[Federal Register Volume 88, Number 145 (Monday, July 31, 2023)]
[Proposed Rules]
[Pages 49402-49423]
[FR Doc No: 2023-15085]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0083; FRL-5919.1-01-OAR]
RIN 2060-AV82

National Emission Standards for Hazardous Air Pollutants:
Integrated Iron and Steel Manufacturing Facilities Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing
amendments to the National Emission Standards for Hazardous Air
Pollutants (NESHAP) for Integrated Iron and Steel Manufacturing
Facilities, as required by the Clean Air Act (CAA). To complete the
required CAA section 112(d)(6) technology review promulgated on July
13, 2020, the EPA is proposing standards to regulate HAP emissions from
five unmeasured fugitive and intermittent particulate (UFIP) sources,
some of which are also referred to as ``fugitive'' sources, that are
currently not regulated by the NESHAP, as follows: Bell Leaks,
Unplanned Bleeder Valve Openings, Planned Bleeder Valve Openings, Slag
Pits, and Beaching. Also, for sinter plants we are proposing standards
for the following five currently unregulated HAP: carbonyl sulfide
(COS), carbon disulfide (CS2), mercury (Hg), hydrochloric
acid (HCl), and hydrogen fluoride (HF); for blast furnace (BF) stoves
and basic oxygen process furnaces (BOPFs), we are proposing standards
for the following three unregulated pollutants: total hydrocarbons
(THC), HCl, and dioxins/furans (D/F); and for BFs, we are proposing
standards for the following two unregulated pollutants: THC and HCl. As
an update to the technology review, we are proposing to revise the
current BOPF shop fugitive 20 percent opacity limit to a 5 percent
opacity limit and require specific work practices; revise the current
BF casthouse fugitive 20 percent opacity limit to a 5 percent opacity
limit; and revise the current standards for D/F and polycyclic
hydrocarbon (PAH) for sinter plants. We are also proposing a fenceline
monitoring requirement for chromium (Cr), including a requirement that
if a monitor exceeds the proposed Cr action level, the facility will
need to conduct a root cause analysis and take corrective action to
lower emissions. We solicit comments on all aspects of this proposed
action.

DATES: Comments. Comments must be received on or before September 14,
2023. Under the Paperwork Reduction Act (PRA), comments on the
information collection provisions are best assured of consideration if
the Office of Management and Budget (OMB) receives a copy of your
comments on or before August 30, 2023.
    Public hearing: If anyone contacts us requesting a public hearing
on or before August 7, 2023 by 5:00 p.m. Eastern Time (ET), we will
hold a virtual public hearing. See SUPPLEMENTARY INFORMATION for
information on requesting and registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2002-0083, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2002-0083 in the subject line of the message.
     Fax:<PHONE_NUMBER>. Attention Docket ID No. EPA-HQ-OAR-
2002-0083.
     Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket ID No. EPA-HQ-OAR-2002-0083, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal holidays).
    Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov/, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed
action, contact Phil Mulrine, Sector Policies and Programs Division
(D243-02), 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:

    Participation in virtual public hearing.
    To request a virtual public hearing, contact the public hearing
team at<PHONE_NUMBER> or by email at [email protected]. If
requested, the hearing will be held via virtual platform on August 15,
2023. The hearing will convene at 10:00 a.m. ET and will conclude at
4:00 p.m. ET. The EPA may close a session 15 minutes after the last
pre-registered speaker has testified if there are no additional
speakers. The EPA will announce further details at https://www.epa.gov/stationary-sources-air-pollution/integrated-iron-and-steel-manufacturing-national-emission.
    If a public hearing is requested, the EPA will begin pre-
registering speakers for the hearing no later than 1 business day after
a request has been received. To register to speak at the virtual
hearing, please use the online registration form available at https://www.epa.gov/stationary-sources-air-pollution/integrated-iron-and-steel-manufacturing-national-emission or contact the public hearing team at
(888) 372-8699 or by email at [email protected]. The last day
to pre-register to speak at the hearing will be August 14, 2023. Prior
to the hearing, the EPA will post a general agenda that will list pre-
registered speakers in approximate order at: https://www.epa.gov/stationary-sources-air-pollution/integrated-iron-and-steel-manufacturing-national-emission.
    The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 4 minutes to provide oral testimony. The
EPA encourages commenters to provide the EPA with a copy of their oral
testimony electronically (via email) by emailing it to
[email protected]. The EPA also recommends submitting the text of
your oral testimony as written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations
but will not respond to the presentations at that time. Written
statements and supporting information submitted during the comment
period will be considered with the same weight as oral testimony and
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will
be posted online at https://www.epa.gov/stationary-sources-air-pollution/integrated-iron-and-steel-manufacturing-national-emission.
While the EPA expects the hearing to go forward as set forth above,
please monitor our website or contact the public hearing team at (888)
372-8699 or by email at [email protected] to determine if there
are any updates. The EPA does not intend to publish a document in the
Federal Register announcing updates.
    If you require the services of a translator or a special
accommodation such as audio description, please pre-register for the
hearing with the public hearing team and describe your needs by August
7, 2023. The EPA may not be able to arrange accommodations without
advanced notice.
    Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2002-0083. All documents in the docket are
listed in https://www.regulations.gov/. Although listed, some
information is not publicly available, e.g., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the internet and will be publicly available only in hard
copy. With the exception of such material, publicly available docket
materials are available electronically in Regulations.gov.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2002-0083. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at https://www.regulations.gov/, including any personal
information provided, unless the comment includes information claimed
to be CBI or other information whose disclosure is restricted by
statute. Do not submit electronically to https://www.regulations.gov
any information that you consider to be CBI or other information whose
disclosure is restricted by statute. This type of information should be
submitted as discussed below.
    The EPA may publish any comment received to its public docket.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the Web, cloud, or other
file sharing system). For additional submission methods, the full EPA
public comment policy, information about CBI or multimedia submissions,
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your
comment anonymously, which means the EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send an email comment directly to the EPA without going through
https://www.regulations.gov/, your email address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the internet. If you submit an
electronic comment, the EPA recommends that you include your name and
other contact information in the body of your comment and with any
digital storage media you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should not include special characters or any form of encryption and be
free of any defects or viruses. For additional information about the
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA
through https://www.regulations.gov/. Clearly mark the part or all of
the information that you claim to be CBI. For CBI information on any
digital storage media that you mail to the EPA, note the docket ID,
mark the outside of the digital storage media as CBI and identify
electronically within the digital storage media the specific
information that is claimed as CBI. In addition to one complete version
of the comments that includes information claimed as CBI, you must
submit a copy of the comments that does not contain the information
claimed as CBI directly to the public docket through the procedures
outlined in the Instructions section of this document. If you submit
any digital storage media that does not contain CBI, mark the outside
of the digital storage media clearly that it does not contain CBI and
note the docket ID. Information not marked as CBI will be included in
the public docket and the EPA's electronic public docket without prior
notice. Information marked as CBI will not be disclosed except in
accordance with procedures set forth in 40 CFR (Code of Federal
Regulations) part 2.
    Our preferred method to receive CBI is for it to be transmitted
electronically using email attachments, File Transfer Protocol (FTP),
or other online file sharing services (e.g., Dropbox, OneDrive, Google
Drive). Electronic

submissions must be transmitted directly to the OAQPS CBI Office at the
email address [email protected], and as described above, should include
clear CBI markings and note the docket ID. If assistance is needed with
submitting large electronic files that exceed the file size limit for
email attachments, and if you do not have your own file sharing
service, please email [email protected] to request a file transfer link.
If sending CBI information through the postal service, please send it
to the following address: OAQPS Document Control Officer (C404-02),
OAQPS, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2002-0083. The
mailed CBI material should be double wrapped and clearly marked. Any
CBI markings should not show through the outer envelope.
    Preamble acronyms and abbreviations. Throughout this preamble the
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. We
use multiple acronyms and terms in this preamble. While this list may
not be exhaustive, to ease the reading of this preamble and for
reference purposes, the EPA defines the following terms and acronyms
here:

1-BP 1-bromopropane
ACI activated carbon injection
BF blast furnace
BOPF basic oxygen process furnace
BTF Beyond-the-Floor
CAA Clean Air Act
CBI Confidential Business Information
COS Carbonyl Sulfide
CFR Code of Federal Regulations
D/F dioxins and furans
EAV equivalent annualized value
EJ environmental justice
EPA Environmental Protection Agency
FR Federal Register
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HF hydrogen fluoride
HMTDS hot metal transfer, desulfurization, and skimming
ICR Information Collection Request
km kilometer
MACT maximum achievable control technology
NESHAP national emission standards for hazardous air pollutants
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PAH polycyclic aromatic hydrocarbons
PM particulate matter
PRA Paperwork Reduction Act
PV present value
RFA Regulatory Flexibility Act
RTR residual risk and technology review
THC total hydrocarbon
TEQ toxic equivalents
tpy tons per year
UFIP unmeasured fugitive and intermittent particulate
UMRA Unfunded Mandates Reform Act
UPL upper prediction limit
VCS voluntary consensus standards
VE visible emissions
VOC volatile organic compound
WP work practice

    Organization of this document. The information in this preamble is
organized as follows below. Section III of this preamble presents a
summary of the analytical procedures and decision-making process.
Section IV of this preamble describes the majority of the Agency's
analytical results, proposed decisions and the rationale for the
actions proposed in this action. Other sections include discussion of
costs and impacts and the applicable executive orders, and other
relevant topics, as outlined in the following table of contents.

Table of Contents

I. General Information
    A. Executive Summary
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP
regulate its HAP emissions?
    C. What data collection activities were conducted to support
this action?
    D. What other relevant background information and data are
available?
III. Analytical Procedures and Decision-Making
    A. How do we perform the technology review?
    B. How do we develop and calculate CAA section 112(d)(2) and (3)
standards?
IV. Analytical Results and Proposed Decisions
    A. Proposed Standards To Address Five Unregulated UFIP Sources
for Both New and Existing Sources
    B. Reconsideration of BF Casthouse and BOPF Shop Standards for
Currently Regulated Fugitive Sources Under CAA 112(D)(6) Technology
Review for Both New and Existing Sources
    C. Results of Fenceline Monitoring Data Analyses
    D. What are the proposed decisions based on our fenceline
monitoring data analysis, and what is the rationale for those
decisions?
    E. Proposed Standards To Address Unregulated Point Sources for
Both New And Existing Sources
    F. Reconsideration of Standards for D/F and PAH for Sinter
Plants Under CAA Section 112 (D)(6) Technology Review for Both New
and Existing Sources
    G. Adding 1-Bromopropane to List of HAP
    H. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality 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. Request for Comments
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and 13563
Improving Regulation and 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

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    The EPA set maximum achievable control technology (MACT) standards
for the Integrated Iron and Steel Manufacturing Facilities major source
category in 2003 (68 FR 27645) under 40 CFR part 63, subpart FFFFF and
completed a residual risk and technology review final rule in July 2020
(85 FR 42074). The purpose of this proposed rule is to (1) fulfill the
EPA's statutory obligations pursuant to CAA section 112(d)(6) and the
U.S. Court of Appeals for the D.C. Circuit's interpretation of that
statute in Louisiana Environmental Action Network v. EPA, 955 F.3d 1088
(D.C. Cir. 2020) (``LEAN''), and (2) improve the emissions standards
for this source category based on new information regarding
developments in practices, processes and control technologies.
2. Summary of the Major Provisions of the Regulatory Action
    To comply with CAA section 112, we are proposing (1) new emissions
limits based on MACT for five currently unregulated HAP (COS,
CS2, Hg, HCl, and HF) from the sinter plants located at
integrated iron and steel manufacturing facilities and (2) new MACT
standards, in the form of opacity limits and work practice (WP)

standards, for five unregulated sources of UFIP emissions: Unplanned
Bleeder Valve Openings, Planned Bleeder Valve Openings, Slag Pits,
Beaching, and Bell Leaks. In this context, opacity is a measure of the
amount of light that is blocked or absorbed by an air pollution plume.
The components of air pollution that block or absorb light are
primarily particulate matter (PM), or PM. An opacity level of 0 percent
means that any plumes of air pollution do not block or absorb light and
are fully transparent (i.e., no visble emissions). On the other hand,
an opacity of 100 percent would mean that the plume is quite dense and
blocks all light (i.e., the trained observer or special camera can not
see any background behind the plume). Observers are trained and
certified using smoke generators which produce known opacity levels,
and periodic recertification is required every six months. More details
regarding the EPA approved method for opacity readings by a trained
observer are available at the following website: https://www.epa.gov/emc/method-9-visual-opacity. Alternatively, opacity can be observed
with special cameras following a specific method (known as the digital
camera opacity technique (DCOT), 40 CFR 63.7823), and those images
interpreted by trained individuals. For the Integrated Iron and Steel
Manufacturing (and a number of other metals processing and production
sectors), we know that a significant portion of the emitted PM is
comprised HAP metals (such as arsenic, lead, manganese, chromium) that
are primarily emitted in particulate form. Therefore, for this industry
as well as several other industries, PM serves as a surrogate for
particulate HAP metals.
    We are also proposing new emissions limits for three unregulated
pollutants for BF stoves and BOPFs: total hydrocarbons (THC), HCl, and
D/F, and for two unregulated pollutants for BFs: THC and HCl. In this
action, pursuant to CAA section 112(d)(6), we are also proposing to:
(1) Revise the current BOPF shop fugitive 20 percent opacity limit to a
5 percent opacity limit and require certain work practices; (2) revise
the current BF casthouse fugitive 20 percent opacity limit to a 5
percent opacity limit; (3) add a fenceline monitoring requirement to
help ensure the work practices and opacity limits are achieving the
anticipated reductions; and (4) revise standards for D/F and PAHs from
sinter plants to reflect the performance of current control devices.
3. Costs and Benefits
    To meet the requirements of E.O. 12866, the EPA projected the
emissions reductions, costs, and benefits that may result from the
proposed rule. These results are presented in detail in the regulatory
impact analysis (RIA) accompanying this proposal developed in response
to E.O. 12866. The proposed rule is significant under E.O. 12866
Section 3(f)(1), as amended by E.O. 14094 due to the monetized benefits
of fine particulate matter (PM2.5) reductions likely to
result from the UFIP emissions standards included in the proposed rule.
The RIA, which is available in the docket for this action, focuses on
the elements of the proposed rule that are likely to result in
quantifiable cost or emissions changes compared to a baseline without
the proposed regulatory requirements. We estimated the cost, emissions,
and benefit impacts for the 2025 to 2034 period, discounted to 2023. We
show the present value (PV) and equivalent annualized value (EAV) of
costs, benefits, and net benefits of this action in 2022 dollars. The
EAV represents a flow of constant annual values that would yield a sum
equivalent to the PV. The EAV represents the value of a typical cost or
benefit for each year of the analysis, consistent with the estimate of
the PV, in contrast to year-specific estimates.
    The initial analysis year in the RIA is 2025 because we assume that
will be the first year of full implementation of the rule. We are
proposing that facilities will have 1 year to demonstrate compliance
with the relevant standards following promulgation. This analysis
assumes full compliance with the proposed standards will occur in late
2024 given the expected promulgation of this rule in late 2023.
Therefore, the first full year of impacts will occur in 2025. The final
analysis year is 2034, which allows us to provide 10 years of projected
impacts after the rule takes effect.
    The cost analysis presented in the RIA reflects a nationwide
engineering analysis of compliance cost and emissions reductions.
Impacts are calculated by setting parameters on how and when affected
facilities are assumed to respond to a particular regulatory regime,
calculating estimated cost and emissions impact estimates for each
facility, differencing from the baseline scenario, and then summing to
the desired level of aggregation.
    The EPA expects health benefits due to the emissions reductions
projected from the rule. We expect that hazardous air pollutant (HAP)
emission reductions will improve health and welfare associated with
reduced exposure for those affected by these emissions. In addition,
the EPA expects that PM2.5 emission reductions that will
occur concurrent with the reductions in HAP emissions will improve air
quality and are likely to improve health and welfare associated with
exposure to PM2.5 and HAP. For the RIA, the EPA monetized
benefits associated with premature mortality and morbidity from reduced
exposure to PM2.5. Discussion of both the monetized and non-
monetized benefits can be found in Chapter 4 of the RIA.
    Table 1 presents the emission changes and the PV and EAV of the
projected monetized benefits, compliance costs, and net benefits over
the 2025 to 2034 period under the rule. All discounting of impacts
presented uses social discount rates of 3 and 7 percent.

 Table 1--Monetized Benefits, Costs, Net Benefits, and Emissions Reductions of the Proposed NESHAP Subpart FFFFF
                                         Amendments, 2025 Through 2034 a
                       [Dollar estimates in millions of 2022 dollars, discounted to 2023]
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                                          3 Percent discount rate                 7 Percent discount rate
                                 -------------------------------------------------------------------------------
                                          PV                  EAV                 PV                  EAV
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Benefits \b\....................  $2,300 and $2,400.  $260 and $280.....  $1,700 and $1,700.  $220 and $230.
Compliance Costs................  $39...............  $4.6..............  $32...............  $4.6.
Net Benefits....................  $2,300 and $2,400.  $260 and $280.....  $1,700 and $1,700.  $220 and $230.
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Emissions Reductions (short                                       2025-2034 Total
 tons).
    HAP.........................                                        790
    PM..........................                                      23,000

    PM2.5.......................                                       5,600
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Non-monetized Benefits in this    HAP benefits from reducing 790 short tons of HAP from 2025-2034.
 Table.
                                  Non-health benefits from reducing 23,000 tons of PM, of which 5,600 tons is
                                   PM2.5, from 2025-2034.
                                  Visibility benefits.
                                  Reduced ecosystem/vegetation effects.
----------------------------------------------------------------------------------------------------------------
\a\ Totals may not sum due to independent rounding. Numbers rounded to two significant digits unless otherwise
  noted.
\b\ Monetized benefits include health benefits associated with reductions in PM2.5 emissions. The monetized
  health benefits are quantified using two alternative concentration-response relationships from the Di et al.
  (2016) and Turner et al. (2017) studies and presented at real discount rates of 3 and 7 percent. The two
  benefits estimates are separated by the word ``and'' to signify that they are two separate estimates. Benefits
  from HAP reductions remain unmonetized and are thus not reflected in the table.

B. Does this action apply to me?

    Table 2 of this preamble lists the NESHAP and associated regulated
industrial source categories that are the subject of this proposal.
Table 2 is not intended to be exhaustive, but rather provides a guide
for readers regarding the entities that this proposed action is likely
to affect. The proposed standards, once promulgated, will be directly
applicable to the affected sources. Federal, State, local, and Tribal
government entities would not be affected by this proposed action. As
defined in the Initial List of Categories of Sources Under Section
112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576,
July 16, 1992) and Documentation for Developing the Initial Source
Category List, Final Report (see EPA-450/3-91-030, July 1992), the
Integrated Iron and Steel Manufacturing Facilities source category is
any facility engaged in producing steel from iron ore. Integrated iron
and steel manufacturing includes the following processes: sinter
production, iron production, iron preparation (hot metal
desulfurization), and steel production. The iron production process
includes the production of iron in BFs by the reduction of iron-bearing
materials with a hot gas. The steel production process includes BOPFs.

    Table 2--NESHAP and Industrial Source Categories Affected by This
                                Proposal
------------------------------------------------------------------------
         Source category                  NESHAP          NAICS code \1\
------------------------------------------------------------------------
Integrated Iron and Steel          40 CFR part 63,               331110
 Manufacturing Facilities.          subpart FFFFF.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

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

    In addition to being available in the docket, an electronic copy of
this action is available on the internet. Following signature by the
EPA Administrator, the EPA will post a copy of this proposed action at
https://www.epa.gov/stationary-sources-air-pollution/integrated-iron-and-steel-manufacturing-national-emission-standards. Following
publication in the Federal Register, the EPA will post the Federal
Register version of the proposal and key technical documents at this
same website.
    A memorandum showing the rule edits that would be necessary to
incorporate the changes to 40 CFR part 63, subpart FFFFF proposed in
this action is available in the docket (Docket ID No. EPA-HQ-OAR-2002-
0083). The EPA also will post a copy of this document to https://www.epa.gov/stationary-sources-air-pollution/integrated-iron-and-steel-manufacturing-national-emission-standards.

II. Background

A. What is the statutory authority for this action?

    This action proposes to amend the National Emission Standards for
Hazardous Air Pollutants (NESHAP) for the Integrated Iron and Steel
Manufacturing Facilities source category.
    The statutory authority for this action is provided by section 112
of the CAA, as amended (42 U.S.C. 7401, et seq.). In the first stage of
the CAA section 112 standard-setting process, the EPA promulgates
technology-based standards under CAA section 112(d) for categories of
sources identified as emitting one or more of the HAP listed in CAA
section 112(b). Sources of HAP emissions are either major sources or
area sources, and CAA section 112 establishes different requirements
for major source standards and area source standards. ``Major sources''
are those that emit or have the potential to emit 10 tons per year
(tpy) or more of a single HAP or 25 tpy or more of any combination of
HAP. All other sources are ``area sources.'' For major sources, CAA
section 112(d)(2) provides that the technology-based NESHAP must
reflect the maximum degree of emission reductions of HAP achievable
(after considering cost, energy requirements, and non-air quality
health and environmental impacts). These standards are commonly
referred to as MACT standards. CAA section 112(d)(3) also establishes a
minimum control level for MACT standards, known as the MACT ``floor.''
In certain instances, as provided in CAA section 112(h), the EPA may
set work practice standards in lieu of numerical emission standards.
The EPA must also consider control options that are more stringent than
the floor. Standards more stringent than the floor are commonly
referred to as ``beyond-the-floor'' (BTF) standards.
    CAA section 112(d)(6) requires the EPA to review standards
promulgated

under CAA section 112 and revise them ``as necessary (taking into
account developments in practices, processes, and control
technologies)'' no less often than every eight years. While conducting
this review, which we call the ``technology review,'' the EPA is not
required to recalculate the MACT floors that were established during
earlier rulemakings. Nat. Resources Def. Council (NRDC) v. EPA, 529
F.3d 1077, 1084 (D.C. Cir. 2008); Ass'n of Battery Recyclers, Inc. v.
EPA, 716 F.3d 667 (D.C. Cir. 2013). The EPA may consider cost in
deciding whether to revise the standards pursuant to CAA section
112(d)(6).
    CAA section 112(f) requires the EPA to determine whether
promulgation of additional standards is needed to provide an ample
margin of safety to protect public health or to prevent an adverse
environmental effect. This review is known as the ``residual risk
review,'' and it must occur within eight years after promulgation of
the standards. When EPA conducts the ``technology review'' together
with the ``residual risk review,'' the combined review is known as a
``risk and technology review'' or ``RTR.''
    The EPA initially promulgated the Integrated Iron and Steel
Manufacturing Facilities NESHAP on May 20, 2003 (68 FR 27645), under
title 40, part 63, subpart FFFFF (the NESHAP). The rule was amended on
July 13, 2006 (71 FR 39579). The amendments added a new compliance
option, revised emission limitations, reduced the frequency of repeat
performance tests for certain emission units, added corrective action
requirements, and clarified monitoring, recordkeeping, and reporting
requirements.
    In 2015, a coalition of environmental advocacy groups filed a
lawsuit to compel the EPA to fulfill its statutory duty to conduct the
CAA sections 112(d) and 112(f)(2) reviews of 21 NESHAPs, including
Integrated Iron & Steel Manufacturing Facilities. As a result of that
litigation, the EPA was required by court order to complete the RTR for
the Integrated Iron and Steel Manufacturing Facilities source category
by May 5, 2020. California Communities Against Toxics v. Wheeler, No.
1:15-cv-00512, Order (D.D.C. March 13, 2017, as modified February 20,
2020). The resulting residual risk and technology review (RTR)
conducted for the Integrated Iron and Steel Manufacturing Facilities
NESHAP was signed on May 4, 2020. 85 FR 42074 (July 13, 2020).
    In an April 2020 decision by the U.S. Court of Appeals for the
District of Columbia Circuit, the court held that the EPA has an
obligation to address unregulated HAP emissions from a source category
when the Agency conducts the eight-year technology review required by
CAA section 112(d)(6). LEAN, 955 F.3d at 1098-99. The parties in the
California Communities Against Toxics case therefore filed a joint
motion for an extension of the deadline to allow the EPA to revise the
2020 final rule to comply with the LEAN opinion. The court granted the
motion, setting a new deadline for this rule of October 26, 2023.
California Communities Against Toxics, Order (D.D.C. April 14, 2021).
    And finally, in September 2021, industry and environmental advocacy
groups filed petitions for review of the 2020 final rule, and these
petitions have been consolidated. American Iron and Steel Inst., et al.
v. EPA, No. 20-1354 (D.C. Cir.); Clean Air Council, et al. v. EPA, No.
20-1355 (D.C. Cir.). The consolidated case is in abeyance pending this
rulemaking. American Iron and Steel Inst., No. 20-1354 (consol.),
Order, Dec. 7, 2022.
    In light of this litigation history, today's proposed rule
includes: (1) Proposed new standards to address currently unregulated
emissions of HAP from the Integrated Iron and Steel Manufacturing
Facilities source category pursuant to the LEAN decision and CAA
sections 112(d)(2) and (3) and 112(h) and, (2) proposed revised
standards for a few currently regulated HAP and fenceline monitoring
requirements pursuant to the CAA section 112(d)(6) technology review.

B. What is this source category and how does the current NESHAP
regulate its HAP emissions?

    As described above, the Integrated Iron and Steel Manufacturing
Facilities source category includes any facility engaged in producing
steel from refined iron ore (also known as taconite pellets). These
facilities first produce iron from iron ore taconite pellets, sinter,
coke, and other raw materials using blast furnaces (BFs), then produce
steel from the hot liquid iron from the blast furnaces, along with
coke, lime, alloys, steel scrap, and other raw materials using basic
oxygen process furnaces (BOPFs). Integrated iron and steel
manufacturing includes the following processes: sinter production, iron
production, iron preparation (hot metal desulfurization), and steel
production. The iron production process includes the production of iron
in BFs by the reduction of iron-bearing materials with a very hot gas.
The steel production process includes BOPFs and ladle metallurgy
operations. Currently there are eight operating facilities in this
source category.
    The main sources of HAP emissions from integrated iron and steel
manufacturing are the BF; BF stove; BOPF; hot metal transfer,
desulfurization, and skimming (HMTDS) operations; ladle metallurgy
operations; sinter plant windbox; sinter plant discharge end; and
sinter cooler. All nine facilities have BFs, BF stoves, BOPFs, HMTDS
operations, and ladle metallurgy operations. However, only three
facilities have sinter plants.
    The following are descriptions of the BF, BOPF, and sinter plants:
     The BF is a key integrated iron and steel process unit
where molten iron is produced from raw materials such as iron ore,
lime, sinter, coal and coke.
     The BOPF is a key integrated iron and steel process unit
where steel is made from molten iron, scrap steel, lime, dolomite,
coal, coke, and alloys.
     Sinter is derived from material formed in the bottom of
the blast furnace, composed of oily scale, blast furnace sludge, and
coke breeze, along with tarry material and oil absorbed from the sump
in which the sinter is recovered. The sinter plant processes the waste
that would otherwise be landfilled so that iron and other valuable
materials can be re-used in the blast furnace. Only three sources
covered by the Integrated Iron and Steel Manufacturing Facility
category have sinter plants, down from nine facilities with sinter
plants in 2003.
    In addition to point sources, the EPA identified seven UFIP
emission sources for this source category, including BF bleeder valve
unplanned openings BF bleeder valve planned openings, BF bell leaks, BF
casthouse fugitives, BF iron beaching, BF and BOPF slag handling and
storage operations, and BOPF shop fugitives. Some of these UFIP sources
are also referred to as ``fugitive'' or ``nonpoint'' sources of
emissions. These UFIP emission sources were identified by observation
of visible plumes by EPA regional staff during onsite inspections and
were subsequently investigated to determine the causes and any possible
methods for reductions. These inspections were documented in numerous
reports and photographs between 2008 and the present.\1\ The NESHAP
currently regulates two of these sources--BF casthouse fugitives

and BOPF shop fugitives--with opacity limits.
---------------------------------------------------------------------------

    \1\ E.g., communications between B. Dickens and P. Miller, U.S.
EPA Region V, Chicago, IL, with D. L. Jones, U.S. EPA, Office of Air
Quality Planning and Standards, Office of Air and Radiation, 2015-
2018. See also Ample Margin of Safety for Nonpoint Sources in the
II&S Industry, available in the docket to this rule.
---------------------------------------------------------------------------

    The following are descriptions of the seven UFIP sources. More
details can be found in the technical memoranda discussed below in
Section II.D.
     The BF is a key integrated iron and steel process unit
where molten iron is produced from raw materials such as iron ore,
lime, sinter, coal and coke.
     The BOPF is a key integrated iron and steel process unit
where steel is made from molten iron, scrap steel, lime, dolomite,
coal, coke, and alloys.
     Sinter is derived from material formed in the bottom of
the blast furnace, composed of oily scale, blast furnace sludge, and
coke breeze, along with tarry material and oil absorbed from the sump
in which the sinter is recovered. The sinter plant processes the waste
that would otherwise be landfilled so that iron and other valuable
materials can be re-used in the blast furnace. Only three sources
covered by the Integrated Iron and Steel Manufacturing Facility
category have sinter plants, down from nine facilities with sinter
plants in 2003.
     The BOPF shop is the structure that houses the entire BOPF
and auxiliary activities, such as hot iron transfer, skimming, and
desulfurization of the iron and ladle metallurgy operations, which
generate fugitive emissions.
     The BF casthouse is the structure that houses the lower
portion of the BF and encloses the tapping operation and the iron and
slag transport operations, which generate fugitive emissions.
     The bleeder valve is a device at the top of the BF that,
when open, relieves BF internal pressure to the ambient air. The valve
can operate as both a self-actuating safety device to relieve excess
pressure and as an operator-initiated instrument for process control. A
bleeder valve opening means any opening of the BF bleeder valve, which
allows gas and/or PM to flow past the sealing seat. Multiple openings
and closings of a bleeder valve that occur within a 30-minute period
could be considered a single bleeder valve opening. There are two types
of openings, planned and unplanned.
     A planned bleeder valve opening means an opening that is
initiated by an operator as part of a furnace startup, shutdown, or
temporary idling for maintenance action. Operators can prepare the
furnace for planned openings to minimize or eliminate emissions from
the bleeder valves.
     An unplanned bleeder valve opening means an opening that
is not planned and is caused by excess pressure within the furnace. The
pressure buildup can occur when raw materials do not descend smoothly
after being charged at the top of the BF and accumulate in large masses
within the furnace. When the large masses finally dislodge (slip) due
to their weight, a pressure surge results.
     Slag is a by-product containing impurities that is
released from the BF or BOPF along with molten iron when the BF or BOPF
is tapped from the bottom of the furnace. The slag is less dense than
iron and, therefore, floats on top of the iron. Slag is removed by
skimmers and then transported to open pits to cool to enable later
removal. Usually there is one slag pit for every BF or BOPF.
     Iron beaching occurs when iron from BF cannot be charged
to the BOPF because of problems in steelmaking units; the hot molten
iron from the BF is placed onto the ground, in some cases within a
three-sided structure.
     The BF bells are part of the charging system on top of the
furnace that allows for materials to be loaded into the furnace or next
bell (as in the case of small bells) without letting BF gas escape. It
is a two-bell system, where a smaller bell is above a larger bell.
These bells need to have a tight seal onto the blast furnace when not
in use for charging so that BF gas and uncontrolled emissions do not
escape to the atmosphere. Over time, the surfaces that seal the bells
wear down and need to be repaired (for small bells) or replaced (for
large bells). If these seals are not repaired or replaced in a timely
manner, emissions of HAP and PM can increase significantly.
    In the 2020 final rule, the Agency found that risks due to
emissions of air toxics from this source category were acceptable and
concluded that the NESHAP provided an ample margin of safety to protect
public health. Under the technology review in the 2020 RTR, EPA found
no developments in practices, processes, or control technologies that
necessitated revision of the standards at that time. However, in
response to a 2004 administrative petition for reconsideration, the
2020 final rule promulgated a new MACT emissions limit for mercury
(0.00026 lbs mercury/ton scrap metal) with two compliance options: (1)
Conduct annual compliance tests (to demonstrate compliance with the
MACT limit) or (2) confirm that the facility obtains their auto scrap
from suppliers that participate in the National Vehicle Mercury Switch
Recovery Program (NVMRP) or another approved mercury switch removal
program or that the facility only uses scrap that does not contain
mercury switches. We also removed exemptions for periods of startup,
shutdown, and malfunction (SSM) consistent with a 2008 court decision
and clarified that the emissions standards apply at all times; added
electronic reporting of performance test results and compliance
reports; and made minor corrections and clarifications for a few other
rule provisions. All documents used to develop the previous 2003, 2006,
and 2020 final rules can be found in either the legacy docket, A-2000-
44, or the electronic docket, EPA-HQ-OAR-2002-0083.
    The current NESHAP includes emissions limits for particulate matter
(PM) and opacity standards (both of which are surrogates for non-
mercury PM HAP metals) for furnaces and sinter plants. To support the
continued use of PM as a surrogate for certain non-mercury HAP metals,
we considered the holding in National Lime v. EPA, 233 F.3d 625 (D.C.
Cir. 2000). In considering whether the EPA may use PM, a criteria
pollutant, as a surrogate for metal HAP, the D.C. Circuit stated that
the EPA ``may use a surrogate to regulate hazardous pollutants if it is
`reasonable' to do so,'' id. at 637, and laid out criteria for
determining whether the use of PM as a surrogate for non-mercury metal
HAP was reasonable. The court found that PM is a reasonable surrogate
for HAP if: (1) ``HAP metals are invariably present'' in the source's
PM,'' id.; (2) the ``source's PM control technology indiscriminately
captures HAP metals along with other particulates,'' id. at 639; and
(3) ``PM control is the only means by which facilities `achieve'
reductions in HAP metal emissions,'' id. If these criteria are
satisfied and the PM emission standards reflect what the best sources
achieve in compliance with CAA section 112(d)(3), ``EPA is under no
obligation to achieve a particular numerical reduction in HAP metal
emissions.'' Id. The EPA has established and promulgated PM limits as a
surrogate for particulate HAP metals successfully in several previous
NESHAP including Ferroalloys Production (80 FR 37366, June 30, 2015),
Taconite Iron Ore Processing NESHAP (68 FR 61868), and Primary Copper
Smelting NESHAP (67 FR 40478, June 12, 2002).
    The NESHAP also includes an operating limit for the oil content of
the sinter plant feedstock or, as an alternative, an emissions limit
for volatile organic compounds (VOC) for the sinter plant windbox
exhaust stream. The oil limit, and the alternative VOC limit, serve as
surrogates for all organic HAP. Moreover, the NESHAP includes an
emissions limit for mercury emissions from the BOPF Group, which

is the collection of BOPF shop steelmaking operating units and their
control devices including the BOPF primary emission control system,
BOPF secondary control system, ladle metallurgy units, and hot metal
transfer, desulfurization and slag skimming units.

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

    The EPA issued a CAA section 114 information request in January
2022, including a facility questionnaire and source testing request, to
both parent companies in this source category, resulting in information
for all eight operating facilities. The questionnaire requested
information in the following categories: general facility information,
process unit tables, and UFIP emission information. Facility responses
provided information regarding which UFIP work practices are currently
being utilized or have been tried in the past, and any benefits,
drawbacks, or complications of each one. They also provided information
about the frequencies of some of their intermittent emissions, such as
planned and unplanned bleeder valve openings. The compilation of the
facility responses can be found in the docket for this proposed
rulemaking (EPA-HQ-OAR-2002-0083). The information we received on UFIP
emissions helped us develop the standards in this proposed rule. The
EPA requested source testing for HAP metals and hydrogen fluoride (HF)
at the sinter plant windbox control device and opacity data for the
fugitive and intermittent particulate sources. In addition, the EPA
requested fenceline monitoring for lead, arsenic and chromium at four
facilities.
    In September 2022, the EPA issued a supplemental CAA section 114
information request for additional source testing at one facility for
each parent company. From one facility, we requested source testing for
HCl and total hydrocarbons for the BF stove, BF casthouse, and the BOPF
primary control device, as well as source testing for D/F from the BF
stove and the BOPF primary control device. From the other facility, we
requested source testing for HCl and D/F from the BOPF primary control
device, as well as source testing for D/F at the outlet of the boiler
from the BF stove. One additional facility voluntarily submitted test
reports for HCl and THC for the BF stove and BF casthouse, as well as
THC source testing for the BOPF primary control device. These data were
gathered to supplement data we already had from the 2020 RTR rule
development, which is described in the 2019 RTR proposed on August 16,
2019 (84 FR 42704), and in technical support documents cited in that
notice. The compilation of source testing results can be found in the
docket for this action (EPA-HQ-OAR-2002-0083).

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

    The EPA used several resources, including industry consultation,
AP-42 Compilation of Air Pollutant Emission Factors, Fifth Edition,
dated January 15, 1995, as amended with Supplements and Updates, EPA
studies, and other published technical documents to estimate emissions
for the UFIP sources. The seven UFIP sources and development of
emissions estimates for these sources at an example facility are
described in detail in three technical memoranda. The first, Ample
Margin of Safety for Nonpoint Sources in the II&S Industry May 1, 2019,
available in the docket for this rule (EPA-HQ-OAR-2002-0083-0953),
describes the seven UFIP sources, work practices that can help reduce
or minimize HAP and PM emissions, estimated costs of these work
practices, and estimated risks before and after implementation of work
practices based on the 2019-2020 RTR rulemaking analyses. The second,
Development of Emissions Estimates for Fugitive or Intermittent HAP
Emission Sources for an Example Integrated Iron and Steel Manufacturing
Facility for Input to the RTR Risk Assessment 5/1/2020, also available
in the docket (EPA-HQ-OAR-2002-0083-1094), describes the following: (1)
The development of emissions estimates for UFIP from processes where
emissions from UFIP are thought to occur; (2) estimates of PM emissions
from these processes; (3) HAP-to-PM ratios used to estimate HAP
emissions from the PM emissions estimates; and (4) the resulting HAP
emissions estimated. These two memoranda were developed to support the
2019 proposed RTR rule and the 2020 final RTR rule.
    We further developed updated estimates of HAP, PM, and
PM2.5 emissions from the UFIP at all other operating
Integrated Iron and Steel Manufacturing Facility sources, which are
described in the third and most recent 2023 memorandum, Unmeasured
Fugitive and Intermittent Particulate Emissions and Cost Impacts for
Integrated Iron and Steel Facilities under 40 CFR part 63, subpart
FFFFF, available in the docket for this action.
    Also, regarding the proposed requirements for the UFIP sources
(described below), industry representatives provided additional
information including suggested opacity limits and work practices (and
suggested regulatory text).\2\ Furthermore, we received additional data
and information from industry in April, but we were unable to review
and analyze this information for this proposal given the timing of its
submission.\3\ We solicit comments on the information and suggestions
that industry provided including whether EPA should adopt some or all
of these suggestions and a thorough explanation as to why, or why not.
---------------------------------------------------------------------------

    \2\ See February 22, 2023 email from Paul Balserak, American
Iron and Steel Institute (AISI), and the attachment to that email,
``II&S DRAFT PROPOSED RULE UFIP LANGUAGE,'' available in the docket
for this action.
    \3\ See April 12, 2023 email from Paul Balserak, AISI, and two
attachments, ``PRELIMINARY FEEDBACK ON POTENTIAL STANDARDS FOR THE
INTEGRATED IRON AND STEEL MANUFACTURING NESHAP'' & ``Attachment A to
Supp to Jan and Feb Submittals,'' available in the docket for this
action.
---------------------------------------------------------------------------

III. Analytical Procedures and Decision-Making

A. How do we perform the technology review?

    Our technology review primarily focuses on the identification and
evaluation of developments in practices, processes, and control
technologies that have occurred since the MACT standards were
promulgated. Where we identify such developments, we analyze their
technical feasibility, estimated costs, energy implications, and non-
air health and environmental impacts. The EPA also considers the
emission reductions associated with applying each development. This
analysis informs our decision of whether it is ``necessary'' to revise
the emissions standards. In addition, the Agency considers the
appropriateness of applying controls to new sources versus retrofitting
existing sources. For this exercise, the EPA considers any of the
following to be a ``development'':
     Any add-on control technology or other equipment that was
not identified and considered during development of the original MACT
standards;
     Any improvements to the add-on control technology or other
equipment that was identified and considered during development of the
original MACT standards that could result in additional emissions
reductions;
     Any work practice or operational procedure that was not
identified or considered during development of the original MACT
standards;
     Any process change or pollution prevention alternative
that could be broadly applied to the industry and that was not
identified or considered during development of the original MACT
standards; and

     Any significant changes in the cost (including cost
effectiveness) of applying controls, including controls the EPA
considered during the development of the original MACT standards.
    In addition to reviewing the practices, processes, and control
technologies that were considered at the time the EPA originally
developed the NESHAP, we review a variety of data sources in our
investigation of potential practices, processes, or controls to
consider. The EPA also reviews the NESHAP and the available data to
determine whether there are any unregulated emissions of HAP within the
source category and evaluates the data for use in developing new
emission standards. See sections II.C and II.D of this preamble for
information on the specific data sources that were reviewed as part of
the technology review.

B. How do we develop and calculate CAA section 112(d)(2) and (3)
standards?

    The MACT floor limits for relevant HAP are calculated based on the
average performance of the best-performing five units in each category
or subcategory and on a consideration of these units' variability. The
MACT floor for new sources is based on the single best-performing
source, with a similar consideration of that source's variability. The
MACT floor for new sources cannot be less stringent than the emissions
performance that is achieved in practice by the best-controlled similar
source. To account for variability in the operation and emissions, we
calculated the MACT floor emissions limits for this source category
using the 99 percent Upper Predictive Limit (UPL) using the available
stack emissions test results. We note that the MACT floor limits for
new units are based on a limited data set.\4\
---------------------------------------------------------------------------

    \4\ For more information regarding the general use of the UPL
and why it is appropriate for calculating MACT floors, see Use of
Upper Prediction Limit for Calculating MACT Floors (UPL Memo), which
is available in the docket for this action.
---------------------------------------------------------------------------

    The UPL approach addresses variability of emissions test data from
the best-performing source or sources in setting MACT standards. The
UPL also accounts for uncertainty associated with emission values in a
dataset, which can be influenced by components such as the number of
samples available for developing MACT standards and the number of
samples that will be collected to assess compliance with the emission
limit. The UPL approach has been used in many environmental science
applications. As explained in more detail in the UPL Memo cited above,
the EPA uses the UPL approach to reasonably estimate the emissions
performance of the best-performing source or sources to establish MACT
floor standards when the EPA has emissions test data that allow for
such calculations.
    After the MACT floor limits are developed, the EPA also evaluates
potential beyond-the-floor (BTF) options (i.e., more stringent options)
to determine whether there are cost-effective appropriate standards
that can achieve additional reductions that should be proposed instead
of the MACT floor standards.

IV. Analytical Results and Proposed Decisions

A. Proposed Standards To Address Five Unregulated UFIP Sources for Both
New and Existing Sources

1. BF Unplanned Bleeder Valve Openings
    Sometimes raw material within the BF builds up, fails to descend
smoothly, and falls or slips. Sometimes these slips create a pressure
surge that is relieved, along with excess pollutant emissions (e.g., PM
with HAP metals), out of bleeder valves that are positioned about 100
feet above the casthouse. If the slip results in the valve opening, we
call this an ``unplanned opening.'' Unplanned openings can last between
a few seconds and ten minutes, and occur between 0 to 7 times per
month, and fewer slips and fewer unplanned openings occur with better
screening of raw material and more attentive furnace operation to
enable early action to avoid unplanned openings. Based on the data we
received through the section 114 requests, the average number of
unplanned openings of the best performing five furnaces in the source
category is 5 unplanned openings per year. Therefore, we estimate that
the MACT floor level of performance is 5 unplanned openings per year.
    All slips are preceded by raw material hanging in the furnace,
creating a bridge. It is our understanding that because furnaces have
level indicators, furnace operators should know when conditions for a
slip are forming, and if they are forming, operators should be able to
take action to induce a small slip that can avoid a larger slip that
ultimately causes an unplanned bleeder valve opening. It is our
understanding that hanging of raw material can be avoided or
significantly reduced by screening fine particulates from the raw
material. Therefore, unplanned openings should be limited to a
significant extent by operators monitoring the furnace and taking
actions when certain parameter readings indicate a slip may occur.
    We estimate that about 2.1 tpy of HAP metals are emitted from the
Integrated Iron and Steel source category due to these unplanned
openings. Because unplanned openings are variable, only last for up to
10 minutes, and due to the structure of the bleeder valves, it is not
technically or economically feasible to reliably measure emissions from
unplanned openings. Therefore, based on our evaluation of available
information, pursuant to CAA section 112(d)(2) and (3) and CAA section
112(h), we are proposing work practice standards that would require
facilities to do the following: (1) Install and operate devices (e.g.,
stockline monitors) to continuously measure/monitor material levels in
the furnace, at a minimum of three locations, using alarms to inform
operators of static conditions that indicate a slip may occur, and
therefore, in turn, alert them that there is a need to take action to
prevent the unplanned openings from occurring; (2) install and operate
instruments such as a thermocouple and transducer on the furnace to
monitor temperature and pressure to help determine when a slip may
occur; (3) install a screen to remove fine particulates from raw
materials to ensure only properly-sized raw materials are charged into
the BF; and (4) develop, and submit to the EPA for approval, a plan
that explains how the facility will implement these requirements.
Additionally, we are proposing that facilities will need to report the
unplanned openings (including the date, time, duration, and any
corrective actions taken) in the semiannual compliance report.
    In addition to the proposed work practices, we are also proposing
an operational limit of five unplanned openings per year per furnace
for existing sources, which is an estimate of the MACT floor level of
performance for existing sources. For new sources, we are proposing an
operational limit of zero unplanned openings per year because the best
performing single source in our database reported zero unplanned
openings for the most recent typical year.
    We estimate that the costs for the entire industry for these
proposed standards would be $1,470,000 and annualized costs would be
$239,800, for the eight facilities to comply with these work practice
requirements, and that these requirements will result in about 0.5 tpy
emissions reductions.
    We propose that the limit of 5 unplanned openings per year per
furnace and the work practice standards described above are a
reasonable

estimation of the MACT floor level of performance (i.e., represent a
reasonable estimate of the average performance of the best performing
five sources). Furthermore, we did not identify any cost-effective and
appropriate BTF options. Nevertheless, we solicit comments regarding:
(1) Whether EPA should change or remove any of the specific work
practices described above, and, if so, an explanation including any
related analysis to support as to why or why not; (2) whether there are
cost-effective BTF options; (3) whether EPA should consider a different
number of unplanned openings per year (e.g., 3, 6, or 10 unplanned
openings per year, or a different value), and if so, why; (4) whether
the limit should be an enforceable compliance limit or an action level
that triggers the need to do root cause analyses and take corrective
action; and (5) are there furnace design differences that affect
operations related to unplanned openings. Furthermore, we solicit
comments on the cost estimates for all aspects of these proposed
requirements, including costs for the recordkeeping and reporting
requirements, and we solicit data and suggestions regarding any other
aspect of these proposed requirements that we should consider as we
develop the final rule, including any additional data regarding how
many unplanned openings have occurred per year (e.g., for the past five
years) for the various blast furnaces in the source category.
    Further information and analyses (regarding the proposed MACT
standard, BTF options and other relevant topics) are available in the
document titled Unmeasured Fugitive and Intermittent Particulate
Emissions and Cost Impacts for Integrated Iron and Steel Facilities
under 40 CFR part 63, subpart FFFFF which is available in the docket
2. BF Planned Bleeder Valve Openings
    Bleeder valves are opened periodically to allow repair or other
maintenance. The furnace is turned down to low idle before valves are
opened, which results in lower emissions than during unplanned
openings. It is our understanding that planned openings happen up to 2
times per week for repairs or for maintenance for a total average of
approximately 15 hours per week per furnace. We estimate that source
category emissions resulting from these planned openings are about 1.6
tpy of HAP metals.
    We received opacity data from six of the eight operating facilities
for planned openings. We reviewed the maximum 6-minute opacity readings
for all six facilities. Based on the 2022 data, the two best-performing
facilities had maximum 6-minute opacity readings of 0 percent and 6.25
percent, respectively. The average opacity readings at these two
facilities are 0 percent and 3.39 percent respectively. The average of
the maximum 6-minute opacity values for the best performing five
facilities is 7.75 percent (rounded to 8 percent). In calculating the
opacity limit, we did not apply the standard UPL approach (described in
section III.B of this preamble) because that method has not been used
in the past when calculating opacity limits. More information and
explanation regarding opacity, especially in the context of EPA
emissions standards, is provided in section II.A.2 of this preamble.
More information regarding the UFIP sources and the development of
proposed standards for UFIP sources are provided in the document titled
Unmeasured Fugitive and Intermittent Particulate Emissions and Cost
Impacts for Integrated Iron and Steel Facilities under 40 CFR part 63,
subpart FFFFF, which is in the docket for this proposed rule.
    We estimate that the ``MACT floor'' is the average of the maximum
6-minute opacity levels, which is 8 percent. We also evaluated a limit
of 5 percent opacity as a potential BTF option for existing sources. We
also determined based on evaluation of available information that
emissions can be minimized from bleeder valve planned openings cost
effectively by implementing various actions before the valves are
opened such as: (1) Tapping as much liquid (iron and slag) out of the
furnace as possible; (2) removing fuel and/or stopping fuel injection
into the furnace; and (3) lowering bottom pressure.
    Based on our evaluation of available information, pursuant to CAA
section 112(d)(2) and (3) for existing sources we are proposing a MACT
Floor limit of 8 percent opacity for any 6-minute averaging period for
the BF planned bleeder valve openings. For new sources, we are
proposing an opacity of 0 percent because based on the available data,
the best performing single source had opacity of 0 percent during the
planned opening. We are not proposing the BTF option of 5 percent
opacity for existing sources because we assume 5 percent opacity may
not be feasible for some sources on a consistent basis. We are not
proposing any work practices under CAA section 112(h) for the BF
planned bleeder valve openings. Facilities will have the flexibility to
choose an appropriate approach to meet the opacity limit. We estimate
that this proposed standard will result in about 0.41 tpy reduction in
HAP metal emissions. The estimated cost is $54,600/yr for the entire
category and $6,800/yr per facility. The estimated cost effectiveness
is $134,000 per ton of HAP metals.
    We solicit comments and additional information regarding these
proposed requirements, including: (1) Comments regarding the proposed
opacity limits, including the level of the opacity limits and averaging
time; (2) whether the EPA should apply the UPL approach (or other
statistical approach) to derive the opacity limits for UFIP sources and
if so an explanation of the suggested application of the UPL or other
statistical approach to derive opacity limits; (3) whether the EPA
should promulgate work practices instead of the opacity limits and a
description of those work practices; and (4) whether the EPA should
promulgate work practices and the opacity limits.
3. BF and BOPF Slag Processing, Handling, and Storage
    Slag (liquid waste on the surface of molten iron or steel) is
skimmed and transported out of buildings in troughs (or ``runners'') or
by using pots to large pits where it cools. Emissions occur during four
activities: (1) dumping of hot slag in pits; (2) storing slag in open
pits; (3) removing slag from pits with loaders, and; (4) handling
(e.g., movement into and out of trucks and slag piles), storage, and
processing. Operators can spray water on the slag or use fogging
systems, which create and direct fog (tiny water droplets or ice
crystals suspended in the air) into the slag area to weigh down and
minimize PM (or dust) emissions during dumping, loading, and digging
operations. We estimate that about 30 tpy of HAP metals are emitted
from slag processing, handling, and storage for the source category.
    We received opacity data from seven of the eight operating
facilities. We reviewed the maximum 6-minute opacity readings for all
seven facilities. The average of the maximum 6-minute opacity values
for the best performing five facilities is 9 percent. Based on the 2022
data, the two best-performing facilities in our dataset had maximum
opacity readings of 2.5 percent and 5 percent, respectively. The
average opacity readings at these two facilities are 0.2 percent and
1.2 percent, respectively. We did not apply the standard UPL approach
for the same reasons discussed above. Nevertheless, this average of
maximum opacity values suggests that the ``MACT floor'' is
approximately 9 percent. We also evaluated a limit of 5 percent opacity
as

a potential BTF option. We also determined based on evaluation of
available information that emissions can be minimized from slag pits
cost effectively with the application of water spray or fogging. Also,
other work practices such as installing wind screens, dust suppression
misters, a high moisture content of the slag during handling, storage,
and processing and using material handling practices can help minimize
emissions. Therefore, based on our analyses, pursuant to CAA section
112(d)(2) and (3), for existing sources we are proposing a BTF opacity
limit of 5 percent (based on 6-minute averages) for visible emissions
from slag pits, and during slag handling, storage, and processing. This
will result in an estimated 7.4 tpy reduction in HAP metal emissions.
The estimated cost is $308,000 per year for the entire category and
$38,500 per year per facility. The estimated cost effectiveness is
$41,900 per ton of HAP metals. Regarding new sources, we are proposing
an opacity limit of 2.5 percent (based on 6-minute averages) for
visible emissions from slag pits, and during slag handling, storage,
and processing.
    However, regarding the proposed limit for existing sources, we are
soliciting comments as to the feasibility of the 5 percent BTF opacity
limit for other facilities in the source category, and also soliciting
comments as to whether the EPA should set the opacity limit at the MACT
floor level (i.e., 9 percent opacity based on 6-minute averages), or
possibly at a lower, more stringent value, instead of the 5 percent BTF
opacity limit, and if so why, or why not. We also solicit comments and
data regarding the proposed opacity limit for new sources.
4. BF Bell Leaks
    Large and small bells are part of a lock system above the BF that
is used to charge raw materials into the BF without gases escaping. The
bells have metal seals that wear down over time from mechanical use and
movement of bells (they open to charge, then close when charge is done,
frequently, which results in frequent contact between the metal parts,
which leads to wear and tear overtime). Overtime, the seals wear down
or are damaged, which eventually results in gases being emitted to the
atmosphere. Therefore, the bells need to be repaired or replaced
periodically to prevent emissions. We estimate that about 76 tpy of HAP
metals are emitted from Bell Leaks for the source category.
    Based on our evaluation, pursuant to CAA section 112(d)(2) and (3),
we are proposing 10 percent opacity as an action level for large bell
leaks (not a MACT emissions limit), as described below. We are also
proposing that the BF top will need to be observed monthly for visible
emissions (VE) with EPA Method 22, 40 CFR part 60, appendix A-7, which
determines the presence or absence of a visible plume, to identify
leaks, and if VE are detected out of the interbell relief valve
(indicating leaks from the large bell), we are proposing that the
facility would then need to perform EPA Method 9, 40 CFR part 60,
appendix A-4, tests which determines the opacity (i.e., degree to which
a plume obscures the background), monthly and if opacity is greater
than 10 percent (based on a 3-minute average), the large bell seals
will need to be repaired or replaced within 4 months. For the small
bell, we are proposing that facilities will need to replace or repair
seals prior to a metal throughput limit, specified by the facility,
that has been proven and documented to produce no opacity from the
small bells. This will result in an estimated 31 tpy reduction in HAP
metal emissions. The estimated cost is $935,000 per year for the entire
category and $120,000 per facility. The estimated cost effectiveness is
$30,000 per ton of HAP metals. There could potentially be some
additional incremental costs due to this proposed requirement due to
the possible need to repair or replace the seals more frequently than
facilities currently do the repairs or replacement to account for
additional capital costs and loss of production due to more frequent
furnace shutdowns to do such repairs or replacement, however, we have
insufficient information to estimate these possible additional
incremental costs at this time.
    We are soliciting comments regarding these proposed requirements,
including whether the opacity action level should be set at a higher or
lower percent value and, if so, for what averaging period. We also
solicit comments regarding all other aspects of these proposed
requirements including the 4-month time period (to repair or replace
seals) described above, and the estimated costs (including costs due to
loss production, if any) and emissions reductions associated with these
proposed requirements.
5. Beaching of Iron From BFs
    When the BOPF is stopped suddenly and cannot accept iron, then hot
iron from the BF is dumped onto the ground and fumes are emitted. We
estimate that less than 1 tpy of HAP metals are emitted from beaching
for the source category.
    Available data and responses to the 2022 CAA section 114 request
indicate that one facility does not have beaching and another facility
had not done any beaching for 3 years (2019, 2020, or 2021). Of the
remaining six operating facilities, four facilities have full or
partial enclosures or use CO2 to suppress fumes, and all six
facilities minimize the height, slope, and speed of beaching.
Therefore, we conclude these actions approximately represent the MACT
floor level of performance. Furthermore, we did not identify any more
stringent cost-effective BTF options. For these reasons, pursuant to
CAA section 112(d)(2) and (3) and CAA section 112(h), we are proposing
a MACT standard that would require facilities to: (1) Have full or
partial enclosures for the beaching process or use CO2 to
suppress fumes; and (2) minimize the height, slope, and speed of
beaching. We expect this will result in a small amount of unquantified
emission reductions since baseline emissions are already low (less than
1 tpy of HAP) and because most facilities are already following some or
all of these work practices. The estimated cost is $55,000 per year for
the entire category and an average annual cost of $6,800 per facility.
More information regarding the proposed standards, and the BTF options
considered, for unregulated UFIP sources is available in the following
document: Unmeasurable Fugitive and Intermittent Particulate Emissions
and Cost Impacts for Integrated Iron and Steel Facilities under 40 CFR
part 63, subpart FFFFF, which is available in the docket for this
action.
    We solicit comments and additional information regarding all
aspects of these proposed beaching requirements.

B. Reconsideration of BF Casthouse and BOPF Shop Standards for
Currently Regulated Fugitive Sources Under CAA 112(d)(6) Technology
Review for Both New and Existing Sources

1. How did we develop the proposed revised CAA section 112(d)(6)
technology review standards for BOPF shop fugitive emissions?
    The BOPF shop fugitive emissions occur from hot metal and scrap
charging, tapping steel, hot metal transfer, and metallurgical
processes. Hoods collect some fugitives and route them to controls.
Uncaptured fugitives exhaust through roof vents, doors, or other
openings such as removed or damaged sections of the enclosure or
building that were not part of the original design. We estimate the
current total emissions from BOPF shops in the source category are
about 123 tpy of HAP metals (such as manganese, arsenic, chromium and
lead). The

current NESHAP has a 20 percent opacity limit for the BOPF shop.
    When EPA was developing the 2020 RTR, EPA had very limited data
regarding the opacity levels being achieved by facilities at that time
and limited data regarding the types of work practices being applied by
facilities. The EPA explained in the 2019 proposed rule (84 FR 42704,
August 16, 2023), and again in the 2020 final rule (85 FR 42074, July
13, 2020) that EPA did not propose any of these work practices
primarily because there were significant uncertainties in the technical
assessment of UFIP emissions that included estimates of the baseline
UFIP emissions, the estimated HAP reductions that would be achieved by
the work practices, and the costs of the work practices. In addition,
EPA also stated that there were uncertainties in the effect the work
practices would have on facility operations, economics, and safety.
    Based on our review and analyses of the CAA section 114 information
request responses we received in 2022 and 2023, and further review of
the data and analyses the EPA assembled to support the 2020 RTR, we now
conclude that a standard comprising a 5 percent opacity limit with
several specific work practices is feasible and cost effective. For
example, based on the data we received, the maximum 3-minute opacity
readings for the BOPF shops at four facilities are less than 5 percent.
Furthermore, the use of work practices (described below) by the best
performing facilities in the industry leads us to conclude that these
work practices are feasible, and accordingly, we are proposing a 5
percent opacity limit (based on 3-minute average) and work practices.
    Specifically, we are proposing that facilities will need to do the
following: (1) Keep all openings, except roof monitors (vents) and
other openings that are part of the designed ventilation of the
facility, closed during tapping and material transfer events (the only
openings that would be allowed during these events are the roof vents
and other openings or vents that are part of the designed ventilation
of the facility) to allow for more representative opacity observations
from a single opening; (2) have operators conduct regular inspections
of BOPF shop structure for unintended openings and leaks; (3) optimize
positioning of hot metal ladles with respect to hood face and furnace
mouth; (4) monitor opacity twice per month from all openings, or from
the one opening known to have the highest opacity, for a full steel
cycle, which must include a tapping event; and (5) develop and operate
according to an Operating Plan to minimize fugitives and detect
openings and leaks. We are proposing that the BOPF Shop Operating Plan
shall include:
    [ssquf] An explanation regarding how the facility will address and
implement the four specific work practices listed above;
    [ssquf] A maximum hot iron pour/charge rate (pounds/second) for the
first 20 seconds of hot metal charge (i.e., the process of adding hot
iron from the BF into the basic oxygen process furnace);
    [ssquf] A description of operational conditions of the furnace and
secondary emission capture system that must be met prior to hot metal
charge, including:
    [ssquf] A minimum flowrate of the secondary emission capture system
during hot metal charge;
    [ssquf] A minimum number of times, but at least once, the furnace
should be rocked between scrap charge and hot metal charge;
    [ssquf] A maximum furnace tilt angle during hot metal charging:
and;
    [ssquf] An outline of procedures to attempt to reduce slopping.
    We estimate the costs to implement these WPs will be about $500,000
per year for the source category ($60,000 per facility), and the WPs
will achieve about 25 tpy reduction in HAP metal emissions, with cost
effectiveness of $19,600 per ton HAP metals.
    We solicit comments and additional information regarding these
proposed requirements, including: (1) Comments regarding the specific
work practices and opacity limit, including the level of the opacity
limit, averaging time and frequency of the Method 9 opacity tests to
demonstrate compliance; (2) whether the EPA should only promulgate the
opacity limit and not include specific work practices; (3) whether the
EPA should only include the work practices and not the opacity limit;
(4) whether EPA should remove or change any of the specific work
practices described above, and if so, an explanation with supporting
analysis as to what changes should be made and why. We also are
soliciting comments on whether EPA should provide an alternative limit
to the 5 percent opacity limit for a small period of time during each
cycle, or for a certain time period (e.g., once per month or once per
3-month period), similar to the alternative standard that is in the
current subpart FFFFF NESHAP for new top blown BOPF shops, which says
that new top blown BOPF shops must not exceed an opacity of ``10
percent, except that one 3-minute period greater than 10 percent but
less than 20 percent may occur once per steel production.'' (See 40 CFR
part 63, subpart FFFFF), or whether EPA should make the standard, or
standards, also dependent on a percentage of operating time.
2. How did we develop the revised CAA section 112(d)(6) technology
standards for BF casthouse fugitive emissions?
    Fugitive emissions from the BF leave the casthouse through roof
vents, doors left open, and other openings. We estimate the current
total emissions from BF casthouses in the source category are about 46
tpy of HAP metals (such as manganese, arsenic, chromium and lead). The
current NESHAP includes 20 percent opacity limits for the casthouse.
Based on review of the CAA section 114 information request responses,
we determined that a 5 percent opacity limit is feasible and cost
effective. For example, based on recent 2022 data, two facilities
(Braddock and Gary) are already below 5 percent opacity (e.g., maximum
6-minute opacity readings of 3.54 and 4.17 percent, respectively).
Furthermore, based on thirteen Method 9 tests (each about 2 to 3.5
hours long) in 2018 to 2021 for casthouse fugitives at the Indiana
Harbor facility (which are available in the docket for this action),
the maximum 6-minute opacity from all of those tests was less than 2
percent opacity. Therefore, we have data indicating that at least three
facilities' BFs are already below 5 percent and therefore can meet the
proposed 5 percent opacity limit (based on 6-minute averages) with no
new control costs, and we expect the other 5 facilities can achieve 5
percent or lower opacity with cost-effective improvements in their
operations (as described in the technical memorandum cited below).
Therefore, we are proposing a 5 percent opacity limit (based on 6-
minute averages) as an update to the CAA section 112(d)(6) technology
review and proposing that facilities will need to measure opacity
during the tapping operations (at least 2 times per month). We are not
proposing specific work practices for the BF casthouse, except that we
are proposing that the facilities will need to keep all openings,
except roof monitors, closed during tapping and material transfer
events (the only openings that would be allowed during these events are
those that were present in the original design of the shop). We
estimate the costs to achieve and maintain the 5 percent opacity,
conduct and record the opacity readings, and ensure the openings
(described above) are closed will be approximately $740,000 per year
for the source category ($93,000 per facility). We estimate that these
actions would

achieve roughly 14.4 tpy reduction in emissions of HAP metals, with a
cost-effectiveness of about $51,400 per ton HAP metals. Additional
information regarding the emissions estimates and the cost calculations
for BOPF shop and casthouse is available in the following documents:
Unmeasured Fugitive and Intermittent Particulate Emissions and Cost
Impacts for Integrated Iron and Steel Facilities under 40 CFR part 63,
subpart FFFFF, which is available in the docket for this action.
    EPA solicits comments regarding any suggested modifications to the
BF casthouse proposed standards, with thorough explanations to support
any suggestions with regard to opacity limits and/or work practices
(and suggested regulatory text) including those described in an email
from Paul Balserak of the AISI and in an attachment to that email
titled: II&S DRAFT PROPOSED RULE UFIP LANGUAGE, February 22, 2023,
which are available in the docket for this action. However, we received
this information too late for us to be able to review and analyze for
this proposal. We solicit comments on the information that industry
representatives provided including whether EPA should adopt some or all
of these suggestions for the final rule, and a thorough explanation
including supporting analysis as to why, or why not. We also solicit
comments regarding whether EPA should provide an alternative to the 5
percent opacity limit for the BF casthouse, such as the potential
alternative described above for top blown BOPF shops opacity, or some
other type of alternative, and if so, an explanation of that possible
alternative and why, or whether EPA should make the standard, or
standards, also dependent on a percentage of operating time.
    A summary of estimated annual costs, HAP metal emission reductions,
and cost-effectiveness for the proposed standards of each UFIP source
are summarized in Table 3.

    Table 3--Estimated Annual Costs, HAP Metal Emission Reductions, and Cost-Effectiveness for Proposed UFIP
                                                    Standards
----------------------------------------------------------------------------------------------------------------
                                                         Annualized costs                              Cost-
                                                 --------------------------------    HAP metal     effectiveness
                     Source                          Total for      Average per      reduction      ($/ton HAP
                                                     industry        facility          (tpy)         removed)
----------------------------------------------------------------------------------------------------------------
BF Unplanned Openings...........................        $239,800         $30,000             0.5        $478,800
BF Planned Openings.............................          54,600           6,800            0.41         134,000
Slag Handling & Storage.........................         308,000          38,500             7.4          41,900
BF Bell Leaks...................................         935,000         120,000              31          30,000
BF Iron Beaching................................          55,000           6,800          0.0035      15,800,000
BOPF Shop Fugitives.............................         500,000          60,000              25          19,600
BF Casthouse Fugitives..........................         740,000          93,000            14.4          51,400
                                                 ---------------------------------------------------------------
    Total for the 7 UFIP sources................       2,828,200         353,500              79          35,924
----------------------------------------------------------------------------------------------------------------

C. Results of Fenceline Monitoring Data Analyses

    In the 2020 RTR, we identified arsenic and chromium as the HAP
metals driving the highest risk. Lead also had relatively high
emissions estimates in the RTR proposal and is a criteria air pollutant
with the potential to cause significant adverse health effects.
Therefore, with our 2022 CAA section 114 information requests, we
directed certain facilities to monitor these three HAP metals along
their fencelines using the sampling method described in 40 CFR part 50,
Appendix B. We requested fenceline data (i.e., measured concentrations
of the pollutant in the air at, or near, the fenceline in units of
micrograms per cubic meter of air ([micro]g/m\3\)) for arsenic,
chromium, and lead from four facilities at a minimum of four sampling
locations per facility (or a total of 16 monitoring sites for the
category) using Method 40 CFR part 50, appendix B. Each sampling period
lasted 24 hours with five-day intervals in between each sampling period
for a total of 6 months (i.e., facilities conducted air sampling for 24
hours every sixth day for a six-month period at each site). These
results were averaged at all sampling locations and periods for each
facility, resulting in a six-month average concentration for each metal
at each of the 16 fenceline locations.
1. Lead and Arsenic Results
    For lead, the highest measured 6-month average fenceline
concentration (from the 2022-2023 CAA section 114 request sampling) is
3 times greater than the highest modeled concentration for the example
facility (US Steel Gary) evaluated in the 2019 RTR proposed rule (84 FR
42704, August 16, 2019) and the 2020 RTR final rule (85 FR 42074, July
13, 2020).
    We compared the average 6-month fenceline measurements at each of
the 16 monitoring locations to the Pb National Ambient Air Quality
Standard (NAAQS), which is 0.15 [micro]g/m\3\ (based on a three-month
rolling average). For all locations at all facilities, the averages
were well below the NAAQS level, with the highest average only 20
percent of the NAAQS, indicating that lead concentrations are below
levels of concern at the fenceline for this source category.
    For arsenic, the average concentrations measured at the fencelines
of the four facilities ranged from 0.001 to 0.015 ug/m\3\. Compared to
the 2019-2020 modeled results, the highest measured fenceline
concentration for arsenic is 6 times higher than the highest modeled
concentration at the same example facility.
2. Chromium/Chromium VI Results
    Chromium concentrations measured at the fencelines of the four
facilities ranged from 0.001 to 0.175 ug/m\3\. Compared to the 2019-
2020 modeled results, the highest measured fenceline concentration of
Cr is 28 times higher than the highest modeled Cr concentration at the
same example facility.
    Chromium has the highest potential for adverse health effects when
it is in the chromium VI oxidized state (Cr\6+\), which is toxic and
classified as a human carcinogen; therefore, we estimated the
percentage of total chromium at the fenceline that is Cr\6+\. To do so,
we used a combination of previous emissions data from the emissions
release stacks from the 2020 RTR database and values provided by
industry--from ambient monitoring data from a site in Michigan that is
approximately 250 meters from the fenceline of an integrated iron and
steel facility--to determine a range of

ratios for Cr\6+\ to total Cr. The stack testing data from the EPA's
RTR proposed and final rules and the recent submittal from industry
regarding the ambient monitoring data are provided in the following
documents: Integrated Iron and Steel Risk and Technology Review: Point
Source Data Summary Memorandum (IIS_Data_Memo_05-01-19-PROPOSAL-
RTI.pdf) and DRAFT: Review of Available Hexavalent and Total Chromium
Ambient Monitoring Data (2022-12-16 427pm Draft--Review of Hex Chrome
to Chrome Ambient Air Data--Copy-c.pdf), which can be found in the
docket.
    The stack testing data collected from the 2011 Integrated Iron and
Steel Manufacturing Facilities CAA section 114 request to industry
provided ratios of 10 percent to 39 percent of total Cr that is Cr\6+\
for secondary and primary BOPF units, respectively. These data are
presented in the technical memorandum titled Integrated Iron and Steel
Risk and Technology Review: Point Source Data Summary, which is
available in the docket for the 2020 RTR final rule. Further inspection
into the data from this request revealed three issues with the values
of Cr\6+\ and total Cr, as follows: (1) Some values of Cr\6+\ were
higher than total Cr, which is scientifically impossible; (2) one value
of Cr\6+\ was equal to total Cr, which we expect is quite improbable
because only one value from one facility of the total 22 values from 11
facilities (provided in the 2020 document cited above) reported equal
results for Cr\6+\ and total chromium; and (3) there were a few
extremely high and low outliers. The data that fell under each of these
three categories were removed, and the ratio of Cr\6+\ to total Cr was
recalculated. This resulted in a new estimated range of ratios from 10
percent to 18 percent of the total Cr being in the Cr\6+\ form for
secondary and primary BOPF units, respectively.
    In addition, industry provided feedback on the original ratio range
of 10 percent to 39 percent Cr\6+\ with data supporting a much lower
ratio, around 1 percent. They provided ratios from ambient air data
collected from 2007-2012 at an EPA air toxics monitor approximately 250
meters from the Dearborn, MI Integrated Iron and Steel facility as well
as ratios from a Detroit Air Toxics Initiative (DATI) study in 2001 and
2006. The DATI study found ratios from 0.98 percent to 1.18 percent
Cr\6+\, while the Dearborn air monitoring analysis found ratios from
0.68 percent to 0.97 percent Cr\6+\. The DATI study and other Michigan
data mentioned above are available in the following document: 2022-12-
16 427pm Draft--Review of Hex Chrome to Chrome Ambient Air Data--Copy-
c.pdf, which is in the docket for this action.
    After considering all analysis, we concluded that an estimated
range for the ratio of Cr\6+\ to total Cr at the fenceline is 1 percent
to 18 percent and applied this range to the average total chromium
fenceline measurements to calculate lower- and upper-bound Cr\6+\
fenceline concentrations. The range of Cr\6+\ concentrations at the
fenceline across all four facilities using these ratios is 0.0001 to
0.0315 ug/m\3\. When compared to the 2020 modeled results, the highest
measured concentration of Cr\6+\ at the fenceline was anywhere from 2
to 32 times higher than the highest concentration modeled. This
indicates Cr and Cr\6+\ (using a ratio of 1 percent to 18 percent to
estimate measurements at the fenceline) emissions were underestimated
in the 2020 RTR risk modeling assessment. We expect this difference
between modeled and monitored levels is mainly due to an
underestimation of fugitive Cr emissions in the RTR.

D. What are the proposed decisions based on our fenceline monitoring
data analysis, and what is the rationale for those decisions?

    Based on our analysis of the available data and reductions we
expect would be achieved by the proposed work practices and opacity
limits described above in sections IV.A and B, we are proposing a
fenceline monitoring requirement in the NESHAP pursuant to CAA section
112(d)(6). Fenceline monitoring refers to the placement of monitors
along the perimeter of a facility to measure pollutant concentrations.
Coupled with requirements for root cause analysis and corrective action
upon triggering an actionable level, this work practice standard is a
development in practices considered under CAA section 112(d)(6) for the
purposes of managing fugitive emissions. The measurement of these
pollutant concentrations and comparison to concentrations estimated
from mass emissions via dispersion modeling can be used to ground-truth
emission estimates from a facility's emissions inventory. If
concentrations at the fenceline are greater than expected, the likely
cause is that there are underreported or unknown emission sources
affecting the monitors. In addition to the direct indication that
emissions may be higher than inventories would suggest, fenceline
monitoring provides information on the location of potential emissions
sources. Further, when used with a mitigation strategy, such as root
cause analysis and corrective action upon exceedance of an action
level, fenceline monitoring can be effective in reducing emissions and
reducing the uncertainty associated with emissions estimation and
characterization. Finally, public reporting of fenceline monitoring
data provides public transparency and greater visibility, leading to
more focus and effort in reducing emissions.
    Specifically, for the Integrated Iron and Steel Manufacturing
NESHAP, we are proposing that facilities must install four ambient air
monitors at or near the fenceline at appropriate locations around the
perimeter of the facility, regardless of facility size, based on a site
specific plan approved by the EPA and collect and analyze samples for
total chromium every sixth day, as well as implement the following work
practice requirement: if an installed fenceline monitor has a 12-month
rolling average delta c concentration, calculated as the annual average
of the highest sample value for a given sample period minus the lowest
sample value measured during that sample, that is above the proposed
action level of 0.1 [micro]g/m\3\ for total chromium, the facility must
conduct a root cause analysis and take corrective action to prevent
additional exceedances. Data will be reported electronically to the
EPA's Compliance and Emissions Data Reporting Interface (CEDRI) on a
quarterly basis and subsequently available to the public via the Web
Factor Information Retrieval system (WebFIRE) website. We solicit
comments regarding this proposed electronic reporting, specifically
whether when, when required, a corrective action plan should be
submitted via CEDRI and subsequently available through WebFIRE, subject
to CBI limitations.
    We chose to only propose fenceline measurements for chromium
because it is found to be a good surrogate for other HAP metals,
especially arsenic, which was the other risk driving HAP metal in the
2020 RTR risk analyses (as described in section IV.C of this preamble).
Arsenic values at the fenceline are found to correlate approximately
90% with chromium values at the fenceline according to linear
regression. Thus, the fenceline requirement for chromium will allow for
the effective management of fugitive emissions of other HAP metals.
    We derived the proposed action level of 0.1 [micro]g/m\3\ by first
evaluating all the fenceline Cr results to determine the highest
measured 6-month delta c average level across all facilities (which was
determined to be 0.154 [micro]g/m\3\ at the US Steel Gary facility).
The 2nd highest 6-month average monitoring delta c

result across all facilities was 0.115 [micro]g/m\3\ at the Granite
City facility. Both other facilities (Cleveland Works and Burns Harbor)
have delta c 6-month averages below 0.08 [micro]g/m\3\. To establish
the proposed action level, we evaluated the estimated reductions of HAP
metals that we expect will be achieved at Gary through the proposed
work practices and opacity limits. We estimate that the Gary facility
will achieve at least a 20 percent reduction in HAP metals by complying
with the proposed opacity limits and work practices. A 20 percent
reduction would result in an estimated highest 6-month delta c
concentration of about 0.123 [micro]g/m\3\. Because of the variability
and limitations in the data, to establish the proposed action level we
rounded off this highest 6-month value (i.e., 0.122) to one significant
figure (i.e., 0.1 [micro]g/m\3\). We determined that more significant
figures would not be appropriate based on such a data set. Therefore,
we are proposing 0.1 [micro]g/m\3\ as the action level for the
fenceline monitoring requirement. Given that: (1) Two of the four
facilities are already below 0.08 [micro]g/m\3\; (2) we project that
another facility (Granite City) will be below 0.1 after implementation
of the work practices and opacity limits; and (3) since the fourth
facility (Gary) is expected to have post control levels that are very
close to 0.1 [micro]g/m\3\ (and round-off to 0.1 [micro]g/m\3\) we
propose that an action level of 0.1 [micro]g/m\3\ is appropriate and
will ensure the effective management of fugitive emissions of other HAP
metals.
    We also considered a potential action level of 0.08 [micro]g/m\3\
or 0.09 [micro]g/m\3\ based in part on the following information. As
mentioned above, two of the four facilities already have 6-month delta
c averages below 0.08 [micro]g/m\3\ and one facility (Granite City) is
expected to be at 0.09 [micro]g/m\3\ after implementation of the work
practices and opacity limits. Furthermore, the fourth facility would
only need to achieve about a 42% reduction of UFIP emissions, therefore
we think an action level of 0.09 [micro]g/m\3\ (or some other level
such as 0.08 [micro]g/m3) might be appropriate and cost effective.
Therefore, we solicit comments and information as to whether an action
level of 0.09 [micro]g/m\3\ (or some other level such as 0.08 [micro]g/
m\3\) would be more appropriate than the proposed 0.1 [micro]g/m\3\
action level, and if so, why.
    Furthermore, we are proposing to also include a sunset provision
whereby if the 12-month average values remain 50 percent below (or
lower) than the action level (i.e., below 0.05 [micro]g/m\3\) for a 24-
month period, then that facility would not need to continue with
fenceline monitoring as long as they continue to comply with all other
proposed requirements described in this proposed rule along with all
other requirements already established in the current NESHAP. We
solicit comments regarding this proposed sunset provision, including
whether a reduced frequency of monitoring would be more appropriate
than a complete termination of such monitoring, and if so, what
frequency would be appropriate, or whether a reduced number of monitors
would be more appropriate (e.g., allow removal of each monitor that
remains below the 0.05 [micro]g/m\3\ for a period of time).
    More information regarding the estimated reductions of fugitive
emissions are provided in the document titled Unmeasurable Fugitive and
Intermittent Particulate Emissions and Cost Impacts for Integrated Iron
and Steel Facilities under 40 CFR part 63, subpart FFFFF, which is
available in the docket for this action.
    We expect that the proposed combination of work practices and
opacity limits described above in sections IV.A and B will likely
ensure fenceline concentrations remain below this action level most, if
not all, of the time, so we expect the only costs for this requirement
will be the costs for developing the plans, setting up monitoring
equipment, collecting and analyzing the samples, and reporting the
results. The estimated cost for this requirement is $25,000 capital
cost and $41,000/yr in annual costs per monitor, $100,000 capital costs
and $164,000/yr in annual costs per facility, and $800,000 capital
costs and $1.3M/yr in annual costs for the entire source category. This
includes equipment, installation, lab costs, and maintenance and labor.

E. Proposed Standards To Address Unregulated Point Sources for Both New
and Existing Sources

    In addition to the unregulated UFIP sources, we identified five
unregulated HAP from sinter plant point sources (CS2, COS,
HCl, HF, and Hg), three unregulated HAP (D/F, HCl and THC [as a
surrogate for organic HAP other than D/F]) from BF stove and BOPF point
sources, and two unregulated HAP (HCl and THC) from BF point sources.
    The proposed MACT limits for HCl and THC from BF stove point
sources were calculated based on data from nine runs each at two
different facilities. Six of these runs had no production data or lb/
ton emissions data in the test report. The lb/ton emissions values for
these six runs were calculated using the average of the BF stove
production values in the three test runs from the facility's 2012 HAP
metal emissions test report.
    The proposed MACT limit for THC from BOPF point sources were
calculated based on data from six runs at two different facilities.
Three of these runs had no production data or lb/ton emissions data in
the test report. The lb/ton emissions values for these three runs were
calculated using the average of the BOPF production values in the three
test runs from the facility's 2012 HAP metal emissions test report.
    We did not identify any cost-effective BTF options for these 13
unregulated HAP. The BTF options we considered and the estimated costs
and reductions that the BTF options would achieve are described in the
Maximum Achievable Control Technology Standard Calculations, Cost
Impacts, and Beyond-the-Floor Cost Impacts for Integrated Iron and
Steel Facilities under 40 CFR part 63, subpart FFFFF, which is
available in the docket for this action. Therefore, we are proposing
MACT floor limits for the five unregulated HAP from sinter plant point
sources, the three unregulated HAP from BF stove and BOPF point
sources, and the two unregulated HAP from BF casthouse control devices,
as shown in Table 4. We expect no control costs or emissions reductions
as a result of these emissions limits, except there will be some costs
for compliance testing, recordkeeping, and reporting which are
described in sections V.C and VIII.B of this preamble.
    As explained above, we are proposing MACT floor limits (not BTF
limits), so we think all facilities should be able to comply with these
MACT floor limits with their current controls (i.e., we expect there
will be no new control costs for the new MACT floor limits).
Nevertheless, EPA solicits comment regarding this conclusion.

                   Table 4--Estimated HAP Emissions and Proposed MACT Limits for Point Sources
----------------------------------------------------------------------------------------------------------------
                                                                Estimated source
              Process                          HAP             category emissions        Proposed MACT limit
----------------------------------------------------------------------------------------------------------------
Sinter Plants......................  CS2...................  23 tpy................  Existing and new sources:
                                                                                0.028 lb/ton sinter.
Sinter Plants......................  COS...................  72 tpy................  Existing sources: 0.064 lb/
                                                                                ton sinter.
                                                                                New sources: 0.030 lb/ton
                                                                                sinter.
Sinter Plants......................  HCl...................  12 tpy................  Existing sources: 0.025 lb/
                                                                                ton sinter.
                                                                                New sources: 0.0012 lb/ton
                                                                                sinter.
Sinter Plants......................  HF....................  1.3 tpy...............  Existing and new sources:
                                                                                0.0011 lb/ton sinter.
Sinter Plants......................  Hg....................  55 pounds/yr..........  Existing sources: 3.5e-5 lb/
                                                                                ton sinter.
                                                                                New sources: 1.2e-5 lb/ton
                                                                                sinter.
BF casthouse control devices.......  HCl...................  1.4 tpy...............  Existing sources: 0.0013 lb/
                                                                                ton iron.
                                                                                New sources: 5.9e-4 lb/ton
                                                                                iron.
BF casthouse control devices.......  THC...................  270 tpy...............  Existing sources: 0.092 lb/
                                                                                ton iron.
                                                                                New sources: 0.035 lb/ton
                                                                                iron.
BOPF...............................  D/F (TEQ\1\)..........  3.6 grams/yr..........  Existing and new sources:
                                                                                4.7e-8 lb/ton steel.
BOPF...............................  HCl...................  200 tpy...............  Existing sources: 0.078 lb/
                                                                                ton steel.
                                                                                New sources: 1.9e-4 lb/ton
                                                                                steel.
BOPF...............................  THC...................  13 tpy................  Existing sources: 0.04 lb/
                                                                                ton steel.
                                                                                New sources: 0.0017 lb/ton
                                                                                steel.
BF Stove...........................  D/F (TEQ).............  0.076 grams/year......  Existing and new sources:
                                                                                3.8e-10 lb/ton iron.
BF Stove...........................  HCl...................  4.5 tpy...............  Existing sources: 5.2e-4 lb/
                                                                                ton iron.
                                                                                New sources: 1.4e-4 lb/ton
                                                                                iron.
BF Stove...........................  THC...................  200 tpy...............  Existing sources: 0.1 lb/
                                                                                ton iron.
                                                                                New sources: 0.0011 lb/ton
                                                                                iron.
----------------------------------------------------------------------------------------------------------------
\1\ Toxic equivalents.

    The EPA solicits comment on the data used to calculate the MACT
floor limits (shown in Table 4). EPA also welcomes the submittal of
more test data from stakeholders, as soon as possible, to further
inform the development of appropriate MACT limits for the final rule.
We are also soliciting comments on whether the format of the limits
(lbs/ton) for BF Stoves is most appropriate or whether a different
format would be more appropriate for the BF Stoves such as lbs of HAP
per cubic foot of gas or lbs of HAP per British thermal unit (BTU). EPA
also solicits comment on whether an averaging compliance alternative
should be considered for the NESHAP to demonstrate compliance with the
limits and if so what types of alternatives should be considered. We
also solicit comment on whether there are surrogates that are
representative of any of the new HAP limits that EPA should consider
and, if so, why, including an explanation as to how that surrogate
might be appropriate for any of these HAP.

F. Reconsideration of Standards for D/F and PAH for Sinter Plants Under
CAA Section 112(d)(6) Technology Review for Both New and Existing
Sources

    As part of our updates to the CAA section 112(d)(6) review, we
analyzed available test data for D/F and PAH from sinter plants. We
also evaluated potential emissions limits for D/F and PAHs. First, we
developed a regulatory option that reflects the current control
technologies and practices (current performance) at the existing sinter
plants at the three source category facilities that have sinter plants.
The sinter plants are currently controlled with baghouses or wet
scrubbers. To derive an emissions limit that reflects current controls,
we used the UPL approach we typically use for calculation of MACT floor
limits (described above in section III.B). Using the UPL method, we
calculated an emissions limit of 3.5E-08 lbs/ton of sinter for D/F
(TEQ) and an emissions limit of 5.9E-03 lbs/ton for PAHs for existing
sinter plant windboxes and limits of 3.1E-09 lbs/ton of sinter for D/F
(TEQ) and 1.5E-03 lbs/ton of sinter for PAHs for new sinter plant
windboxes.
    Second, as part of the technology review, we analyzed and evaluated
an option based on the addition of new controls (i.e., activated carbon
injection or ACI) to reduce emissions of D/F and PAHs. We estimate the
total capital costs of these controls would be $950,000, the annual
costs would be $2.3 million, and the controls would achieve 8 grams per
year reduction of D/F TEQ and 5.4 tpy reduction of PAHs, with cost
effectiveness of $287,000 per gram and $340,000 per ton, respectively.
    Based on that analysis and evaluation of regulatory options, we
conclude that the second option (i.e., addition of ACI) is not cost
effective. This conclusion is consistent with the EPA's decisions made
in the 2020 RTR final rule as part of our ample margin of safety
analysis for D/F in 2020. Therefore, we are proposing the emissions
limits of 3.5E-08 lbs/ton of sinter for D/F (TEQ) and 5.9E-03 lbs/ton
of sinter for PAHs for existing sinter plant windboxes, and limits of
3.1E-09 lbs/ton of sinter for D/F (TEQ) and 1.5E-03 lbs/ton of sinter
for PAHs for new sinter plant windboxes that reflect current
performance. We estimate all three facilities with sinter plants would
be able to meet these limits with no additional controls so there will
be no emissions reductions with these new existing standards. The
estimated costs for compliance tests are $50,000 to $75,000 per
facility, once every 5 years. Furthermore, we do not expect any new
sinter plants will be constructed in the foreseeable future. Therefore,
we expect no impacts due to these new source emissions limits.
    Regarding the second option described above (i.e., an emissions
limit based on addition of ACI), although we are not proposing this
option, we solicit comments regarding this option, including the cost
effectiveness determination and whether or not EPA should establish a
tighter limit (based on application of ACI) and if so why and analysis
to support that conclusion. For more details regarding our data and
analyses of options, see the technical memorandum titled: Maximum
Achievable Control Technology Standard Calculations, Cost Impacts, and
Beyond-the-Floor Cost Impacts for Integrated Iron and Steel Facilities
under 40 CFR part 63, subpart FFFFF, which is available in the docket
for this action.
    EPA also solicits comment on whether the proposed new limits for
dioxin/furans and PAHs are appropriate

or if EPA should instead maintain the current approach in the NESHAP
which is that the sinter plant oil content limit of the feedstock to
the sinter plant and/or the VOC emission limit from the windbox exhaust
stream are surrogates for the dioxin/furans and PAH emissions for
sinter plants.

G. Adding 1-Bromopropane to List of HAP

    On January 5, 2022, the EPA published a final rule amending the
list of hazardous air pollutants (HAP) under the CAA to add 1-
bromopropane (1-BP) in response to public petitions previously granted
by the EPA. (87 FR 393). Consequently, as each NESHAP is reviewed, we
are evaluating whether the addition of 1-BP to the CAA section 112 HAP
list impacts the source category. For the Integrated Iron and Steel
Manufacturing Facilities source category, we conclude that the
inclusion of 1-BP as a regulated HAP would not impact the
representativeness of the MACT standard because, based on available
information, we have no evidence that 1-BP is emitted from this source
category. As a result, no changes are being proposed to the subpart
FFFFF NESHAP based on the January 2022 rule adding 1-BP to the list of
HAP. Nevertheless, we are requesting comments regarding the use of 1-BP
and any potential emissions of 1-BP from this source category.

H. What compliance dates are we proposing?

    Amendments to the Integrated Iron and Steel Manufacturing
Facilities NESHAP proposed in this rulemaking for adoption under CAA
section 112(d)(2), (3), and (6) and 112(h) are subject to the
compliance deadlines outlined in the CAA under section 112(i). For
existing sources, CAA section 112(i)(3) provides there shall be
compliance ``as expeditiously as practicable, but in no event later
than 3 years after the effective date of such standard . . . .''
subject to certain exemptions further detailed in the statute.\5\ In
determining what compliance period is as ``expeditious as
practicable,'' we consider the amount of time needed to plan and
construct projects and change operating procedures. As provided in CAA
section 112(i), all new affected sources must comply with these
provisions by the effective date of the final amendments to the
Integrated Iron and Steel Manufacturing Facilities NESHAP or upon
startup, whichever is later.
---------------------------------------------------------------------------

    \5\ Ass'n of Battery Recyclers v. EPA, 716 F.3d 667, 672 (D.C.
Cir. 2013) (stating that ``section 112(i)(3)'s 3-year maximum
compliance period applies generally to `any emission standard . . .
promulgated under [CAA section 112]''' (quoting 42 U.S.C. 7412(i)(3)
(brackets in original)).
---------------------------------------------------------------------------

    All affected facilities would have to continue to meet the current
provisions of 40 CFR part 63, subpart FFFFF until the applicable
compliance date of the amended rule. The final action is expected to
qualify under the definition in 5 U.S.C. 804(2), so the effective date
of the final rule will be 60 days after the promulgation date as
specified in the Congressional Review Act. See 5 U.S.C. 801(a)(3)(A).
    With regard to the new emissions limits for sinter plant windboxes,
since we have test data from all three existing sinter plants except
for HF from one facility, and because these facilities already have
controls in place to meet the new emissions limits (as described
above), we expect facilities will be able to comply with the new
emissions limits in a relatively short time period after the final rule
is published in the Federal Register. However, we expect the sources
will need some time (e.g., up to 6 months) to conduct applicability
reviews, conduct performance testing, and implement monitoring to
comply with the new emissions limits. Therefore, for all affected
sinter plant windbox sources that commence construction or
reconstruction on or before July 31, 2023, we are proposing that owners
or operators must comply with the new emissions limits within 6 months
after the promulgation date of the final rule.
    With regard to fenceline monitoring requirements, a method for the
fenceline measurement of metals has not yet been promulgated. Once the
method is promulgated, we expect that sources will need up to 6 months
to begin the required monitoring because they first need to develop
fenceline monitoring plans, submit those plans to the EPA for review
and approval, and then they will require time to set up all the
fenceline monitors which will include, in some cases, installing new
electric powerlines to support the new monitors. Therefore, for all
affected sources that commence construction or reconstruction on or
before July 31, 2023, we are proposing that owners or operators must
comply with the proposed fenceline monitoring requirements within 1
year of promulgation of the fenceline method for metals or 2 years
after the promulgation date of the final rule, whichever is later. This
would mean that facilities would need to begin the fenceline monitoring
no later than 1 year after the promulgation date of the fenceline
method or 2 years after promulgation of the rule. The EPA intends to
propose a metals fenceline method sometime in 2024 through a separate
action. Subsequently, the proposed action level and requirements for
root cause analyses and other actions would apply 12 months later since
the action level is based on 12-month rolling average concentrations.
    With regard to the proposed opacity limits and work practice
standards, although we do not expect the need for any additional add-on
controls, we expect facilities need up to 12 months to install and
operate various types of equipment, such as devices to continuously
measure/monitor material levels in BFs with alarms to inform operators
of static conditions which increase likelihood of unplanned bleeder
valve openings; instruments on the BF to monitor temperature and
pressure; water spray equipment or fogging equipment to minimize
emissions from slag; full or partial enclosures or CO2 gas
suppression equipment to minimize emissions during beaching; improved
hooding or fans to increase draft velocities to capture more fugitives
in BF casthouse or BOPF shop; or improved runner covers in the BF
casthouses. Furthermore, facilities may need several months to repair
unintended openings in the BF casthouse or BOPF shop that are not part
of the original or modified building design. Therefore, for all
affected sources that commence construction or reconstruction on or
before July 31, 2023, we are proposing that owners or operators must
comply with the opacity limits and work practices for the seven UFIP
sources described above in sections IV.A and B within 12 months after
promulgation.
    With regard to the new emissions limits for HCl, THC, and D/F for
BFs and BOPFs, as explained above in section IV.E, we expect all
facilities will be able to comply with the new emissions limits without
the need for additional controls because all BFs and BOPFs are similar
and have similar controls. Therefore, for all affected BF and BOPF
sources that commence construction or reconstruction on or before July
31, 2023, we are proposing that owners or operators must comply within
6 months after the promulgation date of the final rule.
    For all affected sources that commence construction or
reconstruction after July 31, 2023, we are proposing that owners or
operators must comply with the all the proposed new and revised
provisions by the

effective date of the final rule (or upon startup, whichever is later).
All compliance dates for this proposed rule are summarized in Table 5.

       Table 5--Summary of Compliance Dates for the Proposed Rule
------------------------------------------------------------------------
            Source(s)              Rule requirement     Compliance date
------------------------------------------------------------------------
All affected sinter plant         Proposed new        6 months after the
 windbox sources that commence     emissions limits    promulgation date
 construction or reconstruction    for mercury, HCl,   of the final
 on or before July 31, 2023.       HF, CS2, COS, D/    rule.
                                   F, and PAH.
All affected sources that         Proposed fenceline  1 year after the
 commence construction or          monitoring          promulgation of
 reconstruction on or before       requirements.       the fenceline
 July 31, 2023.                                        method for metals
                                                       or 2 years after
                                                       the promulgation
                                                       date of the final
                                                       rule, whichever
                                                       is later.
                                  Proposed opacity    12 months after
                                   limits and work     the promulgation
                                   practices for the   date of the final
                                   seven UFIP          rule.
                                   sources.
All affected BF and BOPF sources  Proposed new        6 months after the
 that commence construction or     emissions limits    promulgation date
 reconstruction on or before       for HCl, THC, and   of the final
 July 31, 2023.                    D/F.                rule.
All affected sources that         All proposed new    Effective date of