[Federal Register Volume 88, Number 164 (Friday, August 25, 2023)]
[Rules and Regulations]
[Pages 58442-58494]
[FR Doc No: 2023-16747]

Vol. 88

Friday,

No. 164

August 25, 2023

Part II

Environmental Protection Agency

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40 CFR Part 60

New Source Performance Standards Review for Steel Plants: Electric Arc
Furnaces and Argon-Oxygen Decarburization Vessels; Final Rule

Federal Register / Vol. 88 , No. 164 / Friday, August 25, 2023 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2002-0049; FRL-8150-01-OAR]
RIN 2060-AU96

New Source Performance Standards Review for Steel Plants:
Electric Arc Furnaces and Argon-Oxygen Decarburization Vessels

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing
amendments to the new source performance standards (NSPS) for electric
arc furnaces (EAF) and argon-oxygen decarburization (AOD) vessels in
the steel industry pursuant to the review required by the Clean Air
Act.

DATES:
    Effective date: This final rule is effective August 25, 2023. The
incorporation by reference of certain publications listed in the rule
is approved by the Director of the Federal Register as of August 25,
2023.
    Compliance dates: Affected sources that commence construction,
reconstruction, or modification after May16, 2022, must comply with all
requirements of 40 CFR part 60, subpart AAb no later than August 25,
2023 or upon startup, whichever is later. The date for complying with
the changes in the current rules, 40 CFR part 60, subparts AA and AAa
is February 21, 2024 publication of the final rule. The date for
complying with the ERT submission requirements is February 21, 2024.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2002-0049. All documents in the docket are
listed on the https://www.regulations.gov website. 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 form. Publicly available docket materials are available
electronically through https://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Donna Lee Jones, Sector Policies and
Programs Division (D243-02), P.O. Box 12055, Office of Air Quality
Planning and Standards, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina 27711; telephone number:<PHONE_NUMBER>;
and email address: [email protected].

SUPPLEMENTARY INFORMATION:
    Preamble acronyms and abbreviations. Throughout this document 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:

A/C air-to-cloth
ANSI American National Standards Institute
AOD argon-oxygen decarburization
ASME American Society of Mechanical Engineers
BACT best available control technology
BID background information document
BLDS bag leak detection systems
BPT benefits per ton
BSER best system of emissions reduction
CAA Clean Air Act
CBI confidential business information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emission monitoring systems
CFR Code of Federal Regulations
CO carbon monoxide
COMS continuous opacity monitoring systems
DCOT digital camera opacity technique
DEC direct shell evacuation control
EAF electric arc furnace
EIA economic impact assessment
EJ environmental justice
E.O. executive order
EPA Environmental Protection Agency
ERT electronic reporting tool
FR Federal Register
FRED Federal Reserve Economic Data
GASP Group Against Smog and Pollution
gr grains
gr/dscf grans per dry standard cubic feet
HAP hazardous air pollutants
ICR information collection request
II&S integrated iron and steel industry
ISA Integrated Science Assessment for Particulate Matter
LAER Lowest Achievable Emission Rate
lb pounds
lb/ton pounds per ton
mg/dscm milligrams per dry standard cubic meters
NAICS North American Industry Classification System
NAPCTAC National Air Pollution Control Technical Advisory Committee
NOX nitrogen oxides
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PDF portable document format
PM particulate matter
PM2.5 particulate matter less than 2.5 micrometers
PRA Paperwork Reduction Act
PS performance specification
RACT reasonably available control technology
RFA Regulatory Flexibility Act
RIN regulatory information number
SMA Steel Manufacturers Association
SSM startup, shutdown, and malfunction
tpy tons per year
UMRA Unfunded Mandates Reform Act of 1995
U.S. United States
U.S.C. United States Code
VCS voluntary consensus standard
VE visible emissions

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related
information?
    C. Judicial Review and Administrative Review
II. Background
    A. What is the statutory authority for this final action?
    B. How does the EPA perform the NSPS review?
    C. What is the source category regulated in this final action?
    D. What outreach and engagement did the EPA conduct?
III. What changes did we propose for the steel plants: Electric Arc
Furnaces (EAF) and argon-oxygen decarburization vessels NSPS?
    A. Standards of Performance for Steel Plants: Electric Arc
Furnaces and Argon-Oxygen Decarburization Vessels Constructed,
Reconstructed, or Modified After May 16, 2022
    B. Proposed Changes to Current NSPS, 40 CFR Part 60, Subparts AA
and AAa
IV. What actions are we finalizing, and what is our rationale for
such decisions?
    A. NSPS Requirements for PM Emissions From Control Devices for
Electric Arc Furnaces and Argon-Oxygen Decarburization Vessels
Constructed After May 16, 2022
    B. NSPS Requirements for Opacity From Melt Shops for Electric
Arc Furnaces and Argon-Oxygen Decarburization Vessels Constructed
After May 16, 2022
    C. NSPS Requirements for Opacity From Control Devices and Dust
Handling for Electric Arc Furnaces and Argon-Oxygen Decarburization
Vessels Constructed After May 16, 2022
    D. Startup, Shutdown, Malfunctions Requirements for Electric Arc
Furnaces and Argon-Oxygen Decarburization Vessels Modified,
Reconstructed, or Constructed After May 16, 2022
    E. Testing and Monitoring Requirements for Electric Arc Furnaces
and Argon-Oxygen Decarburization Vessels
    F. Electronic Reporting
    G. Effective Date and Compliance Dates
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the air quality impacts?
    B. What are the secondary impacts?
    C. What are the cost impacts?

    D. What are the economic impacts?
    E. What are the benefits?
    F. What analysis of environmental justice did we conduct?
VI. Statutory and Executive Order Reviews
    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 (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 Populations and Low-Income
Populations
    K. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

    The source category that is the subject of this final action is
composed of steel manufacturing facilities that operate electric arc
furnaces (EAF) and argon-oxygen decarburization (AOD) vessels regulated
under CAA section 111 New Source Performance Standards (NSPS). The 2022
North American Industry Classification System (NAICS) code for the
source category is 331110 for ``Iron and Steel Mills and Ferroalloy
Manufacturing'' processes. The NAICS code serves as a guide for readers
outlining the type of entities that this final action is likely to
affect. The NSPS codified in 40 CFR part 60, subpart AAb are directly
applicable to affected facilities that begin construction,
reconstruction, or modification after May 16, 2022. Final amendments to
40 CFR part 60, subpart AA are applicable to affected EAF and AOD
facilities that begin construction, reconstruction, or modification
after October 21, 1974, and on or before August 17, 1983. Final
amendments to 40 CFR part 60, subpart AAa are applicable to affected
EAF and AOD vessels facilities that begin construction, reconstruction,
or modification after August 17, 1983, and on or before May 16, 2022.
Federal, state, local and Tribal government entities would not be
affected by this action. If you have any questions regarding the
applicability of this action to a particular entity, you should
carefully examine the applicability criteria found in 40 CFR part 60,
subparts AA, AAa, and AAb, and consult the person listed in the FOR
FURTHER INFORMATION CONTACT section of this preamble, your state air
pollution control agency with delegated authority for NSPS, or your EPA
Regional Office.

B. 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 final action is available on the internet at https://www.epa.gov/stationary-sources-air-pollution/electric-arc-furnaces-eafs-and-argon-oxygen-decarburization. Following publication in the Federal Register,
the EPA will post the Federal Register version of the final rule and
key technical documents at this same website.

C. Judicial Review and Administrative Review

    Under Clean Air Act (CAA) section 307(b)(1), judicial review of
this final action is available only by filing a petition for review in
the United States Court of Appeals for the District of Columbia Circuit
by October 24, 2023. Under CAA section 307(b)(2), the requirements
established by this final rule may not be challenged separately in any
civil or criminal proceedings brought by the EPA to enforce the
requirements.
    Section 307(d)(7)(B) of the CAA further provides that ``[o]nly an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review.'' This section also
provides a mechanism for the EPA to convene a proceeding for
reconsideration, ``[i]f the person raising an objection can demonstrate
to the EPA that it was impracticable to raise such objection within
[the period for public comment] or if the grounds for such objection
arose after the period for public comment, (but within the time
specified for judicial review) and if such objection is of central
relevance to the outcome of the rule.'' Any person seeking to make such
a demonstration to us should submit a Petition for Reconsideration to
the Office of the Administrator, U.S. Environmental Protection Agency,
Room 3000, WJC West Building, 1200 Pennsylvania Ave. NW, Washington, DC
20460, with a copy to both the person(s) listed in the preceding FOR
FURTHER INFORMATION CONTACT section, and the Associate General Counsel
for the Air and Radiation Law Office, Office of General Counsel (Mail
Code 2344A), U.S. Environmental Protection Agency, 1200 Pennsylvania
Ave. NW, Washington, DC 20460.

II. Background

A. What is the statutory authority for this final action?

    The EPA's authority for this final rule is CAA section 111, which
governs the establishment of standards of performance for stationary
sources. Section 111(b)(1)(A) of the CAA requires the EPA Administrator
to list categories of stationary sources that in the Administrator's
judgment cause or contribute significantly to air pollution that may
reasonably be anticipated to endanger public health or welfare. The EPA
must then issue performance standards for new (and modified or
reconstructed) sources in each source category pursuant to CAA section
111(b)(1)(B). These standards are referred to as NSPS. The EPA has the
authority to define the scope of the source categories, determine the
pollutants for which standards should be developed, set the emission
level of the standards, and distinguish among classes, types, and sizes
within categories in establishing the standards.
    CAA section 111(b)(1)(B) requires the EPA to ``at least every 8
years review and, if appropriate, revise'' NSPS. However, the
Administrator need not review any such standard if the ``Administrator
determines that such review is not appropriate in light of readily
available information on the efficacy'' of the standard. When
conducting a review of an existing performance standard, the EPA has
the discretion and authority to add emission limits for pollutants or
emission sources not currently regulated for that source category.
    In setting or revising a performance standard, CAA section
111(a)(1) provides that performance standards are to reflect ``the
degree of emission limitation achievable through the application of the
best system of emission reduction which (taking into account the cost
of achieving such reduction and any nonair quality health and
environmental impact and energy requirements) the Administrator
determines has been adequately demonstrated.'' The term ``standard of
performance'' in CAA section 111(a)(1) makes clear that the EPA is to
determine both the best system of emission reduction (BSER) for the
regulated sources in the source category and the degree of emission
limitation achievable through application of the BSER. The EPA must
then, under CAA section

111(b)(1)(B), promulgate standards of performance for new sources that
reflect that level of stringency. CAA section 111(b)(5) generally
precludes the EPA from prescribing a particular technological system
that must be used to comply with a standard of performance. Rather,
sources can select any measure or combination of measures that will
achieve the standard. CAA section 111(h)(1) authorizes the
Administrator to promulgate ``a design, equipment, work practice, or
operational standard, or combination thereof'' if in his or her
judgment, ``it is not feasible to prescribe or enforce a standard of
performance.'' CAA section 111(h)(2) provides the circumstances under
which prescribing or enforcing a standard of performance is ``not
feasible,'' such as, when the pollutant cannot be emitted through a
conveyance designed to emit or capture the pollutant, or when there is
no practicable measurement methodology for the particular class of
sources.
    Pursuant to the definition of new source in CAA section 111(a)(2),
standards of performance apply to facilities that begin construction,
reconstruction, or modification after the date of publication of the
proposed standards in the Federal Register. Under CAA section
111(a)(4), ``modification'' means any physical change in, or change in
the method of operation of, a stationary source which increases the
amount of any air pollutant emitted by such source or which results in
the emission of any air pollutant not previously emitted. Changes to an
existing facility that do not result in an increase in emissions are
not considered modifications. Under the provisions in 40 CFR 60.15,
reconstruction means the replacement of components of an existing
facility such that: (1) The fixed capital cost of the new components
exceeds 50 percent of the fixed capital cost that would be required to
construct a comparable entirely new facility; and (2) it is
technologically and economically feasible to meet the applicable
standards. Pursuant to CAA section 111(b)(1)(B), the standards of
performance or revisions thereof shall become effective upon
promulgation.

B. How does the EPA perform the NSPS review?

    As noted in section II. A of this preamble, CAA section 111
requires the EPA to, at least every 8 years review and, if appropriate,
revise the standards of performance applicable to new, modified, and
reconstructed sources. If the EPA revises the standards of performance,
they must reflect the degree of emission limitation achievable through
the application of the BSER considering the cost of achieving such
reduction and any nonair quality health and environmental impact and
energy requirements. CAA section 111(a)(1).
    In reviewing an NSPS to determine whether it is ``appropriate'' to
revise the standards of performance, the EPA evaluates the statutory
factors, which may include consideration of the following information:
     Expected growth for the source category, including how
many new facilities, reconstructions, and modifications may trigger
NSPS in the future.
     Pollution control measures, including advances in control
technologies, process operations, design or efficiency improvements, or
other systems of emission reduction, that are ``adequately
demonstrated'' in the regulated industry.
     Available information from the implementation and
enforcement of current requirements indicates that emission limitations
and percent reductions beyond those required by the current standards
are achieved in practice.
     Costs (including capital and annual costs) associated with
implementation of the available pollution control measures.
     The amount of emission reductions achievable through
application of such pollution control measures.
     Any nonair quality health and environmental impact and
energy requirements associated with those control measures.
    In evaluating whether the cost of a particular system of emission
reduction is reasonable, the EPA considers various costs associated
with the particular air pollution control measure or a level of
control, including capital costs and operating costs, and the emission
reductions that the control measure or particular level of control can
achieve. The Agency considers these costs in the context of the
industry's overall capital expenditures and revenues. The Agency also
considers cost-effectiveness analysis as a useful metric, and a means
of evaluating whether a given control achieves emission reduction at a
reasonable cost. A cost-effectiveness analysis allows comparisons of
relative costs and outcomes (effects) of 2 or more options. In general,
cost effectiveness is a measure of the outcomes produced by resources
spent. In the context of air pollution control options, cost
effectiveness typically refers to the annualized cost of implementing
an air pollution control option divided by the amount of pollutant
reductions realized annually.
    After the EPA evaluates the statutory factors, the EPA compares the
various systems of emission reductions and determines which system is
``best,'' and therefore represents the BSER. The EPA then establishes a
standard of performance that reflects the degree of emission limitation
achievable through the implementation of the BSER. In doing this
analysis, the EPA can determine whether subcategorization is
appropriate based on classes, types, and sizes of sources, and may
identify a different BSER and establish different performance standards
for each subcategory. The result of the analysis and BSER determination
leads to standards of performance that apply to facilities that begin
construction, reconstruction, or modification after the date of
publication of the proposed standards in the Federal Register. Because
the NSPS reflect the best system of emission reduction under conditions
of proper operation and maintenance, in doing its review, the EPA also
evaluates and determines the proper testing, monitoring, recordkeeping
and reporting requirements needed to ensure compliance with the
emission standards.

C. What is the source category regulated in this final action?

    The EPA first promulgated NSPS under CAA section 111 for EAF at
steel plants source category on September 23, 1975 (40 FR 43850). These
standards of performance are codified in 40 CFR part 60, subpart AA and
are applicable to sources that commence construction, modification, or
reconstruction after October 21, 1974, and on or before August 17,
1983. These standards of performance regulate emissions of particulate
matter (PM) from EAF capture systems and control devices with a PM
concentration limit of 12 milligrams per dry standard cubic meter (mg/
dscm) [0.0052 grains per dry standard cubic feet (gr/dscf)] and set
opacity limits for using capture technology controlling EAF melt shop
emissions, which include, but are not limited to, emissions via roof
vents, doors, and cracks in walls of 6 percent opacity, with 20 percent
and 40 percent opacity allowed during charging and tapping,
respectively; control device exhaust at 3 percent opacity due to proper
operation of control devices; and dust handling procedures due to
proper handling of captured PM at 10 percent opacity.
    In 1984, the NSPS rule, 40 CFR part 60, subpart AA (for EAF
constructed

after October 21, 1974, and on or before August 17, 1983) was reviewed
and revised as part of NSPS statutory review (49 FR 43838; October 31,
1984). The 1984 action amended 40 CFR part 60, subpart AA to include
AOD and raise the melt shop opacity from 0 percent to 6 percent
opacity, keeping the exceptions for charging (20 percent opacity) and
tapping (40 percent opacity). The 1984 action also codified a new NSPS
subpart, 40 CFR part 60, subpart AAa, to regulate EAF and AOD vessels
that commenced construction after August 17, 1983 (49 FR 43843). The
NSPS codified at 40 CFR part 60, subpart AAa set requirements for melt
shop opacity at 6 percent with no exceptions. Finally, the 1984 action
promulgated requirements to include EPA Method 5D (Appendix A to 40 CFR
part 60) for the determination of PM emissions from positive-pressure
fabric filters, which are common control devices for EAF and AOD
vessels for both 40 CFR part 60, subparts AA and AAa.
    On February 14, 1989, 40 CFR part 60, subparts AA and AAa (and
Appendix A to 40 CFR part 60) were amended to consolidate the EPA test
methods and delete repetitions of methods already referenced (54 FR
6672). Then, on May 17, 1989, minor clarifications and corrections were
made to the February 1989 revisions (54 FR 21344). On March 2, 1999, as
a result of recommendations made by the EPA's sector policy established
in 1994,\1\ called the ``Common Sense Initiative,'' 40 CFR part 60,
subparts AA and AAa were amended to add an option to monitor furnace
static pressure instead of melt shop opacity and to monitor baghouse
(fabric filter) fan amperage instead of baghouse flowrate (64 FR
10109). On October 17, 2000, amendments were made to 40 CFR part 60,
subparts AA and AAa to promulgate Performance Specification (PS) 15 for
certifying continuous emission monitoring systems (CEMS) with Fourier
transform infrared spectroscopy (FTIR); to reformat various methods as
per recommendations by the Environmental Monitoring Management Council;
and to make miscellaneous clarifications and technical and editorial
corrections (65 FR 61758). On February 22, 2005, 40 CFR part 60,
subparts AA and AAa were amended in response to a petition by the
American Iron and Steel Institute, Steel Manufacturers Association
(SMA), and Specialty Steel Industry of North America to add bag leak
detection systems (BLDS) as an alternative monitoring method to the
continuous opacity monitoring systems currently cited in the rules (70
FR 8523).
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    \1\ See Analysis and Evaluation of the EPA Common Sense
Initiative. Prepared by: Kerr Greiner, Andersen, and April, Inc.
Funded by the U.S. Environmental Protection Agency under PO No. No.
9W-0753-NTSA. 1999. Available at https://NEPIS.epa.gov.
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    An EAF is a metallurgical furnace used to produce carbon and alloy
steels. The input material to an EAF is typically almost 100 percent
scrap steel. Cylindrical, refractory-lined EAF are equipped with carbon
electrodes to be raised or lowered through the furnace roof. With
electrodes retracted, the furnace roof can be rotated to permit
charging scrap steel into the EAF by overhead crane. Alloying agents
and fluxing materials usually are added through doors on the side of
the furnace. Electric current is passed between the electrodes and
through the scrap, producing an arc and generating enough heat to melt
the scrap steel charge. After the melting and refining periods,
impurities (in the form of slag \2\) and the refined steel are poured
from the furnace, in a process called ``tapping.'' If AOD vessels are
present, they follow the EAF in the production sequence and are used to
oxidize carbon, silicon, and impurities, such as sulfur. For these
reasons, the AOD vessels reduce additions of alloying material compared
to an EAF alone. Use of AOD vessels also reduce EAF heat times, improve
quality control, and increase daily steel production. AOD vessels are
primarily used in stainless steel making.
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    \2\ Slag is the molten metal oxides and other impurities that
float to the surface of the molten steel product.
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    The production of steel in an EAF is a batch process. Cycles, also
called heats, range from about 1.5 to 5 hours to produce carbon steel
and from 5 to 10 hours to produce alloy steel. Scrap steel is charged
to begin a cycle, with alloying agents and slag forming materials added
later in the process for refining purposes. The stages of each cycle
normally include charging, melting, refining (which also usually
includes oxygen blowing), and tapping, all of which generate PM
emissions.
    Air emission control techniques typically involve an air emission
capture system and a gas cleaning system. The air emission capture
systems used in the EAF industry include direct shell evacuation
control (DEC) systems, side draft hoods, combination hoods, canopy
hoods, scavenger ducts, and furnace enclosures. The DEC system consists
of ductwork attached to a separate opening, or ``fourth hole,'' in the
furnace roof (top) that draws emissions from the furnace to a gas
cleaner and which works only when the furnace is up-right and the roof
is in place. Side draft hoods collect furnace exhaust gases from around
the electrode holes and work doors after the gases leave the furnace.
Combination hoods incorporate elements from the side draft and direct
shell evacuation systems. Canopy hoods and scavenger ducts are used to
address charging and tapping emissions. Baghouses, also called fabric
filters, are typically used as gas cleaning systems (i.e., emissions
control devices).
    There are approximately 88 EAF in the United States (U.S.), with
most (>95 percent) EAF subject to one of the EAF NSPS subparts. Thirty-
one states have one or more EAF facilities, with most of the EAF
facilities east of the Mississippi River. Pennsylvania (15), Ohio (10),
Alabama (7), and Indiana (7) have the most EAF facilities per state
(approximate number of EAF facilities in each state).
    The EPA proposed amendments to the NSPS subparts AA and AAa, and a
new subpart AAb, based on the current review on May 16, 2022 (87 FR
29710). We received 11 comments from industry, environmental groups,
state environmental agencies, and others during the comment period. A
summary of the more significant comments we timely received regarding
the proposed rule and our responses are provided in this preamble. A
summary of all other public comments on the proposal and the EPA's
responses to those comments is available in the document Summary of
Public Comments and Responses for Standards of Performance for Steel
Plants: Electric Arc Furnaces Constructed After October 21, 1974, and
On or Before August 17, 1983; and Standards of Performance for Steel
Plants: Electric Arc Furnaces and Argon-Oxygen Decarburization Vessels,
Docket ID No. EPA-HQ-OAR-2002-0049 located in the docket for this rule.
In this action, the EPA is finalizing decisions and revisions pursuant
to CAA section 111(b)(1)(B) review for Steel Plants: Electric Arc
Furnaces (EAF) and Argon-Oxygen Decarburization Vessels NSPS (40 CFR
part 60, subpart AAa) after our considerations of all the comments
received.

D. What outreach and engagement did the EPA conduct?

    As part of this rulemaking, and pursuant to multiple Executive
Orders addressing environmental justice, the EPA engaged and consulted
with the public, including populations of overburdened communities and
low-income populations, through interactions, such as a letter sent on

May 17, 2022, to 40 leaders of Tribal nations (see Docket ID No. EPA-
HQ-OAR-2002-0049). The EPA received comments from the following
environmental groups during the comment period: Group Against Smog and
Pollution (GASP), Fairfield Environmental Justice Action Coalition
(FEJA), Sierra Club, California Communities Against Toxics, and Greater
Birmingham Alliance to Stop Pollution, et al. These opportunities gave
the EPA a chance to hear from the public, especially communities
potentially impacted by this final action.
    Some of the key issues raised by environmental justice stakeholders
included a specific area of the country where there are PM problems and
where there are 2 EAF facilities; and regulating other pollutants, such
as sulfur dioxide (SO2) and greenhouse gases (GHG). Section
V of the preamble provides a description of how the Agency considered
these comments in the context of regulatory development.

III. What changes did we propose for the Steel Plants: Electric Arc
Furnaces (EAF) and Argon-Oxygen Decarburization Vessels NSPS?

    On May 16, 2022, the EPA proposed the results of the review of the
EAF and AOD source category standards of performance to determine if
revisions were warranted pursuant to CAA section 111(b)(1)(B).
    Pursuant to this review, we proposed to revise the NSPS for EAF and
AOD vessels. We also proposed several clarifications and corrections to
existing NSPS rules (40 CFR part 60, subparts AA and AAa). These
proposed actions are discussed below in sections III.A and III.B. We
also proposed: periodic compliance testing at least once every 5 years;
results of the review of opacity from control device exhaust and from
dust handling systems to keep same BSER and limits as in 40 CFR part 6,
subpart AAa of 3 percent and 10 percent, respectively; that the
emission limits would apply at all times; and electronic reporting.

A. Standards of Performance for Steel Plants: Electric Arc Furnaces and
Argon-Oxygen Decarburization Vessels Constructed, Reconstructed, or
Modified After May 16, 2022

1. Analyses To Determine BSER for Melt Shop Opacity and PM Emissions
From Control Devices
    The EPA proposed to determine that the use of a baghouse with a
fabric filter is the BSER for EAF and AOD vessels. The EPA proposed
that a limit of at 0.16 pounds (lb) PM emitted per ton steel produced
(lb/ton) reflects the degree of emission limitation achievable through
application of the BSER. The EPA also proposed to determine using a
partial roof canopy to control visible fugitive emissions (VE) from EAF
and AOD in the melt shop is BSER. The EPA proposed that a limit of 0
percent opacity during all phases of EAF operation reflects the degree
of emission limitation achievable through application of the BSER.
    The BSER and proposed standards of performance for PM emissions
from capture systems and fabric filters, and for capture of emissions
from melt shops was developed from an analysis of EAF PM test reports
from 2005 through 2017 obtained by the EPA. The PM data contained in
these reports reflected 33 facilities, 46 EAF, 5 AOD, and 54 baghouses
in 154 emission and opacity tests (hereafter referred to as the ``EAF
dataset''). The EAF dataset showed a substantial improvement in EAF,
AOD, and baghouse performance beyond the current NSPS PM standards (40
CFR part 60, subparts AA, AAa) for control devices as well as for melt
shop opacity. The costs of control, emissions reductions, and other
factors were used in the determination of BSER, as explained in next
sections.
a. BSER for Melt Shop Opacity
    From the EAF dataset described earlier in this preamble, the EPA
identified 15 EAF facilities, approximately half of the EAF dataset,
that reported 0 percent melt shop opacity. To determine BSER and its
costs to reduce melt shop opacity at EAF facilities from 6 percent to 0
percent opacity, the costs for an addition of a partition roof canopy
(above the crane rails) were estimated for the proposal. Canopy hoods
are a common method of controlling fugitive EAF emissions. In the
proposal cost analysis, we estimated that the annual costs would be
$800,000 ($2020 \3\) for a medium-sized steelmaking EAF with
installation of a partition roof canopy (above the crane rails). With
an estimated PM reduction of 730 tpy to achieve 0 percent melt shop
opacity down from the current 6 percent opacity (in 40 CFR part 60,
subparts AA, AAa), the cost effectiveness in $2020 was estimated to be
$1,100 per ton PM removed ($2020). Similar results were obtained for
both small and large EAF. Based on the BSER analysis as explained at
proposal, the EPA proposed that BSER for melt shop is a partition roof
canopy (above the crane rails) and proposed in 40 CFR part 60, subpart
AAb to revise the opacity limit to 0 percent to limit visible emissions
from EAF and AOD that exit from the melt shop during all phases of
operation.
---------------------------------------------------------------------------

    \3\ The cost analyses for the 2022 proposal used a 3.25 percent
interest rate. Federal Reserve Economic Data (FRED). Bank Prime Loan
Rate Changes: Historical Dates of Changes and Rates. Available at:
https://fred.stlouisfed.org/series/PRIME. Accessed 11/6/2020.
---------------------------------------------------------------------------

b. Capture System, Baghouse, and Facility-Wide Total PM Control Device
Emission Limit
    The EPA proposed as the BSER a capture system and fabric filter.
For the standard, we proposed a facility-wide mass-based PM limit from
all EAF and AOD capture systems and control devices of 0.16 lb total PM
per ton steel instead of a PM concentration limit that applies to each
capture system and control device, which is the format of the current
standards in 40 CFR part 60, subparts AA, AAa. As explained in the
proposal, the EPA proposed a facility-wide mass-based PM limit because
this form of standard was thought to result in better overall PM
control and provide greater assurance of limiting PM emissions from the
facility. Most importantly, if EAF emissions can be divided up into
separate baghouses, for practical purposes or otherwise, with each
device falling under the same NSPS PM limit based on air flow in gr/
dscf, there is no accounting for the total PM emissions from the
facility. A facility-wide total control device PM emissions limit in
units of lb PM/ton of steel produced was expected to eliminate the
disparity in control device emissions between low- and high-PM
concentration exhaust, such as that for control devices for primary
emissions (i.e., directly from the EAF or AOD) v. secondary emissions
(i.e., from fugitive emissions), as well as the disparity between well-
operated v. inefficiently-operated control devices in the cases where
both types of control devices operate below the current individual
baghouse limit in 40 CFR part 60, subparts AA, AAa.
    To evaluate the BSER to reduce emissions from EAF and AOD capture
systems and control devices, the EPA evaluated the baghouse air-to-
cloth (A/C) ratio, expressed in units of volume of air flow per unit
bag area (i.e., cloth), using EAF facility baghouse model plants
developed from the EPA dataset describe earlier in this preamble (87 FR
29718-29720). This was done to evaluate BSER, of which cost is a
factor. The A/C ratio is generally accepted as the most important
design parameter between baghouses of different performance levels,
where a low A/C

ratio is considered to be the best level of control (less air and more
baghouse filter cloth) and a high A/C ratio is a low or poor level
control (high air volume and low baghouse filter area).
    Using model plants developed from the EAF dataset and the EPA cost-
estimating procedures,\4\ an A/C ratio of 2.2 m/min (7.2 ft/min)
leading to a value of 0.16 lb total PM per ton steel produced was
determined to be cost effective (87 FR29710). For a medium-sized model
plant consisting of an EAF and all its baghouses, i.e., EAF facility,
emitting 0.16 lb PM/ton steel produced, the cost effectiveness at this
lb/ton level was approximately $1,800 per ton PM removed $2020, an
acceptable cost effectiveness, with an incremental cost effectiveness
compared to a model plant at the next higher level of control (A/C
ratio of 4.9 ft/min) at $8,500/ton $2020, which was not considered
reasonable. Similar results were obtained for small and large EAF.
Therefore, a facility-wide total 0.16 lb PM/ton steel produced limit
from capture systems and control devices was proposed to represent
performance level for the BSER for EAF and AOD capture systems and
fabric filters for 40 CFR part 60, subpart AAb.
---------------------------------------------------------------------------

    \4\ Cost Analyses to Determine BSER for PM Emissions and Opacity
from EAF Facilities. D.L. Jones, U.S. Environmental Protection
Agency, Office of Air Quality Planning and Standards, Research
Triangle Park, North Carolina, and G.E. Raymond, RTI International,
Research Triangle Park, North Carolina. May 1, 2023 (Docket ID No.
EPA-OAR-2002-0049).
---------------------------------------------------------------------------

2. Requirement for Compliance Testing Every Five Years
    We proposed that sources complying with 40 CFR part 60, subpart AAb
would be required to perform compliance testing every 5 years after the
initial testing performed upon startup, as required under 40 CFR part
60.8. This requirement already is required in many of the permits for
existing EAF in the EAF dataset and in the industry, and also is a
standard requirement for testing for other sources of PM emissions for
many other industrial sectors.
3. Review of EAF NSPS Standards for Opacity From EAF Control Devices
and Dust Handling Systems
    The current NSPS standards for EAF in 40 CFR part 60, subparts AA
and AAa, require less than 3 percent opacity from control device
(baghouse) exhaust and less than 10 percent for dust handling
procedures. We proposed to retain these limits in 40 CFR part 60,
subpart AAb. (87 FR 29720-29721). In reviewing the EAF dataset, the EPA
based these limits on the fact that no facilities reported lower levels
of opacity for these sources, nor were lower levels required in any
permits for these or any other EAF facilities. In addition,
commensurate with determinations reported in the RACT/BACT/LAER
Clearinghouse,\5\ the current levels for baghouse exhaust (9
facilities) and dust handling systems (3 facilities) in 40 CFR part 60,
subparts AA, AAa were considered BACT. Therefore, we concluded in the
proposal that the opacity standards for control device exhaust and dust
handling systems would remain the same.
---------------------------------------------------------------------------

    \5\ See https://www.epa.gov/catc/ractbactlaerclearinghouse-rblc-basic-information for more information. RACT, or reasonably
available control technology, is required on existing sources in
areas that are not meeting national ambient air quality standards
(i.e., nonattainment areas); BACT, or best available control
technology, is required on major new or modified sources in clean
areas (i.e., attainment areas); and LAER, or lowest achievable
emission rate, is required on major new or modified sources in
nonattainment areas. See the RACT/BACT/LAER determinations made for
EAF in the cost memorandum prepared for proposal (03-01-22); Docket
ID No. EPA-HQ-OAR-2002-0049-0060.
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4. Startup, Shutdown, Malfunction Exemption Removal From 40 CFR Part
60, Subpart AAb
    The NSPS general provisions (40 CFR 60.11(c)) currently exclude
opacity requirements during periods of startup, shutdown and
malfunction (SSM). We proposed that opacity limits in 40 CFR part 60,
subpart AAb would apply at all times along with all other emissions
limits and standards, as provided in 40 CFR 60.11(f), because we
concluded in the proposal that there were no technical limitations
known to prevent new, reconstructed, or modified facilities from
meeting all standards at all times. The language overriding the general
provisions SSM opacity exemption was proposed for 40 CFR part 60,
subpart AAb at 40 CFR 60.272b(c).
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008), the United States Court of Appeals for the District of
Columbia Circuit vacated portions of two provisions in the EPA's CAA
section 112 regulations governing the emissions of HAP during periods
of SSM. Specifically, the court vacated the SSM exemption contained in
40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section
302(k) of the CAA, emissions standards or limitations must be
continuous in nature and that the SSM exemption violates the CAA's
requirement that some CAA section 112 standards apply continuously. The
EPA has determined the reasoning in the court's decision in Sierra Club
applies equally to CAA section 111 because the definition of emission
or standard in CAA section 302(k), and the embedded requirement for
continuous standards, also applies to the NSPS. Therefore, consistent
with Sierra Club, we proposed the NSPS standards in the 40 CFR part 60,
subpart AAb would apply at all times.
5. Electronic Reporting for 40 CFR Part 60, Subparts AA, AAa, and AAb
    The EPA proposed the requirement that owners and operators of EAF
and AOD subject to the current and new NSPS at 40 CFR part 60, subparts
AA, AAa, and AAb submit electronic copies of required performance test
reports and any semiannual excess emissions and continuous monitoring
system performance and summary reports, through the EPA's Central Data
Exchange (CDX) using the Compliance and Emissions Data Reporting
Interface (CEDRI). The proposed rule required that performance test/
demonstration of compliance results collected using test methods that
are supported by the EPA's Electronic Reporting Tool (ERT) as listed on
the ERT website \6\ 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/
demonstration of compliance results be submitted in portable document
format (PDF) using the attachment module of the ERT.
---------------------------------------------------------------------------

    \6\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For semiannual reports, the proposed rule required that owners and
operators use the appropriate spreadsheet template to submit
information to CEDRI. The final versions of the templates for these
reports are included in the docket for this action.\7\ Additionally,
the EPA identified the circumstances in which electronic reporting
extensions may be provided.
---------------------------------------------------------------------------

    \7\ See 40 CFR part 60, subpart AA, AAa, and AAb, Standards of
Performance for Steel Plants: Electric Arc Furnaces and Argon-Oxygen
Decarburization Vessels, 40 CFR part 60.276(g) Semiannual Compliance
Report Spreadsheet Template, available at Docket ID No. EPA-HQ-OAR-
2002-0049-0064.
---------------------------------------------------------------------------

B. Proposed Changes to Current NSPS, 40 CFR Part 60, Subparts AA and
AAa

    We proposed the following amendments and requested comments on the
existing NSPS rules for EAF, 40 CFR part 60, subpart AA, and EAF and
AOD, 40 CFR part 60, subpart AAa, to update, correct, or clarify these
rules to enhance compliance and enforcement.
     Amendments to clarify and refine the rule requirements in
40 CFR part 60, sections 60.271 and 60.271a ``Definitions'', 60.272 and
60.272a

``Standard for particulate matter'', 60.273 and 60.273a ``Emission
monitoring'', 60.274a ``Monitoring of operations'', 60.275a ``Test
methods and procedures'', and 60.276a ``Recordkeeping and reporting
requirements''.
     Minor revisions to clarify the rule and enhance compliance
and enforcement.
     Solicited comments, data, and other information on whether
the EPA should change the time to both find and fix the cause of a BLDS
alarm from 3 hours to a longer timeframe (e.g., 24 hours as in other
rules), or some other duration.
     Requirement that owners and operators of EAF facilities
submit electronic copies of required performance test/demonstration of
compliance reports and semiannual reports through the EPA's CDX using
the CEDRI and ERT.
     Requirement that performance test/demonstration of
compliance results collected using test methods that are supported by
the EPA's ERT as listed on the ERT website \8\ 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/demonstration of compliance results be submitted
in PDF using the attachment module of the ERT.
---------------------------------------------------------------------------

    \8\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

     For semiannual reports, requirement that owners and
operators use the appropriate spreadsheet template to submit
information to CEDRI.

IV. What actions are we finalizing, and what is our rationale for such
decisions?

    The EPA is finalizing revisions to the NSPS for EAF and AOD at
steel plants pursuant the CAA section 111(b)(1)(B) review. The EPA is
promulgating the NSPS revisions in a new subpart, 40 CFR part 60,
subpart AAb that are applicable to affected facilities constructed,
modified, or reconstructed after May 16, 2022. The new subpart reflects
a BSER for a PM capture system and fabric filter, and a total facility
limit for PM from control devices in units of lb PM/ton steel produced,
and a canopy hood to capture melt shop VE, and a 0 percent opacity
limit during melting and refining.
    We also are finalizing results of the review of opacity from
control device exhaust and from dust handling systems to keep same BSER
and limits as in 40 CFR part 60, subpart AAa of 3 percent and 10
percent, respectively; that the emission limits would apply at all
times; periodic compliance testing at least once every 5 years; and
electronic reporting.
    The facility-wide PM limit of 0.16 lb/ton as finalized will apply
to all EAF and AOD control devices subject to 40 CFR part 60, subpart
AAb and also all the air pollution control equipment used to remove
particulate matter from the effluent gas stream generated by the EAF
and AOD. The melt shop opacity standard of 0 percent as finalized will
apply during the melting and refining period, and a 6 percent opacity
limit will apply during the charging period and during the tapping
period, with daily opacity or VE testing required during all 3 periods.
We are finalizing that the PM limit of 0.16 lb/ton standard apply at
all times, including during SSM, and that an opacity limit will also
apply at all times (i.e., 6 percent opacity during charging and tapping
and 0 percent opacity at all other times). We are finalizing the
requirement to submit the required compliance test reports through CDX
using CEDRI and the ERT.
    We also are finalizing clarifications and corrections to the 2
existing EAF rules: 40 CFR 60 subpart AA, Standards of Performance for
Steel Plants: Electric Arc Furnaces Constructed After 10/21/74 & On or
Before 8/17/83; and 40 CFR 60 subpart AAa, Standards of Performance for
Steel Plants: Electric Arc Furnaces & Argon-Oxygen Decarburization
Constructed After 8/17/83 and On or Before May 16, 2022. For these
rules, we are finalizing amendments to certain parts of the current
NSPS standards and to allow 24 hours for owners and operators a find
and fix the cause of a BLDS alarm.

A. NSPS Requirements for PM Emissions From Control Devices for Electric
Arc Furnaces and Argon-Oxygen Decarburization Vessels Constructed After
May 16, 2022

1. What did we propose as the BSER determination and standard of
performance for PM emissions from EAF control devices?
    We proposed that BSER for new, modified, and reconstructed EAF and
AOD sources is a capture system and fabric filter. We proposed that the
PM limit that reflects BSER is a total facility emission rate of 0.16
lb PM/ton of steel from control devices at an affected facility. The
EPA proposed a facility-wide mass-based PM limit from all EAF and AOD
control devices per ton of steel produced instead of a PM concentration
limit based on mass of PM per control device air flow that applies to
each control device, which is the format of the standards in 40 CFR
part 60, subparts AA, AAa.
2. What significant comments did we receive and what are our responses?
    Comment: One commenter asserted that the form of the standard
should not be changed from the original form of the standard in NSPS
subpart AAa. The commenter stated for the NSPS subpart AAa rulemaking,
the EPA rejected a production-based (or mass-based) standard in favor
of a concentration-based limit in a NSPS proposed rule that was
published on August 17, 1983. The commenter notes that, in that 1983 FR
document, the EPA stated:
    ``A process weight format is based on a direct relationship between
the quantity of pollutant emitted and the amount of input material
consumed or product produced. Because of wide differences between EAF
and AOD shops in operating procedures, such as the length of the steel
production cycle, grade of steel produced, control technologies, vessel
capacities, and other operating parameters, a simple direct
relationship between mass emissions and steel production does not
exist. Therefore, a process weight format was not selected for control
devices regulated by the proposed standards.''
    ``Methodology to measure the concentration of emissions discharged
to the atmosphere from control devices is readily available and well
demonstrated. Concentration measurements are obtained directly from the
stack emission test data. A concentration standard can be met equally
well by a large or a small shop and by carbon and specialty steel
shops. Consequently, a concentration format (i.e., mass emissions per
unit volume of gas) was selected for control devices regulated by the
proposed standards to ensure control of captured process and fugitive
emissions.'' (48 FR 37347)
    The commenter continued that the EPA provides no explanation for
the change in its position and fails to address the rationale the
Agency provided in 1983 for adopting the current grain-loading
standards in NSPS subpart AA and NSPS subpart AAa.
    Another commenter added that the EPA's failure to justify this
``depart[ure] from a prior policy'' would render abandonment of the
current concentration-based standard ``arbitrary and capricious,''
citing to FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515-16
(2009).
    EPA Response: The EPA disagrees with the comment that the EPA did
not provide an adequate explanation for changing the form of the
standard from

concentration-based to a production-based limit. The new format of the
EAF NSPS subpart AAb, in units of lb/ton, ensures compliance as well as
ensures that every facility is accountable for the total PM
contribution from its EAF to the environment in the nearby community
for every unit of steel produced. The EPA fully explained its
justification for use of lb/ton format in the 2022 proposal, as follows
here.
    In the 2022 proposal, we explained that the emissions, and, hence,
collected PM, from baghouses that control only secondary emissions can
be much lower than the other two types of baghouses, as seen in the EAF
dataset where the baghouse with the lowest PM emissions controlled only
secondary emissions (87 FR 29715). We also explained that because of
the inherent lower baghouse PM input (loading), secondary baghouses can
be operated inefficiently without exceeding the current NSPS limit,
which is expressed in the units of mass PM per unit of control device
exhaust air. In addition, where there is a standard in terms of mass PM
per unit of total exhaust air, baghouse dilution air (added to EAF
exhaust air) can be increased with the effect of lowering measured
baghouse PM emission concentration and disguising the true performance
of the baghouse.
    Further, at 87 FR 29715, the EPA proposed to set a facility-wide PM
limit instead of a limit that applies to each control device (the
format of the current standard) because we think this form of standard
will result in better control and provide greater assurance of
compliance. Most importantly, if EAF emissions can be divided up into
separate baghouses, for practical purposes or otherwise, with each
device falling under the same NSPS PM limit, there is no accounting for
the total PM emissions from the facility. A facility-wide total control
device PM emissions limit in units of lb of PM per ton of steel
produced also would alleviate the potential disparity in control device
emissions between low-and high-loading control devices, such as that
for control devices for primary v. secondary emissions, as well as for
well-operated v. inefficiently-operated control devices that both
operate below the individual baghouse limit (87 FR 29715). Therefore,
we did adequately explain our change in position at the proposal and
also explained why we now think a facility-wide limit is more
protective than a concentration-based limit, thereby satisfying the
standard in Fox Television. See 556 U.S. at 515-16 (when the Agency
acknowledges change in position, ``it suffices that the new policy is
permissible under the statute, that there are good reasons for it, and
that the Agency believes it to be better, which the conscious change of
course adequately indicates'').
    The commenter did not include any current data showing the lack of
a direct relationship between mass emissions and steel production. The
graphs in Figure 1 from the memorandum titled Particulate Matter
Emissions from Electric Arc Furnace Facilities,\9\ hereafter called the
``Emissions Memorandum,'' show a similar curve shape when data for the
total EAF facility average concentration of PM in gr/dscf from the 2010
EPA/EAF data set \10\ are plotted compared to the same PM data
expressed as lb/ton PM emissions.
---------------------------------------------------------------------------

    \9\ Particulate Matter Emissions from Electric Arc Furnace
Facilities. D.L. Jones, U.S. Environmental Protection Agency, Office
of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, and G.E. Raymond, RTI International, Research Triangle
Park, North Carolina. May 1, 2023. (Docket ID No. EPA-OAR-2002-0049-
0061).
    \10\ In 2010, the EPA acquired EAF data from approximately 30
EAF facilities via a CAA section 114 test and information request.
These data are located in the docket for the EAF NESHAP, 40 CFR part
63, subpart YYYYY at https://www.regulations.gov/docket/EPA-HQ-OAR-2004-0083 and incorporated by reference into the docket for the EAF
NSPS at https://www.regulations.gov/docket/EPA-HQ-OAR-2002-0049.
[GRAPHIC] [TIFF OMITTED] TR25AU23.000

    In 1973, the EPA originally presented a NSPS standard in units of
lb/hr-ton during the National Air Pollution Control Technical Advisory
Committee (NAPTAC) meeting when the EAF NSPS was first being developed,
as described in the 1974 Background Information for Standards of
Performance \11\ (BID). On February 22, 1973, the Agency presented to
the National Air Pollution Control Techniques Advisory Committee
(NAPCTAC) a draft standard PM limitation of 0.06 lb/hr-ton. However,
this standard was ultimately not used by the EPA for the NSPS because
of the industry objections with the lb/ton format and interest in the
concentration-based limit.
---------------------------------------------------------------------------

    \11\ Background Information for Standards of Performance:
Electric Arc Furnaces in the Steel Industry, Volume 1: Proposed
Standards. Publication No. EPA-450/2-74-017a. U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, North Carolina (October 1974).
---------------------------------------------------------------------------

    It should be noted that the first promulgated NSPS limit, at 0.0052
gr/dscf, was based on test data from only

one facility, as described in the 1974 BID \12\ for EAF under 40 CFR
part 60, subpart AA, the original EAF NSPS.
---------------------------------------------------------------------------

    \12\ Background Information for Standards of Performance:
Electric Arc Furnaces in the Steel Industry, Volume 1: Proposed
Standards. Chapter V. Summary of the Procedure For Developing
Standards, Section D, Plant Inspections. Publication No. EPA-450/2-
74-017a. U.S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, North Carolina
(October 1974. pg. 63 (pdf pg. 88)).
---------------------------------------------------------------------------

    Preliminary investigations for the NSPS identified 30 plants from a
review of the literature and contacts with industry, a described in the
1974 BID, discussed earlier in this section. From these 30 plants, 11
plants were identified that reportedly were well-controlled for PM
emissions. Ten of the 11 facilities were visited, their visible
emissions evaluated, and information obtained on the process and
control equipment. Although many of the 11 plants practiced good
control techniques, the facilities at only 3 plants (Plants A, I and J)
were amenable to testing with EPA Method 5. Other facilities were not
suitable for emission measurements because they use positive pressure
baghouses, which have no stacks. Although development work was in
progress, sampling methodology for this type of installation had not
been standardized. These 3 plants were nearly identical except for
size. They all produced alloy steels and controlled PM emissions with a
building evacuation system. Each had a fabric filter control device
that exhausted through multiple stacks. Rather than spread the test
program effort over 3 tests at nearly identical plants, it was decided
a more comprehensive test of one plant would provide more information.
The middle-sized plant offered the best possibilities for this
comprehensive test. Its size was typical of the mid-range for the
industry, and the fabric filter did not have an inordinately large
number of exhaust stacks.
    To show that a mass-based limit has been considered by the EPA
previously, the chronological history of the EAF NSPS subpart AA and
AAa standards for PM from control devices, as taken from the 1974 BID,
discussed earlier in this section, is as follows:
     In 1972, 299 EAF's in the United States were operated by
99 companies at 121 locations. On February 22, 1973, the Agency
presented to the NAPCTAC a draft standard PM limitation of 0.06 pound
per hour-ton (lb/hr-ton). Steel industry representatives attending the
meeting suggested that the PM standard should be 0.244 lb/hr-ton.
     On May 30 and 31, 1973, at another NAPCTAC meeting, the
EPA presented a revised draft technical report and standard. The PM
standard presented by the EPA was changed from 0.06 lb/hr-ton to 0.10
lb/hr-ton. The industry representatives at the meeting suggested that
the standard be expressed on a concentration basis and be set at 0.008
grains per dry standard cubic feet (gr/dscf) for a dry collector (e.g.,
baghouse or fabric filter) and 0.02 gr/dscf for a wet collector
(scrubber).
     At the January 9, 1974, NAPCTAC meeting, available
emission data indicated that a 0.0039 gr/dscf PM standard could be
easily achieved. These data were supported by a vendor guarantee of
0.004 gr/dscf on fabric filters at 3 building evacuation systems at 3
similar shops. These shops, owned by one company at one location,
produced alloy steel. Another vendor also signed a statement that they
would guarantee 0.004 gr/dscf on a system planned for the capture of
charging and tapping emissions at a plant which produced carbon steel.
Two other vendors stated that although 0.004 gr/dscf was achievable for
fabric filters designed to treat large volumes of exhaust gas with low
concentrations of PM, it could not be guaranteed, but 0.004 gr/actual
cubic feet (acf), approximately equivalent to 0.005 gr/dscf, could be
guaranteed. Further, industry representatives at the meeting commented
that the 0.0039 gr/dscf level was too stringent for the industry to
meet at all times. Therefore, the industry representatives suggested
the limitation be 0.008 gr/dscf.
     After the January 9, 1974, NAPCTAC meeting, a vendor
stated that, for a fabric filter controlling a direct shell evacuation
(DEC) system with a relatively high inlet concentration of PM, 0.005
gr/dscf was a reasonable level to guarantee.
     In the October 21, 1974 proposal (39 FR 37466), the Agency
proposed a PM standard to be no more than 0.0052 gr/dscf of PM from the
control device, which relaxed the previous presented value of 0.0039
gr/dscf for the limit for the PM concentration emitted from an EAF
control device.
    In summary, this history of discussions around the first PM limit
for EAF control devices in the NSPS is as follows: the EPA originally
put forward an EAF control device standard in the form of lb/hr-ton in
1973. The following year, industry suggested a PM limit of 0.008 gr/
dscf and vendors presented a guaranteed fabric filter limit of 0.005
gr/dscf. Subsequently, in 1974, the EPA proposed a standard of 0.0039
gr/dscf, which was based on ``available emission data'' from one
facility, as noted in the 1974 BID. However, after NAPCTAC discussions
with industry and vendors, a limit of 0.0052 gr/dscf was promulgated by
the EPA in 1975 in the EAF NSPS subpart AA and confirmed again in 1984
in the EAF NSPS subpart AAa.
    Regardless of the EPA's discussions during prior rulemakings, as
detailed in the proposed rule and in this final action, we now have a
strong basis to find a direct relationship between mass emissions and
steel production that justifies our facility-wide PM limit in units of
lb/ton. We show in our analyses of 2010 data from 30 facilities
discussed in this preamble (see Figure 1), as well as in data from more
facilities from 2005, as discussed in another EPA response in this
preamble section, that there is a direct relationship. As explained
earlier in section IV.A.1 and in other comments in this section, and in
the proposal, the EPA analyzed the total facility PM mass emissions
versus production at a number of EAF facilities and found that a
correlation exists, and that promulgating a PM standard for NSPS
subpart AAb in this form would enhance compliance and may reduce
emissions. As noted earlier in this EPA response, the new format of the
EAF NSPS subpart AAb, in units of lb/ton ensures that every facility is
accountable for the total PM contribution from its EAF and AOD to the
environment in the nearby community for every unit of steel produced.
As an example of similar thoughts on the value of EAF standards in lb/
ton, we note a 2017 facility construction permit for prevention of
significant deterioration that included a lb/ton PM limit (0.19 lb/
ton), as well as a ``no visible emissions'' limit for the EAF.\13\
---------------------------------------------------------------------------

    \13\ Finkl & Sons Co. DBA Finkl Steel--Chicago. 1355 East 93rd
Street, Chicago, Illinois 60619. State of Illinois Clean Air Act
Permit Program (CAAPP) Permit. ID No. 031600GUC. Permit No.
14030029. Permitting Authority, Illinois Environmental Protection
Agency Bureau of Air, Permit Section 217/785-1705. Final issue date
July 5, 2018. pp. 21 and 23 of 129.
---------------------------------------------------------------------------

    Comment: The commenter asserted that the EPA conducted evaluation
on a concentration basis and not in the form of the proposed standard
(lb/ton). A commenter stated the EPA in its proposal performed cost
analyses based upon the air flowrates to the air pollution control
device, and rather than establishing a standard of performance for the
air pollution control device (baghouse), the EPA proposed the PM
emissions standard in terms of lb/ton steel produced on a facility-wide
basis. The EPA analyzed the performance of emissions controls from EAF
on a concentration basis (milligram per dry standard cubic meters (mg/

dscm)--grain per dry standard cubic feet (gr/dscf))--and not in the
form of the proposed standard. The EPA must be consistent with the
basis of its evaluation and establish a standard measuring compliance
as a concentration exiting the control device.
    EPA Response: The commenter correctly notes that, rather than
establishing a concentration standard of performance for each
individual air pollution control device (baghouse), the EPA in 2022
proposed to set the PM emissions standard in terms of lb/ton steel
produced on a facility-wide basis from all control devices at the EAF
facility. However, the EPA disagrees that we analyzed the performance
of emissions controls from EAF on a concentration basis (gr/dscf)--and
not in the form of the proposed standard. The EPA's analysis in the
``Emissions Memorandum'' discussed earlier in this section clearly
demonstrates that the EPA evaluated costs and emission reductions on a
facility-wide basis in lb/ton format. [See figures and tables in the
``Emissions Memorandum'' discussed earlier in this section: Figure 3
(EAF baghouse data in mass PM per mass of steel produced (lb/ton));
Figure 4 (EAF facility total baghouse mass PM per mass of steel
produced (lb/ton)); Table 3 (EAF Baghouse Information and Average PM
Emissions (lb/ton)); and Table 5 (Facility Total EAF Baghouse Average
PM Emissions (lb/ton))]. Further, the EPA outlined in multiple
locations in the proposal that the performance of emissions controls
from EAF were done on a facility-wide basis.
    For example, at 87 FR 29716, the EPA described the PM and opacity
test data that was used in the BSER analysis. At 87 FR 29715-29716, the
EPA explained how the opacity limit was developed considering facility-
wide emissions. To determine the PM limit for control device PM
emissions under the BSER, the EPA only used data from EAF facilities
with 0 percent melt shop opacity. This was because facilities that
control their melt shop opacity to 0 percent are collecting more PM
(specifically from the melt shop) than facilities that have a nonzero
melt shop opacity and, as a result, are sending more PM to their
control devices. Consequently, EAF facilities with 0 percent melt shop
opacity are expected to have a slightly higher control device PM
emission rate on average compared to EAF facilities with greater than 0
percent melt shop opacity, as evidenced by the EAF dataset of 33 EAF
facilities. As a corollary, at EAF facilities with 6 percent melt shop
opacity, some of the PM generated by the EAF is not captured, avoids
the control device, and can exit through the melt shop roof, thus
raising the melt shop opacity to above 0 percent. In turn, facilities
with 6 percent melt shop opacity collect less PM and, therefore, less
PM is sent to control device, which results in (slightly) lower PM
emissions in the control device exhaust.
    Overall, because of the large amount of PM emission differential
between 6 percent and 0 percent melt shop opacity, much less PM is
emitted to the environment with 0 percent melt shop opacity than with 6
percent opacity, despite the higher level of control device emissions
with 0 percent melt shop opacity. This effect is described
quantitatively in the proposal preamble (87 FR 29720). Of the 15 EAF
facilities in the EPA dataset with 0 percent melt shop opacity, control
device PM emissions data and steel production values needed to develop
an emission standard in mass of PM per mass of steel production were
available for 13 of the 15 facilities; these data included 51
individual tests from 23 baghouses and 21 EAF. The 13 EAF facilities
and their PM emissions were used to demonstrate that 0 percent melt
shop opacity is BSER and to develop a facility-wide total PM control
device emission standard in lb/ton under the BSER for new, modified,
and reconstructed EAF or AOD.
    As explained earlier in section IV.A.1 and other comments in this
section, and in the proposal, the EPA analyzed the total facility PM
mass emissions versus production at a number of EAF facilities and
found that a correlation exists, and that promulgating a PM standard
for NSPS subpart AAb in this form would enhance compliance and may
reduce emissions. As noted earlier in this EPA response, the new format
of the EAF NSPS subpart AAb, in units of pound per ton (lb/ton),
ensures that every facility is accountable for the total PM
contribution from its EAF to the environment in the nearby community
for every unit of steel produced.
    Comment: A commenter asserted that a lb/ton steel limit does not
consider the different types of EAF mills. A commenter stated the EPA
does not acknowledge nor address the fundamental fact that a
``facility-wide lb/ton'' production, or mass-based standard, ignores
the substantial differences among EAF steel mills that directly bear on
the PM emissions per ton of steel produced. The commenter claims it is
both unfair and inconsistent with the BSER to hold a small specialty
steel EAF facility, with low tonnages and more time-intensive steel
refining requirements, to the same production-based standard as a
facility that produces 10-times or more steel with much shorter heat
times (i.e., 2 facilities with vastly different production rates).
    The commenter stated a compliance method based on PM per ton of
steel produced does not take into consideration the various
subcategories of EAF operations, differences in steel products, and
variation in heat times and tonnages produced, which vary considerably
depending on the product grade of steel and the mix of such products at
various mills. Some carbon EAF mills produce high tonnages in
relatively short heat times, while specialty EAF steel facilities
produce much smaller tonnages over heat times that can be 2 to 3 times
as long.
    The commenter continued, as the EPA noted in developing the NSPS
subpart AAa standards in 1984, the production of steel in an EAF is a
batch process where `heats' or cycles range from 1 to 5 hours,
depending upon the size and quality of the charge, the power input to
the furnace, and the desired quality of the steel produced. The
commenter added, the EPA's statement in the proposal that ``[t]he
production of steel in an EAF is a batch process'' (87 FR 29713), is
not accurate and fails to acknowledge ``Endless Charging Systems'' and
Consteel[supreg] continuous feed systems (i.e., continuous charging
systems). The commenter added that, to determine appropriate standards
of performance, the EPA should conduct a comprehensive evaluation of
the different types of EAF mills (such as bar, sheet, and plate) and
consider establishing different limitations and requirements for each
subcategory. Another commenter encourages the EPA to evaluate current
designs and applications of baghouses for the control of PM.
    EPA Response: We disagree with the commenter on the relevance of
lb/ton standard to the variation in EAF operations. The lb/ton limit
being promulgated (0.16 lb/ton) reflects the highest emitting facility
in the EPA dataset, which is a stainless steel facility. Therefore, we
expect both EAF carbon and stainless steel facilities, continuous or
batch, that modify or reconstruct and then are subject to the NSPS
subpart AAb will be able to meet the new PM limit. Moreover, future
new, reconstructed, and modified facilities will be in an even better
position to meet this limit because they can plan their construction,
reconstruction, or modification accordingly. For these reasons, and
because the facility which represents the PM limit, at 0.16 lb/ton
total facility PM control device emissions, is the highest emitting
facility in the dataset

(and 1 of only a total of 4 steel facilities in the industry that
produce only stainless steel), we do not think a subcategory is
warranted.
    The commenter is correct that the lb/ton limit does not take into
account the different types of EAF mills, but the various types of
steel and production have all been meeting the single concentration
standard in subpart AAa (and AA) without issue in the many years since
this limit was first set in 1975. Therefore, meeting a lb/ton standard
based on the emissions of one third of the facilities in the industry
that also are meeting the current standard will not be a problem.
Whether a mill is batch or continuous, slow or fast, will not affect
the total amount of PM emitted per amount of steel produced for each
facility. When a batch process stops producing steel (i.e., stops
tapping steel), it typically also will stop emitting PM from the EAF.
If PM emissions continue after the EAF has stopped processing scrap, or
steel has stopped being tapped in a batch process, any ``trailing'' PM
emitted is still a result of the steel that has just been produced.
Therefore, this ``trailing'' PM should be included in the total PM
catch for the test run.
    Similarly, a continuous EAF process will emit PM as it continues to
produce steel. And a relatively large amount of steel produced in a
short time will also produce a relatively large amount of PM in a short
period. The effect of dividing the PM emitted by the tons of steel
produced normalizes the different processes to a common lb/ton term.
    Comment: Air-to-cloth (A/C) ratios from integrated iron and steel
(II&S) industry were used instead of EAF data. The commenter asserted
that the EPA offers no explanation why using II&S baghouse data was
relevant to EAF baghouse controls in the first place or why the EPA
presumed that relative rank placement of 5 facilities along a ranking
of II&S baghouse A/C ratios allowed the EPA to presume those
facilities' PM emissions were based on control through a baghouse with
the same A/C ratios. Moreover, the commenter asserts that the use of
II&S data is inexplicable because the EPA has in its possession the A/C
ratios for many plants with EAF. This information was available to the
EPA in the rulemaking docket for the 40 CFR part 63, subpart YYYYY
NESHAP for EAF, and the EPA even summarized the A/C ratios for the EAF
baghouses that were operated during these performance tests.
    The commenter continued to assert that the EPA's derived average,
median, minimum, and maximum A/C ratios are all incorrect. The derived
A/C ratios misstate the actual A/C ratios reported by the 3 model
facilities for which the EPA had actual performance test data (Model
Plants A, B, and E). For instance, Model Plant E is the North American
Stainless facility in Ghent, Kentucky (NAS-KY), which operates 4
baghouses. For those 4 baghouses, the facility reported to the EPA A/C
ratios of 4.1, 4.5, 4.5, and 5.0 ft/min--none of which are close to the
EPA's erroneously derived A/C ratio of 7.2 ft/min.
    EPA Response: The EPA disagrees with the commenter's assertion that
the use of II&S data in lieu of the A/C ratios for plants with EAF is
inappropriate. The EPA stated in the EAF NSPS proposal (87 FR 29718)
that the reason for using more recent 2011 II&S baghouse data was
because no A/C ratio data were available in the EAF PM test reports
from 2010. Therefore, values for A/C ratios from CAA section 114
responses submitted in 2011 by the II&S industry for the risk and
technology review for 40 CFR part 63, subpart FFFFF (85 FR 42074) were
used in the EAF BSER PM cost analysis. The baghouses used for emissions
from furnaces in the II&S industry are expected to be similar in
operation as the baghouses used at EAF/AOD for the purposes of this
analysis.
    The baghouse A/C ratios from in the NSPS proposal based on II&S
data submitted in 2011 for a CAA section 114 request were similar to
those submitted in 2005 for another CAA section 114 request for the EAF
NESHAP (40 CFR part 63, subpart YYYYY),\14\ as shown in Table 1. A
quantitative comparison of the A/C ratios from the 2005 EAF NESHAP data
to the II&S 2011 data is also shown in Table 1.
---------------------------------------------------------------------------

    \14\ Docket ID No. EPA-HQ-OAR-2004-0083.

                       Table 1--Comparing A/C Ratios for 2011 II&S Data v. 2005 EAF NESHAP
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
Model plant                                  A/C ratio (ft/min)
                              Comparing 2011 II&S A/C data to 2005 NESHAP data
                             --------------------------------------------------
                                            2011 II&S          2005 EAF NESHAP
----------------------------------------------------------------------------------------------------------------
A...........................                      1.3                      1.4  -7 percent.....  II&S lower.
B...........................                      2.9                      2.2  32 percent.....  II&S higher.
C...........................                      4.0                      3.0  33 percent.....  II&S higher.
D...........................                      4.9                      4.5  9 percent......  II&S higher.
E...........................                      7.2                        6  20 percent.....  II&S higher.
----------------------------------------------------------------------------------------------------------------
                                    Average                                     17 percent.....  II&S higher.
----------------------------------------------------------------------------------------------------------------

    As the commenter points out, the 2005 EAF data does not include all
of the facilities from the 2010 dataset. In addition, the 2005 data did
not have A/C data for all the facilities' baghouses, where there were
multiple baghouses, and for some facilities the number of baghouses for
each facility changed from 2005 to 2010.
    In response to this comment, for the final rule, we re-examined the
BSER analysis of total facility PM lb/ton steel from capture systems
and fabric filters using A/C ratios from the EAF 2005 CAA section 114
request that ranged from 1.4 to 6.0 ft/min. For Model Plant A,
corresponding to Timken-Faircrest-OH, the A/C ratio in the 2005 CAA
section 114 request (3.4 A/C) was higher than the 2011 II&S data point
(at 1.3 A/C), but the A/C ratio derived using a regression analysis
that produced the line of best fit from the 2005 CAA section 114
request data (at 1.4 A/C), is very similar to the II&S datapoint (1.3
A/C).
    For Model Plant B, based on Timken-Harrison-OH, the A/C ratio from
the 2005 CAA section 114 request (at 2.7 A/C) is very similar to the
II&S data point (2.9 A/C) and also from a regression analysis that
produced the line of best fit from 2005 (2.7 A/C).
    For Model Plant E, based on NAS-KY, an average A/C ratio of 4.5 ft/
min A/C was derived from the data reported to the EPA in 2010 (and also
provided by the commenter). However, the A/C ratio of 6.0 assigned to
the same emissions as

NAS-KY (0.16 lb/ton) derived from the curve of 2005 CAA section 114
data is not much different than what was used in the EAF proposal (at
7.2 A/C) based on II&S data. These values are shown in Table 2.

                                   Table 2--Comparing A/C Ratio Data Between 2005 and 2010 EAF Data and 2011 II&S Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                A/C ratio (ft/min)
                                       Comparing 2005 to 2010                            ---------------------------------------------------------------
              Facility                          data                  Model plant                                                           Curve using
                                                                                2011 II&S data   2005 EPA data   2010 EPA data     2005 data
--------------------------------------------------------------------------------------------------------------------------------------------------------
Timken-Faircrest-OH.................  Different baghouses....  A                                     1.3             3.4              NA             1.4
Timken-Harrison-OH..................  Same baghouses.........  B                                     2.9             2.7              NA             2.2
NAS-Ghent-KY........................  Same baghouses.........  E                                     7.2              NA             4.5             6.0
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In addition, the EPA used the data from the 2005 CAA section 114
request for the EAF NESHAP to add to the 2010 CAA section 114 request
data used for the lb/ton BSER PM limit analyses for capture systems and
fabric filters reported in the proposal in order to re-evaluate the
proposed lb/ton BSER standard for capture system and fabric filter PM
emissions. The 2005 EAF emission data that was able to be converted to
lb/ton values and also had A/C ratio data were used along with 2010 CAA
114 request data used to develop BSER for the proposal. A similar trend
in PM lb/ton data was seen in the 2005 data as compared to 2010 data,
as shown in Figure 2 below, with a lower maximum PM lb/ton value in the
2005 data.
    The 2010 CAA section 114 request data used to develop the PM lb/ton
standard for the proposal were matched to the A/C ratios in the 2005
CAA section 114 data for the NAS-Ghent-KY facility, to provide a total
of 18 facilities in the dataset for PM lb/ton standard for capture
systems and fabric filters for the final rule. See the memorandum
titled Cost Analyses to
[GRAPHIC] [TIFF OMITTED] TR25AU23.001

Determine BSER for PM Emissions and Opacity from EAF Facilities,\15\ as
updated for the final rule, hereafter referred to as the ``Cost
Memorandum,'' located in the docket for this rule. The results of the
analyses of a PM limit that reflects BSER were similar between proposal
and final producing the same PM 0.16 lb/ton limit for the BSER capture
system and fabric filter. See Table 3 for the combined 2005 and 2011
lb/ton data set using EAF A/C ratios and both 2005 and 2011 EAF
submitted emissions data. Table 4 shows the results from the model
plant analyses comparing the results for the 2 approaches. Note Model
Plants E and F are both the highest emitting model plant in the
proposal (using 2011 II&S A/C ratios) and final rule (Using 2005 EAF A/
C ratios) analyses, respectively. Because Model Plants E and F are the
highest emitting model plants, the EPA does not have a baseline with
which to compare the costs and emission reductions in order to develop
average cost effectiveness values. However, the EPA's determination of
the BSER in this review is consistent with its determination of the
BSER in the prior 40 CFR 60, subpart AAa rulemaking. And as noted
elsewhere in this preamble, a third of the industry is already
achieving the PM 0.16 lb/ton limit through application of that BSER,
which demonstrates that the costs of meeting that limit are reasonable,
and not exorbitant or excessive. See Lignite Energy Council v. EPA, 198
F.3d 930, 933 (D.C. Cir. 1999) (``EPA's choice will be sustained unless
the environmental

or economic costs of using the technology are exorbitant.''); Sierra
Club v. Costle, 657 F.2d 298, 343 (D.C. Cir. 1981) (the court is not
inclined to ``quarrel'' with the EPA's judgment that ``forecasted cost
was not excessive and did not make the cost of compliance with the
standard unreasonable''); Portland Cement Association v. Train, 513
F.2d 506, 508 (D.C. Cir. 1975) (the inquiry is whether the costs of the
standard are ``greater than the industry could bear and survive'').
Moreover, the capital costs and annual costs associated with compliance
with the PM 0.16 lb/ton limit are similar to, and in some cases lower
than, the costs that the EPA found to be reasonable for implementing
the BSER to meet the final opacity standard, discussed in section IV.B.
See the ``Cost Memorandum,'' discussed earlier in this section, for
details of both the canopy costs for the opacity limit and fabric
filter costs for the PM limit. This further demonstrates that the costs
of meeting the PM 0.16 lb/ton limit are also reasonable for this
industry, for all facility sizes. However, as shown in Table 4, the EPA
does not find the incremental costs of achieving the more stringent
standards evaluated through application of the BSER to be cost
effective for any facility size. Accordingly, the EPA concludes that PM
0.16 lb/ton limit reflects the degree of emission limitation achievable
through application of the BSER.
---------------------------------------------------------------------------

    \15\ Cost Analyses to Determine BSER for PM Emissions and
Opacity from EAF Facilities. D.L. Jones, U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, North Carolina, and G.E. Raymond, RTI
International, Research Triangle Park, North Carolina. May 1, 2023;
Docket ID No. EPA-OAR-2002-0049-0061.

                  Table 3--Combined 2005 and 2010 lb/ton EAF Datasets With 2005 EAF A/C Ratios
----------------------------------------------------------------------------------------------------------------
                                                                                2005 facility A/C
                Count                 2010 Zero opacity facilities        2010 lb/ton        (weighted average)
----------------------------------------------------------------------------------------------------------------
1...................................  Timken-Faircrest-OH.........  1.3E-02...............                   3.4
2...................................  Nucor-Crawfordsville-IN.....  1.6E-02...............                   3.2
3...................................  Gerdau-Charlotte-NC.........  2.3E-02...............                   2.2
4...................................  Timken-Harrison-OH..........  3.6E-02...............                   2.6
5...................................  Nucor-Huger-SC..............  5.2E-02...............                   2.6
6...................................  CMC-Birmingham-AL...........  5.5E-02...............                   3.7
7...................................  CMC-Cayce-SC................  6.4E-02...............                   3.3
8...................................  NAS-Ghent-KY................  1.6E-01...............            4.5 (2010)
----------------------------------------------------------------------------------------------------------------
Count                                   2005 Facilities with P/S          2005 lb/ton         2005 Facility A/C
                                                Baghouses                                     (weighted average)
----------------------------------------------------------------------------------------------------------------
1...................................  Nucor-Norfolk-NE............  8.7E-03...............                   2.8
2...................................  Nucor-Cofield-NC............  1.3E-02...............                   3.0
3...................................  Nucor-Blytheville-AR........  1.4E-02...............                   3.0
4...................................  Nucor Bar Mill-Plymouth-UT..  1.8E-02...............                   2.1
5...................................  North Star Steel-St. Paul-MN  1.9E-02...............                   2.0
6...................................  Nucor Berkeley-Huger-SC.....  2.2E-02...............                   2.6
7...................................  IPSCO Steel-Axis-AL.........  3.2E-02...............                   2.6
8...................................  SMI Steel-Cayce-SC..........  5.8E-02...............                   3.3
9...................................  CMC/Struct Metals/SMI-Sequin- 8.5E-02...............                   6.0
                                       TX.
10..................................  IPSCO Steel-Muscatine-IA....  8.7E-02...............                   5.1
----------------------------------------------------------------------------------------------------------------

 Table 4--Comparison of BSER Model Plants for Small, Medium, and Large EAF Facilities Using Two Datasets: 2005 EAF A/C Ratios and 2010 II&S A/C Ratios,
                                                             Both With 2010 EAF lb/ton Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                         Total       EAF facility            A/C ratio (ft/min)                Cost for new baghouse        Incremental
                                    controlled EAF      average    ----------------------------------------------------------------------      cost
                                     PM emissions     production                                                                           effectiveness
                                   --------------------------------                                                                         compared to
          Model plant \a\                                                                                next lower-
                                                                         Value              Basis            Capital $    Annual costs $/ emitting model
                                        lb/ton            tpy                                                                   yr           plant \b\
                                                                                ---------------
                                                                                delta$/ton PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Small Facility
--------------------------------------------------------------------------------------------------------------------------------------------------------
E.................................            0.16          50,000             7.2  2011 II&S...........        $796,912        $341,981         $13,340
F.................................            0.16          50,000             8.0  2005 EAF............         767,439         338,610           7,196
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Medium Facility
--------------------------------------------------------------------------------------------------------------------------------------------------------
E.................................            0.16         775,000             7.2  2011 II&S...........       4,778,920       2,045,443          12,197
F.................................            0.16         775,000             8.0  2005 EAF............       4,361,224       1,997,701           6,575
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Large Facility
--------------------------------------------------------------------------------------------------------------------------------------------------------
E.................................            0.16       3,450,000             7.2  2011 II&S...........      21,929,003       8,598,613          13,708
F.................................            0.16       3,450,000             8.0  2005 EAF............      19,839,154       8,359,718           7,390
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Model Plants E and F are both the highest emitting model plants in the two datasets, where the A/C data for Model E is from II&S A/C data and for
  Model F the 2005 CAA section 114 responses are used for A/C data. Cost analysis values for Model E are the same as from proposal, with updates to
  reflect $2022 for the final rule v. $2020 that were used for the proposed rule.
\b\ The incremental cost effectiveness from Model Plant E to D in $2022, at $12,200/ton for medium-sized facility, is higher than the same comparison of
  the same model plants in $2020, at $8,500/ton, because of the increase in the values used in the cost estimate as a result of inflation and increase
  in interest rate from 3.5 percent to 7.5 percent from 2020 to 2022.

    Comment: The commenter asserted that the change from a
concentration to lb/ton limit complicates compliance and does not
result in better control or greater assurance of compliance. The
commenter stated the EPA's assertion that switching to a lb/ton
standard will ``result in better control and greater assurance of
compliance'' is incorrect. Under the current standards in NSPS subparts
AA and AAa, compliance is readily demonstrated through EPA Method 5
monitoring of the stack on the primary control device/baghouse. This is
a direct measurement of the filtering ability of the baghouse and
evidence of compliance with concentration limits without all of the
unnecessary variables the new rule introduces which are not directly
related to emissions. Under the proposal, facilities subject to NSPS
subpart AAb would be required to track tonnages produced during stack
tests and match those to emissions data.
    EPA Response: The commenter is correct that with a lb/ton standard,
facilities subject to NSPS subpart AAb will be required to track
tonnages produced during stack tests and match those to emissions data.
However, this is already required in the current EAF NSPS (compare 40
CFR 60.274(i)(1), 60.274a(h)(1) with proposed and final 40 CFR
60.274b(h)(1)). The 31 facilities in the 2010 EPA/EAF data set were
able to report steel produced during the testing. Therefore, we expect
the entire industry to be able to do so.
    The baghouse PM emission data in gr/dscf do not address the total
emissions generated by a facility. The gr/dscf data can be influenced
by increasing dilution air to the baghouse and is not directly related
to steel production as PM emissions logically should be. Using
concentration in gr/dscf to assess the filtering ability of baghouses
can still be done at any time but it doesn't necessarily reflect the
contribution of PM by the facility's steel production to the
environment. In order to assess a facility's impact to the local
environment, the general public would need to know the exhaust rates of
every baghouse at a facility to determine the facility's PM emissions,
whereas from lb/ton facility-wide data, the maximum amount of PM being
emitted can be easily ascertained with only one steel production value
and one facility-wide PM limit.
    Comment: The commenter asserted that the lb/ton limit does not
consider vendor guarantees on control systems. The commenter stated it
is critical to obtain vendor guarantees from suppliers when
constructing new facilities or EAF and associated control systems, to
ensure that the purchased equipment can comply with applicable
standards. Vendors can guarantee that the filters/control device have a
specific removal rate (i.e., vendors can only guarantee the difference
between the clean and dirty side of the bag). Obtaining such guarantees
is what gives facilities comfort that the equipment they purchase will
perform such that compliance is assured. The commenter stated that such
comfort is not possible with the Agency's proposed ``facility-wide'' PM
limit, because vendors do not offer lb/ton guarantees for specific
equipment and certainly not on a facility-wide basis. This is
understandable given a supplier's ability to design equipment to a
given concentration or control specification, but lack of ability to
control the many factors that influence lb/ton efficiency, especially
where a vendor may not be the sole facility-wide designer. Vendors have
no control over the tonnage of steel produced or how the steel tonnage
estimate comports with the duration of the PM measurement. The
commenter concluded the EPA should take this into account by setting a
concentration-based emission standard and noted that the EPA has
previously acknowledged the importance of being able to obtain vendor
guarantees when setting the NSPS subpart AAa limits in 1984 (49 FR
43840). The commenter stated that it would thus be arbitrary and
impermissible for the EPA to ignore that consideration here.
    EPA Response: Vendors can continue to use gr/dscf to assess the
filtering ability of a baghouse, especially since the NESHAP for EAF
(40 CFR part 63, subpart YYYYY) still requires gr/dscf determinations.
In addition, the calculation of PM concentration in gr PM/dscf is an
intermediate step in the calculation of lb PM/ton steel emission rate:
concentration (gr/dscf) * flow rate (dscf) = emission rate, as PM in
lb/hr; then divide by tons per hour steel for lb PM/ton steel format.
Moreover, evaluating the impact of a new facility (or reconstructed or
modified facility) under the NSPS subpart AAb, in terms of PM emissions
on the surrounding communities, is more easily determined from a lb/ton
limit and overall facility steel production. With a lb/ton limit, not
only must a new facility determine that their baghouses are working
properly, but they must also determine whether the facility is being
efficient in its generation of PM at the desired production level
compared to the best facilities operating at the same production level.
    Comment: A commenter noted that EAF National Emission Standards for
Hazardous Air Pollutants (NESHAP) 40 CFR part 63 subpart YYYYY requires
concentration limits. The commenter stated the maximum achievable
control technology (MACT) standard in the NESHAP for EAF (40 CFR part
63, subpart YYYYY) independently limits PM emissions from each EAF to
0.0052 gr/dscf. The proposed NSPS would thus have the result of
subjecting facilities to both a lb/ton limit (via NSPS) and a
concentration limit (via NESHAP). Since facilities will still have to
track gr/dscf anyway to comply with NESHAP limits, it would be
inefficient and unreasonable to also require a lb/ton limit.
    EPA Response: The applicability between the NSPS and NESHAP are
different. All existing EAF facilities will continue to meet the gr/
dscf PM limit in the NESHAP. Only new, reconstructed, or modified EAF
or AOD units and their control devices need to meet both the lb/ton PM
total facility limit that is being finalized in NSPS subpart AAb along
with the NESHAP's individual baghouse limit. As discussed in previous
responses to comments in this section, the data needed to show
compliance with both standards are obtained in the same test. The
combination of the two standards results in the public and regulators
being able to more accurately evaluate EAF operation and the potential
impact of new facilities on surrounding communities because the rules
together limit total facility PM emissions impacts while checking
individual control device operation. Facilities subject to the NSPS
subpart AAb, and their vendors can continue use the gr/dscf limit to
troubleshoot baghouse operation just as facilities have done in the
past.
    For facilities that modify or reconstruct after May 16, 2022, only
the EAF(s) or AOD(s) and the air pollution control equipment that were
modified or reconstructed after May 16, 2022, must comply with NSPS
subpart AAb. This provision has been added to the rule at in 40 CFR
60.271b under the definition of ``Electric arc furnace facility.'' If
there are capture systems and control devices that capture PM emissions
from sources subject to NSPS subparts AA or AAa at the same site where
there are also sources subject to NSPS subpart AAb, the procedures
described in the rule at 40 CFR 60.275b(b) include any one of the
following options (see also 40 CFR 60.276bI) to determine compliance:
use the combined emissions; use a method that is acceptable to the
Administrator or delegated authority and that compensates for the
emissions from the facilities not subject to the provisions of

this subpart; or any combination of the above methods.
3. What is the rationale for the final BSER determination and what is
the final standard of performance?
    The EPA is finalizing the proposed determination that the BSER for
EAF and AOD is capture and control of PM with a fabric filer. The EPA
is further finalizing the proposed determination that limit based on
the BSER at 0.16 lb/ton total facility PM is achievable for any new,
modified, or reconstructed facility because it is based on the EPA's
data from approximately one third of the industry. The format of the
limit based on BSER (total facility lb PM/ton steel produced from all
affected capture systems and fabric filters) provides complete
information on the performance of the facility and their EAF rather
than that of just the individual baghouse(s) and individual EAF via a
concentration based standard, and enables the public and regulators to
know the total pollutant impact of the facility's EAF operation on the
surrounding community. The current concentration-based limit in NSPS
subparts AA and AAa is influenced by the amount of dilution air in the
exhaust going through the baghouse, which can be adjusted to some
extent by the facility without significant detriment to baghouse
operation. Evaluating the impact of PM emissions from a new EAF
facility (or reconstructed or modified facility) on the surrounding
communities is more easily determined from a facility-wide lb/ton
limit. With a lb/ton limit, not only must a new facility determine that
their baghouses are working properly, but they must also determine
whether the facility is being efficient in its generation of PM at the
desired production level compared to the best facilities operating at
the same production level. In addition, the total facility lb/ton PM
limit provides an overall assessment of emissions from the facility in
a format that scales emissions to production, which is based on
fundamental engineering principles. The current concentration-based
limits in NSPS subparts AA and AAa do not limit the air flow or the
number of baghouses that could be used to comply with the standard.
    Based on data from 31 EAF facilities (more than one third of the
industry), all 31 facilities' baghouse emissions are 40 percent or
lower than the current concentration-based limit in 40 CFR part 60,
subparts AA, AAa. Therefore, the 0.16 lb/ton production-based limit
based on these same data is a significant improvement in emissions
control compared to the current standard. Moreover, because the lb/ton
limit is the highest level in the EPA data set that includes one third
of the industry, the standard that the EPA has determined to reflect
the application of the BSER technology is achievable.
    Lastly, we used both 2005 EAF PM data with EAF 2005 A/C data, and
2010 EAF PM data with 2005 EAF A/C data for the cost analysis to
determine BSER for the EAF lb/ton PM standard, and reached the same
conclusion as we did for proposal with 2010 EAF PM data and 2010 II&S
A/C data. Therefore, in this final rule, the use of a capture system
and fabric filter was determined as the BSER. The PM limit based on
BSER of 0.16 lb PM/ton steel facility-wide was derived from the data
available to the EPA, which comprised approximately one third of the
industry, and also where the EPA considered costs, nonair quality
health and environmental impacts, and energy requirements (described
below in sections V.A and V.B).
4. Are there any relevant energy impacts or nonair quality health and
environmental impacts of the selection of the final BSER and, if so,
how were the final emission limitations based on BSER affected?
    The EPA did not identify any relevant energy impacts or nonair
quality health and environmental impacts of the proposed or final
standards for PM emissions from EAF and AOD control devices
(baghouses). See sections V.A and V.B. of this preamble for details. No
comments were received on these issues.

B. NSPS Requirements for Opacity From Melt Shops for Electric Arc
Furnaces and Argon-Oxygen Decarburization Vessels Constructed After May
16, 2022

1. What did we propose as the BSER determination and standard of
performance?
    We proposed that VE from EAF and AOD that exit from the melt shop
would be limited to an opacity of 0 percent during all phases of
operation, based on the determination of BSER as the addition of a
partial roof canopy to capture and control melt shop fugitive
emissions.
2. What significant comments did we receive and what are our responses?
    Comment: One commenter asserted that the proposed 0 percent melt
shop opacity limit disregards workers' safety by requiring the closure
of roof and buildings. Specifically, the commenter stated the proposed
0 percent melt shop opacity limit disregarded workers' safety related
to heat stress and material handling activities and that, therefore,
the EPA should reconsider the 0 percent opacity limit. The commenter
stated the proposal did not include an analysis of impacts for closure
of building openings. A review of the impacts on worker heat stress
would be necessary and that the EPA had provided no justification for
requiring melt shops to close all openings.
    The commenter noted the current proposed rule did not address heat
stress concerns, which was in conflict with OSHA's current Heat Stress
Initiative and National Enforcement Program that identified ``iron and
steel mills'' specifically as a high hazard industry for heat stress.
The commenter stated that safe melt shop operation requires air flow to
minimize potential heat stress on workers and equipment. The commenter
claimed that negative pressure alone was not sufficient to maintain
proper airflow through the melt shop and that cross drafts were
necessary and doors and other access points needed to be open. The
commenter also had significant concerns about employee health impacts
from the proposed totally enclosed melt shop, particularly for its
Mobile, Alabama facility, which is located in an extreme climate area,
as the proposed changes could cause greater heat stress on employees
and would necessitate design and structural changes that the EPA failed
to consider in its proposal. The commenter stated that 100 percent
capture and 0 percent opacity may not be safe. The commenter noted when
evaluating 2 different control systems, the EPA may not simply choose
the most cost-effective air pollution control system if it potentially
has adverse impacts on the health and safety of workers within the melt
shop. The commenter stated that facilities need to allow air changes to
protect worker health and safety.
    The commenter referenced the 1984 amendments, which dismissed the
option for a closed roof configuration to achieve 0 percent opacity due
to the impacts of heat stress on worker safety and equipment
functioning. A commenter said that statements made by the EPA in the
1984 40 CFR part 60, subpart AAa rulemaking (49 FR 43841) that ``the
visible emission limits were selected-based on the performance of the
capture and control technologies that served as the basis for
Regulatory Alternative B (partially open roof monitor)'' and that
``Regulatory Alternative C (closed roof) was not considered suitable as
the basis for national standards of performance because it is based on
a closed roof

configuration which may aggravate worker and equipment heat stress
problems.''
    EPA Response: The proposed rule 40 CFR part 60, subpart AAb did not
require a closed roof nor a totally enclosed melt shop. In addition,
the 0 percent shop opacity limit does not restrict air flow from
exiting or entering the shop. Rather, the 0 percent opacity limit
merely necessitates that no visible particles be emitted from the shop
(as reflected by either no VE observations via EPA Method 22 or opacity
of 0 percent using EPA Method 9 or the DCOT method). Canopy hoods have
the benefit of being able to collect a large volume of emissions,
especially those during charging and tapping and route the PM to
control devices. Therefore, the basis for the addition of a partial
roof canopy with a canopy hood used in the proposed and final cost
estimates is to ensure facilities clean the air of particles before
allowing the air to exit the shop opening(s). We believe a capture
device such as a canopy hood, as opposed to a closed roof, can be used
to meet the opacity limit based on BSER and does not endanger worker
safety.
    Comment: The commenter asserted that the EPA used a limited data
set that was not indicative of continuous long-term performance and did
not support a finding that 0 percent opacity was adequately
demonstrated. The commenter stated the EPA's dataset for EAF steel
mills is selective and not representative of the full scope of
operations at these facilities. The commenter stated that the EPA
purported to have based the proposed 40 CFR part 60, subpart AAb shop
opacity limit on individual performance testing reports from a total of
13 of 31 EAF steel mills, which was less than half. The commenter noted
that most facilities (16 out of 31) were unable to maintain 0 percent
shop opacity throughout the duration of the performance tests. Thus, as
the majority of facilities in the EPA's database did not maintain 0
percent opacity, the short duration of performance testing plainly
demonstrated that 0 percent shop opacity was not adequately
demonstrated.
    Another commenter stated the EPA's proposal of 0 percent opacity
from the melt shop was based on limited information from opacity tests
conducted at 31 facilities, of which less than half achieved the 0
percent melt shop opacity requirement. The commenter stated that the
short-term observations conducted during a stack test were taken for a
few hours under a specific set of conditions and were not
representative of long-term compliance capability and, as such, could
not account for routine operating variability and the full range of
operating conditions that may affect opacity. The commenter stated that
the subset of data the EPA relied upon did not include longer-term
operating performance of the identified mills; yet NSPS, as defined by
BSER, must account for what was achievable and adequately demonstrated
by a wide variety of facilities operating under a wide variety of
conditions, not simply show that the standard was achieved at a model
plant for a short period of time. The commenter also noted that the
data collected by the EPA generally showed that the more years of
opacity data reviewed for a given facility, the higher the maximum melt
shop opacity.
    EPA Response: Thirteen facilities out of the 31 EAF facilities in
the EPA data set had 0.00 percent shop opacity during the tests which
were reported to the EPA. Two additional facilities in the EPA data set
achieved 0.00 percent shop opacity as shown in the submitted test
reports and another 4 facilities achieved 0.0 percent as shown in the
submitted test reports, for a total of 19 facilities appearing to
already be complying with a 0 percent shop standard (1 significant
figure) based on tests in the submitted reports, and which were
performed using the same test method that would be required to show
compliance with the NSPS. Out of the total 31 facilities in the EPA EAF
data, only 1 facility had shop opacity greater than 1 percent as an
average of all runs in the test, with the overall average among the 31
facilities in the EPA data set at 0.14 percent opacity. See the list of
31 EAF facilities and the opacity test results from reports submitted
to the EPA in the 2010 EPA/EAF data set, as shown in Table 5. None of
the opacity data submitted to the EPA in 2010 should be construed as
being from a ``model plant.'' The opacity data was taken from
facilities responding to the CAA section 114 information request with
the primary purposes to obtain mercury emissions data and were real
facilities, comprising a third of the industry. Data for PM and opacity
were collected as part of the CAA section 114 information request only
for purposes of showing that the reported mercury data were taken
during the time the facility was complying with both the NESHAP (40 CFR
part 63, subpart YYYYY) and NSPS (40 CFR part 60, subparts AA and AAa).

 Table 5--Range of Melt Shop Opacity in 31 EAF Test Reports (2005-2011)
                  From the 2010 CAA Section 114 Request
                         [2010 EPA/EAF Data Set]
------------------------------------------------------------------------
                                                       Melt shop opacity
             Count                   Facility ID           (percent)
------------------------------------------------------------------------
1.............................  AKS-Butler-PA........              0.000
2.............................  AKS-Mansfield-OH.....              0.000
3.............................  CMC-Birmingham-AL....              0.000
4.............................  CMC-Cayce-SC.........              0.000
5.............................  CMC-Mesa-AZ..........              0.000
6.............................  Ger-Charlotte-NC.....              0.000
7.............................  Ger-Jackson-MI.......              0.000
8.............................  NAS-Ghent-KY.........              0.000
9.............................  Nuc-Crawfordsville-IN              0.000
10............................  Nuc-Huger-SC.........              0.000
11............................  Nuc-Jewett-TX........              0.000
12............................  Nuc-Marion-OH........              0.000
13............................  SSAB-Axis-AL.........              0.000
14............................  Tim-Faircrest-OH.....              0.000
15............................  Tim-Harrison-OH......              0.000
16............................  Nuc-Darlington-SC....              0.001
17............................  Ger-Knoxville-TN.....               0.01
18............................  Ger-StPaul-MN........               0.02

19............................  Nuc-Plymouth-UT......               0.05
20............................  CMC-Seguin-TX........               0.10
21............................  Ger-Wilton-IA........               0.10
22............................  Ger-Jacksonville-FL..               0.10
23............................  Ger-Jackson-TN.......               0.20
24............................  Alle-Brackenridge-PA.               0.20
25............................  Nuc-Cofield-NC.......               0.20
26............................  Alle-Latrobe-PA......               0.30
27............................  Nuc-Blytheville-AR...               0.30
28............................  Nuc-Norfolk-NE.......               0.30
29............................  Ger-Beaumont-TX......               0.50
30............................  Ger-Cartersville-GA..               0.80
31............................  Ster-Sterling-IL.....                1.2
                                Overall average......               0.14
------------------------------------------------------------------------

    It would be exorbitantly expensive to the industry (as well as the
EPA) for the EPA to request and analyze round-the-clock opacity testing
throughout the course of years at a number of facilities in order to
obtain data during a ``wide variety of conditions and wide variety of
facilities.'' None of the opacity requirements in previously
promulgated rules (40 CFR part 60, subparts AA and AAa) have
differentiated conditions or facility types for the opacity
requirements in those rules. The commenter does not provide any
information showing that the need for these data is justified, except
for alluding to the fact that facilities improved their control of
opacity in more recent years.
    The goal of determining BSER is that it is the ``best'' system of
emission reduction (considering costs and other factors), not the
system used by the majority of the industry nor the top facilities when
ranked or any other ranking method. However, the EPA acknowledges that
the data obtained through CAA section 114 requests consisted of data
collected during melting and refining, which is the time period
required to test opacity in the current EAF NSPS rules in 40 CFR part
60, subparts AA, AAa. Therefore, in light of comments provided by the
industry that reducing opacity during charging and tapping is difficult
to achieve because of the physical structure of equipment and because
of the much higher PM emissions during charging and tapping than during
melting and refining, in the final rule for 40 FCR part 60, subpart AAb
we are maintaining the current rule limit in 40 CFR part 60, subparts
AA, AAa of 6 percent opacity to apply during charging and tapping, and
retaining the proposed 0 percent melt shop opacity for melting and
refining. We estimate that the period of charging and tapping is
approximately 15 percent of the total EAF operating time period.
    Comment: The commenter asserted that the EPA's limited data set is
not representative of performance during ``charging and tapping''; 0
percent opacity should not apply to charging and tapping. The commenter
stated the EPA's opacity data set did not adequately demonstrate that a
0 percent opacity limit could be consistently achievable across the
full spectrum of expected operating conditions. The commenter said the
vast majority of the opacity measurements in the data set were based on
measurements taken during the melting and refining stage of production
(as required under 40 CFR part 60, subpart AAa), and thus did not
demonstrate that 0 percent opacity had been consistently achieved
during charging or tapping, which was the established period with the
greatest potential for uncaptured emissions to escape the melt shop.
The commenter noted that most EAF steel mills were designed such that
the primary emission controls (DEC) could not be engaged while the
furnace roof was off during charging and tapping.
    A commenter referenced previous rulemaking to corroborate their
statements that the EPA did not consider its own historical
information. One commenter referred to background documents for earlier
NSPS rulings stating that in those documents, the EPA concluded that
facilities utilizing DEC were likely to have a visible plume during
charging and tapping and could not meet 0 percent opacity on a
continuous basis. One commenter referenced the 1983 rulemaking docket
stating it included only 7 hours of shop opacity data from some portion
of the charging and tapping phase, and that such limited data from 4
decades ago was not representative of, or sufficient to, characterize
current melt shop operations. The commenter said these previous
findings by the EPA contradict the current proposal that 0 percent
opacity was achievable on a continuous basis.
    A commenter provided confidential summaries of long-term shop
opacity data from the 13 facilities identified by the EPA as achieving
the 0 percent standard, and noted that most of the opacity data was
collected only during melting and refining, and not during charging and
tapping. The commenter stated their summaries demonstrated that 0
percent melt shop opacity was not continuously achieved by the 13 mills
cited as exemplars. The commenter noted in a reference that they would
readily provide the confidential data to the EPA upon request.
    A commenter stated that the current design at their facilities
included DEC and a baghouse with a canopy, which under the proposed
rule was considered the optimal design, yet it appeared the EPA did not
include opacity data from their facilities in the limited data set. The
commenter noted they fully complied with current limits in 40 CFR part
60, subparts AA, AAa, including opacity; but their facility data showed
that compliance with a 0 percent opacity limit at all times per the
proposed standard could not be met continuously due to the production
process variability and the raw material inputs. The commenter stated
it was possible for the melt shop to experience an opacity greater than
0 percent during charging and tapping when the DEC

system was disengaged, and there were other sources of opacity from
concurrent operations (e.g., vacuum tank degasser operations, the LMF,
and the Caster).
    A commenter said the EPA in the proposed rule stated 0 percent
opacity could be achieved utilizing a canopy over the furnace with an
open roof monitor elsewhere. The commenter operated its facilities
under such a configuration and did not meet 0 percent opacity on a
continuous basis; thus, the EPA's data set was flawed and not
representative of the steel manufacturing operation.
    EPA Response: The EPA reviewed the summary data provided by the
commenter, where for three facilities, the opacity summary data shown
in Table 6 were provided.

                               Table 6--SMA Data on Opacity From Three Facilities
----------------------------------------------------------------------------------------------------------------
                                                      Number
                                                    readings >0    Total number     Percent >0
                SMA facility No.                      percent         opacity     percent out of   Year of data
                                                      opacity        readings      all readings
----------------------------------------------------------------------------------------------------------------
1...............................................               3             349             0.9            2021
                                                               0             296            None            2020
                                                              11             294             3.7            2019
2...............................................              21           1,482             1.4       2021-2022
3...............................................              61           2,488             2.5       2021-2022
----------------------------------------------------------------------------------------------------------------

    Although the commenter presented these data attempting to
contradict 0 percent opacity as BSER, the data actually support the
preponderance of opacity data at 0 percent, since the number of
readings greater than 0 percent were low, ranging from none (i.e., no
readings greater than 0 percent) to a high of 3.7 percent, out of a
total number of readings ranging from 300 to 2,500.
    The EPA's evaluation of the degree of emission limitation
achievable with the BSER is not based on an average of all facility
data nor an average of the best facilities. Rather, the BSER is the
best system of control that the EPA determines is adequately
demonstrated for EAF in the industry, and the EPA's charge under CAA
111(a)(1) and (b)(1)(B) is to establish a standard of performance that
reflects the degree of emission limitation achievable by application of
that BSER.
    The EPA EAF data, taken mostly from the 2010 CAA section 114
request, required ``an aggregate total of 180 minutes of opacity