Document ID: EPA-HQ-OAR-2017-0664-0181
Agency: epa
Document Type: Proposed Rule
Title: National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing Amendments
Posted Date: 2023-05-15T04:00Z

[Federal Register Volume 88, Number 93 (Monday, May 15, 2023)]
[Proposed Rules]
[Pages 30917-30934]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-10068]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2017-0664; FRL-5925.1-01-OAR]
RIN 2060-AV58

National Emission Standards for Hazardous Air Pollutants: 
Taconite Iron Ore Processing Amendments

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 Taconite Iron Ore Processing Plants, as 
required by the Clean Air Act (CAA). To ensure that all emissions of 
hazardous air pollutants (HAP) from sources in the source category are 
regulated, the EPA is proposing emission standards for mercury. In 
addition, the EPA is proposing to revise the existing emission 
standards for hydrogen chloride and hydrogen fluoride.

DATES: 
    Comments. Comments must be received on or before June 29, 2023. 
Under the Paperwork Reduction Act (PRA), comments on the information 
collection provisions are best assured of consideration if the Office 
of

[[Page 30918]]

Management and Budget (OMB) receives a copy of your comments on or 
before June 14, 2023.
    Public hearing: If anyone contacts us requesting a public hearing 
on or before May 22, 2023, we will hold a virtual public hearing. See 
SUPPLEMENTARY INFORMATION for information on requesting and registering 
for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2017-0664, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2017-0664 in the subject line of the message.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2017-0664, 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 David Putney, 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: (919) 541-2016; email address: 
[email protected].

SUPPLEMENTARY INFORMATION: 
    Participation in virtual public hearing. To request a virtual 
public hearing, contact the public hearing team at (888) 372-8699 or by 
email at [email protected]. If requested, the hearing will be 
held via virtual platform on May 30, 2023. The hearing will convene at 
10 a.m. Eastern Time (ET) and will conclude at 4 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/taconite-iron-ore-processing-national-emission-standards-hazardous.
    If a public hearing is requested, the EPA will begin 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/taconite-iron-ore-processing-national-emission-standards-hazardous 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 May 30, 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/taconite-iron-ore-processing-national-emission-standards-hazardous.
    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/taconite-iron-ore-processing-national-emission-standards-hazardous. While the EPA expects the hearing to go forward as set forth 
above, please monitor our website or contact the public hearing team at 
(888) 372-8699 or by email at [email protected] to determine if 
there are any updates. The EPA does not intend to publish a document in 
the Federal Register announcing updates.
    If you require the services of a translator or special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team and describe your needs by May 22, 
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-2017-0664. 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-
2017-0664. 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

[[Page 30919]]

and included as part of the comment that is placed in the public docket 
and made available on the internet. If you submit an electronic 
comment, the EPA recommends that you include your name and other 
contact information in the body of your comment and with any digital 
storage media you submit. If the EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, the 
EPA may not be able to consider your comment. Electronic files should 
not include special characters or any form of encryption and be free of 
any defects or viruses. For additional information about the EPA's 
public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov/. Clearly mark the part or all of 
the information that you claim to be CBI. For CBI information on any 
digital storage media that you mail to the EPA, note the docket ID, 
mark the outside of the digital storage media as CBI, and identify 
electronically within the digital storage media the specific 
information that is claimed as CBI. In addition to one complete version 
of the comments that includes information claimed as CBI, you must 
submit a copy of the comments that does not contain the information 
claimed as CBI directly to the public docket through the procedures 
outlined in Instructions above. If you submit any digital storage media 
that does not contain CBI, mark the outside of the digital storage 
media clearly that it does not contain CBI and note the docket ID. 
Information not marked as CBI will be included in the public docket and 
the EPA's electronic public docket without prior notice. Information 
marked as CBI will not be disclosed except in accordance with 
procedures set forth in 40 Code of Federal Regulations (CFR) part 2.
    Our preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol (FTP), 
or other online file sharing services (e.g., Dropbox, OneDrive, Google 
Drive). Electronic submissions must be transmitted directly to the 
Office of Air Quality Planning and Standards (OAQPS) CBI Office at the 
email address [email protected], and 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-2017-0664. 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
BTF beyond-the-floor
CAA Clean Air Act
CBI Confidential Business Information
CFR Code of Federal Regulations
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
ESP electrostatic precipitator
FR Federal Register
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
km kilometer
lb/LT pounds of mercury emitted per long ton of pellets produced
MACT maximum achievable control technology
MIR maximum individual risk
NAICS North American Industry Classification System
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
PM particulate matter
PRA Paperwork Reduction Act
RDL representative detection level
REL reference exposure level
RFA Regulatory Flexibility Act
RTR residual risk and technology review
SBA Small Business Administration
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology. Fate, Transport, and 
Ecological Exposure model
UF uncertainty factor
UPL upper prediction limit
[mu]g/m3 microgram per cubic meter
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
VCS voluntary consensus standards

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
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 did we address unregulated pollutants?
    B. How did we perform the technology review?
IV. Analytical Results and Proposed Decisions
    A. What are the results of our analyses of unregulated 
pollutants and how did we establish the proposed MACT standards?
    B. What are the results of our technology review and what 
revisions to the MACT standards are we proposing?
    C. What performance testing are we proposing?
    D. What operating limits and monitoring requirements are we 
proposing?
    E. What recordkeeping and reporting requirements are we 
proposing?
    F. What are the results of any risk analyses completed for this 
action?
    G. What other actions are we proposing?
    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 analysis of environmental justice did we conduct?
    F. What analysis of children's environmental health did we 
conduct?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 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

[[Page 30920]]

Minority Populations and Low-Income Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 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 
Taconite Iron Ore Processing source category includes any facility 
engaged in separating and concentrating iron ore from taconite, a low-
grade iron ore to produce taconite pellets. The source category 
includes, but is not limited to, the following processes: liberation of 
the iron ore by wet or dry crushing and grinding in gyratory crushers, 
cone crushers, rod mills, and ball mills; pelletizing by wet tumbling 
with a balling drum or balling disc; induration using a straight grate 
or grate kiln indurating furnace; and finished pellet handling.

 Table 1--NESHAP and Source Categories Affected by This Proposed Action
------------------------------------------------------------------------
         Source category                  NESHAP          NAICS code \1\
------------------------------------------------------------------------
Taconite Iron Ore Processing.....  40 CFR part 63,                21221
                                    subpart RRRRR.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

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

    In addition to being available in the docket, an electronic copy of 
this 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/taconite-iron-ore-processing-national-emission-standards-hazardous. 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. 
Information on the overall residual risk and technology review (RTR) 
program is available at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A memorandum showing the rule edits that would be necessary to 
incorporate the changes to 40 CFR part 63, subpart RRRRR proposed in 
this action is available in the docket (Docket ID No. EPA-HQ-OAR-2017-
0664). Following signature by the EPA Administrator, the EPA also will 
post a copy of this document to https://www.epa.gov/stationary-sources-air-pollution/taconite-iron-ore-processing-national-emission-standards-hazardous.

II. Background

A. What is the statutory authority for this action?

    This action proposes to amend the NESHAP for Taconite Iron Ore 
Processing, which was previously amended when the EPA finalized the 
Residual Risk and Technology Review for this source category on July 
28, 2020.\1\
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    \1\ 85 FR 45476; July 28, 2020.
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    In the Louisiana Environmental Action Network v. EPA (LEAN) 
decision issued on April 21, 2020, the U.S. Court of Appeals for the 
District of Columbia Circuit (D.C. Circuit) held that the EPA has an 
obligation to address unregulated emissions from a major source 
category when the Agency conducts the 8-year technology review required 
by CAA section 112(d)(6).\2\ This proposed rule addresses currently 
unregulated emissions of HAP from the Taconite Iron Ore Processing 
source category. Emissions data collected from the exhaust stacks of 
existing taconite indurating furnaces indicate that mercury (Hg) is 
emitted from the source category. However, mercury emissions from the 
Taconite Iron Ore Processing source category are not regulated under 
the existing Taconite Iron Ore Processing NESHAP. Therefore, the EPA is 
proposing new standards that reflect MACT for mercury emitted from 
taconite indurating furnaces, pursuant to CAA sections 112(d)(2) and 
(3). We are also proposing to modify the existing emissions standards 
for hydrochloric acid (HCl) and hydrofluoric acid (HF) pursuant to CAA 
section 112(d)(6). CAA section 112(d)(6) separately 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 8 years. Based on 
new information, we are proposing to revise the technology review 
completed in 2020 by proposing revised HCl and HF standards at this 
time.
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    \2\ Louisiana Environmental Action Network (LEAN) v. EPA, 955 
F.3d 1088 (D.C. Cir. 2020).
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B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?

    The NESHAP for Taconite Iron Ore Processing (codified at 40 CFR 
part 63, subpart RRRRR) regulates HAP emissions from new and existing 
taconite iron ore processing plants that are major sources of HAP. 
Taconite iron ore processing plants separate and concentrate iron ore 
from taconite, a low-grade iron ore containing 20- to 25-percent iron, 
and produce taconite pellets, which are 60- to 65-percent iron. 
Taconite iron ore processing includes crushing and handling of the 
crude ore, indurating, and finished pellet handling.
    The Taconite Iron Ore Processing NESHAP applies to each new or 
existing ore crushing and handling operation, ore dryer, pellet 
indurating furnace, and finished pellet handling operation at a 
taconite iron ore processing plant that is (or is part of) a major 
source of HAP emissions. There are currently eight taconite iron ore 
processing plants in the United States: six facilities are located in 
Minnesota and two are located in Michigan. While the Empire Mining 
facility in Michigan maintains an air quality permit to operate, the 
facility has been indefinitely idled since 2016. Therefore, the Empire 
Mining facility is not included in any analyses (e.g., expected 
emissions, estimated cost impacts, estimated emission reductions) 
associated with this proposed rulemaking. A different taconite 
facility, the Northshore Mining facility located in Minnesota, has been 
temporarily idled since 2022, but is expected to resume operations as 
early as Spring 2023. Therefore, we included the

[[Page 30921]]

Northshore Mining facility in the analyses conducted for this 
rulemaking.
    Indurating furnaces represent the most significant source of HAP 
emissions from the Taconite Iron Ore Processing source category. The 
indurating furnaces are responsible for approximately 99 percent of 
total HAP emissions from this source category. Indurating furnaces emit 
acid gases, mercury and other metal HAP (e.g., arsenic, chromium, 
nickel) that are present in the taconite ore and sometimes in the fuel 
(such as coal) fed into the furnaces, and small amounts of organic HAP 
(e.g., formaldehyde). The acid gases include HCl and HF and are formed 
when chlorine and fluorine compounds are released from the raw 
materials during the indurating process and combine with moisture in 
the exhaust stream.
    The existing emission limits consist of particulate matter (PM) 
limits, which serve as a surrogate for particulate metal HAP emissions; 
PM also serves as a surrogate for HCl and HF. Table 2 lists the 
emission standards that currently apply to taconite iron ore processing 
facilities subject to 40 CFR part 63, subpart RRRRR. The current NESHAP 
also includes work practice standards to address organic HAP emissions 
and fugitive emissions.

     Table 2--Current PM Standards for Taconite Iron Ore Processing
------------------------------------------------------------------------
                                                            PM emission
          Affected source            Affected source is     limits (gr/
                                       new or existing       dscf) \1\
------------------------------------------------------------------------
Ore crushing and handling emission  Existing............           0.008
 units.
                                    New.................           0.005
Straight grate indurating furnace   Existing............            0.01
 processing magnetite.
                                    New.................           0.006
Grate kiln indurating furnace       Existing............            0.01
 processing magnetite.
                                    New.................           0.006
Grate kiln indurating furnace       Existing............            0.03
 processing hematite.
                                    New.................           0.018
Finished pellet handling emission   Existing............           0.008
 units.
                                    New.................           0.005
Ore dryer.........................  Existing............           0.052
                                    New.................           0.025
------------------------------------------------------------------------
\1\ gr/dscf = grains per dry standard cubic foot.

    The taconite iron ore processing NESHAP also regulates fugitive 
emissions from stockpiles (including uncrushed and crushed ore and 
finished pellets), material transfer points, plant roadways, tailings 
basins, pellet loading areas, and yard areas. Fugitive emissions must 
be controlled using the work practices specified in a facility's 
fugitive dust emissions control plan.
    The EPA previously conducted a residual risk and a technology 
review pursuant to CAA sections 112(f)(2) and 112(d)(6), respectively 
(Docket Item No. EPA-HQ-OAR-2017-0664-0164). The EPA published the RTR 
proposed rule on September 25, 2019 (84 FR 50660), and the RTR final 
rule on July 28, 2020 (85 FR 45476). In the final rule, the EPA 
concluded that the risks associated with HAP emissions from taconite 
iron ore processing were acceptable and that the current NESHAP 
provides an ample margin of safety to protect public health. In the 
2020 final rule, the EPA concluded that there were no developments in 
practices, processes, or control technologies that would warrant 
revisions to the standards. Therefore, no changes were made to the 
emissions standards as part of that action. However, the 2020 
rulemaking removed the exemptions for periods of startup, shutdown, and 
malfunction (SSM), included provisions requiring electronic reporting, 
and made some other minor changes to the NESHAP.

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

    Prior to developing the initial MACT standards for the Taconite 
Iron Ore Processing source category, which were finalized in 2003 (68 
FR 61868; October 30, 2003), the EPA collected information on the 
emissions, operations, and location of taconite iron ore processing 
facilities. To inform the development of the 2019 RTR proposed rule, we 
obtained data from the EPA's 2014 National Emissions Inventory (NEI) 
database (https://www.epa.gov/air-emissions-inventories/2014-national-emissions-inventory-nei-data) and supplemental information submitted by 
industry. Data on the numbers, types, dimensions, and locations of the 
emission points for each facility were obtained from the NEI, state 
agencies, Google EarthTM, and taconite iron ore processing 
industry staff. To inform this current action, in 2022, pursuant to CAA 
section 114, the EPA sent an information request (hereinafter ``2022 
CAA section 114 information request'') to seven facilities in the 
source category to obtain updated information about taconite iron ore 
processing facilities. (The EPA did not send an information request to 
the Empire Mining facility since, as discussed in section II.B of this 
preamble, above, that facility has been indefinitely idled since 2016.) 
The 2022 CAA section 114 information request consisted of a 
questionnaire and stack testing requirements. The questionnaire was 
used to collect information on the location and number of indurating 
furnaces, production throughput, types of pellets produced, types and 
quantities of fuels burned, information on air pollution control 
devices and emission points, historical test data, and other 
documentation (e.g., title V permits). Two companies (U.S. Steel 
Corporation and Cleveland-Cliffs Incorporated) completed the 
questionnaire for which they reported data for seven major source 
facilities.\3\
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    \3\ As discussed in section II.B, this does not include the 
Empire Mining facility, which has been indefinitely idled since 
2016.
---------------------------------------------------------------------------

    In addition to the questionnaire, the EPA required each taconite 
iron ore processing facility, with the exception of the Empire Mining 
facility, to complete stack testing of one or more representative 
indurating furnaces for the following pollutants: filterable PM, metal 
HAP, and the acid gases HCl and HF.\4\ EPA Method 5 was used to measure 
filterable PM, EPA Method 29 was used to measure metal HAP emissions, 
and EPA Method 26A was

[[Page 30922]]

used to measure HCl and HF emissions. Six facilities completed the 
required stack testing and submitted emissions data for a total of 
seven indurating furnaces.\5\
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    \4\ The EPA did not require the Empire Mining facility to submit 
stack testing because the facility has been indefinitely idled since 
2016.
    \5\ The EPA initially planned to require the Northshore Mining 
facility to conduct stack testing. However, the facility's 
indurating furnaces were idled during the period of the information 
collection and are not expected to return to operation until at 
least spring 2023. As a result, we ultimately did not require the 
Northshore Mining facility to complete stack testing within the 
timeframe available before the Administrator's signature of this 
proposed rule.
---------------------------------------------------------------------------

    In this action, the EPA used the emissions data collected from the 
2022 CAA section 114 information request, as well as results from 
previous stack tests completed from 2014 through 2021 to develop 
proposed MACT standards for mercury, pursuant to CAA sections 112(d)(2) 
and (3).\6\ We also used the emissions data for HCl and HF collected 
from the 2022 CAA section 114 information request to inform proposed 
revisions to the existing emissions standards for these acid gases, 
pursuant to CAA section 112(d)(6). The data collected and considered 
are available in the docket for this action. In addition, the data 
collection and analyses for this action are described in detail in two 
documents, Maximum Achievable Control Technology (MACT) Analysis for 
Proposed Mercury Standards for Taconite Iron Ore Indurating Furnaces 
and Revised Technology Review of Acid Gas Controls for Indurating 
Furnaces in the Taconite Iron Ore Processing Source Category, both of 
which are available in the docket for this action (Docket ID No. EPA-
HQ-OAR-2017-0664).
---------------------------------------------------------------------------

    \6\ Due to the relative scarcity of stack test data available 
from the taconite iron ore processing facilities, additional mercury 
emissions data from testing performed from 2014 through 2021 at 
facilities listed in the 2022 CAA section 114 information request 
were also used in development of the MACT standards for mercury. 
This testing was performed under similar conditions and testing 
methodologies that were requested in the 2022 CAA section 114 
information request.
---------------------------------------------------------------------------

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

    In addition to the 2022 CAA section 114 information request 
discussed in section II.C. of this preamble, the EPA also reviewed the 
information sources listed below to help inform the development of the 
proposed MACT standards for mercury and to determine whether there have 
been developments in practices, processes, or control technologies for 
taconite iron ore processing facilities pursuant to CAA section 
112(d)(6). These additional information sources include the following:
     Emissions tests and reports for testing completed between 
2014 and 2021 on 11 indurating furnaces located at six plants in 
Minnesota. Stack tests on nine furnaces used EPA Method 29 to measure 
mercury emissions, stack tests on three furnaces used the Ontario Hydro 
method (ASTM D6784-16), and stack tests on one furnace used EPA Method 
29 and the Ontario Hydro method.
     Data on the variation of the concentration of mercury in 
the ore from the mines used by taconite iron ore processing facilities 
provided by industry and the American Iron and Steel Institute (the 
industry association representing the industry in the affected NAICS 
category and their members).
     Site-specific Mercury Reduction Plans and mercury control 
technology evaluations required by Minnesota state regulations.\7\ 
These documents include Mercury Reduction Plans for Northshore Mining 
Company in Silver Bay, Minnesota and Minorca Mine, Inc. in Virginia, 
Minnesota; and technology evaluations for the following four plants: 
Hibbing Taconite Company in Hibbing Minnesota; United Taconite LLC in 
Forbes Minnesota, U.S. Steel--Minntac in Mountain Iron, Minnesota and 
U.S. Steel--Keetac in Keewatin, Minnesota.
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    \7\ The Mercury Reduction Plans and mercury control technology 
evaluations were submitted to the Minnesota Pollution Control Agency 
(MPCA) in 2018 in response to a Minnesota regulation (see Minn. R. 
7007.0502) requiring mercury emission reductions of 72 percent from 
2008 or 2010 emission levels by January 1, 2025. The regulation 
requires a mercury reduction plan for sources that emit more than 3 
pounds of mercury (or 5 pounds for industrial boilers). We also 
considered the MPCA responses to the industry submittals.
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    Copies of these materials are available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2017-0664).

III. Analytical Procedures and Decision-Making

    In this section, we describe the analyses performed to support the 
proposed decisions for the issues addressed in this proposal.

A. How did we address unregulated pollutants?

    In evaluating the Taconite Iron Ore Processing source category and 
emissions data collected in support of the 2020 RTR and through the 
2022 CAA section 114 information request, we identified mercury as a 
HAP emitted from facilities in the source category. Mercury, which is 
emitted primarily in a gaseous form (not as a particle), is not 
regulated under the existing standards for the source category. 
Emissions data from stack tests conducted since 2014 indicate mercury 
is emitted by indurating furnaces at taconite iron ore processing 
facilities. Mercury was the only HAP identified by the EPA that is not 
regulated under the existing standards for this source category. The 
EPA has a ``clear statutory obligation to set emissions standards for 
each listed HAP'' emitted from a source category.\8\ In this action, we 
are proposing emissions limits for mercury pursuant to CAA sections 
112(d)(2) and (3) for new and existing indurating furnaces.
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    \8\ National Lime v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000).
---------------------------------------------------------------------------

    Pursuant to CAA section 112(d)(3), since there are fewer than 30 
sources in the category, the minimum standards for existing sources are 
calculated based on the average performance of the best-performing five 
sources in the source category, taking into consideration the 
variability of HAP emissions from the emission sources. This is 
commonly referred to as the ``MACT floor.'' The MACT floor for new 
sources is based on the single best-performing source, with a similar 
consideration of variability in emissions from the best-performing 
source. 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 mercury 
emissions from indurating furnaces, we calculated the MACT floors using 
the 99-percent Upper Prediction Limit (UPL) approach from the stack 
test data collected for the 2022 CAA section 114 information request 
and data from the stack tests completed on indurating furnaces from 
2014 through 2021.
    The UPL approach addresses variability of emissions 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 memorandum Use of 
Upper Prediction Limit for Calculating MACT Floors which is available 
in the docket for this action (Docket ID No. EPA-HQ-OAR-2017-0664), the 
EPA uses the UPL approach to reasonably estimate the emissions 
performance of the best-performing source or sources to establish MACT 
floor standards.
    In addition to calculating the MACT floor, the EPA must examine 
more stringent ``beyond-the-floor'' (BTF) regulatory options to 
determine MACT.

[[Page 30923]]

Unlike the MACT floor's minimum stringency requirements, the EPA must 
consider various impacts of the more stringent regulatory options in 
determining whether the proposed MACT standards should reflect beyond-
the-floor requirements. If the EPA concludes that the more stringent 
regulatory options have unreasonable cost, non-air quality health and 
environmental, and/or energy impacts, the EPA selects the MACT floor as 
MACT. However, if the EPA concludes that impacts associated with BTF 
levels of control are reasonable in light of additional emissions 
reductions achieved, the EPA selects those BTF levels of control as 
MACT.
    The methodology used to develop the new mercury standards is 
described in detail in the document, Maximum Achievable Control 
Technology (MACT) Analysis for Proposed Mercury Standards for Taconite 
Iron Ore Indurating Furnaces, located in the docket for this action 
(Docket ID No. EPA-HQ-OAR-2017-0664). The results and proposed 
decisions based on the analyses performed pursuant to CAA sections 
112(d)(2) and (3) are presented in section IV.A of this preamble.

B. How did we perform the technology review?

    Emissions data collected as part of the 2022 CAA section 114 
information request indicated that indurating furnaces using wet 
scrubbers to meet the NESHAP emissions standards have significantly 
lower acid gas emissions than those using other types of PM control. 
These emissions data were not available to us at the time of the 2020 
technology review. Based on the new data, we determined it was 
appropriate to revisit the existing standards for HCl and HF in light 
of the air pollution control technologies available to control HCl and 
HF emissions from indurating furnaces.
    When we conduct technology reviews, we primarily focus 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 environmental impacts. We also consider 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, we consider the appropriateness of applying 
controls to new sources versus retrofitting existing sources. For this 
exercise, we consider 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 in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT standards) that could result in additional emissions 
reduction;
     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 we originally developed 
(or last updated) the NESHAP, we review a variety of data sources in 
our investigation of potential practices, processes, or controls. 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.

IV. Analytical Results and Proposed Decisions

A. What are the results of our analyses of unregulated pollutants and 
how did we establish the proposed MACT standards?

    In this action, we are proposing mercury MACT standards for new and 
existing indurating furnaces, pursuant to CAA sections 112(d)(2) and 
(3). The results and proposed decisions based on the analyses performed 
pursuant to CAA sections 112(d)(2) and (3) are presented below.
    Before calculating the MACT floor, we evaluated the available data 
on the design and operating characteristics of indurating furnaces to 
determine whether subcategorization was warranted. For each stack test, 
we collected information on the type of indurating furnace tested 
(grate kiln or straight grate indurating furnace), fuels burned, ore 
processed (magnetite or hematite), and the type and quantity of 
taconite pellets produced.
    Regarding furnace type, there are eight straight grate indurating 
furnaces and 13 grate kiln indurating furnaces located at taconite iron 
ore processing facilities in the United States. This includes three 
grate kiln indurating furnaces at the Empire Mining facility. However, 
as discussed in section II.B, above, the Empire Mining facility has 
been indefinitely idled since 2016 and its three grate kiln indurating 
furnaces are not included in any analyses associated with this proposed 
action. Grate kiln furnaces consist of a moving grate and rotary kiln. 
Unfired (green) pellets are placed directly on a travelling grate which 
transports the pellets through a dryer and pre-heater to the rotary 
kiln, where induration occurs. Straight grate furnaces consist of a 
continuously moving grate that carries the green pellets through the 
furnace's different temperature zones. Unlike the grate kiln furnace 
where the green pellets are placed directly on the grate, the green 
pellets in a straight grate furnace are placed on a 4- to 6-inch layer 
of previously fired pellets known as the hearth layer. The hearth layer 
allows for even air flow and protects the grate from the heat generated 
by the oxidation of the taconite pellets during induration. We compared 
the mercury emissions data for straight grate furnaces with the 
emissions data for grate kiln furnaces to determine whether there was a 
difference in emissions attributable to differences in furnace design. 
We currently have mercury emissions data from stack testing completed 
on five straight grate furnaces and nine grate kiln furnaces. We 
compared the average emissions in pounds of mercury per long ton of 
pellets produced (lb/LT) from grate kiln furnaces with that of straight 
grate furnaces and found the average was slightly higher for grate kiln 
furnaces (1.98 x 10-\5\ lb/LT for grate kiln furnaces versus 
1.80 x 10-\5\ lb/LT for straight grate furnaces). We next 
ranked the 14 furnaces from lowest- to highest-emitter and found that 
one straight grate furnace had an emission rate lower than any of the 
grate kiln furnaces, while the other four straight grate furnaces had 
emissions rates comparable to those of grate kiln furnaces. We propose 
to conclude based on this information that subcategorizing based on 
furnace types is not warranted.
    We also evaluated whether subcategorizing based on the type of ore 
processed would be appropriate. In the United States, there are two 
types of iron ore processed at taconite iron ore processing facilities: 
magnetite and hematite. Only one of the seven taconite plants processes 
hematite ore (Tilden Mining located in Michigan). This plant

[[Page 30924]]

operates two grate kiln furnaces. We currently have mercury emissions 
data for only one of the two grate kiln furnaces located at this plant. 
The mercury emission rate for this grate kiln furnace was lower than 
all but one of the furnaces processing magnetite ore. Since we have 
emissions data for only one of the two grate kiln furnaces currently 
processing hematite, we propose to conclude the data set is too limited 
to justify subcategorizing by ore type.
    Next, we evaluated whether subcategorizing by fuel type would be 
appropriate. Most indurating furnaces can burn natural gas, coal, fuel 
oil, wood, and/or a fuel mixture (e.g., coal and natural gas). However, 
responses to the 2022 CAA section 114 information request indicated 
that natural gas is the most common fuel used in indurating furnaces, 
with natural gas reported as the primary fuel for 14 furnaces. A 
natural gas and wood mix was used as the primary fuel for three 
furnaces, while natural gas and coal or coke blend was reported as the 
primary fuel for one furnace. Most of the furnaces were burning natural 
gas during the testing conducted pursuant to the 2022 CAA section 114 
information request and most stack test data available to us are for 
furnaces burning natural gas. As part of the 2022 CAA section 114 
information request, one facility completed two stack tests--one when 
burning only natural gas and one when co-firing with natural gas and 
coal. The stack tests were completed on the same furnace and the 
results showed a slight increase in mercury emissions from 2.08 x 
10-\5\ lb/LT when burning only natural gas to 2.29 x 
10-\5\ lb/LT when burning a mixture of natural gas and coal. 
We would expect higher mercury emissions from furnaces burning coal 
because coal is known to contain mercury and to emit mercury when 
burned. We would also expect mercury emissions from coal to vary based 
on the quantity of coal burned and the mercury content of the coal 
burned. However, based on the 2022 stack testing described above, the 
contribution of mercury from coal combustion to the overall mercury 
emissions appears to be relatively small. The 2022 stack test data 
suggests that most of the mercury emissions arise from mercury released 
from the taconite ore during induration. We expect that this result is 
likely due primarily to the relatively small mass of coal consumed 
compared to the mass of green pellets processed. For the furnace tested 
in 2022 while co-firing natural gas and coal, the mass of green pellets 
processed per hour was over 110 times greater than the mass of coal 
burned per hour. Based on this information, we do not believe that 
variations in mercury emissions are attributable to fuel-type and 
propose to conclude that subcategorizing based on fuel-type is not 
warranted.
    Finally, we evaluated whether subcategorizing based on the type of 
taconite pellets produced would be appropriate. Taconite iron ore 
processing plants produce two types of pellets: standard (also known as 
acid) pellets and fluxed pellets. Standard pellets are produced by 
mixing the concentrated ore with a binding agent (typically bentonite). 
Fluxed pellets are produced by adding a fluxing agent (typically 
limestone and/or dolomite) in addition to the binding agent. Based on 
the information reported in responses to the 2022 CAA section 114 
information request, 15 of the 18 indurating furnaces produce both 
standard and fluxed pellets, whereas three furnaces located at two 
plants produce exclusively fluxed pellets. A comparison of the mercury 
emissions data indicated no significant difference in mercury emissions 
based on pellet type produced. The maximum measured mercury emissions 
were 2.54 x 10-5 lb/LT while producing flux pellets and 2.51 
x 10-5 lb/LT while producing standard pellets. Based on this 
information, we propose to conclude that subcategorization based on 
pellet type is not appropriate.
    Overall, based on our evaluation of the data, as discussed above, 
we are proposing that subcategorization is not appropriate for these 
emission sources (i.e., the indurating furnaces) when considering 
mercury emissions.
    To determine the proposed MACT standards for mercury for existing 
indurating furnaces in the source category, we evaluated two potential 
options as follows: (1) setting standards at the MACT floor for new and 
existing indurating furnaces; and (2) setting beyond-the-floor MACT 
standards which are more stringent than the MACT floors for new and 
existing indurating furnaces.
    Under Option 1, mercury limits for new and existing indurating 
furnaces would be set at the MACT floor level, based on the 99-percent 
UPL, and would apply individually to each furnace at each facility. We 
calculated the mercury MACT floor limits in units of pounds of mercury 
per long ton of taconite pellets produced (lb/LT) for existing sources 
based on the five best performing furnaces and for new sources based on 
the best performing furnace. The result was a MACT floor limit of 1.4 x 
10-\5\ lb/LT for existing sources and a MACT floor limit of 
3.1 x 10-\6\ lb/LT for new sources.
    We compared the mercury emission rates for each existing indurating 
furnace to the MACT floor limit (i.e., 1.4 x 10-\5\ lb/LT) 
to estimate the number of existing indurating furnaces that would 
require improved performance to meet the MACT floor limits. The 
emissions rates for the 14 indurating furnaces for which we have test 
data were based on the average mercury emissions rates measured during 
stack testing for each of those furnaces. For the remaining four 
indurating furnaces for which stack test data are not available,\9\ we 
used the mercury emissions rates determined through stack testing on 
indurating furnaces of the same size and design located at the same 
plant. Based on this analysis, we estimate that 11 existing indurating 
furnaces would require improved performance to comply with the mercury 
MACT floor limit and seven furnaces would not require improved 
performance. We determined that activated carbon injection (ACI) with a 
high efficiency venturi scrubber would provide the level of mercury 
reduction required for the 11 existing furnaces to achieve compliance 
with the proposed MACT floor.
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    \9\ These include one indurating furnace at the Tilden facility 
and three indurating furnaces at the Northshore facility.
---------------------------------------------------------------------------

    Using ACI with a high efficiency venturi scrubber on the 11 
furnaces we expect would require additional controls would result in a 
combined estimated reduction of 462 pounds of mercury per year from 
these sources. We estimate that the total capital investment to 
retrofit 11 existing furnaces with these controls would be $129 million 
and the total annual costs would be $71 million per year.
    We are proposing to set mercury standards at the MACT floor for new 
and existing sources, as described above. We request comment on this 
proposed approach.
    Under Option 2, we evaluated setting beyond-the-floor MACT 
standards that are more stringent than the MACT floor standards 
discussed in Option 1. We considered limits at levels of 10 percent 
more stringent than the MACT floor, 20 percent more stringent than the 
MACT floor, 30 percent more stringent than the MACT floor, and 40 
percent more stringent than the MACT floor. We considered increased 
stringency at 10 percent intervals up to 40 percent based on 
engineering judgement that such intervals were appropriate due to the 
expected margins of error associated with estimated control 
efficiencies and required carbon injection rates. Using

[[Page 30925]]

smaller intervals would have resulted in overlap of the margins of 
error between intervals and using larger intervals would have resulted 
in less precision of results. Therefore, we decided to use 10 percent 
intervals. Nevertheless, we solicit comments and information regarding 
this approach.
    We estimate that ACI with high efficiency venturi scrubbers could 
achieve standards up to 30 percent more stringent than the MACT floor, 
but at increased rates of carbon injection as the standards increase in 
stringency from 10 percent more stringent than the MACT floor up to 30 
percent more stringent than the MACT floor. Based on our analysis, we 
expect that for standards that are at least 40 percent more stringent 
than the MACT floor, a baghouse would be required after the wet 
scrubber for one facility (Keetac). Of the beyond-the-floor options 
considered, we estimate that the most cost-effective beyond-the-floor 
option would be to set the MACT standard for existing furnaces at a 
level 30 percent more stringent than the MACT floor (i.e., a MACT 
standard of 8.4 x 10-\6\ lb/LT). Under this scenario, we 
estimate that 11 of the 18 existing indurating furnaces would require 
additional controls to meet the beyond-the-floor limit, and that these 
11 furnaces could meet the beyond-the-floor limit using ACI (at a 
higher rate than needed to meet the 10 percent and 20 percent levels) 
with a high efficiency venturi scrubber. Under this approach, we 
estimate a total reduction of 621 pounds of mercury per year from the 
source category at an estimated incremental cost-effectiveness of about 
$46,000 per pound of mercury removed to go beyond the MACT floor. This 
is above the $/pound of mercury reduced that we have historically found 
to be reasonable and cost-effective when considering beyond-the-floor 
options for regulating mercury emissions. Further, our analysis 
indicates that some new furnaces (e.g., if a new furnace was installed 
at the Keetac facility) would require ACI plus baghouses to comply with 
the MACT floor standard and that any increase in stringency of the 
standard (i.e., any beyond-the-floor standard) for new sources, would 
also result in cost-effectiveness, measured in $/pound of mercury 
removed, that is higher on a $/pound basis than cost-effective numbers 
that the EPA has historically considered reasonable when considering 
beyond-the-floor options for regulating mercury emissions. We propose 
to conclude that requiring new or existing indurating furnaces to meet 
beyond-the-floor limits is not reasonable based on the estimated 
capital and operating costs and cost-effectiveness.
    A detailed description of the analyses of mercury emissions, 
including consideration of subcategorization, the calculation of the 
MACT floor limits for new and existing furnaces, and the analysis of 
beyond-the-floor options (including the estimated costs, reductions and 
cost effectiveness of each option), are included in the memorandum, 
Maximum Achievable Control Technology (MACT) Analysis for Proposed 
Mercury Standards for Taconite Iron Ore Indurating Furnaces. A 
description of the APCDs that we expect would be necessary to reduce 
emissions and the estimated costs of those controls are included in the 
memorandum Development of Impacts for the Proposed Amendments to the 
NESHAP for Taconite Iron Ore Processing. Copies of these memoranda are 
available in the docket for this action (Docket ID No. EPA-HQ-OAR-2017-
0664).
1. What alternative compliance provisions are being proposed?
    As discussed in section IV.A, we are proposing to set mercury 
emission standards at the MACT floor level for new and existing sources 
that would apply to indurating furnaces on a unit-by-unit basis. We are 
also proposing an emissions averaging compliance alternative that would 
allow owners and operators of taconite iron ore processing facilities 
to demonstrate compliance by averaging mercury emissions across 
existing indurating furnaces located at the same taconite facility. 
Under this emissions averaging compliance alternative, a taconite iron 
ore processing facility with more than one indurating furnace may 
average mercury emissions across the indurating furnaces located at the 
facility provided that the mercury emissions averaged across all 
indurating furnaces at the facility do not exceed a mercury emission 
limit of 1.26 x 10-\5\ lb/LT, on a production-weighted 
basis. This emission limit reflects a 10 percent adjustment factor to 
the MACT floor standard; according to our analysis, we expect this 
emission limit would result in mercury reductions greater than those 
achieved by application of the MACT floor on a unit-by-unit basis.
    We are proposing this emissions averaging compliance alternative 
for existing indurating furnaces because we expect it will result in a 
greater level of mercury reduction than the unit-by-unit MACT floor 
limit at a lower cost per pound of mercury removed, while also 
providing compliance flexibility. The proposed emissions averaging 
compliance alternative is available only to existing indurating 
furnaces at taconite iron ore processing facilities. New or 
reconstructed indurating furnaces would be subject to the unit-by-unit 
MACT floor standards as discussed in section IV.A above, and would be 
required to comply with those standards on a unit-by-unit basis. 
Specifically, we are proposing that indurating furnaces constructed or 
reconstructed after May 15, 2023 would be considered new sources and 
would be required to comply with the proposed MACT floor emission 
standard for new sources of 3.1 x 10-\6\ lb/LT.
    We expect that the United Taconite, Hibbing, and Minntac taconite 
iron ore processing facilities may elect to utilize this emissions 
averaging compliance alternative. If these three taconite iron ore 
processing facilities utilize the emissions averaging compliance 
alternative, then we expect that six of the 18 indurating furnaces in 
the source category \10\ would require the addition of ACI with a 
venturi scrubber. We estimate that this emissions averaging compliance 
alternative would result in total emissions reductions of 497 pounds of 
mercury per year, assuming that these three taconite iron ore 
processing facilities elect to use the emissions averaging compliance 
alternative to demonstrate compliance with the standards. We estimate 
that, under this emissions averaging compliance alternative, the total 
capital investment for industry would be $90 million and total annual 
costs would be $52 million.
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    \10\ As discussed in section II.B, this excludes the three grate 
kiln indurating furnaces at the Empire Mining facility.
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    We recognize that the EPA has generally imposed limits on the scope 
and nature of emissions averaging programs. These limits include: (1) 
no averaging between different types of pollutants; (2) no averaging 
between sources that are not part of the same affected facility; (3) no 
averaging between individual sources within a single major source if 
the individual sources are not subject to the same NESHAP; and (4) no 
averaging between existing sources and new sources. The emissions 
averaging allowed under the proposed emissions averaging compliance 
option in this action fully satisfies each of these criteria. First, 
emissions averaging would only be allowed for mercury emissions. 
Second, emissions averaging would only be permissible among individual 
existing affected units at a single stationary source (i.e., the 
facility). Third,

[[Page 30926]]

emissions averaging would only be permitted among indurating furnaces 
at the facility. Lastly, new affected sources could not use emissions 
averaging for compliance purposes. Accordingly, we have concluded that 
the averaging of emissions across affected units at a single taconite 
facility is consistent with the CAA.
    We are also proposing to require that each facility that intends to 
utilize the emissions averaging compliance alternative develop an 
emissions averaging plan, which would provide additional assurance that 
the necessary criteria will be followed. We are proposing to require 
that a facility's emissions averaging plan include the identification 
of: (1) all units in the averaging group; (2) the control technology 
installed; (3) the process parameter(s) that will be monitored; (4) the 
specific control technology or pollution prevention measure to be used; 
(5) the test plan for the measurement of the HAP being averaged; and 
(6) the operating parameters to be monitored for each control device. A 
state, local, or tribal regulatory agency that is delegated authority 
for this rulemaking could require the emissions averaging plan to be 
submitted or even approved before emissions averaging could be used. 
Upon receipt, the regulatory authority would not be able to approve an 
emissions averaging plan differing from the eligibility criteria 
contained in the proposed rule.
    We are proposing an emissions averaging compliance alternative 
because we expect it will provide a more flexible and less costly 
alternative to controlling mercury emissions from the source category, 
and we expect it will result in greater annual reductions of mercury 
emissions from the source category than unit-by-unit compliance. We 
expect that the proposed emissions averaging compliance alternative as 
described above would not lessen the stringency of the overall MACT 
floor level of performance and would provide flexibility in compliance, 
cost, and energy savings to owners and operators. We also recognize 
that we must ensure that any emissions averaging option can be 
implemented and enforced, will be clear to sources, and most 
importantly, will be no less stringent than unit-by-unit implementation 
of the MACT floor limits.
    Under the proposed emissions averaging compliance alternative, we 
expect the 10 percent adjustment factor will ensure that the total 
quantity of mercury emitted from a facility's indurating furnaces will 
not be greater than if the facility's furnaces individually complied 
with the unit-by-unit MACT floor standards. We expect that the 
practical outcome of emissions averaging will be mercury emissions 
reductions equivalent to, or greater than, mercury reductions achieved 
through compliance with the MACT floor limits for each discrete 
indurating furnace on a unit-by-unit basis, and that the statutory 
requirement that the MACT standard reflect the maximum achievable 
emissions reductions would therefore be fully effectuated under this 
approach. We request comment on allowing sources to comply with the 
mercury MACT standards through the proposed emissions averaging 
compliance alternative. We also request comment on the appropriate 
adjustment factor to apply under this proposed compliance alternative.
2. What information did the EPA receive regarding mercury variation in 
taconite iron ore?
    On February 14, 2023, the EPA received data from the American Iron 
and Steel Institute (AISI) and U.S. Steel Corporation (U.S. Steel) on 
the variation of mercury concentration within the taconite ore used by 
taconite iron ore processing facilities. U.S. Steel and AISI requested 
that these data be considered as one of the variability factors while 
developing the MACT standards for mercury emitted from indurating 
furnaces. AISI also suggested corrections to the mercury stack test 
emissions data that we used to develop the proposed MACT standards for 
mercury on March 13, 2023. On April 27, 2023, AISI and U.S. Steel also 
submitted suggestions on how to account for variations in mercury, 
chloride, and fluoride concentrations in taconite ore when developing 
standards for emissions of mercury, hydrogen chloride, and hydrogen 
fluoride from indurating furnaces. We did not have sufficient time 
prior to issuing this proposal to fully assess the information 
submitted but have made the submittals available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2017-0664). Therefore, the MACT 
standards for mercury proposed in this action do not include 
consideration of this information submitted by AISI and U.S. Steel. We 
request comment on the submittals in general and on the data on the 
variation of mercury content in taconite ore and whether and to what 
extent this variation should be considered in the development of the 
MACT standards for mercury from indurating furnaces (see discussion in 
section IV.A. of this preamble).

B. What are the results of our technology review and what revisions to 
the MACT standards are we proposing?

    The existing NESHAP for the taconite iron ore processing source 
category includes standards for HCl and HF that utilize PM as a 
surrogate for HCl and HF. As discussed below, however, we are proposing 
to change the way we regulate HCl and HF emissions from the source 
category based on a development in the industry. Specifically, we are 
proposing numerical emission limits for HCl and HF instead of relying 
on PM as a surrogate for emissions of these specific HAP.
    This proposal is consistent with the EPA's authority pursuant to 
CAA section 112(d)(6) to take developments in practices, processes, and 
control technologies into account to determine if it is ``necessary'' 
to revise the MACT standards previously set by the EPA. In this 
proposal, we are using our discretion to revisit part of the 2020 
technology review; our review is limited to developments pertaining to 
the regulation of HCl and HF. The reasons for this proposal are 
discussed below.
    As described in section III.B of this preamble, the technology 
review for the 2020 Taconite Iron Ore Processing RTR rulemaking focused 
on identifying and evaluating potential developments in practices, 
processes, and control technologies that have occurred since the NESHAP 
was promulgated in 2003.\11\ Based on the information available to us 
at the time the 2020 RTR was promulgated, we concluded there were no 
developments in practices, processes, and control technologies for 
indurating furnaces. However, as part of the 2022 CAA section 114 
information request, we collected new data on HCl and HF emissions from 
seven indurating furnaces. Six of the furnaces tested were equipped 
with wet venturi scrubbers and one furnace was equipped with dry 
electrostatic precipitators (ESPs). The HCl and HF emissions data 
showed that wet venturi scrubbers consistently achieved lower HCl 
emissions compared to the furnaces using dry ESPs. The results for HF 
are less clear, but we still expect wet controls achieve better control 
of HF compared to dry controls because HF is quite soluble in water.
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    \11\ For information on the technology review completed in 2020, 
see the memorandum ``Final Technology Review for the Taconite Iron 
Ore Processing Source Category,'' January 3, 2020 (available in the 
docket for this action; Docket Item ID No. EPA-HQ-OAR-2017-0664-
0164).
---------------------------------------------------------------------------

    Based on our review of this new emission data and understanding of 
the chemistry of these compounds, the EPA

[[Page 30927]]

is proposing amendments to the existing NESHAP, pursuant to CAA section 
112(d)(6). The current NESHAP includes PM limits used as a surrogate 
for acid gas emissions. In this action, we are proposing that furnaces 
would be required to comply with the proposed numerical emission limits 
for HCl and HF, which would replace the use of PM emissions as a 
surrogate for emissions of HCl and HF from the source category.
    The proposed revised HCl and HF emission limits for new and 
existing indurating furnaces were determined using a methodology 
similar to, but slightly different than, that used to develop the 
mercury emission limits. The mercury MACT floor limits were derived by 
calculating the UPL based on emissions test data for the top five 
performing (lowest emitting) sources pursuant to CAA section 112(d)(2)/
(3). Since we are proposing a different approach to regulating HCl and 
HF limits from the approach in the current regulations, under the 
limited CAA section 112(d)(6) technology review, the objective was to 
calculate a proposed limit that reflects the performance (i.e., level 
of emissions) of the taconite indurating furnaces that have wet venturi 
scrubbers (i.e., the superior control technology for control of acid 
gases, especially HCl). Therefore, for existing furnaces, we used the 
emissions data from all six furnaces equipped with wet venturi 
scrubbers to calculate a UPL at the 99-percent confidence level for HCl 
and HF, which resulted in the following limits: 4.4 x 10-\2\ 
lb of HCl/LT and 1.2 x 10-\2\ lb of HF/LT. For new sources 
we used the emissions data from the best performing furnace to 
calculate a UPL at the 99-percent confidence level for HCl and HF, 
which resulted in the following limits: 4.4 x 10-\4\ lb of 
HCl/LT and 3.3 x 10-\4\ lb of HF/LT. Based on this data and 
methodology, for existing sources constructed or reconstructed before 
May 15, 2023, we are proposing limits of 4.4 x 10-\2\ lb of 
HCl/LT of taconite pellets produced and 1.2 x 10-\2\ lb of 
HF/LT of taconite pellets produced. For new sources constructed or 
reconstructed after May 15, 2023, we are proposing limits of 4.4 x 
10-\4\ lb of HCl/LT of taconite pellets produced and 3.3 x 
10-\4\ lb of HF/LT of taconite pellets produced.
    We expect that all existing indurating furnaces would be able to 
comply with the proposed numerical HF limit for existing sources 
without the addition of new controls or control measures; we also 
expect that HF emissions from existing sources would incidentally be 
reduced by about 38 tons per year due to controls used to comply with 
the proposed HCl limits (see discussion below). We expect that most 
existing indurating furnaces would be able to comply with the proposed 
HCl limit for existing sources without the addition of new controls or 
control measures. However, we expect that new add-on controls would be 
necessary at two existing indurating furnaces (that is, the two 
indurating furnaces currently equipped with dry ESPs) to comply with 
the proposed HCl limit for existing sources. The estimated total 
capital costs for installing the add-on controls necessary to meet the 
proposed HCl limit for existing sources is $1.1 million, and the total 
annual costs are estimated to be $1.4 million. We estimate that HCl 
emissions would be reduced by 713 tons per year. This results in an 
estimated cost effectiveness of about $1,940 per ton of HCl removed. 
The results of the cost analyses indicate that the estimated cost 
effectiveness is within the range of values that the EPA has previously 
considered to be cost-effective for many different HAP. Detailed 
information on the methodology used to develop the proposed emission 
standards and costs are provided in the memorandum Revised Technology 
Review of Acid Gas Controls for Indurating Furnaces in the Taconite 
Iron Ore Processing Source Category, which is available in the docket 
for this action (Docket ID No. EPA-HQ-OAR-2017-0664). We request 
comment on our proposal to change the way we regulate HCl and HF 
emissions from the source category. Specifically, we request comment on 
our proposal to directly regulate HCl and HF emissions from the source 
category and the numerical emission limits proposed for HCl and HF.

C. What performance testing are we proposing?

    We are proposing that new and existing sources demonstrate 
compliance with the mercury, HCl, and HF standards by performing 
initial performance testing and that the performance testing be 
repeated at the same frequency as required for the existing PM 
standards (i.e., at least twice per title V permit term; that is at 
least twice every 5 years as allowed under 40 CFR 63.9630). Existing 
sources constructed or reconstructed before May 15, 2023 would be 
required to demonstrate initial compliance no later than 180 calendar 
days after the compliance date. New sources constructed or 
reconstructed before May 15, 2023 would be required to complete the 
initial performance testing within 180 days after startup. We are 
proposing the performance tests for mercury be performed using EPA 
Method 29 and that performance tests for HCl and HF be performed using 
EPA Methods 26A. We considered allowing Method 30B as an alternative 
method for mercury performance testing. However, we expect that Method 
30B may not work well at the low expected concentrations of mercury and 
that the relatively high PM in the sample might interfere with Method 
30B. We request comment on whether to allow Method 30B as an 
alternative performance testing method for mercury.
    During the initial and subsequent performance tests, we are 
proposing that testing be completed on every stack associated with each 
indurating furnace within 7 calendar days, to the extent practicable, 
such that the operating characteristics of the furnace and associated 
control device (where applicable) remain representative and consistent 
for the duration of the performance test and under normal operating 
conditions. These testing requirements are consistent with the testing 
requirements for PM in the existing NESHAP (see 40 CFR 63.9620 and 
63.9630).

D. What operating limits and monitoring requirements are we proposing?

    In addition to performance testing, we are proposing owners and 
operators establish operating limits for the parameters listed in Table 
3 for each control device used to comply with the mercury, HCl, and HF 
limits. We are proposing to require owners and operators to establish 
dry sorbent injection rate operating limits for dry sorbent injection 
systems used to comply with the HCl and HF limits, activated carbon 
injection rates for activated carbon injection systems used to comply 
with mercury limits, and pH operating limits for wet scrubbers used to 
comply with the HCl and HF limits (in addition to the requirements in 
the current NESHAP to establish pressure drop and scrubber water flow 
rate for wet scrubbers used to comply with the PM limits). The 
operating limits would be established during the most recent 
performance testing where compliance with the emissions limit is 
demonstrated. Parametric monitoring would be required to ensure the 
control devices operate properly and the source complies with the 
emissions limits on a continuous basis. This approach is consistent 
with the current requirements for demonstrating compliance with the 
existing PM emissions limits. The operating limits for the parameters 
listed in Table 3 would be set as the average of the measured parameter 
during the three test runs of the most recent performance

[[Page 30928]]

test. Owners and operators would be required to comply with the 
existing provisions for installation, operation, and preventive 
maintenance of APCD and monitoring equipment. Owners and operators 
would be required to prepare a preventive maintenance plan, take 
corrective action if an air pollution control device exceeds the 
established operating limit, and prepare and keep records of 
calibration and accuracy checks of the continuous parameter monitoring 
systems (CPMS) to document proper operation and maintenance of each 
monitoring system.

      Table 3--Proposed Operating Limits and Parametric Monitoring
          Requirements for Demonstrating Continuous Compliance
------------------------------------------------------------------------
                                   Establish a          Demonstrate
        For each . . .          minimum operating  continuous compliance
                                 limit for . . .          by . . .
------------------------------------------------------------------------
Wet Scrubber..................  pH...............  Maintain the daily
                                                    average pH equal to
                                                    or greater than the
                                                    pH operating limit
                                                    established during
                                                    the most recent
                                                    performance test.
Dry sorbent injection system..  Sorbent injection  Maintain the daily
                                                    average dry sorbent
                                                    flow rate equal to
                                                    or greater than the
                                                    flow rate operating
                                                    limit established
                                                    during the most
                                                    recent performance
                                                    test.
Activated carbon injection....  Activated carbon   Maintain the daily
                                 injection.         average activated
                                                    carbon injection
                                                    flow rate equal to
                                                    or greater than the
                                                    flow rate operating
                                                    limit established
                                                    during the most
                                                    recent performance
                                                    test.
------------------------------------------------------------------------

E. What recordkeeping and reporting requirements are we proposing?

    We are proposing facilities would be required to submit the 
notifications required in 40 CFR 63.9640; report the results of initial 
and subsequent compliance stack testing for mercury, HCl and HF; 
maintain monitoring records to demonstrate compliance with the proposed 
operating limits for air pollution control devices; comply with the 
recordkeeping requirements in 40 CFR 63.9642; and comply with the 
reporting requirements in 40 CFR 63.9641, including the requirement to 
report deviations from the proposed requirements in the semi-annual 
report and to submit corrective action reports. Facilities that elect 
to comply with the mercury emissions standard using emissions averaging 
would be required to also submit an implementation plan in accordance 
with the proposed provisions in 40 CFR 63.9623(d)(1); maintain a copy 
of the approved implementation plan; and maintain monthly records of 
the quantity of taconite pellets produced by each furnace included in 
the emission average and the calculated average mercury emissions.

F. What are the results of any risk analyses completed for this action?

    In the July 28, 2020, final Taconite Iron Ore Processing RTR rule 
(85 FR 45476), the EPA conducted a residual risk assessment and 
determined that risk from the Taconite Iron Ore Processing source 
category was acceptable and the standards provided an ample margin of 
safety to protect public health (see Docket Item No. EPA-HQ-OAR-2017-
0664-0163), and the EPA therefore did not promulgate standards to 
reduce risk further. Since the final rule, the EPA received new 
facility operation and HAP emissions data from all seven operational 
major source facilities through the 2022 CAA section 114 information 
request and facility stack testing. Specifically, these facilities 
completed stack testing and submitted emissions data for PM, metal HAP, 
HCl and HF for seven indurating furnaces. The EPA used the new 
emissions data that were collected to develop updated estimates of HAP 
emissions from indurating furnaces for each of these facilities. 
Detailed information on the new emissions data is provided in the 
memorandum Emissions Data Collected in 2022 for Indurating Furnaces 
Located at Taconite Iron Ore Processing Plants, which is available in 
the docket for this action (Docket ID No. EPA-HQ-OAR-2017-0664).
    To determine whether these new HAP emissions estimates would 
significantly alter our previous estimates of the human health risk 
posed by the Taconite Iron Ore Processing source category, we performed 
a baseline (baseline means prior to any controls proposed in this 
action) risk analysis using the updated emissions. The methodologies 
used for this risk analysis are the same as those described in section 
III.C. of the preamble to the September 25, 2019, proposed rule 
``National Emission Standards for Hazardous Air Pollutants: Taconite 
Iron Ore Processing Residual Risk and Technology Review'' (84 FR 
50660). We present the results of the new risk analysis in Table 4 of 
this preamble (rows labelled ``Updated Source Category'' and ``Updated 
Whole Facility'') and in more detail in the document Taconite Iron Ore 
Processing 2023 Risk Analysis Report, available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2017-0664). The risk analysis results 
from the July 28, 2020, final Taconite Iron Ore Processing RTR rule (85 
FR 45476) are also provided in Table 4 for comparison (rows labelled 
``Final Rule Source Category'' and ``Final Rule Whole Facility'').

 Table 4--Comparison of Taconite Iron Ore Processing Source Category Baseline Inhalation Risk Assessment Results From the 7/28/20 Final Rule to the 2023
                                                                     Updated Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                               Maximum individual cancer risk (in  Estimated population    Estimated annual       Maximum chronic     Maximum  screening
                                         1 million) \3\            at increased risk of    cancer incidence     noncancer TOSHI \1\  acute  noncancer HQ
                              ------------------------------------    cancer >=1-in-1      (cases per year)   ----------------------         \2\
                                                                          million       ----------------------                      --------------------
       Risk assessment                               Based on     ----------------------                        Based on   Based on
                                Based on actual      allowable      Based on   Based on   Based on   Based on    actual   allowable    Based on actual
                                   emissions         emissions       actual   allowable    actual   allowable  emissions  emissions       emissions
                                                                   emissions  emissions  emissions  emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Final Rule Source Category...  3 (As, Ni, Be)..  5 (As, Ni, Be)..     38,000     43,000      0.001      0.001   0.2 (Mn)   0.2 (Mn)  HQREL = <1 (As)
Updated Source Category \4\..  5 (As, Ni, Be)..  6 (As, Ni, Be)..     56,000     56,400      0.002      0.003   0.1 (Mn)   0.2 (Mn)  HQREL = 1 (As)
Final Rule Whole Facility....  3 (As, Ni, Be)..  ................     40,000  .........      0.001  .........   0.2 (Mn)  .........  ...................

[[Page 30929]]

 
Updated Whole Facility \4\...  5 (As, Ni, Be)..  ................     56,000  .........      0.002  .........   0.2 (Mn)  .........  ...................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The TOSHI is the sum of the chronic noncancer hazard quotients (HQs) for substances that affect the same target organ or organ system.
\2\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop HQ values.
\3\ Five facilities contribute to the maximum individual risk (MIR)--Keetac, Hibbing, Minorca, UTAC, and Minntac.
\4\ Includes updated emissions data received following proposal from the 2022 CAA section 114 information request and any testing data received after
  publication of the RTR final rule.

    The results of the revised inhalation risk modeling, as shown in 
Table 4 of this preamble, indicate that the cancer risk estimates for 
the Taconite Iron Ore Processing source category increased slightly 
from the estimate in the RTR final rule. Specifically, the maximum 
individual cancer risk (MIR) based on actual emissions (lifetime) 
increased from 3-in-1 million to 5-in-1 million (driven by arsenic, 
beryllium and nickel from fugitive dust sources and indurating 
furnaces). The number of people with chronic cancer risks of greater 
than or equal to 1-in-1 million increased from 38,000 to 56,000. The 
total estimated annual cancer incidence (national) based on actual 
emission levels increased from 0.001 to 0.002 excess cancer cases per 
year. The maximum chronic noncancer target organ-specific hazard index 
(TOSHI) value based on actual emissions decreased from 0.2 to 0.1 
(neurological; driven by manganese compounds from fugitive dust and ore 
crushing sources). The maximum screening acute noncancer HQ value (off-
facility site) remained about 1 (driven by arsenic from fugitive dust 
and ore crushing sources).
    Regarding multipathway risk, in the July 28, 2020, final Taconite 
Iron Ore Processing RTR rule (85 FR 45476), we concluded that there was 
``no significant potential for multipathway health effects.'' This 
determination was based upon a site-specific multipathway assessment 
that found cancer risk based on the fisher scenario was 0.2-in-1 
million (arsenic). In addition, the noncancer hazard quotients were 
less than 1 for mercury (0.02) and for cadmium (0.01). We performed a 
linear scaling of the multipathway risks using a conservatively high 
estimate of the revised emissions for arsenic (4.4 times increase in 
emissions), mercury (2.4 times increase in emissions) and cadmium 
(emissions decreased). Using these scaling factors, the adjusted 
multipathway risks for cancer increased to 0.9-in-1 million (arsenic), 
and the adjusted noncancer hazard quotient for mercury increased to 
0.05 (arsenic was unchanged).
    The results of the updated inhalation risk analysis and the updated 
multipathway risk assessment indicate that the risk for the Taconite 
Iron Ore Processing source category has increased slightly, but still 
remains well within the range of acceptability. Further, we have not 
identified any information that would change the ample margin of safety 
analysis finalized in the 2020 RTR final rule. Based on these results, 
we are not proposing any changes to our decisions regarding risk 
acceptability or ample margin of safety that were made under CAA 
section 112(f) in the July 28, 2020, Taconite Iron Ore Processing RTR 
final rule (85 FR 45476).

G. What other actions are we proposing?

    On January 5, 2022, the EPA published in the Federal Register (87 
FR 393) a final rule amending the list of HAP under the CAA to add 1-
bromopropane (1-BP) in response to public petitions previously granted 
by the EPA. 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 Taconite Iron Ore Processing source category, we 
conclude that the inclusion of 1-BP as a HAP will not impact the NESHAP 
because, based on available information, we expect that 1-BP is not 
emitted from this source category. As a result, no changes are being 
proposed to the rule based on the addition of 1-BP to the CAA section 
112 HAP list. Nevertheless, we are requesting comments and data 
regarding any potential emissions of 1-BP from this source category.
    Also, in addition to the proposed actions described above, we are 
proposing to update the electronic reporting requirements found in 40 
CFR 63.9641(c) and 40 CFR 63.9641(f)(3) to reflect new procedures for 
reporting CBI. Specifically, we are proposing to include an email 
address that owners and operators may use to electronically submit 
compliance reports containing CBI to the OAQPS CBI Office.

H. What compliance dates are we proposing?

    The amendments to the Taconite Iron Ore Processing NESHAP proposed 
in this rulemaking for adoption of mercury standards under CAA sections 
112(d)(2) and (3) and adoption of HCl and HF standards under CAA 
section 112(d)(6) are subject to the compliance deadlines outlined in 
the CAA under section 112(i). For existing sources, CAA section 
112(i)(3) requires 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.\12\ 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. The EPA projects 
that several existing sources would need to install new add-on controls 
to comply with the proposed mercury limits; we also expect that one or 
two facilities will need to install controls for acid gases. We expect 
that these sources will require substantial time to plan, design, 
construct, and begin operating the new add-on controls, and to conduct 
performance testing, and implement monitoring to comply with the 
revised provisions. Therefore, we are proposing to allow 3 years for 
existing sources constructed or reconstructed before May 15, 2023 to 
become compliant with the new emission standards for mercury, HCl and 
HF. These sources would have

[[Page 30930]]

to continue to meet the current provisions of 40 CFR part 63, subpart 
RRRRR.
---------------------------------------------------------------------------

    \12\ Association of Battery Recyclers v. EPA, 716 F.3d 667, 672 
(D.C. Cir. 2013) (``Section 112(i)(3)'s 3-year maximum compliance 
period applies generally to any emission standard . . . promulgated 
under [section 112]'' (brackets in original)).
---------------------------------------------------------------------------

    Pursuant to CAA section 112(i), we are proposing that all affected 
sources that commenced construction or reconstruction after May 15, 
2023 would comply with the provisions by the effective date of the 
final rule or upon startup, whichever is later. The final action is not 
a ``major rule'' as defined by 5 U.S.C. 804(2), so the effective date 
of the final rule will be the promulgation date as specified in CAA 
section 112(d)(10).
    We solicit comment on these proposed compliance periods, and we 
specifically request submission of information from sources in this 
source category regarding specific actions that would need to be 
undertaken to comply with the proposed standards and the time needed to 
make the adjustments for compliance with any of the proposed standards. 
We note that information provided may result in changes to the proposed 
compliance dates.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    As previously indicated, there are currently seven major sources 
subject to the Taconite Iron Ore Manufacturing NESHAP that are 
operating in the United States. One additional major source, Empire 
Mining, is subject and has a permit to operate, but has been 
indefinitely idled since 2016. The NESHAP for Taconite Iron Ore 
Processing applies to the owner or operator of a taconite iron ore 
processing plant that is (or is part of) a major source of HAP 
emissions. A taconite iron ore processing plant is any facility engaged 
in separating and concentrating iron ore from taconite ore to produce 
taconite pellets. Taconite iron ore processing includes the following 
processes: liberation of the iron ore by wet or dry crushing and 
grinding in gyratory crushers, cone crushers, rod mills, and ball 
mills; concentration of the iron ore by magnetic separation or 
flotation; pelletizing by wet tumbling with a balling drum or balling 
disc; induration using a straight grate or grate kiln indurating 
furnace; and finished pellet handling. A major source of HAP is a plant 
site that emits, or has the potential to emit, any single HAP at a rate 
of 9.07 megagrams (10 tons) or more, or any combination of HAP at a 
rate of 22.68 megagrams (25 tons) or more per year from all emission 
sources at the plant site.

B. What are the air quality impacts?

    This action proposes first-time emissions standards for mercury and 
revised emissions standards for HCl and HF and would require some 
plants to install additional controls on their indurating furnaces. For 
HCl, HF and mercury, installation of controls will result in a combined 
reduction of total HAP of 751 tons of HAP per year (tpy). Specifically, 
we estimate that the installation of controls will reduce HCl and HF 
emissions by 713 tpy and 38 tpy, respectively, and will reduce mercury 
emissions by 497 pounds per year (0.25 tpy).
    Indirect or secondary air emissions impacts are impacts that would 
result from the increased electricity usage associated with the 
operation of control devices (e.g., increased secondary emissions of 
criteria pollutants from power plants). Energy impacts consist of the 
electricity and steam needed to operate control devices and other 
equipment. We find that the secondary impacts of this action are 
minimal. Refer to the memorandum Development of Impacts for the 
Proposed Amendments to the NESHAP for Taconite Iron Ore Processing for 
a detailed discussion of the analyses performed on emissions reductions 
and potential secondary impacts. This memorandum is available in the 
docket for this action (Docket ID No. EPA-HQ-OAR-2017-0664).

C. What are the cost impacts?

    This action proposes emission limits for new and existing sources 
in the Taconite Iron Ore Processing source category. Although this 
action contains requirements for new sources, we are not aware of any 
new sources being constructed now or planned in the next year, and, 
consequently, we did not estimate any cost impacts for new sources. We 
estimate the total capital and annualized costs of the proposed rule 
for existing sources in the Taconite Iron Ore Processing source 
category will be approximately $91 million and $54 million per year, 
respectively. The annual costs are based on operation and maintenance 
of added control systems. A memorandum titled Development of Impacts 
for the Proposed Amendments to the NESHAP for Taconite Iron Ore 
Processing includes details of our cost assessment, expected emission 
reductions and estimated secondary impacts. A copy of this memorandum 
is available in the docket for this action (Docket ID No. EPA-HQ-OAR-
2017-0664).

D. What are the economic impacts?

    For the proposed rule, the EPA estimated the cost of installing 
additional APCD in order to comply with the proposed emission limits. 
This includes the capital costs of the initial installation, and 
subsequent maintenance and operation of the controls. To assess the 
potential economic impacts, the expected annual cost was compared to 
the total sales revenue for the ultimate owners of affected facilities. 
For this rulemaking, the expected annual cost is $8 million (on 
average) for each facility, with an estimated nationwide annual cost of 
$54 million per year. The seven affected facilities are owned by two 
parent companies (U.S. Steel and Cleveland-Cliffs, Inc.). Neither 
parent company qualifies as a small business, and the total costs 
associated with the proposed amendments are expected to be less than 1 
percent of annual sales revenue per ultimate owner.
    The EPA also modeled the impacts of the proposed amendments using 
two standard partial equilibrium economic models: one for taconite iron 
ore pellets and one for steel mill products. The EPA linked these two 
partial equilibrium models by specifying interactions between supply 
and demand in both markets and solving for changes in prices and 
quantity across both markets simultaneously. These models use baseline 
economic data from 2019 to project the impact of the proposed NESHAP 
amendments on the market for taconite iron ore pellets and steel mill 
products. The models allow the EPA to project facility- and market-
level price and quantity changes for taconite iron ore pellets and 
market-level price and quantity changes for steel mill products, 
including changes in imports and exports in both markets. Under the 
proposed amendments, the models project a 0.26 percent fall in the 
quantity of domestically produced taconite iron ore pellets along with 
a 0.58 percent increase in their price. The models also project a 0.02 
percent fall in the quantity of domestically produced steel mill 
products along with an 0.01 percent increase in their price.
    Information on our economic impact estimates on the sources in the 
Taconite Iron Ore Processing source category is available in the 
document Economic Impact Analysis for the Proposed National Emission 
Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing 
Amendments (EIA), available in the docket for this action (Docket ID 
No. EPA-HQ-OAR-2017-0664). The EIA also includes an analysis of less 
and more stringent alternative

[[Page 30931]]

regulatory options for mercury and acid gases.

E. What analysis of environmental justice did we conduct?

    Consistent with the EPA's commitment to integrating environmental 
justice (EJ) in the Agency's actions, and following the directives set 
forth in multiple Executive orders, the Agency has evaluated the 
impacts of this action on communities with EJ concerns. Overall, we 
found that in the population living in close proximity of facilities, 
the following demographic groups were above the national average: 
White, Native American, and people living below the poverty level. For 
two facilities, the percentage of the population that is Native 
American was more than double the national average.
    Executive Order 12898 directs the EPA to identify the populations 
of concern who are most likely to experience unequal burdens from 
environmental harms, which are specifically minority populations 
(people of color), low-income populations, and indigenous peoples (59 
FR 7629; February 16, 1994). Additionally, Executive Order 13985 is 
intended to advance racial equity and support underserved communities 
through Federal Government actions (86 FR 7009; January 20, 2021). The 
EPA defines EJ as ``the fair treatment and meaningful involvement of 
all people regardless of race, color, national origin, or income, with 
respect to the development, implementation, and enforcement of 
environmental laws, regulations, and policies.'' \13\ The EPA further 
defines fair treatment to mean that ``no group of people should bear a 
disproportionate burden of environmental harms and risks, including 
those resulting from the negative environmental consequences of 
industrial, governmental, and commercial operations or programs and 
policies.''
---------------------------------------------------------------------------

    \13\ https://www.epa.gov/environmentaljustice.
---------------------------------------------------------------------------

    For the Taconite Iron Ore Processing source category, the EPA 
examined the potential for EJ concerns by conducting a proximity 
demographic analysis. The proximity demographic analysis is an 
assessment of individual demographic groups in the total population 
living within 10 kilometers (km) and 50 km of the facilities. The EPA 
then compared the data from this analysis to the national average for 
each of the demographic groups. Since the taconite iron ore processing 
facilities are very large, a radius of 10 km was used as the near 
facility distance for the proximity analysis. A distance closer than 10 
km does not yield adequate population size for the results. The results 
of the proximity analysis are in the technical report Analysis of 
Demographic Factors For Populations Living Near Taconite Iron Ore 
Processing Source Category Operations, available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2017-0664).
    The results in Table 5 show that for the population living within 
10 km of the eight facilities, the following demographic groups were 
above the national average: White (93 percent versus 60 percent 
nationally), Native American (0.8 percent versus 0.7 percent 
nationally), and people living below the poverty level (15 percent 
versus 13 percent nationally). For two facilities, the percentage of 
the population living within 10 km that is Native American (1.9 percent 
and 2.3 percent) was more than double the national average (0.7 
percent).

     Table 5--Taconite Iron Ore Processing Source Category Proximity
                           Demographic Results
------------------------------------------------------------------------
                                                       Total population
                                                       living within 10
        Demographic group             Nationwide        km of taconite
                                                          facilities
------------------------------------------------------------------------
Total Population................  328M..............  59,000.
Number of Facilities............  ..................  8.
------------------------------------------------------------------------
            Race and Ethnicity by Percent [Number of people]
------------------------------------------------------------------------
White...........................  60 percent [197M].  93 percent
                                                       [54,900].
African American................  12 percent [40M]..  1 percent [600].
Native American.................  0.7 percent [2M]..  0.8 percent [500].
Hispanic or Latino (includes      19 percent [62M]..  0.9 percent [500].
 white and nonwhite).
Other and Multiracial...........  8 percent [27M]...  4 percent [2,400].
------------------------------------------------------------------------
                  Income by Percent [Number of People]
------------------------------------------------------------------------
Below Poverty Level.............  13 percent [44M]..  15 percent
                                                       [9,000].
Above Poverty Level.............  87 percent [284M].  85 percent
                                                       [50,000].
------------------------------------------------------------------------
                 Education by Percent [Number of People]
------------------------------------------------------------------------
Over 25 and without a High        12 percent [40M]..  6 percent [3,600].
 School Diploma.
Over 25 and with a High School    88 percent [288M].  94 percent
 Diploma.                                              [55,400].
------------------------------------------------------------------------
          Linguistically Isolated by Percent [Number of People]
------------------------------------------------------------------------
Linguistically Isolated.........  5 percent [18M]...  0.4 percent [200].
------------------------------------------------------------------------
Notes:
 Nationwide population and demographic percentages are based on
  Census' 2015-2019 ACS 5-year block group averages. Total population
  count within 10km is based on 2010 Decennial Census block population.
 To avoid double counting, the ``Hispanic or Latino'' category
  is treated as a distinct demographic category. A person who identifies
  as Hispanic or Latino is counted as Hispanic/Latino, regardless of
  race.
 The sum of individual populations with a demographic category
  may not add up to total due to rounding.

[[Page 30932]]

    The proposed actions, if finalized, will ensure compliance via 
frequent compliance testing and monitoring of control device operating 
parameters, and reduce emissions via new standards for mercury and 
revised standards for HCl and HF and by requiring affected sources to 
meet all the emissions standards at all times (including periods of 
startup, shutdown, and malfunctions). Therefore, the EPA expects that 
there would be a positive, beneficial effect for all populations in 
proximity to affected sources, including in communities potentially 
overburdened by pollution, which are often minority, low-income and 
indigenous communities.

F. What analysis of children's environmental health did we conduct?

    In the July 28, 2020, final Taconite Iron Ore Processing RTR rule 
(85 FR 45476), the EPA conducted a residual risk assessment and 
determined that risk from the Taconite Iron Ore Processing source 
category was acceptable, and the standards provided an ample margin of 
safety to protect public health (see Docket Item No. EPA-HQ-OAR-2017-
0664-0163). For this rulemaking, we updated that risk analysis using 
new emissions data that the EPA received for some HAP emissions sources 
at the taconite facilities. We determined that these new HAP emissions 
estimates would not significantly change our previous estimates of the 
human health risk posed by the Taconite Iron Ore Processing source 
category (see section IV.F of this preamble). In addition, this action 
proposes first-time emissions standards for mercury and revised 
emissions standards for HCl and HF and would further reduce emissions. 
Specifically, we estimate that the installation of controls will reduce 
HCl and HF emissions by 713 tpy and 38 tpy, respectively, and will 
reduce mercury emissions by 497 pounds per year (0.25 tpy).
    This action's health and risk assessments are protective of the 
most vulnerable populations, including children, due to how we 
determine exposure and through the health benchmarks that we use. 
Specifically, the risk assessments we perform assume a lifetime of 
exposure, in which populations are conservatively presumed to be 
exposed to airborne concentrations at their residence continuously, 24 
hours per day for a 70-year lifetime, including childhood. With regards 
to children's potentially greater susceptibility to noncancer 
toxicants, the assessments rely on the EPA's (or comparable) hazard 
identification and dose-response values that have been developed to be 
protective for all subgroups of the general population, including 
children. For more information on the risk assessment methods, see the 
risk report for the July 28, 2020, final Taconite RTR rule (85 FR 
45476), which is available in the docket (Docket ID No. EPA-HQ-OAR-
2017-0664).

VI. Request for Comments

    We solicit comments on this proposed action. In addition to general 
comments on this proposed action, we request comment on our proposal to 
set mercury emission limits at the MACT floor level. We also request 
comment on whether to allow sources to comply with the mercury MACT 
standards through the proposed emissions averaging compliance 
alternative and on the appropriate adjustment factor to apply under the 
emissions averaging compliance alternative. In addition, we request 
comment and data on the variation of mercury content in taconite ore 
and whether and to what extent this variation should be considered in 
the development of the MACT standards for mercury from indurating 
furnaces. We also solicit comment on the data submitted by AISI and 
U.S. Steel concerning variation of mercury content in taconite ore (see 
discussion in section IV.A. of this preamble). In addition, we request 
comment on whether we should allow use of EPA Method 30B for affected 
facilities to demonstrate compliance with the proposed MACT standards 
for mercury. Further, we request comment on our proposal to change the 
way we regulate HCl and HF emissions from the source category. 
Specifically, we request comment on our proposal to directly regulate 
HCl and HF emissions from the source category and the numerical 
emission limits proposed for HCl and HF.

VII. Submitting Data Corrections

    The site-specific emissions data used in developing the proposed 
MACT standards for HCl, mercury, and HF, as emitted from the Taconite 
Iron Ore Processing source category, are provided in the docket for 
this action (Docket ID No. EPA-HQ-OAR-2017-0664).
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern, and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes.
    For information on how to submit comments, including the submittal 
of data corrections, refer to the instructions provided in the 
introduction of this preamble.

VIII. Statutory and Executive order Reviews

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

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the PRA. The Information Collection Request (ICR) document 
that the EPA prepared has been assigned EPA ICR number 2050.10. You can 
find a copy of the ICR in the docket for this action, and it is briefly 
summarized here.
    We are proposing changes to the reporting and recordkeeping 
requirements for the Taconite Iron Ore Processing NESHAP by 
incorporating the reporting and recordkeeping requirements associated 
with the new and existing source MACT standards for mercury and 
revising the emission standards for HCl and HF.
    Respondents/affected entities: Owners or operators of taconite iron 
ore plants that are major sources, or that are located at, or are part 
of, major sources of HAP emissions.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart RRRRR).
    Estimated number of respondents: On average over the next 3 years, 
approximately seven existing major sources will be subject to these 
standards. It is also estimated that no additional respondent will 
become subject to the emission standards over the 3-year period.
    Frequency of response: The frequency of responses varies depending 
on the burden item.
    Total estimated burden: The average annual burden to industry over 
the next 3 years from the proposed recordkeeping and reporting 
requirements is estimated to be 1,580 hours per year. Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: The annual recordkeeping and reporting cost 
for all facilities to comply with all the

[[Page 30933]]

requirements in the NESHAP is estimated to be $177,000 per year. The 
average annual recordkeeping and reporting cost for this rulemaking is 
estimated to be $25,000 per facility per year.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates and any suggested methods for 
minimizing respondent burden to the EPA using the docket identified at 
the beginning of this proposed rule. The EPA will respond to any ICR-
related comments in the final rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs using 
the interface at www.reginfo.gov/public/do/PRAMain. Find this 
particular information collection by selecting ``Currently under 
Review--Open for Public Comments'' or by using the search function. OMB 
must receive comments no later than July 14, 2023.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. The Agency 
confirmed through responses to a CAA section 114 information request 
that there are only seven taconite iron ore processing plants currently 
operating in the United States and that these plants are owned by two 
parent companies that do not meet the definition of small businesses, 
as defined by the U.S. Small Business Administration.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. This action imposes 
no enforceable duty on any state, local, or tribal governments or the 
private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national Government and the states, or on the distribution of power 
and responsibilities among the various levels of Government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. None of the taconite iron ore processing plants 
are owned or operated by Indian tribal governments. Thus, Executive 
Order 13175 does not apply to this action.
    Consistent with the EPA Policy on Consultation and Coordination 
with Indian Tribes, the EPA consulted with tribal officials during the 
development of this action. On January 12, 2022, the EPA's Office of 
Air and Radiation held a Tribal consultation meeting with 
representatives from the Fond du Lac Band of Lake Superior Chippewa 
Reservation and the Leech Lake Band of Ojibwe Reservation to discuss 
the EPA's CAA section 114 information request, and the general plans 
for this proposed rulemaking and related issues. A summary of that 
consultation is provided in the document Consultation with the Fond du 
Lac Band of Lake Superior Chippewa and the Leech Lake Band of Ojibwe 
regarding Notice of Proposed Rulemaking for the National Emission 
Standards for Hazardous Air Pollutants for Taconite Iron Ore Processing 
Amendments on January 12, 2022, which is available in the docket for 
this action. Furthermore, EPA staff attended several meetings hosted by 
the Minnesota Pollution Control Agency (MPCA), along with 
representatives from Tribal Nations, MPCA, the Michigan Attorney 
General's Office, the Minnesota Attorney General's Office, 
EarthJustice, and the Michigan Department of Environment, Great Lakes, 
and Energy, to discuss concerns related to HAP emissions from taconite 
iron ore processing facilities. In addition, the EPA received letters 
from representatives of the Leech Lake Band of Ojibwe and the Fond du 
Lac Band of Lake Superior Chippewa expressing concerns of these Tribal 
Nations due to HAP emissions from the taconite iron ore processing 
facilities. These letters, and responses from the EPA, are provided in 
the docket for this action (Docket ID No. EPA-HQ-OAR-2017-0664).

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

    Executive Order 13045 (62 FR 19885; April 23, 1997) directs Federal 
agencies to include an evaluation of the health and safety effects of 
the planned regulation on children in Federal health and safety 
standards and explain why the regulation is preferable to potentially 
effective and reasonably feasible alternatives. This action is not 
subject to Executive Order 13045 because it is not economically 
significant as defined in Executive Order 12866, and because the EPA 
does not believe the environmental health or safety risks addressed by 
this action present a disproportionate risk to children. In this action 
the EPA proposes emission standards for one previously unregulated 
pollutant (mercury) and revised emissions standards for two currently 
regulated pollutants (HCl and HF). Therefore, the rulemaking proposes 
health benefits to children by reducing the level of HAP emissions 
emitted from taconite iron ore processing plants.
    However, the EPA's Policy on Children's Health applies to this 
action. This action is subject to the EPA's Policy on Children's Health 
\14\ because the proposed rule has considerations for human health. 
Information on how the policy was applied is available in section V.F 
``What analysis of children's environmental health did we conduct'' of 
this preamble.
---------------------------------------------------------------------------

    \14\ https://www.epa.gov/children/childrens-health-policy-and-plan.
---------------------------------------------------------------------------

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. In this action, the EPA is proposing to 
set emission standards for one previously unregulated pollutant 
(mercury) and to revise emission standards for two currently regulated 
pollutants (HCl and HF). This does not impact energy supply, 
distribution, or use.

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

    This action involves technical standards. Therefore, the EPA 
conducted searches for the Taconite Iron Ore Processing NESHAP through 
the Enhanced National Standards Systems Network (NSSN) Database managed 
by the American National Standards Institute (ANSI). We also conducted 
a review of voluntary consensus standards (VCS) organizations and 
accessed and searched their databases. We conducted searches for EPA 
Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 5, 5D, 17, 26A and 
29. During the EPA's VCS

[[Page 30934]]

search, if the title or abstract (if provided) of the VCS described 
technical sampling and analytical procedures that are similar to the 
EPA's reference method, the EPA ordered a copy of the standard and 
reviewed it as a potential equivalent method. We reviewed all potential 
standards to determine the practicality of the VCS for this proposed 
rule. This review requires significant method validation data that meet 
the requirements of EPA Method 301 for accepting alternative methods or 
scientific, engineering, and policy equivalence to procedures in the 
EPA referenced methods. The EPA may reconsider determinations of 
impracticality when additional information is available for any 
particular VCS.
    No voluntary consensus standards were identified for EPA Methods 1, 
1A, 2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 4, 5, 5D, 17 or 26A. Two voluntary 
consensus standards were identified as acceptable alternatives to EPA 
Methods 3B and 29.
    The EPA proposes to allow use of the VCS ANSI/ASME PTC 19.10-1981 
Part 10 (2010), ``Flue and Exhaust Gas Analyses'' as an acceptable 
alternative to EPA Method 3B for the manual procedures only and not the 
instrumental procedures. The ANSI/ASME PTC 19.10-1981 Part 10 method 
incorporates both manual and instrumental methodologies for the 
determination of oxygen content. The manual method segment of the 
oxygen determination is performed through the absorption of oxygen. 
This method is available at the American National Standards Institute 
(ANSI), 1899 L Street NW, 11th Floor, Washington, DC 20036 and the 
American Society of Mechanical Engineers (ASME), Three Park Avenue, New 
York, NY 10016-5990. See https://www.ansi.org and https://www.asme.org. 
The standard is available to everyone at a cost determined by ANSI/ASME 
($96). The cost of obtaining this method is not a significant financial 
burden, making the methods reasonably available.
    The EPA proposes to allow use of the VCS ASTM D6784-16, ``Standard 
Test Method for Elemental, Oxidized, Particle-Bound and Total Mercury 
in Flue Gas Generated from Coal-Fired Stationary Sources (Ontario Hydro 
Method)'' as an acceptable alternative to EPA Method 29 (mercury 
portion only) as a method for measuring mercury concentrations ranging 
from approximately 0.5 to 100 micrograms per normal cubic meter 
([micro]g/Nm\3\). This test method describes equipment and procedures 
for obtaining samples from effluent ducts and stacks, equipment and 
procedures for laboratory analysis, and procedures for calculating 
results. VCS ASTM D6784-16 allows for additional flexibility in the 
sampling and analytical procedures from the earlier version of the same 
standard VCS ASTM D6784-02 (Reapproved 2008). VCS ASTM D6784-16 allows 
for the use of either an EPA Method 17 sampling configuration with a 
fixed (single) point where the flue gas is not stratified, or an EPA 
Method 5 sampling configuration with a multi-point traverse. For this 
action, only the EPA Method 5 sampling configuration with a multi-point 
traverse can be used. This method is available at ASTM International, 
1850 M Street NW, Suite 1030, Washington, DC 20036. See https://www.astm.org/. The standard is available to everyone at a cost 
determined by ASTM ($82). The cost of obtaining this method is not a 
significant financial burden, making the method reasonably available.
    Additional detailed information on the VCS search and determination 
can be found in the memorandum, Voluntary Consensus Standard Results 
for National Emission Standards for Hazardous Air Pollutants: Taconite 
Iron Ore Processing, which is available in the docket for this action 
(Docket ID No. EPA-HQ-OAR-2017-0664). The EPA welcomes comments on this 
aspect of the proposed rulemaking and, specifically, invites the public 
to identify potentially applicable VCS and to explain why such 
standards should be used in this regulation.
    The EPA is incorporating by reference the VCS ANSI/ASME PTC 19.10-
1981 Part 10 (2010), ``Flue and Exhaust Gas Analyses'' as an acceptable 
alternative to EPA Method 3B for the determination of oxygen content 
(manual procedures only) and the VCS ASTM D6784-16, ``Standard Test 
Method for Elemental, Oxidized, Particle-Bound and Total Mercury in 
Flue Gas Generated from Coal-Fired Stationary Sources (Ontario Hydro 
Method),'' as an acceptable alternative to EPA Method 29 (mercury 
portion only) as a method for measuring elemental, oxidized, particle-
bound, and total mercury.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629; February 16, 1994) directs 
Federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on minority populations (people of color and/or indigenous 
peoples) and low-income populations.
    The EPA anticipates that the human health or environmental 
conditions that exist prior to this action result in or have the 
potential to result in disproportionate and adverse human health or 
environmental effects on low-income populations and/or indigenous 
peoples. The assessment of populations in close proximity of taconite 
iron ore processing plants shows Native American and low-income 
populations are higher than the national average (see section V.F. of 
this preamble). The higher percentages are driven by two of the eight 
facilities in the source category. The EPA anticipates that this action 
is likely to reduce existing disproportionate and adverse effects on 
low-income populations and/or indigenous peoples. The EPA is proposing 
new MACT standards for mercury and revised standards for HCl and HF. 
The EPA expects that five facilities would have to implement control 
measures to reduce emissions to comply with the new and revised MACT 
standards and that HAP exposures for indigenous peoples and low-income 
individuals living near these five facilities would decrease. The 
information supporting this Executive order review is contained in 
section V.E of this preamble.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Incorporation by reference, Reporting and recordkeeping 
requirements.

Michael S. Regan,
Administrator.
[FR Doc. 2023-10068 Filed 5-12-23; 8:45 am]
BILLING CODE 6560-50-P