16408 Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[EPA–HQ–OAR–2017–0664; FRL–5925.1– 

01–OAR] 

RIN 2060–AV58 

National Emission Standards for 

Hazardous Air Pollutants: Taconite 

Iron Ore Processing 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The U.S. Environmental 

Protection Agency (EPA) is finalizing 

amendments to the National Emission 

Standards for Hazardous Air Pollutants 

(NESHAP) for Taconite Iron Ore 

Processing. Specifically, the EPA is 

finalizing maximum achievable control 

technology (MACT) standards for 

mercury (Hg) and establishing revised 

emission standards for hydrogen 

chloride (HCl) and hydrogen fluoride 

(HF). This final action ensures that 

emissions of all hazardous air pollutants 

(HAP) emitted from the Taconite Iron 

Ore Processing source category are 

regulated. 

DATES: This final rule is effective March 

6, 2024. The incorporation by reference 

(IBR) of certain publications listed in 

the rule is approved by the Director of 

the Federal Register (FR) as of March 6, 

2024. The incorporation by reference of 

certain other material listed in the rule 

was approved by the Director of the 

Federal Register as of October 26, 2020. 

ADDRESSES: The EPA established a 

docket for this action under Docket ID 

No. EPA–HQ–OAR–2017–0664. All 

documents in the docket are listed on 

the https://www.regulations.gov/ 

website. Although listed, some 

information is not publicly available, 

e.g., Confidential Business Information 

(CBI) or other information whose 

disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the internet and is publicly available 

only in hard copy. With the exception 

of such material, publicly available 

docket materials are available 

electronically in https://

www.regulations.gov/or in hard copy at 

the EPA Docket Center, Room 3334, 

WJC West Building, 1301 Constitution 

Avenue NW, Washington, DC. The 

Public Reading Room is open from 8:30 

a.m. to 4:30 p.m., Monday through 

Friday, excluding legal holidays. The 

telephone number for the Public 

Reading Room is (202) 566–1744, and 

the telephone number for the EPA 

Docket Center is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: For 

questions about this final action, contact 

David Putney, Sector Policies and 

Programs Division (D243–02), Office of 

Air Quality Planning and Standards, 

U.S. Environmental Protection Agency, 

109 T.W. Alexander Drive, P.O. Box 

12055, Research Triangle Park, North 

Carolina, 27711; telephone number: 

(919) 541–2016; email address: 

putney.david@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Preamble acronyms and 

abbreviations. Throughout this 

document the use of ‘‘we,’’ ‘‘us,’’ or 

‘‘our’’ is intended to refer to the EPA. 

We use multiple acronyms and terms in 

this preamble. While this list may not be 

exhaustive, to ease the reading of this 

preamble and for reference purposes, 

the EPA defines the following terms and 

acronyms here: 

ACI activated carbon injection 

BTF beyond-the-floor 

CAA Clean Air Act 

CBI Confidential Business Information 

CEMS continuous emission monitoring 

system 

CFR Code of Federal Regulations 

D.C. Circuit United States Court of Appeals 

for the District of Columbia Circuit 

DSI dry sorbent injection 

EJ environmental justice 

EPA Environmental Protection Agency 

ESP electrostatic precipitator 

FR Federal Register 

HAP hazardous air pollutant(s) 

HCl hydrochloric acid 

HF hydrogen fluoride 

Hg mercury 

ICR information collection request 

km kilometer 

LEAN Louisiana Environmental Action 

Network 

lb/LT pounds of HAP (i.e., Hg, HCl, or HF) 

emitted per long ton of pellets produced 

MACT maximum achievable control 

technology 

MWh/yr megawatt-hours per year 

MPCA Minnesota Pollution Control Agency 

NAICS North American Industry 

Classification System 

NESHAP National Emission Standards for 

Hazardous Air Pollutants 

ng/g nanograms per gram 

NTTAA National Technology Transfer and 

Advancement Act 

OAQPS Office of Air Quality Planning and 

Standards 

OMB Office of Management and Budget 

PM particulate matter 

PRA Paperwork Reduction Act 

RFA Regulatory Flexibility Act 

RTR residual risk and technology review 

tpy tons per year 

UPL upper prediction limit 

mg/Nm3 microgram per normal cubic meter 

UMRA Unfunded Mandates Reform Act 

VCS voluntary consensus standards 

Organization of this document. The 

information in this preamble is 

organized as follows: 

I. General Information 

A. Does this action apply to me? 

B. Where can I get a copy of this document 

and other related information? 

C. Judicial Review and Administrative 

Reconsideration 

II. Background 

A. What is the statutory authority for this 

action? 

B. What is the source category and how 

does the current NESHAP regulate its 

HAP emissions? 

C. What changes did we propose for the 

Taconite Iron Ore Processing source 

category? 

III. What is the rationale for our final 

decisions and amendments for the 

Taconite Iron Ore Processing source 

category? 

A. MACT Standards for Mercury 

B. Revised Emission Standards for HCl and 

HF 

C. What other amendments are we 

finalizing? 

D. What are the effective and compliance 

dates for the mercury, HCl, and HF 

emission standards? 

IV. Summary of Cost, Environmental, and 

Economical Impacts 

A. What are the affected sources? 

B. What are the air quality impacts? 

C. What are the cost impacts? 

D. What are the economic impacts? 

E. What analysis of environmental justice 

did we conduct? 

V. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

B. Paperwork Reduction Act (PRA) 

C. Regulatory Flexibility Act (RFA) 

D. Unfunded Mandates Reform Act 

(UMRA) 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. National Technology Transfer and 

Advancement Act (NTTAA) and 1 CFR 

Part 51 

H. 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 

I. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

J. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

K. Congressional Review Act (CRA) 

I. General Information 

A. Does this action apply to me? 

Table 1 of this preamble lists the 

NESHAP and associated regulated 

industrial source category that is the 


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Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16409 

1 Louisiana Environmental Action Network v. 

EPA, 955 F.3d 1088 (D.C. Cir. 2020) (‘‘LEAN’’). 

subject of this final rule. Table 1 is not 

intended to be exhaustive, but rather 

provides a guide for readers regarding 

the entities that this final action is likely 

to affect. The final standards are directly 

applicable to the affected sources. 

Federal, state, local, and Tribal 

government entities are not affected by 

this final action. As defined in the 

Initial List of Categories of Sources 

Under Section 112(c)(1) of the Clean Air 

Act Amendments of 1990 (see 57 FR 

31576; July 16, 1992) and 

Documentation for Developing the 

Initial Source Category List, Final 

Report (see EPA–450/3–91–030; July 

1992), the Taconite Iron Ore Processing 

source category includes any facility 

engaged in separating and concentrating 

iron ore from taconite, a low-grade iron 

ore to produce taconite pellets. The 

source category includes, but is not 

limited to, the following processes: 

liberation of the iron ore by wet or dry 

crushing and grinding in gyratory 

crushers, cone crushers, rod mills, and 

ball mills; pelletizing by wet tumbling 

with a balling drum or balling disc; 

induration using a straight grate or grate 

kiln indurating furnace; and finished 

pellet handling. 

TABLE 1—NESHAP AND SOURCE CATEGORIES AFFECTED BY THIS FINAL ACTION

Source category NESHAP NAICS code 1

Taconite Iron Ore Processing .................................................... 40 CFR part 63, subpart RRRRR .............................................. 21221 

1 North American Industry Classification System. 

B. Where can I get a copy of this 

document and other related 

information? 

In addition to being available in the 

docket, an electronic copy of this action 

is available on the internet. Following 

signature by the EPA Administrator, the 

EPA will post a copy of this final action 

at https://www.epa.gov/stationarysources-air-pollution/taconite-iron-oreprocessing-national-emissionstandards-hazardous. Following 

publication in the Federal Register, the 

EPA will post the Federal Register 

version of the final rule and key 

technical documents at this same 

website. 

C. Judicial Review and Administrative 

Reconsideration 

Under Clean Air Act (CAA) section 

307(b)(1), judicial review of this final 

action is available only by filing a 

petition for review in the United States 

Court of Appeals for the District of 

Columbia Circuit (D.C. Circuit) by May 

6, 2024. Under CAA section 307(b)(2), 

the requirements established by this 

final rule may not be challenged 

separately in any civil or criminal 

proceedings brought by the EPA to 

enforce the requirements. 

Section 307(d)(7)(B) of the CAA 

further provides that only an objection 

to a rule or procedure which was raised 

with reasonable specificity during the 

period for public comment (including 

any public hearing) may be raised 

during judicial review. This section also 

provides a mechanism for the EPA to 

reconsider the rule if the person raising 

an objection can demonstrate to the 

Administrator that it was impracticable 

to raise such objection within the period 

for public comment or if the grounds for 

such objection arose after the period for 

public comment (but within the time 

specified for judicial review) and if such 

objection is of central relevance to the 

outcome of the rule. Any person seeking 

to make such a demonstration should 

submit a Petition for Reconsideration to 

the Office of the Administrator, U.S. 

EPA, Room 3000, WJC South Building, 

1200 Pennsylvania Ave. NW, 

Washington, DC 20460, with a copy to 

both the person(s) listed in the 

preceding FOR FURTHER INFORMATION

CONTACT section, and the Associate 

General Counsel for the Air and 

Radiation Law Office, Office of General 

Counsel (Mail Code 2344A), U.S. EPA, 

1200 Pennsylvania Ave. NW, 

Washington, DC 20460. 

II. Background 

A. What is the statutory authority for 

this action? 

In the Louisiana Environmental 

Action Network v. EPA (‘‘LEAN’’) 

decision issued on April 21, 2020, the 

D.C. Circuit held that the EPA has an 

obligation to address regulatory gaps, 

such as missing standards for HAP 

known to be emitted from a major 

source category, when the Agency 

conducts the 8-year technology review 

required by CAA section 112(d)(6).1

Emissions data collected from the 

exhaust stacks of existing taconite 

indurating furnaces indicate that Hg is 

emitted from the source category. 

However, Hg emissions from the 

Taconite Iron Ore Processing source 

category are not regulated under the 

existing Taconite Iron Ore Processing 

NESHAP. To meet the EPA’s obligations 

under CAA section 112(d)(6), in this 

action, the EPA is establishing new 

standards for Hg emissions from the 

Taconite Iron Ore Processing source 

category that reflect MACT for Hg 

emitted from taconite indurating 

furnaces, pursuant to CAA sections 

112(d)(2) and (3). 

The EPA is also finalizing revised 

standards for HCl and HF pursuant to 

CAA section 112(d)(6). CAA section 

112(d)(6) requires the EPA to review 

standards promulgated under CAA 

section 112 and revise them ‘‘as 

necessary (taking into account 

developments in practices, processes, 

and control technologies)’’ no less often 

than every 8 years. 

B. What is the source category and how 

does the current NESHAP regulate its 

HAP emissions? 

The Taconite Iron Ore Processing 

NESHAP (codified at 40 Code of Federal 

Regulations (CFR) part 63, subpart 

RRRRR) applies to each new or existing 

ore crushing and handling operation, 

ore dryer, pellet indurating furnace, and 

finished pellet handling operation at a 

taconite iron ore processing plant that is 

(or is part of) a major source of HAP 

emissions. Taconite iron ore processing 

plants separate and concentrate iron ore 

from taconite, a low-grade iron ore 

containing 20- to 25-percent iron, and 

produce taconite pellets, which are 60- 

to 65-percent iron. The current NESHAP 

includes particulate matter (PM) limits 

that, prior to this final action, served as 

a surrogate for particulate metal HAP, 

HCl, and HF emissions. The existing PM 

emissions limits were summarized in 

table 2 of the proposal (see 88 FR 30917; 

May 15, 2023). The current NESHAP 

does not presently include standards for 

Hg emissions. 

There are currently eight taconite iron 

ore processing plants in the United 

States: six plants are located in 

Minnesota and two are located in 

Michigan. This includes the Empire 

Mining facility in Michigan, which 

maintains an air quality permit to 

operate, but has been indefinitely idled 

since 2016 and is therefore not included 


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16410 Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 

in any analyses (e.g., estimates of 

emissions or cost impacts) associated 

with this final rulemaking. 

C. What changes did we propose for the 

Taconite Iron Ore Processing source 

category? 

On May 15, 2023, the EPA published 

a proposal in the Federal Register to set 

MACT standards for Hg emissions from 

indurating furnaces in the source 

category and to revise the existing 

emission standards for HCl and HF for 

indurating furnaces. The PM emission 

limits in the current NESHAP will 

continue to serve as surrogate for 

particulate metal HAP (e.g., nickel and 

arsenic). The EPA proposed that 

compliance with the emission standards 

for Hg, HCl, and HF be demonstrated 

through operating limits, monitoring, 

and performance testing. We also 

proposed minor changes to the 

electronic reporting requirements found 

in 40 CFR 63.9641(c) and 40 CFR 

63.9641(f)(3) to reflect new procedures 

for reporting CBI that included an email 

address for owners and operators to 

electronically submit compliance 

reports containing CBI to the Office of 

Air Quality Planning and Standards 

(OAQPS) CBI Office. Finally, we 

requested comment on our evaluation 

that the addition of 1-bromopropane (1– 

BP) to the CAA section 112 HAP list 

would not impact the Taconite Iron Ore 

Processing NESHAP because, based on 

our knowledge of the source category 

and available emissions data, 1–BP is 

not emitted from this source category. 

III. What is the rationale for our final 

decisions and amendments for the 

Taconite Iron Ore Processing source 

category? 

For each issue, this section provides 

a description of what we proposed and 

what we are finalizing, a summary of 

key comments and responses, and the 

EPA’s rationale for the final decisions 

and amendments. For all comments not 

discussed in this preamble, comment 

summaries and the EPA’s responses can 

be found in the document, Summary of 

Public Comments and Responses for 

Proposed Amendments to the National 

Emission Standards for Hazardous Air 

Pollutants for Taconite Iron Ore 

Processing, which is available in the 

docket for this action. 

A. MACT Standards for Mercury 

1. What did we propose for the Taconite 

Iron Ore Processing source category? 

As described in the May 15, 2023, 

proposal (88 FR 30917), we proposed 

MACT standards for Hg for new and 

existing indurating furnaces that 

reflected the MACT floor level of 

control, based on the 99-percent upper 

prediction limit (UPL), of 1.4 × 10¥5

pounds of Hg emitted per long ton of 

taconite pellets produced (lb/LT) for 

existing sources and 3.1 × 10¥6 lb/LT 

for new sources. We also proposed an 

emissions averaging compliance 

alternative that would allow taconite 

iron ore processing facilities with more 

than one existing indurating furnace to 

comply with a Hg emissions limit of 

1.26 × 10¥5 lb/LT by averaging 

emissions on a production-weighted 

basis for two or more existing indurating 

furnaces located at the same facility. In 

the proposal, we explained that the 

emissions averaging compliance 

alternative reflected a 10 percent 

adjustment factor to the proposed 

MACT floor standard and that we 

expected this 10 percent adjustment 

factor would result in Hg reductions 

greater than those achieved by 

compliance with the MACT floor on a 

unit-by-unit basis. We proposed that 

compliance with the Hg MACT 

standards would be demonstrated 

through initial and periodic 

performance testing (completed at least 

twice per 5-year permit term), 

establishing operating limits for each 

control device used to comply with the 

Hg standards, and installing and 

operating continuous parameter 

monitoring systems (CPMS) to ensure 

continuous compliance with the Hg 

standards. 

For the proposal, in addition to 

calculating the MACT floor, pursuant to 

CAA section 112(d)(2), we also assessed 

more stringent ‘‘beyond-the-floor’’ (BTF) 

regulatory options for the Hg MACT 

standards. As discussed in the proposal 

(88 FR 30923), unlike the MACT floor’s 

minimum stringency requirements, the 

EPA must examine various impacts of 

the more stringent BTF regulatory 

options in determining whether MACT 

standards are to reflect BTF 

requirements. These impacts include 

the cost of achieving additional 

emissions reductions beyond those 

achieved by the MACT floor level of 

control, any non-air quality health and 

environmental impacts that would 

result from imposing controls BTF, and 

energy requirements of such BTF 

measures. If the EPA concludes that the 

more stringent regulatory options have 

unreasonable impacts, the EPA selects 

the MACT floor level of control as 

MACT. However, if the EPA concludes 

that impacts associated with BTF levels 

of control are reasonable in light of 

additional HAP emissions reductions 

achieved, then the EPA selects those 

BTF levels as MACT. 

We considered BTF regulatory 

options that were 10, 20, 30, and 40 

percent more stringent than the MACT 

floor and calculated the capital and 

annual costs as well as secondary 

impacts associated with each option. 

For a detailed discussion of our analysis 

of emissions reductions and potential 

secondary impacts developed for the 

proposal, please see the memorandum, 

Development of Impacts for the 

Proposed Amendments to the NESHAP 

for Taconite Iron Ore Processing, which 

is available in the docket for this action. 

We proposed that requiring new or 

existing furnaces to meet BTF emission 

limits was not reasonable based on the 

estimated capital and operating costs 

and cost-effectiveness. 

2. What comments did we receive on 

the proposed Hg MACT standards, and 

what are our responses? 

Comment: Industry commenters 

provided data that they indicated 

corrected the Hg stack test data 

submitted in response to the CAA 

section 114 Information Collection 

Request (ICR) sent to the taconite 

facilities in 2022 for the Tilden, UTAC, 

Keetac, and Hibbing facilities that were 

used when calculating the baseline 

emissions, the MACT floor standards, 

and the emission reductions. The 

commenters indicated that the error in 

the Keetac emissions data resulted in an 

overestimate of both the baseline 

emissions and the estimated emission 

reductions that could be achieved if the 

proposed Hg standards were adopted. 

Response: In response to these 

comments and revised data provided, 

the EPA reviewed the Hg emissions data 

that we used in the proposal to calculate 

baseline Hg emissions. At proposal we 

estimated total baseline Hg emissions 

were 1,010 pounds per year. The EPA 

confirmed that errors were present in 

the Hg emissions data used to calculate 

the baseline emissions. We revised the 

emissions data as appropriate based on 

the emissions data provided by industry 

commenters and recalculated the 

baseline emissions, MACT floor 

emission limits, emission reductions, 

and estimated capital and annual costs 

accordingly for the final rule. The 

updates to the emissions data did not 

impact the MACT floor limit for existing 

sources but did decrease the baseline 

emissions and the expected Hg 

emissions reductions for existing 

sources. The updates to the emissions 

data changed the Hg standard for new 

sources from 3.1 × 10¥6 lb/LT to 2.6 × 

10¥6 lb/LT. The updated baseline Hg 

emissions for the final rule are 

estimated to be 751 pounds per year 

(0.38 tons per year (tpy)). We estimate 


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that unit-by-unit compliance with the 

final MACT floor limit will result in a 

reduction of 232 pounds of Hg 

emissions per year and a reduction of 

247 pounds per year of Hg emissions if 

all facilities with more than one existing 

taconite furnace elect to demonstrate 

compliance through the emissions 

averaging compliance alternative. Our 

analysis is presented in detail in the 

memorandum, Development of Impacts 

for the Final Amendments to the 

NESHAP for Taconite Iron Ore 

Processing. The updated emissions data 

used in the revised calculations for the 

final rule are summarized in a separate 

memorandum, Final Emissions Data 

Collected in 2022 for Indurating 

Furnaces Located at Taconite Iron Ore 

Processing Plants. These documents are 

available in the docket for this action. 

Comment: One commenter 

recommended the proposed limit for the 

emissions averaging compliance 

alternative for existing sources should 

have the same number of significant 

figures as the MACT floor limit. Instead 

of 1.26 × 10¥5 lb/LT, the limit for the 

emissions averaging compliance 

alternative for existing sources would be 

rounded up to 1.3 × 10¥5 lb/LT. 

Response: The EPA agrees with the 

commenter that the Hg emission limit 

for the emissions averaging compliance 

option should have only two significant 

figures. The limit cannot have more 

significant figures than Hg MACT floor 

from which it was derived, which has 

only two significant figures. As 

recommended by commenters, the Hg 

emission limit in the final rule is 

revised to 1.3 × 10¥5 lb/LT so that the 

limit for the emissions averaging 

compliance alternative has the same 

number of significant figures as the 

other Hg limits finalized in this 

rulemaking. 

We estimate that the final Hg 

emissions averaging compliance 

alternative will reduce Hg emissions by 

247 pounds per year, if Hibbing and 

Minntac elect to demonstrate 

compliance through the emissions 

averaging compliance alternative by 

each facility installing mercury controls 

on two furnaces and averaging the 

emissions across all furnaces located at 

their facility. We expect that, should 

Hibbing and Minntac elect to 

demonstrate compliance through the 

emissions averaging compliance 

alternative, the Hg reductions would 

still be greater than the reductions we 

anticipate would be achieved through 

unit-by-unit compliance with the MACT 

floor level of control. For additional 

details, please refer to section IV.A.1 of 

the proposal preamble (88 FR 30925). 

More information on the final Hg 

standards, including the detailed cost 

estimates for the Hg emissions averaging 

compliance alternative, may be found in 

the memorandum, Development of 

Impacts for the Final Amendments to 

the NESHAP for Taconite Iron Ore 

Processing, which is available in the 

docket for this action. 

Comment: Commenters recommended 

that the proposed 40 CFR 63.9621(d)(4) 

and 63.9631(j) be revised to allow the 

mass of taconite pellets produced to be 

determined indirectly through 

calculation based on industry standards. 

They noted that pellet mass is measured 

prior to offsite shipment and later 

‘‘trued-up’’ at the end of each month. 

Response: The EPA agrees that 

taconite pellet production can be 

determined indirectly through 

calculation using bulk density and 

volume measurements. We have revised 

the language in 40 CFR 63.9621(d)(4) 

and 63.9631(j) to allow the weight of 

taconite pellets produced to be 

determined either by direct 

measurement using weigh hoppers, belt 

weigh feeders, or weighed quantities in 

shipments, or calculated using the bulk 

density and volume measurements. 

Comment: Industry commenters 

stated that the capital and operating 

costs for Hg controls were 

underestimated in the proposal and that 

the estimated capital costs were 

significantly below cost estimates 

developed by industry. The commenters 

thought the retrofit factor of 1.2 used by 

the EPA failed to adequately account for 

the additional costs incurred when 

retrofitting an existing emission unit 

with new controls. They recommended 

the EPA use the capital costs prepared 

by industry and apply a retrofit factor of 

1.5 or 1.6 with a contingency factor of 

30 percent to account for the higher 

costs for retrofit projects. The 

commenters also stated that the total 

annual costs were underestimated 

because the EPA had underestimated 

costs for activated carbon, electricity, 

and waste disposal and used an interest 

rate that was too low. Industry 

commenters also stated that currently, 

some plants recycle iron particles 

collected by their particulate emission 

control device, but that the presence of 

activated carbon would create product 

quality issues and make recycling no 

longer possible. The commenters stated 

the EPA had not accounted for the loss 

of product and increased waste disposal 

costs in the cost estimates prepared for 

the proposal. The commenters provided 

cost estimates for the Keetac, Minorca, 

Minntac and UTAC facilities that 

included estimates of the amount of 

product they assert would be lost if 

scrubber solids are not recycled back 

through the process and the estimated 

price for the lost product. The 

commenters also disagreed with the 

estimated labor costs, arguing that both 

the number of operator hours and 

hourly labor rates were too low. 

Response: For the final rule, the EPA 

has updated the capital and annual 

costs to reflect the costs in 2023 dollars 

using an interest rate of 8.5 percent and 

updated unit prices for activated carbon, 

utilities, and labor. The EPA also 

assessed the commenters concerns that 

ACI would prevent plants from 

recovering iron particles collected with 

other solids by their particulate 

emission control device. Based on the 

information provided by industry, ten 

indurating furnaces currently collect the 

solids from their particulate control 

devices and recycle the solids back to 

the production process, thereby 

recovering valuable iron product. 

Commenters said plants using ACI 

would not be able to continue to recover 

iron in this way because carbon would 

impact the quality of their product. 

Commenters said EPA should account 

for costs due to the loss of product and 

increased cost of waste disposal of the 

unrecoverable product. Industry 

provided estimates of the amount of 

iron that would be lost for the furnaces 

located at the UTAC, Minorca, and 

Minntac plants. We used this data to 

estimate iron losses for the Hibbing 

plant and multiplied the estimated iron 

losses for each furnace by the current 

market price of iron to estimate the costs 

associated with the loss iron product. 

The updated cost estimates that we are 

using for the final rule, including the 

basis for the 8.5 percent interest rate, are 

documented in the memorandum, 

Development of Impacts for the Final 

Amendments to the NESHAP for 

Taconite Iron Ore Processing, which is 

available in the docket for this action. 

The EPA reviewed the capital cost 

information submitted by industry 

during the comment period and found 

the information submitted consisted of 

a total capital cost for equipment. 

However, no breakdown was provided 

from which we could ascertain what 

was included in the cost and little 

information was provided on how the 

costs were derived. The lack of detail in 

the cost estimates combined with little 

supporting documentation made it 

impossible for the EPA to assess the 

accuracy of the cost estimates submitted 

by industry. Industry commenters 

indicated that the estimated equipment 

costs for the air pollution control 

equipment for the Minorca and UTAC 

facilities they submitted were estimated 

using cost data from another project at 

a different facility and scaled using the 


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2EPA’s Control Cost Manual provides guidance 

for the development of capital and annual costs for 

air pollution control devices. The Control Cost 

Manual focuses on point source and stationary area 

source air pollution controls. A copy of the manual 

is available at https://www.epa.gov/economic-andcost-analysis-air-pollution-regulations/cost-reportsand-guidance-air-pollution. 

3Sargent & Lundy, LLC, IPM Model—Updates to 

Cost and Performance for APC Technologies 

Mercury Control Cost Development Methodology, 

January 2017. A copy of this document is available 

at https://www.epa.gov/sites/default/files/2018-05/ 

documents/attachment_5-6_hg_control_cost_

development_methodology.pdf. 

‘rule of six-tenths.’ The ‘rule of sixtenths’ is a method by which equipment 

costs are estimated as the cost of a 

known project multiplied by a capacity 

factor raised to the power of six-tenths. 

The ‘rule of six-tenths’ can provide a 

reasonable order of magnitude estimate 

of equipment costs where the capacities 

of the two systems are reasonably 

similar. However, the commenters did 

not identify the facility or provide a 

detailed description of the project to 

which they are applying the rule of sixtenths. Commenters also failed to 

provide a detailed breakdown of the 

equipment costs used in the ‘rule of sixtenths’ estimate. Without additional 

information, the EPA was unable to 

assess the accuracy of the equipment 

costs provided by commenters. 

Therefore, we are not making any 

changes based on this information. 

We disagree with the commenters’ 

recommendations that a retrofit factor of 

1.5 or 1.6 should be applied to the 

capital costs with a 30-percent 

contingency factor. Retrofit factors 

account for costs directly related to the 

demolition, fabrication, and installation 

of the control system. For the venturi 

scrubbers we included the 3-percent 

contingency factor and applied a retrofit 

factor of 1.2 to the estimate of the total 

capital investment for new construction. 

The EPA’s Air Pollution Control Cost 

Manual indicates a 3-percent 

contingency factor is considered 

appropriate for a mature air pollution 

control technology and states that 

retrofit costs are ‘‘generally minimal’’ 

for venturi scrubbers because of their 

small footprint.2 While we agree with 

the commenters that retrofits may, in 

some cases, be more expensive than 

new construction, the 1.2 retrofit factor 

used in the cost estimates provides a 

reasonable increase to account for the 

higher cost associated with retrofit 

projects that involve replacing an 

existing venturi scrubber with a highefficiency venturi scrubber, where 

infrastructure (e.g., water and power 

supply) already exist. The retrofit factor 

applied does not have a significant 

impact on the total annual costs. If a 

retrofit factor of 1.6 is applied, as 

recommended by the commenters, the 

total annual costs would increase by 

about 2 percent (less than $2 million for 

replacing the venturi scrubbers on all 11 

furnaces with mercury emissions 

currently exceeding the MACT floor. We 

did not apply a retrofit factor to the 

capital costs for the activated carbon 

injection (ACI) system because the costs 

were estimated using a methodology 

developed by Sargent & Lundy for the 

EPA’s Integrated Planning Model 

(IPM).3 The IPM methodology is based 

on costs for retrofitting ACI on utility 

boilers and therefore already represents 

the average or typical costs for ACI 

retrofits. 

A contingency factor is reserved for 

costs that could incur a reasonable but 

unanticipated increase but are not 

directly related to the demolition, 

fabrication, and installation of the 

system. Retrofit and contingency factors 

can be difficult to assess as they vary 

based on site-specific characteristics. 

Nevertheless, the EPA considers the 

methodology used to calculate capital 

and total annual costs to be a reasonable 

approach to estimating costs for the 

purposes of this rulemaking. We note 

that the EPA may not consider costs in 

determining the MACT floor, and that 

the cost estimates for the BTF control 

options identified for Hg emissions were 

determined to be greater than the level 

historically found to be cost-effective for 

controlling Hg emissions. 

Comment: Industry commenters noted 

that the Hg concentrations in taconite 

ore deposits vary widely both within 

each mine and between mines, which in 

turn affects Hg emissions. The 

commenters said the primary source of 

Hg emissions from indurating furnaces 

is from the Hg contained in the 

greenballs (i.e., unfired taconite iron ore 

pellets). The commenters provided Hg 

concentration data for greenballs from 

each taconite iron ore processing facility 

and recommended that the EPA revise 

the proposed Hg limits for new and 

existing furnaces to address the 

variability inherent in the Hg 

concentration of greenballs. They 

suggested the EPA use the data to 

develop a raw material variability factor 

that could be used when calculating the 

MACT floor limits for Hg. The 

commenters noted that the EPA had 

accounted for variability in the Hg 

concentration of raw materials when 

calculating the MACT floor limits for 

other NESHAP. 

Response: The EPA reviewed the Hg 

data submitted by industry and 

determined the data were not adequate 

for us to calculate a variability factor for 

use in deriving the MACT floor limits. 

This decision was based on several 

factors. First, the number of 

measurements submitted for each 

facility varied considerably—from as 

few as three measurements for the best 

performing furnace at Northshore 

(including two measurements on the 

same day) to as many as 948 

measurements for the UTAC plant. The 

very limited data provided for 

Northshore is a concern because 

Northshore’s stack test data showed that 

their furnace was the best performing 

(i.e., had the lowest emissions of Hg). 

The data provided for Northshore are 

insufficient to evaluate temporal 

variability in the Hg content of the 

greenballs at Northshore because the 

data consist of measurements made 

during only two greenball sampling 

episodes: one in January 1997 and the 

other in November 2001. Second, much 

of the data submitted could not be 

validated because the commenters did 

not provide the laboratory reports for 

the test results. For example, the UTAC 

facility provided 948 measurements of 

the Hg concentration of the greenballs at 

their plant but submitted none of the 

laboratory reports needed to corroborate 

their data. Laboratory reports are needed 

to determine whether appropriate 

methods were used for sample 

collection and analysis, to confirm 

appropriate quality assurance and 

quality control measures were taken, 

and to check that the values submitted 

are accurate. In total, we were unable to 

confirm the concentration values for 

over 87 percent of the measurements 

submitted because we lacked the 

laboratory reports. Third, the samples 

were collected at irregularly spaced 

intervals, often with large gaps in time 

during which no samples were 

collected. These sampling intervals 

varied from as little as a few days to 

multiple years. In cases where samples 

were collected over a period of several 

consecutive months, the measurements 

were not collected at consistent 

intervals. Ideally, the samples would be 

collected at representative intervals 

with supporting documentation of the 

sample collection and analysis, to avoid 

bias in the dataset. Finally, the data 

submitted for some facilities included 

measurements that we determined to be 

statistical outliers. For example, we 

identified two statistical outliers in the 

Tilden dataset, where in one case the Hg 

content of greenballs increased from 1.4 

nanograms per gram (ng/g) on July 6, 

2022, to 15.0 ng/g on July 15, 2022, 

before decreasing to 1.2 ng/g on July 22, 

2022. The presence of statistical outliers 

does not necessarily mean the 


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measurements are incorrect. However, 

statistical outliers raise concerns over 

the accuracy and representativeness of 

the measurements, particularly where 

no explanation for the anomaly is 

available. 

Comment: Some commenters 

requested EPA Method 30B be included 

as an acceptable alternative test method 

for measuring Hg emissions from 

indurating furnaces. 

Response: In response to the 

commenters’ request, we reviewed EPA 

Method 30B and determined that this 

method is appropriate for measuring Hg 

emissions from indurating furnaces. In 

the final rule, we have updated the list 

of approved methods for Hg 

measurement to include EPA Method 

30B, in addition to the proposed 

methods. The final rule allows owners 

and operators to use EPA Methods 29 or 

30B in 40 CFR part 60, appendix A–8, 

and the voluntary consensus standard 

(VCS), ASTM D6784–16, Standard Test 

Method for Elemental, Oxidized, 

Particle-Bound and Total Mercury in 

Flue Gas Generated from Coal-Fired 

Stationary Sources (Ontario Hydro 

Method). 

Comment: Industry commenters 

expressed concern that the proposed Hg 

stack testing volumes for performance 

testing to demonstrate compliance with 

the proposed Hg standards were too 

large such that each test run would 

require too much time to complete. 

They recommended that smaller test 

volumes would be appropriate and 

suggested that the test volume be small 

enough to allow each test run to be 

completed within 60 minutes. 

Response: In response to the 

commenters’ concerns regarding the 

stack testing volumes and duration of 

each test run, the EPA reconsidered the 

proposed sample volume requirements 

and revised the performance testing 

requirements in the final rule to require 

a minimum sample volume of 1.7 dry 

standard cubic meters (dscm) (60 dry 

standard cubic feet (dscf)) for EPA 

Method 29 and ASTM D6784–16, 

instead of the 3 dscm sample volume we 

proposed. The 1.7 dscm sample volume 

will allow test runs to be completed in 

approximately 2 hours while still 

ensuring that the required sample 

volume is sufficient for analysis and 

that a non-detect test result indicates 

compliance with the final Hg limits. 

Comment: We received multiple 

comments recommending continuous 

emission monitoring systems (CEMS) 

for Hg be included either as a 

requirement for all indurating furnaces 

or as an optional alternative to 

conducting performance testing and 

establishing operating limits. The 

commenters stated that CEMS would 

ensure continuous compliance with the 

Hg standard and could help lower 

compliance costs by making it possible 

for facilities to vary the ACI rate based 

on the Hg emissions data collected by 

CEMS. Some commenters said facilities 

would be more likely to use CEMS if the 

CEMS provisions were incorporated 

into the rule because facilities would 

not have to apply for approval of an 

alternative monitoring method. 

Response: The EPA agrees with 

recommendations made by commenters 

that suggested CEMS be included as an 

optional alternative to the proposed 

compliance monitoring and 

performance testing requirements. We 

agree that CEMS are an acceptable 

alternative monitoring method for 

assuring compliance with the Hg 

emissions standards. In the final rule, 

we have included provisions that 

provide owners and operators the 

option of using Hg CEMS in lieu of 

establishing operating limits and 

performing periodic performance 

testing. These provisions will provide 

more options for the methods that 

facilities can use to demonstrate 

compliance with the new Hg standards 

and reduce the burden associated with 

applying for Administrator approval of 

an alternative monitoring plan. 

However, we are not requiring 

installation of CEMS due to compliance 

cost considerations, as explained in the 

memorandum, Development of Impacts 

for the Final Amendments to the 

NESHAP for Taconite Iron Ore 

Processing, which is available in the 

docket for this action. 

Comment: Industry commenters were 

concerned that the proposed approach 

to setting operating limits for ACI would 

not allow facilities flexibility to adjust 

the carbon injection rates when 

production decreases. These 

commenters suggested the EPA allow 

flexibility to adjust the average ACI rate 

and average carrier flow rate based on 

taconite pellet production rates during 

stack testing to provide facilities with 

the operational flexibility needed at 

lower production rates. 

Response: We agree with the industry 

commenters that lower ACI and carrier 

gas flow rates would achieve 

compliance with the emission limit 

when production rates are lower than 

the production rates during the 

performance test used to establish 

operating limits. We have included 

provisions in the final rule that allow a 

facility to adjust the operating limits 

based on taconite pellet production. 

Under the requirements of the final rule, 

a facility has the option of establishing 

operating limits for different production 

rates by conducting performance tests at 

the maximum, minimum, and median 

taconite pellet production rates of an 

indurating furnace to develop a 

relationship between the carbon 

injection rate and taconite pellet 

production rate. An owner or operator 

would monitor the taconite pellet 

production rate and adjust the ACI rate 

in accordance with the relationship 

between these parameters developed 

during the performance testing. If the 

taconite pellet production rate falls 

below the minimum rate measured 

during performance testing, the owners 

and operators must maintain a carbon 

injection rate that is equal to, or above, 

the rate determined during the 

performance testing completed at the 

minimum taconite production rate. 

As an alternative, an owner or 

operator may adjust the ACI rate based 

on the direct measurement of Hg 

emitted to the atmosphere. An owner or 

operator must install, calibrate, 

maintain, and operate CEMS to measure 

Hg emissions from each emission stack 

associated with the indurating furnace 

to use this alternative. 

Comment: Industry commenters 

supported the EPA’s decision to set the 

Hg emissions standards at the MACT 

floor rather than setting a BTF standard. 

Industry commenters stated that the 

capital and annual costs required to 

comply with the MACT floor are too 

high and setting BTF standards would 

not be cost-effective. One commenter 

asserted that any standard beyond the 

MACT floor must be justified by a 

‘‘thorough and robust analysis of the 

costs and benefits.’’ The commenter 

agreed with the EPA’s proposed 

determination that the cost-effectiveness 

of the BTF options identified for Hg 

control were above the level historically 

found to be reasonable. 

Several other commenters 

recommended the EPA set a BTF Hg 

standard and recommended the 

standard be at least 30–40 percent more 

stringent than the MACT floor. The 

commenters stated that additional Hg 

reductions can be achieved and that a 

more stringent Hg standard is warranted 

due to the bioaccumulative nature of 

Hg. The commenter noted that many 

water bodies located near taconite 

facilities already have fish consumption 

advisories, which commenters noted 

impact the rights of tribes to exercise 

their traditional life practices. One 

commenter noted that tribes have a 

particular interest in Hg emissions due 

to the Hg-related fish consumption 

advisories that have been issued by 

Minnesota since the 1970s and by the 

Fond du Lac Tribe beginning in 2000. 

One commenter stated that the 30 


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percent BTF option would reduce Hg 

emissions to a level that would help 

address public health concerns 

associated with high concentrations of 

Hg in water, fish tissues, and other 

subsistence resources. Commenters from 

several tribes located near taconite 

facilities stated that the EPA’s Tribal 

trust and treaty responsibilities justified 

adoption of a BTF option. They added 

that the EPA should consider its trust 

responsibility to protect the interests of 

tribes and the tribes’ treaty rights and 

quoted from two EPA policy documents: 

EPA Policy for the Administration of 

Environmental Programs on Indian 

Reservations (issued November 1984) 

and Guidance for Discussing Tribal 

Treaty Rights (issued February 2016). 

Both documents support consideration 

of Tribal rights and protections in 

Agency decision making. Commenters 

noted that the areas impacted by 

taconite iron ore processing plants are 

in the areas covered by a series of 

treaties. These commenters disagreed 

with the EPA’s determination that BTF 

options were not cost-effective. 

Response: The EPA agrees with the 

commenters that said the Hg standard 

should be set at the MACT floor. In our 

analysis, the BTF options were above 

the numbers we have found cost 

effective for Hg controls in prior CAA 

section 112 rulemakings. 

The EPA recognizes the Federal 

government’s trust responsibility, which 

derives from the historical relationship 

between the Federal government and 

Indian Tribes. The EPA acts consistently 

with the Federal government trust 

responsibility by implementing the 

statutes it administers and consulting 

with and considering the interests of 

tribes when taking actions that may 

affect them. As we noted in the 

proposal, the EPA consulted with Tribal 

government officials during the 

development of this rule. The EPA’s 

Office of Air and Radiation held a 

meeting with the Fond du Lac Band of 

Lake Superior Chippewa Reservation 

and the Leech Lake Band of Ojibwe 

Reservation on January 12, 2022, to 

discuss the EPA’s CAA section 114 

information request, and to ensure that 

the views of affected tribes were taken 

into consideration in the rulemaking 

process in accordance with the EPA 

Policy on Consultation and 

Coordination with Indian Tribes. A 

summary of that consultation is 

provided in the document, Consultation 

with the Fond du Lac Band of Lake 

Superior Chippewa and the Leech Lake 

Band of Ojibwe regarding Notice of 

Proposed Rulemaking for the National 

Emission Standards for Hazardous Air 

Pollutants for Taconite Iron Ore 

Processing Amendments on January 12, 

2022, which is available in the docket 

for this action. 

The Agency recognizes the concerns 

raised by numerous Tribal commenters 

regarding impacts to treaty fishing and 

other resource rights. However, for the 

reasons explained below, the EPA is 

declining to set BTF standards for Hg, 

based on the statutory factors that we 

are required to consider pursuant to 

CAA section 112(d)(2) when assessing 

whether to set MACT standards more 

stringent than the MACT floor level of 

control. These statutory factors include 

the cost of achieving such emission 

reduction, and any non-air quality 

health and environmental impacts and 

energy requirements. As discussed in 

paragraphs later in this section, the costeffectiveness values associated with 

BTF standards for this Taconite Iron Ore 

Processing rule are well above the costeffectiveness values that EPA has 

historically accepted when considering 

BTF options for regulating mercury 

emissions. We note that the historic 

acceptable cost-effectiveness values for 

mercury (e.g., up to $22,400 per pound 

[in 2007 dollars] in the 2011 final MATS 

rule, which equates to about $32,000 per 

pound in current dollars) are much 

higher than the cost-effectiveness values 

we have accepted for all other HAPs 

(except for maybe a few exceptions such 

as dioxins and furans) and is based, at 

least in part, on the fact that mercury is 

a persistent, bioaccumulative, toxic 

(PBT) HAP. Nevertheless, we conclude 

that setting BTF Hg standards in this 

rule would be inconsistent with the 

values found to be cost-effective for Hg 

controls in prior rulemakings. We are 

declining to set BTF standards in this 

rule based on cost and other statutory 

factors. 

Section 112(d) of the CAA requires 

the EPA to set emissions standards for 

HAP emitted by sources in each source 

category and subcategory listed under 

CAA section 112(c). The MACT 

standards for existing sources must be at 

least as stringent as the average 

emissions limitation achieved by the 

best performing 12 percent of existing 

sources (for which the Administrator 

has emissions information) or the best 

performing five sources for source 

categories with less than 30 sources 

(CAA sections 112(d)(3)(A) and (B)). 

This level of minimum stringency is 

called the MACT floor. For new sources, 

MACT standards must be at least as 

stringent as the control level achieved in 

practice by the best controlled similar 

source (CAA section 112(d)(3)). The 

EPA may not consider costs or other 

impacts in determining the MACT floor. 

Section 112(d)(2) of the CAA also 

requires the EPA to examine emission 

standards more stringent than the 

MACT floor, which the EPA refers to as 

BTF control options. Unlike standards 

set at the MACT floor level of control, 

when assessing whether to require 

emission standards more stringent than 

the MACT floor, the EPA must consider 

the cost of achieving such emission 

reduction, and any non-air quality 

health and environmental impacts and 

energy requirements. The EPA’s BTF 

analysis evaluated these factors in 

determining whether to establish Hg 

standards more stringent than the 

MACT floor. In developing this final 

rule, we evaluated Hg emission limits 

more stringent than the MACT floor 

after adjusting estimates of Hg 

emissions, Hg emission reductions, and 

control costs as discussed above, 

including those BTF limits suggested by 

commenters, to assess whether a BTF 

option was technically achievable and 

cost-effective. We estimate that the total 

capital costs and total annual costs 

would range from a low of $137 million 

and $92 million, respectively, for a limit 

that is 10 percent more stringent than 

the floor to a high of $148 million and 

$102 million, respectively, for a limit 

that is 40 percent more stringent than 

the floor. The incremental cost 

effectiveness for the BTF options 

examined varied from a low of $46,266 

per pound of Hg reduced for 30 percent 

more stringent than the floor to a high 

of $91,140 per pound of Hg reduced for 

40 percent more stringent than the floor. 

These values are well above the $/ 

pound of Hg reduced that we have 

historically found to be cost-effective 

when considering BTF options for 

regulating Hg emissions. Where EPA has 

taken costs into account, the Agency has 

finalized standards for mercury with 

cost effectiveness estimates of up to 

$32,000/lb Hg reduced (adjusted to 2024 

dollars). See Mercury Cell Chlor-Alkali 

Plants Residual Risk and Technology 

Review (87 FR 27002, May 6, 2022); 

2011 Mercury and Air Toxics (MATS) 

final rule. To date, these are the highest 

cost-effectiveness values that we have 

accepted in the air toxics program for 

any HAP (except for maybe a few 

exceptions such as dioxins and furans), 

largely because of the toxicity and 

nature of Hg. While we conclude that 

mercury standards more stringent than 

the MACT floor are not cost-effective, 

we note that as a result of the revisions 

to the rule being finalized in this 

rulemaking, we will receive compliance 

test information that will allow us to 

evaluate our conclusions and 

potentially inform appropriate future 


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regulatory activities including the next 

statutorily required technology review. 

Mercury is one of the high concern 

HAPs because it is environmentally 

persistent, it bioaccumulates in humans 

and food chains—including in fish, 

which is a concern for subsistence 

needs, uses and cultural practices as 

noted in multiple comments from 

Tribes—and is a neurotoxin that is 

especially of concern for developing 

fetuses and young children. For these 

reasons, mercury is one of the few HAPs 

for which we use the expression of $ per 

pound and consider higher costeffectiveness values. We also estimated 

the secondary impacts of the BTF 

options would range between 155,000 

megawatt-hours per year (MWh/yr) and 

160,000 MWh/yr of electricity (with 

associated secondary air emissions), 

generate between 4.7 million and 7.4 

million gallons of wastewater per year, 

and produce between 110,000 tons and 

112,000 tons of solid waste of per year. 

Based on our assessment of Hg emission 

standards 10 percent, 20 percent, 30 

percent, and 40 percent more stringent 

than the MACT floor, including 

consideration of cost and other statutory 

factors of setting BTF Hg standards for 

indurating furnaces in the source 

category as specified in CAA section 

112(d)(2), in the final rule, we are 

declining to adopt BTF emission 

standards for Hg and are finalizing Hg 

standards at the MACT floor as 

discussed in section III.A.3 of this 

preamble. For more information on our 

analysis of the BTF control options for 

Hg, please see the memorandum, Final 

Maximum Achievable Control 

Technology (MACT) Analysis for 

Mercury Standards for Taconite Iron 

Ore Indurating Furnaces, which is 

available in the docket for this action. 

Comment: Several commenters, 

including the National Park Service, 

several local tribes, and environmental 

organizations said Hg standards for the 

taconite industry were important 

because of the benefits lower Hg 

emissions will have on public health 

and the environment. One commenter 

cited several studies, such as the 

Dragonfly Mercury Project, that 

document elevated levels of Hg and 

higher risks of Hg exposure to humans 

and wildlife in the Great Lakes Region. 

This commenter stated that the upper 

Great Lakes Region is particularly 

sensitive to Hg pollution due to the 

abundance of wetlands and peatlands, 

low-pH lakes, high dissolved organic 

matter, low biological productivity, and 

other factors that provide conditions 

suitable for the conversion of Hg to the 

bioavailable form methylmercury. The 

commenter also stated the impacts of Hg 

on wildlife include reduced foraging 

efficiency, lower reproductive success, 

impaired endocrine modulation, and 

damage to kidney and other tissues. The 

commenters expressed concern over the 

number of fish with Hg levels exceeding 

the human and wildlife health 

thresholds. The commenter cited data 

from a 1998–2016 study that measured 

Hg concentrations in fish from the 

upper Great Lakes at 0.12 ppm wet 

weight, with 24 percent of the fish 

sampled exceeding the EPA human 

health criterion of 0.3 ppm wet weight, 

27 percent of the fish exceeding fisheating wildlife health threshold of 0.2 

ppm whole-body, and 17 percent 

exceeding the fish toxicity benchmark of 

0.3 ppm whole-body. This commenter 

cited studies linking Hg deposition with 

bioaccumulation, including a study of 

Hg concentration in moose teeth from 

Isle Royale National Park, Michigan 

from 1952 to 2002. The commenter 

noted that Hg decreased by about twothirds during the early 1980s but 

remained constant for the following 2 

decades. The commenter cited an 

additional six studies that analyzed the 

concentrations and trends of Hg in bald 

eagle nestlings in the upper Midwest 

from 2006–2015 and long-term trends at 

two Lake Superior sites between 1989– 

2015. These studies show 

concentrations of Hg in nestling breast 

feathers were highest at the Saint Croix 

National Scenic Riverway (6.66 mg/g wet 

weight) and that Hg concentrations have 

increased at two other study area sites. 

The commenters said the new Hg 

standards will help reduce Hg 

deposition in the Great Lakes Region 

and improve public health. The 

commenters asserted that taconite iron 

ore processing plants in Minnesota and 

Michigan have a significant impact on 

the natural resources of the upper Great 

Lakes Region and the elevated Hg levels 

in fish and bird populations. Several 

commenters mentioned the statewide 

fish consumption advisories for Hg in 

Minnesota, Michigan, and Wisconsin 

and noted several water bodies in these 

states are listed as impaired for aquatic 

consumption due to Hg. The 

commenters asserted that the new Hg 

standards will reduce the impact of Hg 

on public health and the environment, 

provide additional protection to 

recreational and subsistence fish 

consumers in national parks and 

surrounding communities, and protect 

natural resources that are of cultural 

significance to many local communities. 

Response: The EPA acknowledges the 

independent research conducted by the 

National Park Service and others on the 

impacts of Hg on the communities and 

wildlife of the upper Great Lakes 

Region. We share the commenters’ 

concern about the elevated Hg levels in 

fish and other wildlife in Minnesota, 

Wisconsin, and Michigan, and the 

critical impact these Hg levels have on 

tribes and low-income populations that 

rely on the fish and wildlife from the 

Great Lakes region. By controlling Hg 

emissions, the Hg MACT standards EPA 

is finalizing in this action for taconite 

iron ore processing plants will achieve 

an estimated reduction of 247 pounds 

per year of mercury emissions from the 

Taconite facilities, which we expect will 

also achieve an unquantified reduction 

of Hg deposition in the Great Lakes 

Region and therefore improve public 

health of local communities, including 

local tribes and low-income 

populations. 

3. What are the final MACT standards 

for Hg and how will compliance be 

demonstrated? 

We are finalizing MACT standards for 

Hg for new and existing indurating 

furnaces that reflect the MACT floor 

level of control, based on the 99-percent 

UPL, of 1.4 × 10¥5 lb/LT for existing 

sources and 2.6 × 10¥6 lb/LT for new 

sources. We are also finalizing the 

emissions averaging compliance 

alternative that allows taconite iron ore 

processing facilities with more than one 

existing indurating furnace to comply 

with a Hg emissions limit of 1.3 × 10¥5

lb/LT by averaging emissions on a 

production-weighted basis for two or 

more existing indurating furnaces 

located at the same facility. 

Owners and operators may 

demonstrate compliance with the new 

Hg standards in one of two ways. Under 

the first option, an owner or operator 

may demonstrate compliance by 

completing performance testing and 

establishing operating limits for each 

control device used to comply with the 

Hg standard. The final rule clarifies that 

performance testing must be performed 

when the production rate is equal to or 

greater than 90 percent of the capacity 

of the indurating furnace. If the 

performance testing cannot be 

performed when the production rate is 

equal to or greater than 90 percent of the 

production rate capacity of the furnace, 

the owner or operator may complete 

testing at a lower production rate if they 

receive approval from the delegated 

authority. An owner or operator 

selecting this option must install and 

operate continuous parameter 

monitoring systems (CPMS) to monitor 

the parameters specified in 40 CFR 

63.9631(g). An owner or operator must 

take corrective action when an 

established operating limit is exceeded. 


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The initial performance testing must be 

completed within 180 calendar days of 

the compliance date specified in 40 CFR 

63.9583(f) for existing sources or within 

180 calendar days of startup for new 

sources, using EPA Methods 29 or 30B 

in 40 CFR part 60, appendix A–8 or the 

VCS ASTM D6784–16, Standard Test 

Method for Elemental, Oxidized, 

Particle-Bound and Total Mercury in 

Flue Gas Generated from Coal-Fired 

Stationary Sources (Ontario Hydro 

Method). The performance tests must be 

repeated at least twice per 5-year permit 

term. 

The second option by which an owner 

or operator may demonstrate 

compliance is through the installation 

and operation of CEMS for Hg. The 

CEMS must be installed, calibrated, 

maintained, and operated in accordance 

with the procedures specified in 40 CFR 

63.9631(j). An owner or operator 

selecting this approach is not required 

to establish operating limits, install and 

operate CPMS, or complete the initial 

and periodic performance testing for Hg 

emissions. 

As discussed in section III.A.2 of this 

preamble, the final rule includes an 

option for adjusting the carbon injection 

rate based on the taconite pellet 

production level. The facility has the 

option of establishing operating limits 

for different production rates by 

conducting performance tests at the 

maximum, minimum and median 

taconite pellet production rates to 

develop a relationship between carbon 

injection rate and taconite pellet 

production rate or by adjusting the ACI 

rate based on Hg emissions data 

collected by CEMS. Facilities that elect 

to adjust the carbon injection rate based 

on taconite production levels will have 

lower compliance costs due to lower 

annual consumption of activated 

carbon. 

Each owner or operator must prepare 

a preventive maintenance plan and keep 

records of calibration and accuracy 

checks of the CPMS or CEMS to 

document proper operation and 

maintenance of all monitoring systems 

used to demonstrate compliance with 

the applicable Hg standard. 

B. Revised Emission Standards for HCl 

and HF 

1. What did we propose for the Taconite 

Iron Ore Processing source category? 

As described in the May 15, 2023, 

proposal (88 FR 30917), we proposed to 

revise the numerical emission limits for 

HCl and HF, pursuant to CAA section 

112(d)(6). CAA section 112(d)(6) 

requires the EPA to review standards 

promulgated under CAA section 112 

and revise them ‘‘as necessary (taking 

into account developments in practices, 

processes, and control technologies)’’ no 

less often than every 8 years; we refer 

to such action under CAA section 

112(d)(6) as a ‘‘technology review.’’ The 

EPA previously completed a technology 

review for the Taconite Iron Ore 

Processing source category in 2020 (85 

FR 45476; July 28, 2020). In the May 15, 

2023, proposal, we proposed to revise 

the HCl and HF standards based on new 

information we obtained in response to 

the 2022 information collection 

concerning emissions of these 

pollutants from the source category. For 

existing indurating furnaces, we 

proposed emissions standards of 4.4 × 

10¥2 lb/LT for HCl and 1.2 × 10¥2 lb/ 

LT for HF. For new indurating furnaces, 

we proposed emission standards of 4.4 

× 10¥4 lb/LT for HCl and 3.3 × 10¥4 lb/ 

LT for HF. We proposed to require that 

owners or operators demonstrate 

compliance through initial and periodic 

performance testing (completed at least 

twice per 5-year permit term), 

establishing operating limits for each 

control device used to comply with the 

HCl and HF standards, and installing 

and operating continuous parameter 

monitoring systems (CPMS) to ensure 

continuous compliance with the 

standards. 

2. What comments did we receive on 

the proposed revised HCl and HF 

emission standards, and what are our 

responses? 

Comment: We received comments and 

data from industry identifying errors in 

the emissions data for the Tilden and 

Hibbing indurating furnaces submitted 

to the EPA in response to the CAA 

section 114 information request sent to 

the taconite facilities in 2022. For the 

Tilden stack test report, industry 

confirmed the units of measure were 

incorrectly listed in the stack test report 

submitted by industry as ‘‘pounds per 

ton’’ instead of ‘‘pounds per long ton’’ 

of taconite pellets produced. 

Commenters confirmed the units of 

measure should be ‘‘pounds per long 

ton.’’ For Hibbing, the commenters 

identified one transcription error in the 

HCl emissions data for one of the four 

emission stacks. 

Response: In response to these 

comments, the EPA reviewed all stack 

test runs for the seven furnaces that 

completed HCl and HF stack testing 

pursuant to the 2022 CAA section 114 

information request. We confirmed 

there was a transcription error in HCl 

emissions for the first run of the stack 

testing completed on the Hibbing 

furnace. Since the emissions data for 

Hibbing were included in the dataset 

used to calculate the proposed HCl 

emission limit, we recalculated the 

emission limit for HCl using the revised 

data. As a result of the changes to the 

Hibbing emissions data, the numerical 

emission standard for HCl for existing 

sources was revised from the proposed 

4.4 × 10¥2 lb/LT to the 4.6 × 10¥2 lb/ 

LT limit we are finalizing in this action. 

The revisions to the emissions data do 

not impact the numerical limit for HCl 

for new sources or the numerical limits 

for HF for new and existing sources. 

Therefore, the proposed HCl standard 

for new sources of 4.4 × 10¥4 lb/LT and 

the HF standards for new and existing 

sources of 3.3 × 10¥4 lb/LT and 1.2 × 

10¥2 lb/LT, respectively, are finalized 

without change. 

The EPA revised the units of measure 

for the Tilden HCl and HF emission data 

based on the comments we received 

from industry. As we explained in the 

proposal, the HCl and HF emissions 

data for the Tilden furnace are not used 

to calculate the emission limits for HCl 

and HF because Tilden’s furnaces use 

dry electrostatic precipitators (ESP). In 

the proposal, we stated that we expect 

Tilden’s two indurating furnaces would 

be able to meet the HF limit for existing 

furnaces without adding any air 

pollution control devices but that we 

expect Tilden would be required to add 

air pollution control devices to meet the 

proposed HCl emission standard. 

Although the revised emission rates for 

Tilden are slightly lower than the 

emissions rates used for the proposal, 

we expect that Tilden’s furnaces would 

still need to add air pollution controls 

to meet the HCl emission standard we 

are finalizing for existing furnaces. As 

explained in the previous paragraph, the 

EPA is finalizing the HCl emission 

standard of 4.6 × 10¥2 lb/LT for existing 

sources. To comply with the HCl 

emission standard, Tilden must reduce 

HCl emissions by 76 percent (compared 

to 79 percent HCl reduction we 

estimated at proposal) and the HCl 

emissions reduction for the final rule is 

683 tpy (compared to a 713 tpy 

reduction we estimated at proposal). 

Our revised total capital cost estimate 

for HCl controls (dry sorbent injection) 

is $1.1 million and our revised annual 

cost estimate is $1.4 million. The 

revised cost effectiveness is $2,040 per 

ton of HCl removed, which is a level of 

cost effectiveness that is acceptable for 

HCl and would also likely be acceptable 

for any other HAP. The revised 

emissions data, numerical limits, and 

cost estimates prepared for the final rule 

are documented in the memorandum, 

Final Revised Technology Review of 

Acid Gas Controls for Indurating 


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Furnaces in the Taconite Iron Ore 

Processing Source Category, which is 

available in the docket for this action. 

Comment: Multiple commenters were 

supportive of replacing PM as a 

surrogate for HCl and HF emissions and 

supported the proposed numerical 

emission limits for HCl and HF. One 

commenter said the PM limit was not a 

valid surrogate for emissions of HCl and 

HF and argued the EPA should set HCl 

and HF limits under the provisions of 

CAA section 112(d)(2) and (3). However, 

other commenters from industry 

disagreed with our proposal and said 

the existing standards based on PM as 

a surrogate for acid gases should not be 

changed. These commenters asserted 

that the EPA lacked the authority to 

revise the existing HCl and HF 

standards because the EPA had not 

shown that technological developments 

have occurred that would lower 

emissions of acid gases nor shown that 

revisions are necessary, as required by 

CAA section 112(d)(6). The commenters 

stated that new emissions data does not 

qualify as a development under CAA 

section 112(d)(6) and that the language 

in CAA section 112(d)(6) focuses on 

actual control measures and requires the 

EPA to update an existing emissions 

standard only if improvements in 

control measures occur and the 

improvements in control measures 

warrant a revision. The commenters 

added that PM is still recognized as a 

proper surrogate for HAP emissions and 

the revised standards are unnecessary 

because they impose a significant 

financial burden on taconite iron ore 

processing plants without reducing risks 

to the public health and the 

environment. 

Response: The EPA agrees that 

revising the emission limits for HCl and 

HF is appropriate for the reasons 

explained in this discussion, below, and 

in the proposal preamble (88 FR 30926). 

We disagree that the EPA lacks 

authority to revise the existing 

standards for HCl and HF. When the 

NESHAP for the Taconite Iron Ore 

Processing source category was first 

developed, PM emission limits were 

used as a surrogate for HCl and HF. The 

decision to use the PM standards as a 

surrogate for HCl and HF emissions was 

based on an analysis of the HCl, HF, and 

PM emissions data that the EPA 

possessed at the time of promulgation of 

the initial NESHAP for the Taconite Iron 

Ore Processing source category in 2003 

(68 FR 61868; October 30, 2003). That 

data indicated there was a correlation 

between acid gas and PM emissions. We 

note, however, that the use of PM as a 

surrogate for HCl and HF and the 

corresponding PM emission limit were 

based on a limited dataset because only 

three furnaces conducted PM emissions 

tests concurrently with the HCl and HF 

tests. As part of the 2022 CAA section 

114 information request, the EPA sought 

emissions data from Taconite Iron Ore 

Processing facilities, including stack 

testing for PM, HCl, and HF emissions 

from seven indurating furnaces located 

at six taconite facilities. The data 

received in response to the 2022 CAA 

section 114 information request are 

presented in the memorandum, Final 

Emissions Data Collected in 2022 for 

Indurating Furnaces Located at 

Taconite Iron Ore Processing Plants, 

which is available in the docket for this 

action. The 2022 dataset is not only 

more robust than the limited dataset 

available in 2003 but also more 

representative of current conditions 

since some of the control devices used 

on the furnaces at the time of the 2003 

rulemaking have changed since that 

time. For example, the Keetac plant has 

since replaced the multicyclones on 

their indurating furnace with venturi 

scrubbers and the Tilden plant replaced 

a wet ESP on one stack with a dry ESP. 

Based on this new data, we determined 

it was more appropriate to directly 

regulate the HAP of concern than to use 

a surrogate. Our analysis of the 2022 

data and our review of available air 

pollution controls for acid gases 

indicates that the controls we expect 

will be necessary to meet the numerical 

standards for HCl and HF are available 

and cost-effective. As we explained in 

the proposal (88 FR 30926), the new 

data received in response to the 2022 

CAA section 114 information request 

showed that indurating furnaces using 

wet scrubbers achieve better control of 

HCl and HF than furnaces using dry 

ESP. 

We disagree with commenter that we 

lack the authority to revise standards 

pursuant to CAA section 112(d)(6) 

absent a showing that the revisions 

would reduce risk. CAA section 

112(d)(6) requires the EPA to review 

and revise as necessary emission 

standards taking into account 

developments in practices, processes, 

and control technologies. This provision 

does not require the EPA to consider 

risk. We agree that the EPA has the 

discretion to consider cost when 

considering the appropriate level of 

control under CAA section 112(d)(6). 

The EPA identified dry sorbent injection 

(DSI) and wet scrubbers as a feasible 

control options and estimated the 

associated costs. We concluded that DSI 

is the lowest cost option for the 

indurating furnaces located at the 

Tilden plant. Based on this analysis, the 

EPA concluded the costs to comply with 

the numerical limits for HCl were 

justified and cost-effective and do not 

impose a significant financial burden on 

industry. The cost effectiveness was 

estimated to be $2,040 per ton of HCl 

removed, which is within the range the 

EPA has previously considered to be a 

cost-effective level of control for many 

HAP. Based on the 2022 emissions data, 

add on air pollution controls are not 

required to meet the HF emission limit. 

The standards we are finalizing in this 

action ensure HCl and HF emissions 

from all indurating furnaces in the 

source category are controlled to the 

same extent as the best performing 

indurating furnaces in the source 

category. 

Comment: Industry commenters 

stated there is no basis for changing the 

way HCl and HF emissions are 

regulated, that the EPA did not explain 

why PM cannot be used as a surrogate 

for HCl and HF emissions, and that if 

revised standards were needed, they 

should be based on the subcategories 

established in the Taconite Iron Ore 

Processing NESHAP in 2003. The 

commenters stated that the EPA should 

make determinations on whether new 

standards are necessary for each 

subcategory and then should base any 

new standards for each subcategory on 

emission data for the furnaces within 

that subcategory. The commenters 

acknowledged that CAA section 

112(d)(6) authorizes the EPA to review 

and revise as necessary the emission 

standards every 8 years, but they said 

the statute does not permit the EPA to 

develop new standards ignoring the 

existing subcategories. The commenters 

argued the Tilden facility processes a 

different type of taconite ore (i.e., 

hematite instead of magnetite) than the 

other facilities and therefore the 

furnaces at this facility should remain in 

a separate subcategory from the furnaces 

at the other facilities (as was the case 

when the EPA established the PM 

standards in the 2003 NESHAP). The 

commenters noted that a subcategory 

was established for grate kilns 

processing hematite ore because of 

differences in the ore and furnace, 

including different air flow direction 

and rates, the perpetual motion of the 

pellets inside the kiln, fineness of the 

hematite ore, tendency for the hematite 

pellets to break, and production of 

fluxed pellets that use limestone/ 

dolomite containing chloride. For 

furnaces that process magnetite, the 

commenters argued that limits for HCl 

and HF are not needed and would result 

in unnecessary compliance costs 


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without health and environmental 

benefits. 

Response: We disagree with the 

industry commenters’ assertion that the 

EPA should extend the 

subcategorization for PM standards used 

in the 2003 rulemaking and set HCl and 

HF limits only for grate kilns processing 

hematite ore. When the NESHAP for the 

Taconite Iron Ore Processing source 

category was initially developed, 

indurating furnaces were identified as 

significant sources of HCl and HF 

emissions. The NESHAP promulgated in 

2003 established limits, as required 

under CAA section 112(d), for all 

indurating furnaces. The decision to use 

the PM standards as a surrogate for HCl 

and HF emissions was based on very 

limited HCl, HF, and PM emissions data 

available and evaluated for the 2003 

rulemaking. As we explained in the 

response to the previous comment, in 

this action, we have determined it is 

more appropriate to directly regulate the 

HAP of concern (i.e., HCl and HF) than 

to use a surrogate, using the more robust 

2022 dataset now available to us. The 

data collected for this rulemaking are 

presented in the memorandum, Final 

Emissions Data Collected in 2022 for 

Indurating Furnaces Located at 

Taconite Iron Ore Processing Plants, 

which is available in the docket for this 

action. 

We disagree with commenters’ 

assertion that emission limits for acid 

gases should be established using the 

existing subcategories for PM and that 

HCl and HF standards are not necessary 

for furnaces that process magnetite ore. 

The EPA found in the 2003 NESHAP 

final rule that HCl and HF are emitted 

by all indurating furnaces and 

established standards for all types of 

indurating furnaces in the Taconite Iron 

Ore Processing source category, 

including those indurating furnaces that 

process magnetite ore. Indeed, the 

emissions data collected in response to 

the 2022 CAA section 114 information 

request demonstrate that indurating 

furnaces processing magnetite ore emit 

measurable levels of HCl and HF even 

after control by wet scrubbers. HCl and 

HF are formed in indurating furnaces 

due to the presence of chlorides and 

fluorides in the raw materials used to 

form the greenballs (i.e., unfired 

taconite pellets) that are fed into the 

indurating furnaces. While some of the 

chlorides and fluorides in the raw 

materials come from the ore, pellet 

additives, such as dolomite and 

limestone, are also a source of HCl and 

HF emissions. These additives are 

routinely used by all taconite plants, 

including those that process magnetite 

ore. Although the commenters suggested 

plants processing hematite ore using 

grate-kilns should be considered a 

separate subcategory when considering 

acid gas emissions, the commenters 

provided no data demonstrating a 

significant difference in the chloride 

and fluoride content of the two types of 

ores. Nor did they provide any 

explanation or data to support their 

assertion that differences in the design 

of the indurating furnace impact HCl 

and HF emissions. The data pertaining 

to indurating furnaces processing 

magnetite ore that was collected in 

response to the 2022 CAA section 114 

information request does not show a 

significant difference in acid gas 

emissions between straight-grate and 

grate kiln indurating furnaces. 

Pursuant to CAA section 112(d)(1), 

the Administrator ‘‘may distinguish 

among classes, types, and sizes of 

sources within a category or subcategory 

in establishing’’ standards. However, as 

we have discussed in previous Agency 

actions, the CAA does not mandate that 

the EPA create subcategories. See, e.g., 

National Emission Standards for 

Hazardous Air Pollutants From Coaland Oil-Fired Electric Utility Steam 

Generating Units and Standards of 

Performance for Fossil-Fuel-Fired 

Electric Utility, Industrial-CommercialInstitutional, and Small IndustrialCommercial-Institutional Steam 

Generating Units (77 FR 9304, 9378; 

February 16, 2012) (‘‘2012 Mercury and 

Air Toxics Final Rule’’). In addition, the 

Agency may create subcategories for the 

purpose of regulating specific HAP, 

while declining to create subcategories 

more broadly. In the 2012 Mercury and 

Air Toxics Final Rule, we explained the 

Agency’s position that any basis for 

subcategorization (i.e., class, type, or 

size) typically must be related to an 

effect on HAP emissions that is due to 

the difference in class, type, or size of 

the sources. We further explained that 

‘‘[e]ven if we determine that emissions 

characteristics are different for units 

that differ in class, type, or size, the 

Agency may still decline to 

subcategorize if there are compelling 

policy justifications that suggest 

subcategorization is not appropriate’’ 

(77 FR 9378). In the 2012 Mercury and 

Air Toxics Final Rule, we determined it 

was appropriate to subcategorize coalfired boilers for purposes of regulating 

Hg emissions based on differences in Hg 

emissions between two types of coalfired boiler subcategories. We also 

determined that for all other HAP, the 

data did not show any difference in 

HAP emission levels, and we declined 

to set separate emission standards for 

the two types of coal-fired boilers for 

other HAP. 

In this final rule, we are retaining the 

separate PM emission limits established 

in the 2003 final rule for indurating 

furnaces processing magnetite and 

hematite. Based on the data available, 

we continue to believe it is appropriate 

to retain these separate PM emission 

standards because hematite is a finer 

grained ore than magnetite, and 

processing of hematite in an indurating 

furnace results in higher PM emissions 

than processing magnetite. However, we 

are declining to subcategorize taconite 

indurating furnaces for purposes of 

regulating Hg or acid gas emissions. As 

explained previously, pursuant to CAA 

section 112(d)(1), the EPA has the 

discretion to subcategorize sources for 

the purpose of setting emission 

standards under CAA section 112, but is 

not required to do so. As we also 

explained, where the EPA elects to 

subcategorize sources, we typically do 

so for the purpose of setting standards 

for specific HAP where the basis for the 

subcategorization is related to an effect 

on HAP emissions that is due to a 

difference in class, type, or size of the 

sources. The differences in emissions of 

HCl and HF among taconite indurating 

furnaces are largely the result of 

differing controls utilized by sources 

rather than a result of the class, type, or 

size of the indurating furnaces 

themselves. Therefore, we conclude that 

the differences in HCl and HF emissions 

are not due to differences in the class, 

type, of size of taconite indurating 

furnaces. As a result, we do not believe 

it is appropriate to subcategorize 

taconite indurating furnaces for the 

purpose of regulating Hg, HCl, or HF 

emissions and are declining to do so in 

this final rule. 

Based on the data available, the EPA 

proposed to set HCl and HF emission 

standards that apply to all indurating 

furnaces. In this action, we are 

finalizing emission standards for HCl 

and HF as discussed in section III.B.1 of 

this preamble. While the HCl emission 

standard for existing furnaces differs 

from what we proposed for the reasons 

explained in section III.B.2 of this 

preamble, we continue to believe it is 

appropriate to set numerical emission 

standards for HCl and HF based on the 

2022 ICR data rather than to continue to 

rely on PM standards as a surrogate for 

these pollutants. While we expect that 

most indurating furnaces will be able to 

meet the revised HCl and HF limits 

using existing air pollution controls, the 

new performance testing and parametric 

monitoring requirements are necessary 

to ensure continuous compliance with 

the HCl and HF emission standards. The 


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PM testing and monitoring requirements 

in the current NESHAP designed to 

ensure compliance with the PM 

emission standards, which will remain 

in place as surrogates for non-Hg metal 

HAP, are not sufficient to demonstrate 

compliance with the HCl and HF 

emission standards. Each owner and 

operator must complete performance 

testing, establish operating limits for 

each control device used to control HCl 

and HF, and monitor the appropriate 

parameters to demonstrate the control 

device is operating in a manner that 

ensures compliance with the HCl and 

HF emission standards. Performance 

testing must be completed at least twice 

per 5-year permit term and within 180 

days of startup of new furnaces. 

Comment: Industry commenters 

asserted the data used to develop the 

numerical standards for HCl and HF 

was too limited to reflect the operational 

and seasonal variability in the HCl and 

HF emissions. They stated that several 

factors influence the HCl and HF 

emissions and that the emissions data 

received in response to the 2022 CAA 

section 114 information request covers 

too short of a time period to be 

representative of the acid gas emissions 

from indurating furnaces. The 

commenters noted that HCl and HF 

emissions are driven by the chloride or 

fluoride content in the iron ore and that 

the limited dataset does not account for 

the full range of variability in the 

chlorine and fluorine content of raw 

materials. They stated that the raw 

materials vary throughout a taconite 

mine, producing raw materials with 

different compositions and 

characteristics that are not reflected in 

the 2022 CAA section 114 information 

request data. The commenters 

recommended the HCl and HF limits be 

based on a more representative dataset 

collected over a longer period of time 

that accounts for raw material variation 

as well as seasonal and operational 

variation. The commenters stated that 

because the proposed limits are based 

on a limited dataset that does not fully 

account for operational variability, the 

proposed HCl and HF emission limits 

should not be finalized and they 

recommended that the PM standards in 

the current NESHAP continue to be 

used as a surrogate for acid gas 

emissions. 

Response: The method used to 

calculate the proposed numeric 

emission limits for HCl and HF for new 

and existing taconite indurating 

furnaces has been used for several years 

to set numerical limits for other source 

categories and is an appropriate 

methodology that accounts for 

variability in the emissions between 

different furnaces and different plants 

and accounts for some variability in the 

chloride and fluoride content of the ore 

and pellet additives used at different 

facilities because it includes data from 

two different types of indurating 

furnaces (straight grate furnaces and 

grate kiln furnaces) at five different 

taconite facilities. We used the 

emissions data from the six indurating 

furnaces currently using wet scrubbers 

to calculate a UPL. The UPL approach 

encompasses all the data point-to-data 

point variability within the sample set 

(i.e., all of the emissions data from the 

six indurating furnaces equipped with 

wet venturi scrubbers), which consisted 

of 21 individual data points. The UPL 

was calculated as the mean of the 21 

data points plus a factor that accounts 

for the variability within the dataset. 

The UPL represents the value which one 

can expect the mean of a specified 

number of future observations (e.g., 3- 

run average) to fall below at a specified 

level of confidence based upon the 

results of an independent sample from 

the same population. We used a 99- 

percent level of confidence to calculate 

the UPL, which means that a facility 

that uses the same or similar type of air 

pollution control device(s) has one 

chance in 100 of exceeding the emission 

limit. A prediction interval for a single 

future observation (or an average of 

several test observations) is an interval 

that will, with a specified degree of 

confidence, contain the next (or the 

average of some other pre-specified 

number of) randomly selected 

observation(s) from a population. The 

UPL estimates what the upper bound of 

future values will be based upon present 

or past background samples taken. 

While larger datasets are always 

preferable, numerical emission limits 

are often based on data from a single 

stack test event. For additional 

information on the methodology used to 

develop the numerical emission 

standards for HCl and HF for the final 

rule, please see the memorandum, Final 

Revised Technology Review of Acid Gas 

Controls for Indurating Furnaces in the 

Taconite Iron Ore Processing Source 

Category. A copy of this document is 

available in the docket for this action. 

3. What are the revised standards for 

HCl and HF and how will compliance 

be demonstrated? 

We are finalizing numerical emission 

limits for HCl and HF, pursuant to CAA 

section 112(d)(6). We are finalizing as 

proposed the numerical emission limit 

for HCl for new indurating furnaces. We 

are finalizing a numerical emission limit 

for HCl for existing indurating furnaces 

which differs from the limit proposed 

because the final limit reflects a revision 

to the emissions data for the Hibbing 

facility, as discussed in section III.B.2 of 

this preamble. We are finalizing as 

proposed the numerical emission limits 

for HF for new and existing indurating 

furnaces. For existing indurating 

furnaces, we are finalizing an HCl 

emission limit of 4.6 × 10¥2 lb/LT and 

are finalizing an HF emission limit of 

1.2 × 10¥2 lb/LT. For new indurating 

furnaces, we are finalizing an HCl 

emission limit of 4.4 × 10¥4 lb/LT and 

are finalizing an HF emission limit of 

3.3 × 10¥4 lb/LT. Further discussion of 

the HCl and HF emission standards and 

the methodology used to develop the 

emission standards, as well as a 

discussion of costs, may be found in the 

memorandum, Final Revised 

Technology Review of Acid Gas Controls 

for Indurating Furnaces in the Taconite 

Iron Ore Processing Source Category, 

which is available in the docket for this 

action. 

We are also finalizing as proposed the 

requirement to complete performance 

testing for HCl and HF using EPA 

Method 26A and to establish operating 

limits for each control device used to 

comply with the HCl and HF standards, 

in accordance with the amended 

provisions of 40 CFR 63.9622. The final 

rule clarifies that the owner or operator 

must perform performance testing when 

the pellet production rate is equal to or 

greater than 90 percent of the capacity 

of the indurating furnace. If the 

performance testing cannot be 

performed at or above 90 percent of 

capacity of the indurating furnace, the 

owner or operator may complete testing 

at a lower production rate if they receive 

approval from the delegated authority. 

The owner or operator must install and 

operate CPMS in accordance with the 

requirements of 40 CFR 63.9633 and 

must prepare a preventive maintenance 

plan and keep records of calibration and 

accuracy checks of the CPMS to 

document proper operation and 

maintenance of each monitoring system. 

An owner or operator must take 

corrective action when an established 

operating limit is exceeded. The owner 

or operator must complete the initial 

performance tests within 180 calendar 

days of the compliance date for existing 

furnaces, or within 180 calendar days of 

startup for new furnaces. The 

performance tests must be repeated at 

least twice per 5-year permit term. 


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4Association of Battery Recyclers v. EPA, 716 

F.3d 667, 672 (D.C. Cir. 2013) (‘‘Section 112(i)(3)’s 

3-year maximum compliance period applies 

generally to any emission standard . . . 

promulgated under [section 112]’’ (brackets in 

original)). 

C. What other amendments are we 

finalizing? 

1. Requirement To Complete 

Performance Testing Within 7 Calendar 

Days 

The EPA proposed amendments to the 

performance testing provisions that 

would require the owner or operator to 

complete a performance test on a source 

within 7 calendar days of initiating that 

performance test. This provision was 

included for the existing performance 

testing for PM, as well as for the 

proposed new performance testing for 

Hg, HCl, and HF. We received one 

comment that resulted in changes to the 

proposed requirements. The comment 

and our response are summarized 

below. 

Comments: Industry commenters 

opposed the proposed requirement that 

all performance testing be completed 

within 7 calendar days because some 

emission sources have multiple stacks 

and testing of multiple stacks could 

require more than 7 days to complete. 

They also stated that unanticipated 

shutdowns due to process upsets may 

prevent tests from being completed 

within 7 days. The commenters 

recommended that the EPA allow 

facilities to notify the Administrator 

when a longer time frame is needed but 

asserted that facilities should not be 

required to obtain approval if more than 

7 calendar days are needed to complete 

performance testing. 

Response: We consider the 7 calendar 

day period to complete all performance 

testing to be reasonable based on our 

previous experience with performance 

testing at industrial facilities. We 

believe it is unlikely that a facility 

would be unable to complete the 

required performance testing within a 7 

calendar day timeframe. However, we 

acknowledge the commenters’ concerns 

that unanticipated shutdowns can occur 

due to equipment failures or process 

upsets. To address such circumstances, 

we included the phrase ‘‘to the extent 

practicable’’ in the final rule. We have 

finalized the proposed requirement that 

performance tests be completed within 

7 calendar days of the date on which the 

first test run was started. However, we 

agree with the commenters’ suggestion 

that owners and operators be required to 

notify the Administrator when a 

performance test cannot be completed 

within 7 calendar days. In the final rule, 

we revised the proposed language in 40 

CFR 63.9620(b)(2), 63.9620(k)(2), and 

63.9630(b) to require facilities that will 

not be able to complete performance 

tests within 7 calendar days to notify 

the Administrator within 24 hours of 

making the determination that they will 

not be able to do so. 

2. Amendments to the Electronic 

Reporting Requirements 

We are also finalizing as proposed 

changes to the electronic reporting 

requirements found in 40 CFR 

63.9641(c) and 40 CFR 63.9641(f)(3) to 

reflect new procedures for reporting 

CBI, including adding an email address 

that an owner or operator may use to 

electronically submit compliance 

reports containing CBI to the OAQPS 

CBI Office. We received no comments 

on these proposed amendments. 

D. What are the effective and 

compliance dates for the mercury, HCl, 

and HF emission standards? 

The revisions to the MACT standards 

promulgated in this action are effective 

on March 6, 2024. For all affected 

sources that commence construction or 

reconstruction before May 15, 2023, we 

are finalizing, as proposed, that an 

owner or operator must comply with the 

new Hg emission standard and revised 

HCl and HF standards no later than 3 

years after the effective date of the final 

rule. For all affected sources that 

commenced construction or 

reconstruction on or after May 15, 2023, 

we are finalizing, as proposed, that 

owners and operators comply with 

provisions by the effective date of the 

final rule or upon startup, whichever is 

later. For existing sources, CAA section 

112(i)(3) requires compliance ‘‘as 

expeditiously as practicable, but in no 

event later than 3 years after the 

effective date of such standard’’ subject 

to certain exemptions further detailed in 

the statute.4 In determining what 

compliance period is as ‘‘expeditious as 

practicable,’’ we examine the amount of 

time needed to plan and construct 

projects and change operating 

procedures. Since some existing sources 

may need to install new add-on controls 

to comply with the Hg, HCl, and/or HF 

standards, we determined that a period 

of 3 years is appropriate to allow owners 

and operators time to plan, design, 

construct, begin operating the new addon controls, and conduct performance 

testing. 

IV. Summary of Cost, Environmental, 

and Economic Impacts 

A. What are the affected sources? 

The Taconite Iron Ore Processing 

NESHAP applies to the owner or 

operator of a taconite iron ore 

processing plant that is (or is part of) a 

major source of HAP emissions. A 

taconite iron ore processing plant is any 

facility engaged in separating and 

concentrating iron ore from taconite ore 

to produce taconite pellets. Taconite 

iron ore processing includes the 

following processes: liberation of the 

iron ore by wet or dry crushing and 

grinding in gyratory crushers, cone 

crushers, rod mills, and ball mills; 

concentration of the iron ore by 

magnetic separation or flotation; 

pelletizing by wet tumbling with a 

balling drum or balling disc; induration 

using a straight grate or grate kiln 

indurating furnace; and finished pellet 

handling. A major source of HAP is a 

plant site that emits, or has the potential 

to emit, any single HAP at a rate of 9.07 

megagrams (10 tons) or more, or any 

combination of HAP at a rate of 22.68 

megagrams (25 tons) or more per year 

from all emission sources at the plant 

site. There are currently seven major 

sources subject to the Taconite Iron Ore 

Processing NESHAP that are operating 

in the United States with six located in 

Minnesota and one located in Michigan. 

One additional major source located in 

Michigan, Empire Mining, is subject to 

the Taconite Iron Ore Processing 

NESHAP and has a permit to operate 

but has been indefinitely idled since 

2016. 

B. What are the air quality impacts? 

To meet the Hg emission limits we 

anticipate that five of the taconite iron 

ore processing plants would likely need 

to install additional controls on their 

indurating furnaces. To meet the HCl 

and HF emission limits, we anticipate 

that one additional taconite iron ore 

processing plant would likely need to 

install additional controls on their 

indurating furnaces. We estimate that 

the installation of such controls will 

reduce Hg emissions by 247 pounds per 

year (0.12 tpy) and HCl and HF 

emissions by 683 tpy and 36 tpy, 

respectively. 

Indirect or secondary air emissions 

impacts are impacts that would result 

from the increased electricity usage 

associated with the operation of control 

devices (e.g., increased secondary 

emissions of criteria pollutants from 

power plants). Energy impacts consist of 

the electricity and steam needed to 

operate control devices and other 

equipment. As explained in the 

memorandum, Development of Impacts 

for the Final Amendments to the 

NESHAP for Taconite Iron Ore 

Processing, which is available in the 

docket for this action, we find that the 

secondary air emissions impacts of this 


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5U.S. EPA, 2022. Estimating PM2.5- and OzoneAttributable Health Benefits. Office of Air and 

Radiation, Research Triangle Park, NC. 

6U.S. EPA (2023). Technical Support Document 

Estimating the Benefit per Ton of Reducing 

Directly-Emitted PM2.5, PM2.5 Precursors and Ozone 

Precursors from 21 Sectors. Research Triangle Park, 

NC: U.S. Environmental Protection Agency, Office 

of Air Quality Planning and Standards, Health and 

Environmental Impact Division. Available at: 

https://www.epa.gov/system/files/documents/2021- 

10/source-apportionment-tsd-oct-222021_0.pdf. 

7U.S. EPA, 2024. Economic Impact Analysis for 

the Final National Emission Standards for 

Hazardous Air Pollutants: Taconite Iron Ore 

Processing Amendments. Office of Air and 

Radiation, Research Triangle Park, NC. 8https://www.epa.gov/environmentaljustice. 

action are minimal. The memorandum 

includes a detailed discussion of our 

analysis of emissions reductions and 

potential secondary impacts. 

This rule is expected to limit 

emissions of directly emitted PM2.5, 

which will in turn reduce ambient 

concentrations of PM2.5 and in turn 

benefit public health. Though EPA 

neither quantified nor monetized these 

benefits, we anticipate reducing PM2.5

concentrations will reduce the 

incidence or premature death, non-fatal 

heart attacks, cases of aggravated 

asthma, lost days of work and school 

and other adverse effects (U.S. EPA, 

2022).5 EPA has generated benefit per 

ton estimates for directly emitted PM2.5

reductions from the taconite sector 

valued at $60,600/ton (2016$).6 In 

addition, there are estimates for 

secondarily-formed PM2.5 from 

reductions in SO2 emissions valued at 

$32,800/ton (2016$). However, EPA did 

not conduct a comprehensive benefitcost analysis for this rulemaking. This 

rule is also expected to reduce 

emissions of Hg. Methylmercury 

(MeHg), which is formed by microbial 

action in the top layers of sediment and 

soils, after mercury has precipitated 

from the air and deposited into 

waterbodies or land, is known to cause 

a number of adverse effects. Though not 

quantified here, these effects include IQ 

loss measured by performance on 

neurobehavioral tests, particularly on 

tests of attention, fine motor-function, 

language, and visual spatial ability. 

C. What are the cost impacts? 

We estimate the total capital and 

annualized costs of this final rule for 

existing sources in the Taconite Iron Ore 

Processing source category will be 

approximately $106 million and $68 

million per year, respectively. The 

annual costs are based on operation and 

maintenance of added control systems. 

Although this action also finalizes 

standards for new sources, we are not 

aware of any new sources being 

constructed now or planned for the 

future. No new indurating furnaces have 

been constructed, reconstructed or 

modified in more than a decade and the 

domestic demand for taconite pellets 

has decreased over the past several 

decades caused by the increasing use of 

electric arc furnaces.7 Consequently, we 

did not estimate any cost impacts for 

new sources. The memorandum, 

Development of Impacts for the Final 

Amendments to the NESHAP for 

Taconite Iron Ore Processing, includes 

details of our cost assessment, expected 

emission reductions and estimated 

secondary impacts. A copy of this 

memorandum is available in the docket 

for this action. 

D. What are the economic impacts? 

The EPA assessed the potential 

economic impacts of this action by 

comparing the expected annual cost for 

operating the air pollution control 

devices to the total sales revenue for the 

ultimate owners of affected facilities. 

The expected annual cost is $10.2 

million (on average) for each facility 

that needs air pollution controls to 

comply with the standards, with an 

estimated nationwide annual cost of $61 

million per year. The six affected 

facilities are owned by two parent 

companies (U.S. Steel and ClevelandCliffs, Inc.). Neither parent company 

qualifies as a small business, and the 

total costs associated with this final rule 

are expected to be less than 1 percent 

of annual sales revenue per ultimate 

owner. 

The EPA also modeled the economic 

impacts of the final rule using two 

standard partial equilibrium economic 

models: one for taconite iron ore pellets 

and one for steel mill products. The 

EPA linked these two partial 

equilibrium models by specifying 

interactions between supply and 

demand in both markets and solving for 

changes in prices and quantity across 

both markets simultaneously. These 

models use baseline economic data from 

2019 to project the impact of the final 

rule on the market for taconite iron ore 

pellets and steel mill products. The 

models allow the EPA to project facilityand market-level price and quantity 

changes for taconite iron ore pellets and 

market-level price and quantity changes 

for steel mill products, including 

changes in imports and exports in both 

markets. The models project a 0.28 

percent fall in the quantity of 

domestically produced taconite iron ore 

pellets along with a 0.63 percent 

increase in their price. The models also 

project a 0.02 percent fall in the 

quantity of domestically produced steel 

mill products along with an 0.01 

percent increase in their price. Details of 

our economic impact estimates for 

sources in the Taconite Iron Ore 

Processing source category may be 

found in the document, Economic 

Impact Analysis for the Final National 

Emission Standards for Hazardous Air 

Pollutants: Taconite Iron Ore Processing 

Amendments (EIA), which is available 

in the docket for this action. 

E. What analysis of environmental 

justice did we conduct? 

Consistent with the EPA’s 

commitment to integrating 

environmental justice (EJ) into the 

Agency’s actions, and following the 

directives set forth in multiple executive 

orders, the EPA evaluated the impacts of 

this action on communities with EJ 

concerns. Overall, we found that in the 

population living in close proximity 

(within 10 kilometers (km)) of facilities, 

the following demographic groups were 

above the national average: White, 

Native American, and people living 

below the poverty level. The EPA 

defines EJ as ‘‘the fair treatment and 

meaningful involvement of all people 

regardless of race, color, national origin, 

or income, with respect to the 

development, implementation, and 

enforcement of environmental laws, 

regulations, and policies.’’ 8 The EPA 

further defines fair treatment to mean 

that ‘‘no group of people should bear a 

disproportionate burden of 

environmental harms and risks, 

including those resulting from the 

negative environmental consequences of 

industrial, governmental, and 

commercial operations or programs and 

policies.’’ 

For the Taconite Iron Ore Processing 

source category, the EPA examined the 

potential for EJ concerns by conducting 

a proximity demographic analysis for 

the eight existing taconite iron ore 

processing plants (seven operating 

plants and one indefinitely idled). The 

proximity demographic analysis is an 

assessment of individual demographic 

groups in the total population living 

within 10 km and 50 km of the facilities. 

The EPA compared the data from this 

analysis to the national average for each 

of the demographic groups. Since the 

taconite iron ore processing facilities are 

very large, a radius of 10 km was used 

as the near facility distance for the 

proximity analysis. A distance closer 

than 10 km does not yield adequate 

population size for the results. A 

summary of the proximity demographic 

assessment was included in Table 5 in 

the proposal for this rulemaking (88 FR 

30931; May 15, 2023). The results show 

that for the population living within 10 


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km of the eight facilities, the following 

demographic groups were above the 

national average: White (93 percent 

versus 60 percent nationally), Native 

American (0.8 percent versus 0.7 

percent nationally), and people living 

below the poverty level (15 percent 

versus 13 percent nationally). For two 

facilities (the UTAC and Minntac 

facilities), the percentage of the 

population living within 10 km that is 

Native American (1.9 percent and 2.3 

percent) was more than double the 

national average (0.7 percent). For four 

facilities (Keetac, Hibbing, Minorca, and 

Minntac) the percentage of the 

population living within 10 km that is 

low-income is above the national 

average. The results of the proximity 

analysis are in the technical report, 

Analysis of Demographic Factors For 

Populations Living Near Taconite Iron 

Ore Processing Source Category 

Operations, which is available in the 

docket for this action. 

This action sets new standards for Hg 

and revised standards for HCl and HF 

that will reduce the annual emissions of 

these HAP from taconite facilities. The 

Hg standards will reduce the health, 

environmental and cultural impacts of 

Hg identified by tribes in their 

comments by requiring the five taconite 

facilities (UTAC, Keetac, Hibbing, 

Minorca, and Minntac) that have nearby 

Native American populations and lowincome populations above the national 

averages to reduce Hg emissions by up 

to 247 pounds per year (0.12 tpy). The 

emission limits must be met at all times 

(including periods of startup, shutdown, 

and malfunctions) and compliance must 

be demonstrated through monitoring of 

control device operating parameters and 

either periodic testing or CEMS. 

V. Statutory and Executive Order 

Reviews 

Additional information about these 

statutes and Executive Orders can be 

found at https://www.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action is a ‘‘significant regulatory 

action’’ as defined in Executive Order 

12866, as amended by Executive Order 

14094. Accordingly, the EPA submitted 

this action to the Office of Management 

and Budget (OMB) for Executive Order 

12866 review. Documentation of any 

changes made in response to the 

Executive Order 12866 review is 

available in the docket. The EPA 

prepared an economic analysis of the 

potential impacts associated with this 

action. This analysis is summarized in 

section IV.D of this preamble and in the 

document Economic Impact Analysis 

for the Final National Emission 

Standards for Hazardous Air Pollutants: 

Taconite Iron Ore Processing 

Amendments, available in Docket ID 

No. EPA–HQ–OAR–2017–0664. 

B. Paperwork Reduction Act (PRA) 

The information collection activities 

in this rule have been submitted for 

approval to the OMB under the PRA. 

The ICR document that the EPA 

prepared has been assigned EPA ICR 

number 2050.10, OMB Control Number 

2060–0538. You can find a copy of the 

ICR in the docket for this action, and it 

is briefly summarized here. The 

information collection requirements are 

not enforceable until OMB approves 

them. 

In this action, we are finalizing 

changes to the reporting and 

recordkeeping requirements for the 

Taconite Iron Ore Processing NESHAP 

by incorporating reporting and 

recordkeeping requirements for the new 

MACT standards for Hg and the revised 

emission standards for HCl and HF. 

Respondents/affected entities: 

Owners or operators of taconite iron ore 

plants that are major sources, or that are 

located at, or are part of, major sources 

of HAP emissions. 

Respondent’s obligation to respond: 

Mandatory (40 CFR part 63, subpart 

RRRRR). 

Estimated number of respondents: On 

average over the next 3 years, 

approximately seven existing major 

sources will be subject to these 

standards. It is also estimated that no 

additional respondent will become 

subject to the emission standards over 

the 3-year period. 

Frequency of response: The frequency 

of responses varies depending on the 

burden item. 

Total estimated burden: The average 

annual burden to industry over the next 

3 years from the new recordkeeping and 

reporting requirements is estimated to 

be 1,580 hours per year. Burden is 

defined at 5 CFR 1320.3(b). 

Total estimated cost: The annual 

recordkeeping and reporting costs for all 

facilities to comply with all the 

requirements in the NESHAP is 

estimated to be $185,000 per year. The 

average annual recordkeeping and 

reporting cost for this rulemaking is 

estimated to be $26,500 per facility per 

year. The operation and maintenance 

costs are estimated to be $18 million per 

year. 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to, a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for the EPA’s regulations in 40 

CFR are listed in 40 CFR part 9. When 

OMB approves this ICR, the Agency will 

announce that approval in the Federal 

Register and publish a technical 

amendment to 40 CFR part 9 to display 

the OMB control number for the 

approved information collection 

activities contained in this final rule. 

C. Regulatory Flexibility Act (RFA) 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. This action will not 

impose any requirements on small 

entities. The Agency confirmed through 

responses to a CAA section 114 

information request that there are only 

seven taconite iron ore processing 

plants currently operating in the United 

States and that these plants are owned 

by two parent companies that do not 

meet the definition of small businesses, 

as defined by the U.S. Small Business 

Administration. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This action does not contain an 

unfunded mandate of $100 million or 

more as described in UMRA, 2 U.S.C. 

1531–1538, and does not significantly or 

uniquely affect small governments. This 

action imposes no enforceable duty on 

any state, local, or Tribal governments 

or the private sector. 

E. Executive Order 13132: Federalism 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the states, on the 

relationship between the National 

Government and the states, or on the 

distribution of power and 

responsibilities among the various 

levels of government. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have Tribal 

implications as specified in Executive 

Order 13175. The Executive Order 

defines Tribal implications as ‘‘actions 

that have substantial direct effects on 

one or more Indian Tribes, on the 

relationship between the Federal 

Government and Indian tribes, or on the 

distribution of power and 

responsibilities between the Federal 

Government and Indian tribes.’’ The 

amendments in this action would not 

have a substantial direct effect on one or 

more tribes, change the relationship 

between the Federal Government and 

tribes, or affect the distribution of power 


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Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16423 

and responsibilities between the Federal 

Government and Indian Tribes. Thus, 

Executive Order 13175 does not apply 

to this action. 

Although this action does not have 

Tribal implications as defined by 

Executive Order 13175, consistent with 

the EPA Policy on Consultation and 

Coordination with Indian Tribes, the 

EPA consulted with Tribal officials 

during the development of this action. 

On January 12, 2022, the EPA’s Office 

of Air and Radiation held a Tribal 

consultation meeting with the Fond du 

Lac Band of Lake Superior Chippewa 

Reservation and the Leech Lake Band of 

Ojibwe Reservation to discuss the EPA’s 

2022 CAA section 114 information 

request and to ensure that the views of 

tribes were taken into consideration in 

the rulemaking process in accordance 

with the EPA Policy on Consultation 

and Coordination with Indian Tribes 

(May 4, 2011) and the EPA Policy on 

Consultation and Coordination with 

Indian Tribes: Guidance for Discussing 

Tribal Treaty Rights (February 2016). A 

summary of the meeting may be found 

in the document, Consultation with the 

Fond du Lac Band of Lake Superior 

Chippewa and the Leech Lake Band of 

Ojibwe regarding Notice of Proposed 

Rulemaking for the National Emission 

Standards for Hazardous Air Pollutants 

for Taconite Iron Ore Processing 

Amendments on January 12, 2022, 

which is available in the docket for this 

action. In addition, the EPA’s staff 

attended several meetings hosted by the 

Minnesota Pollution Control Agency 

(MPCA), along with representatives 

from Tribal Nations, MPCA, the 

Michigan Attorney General’s Office, the 

Minnesota Attorney General’s Office, 

Earthjustice, and the Michigan 

Department of Environment, Great 

Lakes, and Energy, to discuss concerns 

related to HAP emissions from taconite 

iron ore processing facilities. The EPA 

also received letters from 

representatives of the Leech Lake Band 

of Ojibwe and the Fond du Lac Band of 

Lake Superior Chippewa expressing 

concerns of these Tribal Nations due to 

HAP emissions from the taconite iron 

ore processing facilities. Copies of these 

letters, as well as the EPA’s responses to 

them, are available in the docket for this 

action. 

G. National Technology Transfer and 

Advancement Act (NTTAA) and 1 CFR 

Part 51 

This action involves technical 

standards. Therefore, the EPA 

conducted searches for the Taconite 

Iron Ore Processing NESHAP through 

the Enhanced National Standards 

Systems Network (NSSN) Database 

managed by the American National 

Standards Institute (ANSI). We also 

conducted a review of VCS 

organizations and accessed and 

searched their databases. We conducted 

searches for EPA Methods 1, 1A, 2, 2A, 

2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 5, 5D, 17, 

26A, 29 and 30B. During the VCS 

search, if the title or abstract (if 

provided) of the VCS described 

technical sampling and analytical 

procedures that are similar to the EPA’s 

reference method, the EPA ordered a 

copy of the standard and reviewed it as 

a potential equivalent method. We 

reviewed all potential standards to 

determine the practicality of the VCS for 

this rule. This review requires 

significant method validation data that 

meet the requirements of EPA Method 

301 for accepting alternative methods or 

scientific, engineering, and policy 

equivalence to procedures in the EPA 

referenced methods. The EPA may 

reconsider determinations of 

impracticality when additional 

information is available for any 

particular VCS. 

No VCS were identified for EPA 

Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 

3, 3A, 4, 5, 5D, 17 or 26A. One VCS was 

identified as an acceptable alternative to 

EPA Methods 3B, 29 and 30B. 

The EPA is allowing use of the VCS 

ASTM D6784–16, ‘‘Standard Test 

Method for Elemental, Oxidized, 

Particle-Bound and Total Mercury in 

Flue Gas Generated from Coal-Fired 

Stationary Sources (Ontario Hydro 

Method)’’ as an acceptable alternative to 

EPA Method 29 (Hg portion only) as a 

method for measuring Hg 

concentrations ranging from 

approximately 0.5 to 100 micrograms 

per normal cubic meter (mg/Nm3). This 

test method describes equipment and 

procedures for obtaining samples from 

effluent ducts and stacks, equipment 

and procedures for laboratory analysis, 

and procedures for calculating results. 

VCS ASTM D6784–16 allows for 

additional flexibility in the sampling 

and analytical procedures from the 

earlier version of the same standard VCS 

ASTM D6784–02 (Reapproved 2008). 

VCS ASTM D6784–16 allows for the use 

of either an EPA Method 17 sampling 

configuration with a fixed (single) point 

where the flue gas is not stratified, or an 

EPA Method 5 sampling configuration 

with a multi-point traverse. For this 

action, only the EPA Method 5 sampling 

configuration with a multi-point 

traverse can be used. This method is 

available at ASTM International, 100 

Barr Harbor Drive, P.O. Box C700, West 

Conshohocken, PA 19428–2959. See 

https://www.astm.org/. The standard is 

available to everyone at a cost 

determined by ASTM ($82). The cost of 

obtaining this method is not a 

significant financial burden, making the 

method reasonably available. Additional 

detailed information on the VCS search 

and determination can be found in the 

memorandum, Voluntary Consensus 

Standard Results for National Emission 

Standards for Hazardous Air Pollutants: 

Taconite Iron Ore Processing, which is 

available in the docket for this action. 

The EPA solicited comment on 

potentially applicable VCS in the 

proposal for this rule. However, no 

other VCS were identified. The EPA is 

finalizing as proposed incorporating by 

reference the VCS ASTM D6784–16, 

‘‘Standard Test Method for Elemental, 

Oxidized, Particle-Bound and Total 

Mercury in Flue Gas Generated from 

Coal-Fired Stationary Sources (Ontario 

Hydro Method),’’ as an acceptable 

alternative to EPA Method 29 (Hg 

portion only). 

H. 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 

The EPA believes that the human 

health or environmental conditions that 

exist prior to this action result in or 

have the potential to result in 

disproportionate and adverse human 

health or environmental effects on 

communities with EJ concerns. The 

assessment of populations in close 

proximity of taconite iron ore 

processing plants shows Native 

American and low-income populations 

are higher than the national average (see 

section IV.E of this preamble). The 

higher percentages of Native American 

populations are near the UTAC and 

Minntac facilities. The higher 

percentages of low-income populations 

are near the Keetac, Hibbing, Minorca, 

and Minntac facilities. The EPA believes 

that this action is likely to reduce 

existing disproportionate and adverse 

effects on low-income populations and/ 

or indigenous peoples. The EPA is 

finalizing new MACT standards for Hg 

and revised standards for HCl and HF. 

The EPA expects that at least five 

facilities would have to implement 

control measures to reduce Hg 

emissions to comply with the new Hg 

MACT standard (including the UTAC, 

Keetac, Hibbing, Minorca and Minntac 

facilities) and one facility would need to 

implement control measures to reduce 

HCl emissions to comply with the 

revised standard for HCl (the Tilden 

facility). HAP exposures for indigenous 

peoples and low-income individuals 


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living near these six facilities would 

decrease. The methodology and the 

results of the demographic analysis are 

available in the docket for this action in 

the technical report Analysis of 

Demographic Factors For Populations 

Living Near Taconite Iron Ore 

Processing Source Category Operations. 

I. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

Executive Order 13045 (62 FR 19885; 

April 23, 1997) directs Federal agencies 

to include an evaluation of the health 

and safety effects of the planned 

regulation on children in Federal health 

and safety standards and explain why 

the regulation is preferable to 

potentially effective and reasonably 

feasible alternatives. This action is not 

subject to Executive Order 13045 

because it is not significant as defined 

in Executive Order 12866(3)(f)(1), and 

because the EPA does not believe the 

environmental health or safety risks 

addressed by this action present a 

disproportionate risk to children. In 

2020, the EPA conducted a residual risk 

assessment and determined that risk 

from the Taconite Iron Ore Processing 

source category was acceptable, and the 

standards provided an ample margin of 

safety to protect public health (see 85 

FR 45476 and Docket ID No. EPA–HQ– 

OAR–2017–0664–0163). For this 

rulemaking, we updated that risk 

analysis using new emissions data that 

the EPA received for some HAP 

emissions sources at the taconite 

facilities. We determined that these new 

HAP emissions estimates would not 

significantly change our previous 

estimates of the human health risk 

posed by the Taconite Iron Ore 

Processing source category. In this 

action the EPA is promulgating new 

emission standards for one previously 

unregulated pollutant (Hg) and revised 

emissions standards for two currently 

regulated pollutants (HCl and HF). 

These emissions standards will reduce 

Hg, HCl and HF emissions and thereby 

reduce children’s exposure to these 

harmful HAP. We estimate that the 

installation of controls will reduce HCl 

and HF emissions by 683 tpy and 36 

tpy, respectively, and will reduce Hg 

emissions by up to 247 pounds per year 

(0.12 tpy). 

This action’s health and risk 

assessments are protective of the most 

vulnerable populations, including 

children, due to how we determine 

exposure and through the health 

benchmarks that we use. Specifically, 

the risk assessments we perform assume 

a lifetime of exposure, in which 

populations are conservatively 

presumed to be exposed to airborne 

concentrations at their residence 

continuously, 24 hours per day for a 70- 

year lifetime, including childhood. With 

regards to children’s potentially greater 

susceptibility to noncancer toxicants, 

the assessments rely on the EPA’s (or 

comparable) hazard identification and 

dose-response values that have been 

developed to be protective for all 

subgroups of the general population, 

including children. For more 

information on the risk assessment 

methods, see the risk report for the July 

28, 2020, final Taconite residual risk 

and technology review (RTR) rule (85 

FR 45476), which is available in the 

docket. Therefore, the rulemaking 

finalizes actions that will result in 

health benefits to children by reducing 

the level of HAP emissions emitted from 

taconite iron ore processing plants. 

J. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not a ‘‘significant 

energy action’’ because it is not likely to 

have a significant adverse effect on the 

supply, distribution or use of energy. 

We have concluded that this action is 

not likely to have any adverse energy 

effects because it contains no regulatory 

requirements that will have an adverse 

impact on productivity, competition, or 

prices in the energy sector. 

K. Congressional Review Act (CRA) 

This action is subject to the CRA, and 

the EPA will submit a rule report to 

each House of the Congress and to the 

Comptroller General of the United 

States. This action is not a ‘‘major rule’’ 

as defined by 5 U.S.C. 804(2). 

List of Subjects in 40 CFR Part 63 

Environmental protection, air 

pollution control, hazardous substances, 

incorporation by reference, mercury, 

hydrogen chloride, hydrogen fluoride, 

reporting and recordkeeping 

requirements. 

Michael S. Regan, 

Administrator. 

For the reasons stated in the 

preamble, title 40, chapter I of the Code 

of Federal Regulations is amended as 

follows: 

PART 63—NATIONAL EMISSION 

STANDARDS FOR HAZARDOUS AIR 

POLLUTANTS FOR SOURCE 

CATEGORIES 

■ 1. The authority citation for part 63 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart A—General Provisions 

■ 2. Section 63.14 is amended by 

revising paragraph (i)(104) to read as 

follows: 

§ 63.14 Incorporation by reference 

* * * * * 

(i) * * * 

(104) ASTM D6784–16, Standard Test 

Method for Elemental, Oxidized, 

Particle-Bound and Total Mercury in 

Flue Gas Generated from Coal-Fired 

Stationary Sources (Ontario Hydro 

Method), Approved March 1, 2016; IBR 

approved for §§ 63.9621(d); table 5 to 

subpart UUUUU; appendix A to subpart 

UUUUU. 

Subpart RRRRR—National Emission 

Standards for Hazardous Air 

Pollutants: Taconite Iron Ore 

Processing 

■ 3. Section 63.9583 is revised and 

republished to read as follows: 

§ 63.9583 When do I have to comply with 

this subpart? 

(a) If you have an existing affected 

source, you must comply with each 

emission limitation, work practice 

standard, and operation and 

maintenance requirement in this 

subpart that applies to you no later than 

October 30, 2006, except as specified in 

paragraph (f) of this section. 

(b) If you have a new affected source 

and its initial startup date is on or 

before October 30, 2003, you must 

comply with each emission limitation, 

work practice standard, and operation 

and maintenance requirement in this 

subpart that applies to you by October 

30, 2003, except as specified in 

paragraph (f) of this section. 

(c) If you have a new affected source 

and its initial startup date is after 

October 30, 2003, you must comply 

with each emission limitation, work 

practice standard, and operation and 

maintenance requirement in this 

subpart that applies to you upon initial 

startup, except as specified in paragraph 

(f) of this section. 

(d) If your taconite iron ore processing 

plant is an area source that becomes a 

major source of HAP, the compliance 

dates in paragraphs (d)(1) and (2) of this 

section apply to you. 

(1) Any portion of the taconite iron 

ore processing plant that is a new 

affected source or a new reconstructed 

source must be in compliance with this 

subpart upon startup. 

(2) All other parts of the taconite iron 

ore processing plant must be in 

compliance with this subpart no later 

than 3 years after the plant becomes a 

major source. 


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(e) You must meet the notification 

and schedule requirements in § 63.9640. 

Several of these notifications must be 

submitted before the compliance date 

for your affected source. 

(f) If you have an affected indurating 

furnace that commenced construction 

before May 15, 2023, you must comply 

with the requirements in paragraphs 

(f)(1) through (7) of this section by 

March 8, 2027. If you have an affected 

indurating furnace that commenced 

construction or reconstruction on or 

after May 15, 2023, you must comply 

with the requirements in paragraphs 

(f)(1) through (7) of this section by 

March 6, 2024 or the date of initial 

startup, whichever is later. 

(1) All applicable emission limits for 

mercury, hydrogen chloride, and 

hydrogen fluoride in tables 2 and 3 to 

this subpart. 

(2) All applicable operating limits in 

§ 63.9590(b)(5) through (8), established 

in accordance with § 63.9622(g) through 

(i), for each control device used to 

comply with the mercury, hydrogen 

chloride, and hydrogen fluoride 

emission limits. 

(3) All applicable compliance 

requirements in §§ 63.9600, 63.9610, 

63.9623, 63.9625, and 63.9637(a). 

(4) The applicable performance 

testing or continuous emissions 

monitoring system (CEMS) requirements 

for mercury in §§ 63.9620(k), 

63.9621(d), and 63.9630. 

(5) All applicable performance testing 

requirements in §§ 63.9620(l), 

63.9621(d), and 63.9630. 

(6) The requirements to install and 

maintain monitoring equipment in 

§ 63.6332(g) through (i) and the 

monitoring requirements in §§ 63.9631, 

63.9633, and 63.9634 for each control 

device used to comply with the 

mercury, hydrogen chloride and 

hydrogen fluoride emission limits. 

(7) The notification, reporting and 

recordkeeping requirements in 

§§ 63.9640, 63.9641, 63.9642, and 

63.9643 applicable to the mercury, 

hydrogen chloride, and hydrogen 

fluoride emission standards. 

■ 4. Section 63.9590 is revised and 

republished to read as follows: 

§ 63.9590 What emission limitations and 

operating limits must I meet? 

(a) You must meet each emission limit 

in tables 1 through 3 to this subpart that 

applies to you by the applicable 

compliance date specified in § 63.9583. 

(b) You must meet each applicable 

operating limit for control devices in 

paragraphs (b)(1) through (8) of this 

section that applies to you by the 

applicable compliance date specified in 

§ 63.9583. You are not required to 

establish and comply with operating 

limits for control devices used to reduce 

mercury emissions when you are using 

a CEMS to monitor and demonstrate 

compliance with the mercury emission 

limit in table 2 to this subpart. 

(1) Except as provided in paragraph 

(b)(2) of this section, for each wet 

scrubber applied to meet any particulate 

matter emission limit in table 1 to this 

subpart, you must maintain the daily 

average pressure drop and daily average 

scrubber water flow rate at or above the 

minimum levels established in 

§ 63.9622. 

(2) On or before January 28, 2022, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, for each 

dynamic wet scrubber applied to meet 

any particulate matter emission limit in 

table 1 to this subpart, you must 

maintain the daily average scrubber 

water flow rate and either the daily 

average fan amperage (a surrogate for 

fan speed as revolutions per minute) or 

the daily average pressure drop at or 

above the minimum levels established 

during the initial performance test. After 

January 28, 2022, for affected sources 

that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, for each dynamic 

wet scrubber applied to meet any 

particulate matter emission limit in 

table 1 to this subpart, you must 

maintain the daily average scrubber 

water flow rate and the daily average fan 

amperage (a surrogate for fan speed as 

revolutions per minute) at or above the 

minimum levels established in 

§ 63.9622. 

(3) For each dry electrostatic 

precipitator (ESP) applied to meet any 

particulate matter emission limit in 

Table 1 to this subpart, you must meet 

the operating limits in paragraph 

(b)(3)(i) or (ii) of this section. 

(i) Maintain the 6-minute average 

opacity of emissions exiting the control 

device stack at or below the level 

established during the initial 

performance test. 

(ii) Maintain the daily average 

secondary voltage and daily average 

secondary current for each field at or 

above the minimum levels established 

during the initial performance test. 

(4) For each wet ESP applied to meet 

any particulate matter emission limit in 

table 1 to this subpart, you must meet 

the operating limits in paragraphs 

(b)(4)(i) through (iii) of this section. 

(i) Maintain the daily average 

secondary voltage for each field at or 

above the minimum levels established 

during the initial performance test. 

(ii) Maintain the daily average stack 

outlet temperature at or below the 

maximum levels established during the 

initial performance test. 

(iii) Maintain the daily average water 

flow rate at or above the minimum 

levels established during the initial 

performance test. 

(5) For each wet scrubber and wet ESP 

used to meet the hydrogen chloride and 

hydrogen fluoride emission limits in 

table 3 to this subpart, you must 

maintain the daily average scrubber 

water flow rate and pH greater than or 

equal to the operating limits established 

for these parameters established in 

§ 63.9622. 

(6) For each activated carbon injection 

(ACI) system used to meet the mercury 

emission limit in table 2 to this subpart, 

you must maintain the daily average 

activated carbon injection rate greater 

than or equal to the average activated 

carbon injection rate established during 

the most recent performance test 

demonstrating compliance with the 

applicable emission limit. In addition, 

you must maintain the daily average 

carrier gas flow rate greater than or 

equal to the average carrier gas flow rate 

established during the most recent 

performance test demonstrating 

compliance with the applicable 

emission limit. 

(7) For each dry sorbent injection 

(DSI) system used to meet the hydrogen 

chloride and hydrogen fluoride 

emission limits in table 3 to this 

subpart, you must maintain the daily 

average dry sorbent injection rate greater 

than or equal to the average dry sorbent 

injection rate established during the 

most recent performance test. 

demonstrating compliance with the 

applicable emission limit. In addition, 

you must maintain the daily average 

carrier gas flow rate greater than or 

equal to the average carrier gas flow rate 

established during the most recent 

performance test demonstrating 

compliance with the applicable 

emission limit. 

(8) If you use any air pollution control 

device other than a baghouse, wet 

scrubber, dynamic scrubber, dry ESP, 

wet ESP, ACI, or DSI, you must submit 

a site-specific monitoring plan in 

accordance with § 63.9631(f). 

(c) You may petition the 

Administrator for approval of 

alternatives to the monitoring 

requirements in paragraphs (b)(1) 

through (7) of this section as allowed 

under § 63.8(f) and as defined in § 63.90. 

■ 5. Section 63.9600 is amended by 

revising paragraph (b) introductory text 

to read as follows: 


ddrumheller on DSK120RN23PROD with RULES4
16426 Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 

§ 63.9600 What are my operation and 

maintenance requirements? 

* * * * * 

(b) You must prepare, and at all times, 

operate according to, a written operation 

and maintenance plan for each control 

device applied to meet any particulate 

matter emission limit in table 1 to this 

subpart, mercury emission limit in table 

2 to this subpart, hydrogen chloride and 

hydrogen fluoride emission limit in 

table 3 to this subpart, and to meet the 

requirement of each indurating furnace 

subject to good combustion practices 

(GCP). Each site-specific operation and 

maintenance plan must be submitted to 

the Administrator on or before the 

compliance date that is specified in 

§ 63.9583 for your affected source. The 

plan you submit must explain why the 

chosen practices (i.e., quantified 

objectives) are effective in performing 

corrective actions or GCP in minimizing 

the formation of formaldehyde (and 

other products of incomplete 

combustion). The Administrator will 

review the adequacy of the site-specific 

practices and objectives you will follow 

and the records you will keep to 

demonstrate compliance with your Plan. 

If the Administrator determines that any 

portion of your operation and 

maintenance plan is not adequate, we 

can reject those portions of the plan, 

and request that you provide additional 

information addressing the relevant 

issues. In the interim of this process, 

you will continue to follow your current 

site-specific practices and objectives, as 

submitted, until your revisions are 

accepted as adequate by the 

Administrator. You must maintain a 

current copy of the operation and 

maintenance plan onsite, and it must be 

available for inspection upon request. 

You must keep the plan for the life of 

the affected source or until the affected 

source is no longer subject to the 

requirements of this subpart. Each 

operation and maintenance plan must 

address the elements in paragraphs 

(b)(1) through (4) of this section. 

* * * * * 

■ 6. Section 63.9610 is amended by 

revising paragraph (a) introductory text 

and adding paragraph (d) to read as 

follows: 

§ 63.9610 What are my general 

requirements for complying with this 

subpart? 

(a) On or before January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, you must be 

in compliance with the requirements in 

paragraphs (a)(1) through (6) of this 

section at all times, except during 

periods of startup, shutdown, and 

malfunction. After January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, and after 

July 28, 2020, for affected sources that 

commenced construction or 

reconstruction after September 25, 2019, 

you must be in compliance with the 

emission limitations, standards, and 

operation and maintenance 

requirements for the particulate matter 

emission standards in this subpart at all 

times. 

* * * * * 

(d) On and after the applicable 

compliance date specified in 

§ 63.9583(f), you must be in compliance 

with all applicable emission limitations 

for mercury, hydrogen chloride and 

hydrogen fluoride in tables 2 and 3 to 

this subpart and with the requirements 

in paragraphs (d)(1) through (6) of this 

section at all times. 

(1) All applicable operating limits in 

§ 63.9590(b)(5) through (8). 

(2) All applicable operation and 

maintenance requirements in § 63.9600 

for control devices and monitoring 

equipment used to comply with the 

emissions limits. 

(3) The requirements in § 63.9631(j), if 

you use emissions averaging to 

demonstrate compliance with the 

mercury standards. 

(4) The requirements in § 63.9631(k), 

if you use continuous emissions 

monitoring system(s) (CEMS) to 

demonstrate compliance with the 

mercury standards. 

(5) The requirements in § 63.9634(n), 

if you elect to adjust the activated 

carbon injection rate based on the 

taconite pellet production rate. 

(6) The notification, reporting and 

recordkeeping requirements in 

§§ 63.9640 through 63.9643. 

■ 7. Section 63.9620 is amended by: 

■ a. Revising paragraphs (b)(2) and 

(f)(2); and 

■ b. Adding paragraphs (k) and (l). 

The revisions and addition read as 

follows: 

§ 63.9620 On which units and by what date 

must I conduct performance tests or other 

initial compliance demonstrations? 

* * * * * 

(b) * * * 

(2) Initial performance tests must be 

completed no later than 180 calendar 

days after the compliance date specified 

in § 63.9583. Performance tests 

conducted between October 30, 2003, 

and no later than 180 days after the 

corresponding compliance date can be 

used for initial compliance 

demonstration, provided the tests meet 

the initial performance testing 

requirements of this subpart. For an 

indurating furnace with multiple stacks, 

the performance tests for all stacks must 

be completed within 7 calendar days of 

commencement of the performance 

tests, to the extent practicable, and the 

indurating furnace and associated 

control device (where applicable) 

operating characteristics must remain 

representative and consistent for the 

duration of the stack tests. If you 

determine that the performance tests 

cannot be completed within 7 calendar 

days, the Administrator must be notified 

within 24 hours of making that 

determination. 

* * * * * 

(f) * * * 

(2) All emission units within a group 

must also have the same type of air 

pollution control device (e.g., wet 

scrubbers, dynamic wet scrubbers, 

rotoclones, multiclones, wet and dry 

ESP, and baghouses). You cannot group 

emission units with different air 

pollution control device types together 

for the purposes of this section. 

* * * * * 

(k) For each indurating furnace, you 

must demonstrate initial compliance 

with the mercury emission limits in 

table 2 to this subpart in accordance 

with the procedures specified in either 

paragraph (k)(1) or (2) of this section. 

(1) Complete an initial performance 

test on all stacks associated with each 

indurating furnace no later than 180 

calendar days after the compliance date 

specified in § 63.9583(f). Performance 

tests conducted between March 6, 2024 

and 180 days after the corresponding 

compliance date can be used for initial 

compliance demonstration, provided 

the tests meet the initial performance 

testing requirements of this subpart. For 

an indurating furnace with multiple 

stacks, the performance tests for all 

stacks must be completed within 7 

calendar days of commencement of the 

performance tests, to the extent 

practicable, and the indurating furnace 

and associated control device (where 

applicable) operating characteristics 

must remain representative and 

consistent for the duration of the stack 

tests. If you determine that the 

performance tests cannot be completed 

within 7 calendar days, the 

Administrator must be notified within 

24 hours of making that determination. 

(2) You may use a 30-day rolling 

average of the 1-hour arithmetic average 

CEMS data. You must conduct a 

performance evaluation of each CEMS 

within 180 days of installation of the 

monitoring system. The initial 

performance evaluation must be 

conducted prior to collecting CEMS data 


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Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16427 

that will be used for the initial 

compliance demonstration. 

(l) For each indurating furnace, you 

must demonstrate initial compliance 

with the emission limits in table 3 to 

this subpart by conducting initial 

performance tests for hydrogen chloride 

and hydrogen fluoride on all stacks 

associated with each indurating furnace. 

Initial performance tests must be 

completed no later than 180 calendar 

days after the compliance date specified 

in § 63.9583(f). Performance tests 

conducted between March 6, 2024 and 

180 days after the corresponding 

compliance date can be used for initial 

compliance demonstration, provided 

the tests meet the initial performance 

testing requirements of this subpart. For 

an indurating furnace with multiple 

stacks, the performance tests for all 

stacks must be completed within 7 

calendar days of commencement of the 

performance tests, to the extent 

practicable, and the indurating furnace 

and associated control device (where 

applicable) operating characteristics 

must remain representative and 

consistent for the duration of the stack 

tests. If you determine that the 

performance tests cannot be conducted 

within 7 calendar days, the 

Administrator must be notified within 

24 hours of making that determination. 

■ 8. Section 63.9621 is amended by: 

■ a. Revising the section heading; 

■ b. Revising paragraphs (a) and (c) 

introductory text; and 

■ c. Adding paragraphs (d) and (e). 

The revisions and additions read as 

follows: 

§ 63.9621 What test methods and other 

procedures must I use to demonstrate 

initial compliance with the emission limits? 

(a) On or before January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, you must 

conduct each performance test that 

applies to your affected source 

according to the requirements in 

§ 63.7(e)(1) and paragraphs (b) and (c) of 

this section. After January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, and after 

July 28, 2020, or upon start-up, which 

ever date is later, for affected sources 

that commenced construction or 

reconstruction after September 25, 2019, 

you must conduct each performance test 

that applies to your affected source, 

including the initial performance tests 

for mercury required in § 63.9620(k)(1) 

and the initial performance tests for 

hydrogen chloride and hydrogen 

fluoride required in § 63.9620(l), under 

normal operating conditions of the 

affected source. The owner or operator 

may not conduct performance tests 

during periods of malfunction. The 

owner or operator must record the 

process information that is necessary to 

document operating conditions during 

the test and include in such record an 

explanation to support that such 

conditions represent normal operation. 

Upon request, the owner or operator 

shall make available to the 

Administrator such records as may be 

necessary to determine the conditions of 

performance tests. You must also 

conduct each performance test that 

applies to your affected source 

according to the requirements in 

paragraphs (b) and (c) of this section. 

* * * * * 

(c) For each ore dryer affected source 

and each indurating furnace affected 

source, you must determine compliance 

with the applicable emission limit for 

particulate matter in table 1 to this 

subpart by following the test methods 

and procedures in paragraphs (c)(1) 

through (2) of this section. 

* * * * * 

(d) For each indurating furnace 

subject to the initial performance testing 

under § 63.9620(k)(1) or (l), you must 

determine compliance with the 

applicable emission limits for mercury, 

hydrogen chloride and hydrogen 

fluoride in tables 2 and 3 to this subpart 

by following the test methods and 

procedures in paragraphs (d)(1) through 

(9) of this section. You are not required 

to complete the initial performance test 

for mercury emissions when you are 

using a CEMS in accordance with 

paragraph (e) of this section. 

(1) The furnace must be operated at or 

above 90 percent of capacity throughout 

the duration of the performance testing. 

If testing cannot be performed at or 

above 90 percent of capacity, you must 

provide an explanation for the lower 

production rate in your performance test 

plan. The lower production rate must be 

approved by the Administrator prior to 

beginning performance testing. For 

indurating furnaces that comply with 

the mercury emissions limit in table 2 

to this subpart by adjusting the activated 

carbon injection rate based on the 

taconite pellet production rate, you 

must complete the performance testing 

for mercury in accordance with the 

provisions in § 63.9634(n). 

(2) Use the methods specified in 

paragraphs (c)(1)(i) through (iv) of this 

section to select sampling port locations 

and the number of traverse points and 

to determine the volumetric flow rate, 

dry molecular weight, and moisture 

content of the stack gas. 

(3) Determine the concentration of 

mercury for each stack using Method 29 

or Method 30B in 40 CFR part 60, 

appendix A, or the voluntary consensus 

standard ASTM D6784–16 (incorporated 

by reference, see § 63.14). For Method 

29 and ASTM D6784–16, the sample 

volume must be at least 1.7 dry standard 

cubic meters (dscm) (60 dry standard 

cubic feet) per run. For Method 30B, 

each test run must be at least one hour 

in duration. 

(4) Determine the concentration of 

hydrogen chloride and hydrogen 

fluoride for each stack using Method 

26A in 40 CFR part 60, appendix A. 

Each test must consist of three separate 

runs. The minimum sample volume 

must be at least 2 dscm per run. 

(5) During each stack test run, 

determine the weight of taconite pellets 

produced and calculate the emissions 

rate of each pollutant in pounds of 

pollutant per long ton (lb/LT) of pellets 

produced for each test run. The weight 

of taconite pellets produced must be 

determined by measurement using 

weigh hoppers, belt weigh feeders, or 

weighed quantities in shipments, or 

calculated using the bulk density and 

volume measurements. If any 

measurement result for any pollutant is 

reported as below the method detection 

limit, use the method detection limit as 

the measured emissions level for that 

pollutant when calculating the emission 

rate. If the furnace has more than one 

stack, calculate the total emissions rate 

for each test run by summing the 

emissions across all stacks, as shown in 

Equation 4. 

Where: 

Ef,i = Emissions rate for test run ‘‘i’’ for all 

emission stacks on indurating furnace 

‘‘f’’, lb/LT of pellets produced, 

Cs = Emission rate for stack ‘‘s’’ measured 

during test run ‘‘i’’ on indurating furnace 

‘‘f’’, lb/dscf, 

Qs = Average volumetric flow rate of stack 

gas measured at stack ‘‘s’’ during test run 

‘‘i’’ on indurating furnace ‘‘f’’, dscf/hour; 

Pf = Pellets produced in indurating furnace 

‘‘f’’ during the stack test, LT; and 

n = Number of emissions stacks on furnace 

‘‘f’’. 

(6) Calculate the average emissions 

rate for each furnace using the three test 

runs, as show in Equation 5 of this 

section. 

Where: 


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16428 Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 

Ef = Average emission rate for indurating 

furnace ‘‘f’’, lb/LT of pellets produced, 

E1 = Emissions rate for run 1 for indurating 

furnace ‘‘f’’, lb/LT of pellets produced, 

E2 = Emissions rate for run 2 for indurating 

furnace ‘‘f’’, lb/LT of pellets produced, 

and 

E3 = Emissions rate for run 3 for indurating 

furnace ‘‘f’’, lb/LT of pellets produced. 

(7) For each indurating furnace 

constructed or reconstructed on or after 

May 15, 2023, determine compliance 

with the applicable mercury emission 

limit in table 2 to this subpart by 

calculating the average emissions rate 

from the three test runs performed on 

the furnace using Equations 4 and 5 of 

this section. 

(8) For each indurating furnace 

constructed or reconstructed before May 

15, 2023, you must determine 

compliance with the applicable mercury 

emission limit in accordance with the 

procedures specified in either paragraph 

(d)(8)(i) or (ii) of this section. 

(i) Determine compliance with the 

mercury limit for individual furnaces in 

table 2 to this subpart by calculating the 

average mercury emissions rate for each 

affected indurating furnace using 

Equations 4 and 5 of this section, or 

(ii) Determine compliance with the 

mercury limit for groups of indurating 

furnaces in table 2 to this subpart in 

accordance with the method in 

§ 63.9623(d). 

(9) Determine compliance with the 

applicable hydrogen chloride and 

hydrogen fluoride emission limits in 

table 3 to this subpart by calculating the 

average emissions rate for each 

indurating furnace for the three test runs 

performed on the furnace using 

Equations 4 and 5 of this section. 

(e) For each indurating furnace using 

mercury CEMS to demonstrate 

compliance with the applicable 

emission limits for mercury, you must 

determine compliance with the 

applicable mercury limit in table 2 to 

this subpart by using a 30-day rolling 

average of the 1-hour arithmetic average 

CEMS data, including CEMS data 

during startup and shutdown as defined 

in this subpart. The mercury CEMS 

must be installed, calibrated, 

maintained, and operated as accordance 

with the requirements in § 63.9631(j). 

■ 9. Section 63.9622 is revised and 

republished to read as follows: 

§ 63.9622 What test methods and other 

procedures must I use to establish and 

demonstrate initial compliance with the 

operating limits? 

(a) For wet scrubbers subject to 

performance testing in § 63.9620 and 

operating limits for pressure drop and 

scrubber water flow rate in 

§ 63.9590(b)(1), you must establish sitespecific operating limits according to 

the procedures in paragraphs (a)(1) 

through (3) of this section. 

(1) Using the CPMS required in 

§ 63.9631(b), measure and record the 

pressure drop and scrubber water flow 

rate every 15 minutes during each run 

of the particulate matter performance 

test. 

(2) Calculate and record the average 

pressure drop and scrubber water flow 

rate for each individual test run. Your 

operating limits are established as the 

lowest average pressure drop and the 

lowest average scrubber water flow rate 

corresponding to any of the three test 

runs, except as specified in paragraph 

(g)(2) of this section. 

(3) If a rod-deck venturi scrubber is 

applied to an indurating furnace to meet 

any particulate matter emission limit in 

table 1 to this subpart, you may 

establish a lower average pressure drop 

operating limit by using historical 

average pressure drop data from a 

certified performance test completed on 

or after December 18, 2002 instead of 

using the average pressure drop value 

determined during the initial 

performance test, as specified in 

paragraph (a)(2) of this section. If 

historical average pressure drop data are 

used to establish an operating limit (i.e., 

using data from a certified performance 

test conducted prior to the promulgation 

date of the final rule), then the average 

particulate matter concentration 

corresponding to the historical 

performance test must be at or below the 

applicable indurating furnace emission 

limit, as listed in table 1 to this subpart. 

(b) On or before January 28, 2022, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, for dynamic 

wet scrubbers subject to performance 

testing in § 63.9620 and operating limits 

for scrubber water flow rate and either 

fan amperage or pressure drop in 

§ 63.9590(b)(2), you must establish sitespecific operating limits according to 

the procedures in paragraphs (b)(1) and 

(2) of this section. After January 28, 

2022, for affected sources that 

commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, for dynamic wet 

scrubbers subject to performance testing 

in § 63.9620 and operating limits for 

scrubber water flow rate and fan 

amperage in § 63.9590(b)(2), you must 

establish site-specific operating limits 

according to the procedures in 

paragraphs (b)(1) and (2) of this section. 

(1) On or before January 28, 2022, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, using the 

CPMS required in § 63.9631(b), measure 

and record the scrubber water flow rate 

and either the fan amperage or pressure 

drop every 15 minutes during each run 

of the particulate matter performance 

test. After January 28, 2022, for affected 

sources that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, using the CPMS 

required in § 63.9631(b), measure and 

record the scrubber water flow rate and 

the fan amperage every 15 minutes 

during each run of the particulate matter 

performance test. 

(2) On or before January 28, 2022, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, calculate 

and record the average scrubber water 

flow rate and either the average fan 

amperage or the average pressure drop 

for each individual test run. Your 

operating limits are established as the 

lowest average scrubber water flow rate 

and either the lowest average fan 

amperage or pressure drop value 

corresponding to any of the three test 

runs. After January 28, 2022, for affected 

sources that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, calculate and 

record the average scrubber water flow 

rate and the average fan amperage for 

each individual test run. Your operating 

limits are established as the lowest 

average scrubber water flow rate and the 

lowest average fan amperage value 

corresponding to any of the three test 

runs, except as specified in paragraph 

(g)(2) of this section. 

(c) For a dry ESP subject to 

performance testing in § 63.9620 and 

operating limits in § 63.9590(b)(3), you 

must establish a site-specific operating 

limit according to the procedures in 

paragraphs (c)(1) or (2) of this section. 

(1) If the operating limit for your dry 

ESP is a 6-minute average opacity of 

emissions value, then you must follow 

the requirements in paragraphs (c)(1)(i) 

through (iii) of this section. 

(i) Using the continuous opacity 

monitoring system (COMS) required in 

§ 63.9631(d)(1), measure and record the 

opacity of emissions from each control 

device stack during the particulate 

matter performance test. 


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(ii) Compute and record the 6-minute 

opacity averages from 24 or more data 

points equally spaced over each 6- 

minute period (e.g., at 15-second 

intervals) during the test runs. 

(iii) Using the opacity measurements 

from a performance test that meets the 

emission limit, determine the opacity 

value corresponding to the 99 percent 

upper confidence level of a normal 

distribution of the 6-minute opacity 

averages. 

(2) If the operating limit for your dry 

ESP is the daily average secondary 

voltage and daily average secondary 

current for each field, then you must 

follow the requirements in paragraphs 

(c)(2)(i) and (ii) of this section. 

(i) Using the CPMS required in 

§ 63.9631(d)(2), measure and record the 

secondary voltage and secondary 

current for each dry ESP field every 15 

minutes during each run of the 

particulate matter performance test. 

(ii) Calculate and record the average 

secondary voltage and secondary 

current for each dry ESP field for each 

individual test run. Your operating 

limits are established as the lowest 

average secondary voltage and 

secondary current value for each dry 

ESP field corresponding to any of the 

three test runs. 

(d) For a wet ESP subject to 

performance testing in § 63.9620 and 

operating limit in § 63.9590(b)(4), you 

must establish a site-specific operating 

limit according to the procedures in 

paragraphs (d)(1) and (2) of this section. 

(1) Using the CPMS required in 

§ 63.9631(e), measure and record the 

parametric values in paragraphs (d)(1)(i) 

through (iii) of this section for each wet 

ESP field every 15 minutes during each 

run of the particulate matter 

performance test. 

(i) Secondary voltage; 

(ii) Water flow rate; and 

(iii) Stack outlet temperature. 

(2) For each individual test run, 

calculate and record the average value 

for each operating parameter in 

paragraphs (d)(1)(i) through (iii) of this 

section for each wet ESP field. Your 

operating limits are established as the 

lowest average value for each operating 

parameter of secondary voltage and 

water flow rate corresponding to any of 

the three test runs, and the highest 

average value for each stack outlet 

temperature corresponding to any of the 

three test runs. 

(e) If you use an air pollution control 

device other than a wet scrubber, 

dynamic wet scrubber, dry ESP, wet 

ESP, or baghouse, and it is subject to 

performance testing in § 63.9620, you 

must submit a site-specific monitoring 

plan in accordance with § 63.9631(f). 

The site-specific monitoring plan must 

include the site-specific procedures for 

demonstrating initial and continuous 

compliance with the corresponding 

operating limits. 

(f) You may change the operating 

limits for any air pollution control 

device as long as you meet the 

requirements in paragraphs (f)(1) 

through (3) of this section. 

(1) Submit a written notification to 

the Administrator of your request to 

conduct a new performance test to 

revise the operating limit. 

(2) Conduct a performance test to 

demonstrate compliance with the 

applicable emission limitation in table 1 

to this subpart. 

(3) Establish revised operating limits 

according to the applicable procedures 

in paragraphs (a) through (e) of this 

section. 

(g) For wet scrubbers and wet ESPs 

subject to performance testing in 

§ 63.9620(l) and operating limits for 

scrubber water flow rate and pH in 

§ 63.9590(b)(5), you must establish sitespecific operating limits according to 

the procedures in paragraphs (g)(1) and 

(2) of this section. 

(1) Using the CPMS required in 

§ 63.9631(b), measure and record the 

scrubber water flow rate and pH of the 

scrubber water effluent every 15 

minutes during each run of the 

performance test for hydrogen chloride 

and hydrogen fluoride. 

(2) Calculate and record the average 

scrubber water flow rate and average pH 

of the scrubber water effluent for each 

individual test run. Your operating limit 

must be established as the average 

scrubber water flow rate and average pH 

of the scrubber water of the three test 

runs. If a higher average flow rate is 

measured during the most recent PM 

performance test, the operating limit for 

the daily average scrubber water flow 

rate is the average scrubber water flow 

rate measured during the most recent 

PM performance test. If a higher average 

flow rate is measured during the most 

recent HCl and HF performance test, the 

operating limit for the daily average 

scrubber water flow rate is the average 

scrubber water flow rate measured 

during the most recent HCl and HF 

performance test. 

(h) For ACI systems subject to 

performance testing in § 63.9620(k)(1) 

and operating limits for activated carbon 

sorbent injection rate and carrier gas 

flow rate in § 63.9590(b)(6), you must 

establish site-specific operating limits 

according to the procedures in 

paragraphs (h)(1) and (2) of this section. 

(1) Using the CPMS required in 

§ 63.9631(b), measure and record the 

activated carbon injection rate and 

carrier gas flow rate every 15 minutes 

during each run of the performance test 

for mercury. 

(2) Calculate and record the average 

activated carbon injection rate and 

carrier gas flow rate for each individual 

test run. Your operating limit must be 

established as the highest activated 

carbon injection rate and carrier gas 

flow rate of the three test runs. 

(i) For DSI systems subject to 

performance testing in § 63.9620(l) and 

operating limits for sorbent injection 

rate and carrier gas flow rate in 

§ 63.9590(b)(7), you must establish sitespecific operating limits according to 

the procedures in paragraphs (i)(1) and 

(2) of this section. 

(1) Using the CPMS required in 

§ 63.9631(b), measure and record the 

sorbent injection rate and carrier gas 

flow rate every 15 minutes during each 

run of the performance test for hydrogen 

chloride and hydrogen fluoride. 

(2) Calculate and record the average 

sorbent injection rate and carrier gas 

flow rate for each individual test run. 

Your operating limit must be 

established as the highest average 

sorbent injection rate and carrier gas 

flow rate of the three test runs. 

■ 10. Section 63.9623 is revised and 

republished to read as follows: 

§ 63.9623 How do I demonstrate initial 

compliance with the emission limitations 

that apply to me? 

(a) For each affected source subject to 

an emission limit in tables 1 through 3 

to this subpart, you must demonstrate 

initial compliance by meeting the 

emission limit requirements in 

paragraphs (a)(1) through (8) of this 

section by the compliance date specified 

in § 63.9583. 

(1) For ore crushing and handling, the 

flow-weighted mean concentration of 

particulate matter, determined 

according to the procedures in 

§§ 63.9620(a) and 63.9621(b), must not 

exceed the emission limits in table 1 to 

this subpart. 

(2) For indurating furnaces, the flowweighted mean concentration of 

particulate matter, determined 

according to the procedures in 

§§ 63.9620(b) and 63.9621(c), must not 

exceed the emission limits in table 1 to 

this subpart. 

(3) For finished pellet handling, the 

flow-weighted mean concentration of 

particulate matter, determined 

according to the procedures in 

§§ 63.9620(c) and 63.9621(b), must not 

exceed the emission limits in table 1 to 

this subpart. 

(4) For ore dryers, the flow-weighted 

mean concentration of particulate 

matter, determined according to the 


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procedures in §§ 63.9620(d) and 

63.9621(c), must not exceed the 

emission limits in table 1 to this 

subpart. 

(5) For indurating furnaces not using 

emissions averaging, the mercury 

emissions determined according to the 

procedures in §§ 63.9620(k)(1) or (2) and 

63.9621(d), must not exceed the 

applicable emission limit in table 2 to 

this subpart. 

(6) For indurating furnaces that 

comply with the mercury emissions 

limit using emissions averaging, the 

average mercury emissions determined 

according to the procedures in 

§§ 63.9620(k)(1) or (2), 63.9621(d) and 

63.9634(m), must not exceed the 

applicable emission limit in table 2 to 

this subpart. 

(7) For indurating furnaces that 

comply with the mercury emissions 

limit by adjusting the activated carbon 

injection rate based on the taconite 

pellet production rate, the mercury 

emissions determined according to the 

procedures in §§ 63.9620(k)(1) or (2), 

63.9621(d) or (e), and 63.9634(n), must 

not exceed the applicable emission limit 

in table 2 to this subpart. 

(8) For indurating furnaces, the 

hydrogen chloride and hydrogen 

fluoride emissions determined 

according to the procedures in 

§§ 63.9620(l) and 63.9621(d), must not 

exceed the applicable emission limit in 

table 3 to this subpart. 

(b) For each affected source subject to 

an emission limit in table 1 to this 

subpart, you must demonstrate initial 

compliance by meeting the operating 

limit requirements in paragraphs (b)(1) 

through (5) of this section. 

(1) For each wet scrubber subject to 

performance testing in § 63.9620 and 

operating limits for pressure drop and 

scrubber water flow rate in 

§ 63.9590(b)(1), you have established 

appropriate site-specific operating limits 

and have a record of the pressure drop 

and scrubber water flow rate measured 

during the performance test in 

accordance with § 63.9622(a). 

(2) On or before January 28, 2022, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, for each 

dynamic wet scrubber subject to 

performance testing in § 63.9620 and 

operating limits for scrubber water flow 

rate and either fan amperage or pressure 

drop in § 63.9590(b)(2), you have 

established appropriate site-specific 

operating limits and have a record of the 

scrubber water flow rate and either the 

fan amperage or pressure drop value, 

measured during the performance test in 

accordance with § 63.9622(b). After 

January 28, 2022, for affected sources 

that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, for each dynamic 

wet scrubber subject to performance 

testing in § 63.9620 and operating limits 

for scrubber water flow rate and fan 

amperage in § 63.9590(b)(2), you have 

established appropriate site-specific 

operating limits and have a record of the 

scrubber water flow rate and the fan 

amperage value, measured during the 

performance test in accordance with 

§ 63.9622(b). 

(3) For each dry ESP subject to 

performance testing in § 63.9620 and 

one of the operating limits in 

§ 63.9590(b)(3), you must meet the 

requirements in paragraph (b)(3)(i) or 

(ii) of this section. 

(i) If you are subject to the operating 

limit for opacity in § 63.9590(b)(3)(i), 

you have established appropriate sitespecific operating limits and have a 

record of the opacity measured during 

the performance test in accordance with 

§ 63.9622(c)(1). 

(ii) If you are subject to the operating 

limit for secondary voltage and 

secondary current in § 63.9590(b)(3)(ii), 

you have established appropriate sitespecific operating limits and have a 

record of the secondary voltage and 

secondary current measured during the 

performance test in accordance with 

§ 63.9622(c)(2). 

(4) For each wet ESP subject to 

performance testing in § 63.9620 and 

operating limits for secondary voltage, 

water flow rate, and stack outlet 

temperature in § 63.9590(b)(4), you have 

established appropriate site-specific 

operating limits and have a record of the 

secondary voltage, water flow rate, and 

stack outlet temperature measured 

during the performance test in 

accordance with § 63.9622(d). 

(5) For other air pollution control 

devices subject to performance testing 

in § 63.9620 and operating limits in 

accordance with § 63.9590(b)(8), you 

have submitted a site-specific 

monitoring plan in accordance with 

§ 63.9631(f) and have a record of the 

site-specific operating limits as 

measured during the performance test in 

accordance with § 63.9622(e). 

(c) Except as specified in paragraph 

(e) of this section, you must demonstrate 

initial compliance with the emission 

limits in tables 2 and 3 to this subpart, 

by meeting the operating limit 

requirements in paragraphs (c)(1) 

through (3) of this section. 

(1) For each wet scrubber and wet ESP 

subject to performance testing in 

§ 63.9620(k) and operating limits for 

scrubber water flow rate and pH in 

§ 63.9590(b)(5), you have established 

appropriate site-specific operating limits 

and have a record of the scrubber water 

flow rate and pH measured during the 

performance test in accordance with 

§ 63.9622(g). 

(2) For each ACI subject to 

performance testing in § 63.9620(k) and 

operating limits for activated carbon 

injection rate and carrier gas flow rate 

in § 63.9590(b)(6), you have established 

appropriate site-specific operating limits 

and have a record of the activated 

carbon injection rate and carrier gas 

flow rate measured during the 

performance test in accordance with 

§ 63.9622(i).(3) For each DSI subject to 

performance testing in § 63.9620(k) and 

operating limits for sorbent injection 

rate and carrier gas flow rate in 

§ 63.9590(b)(7), you have established 

appropriate site-specific operating limit 

and have a record of the sorbent 

injection rate and carrier gas flow rate 

measured during the performance test in 

accordance with § 63.9622(h). 

(d) If you elect to comply with the 

mercury limit in table 2 to this subpart 

using emissions averaging for indurating 

furnaces constructed or reconstructed 

before May 15, 2023, you must comply 

with the requirements in paragraphs 

(d)(1) through (4) of this section. 

(1) Before submitting the 

implementation plan required in 

paragraph (d)(3) of this section, you 

must complete the mercury stack testing 

required in § 63.9620(k)(1) or install, 

calibrate, and operate a mercury CEMS 

pursuant to § 63.9620(k)(2) and 

paragraph (e) of this section for all 

indurating furnaces you wish to include 

in the mercury emission average. 

(2) You must develop and submit to 

the applicable regulatory authority for 

review and approval, an 

implementation plan for mercury 

emission averaging no later than 180 

days before the date you intend to 

demonstrate compliance using the 

emission averaging option. You must 

include the information contained in 

paragraphs (d)(2)(i) through (iii) of this 

section in your implementation plan. 

(i) Identification of all indurating 

furnaces in the averaging group, 

including the typical taconite pellet 

production rate, control technology 

installed, and types of fuel(s) that will 

be burned. 

(ii) The mercury emission rate for 

each furnace for each of the fuels 

identified in paragraph (d)(2)(i) of this 

section. 

(iii) The date on which you are 

requesting emission averaging to 

commence. 


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(3) The regulatory authority shall 

review and approve or disapprove the 

plan according to the following criteria: 

(i) Whether the content of the plan 

includes all the information specified in 

paragraph (d)(2) of this section, and 

(ii) Whether the plan presents 

sufficient information to determine that 

compliance will be achieved and 

maintained. 

(4) The applicable regulatory 

authority shall not approve an emission 

averaging implementation plan 

containing any of the following 

provisions: 

(i) Averaging that includes indurating 

furnaces constructed or reconstructed 

on or after May 15, 2023, or 

(ii) Averaging between indurating 

furnaces located at different facilities. 

(e) If you elect to demonstrate 

compliance with the mercury limit in 

table 2 to this subpart using a mercury 

CEMS, you must calculate the 30-day 

rolling average of 1-hour arithmetic 

average emission concentrations, 

including CEMS data during startup and 

shutdown, calculated using equation 

19–19 in section 12.4.1 of EPA 

Reference Method 19 at appendix A–7 

of 40 CFR part 60. The 1-hour arithmetic 

averages for CEMS must be calculated 

using the data points required under 

§ 63.8(c)(4)(ii). 

(f) For each emission limitation and 

operating limit that applies to you, you 

must submit a notification of 

compliance status according to 

§ 63.9640(e) 

■ 11. Section 63.9630 is amended by 

revising paragraphs (b) and (e)(2) to read 

as follows: 

§ 63.9630 When must I conduct 

subsequent performance tests? 

* * * * * 

(b) You must conduct subsequent 

performance tests on all stacks 

associated with indurating furnaces to 

demonstrate continued compliance with 

the indurating furnace emission limits 

in tables 1 through 3 to this subpart 

according to the schedule developed by 

your permitting authority and shown in 

your title V permit, but no less frequent 

than twice per 5-year permit term. If a 

title V permit has not been issued, you 

must submit a testing plan and 

schedule, containing the information 

specified in paragraph (e) of this 

section, to the permitting authority for 

approval. For an indurating furnace 

with multiple stacks, the performance 

tests for all stacks must be conducted 

within 7 calendar days of 

commencement of the performance 

tests, to the extent practicable, and the 

indurating furnace and associated 

control device (where applicable) 

operating characteristics must remain 

representative and consistent for the 

duration of the stack tests. If you 

determine that the performance tests 

cannot be completed within 7 calendar 

days, the Administrator must be notified 

within 24 hours of making that 

determination. Performance testing for 

mercury is not required for furnaces 

using CEMS to demonstrate compliance 

with the mercury emission limits in 

table 2 to this subpart. 

* * * * * 

(e) * * * 

(2) A schedule indicating when you 

will conduct subsequent performance 

tests for particulate matter, mercury, 

hydrogen chloride and hydrogen 

fluoride for each of the emission units. 

■ 12. Section 63.9631 is amended by: 

■ a. Revising and republishing 

paragraphs (d) through (f); and 

■ b. Adding paragraphs (g) through (k). 

The revisions and additions read as 

follows: 

§ 63.9631 What are my monitoring 

requirements? 

* * * * * 

(d) For each dry ESP subject to the 

operating limits in § 63.9590(b)(3), you 

must follow the monitoring 

requirements in paragraph (d)(1) or (2) 

of this section. 

(1) If the operating limit you choose 

to monitor is the 6-minute average 

opacity of emissions in accordance with 

§ 63.9590(b)(3)(i), you must install, 

operate, and maintain a COMS 

according to the requirements in 

§ 63.9632(f) and monitor the 6-minute 

average opacity of emissions exiting 

each control device stack according to 

the requirements in § 63.9633. 

(2) If the operating limit you choose 

to monitor is average secondary voltage 

and average secondary current for each 

dry ESP field in accordance with 

§ 63.9590(b)(3)(ii), you must install, 

operate, and maintain a CPMS 

according to the requirements in 

§ 63.9632(b) through (e) and monitor the 

daily average secondary voltage and 

daily average secondary current 

according to the requirements in 

§ 63.9633. 

(e) For each wet ESP subject to the 

operating limits in § 63.9590(b)(4), you 

must install, operate, and maintain a 

CPMS according to the requirements in 

§ 63.9632(b) through (e) and monitor the 

daily average secondary voltage, daily 

average stack outlet temperature, and 

daily average water flow rate according 

to the requirements in § 63.9633. 

(f) For each wet scrubber and wet ESP 

subject to the operating limits in 

§ 63.9590(b)(5), you must install, 

operate, and maintain a CPMS 

according to the requirements in 

§ 63.9632(g) and monitor the daily 

average scrubber water flow rate and pH 

of the scrubber water effluent. 

(g) For each ACI system subject to the 

operating limits in § 63.9590(b)(6), you 

must install, operate, and maintain a 

CPMS according to the requirements in 

§ 63.9632(h) and (i) and monitor the 

daily average activated carbon injection 

rate and carrier gas flow rate. 

(h) For each DSI system subject to the 

operating limits in § 63.9590(b)(7), you 

must install, operate, and maintain a 

CPMS according to the requirements in 

§ 63.9632(h) and (i) and monitor the 

daily average sorbent injection rate and 

carrier gas flow rate. 

(i) If you use any air pollution control 

device other than a baghouse, wet 

scrubber, dry ESP, wet ESP, DSI, or ACI, 

you must submit a site-specific 

monitoring plan that includes the 

information in paragraphs (i)(1) through 

(4) of this section. The monitoring plan 

is subject to approval by the 

Administrator. You must maintain a 

current copy of the monitoring plan 

onsite, and it must be available for 

inspection upon request. You must keep 

the plan for the life of the affected 

source or until the affected source is no 

longer subject to the requirements of 

this subpart. 

(1) A description of the device. 

(2) Test results collected in 

accordance with § 63.9621 verifying the 

performance of the device for reducing 

emissions of particulate matter, 

mercury, hydrogen chloride, and 

hydrogen fluoride to the atmosphere to 

the levels required by this subpart. 

(3) A copy of the operation and 

maintenance plan required in 

§ 63.9600(b). 

(4) Appropriate operating parameters 

that will be monitored to maintain 

continuous compliance with the 

applicable emission limitation(s). 

(j) If you elect to comply with the 

mercury limit in table 2 to this subpart 

using emissions averaging in accordance 

with an implementation plan approved 

under the provisions in § 63.9623(d) or 

you elect to adjust the activated carbon 

injection rate based on the taconite 

pellet production rate in accordance 

with the procedures in § 63.9634(n), you 

must determine and record the mass of 

taconite pellets produced each month 

by each furnace included in the 

emissions averaging group. The weight 

of taconite pellets produced must be 

determined by measurement using 

weigh hoppers, belt weigh feeders, or 

weighed quantities in shipments, or 

calculated using the bulk density and 

volume measurements. 


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(k) If you elect to demonstrate 

compliance with the mercury emissions 

limits in table 2 to this subpart using a 

CEMS to measure mercury emissions, 

you must comply with the requirements 

in (k)(1) through (5). 

(1) Notify the Administrator one 

month before starting use of the CEMS 

and notify the Administrator 180-days 

before ceasing use of the CEMS. 

(2) Each CEMS must be installed, 

certified, calibrated, and maintained 

according to the requirements of 

performance specifications 6 and 12A of 

40 CFR part 60, appendix B, and quality 

assurance procedure 6 of 40 CFR part 

60, appendix F. 

(3) Operate the mercury CEMS in 

accordance with performance 

specification 12A of 40 CFR part 60, 

appendix B. The duration of the 

performance test must be 30 operating 

days. For each day in which the unit 

operates, you must obtain hourly 

mercury concentration data, and stack 

gas volumetric flow rate data. 

(4) You must complete the initial 

performance evaluation of the CEMS 

within 180 days after notifying the 

Administrator and before starting to use 

the CEMS data in lieu of performance 

testing and monitoring operating 

parameters to demonstrate compliance. 

(5) Collect CEMS hourly averages for 

all operating hours on a 30-day rolling 

average basis. The one-hour arithmetic 

averages, expressed in units of lb/LT, 

must be used to calculate 30-day rolling 

average emissions to determine 

compliance with the applicable 

emission limit in table 2 to this subpart. 

■ 13. Section 63.9632 is amended by: 

■ a. Revising paragraphs (f) introductory 

text and (f)(2); and 

■ b. Adding paragraphs (g) through (i). 

The revisions and additions read as 

follows: 

§ 63.9632 What are the installation, 

operation, and maintenance requirements 

for my monitoring equipment? 

* * * * * 

(f) For each dry ESP subject to the 

opacity operating limit in 

§ 63.9590(b)(3)(i), you must install, 

operate, and maintain each COMS 

according to the requirements in 

paragraphs (f)(1) through (4) of this 

section. 

* * * * * 

(2) On or before January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, you must 

develop and implement a quality 

control program for operating and 

maintaining each COMS according to 

§ 63.8. At a minimum, the quality 

control program must include a daily 

calibration drift assessment, quarterly 

performance audit, and annual zero 

alignment of each COMS. After January 

25, 2021, for affected sources that 

commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, you must develop 

and implement a quality control 

program for operating and maintaining 

each COMS according to § 63.8(a) and 

(b), (c)(1)(ii), (c)(2) through (8), (d)(1) 

and (2), and (e) through (g) and 

Procedure 3 in appendix F to 40 CFR 

part 60. At a minimum, the quality 

control program must include a daily 

calibration drift assessment, quarterly 

performance audit, and annual zero 

alignment of each COMS. 

* * * * * 

(g) For each pH measurement device, 

in addition to the requirements in 

paragraphs (b) through (e) of this 

section, you must meet the requirements 

in paragraphs (g)(1) through (4) of this 

section. 

(1) The minimum accuracy of the pH 

measurement device must be ±0.2 pH 

units. 

(2) Locate the pH sensor in a position 

that provides a representative 

measurement of scrubber effluent pH. 

(3) Ensure the sample is properly 

mixed and representative of the fluid to 

be measured. 

(4) Check the pH meter’s calibration 

on at least two points every 8 hours of 

process operation. 

(h) For each mass flow rate monitor 

used for measuring the sorbent or 

activated carbon injection rate, in 

addition to the requirements in 

paragraphs (b) through (e) of this 

section, you must meet the requirements 

of (h)(1) through (4) of this section. 

(1) The minimum accuracy of the 

mass flow rate monitor must be ±5 

percent over the normal range of flow 

measured. 

(2) Locate the device in a position(s) 

that provides a representative 

measurement of the total sorbent 

injection rate. 

(3) Install and calibrate the device in 

accordance with manufacturer’s 

procedures and specifications. 

(4) At least annually, conduct a 

performance evaluation of the injection 

rate monitoring system in accordance 

with your monitoring plan. 

(i) For each carrier gas flow rate 

monitor, in addition to the requirements 

in paragraphs (b) through (e) of this 

section, you must meet the requirements 

of (i)(1) through (4) of this section. 

(1) The minimum accuracy of the gas 

flow rate monitor must be ±5 percent 

over the normal range of flow measured 

or 280 liters per minute (10 cubic feet 

per minute), whichever is greater. 

(2) Locate the device in a position(s) 

that provides a representative 

measurement of the carrier gas flow rate. 

(3) Install and calibrate the device in 

accordance with manufacturer’s 

procedures and specifications. 

(4) At least annually, conduct a 

performance evaluation of the carrier 

gas flow rate monitoring system in 

accordance with your monitoring plan. 

■ 14. Section 63.9634 is amended by 

revising paragraphs (a), (e)(4), (f)(4), (g) 

through (j) and adding paragraphs (k) 

through (n) to read as follows: 

§ 63.9634 How do I demonstrate 

continuous compliance with the emission 

limitations that apply to me? 

(a) For each affected source subject to 

an emission limit in table 1 to this 

subpart, you must demonstrate 

continuous compliance by meeting the 

requirements in paragraphs (b) through 

(h) of this section. 

* * * * * 

(e) * * * 

(4) If the daily average pressure drop 

or daily average scrubber water flow rate 

is below the operating limits established 

for a corresponding emission unit or 

group of similar emission units, you 

must then follow the corrective action 

procedures in paragraph (l) of this 

section. 

(f) * * * 

(4) On or before January 28, 2022, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, if the daily 

average scrubber water flow rate, daily 

average fan amperage, or daily average 

pressure drop is below the operating 

limits established for a corresponding 

emission unit or group of similar 

emission units, you must then follow 

the corrective action procedures in 

paragraph (l) of this section. After 

January 28, 2022, for affected sources 

that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, if the daily average 

scrubber water flow rate or daily average 

fan amperage, is below the operating 

limits established for a corresponding 

emission unit or group of similar 

emission units, you must then follow 

the corrective action procedures in 

paragraph (l) of this section. 

(g) For each dry ESP subject to 

operating limits in § 63.9590(b)(3), you 


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must demonstrate continuous 

compliance by completing the 

requirements of paragraph (g)(1) or (2) of 

this section. 

(1) If the operating limit for your dry 

ESP is a 6-minute average opacity of 

emissions value, then you must follow 

the requirements in paragraphs (g)(1)(i) 

through (iii) of this section. 

(i) Maintaining the 6-minute average 

opacity of emissions at or below the 

maximum level established during the 

initial or subsequent performance test. 

(ii) Operating and maintaining each 

COMS and reducing the COMS data 

according to § 63.9632(f). 

(iii) If the 6-minute average opacity of 

emissions is above the operating limits 

established for a corresponding 

emission unit, you must then follow the 

corrective action procedures in 

paragraph (l) of this section. 

(2) If the operating limit for your dry 

ESP is the daily average secondary 

voltage and daily average secondary 

current for each field, then you must 

follow the requirements in paragraphs 

(g)(2)(i) through (iv) of this section. 

(i) Maintaining the daily average 

secondary voltage or daily average 

secondary current for each field at or 

above the minimum levels established 

during the initial or subsequent 

performance test. 

(ii) Operating and maintaining each 

dry ESP CPMS according to § 63.9632(b) 

and recording all information needed to 

document conformance with these 

requirements. 

(iii) Collecting and reducing 

monitoring data for secondary voltage or 

secondary current for each field 

according to § 63.9632(c) and recording 

all information needed to document 

conformance with these requirements. 

(iv) If the daily average secondary 

voltage or daily average secondary 

current for each field is below the 

operating limits established for a 

corresponding emission unit, you must 

then follow the corrective action 

procedures in paragraph (l) of this 

section. 

(h) For each wet ESP subject to the 

operating limits for secondary voltage, 

stack outlet temperature, and water flow 

rate in § 63.9590(b)(4), you must 

demonstrate continuous compliance by 

completing the requirements of 

paragraphs (h)(1) through (4) of this 

section. 

(1) Maintaining the daily average 

secondary voltage and daily average 

scrubber water flow rate for each field 

at or above the minimum levels 

established during the initial or 

subsequent performance test. 

Maintaining the daily average stack 

outlet temperature at or below the 

maximum levels established during the 

initial or subsequent performance test. 

(2) Operating and maintaining each 

wet ESP CPMS according to § 63.9632(b) 

and recording all information needed to 

document conformance with these 

requirements. 

(3) Collecting and reducing 

monitoring data for secondary voltage, 

stack outlet temperature, and water flow 

rate according to § 63.9632(c) and 

recording all information needed to 

document conformance with these 

requirements. 

(4) If the daily average secondary 

voltage, stack outlet temperature, or 

water flow rate does not meet the 

operating limits established for a 

corresponding emission unit, you must 

then follow the corrective action 

procedures in paragraph (l) of this 

section. 

(i) For each affected indurating 

furnace subject to a hydrogen chloride 

and hydrogen fluoride emission limit in 

table 3 to this subpart, you must 

demonstrate continuous compliance by 

meeting the requirements in paragraphs 

(i)(1) and (2) of this section. 

(1) For each wet scrubber and wet ESP 

subject to the operating limits for 

scrubber water flow rate and pH in 

§ 63.9590(b)(5), you must demonstrate 

continuous compliance by completing 

the requirements of paragraphs (i)(1)(i) 

through (iv) of this section. 

(i) Maintaining the daily average 

scrubber water flow rate and daily 

average pH of the scrubber water 

effluent at or above the minimum level 

established during the most recent 

performance test. If a higher average 

flow rate is measured during the last PM 

performance test, the operating limit for 

daily average scrubber water flow rate is 

the highest average scrubber water flow 

rate measured during the last PM 

performance test. 

(ii) Operating and maintaining each of 

the CPMS used to measure scrubber 

water flow rate and pH according to 

§ 63.9632(g) and recording all 

information needed to document 

conformance with these requirements. 

(iii) Collecting and reducing 

monitoring data for scrubber water flow 

rate and pH according to § 63.9632(c) 

and recording all information needed to 

document conformance with these 

requirements. 

(iv) If the daily average scrubber water 

flow rate or daily average pH is below 

the operating limits established for 

control device, you must follow the 

corrective action procedures in 

paragraph (l) of this section. 

(2) For each DSI subject to the 

operating limits for sorbent injection 

rate and carrier gas flow rate in 

§ 63.9590(b)(7), you must demonstrate 

continuous compliance by completing 

the requirements of paragraphs (i)(2)(i) 

through (iv) of this section. 

(i) Maintain the daily average sorbent 

injection rate and carrier gas flow rate 

at or above the minimum level 

established during the most recent 

performance test. 

(ii) Operate and maintain each CPMS 

used to measure the sorbent injection 

rate according to § 63.9632(h) and the 

carrier gas flow rate according to 

§ 63.9632(i) and recording all 

information needed to document 

compliance with these requirements. 

(iii) Collect and reduce monitoring 

data for the sorbent injection rate and 

carrier gas flow rate according to 

§ 63.9632(c) and recording all 

information needed to document 

compliance with these requirements. 

(iv) If the daily average the sorbent 

injection rate or carrier gas flow rate is 

below the operating limit established for 

the control device, you must follow the 

corrective action procedures in 

paragraph (l) of this section. 

(j) For each affected indurating 

furnace using ACI to comply with the 

mercury emission limit in table 2 to this 

subpart, you must demonstrate 

continuous compliance by meeting the 

requirements of paragraphs (j)(1) or (2) 

of this section. 

(1) If you use CEMS to demonstrate 

compliance, you must comply with the 

requirements in paragraphs (j)(1)(i) and 

(ii) of this section. 

(i) You must operate a mercury CEMS 

in accordance with performance 

specification 12A at 40 CFR part 60, 

appendix B; these monitoring systems 

must be quality assured according to 

procedure 5 of 40 CFR 60, appendix F. 

You must demonstrate compliance with 

the mercury emissions limit using a 30- 

day rolling average of these 1-hour 

mercury concentrations or mass 

emissions rates, including CEMS data 

during startup and shutdown as defined 

in this subpart, calculated using 

equation 19–19 in section 12.4.1 of EPA 

Reference Method 19 at 40 CFR part 60, 

appendix A–7 of this part. 

(ii) Owners or operators using a 

mercury CEMS to determine mass 

emission rate must install, operate, 

calibrate and maintain an instrument for 

continuously measuring and recording 

the mercury mass emissions rate to the 

atmosphere according to the 

requirements of performance 

specification 6 at 40 CFR part 60, 

appendix B and conducting an annual 

relative accuracy test of the continuous 

emission rate monitoring system 

according to section 8.2 of performance 

specification 6. 


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(2) If you do not use CEMS to 

demonstrate compliance, you must 

demonstrate continuous compliance by 

meeting the requirements of paragraphs 

(j)(2)(i) through (iv) of this section. 

(i) Maintain the daily average 

activated carbon injection rate and 

carrier gas flow rate at or above the 

minimum level established during the 

most recent performance test. 

(ii) Operate and maintain each CPMS 

used to measure the activated carbon 

injection rate according to § 63.9632(h) 

and the carrier gas flow rate according 

to § 63.9632(i), and record all 

information needed to document 

compliance with these requirements. 

(iii) Collect and reduce monitoring 

data for the activated carbon injection 

rate and carrier gas flow rate according 

to § 63.9632(c) and record all 

information needed to document 

conformance with these requirements. 

(iv) If the daily average of the 

activated carbon injection rate or carrier 

gas flow rate is below the operating 

limit established for the control device, 

you must follow the corrective action 

procedures in paragraph (l) of this 

section. 

(k) If you use an air pollution control 

device other than a wet scrubber, 

dynamic wet scrubber, dry ESP, wet 

ESP, DSI, ACI, or baghouse, you must 

submit a site-specific monitoring plan in 

accordance with § 63.9631(f). The sitespecific monitoring plan must include 

the site-specific procedures for 

demonstrating initial and continuous 

compliance with the corresponding 

operating limits. 

(l) If the daily average operating 

parameter value for an emission unit or 

group of similar emission units does not 

meet the corresponding established 

operating limit, you must then follow 

the procedures in paragraphs (l)(1) 

through (4) of this section. 

(1) You must initiate and complete 

initial corrective action within 10 

calendar days and demonstrate that the 

initial corrective action was successful. 

During any period of corrective action, 

you must continue to monitor, and 

record all required operating parameters 

for equipment that remains in operation. 

After the initial corrective action, if the 

daily average operating parameter value 

for the emission unit or group of similar 

emission units meets the operating limit 

established for the corresponding unit 

or group, then the corrective action was 

successful and the emission unit or 

group of similar emission units is in 

compliance with the established 

operating limits. 

(2) If the initial corrective action 

required in paragraph (l)(1) of this 

section was not successful, then you 

must complete additional corrective 

action within 10 calendar days and 

demonstrate that the subsequent 

corrective action was successful. During 

any period of corrective action, you 

must continue to monitor, and record all 

required operating parameters for 

equipment that remains in operation. If 

the daily average operating parameter 

value for the emission unit or group of 

similar emission units meets the 

operating limit established for the 

corresponding unit or group, then the 

corrective action was successful, and 

the emission unit or group of similar 

emission units is in compliance with 

the established operating limits. 

(3) If the second attempt at corrective 

action required in paragraph (l)(2) of 

this section was not successful, then 

you must repeat the procedures of 

paragraph (l)(2) of this section until the 

corrective action is successful. If the 

third attempt at corrective action is 

unsuccessful, you must conduct another 

performance test in accordance with the 

procedures in § 63.9622(f) and report to 

the Administrator as a deviation the 

third unsuccessful attempt at corrective 

action. 

(4) After the third unsuccessful 

attempt at corrective action, you must 

submit to the Administrator the written 

report required in paragraph (l)(3) of 

this section within 5 calendar days after 

the third unsuccessful attempt at 

corrective action. This report must 

notify the Administrator that a deviation 

has occurred and document the types of 

corrective measures taken to address the 

problem that resulted in the deviation of 

established operating parameters and 

the resulting operating limits. 

(m) If you elect to comply with the 

mercury limit in table 2 to this subpart 

using emissions averaging in accordance 

with an implementation plan approved 

under the provisions in § 63.9623(d), 

you must comply with the requirements 

in paragraphs (m)(1) through (5) of this 

section. 

(1) For furnaces included in the 

emissions averaging group that do not 

use mercury CEMS, you must comply 

with the requirements in paragraph 

(m)(1)(i) or (ii) as applicable. 

(i) For furnaces equipped with ACI 

systems, you must comply with the 

requirements in paragraph (j) of this 

section. 

(ii) For furnaces equipped with a 

mercury control device or method other 

than ACI, you must comply with your 

site-specific monitoring plan in 

accordance with the requirements in 

paragraph (k) of this section. 

(2) For furnaces included in the 

emissions averaging group that use 

mercury CEMS, you must comply with 

the requirements in paragraph (i)(1) of 

this section. 

(3) Calculate the monthly productionweighted average emission rate using 

either the mercury CEMS data or 

mercury emission rate determined 

during the last performance test and the 

actual taconite pellet production data 

for each furnace included in the 

emissions averaging option, as shown in 

Equation 6 of this section. 

Where: 

Eg = Monthly production-weighted average 

mercury emission rate for month ‘‘g’’ for 

the group of indurating furnaces, lb/LT 

of pellets produced, 

Ef = Average mercury emission rate for 

furnace ‘‘f’’, as determined using either 

mercury CEMS data or the emission rate 

determined during the last compliance 

stack test and calculated using Equation 

5 of § 63.9621(d)(7)(i), lb/LT of pellets 

produced, 

Pf = Total monthly production of finished 

taconite pellets for furnace ‘‘f’’, in LT, 

and 

n = Number of furnaces in the averaging 

group. 

(4) Until 12 monthly weighted average 

emission rates have been accumulated, 

the monthly weighted average emissions 

rate, calculated as shown in paragraph 

(m)(3) of this section, must not exceed 

the mercury emission limit in table 3 of 

this subpart in any calendar month. 

(5) After 12 monthly weighted average 

emission rates have been accumulated, 

for each subsequent calendar month, 

you must use Equation 7 of this section 

to calculate the 12-month rolling 

average of the monthly weighted 

average emission rates for the current 

month and the previous 11 months. The 

12-month rolling weighted average 

emissions rate for the furnaces included 

in the group must not exceed the 

mercury emission limit in table 3 of this 

subpart. 

Where: 

Eavg = 12-month rolling average emission 

rate, lb/LT. 

Ei = Monthly weighted average for month ‘‘i’’ 

calculated as shown in Equation 6 of this 

section. 

(n) You may elect to demonstrate 

continuous compliance with the 

mercury limit in table 2 to this subpart 

by adjusting the activated carbon 

injection rate based on the taconite 

pellet production rate. You must 

comply with the requirements in 


ddrumheller on DSK120RN23PROD with RULES4ER06MR24.054</GPH> ER06MR24.055</GPH>

Lr=1(Er x Pr) (Eq. 6) 

Eg = L[=1pf 
Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16435 

paragraphs (n)(1) through (7) of this 

section. 

(1) Measure the activated carbon 

injection and mercury emissions rate at 

a minimum of three different 

production levels corresponding to the 

maximum, minimum and median 

finished taconite pellet production 

rates, using the methods specified in 

§ 63.9620(k). 

(2) Develop a correlation curve by 

plotting the production rate and 

corresponding carbon injection rate for 

the maximum, median and minimum 

production rates. Use only data where 

the mercury emission rate is below the 

applicable mercury emissions standard 

in table 2 to this subpart. Plot the 

production rates as the independent (or 

x) variable and the activated carbon 

injection rate as the dependent (or y) 

variable for each pellet production rate. 

Construct the graph by drawing straight 

line segments between each point 

plotted. 

(3) You must develop and submit to 

the applicable regulatory authority for 

review and approval, an 

implementation plan no later than 180 

days before the date you intend to 

demonstrate compliance by adjusting 

the activated carbon injection rate based 

on the taconite pellet production. You 

must include the information listed in 

paragraphs (n)(3)(i) through (iv) of this 

section in your implementation plan. 

(i) Identification of the indurating 

furnace, including the typical maximum 

and minimum taconite pellet 

production rate, mercury control 

technology installed, and types of fuel(s) 

that will be burned. 

(ii) The mercury emissions and 

activated carbon injection rates at 

maximum, median and minimum 

taconite pellet production rates, and the 

methods used to measure the mercury 

emissions, activated carbon injection 

rate and taconite pellet production. 

(iii) The correlation curve developed 

in paragraph (n)(2) of this section. 

(iv) The date on which you are 

requesting to commence adjusting the 

activated carbon rate based on the 

taconite production rate. 

(4) Install, calibrate, maintain, and 

operate a CPMS to monitor and record 

the activated carbon injection rate and 

taconite pellet production rate. 

(5) Maintain the carbon injection rate 

at or above the rate established by the 

correlation curve corresponding to the 

taconite pellet production rate. If the 

taconite pellet production rate drops 

below the minimum rate established in 

paragraph (n)(3) of this section, you 

must maintain the activated carbon 

injection rate at or above the rate 

established for the minimum taconite 

pellet production rate. 

(6) Keep records of the activated 

carbon injection rate and taconite pellet 

production rate for each hour of 

operation in order to demonstrate that 

the activated carbon injection rate 

remains in compliance with paragraph 

(n)(5) of this section. 

(7) Establish a new correlation curve 

at least twice per 5-year permit term. 

■ 15. Section 63.9636 is amended by 

revising paragraph (a) introductory text 

to read as follows: 

§ 63.9636 How do I demonstrate 

continuous compliance with the operation 

and maintenance requirements that apply to 

me? 

(a) For each control device used to 

comply with an emission standard in 

§ 63.9590(a), you must demonstrate 

continuous compliance with the 

operation and maintenance 

requirements in § 63.9600(b) by 

completing the requirements of 

paragraphs (a)(1) through (4) of this 

section. 

* * * * * 

■ 16. Section 63.9637 is amended by 

revising paragraph (a) to read as follows: 

§ 63.9637 What other requirements must I 

meet to demonstrate continuous 

compliance? 

(a) Deviations. You must report each 

instance in which you did not meet 

each emission limitation in tables 1 

through 3 to this subpart that applies to 

you. You also must report each instance 

in which you did not meet the work 

practice standards in § 63.9591 and each 

instance in which you did not meet 

each operation and maintenance 

requirement in § 63.9600 that applies to 

you. These instances are deviations 

from the emission limitations, work 

practice standards, and operation and 

maintenance requirements in this 

subpart. These deviations must be 

reported in accordance with the 

requirements in § 63.9641. 

* * * * * 

■ 17. Section 63.9640 is amended by 

adding paragraphs (f) and (g) to read as 

follows: 

§ 63.9640 What notifications must I submit 

and when? 

* * * * * 

(f) If you elect to use CEMS to 

demonstrate compliance with the 

mercury standards in table 2 to this 

subpart, you must submit a notification 

of intent to use CEMS at least one 

month prior to making the change. If 

you are currently using CEMS to 

demonstrate compliance with the 

mercury standards, you must submit a 

notification of intent to cease using 

CEMS to demonstrate compliance at 

least 180 days prior to making the 

change. 

(g) If you elect to use the mercury 

emissions averaging compliance option, 

you must submit a notification of intent 

at least 180 days prior to making the 

change. If you are currently using the 

mercury emissions averaging 

compliance option, you must submit a 

notification of intent to cease using 

emissions averaging at least 30 days 

prior to making the change. 

■ 18. Section 63.9641 is amended by: 

■ a. Revising paragraph (b)(6); 

■ b. Revising and republishing 

paragraph (b)(8); 

■ c. Revising paragraphs (c), (e) and 

(f)(3); and 

■ d. Adding paragraph (i). 

The revisions and additions read as 

follows: 

§ 63.9641 What reports must I submit and 

when? 

* * * * * 

(b) * * * 

(6) If there were no periods during 

which a continuous monitoring system 

(including a CPMS, COMS, or CEMS) 

was out-of-control as specified in 

§ 63.8(c)(7), then provide a statement 

that there were no periods during which 

a continuous monitoring system was 

out-of-control during the reporting 

period. 

* * * * * 

(8) On or before January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, for each 

deviation from an emission limitation 

occurring at an affected source where 

you are using a continuous monitoring 

system (including a CPMS or COMS) to 

comply with the emission limitation in 

this subpart, you must include the 

information in paragraphs (b)(1) through 

(4) of this section and the information 

in paragraphs (b)(8)(i) through (xi) of 

this section. This includes periods of 

startup, shutdown, and malfunction. 

After January 25, 2021, for affected 

sources that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, for each deviation 

from an emission limitation occurring at 

an affected source where you are using 

a continuous monitoring system 

(including a CPMS, COMS, or CEMS) to 

comply with the emission limitation in 

this subpart, you must include the 

information in paragraphs (b)(1) through 


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(4) of this section and the information 

in paragraphs (b)(8)(i) through (xi) of 

this section. 

(i) The date and time that each 

malfunction started and stopped. 

(ii) The start date, start time, and 

duration in hours (or minutes for 

COMS) that each continuous monitoring 

system was inoperative, except for zero 

(low-level) and high-level checks. 

(iii) The start date, start time, and 

duration that each continuous 

monitoring system was out-of-control, 

including the information in 

§ 63.8(c)(8). 

(iv) On or before January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, for each 

affected source or equipment, the date 

and time that each deviation started and 

stopped, the cause of the deviation, and 

whether each deviation occurred during 

a period of startup, shutdown, or 

malfunction or during another period. 

After January 25, 2021, for affected 

sources that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, for each affected 

source or equipment, the date and time 

that each deviation started and stopped, 

the cause of the deviation, and whether 

each deviation occurred during a period 

of malfunction or during another period 

(v) The total duration of all deviations 

for each Continuous Monitoring System 

(CMS) during the reporting period, the 

total operating time in hours of the 

affected source during the reporting 

period, and the total duration as a 

percent of the total source operating 

time during that reporting period. 

(vi) On or before January 25, 2021, for 

affected sources that commenced 

construction or reconstruction on or 

before September 25, 2019, a breakdown 

of the total duration of the deviations 

during the reporting period including 

those that are due to startup, shutdown, 

control equipment problems, process 

problems, other known causes, and 

other unknown causes. After January 25, 

2021, for affected sources that 

commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, a breakdown of the 

total duration of the deviations during 

the reporting period including those 

that are due to control equipment 

problems, process problems, other 

known causes, and other unknown 

causes. 

(vii) The total duration of continuous 

monitoring system downtime for each 

continuous monitoring system during 

the reporting period, the total operating 

time in hours of the affected source 

during the reporting period, and the 

total duration of continuous monitoring 

system downtime as a percent of the 

total source operating time during the 

reporting period. 

(viii) A brief description of the 

process units. 

(ix) The monitoring equipment 

manufacturer and model number and 

the pollutant or parameter monitored. 

(x) The date of the latest continuous 

monitoring system certification or audit. 

(xi) A description of any changes in 

continuous monitoring systems, 

processes, or controls since the last 

reporting period. 

(c) Submitting compliance reports 

electronically. Beginning on January 25, 

2021, submit all subsequent compliance 

reports to the EPA via CEDRI, which can 

be accessed through the EPA’s Central 

Data Exchange (CDX) (https://

cdx.epa.gov/). The EPA will make all 

the information submitted through 

CEDRI available to the public without 

further notice to you. Do not use CEDRI 

to submit information you claim as 

confidential business information (CBI). 

Anything submitted using CEDRI cannot 

later be claimed to be CBI. You must use 

the appropriate electronic report 

template on the CEDRI website (https:// 

www.epa.gov/electronic-reporting-airemissions/compliance-and-emissionsdata-reporting-interface-cedri) for this 

subpart. The report must be submitted 

by the deadline specified in this 

subpart, regardless of the method in 

which the report is submitted. Although 

we do not expect persons to assert a 

claim of CBI, if persons wish to assert 

a CBI claim, submit a complete report, 

including information claimed to be 

CBI, to the EPA. The report must be 

generated using the appropriate form on 

the CEDRI website. Clearly mark the 

part or all of the information that you 

claim to be CBI. Information not marked 

as CBI may be authorized for public 

release without prior notice. 

Information marked as CBI will not be 

disclosed except in accordance with 

procedures set forth in 40 CFR part 2. 

Submit the file following the procedures 

in paragraph (c)(1) or (2) of this section. 

The same file with the CBI omitted must 

be submitted to the EPA via the EPA’s 

CDX as described earlier in this 

paragraph (c). All CBI claims must be 

asserted at the time of submission. 

Furthermore, under CAA section 114(c) 

emissions data is not entitled to 

confidential treatment, and EPA is 

required to make emissions data 

available to the public. Thus, emissions 

data will not be protected as CBI and 

will be made publicly available. On or 

before January 25, 2021, for affected 

sources that commenced construction or 

reconstruction on or before September 

25, 2019, if you had a startup, 

shutdown, or malfunction during the 

reporting period that is not consistent 

with your startup, shutdown, and 

malfunction plan you must submit an 

immediate startup, shutdown and 

malfunction report according to the 

requirements in § 63.10(d)(5)(ii). After 

January 25, 2021, for affected sources 

that commenced construction or 

reconstruction on or before September 

25, 2019, and after July 28, 2020, or 

upon start-up, which ever date is later, 

for affected sources that commenced 

construction or reconstruction after 

September 25, 2019, an immediate 

startup, shutdown, and malfunction 

report is not required. 

(1) The preferred method to receive 

CBI is for it to be transmitted 

electronically using email attachments, 

File Transfer Protocol, or other online 

file sharing services. Electronic 

submissions must be transmitted 

directly to the OAQPS CBI Office at the 

email address oaqpscbi@epa.gov, and as 

described above, should include clear 

CBI markings and be flagged to the 

attention of the Taconite Iron Ore 

Processing Sector Lead. If assistance is 

needed with submitting large electronic 

files that exceed the file size limit for 

email attachments, and if you do not 

have your own file sharing service, 

please email oaqpscbi@epa.gov to 

request a file transfer link. 

(2) If you cannot transmit the file 

electronically, you may send CBI 

information through the postal service 

to the following address: U.S. EPA, 

Attn: OAQPS Document Control Officer 

and Taconite Iron Ore Processing Sector 

Lead, Mail Drop: C404–02, 109 T.W. 

Alexander Drive, P.O. Box 12055, RTP, 

NC 27711. The mailed CBI material 

should be double wrapped and clearly 

marked. Any CBI markings should not 

show through the outer envelope. 

* * * * * 

(e) Immediate corrective action report. 

If you had three unsuccessful attempts 

of applying corrective action as 

described in § 63.9634(l) on an emission 

unit or group of emission units, then 

you must submit an immediate 

corrective action report. Within 5 

calendar days after the third 

unsuccessful attempt at corrective 

action, you must submit to the 

Administrator a written report in 


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Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16437 

accordance with § 63.9634(l)(3) and (4). 

This report must notify the 

Administrator that a deviation has 

occurred and document the types of 

corrective measures taken to address the 

problem that resulted in the deviation of 

established operating parameters and 

the resulting operating limits. 

(f) * * * 

(3) Confidential business information 

(CBI). 

(i) The EPA will make all the 

information submitted through CEDRI 

available to the public without further 

notice to you. Do not use CEDRI to 

submit information you claim as CBI. 

Although we do not expect persons to 

assert a claim of CBI, if you wish to 

assert a CBI claim for some of the 

information submitted under paragraph 

(f)(1) or (2) of this section, you must 

submit a complete file, including 

information claimed to be CBI, to the 

EPA. 

(ii) The file must be generated using 

the EPA’s ERT or an alternate electronic 

file consistent with the XML schema 

listed on the EPA’s ERT website. 

(iii) Clearly mark the part or all of the 

information that you claim to be CBI. 

Information not marked as CBI may be 

authorized for public release without 

prior notice. Information marked as CBI 

will not be disclosed except in 

accordance with procedures set forth in 

40 CFR part 2. 

(iv) The preferred method to receive 

CBI is for it to be transmitted 

electronically using email attachments, 

File Transfer Protocol, or other online 

file sharing services. Electronic 

submissions must be transmitted 

directly to the OAQPS CBI Office at the 

email address oaqpscbi@epa.gov, and as 

described above, should include clear 

CBI markings and be flagged to the 

attention of the Group Leader, 

Measurement Policy Group. If assistance 

is needed with submitting large 

electronic files that exceed the file size 

limit for email attachments, and if you 

do not have your own file sharing 

service, please email oaqpscbi@epa.gov 

to request a file transfer link. 

(v) If you cannot transmit the file 

electronically, you may send CBI 

information through the postal service 

to the following address: U.S. EPA, 

Attn: OAQPS Document Control Officer 

and Measurement Policy Group Lead, 

Mail Drop: C404–02, 109 T.W. 

Alexander Drive, P.O. Box 12055, RTP, 

NC 27711. The mailed CBI material 

should be double wrapped and clearly 

marked. Any CBI markings should not 

show through the outer envelope. 

(vi) All CBI claims must be asserted 

at the time of submission. Anything 

submitted using CEDRI cannot later be 

claimed CBI. Furthermore, under CAA 

section 114(c), emissions data is not 

entitled to confidential treatment, and 

the EPA is required to make emissions 

data available to the public. Thus, 

emissions data will not be protected as 

CBI and will be made publicly available. 

(vii) You must submit the same file 

submitted to the CBI office with the CBI 

omitted to the EPA via the EPA’s CDX 

as described in § 63.9(k). 

* * * * * 

(i) Use of CEMS for mercury. If you 

use CEMS to demonstrate compliance 

with the mercury emissions limits in 

table 2 to this subpart, you must submit 

the results of the performance 

evaluation following the procedure 

specified in either paragraph (i)(1) or (2) 

of this section within 60 days after the 

date of completing each CEMS 

performance evaluation (as defined in 

§ 63.2). 

(1) For performance evaluations of 

continuous monitoring systems 

measuring relative accuracy test audit 

(RATA) pollutants that are supported by 

the EPA’s ERT as listed on the EPA’s 

ERT website at the time of the 

evaluation, you must submit the results 

of the performance evaluation to the 

EPA via the CEDRI. Performance 

evaluation data must be submitted in a 

file format generated through the use of 

the EPA’s ERT or an alternate file format 

consistent with the XML schema listed 

on the EPA’s ERT website. If you claim 

that some of the performance evaluation 

information being transmitted is CBI, 

you must submit a complete file 

generated through the use of the EPA’s 

ERT or an alternate electronic file 

consistent with the XML schema listed 

on the EPA’s ERT website, including 

information claimed to be CBI, on a 

compact disc, flash drive, or other 

commonly used electronic storage 

media to the EPA. The electronic media 

must be clearly marked as CBI and 

mailed to U.S. EPA/OAQPS/CORE CBI 

Office, Attention: Group Leader, 

Measurement Policy Group, MD C404– 

02, 4930 Old Page Rd., Durham, NC 

27703. The same ERT or alternate file 

with the CBI omitted must be submitted 

to the EPA via the EPA’s CDX as 

described earlier in this section. 

(2) For any performance evaluations 

of continuous monitoring systems 

measuring RATA pollutants that are not 

supported by the EPA’s ERT as listed on 

the ERT website at the time of the 

evaluation, you must submit the results 

of the performance evaluation to the 

Administrator at the appropriate 

address listed in § 63.13. 

■ 19. Section 63.9642 is amended by: 

■ a. Revising paragraph (b) introductory 

text; and 

■ b. Adding paragraphs (b)(5), (d), (e) 

and (f). 

The revisions and additions read as 

follows: 

§ 63.9642 What records must I keep? 

* * * * * 

(b) For each COMS and CEMS, you 

must keep the records specified in 

paragraphs (b)(1) through (5) of this 

section. 

* * * * * 

(5) If you use mercury CEMS to 

demonstrate compliance with the 

mercury emission standard in table 2 of 

the subpart in accordance with 

§ 63.9623(e), records of requests for 

alternatives to the relative accuracy test 

for CEMS as required in § 63.8(f)(6)(i). 

* * * * * 

(d) If you elect the mercury emissions 

averaging compliance alternative 

pursuant to § 63.9623(d), you must keep 

a copy of the emission averaging 

implementation plan required in 

§ 63.9623(d)(2), records of the taconite 

pellet production rate for each furnace 

included in the averaging, and all 

calculations required under 

§ 63.9634(m). 

(e) If you elect to adjust the activated 

carbon injection rate based on the 

taconite pellet production rate in 

accordance with the provisions in 

§ 63.9634(n), you must keep a copy of 

the activated carbon injection 

implementation plan and records of the 

taconite pellet production rate and 

activated carbon injection rate. 

(f) If you use CEMS to demonstrate 

compliance with the mercury emissions 

limits in table 2 to this subpart, you 

must keep records of the notifications 

required in § 63.9642(f). 

■ 20. Section 63.9650 is revised to read 

as follows: 

§ 63.9650 What parts of the General 

Provisions apply to me? 

Table 4 to this subpart shows which 

parts of the General Provisions in 

§§ 63.1 through 63.16 apply to you. 

■ 21. Section 63.9652 is amended by 

adding definitions in alphabetical order 

for ‘‘Activated carbon injection (ACI) 

system’’, ‘‘Dry sorbent injection (DSI) 

system’’, and ‘‘Electrostatic precipitator 

(ESP)’’ to read as follows: 

§ 63.9652 What definitions apply to this 

subpart? 

* * * * * 

Activated carbon injection (ACI) 

system means an add-on air pollution 

control system in which activated 

carbon or brominated activated carbon 

is injected into the flue gas steam 


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16438 Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 

upstream of a particulate matter control 

device to adsorb mercury in the exhaust 

stream. The absorbed mercury remains 

absorbed to the activated carbon and is 

collected in a primary or secondary 

particulate matter control device. 

* * * * * 

Dry sorbent injection (DSI) system 

means an add-on air pollution control 

system that injects dry alkaline sorbent 

(dry injection) or sprays an alkaline 

sorbent (spray dryer) to react with and 

neutralize acid gas in the exhaust stream 

forming a dry powder material that is 

collected by a primary or secondary 

particulate matter control device. 

* * * * * 

Electrostatic Precipitator (ESP) means 

a device that removes suspended 

particulate matter from flue exhaust by 

applying a high-voltage electrostatic 

charge to the particles, which are then 

attracted to and collected on a grounded 

plate. In a dry ESP, the particles are 

dislodged from the plate by rapping and 

are collected in a hopper positioned 

below the plate. In a wet ESP, 

particulates are removed from the plate 

by washing with water. 

* * * * * 

■ 22. Revise the table heading and 

introductory paragraph for table 1 to 

subpart RRRRR of part 63 to read as 

follows: 

Table 1 to Subpart RRRRR of Part 63— 

Particulate Matter Emission Limits 

As required in § 63.9590(a), you must 

comply with each applicable particulate 

matter emission limit in the following 

table: 

* * * * * 

■ 22. Table 2 to subpart RRRRR is 

redesignated as table 4 to subpart 

RRRRR. 

■ 23. Add a new table 2 to subpart 

RRRRR to read as follows: 

TABLE 2 TO SUBPART RRRRR OF PART 63—MERCURY EMISSION LIMITS FOR INDURATING FURNACES

[As required in § 63.9590(a), you must comply with each applicable mercury emission limit in the following table:] 

For . . . You must meet the following emission limits . . . 

1. Indurating furnaces constructed or reconstructed before May 15, 2023.Either: 

(1) Mercury emissions from each furnace must not exceed 1.4 × 10¥5 lb/LT of taconite pellets produced, or 

(2) Production-weighted average mercury emissions for a group of indurating furnaces, calculated according to Equation 6 in § 63.9634(m)(3), must not exceed 1.3 

× 10¥5 lb/LT. 

2. Indurating furnaces constructed or reconstructed on or 

after May 15, 2023.

Mercury emissions from each furnace must not exceed 2.6 × 10¥6 lb/LT. 

■ 24. Add Table 3 to Subpart RRRRR to 

read as follows: 

TABLE 3 TO SUBPART RRRRR OF PART 63—HYDROGEN CHLORIDE AND HYDROGEN FLUORIDE EMISSION LIMITS FOR

INDURATING FURNACES

[As required in § 63.9590(a), you must comply with each applicable hydrogen chloride and hydrogen fluoride emission limit in the following table:] 

For . . . You must meet the following emission limits . . . 

1. Indurating furnaces constructed or reconstructed before May 15, 2023.Hydrogen chloride emissions must not exceed 4.6 × 10¥2 lb/Long Ton of taconite 

pellets produced. 

Hydrogen fluoride emissions must not exceed 1.2 × 10¥2 lb/Long Ton of taconite 

pellets produced. 

2. Indurating furnaces constructed or reconstructed on or 

after May 15, 2023.

Hydrogen chloride emissions must not exceed 4.4 × 10¥4 lb/Long Ton of taconite 

pellets produced 

Hydrogen fluoride emissions must not exceed 3.3 × 10¥4 lb/Long Ton of taconite 

pellets produced. 

■ 25. Revise newly redesignated table 4 

to subpart RRRRR to read as follows: 

TABLE 4 TO SUBPART RRRRR OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART RRRRR OF PART 63 

[As required in § 63.9650, you must comply with the requirements of the NESHAP General Provisions (40 CFR part 63, subpart A) shown in the 

following table:] 

Citation Summary of requirement Am I subject to this requirement? Explanations 

§ 63.1(a)(1)–(4) .......... Applicability .......................................... Yes.

§ 63.1(a)(5) ................ [Reserved] ........................................... No.

§ 63.1(a)(6) ................ Applicability .......................................... Yes.

§ 63.1(a)(7)–(9) .......... [Reserved] ........................................... No.

§ 63.1(a)(10)–(14) ...... Applicability .......................................... Yes.

§ 63.1(b)(1) ................ Initial Applicability Determination ........ Yes.

§ 63.1(b)(2) ................ [Reserved] ........................................... No.

§ 63.1(b)(3) ................ Initial Applicability Determination ........ Yes.

§ 63.1(c)(1)–(2) .......... Applicability After Standard Established, Permit Requirements.Yes.


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Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16439 

TABLE 4 TO SUBPART RRRRR OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART RRRRR OF PART

63—Continued 

[As required in § 63.9650, you must comply with the requirements of the NESHAP General Provisions (40 CFR part 63, subpart A) shown in the 

following table:] 

Citation Summary of requirement Am I subject to this requirement? Explanations 

§ 63.1(c)(3)–(4) .......... [Reserved] ........................................... No.

§ 63.1(c)(5) ................. Area Source Becomes Major .............. Yes.

§ 63.1(c)(6) ................. Reclassification .................................... Yes.

§ 63.1(d) ..................... [Reserved] ........................................... No.

§ 63.1(e) ..................... Equivalency of Permit Limits ............... Yes.

§ 63.2 ......................... Definitions ............................................ Yes.

§ 63.3(a)–(c) ............... Units and Abbreviations ...................... Yes.

§ 63.4(a)(1)–(2) .......... Prohibited Activities ............................. Yes.

§ 63.4(a)(3)–(5) .......... [Reserved] ........................................... No.

§ 63.4(b)–(c) ............... Circumvention, Fragmentation ............ Yes.

§ 63.5(a)(1)–(2) .......... Construction/Reconstruction, Applicability.Yes.

§ 63.5(b)(1) ................ Construction/Reconstruction, Applicability.Yes.

§ 63.5(b)(2) ................ [Reserved] ........................................... No.

§ 63.5(b)(3)–(4) .......... Construction/Reconstruction, Applicability.Yes.

§ 63.5(b)(5) ................ [Reserved] ........................................... No.

§ 63.5(b)(6) ................ Applicability .......................................... Yes.

§ 63.5(c) ..................... [Reserved] ........................................... No.

§ 63.5(d)(1)–(4) .......... Application for Approval of Construction or Reconstruction.Yes.

§ 63.5(e) ..................... Approval of Construction or Reconstruction.Yes.

§ 63.5(f) ...................... Approval Based on State Review ....... Yes.

§ 63.6(a) ..................... Compliance with Standards and Maintenance Requirements.Yes.

§ 63.6(b)(1)–(5) .......... Compliance Dates for New/Reconstructed Sources.Yes.

§ 63.6(b)(6) ................ [Reserved] ........................................... No.

§ 63.6(b)(7) ................ Compliance Dates for New/Reconstructed Sources.Yes.

§ 63.6(c)(1)–(2) .......... Compliance Dates for Existing 

Sources.

Yes.

§ 63.6(c)(3)–(4) .......... [Reserved] ........................................... No.

§ 63.6(c)(5) ................. Compliance Dates for Existing 

Sources.

Yes.

§ 63.6(d) ..................... [Reserved] ........................................... No.

§ 63.6(e)(1)(i) ............. Operation and Maintenance Requirements—General Duty to Minimize 

Emissions.

Yes, on or before the compliance date 

specified in § 63.9600(a). No, after 

the compliance date specified in 

§ 63.9600(a).

See § 63.9600(a) for general duty requirement. 

§ 63.6(e)(1)(ii) ............ Operation and Maintenance Requirements—Requirement to Correct 

Malfunction as Soon as Possible.

No.

§ 63.6(e)(1)(iii) ............ Operation and Maintenance Requirements—Enforceability.Yes.

§ 63.6(e)(2) ................ [Reserved] ........................................... No.

§ 63.6(e)(3) ................ Startup, Shutdown, Malfunction (SSM) 

Plan.

Yes, on or before the compliance date 

specified in § 63.9610(c). No, after 

the compliance date specified in 

§ 63.9610(c).

§ 63.6(f)(1) ................. SSM exemption ................................... No ........................................................ See § 63.9600(a). 

§ 63.6(f)(2)–(3) ........... Methods for Determining Compliance Yes.

§ 63.6(g)(1)–(3) .......... Alternative Nonopacity Standard ......... Yes.

§ 63.6(h), except 

(h)(1).

Compliance with Opacity and Visible 

Emission (VE) Standards.

No ........................................................ Opacity limits in subpart RRRRR are 

established as part of performance 

testing in order to set operating limits for ESPs. 

§ 63.6(h)(1) ................ Compliance except during SSM .......... No ........................................................ See § 63.9600(a). 

§ 63.6(i)(1)–(14) ......... Extension of Compliance .................... Yes.

§ 63.6(i)(15) ................ [Reserved] ........................................... No.

§ 63.6(i)(16) ................ Extension of Compliance .................... Yes.

§ 63.6(j) ...................... Presidential Compliance Exemption ... Yes.

§ 63.7(a)(1)–(2) .......... Applicability and Performance Test 

Dates.

No ........................................................ Subpart RRRRR specifies performance test applicability and dates. 

§ 63.7(a)(3)–(4) .......... Performance Testing Requirements ... Yes.

§ 63.7(b) ..................... Notification ........................................... Yes.

§ 63.7(c) ..................... Quality Assurance/Test Plan ............... Yes.


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TABLE 4 TO SUBPART RRRRR OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART RRRRR OF PART

63—Continued 

[As required in § 63.9650, you must comply with the requirements of the NESHAP General Provisions (40 CFR part 63, subpart A) shown in the 

following table:] 

Citation Summary of requirement Am I subject to this requirement? Explanations 

§ 63.7(d) ..................... Testing Facilities .................................. Yes.

§ 63.7(e)(1) ................ Conduct of Performance Tests ........... No ........................................................ See § 63.9621. 

§ 63.7(e)(2)–(4) .......... Conduct of Performance Tests ........... Yes.

§ 63.7(f) ...................... Alternative Test Method ...................... Yes.

§ 63.7(g) ..................... Data Analysis ...................................... Yes ...................................................... Except this subpart specifies how and 

when the performance test results 

are reported. 

§ 63.7(h) ..................... Waiver of Tests ................................... Yes.

§ 63.8(a)(1)–(2) .......... Monitoring Requirements .................... Yes.

§ 63.8(a)(3) ................ [Reserved] ........................................... No.

§ 63.8(a)(4) ................ Additional Monitoring Requirements 

for Control Devices in § 63.11.

No ........................................................ Subpart RRRRR does not require 

flares. 

§ 63.8(b)(1)–(3) .......... Conduct of Monitoring ......................... Yes.

§ 63.8(c)(1)(i) ............. Operation and Maintenance of CMS .. Yes, on or before the compliance date 

specified in § 63.9632(b)(4). No, 

after the compliance date specified 

in § 63.9632(b)(4).

See § 63.9632 for operation and maintenance requirements for monitoring. See § 63.9600(a) for general 

duty requirement. 

§ 63.8(c)(1)(ii) ............. Spare parts for CMS Equipment ......... Yes.

§ 63.8(c)(1)(iii) ............ SSM Plan for CMS .............................. Yes, on or before the compliance date 

specified in § 63.9632(b)(4). No, 

after the compliance date specified 

in § 63.9632(b)(4).

§ 63.8(c)(2)–(3) .......... CMS Operation/Maintenance .............. Yes.

§ 63.8(c)(4) ................. Frequency of Operation for CMS ........ No ........................................................ Subpart RRRRR specifies requirements for operation of CMS. 

§ 63.8(c)(5)–(8) .......... CMS Requirements ............................. Yes ...................................................... CMS requirements in § 63.8(c)(5) and 

(6) apply only to COMS for dry 

ESPs. 

§ 63.8(d)(1)–(2) .......... Monitoring Quality Control ................... Yes.

§ 63.8(d)(3) ................ Monitoring Quality Control ................... No ........................................................ See § 63.9632(b)(5). 

§ 63.8(e) ..................... Performance Evaluation for CMS ....... Yes.

§ 63.8(f)(1)–(5) ........... Alternative Monitoring Method ............ Yes.

§ 63.8(f)(6) ................. Relative Accuracy Test Alternative 

(RATA).

Yes ...................................................... Only if using continuous emission 

monitoring systems to demonstrate 

compliance with Table 2 to this subpart. 

§ 63.8(g)(1)–(g)(4) ...... Data Reduction .................................... Yes.

§ 63.8(g)(5) ................ Data That Cannot Be Used ................. No ........................................................ Subpart RRRRR specifies data reduction requirements. 

§ 63.9 ......................... Notification Requirements ................... Yes ...................................................... Additional notifications for CMS in 

§ 63.9(g) apply to COMS for dry 

ESPs. 

§ 63.9(k) ..................... Electronic reporting procedures .......... Yes ...................................................... Only as specified in § 63.9(j) 

§ 63.10(a) ................... Recordkeeping and Reporting, Applicability and General Information.Yes.

§ 63.10(b)(1) .............. General Recordkeeping Requirements Yes.

§ 63.10(b)(2)(i) ........... Records of SSM .................................. No ........................................................ See § 63.9642 for recordkeeping 

when there is a deviation from a 

standard. 

§ 63.10(b)(2)(ii) .......... Recordkeeping of Failures to Meet a 

Standard.

No ........................................................ See § 63.9642 for recordkeeping of 

(1) date, time and duration; (2) listing of affected source or equipment, 

and an estimate of the quantity of 

each regulated pollutant emitted 

over the standard; and (3) actions 

to minimize emissions and correct 

the failure. 

§ 63.10(b)(2)(iii) .......... Maintenance Records ......................... Yes.

§ 63.10(b)(2)(iv) ......... Actions Taken to Minimize Emissions 

During SSM.

No.

§ 63.10(b)(2)(v) .......... Actions Taken to Minimize Emissions 

During SSM.

No.

§ 63.10(b)(2)(vi) ......... Recordkeeping for CMS Malfunctions Yes.

§ 63.10(b)(2)(vii)–(xii) Recordkeeping for CMS ...................... Yes.

§ 63.10(b)(2)(xiii) ........ Records for Relative Accuracy Test ... No.

§ 63.10(b)(2)(xiv) ........ Records for Notification ....................... Yes.

§ 63.10(b)(3) .............. Applicability Determinations ................ Yes.


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Federal Register / Vol. 89, No. 45 / Wednesday, March 6, 2024 / Rules and Regulations 16441 

TABLE 4 TO SUBPART RRRRR OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART RRRRR OF PART

63—Continued 

[As required in § 63.9650, you must comply with the requirements of the NESHAP General Provisions (40 CFR part 63, subpart A) shown in the 

following table:] 

Citation Summary of requirement Am I subject to this requirement? Explanations 

§ 63.10(c)(1)–(6) ........ Additional Recordkeeping Requirements for Sources with CMS.Yes.

§ 63.10(c)(7)–(8) ........ Records of Excess Emissions and Parameter Monitoring Exceedances for 

CMS.

.............................................................. Subpart RRRRR specifies recordkeeping requirements. 

§ 63.10(c)(9) ............... [Reserved] ........................................... No.

§ 63.10(c)(10)–(14) .... CMS Recordkeeping ........................... Yes.

§ 63.10(c)(15) ............. Use of SSM Plan ................................. No.

§ 63.10(d)(1)–(2) ........ General Reporting Requirements ....... Yes ...................................................... Except this subpart specifies how and 

when the performance test results 

are reported. 

§ 63.10(d)(3) .............. Reporting opacity or VE observations No ........................................................ Subpart RRRRR does not have opacity and VE standards that require 

the use of EPA Method 9 of appendix A–4 to 40 CFR part 60 or EPA 

Method 22 of appendix A–7 to 40 

CFR part 60. 

§ 63.10(d)(5) .............. SSM Reports ....................................... Yes, on or before the compliance date 

specified in § 63.9641(b)(4). No, 

after the compliance date specified 

in § 63.9641(b)(4).

See § 63.9641 for malfunction reporting requirements. 

§ 63.10(e) ................... Additional Reporting Requirements .... Yes, except a breakdown of the total 

duration of excess emissions due to 

startup/shutdown in63.10(e)(3)(vi)(I) 

is not required and when the summary report is submitted through 

CEDRI, the report is not required to 

be titled ‘‘Summary Report-Gaseous 

and Opacity Excess Emission and 

Continuous Monitoring System Performance.’’.

The electronic reporting template 

combines the information from the 

summary report and excess emission report with the Subpart 

RRRRR compliance report. 

§ 63.10(f) .................... Waiver for Recordkeeping or Reporting.Yes.

§ 63.11 ....................... Control Device and Work Practice Requirements.No ........................................................ Subpart RRRRR does not require 

flares. 

§ 63.12(a)–(c) ............. State Authority and Delegations ......... Yes.

§ 63.13(a)–(c) ............. State/Regional Addresses ................... Yes.

§ 63.14(a)–(t) ............. Incorporation by Reference ................. Yes.

§ 63.15(a)–(b) ............ Availability of Information and Confidentiality.Yes.

§ 63.16 ....................... Performance Track Provisions ............ Yes.

[FR Doc. 2024–02305 Filed 3–5–24; 8:45 am] 

BILLING CODE 6560–50–P 


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