.
 this table.
                               Non-health benefits from reducing 490 short tons of PM, of which 280 short tons are PM2.5, from 2025 to 2044.
                               Visibility benefits.
                               Reduced ecosystem/vegetation effects.
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\a\ Totals may not sum due to independent rounding. Numbers rounded to two significant digits unless otherwise noted.
\b\ Monetized benefits include health benefits associated with reductions in PM2.5 concentrations from reductions in directly emitted PM2.5 and
  precursors such as SO2 and NOX. The monetized health benefits are quantified using two alternative concentration-response relationships from Di et al.
  (2016) and Turner et al. (2017).

B. Does this action apply to me?

    This proposal applies to large MWCs that combust more than 250 tpd 
of MSW as defined under section129(a)(1)(B) of the 1990 CAA Amendments 
(See Pub. L 101-549, title III, section 305(a), November 15, 1990, 104 
Stat. 2577) and regulated under 40 CFR part 60, subparts Cb and Eb. The 
North American Industry Classification System (NAICS) codes for the 
large municipal waste industry are 562213 and 924110. This list of 
categories and NAICS codes is not intended to be exhaustive, but rather 
provides a guide for readers regarding the entities that this proposed 
action is likely to affect. The proposed standards, once promulgated, 
will be directly applicable to the affected sources. Some large MWCs 
are owned and operated by local or municipal governments, and thus 
would be affected by this proposed action.

C. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this action is available on the internet. Following signature by the 
EPA Administrator, the EPA will post a copy of this proposed action at 
https://www.epa.gov/stationary-sources-air-pollution/large-municipal-waste-combustors-lmwc-new-source-performance. Following publication in 
the Federal Register, the EPA will post the Federal Register version of 
the proposal and key technical documents at this same website.
    A memorandum showing the rule edits that would be necessary to 
incorporate the changes to 40 CFR part 60, subparts Cb and Eb \3\ 
proposed in this action is available in the docket (Docket ID No. EPA-
HQ-OAR-2017-0183). Following signature by the EPA Administrator, the 
EPA also will post a copy of this document to https://www.epa.gov/stationary-sources-air-pollution/large-municipal-waste-combustors-lmwc-new-source-performance.
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    \3\ Note that the EPA is not proposing any amendments to 40 CFR 
part 60 subpart Ea at this time, but may reserve this subpart in a 
future action, as discussed later in this preamble.
---------------------------------------------------------------------------

II. Background

A. What is the statutory authority for this action?

    The statutory authority for this action is provided by section 129 
of the CAA. CAA section 129 requires the EPA to establish NSPS and EG 
pursuant to CAA

[[Page 4248]]

sections 111 and 129 for new and existing solid waste incineration 
units, including ``incineration units with capacity greater than 250 
tpd combusting municipal waste.'' This action amends the large MWC 
standards under such authority. In addition, CAA section 129(a)(5) 
specifically requires the EPA to review the standards at 5-year 
intervals and, if appropriate, revise the standards and the 
requirements for solid waste incineration units, including large MWC 
units.
    In setting forth the methodology that the EPA must use to establish 
the first-stage technology-based standards, CAA section 129(a)(2) 
provides that standards ``applicable to solid waste incineration units 
promulgated under . . . [section 111] and this section shall reflect 
the maximum degree of reduction in emissions of . . . [certain listed 
air pollutants] that the Administrator, taking into consideration the 
cost of achieving such emission reduction and any non-air quality 
health and environmental impacts and energy requirements, determines is 
achievable for new and existing units in each category.'' This level of 
control is referred to as a maximum achievable control technology, or 
MACT standard. CAA section 129(a)(4) further directs the EPA to set 
numeric emission limits for certain enumerated pollutants (Cd, CO, 
PCDD/PCDF, HCl, Pb, Hg, NOX, PM, and SO2). In 
addition, the standards ``shall be based on methods and technologies 
for removal or destruction of pollutants'' according to CAA section 
129(a)(3). The EPA has substantial discretion to distinguish among 
classes, types, and sizes of incinerator units within a category while 
setting standards.
    In promulgating a MACT standard, the EPA must first calculate the 
minimum stringency levels for new and existing solid waste incineration 
units in a category, based on levels of emissions control achieved in 
practice by the subject units. The minimum level of stringency is 
called the MACT floor. Different approaches exist for determining the 
floors for new and/or existing sources. For new, modified, and 
reconstructed sources, CAA section 129(a)(2) provides that the ``degree 
of reduction in emissions that is deemed achievable . . . shall not be 
less stringent than the emissions control that is achieved in practice 
by the best controlled similar unit, as determined by the 
Administrator.'' Emissions standards for existing units may be less 
stringent than standards for new units, but CAA section 129(a)(2) 
requires that the standards ``shall not be less stringent than the 
average emissions limitation achieved by the best-performing 12 percent 
of units in the category.'' The MACT floors form the least-stringent 
regulatory option the EPA may consider in the determination of MACT 
standards for a source category and therefore cost is not a factor for 
consideration. As a part of the ``beyond-the-floor'' evaluation, the 
EPA must evaluate standards more stringent than the floor, which 
includes the consideration of the factors outlined in CAA section 
129(a)(2) including the costs, non-air quality health and environmental 
impacts, and energy requirements of more stringent controls. See also 
Nat'l Ass'n for Surface Finishing v. EPA, 795 F.3d 1, 5 (D.C. Cir. 
2015) (explaining in related context under CAA section 112(d)(2), the 
EPA's obligation to set more stringent ``beyond-the-floor'' standards 
if practicable).
    MACT analyses involve assessing emissions from the best-performing 
units in a source category. The assessment can be based on actual 
emissions data, knowledge of existing air pollution control in 
combination with actual emissions data, or other information such as 
state regulatory requirements that enable the EPA to estimate the 
performance of the regulated units. For each source category, the 
assessment involves a review of actual emissions data with an 
appropriate accounting for emissions variability. Other methods of 
estimating emissions can be used, provided that the methods can be 
shown to provide reasonable estimates of the actual emissions 
performance of a source or sources. Where there is more than one method 
or technology to control emissions, the analysis may result in several 
potential regulations (regulatory options), one of which is selected as 
MACT for each pollutant. Each regulatory option must be at least as 
stringent as the minimum-stringency floor requirements. The EPA must 
also examine, but is not necessarily required to adopt, more stringent 
beyond-the-floor regulatory options to determine MACT. Unlike with 
floor minimum stringency requirements, the EPA must consider various 
impacts of the more stringent regulatory options in determining whether 
MACT standards are to reflect beyond-the-floor requirements. If the EPA 
concludes that the more stringent regulatory options have unreasonable 
impacts, the EPA selects the floor-based regulatory option as MACT. If 
the EPA concludes that impacts associated with beyond-the-floor levels 
of control are acceptable given the emissions reductions achieved, the 
EPA selects those levels as MACT.
    Under CAA section 129(a)(2), for new sources, the EPA determines 
the best control currently in use for a given pollutant and establishes 
one potential regulatory option at the emission level achieved by that 
control, accounting for emissions variability. More stringent potential 
beyond-the-floor regulatory options might reflect controls used on 
other sources that could be applied to the source category in question. 
For existing sources, the EPA determines the average emissions 
limitation achieved by the best-performing 12 percent of units to form 
the floor regulatory option. Beyond-the-floor options reflect other 
controls capable of achieving better performance.
    As noted earlier in this preamble, CAA section 129(a)(5) requires 
the EPA to conduct a review of the standards at 5-year intervals and, 
in accordance with CAA sections 129 and 111, if appropriate, revise the 
standards. In conducting the 5-year review, the EPA assesses the 
performance of and variability associated with control measures 
affecting emissions performance at sources in the subject source 
category (including the installed emissions control equipment), along 
with recent developments in practices, processes, and control 
technologies, and determines whether it is appropriate to revise the 
NSPS and EG. This approach is consistent with the requirement that 
standards under CAA section 129(a)(3) ``shall be based on methods and 
technologies for removal or destruction of pollutants before, during or 
after combustion.'' We do not interpret CAA section 129(a)(5), together 
with CAA section 111, as requiring the EPA to recalculate MACT floors 
in connection with this 5-year review.\4\ This general approach is 
similar to the approach taken by the EPA in periodically reviewing CAA 
section 111 standards, which, under CAA section 111(b)(1)(B), requires 
the EPA, except in specified circumstances, to review NSPS promulgated 
under that section every eight years and to revise the standards if the 
EPA determines that it is appropriate to do so.
---------------------------------------------------------------------------

    \4\ Elsewhere in the CAA, including under CAA section 112(d)(6), 
the EPA is also obliged to undertake periodic reviews. Although the 
nature or scope of the periodic review under CAA section 112(d)(6) 
is different than under CAA section 129(a)(5), it may be worth 
noting that, even under CAA section 112(d)(6), the EPA is not 
obligated to recalculate MACT floors in the course of a periodic 
review. NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008); Nat'l 
Ass'n for Surface Finishing v. EPA, 795 F.3d 1, 7-9 (D.C. Cir. 
2015).

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

[[Page 4249]]

B. What is the regulatory background for this source category?

    In December 1995, the EPA adopted EG (40 CFR part 60, subpart Cb) 
and NSPS (40 CFR part 60, subpart Eb) \5\ for large MWC units pursuant 
to CAA section 129. As stated earlier in section I.A.1 of this 
preamble, large MWC units have a combustion capacity greater than 250 
tpd of MSW. Both the EG and NSPS require compliance with emission 
limitations that reflect the performance of MACT. The 1995 NSPS apply 
to new large MWC units which commenced construction, were modified, or 
were reconstructed after September 20, 1994. The 1995 EG apply to 
existing large MWC units which commenced construction on or before 
September 20, 1994. The 1995 EG required that emission control 
retrofits be completed by December 2000. Retrofits of controls at 
existing large MWC units were completed on time (by December 2000) and 
were highly effective in reducing emissions of most CAA section 129 
pollutants. Relative to a 1990 baseline, the EG reduced organic 
emissions (PCDD/PCDF) by more than 99 percent, metal emissions (Cd, Pb, 
and Hg) by more than 93 percent, and acid gas emissions (HCl and 
SO2) by more than 91 percent. While NOX is also 
regulated under the 1995 EG and NSPS, the emissions reductions for 
NOX were relatively modest compared to the other CAA section 
129 pollutants.
---------------------------------------------------------------------------

    \5\ Note that on February 11, 1991, Subpart Ea was promulgated 
that applies Standards of Performance to MWCs which commenced 
construction after December 20, 1989, and on or before September 20, 
1994.
---------------------------------------------------------------------------

    The CAA requires review of these standards at 5-year intervals and, 
in 2006, amendments to the 1995 standards were promulgated. In the 2006 
final rule, titled ``Standards of Performance for New Stationary 
Sources and Emission Guidelines for Existing Sources: Large Municipal 
Waste Combustors'' (71 FR 27324, May 10, 2006), revisions to the 
emission limits and compliance testing provisions were made to reflect 
the actual performance achieved by existing MWCs and to reflect 
improvements in CEMS data performance and reliability.
    Following promulgation of the 2006 rulemaking, environmental groups 
filed a petition for review in the D.C. Circuit challenging the 
rulemaking. The petitioners challenged the MACT floor limits which the 
EPA promulgated in 1995. In light of then-recent precedents casting 
doubt on the soundness of MACT floors derived in part from state-issued 
air permits,\6\ as the 1995 MACT floors for large MWCs were, the EPA 
sought a voluntary remand of the 2006 rule. In its remand motion, the 
EPA announced its intention to grant the environmental groups' 
administrative petition to revisit the 1995 MACT floors and reevaluate 
the 2006 rule as necessary to comport with any revisions. The D.C. 
Circuit issued an order granting the EPA's request for a remand in 
2008, which directed EPA to review its 2006 rulemaking. Order, Sierra 
Club v. EPA, No. 06-1250 (D.C. Cir. filed Feb. 15, 2008).
---------------------------------------------------------------------------

    \6\ Specifically, the petitioners pointed to a 2004 decision 
from the D.C. Circuit, which remanded MACT floors established for 
existing small MWCs derived from state-issued permit limits because 
the Court found the EPA did not fulfill the requirement of CAA 
section 129(a)(2) in setting the floors. See Northeast Maryland 
Waste Disposal Authority v. EPA, 358 F.3d 936 (D.C. Cir. 2004). 
Additionally, the EPA noted in its motion for a voluntary remand 
that since the time the EPA finalized the 2006 rulemaking, the D.C. 
Circuit issued three decisions that were relevant to rules 
promulgated under sections 112 and 129 of the CAA, since the floor 
setting requirements in section 129 are essentially equivalent to 
those under section 112. See Sierra Club v. EPA, 479 F.3d 875 (D.C. 
Cir. Mar. 13, 2007) (vacating the EPA's regulations setting national 
emission standards for brick and clay ceramics kilns under Section 
112); Natural Resources Defense Council v. EPA, 489 F.3d 1250 (D.C. 
Cir. June 8, 2007) (vacating the EPA's regulations setting national 
emission standards under section 112 for hazardous air pollutants 
from industrial, commercial, and institutional boilers and process 
heaters and the EPA's regulations under section 129 defining the 
term ``commercial and industrial solid waste incineration unit''); 
Natural Resources Defense Council v. EPA, 489 F.3d 1364 (D.C. Cir. 
June 19, 2007) (vacating portions of an EPA rule promulgated under 
CAA section 112 regulating hazardous air pollutants from the 
manufacture of plywood and composite wood products).
---------------------------------------------------------------------------

C. What data collection activities were conducted to support this 
action?

    The majority of the data for addressing the MACT remand come from 
source inventory information from the original 1995 rulemaking docket 
and compliance test information compiled primarily from 2000 to 2009. 
This data set builds upon initial compliance data and inventory 
information collected in 2000. Starting with initial 2000 compliance 
data,\7\ Microsoft Excel spreadsheet template files were created to 
compile compliance data for the following years. These spreadsheet 
templates, or load sheets, were distributed to EPA regional contacts 
for the regions where a large MWC was being operated. The load sheets 
were distributed in early 2008, with most of the responses being 
completed and returned at some point during the year. Usually, EPA 
regional office contacts or state personnel completed the load sheets, 
but occasionally corporate contacts would provide the information. 
Sometimes, copies of compliance test reports and annual reports were 
submitted instead of load sheets. In these cases, data were extracted 
from the test report and entered into a load sheet for the unit or 
directly entered into the large MWC database records. The database of 
emissions data is available in the docket for this action.
---------------------------------------------------------------------------

    \7\ Bradley Nelson and Can Kuterdam, Alpha-Gamma Technologies, 
Inc., to Walt Stevenson, U.S. EPA. ``Performance/Test Data for Large 
Municipal Waste Combustors (MWCs) at MACT Compliance (Year 2000 
Data). June 18, 2002. EPA Air Legacy Docket A-90-45, Item VIII-B-4.
---------------------------------------------------------------------------

D. What other relevant background information and data are available?

    In addition to the compliance data compiled in 2009, data gaps for 
newer large MWC facilities were filled by downloading publicly 
available permit applications, permits, and test reports from State 
environmental data website portals to establish baseline emission 
estimates and air pollution controls currently in place for each unit. 
The EPA also conducted a site visit to the most recently constructed 
large MWC facility in the United States, where the only domestic MWC 
units with selective catalytic reduction (SCR) technology to control 
NOX emissions are operated. The site visit report and 
memorandum documenting the review and supporting information are 
available in the docket for this action.
    Finally, information and analyses from a separate rulemaking, the 
Good Neighbor Plan,\8\ were instrumental in the review of the large MWC 
NSPS and EG. Specifically, the 5-year review used information on 
performance, technical feasibility, and cost considerations for 
advanced selective noncatalytic reduction (ASNCR) and low 
NOX (LNTM) controls that can be retrofitted onto 
existing MWC units, as well as information on SCR controls for new 
units.
---------------------------------------------------------------------------

    \8\ See 88 FR 36654 (June 5, 2023).
---------------------------------------------------------------------------

E. How does the EPA perform the 5-year review?

    In conducting 5-year reviews under CAA section 129(a)(5), the EPA 
assesses the performance of, and variability associated with, control 
measures affecting emissions performance at sources in the subject 
source category (including the installed emissions control equipment), 
along with developments in practices, processes, and control 
technologies. For development of this proposed rule, the EPA reviewed 
available performance data for large MWC units. In reviewing the 
standards based on currently available emissions information, we

[[Page 4250]]

addressed the CAA section 129(a)(5) review's goals of assessing the 
performance efficiency of the installed equipment and ensuring that the 
emission limits reflect the performance of the technologies that 
sources are using to comply with MACT standards. In addition, we 
considered whether new technologies, processes, and improvements in 
practices have been demonstrated at sources subject to the 2006 large 
MWC rule. Our review evaluates implementation of the existing 
standards, which includes analysis of compliance data and 
identification of control and/or monitoring technologies trends that 
have occurred since the MACT standards were promulgated and previous 5-
year reviews were conducted. Where we identify potential trends or 
developments that ``indicate that emission limitations and percent 
reductions beyond those required by the standards . . . are achieved in 
practice,'' \9\ we analyzed their technical feasibility, estimated 
costs, energy implications, and non-air environmental impacts. We also 
consider the emission reductions associated with each development. This 
analysis informs our decision on whether to revise the emissions 
standards to reflect emission limitations ``achieved in practice.'' In 
addition, we consider the appropriateness of applying controls to new 
sources versus retrofitting existing sources. We consider any of the 
following to be a potential development:
---------------------------------------------------------------------------

    \9\ CAA section 129(a)(5) relies on CAA section 111 for 
requirements for 5-year review: ``. . . the Administrator shall 
review, and in accordance with this section and section 7411 of this 
title, revise such standards and requirements.'' CAA section 
111(b)(1)(B) states the following: ``When implementation and 
enforcement of any requirement of this Act indicate that emission 
limitations and percent reductions beyond those required by the 
standards promulgated under this section are achieved in practice, 
the Administrator shall, when revising standards promulgated under 
this section, consider the emission limitations and percent 
reductions achieved in practice.''
---------------------------------------------------------------------------

     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards or previous 5-year reviews.
     Any improvements in add-on control technology or other 
equipment that were considered during development of the original MACT 
standards or previous 5-year reviews and could result in additional 
emissions reduction.
     Any significant changes in the cost (including cost-
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original MACT standards or 
during previous 5-year reviews).

F. What outreach and engagement did the EPA conduct?

    There has been significant public interest in large MWC facilities 
due to concerns regarding impacts of emissions from these sources. In 
developing this proposed rule, the EPA conducted pre-proposal outreach 
activities with communities with environmental justice (EJ) concerns, 
as well as states and tribes. On December 6, 2022, a pre-proposal 
roundtable was conducted with communities to present background 
information on the industry and plans for the rulemaking, and to 
address questions. The EPA emailed information to roundtable 
stakeholders explaining how to comment on the non-regulatory docket 
established to solicit public input on the Agency's efforts to review 
and revise the large MWC emission standards. This information was sent 
to tribal nations, small businesses, and communities with EJ concerns 
via existing listservs on March 13, 2023.\10\ The EPA also conducted a 
public roundtable on March 20, 2023 for members of communities with EJ 
concerns and their representatives. Additionally, the EPA held a 
consultation meeting with the Intergovernmental Association and other 
Unfunded Mandate Reform Act (UMRA) stakeholders on March 16, 2023, to 
discuss the impact this rulemaking will have on operators of large 
MWCs, including units that are owned and operated by state and local 
entities.
---------------------------------------------------------------------------

    \10\ Information submitted to the pre-proposal non-regulatory 
docket at Docket ID No. EPA-HQ-OAR-2022-0920 is not automatically 
part of the proposal record. For information and materials to be 
considered in the proposed rulemaking record, it must be resubmitted 
in the rulemaking docket at EPA Docket ID No. EPA-HQ-OAR-2017-0183.
---------------------------------------------------------------------------

III. Analytical Results and Proposed Decisions

A. What are the results and proposed decisions based on our 5-year 
review and response to the voluntary MACT floor remand, and what is the 
rationale for those decisions?

1. Proposed Limits
    In this action, the EPA is reevaluating the initial MACT standards 
established in 1995 for large MWCs pursuant to our 2008 request to the 
D.C. Circuit for a voluntary remand and conducting the 5-year review of 
large MWC under CAA section 129(a)(5). As part of this process, we 
considered four scenarios for setting new EG and NSPS emission limits 
based on the EPA's obligations to reevaluate MACT standards established 
in 1995 and to conduct the 5-year review under CAA section 129(a)(5). 
As part of EPA's MACT floors reevaluation, the Agency first must 
consider best performing units to establish MACT floors limits, and 
then further consider whether additional beyond-the-floor controls are 
appropriate. As part of the 5-year review, the EPA must further 
consider whether additional controls are appropriate given improvements 
in pollution controls. Accordingly, the EPA undertook the following 
analyses to identify potential regulatory approaches: (1) determined 
the MACT floor limits for all pollutants, (2) determined the beyond-
the-floor based limits for all pollutants, (3) considered a combination 
of both MACT floor limits and 5-year review limits depending on the 
pollutant, and (4) further considered a combination of beyond-the-floor 
and 5-year review limits depending on the pollutant. Methodologies and 
rationale used to determine these limits are discussed in further 
detail in sections III.A.2 and 3 below. For reasons discussed later in 
this section of the preamble, the EPA is proposing the third scenario, 
which includes MACT floor limits for all pollutants except for 
NOX. The proposed limits for NOX reflect the 
results of the 5-year review. Tables 2 and 3 of this preamble present 
the proposed EG and NSPS emission limits for large MWCs, respectively. 
Current emission limits (from the 2006 rule) for existing and new units 
are provided for comparison. NOX and CO limits were assessed 
by subcategories determined by combustor type, including mass burn 
waterwall (MB/WW), mass burn rotary combustor (MB/RC), refuse-derived 
fuel stoker (RDF/S), RDF spreader stoker fixed floor/100 percent coal 
capable and RDF semi-suspension/wet RDF process conversion (RDF/SS), 
and RDF/fluidized bed combustion (RDF/FBC).

[[Page 4251]]



               Table 2--Comparison of Existing Source Limits for 2006 Large MWC Rule and the Proposed Emission Limits for Existing Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              2006 EG                     Proposed subcategory EG limits
                 Pollutant                          Units of measure         (current)  ----------------------------------------------------------------
                                                                               limits       MB/WW        MB/RC        RDF/S        RDF/SS      RDF/FBC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cd.........................................  ug/dscm @7 percent O2........           35                                1.5
Pb.........................................  ug/dscm @7 percent O2........          400                                 56
PM.........................................  mg/dscm @7 percent O2........           25                                7.4
Hg.........................................  ug/dscm @7 percent O2........           50                                 12
PCDD/PCDF..................................  ng/dscm @7 percent O2........    \b\ 30/35                                7.2
HCl........................................  ppmdv @7 percent O2..........           29                                 13
SO2........................................  ppmdv @7 percent O2..........           29                                 20
NOX \a\....................................  ppmdv @7 percent O2..........  \c\ 180-250                                110
                                                                                        ----------------------------------------------------------------
CO.........................................  ppmdv @7 percent O2..........   \d\ 50-250      \e\ 100          110          110      \e\ 250          110
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ NOX limit based on the 110 ppm (24-hour) NOX limit being finalized under National Ambient Air Quality Standards (NAAQS). Units equipped with SCR
  devices will be subject to their currently permitted limit of 50 ppm.
\b\ 30 ng/dscm for fabric filter equipped MWC units and 35 ng/dscm for electrostatic precipitator-equipped MWC units.
\c\ Range in limits based on combustor type. MB/WW (205); RDF (250); MB/RC (210); RDF/FBC (180).
\d\ Range in limits based on combustor type. MB/WW (100); MB/RC (250); RDF/S (200); RDF/SS (250); RDF/FBC (200); modular starved air or modular excess
  air (50).
\e\ Reevaluated MACT floor limit was less stringent than current limit, so is not proposed to change.


    Table 3--Comparison of New Source Limits for 2006 Large MWC Rule and the Proposed Emission Limits for New
                                                     Sources
----------------------------------------------------------------------------------------------------------------
                                                      2006 NSPS          Proposed subcategory NSPS limits
           Pollutant              Units of measure    (current)  -----------------------------------------------
                                                        limits         MB/WW           MB/RC           RDF/S
----------------------------------------------------------------------------------------------------------------
Cd.............................  ug/dscm @7 percent           10                        1.1
                                  O2.
Pb.............................  ug/dscm @7 percent          140                        13
                                  O2.
PM.............................  mg/dscm @7 percent           20                        4.9
                                  O2.
Hg.............................  ug/dscm @7 percent           50                        6.1
                                  O2.
PCDD/PCDF......................  ng/dscm @7 percent           13                        1.8
                                  O2.
HCl............................  ppmdv @7 percent             25                        7.8
                                  O2.
SO2............................  ppmdv @7 percent             30                        14
                                  O2.
NOX \a\........................  ppmdv @7 percent            150                        50
                                  O2.
                                                                 -----------------------------------------------
CO.............................  ppmdv @7 percent     \b\ 50-150                16                           100
                                  O2.
----------------------------------------------------------------------------------------------------------------
\a\ NOX limit based on 50 ppm (24 hour) permitted limit for units currently equipped with SCR control devices.
\b\ Range in limits based on combustor type. MB/WW (100); RDF/S (150); Modular starved air or modular excess air
  (50).

2. MACT Floor Assessment
    To correct our initial analysis of MACT floors undertaken in 1995, 
the EPA proposes to recalculate the large MWC MACT floors to account 
for the development of caselaw calling into question the establishment 
of these standards based on state-issued permit levels where there is 
no evidence that the permit levels reflect the performance of the best 
performing sources. As discussed above, following a series of D.C. 
Circuit cases which called into question the use of state permitting 
data for establishing MACT floors,\11\ the EPA sought and was granted a 
voluntary remand of the 2006 revisions to the large MWC regulations in 
response to a petition for reconsideration from environmental groups to 
re-evaluate the 1995 MACT floors, which were also based on emission 
limits established in state-issued permits (60 FR 65387, December 19, 
1995). In its motion for a voluntary remand, the EPA explained that it 
intended to ``re-analyze the floors in the 1995 rule,'' \12\ and 
``revisit the data and information used in the 1995 rule, as well as 
obtain additional data, to determine whether the 1995 floors need to be 
revised.'' \13\ However, in reviewing the data and information the EPA 
utilized in calculating the 1995 MACT floors, the EPA determined that 
it does not have sufficient data from that time period to characterize 
the performance of all units that is necessary to evaluate MACT floors.
---------------------------------------------------------------------------

    \11\ See note 6, supra.
    \12\ EPA Motion for Voluntary Remand at 8, Sierra Club v. EPA, 
no. 06-1250 (D.C. Cir. filed Nov. 9, 2007).
    \13\ Id. at 10.
---------------------------------------------------------------------------

    We are accordingly proposing to base our calculation of the MACT 
floors on additional emissions data from sources in the large MWC 
source category. In recalculating the MACT floors to correct for errors 
in our initial analysis, however, EPA is assessing the state of the 
industry at the time limits were first calculated for large MWCs in 
1995. Given the specifics of the history of the regulation of this 
source category, the EPA views this as an appropriate approach to 
establish MACT floors that reflect the emission levels actually 
achieved by the best-performing sources using the maximum achievable 
control technology before sources in the category first complied with 
the 1995 standards. The EPA proposes utilizing 1995 performance levels 
to re-establish MACT floor requirements appropriately balances 
competing interest in this rulemaking, by recognizing on one hand that 
LMWC facilities have taken steps to reduce emissions since the EPA 
first promulgated 1995 standards, and on the other hand the EPA's 
obligation to ensure MACT floor standards are set correctly for each 
source category regulated under CAA section 129. To do this, however, 
the EPA finds it is necessary to utilize a different dataset to 
recalculate new MACT floors than the

[[Page 4252]]

one used to set the initial MACT floors in 1995.
    In a related context, for hospital, medical, and infectious waste 
incinerators (HMIWI) regulated under CAA section 129, the EPA addressed 
a remand from the D.C. Circuit to provide further explanation of the 
EPA's reasoning in determining MACT floors for new and existing HMIWI. 
See 74 FR 51368 (October 6, 2009). In that case, after the original 
MACT floors went into effect for HMIWI, approximately 94% of HMIWI 
units shutdown, and an additional 3% of units obtained exemptions from 
the EPA's regulations. 72 FR 5510, 5518 (proposed February 6, 2007). 
Because of these significant changes in the regulated industry, in 
addressing the D.C. Circuit's remand, the EPA found it was not 
confident in using much of the same data relied upon in setting the 
original MACT floors in part because data were unavailable from the 
many units that shut down following promulgation of the original 
standards. The EPA instead found ``the best course of action [was] to 
re-propose a response to the remand based on data from the 57 currently 
operating HMIWI.'' 73 FR 72962, 72970 (proposed December 1, 2008). In 
reviewing the EPA's decision in how it recalculated MACT floors for 
HMIWI, the D.C. Circuit found, ``[w]hen the EPA determined that its 
regulation rested on unreliable data and that it had to reset the 
floors, the agency was functionally regulating on a blank slate even 
though the regulation continued to remain on the books.'' Medical Waste 
Institute and Energy Recovery Council v. E.P.A., 645 F.3d 420 (D.C. 
Cir. 2011).
    Similar to the D.C. Circuit's finding in Medical Waste Institute, 
the EPA proposes here it is functionally establishing new MACT floors 
for large MWCs on a blank slate. However, unlike the HMIWI rulemaking, 
the EPA has not seen significant retirements in the large MWC industry 
since the EPA first introduced standards pursuant to CAA section 129 in 
1995, and the industry today is comprised of largely the same set of 
units that were operating before the original MACT floors went into 
effect. Instead of retirements, the majority of the industry undertook 
the installation of air pollution control devices and made other 
improvements to meet the 1995 standards. Therefore, the EPA proposes 
for recalculating MACT floors for LMWCs, because the industry today is 
comprised of largely the same set of units that were operating in 1995, 
that the EPA is able to calculate revised MACT floors appropriate for 
the current LMWC population based on the industry's 1995 performance 
level.
    In calculating MACT floors, for existing sources, the CAA requires 
that MACT limits be no less stringent than the average emissions 
limitation achieved by the best-performing 12 percent of units in a 
source category. The EPA must determine some measure of the average 
emissions limitation achieved by the best-performing 12 percent of 
units to form the floor regulatory option. For new sources, the CAA 
requires that MACT limits be no less stringent than the emissions 
control achieved in practice by the best-controlled similar unit.
    Our first step in calculating the MACT floor limits based on the 
EPA's proposed rationale was to identify the population of units 
operating at the time of the original emission guidelines development 
(1990), then use corresponding compliance data reported from 2000 
through 2009 \14\ to rank units by performance for each pollutant. 
Compliance data were adjusted to account for supplemental control from 
air pollution control device (APCD) configurations that were not in 
place prior to 1995. These control adjustments were made by assigning 
default control efficiencies to each APCD configuration for each 
pollutant, back calculating an ``uncontrolled'' emissions value from 
the post-retrofit data, then applying the control efficiencies 
corresponding to pre-retrofit configurations to estimate emissions that 
would more accurately represent the performance level of units 
operating in 1990.
---------------------------------------------------------------------------

    \14\ The Large MWC 2009 Database is located in the docket for 
this rulemaking in Microsoft Access database format. The memorandum 
documenting the database contents and creation is also available in 
the docket.
---------------------------------------------------------------------------

    Adjusted data were ranked, and top performing units were identified 
for each pollutant and any applicable subcategories. Then, 
corresponding emissions data were compiled and analyzed to determine 
the average performance of those units, with an appropriate accounting 
for emissions variability, to establish MACT floor emission limits. 
Separate methodologies were used for pollutants having stack test data 
(Cd, Pb, Hg, PM, HCl, and PCDD/PCDF) and pollutants having CEMS data 
(CO, NOX, and SO2).
    For each stack test pollutant, a statistical analysis was performed 
on annual averages of screened run data from the 2000 to 2009 dataset 
to determine an upper prediction limit (UPL). For EG limits, average 
annual run data corresponding to the top 12 percent of units were used, 
and for NSPS limits, average annual run data for the single top 
performer was used.\15\ The UPL is appropriate when data are not 
available for every source in a population of interest and a 
``prediction'' element is warranted in the final floor value. This is 
the case for the 1990 population of large MWCs because several units 
shut down before compliance data were collected. The EPA's most recent 
UPL template, released in January 2022, was used to conduct the 
analysis. UPL results were rounded up to two significant figures.
---------------------------------------------------------------------------

    \15\ For PCDD/PCDF, the top performing unit only had enough 
reported data to derive two annual averages. In this case, because 
the UPL template can only accommodate data sets of n >= 3, unit run 
data were used instead.
---------------------------------------------------------------------------

    UPL results and the derived EG and NSPS MACT floor limits are 
presented in Table 4 of this preamble. Additional discussion of the 
methodology, detailed results, and a copy of the UPL template can be 
found in the docket.\16\
---------------------------------------------------------------------------

    \16\ See memorandum ``MACT Floor Calculations for Large 
Municipal Waste Combustor Units'' available at Docket ID. No. EPA-
HQ-OAR-2017-0183.

[[Page 4253]]



                   Table 4--Large MWC MACT Floor EG and NSPS Limits for Stack Test Pollutants
----------------------------------------------------------------------------------------------------------------
                                                    EG MACT floor calculations     NSPS MACT floor calculations
                                   Units  (@7    ---------------------------------------------------------------
           Pollutant               percent O2)                      MACT floor                      MACT floor
                                                    UPL result         limit        UPL result         limit
----------------------------------------------------------------------------------------------------------------
Cd............................  ug/dscm.........            1.44             1.5           0.492         \a\ 1.1
Pb............................  ug/dscm.........           55.65              56           12.19              13
PM............................  mg/dscm.........            7.36             7.4            4.81             4.9
Hg............................  ug/dscm.........          11.997              12            6.07             6.1
PCDD/PCDF.....................  ng/dscm.........            7.18             7.2            1.73         \b\ 1.8
HCl...........................  ppmdv...........           12.92              13           7.799             7.8
----------------------------------------------------------------------------------------------------------------
\a\ Calculated results were less than the representative detection level (RDL), so the MACT floor limit has been
  set at Cd's 3 times RDL value of 1.1 ug/dscm.
\b\ The top performer for PCDD/PCDF only had two years of data. The UPL requires at least three data points, so
  instead of annual averages, individual test runs were used in this case.

    Unlike stack test pollutants, there are no individual run data for 
CEMS pollutants. Instead, data for CO, NOX, and 
SO2 are collected continuously, and available data comprise 
only peak annual values for which the current rule requires reporting. 
Although upper limit statistical approaches were initially considered 
for establishing MACT floor limits, it was ultimately determined that 
the data already account for emissions variability, since the annual 
peak 24-hour or 4-hour average has been selected from the year's CEMS 
data and represents only the highest end of readings for the year. 
Therefore, no
statistical calculations to account for variability are warranted for 
the CEMS pollutant data sets. The limits were reevaluated simply by 
averaging annual peak CEMS data corresponding to the top performers for 
each pollutant and applicable subcategory. For NOX and CO, 
separate NSPS limits were calculated for only two subcategories, MB/WW 
and RDF. They were not broken down further, as was done for EG limits, 
because the MB/RC, RDF/SS, and RDF/FBC subcategories represent single, 
unique facilities with unit designs that likely will not be used in any 
future large MWC units. For NSPS purposes, we assumed the overarching 
MB or RDF subcategories will represent performance of any units built 
in the future.
---------------------------------------------------------------------------

    \17\ See memorandum ``MACT Floor Calculations for Large 
Municipal Waste Combustor Units'' available at Docket ID. No. EPA-
HQ-OAR-2017-0183.
---------------------------------------------------------------------------

    As with the UPL results for stack test pollutants, resulting 
averages for CEMS pollutants were rounded up to two significant 
figures. In cases where results were greater (less stringent) than the 
current large MWC EG limit, the current limit was retained as the MACT 
floor limit.
    Averages and subsequent MACT floor EG and NSPS limits are 
summarized in Tables 5 and 6 of this preamble, respectively. Additional 
discussion of the methodology, detailed results, and a copy of the UPL 
template can be found in the docket.\17\

                                                                   Table 5--Large MWC MACT Floor EG Limits for CEMS Pollutants
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                             EG MACT floor calculations
                                                                                   -------------------------------------------------------------------------------------------------------------
                   Pollutant                           Units  (@7 percent O2)                  Average of annual peak CEMS data                               MACT floor limit
                                                                                   -------------------------------------------------------------------------------------------------------------
                                                                                      MB/WW      MB/RC       RDF       RDF/SS    RDF/FBC     MB/WW      MB/RC       RDF       RDF/SS    RDF/FBC
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SO2............................................  ppmdv............................                          19.33
                                                                                       20
                                                                                   -------------------------------------------------------------------------------------------------------------
NOX............................................  ppmdv............................     226.52     142.25         157.29            290.83    \a\ 205        150           160            \a\ 180
                                                                                                         ----------------------                                 ----------------------
CO.............................................  ppmdv............................     168.52     109.92     102.14     818.90     101.40    \a\ 100        110        110    \a\ 250        110
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Calculated limit was less stringent than current limit so kept at current limit.


                          Table 6--Large MWC MACT Floor NSPS Limits for CEMS Pollutants
----------------------------------------------------------------------------------------------------------------
                                                                   NSPS MACT floor calculations
                                                 ---------------------------------------------------------------
                                   Units  (@7      Average of annual peak  CEMS          MACT floor limit
           Pollutant               percent O2)                 data              -------------------------------
                                                 --------------------------------
                                                        MB              RDF             MB              RDF
----------------------------------------------------------------------------------------------------------------
SO2...........................  Ppmdv...........               13.96
                                               14
                                                 ---------------------------------------------------------------
NOX...........................  Ppmdv...........          130.50          154.46             140         \a\ 150
CO............................  Ppmdv...........           15.65           99.03              16             100
----------------------------------------------------------------------------------------------------------------
\a\ Calculated limit was less stringent than current limit so kept at current limit.

3. Beyond-the-Floor and 5-Year Review Results and Selection of Proposed 
Emission Limits
    For assessing beyond-the-floor options at the time of the original 
rulemaking (i.e., as companion to addressing the remand of the original 
rule's MACT floors), the EPA recognizes that the majority of large MWC 
units have since been equipped with air pollution control devices that 
would represent state-of-the-art technology in the 1990s, such as spray 
dryer absorbers (SD) for HCl and SO2; fabric filters for PM, 
Cd, and Pb; activated carbon

[[Page 4254]]

injection (ACI) for Hg and PCDD/PCDF; and selective noncatalytic 
reduction (SNCR) for NOX emissions control. Therefore, to 
represent beyond-the-floor emission limits for existing sources 
numerically, we have assumed that the new source MACT floor (i.e., 
emissions control achieved in practice by the best controlled similar 
unit) as the emission limit applied to existing sources would represent 
the beyond-the-floor option in the reevaluation of the 1995 standards.
    To assess additional control options currently in use in completion 
of the 5-year review pursuant to CAA section 129(a)(5), the EPA 
assessed the performance of, and variability associated with, control 
measures affecting emissions performance at large MWC sources 
(including the installed emissions control equipment), and recent 
developments in practices, processes, and control technologies. As 
evidenced by the recently finalized Good Neighbor Plan rulemaking,\18\ 
there are cost-effective advanced NOX control technologies 
available for retrofit to existing large MWC units, namely ASNCR and 
Covanta's LNTM Technology. Furthermore, for new sources, SCR 
has been installed on the most recently constructed large MWC facility 
(comprising three units) in the United States, so the permitted 
emission limit for this SCR-equipped facility represents the 5-year 
review-based standard for new sources. Neither of these control options 
were being applied to large MWC units in the 1990s, and development and 
commercial application of LN technology and ASNCR did not occur until 
the 2000s. To reflect that these technologies are now available and 
economically and technically viable, the EPA determined that the 
beyond-the-floor option for NOX did not reflect the current 
state of the control technologies. Instead, the third and fourth 
scenarios consider the NOX control technologies as 5-year 
review options for consideration and combine this with either MACT 
floor or beyond-the-floor controls for the other pollutants. In other 
words, the third scenario consists of MACT floor emission limits for 
all pollutants except NOX, which is being proposed as a 5-
year review emission limit. The fourth scenario consists of beyond-the-
floor emission limits for all pollutants except NOX, which 
is proposed as a five-year review emission limit. As discussed further 
at the end of this section, as part of the five-year review, the EPA 
also reviewed and is taking comment on whether more recent improvements 
present additional control options for other pollutants.
---------------------------------------------------------------------------

    \18\ See 88 FR 36654 (June 5, 2023). The Good Neighbor Plan 
established a combination approach to secure reductions of ozone-
forming emissions of NOX from power plants and industrial 
facilities in nine large industries. This included NOX 
emissions limits and compliance assurance requirements for large MWC 
units operating within the Ozone Transport Region, which applies to 
28 MWC facilities with a total of 80 units, across 20 states. In 
promulgating these requirements, the EPA found costs effectiveness 
values to install applicable control technologies were in line with 
control technology costs for other large industry sectors covered by 
the rule.
---------------------------------------------------------------------------

    The estimated cost impacts and emissions reductions of the MACT 
floor, beyond-the-floor,\19\ MACT floor/5-year review, and beyond-the-
floor/5-year review are presented in sections IV.D. and IV.B of this 
preamble, respectively. Based on our analyses and the findings of the 
Good Neighbor Plan, selecting the MACT floor/5-year review scenario 
provides the most cost-effective means to maximize emission reductions. 
As presented in section IV.B of this preamble, the MACT floor, the MACT 
floor/5-year review scenario, and beyond-the-floor/5-year review 
scenarios are expected to result in 5,020, 14,200 and 16,800 tons per 
year of emissions reductions of regulated pollutants, respectively. 
Therefore, it is evident that the emissions reductions for the 5-year 
review scenarios are significantly greater than the MACT floor 
(approximately 11,000 tons per year more), while the beyond-the-floor 
scenario only adds 2,600 tons per year in incremental emissions 
reduction above the MACT floor/5-year review scenario. As discussed 
earlier, cost is not a consideration for the MACT floor level of 
control, but consideration of the costs, including incremental cost-
effectiveness, of the 5-year review and beyond-the-floor scenarios is 
allowed. In section IV.D of this preamble the cost impacts of each 
scenario assessments are presented. In reviewing the cost results, the 
MACT floor/5-year review scenario is just under $100 million per year 
in total annual costs (including annualized capital costs and operating 
and maintenance costs), while the beyond-the-floor/5-year review 
scenario is estimated to cost $582 million per year. From a cost-
effectiveness viewpoint, the MACT floor/5-year review scenario comes in 
at approximately $7,000 per ton emissions reduction, while the beyond-
the-floor/5-year review scenario, being over five times more costly 
with less incremental emissions reductions, results in a cost-
effectiveness estimates at approximately $35,000 per ton emissions 
reduction of regulated pollutants. Considering this, as mentioned 
above, the MACT floor/5-year review scenario provides the most cost-
effective means to maximize emissions reductions and this scenario is 
being proposed.
---------------------------------------------------------------------------

    \19\ As noted, the 5-year review scenario for NOX was 
notably cost-effective and technically feasible compared to the 
beyond-the-floor for NOX, so beyond-the-floor for all 
pollutants (scenario 2) was not evaluated for cost or air impacts.
---------------------------------------------------------------------------

    Selection of the MACT floor/5-year review scenario further 
recognizes that most sources have already been retrofitted with APCD 
that were considered to be state of the art for MWCs in the 1990s 
(i.e., spray dryers, fabric filters, activated carbon injection, and 
selective noncatalytic reduction). That is, other than NOX, 
most large MWC units have control devices in place to meet at least 
some of the standards, with options for incremental improvements being 
readily available through increased sorbent use, for example. The 
NOX control retrofits that are currently available (but were 
not in the 1990s) for most existing large MWCs appear to be cost 
effective (approximately $5,000 to $6,000 per ton). Except for very 
limited examples, these technologies appear to be, and in fact recently 
have been, technically feasible for several existing large MWC units 
currently operating in the U.S.
    As a result of the 5-year review, the EPA is proposing the 110 
parts per million (ppm) (24-hour) NOX limit finalized under 
the Good Neighbor Plan, based on the application of ASNCR or Covanta 
LNTM NOX technology. For this proposed action, 
the EPA has evaluated this limit for the full population of large MWCs, 
and the EPA finds that this limit is cost-effective for units outside 
of the Ozone Transport Region that are not covered by the Good Neighbor 
Plan.\20\
---------------------------------------------------------------------------

    \20\ In the Good Neighbor Plan, the EPA separately found this 
limit is cost-effective for units inside of the Ozone Transport 
Region. 88 FR 36654 (June 5, 2023).
---------------------------------------------------------------------------

    Unlike the Good Neighbor Plan, the EPA is not proposing a mechanism 
for existing large MWCs to request a case-by-case emission limit based 
on a demonstration that application of ASNCR and Covanta's 
LNTM Technology or any other NOX emission 
reduction technologies or measures is not technically feasible. This is 
because the EPA does not have the same ability to establish less 
stringent case-by-case emission limits under CAA section 129 standards, 
as it does under the ``good neighbor provision'' of CAA section 
110(a)(2)(D)(i)(I). We request comment on whether there are unique 
circumstances (e.g., combustor design/type) that render the proposed 
NOX emission limit technically infeasible and whether 
subcategorized emission

[[Page 4255]]

limits may be appropriate in certain instances.
    For new units, the EPA is proposing a NOX NSPS limit of 
50 ppm (24-hour), based on the permitted NOX limit for the 
only facility currently using SCR technology with an air-to-air heat 
exchanger providing flue gas reheat prior to entering the SCR reactor. 
This design can only be reasonably applied during construction of the 
unit, so retrofitting SCRs to other existing units would be technically 
infeasible and/or very costly if a supplemental burner is required to 
provide reheat. We are proposing to apply this limit to all new units.
    Aside from NOX, the only other potential improvements 
considered technically feasible for large MWCs as part of the 5-year 
review are circulating fluidized bed scrubbers (CFBS) for acid gas 
control and oxidation catalysts for CO control. Neither of these 
technologies appear to be in use on any large MWC units, but they have 
been included in construction permits for some large MWC unit projects 
that were never constructed. Like SCR, CO oxidation catalysts would be 
prohibitively costly to retrofit to existing large MWC units, as they 
would require new facility footprint space and flue gas routing to 
accommodate an entirely new piece of equipment in the air pollution 
control device system. However, new sources may consider their 
application to meet the proposed CO limit. For CFBS, theoretically 
existing acid gas control devices could be replaced with a CFBS in the 
same footprint (similar to electrostatic precipitator replacement with 
fabric filter devices for particulate control) to achieve slightly 
better acid gas control than spray dryer absorbers. There is no 
available cost algorithm specific to CFBS, but available information 
comparing technical and performance parameters of CFBS and spray dryer 
absorbers (SDAs) indicates that SDA costs might serve as a reasonable 
proxy for CFBS costs. Based on expected costs for spray dryer 
replacement (since direct CFBS cost data are unavailable), the EPA has 
estimated the emissions and cost impacts of setting the limits to a 
level that would most likely require most existing sources to retrofit 
with CFBS, and has determined that the marginal improvement in 
emissions performance compared to increased sorbent injection rates 
using existing controls is not cost effective (approximately $73,000 
per ton versus approximately $4,600 per ton). Further explanation is 
provided in the large MWC cost memorandum.\21\ Since we have no data 
demonstrating the technical feasibility on new or existing MWC units, 
we are not proposing standards based on any potential performance 
improvements of these technologies and are instead using the MACT floor 
calculations to establish EG and NSPS limits for existing and new 
units. We request comment on whether there are any large MWC units 
equipped with these technologies (i.e., CFBS and oxidation catalysts) 
and the performance and cost information of these controls.
---------------------------------------------------------------------------

    \21\ ``Compliance Cost Analyses for Proposed Large MWC Rule 
Amendments'' available at Docket ID. No. EPA-HQ-OAR-2017-0183.
---------------------------------------------------------------------------

B. What other actions are we proposing, and what is the rationale for 
those actions?

1. Changes to the Applicability Date of the 1995 Large MWC EG and NSPS
    In this proposal, large MWC units would be treated differently 
under the amended standards as proposed than they were under the 1995 
large MWC rule in terms of whether they are ``existing'' or ``new'' 
sources. Consistent with CAA section 129, new dates would define which 
units are considered new sources. Large MWC units that are currently 
subject to the NSPS would become existing sources under the proposed 
amended standards and would be required to meet the revised EG 
standards by the applicable compliance date for the revised guidelines. 
However, those units would continue to be NSPS units subject to the 
1995 large MWC rule until they become subject to the amended existing 
source standards. Large MWC units that commence construction after the 
date of this proposal, or for which a modification is commenced on or 
after the date 6 months after promulgation of the amended standards, 
would be new units subject to the NSPS emission limits. Units for which 
construction or modification is commenced prior to those dates would be 
existing units subject to the proposed EG. That is, under these 
proposed amendments, any large MWC units that commenced construction on 
or before January 23, 2024, or that are reconstructed or modified prior 
to the date 6 months after promulgation of any revised final standards, 
would be subject to the 1995 large MWC NSPS/1991 NSPS (Ea, as 
appropriate) until the applicable compliance date for the revised EG, 
at which time those units would become existing sources. Similarly, 
large MWC units subject to the EG under the 1995 large MWC rule would 
need to meet the revised EG by the applicable compliance date for the 
revised guidelines. Large MWC units that commence construction after 
January 23, 2024 or that are reconstructed or modified 6 months or more 
after the date of promulgation of any revised standards would have to 
meet the revised NSPS emission limits being added to 40 CFR part 60, 
subpart Eb within 6 months after the promulgation date of the 
amendments or upon startup, whichever is later.
    Due to the timing of the original promulgation of NSPS for this 
source category and the 1990 CAA Amendments, there is a second NSPS 
applicable to large MWCs for which some standards are still referenced 
in title V operating permits. Subpart Ea standards apply to units for 
which construction commenced after December 20, 1989, and on or before 
September 20, 1994. Due to the proposed resetting of the ``new'' and 
``existing'' definitions described above, any units that meet subpart 
Ea applicability would become existing units subject to 40 CFR part 60, 
subpart Cb once implemented through a state or Federal plan. As such, 
subpart Ea would no longer be necessary. We propose to ``reserve'' 40 
CFR part 60, subpart Ea NSPS standards once the revised EG emission 
limits are implemented (i.e., remove the current text of subpart Ea 
once it is no longer in use and maintain subpart Ea as a placeholder) 
and request comment on whether this future action would help or hinder 
implementation of the standards and any potential unintended 
consequences this could cause.
2. Proposed Removal of Alternative Percent Reduction Standards for Hg, 
HCl, and SO2 and Emissions Averaging Allowance for 
NOX
    In addition to the proposed emission limits discussed in section 
III.A of this preamble, we also propose to remove all alternative 
percent reduction standards that were allowed in the original 
rulemaking. Specifically, we are proposing to remove the 85 percent 
reduction allowed for Hg (NSPS and EG), the 95 percent allowed for HCl 
(NSPS and EG), and the 80 percent (NSPS) and 75 percent (EG) allowed 
for SO2. The percent reduction standards were introduced in 
1989 when MWCs were regulated under section 111 of the CAA. They were 
established in addition to numeric emission limits and offered as an 
alternative means of compliance. The rationale for removal of these 
alternative standards is twofold. First, the proposed reevaluation of 
the standards relies solely on the vast

[[Page 4256]]

amount of pollutant concentration data reported and compiled in the 
emissions database. There are not as much data available to evaluate 
for the alternative percent reduction standards, which increases the 
risk of mischaracterizing the emissions limitations achieved by the 
best-performing sources when using that data. Retaining the existing 
percent reduction alternatives could introduce a disconnect between the 
numeric reevaluated limits and the alternative percent reduction 
standards. Second, having a numeric concentration limit for these 
pollutants provides a level playing field for the environmental 
protection and health of the surrounding communities by preventing 
situations where a different concentration of pollutants is emitted 
from facility to facility or unit to unit. Most owners and operators 
can meet pollutant concentration limits and primarily use the 
concentration as their compliance target, with far fewer units emitting 
at much higher concentrations using the percent reduction allowance. 
For these reasons, we have determined that, at least for the large MWC 
source category, a single pollutant concentration limit is the most 
prevalent compliance standard and the most protective of the 
environment and human health for all communities where large MWCs 
operate. We request comment on the proposed removal of alternative 
percent reduction standards for Hg, HCl, and SO2 and on the 
proposed rationale for removal of these alternative standards.
    For similar reasons, we also propose to remove the NOX 
emissions averaging alternative provided in 40 CFR 60.33b(d)(1) of the 
EG. The EPA has observed that this alternative, which allows for 
emissions trading among large MWC sources, is scarcely used, if at all. 
Furthermore, the emissions averaging alternative is incompatible with 
the NOX emissions standards established under the Good 
Neighbor Plan,\22\ which are similarly being proposed as part of this 
rule's 5-year review process in light of cost-effective retrofit 
options available for increased NOX control at existing 
facilities. We understand that this provision may have been useful in 
the original 1995 rulemaking but have determined that it is no longer 
necessary to provide this allowance. We request comment on the proposed 
removal of the NOX emissions averaging alternative and on 
the proposed rationale for removal of this alternative standard.
---------------------------------------------------------------------------

    \22\ The Good Neighbor Plan did not establish an emissions 
trading program for non-power plant industries, including large 
MWCs, due to inadequate baseline data and other information that 
would be needed to develop emissions budgets. See 88 FR 36683 June 
5, 2023.
---------------------------------------------------------------------------

3. Proposed Changes to Startup, Shutdown and Malfunction Provisions
    In addition to the proposed actions described above, we are 
proposing additional revisions to the NSPS and EG. We are proposing 
revisions to the SSM provisions of the NSPS and EG in order to ensure 
that they are consistent with the decision in Sierra Club v. EPA, 551 
F. 3d 1019 (D.C. Cir. 2008), in which the court vacated two provisions 
that exempted sources from the requirement to comply with otherwise 
applicable CAA section 112(d) (or 129(a)(1)) emission standards during 
periods of SSM. While the Court's ruling did not specifically address 
the legality of source-category-specific SSM provisions adopted in the 
1995 large MWC rule, the decision calls into question the legality of 
those provisions. As such, the EPA is proposing to remove the exemption 
for SSM periods contained in the 1995 large MWC rule and the proposed 
emission standards summarized in this preamble would apply at all 
times.
    We are not proposing a separate emission standard for large MWC 
units that applies during periods of startup and shutdown. We 
determined that large MWC units will be able to meet the emission 
limits during periods of warmup and startup because most units use 
natural gas or clean distillate oil to warm up the unit and do not add 
waste until the unit has reached combustion temperatures during a brief 
startup period. Emissions from burning natural gas or distillate fuel 
oil would generally be significantly lower than from burning solid 
wastes for most pollutants, specifically those where compliance is 
measured using stack tests (e.g., Cd, Pb, Hg, PM, PCDD/PCDF, and HCl).
    Emissions during periods of shutdown are also generally 
significantly lower than emissions during normal operations because the 
materials in the incinerator are almost fully combusted before shutdown 
occurs. Furthermore, the approach for establishing MACT floors for 
large MWC units ranked individual MWC units based on actual performance 
for each pollutant and subcategory, with an appropriate accounting of 
emissions variability. Because we accounted for emissions variability 
and established appropriate averaging times to determine compliance 
with the standards, we believe we have adequately addressed any minor 
variability that may potentially occur during startup or shutdown. We 
request comment on the proposed removal of the exemption for startup 
and shutdown periods and the rationale for applying the proposed 
emission standards at all times.
    For NOX, SO2 and CO, where the current rule 
requires that a CEMS continuously measures the concentration, we are 
proposing to eliminate the exclusions of periods of warmup, startup, 
and shutdown from CEMS data averaging calculations present in the 1995 
large MWC rules and replace them with a monitoring and compliance 
demonstration approach used in the more recent CAA section 129 
rulemaking for CISWI NSPS and EG. First, we are proposing that CEMS 
data must be collected and reported whenever the large MWC unit is 
operating. Periods when the combustor is operating but no monitoring 
data are recorded due to monitor malfunctions would be considered 
deviations or violations.\23\ This is consistent with observed 
increased CEMS reliability (availability) experienced for CEMS monitors 
operated across multiple source categories, typically greater than 99 
percent, and the regulatory provisions currently associated with CEMS 
data availability.
---------------------------------------------------------------------------

    \23\ This excludes periods of required routine monitor 
calibrations or quality assurance/quality control periods.
---------------------------------------------------------------------------

    Secondly, CEMS data collected while the large MWC unit is warming 
up (no waste is introduced to the grate), starting up (warmup period is 
over and waste is first fed to the grate but not at steady state 
operation) and shutting down (waste is no longer being fed but is 
burning down on grate) will be flagged as warmup, startup, or shutdown 
period data. CEMS data collected during warmup, startup, or shutdown 
periods will be averaged at stack oxygen content and not corrected to 7 
percent oxygen, as are data during normal operations. This is 
consistent with the regulatory approach used for a subcategory of units 
in the CISWI (see 80 FR 3018, January 21, 2015) that are similar in 
type to large MWCs, where: ``[P]etitioners indicated that correcting CO 
concentration measurements to 7 percent oxygen is problematic during 
startup and shutdown periods when the flue gas oxygen content 
approaches the oxygen content of ambient air, especially with regard to 
the energy recovery unit (ERU) subcategory. Oxygen contents relatively 
close to ambient air are often maintained during combustion unit 
startup and shutdown in order to safely operate the unit, but, as a 
result, the corrected CO values during these periods are artificially 
inflated due to the oxygen correction

[[Page 4257]]

calculation.'' To resolve this issue in the CISWI rule, the EPA 
determined that the 7 percent oxygen correction would not be required 
for CEMS data collected during periods of startup and shutdown. We are 
proposing a similar approach here, where the CEMS data for the warmup 
period (no time limit specified, but we request comment on a 
recommended warmup period cutoff) and up to 3 hours of allowable 
startup or shutdown time per occurrence will be used to calculate 
rolling or block average values, but will be averaged in at stack 
oxygen content instead of at a 7 percent oxygen diluent cap. No changes 
to the current 4- or 24-hour averaging periods are proposed. Instead, 
we are requesting comment on whether we should adopt a 30-day hourly 
rolling average for demonstrating compliance for pollutants measured 
using continuous monitoring, similar to provisions that have been 
promulgated in many recent combustion standards, such as CISWI and the 
Mercury Air Toxics Standards (40 CFR part 63, subpart UUUU) and the 
National Emission Standards for Hazardous Air Pollutants for Major 
Sources: Industrial, Commercial and Institutional Boilers and Process 
Heaters (40 CFR part 63, subpart DDDDD), as examples (see further 
discussion on the averaging time for CEMS below).
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead, they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment. (40 CFR 60.2) 
(Definition of malfunction). The EPA interprets CAA section 129 as not 
requiring emissions that occur during periods of malfunction to be 
factored into development of CAA section 129 standards. This reading 
has been upheld as reasonable by the D.C. Circuit in U.S. Sugar Corp. 
v. EPA, 830 F.3d 579, 606-610 (2016). The Court's reasoning in U.S. 
Sugar applies equally to section 129 standards given the similarities 
between the section 112 and 129 standard setting criteria. For the 
reason stated earlier in this preamble, we are proposing revisions to 
40 CFR 60.58b and 40 CFR 60.59b.
4. Proposed Changes for Optional Continuous Monitoring
    The 2006 final amendments to the large MWC rules revised the PM and 
Hg compliance testing requirements to allow the optional use of a PM 
CEMS or Hg CEMS in place of stack testing, and would allow the optional 
use of multi-metal, HCl, PCDD/PCDF CEMS in place of stack tests after 
performance specifications for these CEMS are promulgated (see 71 FR 
27326, May 10, 2006). These amendments also allowed for continuous 
automated sorbent monitoring for Hg and PCDD/PCDF. Since this time, 
other performance specifications have been promulgated and the EPA is 
proposing to incorporate them into these large MWC requirements. 
However, another consideration is to reinvestigate whether the use of 
CEMS for compliance testing requires the EPA to adopt alternative 
emission limits. In the 2006 final rule, we made the following 
statements (see 71 FR 27330, May 10, 2006):

    The move from once per year stack testing (where emission limits 
were calculated from the 99 percentile) to CEMS (99.7 percentile) 
suggests the emission limit should be increased if the same data 
averaging period is used. To address this, the final rule increases 
the data averaging period from 8 hours (typical particulate matter 
and mercury stack test period) to a 24-hr daily average if 
particulate matter or mercury CEMS are used. Past analysis of sulfur 
dioxide CEMS and nitrogen oxides CEMS data (and utility particulate 
matter CEMS data) indicate increasing the averaging period to a 24-
hr daily average will reduce emissions variability and associated 
peak emissions estimates. EPA supports the optional use of 
particulate matter and mercury CEMS but is fully aware that no 
particulate matter CEMS or mercury CEMS data from MWC units are 
available from domestic MWC units. EPA encourages MWC owners or 
operators who elect to apply particulate matter or mercury CEMS, to 
notify EPA as soon as data are collected to allow a determination if 
alternative emission limits are appropriate.

    Note that, if owners and operators decide to use PM or Hg CEMS for 
compliance demonstration purposes, these data must be submitted to EPA.
    As noted in this section, more recent combustion rulemakings have 
been promulgated with 30-day hourly rolling averages for pollutants 
measured with Hg CEMS (e.g., Mercury Air Toxics Standards--40 CFR part 
63, subpart UUUU) or other optional CEMS (e.g., CISWI NSPS and EG, 40 
CFR part 60, subparts CCCC and DDDD). We request comment on whether the 
30-day rolling hourly average is appropriate to use in the large MWC 
source category, both for the currently required CEMS and for optional 
CEMS and continuous automated sampling systems, considering potential 
CEMS reliability/availability concerns, especially for the optional 
CEMS devices that have not been extensively applied commercially and 
lack the extensive track record of the more established CEMS. We also 
request comment on whether data are available to analyze whether an 
alternative emission limit should be established for pollutants that 
have standards based on stack test data.
5. Changes To Streamline Regulatory Text Within the Large MWC EG and 
NSPS
    The EPA is proposing changes to the regulatory format of the large 
MWC standards to be more accessible and easier to follow than the 1995 
large MWC rule. Paragraph text describing emission standards and 
performance testing requirements would be converted to tables to 
facilitate easier implementation and understanding of the requirements, 
especially as staged compliance dates are introduced with the proposed 
standards. These streamlining efforts do not change the regulatory 
numbering of the 1995 rule but do add new tables to the end of the 
subparts for these requirements, similar to other more recently 
developed CAA section 129 standards. A memorandum showing the rule 
edits that would be necessary to incorporate the changes to 40 CFR part 
60, subparts Cb and Eb proposed in this action is available in the 
docket (Docket ID No. EPA-HQ-OAR-2017-0183).
6. Closing the 2007 Proposed Reconsideration of the Large MWC EG and 
NSPS
    In this proposal, we are completing action on the March 20, 2007, 
notice of reconsideration that was never finalized. In that notice, we 
announced our reconsideration of three out of four aspects of the rule 
that were requested for reconsideration: operator stand-in provisions, 
data requirements for continuous monitors, and the status of operating 
parameters during the two weeks prior to Hg and PCDD/PCDF testing (see 
72 FR 13016). As a brief summary:
     Operator Stand-In Provisions--A petitioner was concerned 
that the EPA was, in its operator stand-in provisions, ``allow(ing) 
untrained employees to perform the duties of a certified chief facility 
operator or certified shift operator.'' The EPA discussed the various 
certification and training requirements of the standards and concluded 
that the ``. . . limited exemption did not undermine the MWC 
regulation, did not allow untrained individuals to operate the MWC, and 
would, in fact, improve the efficiency of the regulation by reducing 
unnecessary reporting and paperwork requirements'' (see 72 FR 13019).
     Data Requirements for Continuous Monitors--Petitioners 
were concerned about the EPA's elimination of a

[[Page 4258]]

``requirement that operators obtain CEMS data for 75 percent of the 
operating hours per day before the data is counted toward the CEMS data 
availability requirements.'' The Agency discussed how the CEMS data 
availability requirements have continually increased as CEMS have 
become more reliable and noted that most rules have migrated away from 
a daily basis and instead use a percent of operation basis. As a 
result, the requirements (without the daily component) are superior. We 
also note that we are proposing updated CEMS data availability 
requirements in this action which require even greater CEMS data 
availability than the requirements that were requested for 
reconsideration by petitioners (see 72 FR 13019).
     Status of Operating Parameters During the Two Weeks Prior 
to Hg and PCDD/PCDF Testing--A petitioner claimed that the EPA ``now 
allows MWC to avoid meeting mass carbon feed rate limits for PCDD/PCDF 
testing, as well as Hg testing, and increases to more than four weeks 
per year the total amount of time that MWC can avoid meeting mass 
carbon feed rate limits.'' The EPA discussed the need for optimization 
testing and demonstrated how, out of economic and practical concerns, 
these are done in short, often the same, test periods so that concerns 
over four weeks of carbon feed rate parameters being waived are not 
warranted. As a result, the EPA stated that the provision for 
optimization testing for ACI is appropriate and the EPA is not 
proposing to change it (see 72 FR 13019).
    Of the three issues that we granted reconsideration on and 
discussed in the 2007 proposal notice, only a single comment expressing 
support for our proposed reconsideration approach was received. 
Therefore, in absence of adverse comment, we are proposing to finalize 
our reconsideration as previously proposed.\24\ EPA seeks comment on 
the issues discussed above.
---------------------------------------------------------------------------

    \24\ While not necessary to respond, we note that the Pb 
standard aspect of the petition for reconsideration that was not 
granted is considered moot based on this proposed action to address 
the voluntary remand of the MACT floors which would result in more 
stringent Pb standards.
---------------------------------------------------------------------------

7. Updating Operator Training Exam Requirements
    In this proposal, we are updating the citation to and incorporating 
by reference the American Society of Mechanical Engineers (ASME) 
Standard for the Qualification and Certification of Resource Recovery 
Facility Operators (QRO). In the 1995 large MWC rule, the cited QRO was 
the 1994 version, QRO-1-1994. Since that time, ASME has released a 2005 
version as the most recent one available. This QRO is identified as 
QRO-1-2005 and will be incorporated by reference and updated within the 
text of 40 CFR 60.17(g) and 60.54b.
8. Proposed Revisions to Title V Permitting Requirements for Air 
Curtain Incinerators Burning Only Wood Waste, Clean Lumber, and Yard 
Waste
    CAA section 129(e) generally requires title V permits \25\ for 
``solid waste incineration units.'' Under CAA section 129(g)(1), 
however, the term ``solid waste incineration unit'' does not include 
air curtain incinerators that only burn wood wastes, yard wastes, and 
clean lumber (and that comply with opacity limitations). In our view, 
the opacity limitations applicable under CAA 129 to such air curtain 
incinerators are not standards or regulations ``under section 7411,'' 
such that the air curtain incinerators would be subject to a title V 
permitting requirement under CAA section 502(a). The 1995 large MWC 
rule (see 60 FR 65387, December 19, 1995) contains a regulatory 
requirement that air curtain incinerators that burn only wood waste, 
clean lumber, and yard waste must apply for and obtain a tile V 
operating permit. The EPA is proposing to eliminate this regulatory 
title V permitting requirement for such air curtain incinerators that 
are not located at a major source or subject to title V for other 
reasons.
---------------------------------------------------------------------------

    \25\ Title V permits are required by Title V of the Clean Air 
Act and are legally enforceable documents designed to improve 
compliance by clarifying what sources must do to control pollution 
due to federal or state regulations. More information is available 
at: https://www.epa.gov/title-v-operating-permits/basic-information-about-operating-permits.
---------------------------------------------------------------------------

    As background, in previous rulemaking for the Other Solid Waste 
Incinerators EG and NSPS (40 CFR part 60 subparts EEEE and FFFF), we 
provided for title V permitting for these air curtain incinerators for 
various reasons, as explained in 70 FR 74884-74885 (December 16, 2005). 
In particular, we believed initially that compliance with a title V 
permit was necessary to assure compliance with the opacity requirements 
established for such incinerators. Since then, the EPA has received 
feedback from several states indicating that the title V requirements 
are unnecessarily burdensome and expensive for states to maintain for 
these air curtain incinerators. Based on available data, air curtain 
incinerators that burn exclusively wood waste, clean lumber, and yard 
waste are commonly located at facilities that would not otherwise 
require a title V operating permit (such as land clearing operations in 
public or private land) and, to EPA's knowledge, no large MWC facility 
also operates an air curtain incinerator on premises.\26\ In this 
rulemaking, we are reconsidering the need for a regulatory requirement 
for title V permitting for these air curtain incineration units that 
are only subject to an opacity limitation and related requirements to 
assure compliance, because such units are not considered solid waste 
incineration units under CAA section 129. Also, based on input from 
various states on the burdens and costs of title V permitting for such 
incinerators, we no longer believe it is appropriate or necessary to 
require title V permitting. We request comment on the proposed removal 
of title V permitting requirements for air curtain incinerators that 
burn only wood waste, clean lumber, and yard waste under CAA section 
129.
---------------------------------------------------------------------------

    \26\ CAA section 129(e) generally requires title V permits for 
``solid waste incineration units.'' Under CAA section 129(g)(1), 
however, the term ``solid waste incineration unit'' does not include 
air curtain incinerators that only burn wood wastes, yard wastes, 
and clean lumber (and that comply with opacity limitations). In 
addition, in our view, the opacity limitations applicable, under CAA 
section 129, to such air curtain incinerators are not standards or 
regulations ``under section 7411,'' such that the air curtain 
incinerators would be subject to a title V permitting requirement 
under CAA section 502(a).
---------------------------------------------------------------------------

9. Electronic Reporting
    The EPA is proposing that owners and operators of large MWC units 
submit electronic copies of required performance test reports, 
performance evaluation reports, semiannual compliance reports, annual 
reports, and certain notifications through the EPA's Central Data 
Exchange (CDX) using the Compliance and Emissions Data Reporting 
Interface (CEDRI). A description of the electronic data submission 
process is provided in the memorandum Electronic Reporting Requirements 
for New Source Performance Standards (NSPS) and National Emission 
Standards for Hazardous Air Pollutants (NESHAP) Rules, available in the 
docket for this action. The proposed rule requires that performance 
test results collected using test methods that are supported by the 
EPA's Electronic Reporting Tool (ERT) as listed on the ERT website \27\ 
at the time of the test be submitted in the format generated through 
the use of the ERT or an electronic file consistent with the xml schema 
on the ERT website, and other performance test results be submitted in 
portable document format

[[Page 4259]]

(PDF) using the attachment module of the ERT. Similarly, performance 
evaluation results of continuous emissions monitoring systems (CEMS) 
measuring relative accuracy test audit (RATA) pollutants that are 
supported by the ERT at the time of the test must be submitted in the 
format generated through the use of the ERT or an electronic file 
consistent with the xml schema on the ERT website, and other 
performance evaluation results be submitted in PDF using the attachment 
module of the ERT. The proposed rule requires that certain 
notifications are submitted as a PDF upload in CEDRI.
---------------------------------------------------------------------------

    \27\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For semiannual and annual reports, the proposed rule requires that 
owners and operators use the appropriate spreadsheet template to submit 
information to CEDRI. A draft version of the proposed template for 
these reports is included in the docket for this action.\28\ The EPA 
specifically requests comment on the content, layout, and overall 
design of the template(s).
---------------------------------------------------------------------------

    \28\ See 60.59b and 60.39b Annual and Semiannual Compliance 
Report Proposal Draft, available at Docket ID. No. EPA-HQ-OAR-2017-
0183.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. These 
circumstances are (1) outages of the EPA's CDX or CEDRI which preclude 
an owner or operator from accessing the system and submitting required 
reports and (2) force majeure events, which are defined as events that 
will be or have been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevent an owner or operator from complying with 
the requirement to submit a report electronically. Examples of force 
majeure events are acts of nature, acts of war or terrorism, or 
equipment failure or safety hazards beyond the control of the facility. 
The EPA is providing these potential extensions to protect owners and 
operators from noncompliance in cases where they cannot successfully 
submit a report by the reporting deadline for reasons outside of their 
control. In both circumstances, the decision to accept the request for 
additional time to report is within the discretion of the 
Administrator, and reporting should occur as soon as possible.
    The electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends in data availability and 
transparency, will further assist in the protection of public health 
and the environment, will improve compliance by facilitating the 
ability of regulated facilities to demonstrate compliance with 
requirements and by facilitating the ability of delegated state, local, 
tribal, and territorial air agencies and the EPA to assess and 
determine compliance, and will ultimately reduce burden on regulated 
facilities, delegated air agencies, and the EPA. Electronic reporting 
also eliminates paper-based, manual processes, thereby saving time and 
resources, simplifying data entry, eliminating redundancies, minimizing 
data reporting errors, and providing data quickly and accurately to the 
affected facilities, air agencies, the EPA, and the public. Moreover, 
electronic reporting is consistent with the EPA's plan \29\ to 
implement Executive Order 13563 and is in keeping with the EPA's 
Agency-wide policy \30\ developed in response to the White House's 
Digital Government Strategy.\31\ For more information on the benefits 
of electronic reporting, see the memorandum Electronic Reporting 
Requirements for New Source Performance Standards (NSPS) and National 
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, 
referenced earlier in this section.
---------------------------------------------------------------------------

    \29\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \30\ E-Reporting Policy Statement for EPA Regulations, September 
2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \31\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

10. Technical and Implementation Corrections
    The EPA is proposing corrections and clarifications to the NSPS and 
EG that were identified during implementation of the previous 
regulations. These amendments are being made to improve the clarity of 
the NSPS and EG, and to make technical corrections that have been 
brought to the EPA's attention since the December 19, 1995, 
promulgation. These corrections and clarifications will improve the 
implementation of the regulations by large MWC owners and operators, 
and state and Federal air pollution control agencies.
    Following is a list of the most significant revisions. Non-
substantive typographical corrections are also proposed but are not 
listed here.
Applicability and Delegation of Authority
     Adding 40 CFR 60.32b(o) and 60.50b(q) to clarify that 
large MWC units subject to 40 CFR part 60, subpart Cb are not subject 
to 40 CFR part 60, subpart Db. This makes the NSPS and EG consistent 
with 40 CFR part 60, subpart Db, which exempts large MWC units from 
that subpart.
     Revising 40 CFR 60.30b(b) to clarify that approval of 
certain exemption claims in 40 CFR 60.32b(b)(1), (d), (e), (f)(1), and 
(i)(1); approval of a NOX trading program; approval of major 
alternatives to test methods and monitoring; approval of waivers of 
recordkeeping; and performance test and data reduction waivers are 
retained by the EPA Administrator and not transferred to the state upon 
delegation of authority to the state to implement an approved state 
plan.
     Revising 40 CFR 60.50b(n)(2) to clarify that the EPA 
Administrator retains sole authority to issue the federally enforceable 
11 tpd limit for exemptions in 40 CFR 60.50b(b) and the 30 percent 
municipal waste limit for co-fired units in 40 CFR 60.50b(j)(2).
     Revising 40 CFR 60.50b(n)(4) to correct a typographical 
error and clarify that the EPA Administrator retains sole authority to 
review and approve demonstrations that establish the relationship 
between carbon dioxide (not CO) and oxygen as part of initial and 
annual performance tests.
Definitions
     Amending the definition of ``federally enforceable'' in 40 
CFR 60.51b to correct a cross referencing error and reference 40 CFR 
51.165 and 51.166 instead of 40 CFR 51.18 and 51.24.
Performance Testing and Monitoring
     Revising 40 CFR 60.58b(f)(7) and 60.58b(k)(4) to correct 
an oversight and clarify that the revised testing schedule (once per 
calendar year, but no less than 9 months and no more than 15 months 
following the previous test) also applies to fugitive ash and HCl 
testing.
Reporting and Recordkeeping Requirements
     Revising 40 CFR 60.39b(b) and (g) to clarify that state 
plans were due on May 10, 2007, not April 28, 2007.
     Adding 40 CFR 60.59b(d)(2)(iii) to clarify that all data 
for continuous monitoring systems must be recorded using ``local time'' 
for the location where the affected facility is located unless an 
alternative time system is approved by the Administrator.

[[Page 4260]]

     Revising 40 CFR 60.59b(g)(1) to require that owners and 
operators must additionally report the annual arithmetic average of all 
hourly values recorded during operations for the reporting year.

C. What compliance dates are we proposing, and what is the rationale 
for the proposed compliance dates?

    Under the proposed amendments to the EG and consistent with CAA 
section 129, revised state plans containing the revised existing source 
emission limits and other requirements in the proposed amendments would 
be due within 1 year after promulgation of the amendments. That is, 
states would have to submit revised plans to the EPA 1 year after the 
date on which the EPA promulgates revised standards.
    The proposed amendments to the EG would then allow existing large 
MWC units to demonstrate compliance with the amended standards as 
expeditiously as practicable after approval of a state plan, but no 
later than three years from the date of approval of a state plan or 
five years after promulgation of the revised standards, whichever is 
earlier. Consistent with CAA section 129, the EPA expects states to 
require compliance as expeditiously as practicable. However, because we 
anticipate that many large MWC units will find it necessary to retrofit 
existing emission control equipment and/or install additional emission 
control equipment to meet the proposed revised limits, the EPA 
anticipates that states may choose to provide the 3-year compliance 
period allowed by CAA section 129(f)(2).\32\
---------------------------------------------------------------------------

    \32\ The CAA Section 129 does not require EPA to establish the 
control technology sources must use to meet a numeric emission 
limit. The costs are based on assumptions of air pollution control 
device retrofits, new equipment, or increased use of sorbent that 
may be needed to comply with the emission limits, but owners will 
evaluate and use the controls that they determine are necessary for 
their source.
---------------------------------------------------------------------------

    In revising the standards in a state plan, a state would have two 
options. First, it could include both the 2006 large MWC standards and 
the new standards in its revised state plan, which would allow a phased 
approach in applying the new limits. That is, the state plan would make 
it clear that the standards in the 2006 large MWC rule remain in force 
for large MWC units and apply until the date the revised existing 
source standards are effective (as defined in the state plan).\33\ 
Second, states whose existing large MWC units do not need to improve 
their performance to meet the revised standards may consider an 
alternative approach where the state would replace the 2006 large MWC 
rule standards with the standards in the final rule, follow the 
procedures in 40 CFR part 60, subpart B, and submit a revised state 
plan to the EPA for approval. If the revised state plan contains only 
the revised standards (i.e., the 2006 large MWC rule standards are not 
retained), then the revised standards must become effective immediately 
for those units that are subject to the 2006 large MWC rule, since the 
2006 large MWC rule standards would be removed from the state plan. We 
request comment on the feasibility of the proposed compliance dates and 
rationales.
---------------------------------------------------------------------------

    \33\ All sources currently subject to the 1995 large MWC EG or 
NSPS will become existing sources once the final revised large MWC 
standards are in place. See section III.B above.
---------------------------------------------------------------------------

    The EPA will revise the existing Federal plan to incorporate any 
changes to existing source emission limits and other requirements that 
the EPA ultimately promulgates. The Federal plan applies to large MWC 
units in any state without an approved state plan. The proposed 
amendments to the EG would allow existing large MWC units subject to 
the Federal plan up to five years after promulgation of the revised 
standards to demonstrate compliance with the amended standards, as 
required by CAA section 129(b)(3).

IV. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    The large MWC source category comprises units with a capacity 
greater than 250 tpd of MSW. The current population of large MWC units 
is estimated to include 152 units at 57 facilities nationwide. Of 
these, 129 (85 percent) are mass burn units, and the remaining are 
refuse-derived fuel systems. Approximately 30 percent of currently 
operating large MWCs are subject to 40 CFR part 60, subpart Eb (2006 
NSPS limits), with the remaining subject to 40 CFR part 60, subparts Ea 
(NSPS limits for units constructed after December 20, 1989, and on or 
before September 20, 1994) or Cb (EG for units constructed before 
September 20, 1994). We estimate that there are 22 municipally owned or 
operated facilities with a total of 62 municipally owned or operated 
large MWC units.

B. What are the air quality impacts?

    We have estimated the potential emissions reductions from existing 
sources that may be realized through implementation of the emission 
limits under consideration. Emissions reductions were estimated for all 
units where add-on controls, improvements to existing control devices, 
or increased carbon or lime injection rates would likely be required to 
meet a given limit.\34\ Because good combustion practices are assumed 
to be the most effective control for CO, as opposed to add-on controls 
or control improvements, no additional control costs or associated 
emission reduction benefits were assessed for CO.\35\ For all other 
pollutants, it was assumed that units would comply with emission limits 
by operating the control measure(s) described in the large MWC cost 
memorandum.\36\ Reductions in PM less than 2.5 microns 
(PM2.5) were also assessed. These reductions are presented 
in Table 7 of this preamble.
---------------------------------------------------------------------------

    \34\ See memorandum ``Emission Reduction Estimates for Existing 
Large MWCs'' available at Docket ID. No. EPA-HQ-OAR-2017-0183.
    \35\ Furthermore, the annual maximum data for the majority of 
sources do not reflect actual performance. As noted in section 
III.B.3., we are proposing significant changes to the continuous 
monitoring reporting provisions so that we have access to continuous 
data. Therefore, an assessment of any presumed emission reductions 
in comparison to the reevaluated MACT floor for CO is not possible 
at this time.
    \36\ See memorandum ``Compliance Cost Analyses for Proposed 
Large MWC Rule Amendments'' available at Docket ID. No. EPA-HQ-OAR-
2017-0183.

                         Table 7--Estimated Emissions Reductions by Regulatory Scenario
----------------------------------------------------------------------------------------------------------------
                                                                                                    Reductions
                                                               Reductions    Reductions achieved     achieved
             Pollutant                   Unit of measure        achieved     through  beyond-the-     through
                                                              through MACT      floor/ 5-year        proposed
                                                             floor scenario    review scenario       scenario
----------------------------------------------------------------------------------------------------------------
Cd.................................  ton/yr................          0.0443               0.0572          0.0443
Pb.................................  ton/yr................           0.181                0.812           0.181
PM.................................  ton/yr................            24.4                 87.7            24.4

[[Page 4261]]

 
PM2.5..............................  ton/yr................            14.2                 47.1            14.2
Hg.................................  lb/yr.................            57.0                  333            57.0
PCDD/PCDF..........................  g/yr..................            52.2                  249            52.2
HCl................................  ton/yr................             344                  928             344
SO2................................  ton/yr................           2,420                4,350           2,420
NOX................................  ton/yr................           2,230               11,400          11,400
                                    ----------------------------------------------------------------------------
    Total..........................  ton/yr................           5,020               16,800          14,200
----------------------------------------------------------------------------------------------------------------

    Indirect or secondary air emissions can result from the increased 
energy requirements associated with the operation of new control 
devices (i.e., increased emissions of criteria pollutants from the 
power plants supplying that additional electricity). However, the 
reevaluated emission limits for large MWCs are unlikely to have any 
consequential secondary air impacts, because the increase in energy 
requirements due to new control measures is minimal, and what little 
additional energy is required would be redirected from power already 
being generated at the plant.
    We expect that existing units still operating electrostatic 
precipitators for particulate control will retrofit with a fabric 
filter control device, but the difference in energy needs for each of 
these devices is expected to be minimal. Furthermore, any improvements 
made to existing fabric filters will not be significant enough to 
require a larger fan, meaning that electricity consumption would remain 
unchanged. For NOX control, most units already have SNCR, so 
further control would require retrofitting with ASNCR or 
LNTM NOX technology. Existing SNCR equipment 
would likely be used by these retrofit options, meaning any additional 
power consumption requirements would be minimal. In the rare case where 
a unit goes from no SNCR to SNCR, the minimal amount of power required 
to pump reagent to the furnace would be supplied by the unit's own 
generating capabilities, rather than through fossil fuel combustion. We 
expect Hg and PCDD/PCDF to be further controlled through increased 
carbon injection for units that already have ACI systems, or with the 
installation of new ACI systems. Increases in power demand for existing 
systems and demand for new systems are both expected to be minimal and 
would be met with a small fraction of the power generation from the 
facility. Similarly, power demand increases for acid gas control 
systems are expected to be minimal and met with power that facilities 
are already generating. Acid gases are typically controlled with a dry 
sorbent injector scrubber or spray dryer absorber. Additional control 
(i.e., increased sorbent injection rates in the existing control 
device) would require only minimal increases in sorbent conveying 
equipment power needs. If an owner or operator determined a need for a 
retrofit to a CFBS to meet the standards for acid gases, this retrofit 
could provide a small savings in sorbent injection and power 
consumption needs. A CFBS is generally more effective at acid gas 
control for the same amount of sorbent and at an equal to lesser power 
consumption than spray dryer absorbers.

C. What are the water, solid waste, and energy impacts?

    We anticipate affected sources will need to apply additional 
controls to meet the proposed emission limits. These control measures 
impact waste disposal, water usage, and electricity requirements.
    PM controls or control improvements will increase the amount of 
particulate collected that will require disposal. Increased ACI rates 
for Hg and PCDD/PCDF control, as well as increased lime injection for 
acid gas control, will also require additional waste disposal. The 
total amount of solid waste that would require disposal as a result of 
control measures implemented to meet the proposed limits is anticipated 
to be approximately 66,800 tpy. This includes 16.7 tpy from PM capture, 
15,000 tpy from carbon injection, and 51,800 tpy from lime injection.
    Advanced SNCR for NOX control is the only control 
measure among those expected to be implemented which will require 
additional water usage, as water is used in the reagent solution 
injected into the furnace and/or flue gas duct. We estimate that 
42,800,000 gallons of water per year will be used for new 
NOX control. The injected liquid evaporates in the flue gas 
stream, so there would be no associated wastewater disposal 
requirements.
    The energy impacts associated with meeting the proposed emission 
limits would consist primarily of additional electricity needs to run 
added or improved controls. However, large MWCs are already generating 
their own electricity, and the power demand for added or improved 
controls would be met at the cost of electricity sales to customers. 
The installation of fabric filters would require some unit downtime, 
which would result in a decrease in a facility's electricity 
production. We estimate an electricity loss of approximately 35,300 
megawatt-hours for PM control.
    Although we anticipate minimal growth in this source category, we 
recognize the possibility that some new units may be installed in the 
future. However, we expect any new units to be similar to the most 
recently constructed large MWC, which can already meet the limits 
considered for each option. Therefore, no additional controls or 
associated secondary impacts are anticipated for new sources as a 
result of the proposed limits.
    Further details regarding water, solid waste, and energy impacts 
for new and existing sources are provided in the large MWC secondary 
impacts memorandum.\37\
---------------------------------------------------------------------------

    \37\ ``Secondary Impacts of Control Scenarios for Large MWC 
Standards'' available at Docket ID. No. EPA-HQ-OAR-2017-0183.
---------------------------------------------------------------------------

D. What are the cost impacts?

    We have estimated compliance costs for all existing units to add 
the necessary controls to meet the proposed standards.\38\ We 
anticipate an overall capital investment of approximately $309 million, 
with an associated total

[[Page 4262]]

annualized cost (including operating and maintenance costs) of 
approximately $99.8 million (in 2022 dollars). The cost breakdown by 
pollutant grouping and regulatory option are provided in Table 8 of 
this preamble.
---------------------------------------------------------------------------

    \38\ See memorandum ``Compliance Cost Analyses for Proposed 
Large MWC Rule Amendments'' available at Docket ID. No. EPA-HQ-OAR-
2017-0183.

                                                     Table 8--Compliance Costs by Regulatory Option
                                                                       [2025-2044]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      MACT floor limit option         Beyond-the-floor/5-year review             Proposed option
                                                ----------------------------------                option               ---------------------------------
               Pollutant grouping                                   Total annual  -------------------------------------                    Total annual
                                                  Total capital     cost  ($/yr)     Total capital      Total annual     Total capital     cost  ($/yr)
                                                    cost  ($)           \a\            cost  ($)      cost  ($/yr) \a\     cost  ($)           \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Particulates (Cd, Pb, PM)......................      $35,700,000       $5,460,000       $113,000,000       $16,400,000      $35,700,000       $5,460,000
Hg and PCDD/PCDF...............................       16,400,000       22,000,000         65,000,000       121,000,000       16,400,000       22,000,000
Acid gases (HCl and SO2).......................  ...............       12,900,000      1,120,000,000       386,000,000  ...............       12,900,000
NOX............................................       50,800,000       10,800,000        257,000,000        59,400,000      257,000,000       59,400,000
                                                --------------------------------------------------------------------------------------------------------
    Total control costs........................      103,000,000       51,100,000      1,560,000,000       582,000,000      309,000,000       99,800,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Includes operating and maintenance costs. Capital annualized over 20 years at an interest rate of 7.5% unless noted otherwise (See ``Compliance Cost
  Analyses of the Proposed Rule Amendments for Large MWC Rule Amendments'' memorandum in the docket to this rulemaking for more details).

E. What are the economic impacts?

    The EPA conducted an economic impact analysis for the proposed rule 
in the Regulatory Impact Analysis (RIA), which is available in the 
docket for this action. If the compliance costs, which are key inputs 
to an economic impact analysis, are small relative to the receipts of 
the affected companies, then the impact analysis may consist of a 
calculation of annual (or annualized) costs as a percent of sales for 
affected parent companies. This type of analysis is often applied when 
a partial equilibrium or more complex economic impact analysis approach 
is deemed unnecessary given the expected size of the impacts. The 
annualized cost per sales for a company represents the maximum price 
increase in the affected product or service needed for the company to 
completely recover the annualized costs imposed by the regulation, 
assuming no change in affected output. We conducted a cost-to-sales 
analysis to estimate the economic impacts of this proposal, given that 
the equivalent annualized value (EAV) of the compliance costs over the 
period of 2025 to 2044 are $120 million using a 7 percent or $110 
million using a 3 percent discount rate in 2022 dollars, which is small 
relative to the revenues of the affected industry.
    The EPA estimated the annualized compliance cost each firm is 
expected to incur and determined the estimated cost-to-sales ratio for 
affected units. This cost averages 0.15 percent of parent company 
revenue and does not exceed 3.5 percent of parent company revenue for 
any affected unit. The estimated cost-to-sales ratio for affected 
entities, none of which are small according to Small Business 
Administration size standards, averages 1.1 percent and does not exceed 
4.4 percent.\39\ Therefore, the projected economic impacts of the 
expected compliance costs of the proposal are likely to be relatively 
small as compared to parent company revenue.
---------------------------------------------------------------------------

    \39\ The proposal is expected to generate annual compliance cost 
increases greater than 2 percent of annual revenue for five out of 
21 ultimate parent entities. Of these, three are municipally owned, 
one was previously owned by a collection of municipalities, and one 
is privately owned with 56 units under one parent company. The 
average cost-to-sales ratio of the remaining 16 entities is 
approximately 0.35 percent.
---------------------------------------------------------------------------

F. What are the benefits?

    Pursuant to E.O. 12866 as amended by E.O. 14094, the RIA for this 
action analyzes the benefits associated with the projected emissions 
reductions under this proposal to inform the EPA and the public about 
these projected impacts.
    This proposed rule is projected to reduce emissions of Hg and non-
Hg metal hazardous air pollutant (HAP), PM2.5, 
SO2, and NOX nationwide. The potential impacts of 
these emissions reductions are discussed in detail in Section 4 of the 
RIA.
    The projected reductions in Hg are expected to reduce the 
bioconcentration of methylmercury in fish. Subsistence fishing is 
associated with vulnerable populations, including minorities and those 
of low socioeconomic status.
    The potential benefits from reducing Hg and non-Hg metal HAP were 
not monetized and are therefore not reflected in the benefit-cost 
estimates associated with this proposal due to methodology and data 
limitations. Instead, we provide a qualitative discussion of the health 
effects associated with HAP emitted from sources subject to control 
under the proposed action. The EPA remains committed to supporting 
research to address these limitations. Potential benefits from 
reductions of PCDD/PCDF and reduction in nitrogen and sulfur deposition 
were also not monetized in this analysis and are therefore not directly 
reflected in the quantified benefit-cost comparisons. We anticipate 
that taking these non-monetized effects into account would show the 
proposal to have a greater net benefit.
    The proposed control measures to reduce HAP and PM2.5 
emissions could improve air quality and the health of persons living in 
surrounding communities. The proposed control measures are expected to 
reduce about 0.23 tpy of HAP metal emissions, including emissions of 
Cd, Pb, Hg, and PCDD/PCDF. We provide a qualitative discussion of the 
health effects associated with HAP emitted from sources subject to 
control under the proposed action in Section 4.2 of the RIA, available 
in the docket for this action. The EPA remains committed to improving 
methods for estimating HAP benefits by continuing to explore additional 
aspects of HAP-related risk from large MWCs, including the distribution 
of that risk.
    The proposed control measures are also estimated to reduce 
PM2.5 emissions by about 14 tpy for the source category. The 
EPA estimated monetized benefits related to avoided premature mortality 
and morbidity associated with reduced exposure to PM2.5 for 
2025 to 2044. The present value (PV) of the short-term benefits for the 
proposed rule range from $5.1 billion at a 3 percent discount rate to 
$3.3 billion at a 7 percent discount rate with an EAV of $340 million 
and $310 million, respectively. The EAV represents a flow of constant 
annual values that would

[[Page 4263]]

yield a sum equivalent to the PV. The PV of the long-term benefits for 
the proposed rule range from $17 billion at a 3 percent discount rate 
to $10 billion at a 7 percent discount rate with an EAV of $1.1 billion 
and $960 million, respectively. All estimates are reported in 2022 
dollars. For the full set of underlying calculations see the LMWC 
Workbook, available in the docket for this action.

G. What environmental justice analysis did we conduct?

    The locations of the new, modified, and reconstructed sources that 
will become subject to the proposed large MWC NSPS (40 CFR part 60, 
subpart Eb) are not known. Therefore, to examine the potential for any 
EJ issues that might be associated with the proposed NSPS, we performed 
a proximity demographic analysis for all 57 existing large MWC 
facilities that are currently subject to 40 CFR part 60, subparts Cb, 
Ea and Eb. These characterize populations near existing facilities that 
might modify or reconstruct in the future and become subject to the 
proposed NSPS requirements. This proximity demographic analysis 
characterized the individual demographic groups of the populations 
living within 5 kilometers (approximately 3.1 miles) and within 50 
kilometers (approximately 31 miles) of the existing facilities. The EPA 
then compared the data from this analysis to the national average for 
each of the demographic groups.
    The results of the proximity demographic analysis are shown in 
Table 9 of this preamble. The percent of the population living within 5 
kilometers of the existing large MWC facilities in the following 
racial/ethnicity demographics are above the national average: African 
American (20 percent versus 12 percent nationally), Hispanic/Latino (23 
percent versus 19 percent nationally), and other/multiracial (9 percent 
versus 8 percent nationally). In addition, the percent of population 
living within 5 kilometers of the existing large MWC facilities is 
above the national average for the following demographics: people 
living below the poverty level (16 percent versus 13 percent 
nationally), people over 25 without a high school diploma (15 percent 
versus 12 percent nationally), and those experiencing linguistic 
isolation (8 percent versus 5 percent nationally).
    The percent of the population living within 50 kilometers of the 
existing large MWC facilities in the following racial/ethnicity 
demographics are above the national average: African American (14 
percent versus 12 percent nationally), Hispanic/Latino (21 percent 
versus 19 percent nationally), and other/multiracial (11 percent versus 
8 percent nationally). In addition, the percent of population living 
within 50 kilometers of the large MWC existing facilities is above the 
national average for linguistic isolation (8 percent versus 5 percent 
nationally).

                   Table 9--Proximity Demographic Assessment Results for Large MWC Facilities
----------------------------------------------------------------------------------------------------------------
                                                                                    Population
                                                                                   within 50 km     Population
                        Demographic group                           Nationwide         of 57      within 5 km of
                                                                                    facilities     57 facilities
----------------------------------------------------------------------------------------------------------------
Total population................................................     328,016,242      82,056,095       3,916,651
----------------------------------------------------------------------------------------------------------------
                                          Race and Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              60              54              48
African American................................................              12              14              20
Native American.................................................             0.7             0.3             0.4
Hispanic or Latino (includes white and nonwhite)................              19              21              23
Other and multiracial...........................................               8              11               9
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below poverty level.............................................              13              12              16
Above poverty level.............................................              87              88              84
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without a high school diploma.......................              12              12              15
Over 25 and with a high school diploma..........................              88              88              85
----------------------------------------------------------------------------------------------------------------
                                       Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically isolated.........................................               5  ..............  ..............
----------------------------------------------------------------------------------------------------------------
Notes:
 The nationwide population count and all demographic percentages are based on the Census' 2015-2019
  American Community Survey 5-year block group averages and include Puerto Rico. Demographic percentages based
  on different averages may differ. The total population counts within 5 km and 50 km of all facilities are
  based on the 2010 Decennial Census block populations.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category for these analyses. A person is identified as one of five racial/ethnic categories above: White,
  African American, Native American, Other and Multiracial, or Hispanic/Latino. A person who identifies as
  Hispanic or Latino is counted as Hispanic/Latino for this analysis, regardless of what race this person may
  have also identified as in the Census.

    The proposed large MWC NSPS and EG (40 CFR part 60, subparts Cb and 
Eb) cover new and existing solid waste incineration units ``with 
capacity greater than 250 tons per day combusting municipal waste.'' 
The proposed standards would increase stringency of existing regulation 
of emissions of the nine pollutants listed in CAA section 129: Cd, Hg, 
Pb, PM, HCl, SO2, PCDD/PCDF, CO, and NOX, among 
other proposed actions (see section I.A of this preamble for a summary 
of the major requirements being proposed). As discussed in section 
IV.B, the proposed amendments to the large MWC NSPS and EG would result 
in an estimated

[[Page 4264]]

14,200 tons per year reduction in regulated pollutants.
    The methodology and the results (including facility-specific 
results) of the demographic analysis are presented in the document 
titled Analysis of Demographic Factors for Populations Living Near 
Large Municipal Waste Combustors, which is available in the docket for 
this action.

V. Request for Comments

    We solicit comments on this proposed action. In addition to general 
comments on this proposed action, we are also interested in additional 
data that may improve the analyses, including data on the number of 
facilities that will require retrofit and data to inform EPA's 
projections of APCD use by large MWCs. We are specifically interested 
in receiving any information regarding developments in practices, 
processes, and control technologies that reduce pollutant emissions.

VI. Statutory and Executive Order Reviews and 1 CFR Part 51

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 14094: Modernizing Regulatory Review

    This action is a ``significant regulatory action'' as defined under 
section 3(f)(1) of Executive Order 12866, as amended by Executive Order 
14094. Accordingly, the EPA submitted this action to the OMB for 
Executive Order 12866 review. Documentation of any changes made in 
response to the Executive Order 12866 review is available in the 
docket. The EPA prepared an analysis of the potential costs and 
benefits associated with this action. This analysis, ``Regulatory 
Impact Analysis for the Proposed Standards of Performance for New 
Stationary Sources and Emission Guidelines for Existing Sources: Large 
Municipal Waste Combustors,'' can be found in the docket for this 
action.
    Table 10 of this preamble presents the estimated PV and EAV of the 
projected health benefits, compliance costs, and net benefits of the 
proposed rule in 2022 dollars discounted to 2023. The estimated 
monetized net benefits are the projected monetized benefits minus the 
projected monetized costs of the proposed rule.
    In assessing the potential costs and benefits of its actions, EPA 
includes all potential costs and benefits, and not just those that stem 
from the regulated pollutants. Moreover, as explained in detail in the 
RIA, it is not possible to monetize the vast majority of the public 
health benefits associated with reductions of HAP. Accordingly, the 
projected monetized health benefits include those related to public 
health associated with projected reductions in fine PM 
(PM2.5) and ozone concentrations. The projected health 
benefits are associated with several point estimates and are presented 
at real discount rates of 3 and 7 percent. There are no changes in 
emissions from climate pollutants such as carbon dioxide 
(CO2) as determined in the analysis of secondary air impacts 
in section IV.B of the preamble. Thus, there are no climate benefits or 
disbenefits to be accounted for in the estimates of benefits for this 
proposal. The compliance costs are represented in this analysis as the 
costs of control technologies and measures applied to meet the 
emissions limits in the proposed policy scenario described earlier in 
this preamble. In simple terms, these costs are an estimate of the 
increased expenditures for large MWCs to implement the proposed 
requirements.
    These results present an incomplete overview of the potential 
effects of the proposal because important categories of benefits--
including benefits from reducing Hg and non-Hg metal HAP and the 
benefits from increased transparency of emissions--were not monetized 
and are therefore not reflected in the benefit-cost tables. We 
anticipate that taking non-monetized effects into account would show 
the proposal to have a greater net benefit than this table reflects.

    Table 10--Projected Monetized Benefits, Compliance Costs, and Net
               Benefits of the Proposed Rule, 2025 to 2044
       [Millions of 2022 dollars, discounted to 2023 dollars] \a\
------------------------------------------------------------------------
                                   3% Discount rate    7% Discount rate
------------------------------------------------------------------------
PV:
    Health benefits c d.........  $5,100 and $16,000  $3,100 and $9,800.
    Compliance costs............  $1,700............  $1,200.
    Net benefits................  $3,400 and $14,000  $1,800 and $8,500.
EAV: \b\
    Health benefits c d.........  $340 and $1,100...  $290 and $920.
    Compliance costs............  $110..............  $120.
    Net benefits................  $230 and $970.....  $170 and $800.
------------------------------------------------------------------------
\a\ Values have been rounded to two significant figures. Rows may not
  appear to sum correctly due to rounding.
\b\ The annualized present value of costs and benefits are calculated
  over the 20-year period from 2025 to 2044. The choice of this analysis
  period is explained in the RIA for the proposal.
\c\ The projected monetized benefits include those related to public
  health associated with reductions in PM2.5 and ozone concentrations.
  The projected health benefits are associated with several point
  estimates and are presented at real discount rates of 3 and 7 percent.
\d\ Several categories of benefits remain unmonetized and are thus not
  reflected in the table. Non-monetized benefits include important
  benefits from reductions in HAP including Cd, Pb, and PCDD/PCDF
  emissions. In addition, benefits to provision of ecosystem services
  associated with reductions in nitrogen and sulfur deposition and ozone
  concentrations are not monetized.

    As shown in Table 10 of this preamble, at a 3 percent discount 
rate, this proposed rule is projected to reduce PM2.5 and 
ozone concentrations, producing a projected PV of monetized health 
benefits of about $5.1 billion and $16 billion, with an EAV of about 
$340 million and $1.1 billion discounted at 3 percent. The PV of the 
projected compliance costs are $1.7 billion, with an EAV of about $110 
million discounted at 3 percent. Combining the projected benefits with 
the compliance costs yields a net benefit PV estimate of $3.4 billion 
and $14 billion and an EAV of $250 million and $1.0 billion.
    At a 7 percent discount rate, this proposed rule is expected to 
generate projected PV of monetized health benefits of $3.1 billion and 
$9.8 billion, with an EAV of about $290 million and

[[Page 4265]]

$920 million. The PV of the projected compliance costs are $1.2 
billion, with an EAV of $120 million discounted at 7 percent. Combining 
the projected benefits with the projected compliance costs yields a net 
benefit PV estimate of $1.8 billion and $8.5 billion and an EAV of $170 
million and $800 million.
    The potential benefits from reducing Hg and non-Hg metal HAP were 
not monetized and are therefore not reflected in the benefit-cost 
estimates associated with this proposal. Potential benefits from PCDD/
PCDF emission reductions and reduced nitrogen and sulfur deposition are 
not monetized in this analysis and are therefore not directly reflected 
in the quantified benefit-cost comparisons. We anticipate that taking 
these non-monetized effects into account would show the proposal to 
have a greater net benefit.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to the OMB under the PRA. The Information 
Collection Request (ICR) documents that the EPA prepared has been 
assigned EPA ICR number 1847.10 for subpart Cb (OMB Control number 
2060-0390) and 1506.15 for subparts Ea and Eb (OMB Control number 2060-
0210). You can find a copy of the ICR for each subpart in the docket 
for this rule, and they are briefly summarized here.
    These regulations apply to facilities that own and operate MWC 
units with a combustion capacity greater than 250 tpd of MSW that were 
constructed on or before September 20, 1994 (subject to 40 CFR 60, 
subpart Cb), facilities for which construction is commenced after 
December 20, 1989 and on or before September 20, 1994 (subject to 40 
CFR 60, subpart Ea), or for which construction is commenced after 
September 20, 1994 or for which modification or reconstruction is 
commenced after June 19, 1996 (subject to 40 CFR 60, subpart Eb). The 
reporting and recordkeeping requirements discussed below result from 
the EG that apply to large MWCs covered by the EPA-approved and 
effective state plans and, where a state plan has not been approved, 
large MWCs covered by the Federal plan, and large MWCs subject to the 
NSPS. This information is being collected to ensure compliance with 40 
CFR part 60, subparts Cb and Eb. In general, all EG and NSPS require 
initial notifications, performance tests, and periodic reports by the 
owners or operators of the affected facilities. They are also required 
to maintain records of the occurrence and duration of any SSM in the 
operation of an affected facility, or any period during which the 
monitoring system is inoperative. These notifications, reports, and 
records are essential in determining compliance, and are required of 
all affected facilities subject to EG or NSPS.
    The proposed amendments to the EG and NSPS would remove SSM 
exclusions and exceptions. These proposed amendments would also 
streamline regulatory language, revise recordkeeping, and require 
electronic reporting requirements; re-establish new and existing source 
applicability dates; clarify requirements for air curtain incinerators; 
correct certain typographical errors; make certain technical 
corrections and clarify certain provisions in the NSPS and EG. See 
section 4 of the Supporting Statement to the ICR for these proposed 
amendments in the docket to this rulemaking for more details.
    For the proposed amendments to the EG in 40 CFR part 60, subpart 
Cb, the EPA is also proposing to revise all emission limits, except CO 
for two combustor subcategories. Similarly, for the proposed amendments 
to NSPS 40 CFR part 60, subpart Eb, the EPA is proposing to revise all 
emission limits.
    Because EPA is proposing to revise applicability dates and 
ultimately reserve subpart Ea, the burden associated with units 
currently subject to subparts Ea and Eb has been combined with the 
burden for those currently subject to subpart Cb. The EPA does not 
anticipate any construction of new units or NSPS-triggering 
reconstruction or modifications of existing units within the next 3 
years.
    Respondents/affected entities: Existing large MWC units constructed 
on or before January 23, 2024, or that are reconstructed or modified 
prior to the date 6 months after promulgation of any revised final 
standards.
    Respondent's obligation to respond: Mandatory (40 CFR 60, subparts 
Cb, Ea, and Eb).
    Estimated number of respondents: 57.
    Frequency of response: Annual.
    Total estimated burden: 980 hours (per year). Burden is defined at 
5 CFR 1320.3(b).
    Total estimated cost: $100,000 (per year), includes no annualized 
capital or operation and maintenance costs.
    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 the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to [email protected], Attention: Desk Officer for the 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after receipt, OMB must receive comments no 
later than February 22, 2024. The EPA will respond to any ICR-related 
comments in the final rule.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. We have 
estimated that no small entities would be affected by the proposed 
changes to the EG and NSPS. For more information, please refer to the 
RIA for the proposed rule.

D. Unfunded Mandates Reform Act of 1995 (UMRA)

    This action may contain a Federal mandate under UMRA, 2 U.S.C. 
1531-1538, that may result in expenditures of $100 million or more for 
state and local governments, in the aggregate, and on the private 
sector. As explained in section VI.F, this action does not impose 
specific requirements on tribal governments. As a result of these 
potential impacts to governmental entities and the private sector, the 
EPA initiated consultation with these entities. The EPA also held 
meetings described in section VI. E of this preamble under Federalism 
consultation.

E. Executive Order 13132: Federalism

    The EPA has concluded that this action has federalism implications 
under EPA policy for implementing E.O. 13132, Federalism, because the 
rule imposes substantial direct compliance costs on state or local 
governments, and the Federal government will not provide the funds 
necessary to pay those costs. The EPA conducted a Federalism/UMRA 
consultation outreach briefing on March 16, 2023. Invited participants 
included representatives from the National Governors Association, the 
National Conference of State Legislatures, the Council of State 
Governments, the National League of Cities, the U.S. Conference of 
Mayors, the National Association of Counties, the International City/
County Management Association, the National

[[Page 4266]]

Association of Towns and Townships, the County Executives of America, 
and the Environmental Council of States to request their input on this 
rulemaking. Additionally, the Agency invited representatives from the 
National Association of Clean Air Agencies, the Association of Air 
Pollution Control Agencies, the Association of State and Territorial 
Solid Waste Management Officials, and other groups representing state 
and local government professionals. The purpose of the consultation was 
to provide general background on the rulemaking, answer questions, and 
solicit input from these national associations' state and local 
government members. Due to interest in this action, additional outreach 
meetings were held on April 17, 2023, and April 27, 2023, and included 
local government representatives of both the U.S. Conference of Mayors 
and the Waste To Energy Association, respectively. Subsequent to the 
outreach meetings, the EPA received letters from multiple 
organizations. These letters were submitted to the pre-proposal non-
rulemaking docket. See Docket ID No. EPA-HQ-OAR-2022-0920. A detailed 
Federalism Summary Impact Statement (FSIS) describing the most pressing 
issues raised in pre-proposal and post-proposal comments will be 
forthcoming with the final action, as required by section 6(b) of 
Executive Order 13132. In the spirit of E.O. 13132, and consistent with 
EPA policy to promote communications between state and local 
governments, the EPA specifically solicits comment on these proposed 
actions 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. The EPA is not aware of any large MWC unit owned 
or operated by tribal governments. During the development of this 
action, the EPA offered pre-proposal government-to-government 
consultation with Tribal Nations. No Tribal Nations requested 
consultation with the EPA. This action will not have substantial direct 
costs or impacts 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 proposed amendments. Consistent with the EPA Policy on Consultation 
and Coordination with Indian Tribes, the EPA will offer post-proposal 
government-to-government consultation with all federally recognized 
tribes.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 as applying to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because it does not concern an environmental 
health risk or safety risk.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' because the 
proposed amendments are not likely to have a significant adverse effect 
on the supply, distribution, or use of energy. There would be no change 
in energy consumption resulting from the proposed amendments, and the 
EPA does not expect any price increase for any energy type. We also 
expect that there would be no impact on the import of foreign energy 
supplies, and no other adverse outcomes are expected to occur with 
regards to energy supplies.

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    This rulemaking involves technical standards. Therefore, the EPA 
conducted searches through the Enhanced National Standards System 
Network Database managed by the American National Standards Institute 
(ANSI) to determine if there are voluntary consensus standards (VCS) 
that are relevant to this action. The Agency also contacted VCS 
organizations and accessed and searched their databases.
    We conducted searches for EPA Methods 1, 3A, 3B, 5, 6, 6A, 6C, 7, 
7A, 7C, 7D, 7E, 9, 10, 10A, 10B, 19, 22, 23, 26, 26A, 29 of 40 CFR part 
60, Appendix A. No applicable voluntary consensus standards were 
identified for EPA Methods 6C, 7D, 7E, 19 and 22.
    During the search, if the title or abstract (if provided) of the 
VCS described technical sampling and analytical procedures that are 
similar to the EPA's reference method, the EPA considered it as a 
potential equivalent method. All potential standards were reviewed to 
determine the practicality of the VCS for these rules. This review 
requires significant method validation data which meet the requirements 
of EPA Method 301 for accepting alternative methods or scientific, 
engineering and policy equivalence to procedures in the EPA reference 
methods. The EPA may reconsider determinations of impracticality when 
additional information is available for particular VCS.
    Three voluntary consensus standards were identified as an 
acceptable alternative to EPA test methods for the purposes of these 
rules.
    The EPA proposes to allow use of the manual portion only and not 
the instrumental portion of voluntary consensus standard ANSI/ASME PTC 
19-10-1981 Part 10 (2010), ``Flue and Exhaust Gas Analyses'' as an 
acceptable alternative to EPA Methods 3B, 6, 6A, 6B, 7, 7C. This method 
is available at the American National Standards Institute (ANSI), 1899 
L Street NW, 11th Floor, Washington, DC 20036 and the American Society 
of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016-
5990. See https://www.ansi.org and https://www.asme.org. The standard 
is available to everyone at a cost determined by ANSI/ASME ($96). The 
cost of obtaining this method is not a significant financial burden, 
making the methods reasonably available.
    The EPA proposes to allow the use of the voluntary consensus 
standard ASTM D7520-16, ``Standard Test Method for Determining the 
Opacity of a Plume in the Outdoor Ambient Atmosphere'' as an acceptable 
alternative to EPA Method 9 only if the following conditions are 
followed:

    1. During the digital camera opacity technique (DCOT) 
certification procedure outlined in Section 9.2 of ASTM D7520-16, 
you or the DCOT vendor must present the plumes in front of various 
backgrounds of color and contrast representing conditions 
anticipated during field use such as blue sky, trees, and mixed 
backgrounds (clouds and/or a sparse tree stand).
    2. You must also have standard operating procedures in place 
including daily or other frequency quality checks to ensure the 
equipment is within manufacturing specifications as outlined in 
Section 8.1 of ASTM D7520-16.
    3. You must follow the record keeping procedures outlined in 40 
CFR 63.10(b)(1) for the DCOT certification, compliance report, data 
sheets, and all raw unaltered JPEGs used for opacity and 
certification determination.
    4. You or the DCOT vendor must have a minimum of 4 independent 
technology users apply the software to determine the visible opacity 
of the 300 certification plumes. For each set of 25 plumes, the user 
may not exceed 15 percent opacity of anyone reading and the average 
error must not exceed 7.5 percent opacity.

[[Page 4267]]

    5. This approval does not provide or imply a certification or 
validation of any vendor's hardware or software. The onus to 
maintain and verify the certification and/or training of the DCOT 
camera, software, and operator in accordance with ASTM D7520-16 and 
conditions 1 to 4 above is on the facility, DCOT operator, and DCOT 
vendor.

    This method is available at ASTM International, 1850 M Street NW, 
Suite 1030, Washington, DC 20036. See https://www.astm.org. The 
standard is available to everyone at a cost determined by ASTM ($90). 
The cost of obtaining this method is not a significant financial 
burden, making the method reasonably available.
    The EPA proposes to allow the use of the voluntary consensus 
standard ASTM D6784-16, ``Standard Test Method for Elemental, Oxidized, 
Particle-Bound and Total Mercury Gas Generated from Coal-Fired 
Stationary Sources (Ontario Hydro Method)'' (D6784-16 was reapproved in 
2016 to include better quality control than earlier 2008 version) as an 
acceptable alternative to EPA Method 29 (portion for Hg only) as a 
method for measuring Hg. Note that this approval applies to 
concentrations approximately in the range of 0.5 to 100 micrograms per 
standard cubic meter ([mu]g/Nm\3\). This method is available at ASTM 
International, 1850 M Street NW, Suite 1030, Washington, DC 20036. See 
https://www.astm.org. The standard is available to everyone at a cost 
determined by ASTM ($82). The cost of obtaining this method is not a 
significant financial burden, making the method reasonably available.
    In addition, for the purpose of this rule, the EPA proposes to 
allow the use of facility operator certification method ASME QRO-1-2005 
(R2015), Standard for the Qualification and Certification of Resource 
Recovery Facility Operators. The 1995 rule cited a certification for 
facility operator ASME QRO-1-1994. Since that time, ASME has released a 
2005 version as the most recent one available. This method is available 
at the American Society of Mechanical Engineers (ASME), Three Park 
Avenue, New York, NY 10016-5990. See https://www.asme.org. The standard 
is available to everyone at a cost determined by ASME ($59). The cost 
of obtaining this method is not a significant financial burden, making 
the methods reasonably available.
    Additional information for the VCS search and determinations can be 
found in the memorandum, Voluntary Consensus Standard Results for Large 
Municipal Waste Combustors NSPS and EG, which is available in the 
docket for this action (Docket ID No. EPA-HQ-OAR-2017-0183).
    Under 40 CFR 60.8(b) and 60.13(i) of subpart A of the General 
Provisions, a source may apply to the EPA to use alternative test 
methods or alternative monitoring requirements in place of any required 
testing methods, performance specifications or procedures in the final 
rule or any amendments. The EPA welcomes comments on this aspect of the 
proposed rulemaking and, specifically, invites the public to identify 
potentially applicable VCS and to explain why such standards should be 
used in these regulations.
    The EPA is incorporating by reference the VCS ANSI/ASME PTC 19.10-
1981 Part 10 (2010), ``Flue and Exhaust Gas Analyses'' as an acceptable 
alternative to EPA Method 3B, 6, 6A, 6B, 7, 7C. for the determination 
of oxygen content (manual procedures only); the VCS ASTM D7520-16, 
``Standard Test Method for Determining the Opacity of a Plume in the 
Outdoor Ambient Atmosphere'' as an acceptable alternative to EPA Method 
9 only if certain conditions are followed as described above; and the 
VCS ASTM D6784-16, ``Standard Test Method for Elemental, Oxidized, 
Particle-Bound and Total Mercury in Flue Gas Generated from Coal-Fired 
Stationary Sources (Ontario Hydro Method),'' as an acceptable 
alternative to EPA Method 29 (Hg portion only) as a method for 
measuring Hg. Further, the EPA is incorporating by reference facility 
operator certification method ASME QRO-1-2005 (R2015), ``Standard for 
the Qualification and Certification of Resource Recovery Facility 
Operators,'' as an updated certification to the 1994 version that has 
been incorporated by reference in the current rules.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations and 
Executive Order 14096: Revitalizing Our Nation's Commitment to 
Environmental Justice for All

    The EPA believes that the human health or environmental conditions 
that exist prior to this action result in or have the potential to 
result in disproportionate and adverse human health or environmental 
effects on communities with environmental justice concerns. As stated 
in Section IV.F. of this preamble, the locations of the new, modified, 
and reconstructed sources that will become subject to the proposed 
large MWC NSPS (40 CFR 60, subpart Eb) are not known. Therefore, to 
examine the potential for any EJ issues that might be associated with 
the proposed NSPS, we performed a proximity demographic analysis for 
the 57 existing large MWC facilities that are currently subject to 40 
CFR part 60, subparts Cb, Ea and Eb. These characterize populations 
near existing facilities that might modify or reconstruct in the future 
and become subject to the proposed NSPS requirements.
    For large MWCs, a total of 3.9 million people live within 5 
kilometers (approximately 3.1 miles) of existing facilities. The 
proportion of demographic groups living near large MWC facilities are 
above the national average, include African American, Hispanic or 
Latino and other/multiracial populations. The proportion of other 
demographic groups living within 5 kilometers of large MWC facilities 
is similar or lower than the national average. See section IV.F for an 
analysis that characterizes populations living in proximity of 
facilities and risks prior to the proposed regulation.
    The EPA believes that this action is likely to reduce existing 
disproportionate and adverse effects on communities with environmental 
justice concerns. While the locations of the new, modified, and 
reconstructed sources that will become subject to the proposed large 
MWC NSPS (40 CFR 60 subpart Eb) are not known, this action proposes to 
establish standards for large MWC emission sources that will enhance 
protection for these populations by reducing pollutant emissions at 
future modified and reconstructed sources and minimizing future 
emission increases resulting from new sources. The proposed amendments 
to the EG and NSPS would also remove exclusions and exceptions from 
compliance during periods of SSM.
    The EPA additionally identified and addressed EJ concerns by 
engaging in outreach activities to communities we expect to be impacted 
most by the rulemaking (see section II.F).
    The information supporting this Executive Order review is contained 
in Section IV.G of this preamble. The demographic analysis is presented 
in the document Analysis of Demographic Factors for Populations Living 
Near Large Municipal Waste Combustors, which is available in the docket 
for this action.

List of Subjects in 40 CFR Part 60

    Environmental protection, Air pollution control, Hazardous 
substances, Incorporation by reference,

[[Page 4268]]

Reporting and recordkeeping requirements.

Michael S. Regan,
Administrator.
[FR Doc. 2024-00747 Filed 1-22-24; 8:45 am]
BILLING CODE 6560-50-P`