Proposed Rule2024-27635
Air Plan Approval; Michigan and Minnesota; Revision to Taconite Federal Implementation Plan
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
December 4, 2024
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to finalize nitrogen oxide (NO<INF>X</INF>) and/or sulfur dioxide (SO<INF>2</INF>) limits for the indurating furnaces at five taconite facilities in accordance with the procedures set forth in the Federal implementation plan (FIP) addressing the requirement for best available retrofit technology (BART) at taconite facilities. EPA is also proposing to modify the Upper Predictive Limit (UPL) equations used to establish NO<INF>X</INF> and SO<INF>2</INF> emission limits under the FIP. Finally, EPA is proposing to revise reporting provisions to require reports to be submitted to EPA electronically. EPA is proposing these actions pursuant to sections 110 and 169A of the Clean Air Act (CAA).
Full Text
<html>
<head>
<title>Federal Register, Volume 89 Issue 233 (Wednesday, December 4, 2024)</title>
</head>
<body><pre>
[Federal Register Volume 89, Number 233 (Wednesday, December 4, 2024)]
[Proposed Rules]
[Pages 96152-96166]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-27635]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R05-OAR-2024-0215; FRL-12351-01-R5]
Air Plan Approval; Michigan and Minnesota; Revision to Taconite
Federal Implementation Plan
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is proposing to
finalize nitrogen oxide (NO<INF>X</INF>) and/or sulfur dioxide
(SO<INF>2</INF>) limits for the indurating furnaces at five taconite
facilities in accordance with the procedures set forth in the Federal
implementation plan (FIP) addressing the requirement for best available
retrofit technology (BART) at taconite facilities. EPA is also
proposing to modify the Upper Predictive Limit (UPL) equations used to
establish NO<INF>X</INF> and SO<INF>2</INF> emission limits under the
FIP. Finally, EPA is proposing to revise reporting provisions to
require reports to be submitted to EPA electronically. EPA is proposing
these actions pursuant to sections 110 and 169A of the Clean Air Act
(CAA).
[[Page 96153]]
DATES: Comments must be received on or before January 21, 2025.
Virtual Public Hearing. EPA will hold a virtual public hearing to
solicit comments on December 19, 2024. The last day to pre-register to
present at the hearing will be December 16, 2024. On December 16, 2024,
EPA will post a general agenda for the hearing that will list pre-
registered presenters in approximate order at <a href="https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn">https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn</a>.
If you require the services of a translator or a special accommodation
such as audio description/closed captioning, please pre-register for
the hearing and describe your needs by December 11, 2024.
For more information on the virtual public hearing, see
SUPPLEMENTARY INFORMATION.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2024-0215 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>, or via email to
<a href="/cdn-cgi/l/email-protection#88e9fafae9a6fbe9fae9e0c8edf8e9a6efe7fe"><span class="__cf_email__" data-cfemail="b9d8cbcbd897cad8cbd8d1f9dcc9d897ded6cf">[email protected]</span></a>. For comments submitted at <a href="http://Regulations.gov">Regulations.gov</a>, follow
the online instructions for submitting comments. Once submitted,
comments cannot be edited or removed from the docket. EPA may publish
any comment received to its public docket. Do not submit to EPA's
docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> any information you consider to
be Confidential Business Information (CBI), Proprietary Business
Information (PBI), or other information whose disclosure is restricted
by statute. 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. 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, please
contact the person identified in the FOR FURTHER INFORMATION CONTACT
section. For the full EPA public comment policy, information about CBI,
PBI, or multimedia submissions, and general guidance on making
effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
FOR FURTHER INFORMATION CONTACT: Kathleen D'Agostino, Environmental
Scientist, Air and Radiation Division (AR18J), Environmental Protection
Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604,
(312) 886-0266, <a href="/cdn-cgi/l/email-protection#016560666e7275686f6e2f6a6075696d64646f416471602f666e77"><span class="__cf_email__" data-cfemail="3e5a5f59514d4a57505110555f4a56525b5b507e5b4e5f10595148">[email protected]</span></a>. The EPA Region 5 office is
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
Federal holidays.
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA.
Virtual Public Hearing
EPA is holding a virtual public hearing to provide interested
parties the opportunity to present data, views, or arguments concerning
the proposal. EPA will hold a virtual public hearing to solicit
comments on December 19, 2024. The hearing will convene at 9:00 a.m.
Central Standard Time (CST) and will conclude at 1:00 p.m. CST, or 15
minutes after the last pre-registered presenter in attendance has
presented if there are no additional presenters. EPA will announce
further details, including information on how to register for the
virtual public hearing, on the virtual public hearing website at
<a href="https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn">https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn</a>.
EPA will begin pre-registering presenters and attendees for the
hearing upon publication of this document in the Federal Register. To
pre-register to attend or present at the virtual public hearing, please
use the online registration form available at <a href="https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn">https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn</a>
or contact Mayesha Choudhury at 312-886-5909 or by email at
<a href="/cdn-cgi/l/email-protection#54373c3b21303c21262d7a39352d31273c35143124357a333b22"><span class="__cf_email__" data-cfemail="6102090e1405091413184f0c001804120900210411004f060e17">[email protected]</span></a>. The last day to pre-register to present at
the hearing will be December 16, 2024. On December 16, 2024, EPA will
post a general agenda for the hearing that will list pre-registered
presenters in approximate order at <a href="https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn">https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn</a>.
Additionally, requests to present will be taken on the day of the
hearing as time allows.
EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearing to run either ahead of schedule or behind schedule. Each
commenter will have 5 minutes to provide oral testimony. EPA encourages
commenters to provide EPA with a copy of their oral testimony
electronically by including it in the registration form or emailing it
to <a href="/cdn-cgi/l/email-protection#85e6edeaf0e1edf0f7fcabe8e4fce0f6ede4c5e0f5e4abe2eaf3"><span class="__cf_email__" data-cfemail="42212a2d37262a37303b6c2f233b27312a23022732236c252d34">[email protected]</span></a>. 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 comments and supporting information presented at the virtual
public hearing.
EPA is asking all hearing attendees to pre-register, even those who
do not intend to present. This will help EPA prepare for the virtual
hearing.
Please note that any updates made to any aspect of the hearing will
be posted online at <a href="https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn">https://www.epa.gov/mn/revision-taconite-regional-haze-federal-implementation-plan-mi-and-mn</a>. While EPA expects the
hearing to go forward as set forth above, please monitor our website or
contact Mayesha Choudhury at 312-886-5909 or <a href="/cdn-cgi/l/email-protection#bfdcd7d0cadbd7cacdc691d2dec6daccd7deffdacfde91d8d0c9"><span class="__cf_email__" data-cfemail="5132393e2435392423287f3c302834223930113421307f363e27">[email protected]</span></a>
to determine if there are any updates. EPA does not intend to publish a
document in the Federal Register announcing updates.
If you require the services of a translator or a special
accommodation such as audio description/closed captioning, please pre-
register for the hearing with Mayesha Choudhury at 312-886-5909 or
<a href="/cdn-cgi/l/email-protection#89eae1e6fcede1fcfbf0a7e4e8f0ecfae1e8c9ecf9e8a7eee6ff"><span class="__cf_email__" data-cfemail="ed8e8582988985989f94c3808c94889e858cad889d8cc38a829b">[email protected]</span></a> and describe your needs by December 11, 2024.
EPA may not be able to arrange accommodations without advance notice.
I. Background
A. Requirements of the Clean Air Act and EPA's Regional Haze Rule
In section 169A of the 1977 Amendments to the CAA, Congress created
a program for protecting visibility in the nation's national parks and
wilderness areas. This section of the CAA establishes as a national
goal the ``prevention of any future, and the remedying of any existing,
impairment of visibility in mandatory Class I Federal areas \1\ which
impairment results from manmade air pollution.'' Congress added section
169B to the CAA in 1990 to address regional haze issues. EPA
promulgated a rule to address regional haze on July 1, 1999
[[Page 96154]]
(64 FR 35714), codified at 40 CFR part 51, subpart P (herein after
referred to as the ``Regional Haze Rule''). The Regional Haze Rule
codified and clarified the BART provisions in the CAA and revised the
existing visibility regulations to add provisions addressing regional
haze impairment and to establish a comprehensive visibility protection
program for Class I areas. The requirements for regional haze, found at
40 CFR 51.308 and 51.309, are included in EPA's visibility protection
regulations at 40 CFR part 51, subpart P.
---------------------------------------------------------------------------
\1\ Areas designated as mandatory Class I Federal areas consist
of national parks exceeding 6000 acres, wilderness areas and
national memorial parks exceeding 5000 acres, and all international
parks that were in existence on August 7, 1977. 42 U.S.C. 7472(a).
In accordance with section 169A of the CAA, EPA, in consultation
with the Department of Interior, promulgated a list of 156 areas
where visibility is identified as an important value. 44 FR 69122
(November 30, 1979). The extent of a mandatory Class I area includes
subsequent changes in boundaries, such as park expansions. 42 U.S.C.
7472(a). Although states and Tribes may designate as Class I
additional areas which they consider to have visibility as an
important value, the requirements of the visibility program set
forth in section 169A of the CAA apply only to ``mandatory Class I
Federal areas.'' Each mandatory Class I Federal area is the
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i).
When we use the term ``Class I area'' in this action, we mean a
``mandatory Class I Federal area.''
---------------------------------------------------------------------------
Section 169A of the CAA directs states, or EPA if developing a FIP,
to evaluate the use of retrofit controls at certain larger, often
uncontrolled, older stationary sources to address visibility impacts
from these sources. Specifically, section 169A(b)(2)(A) of the CAA
requires that implementation plans contain such measures as may be
necessary to make reasonable progress toward the natural visibility
goal, including a requirement that certain categories of existing major
stationary sources \2\ built between 1962 and 1977 procure, install,
and operate BART as determined by EPA.
---------------------------------------------------------------------------
\2\ The set of ``major stationary sources'' potentially subject
to BART is listed in CAA section 169A(g)(7) and includes ``taconite
ore processing facilities.''
---------------------------------------------------------------------------
Under the Regional Haze Rule, states (or in the case of a FIP, EPA)
are directed to conduct BART determinations for such ``BART-eligible''
sources that may reasonably be anticipated to cause or contribute to
any visibility impairment in a Class I area.
On July 6, 2005, 70 FR 39104, EPA published the Guidelines for BART
Determinations Under the Regional Haze Rule at appendix Y to 40 CFR
part 51 (hereinafter referred to as the ``BART Guidelines'') to assist
states and EPA in determining which sources should be subject to the
BART requirements and in determining appropriate emission limits for
each source subject to BART.
The process of establishing BART emission limitations follows three
steps. First, states, or EPA if developing a FIP, must identify and
list ``BART-eligible sources.'' \3\ Once the state or EPA has
identified the BART-eligible sources, the second step is to identify
those sources that may ``emit any air pollutant which may reasonably be
anticipated to cause or contribute to any impairment of visibility'' in
a Class I area. (Under the Regional Haze Rule, a source which fits this
description is ``subject to BART.''). Third, for each source subject to
BART, the state or EPA must identify the level of control representing
BART after considering the five factors set forth in CAA section
169A(g). The BART Guidelines provide a process for making BART
determinations that states can use in implementing the BART
requirements on a source-by-source basis. See 40 CFR part 51, appendix
Y, at IV.D.
---------------------------------------------------------------------------
\3\ ``BART-eligible sources'' are those sources that have the
potential to emit 250 tons or more of a visibility-impairing air
pollutant, were not in operation prior to August 7, 1962, but were
in existence on August 7, 1977, and whose operations fall within one
or more of 26 specifically listed source categories. 40 CFR 51.301.
---------------------------------------------------------------------------
States, or EPA if developing a FIP, must address all visibility-
impairing pollutants emitted by a source in the BART determination
process. The most significant visibility impairing pollutants are
SO<INF>2</INF>, NO<INF>X</INF>, and particulate matter (PM).
A state implementation plan (SIP) or FIP addressing regional haze
must include source-specific BART emission limits and compliance
schedules for each source subject to BART. Once a state or EPA has made
a BART determination, the BART controls must be installed and operated
as expeditiously as practicable, but no later than five years after the
date of the final SIP or FIP. See CAA section 169A(g)(4) and 40 CFR
51.308(e)(1)(iv). In addition to what is required by the Regional Haze
Rule, general SIP requirements mandate that the SIP or FIP include all
regulatory requirements related to monitoring, recordkeeping, and
reporting for the BART controls on the source. See CAA section 110(a).
B. BART FIP for Taconite Facilities in Michigan and Minnesota
EPA is proposing to finalize NO<INF>X</INF> and/or SO<INF>2</INF>
limits for the indurating furnaces at five taconite facilities in
accordance with the procedures set forth in the FIP addressing the
requirement for BART at taconite facilities. These facilities include
Tilden Mining Company (Tilden) located at 101 Cci Mine Road, Ishpeming,
Michigan; Hibbing Taconite Company (Hibbing) located at 4950 Highway 5
North, Hibbing, Minnesota; Minorca Mine (Minorca) located at 5950 Old
Highway 53, Virginia, Minnesota; Northshore Mining Company--Silver Bay
(Northshore) located at 10 Outer Drive, Silver Bay, Minnesota, and
United Taconite (UTAC) located at 8470 Townline Road, Forbes,
Minnesota. Tilden, Minorca, Northshore, and UTAC are owned by
Cleveland-Cliffs, Inc. (Cliffs), formerly known as Cliffs Natural
Resources, and Hibbing is jointly owned by Cliffs and United States
Steel. The primary units identified as being subject to BART at Tilden,
Hibbing, Minorca, UTAC, and Northshore include the following
pelletizing, or indurating, furnaces: Tilden Grate Kiln Line 1, Hibbing
Straight-Grate Lines 1-3, Minorca Straight-Grate Line 1, UTAC Grate
Kiln Lines 1 and 2, and Northshore Straight-Grate Furnaces 11 and
12.\4\ The U.S. taconite iron ore industry uses two types of
pelletizing machines or processes: straight-grate kilns and grate
kilns. In a straight-grate kiln, a continuous bed of agglomerated green
pellets is carried through different temperature zones with upward
draft or downward draft blown through the pellets on the metal grate.
The grate kiln system consists of a traveling grate, a rotary kiln, and
an annular cooler. A significant difference between these designs is
that straight-grate kilns do not burn coal and therefore have a much
lower potential for emitting SO<INF>2</INF>. Further, even within the
same kiln type or process, individual furnaces (referred to as
indurating or pelletizing) or processes have distinct equipment and
process characteristics that may affect the compatibility and
performance of certain types of burners.
---------------------------------------------------------------------------
\4\ Fuel sulfur content BART limits were also set for two
process boilers and a line dryer at Tilden. Those limits are not
impacted by this action.
---------------------------------------------------------------------------
On February 6, 2013 (78 FR 8706), EPA promulgated a FIP that set
BART limits for NO<INF>X</INF> and SO<INF>2</INF> emissions from
furnaces at seven taconite facilities in Michigan and Minnesota
(``Original FIP''). EPA took this action because Michigan and Minnesota
had failed to meet a statutory deadline to submit their Regional Haze
SIPs and subsequently failed to require BART at the taconite facilities
within their borders. BART limits for NO<INF>X</INF> were based upon
the performance of high stoichiometric (high-stoich) low-NO<INF>X</INF>
burners (LNBs) \5\ at two of the taconite furnaces at U.S. Steel's
Minntac facility, while BART for SO<INF>2</INF> was established as no
additional controls, apart from a limit on the sulfur content of coal
used in co-firing furnaces.
---------------------------------------------------------------------------
\5\ Stoichiometry refers to the relationship between the actual
quantity of combustion air to the theoretical minimum quantity of
air needed for 100 percent combustion of the fuel.
---------------------------------------------------------------------------
In a related action, EPA published a final partial disapproval of
Michigan's and Minnesota's Regional Haze SIPs on September 30, 2013 (78
FR 59825), due to the states' failure to require BART for taconite
facilities within these states.
ArcelorMittal USA LLC (``ArcelorMittal'') \6\ and Cliffs, owners of
several taconite facilities affected by the FIP, along with the State
of Michigan,
[[Page 96155]]
filed timely petitions for review of the Original FIP. ArcelorMittal
and Cliffs also filed a joint motion seeking a stay of the Original
FIP, which was granted by the Eighth Circuit on June 14, 2013.\7\
ArcelorMittal, Cliffs, the State of Michigan, and others also submitted
petitions for reconsideration of the Original FIP, pursuant to CAA
section 307(d)(7)(B). 42 U.S.C. 7607(d)(7)(B).
---------------------------------------------------------------------------
\6\ Cliffs acquired ArcelorMittal Steel Production Company in
2020. Previously, Minorca was owned by ArcelorMittal and Hibbing was
jointly owned by ArcelorMittal, Cliffs and United States Steel.
Currently, Minorca is owned by Cliffs and Hibbing is jointly owned
by Cliffs and United States Steel.
\7\ On November 15, 2016, the 8th Circuit Court of Appeals
terminated the June 14, 2013, stay and extended the deadlines in the
Original FIP by one day for each day the court's stay was in place.
From the day the 2013 FIP was effective to the day it was stayed, 98
days elapsed (March 8, 2013, to June 14, 2013). See Order dated
November 15, 2016, in response to U.S. EPA's Petition to reconsider
the Original FIP, EPA-R05OAR-2017-0066-0009 (8th Cir. 2016). As a
result, the deadlines contained in the Original FIP still apply
(e.g., 6 months after March 8, 2013), only now from the date the
stay was terminated, minus the number of days that elapsed prior to
the stay being issued.
---------------------------------------------------------------------------
On October 22, 2015 (80 FR 64160), in response to the petitions for
reconsideration and due to new information submitted to EPA after
promulgation of the Original FIP, EPA proposed to revise the Original
FIP to revise NO<INF>X</INF> and SO<INF>2</INF> emission limits for
certain taconite facilities. On April 16, 2016 (81 FR 21672), EPA
promulgated the final 2016 revised FIP (``2016 FIP''). With respect to
NO<INF>X</INF>, the emission limits in the 2016 FIP were based on
information submitted to EPA by Cliffs and ArcelorMittal that suggested
high-stoich LNBs, which formed the basis for the NO<INF>X</INF> limits
in the Original FIP, posed serious technical hurdles. In the 2016 FIP,
EPA revised the NO<INF>X</INF> emission limits for Tilden, Hibbing,
Minorca, and UTAC, and set forth a process to confirm or modify those
emission limits using continuous emissions monitoring system (CEMS)
data that was to be collected after the installation of the selected
low-NO<INF>X</INF> technology. Under the 2016 FIP, the NO<INF>X</INF>
emission limits do not become enforceable until EPA confirms or
modifies the emission limits in accordance with procedures set forth in
the FIP. The NO<INF>X</INF> emission limits in the 2016 FIP were based
upon low-stoich LNBs (for grate kilns) and LNBs that utilize a
combination of water and steam injection and pre-combustion
technologies (for straight-grate kilns).
With respect to SO<INF>2</INF>, EPA granted reconsideration of the
SO<INF>2</INF> limit for Tilden's grate kiln due to information that
became available after the close of the public comment period on the
2013 FIP regarding Tilden's intent to burn mixed fuels. Cliffs' intent
to burn mixed fuels at Tilden was not considered in the Original FIP
and would have led to an inability to meet the established BART limit.
The 2016 FIP limits the sulfur content of the coal combusted on Tilden
Line 1 and sets an SO<INF>2</INF> emission limit for the furnace.
Cliffs and ArcelorMittal filed petitions for review of the 2016 FIP
due to a dispute over the UPL equation in the final rule. The 2016 FIP
requirements for each facility are set forth in 40 CFR 52.1183 for
Michigan and 40 CFR 52.1235 for Minnesota and discussed further in the
remainder of this action.
II. Basis for NOX Limits
The 2016 FIP set emission limits in pounds (lbs) of NO<INF>X</INF>
per million British Thermal Unit (MMBtu), based on a 30-day (720-hour)
rolling average, and established a process to either confirm or modify
the NO<INF>X</INF> emission limits within established ranges based on
CEMS data that Tilden, Hibbing, Minorca, and UTAC were required to
submit to EPA by dates specified in the 2016 FIP.\8\ The FIP also
specified that the NO<INF>X</INF> emission limits for these facilities
would become enforceable only after EPA's confirmation or modification
of the NO<INF>X</INF> emission limits reflecting EPA's expectation that
the owner or operator of each facility would provide the requisite data
to EPA by the dates specified in the FIP. EPA's efforts to finalize
NO<INF>X</INF> emission limits for these facilities by the deadlines
established in the FIP were complicated by several implementation
issues, including challenges with installation of control technology,
delays in receipt of requisite data, and emission limit modification
requests not conforming to the requirements set forth in the FIP.
---------------------------------------------------------------------------
\8\ Taconite facilities typically operate 24 hours per day and
720 is the number of hours in a 30-day period; therefore, a 720-hour
average is essentially equivalent to a 30-day average.
---------------------------------------------------------------------------
The NO<INF>X</INF> emission limits established for each furnace and
the ranges of limits allowable under the limit modification process are
set forth in Table 1. As indicated in Table 1, the emission limits for
certain furnaces vary by the type of fuel being used (natural gas or
``co-fire,'' which is a combination of natural gas and coal).
Table 1--NOX Limits and Limit Modification Ranges Established in the
2016 FIP
------------------------------------------------------------------------
Emission limit
Furnace Emission limit (lbs modification range
NOX/MMBtu) (lbs NOX/MMBtu)
------------------------------------------------------------------------
Tilden Line 1:
Natural Gas............. 2.8 2.8-3.0
Co-fire................. 1.5 1.5-2.5
Hibbing Line 1.............. 1.2 1.2-1.8
Hibbing Line 2.............. 1.2 1.2-1.8
Hibbing Line 3.............. 1.2 1.2-1.8
Minorca................. 1.2 1.2-1.8
UTAC Line 1:
Natural Gas............. 2.8 2.8-3.0
Co-fire................. 1.5 1.5-2.5
UTAC Line 2:
Natural Gas............. 2.8 2.8-3.0
Co-fire................. 1.5 1.5-2.5
------------------------------------------------------------------------
For Tilden, Hibbing, Minorca, and UTAC, the process specified in
the 2016 FIP to either confirm or modify the NO<INF>X</INF> emission
limits within the established ranges included the installation of a
CEMS, submission of an engineering report to EPA, installation of
NO<INF>X</INF> reduction control technology, submission of pellet
quality analyses to EPA, and submission to EPA of a report to either
confirm or modify the limit. For any furnace without CEMS already
installed, CEMS installation was required for each furnace by 6 months
after May 12, 2016, and the owner or operator was required to submit
quarterly CEMS data to EPA after May 12, 2016, for the time periods
specified
[[Page 96156]]
below in Table 2. Engineering reports containing detailed engineering
analyses and modeling of the selected NO<INF>X</INF> reduction
technology for each furnace demonstrating that the technology was
designed to meet an emission limit equal to the lower bound of the
established range were required to be submitted to EPA by the deadlines
specified in Table 2. NO<INF>X</INF> reduction technology was required
to be installed two months after the engineering report submission
deadline. Beginning on the earlier of six months after the installation
of NO<INF>X</INF> reduction technology or the deadline for installation
of the NO<INF>X</INF> reduction technology, the owner or operator was
required to submit quarterly pellet quality analyses to EPA, including
an explanation of causes for pellet samples that failed to meet the
acceptable range for any pellet quality analysis factor, for the time
periods specified in Table 2. At the end of the CEMS and pellet quality
data collection periods, the owner or operator of each furnace may
submit a report to EPA to either confirm or modify the NO<INF>X</INF>
limits within the bounds described in the 2016 FIP (and above in this
section). The 2016 FIP also allows the owner or operator to submit a
report proposing a single NO<INF>X</INF> limit for all fuels. The
process for confirming or modifying limits detailed in the 2016 FIP
specifies that EPA's determinations shall be based on the appropriate
UPL equation, using CEMS data that meet pellet quality specifications
and proper furnace/burner operation. For a more detailed description of
the process set forth in the 2016 FIP to confirm or modify the emission
limits, see 40 CFR 52.1183 and 40 CFR 52.1235.
Table 2--Timelines of Processes To Confirm or Modify Limits
----------------------------------------------------------------------------------------------------------------
Period of
Period of CEMS NOX reduction pellet Report to
data required Engineering technology quality data confirm or
Furnace for report installation required for modify limit
submission to deadline deadline submission to deadline
EPA EPA *
----------------------------------------------------------------------------------------------------------------
Months after May 12, 2016
-------------------------------------------------------------------------------
Tilden Line 1................... 0-57 48 50 50-57 57
Hibbing Line 1.................. 6-34 24 26 26-34 34
Hibbing Line 2.................. 6-52 42 44 44-52 52
Hibbing Line 3.................. 6-57 48 50 50-57 57
Minorca's Indurating Furnace.... 6-52 42 44 44-52 52
UTAC Line 1..................... 0-34 24 26 26-34 34
UTAC Line 2..................... 0-52 42 44 44-52 52
----------------------------------------------------------------------------------------------------------------
* If the owner or operator installed NOX reduction technology more than six months before the required date,
pellet quality analyses were required to be submitted to EPA beginning six months after installation.
The 2016 FIP incorporates two UPL equations to calculate emission
limits. The appropriate equation is determined by the statistical
distribution of the hourly CEMS data. If the data are normally
distributed and statistically independent, the equation in 40 CFR
52.1183(p)(1) and 40 CFR 52.1235(f)(1) is used. If the data are not
normally distributed or are normally distributed but not statistically
independent, the non-parametric equation in 40 CFR 52.1183(p)(2) and 40
CFR 52.1235(f)(2) is used. None of the CEMS data submitted are normally
distributed and statistically independent, therefore the non-parametric
equation is the applicable equation for all limit setting in this
action.\9\
---------------------------------------------------------------------------
\9\ Data distribution analyses are available in the docket for
this action.
---------------------------------------------------------------------------
The non-parametric equation in the 2016 FIP calculates a 95th
percentile UPL by ranking 720-hour averages of NO<INF>X</INF> emissions
in lbs/MMBtu from lowest to highest and identifying the value at the
95th percentile of the data set as the UPL and emission limit.\10\
While a 95th percentile UPL establishes an emission rate that a source
is predicted to be below during at least 95 out of 100 averaging
periods, it was not EPA's intent to set a limit that a source would be
expected to exceed five percent of the time once the limit was in
place. Rather, EPA used the 95th percentile UPL to ensure that the
final emission limits would be consistent with the actual emission
reduction capabilities of the BART controls, as required by 40 CFR
51.301, which defines BART as ``the degree of reduction achievable.''
\11\ EPA expected that during the eight-month CEMS data collection
period, furnace operators would be adjusting numerous variables to
optimize control technology performance, which would result in higher
emissions at times during the initial ``shakedown'' period. Once the
eight-month data collection period was over, EPA expected that the
operators would have gained sufficient experience to run the furnaces
and control technologies with fewer adjustments, meaning less emission
variations and lower emissions overall. EPA selected the 95th
percentile UPL to ensure the elevated emissions expected during the
initial shakedown period would not become the basis for final emission
limits.
---------------------------------------------------------------------------
\10\ Taconite facilities typically operate 24 hours per day and
720 is the number of hours in a 30-day period; therefore, a 720-hour
average is essentially equivalent to a 30-day average. For
facilities that both burn natural gas exclusively and co-fire with
coal, i.e., Tilden and UTAC, a 30-day period may involve operation
with only natural gas as well as operation with co-firing of coal.
Therefore, the 2016 FIP established UPL equations based on 720-hour
averages to allow for the separation of hours when burning only
natural gas from hours when co-firing with coal. When calculating an
emission limit that applies only when burning natural gas, emissions
are averaged over 720 successive hours in which the unit burns only
natural gas. When calculating a co-firing emission limit, emissions
are averaged over 720 successive hours in which the unit burns a
gas/coal mix. All emission limit modifications were calculated based
on 720-hour averages, consistent with the equations at 40 CFR
52.1183(p) and 40 CFR 52.1235(f). However, EPA is proposing modified
emission limits in the form of a 30-day average if the facility
burns only one fuel or if the modified limit applies to all fuels.
In those circumstances, there is no need to be able to separate the
hourly data to determine compliance with the emission limit.
\11\ April 16, 2016, 81 FR 21672, 21680.
---------------------------------------------------------------------------
However, once continuous data collection began, the CEMS data did
not show the expected elevated emissions levels during the shakedown
period and emissions were not consistently lower toward the end of the
data collection period as compared to the beginning of the period.\12\
Therefore, EPA has
[[Page 96157]]
determined that using the UPL equation at the 99th percentile is more
appropriate to establish an emission limit consistent with the actual
emission reduction capabilities of the BART controls and is proposing
to modify the UPL equations used to calculate both the NO<INF>X</INF>
and SO<INF>2</INF> emission limits to reflect use of the 99th
percentile. The emission limits EPA is proposing in this action were
calculated using the UPL equations at 40 CFR 52.1183(p) and 40 CFR
52.1235(f) at the 99th percentile.\13\
---------------------------------------------------------------------------
\12\ See emission limit calculation files in the docket for this
action.
\13\ Data analyses and emissions calculations are available in
the docket for this action.
---------------------------------------------------------------------------
A. Tilden
For Tilden's indurating furnace, Tilden Line 1 (EUKILN1), the 2016
FIP established a specific NO<INF>X</INF> BART emission limit of 2.8
pounds of NO<INF>X</INF>/MMBtu when burning natural gas, while allowing
for potential modification of the limit within the range of 2.8-3.0 lbs
NO<INF>X</INF>/MMBtu. Similarly, the 2016 FIP established a specific
NO<INF>X</INF> BART emission limit of 1.5 lbs NO<INF>X</INF>/MMBtu when
co-firing coal and natural gas, with an allowance for potential
modification of the limit within the range of 1.5-2.5 lbs
NO<INF>X</INF>/MMBtu.\14\ The 2016 FIP also allowed for the
establishment of a single NO<INF>X</INF> limit for all fuels.\15\
---------------------------------------------------------------------------
\14\ 40 CFR 52.1183(k)(1).
\15\ 40 CFR 52.1183(k)(1)(viii).
---------------------------------------------------------------------------
Tilden submitted a partially complete engineering report on May 21,
2020, and submitted the final engineering report on July 30, 2020.
Tilden implemented low-stoichiometry LNBs designed to achieve an
emission rate of 2.8 lbs NO<INF>X</INF>/MMBtu when firing exclusively
natural gas and 1.5 lbs NO<INF>X</INF>/MMBtu when co-firing with coal,
as described in the engineering report submitted to EPA.
On February 12, 2021, Tilden submitted a report requesting
modification of the NO<INF>X</INF> limits for Line 1 pursuant to 40 CFR
52.1183 (k)(1)(vi). Tilden requested an emission limit of 3.0 lbs
NO<INF>X</INF>/MMBtu for all fuels. Tilden's limit modification request
was accompanied by CEMS data (in 30-day rolling averages) from
September 12, 2020, to February 2, 2021. On May 21, 2021, Tilden
provided hourly emission data for July 1, 2020, to February 11, 2021.
Approximately half of these data were collected when Tilden was co-
firing with coal and half were collected when Tilden was burning
exclusively natural gas. Tilden demonstrated that when burning natural
gas, NO<INF>X</INF> emission rates recorded were higher than the
modeling results presented in the engineering report, and above the
high end of the limit range established in the 2016 FIP (2.8-3.0 lbs/
MMBtu). The CEMS data submitted to EPA when burning coal recorded
emission rates within the range specified in the 2016 FIP (1.5-2.5 lbs/
MMBtu). Tilden explained that the furnace is unable to achieve 3.0 lbs
NO<INF>X</INF>/MMBtu when burning exclusively natural gas and would
need to burn a minimum of 80% coal when co-firing to meet a limit of
2.0 lbs NO<INF>X</INF>/MMBtu. Tilden stated a preference to maximize
natural gas usage and supplement with solid fuel as needed to meet
NO<INF>X</INF> limits.\16\
---------------------------------------------------------------------------
\16\ See ``Tilden NO<INF>X</INF> limit modification report (Feb.
12, 2021)_Redacted.pdf,'' available in the docket for this action.
---------------------------------------------------------------------------
The 2016 FIP provides Tilden the option to propose, for EPA's
consideration and approval, a single NO<INF>X</INF> emission limit for
all fuels based on a 30-day rolling average. Citing the CEMS data,
Tilden requested a revised NO<INF>X</INF> BART limit of 3.0 lbs
NO<INF>X</INF>/MMBtu for all fuels that would apply on a rolling 30-day
average, contending that this emission limit is the most stringent
limit that can be met without substantial increases in coal usage,
while maintaining pellet quality standards.
Based on the equation set forth at 40 CFR 52.1183(p)(2), EPA
calculated a 720-hour average NO<INF>X</INF> emission limit of 3.8 lbs
NO<INF>X</INF>/MMBtu when burning exclusively natural gas, and
separately, an emission limit of 1.9 lbs NO<INF>X</INF>/MMBtu when
burning mixed fuel.\17\ While CEMS data show the installed emission
control measures reduced NO<INF>X</INF> emissions, the selected
technology failed to achieve emission rates within the specified FIP
ranges when burning only natural gas (2.8-3.0 lbs NO<INF>X</INF>/
MMBtu). Using the non-parametric equation with the full data set,
unseparated by fuel type, EPA calculated a 720-hour average UPL of 3.7
lbs NO<INF>X</INF>/MMBtu. EPA evaluated these CEMS data and considered
Tilden's requested single NO<INF>X</INF> emission limit of 3.0 lbs
NO<INF>X</INF>/MMBtu for all fuels based on a 30-day rolling average,
as allowed at 40 CFR 52.1183(k)(1)(viii). EPA has concluded that
Tilden's requested emission limit of 3.0 lbs NO<INF>X</INF>/MMBtu for
all fuels based on a 30-day rolling average is appropriate and reflects
BART. It allows Tilden to select a fuel mix that maximizes natural gas
usage and minimizes coal usage if the facility so chooses without
exceeding the natural gas emission limit range established in the 2016
FIP. This has the duel environmental (visibility) benefit of minimizing
NO<INF>X</INF> emissions by setting an emissions limit that is below
the calculated natural gas-only rate, and also potentially minimizing
the use of coal and the associated SO<INF>2</INF> emissions from coal
burning. Therefore, based on these data and as provided at 40 CFR
52.1183(k)(1)(viii), EPA is proposing that a modified limit of 3.0 lbs
NO<INF>X</INF>/MMBtu for all fuels, with compliance to be determined on
a rolling 30-day average basis, reflects BART for the Tilden Line 1
indurating furnace.
---------------------------------------------------------------------------
\17\ See Tilden Emission Limit Calculations, available in the
docket for this action.
---------------------------------------------------------------------------
B. Hibbing
For Hibbing Lines 1, 2, and 3, the 2016 FIP established
NO<INF>X</INF> BART emission limits of 1.2 lbs NO<INF>X</INF>/MMBtu
that applied to each furnace individually, with provisions allowing for
potential modification of the limits within the range of 1.2-1.8 lbs
NO<INF>X</INF>/MMBtu.\18\
---------------------------------------------------------------------------
\18\ See 40 CFR 52.1235((b)(1)(ii).
---------------------------------------------------------------------------
Hibbing implemented the NO<INF>X</INF> reduction measures described
in its engineering report, submitted to EPA on May 11, 2018, identified
as LNBs in conjunction with water injection, at Hibbing Lines 1, 2, and
3. Hibbing installed CEMS on Lines 1, 2, and 3 and provided EPA with
hourly NO<INF>X</INF> emissions data on March 12, 2019, September 11,
2020, and February 12, 2021, for Lines 1, 2 and 3, respectively,
documenting actual emissions after installation of LNB technology.
Hibbing's submittals included CEMS data from July 12, 2018, to March
11, 2019, for Line 1; January 12, 2020, through September 1, 2020, for
Line 2; and August 3, 2020, to February 11, 2021, for Line 3. The
hourly CEMS data identified hours excluded from the limit-setting
calculations because pellets failed to meet pellet quality
specifications. Although the limit-setting period for Line 3
established in the 2016 FIP began August 3, 2020, Line 3 did not
operate during the period between July 12 to August 3, 2020, due to
COVID-related reasons. Line 2 did not operate from May 1, 2020, to July
31, 2020, during the limit setting period for similar reasons. On
November 25, 2020, Hibbing provided additional information requested by
EPA, including hourly CEMS data for Lines 1, 2, and 3 in Excel format
to facilitate independent calculation of emission limits and
identification of hours when the burner was not operated within the
parameters modeled in the engineering report.
The requirements at 40 CFR 52.1235((b)(1)(ii)(A)(6), (B)(6), and
(C)(6) set forth the process for submitting data to support limit
modifications under the 2016 FIP. At the time of the initial
[[Page 96158]]
CEMS data submissions, Hibbing requested NO<INF>X</INF> emission limits
of 1.7, 1.5, and 1.6 lbs NO<INF>X</INF>/MMBtu on Lines 1, 2, and 3,
respectively. The facility cited sub-zero temperatures and other
factors that may have affected the calculated emission rates and
restricted production. Further, Hibbing provided regression analyses
assessing the relationship between furnace feed rates and
NO<INF>X</INF> emission rates during the limit-setting periods to
support the requested limit increases.
On October 22, 2021, Hibbing submitted a request to EPA to
establish a crossline average emission limit for Lines 1, 2, and 3 of
1.6 lbs NO<INF>X</INF>/MMBtu, with compliance to be determined on a 30-
day rolling average basis. The submittal included hourly CEMS data for
the same time periods as Hibbing's initial limit modification
submittals and a regression analysis assessing the relationship between
furnace feed rates and NO<INF>X</INF> emission rates during the limit-
setting periods to support the requested limit increases. The hourly
CEMS data submitted to EPA included a description of the failure
analyses identifying potential reasons for pellets failing to meet
pellet quality specifications for hours excluded in the limit-setting
calculation.
There is no basis in the FIP for adjusting emission limits to
account for possible future production levels based upon an assumed
correlation between feed rates and emissions. Therefore, in accordance
with 40 CFR 52.1235(f)(2), EPA calculated 720-hour average
NO<INF>X</INF> emission limits of 1.5 lbs NO<INF>X</INF>/MMBtu for Line
1, 1.4 lbs NO<INF>X</INF>/MMBtu for Line 2, and 1.5 lbs NO<INF>X</INF>/
MMBtu for Line 3.\19\ Under the BART Guidelines, a source may be
permitted to `` `average' emissions across any set of BART-eligible
emission units within a fenceline, so long as the emission reductions
from each pollutant being controlled for BART would be equal to those
reductions that would be obtained by simply controlling each of the
BART-eligible units that constitute BART-eligible sources.'' \20\ EPA
averaged the single line limits described above and calculated a
crossline 720-hour average emission limit of 1.5 lbs NO<INF>X</INF>/
MMBtu. The NO<INF>X</INF> controls have been installed and are being
operated on all three lines. Based on EPA's analysis, this crossline
average emission limit is equal to the reductions that would be
obtained by controlling each line separately. Therefore, based on these
data and as provided at 40 CFR 52.12335(b)(1)(ii)(A)(7), (B)(7), and
(C)(7), and consistent with 40 CFR 51.308(e) and 40 CFR part 51,
appendix Y, at V, EPA is proposing that a crossline average emission
limit of 1.5 lbs NO<INF>X</INF>/MMBtu for Hibbing Lines 1, 2, and 3,
with compliance to be determined on a 30-day rolling average basis,
reflects NO<INF>X</INF> BART for Hibbing Lines 1, 2, and 3.
---------------------------------------------------------------------------
\19\ See Hibbing Emission Limit Calculations, available in the
docket for this action.
\20\ 40 CFR part 51, appendix Y, at V.
---------------------------------------------------------------------------
C. Minorca
For Minorca's indurating furnace, the 2016 FIP established a
NO<INF>X</INF> BART emission limit of 1.2 lbs NO<INF>X</INF>/MMBtu,
while allowing for potential modification of the limit within the range
of 1.2-1.8 lbs NO<INF>X</INF>/MMBtu.\21\
---------------------------------------------------------------------------
\21\ See 40 CFR 52.1235((b)(1)(v).
---------------------------------------------------------------------------
On November 12, 2019, Minorca submitted an engineering report to
EPA which identified the low NO<INF>X</INF> technology to be installed
on Line 1 as an LNB, water injection, and utilization of specific
operating parameters. The combined use of these measures was projected
to meet an emission limit of 1.2 lbs NO<INF>X</INF>/MMBtu based on a
30-day average. On September 11, 2020, Minorca submitted CEMS data for
the period January 12, 2020, to September 10, 2020, excluding the CEMS
values that did not meet pellet quality specifications, consistent with
the 2016 FIP.\22\
---------------------------------------------------------------------------
\22\ CEMS data in the September 11, 2020, submittal was
presented as 720-hour rolling averages. On November 25, 2020,
Minorca provided the hourly CEMS data for the same January 12, 2020,
to September 10, 2020, time period to allow for independent
calculation of 720-hour averages.
---------------------------------------------------------------------------
On October 22, 2021, Minorca submitted supplemental information
consisting of 720-hour averages of CEMS data from January 12, 2020,
through September 30, 2021. Adding the data from September 10, 2020,
through September 30, 2021, to the original data set, Minorca
calculated an emission limit of 1.6 lbs NO<INF>X</INF>/MMBtu using the
equation at 40 CFR 52.1235(f)(2). Minorca then performed a regression
analysis assessing the relationship between furnace pellet production
rates and NO<INF>X</INF> emission rates during the limit-setting period
to support the requested limit increase. Minorca cited the climate in
Minnesota and other factors that may have affected production rates in
its explanation of why the emission limit should be adjusted to 1.7 lbs
NO<INF>X</INF>/MMBtu.
Based on the non-parametric equation at 40 CFR 52.1235(f)(2), EPA
evaluated the 720-hour average NO<INF>X</INF> emission data for the
full data set submitted and calculated an emission limit of 1.6 lbs
NO<INF>X</INF>/MMBtu.\23\ There is no basis in the FIP for adjusting
emission limits to account for possible future production levels based
upon an assumed correlation between feed rates and emissions.
Therefore, based on these data and as provided at 40 CFR
52.1235(b)(1)(v)(7), EPA is proposing that a modified limit of 1.6 lbs
NO<INF>X</INF>/MMBtu, with compliance to be determined on a rolling 30-
day average basis, reflects BART for the Minorca Line 1 indurating
furnace.
---------------------------------------------------------------------------
\23\ See Minorca Emission Limit Calculations, available in the
docket for this action.
---------------------------------------------------------------------------
D. UTAC
For UTAC's indurating furnaces, Grate Kiln Line 1 (EU040) and Grate
Kiln Line 2 (EU042), the 2016 FIP established specific NO<INF>X</INF>
BART limits of 2.8 pounds of NO<INF>X</INF>/MMBtu when burning natural
gas, while allowing for potential modification of the limits within the
range of 2.8-3.0 lbs NO<INF>X</INF>/MMBtu. Similarly, the 2016 FIP
established specific NO<INF>X</INF> BART limits of 1.5 lbs
NO<INF>X</INF>/MMBtu when co-firing coal and natural gas, while
allowing for potential modification of the limits within the range of
1.5-2.5 lbs NO<INF>X</INF>/MMBtu.\24\ The 2016 FIP also allowed for the
establishment of a single NO<INF>X</INF> limit for all fuels.
---------------------------------------------------------------------------
\24\ 40 CFR 52.1235(b)(1)(iv).
---------------------------------------------------------------------------
UTAC submitted an engineering report for Line 1 on May 11, 2018.
UTAC installed and began operating the sub-stoichiometric staged
combustion LNB designed to achieve an emission rate of 2.8 lbs
NO<INF>X</INF>/MMBtu when firing exclusively natural gas and 1.5 lbs
NO<INF>X</INF>/MMBtu when co-firing with coal, as described in the
engineering report submitted to EPA. UTAC subsequently made
modifications to the Line 1 LNB in September 2018. On March 12, 2019,
UTAC submitted a report requesting modification of the co-firing
NO<INF>X</INF> limit for Line 1 to 2.5 lbs NO<INF>X</INF>/MMBtu, based
upon 720-hour averages from February 2019.
On November 12, 2019, UTAC submitted a report to EPA to address the
requirement for an engineering report for Line 2. On November 12, 2021,
UTAC submitted information on the LNB selected for Line 2, a modified
version of the LNB installed on Line 1. This submittal included a
report on computational fluid dynamics modeling demonstrating the
burner was designed to achieve an emission rate of 2.8 lbs
NO<INF>X</INF>/MMBtu when firing exclusively natural gas and 1.5 lbs
NO<INF>X</INF>/MMBtu when co-firing with coal. On April 11, 2023, UTAC
submitted an analysis of Line 1 and Line 2 NO<INF>X</INF> performance
[[Page 96159]]
post LNB installations and requested a crossline average limit of 3.0
lb NO<INF>X</INF>/MMBtu for all fuels, based on a 30-day rolling
average. Along with the analysis, UTAC submitted 720-hour averages of
total lbs NO<INF>X</INF>/MMBtu for Lines 1 and 2 combined for the time
period of January 25, 2022, to March 26, 2023. UTAC also submitted
hourly CEMS and process information for this time period, which UTAC
claimed as confidential business information, so that EPA could verify
the calculations.
Based on the equation set forth at 40 CFR 52.1235(f)(2), EPA
calculated 720-hour average NO<INF>X</INF> emission limits of 2.3 lbs
NO<INF>X</INF>/MMBtu and 3.6 lbs NO<INF>X</INF>/MMBtu when burning
exclusively natural gas for Lines 1 and 2, respectively. Separately,
EPA calculated an emission limit of 3.1 lbs NO<INF>X</INF>/MMBtu when
burning mixed fuel on Line 2. There were 475 hours of co-firing data
for Line 1, which is not sufficient to calculate a 720-hour average
NO<INF>X</INF> emission limit. EPA also calculated an emission limit of
3.1 lbs NO<INF>X</INF>/MMBtu when combining hourly emissions data for
both lines and all fuels.\25\ While CEMS data show the installed
emission control measures reduced NO<INF>X</INF> emissions, the
selected technology failed to achieve emission rates within the
specified FIP ranges, particularly when evaluating separate limits for
each fuel type.
---------------------------------------------------------------------------
\25\ See United Taconite Emission Limit Calculations, available
in the docket for this action.
---------------------------------------------------------------------------
As discussed in II.B., under the BART Guidelines, a source may be
permitted to `` `average' emissions across any set of BART-eligible
emission units within a fenceline, so long as the emission reductions
from each pollutant being controlled for BART would be equal to those
reductions that would be obtained by simply controlling each of the
BART-eligible units that constitute BART-eligible sources.'' \26\ EPA
evaluated the CEMS data and considered UTAC's requested crossline
average NO<INF>X</INF> emission limit of 3.0 lbs NO<INF>X</INF>/MMBtu
for all fuels, for Lines 1 and 2, with compliance to be determined on a
30-day rolling average basis. Based on EPA's analysis, this crossline
average emission limit is equal to the reductions that would be
obtained by controlling each line separately and is within the natural
gas NO<INF>X</INF> emission limit range established in the 2016 FIP. A
single fuel-neutral emission limit allows UTAC to select a fuel mix
that maximizes natural gas usage and minimizes coal usage without
exceeding the natural gas emission limit range established in the 2016
FIP. This has the dual environmental (visibility) benefit of minimizing
NO<INF>X</INF> emissions by setting an emissions limit that is below
the calculated natural gas-only rate, and also potentially minimizing
the use of coal and the associated SO<INF>2</INF> emissions from
burning coal. Therefore, based on these data and as provided at 40 CFR
52.1235(b)(1)(iv)(A)(8) and (B)(8), and consistent with 40 CFR
51.308(e) and 40 CFR part 51, appendix Y, at V, EPA is proposing that a
crossline emission limit of 3.0 lbs NO<INF>X</INF>/MMBtu for all fuels
for UTAC Lines 1 and 2, based on a rolling 30-day average, reflects
BART for UTAC Lines 1 and 2.
---------------------------------------------------------------------------
\26\ 40 CFR part 51, appendix Y, at V.
---------------------------------------------------------------------------
III. Basis for SO2 Limits
As previously described, the Original FIP determined that existing
controls reflected SO<INF>2</INF> BART for Minorca, Hibbing, and
Northshore, and established SO<INF>2</INF> emission limits for each
furnace, with the option or requirement, depending on the facility,
that the owner or operator submit one year of CEMS data to EPA to set a
revised SO<INF>2</INF> emission limit calculated using the appropriate
UPL equation. The 2016 FIP limited the sulfur content of the coal
burned at Tilden, set an SO<INF>2</INF> emission limit, and required
Tilden to submit one year of CEMS data to EPA to set a revised
SO<INF>2</INF> emission limit calculated using the appropriate UPL
equation. For a more detailed description of the existing
SO<INF>2</INF> emission limits and the process set forth to modify the
emission limits, see 40 CFR 52.1235 (Hibbing, Minorca, and Northshore)
and 40 CFR 52.1183 (Tilden). As discussed above in II., EPA has
calculated the emission limits using the appropriate UPL equation at
the 99th percentile.
A. Tilden
For Tilden, the 2016 FIP established a specific SO<INF>2</INF> BART
emission limit of 500 pounds of SO<INF>2</INF> per hour (lbs/hr) for
Grate Kiln Line 1, with no more than 0.60 percent sulfur by weight
based on a monthly block average for any coal usage. The 2016 FIP also
required that the owner or operator of Tilden calculate an
SO<INF>2</INF> emission limit based on one year of hourly CEMS
emissions data using the appropriate UPL equation provided in 40 CFR
52.1183(p) and submit such calculations and data to EPA by 36 months
after May 12, 2016. The 2016 FIP provides that EPA may revise the
emission limit downward to reflect the calculated SO<INF>2</INF>
emission rate; however, EPA may not increase the SO<INF>2</INF> limit
above 500 lbs SO<INF>2</INF>/hr.
On October 1, 2018, Tilden submitted SO<INF>2</INF> emissions data
to EPA reflecting Tilden burning exclusively natural gas during the
period March 28, 2017, through March 27, 2018. Citing various
production-related concerns, Tilden adjusted its calculated limit to
account for expected higher production capacity and higher ore sulfur
content, which resulted in an adjusted expected emission rate of 568
lbs SO<INF>2</INF>/hr. Tilden requested an SO<INF>2</INF> emission
limit of 500 lbs/hour for all fuels, regardless of natural gas or coal
fuel usage, as established in the 2016 FIP. On November 10, 2022,
Tilden submitted hourly SO<INF>2</INF> data for Line 1 from the same
time period of March 28, 2017, through March 27, 2018, during which
time Tilden was exclusively burning natural gas. On March 1, 2023,
Tilden provided hourly co-firing CEMS data for July 12, 2018, through
July 11, 2019. On March 30, 2023, Tilden provided hourly CEMS data for
the time period March 27, 2018, through March 26, 2019, which included
both co-firing and natural gas-only operation.
The 2016 FIP established a single SO<INF>2</INF> emission limit to
apply regardless of natural gas or coal fuel usage, which Tilden must
meet at all times. Consistent with this approach, and because
SO<INF>2</INF> emissions are higher when Tilden is co-firing and the
emission limit must be met at all times, EPA is proposing to base the
emission limit modification calculations on all co-firing data included
in Tilden's March 1, 2023, and March 30, 2023, CEMS data submissions.
Based on the equation set forth at 40 CFR 52.1183(p)(2), EPA calculated
an emission limit of 189 lbs SO<INF>2</INF>/hour consistent with this
approach.\27\ There is no basis in the FIP for adjusting emission
limits to account for possible future production levels or possible
higher ore sulfur content. Therefore, based on these data and as
provided at 40 CFR 52.1183(k)(3), EPA is proposing that an
SO<INF>2</INF> limit of 189 lbs SO<INF>2</INF>/hr for the Tilden Line 1
indurating furnace, with compliance to be determined on a 30-day
rolling average basis, reflects SO<INF>2</INF> BART for Tilden Line 1.
---------------------------------------------------------------------------
\27\ See Tilden Emission Limit Calculations, available in the
docket for this action.
---------------------------------------------------------------------------
B. Hibbing
For Hibbing Lines 1, 2, and 3, the Original FIP set an aggregate
emission limit of 247.8 lbs SO<INF>2</INF>/hr, based on a 30-day
rolling average and excluding emissions resulting from the combustion
of fuel oil, and provided Hibbing the option of calculating a revised
SO<INF>2</INF> emission limit by 20 months after March 8, 2013, based
on one year of hourly CEMS emissions data and the non-parametric UPL
equation. If any fuel oil is burned after the first day
[[Page 96160]]
that SO<INF>2</INF> CEMS were required to be operational, the 2016 FIP
requires Hibbing to submit the gallons of fuel oil burned per hour, the
sulfur content of the fuel oil, and the SO<INF>2</INF> emissions in
pounds per hour, so that EPA can establish an SO<INF>2</INF> emissions
limit for fuel oil. Hibbing chose not to calculate a revised
SO<INF>2</INF> emission limit.\28\
---------------------------------------------------------------------------
\28\ While Hibbing's SO<INF>2</INF> BART limit is not being
modified, the regulatory text at 40 CFR 52.1235(b)(2)(ii) is being
revised to remove the original limit modification provisions and
clarify that Hibbing's SO<INF>2</INF> BART limit is final.
---------------------------------------------------------------------------
C. Minorca
For Minorca, the Original FIP set an emission limit of 38.16 lbs
SO<INF>2</INF>/hour, based on a 30-day rolling average and excluding
emissions when Minorca is combusting fuel oil, with an allowance for
potential modification of the limit based on one year of hourly CEMS
data submitted to EPA by 20 months after March 8, 2013. If any fuel oil
is burned after the first day that SO<INF>2</INF> CEMS were required to
be operational, the 2016 FIP requires Minorca to submit the gallons of
fuel oil burned per hour, the sulfur content of the fuel oil, and the
SO<INF>2</INF> emissions in pounds per hour so that EPA can establish
an SO<INF>2</INF> emissions limit for fuel oil.
On April 6, 2018, Minorca submitted a request to modify the
SO<INF>2</INF> limit established in the 2016 FIP. Minorca ranked hourly
data from the period March 1, 2017, through March 31, 2018, adjusted
the calculated limit based on potential increased production rates, and
requested an emission limit of 73.79 lbs SO<INF>2</INF>/hour. On
October 14, 2019, Minorca submitted additional hourly SO<INF>2</INF>
CEMS emission data for the time period of September 8, 2018, through
September 7, 2019, revising their request to an emission limit of
208.66 lbs SO<INF>2</INF>/hr. Minorca adjusted the calculated limit
based on potential increased production rates, maximum ore sulfur
content based on a ratio of maximum percent sulfur, and pellet type.
Using the equation set forth at 40 CFR 52.1235(f)(2) and the most
recent CEMS data from September 8, 2018, through September 7, 2019, EPA
calculated an SO<INF>2</INF> emission limit of 68.2 lbs SO<INF>2</INF>/
hour.\29\ There is no basis in the FIP for adjusting emission limits to
account for possible future production levels or possible higher ore
sulfur content. Therefore, based on these data and as provided at 40
CFR 52.1235(b)(2)(v) and 40 CFR 51.308(e), EPA is proposing that an
emission limit of 68.2 lbs SO<INF>2</INF>/hr, based on a 30-day rolling
average, reflects SO<INF>2</INF> BART for the Minorca indurating
furnace.
---------------------------------------------------------------------------
\29\ See Minorca Emission Limit Calculations, available in the
docket for this action.
---------------------------------------------------------------------------
D. Northshore
For Northshore, the Original FIP set an aggregate emission limit of
39.0 lbs SO<INF>2</INF>/hour for Furnace 11 (EU100/EU104) and Furnace
12 (EU110/EU114), based on a 30-day rolling average and excluding
emissions resulting from the combustion of fuel oil, with a requirement
that the owner or operator calculate a revised limit based on one year
of hourly CEMS data and submit such data and calculations to EPA by 20
months after March 8, 2013.
On April 11, 2018, Northshore submitted an SO<INF>2</INF> emission
limit modification request which included CEMS data from January 16,
2017, through January 15, 2018. Northshore adjusted the calculated
emission limit based on potential increased production rates and
requested a limit of 22.1 lbs SO<INF>2</INF>/hour.
On November 21, 2018, Northshore submitted a revised limit
modification request of 49 lbs SO<INF>2</INF>/hr. This limit
modification request included data for the time period of January 16,
2017, through January 15, 2018, and adjusted the calculated limit based
on potential increased production rates and potential increases in ore
sulfur content. On November 10, 2022, Northshore submitted hourly
SO<INF>2</INF> CEMS data for the period of January 16, 2017, through
January 15, 2018, as requested by EPA, to allow for EPA's independent
calculation of emission limits.
Using the equation set forth at 52.1235(f)(2) and the hourly
SO<INF>2</INF> CEMS data from January 16, 2017 through January 15,
2018, EPA calculated an aggregate SO<INF>2</INF> emission limit of 17.0
lbs SO<INF>2</INF>/hour for Furnaces 11 and 12.\30\ There is no basis
in the FIP for adjusting emission limits to account for possible future
production levels or possible higher ore sulfur content. Therefore,
based on these data and as provided at 40 CFR 52.1235(b)(2)(vi), EPA is
proposing that an aggregate SO<INF>2</INF> emission limit of 17.0 lbs
SO<INF>2</INF>/hr for Northshore Furnaces 11 and 12, based on a 30-day
rolling average, reflects SO<INF>2</INF> BART for Northshore.
---------------------------------------------------------------------------
\30\ See Northshore Emission Limit Calculations, available in
the docket for this action.
---------------------------------------------------------------------------
IV. CAA Section 110(l)
Under CAA section 110(l) (sometimes referred to as an ``anti-
backsliding'' provision), EPA cannot approve a plan revision ``if the
revision would interfere with any applicable requirement concerning
attainment and reasonable further progress (as defined in section 7501
of this title), or any other applicable requirement of this chapter.''
Based on the following analysis, we find that our revisions to the 2016
FIP are consistent with CAA section 110(l) because they will not
interfere with any applicable requirement concerning attainment or
reasonable further progress or any other applicable requirements of the
CAA.
A. NOX Emission Limits
When the 2016 FIP was promulgated, NO<INF>X</INF> control
technology had not yet been installed on the furnaces at Tilden,
Hibbing, Minorca, and UTAC. Therefore, EPA established initial emission
limitations based on the modeled (estimated) performance of the
proposed technology along with a procedure to refine and modify the
emission limits within a specified range based upon CEMS data collected
after installation of the NO<INF>X</INF> control technology. The 2016
FIP also allowed for the establishment of a single NO<INF>X</INF> limit
for all fuels. However, the NO<INF>X</INF> emission limits in the 2016
FIP are not enforceable and final until EPA takes action to confirm or
modify the initial emission limits established in the 2016 FIP. Because
the NO<INF>X</INF> limits established in the 2016 FIP have not been
confirmed and made enforceable through the procedures set forth in the
2016 FIP, and are not currently enforceable, the proposed
NO<INF>X</INF> emission limits do not alter any existing enforceable
limits, since there are no current enforceable limits. Therefore,
approval of the proposed NO<INF>X</INF> limits would not interfere with
any applicable requirement concerning attainment or reasonable further
progress, or any other applicable requirement of the CAA.
Additionally, even if EPA were to evaluate the proposed
NO<INF>X</INF> emission limits in relation to the relevant provisions
of the 2016 FIP, we believe the FIP will not interfere with any
applicable requirement concerning attainment or reasonable further
progress, or any other applicable requirements of the CAA.\31\ EPA's
proposed action will complete the process set forth in the 2016 FIP to
finalize enforceable NO<INF>X</INF> emission limits for Tilden,
Hibbing, UTAC, and Minorca within ranges previously established. The
NO<INF>X</INF> emission limits EPA is proposing reflect BART because
they were calculated using the corrected UPL equation and actual
emission data recorded by CEMS, after installation of the required low-
NO<INF>X</INF> technology, pursuant to the procedures set forth in
[[Page 96161]]
the 2016 FIP. While crossline averaging was not addressed in the 2016
FIP, under the BART Guidelines, a source may be permitted to ``
`average' emissions across any set of BART-eligible emission units
within a fenceline, as long as the emission reductions from each
pollutant being controlled for BART would be equal to those reductions
that would be obtained by simply controlling each of the BART-eligible
units that constitute BART-eligible sources.'' \32\ Based on EPA's
analysis, the crossline average emission limits proposed for Hibbing
and UTAC are equal to the reductions that would be obtained by
controlling each line separately.
---------------------------------------------------------------------------
\31\ 40 CFR 52.1183(k)(1)(viii), 52.1235(b)(1)(iv)(A)(8) and
52.1235(b)(1)(iv)(B)(8).
\32\ 40 CFR part 51, appendix Y, at V.
---------------------------------------------------------------------------
The proposed NO<INF>X</INF> emission limits do not reflect a change
in EPA's BART determination. Rather, the proposed limits were
calculated using CEMS data and the corrected UPL equation, following
the procedure set forth in the 2016 FIP, to more accurately reflect an
emission limit consistent with the actual emission reduction
capabilities of the BART controls and within the natural gas ranges
established in the 2016 FIP. Therefore, there are no expected increases
in NO<INF>X</INF> emissions compared to the ranges set in the 2016 FIP.
B. SO2 Emission Limits
EPA is proposing to revise the SO<INF>2</INF> emission limits
applicable to Minorca, Northshore, and Tilden. Minorca and Northshore
are straight-grate furnaces that do not co-fire with coal;
SO<INF>2</INF> emissions from these sources result from sulfur in the
ore processed in the furnaces. As discussed previously, when the
Original FIP was promulgated, SO<INF>2</INF> BART for Minorca and
Northshore was established as no further controls. EPA set initial
SO<INF>2</INF> emission limits based on limited stack test data and
established a procedure to refine those limits when CEMS data became
available. EPA is proposing to modify the Minorca emission limit from
38.16 lbs SO<INF>2</INF>/hour to 68.2 lbs SO<INF>2</INF>/hour and the
Northshore emission limit from 39.0 lbs SO<INF>2</INF>/hour to 17.0 lbs
SO<INF>2</INF>/hour. These proposed revised emission limits do not
reflect a change in EPA's BART determination or in operations at the
facilities that would lead to an increase or decrease in SO<INF>2</INF>
emissions. Rather, the emission limits EPA is proposing establish
emission limits that more accurately reflect BART because they were
calculated using the corrected UPL equation and actual emission data
recorded by CEMS, pursuant to the procedures set forth in the Original
FIP.
Similarly, the 2016 FIP established SO<INF>2</INF> BART for Tilden
as a limit on the sulfur content of the coal and no further controls,
and set an SO<INF>2</INF> emission limit for Tilden along with a
process to modify that limit when CEMS data became available. EPA is
not proposing to revise any limits on the sulfur content of coal at
Tilden. EPA is only proposing to modify Tilden's emissions limit from
500 lbs SO<INF>2</INF>/hour to 189 lbs SO<INF>2</INF>/hour. The revised
emission limit was calculated using the corrected UPL equation and
actual emission data recorded by CEMS, pursuant to the procedures set
forth in the 2016 FIP.
In sum, as a result of the revised SO<INF>2</INF> emissions limits
described above, EPA does not expect changes in SO<INF>2</INF>
emissions from these sources. The limits do not reflect a change in
EPA's BART determination or in operations at the facilities. Rather,
the proposed limits more accurately reflect actual emissions that were
calculated using newly available CEMS data and the corrected UPL
equation.
C. Regional Haze SIPs
On June 12, 2012 (77 FR 34801), EPA approved Minnesota's regional
haze plan for the first implementation planning period as satisfying
the applicable requirements in 40 CFR 51.308, except for BART emission
limits for the taconite facilities. Among the regional haze plan
elements approved were Minnesota's long-term strategy for making
reasonable progress toward visibility goals. Minnesota's long-term
strategy did not rely on the achievement of any particular degree of
emission control from the taconite plants to achieve reasonable
progress goals.
On December 3, 2012 (77 FR 71533), EPA approved Michigan's regional
haze plan for the first implementation planning period as satisfying
the applicable requirements in 40 CFR 51.308, except for BART emission
limits for Tilden, St. Mary's Cement, and Escanaba Paper Company. Among
the regional haze plan elements approved was Michigan's long-term
strategy for making reasonable progress toward visibility goals.
Michigan's long-term strategy did not rely on the achievement of any
particular degree of emission control from the taconite plants to
achieve reasonable progress goals.
On August 23, 2021, Michigan submitted a revision to their regional
haze SIP for the second implementation planning period. Michigan's
submittal provided a long-term strategy and reasonable progress goals
that included 2028 emission projections for Tilden based on a 2016
modeling platform developed by LADCO that did not rely on emission
limits or ranges in the 2016 FIP.
On December 20, 2022, Minnesota submitted a revision to its
regional haze SIP for the second implementation period. Minnesota's
long-term strategy included implementation of the current applicable
limits and ranges in the Original FIP and 2016 FIP for Hibbing,
Minorca, UTAC, and Northshore. However, in applying the long-term
strategy to develop its reasonable progress goals, Minnesota used 2028
projected emissions modeling that relied on the 2016 FIP limits only
for UTAC and not for Hibbing, Minorca, or Northshore. For Hibbing and
Minorca, Minnesota's modeling utilized 2028 projected emissions
provided by LADCO using the 2016 emissions modeling platform since CEMS
data was not available at the time. For Northshore, Minnesota accounted
for the facility being idled until 2031, which was incorporated into an
enforceable agreement as an Administrative Order by Consent issued by
the Minnesota Pollution Control Agency to Northshore and Cleveland-
Cliffs, Inc. To project 2028 emissions for UTAC, Minnesota used 2017
CEMS data to convert NO<INF>X</INF> and SO<INF>2</INF> emissions and
associated heat input into emission rates that allowed for a comparison
to the limits and ranges in the 2016 FIP. Minnesota kept heat input
rates the same and assumed compliance at the least stringent end of the
emission limit ranges (e.g., for an emission limit range of 2.8-3.0 lbs
NO<INF>X</INF>/MMBtu, Minnesota assumed 3.0 lbs NO<INF>X</INF>/MMBtu in
the emission calculations), resulting in conservative emission
projections for 2028. Using a photochemical model based on the 2028
emission projections for all selected sources in their regional haze
plan, including the taconite facilities, Minnesota estimated future
visibility and established their reasonable progress goals.
Although EPA has not yet taken final action on the regional haze
SIP revisions submitted by Michigan and Minnesota for the second
implementation period, the assumptions used in the long-term strategies
and reasonable progress goals were no more stringent than the currently
applicable Original FIP and 2016 FIP emission limits and ranges or the
revised limits we are proposing in this action. Therefore, the revised
NO<INF>X</INF> emission limits for Tilden, Hibbing, UTAC, Minorca, and
Northshore represent greater control overall than was assumed in
Michigan's and Minnesota's long-term strategy and would not result in a
degradation of the reasonable progress goals required by 40 CFR
51.308(d)(1).
[[Page 96162]]
D. National Ambient Air Quality Standards (NAAQS) and Reasonable
Further Progress
With respect to requirements concerning attainment of the NAAQS and
reasonable further progress, EPA is proposing to finalize
NO<INF>X</INF> BART emission limits for seven subject-to-BART units at
four facilities within the ranges established in the 2016 FIP. EPA is
also proposing to finalize SO<INF>2</INF> emission limits for three
facilities which will not result in an increase in SO<INF>2</INF>
emissions. Thus, the proposed FIP revision will not interfere with
attainment and reasonable further progress requirements.
E. Conclusion
We find that these revisions are consistent with CAA section
110(l). The previous sections of the notice explain how the proposed
FIP revision will comply with applicable regional haze requirements and
general implementation plan requirements and demonstrate that it will
not interfere with any regional haze program requirements, attainment
and reasonable further progress, or any other requirement of the CAA.
V. Environmental Justice Considerations
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 (EJ) 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 communities with EJ concerns.
EPA believes that the human health and environmental conditions
that exist prior to this action do not result in disproportionate and
adverse effects on communities with EJ concerns. To identify
environmental burdens and susceptible populations in communities nearby
the Tilden, Hibbing, Minorca, Northshore, and UTAC facilities, and to
examine the implications of the proposed NO<INF>X</INF> and
SO<INF>2</INF> emission limits, EPA utilized the EJScreen tool to
evaluate environmental and demographic indicators within a 3-mile
buffer, a 10-mile buffer, and the county that each facility is located
in (Marquette County, Michigan for Tilden; St. Louis County, Minnesota
for Hibbing, Minorca, and UTAC; and Lake County, Minnesota for
Northshore).
EPA's screening-level analysis indicates that communities near the
facilities affected by this action score below the national average for
the EJScreen ``Demographic Index'', which is the average of an area's
percent minority and percent low-income populations, i.e., the two
demographic indicators explicitly named in Executive Order 12898.
Additionally, the results indicate that these areas score below the
80th percentile (in comparison to the nation as a whole) in the 13 EJ
Indexes established by EPA, which include a combination of
environmental and demographic information. EPA has provided that if any
of the EJ indexes for the areas under consideration are at or above the
80th percentile nationally, then further review may be appropriate. As
discussed in the EPA's EJ technical guidance, communities with EJ
concerns often experience greater exposure and disease burdens than the
general population, which can increase their susceptibility to adverse
health effects from environmental stressors.
EPA believes that this action is not likely to result in new
disproportionate and adverse effects on communities with EJ concerns.
This action proposes to set final NO<INF>X</INF> and SO<INF>2</INF>
emission limits which are not expected to result in new or increased
burdens on residents, including those in communities of EJ concern, as
specified in Executive Order 12898.
EPA invited the identification of EJ and other concerns during its
Tribal consultations which occurred prior to proposing emission limits
for all five taconite facilities. No EJ concerns were raised in the
context of this action. We have determined that this rulemaking will
not have disproportionately high and adverse human health or
environmental effects on communities with EJ concerns. The information
supporting this Executive Order review is contained in the docket for
this action, including the EJSCREEN reports considering a 3-mile
buffer, a 10-mile buffer, and the county that each taconite facility is
in.
VI. Proposed Action
EPA is proposing to modify the UPL equations used to establish
NO<INF>X</INF> and SO<INF>2</INF> emission limits and to finalize
NO<INF>X</INF> and/or SO<INF>2</INF> limits for the indurating furnaces
at five taconite facilities in accordance with the procedure set forth
in the 2016 FIP. Specifically, EPA is proposing to approve the
following NO<INF>X</INF> limits, with compliance to be determined on a
rolling 30-day average: 3.0 lbs NO<INF>X</INF>/MMBtu for all fuels for
Tilden Line 1; a crossline average limit of 1.5 lb NO<INF>X</INF>/MMBtu
for Hibbing Lines 1, 2, and 3; a crossline average emission limit of
3.0 lbs NO<INF>X</INF>/MMBtu for all fuels for UTAC Lines 1 and 2; and
1.6 lbs NO<INF>X</INF>/MMBtu for Minorca's indurating furnace. EPA is
proposing to approve the following SO<INF>2</INF> limits, with
compliance to be determined on a rolling 30-day average: 189 lbs
SO<INF>2</INF>/hr for all fuels for Tilden Line 1; an aggregate
emission limit of 247.8 lbs SO<INF>2</INF>/hr for Hibbing Lines 1, 2,
and 3; 68.2 lbs SO<INF>2</INF>/hr for Minorca's indurating furnace; and
an aggregate limit of 17.0 lbs SO<INF>2</INF>/hr for Northshore
Furnaces 11 and 12.
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 14094: Modernizing Regulatory Review
This action is not a significant regulatory action as defined in
Executive Order 12866, as amended by Executive Order 14094, and was
therefore not subject to a requirement for Executive Order 12866
review.
B. Paperwork Reduction Act
This proposed action does not impose an information collection
burden under the provisions of the Paperwork Reduction Act, 44 U.S.C.
3501 et seq. Because the FIP applies to just the taconite facilities in
Michigan and Minnesota, the Paperwork Reduction Act does not apply. See
5 CFR 1320.3(c).
C. Regulatory Flexibility Act
I certify that this proposed action will not have a significant
economic impact on a substantial number of small entities under the
RFA. This proposed action will not impose any requirements on small
entities. This action, if finalized, will add additional controls to
certain sources. None of these sources are owned by small entities, and
therefore are not small entities.
D. Unfunded Mandates Reform Act (UMRA)
This proposed action does not contain any unfunded mandate as
described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or
uniquely affect small governments. The proposed action imposes no
enforceable duty on any state, local or Tribal governments or the
private sector.
E. Executive Order 13132: Federalism
This proposed 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.
[[Page 96163]]
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This proposed action does not have Tribal implications, as
specified in Executive Order 13175. It will not have substantial direct
effects on Tribal governments. Thus, Executive Order 13175 does not
apply to this action. Consistent with the EPA Policy on Consultation
and Coordination with Indian Tribes, EPA did discuss this action in
conference calls with the Michigan and Minnesota Tribes.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
This action is not subject to Executive Order 13045 because it is
not 3(f)(1) significant as defined in Executive Order 12866, and
because EPA does not believe the environmental health or safety risks
addressed by this action present a disproportionate risk to children.
To the extent this action, if finalized, will limit emissions of
NO<INF>X</INF> and SO<INF>2</INF> emissions, the rule will have a
beneficial effect on children's health by reducing air pollution.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This action is not subject to Executive Order 13211 (66 FR 28355,
May 22, 2001), because it is not a significant regulatory action under
Executive Order 12866.
I. National Technology Transfer and Advancement Act
This rulemaking does not involve technical standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations and
Executive Order 14096: Revitalizing Our Nation's Commitment to
Environmental Justice for All
EPA believes that the human health and environmental conditions
that exist prior to this action do not result in disproportionate and
adverse effects on communities with Environmental Justice concerns.
This proposed FIP limits emissions of NO<INF>X</INF> and SO<INF>2</INF>
from five taconite facilities in Michigan and Minnesota. EPA believes
that this action is not likely to result in new disproportionate and
adverse effects on communities with environmental justice concerns.
EPA performed an EJ analysis, as is described above in the section
titled, ``Environmental Justice Considerations.'' The analysis was done
for the purpose of providing additional context and information about
this rulemaking to the public, not as a basis of the action. Due to the
nature of the action being taken here, this action is expected to have
a neutral to positive impact on the air quality of the affected area.
In addition, there is no information in the record upon which this
decision is based inconsistent with the stated goal of E.O. 12898 of
achieving EJ for communities with EJ concerns.
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Regional
haze, Reporting and recordkeeping requirements, Sulfur oxides.
Michael S. Regan,
Administrator.
For the reasons stated in the preamble, EPA proposes to amend title
40 CFR part 52 as follows:
PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
0
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
0
2. Section 52.1183 is amended by:
0
a. in paragraph (k) revising (1), (3), (4) and (5);
0
b. in paragraph (l) revising (3), (4)(v) and (4)(xii);
0
c. in paragraph (n) revising (1) and (2); and
0
d. removing and reserving paragraph (p).
The revisions read as follows:
Sec. 52.1183 Visibility protection.
* * * * *
(k) Tilden Mining Company, or any subsequent owner/operator of the
Tilden Mining Company facility in Ishpeming, Michigan, shall meet the
following requirements:
(1) NOX Emission Limits.
(i) An emission limit of 3.0 lbs NO<INF>X</INF>/MMBTU, based on a
30-day rolling average, shall apply to Tilden Grate Kiln Line 1
(EUKILN1) beginning January 3, 2025.
(ii) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
(2) SO2 Emission Limits. * * *
(3) The owner or operator of the Tilden Grate Kiln Line 1 (EUKILN1)
furnace shall meet an emission limit of 189.0 lbs SO<INF>2</INF>/hr,
based on a 30-day rolling average, beginning on January 3, 2025.
Compliance with this emission limit shall be demonstrated with data
collected by a continuous emissions monitoring system (CEMS) for
SO<INF>2</INF>. Beginning November 12, 2016, any coal burned on Tilden
Grate Kiln Line 1 shall have no more than 0.60 percent sulfur by weight
based on a monthly block average. The sampling and calculation
methodology for determining the sulfur content of coal must be
described in the monitoring plan required for this furnace.
(4) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in (k)(5)
must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#84d6b1c5d6c0d6e1f4ebf6f0edeae3c4e1f4e5aae3ebf2"><span class="__cf_email__" data-cfemail="6331562231273106130c11170a0d04230613024d040c15">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
(5) Records shall be kept for any day during which fuel oil is
burned as fuel (either alone or blended with other fuels) in Grate Kiln
Line 1. These records must include, at a minimum, the gallons of fuel
oil burned per hour, the sulfur content of the fuel oil, and the
SO<INF>2</INF> emissions in pounds per hour. If any fuel oil is burned
after the first day that SO<INF>2</INF> CEMS are required to be
operational, then the records must be submitted, for each calendar
year, to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#87d5b2c6d5c3d5e2f7e8f5f3eee9e0c7e2f7e6a9e0e8f1"><span class="__cf_email__" data-cfemail="085a3d495a4c5a6d78677a7c61666f486d7869266f677e">[email protected]</span></a> no later
than 30 days after the end of each calendar year.
(l) Testing and monitoring.
* * *
(3) The owner or operator shall install, certify, calibrate,
maintain, and operate one or more continuous diluent monitor(s)
(O<INF>2</INF> or CO<INF>2</INF>) and continuous stack gas flow rate
monitor(s) on Tilden Grate Kiln Line 1 to allow conversion of the
NO<INF>X</INF> and SO<INF>2</INF> concentrations to units of the
standard (lbs/MMBTU and lbs/hr, respectively) unless a demonstration is
made that a diluent monitor and/or continuous flow rate monitor are not
needed for the owner or operator to demonstrate compliance with
applicable emission limits in units of the standard.
(4) * * *
* * * * *
(v) The owner or operator of each CEMS must furnish the Regional
Administrator a written report of the results of each quarterly
performance evaluation and a data accuracy assessment pursuant to 40
CFR part 60 appendix F within 60 days after the calendar quarter in
which the
[[Page 96164]]
performance evaluation was completed. These reports shall be submitted
to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#d082e591b9a295beb6bfa2b3b5bdb5bea490b5a0b1feb7bfa6"><span class="__cf_email__" data-cfemail="0e5c3b4f677c4b6068617c6d6b636b607a4e6b7e6f20696178">[email protected]</span></a>.
* * * * *
(xii) Data substitution must not be used for purposes of
determining compliance under this regulation. If CEMS data is measuring
only a portion of the NO<INF>X</INF> or SO<INF>2</INF> emitted during
startup, shutdown, or malfunction conditions, the CEMS data may be
supplemented, but not modified, by the addition of calculated emission
rates using procedures set forth in the site specific monitoring plan.
* * * * *
(n) Reporting requirements.
(1) Unless instructed otherwise, all requests, reports, submittals,
notifications, and other communications required by this section shall
be submitted to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#8cdeb9cde5fec9e2eae3feefe9e1e9e2f8cce9fceda2ebe3fa"><span class="__cf_email__" data-cfemail="653750240c17200b030a17060008000b11250015044b020a13">[email protected]</span></a>.
References in this section to the Regional Administrator shall mean the
EPA Regional Administrator for Region 5.
(2) The owner or operator of each BART affected unit identified in
this section and CEMS required by this section must provide to the
Regional Administrator the written notifications, reports, and plans
identified at paragraphs (n)(2)(i) through (viii) of this section.
* * *
* * * * *
(p) [Reserved]
* * * * *
0
3. Section 52.1235 is amended by:
0
a. in paragraph (b) revising (1)(ii), (1)(iv), (1)(v), (1)(vi),
(2)(ii), (2)(v) and (2)(vi);
0
b. in paragraph (c) revising (1), (2), (3), (4)(ii), (4)(v), and
(4)(xii); and
0
c. in paragraph (e) revising (1) and (2); and
0
d. revising paragraph (f).
The revisions read as follows:
Sec. 52.1235 Regional haze.
* * * * *
(b) * * *
(1) NO<INF>X</INF> emission limits.
(i) * * *
(ii) Hibbing Taconite Company
(A) An aggregate emission limit of 1.5 lbs NO<INF>X</INF>/MMBtu,
based on a 30-day rolling average, shall apply to the combined
NO<INF>X</INF> emissions from the three indurating furnaces, Line 1
(EU020), Line 2 (EU021), and Line 3 (EU022), beginning on January 3,
2025. To determine the aggregate emission rate, the combined
NO<INF>X</INF> emissions from Lines 1, 2, and 3 shall be divided by the
total heat input to the three lines (in MMBtu) during every rolling 30-
day period.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
(iii) * * *
(iv) United Taconite
(A) An aggregate emission limit of 3.0 lbs NO<INF>X</INF>/MMBtu,
based on a 30-day rolling average, shall apply to the combined
NO<INF>X</INF> emissions from the two indurating furnaces, Grate Kiln
Line 1 (EU040) and Grate Kiln Line 2 (EU042), beginning on January 3,
2025. To determine the aggregate emission rate, the combined
NO<INF>X</INF> emissions from Grate Kiln Line 1 and Grate Kiln Line 2
shall be divided by the total heat input to the two lines (in MMBtu)
during every rolling 30-day period.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
(v) Minorca Mine
(A) An emission limit of 1.6 lbs NO<INF>X</INF>/MMBtu, based on a
30-day rolling average, shall apply to the Minorca Mine indurating
furnace (EU026). This emission limit will become enforceable on January
3, 2025.
(B) Compliance with this emission limit will be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
(vi) Northshore Mining Company--Silver Bay: An emission limit of
1.5 lbs NO<INF>X</INF>/MMBtu, based on a 30-day rolling average, shall
apply to Furnace 11 (EU100/EU104) beginning October 10, 2018. An
emission limit of 1.5 lbs NO<INF>X</INF>/MMBtu, based on a 30-day
rolling average, shall apply to Furnace 12 (EU110/114) beginning
October 11, 2019. However, for any 30, or more, consecutive days when
only natural gas is used at either Northshore Mining Furnace 11 or
Furnace 12, a limit of 1.2 lbs NO<INF>X</INF>/MMBtu, based on a 30-day
rolling average, shall apply. An emission limit of 0.085 lbs
NO<INF>X</INF>/MMBtu, based on a 30-day rolling average, shall apply to
Process Boiler #1 (EU003) and Process Boiler #2 (EU004) beginning
October 10, 2021. The 0.085 lbs NO<INF>X</INF>/MMBtu emission limit for
each process boiler applies at all times a unit is operating, including
periods of start-up, shut-down and malfunction.
(2) SO2 Emission Limits.
(i) * * *
(ii) Hibbing Taconite Company
(A) An aggregate emission limit of 247.8 lbs SO<INF>2</INF>/hour,
based on a 30-day rolling average, shall apply to the combined
SO<INF>2</INF> emissions from the three indurating furnaces, Line 1
(EU020), Line 2 (EU0021), and Line 3 (EU022), beginning on February 10,
2017. To determine the aggregate emission rate, the combined
SO<INF>2</INF> emissions from Lines 1, 2, and 3 shall be divided by the
total hours of operation of the three lines during every rolling 30-day
period.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
SO<INF>2</INF>.
(C) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in
(b)(2)(vii) must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#a0f295e1f2e4f2c5d0cfd2d4c9cec7e0c5d0c18ec7cfd6"><span class="__cf_email__" data-cfemail="5e0c6b1f0c1a0c3b2e312c2a3730391e3b2e3f70393128">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
(iii) * * *
(iv) * * *
(v) Minorca Mine
(A) An emission limit of 68.2 lbs SO<INF>2</INF>/hr, based on a 30-
day rolling average, shall apply to the indurating furnace (EU026)
beginning January 3, 2025.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
SO<INF>2</INF>.
(C) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in
(b)(2)(vii) must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#df8dea9e8d9b8dbaafb0adabb6b1b89fbaafbef1b8b0a9"><span class="__cf_email__" data-cfemail="085a3d495a4c5a6d78677a7c61666f486d7869266f677e">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
(vi) Northshore Mining Company--Silver Bay
(A) An aggregate emission limit of 17.0 lbs SO<INF>2</INF>/hr,
based on a 30-day rolling average, shall apply to Furnace 11 (EU100/
EU104) and Furnace 12 (EU110/EU114) beginning January 3, 2025. To
determine the aggregate emission rate, the combined SO<INF>2</INF>
emissions from Furnace 11 and Furnace 12 shall be divided by the total
hours of operation of the two furnaces during every rolling 30-day
period.
(B) Compliance with these emission limits shall be demonstrated
with data collected by a continuous emissions monitoring system (CEMS)
for SO<INF>2</INF>.
(C) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in
(b)(2)(vii) must
[[Page 96165]]
be submitted, for each calendar year, to the Regional Administrator at
<a href="/cdn-cgi/l/email-protection#bcee89fdeef8eed9ccd3cec8d5d2dbfcd9ccdd92dbd3ca"><span class="__cf_email__" data-cfemail="1240275340564077627d60667b7c75527762733c757d64">[email protected]</span></a> no later than 30 days after the end of each
calendar year so that a limit can be set.
(D) The owner or operator may submit to EPA for approval an
alternative monitoring procedure request. The request shall include at
least one year of CEMS data demonstrating consistent values at or below
5 lbs SO<INF>2</INF>/hr. The alternative monitoring procedure request
shall not remove the obligation to maintain and operate a flow rate
monitor in the stack. If approved, the owner or operator would not be
required to operate the SO<INF>2</INF> CEMS and may demonstrate
continuous compliance using an emission factor derived from the average
of at least one year of existing SO<INF>2</INF> data using the
procedure set forth in the site specific monitoring plan, and verified
by annual stack tests using EPA approved test methods, multiplied by
the daily measured flow rate as recorded by the flow rate monitor and
recorded as the daily lb/hr SO<INF>2</INF> emission rate.
(vii) * * *
(c) Testing and monitoring.
(1) The owner or operator of the respective facility shall install,
certify, calibrate, maintain and operate continuous emissions
monitoring systems (CEMS) for NO<INF>X</INF> on United States Steel
Corporation, Keetac unit EU030; Hibbing Taconite Company units EU020,
EU021, and EU022; United States Steel Corporation, Minntac units EU225,
EU261, EU282, EU315, and EU334; United Taconite units EU040 and EU042;
Minorca Mine unit EU026; and Northshore Mining Company-Silver Bay units
Furnace 11 (EU100/EU104) and Furnace 12 (EU110/EU114). Compliance with
the emission limits for NO<INF>X</INF> shall be determined using data
from the CEMS.
(2) The owner or operator shall install, certify, calibrate,
maintain, and operate CEMS for SO<INF>2</INF> on United States Steel
Corporation, Keetac unit EU030; Hibbing Taconite Company units EU020,
EU021, and EU022; United States Steel Corporation, Minntac units EU225,
EU261, EU282, EU315, and EU334; United Taconite units EU040 and EU042;
Minorca Mine unit EU026; and Northshore Mining Company-Silver Bay units
Furnace 11 (EU100/EU104) and Furnace 12 (EU110/EU114).
(3) The owner or operator shall install, certify, calibrate,
maintain, and operate one or more continuous diluent monitor(s)
(O<INF>2</INF> or CO<INF>2</INF>) and continuous stack gas flow rate
monitor(s) on the BART affected units to allow conversion of the
NO<INF>X</INF> and SO<INF>2</INF> concentrations to units of the
standard (lbs/MMBTU and lbs/hr, respectively) unless a demonstration is
made that a diluent monitor and/or continuous flow rate monitor are not
needed for the owner or operator to demonstrate compliance with
applicable emission limits in units of the standards.
(4) * * *
(i) * * *
(ii) CEMS must be installed and operational such that the
operational status of the CEMS identified in paragraphs (c)(1) and (2)
of this section shall be verified by, as a minimum, completion of the
manufacturer's written requirements or recommendations for
installation, operation, and calibration of the devices.
* * * * *
(v) The owner or operator of each CEMS must furnish the Regional
Administrator a written report of the results of each quarterly
performance evaluation and a data accuracy assessment pursuant to 40
CFR part 60 appendix F within 60 days after the calendar quarter in
which the performance evaluation was completed. These reports shall be
submitted to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#0e5c3b4f677c4b6068617c6d6b636b607a4e6b7e6f20696178"><span class="__cf_email__" data-cfemail="7a284f3b13083f141c1508191f171f140e3a1f0a1b541d150c">[email protected]</span></a>.
* * * * *
(xii) Data substitution must not be used for purposes of
determining compliance under this section. If CEMS data is measuring
only a portion of the NO<INF>X</INF> or SO<INF>2</INF> emitted during
startup, shutdown, or malfunction conditions, the CEMS data may be
supplemented, but not modified, by the addition of calculated emission
rates using procedures set forth in the site specific monitoring plan.
* * *
* * * * *
(e) Reporting Requirements
(1) Unless instructed otherwise, all requests, reports, submittals,
notifications, and other communications required by this section shall
be submitted to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#d587e094bca790bbb3baa7b6b0b8b0bba195b0a5b4fbb2baa3"><span class="__cf_email__" data-cfemail="cd9ff88ca4bf88a3aba2bfaea8a0a8a3b98da8bdace3aaa2bb">[email protected]</span></a>.
References in this section to the Regional Administrator shall mean the
EPA Regional Administrator for Region 5.
(2) The owner or operator of each BART affected unit identified in
this section and CEMS required by this section must provide to the
Regional Administrator the written notifications, reports and plans
identified at paragraphs (e)(2)(i) through (viii) of this section.
* * *
* * * * *
(f) Equations for establishing the upper predictive limit--
(1) Equation for normal distribution and statistically independent
data.
[GRAPHIC] [TIFF OMITTED] TP04DE24.035
Where:
x = average or mean of hourly test run data;
t<INF>[(</INF>n<INF>-1),(0.99)]</INF> = t score, the one-tailed t
value of the Student's t distribution for a specific degree of
freedom (n-1) and a confidence level (0.99, to reflect the 99th
percentile)
s\2\ = variance of the hourly data set;
n = number of values (e.g., 5,760 if 8 months of valid lbs
NO<INF>X</INF>/MMBTU hourly values)
m = number of values used to calculate the test average (m = 720 as
per averaging time)
(i) To determine if statistically independent, use the Rank von
Neumann Test on p. 137 of data Quality Assessment: Statistical Methods
for Practitioners EPA QA/G-9S.
(ii) Alternative to Rank von Neumann test to determine if data are
dependent, data are dependent if t test value is greater than t
critical value, where:
[GRAPHIC] [TIFF OMITTED] TP04DE24.036
r = correlation between data points
t critical = t<INF>[(n-2),(0.95)]</INF> = t score, the two-tailed t
value of the Student's t distribution for a specific degree of
freedom (n-2) and a confidence level (0.95)
(iii) The Anderson-Darling normality test is used to establish
whether the data are normally distributed. That is, a distribution is
considered to be normally distributed when p > 0.05.
(2) Non-parametric equation for data not normally distributed and
normally distributed but not statistically independent.
m = (n+1) * [alpha]
m = the rank of the ordered data point, when data are sorted
smallest to largest. The data points are 720-hour averages for
establishing NO<INF>X</INF> limits.
n = number of data points (e.g., 5040 720-hourly averages for eight
months of valid NO<INF>X</INF> lbs/MMBTU values)
[alpha] = 0.99, to reflect the 99th percentile
If m is a whole number, then the limit, UPL, shall be computed as:
UPL = Xm
Where:
Xm = value of the mth data point in terms of lbs SO<INF>2</INF>/hr
or lbs NO<INF>X</INF>/MMBtu, when the data are sorted smallest to
largest.
If m is not a whole number, the limit shall be computed by linear
interpolation according to the following equation.
[[Page 96166]]
UPL = xm = xmi[middot]md= xmi + 0.md(xm(i+1) - xmi)
Where:
mi = the integer portion of m, i.e., m truncated at zero decimal
places, and
md = the decimal portion of m
[FR Doc. 2024-27635 Filed 12-3-24; 8:45 am]
BILLING CODE 6560-50-P
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on December 4, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.