2024-21896. Air Plan Approval; Michigan; Attainment Plan for the Detroit 2010 Sulfur Dioxide Nonattainment Area

Table 1—Emission Limits Included in Michigan's Detroit SO ₂ Nonattainment Area Plan

Unit	SO 2 emission limit (lb/hr)	Permit No. and date	SIP status
U.S. Steel—Zug Island
Boilerhouse 1 (all stacks combined) A1 Blast Furnace	55.00 0.00	Permit to Install 110-23, effective September 26, 2023	EPA is proposing to incorporate these permits into Michigan's SIP.
B2 Blast Furnace	40.18
D4 Blast Furnace	40.18
A/B Blas Furnace Flares	60.19
D Furnace Flare	60.19
Boilerhouse 2	* 750.00/81.00	Permit to Install 108-23, effective November 14, 2024
U.S. Steel—Ecorse
Hot Strip Mill—Slab Reheat Furnace 1 Hot Strip Mill—Slab Reheat Furnace 2	0.31 0.31	Permit to Install 110-23, effective September 26, 2023	EPA is proposing to incorporate this permit into Michigan's SIP.
Hot Strip Mill—Slab Reheat Furnace 3	0.31
Hot Strip Mill—Slab Reheat Furnace 4	0.31
Hot Strip Mill—Slab Reheat Furnace 5	0.31
No. 2 Baghouse	3.30
Main Plant Boiler No. 8	0.07
Main Plant Boiler No. 9	0.07
EES Coke
Combustion Stack	544.6	Permit to Install 51-08C, effective November 21, 2014	EPA is proposing to incorporate this permit into Michigan's SIP.
( print page 80443)
DTE Trenton Channel  **
Trenton Channel Unit 9	5,907	Permit to Install 125-11C, effective January 1, 2017	Incorporated into Michigan's SIP as part of March 19, 2021, action (86 FR 14827). However, the source has since shut down, and any restart would require a revision to the source's Title V permit, subject to EPA review and possible objection if a permit revision would not ensure compliance with all applicable CAA requirements.
Carmeuse Lime
Carmeuse Lime Stack	470	Permit to Install 193-14A, effective October 1, 2018	Incorporated into Michigan's SIP as part of March 19, 2021, action (86 FR 14827).
Cleveland-Cliffs Steel Corporation  **
Furnace B Baghouse Stack Furnace B Stove Stack	71.9 38.75	Permit MI-ROP-A8640-2016a, modified January 19, 2017	EPA is proposing to incorporate this permit into Michigan's SIP.
Furnace B Baghouse and Stove Stacks (combined)	77.8
Furnace C Baghouse Stack	179.65
Furnace C Stove Stack	193.6
Furnace C Baghouse and Stove Stacks (combined)	271.4
DIG  **
Boilers 1, 2, and 3 (combined)	420	Permit 253-02A, effective September 25, 2003	EPA is proposing to incorporate the sections of this permit containing the 420 lb/hr limit and associated requirements (cover page, section 5.1d, and sections 5.2-5.10) into Michigan's SIP.
Boilers 1, 2, and 3 and Flares 1 and 2 (combined)	840	Permit to Install 109-23, effective September 26, 2023	EPA is proposing to incorporate this permit into Michigan's SIP.
* U.S. Steel—Zug Island Boilerhouse 2 shall emit less than 750.00 lbs/hr unless Boilerhouse 1, A1 Blast Furnace, B2 Blast Furnace, D4 Blast Furnace, A/B Blast Furnace Flares, or D Furnace Flare is operating, in which case it shall emit less than 81.00 lbs/hr. In addition to the limit, this permit requires a new 170-foot stack to be constructed for Boilerhouse 2 by November 14, 2024.
** The limit for Trenton Channel is expressed as a 30-day average limit, and the limits for Cleveland-Cliffs Steel Corporation and DIG are expressed as daily average limits. EPA's FIP proposal addresses the use of these longer-term average limits, both with respect to the general suitability of using such limits for demonstrating attainment and with respect to whether the particular limits included in the plan have been suitably demonstrated to provide for attainment.