Document ID: EPA-HQ-OAR-2017-0664-0001
Agency: epa
Document Type: Proposed Rule
Title: National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing Residual Risk and Technology Review
Posted Date: 2019-09-25T04:00Z

[Federal Register Volume 84, Number 186 (Wednesday, September 25, 2019)]
[Proposed Rules]
[Pages 50660-50695]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-19091]

[[Page 50659]]

Vol. 84

Wednesday,

No. 186

September 25, 2019

Part III

Environmental Protection Agency

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40 CFR Part 63

National Emission Standards for Hazardous Air Pollutants: Taconite Iron 
Ore Processing Residual Risk and Technology Review; Proposed Rule

  Federal Register / Vol. 84 , No. 186 / Wednesday, September 25, 2019 
/ Proposed Rules  

[[Page 50660]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2017-0664; FRL-9999-37-OAR]
RIN 2060-AT05

National Emission Standards for Hazardous Air Pollutants: 
Taconite Iron Ore Processing Residual Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This proposal presents the results of the U.S. Environmental 
Protection Agency's (EPA's) residual risk and technology reviews (RTRs) 
for the National Emission Standards for the Hazardous Air Pollutants 
(NESHAP) for Taconite Iron Ore Processing, as required under the Clean 
Air Act (CAA). Based on the results of the risk review, the EPA is 
proposing that risks from emissions of air toxics from this source 
category are acceptable and that the existing standards provide an 
ample margin of safety. Furthermore, under the technology review, the 
EPA identified no cost-effective developments in controls, practices, 
or processes to achieve further emissions reductions. Therefore, the 
EPA is proposing no revisions to the existing standards based on the 
RTRs. However, in this action the EPA is proposing: The removal of 
exemptions for periods of startup, shutdown, and malfunction (SSM) and 
clarifying that the emissions standards apply at all times; the 
addition of electronic reporting of performance test results and 
compliance reports; minor technical corrections and amendments to 
monitoring and testing requirements that would reduce the compliance 
burden on industry while continuing to be protective of the 
environment; and that regulation of a certain type compound emitted by 
one of the facilities, known as elongated mineral particulate, is not 
required under CAA section 112 because this compound is not a hazardous 
air pollutant (HAP) pursuant to the CAA. This action, if finalized, 
would result in improved monitoring, compliance, and implementation of 
the existing standards.

DATES: Comments. Comments must be received on or before November 12, 
2019. Under the Paperwork Reduction Act (PRA), comments on the 
information collection provisions are best assured of consideration if 
the Office of Management and Budget (OMB) receives a copy of your 
comments on or before October 25, 2019.
    Public hearing. If anyone contacts us requesting a public hearing 
on or before September 30, 2019, we will hold a hearing. Additional 
information about the hearing, if requested, will be published in a 
subsequent Federal Register document and posted at https://www.epa.gov/stationary-sources-air-pollution/taconite-iron-ore-processing-national-emission-standards-hazardous. See SUPPLEMENTARY INFORMATION for 
information on requesting and registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2017-0664, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: a-and-r-docket@epa.gov. Include Docket ID No. EPA-
HQ-OAR-2017-0664 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2017-0664.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2017-0664, Mail Code 28221T, 1200 
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except federal holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Mr. David Putney, Sector Policies and Programs Division 
(D243-02), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-2016; fax number: (919) 541-4991; 
and email address: putney.david@epa.gov. For specific information 
regarding the risk modeling methodology, contact Mr. Chris Sarsony, 
Health and Environmental Impacts Division (C539-02), Office of Air 
Quality Planning and Standards, U.S. Environmental Protection Agency, 
Research Triangle Park, North Carolina 27711; telephone number: (919) 
541-4843; fax number: (919) 541-0840; and email address: 
sarsony.chris@epa.gov. For questions about monitoring and testing 
requirements, contact Ms. Gerri Garwood, Sector Policies and Programs 
Division (D243-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-2406; fax number: (919) 541-4991; 
and email address: Garwood.gerri@epa.gov. For information about the 
applicability of the NESHAP to a particular entity, contact Mr. John 
Cox, Office of Enforcement and Compliance Assurance, U.S. Environmental 
Protection Agency, WJC South Building (Mail Code 2227A), 1200 
Pennsylvania Avenue NW, Washington DC 20460; telephone number: (202) 
564-1395; and email address: cox.john@epa.gov.

SUPPLEMENTARY INFORMATION: 
    Public hearing. Please contact Ms. Adrian Gates at (919) 541-4860 
or by email at gates.adrian@epa.gov to request a public hearing, to 
register to speak at the public hearing, or to inquire as to whether a 
public hearing will be held.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2017-0664. All documents in the docket are 
listed in Regulations.gov. Although listed, some information is not 
publicly available, e.g., Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. Certain 
other material, such as copyrighted material, is not placed on the 
internet and will be publicly available only in hard copy. Publicly 
available docket materials are available either electronically in 
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.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2017-0664. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://

[[Page 50661]]

www.regulations.gov/, including any personal information provided, 
unless the comment includes information claimed to be CBI or other 
information whose disclosure is restricted by statute. Do not submit 
information that you consider to be CBI or otherwise protected through 
https://www.regulations.gov/ or email. This type of information should 
be submitted by mail as discussed below.
    The EPA may publish any comment received to its public docket. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the Web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov/, your email address will be automatically 
captured and included as part of the comment that is placed in the 
public docket and made available on the internet. If you submit an 
electronic comment, the EPA recommends that you include your name and 
other contact information in the body of your comment and with any 
digital storage media you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov/ or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
any digital storage media that you mail to the EPA, mark the outside of 
the digital storage media as CBI and then identify electronically 
within the digital storage media the specific information that is 
claimed as CBI. In addition to one complete version of the comments 
that includes information claimed as CBI, you must submit a copy of the 
comments that does not contain the information claimed as CBI directly 
to the public docket through the procedures outlined in Instructions 
above. If you submit any digital storage media that does not contain 
CBI, mark the outside of the digital storage media clearly that it does 
not contain CBI. Information not marked as CBI will be included in the 
public docket and the EPA's electronic public docket without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 Code of Federal Regulations 
(CFR) part 2. Send or deliver information identified as CBI only to the 
following address: OAQPS Document Control Officer (C404-02), OAQPS, 
U.S. Environmental Protection Agency, Research Triangle Park, North 
Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2017-0664.
    Preamble acronyms and abbreviations. 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:

AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM-3 model
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CFR Code of Federal Regulations
D/F dioxins/furans
EMP elongated mineral particulate
EPA Environmental Protection Agency
ERPG emergency response planning guideline
ERT Electronic Reporting Tool
ESP electrostatic precipitator
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM-3 Human Exposure Model, Version 1.5.5
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
IRIS Integrated Risk Information System
km kilometer
MACT maximum achievable control technology
mg/m\3\ milligrams per cubic meter
MIR maximum individual risk
NAAQS National Ambient Air Quality Standards
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
pdf portable document format
PM particulate matter
POM polycyclic organic matter
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RTR residual risk and technology review
SAB Science Advisory Board
SSM startup, shutdown, and malfunction
The Court the United States Court of Appeals for the District of 
Columbia Circuit
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
UF uncertainty factor
UMRA Unfunded Mandates Reform Act
URE unit risk estimate

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
III. Analytical Procedures and Decision-Making
    A. How do we consider risk in our decision-making?
    B. How do we perform the technology review?
    C. How do we estimate post-MACT risk posed by the source 
category?
IV. Analytical Results and Proposed Decisions
    A. What are the analytical results and proposed decisions for 
this source category?
    B. What are the results and proposed decisions based on our 
technology review?
    C. What other actions are we proposing?
    D. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulation and Controlling 
Regulatory Costs

[[Page 50662]]

    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination with 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children from 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA)
    K. Executive Order 12898: Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that this proposed action is likely to 
affect. The proposed amendments, once promulgated, will be directly 
applicable to the affected sources. Federal, state, local, and tribal 
government entities would not be affected by this proposed action. As 
defined in the Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576, 
July 16, 1992) and Documentation for Developing the Initial Source 
Category List, Final Report (see EPA-450/3-91-030, July 1992), the 
Taconite Iron Ore Processing source category includes any operation 
engaged in separating and concentrating iron ore from taconite, a low 
grade iron ore to produce taconite pellets. The 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; concentration of the iron ore by 
magnetic separation or flotation; pelletization by wet tumbling with a 
balling drum or balling disc; induration using a straight grate or 
grate kiln furnace, and finished pellet handling.

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

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the internet. Following signature by the 
EPA Administrator, the EPA will post a copy of this proposed action at 
https://www.epa.gov/taconite-iron-ore-processing-national-emission-standards-hazardous. Following publication in the Federal Register, the 
EPA will post the Federal Register version of the proposal and key 
technical documents at this same website. Information on the overall 
RTR program is available at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A redline version of the regulatory language that incorporates the 
proposed changes in this action is available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2017-0664).

II. Background

A. What is the statutory authority for this action?

    The statutory authority for this action is provided by sections 112 
and 301 of the CAA, as amended (42 U.S.C. 7401 et seq.). Section 112 of 
the CAA establishes a two-stage regulatory process to develop standards 
for emissions of HAP from stationary sources. Generally, the first 
stage involves establishing technology-based standards and the second 
stage involves evaluating those standards that are based on maximum 
achievable control technology (MACT) to determine whether additional 
standards are needed to address any remaining risk associated with HAP 
emissions. This second stage is commonly referred to as the ``residual 
risk review.'' In addition to the residual risk review, the CAA also 
requires the EPA to review standards set under CAA section 112 every 8 
years to determine if there are ``developments in practices, processes, 
or control technologies'' that may be appropriate to incorporate into 
the standards. This review is commonly referred to as the ``technology 
review.'' When the two reviews are combined into a single rulemaking, 
it is commonly referred to as the ``risk and technology review.'' The 
discussion that follows identifies the most relevant statutory sections 
and briefly explains the contours of the methodology used to implement 
these statutory requirements. A more comprehensive discussion appears 
in the document titled CAA Section 112 Risk and Technology Reviews: 
Statutory Authority and Methodology, in the docket for this rulemaking.
    In the first stage of the CAA section 112 standard setting process, 
the EPA promulgates technology-based standards under CAA section 112(d) 
for categories of sources identified as emitting one or more of the HAP 
listed in CAA section 112(b). Sources of HAP emissions are either major 
sources or area sources, and CAA section 112 establishes different 
requirements for major source standards and area source standards. 
``Major sources'' are those that emit or have the potential to emit 10 
tons per year (tpy) or more of a single HAP or 25 tpy or more of any 
combination of HAP. All other sources are ``area sources.'' For major 
sources, CAA section 112(d)(2) provides that the technology-based 
NESHAP must reflect the maximum degree of emission reductions of HAP 
achievable (after considering cost, energy requirements, and non-air 
quality health and environmental impacts). These standards are commonly 
referred to as MACT standards. CAA section 112(d)(3) also establishes a 
minimum control level for MACT standards, known as the MACT ``floor.'' 
The EPA must also consider control options that are more stringent than 
the floor. Standards more stringent than the floor are commonly 
referred to as beyond-the-floor standards. In certain instances, as 
provided in CAA section 112(h), the EPA may set work practice standards 
where it is not feasible to prescribe or enforce a numerical emission 
standard. For area sources, CAA section 112(d)(5) gives the EPA 
discretion to set standards based on generally available control 
technologies or management practices (GACT standards) in lieu of MACT 
standards.
    The second stage in standard-setting focuses on identifying and 
addressing any remaining (i.e., ``residual'') risk according to CAA 
section 112(f). For source categories subject to MACT standards, 
section 112(f)(2) of the CAA requires the EPA to determine whether 
promulgation of additional standards or revised standards is needed to 
provide

[[Page 50663]]

an ample margin of safety to protect public health or to prevent an 
adverse environmental effect. Section 112(d)(5) of the CAA provides 
that this residual risk review is not required for categories of area 
sources subject to GACT standards. Section 112(f)(2)(B) of the CAA 
further expressly preserves the EPA's use of the two-step approach for 
developing standards to address any residual risk and the Agency's 
interpretation of ``ample margin of safety'' developed in the National 
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions 
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene 
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 
Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA 
notified Congress in the Risk Report that the Agency intended to use 
the Benzene NESHAP approach in making CAA section 112(f) residual risk 
determinations (EPA-453/R-99-001, p. ES-11). The EPA subsequently 
adopted this approach in its residual risk determinations and the 
United States Court of Appeals for the District of Columbia Circuit 
(the Court) upheld the EPA's interpretation that CAA section 112(f)(2) 
incorporates the approach established in the Benzene NESHAP. See NRDC 
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach incorporated into the CAA and used by the EPA to 
evaluate residual risk and to develop standards under CAA section 
112(f)(2) is a two-step approach. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\1\ of approximately 1 in 10 thousand.'' 54 FR 38045, September 14, 
1989. If risks are unacceptable, the EPA must determine the emissions 
standards necessary to reduce risk to an acceptable level without 
considering costs. In the second step of the approach, the EPA 
considers whether the emissions standards provide an ample margin of 
safety to protect public health ``in consideration of all health 
information, including the number of persons at risk levels higher than 
approximately 1 in 1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate emission standards necessary to provide an ample margin of 
safety to protect public health or determine that the standards being 
reviewed provide an ample margin of safety without any revisions. After 
conducting the ample margin of safety analysis, we consider whether a 
more stringent standard is necessary to prevent, taking into 
consideration costs, energy, safety, and other relevant factors, an 
adverse environmental effect.
---------------------------------------------------------------------------

    \1\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk if an individual were exposed to the maximum 
level of a pollutant for a lifetime.
---------------------------------------------------------------------------

    CAA section 112(d)(6) separately requires the EPA to review 
standards promulgated under CAA section 112 and revise them ``as 
necessary (taking into account developments in practices, processes, 
and control technologies)'' no less often than every 8 years. In 
conducting this review, which we call the ``technology review,'' the 
EPA is not required to recalculate the MACT floor. Natural Resources 
Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008). 
Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 
2013). The EPA may consider cost in deciding whether to revise the 
standards pursuant to CAA section 112(d)(6).

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

    The EPA initially promulgated the Taconite Iron Ore Processing 
NESHAP on October 30, 2003 (68 FR 61869), and it is codified at 40 CFR 
part 63, subpart RRRRR. This NESHAP regulates HAP emissions from new 
and existing taconite iron ore processing plants that are major sources 
of HAP. The Taconite Iron Ore Processing source category consists of 
eight individual facilities. Six of these facilities are in Minnesota 
and two are in Michigan.
    A taconite iron ore processing plant separates and concentrates 
iron ore from taconite, a low-grade iron ore containing 20- to 25-
percent iron, and produces taconite pellets, which are 60- to 65-
percent iron. Most of these pellets, nearly 98 percent, are sent to 
iron and steel manufacturers for use as feed material. The regulated 
sources are 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. The NESHAP also regulates fugitive 
emissions from stockpiles (including uncrushed and crushed ore and 
finished pellets), material transfer points, plant roadways, tailings 
basin, pellet loading areas, and yard areas.
    Taconite iron ore processing includes crushing and handling of the 
crude ore; concentrating (milling, magnetic separation, chemical 
flotation, etc.); agglomerating (dewatering, drying, and balling); 
indurating; and finished pellet handling.
    Taconite ore is obtained using a strip-mining process. Surface 
material and rock are removed to expose the taconite ore-bearing rock 
layers. Blasting is used to break up the taconite ore, which is then 
scooped up using large cranes with shovels and loaded into trucks or 
railcars. The ore is transported from the mine to the primary crushers.
    The ore crushing process begins when the taconite ore is dumped 
into the primary crusher which reduces the crude ore to a diameter of 
about 6 inches. Additional fine crushing further reduces the material 
to a size approximately \3/4\ of an inch in diameter. Intermediate 
vibratory screens remove the undersized material from the feed before 
it enters the next crusher. After it is adequately crushed, the ore is 
conveyed to storage bins at the concentrator building.
    In the concentrator building, water is typically added to the ore 
as it is conveyed into rod and ball mills which further grind the 
taconite ore to the consistency of coarse beach sand. Taconite ore is 
then separated from the waste rock material using magnetic separation. 
The iron content of the slurry is further increased using a combination 
of hydraulic concentration (gravity settling) and chemical flotation. 
Typically, application of water is utilized to suppress particulate and 
HAP metal emissions from the concentrating processes.
    From the concentration process, the taconite slurry enters the 
agglomerating process. In this part of the process, water is removed 
from the taconite slurry using vacuum disk filters or similar equipment 
and, at one plant, rotary dryers follow the disc filters and provide 
additional drying of the ore. The taconite is then mixed with binding 
agents in a balling drum which tumbles and rolls the taconite into 
unfired pellets. From the balling drum, the unfired pellets are 
conveyed to the indurating furnace.
    The unfired taconite pellets enter the induration furnace where 
they are hardened and oxidized at a temperature of between 2,290 to 
2,550 degrees Fahrenheit. Indurating furnaces are either straight grate 
furnaces or grate kiln furnaces. The hardened, finished pellets exit 
through the indurating furnace cooler.
    The finished pellet handling process begins at the point where the 
fired

[[Page 50664]]

taconite pellets exit the indurating furnace cooler (i.e., pellet 
loadout) and ends at the finished pellet stockpile. The finished pellet 
handling process includes finished pellet screening, transfer, and 
storage.
    Ore crushing and handling, ore drying, and finished pellet handling 
are all potentially significant points of particulate matter (PM) 
emissions. Taconite ore inherently contains trace metals, such as 
manganese, chromium, cobalt, arsenic, and lead, which are listed as HAP 
under CAA section 112(b) and the PM emissions from these three 
operations can contain these metal compounds. Manganese compounds are 
the predominant metal HAP emitted from ore crushing and handling, ore 
drying, and finished pellet handling.
    The indurating furnaces are the most significant sources of HAP 
emissions, accounting for about 99 percent of the total HAP emissions 
from the Taconite Iron Ore Processing source category. Three types of 
HAP are emitted from the waste gas stacks of indurating furnaces. The 
first type of HAP is metallic HAP existing as a portion of PM from the 
taconite ore or from fuel (such as coal) fed into the furnaces. 
Manganese and arsenic compounds are the predominant metal HAP emitted 
by indurating furnaces. Other metal HAP emitted from these furnaces 
include chromium, lead, nickel, cadmium, and mercury. The second type 
of HAP is organic HAP, primarily formaldehyde, resulting as a product 
of incomplete fuel combustion. The third type of HAP is acid gases, 
such as hydrochloric acid (HCl) and hydrofluoric acid (HF). Fluorine 
and chlorine compounds in the raw materials are liberated during the 
indurating process and combine with moisture in the exhaust to form HCl 
and HF.
    The current rule requires compliance with emission limits, 
operating limits for control devices, and work practice standards at 
all times except during periods of SSM. The emission limits are in the 
form of PM limits, which are a surrogate for metal HAP emissions as 
well as for HCl and HF for indurating furnaces. Emission limitations, 
shown in Table 2, apply to each ore crushing and handling operation, 
ore dryer, indurating furnace, and finished pellet handling operation.

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

    Performance tests are required to demonstrate compliance with the 
emission limits and must be conducted twice per 5-year period. The rule 
also requires that site-specific operating limits be established during 
the performance test for each control device and monitored continuously 
to demonstrate continuous compliance. Table 3 lists the operating 
parameters that must be established during the performance test and 
then monitored continuously.

    Table 3--Operating Parameters Monitored To Demonstrate Continuous
                               Compliance
------------------------------------------------------------------------
                                   Monitoring device      Parameters
       Control device \1\                 \2\              monitored
------------------------------------------------------------------------
Baghouse........................  Bag leak detection  Relative change in
                                   system.             PM loading.
Dynamic wet scrubber............  CPMS..............  Scrubber water
                                                       flow rate and
                                                       either fan
                                                       amperage or
                                                       pressure drop.
Wet scrubbers (other than         CPMS..............  Pressure drop and
 dynamic wet scrubbers).                               scrubber water
                                                       flow rate.
Dry ESP.........................  COMS, or CPMS.....  Opacity Secondary
                                                       voltage and
                                                       secondary
                                                       current.
Wet ESP.........................  CPMS..............  Secondary voltage,
                                                       stack outlet
                                                       temperature, and
                                                       water flow rate.
------------------------------------------------------------------------
\1\ ESP = electrostatic precipitator.
\2\ CPMS = continuous parameter monitoring system, COMS = continuous
  opacity monitor.

    The current rule also includes operation and maintenance 
requirements for pellet indurating furnaces to ensure good combustion 
practices to minimize emissions of organic HAP (combustion-related HAP 
such as formaldehyde) and requires that sources of fugitive dust 
emissions at taconite iron ore processing plants be controlled using 
work practices described in detail in a facility's fugitive dust 
emissions control plan. The plan must address fugitive emissions from 
stockpiles (including uncrushed and crushed ore and finished pellets), 
material transfer points, plant roadways, tailings basin, pellet 
loading areas, and yard areas.

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

    For the Taconite Iron Ore Processing source category, the EPA did 
not use data collection requests to gather emissions and other related 
data used in the analysis of risks. The data and data sources used to 
support this action are described in section II.D below.

[[Page 50665]]

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

    Information used to estimate emissions from taconite iron ore 
processing plants was obtained primarily from the EPA's 2014 National 
Emissions Inventory (NEI) database (https://www.epa.gov/air-emissions-inventories/2014-national-emissions-inventory-nei-data) and 
supplemental information submitted by industry. Data on the numbers, 
types, dimensions, and locations of the emission points for each 
facility were obtained from the NEI, state agencies, Google 
EarthTM, and taconite iron ore processing industry staff. 
The HAP emissions from taconite iron ore processing plants were 
categorized by source into one of the five emission process groups as 
follows: Ore crushing and handling operations; ore drying; pellet 
induration; pellet handling operations; and fugitive sources. Data on 
HAP emissions, including the HAP emitted, emission source, emission 
rates, stack parameters (such as temperature, velocity, flow, etc.), 
and latitude and longitude were compiled into a draft modeling file.
    To ensure the quality of the emissions data, the EPA subjected the 
draft modeling file to a variety of quality checks. The draft modeling 
file for each facility was made available to the facility to review the 
emission release parameters and the emission rates for their 
facilities. Source latitudes and longitudes reported by facilities were 
checked in Google EarthTM to verify accuracy and were 
corrected as needed. These and other quality control efforts resulted 
in a more accurate emissions dataset. The document, Development of the 
Residual Risk Review Emissions Dataset for the Taconite Iron Ore 
Processing Source Category, provides a detailed description of the 
development of the modeling dataset and is available in the docket for 
this rulemaking.

III. Analytical Procedures and Decision-Making

    In this section, we describe the analyses performed to support the 
proposed decisions for the RTR and other issues addressed in this 
action.

A. How do we consider risk in our decision-making?

    As discussed in section II.A of this preamble and in the Benzene 
NESHAP, in evaluating and developing standards under CAA section 
112(f)(2), we apply a two-step approach to determine whether or not 
risks are acceptable and to determine if the standards provide an ample 
margin of safety to protect public health. As explained in the Benzene 
NESHAP, ``the first step judgment on acceptability cannot be reduced to 
any single factor'' and, thus, ``[t]he Administrator believes that the 
acceptability of risk under section 112 is best judged on the basis of 
a broad set of health risk measures and information.'' 54 FR 38046, 
September 14, 1989. Similarly, with regard to the ample margin of 
safety determination, ``the Agency again considers all of the health 
risk and other health information considered in the first step. Beyond 
that information, additional factors relating to the appropriate level 
of control will also be considered, including cost and economic impacts 
of controls, technological feasibility, uncertainties, and any other 
relevant factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. The EPA conducts a risk 
assessment that provides estimates of the MIR posed by the HAP 
emissions from each source in the source category, the hazard index 
(HI) for chronic exposures to HAP with the potential to cause noncancer 
health effects, and the hazard quotient (HQ) for acute exposures to HAP 
with the potential to cause noncancer health effects.\2\ The assessment 
also provides estimates of the distribution of cancer risk within the 
exposed populations, cancer incidence, and an evaluation of the 
potential for an adverse environmental effect. The scope of the EPA's 
risk analysis is consistent with the EPA's response to comments on our 
policy under the Benzene NESHAP where the EPA explained that:
---------------------------------------------------------------------------

    \2\ The MIR is defined as the cancer risk associated with a 
lifetime of exposure at the highest concentration of HAP where 
people are likely to live. The HQ is the ratio of the potential HAP 
exposure concentration to the noncancer dose-response value; the HI 
is the sum of HQs for HAP that affect the same target organ or organ 
system.

``[t]he policy chosen by the Administrator permits consideration of 
multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, 
the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be 
weighed in each individual case. This approach complies with the 
Vinyl Chloride mandate that the Administrator ascertain an 
acceptable level of risk to the public by employing his expertise to 
assess available data. It also complies with the Congressional 
intent behind the CAA, which did not exclude the use of any 
particular measure of public health risk from the EPA's 
consideration with respect to CAA section 112 regulations, and 
thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in his judgment, believes are 
---------------------------------------------------------------------------
appropriate to determining what will `protect the public health'.''

    See 54 FR 38057, September 14, 1989. Thus, the level of the MIR is 
only one factor to be weighed in determining acceptability of risk. The 
Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes an MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. In other words, risks that include 
an MIR above 100-in-1 million may be determined to be acceptable, and 
risks with an MIR below that level may be determined to be 
unacceptable, depending on all of the available health information. 
Similarly, with regard to the ample margin of safety analysis, the EPA 
stated in the Benzene NESHAP that: ``EPA believes the relative weight 
of the many factors that can be considered in selecting an ample margin 
of safety can only be determined for each specific source category. 
This occurs mainly because technological and economic factors (along 
with the health-related factors) vary from source category to source 
category.'' Id. at 38061. We also consider the uncertainties associated 
with the various risk analyses, as discussed earlier in this preamble, 
in our determinations of acceptability and ample margin of safety.
    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify the HAP risk that may be associated with emissions 
from other facilities that do not include the source category under 
review, mobile source emissions, natural source emissions, persistent 
environmental pollution, or atmospheric transformation in the vicinity 
of the sources in the category.
    The EPA understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
noncancer

[[Page 50666]]

risk, where pollutant-specific exposure health reference levels (e.g., 
reference concentrations (RfCs)) are based on the assumption that 
thresholds exist for adverse health effects. For example, the EPA 
recognizes that, although exposures attributable to emissions from a 
source category or facility alone may not indicate the potential for 
increased risk of adverse noncancer health effects in a population, the 
exposures resulting from emissions from the facility in combination 
with emissions from all of the other sources (e.g., other facilities) 
to which an individual is exposed may be sufficient to result in an 
increased risk of adverse noncancer health effects. In May 2010, the 
Science Advisory Board (SAB) advised the EPA ``that RTR assessments 
will be most useful to decision makers and communities if results are 
presented in the broader context of aggregate and cumulative risks, 
including background concentrations and contributions from other 
sources in the area.'' \3\
---------------------------------------------------------------------------

    \3\ Recommendations of the SAB Risk and Technology Review 
Methods Panel are provided in their report, which is available at: 
https://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA incorporates 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this action. The Agency (1) conducts facility-wide 
assessments, which include source category emission points, as well as 
other emission points within the facilities; (2) combines exposures 
from multiple sources in the same category that could affect the same 
individuals; and (3) for some persistent and bioaccumulative 
pollutants, analyzes the ingestion route of exposure. In addition, the 
RTR risk assessments consider aggregate cancer risk from all 
carcinogens and aggregated noncancer HQs for all noncarcinogens 
affecting the same target organ or target organ system.
    Although we are interested in placing source category and facility-
wide HAP risk in the context of total HAP risk from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. Estimates of total HAP risk from emission 
sources other than those that we have studied in depth during this RTR 
review would have significantly greater associated uncertainties than 
the source category or facility-wide estimates. Such aggregate or 
cumulative assessments would compound those uncertainties, making the 
assessments too unreliable.

B. How do we perform the technology review?

    Our technology review focuses on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identify such developments, we analyze their technical feasibility, 
estimated costs, energy implications, and non-air environmental 
impacts. We also consider the emission reductions associated with 
applying each development. This analysis informs our decision of 
whether it is ``necessary'' to revise the emissions standards. In 
addition, we consider the appropriateness of applying controls to new 
sources versus retrofitting existing sources. For this exercise, we 
consider any of the following to be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards;
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT standards) that could result in additional emissions 
reduction;
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards;
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original MACT 
standards; and
     Any significant changes in the cost (including cost 
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original MACT standards).
    In addition to reviewing the practices, processes, and control 
technologies that were considered at the time we originally developed 
the NESHAP, we review a variety of data sources in our investigation of 
potential practices, processes, or controls to consider. See sections 
II.C and II.D of this preamble for information on the specific data 
sources that were reviewed as part of the technology review.

C. How do we estimate post-MACT risk posed by the source category?

    In this section, we provide a complete description of the types of 
analyses that we generally perform during the risk assessment process. 
In some cases, we do not perform a specific analysis because it is not 
relevant. For example, in the absence of emissions of HAP known to be 
persistent and bioaccumulative in the environment (PB-HAP), we would 
not perform a multipathway exposure assessment. Where we do not perform 
an analysis, we state that we do not and provide the reason. While we 
present all of our risk assessment methods, we only present risk 
assessment results for the analyses actually conducted (see section 
IV.A of this preamble).
    The EPA conducts a risk assessment that provides estimates of the 
MIR for cancer posed by the HAP emissions from each source in the 
source category, the HI for chronic exposures to HAP with the potential 
to cause noncancer health effects, and the HQ for acute exposures to 
HAP with the potential to cause noncancer health effects. The 
assessment also provides estimates of the distribution of cancer risk 
within the exposed populations, cancer incidence, and an evaluation of 
the potential for an adverse environmental effect. The seven sections 
that follow this paragraph describe how we estimated emissions and 
conducted the risk assessment. The docket for this rulemaking contains 
the following document which provides more information on the risk 
assessment inputs and models: Residual Risk Assessment for the Taconite 
Iron Ore Processing Source Category in Support of the 2019 Risk and 
Technology Review Proposed Rule (also referred to as the Taconite Risk 
Report in this preamble, and available in Docket ID No. EPA-HQ-OAR-
2017-0664). The methods used to assess risk (as described in the seven 
primary steps below) are consistent with those described by the EPA in 
the document reviewed by a panel of the EPA's SAB in 2009; \4\ and 
described in the SAB review report issued in 2010. They are also 
consistent with the key recommendations contained in that report.
---------------------------------------------------------------------------

    \4\ U.S. EPA. Risk and Technology Review (RTR) Risk Assessment 
Methodologies: For Review by the EPA's Science Advisory Board with 
Case Studies--MACT I Petroleum Refining Sources and Portland Cement 
Manufacturing, June 2009. EPA-452/R-09-006. https://www3.epa.gov/airtoxics/rrisk/rtrpg.html.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    The HAP emissions from taconite iron ore processing plants fall 
into the following pollutant categories: Metals (HAP metals), acid 
gases (i.e., HCl and HF), and combustion-related organic HAP, such as 
polycyclic aromatic hydrocarbons, dioxins/furans (D/F), benzene, and 
formaldehyde. The HAP

[[Page 50667]]

are emitted from several emission sources at taconite iron ore 
processing plants which, for the purposes of the source category risk 
assessment, have been categorized into five emission process groups as 
follows: ore crushing and handling operations, ore drying, pellet 
induration, finished pellet handling operations, and fugitive dust 
emissions control plan sources.
    The main sources of emissions data include the NEI data submitted 
for calendar year 2014 and supplemental information submitted by 
industry (available in Docket ID No. EPA-HQ-OAR-2017-0664). Data on the 
numbers, types, dimensions, and locations of the emission points for 
each facility were obtained from the NEI, state agencies (i.e., the 
Minnesota Pollution Control Agency and the Michigan Department of 
Environmental Quality), Google EarthTM, and from 
representatives of the taconite iron ore processing industry. A 
description of the data, approach, and rationale used to develop actual 
HAP emissions estimates is discussed in more detail in the document, 
Development of the Residual Risk Review Emissions Dataset for the 
Taconite Iron Ore Processing Source Category, which is available in the 
docket (Docket ID No. EPA-HQ-OAR-2017-0664).

2. How did we estimate MACT-allowable emissions?

    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during a specified annual time 
period. These ``actual'' emission levels are often lower than the 
emission levels allowed under the requirements of the current MACT 
standards. The emissions allowed under the MACT standards are referred 
to as the ``MACT-allowable'' emissions. We discussed the consideration 
of both MACT-allowable and actual emissions in the final Coke Oven 
Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the proposed 
and final Hazardous Organic NESHAP RTR (71 FR 34428, June 14, 2006, and 
71 FR 76609, December 21, 2006, respectively). In those actions, we 
noted that assessing the risk at the MACT-allowable level is inherently 
reasonable since that risk reflects the maximum level facilities could 
emit and still comply with national emission standards. We also 
explained that it is reasonable to consider actual emissions, where 
such data are available, in both steps of the risk analysis, in 
accordance with the Benzene NESHAP approach. (54 FR 38044, September 
14, 1989.)
    Allowable emission rates for the taconite iron ore processing 
plants were developed by scaling the actual emission rates. 
Specifically, once the actual emission rates were developed for a given 
facility, the allowable emission rate of each emission process group at 
a given facility was estimated by multiplying the actual emission rate 
of the emission process group by the ratio of the effective (maximum) 
production rate of that facility to the actual production rate of that 
facility during calendar year 2014. The ratios all exceeded 1.0 
resulting in all allowable emissions being greater than actual 
emissions. For a detailed description of the estimation of allowable 
emissions, see the document, Development of the Residual Risk Review 
Emissions Dataset for the Taconite Iron Ore Processing Source Category, 
which is available in the docket (Docket ID No. EPA-HQ-OAR-2017-0664).
3. How do we conduct dispersion modeling, determine inhalation 
exposures, and estimate individual and population inhalation risk?
    Both long-term and short-term inhalation exposure concentrations 
and health risk from the source category addressed in this action were 
estimated using the Human Exposure Model (HEM-3).\5\ The HEM-3 performs 
three primary risk assessment activities: (1) Conducting dispersion 
modeling to estimate the concentrations of HAP in ambient air, (2) 
estimating long-term and short-term inhalation exposures to individuals 
residing within 50 kilometers (km) of the modeled sources, and (3) 
estimating individual and population-level inhalation risk using the 
exposure estimates and quantitative dose-response information.
---------------------------------------------------------------------------

    \5\ For more information about HEM-3, go to https://www.epa.gov/fera/risk-assessment-and-modeling-human-exposure-model-hem.
---------------------------------------------------------------------------

a. Dispersion Modeling
    The air dispersion model AERMOD, used by the HEM-3 model, is one of 
the EPA's preferred models for assessing air pollutant concentrations 
from industrial facilities.\6\ To perform the dispersion modeling and 
to develop the preliminary risk estimates, HEM-3 draws on three data 
libraries. The first is a library of meteorological data, which is used 
for dispersion calculations. This library includes 1 year (2016) of 
hourly surface and upper air observations from 824 meteorological 
stations, selected to provide coverage of the United States and Puerto 
Rico. A second library of United States Census Bureau census block \7\ 
internal point locations and populations provides the basis of human 
exposure calculations (U.S. Census, 2010). In addition, for each census 
block, the census library includes the elevation and controlling hill 
height, which are also used in dispersion calculations. A third library 
of pollutant-specific dose-response values is used to estimate health 
risk. These are discussed below.
---------------------------------------------------------------------------

    \6\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \7\ A census block is the smallest geographic area for which 
census statistics are tabulated.
---------------------------------------------------------------------------

b. Risk From Chronic Exposure to HAP
    In developing the risk assessment for chronic exposures, we use the 
estimated annual average ambient air concentrations of each HAP emitted 
by each source in the source category. The HAP air concentrations at 
each nearby census block centroid located within 50 km of the facility 
are a surrogate for the chronic inhalation exposure concentration for 
all the people who reside in that census block. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044, September 14, 1989) and the limitations of Gaussian 
dispersion models, including AERMOD.
    For each facility, we calculate the MIR as the cancer risk 
associated with a continuous lifetime (24 hours per day, 7 days per 
week, 52 weeks per year, 70 years) exposure to the maximum 
concentration at the centroid of each inhabited census block. We 
calculate individual cancer risk by multiplying the estimated lifetime 
exposure to the ambient concentration of each HAP (in micrograms per 
cubic meter ([mu]g/m\3\)) by its unit risk estimate (URE). The URE is 
an upper-bound estimate of an individual's incremental risk of 
contracting cancer over a lifetime of exposure to a concentration of 1 
microgram of the pollutant per cubic meter of air. For residual risk 
assessments, we generally use UREs from the EPA's Integrated Risk 
Information System (IRIS). For carcinogenic pollutants without IRIS 
values, we look to other reputable sources of cancer dose-response 
values, often using California EPA (CalEPA) UREs, where available. In 
cases where new, scientifically credible dose-response values have been 
developed in a manner consistent with EPA guidelines and have undergone 
a peer review process similar to that used by the EPA, we may use such 
dose-response values in place of, or in addition to, other values, if 
appropriate. The pollutant-specific dose-response

[[Page 50668]]

values used to estimate health risk are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
    To estimate individual lifetime cancer risks associated with 
exposure to HAP emissions from each facility in the source category, we 
sum the risks for each of the carcinogenic HAP \8\ emitted by the 
modeled facility. We estimate cancer risk at every census block within 
50 km of every facility in the source category. The MIR is the highest 
individual lifetime cancer risk estimated for any of those census 
blocks. In addition to calculating the MIR, we estimate the 
distribution of individual cancer risks for the source category by 
summing the number of individuals within 50 km of the sources whose 
estimated risk falls within a specified risk range. We also estimate 
annual cancer incidence by multiplying the estimated lifetime cancer 
risk at each census block by the number of people residing in that 
block, summing results for all of the census blocks, and then dividing 
this result by a 70-year lifetime.
---------------------------------------------------------------------------

    \8\ The EPA's 2005 Guidelines for Carcinogen Risk Assessment 
classifies carcinogens as: ``carcinogenic to humans,'' ``likely to 
be carcinogenic to humans,'' and ``suggestive evidence of 
carcinogenic potential.'' These classifications also coincide with 
the terms ``known carcinogen, probable carcinogen, and possible 
carcinogen,'' respectively, which are the terms advocated in the 
EPA's Guidelines for Carcinogen Risk Assessment, published in 1986 
(51 FR 33992, September 24, 1986). In August 2000, the document, 
Supplemental Guidance for Conducting Health Risk Assessment of 
Chemical Mixtures (EPA/630/R-00/002), was published as a supplement 
to the 1986 document. Copies of both documents can be obtained from 
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing 
the risk of these individual compounds to obtain the cumulative 
cancer risk is an approach that was recommended by the EPA's SAB in 
their 2002 peer review of the EPA's National Air Toxics Assessment 
(NATA) titled NATA--Evaluating the National-scale Air Toxics 
Assessment 1996 Data--an SAB Advisory, available at https://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of noncancer health effects from chronic 
exposure to HAP, we calculate either an HQ or a target organ-specific 
hazard index (TOSHI). We calculate an HQ when a single noncancer HAP is 
emitted. Where more than one noncancer HAP is emitted, we sum the HQ 
for each of the HAP that affects a common target organ or target organ 
system to obtain a TOSHI. The HQ is the estimated exposure divided by 
the chronic noncancer dose-response value, which is a value selected 
from one of several sources. The preferred chronic noncancer dose-
response value is the EPA RfC, defined as ``an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure to the human population (including sensitive 
subgroups) that is likely to be without an appreciable risk of 
deleterious effects during a lifetime'' (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary). In cases where an RfC 
from the EPA's IRIS is not available or where the EPA determines that 
using a value other than the RfC is appropriate, the chronic noncancer 
dose-response value can be a value from the following prioritized 
sources, which define their dose-response values similarly to the EPA: 
(1) The Agency for Toxic Substances and Disease Registry (ATSDR) 
Minimum Risk Level (https://www.atsdr.cdc.gov/mrls/index.asp); (2) the 
CalEPA Chronic Reference Exposure Level (REL) (https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0); or (3) as noted above, a scientifically 
credible dose-response value that has been developed in a manner 
consistent with the EPA guidelines and has undergone a peer review 
process similar to that used by the EPA. The pollutant-specific dose-
response values used to estimate health risks are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
c. Risk From Acute Exposure to HAP That May Cause Health Effects Other 
Than Cancer
    For each HAP for which appropriate acute inhalation dose-response 
values are available, the EPA also assesses the potential health risks 
due to acute exposure. For these assessments, the EPA makes 
conservative assumptions about emission rates, meteorology, and 
exposure location. In this proposed rulemaking, as part of our efforts 
to continually improve our methodologies to evaluate the risks that HAP 
emitted from categories of industrial sources pose to human health and 
the environment,\9\ we are revising our treatment of meteorological 
data to use reasonable worst-case air dispersion conditions in our 
acute risk screening assessments instead of worst-case air dispersion 
conditions. This revised treatment of meteorological data and the 
supporting rationale are described in more detail in Residual Risk 
Assessment for Taconite Iron Ore Processing Source Category in Support 
of the 2019 Risk and Technology Review Proposed Rule and in Appendix 5 
of the report: Technical Support Document for Acute Risk Screening 
Assessment. We will be applying this revision in RTR rulemakings 
proposed on or after June 3, 2019.
---------------------------------------------------------------------------

    \9\ See, e.g., U.S. EPA. Screening Methodologies to Support Risk 
and Technology Reviews (RTR): A Case Study Analysis (Draft Report, 
May 2017. https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html).
---------------------------------------------------------------------------

    To assess the potential acute risk to the maximally exposed 
individual, we use the peak hourly emission rate for each emission 
point,\10\ reasonable worst-case air dispersion conditions (i.e., 99th 
percentile), and the point of highest off-site exposure. Specifically, 
we assume that peak emissions from the source category and reasonable 
worst-case air dispersion conditions co-occur and that a person is 
present at the point of maximum exposure.
---------------------------------------------------------------------------

    \10\ In the absence of hourly emission data, we develop 
estimates of maximum hourly emission rates by multiplying the 
average actual annual emissions rates by a factor (either a 
category-specific factor or a default factor of 10) to account for 
variability. This is documented in Residual Risk Assessment for 
Taconite Iron Ore Processing Source Category in Support of the 2019 
Risk and Technology Review Proposed Rule and in Appendix 5 of the 
report: Technical Support Document for Acute Risk Screening 
Assessment. Both are available in the docket for this rulemaking.
---------------------------------------------------------------------------

    To characterize the potential health risks associated with 
estimated acute inhalation exposures to a HAP, we generally use 
multiple acute dose-response values, including acute RELs, acute 
exposure guideline levels (AEGLs), and emergency response planning 
guidelines (ERPG) for 1-hour exposure durations, if available, to 
calculate acute HQs. The acute HQ is calculated by dividing the 
estimated acute exposure concentration by the acute dose-response 
value. For each HAP for which acute dose-response values are available, 
the EPA calculates acute HQs.
    An acute REL is defined as ``the concentration level at or below 
which no adverse health effects are anticipated for a specified 
exposure duration.'' \11\ Acute RELs are based on the most sensitive, 
relevant, adverse health effect reported in the peer-reviewed medical 
and toxicological literature. They are designed to protect the most 
sensitive individuals in the population through the inclusion of 
margins of safety. Because margins of safety are incorporated to 
address data gaps and

[[Page 50669]]

uncertainties, exceeding the REL does not automatically indicate an 
adverse health impact. AEGLs represent threshold exposure limits for 
the general public and are applicable to emergency exposures ranging 
from 10 minutes to 8 hours.\12\ They are guideline levels for ``once-
in-a-lifetime, short-term exposures to airborne concentrations of 
acutely toxic, high-priority chemicals.'' Id. at 21. The AEGL-1 is 
specifically defined as ``the airborne concentration (expressed as ppm 
(parts per million) or mg/m\3\ (milligrams per cubic meter)) of a 
substance above which it is predicted that the general population, 
including susceptible individuals, could experience notable discomfort, 
irritation, or certain asymptomatic nonsensory effects. However, the 
effects are not disabling and are transient and reversible upon 
cessation of exposure.'' The document also notes that ``Airborne 
concentrations below AEGL-1 represent exposure levels that can produce 
mild and progressively increasing but transient and nondisabling odor, 
taste, and sensory irritation or certain asymptomatic, nonsensory 
effects.'' Id. AEGL-2 are defined as ``the airborne concentration 
(expressed as parts per million or milligrams per cubic meter) of a 
substance above which it is predicted that the general population, 
including susceptible individuals, could experience irreversible or 
other serious, long-lasting adverse health effects or an impaired 
ability to escape.'' Id.
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    \11\ CalEPA issues acute RELs as part of its Air Toxics Hot 
Spots Program, and the 1-hour and 8-hour values are documented in 
Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The 
Determination of Acute Reference Exposure Levels for Airborne 
Toxicants, which is available at https://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
    \12\ National Academy of Sciences, 2001. Standing Operating 
Procedures for Developing Acute Exposure Levels for Hazardous 
Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.pdf. Note that the 
National Advisory Committee for Acute Exposure Guideline Levels for 
Hazardous Substances ended in October 2011, but the AEGL program 
continues to operate at the EPA and works with the National 
Academies to publish final AEGLs (https://www.epa.gov/aegl).
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    ERPGs are ``developed for emergency planning and are intended as 
health-based guideline concentrations for single exposures to 
chemicals.'' \13\ Id. at 1. The ERPG-1 is defined as ``the maximum 
airborne concentration below which it is believed that nearly all 
individuals could be exposed for up to 1 hour without experiencing 
other than mild transient adverse health effects or without perceiving 
a clearly defined, objectionable odor.'' Id. at 2. Similarly, the ERPG-
2 is defined as ``the maximum airborne concentration below which it is 
believed that nearly all individuals could be exposed for up to one 
hour without experiencing or developing irreversible or other serious 
health effects or symptoms which could impair an individual's ability 
to take protective action.'' Id. at 1.
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    \13\ ERPGS Procedures and Responsibilities. March 2014. American 
Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf.
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    An acute REL for 1-hour exposure durations is typically lower than 
its corresponding AEGL-1 and ERPG-1. Even though their definitions are 
slightly different, AEGL-1s are often the same as the corresponding 
ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from 
our acute inhalation screening risk assessment typically result when we 
use the acute REL for a HAP. In cases where the maximum acute HQ 
exceeds 1, we also report the HQ based on the next highest acute dose-
response value (usually the AEGL-1 and/or the ERPG-1).
    For this source category, ore crushing and handling, ore drying, 
and pellet handling operations may have batch operation cycles with 
peak emissions as high as 10 times the average hourly actual emissions 
occurring for part of that cycle. Therefore, a factor of 10 was used to 
estimate peak hourly emissions for these sources. With regard to 
fugitive dust emissions (e.g., stockpiles, material transfer points, 
plant roadways, tailings basin, pellet loading areas, and yard areas), 
we assumed peak hourly emissions could be as high as 10 times the 
average (i.e., the default value described in footnote number 10) 
because we did not have sufficient data or information to derive a 
different value. However, with regard to indurating furnaces, which 
typically operate continuously for long periods of time with relatively 
minor fluctuations, it is estimated that emission rates could 
occasionally increase by a factor of up to two times the average hourly 
actual emission. Therefore, the EPA selected two as the appropriate 
multiplier to estimate maximum acute emissions from indurating 
furnaces. A more detailed discussion of the selection of the acute 
emission factors is available in the document Development of the 
Residual Risk Review Emissions Dataset for the Taconite Iron Ore 
Processing Source Category, available in the docket (Docket ID No. EPA-
HQ-OAR-2017-0664).
    In our acute inhalation screening risk assessment, acute impacts 
are deemed negligible for HAP for which acute HQs are less than or 
equal to 1, and no further analysis is performed for these HAP. In 
cases where an acute HQ from the screening analysis is greater than 1, 
we assess the site-specific data to ensure that the acute HQ is at an 
off-site location. For this source category, for each HAP with an acute 
HQ value greater than 1, the data refinements employed consisted of 
plotting the HEM-3 polar grid results on aerial photographs of the 
facilities. We then assessed whether the highest acute HQs were off-
site and at locations that may be accessible to the public (e.g., 
roadways and public buildings). These refinements are discussed more 
fully in the Taconite Risk Report, which is available in the docket for 
this source category.
4. How do we conduct the multipathway exposure and risk screening 
assessment?
    The EPA conducts a tiered screening assessment examining the 
potential for significant human health risks due to exposures via 
routes other than inhalation (i.e., ingestion). We first determine 
whether any sources in the source category emit any HAP known to be 
persistent and bioaccumulative in the environment, as identified in the 
EPA's Air Toxics Risk Assessment Library (see Volume 1, Appendix D, at 
https://www.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library.
    For the Taconite Iron Ore Processing source category, we identified 
PB-HAP emissions of arsenic, cadmium, D/F, lead, mercury, and 
polycyclic organic matter (POM), so we proceeded to the next step of 
the evaluation. Except for lead, the human health risk screening 
assessment for PB-HAP consists of three progressive tiers. In a Tier 1 
screening assessment, we determine whether the magnitude of the 
facility-specific emissions of PB-HAP warrants further evaluation to 
characterize human health risk through ingestion exposure. To 
facilitate this step, we evaluate emissions against previously 
developed screening threshold emission rates for several PB-HAP that 
are based on a hypothetical upper-end screening exposure scenario 
developed for use in conjunction with the EPA's Total Risk Integrated 
Methodology. Fate, Transport, and Ecological Exposure (TRIM.FaTE) 
model. The PB-HAP with screening threshold emission rates are arsenic 
compounds, cadmium compounds, chlorinated dibenzodioxins and furans, 
mercury compounds, and POM. Based on the EPA estimates of toxicity and 
bioaccumulation potential, these pollutants represent a conservative 
list for inclusion in multipathway risk assessments for RTR rules. (See 
Volume 1, Appendix D at https://www.epa.gov/sites/production/files/2013-08/documents/volume_1_reflibrary.pdf.) In this assessment, we

[[Page 50670]]

compare the facility-specific emission rates of these PB-HAP to the 
screening threshold emission rates for each PB-HAP to assess the 
potential for significant human health risks via the ingestion pathway. 
The ratio of a facility's actual emission rate to the Tier 1 screening 
threshold emission rate is a ``screening value.''
    We derive the Tier 1 screening threshold emission rates for these 
PB-HAP (other than lead compounds) to correspond to a maximum excess 
lifetime cancer risk of 1-in-1 million (i.e., for arsenic compounds, 
polychlorinated dibenzodioxins and furans and POM) or, for HAP that 
cause noncancer health effects (i.e., cadmium compounds and mercury 
compounds), a maximum HQ of 1. If the emission rate of any one PB-HAP 
or combination of carcinogenic PB-HAP in the Tier 1 screening 
assessment exceeds the Tier 1 screening threshold emission rate for any 
facility (i.e., the screening value is greater than 1), we conduct a 
second screening assessment, which we call the Tier 2 screening 
assessment. The Tier 2 screening assessment separates the Tier 1 
combined fisher and farmer exposure scenario into fisher, farmer, and 
gardener scenarios that retain upper-bound ingestion rates.
    In the Tier 2 screening assessment, the location of each facility 
that exceeds a Tier 1 screening threshold emission rate is used to 
refine the assumptions associated with the Tier 1 fisher and farmer 
exposure scenarios at that facility. A key assumption in the Tier 1 
screening assessment is that a lake and/or farm is located near the 
facility. As part of the Tier 2 screening assessment, we use a U.S. 
Geological Survey (USGS) database to identify actual waterbodies within 
50 km of each facility and assume the fisher only consumes fish from 
lakes within that 50 km zone. We also examine the differences between 
local meteorology near the facility and the meteorology used in the 
Tier 1 screening assessment. We then adjust the previously-developed 
Tier 1 screening threshold emission rates for each PB-HAP for each 
facility based on an understanding of how exposure concentrations 
estimated for the screening scenario change with the use of local 
meteorology and USGS lakes database.
    In the Tier 2 farmer scenario, we maintain an assumption that the 
farm is located within 0.5 km of the facility and that the farmer 
consumes meat, eggs, dairy, vegetables, and fruit produced near the 
facility. We may further refine the Tier 2 screening analysis by 
assessing a gardener scenario to characterize a range of exposures, 
with the gardener scenario being more plausible in RTR evaluations. 
Under the gardener scenario, we assume the gardener consumes home-
produced eggs, vegetables, and fruit products at the same ingestion 
rate as the farmer. The Tier 2 screen continues to rely on the high-end 
food intake assumptions that were applied in Tier 1 for local fish 
(adult female angler at 99th percentile fish consumption), \14\ and 
locally grown or raised foods (90th percentile consumption of locally 
grown or raised foods for the farmer and gardener scenarios).\15\ If 
PB-HAP emission rates do not result in a Tier 2 screening value greater 
than 1, we consider those PB-HAP emissions to pose risks below a level 
of concern. If the PB-HAP emission rates for a facility exceed the Tier 
2 screening threshold emission rates, we may conduct a Tier 3 screening 
assessment.
---------------------------------------------------------------------------

    \14\ Burger, J. 2002. Daily consumption of wild fish and game: 
Exposures of high end recreationists. International Journal of 
Environmental Health Research 12:343-354.
    \15\ U.S. EPA. Exposure Factors Handbook 2011 Edition (Final). 
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/
052F, 2011.
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    There are several analyses that can be included in a Tier 3 
screening assessment, depending upon the extent of refinement 
warranted, including validating that the lakes are fishable, locating 
residential/garden locations for urban and/or rural settings, 
considering plume-rise to estimate emissions lost above the mixing 
layer, and considering hourly effects of meteorology and plume-rise on 
chemical fate and transport (a time-series analysis). If necessary, the 
EPA may further refine the screening assessment through a site-specific 
assessment.
    There are several analyses that can be included in a Tier 3 
screening assessment, depending upon the extent of refinement 
warranted, including validating that the lakes are fishable, locating 
residential/garden locations for urban and/or rural settings, 
considering plume-rise to estimate emissions lost above the mixing 
layer, and considering hourly effects of meteorology and plume rise on 
chemical fate and transport (a time-series analysis). If necessary, the 
EPA may further refine the screening assessment through a site-specific 
assessment.
    In evaluating the potential multipathway risk from emissions of 
lead compounds, rather than developing a screening threshold emission 
rate, we compare maximum estimated chronic inhalation exposure 
concentrations to the level of the current National Ambient Air Quality 
Standard (NAAQS) for lead.\16\ Values below the level of the primary 
(health-based) lead NAAQS are considered to have a low potential for 
multipathway risk.
---------------------------------------------------------------------------

    \16\ In doing so, the EPA notes that the legal standard for a 
primary NAAQS--that a standard is requisite to protect public health 
and provide an adequate margin of safety (CAA section 109(b))--
differs from the CAA section 112(f) standard (requiring, among other 
things, that the standard provide an ``ample margin of safety to 
protect public health''). However, the primary lead NAAQS is a 
reasonable measure of determining risk acceptability (i.e., the 
first step of the Benzene NESHAP analysis) since it is designed to 
protect the most susceptible group in the human population--
children, including children living near major lead emitting 
sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. In addition, 
applying the level of the primary lead NAAQS at the risk 
acceptability step is conservative, since that primary lead NAAQS 
reflects an adequate margin of safety.
---------------------------------------------------------------------------

    For further information on the multipathway assessment approach, 
see the Taconite Risk Report, which is available in the docket for this 
action.
5. How do we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect, Environmental HAP, and Ecological 
Benchmarks
    The EPA conducts a screening assessment to examine the potential 
for an adverse environmental effect as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
    The EPA focuses on eight HAP, which are referred to as 
``environmental HAP,'' in its screening assessment: Six PB-HAP and two 
acid gases. The PB-HAP included in the screening assessment are arsenic 
compounds, cadmium compounds, D/F, POM, mercury (both inorganic mercury 
and methyl mercury), and lead compounds. The acid gases included in the 
screening assessment are HCl and HF.
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment, and water. The 
acid gases, HCl and HF, are included due to their well-documented 
potential to cause direct damage to terrestrial plants. In the 
environmental risk screening assessment, we evaluate the following four 
exposure media: Terrestrial soils, surface water bodies (includes 
water-column and benthic sediments), fish

[[Page 50671]]

consumed by wildlife, and air. Within these four exposure media, we 
evaluate nine ecological assessment endpoints, which are defined by the 
ecological entity and its attributes. For PB-HAP (other than lead), 
both community-level and population-level endpoints are included. For 
acid gases, the ecological assessment evaluated is terrestrial plant 
communities.
    An ecological benchmark represents a concentration of HAP that has 
been linked to a particular environmental effect level. For each 
environmental HAP, we identified the available ecological benchmarks 
for each assessment endpoint. We identified, where possible, ecological 
benchmarks at the following effect levels: Probable effect levels, 
lowest-observed-adverse-effect level, and no-observed-adverse-effect 
level. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we use all of the available 
effect levels to help us to determine whether ecological risks exist 
and, if so, whether the risks could be considered significant and 
widespread.
    For further information on how the environmental risk screening 
assessment was conducted, including a discussion of the risk metrics 
used, how the environmental HAP were identified, and how the ecological 
benchmarks were selected, see Appendix 9 of the Taconite Risk Report, 
which is available in Docket ID No. EPA-HQ-OAR-2017-0664.
b. Environmental Risk Screening Methodology
    For the environmental risk screening assessment, the EPA first 
determined whether any facilities in the Taconite Iron Ore Processing 
source category emitted any of the environmental HAP. For the Taconite 
Iron Ore Processing source category, we identified emissions of 
arsenic, cadmium, D/F, HCl, HF, lead, mercury, and POM. Because one or 
more of the environmental HAP evaluated are emitted by at least one 
facility in the source category, we proceeded to the second step of the 
evaluation.
c. PB-HAP Methodology
    The environmental screening assessment includes six PB-HAP, arsenic 
compounds, cadmium compounds, D/F, POM, mercury (both inorganic mercury 
and methyl mercury), and lead compounds. With the exception of lead, 
the environmental risk screening assessment for PB-HAP consists of 
three tiers. The first tier of the environmental risk screening 
assessment uses the same health-protective conceptual model that is 
used for the Tier 1 human health screening assessment. TRIM.FaTE 
simulations were used to back-calculate Tier 1 screening threshold 
emission rates. The screening threshold emission rates represent the 
emission rate in tons of pollutant per year that results in media 
concentrations at the facility that equal the relevant ecological 
benchmark. To assess emissions from each facility in the category, the 
reported emission rate for each PB-HAP was compared to the Tier 1 
screening threshold emission rate for that PB-HAP for each assessment 
endpoint and effect level. If emissions from a facility do not exceed 
the Tier 1 screening threshold emission rate, the facility ``passes'' 
the screening assessment, and, therefore, is not evaluated further 
under the screening approach. If emissions from a facility exceed the 
Tier 1 screening threshold emission rate, we evaluate the facility 
further in Tier 2.
    In Tier 2 of the environmental screening assessment, the screening 
threshold emission rates are adjusted to account for local meteorology 
and the actual location of lakes in the vicinity of facilities that did 
not pass the Tier 1 screening assessment. For soils, we evaluate the 
average soil concentration for all soil parcels within a 7.5-km radius 
for each facility and PB-HAP. For the water, sediment, and fish tissue 
concentrations, the highest value for each facility for each pollutant 
is used. If emission concentrations from a facility do not exceed the 
Tier 2 screening threshold emission rate, the facility ``passes'' the 
screening assessment and typically is not evaluated further. If 
emissions from a facility exceed the Tier 2 screening threshold 
emission rate, we evaluate the facility further in Tier 3.
    As in the multipathway human health risk assessment, in Tier 3 of 
the environmental screening assessment, we examine the suitability of 
the lakes around the facilities to support life and remove those that 
are not suitable (e.g., lakes that have been filled in or are 
industrial ponds), adjust emissions for plume-rise, and conduct hour-
by-hour time-series assessments. If these Tier 3 adjustments to the 
screening threshold emission rates still indicate the potential for an 
adverse environmental effect (i.e., facility emission rate exceeds the 
screening threshold emission rate), we may elect to conduct a more 
refined assessment using more site-specific information. If, after 
additional refinement, the facility emission rate still exceeds the 
screening threshold emission rate, the facility may have the potential 
to cause an adverse environmental effect.
    To evaluate the potential for an adverse environmental effect from 
lead, we compared the average modeled air concentrations (from HEM-3) 
of lead around each facility in the source category to the level of the 
secondary NAAQS for lead. The secondary lead NAAQS is a reasonable 
means of evaluating environmental risk because it is set to provide 
substantial protection against adverse welfare effects which can 
include ``effects on soils, water, crops, vegetation, man-made 
materials, animals, wildlife, weather, visibility and climate, damage 
to and deterioration of property, and hazards to transportation, as 
well as effects on economic values and on personal comfort and well-
being.''
d. Acid Gas Environmental Risk Methodology
    The environmental screening assessment for acid gases evaluates the 
potential phytotoxicity and reduced productivity of plants due to 
chronic exposure to HF and HCl. The environmental risk screening 
methodology for acid gases is a single-tier screening assessment that 
compares modeled ambient air concentrations (from AERMOD) to the 
ecological benchmarks for each acid gas. To identify a potential 
adverse environmental effect (as defined in section 112(a)(7) of the 
CAA) from emissions of HF and HCl, we evaluate the following metrics: 
The size of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas, in acres and km\2\; the 
percentage of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas; and the area-weighted average 
screening value around each facility (calculated by dividing the area-
weighted average concentration over the 50-km modeling domain by the 
ecological benchmark for each acid gas). For further information on the 
environmental screening assessment approach, see Appendix 9 of the 
Taconite Risk Report, which is available in Docket ID No. EPA-HQ-OAR-
2017-0664.
6. How do we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category emission points of interest, but also emissions of

[[Page 50672]]

HAP from all other emission sources at the facility for which we have 
data. For this source category, we conducted the facility-wide 
assessment using a dataset compiled from the 2014 NEI and supplemental 
information submitted by industry. The source category records of that 
dataset were evaluated and updated as described in section II.D of this 
preamble. Once a quality assured source category dataset was available, 
it was placed back with the remaining records from the NEI for that 
facility. The facility-wide file was then used to analyze risks due to 
the inhalation of HAP that are emitted ``facility-wide'' for the 
populations residing within 50 km of each facility, consistent with the 
methods used for the source category analysis described above. For 
these facility-wide risk analyses, the modeled source category risks 
were compared to the facility-wide risks to determine the portion of 
the facility-wide risks that could be attributed to the source category 
addressed in this action. We also specifically examined the facility 
that was associated with the highest estimate of risk and determined 
the percentage of that risk attributable to the source category of 
interest. The Taconite Risk Report, available in Docket ID No. EPA-HQ-
OAR-2017-0664, provides the methodology and results of the facility-
wide analyses, including all facility-wide risks and the percentage of 
source category contribution to facility-wide risks.
7. How do we consider uncertainties in risk assessment?
    Uncertainty and the potential for bias are inherent in all risk 
assessments, including those performed for this proposal. Although 
uncertainty exists, we believe that our approach, which used 
conservative tools and assumptions, ensures that our decisions are 
health and environmentally protective. A brief discussion of the 
uncertainties in the RTR emissions dataset, dispersion modeling, 
inhalation exposure estimates, and dose-response relationships follows 
below. Also included are those uncertainties specific to our acute 
screening assessments, multipathway screening assessments, and our 
environmental risk screening assessments. A more thorough discussion of 
these uncertainties is included in the Taconite Risk Report, which is 
available in the docket for this action. If a multipathway site-
specific assessment was performed for this source category, a full 
discussion of the uncertainties associated with that assessment can be 
found in Appendix 11 of that document, Site-Specific Human Health 
Multipathway Residual Risk Assessment Report.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control (QA/QC) processes, the accuracy of 
emissions values will vary depending on the source of the data, the 
degree to which data are incomplete or missing, the degree to which 
assumptions made to complete the datasets are accurate, errors in 
emission estimates, and other factors. The emission estimates 
considered in this analysis generally are annual totals for certain 
years, and they do not reflect short-term fluctuations during the 
course of a year or variations from year to year. The estimates of peak 
hourly emission rates for the acute effects screening assessment were 
based on an emission adjustment factor applied to the average annual 
hourly emission rates, which are intended to account for emission 
fluctuations due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to estimate 
ambient pollutant concentrations, the user chooses certain options to 
apply. For RTR assessments, we select some model options that have the 
potential to overestimate ambient air concentrations (e.g., not 
including plume depletion or pollutant transformation). We select other 
model options that have the potential to underestimate ambient impacts 
(e.g., not including building downwash). Other options that we select 
have the potential to either under- or overestimate ambient levels 
(e.g., meteorology and receptor locations). On balance, considering the 
directional nature of the uncertainties commonly present in ambient 
concentrations estimated by dispersion models, the approach we apply in 
the RTR assessments should yield unbiased estimates of ambient HAP 
concentrations. We also note that the selection of meteorology dataset 
location could have an impact on the risk estimates. As we continue to 
update and expand our library of meteorological station data used in 
our risk assessments, we expect to reduce this variability.
c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant 
facilities and emission points, as well as to develop accurate 
estimates of the annual emission rates for all relevant HAP, the 
uncertainties in our emission inventory likely dominate the 
uncertainties in the exposure assessment. Some uncertainties in our 
exposure assessment include human mobility, using the centroid of each 
census block, assuming lifetime exposure, and assuming only outdoor 
exposures. For most of these factors, there is neither an under- nor 
overestimate when looking at the maximum individual risk or the 
incidence, but the shape of the distribution of risks may be affected. 
With respect to outdoor exposures, actual exposures may not be as high 
if people spend time indoors, especially for very reactive pollutants 
or larger particles. For all factors, we reduce uncertainty when 
possible. For example, with respect to census-block centroids, we 
analyze large blocks using aerial imagery and adjust locations of the 
block centroids to better represent the population in the blocks. We 
also add additional receptor locations where the population of a block 
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and noncancer effects from both chronic and acute 
exposures. Some uncertainties are generally expressed quantitatively, 
and others are generally expressed in qualitative terms. We note, as a 
preface to this discussion, a point on dose-response uncertainty that 
is stated in the EPA's 2005 Guidelines for Carcinogen Risk Assessment; 
namely, that ``the primary goal of EPA actions is protection of human 
health; accordingly, as an Agency policy, risk assessment procedures, 
including default options that are used in the absence of scientific 
data to the contrary, should be health protective'' (the EPA's 2005 
Guidelines for Carcinogen Risk Assessment, page 1-7). This is the 
approach followed here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been 
developed to generally provide an upper bound estimate of risk.\17\ 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical

[[Page 50673]]

confidence limit). In some circumstances, the true risk could be as low 
as zero; however, in other circumstances the risk could be greater.\18\ 
Chronic noncancer RfC and reference dose (RfD) values represent chronic 
exposure levels that are intended to be health-protective levels. To 
derive dose-response values that are intended to be ``without 
appreciable risk,'' the methodology relies upon an uncertainty factor 
(UF) approach,\19\ which considers uncertainty, variability, and gaps 
in the available data. The UFs are applied to derive dose-response 
values that are intended to protect against appreciable risk of 
deleterious effects.
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    \17\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \18\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible, and which is based on maximum 
likelihood estimates.
    \19\ See A Review of the Reference Dose and Reference 
Concentration Processes, U.S. EPA, December 2002, and Methods for 
Derivation of Inhalation Reference Concentrations and Application of 
Inhalation Dosimetry, U.S. EPA, 1994.
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    Many of the UFs used to account for variability and uncertainty in 
the development of acute dose-response values are quite similar to 
those developed for chronic durations. Additional adjustments are often 
applied to account for uncertainty in extrapolation from observations 
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all 
acute dose-response values are developed for the same purpose, and care 
must be taken when interpreting the results of an acute assessment of 
human health effects relative to the dose-response value or values 
being exceeded. Where relevant to the estimated exposures, the lack of 
acute dose-response values at different levels of severity should be 
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks 
for the environmental risk screening assessment. We established a 
hierarchy of preferred benchmark sources to allow selection of 
benchmarks for each environmental HAP at each ecological assessment 
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but 
not all combinations of ecological assessment/environmental HAP had 
benchmarks for all three effect levels. Where multiple effect levels 
were available for a particular HAP and assessment endpoint, we used 
all of the available effect levels to help us determine whether risk 
exists and whether the risk could be considered significant and 
widespread.
    Although we make every effort to identify appropriate human health 
effect dose-response values for all pollutants emitted by the sources 
in this risk assessment, some HAP emitted by this source category are 
lacking dose-response assessments. Accordingly, these pollutants cannot 
be included in the quantitative risk assessment, which could result in 
quantitative estimates understating HAP risk. To help to alleviate this 
potential underestimate, where we conclude similarity with a HAP for 
which a dose-response value is available, we use that value as a 
surrogate for the assessment of the HAP for which no value is 
available. To the extent use of surrogates indicates appreciable risk, 
we may identify a need to increase priority for an IRIS assessment for 
that substance. We additionally note that, generally speaking, HAP of 
greatest concern due to environmental exposures and hazard are those 
for which dose-response assessments have been performed, reducing the 
likelihood of understating risk. Further, HAP not included in the 
quantitative assessment are assessed qualitatively and considered in 
the risk characterization that informs the risk management decisions, 
including consideration of HAP reductions achieved by various control 
options.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective dose-response value 
of an individual compound in that group to estimate risk. Similarly, 
for an individual compound in a group (e.g., ethylene glycol diethyl 
ether) that does not have a specified dose-response value, we also 
apply the most protective dose-response value from the other compounds 
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA. The 
accuracy of an acute inhalation exposure assessment depends on the 
simultaneous occurrence of independent factors that may vary greatly, 
such as hourly emission rates, meteorology, and the presence of a 
person. In the acute screening assessment that we conduct under the RTR 
program, we assume that peak emissions from the source category and 
reasonable worst-case air dispersion conditions (i.e., 99th percentile) 
co-occur. We then include the additional assumption that a person is 
located at this point at the same time. Together, these assumptions 
represent a reasonable worst-case exposure scenario. In most cases, it 
is unlikely that a person would be located at the point of maximum 
exposure during the time when peak emissions and reasonable worst-case 
air dispersion conditions occur simultaneously.
f. Uncertainties in the Multipathway and Environmental Risk Screening 
Assessments
    For each source category, we generally rely on site-specific levels 
of PB-HAP or environmental HAP emissions to determine whether a refined 
assessment of the impacts from multipathway exposures is necessary or 
whether it is necessary to perform an environmental screening 
assessment. This determination is based on the results of a three-
tiered screening assessment that relies on the outputs from models--
TRIM.FaTE and AERMOD--that estimate environmental pollutant 
concentrations and human exposures for five PB-HAP (dioxins, POM, 
mercury, cadmium, and arsenic) and two acid gases (HF and HCl). For 
lead, we use AERMOD to determine ambient air concentrations, which are 
then compared to the secondary NAAQS standard for lead. Two important 
types of uncertainty associated with the use of these models in RTR 
risk assessments and inherent to any assessment that relies on 
environmental modeling are model uncertainty and input uncertainty.\20\
---------------------------------------------------------------------------

    \20\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the model adequately represents 
the actual processes (e.g., movement and accumulation) that might occur 
in the environment. For example, does the model adequately describe the 
movement of a pollutant through the soil? This type of uncertainty is 
difficult to quantify. However, based on feedback received from 
previous EPA SAB reviews and other reviews, we are confident that the 
models used in the screening assessments are appropriate and state-of-
the-art for the multipathway and environmental screening risk 
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the

[[Page 50674]]

assessment at hand. For Tier 1 of the multipathway and environmental 
screening assessments, we configured the models to avoid 
underestimating exposure and risk. This was accomplished by selecting 
upper-end values from nationally representative datasets for the more 
influential parameters in the environmental model, including selection 
and spatial configuration of the area of interest, lake location and 
size, meteorology, surface water, soil characteristics, and structure 
of the aquatic food web. We also assume an ingestion exposure scenario 
and values for human exposure factors that represent reasonable maximum 
exposures.
    In Tier 2 of the multipathway and environmental screening 
assessments, we refine the model inputs to account for meteorological 
patterns in the vicinity of the facility versus using upper-end 
national values, and we identify the actual location of lakes near the 
facility rather than the default lake location that we apply in Tier 1. 
By refining the screening approach in Tier 2 to account for local 
geographical and meteorological data, we decrease the likelihood that 
concentrations in environmental media are overestimated, thereby 
increasing the usefulness of the screening assessment. In Tier 3 of the 
screening assessments, we refine the model inputs again to account for 
hour-by-hour plume-rise and the height of the mixing layer. We can also 
use those hour-by-hour meteorological data in a TRIM.FaTE run using the 
screening configuration corresponding to the lake location. These 
refinements produce a more accurate estimate of chemical concentrations 
in the media of interest, thereby reducing the uncertainty with those 
estimates. The assumptions and the associated uncertainties regarding 
the selected ingestion exposure scenario are the same for all three 
tiers.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For all tiers of the multipathway and environmental screening 
assessments, our approach to addressing model input uncertainty is 
generally cautious. We choose model inputs from the upper end of the 
range of possible values for the influential parameters used in the 
models, and we assume that the exposed individual exhibits ingestion 
behavior that would lead to a high total exposure. This approach 
reduces the likelihood of not identifying high risks for adverse 
impacts.
    Despite the uncertainties, when individual pollutants or facilities 
do not exceed screening threshold emission rates (i.e., screen out), we 
are confident that the potential for adverse multipathway impacts on 
human health is very low. On the other hand, when individual pollutants 
or facilities do exceed screening threshold emission rates, it does not 
mean that impacts are significant, only that we cannot rule out that 
possibility and that a refined assessment for the site might be 
necessary to obtain a more accurate risk characterization for the 
source category.
    The EPA evaluates the following HAP in the multipathway and/or 
environmental risk screening assessments, where applicable: arsenic, 
cadmium, D/F, lead, mercury (both inorganic and methyl mercury), POM, 
HCl, and HF. These HAP represent pollutants that can cause adverse 
impacts either through direct exposure to HAP in the air or through 
exposure to HAP that are deposited from the air onto soils and surface 
waters and then through the environment into the food web. These HAP 
represent those HAP for which we can conduct a meaningful multipathway 
or environmental screening risk assessment. For other HAP not included 
in our screening assessments, the model has not been parameterized such 
that it can be used for that purpose. In some cases, depending on the 
HAP, we may not have appropriate multipathway models that allow us to 
predict the concentration of that pollutant. The EPA acknowledges that 
other HAP beyond these that we are evaluating may have the potential to 
cause adverse effects and, therefore, the EPA may evaluate other 
relevant HAP in the future, as modeling science and resources allow.

IV. Analytical Results and Proposed Decisions

A. What are the analytical results and proposed decisions for this 
source category?

1. What are the results of the risk assessment and analyses?
    As described in section III of this preamble, for the Taconite Iron 
Ore Processing source category, we conducted a risk assessment for all 
HAP emitted. We present results of the risk assessment briefly below 
and in more detail in the Taconite Risk Report, which is available in 
Docket ID No. EPA-HQ-OAR-2017-0664.
a. Chronic Inhalation Risk Assessment Results
    Table 4 below provides a summary of the results of the inhalation 
risk assessment for the source category. For more details about the 
estimated emission levels for actual and allowable emissions rates and 
the risk assessment methods and results, see the Taconite Risk Report, 
available in Docket ID No. EPA-HQ-OAR-2017-0664.

                                Table 4--Taconite Iron Ore Processing Source Category Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                   Maximum individual      Estimated population at   Estimated annual cancer       Maximum chronic           Maximum
                                    cancer risk (in 1     increased risk of cancer    incidence  (cases per      noncancer TOSHI \1\     screening acute
                                        million)              >= 1-in-1 million               year)          -------------------------- noncancer HQ \2\
        Risk assessment        ------------------------------------------------------------------------------                          -----------------
                                  Based on     Based on     Based on     Based on     Based on     Based on     Based on     Based on
                                   actual     allowable      actual     allowable      actual     allowable      actual     allowable    Based on actual
                                 emissions    emissions    emissions    emissions    emissions    emissions    emissions    emissions       emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category...............            2            6       38,000       43,000        0.001        0.001          0.2          0.2  HQREL = <1
Whole Facility................            2  ...........       40,000  ...........        0.001  ...........          0.2  ...........  ................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The TOSHI is the sum of the chronic noncancer HQs for substances that affect the same target organ or organ system.
\2\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop HQ values.

    Based on the results of the inhalation risk modeling using the 
actual emissions estimates, as shown in Table 4 of this preamble, the 
maximum individual cancer risk based on actual emissions (lifetime) is 
estimated to be 2-in-1 million (driven by arsenic and nickel from 
fugitive dust and indurating sources), the estimated maximum chronic 
noncancer TOSHI value based on actual emissions is 0.2 (driven by 
manganese compounds from fugitive dust and ore crushing sources), and 
the maximum screening acute noncancer HQ value (off-facility site) is 
less than 1 (driven by arsenic from fugitive dust and ore crushing 
sources). The total estimated annual cancer incidence

[[Page 50675]]

(national) from these facilities based on actual emission levels is 
0.001 excess cancer cases per year or 1 case in every 1,000 years. The 
results using allowable emissions indicate that the estimated maximum 
individual cancer risk based on allowable emissions (lifetime) is 6-in-
1 million (driven by arsenic and nickel from fugitive dust and 
indurating sources) and the maximum chronic noncancer TOSHI value is 
0.2 (driven by manganese compounds from fugitive dust and ore crushing 
sources).
b. Screening Level Acute Risk Assessment Results
    Table 4 of this preamble shows the estimated acute risk results for 
the Taconite Iron Ore Processing source category. To estimate the peak 
emission rates from average emission rates, the screening analysis for 
acute impacts was based on an industry specific multiplier of 2 for 
indurating furnaces and a factor of 10 for all other emissions sources. 
For more detailed acute risk results, refer to the Taconite Risk 
Report, available in Docket ID No. EPA-HQ-OAR-2017-0664.
c. Multipathway Risk Screening Results
    Results of the worst-case Tier 1 multipathway screening analysis 
indicate that PB-HAP emissions (based on estimates of actual emissions) 
from each of the eight facilities in the source category exceed the 
screening threshold emissions rate for the carcinogenic PB-HAP 
(combined D/F, POM, and arsenic screening values) with a maximum 
screening value of 3,000 for arsenic emissions. For the noncarcinogenic 
PB-HAP, all eight facilities have screening values greater than 1 for 
cadmium emissions with a maximum screening value of 20, and seven 
facilities have screening values greater than 1 for mercury emissions 
with a maximum screening value of 40. For the PB-HAP and facilities 
that did not screen out at Tier 1, we conducted a Tier 2 multipathway 
screening analysis.
    The Tier 2 multipathway screen replaces some of the assumptions 
used in Tier 1 with site-specific data, the location of fishable lakes, 
and local wind direction and speed. In Tier 2, the gardener scenario is 
included to represent consumption of produce grown in rural gardens. It 
is important to note that, even with the inclusion of some site-
specific information in the Tier 2 analysis, the multipathway screening 
analysis is still a very conservative, health-protective assessment 
(i.e., upper-bound consumption of local fish, locally grown, and/or 
raised foods) and in all likelihood will yield results that serve as an 
upper-bound multipathway risk associated with a facility.
    Based on the Tier 2 screening analysis, seven facilities emitting 
arsenic, D/F, and POM emissions have Tier 2 cancer screening values 
greater than 1 for the farmer scenario with a maximum screening value 
of 300. Arsenic emissions are driving the risk for the farmer scenario 
as well as the gardener scenario with a maximum Tier 2 gardener 
scenario cancer screening value of 200. The maximum Tier 2 cancer 
screening value for the fisher scenario is 30, with arsenic driving the 
risk. When we considered the effect multiple facilities within the 
source category could have on common lake(s) in the modeling domain, 
the maximum cancer screening value is 40.
    For mercury, four facilities emit mercury emissions above the Tier 
2 noncancer screening threshold emissions rate, with at least one 
facility with a screening value of 10 for the fisher scenario. When we 
considered the effect multiple facilities within the source category 
could have on common lake(s) in the modeling domain, mercury emissions 
resulted in a noncancer screening value of 20, with seven facilities 
contributing to the risk levels at common lakes. For cadmium, two 
facilities emit cadmium emissions above the Tier 2 noncancer screening 
threshold emissions rate, with at least one facility with a screening 
value of 2 for the fisher scenario. When we considered the effect 
multiple facilities within the source category could have on common 
lake(s) in the modeling domain, cadmium emissions exceeded the 
noncancer screening threshold emissions rate by a factor of 3, with 
seven facilities contributing to the risk levels at common lakes.
    An exceedance of a screening threshold emissions rate (i.e., a 
screening value greater than 1) in any of the tiers cannot be equated 
with a risk value or a HQ or HI. Rather, it represents a high-end 
estimate of what the risk or hazard may be. It represents the high-end 
estimate of risk because we choose inputs from the upper end of the 
range of possible values for the influential parameters used in the 
screens; and we assume that the exposed individual exhibits ingestion 
behavior that would lead to a high total exposure. For more details on 
the multipathway screening results, refer to Appendix 10 of the 
Taconite Risk Report, available in Docket ID No. EPA-HQ-OAR-2017-0664. 
Thus, facility emissions exceeding the screening threshold emissions 
rate by a factor of 2 (i.e., a screening value of 2) for a non-
carcinogen can be interpreted to mean that we are confident that the HQ 
would be lower than 2. Similarly, facility emissions exceeding the 
cancer screening threshold emissions rate by a factor of 20 (i.e., a 
screening value of 20) for a carcinogen means that we are confident 
that the risk is lower than 20-in-1 million.
    Based upon the maximum Tier 2 screening values for mercury (fisher 
scenario) and arsenic (fisher and gardener scenario) occurring from the 
same location, we proceeded to a site-specific assessment using 
TRIM.FaTE versus conducting a Tier 3 screen. We also selected this site 
for assessing noncancer risks from cadmium utilizing the fisher 
scenario as the site was comparable to the maximum Tier 2 location. The 
selected site represents the combined contribution of mercury, arsenic 
and cadmium emissions from five taconite iron ore processing plants.
    The site selected was modeled using TRIM.FaTE to assess cancer risk 
from arsenic emissions and noncancer risks from mercury and cadmium 
emissions for the fisher and gardener scenarios. The final cancer risk 
based upon the fisher scenario and gardener scenario was less than 1-
in-1 million from arsenic emissions. The final noncancer risks had a HI 
less than 1 for mercury (0.02) and for cadmium (0.01). Further details 
on the site-specific multipathway assessment can be found in Appendix 
11 of the Taconite Risk Report, available in Docket ID No. EPA-HQ-OAR-
2017-0664.
d. Environmental Risk Screening Results
    As described in section III.C of this document, we conducted an 
environmental risk screening assessment for the Taconite Iron Ore 
Processing source category for the following pollutants: Arsenic, 
cadmium, D/F, HCl, HF, lead, mercury (methyl mercury and mercuric 
chloride), and POM.
    In the Tier 1 screening analysis for PB-HAP (other than lead, which 
was evaluated differently), D/F and POM emissions had no exceedances of 
any of the ecological benchmarks evaluated. Arsenic emissions had Tier 
1 exceedances for three surface soil benchmarks: Threshold level (plant 
communities), no-observed-adverse-effect-level (NOAEL) (avian ground 
insectivores--woodcock), and NOAEL (mammalian insectivores--shrew) with 
a maximum screening value of 4. Cadmium emissions had Tier 1 
exceedances for two surface soil benchmarks: NOAEL (mammalian 
insectivores--shrew) and NOAEL (avian ground insectivores--woodcock) 
with a

[[Page 50676]]

maximum screening value of 4. Cadmium emissions also had Tier 1 
exceedances for three fish--avian piscivores benchmarks: NOAEL 
(merganser), geometric-maximum-allowable-toxicant-level (GMATL) 
(merganser), and lowest-observed-adverse-effect-level (LOAEL) 
(merganser) with a maximum screening value of 3. Divalent mercury 
emissions had Tier 1 exceedances for the following benchmarks: Sediment 
threshold level, surface soil threshold level (plant communities), and 
surface soil threshold level (invertebrate communities) with a maximum 
screening value of 3. Methyl mercury had Tier 1 exceedances for the 
following benchmarks: fish (avian/piscivores), NOAEL (merganser), 
surface soil NOAEL (mammalian insectivores--shrew), and surface soil 
NOAEL for avian ground insectivores (woodcock) with a maximum screening 
value of 2.
    A Tier 2 screening analysis was performed for arsenic, cadmium, 
divalent mercury, and methyl mercury. In the Tier 2 screening analysis, 
there were no exceedances of any of the ecological benchmarks evaluated 
for any of the pollutants.
    For lead, we did not estimate any exceedances of the secondary lead 
NAAQS. For HCl and HF, the average modeled concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmark. In 
addition, each individual modeled concentration of HCl and HF (i.e., 
each off-site data point in the modeling domain) was below the 
ecological benchmarks for all facilities.
    Based on the results of the environmental risk screening analysis, 
we do not expect an adverse environmental effect as a result of HAP 
emissions from this source category.
e. Facility-Wide Risk Results
    Six facilities have a facility-wide cancer MIR greater than or 
equal to 1-in-1 million. The maximum facility-wide cancer MIR is 2-in-1 
million, driven by arsenic and nickel from fugitive dust and indurating 
emissions. The total estimated cancer incidence from the whole facility 
is 0.001 excess cancer cases per year, or one excess case in every 
1,000 years. Approximately 40,000 people were estimated to have cancer 
risks above 1-in-1 million from exposure to HAP emitted from both 
source category and non-source category sources at six of the eight 
facilities in this source category. The maximum facility-wide TOSHI for 
the source category is estimated to be 0.2, mainly driven by emissions 
of manganese from fugitive dust and ore crushing emissions.
f. What demographic groups might benefit from this regulation?
    To examine the potential for any environmental justice issues that 
might be associated with the source category, we performed a 
demographic analysis, which is an assessment of risks to individual 
demographic groups of the populations living within 5 km and within 50 
km of the facilities. In the analysis, we evaluated the distribution of 
HAP-related cancer and noncancer risks from the Taconite Iron Ore 
Processing source category across different demographic groups within 
the populations living near facilities.
    The results of the demographic analysis are summarized in Table 5 
below. These results, for various demographic groups, are based on the 
estimated risks from actual emissions levels for the population living 
within 50 km of the facilities.

             Table 5--Taconite Iron Ore Processing Source Category Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                                    Population
                                                                                    with cancer     Population
                                                                                    risk at or     with chronic
                                                                    Nationwide     above 1-in-1    noncancer HI
                                                                                  million due to  above 1 due to
                                                                                   taconite iron   taconite iron
                                                                                  ore processing  ore processing
----------------------------------------------------------------------------------------------------------------
    Total Population............................................     317,746,049          38,000               0
----------------------------------------------------------------------------------------------------------------
                                          White and Minority by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              62              93               0
Minority........................................................              38               7               0
----------------------------------------------------------------------------------------------------------------
                                           Minority Detail by Percent
----------------------------------------------------------------------------------------------------------------
African American................................................              12               1               0
Native American.................................................             0.8             2.8               0
Hispanic or Latino..............................................              18               1               0
Other and Multiracial...........................................               7               2               0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below the Poverty Level.........................................              14              19               0
Above the Poverty Level.........................................              86              82               0
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 Without High a School Diploma...........................              14               8               0
Over 25 With a High School Diploma..............................              86              92               0
----------------------------------------------------------------------------------------------------------------
                                       Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................................               6             0.2               0
----------------------------------------------------------------------------------------------------------------

[[Page 50677]]

    The results of the Taconite Iron Ore Processing source category 
risk assessment (described in section IV.A.1 of this preamble) 
indicates that actual emissions from the source category expose 
approximately 38,000 people to a cancer risk at or above 1-in-1 million 
and no one to a chronic noncancer HI greater than 1. The percent of 
minorities nationally (38 percent) is much higher than for the category 
population with cancer risk greater than or equal to 1-in-1 million (7 
percent). The category population with cancer risk greater than or 
equal to 1-in-1 million has a greater percentage of Native American 
(2.8 percent) as compared to nationally (0.8 percent), but lower 
percentages for African American (1 percent) and Hispanic (1 percent) 
as compared to nationally, 12 percent and 18 percent, respectively. The 
category population with cancer risk greater than or equal to 1-in-1 
million has about the same percentage of the population below the 
poverty level (18 percent) as compared to nationally (14 percent). The 
percentage of the population over 25 without a high school diploma and 
the percentage of the population that is linguistically isolated are 
lower for the category population (8 percent and 0.2 percent, 
respectively) than nationally (14 percent and 6 percent, respectively).
    The methodology and the results of the demographic analysis are 
presented in a technical report titled Risk and Technology Review--
Analysis of Demographic Factors for Populations Living Near Taconite 
Iron Ore Processing Source Category Operations, June 2019 (hereafter 
referred to as the Taconite Iron Ore Processing Demographic Analysis 
Report), which may be found in Docket ID No. EPA-HQ-OAR-2017-0664.
2. What are our proposed decisions regarding risk acceptability, ample 
margin of safety, and adverse environmental effect?
a. Risk Acceptability
    As noted in section III.A of this preamble, we weigh all health 
risk factors in our risk acceptability determination, including the 
cancer MIR, the number of persons in various cancer and noncancer risk 
ranges, cancer incidence, the maximum noncancer TOSHI, the maximum 
acute noncancer HQ, the extent of noncancer risks, the distribution of 
cancer and noncancer risks in the exposed population, and risk 
estimation uncertainties (54 FR 38044, September 14, 1989).
    For the Taconite Iron Ore Processing source category, the risk 
analysis indicates that the cancer risks to the individual most exposed 
could be up to 2-in-1 million due to actual emissions or up to 6-in-1 
million based on allowable emissions. These risks are considerably less 
than 100-in-1 million, which is the presumptive upper limit of 
acceptable risk. The risk analysis also shows very low cancer incidence 
(0.001 cases per year for actual and allowable emissions), and we did 
not identify a potential for adverse chronic noncancer health effects. 
The acute noncancer risks based on actual emissions are low, with a 
maximum HQ of less than 1 (based on the REL) for arsenic. Therefore, we 
find there is little potential concern of acute noncancer health 
impacts from actual emissions. In addition, the risk assessment 
indicates no significant potential for multipathway health effects.
    Considering all of the health risk information and factors 
discussed above, including the uncertainties discussed in section 
III.C.7 of this preamble, we propose to find that the risks from the 
Taconite Iron Ore Processing source category are acceptable.
b. Ample Margin of Safety Analysis
    Although we are proposing that the risks from the Taconite Iron Ore 
Processing source category are acceptable, we are required to consider 
whether the MACT standards for the source category provide an ample 
margin of safety to protect public health. The risk estimates show that 
approximately 38,000 individuals in the exposed population have a 
cancer risk above 1-in-1 million based on actual emissions and 43,000 
individuals have a cancer risk above 1-in-1 million based on allowable 
emissions. The MIR based on actual emissions is 2-in-1 million, and 
based on allowable emissions, the MIR is 6-in-1 million. With regard to 
chronic and acute noncancer risks, as described above in section 
IV.A.1, all HIs and HQs are below one. Under the ample margin of safety 
analysis, in addition to the health risks, we evaluated the cost and 
feasibility of available control technologies and other measures 
(including the controls, measures, and costs reviewed under the 
technology review as described in section III.B of this preamble) that 
could be applied to this source category to further reduce the risks 
(or potential risks) due to emissions of HAP identified in the risk 
assessment.
    In this analysis, we focused on cancer risks since all the chronic 
and acute noncancer HIs and HQs are below one. The cancer risks are 
driven by metal HAP emissions (e.g., arsenic, nickel, and chromium VI) 
from indurating furnaces and fugitive dust sources. The indurating 
furnaces are currently controlled via wet scrubbers. We evaluated the 
option of reducing emissions from indurating furnaces by installing a 
wet electrostatic precipitator (wet ESP) after the existing wet 
scrubbers. Under this scenario, we estimate that the current metal HAP 
emissions would be reduced by about 99.9 percent, and the MIR would be 
reduced from 2-in-1 million based on actual emissions and 6-in-1 based 
on allowable emissions to less than 1-in-1 million for both actual and 
allowable emissions. We estimate annual costs of about $167 million for 
the industry, with a cost effectiveness of about $16 million per ton of 
metal HAP reduced. Due to the relatively small reduction in risk and 
the substantial costs associated with this option, we are proposing 
that additional emissions controls for metal HAP from indurating 
furnaces are not necessary to provide an ample margin of safety to 
protect public health. See the technical memorandum titled Taconite 
Iron Ore Processing--Ample Margin of Safety Analysis, in Docket ID No. 
EPA-HQ-OAR-2017-0664 for details.
    For the other affected sources that emit metal HAP (i.e., ore 
crushing and handling operations, finished pellet handling operations, 
ore drying, and sources subject to the fugitive dust emission control 
plan), we did not identify any developments in processes, practices, or 
control technologies. Therefore, we are proposing that additional 
emissions controls for metal HAP from these affected sources are not 
necessary to provide an ample margin of safety to protect public 
health.
c. Environmental Effects
    The emissions data for the Taconite Iron Ore Processing source 
category indicate that eight environmental HAP are emitted by sources 
within this source category: Arsenic, cadmium, D/F, mercury, POM, lead, 
HCl, and HF.
    In the Tier 1 screening analysis for PB-HAP (other than lead, which 
was evaluated differently), D/F and POM emissions had no exceedances of 
any of the ecological benchmarks evaluated. Arsenic, cadmium, and 
mercury had Tier 1 exceedances for some of the benchmarks evaluated by 
a maximum screening value of 4. Therefore, a Tier 2 screening analysis 
was performed for arsenic, cadmium, and mercury. In the Tier 2 
screening analysis, there were no exceedances of any of the ecological 
benchmarks evaluated for any of the pollutants.
    The screening-level evaluation of the potential for adverse 
environmental

[[Page 50678]]

effects from emissions of lead indicated that the secondary NAAQS for 
lead would not be exceeded by any facility. The screening-level 
evaluation of the potential for adverse environmental effects 
associated with emissions of HCl and HF from the Taconite Iron Ore 
Processing source category indicated that each individual concentration 
(i.e., each off-site data point in the modeling domain) was below the 
ecological benchmarks for all facilities. In addition, we are unaware 
of any adverse environmental effects caused by HAP emitted by this 
source category. Therefore, we do not expect there to be an adverse 
environmental effect as a result of HAP emissions from this source 
category and we are proposing that it is not necessary to set a more 
stringent standard to prevent, taking into consideration costs, energy, 
safety, and other relevant factors, an adverse environmental effect.
B. What are the results and proposed decisions based on our technology 
review?
    The MACT standards for the Taconite Iron Ore Processing source 
category require compliance with numeric emission limits for PM, a 
surrogate for metal HAP, for ore crushing and handling operations, ore 
dryers, pellet induration furnaces, and finished pellet handling 
sources and for acid gases for pellet indurating furnaces. The rule 
requires work practice standards to reduce PM (again as a surrogate for 
metal HAP) emissions from fugitive dust emission sources (i.e., 
stockpiles, material transfer points, facility roadways, tailings 
basins, pellet loading areas, and yard areas). Furthermore, the rule 
includes operation and maintenance requirements for pellet indurating 
furnaces to ensure good combustion to minimize emissions of 
formaldehyde and other organic HAP that are products of incomplete 
combustion.
    Under the technology review we searched, reviewed, and considered 
several sources of information to determine whether there have been 
developments in practices, processes, and control technologies as 
required by section 112(d)(6) of the CAA. Section III.B of this 
preamble describes the types of information and factors we consider to 
determine if there have been any such ``developments.'' Our 
investigations included internet searches, discussions with industry 
representatives during site visits to taconite iron ore processing 
plants, a review of state permits, and a review of state air quality 
and regional haze implementation plans from Minnesota and Michigan, the 
two states where taconite iron ore processing plants are located.
    Particulate matter emissions from the pellet induration furnaces 
are controlled by wet scrubbers or wet ESPs. Based on our review, we 
identified wet ESPs as a potential development in control technology 
for indurating furnaces, as discussed under the ample margin of safety 
analysis (see section IV.A.2.b of this preamble). As described in our 
ample margin of safety analysis, we estimate the cost for implementing 
this control technology would be $167 million annualized costs for the 
source category, with estimated cost effectiveness of $16 million per 
ton of metal HAP. We are proposing that it is not necessary under CAA 
section 112(d)(6) to require these additional controls for indurating 
furnaces because of the high annualized costs and because these 
controls are not cost effective.
    With regard to the ore crushing and handling, ore drying, and 
finished pellet handling emissions sources as well as for fugitive dust 
emissions, based on our searches and reviews of the information sources 
described above, we did not identify any developments in practices, 
processes, or control technologies. For more details, refer to the 
document, Technology Review for the Taconite Iron Ore Processing Source 
Category, which is available in Docket ID No. EPA-HQ-OAR-2017-0664.

C. What other actions are we proposing?

    In addition to the proposed determinations described above, we are 
proposing some revisions to the NESHAP. We are proposing revisions to 
the SSM provisions of the MACT rule in order to ensure that they are 
consistent with the Court decision in Sierra Club v. EPA, 551 F. 3d 
1019 (DC Cir. 2008), which vacated two provisions that exempted sources 
from the requirement to comply with otherwise applicable CAA section 
112(d) emission standards during periods of SSM. We are also proposing 
the following: (1) Facilities can reduce compliance testing duration of 
individual runs from 2 hours to 1 hour; (2) to remove pressure drop as 
a monitoring option for dynamic wet scrubbers; (3) to remove the 
requirements for monitoring pressure drop and conducting quarterly 
internal baghouse inspections whenever the baghouse is equipped with a 
bag leak detection system; and (4) various other changes to clarify 
testing, monitoring, recordkeeping, and reporting requirements and to 
correct typographical errors. Furthermore, we are proposing a 
determination that a certain compound (known as elongated mineral 
particulate) is not a HAP. Our analyses, proposed changes, and proposed 
determination related to these issues are discussed below.
1. SSM
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (DC Cir. 
2008), the Court vacated portions of two provisions in the EPA's CAA 
section 112 regulations governing the emissions of HAP during periods 
of SSM. Specifically, the Court vacated the SSM exemption contained in 
40 CFR 63.6(f)(1) and (h)(1), holding that under section 302(k) of the 
CAA, emissions standards or limitations must be continuous in nature 
and that the SSM exemption violates the CAA's requirement that some 
section 112 standards apply continuously.
    Consistent with Sierra Club v. EPA, we are proposing the 
elimination of the SSM exemption in this NESHAP and we are proposing 
the standards apply at all times. We are also proposing several 
revisions to Table 2 (the General Provisions Applicability Table) which 
are explained in more detail below. For example, we are proposing to 
eliminate the incorporation of the General Provisions' requirement that 
sources develop an SSM plan. We also are proposing to eliminate and 
revise certain recordkeeping and reporting requirements related to the 
SSM exemption as described below.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary, or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so.
    In proposing the standards in this rule, the EPA has considered 
startup and shutdown periods and, for the reasons explained below, is 
not proposing alternative standards for those periods. The associated 
control devices are operational before startup and during shutdown of 
the affected sources at taconite iron ore processing facilities. 
Therefore, we expect that emissions during startup and shutdown would 
be no higher than emissions during normal operations. We know of no 
reason why the existing standards should not apply at all times.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment. (40 CFR 63.2) 
(definition of malfunction). The EPA

[[Page 50679]]

interprets CAA section 112 as not requiring emissions that occur during 
periods of malfunction to be factored into development of CAA section 
112 standards and this reading has been upheld as reasonable by the 
Court in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016). Under 
section 112, emissions standards for new sources must be no less 
stringent than the level ``achieved'' by the best controlled similar 
source and for existing sources generally must be no less stringent 
than the average emission limitation ``achieved'' by the best 
performing 12 percent of sources in the category. There is nothing in 
section 112 that directs the Agency to consider malfunctions in 
determining the level ``achieved'' by the best performing sources when 
setting emission standards. As the Court has recognized, the phrase 
``average emissions limitation achieved by the best performing 12 
percent of sources ``says nothing about how the performance of the best 
units is to be calculated.'' Nat'l Ass'n of Clean Water Agencies v. 
EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts for 
variability in setting emissions standards, nothing in CAA section 112 
requires the Agency to consider malfunctions as part of that analysis. 
The EPA is not required to treat a malfunction in the same manner as 
the type of variation in performance that occurs during routine 
operations of a source. A malfunction is a failure of the source to 
perform in a ``normal or usual manner'' and no statutory language 
compels the EPA to consider such events in setting CAA section 112 
standards.
    As the Court recognized in U.S. Sugar Corp, accounting for 
malfunctions in setting standards would be difficult, if not 
impossible, given the myriad different types of malfunctions that can 
occur across all sources in the category and given the difficulties 
associated with predicting or accounting for the frequency, degree, and 
duration of various malfunctions that might occur. Id. at 608 (``the 
EPA would have to conceive of a standard that could apply equally to 
the wide range of possible boiler malfunctions, ranging from an 
explosion to minor mechanical defects. Any possible standard is likely 
to be hopelessly generic to govern such a wide array of 
circumstances.''). As such, the performance of units that are 
malfunctioning is not ``reasonably'' foreseeable. See, e.g. Sierra Club 
v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999) (``The EPA typically has 
wide latitude in determining the extent of data-gathering necessary to 
solve a problem. We generally defer to an agency's decision to proceed 
on the basis of imperfect scientific information, rather than to 
'invest the resources to conduct the perfect study.' ''). See also, 
Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the 
nature of things, no general limit, individual permit, or even any 
upset provision can anticipate all upset situations. After a certain 
point, the transgression of regulatory limits caused by `uncontrollable 
acts of third parties,' such as strikes, sabotage, operator 
intoxication or insanity, and a variety of other eventualities, must be 
a matter for the administrative exercise of case-by-case enforcement 
discretion, not for specification in advance by regulation.''). In 
addition, emissions during a malfunction event can be significantly 
higher than emissions at any other time of source operation. For 
example, if an air pollution control device with 99-percent removal 
goes off-line as a result of a malfunction (as might happen if, for 
example, the bags in a baghouse catch fire) and the emission unit is a 
steady state type unit that would take days to shut down, the source 
would go from 99-percent control to zero control until the control 
device was repaired. The source's emissions during the malfunction 
would be 100 times higher than during normal operations. As such, the 
emissions over a 4-day malfunction period would exceed the annual 
emissions of the source during normal operations. As this example 
illustrates, accounting for malfunctions could lead to standards that 
are not reflective of (and significantly less stringent than) levels 
that are achieved by a well-performing non-malfunctioning source. It is 
reasonable to interpret CAA section 112 to avoid such a result. The 
EPA's approach to malfunctions is consistent with CAA section 112 and 
is a reasonable interpretation of the statute.
    Although no statutory language compels the EPA to set standards for 
malfunctions, the EPA has the discretion to do so where feasible. For 
example, in the Petroleum Refinery Sector RTR, the EPA established a 
work practice standard for unique types of malfunction that result in 
releases from pressure relief devices (PRDs) or emergency flaring 
events because the EPA had information to determine that such work 
practices reflected the level of control that applies to the best 
performers. 80 FR 75178, 75211-14 (December 1, 2015). The EPA will 
consider whether circumstances warrant setting standards for a 
particular type of malfunction and, if so, whether the EPA has 
sufficient information to identify the relevant best performing sources 
and establish a standard for such malfunctions. (We also encourage 
commenters to provide any such information.)
    Based on the EPA's knowledge of the processes and engineering 
judgement, malfunctions in the Taconite Iron Ore Processing source 
category are considered unlikely to result in a violation of the 
standard. Affected sources at taconite iron ore processing plants are 
controlled with add-on air pollution control devices which will 
continue to function in the event of a process upset. Also, processes 
in the industry are typically equipped with controls that will not 
allow startup of the emission source until the associated control 
device is operating and will automatically shut down the emission 
source if the associated controls malfunction. Indurating furnaces, 
which are the largest sources of HAP emissions, typically operate 
continuously for long periods of time with no significant spikes in 
emissions. These minimal fluctuations in emissions are controlled by 
the existing add-on air pollution control devices used at all plants in 
the industry.
    In the unlikely event that a source fails to comply with the 
applicable CAA section 112(d) standards as a result of a malfunction 
event, the EPA would determine an appropriate response based on, among 
other things, the good faith efforts of the source to minimize 
emissions during malfunction periods, including preventative and 
corrective actions, as well as root cause analyses to ascertain and 
rectify excess emissions. The EPA would also consider whether the 
source's failure to comply with the CAA section 112(d) standard was, in 
fact, sudden, infrequent, not reasonably preventable, and was not 
instead caused, in part, by poor maintenance or careless operation. 40 
CFR 63.2 (definition of malfunction).
    If the EPA determines in a particular case that an enforcement 
action against a source for violation of an emission standard is 
warranted, the source can raise any and all defenses in that 
enforcement action and the federal district court will determine what, 
if any, relief is appropriate. The same is true for citizen enforcement 
actions. Similarly, the presiding officer in an administrative 
proceeding can consider any defense raised and determine whether 
administrative penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular, 
section 112, is reasonable and encourages practices that will avoid 
malfunctions.

[[Page 50680]]

Administrative and judicial procedures for addressing exceedances of 
the standards fully recognize that violations may occur despite good 
faith efforts to comply and can accommodate those situations. U.S. 
Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.6(e)(1)(i) by changing the ``yes'' 
in the column titled ``Applies to Subpart RRRRR'' to a ``no.'' Section 
63.6(e)(1)(i) describes the general duty to minimize emissions. Some of 
the language in that section is no longer necessary or appropriate in 
light of the elimination of the SSM exemption. We are proposing instead 
to add general duty regulatory text at 40 CFR 63.9600(a) that reflects 
the general duty to minimize emissions while eliminating the reference 
to periods covered by an SSM exemption. The current language in 40 CFR 
3.6(e)(1)(i) characterizes what the general duty entails during periods 
of SSM. With the elimination of the SSM exemption, there is no need to 
differentiate between normal operations and SSM events in describing 
the general duty. Therefore, the language the EPA is proposing for 40 
CFR 63.9600(a) does not include that language from 40 CFR 63.6(e)(1).
    We are also proposing to revise the General Provisions 
Applicability Table (Table 2) entry for 40 CFR 63.6(e)(1)(ii) by 
changing the ``yes'' in the column titled ``Applies to Subpart RRRRR'' 
to a ``no.'' Section 63.6(e)(1)(ii) imposes requirements that are not 
necessary with the elimination of the SSM exemption or are redundant 
with the general duty requirement being added at 40 CFR 63.9600(a).
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.6(e)(3) by changing the ``yes'' in 
the column titled ``Applies to Subpart RRRRR'' to a ``no.'' Generally, 
these paragraphs require development of an SSM plan and specify SSM 
recordkeeping and reporting requirements related to the SSM plan. As 
noted, the EPA is proposing to remove the SSM exemptions. Therefore, 
affected units will be subject to an emission standard during such 
events. The applicability of a standard during such events will ensure 
that sources have ample incentive to plan for and achieve compliance 
and, thus, the SSM plan requirements are no longer necessary.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.6(f)(1) by changing the ``yes'' in 
the column titled ``Applies to Subpart RRRRR'' to a ``no.'' The current 
language of 40 CFR 63.6(f)(1) exempts sources from non-opacity 
standards during periods of SSM. As discussed above, the Court in 
Sierra Club v. EPA vacated the exemptions contained in this provision 
and held that the CAA requires that some CAA section 112 standards 
apply continuously. Consistent with Sierra Club v. EPA, the EPA is 
proposing to revise standards in this rule to apply at all times.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in 
the column titled ``Applies to Subpart RRRRR'' to a ``no.'' Section 
63.7(e)(1) describes performance testing requirements. The EPA is 
instead proposing to add a performance testing requirement at 40 CFR 
63.9621(a). The performance testing requirements we are proposing to 
add differ from the General Provisions performance testing provisions 
in several respects. The regulatory text removes the cross-reference to 
40 CFR 63.7(e)(1) and does not include the language in 40 CFR 
63.7(e)(1) that restated the SSM exemption and language that precluded 
startup and shutdown periods from being considered ``representative'' 
for purposes of performance testing. The proposed performance testing 
provisions will not allow performance testing during malfunctions. As 
in 40 CFR 63.7(e)(1), performance tests conducted under this subpart 
should not be conducted during malfunctions because conditions during 
malfunctions are often not representative of normal operating 
conditions. The EPA is proposing to add language that requires the 
owner or operator to 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. Section 63.7(e) requires that the owner or operator make 
available to the Administrator such records ``as may be necessary to 
determine the condition of the performance test'' available to the 
Administrator upon request but does not specifically require the 
information to be recorded. The regulatory text the EPA is proposing to 
add to this provision builds on that requirement and makes explicit the 
requirement to record the information.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.8(c)(1)(i) and (iii) by changing 
the ``yes'' in the column titled ``Applies to Subpart RRRRR'' to a 
``no.'' The cross-references to the general duty and SSM plan 
requirements in those subparagraphs are not necessary in light of other 
requirements of 40 CFR 63.8 that require good air pollution control 
practices (40 CFR 63.8(c)(1)) and that set out the requirements of a 
quality control program for monitoring equipment (40 CFR 63.8(d)).
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.8(d)(3) by changing the ``yes'' in 
the column titled ``Applies to Subpart RRRRR'' to a ``no.'' The final 
sentence in 40 CFR 63.8(d)(3) refers to the General Provisions' SSM 
plan requirement which is no longer applicable. The EPA is proposing to 
add to the rule at 40 CFR 63.9632(b)(5) text that is identical to 40 
CFR 63.8(d)(3) except for the final sentence with the reference to SSM.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.10(b)(2)(i) by changing the ``yes'' 
in the column titled ``Applies to Subpart RRRRR'' to a ``no.'' Section 
63.10(b)(2)(i) describes the recordkeeping requirements during startup 
and shutdown. These recording provisions are no longer necessary 
because the EPA is proposing that recordkeeping and reporting 
applicable to normal operations will apply to startup and shutdown. In 
the absence of special provisions applicable to startup and shutdown, 
such as a startup and shutdown plan, there is no reason to retain 
additional recordkeeping for startup and shutdown periods.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.10(b)(2)(ii) by changing the 
``yes'' in the column titled ``Applies to Subpart RRRRR'' to a ``no.'' 
Section 63.10(b)(2)(ii) describes the recordkeeping requirements during 
a malfunction. The EPA is proposing to add such requirements to 40 CFR 
63.9642. The regulatory text we are proposing to add differs from the 
General Provisions it is replacing in that the General Provisions 
requires the creation and retention of a record of the occurrence and 
duration of each malfunction of process, air pollution control, and 
monitoring equipment. The EPA is proposing that this requirement apply 
to any failure to meet an applicable standard and is requiring that the 
source record the date, time, and duration of the failure rather than 
the ``occurrence.'' The EPA is also proposing to add to 40 CFR 63.9642 
a requirement that sources keep records that include a list of the 
affected source or equipment and actions taken to minimize emissions, 
an estimate of the quantity of each regulated pollutant emitted over 
the standard for which the source failed to meet the standard, and a 
description of the method used to

[[Page 50681]]

estimate the emissions. Examples of such methods would include product-
loss calculations, mass balance calculations, measurements when 
available, or engineering judgment based on known process parameters. 
The EPA is proposing to require that sources keep records of this 
information to ensure that there is adequate information to allow the 
EPA to determine the severity of any failure to meet a standard, and to 
provide data that may document how the source met the general duty to 
minimize emissions when the source has failed to meet an applicable 
standard.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.10(b)(2)(iv) by changing the 
``yes'' in the column titled ``Applies to Subpart RRRRR'' to a ``no.'' 
When applicable, the provision requires sources to record actions taken 
during SSM events when actions were inconsistent with their SSM plan. 
The requirement is no longer appropriate because SSM plans will no 
longer be required. The requirement previously applicable under 40 CFR 
63.10(b)(2)(iv)(B) to record actions to minimize emissions and record 
corrective actions is now applicable by reference to 40 CFR 63.9642.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.10(b)(2)(v) by changing the ``yes'' 
in the column titled ``Applies to Subpart RRRRR'' to a ``no.'' When 
applicable, the provision requires sources to record actions taken 
during SSM events to show that actions taken were consistent with their 
SSM plan. The requirement is no longer appropriate because SSM plans 
will no longer be required.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.10(c)(15) by changing the ``yes'' 
in the column titled ``Applies to Subpart RRRRR'' to a ``no.'' The EPA 
is proposing that 40 CFR 63.10(c)(15) no longer applies. When 
applicable, the provision allows an owner or operator to use the 
affected source's SSM plan or records kept to satisfy the recordkeeping 
requirements of the SSM plan, specified in 40 CFR 63.6(e), to also 
satisfy the requirements of 40 CFR 63.10(c)(10) through (12). The EPA 
is proposing to eliminate this requirement because SSM plans would no 
longer be required, and, therefore, 40 CFR 63.10(c)(15) no longer 
serves any useful purpose for affected units.
    We are proposing to revise the General Provisions Applicability 
Table (Table 2) entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in 
the column titled ``Applies to Subpart RRRRR'' to a ``no.'' Section 
63.10(d)(5) describes the reporting requirements for startups, 
shutdowns, and malfunctions. To replace the General Provisions 
reporting requirement, the EPA is proposing to add reporting 
requirements to 40 CFR 63.9641. The replacement language differs from 
the General Provisions requirement in that it eliminates periodic SSM 
reports as a stand-alone report. We are proposing language that 
requires sources that fail to meet an applicable standard at any time 
to report the information concerning such events in the semi-annual 
compliance report already required under this rule. We are proposing 
that the report must contain the number, date, time, duration, and the 
cause of such events (including unknown cause, if applicable), a list 
of the affected source or equipment, an estimate of the quantity of 
each regulated pollutant emitted over any emission limit, and a 
description of the method used to estimate the emissions.
    Examples of such methods would include product-loss calculations, 
mass balance calculations, measurements when available, or engineering 
judgment based on known process parameters. The EPA is proposing this 
requirement to ensure that there is adequate information to determine 
compliance, to allow the EPA to determine the severity of the failure 
to meet an applicable standard, and to provide data that may document 
how the source met the general duty to minimize emissions during a 
failure to meet an applicable standard.
    We will no longer require owners or operators to determine whether 
actions taken to correct a malfunction are consistent with an SSM plan, 
because SSM plans would no longer be required. The proposed amendments, 
therefore, eliminate the cross-reference to 40 CFR 63.10(d)(5)(i) that 
contains the description of the previously required SSM report format 
and submittal schedule from this section. These specifications are no 
longer necessary because the events will be reported in otherwise 
required reports with similar format and submittal requirements.
    The proposed amendments eliminate the cross-reference to 40 CFR 
63.10(d)(5)(ii), which requires an immediate report for SSM when a 
source failed to meet an applicable standard but did not follow the SSM 
plan. We will no longer require owners and operators to report when 
actions taken during a startup, shutdown, or malfunction were not 
consistent with an SSM plan, because SSM plans would no longer be 
required.
2. Electronic Reporting
    The EPA is proposing that owners and operators of taconite iron ore 
processing plants submit electronic copies of required performance test 
reports and compliance reports through EPA's Central Data Exchange 
(CDX) using the Compliance and Emissions Data Reporting Interface 
(CEDRI). A description of the electronic data submission process is 
provided in the memorandum, Electronic Reporting Requirements for New 
Source Performance Standards (NSPS) and National Emission Standards for 
Hazardous Air Pollutants (NESHAP) Rules, available in Docket ID No. 
EPA-HQ-OAR-2017-0664. The proposed rule requires that performance test 
results collected using test methods that are supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the ERT website \21\ at 
the time of the test be submitted in the format generated through the 
use of the ERT and that other performance test results be submitted in 
portable document format (pdf) using the attachment module of the ERT. 
For compliance reports, the proposed rule requires that owners and 
operators use the appropriate spreadsheet template to submit 
information to CEDRI. A draft version of the proposed template for 
these reports is included in the docket for this rulemaking. The EPA 
specifically requests comment on the content, layout, and overall 
design of the template.
---------------------------------------------------------------------------

    \21\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    Additionally, we have identified two broad circumstances in which 
electronic reporting extensions may be provided. In both circumstances, 
the decision to accept the claim of needing additional time to report 
is within the discretion of the Administrator, and reporting should 
occur as soon as possible. We are providing these potential extensions 
to protect owners and operators from noncompliance in cases where they 
cannot successfully submit a report by the reporting deadline for 
reasons outside of their control. The situation where an extension may 
be warranted due to outages of EPA's CDX or CEDRI which precludes an 
owner or operator from accessing the system and submitting required 
reports is addressed in 40 CFR 63.9641. The situation where an 
extension may be warranted due to a force majeure event, which is 
defined as an event that will be or has been caused by circumstances 
beyond the control of the affected facility, its contractors, or any 
entity controlled by

[[Page 50682]]

the affected facility that prevents an owner or operator from complying 
with the requirement to submit a report electronically as required by 
this rule is addressed in 40 CFR 63.9641. Examples of such events are 
acts of nature, acts of war or terrorism, or equipment failure or 
safety hazards beyond the control of the facility.
    The electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends in data availability and 
transparency, and will further assist in the protection of public 
health and the environment. Furthermore, it will improve compliance by 
facilitating the ability of regulated facilities to demonstrate 
compliance with requirements and by facilitating the ability of 
delegated state, local, tribal, and territorial air agencies and the 
EPA to assess and determine compliance, and will ultimately reduce 
burden on regulated facilities, delegated air agencies, and the EPA. 
Electronic reporting also eliminates paper-based, manual processes, 
thereby saving time and resources, simplifying data entry, eliminating 
redundancies, minimizing data reporting errors, and providing data 
quickly and accurately to the affected facilities, air agencies, the 
EPA, and the public. Moreover, electronic reporting is consistent with 
the EPA's plan \22\ to implement Executive Order 13563 and is in 
keeping with the EPA's Agency-wide policy \23\ developed in response to 
the White House's Digital Government Strategy.\24\ For more information 
on the benefits of electronic reporting, see the memorandum, Electronic 
Reporting Requirements for New Source Performance Standards (NSPS) and 
National Emission Standards for Hazardous Air Pollutants (NESHAP) 
Rules, available in Docket ID No. EPA-HQ-OAR-2017-0664.
---------------------------------------------------------------------------

    \22\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \23\ E-Reporting Policy Statement for EPA Regulations, September 
2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \24\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

3. Performance Testing
    The Taconite Iron Ore Processing NESHAP performance testing 
requirements specify that stack tests conducted for ore crushing and 
handling, finished pellet handling, ore drying, and indurating furnace 
affected sources must consist of three separate runs of a minimum of 2 
hours for each run. Industry representatives have stated that 2-hour 
test runs are unnecessary because an adequate sample volume can be 
obtained when conducting a 1-hour test. Industry representatives also 
pointed out that Minnesota state rules for performance testing only 
require that test runs be 1 hour in duration. They claim longer run 
time increases the cost of testing without any improvement in the data 
collected. With the time needed for test contractors to set up and 
break down their sampling equipment, perform the necessary QA/QC 
checks, and conduct a minimum of 6 hours of testing for a three-run 
test on a single stack, testing can take 9 to 10 hours to complete.
    The EPA has previously concluded that the representative method 
detection limit for EPA Method 5 of 40 CFR part 60, appendix A-3, is 2 
milligrams for a sample volume of 1 dry standard cubic meter.\25\ This 
is the approximate sample volume for a 1-hour test run. This detection 
limit is equivalent to 0.0026 gr/dscf, which is well below the emission 
limits in this rule. Additionally, we reviewed a number of test reports 
submitted during the development of this action. After examining those 
PM test results, we did not find any of the test results to be below 
the method detection limit, even when the test run was only 1 hour 
long.
---------------------------------------------------------------------------

    \25\ U.S. EPA. Memorandum from Conniesue Oldham to Bob Schell. 
Revision of Estimated Method 5 Detection Limit. June 15, 2012.
---------------------------------------------------------------------------

    Based upon our review of available information, we agree that a 
test run time of 1 hour should provide an adequate sample volume to 
determine compliance with the emission limits if good testing practices 
are followed. Therefore, we are proposing to revise the minimum time 
for test runs for performance tests conducted on ore crushing and 
handling, finished pellet handling, ore drying, and indurating furnace 
affected sources from a minimum of 2 hours for each test run to a 
minimum of 1 hour for each test run. While we agree that this change 
should not cause an issue with determining compliance, as the number of 
samples below the method detection limit should not increase as long as 
good testing practices are followed, we are also proposing that if the 
measurement result is reported as below the method detection limit, the 
method detection limit will be used for that value when calculating the 
average particulate concentration.
    Performance testing of indurating furnaces is required no less 
frequently than twice per 5-year permit term. Industry has requested 
that the EPA revise the frequency to once every 5 years if the 
performance test results are less than 80 percent of the emissions 
limit. We currently do not have sufficient justification or data to 
support this change. Therefore, we are not proposing this change. 
However, we solicit comments, data, and information as to whether this 
change would be appropriate or if other possible alternatives to the 
current requirement should be considered that would provide the 
industry more flexibility while ensuring that emissions would remain 
below the PM limits. In particular, we are interested in emissions data 
or other information that would support a margin of 80 percent, or some 
other margin, as sufficient to ensure that emissions would not exceed 
the emission limits for the 5-year period.
4. Baghouse Monitoring
    Under the current rule, baghouses that are used on affected sources 
to comply with the emission limits for PM are required to be equipped 
with a bag leak detection system in order to monitor the relative 
change in PM loadings. The current rule contains installation, 
operation, and maintenance requirements that apply to bag leak 
detection systems to ensure their proper performance. The Taconite Iron 
Ore Processing NESHAP also requires that the owner or operator monitor 
the daily pressure drop across each baghouse in addition to conducting 
physical inspections of several baghouse components on a daily, weekly, 
or monthly basis depending on the baghouse component. Then, the 
interior of the baghouse must be inspected on a quarterly basis to 
determine if there are air leaks. In view of the requirement for 
baghouses to be equipped with a bag leak detection system, the 
requirements to monitor baghouse pressure drop and to conduct baghouse 
inspections are redundant and, therefore unnecessary. Therefore, we are 
proposing to remove the requirements for conducting quarterly internal 
baghouse inspections whenever the baghouse is equipped with a bag leak 
detection system that is installed, operated, and maintained in 
compliance with the requirements in the Taconite Iron Ore Processing 
NESHAP. The use of bag leak detection systems is superior to older 
methods of monitoring baghouse performance (such as visual inspections) 
and is more consistent with monitoring

[[Page 50683]]

requirements for baghouses required in other EPA regulations.
    Industry has also requested that the EPA revise the requirement at 
40 CFR 63.9600(b)(2) to initiate corrective action to determine the 
cause of a bag leak detection system alarm within 1 hour of its 
occurrence. We currently do not have sufficient justification or data 
to support this change. Therefore, we are not proposing this change. 
However, we solicit comments, data, and information as to whether a 
longer time frame within which industry is required to initiate 
corrective action would be appropriate, or if other possible 
alternatives to the current requirement should be considered that would 
provide the industry more flexibility while ensuring that emissions 
would remain below the PM limits.
5. Dynamic Wet Scrubbers
    The current rule requires that where dynamic wet scrubbers, also 
known as low energy scrubbers, are used to comply with PM emission 
limits, the owner or operator must establish site-specific operating 
limits for scrubber water flow rate and either fan amperage or pressure 
drop during the PM performance testing for each dynamic wet scrubber. 
Compliance with the operating limits is determined by monitoring the 
daily average scrubber water flow rate and either the daily average fan 
amperage or the daily average pressure drop. Since the MACT rule was 
promulgated, we have determined that pressure drop is not adequate for 
monitoring dynamic scrubbers as the pressure drop for these scrubbers 
is very low and does not vary greatly. Furthermore, the operator is not 
able to adjust or control the differential pressure in order to remain 
in compliance. Therefore, we are proposing to remove pressure drop as a 
monitoring option for dynamic wet scrubbers. Under the proposed 
amendments, dynamic wet scrubbers used to comply with the Taconite Iron 
Ore Processing NESHAP emission limits for PM would be required to 
establish and monitor the scrubber water flow rate and fan amperage. 
While we maintain that scrubber water flow is an appropriate operating 
parameter for these scrubbers, we request comment on whether an 
operating parameter other than fan amperage or pressure drop would be 
as effective or more appropriate to monitor in conjunction with 
scrubber water flow to ensure the continued removal efficiency of the 
scrubber.
6. Performance Testing of Similar Sources
    Under the current rule, the owner/operator may elect to group up to 
six similar ore crushing and handling operations and finished pellet 
handling operations sources and conduct a compliance test on a single 
representative unit. The rule establishes the criteria that emission 
units must meet to be considered similar. This provision has the 
benefit of reducing testing costs for those facilities that can take 
advantage of it. Industry representatives requested that the EPA modify 
the rule language to allow up to 10 emission units in a group of 
similar sources. However, we currently do not have sufficient 
justification or data to support this change. Therefore, we are not 
proposing revisions to this requirement at this time. However, we 
request comments and information from companies and other stakeholders 
on the positive and/or negative aspects of increasing the number of 
similar sources that can be grouped for testing purposes, including the 
potential economic benefits for companies and potential environmental 
impacts, and whether the EPA should allow such an increase in the 
number of units in a group of similar sources for testing, and if so, 
why.
7. Elongated Mineral Particulate
    In 2004, after promulgation of the original Taconite Iron Ore 
Processing NESHAP, the National Wildlife Federation filed a petition 
for review of that rule with the Court (Case No. 03-1458). In that 
petition, the National Wildlife Federation alleged that the EPA had 
failed to set standards for what they believed to be emissions of 
asbestos, or asbestos-like fibers, from taconite iron ore processing 
plants. We are referring to these compounds as amphibole ``elongated 
mineral particulate (EMP).'' The EPA subsequently requested, and was 
granted, a partial voluntary remand to further investigate this issue 
and consider possible options to address the issue, as appropriate. As 
part of the development of this RTR proposed rulemaking, we gathered 
and reviewed available information on the amphibole EMP. Based on 
available information, amphibole EMP emissions only occur from the 
operations at one of the taconite iron ore processing plants, due to 
the effects of the Duluth Gabbro Complex on the associated taconite 
iron ore mine--specifically, the Peter Mitchell Mine associated with 
the Northshore Mining Company processing plant located in Silver Bay, 
Minnesota.
    After reviewing and evaluating available information, we have 
determined that the EMP do not meet the definition of ``asbestos'' 
found in current EPA regulations and technical documents. This is 
because asbestos is always defined as the asbestiform varieties of 
certain minerals (see 40 CFR 61.141, 763.83, and 763.163), whereas the 
EMP in question developed in the non-asbestiform geologic form. Also, a 
study by Ross et al. (The search for asbestos within the Peter Mitchell 
Taconite iron ore mine, near Babbitt, Minnesota, which is available in 
the docket, Docket ID No. EPA-HQ-OAR-2017-0664) found no asbestos in 
the Peter Mitchell Mine. Ross et al. analyzed 53 samples from 30 sites 
within the mine where fibrous minerals were thought to potentially 
occur. Samples were analyzed using transmission electron microscopes 
and other state-of-the-art equipment. No asbestos of any type was found 
in the mine pit samples. In another study by Wilson et al., ambient air 
samples from monitors at the taconite mill and in a nearby town were 
analyzed. It was found that the fibers collected by the ambient air 
monitors were non-asbestiform ferroactinolite and grunerite, not 
asbestos. (Risk assessment due to environmental exposures to fibrous 
particulates associated with taconite ore, which is available in the 
docket, Docket ID No. EPA-HQ-OAR-2017-0664.)
    We also evaluated the EMP to determine if they might meet the 
definition of ``fine mineral fibers'' (the other HAP listed in CAA 
section 112(b) which we initially thought might be interpreted to 
include EMP). Footnote 3 after the list of HAP found in CAA section 
112(b)(1) explains that ``[f]ine mineral fibers includes mineral fiber 
emissions from facilities manufacturing or processing glass, rock or 
slag fibers (or other mineral derived fibers) of average diameter 1 
micrometer or less.'' The EPA Health Effects Notebook (available at 
https://www.epa.gov/haps/health-effects-notebook-hazardous-air-pollutants) further explains that the term ``fine mineral fibers'' was 
intended to apply to the synthetic vitreous fibers glasswool, rockwool, 
slagwool, glass filaments, and refractory ceramic fibers. Based on the 
CAA definition, and further interpretation provided in the EPA Health 
Effects Notebook, we conclude that EMP do not meet the definition of 
``fine mineral fibers'' because the taconite iron ore processing 
facilities are not manufacturing or processing synthetic vitreous 
fibers such as rockwool, glasswool, slagwool, glass filaments, and 
refractory ceramic fibers.
    Since the EMP do not meet the definition of HAP pursuant to CAA

[[Page 50684]]

section 112(b), the EPA did not review the EMP for regulation under CAA 
section 112. Nevertheless, we note that the EMP are a component of PM 
which are subject to control by the NESHAP as a surrogate for metal HAP 
and acid gases. We also note that the Minnesota Pollution Control 
Agency requires this facility to monitor the EMP and ensure ambient 
levels of EMP near the facility are no higher than levels found in a 
non-affected location (i.e., St. Paul, Minnesota). Also, EMP are the 
subject of an exposure study being conducted in taconite communities in 
Minnesota by the EPA's Office of Research and Development (ORD) and the 
EPA's Region 5 office. More information on the EPA's review of the EMP 
and EPA's proposed determination is available in the memorandum, EPA's 
Analysis of Elongated Mineral Particulate, which is available in Docket 
ID No. EPA-HQ-OAR-2017-0664.

E. What compliance dates are we proposing?

    We are proposing that existing facilities must comply with all 
changes proposed in this action 180 days after promulgation of the 
final rule. All new or reconstructed facilities must comply with all 
requirements in the final rule upon startup. Our experience with 
similar industries that are required to convert reporting mechanisms, 
install necessary hardware and software, become familiar with the 
process of submitting performance test results electronically through 
the EPA's CEDRI, test these new electronic submission capabilities, 
reliably employ electronic reporting, and convert logistics of 
reporting processes to different time-reporting parameters, shows that 
a time period of a minimum of 90 days, and more typically, 180 days, is 
generally necessary to successfully complete these changes. Our 
experience with similar industries further shows that this sort of 
regulated facility generally requires a time period of 180 days to read 
and understand the amended rule requirements; evaluate their operations 
to ensure that they can meet the standards during periods of startup 
and shutdown as defined in the rule and make any necessary adjustments; 
adjust parameter monitoring and recording systems to accommodate 
revisions; and update their operations to reflect the revised 
requirements. The EPA recognizes the confusion that multiple different 
compliance dates for individual requirements would create and the 
additional burden such an assortment of dates would impose. From our 
assessment of the time frame needed for compliance with the entirety of 
the revised requirements, the EPA considers a period of 180 days to be 
the most expeditious compliance period practicable, and, thus, is 
proposing that existing affected sources be in compliance with all of 
this regulation's revised requirements within 180 days of the 
regulation's effective date.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    The Taconite Iron Ore Processing source category consists of eight 
facilities. One facility (Empire Mine) that is currently in a state of 
indefinite idle, is expected to resume operations once market 
conditions become more favorable. Also, a new facility is under 
construction near Nashwauk, Minnesota. The date that this new facility 
will begin operations is unknown, but not expected until after 
completion of this rulemaking. The affected sources at a taconite iron 
ore processing plant include ore crushing and handling operations, ore 
dryers, indurating furnaces, and finished pellet handling operations. 
The owner/operator of a taconite iron ore processing plant must also 
prepare and operate according to a fugitive dust emissions control plan 
to minimize emissions from sources of fugitive emissions (e.g., 
stockpiles, tailings basins, roadways, pellet loading areas, material 
transfer points, and yard areas).

B. What are the air quality impacts?

    In this action, we are proposing no new emission limits and no 
additional controls; therefore, no air quality impacts are expected as 
a result of the proposed amendments.

C. What are the cost impacts?

    The proposed amendments include no changes to emission standards or 
add-on controls. As described in section IV.C.3 of this preamble, the 
proposed amendments would reduce emissions performance test run times 
from 2 hours to 1 hour and remove the unnecessary requirement to 
conduct quarterly internal visual inspections of baghouses that are 
equipped with a bag leak detection system. The proposed amendments 
would replace the current reporting requirements with electronic 
reporting. Electronic reporting eliminates paper-based, manual 
processes, thereby saving time and resources, simplifying data entry, 
eliminating redundancies, and minimizing data reporting errors, 
ultimately reducing the burden on regulated facilities. Therefore, the 
proposed amendments impose no additional costs. In fact, the amendments 
and clarifications to rule language are expected to result in a 
reduction of current costs because compliance will be more 
straightforward. As described in the cost memorandum, we estimate the 
proposed amendments will result in an overall cost savings of $190,000 
per year mainly due to the reduced testing duration and elimination of 
need for internal visual baghouse inspections.

D. What are the economic impacts?

    Economic impact analyses focus on changes in market prices and 
output levels. If changes in market prices and output levels in the 
primary markets are significant enough, impacts on other markets may 
also be examined. Both the magnitude of costs associated with the 
proposed requirements and the distribution of these costs among 
affected facilities can have a role in determining how the market will 
change in response to a proposed rule. Because the overall costs and 
savings associated with the proposed revisions are relatively small, no 
significant economic impacts from the proposed amendments are 
anticipated.

E. What are the benefits?

    While the proposed amendments would not result in reductions in 
emissions of HAP, this action, if finalized, would result in improved 
monitoring, compliance, and implementation of the rule. Also, the 
electronic reporting requirements will enhance transparency by making 
performance test results and compliance reports more readily available 
to the public.

VI. Request for Comments

    We solicit comments on this proposed action. In addition to general 
comments on this proposed action, we are also interested in additional 
data that may improve the risk assessments and other analyses. We are 
specifically interested in receiving any improvements to the data used 
in the site-specific emissions profiles used for risk modeling. Such 
data should include supporting documentation in sufficient detail to 
allow characterization of the quality and representativeness of the 
data or information. Section VII of this preamble provides more 
information on submitting data.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR website at https://www.epa.gov/

[[Page 50685]]

stationary-sources-air-pollution/taconite-iron-ore-processing-national-
emission-standards-hazardous. The data files include detailed 
information for each HAP emissions release point for the facilities in 
the source category.
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern, and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. To submit comments on the data downloaded from the 
RTR website, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID No. EPA-HQ-OAR-2017-0664 (through the method described in the 
ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility 
(or facilities). We request that all data revision comments be 
submitted in the form of updated Microsoft[supreg] Excel files that are 
generated by the Microsoft[supreg] Access file. These files are 
provided on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/taconite-iron-ore-processing-national-emission-standards-hazardous.

VIII. Statutory and Executive Order Reviews

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

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

    This action is not a significant regulatory action and was, 
therefore, not submitted to OMB for review.

B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs

    This action is not expected to be an Executive Order 13771 
regulatory action because this action is not significant under 
Executive Order 12866.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to OMB under the PRA. The information 
collection request (ICR) document that the EPA prepared has been 
assigned EPA ICR number 2050.08. You can find a copy of the ICR in the 
docket for this rule, and it is briefly summarized here.
    We are proposing amendments that require electronic reporting, 
remove the malfunction exemption, and impose other revisions that 
affect reporting and recordkeeping for taconite iron ore processing 
facilities. This information would be collected to assure compliance 
with 40 CFR part 63, subpart RRRRR.
    Respondents/affected entities: Owners or operators of taconite iron 
ore processing facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart LLLLL).
    Estimated number of respondents: Eight (total).
    Frequency of response: Initial, semiannual, and annual.
    Total estimated burden: The annual recordkeeping and reporting 
burden for facilities to comply with all of the requirements in the 
NESHAP is estimated to be 1,000 hours (per year). Burden is defined at 
5 CFR 1320.3(b).
    Total estimated cost: The annual recordkeeping and reporting burden 
for facilities to comply with all of the requirements in the NESHAP is 
estimated to be $550,000 (per year). The only costs associated with the 
information collection activity is labor cost. There are no capital/
startup or operation and maintenance costs for this ICR.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to OIRA_submission@omb.eop.gov, Attention: Desk Officer for the 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after receipt, OMB must receive comments no 
later than October 25, 2019. The EPA will respond to any ICR-related 
comments in the final rule.

D. 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. Based on the 
Small Business Administration size category for this source category, 
no small entities are subject to this action.

E. Unfunded Mandates Reform Act (UMRA)

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

F. 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.

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

    This action does not have tribal implications as specified in 
Executive Order 13175. No tribal governments own facilities subject to 
this proposed action. Thus, Executive Order 13175 does not apply to 
this action. However, since tribal officials expressed significant 
interest in this rulemaking, consistent with the EPA Policy on 
Consultation and Coordination with Indian Tribes, a tribal consultation 
is planned for this rulemaking.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action, if finalized, would result in improved 
monitoring,

[[Page 50686]]

compliance, and implementation of the rule, which could lower the risk 
to all people affected by emissions from these facilities, including 
children. This action's health and risk assessments are contained in 
section IV of this preamble and in the Taconite Risk Report, which is 
available in the docket.

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

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA)

    This action involves technical standards. The EPA proposes to use 
ANSI/ASME PTC 19.10-1981 Part 10 (2010), ``Flue and Exhaust Gas 
Analyses,'' manual portion only, as an alternative to EPA Method 3B and 
incorporates the alternative method by reference. The ANSI/ASME PTC 
19.10-1981 Part 10 (2010) method incorporates both manual and 
instrumental methodologies for the determination of oxygen content of 
the exhaust gas. The manual method segment of the oxygen determination 
is performed through the absorption of oxygen. The method is acceptable 
as an alternative to EPA Method 3B and is available from the American 
Society of Mechanical Engineers (ASME) at http://www.asme.org; by mail 
at Three Park Avenue, New York, NY 10016-5990; or by telephone at (800) 
843-2763.

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations, and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994). To 
the extent that this action, if finalized, would result in improved 
monitoring, compliance, and implementation of the rule, we believe that 
it could decrease the risks posed by taconite iron ore processing 
facilities for these populations. This action's health and risk 
assessments are contained in section IV of this action. The 
documentation for this decision is contained in section IV.A.1 of this 
preamble and in the Taconite Risk Report, which is available in Docket 
ID No. EPA-HQ-OAR-2017-0664.

List of Subjects in 40 CFR Part 63

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

    Dated: August 28, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons set forth in the preamble, the EPA proposes to 
amend 40 CFR part 63 as follows:

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

0
1. The authority citation for part 63 continues to read as follows:

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

0
2. Section 63.14 is amended by revising paragraphs (e)(1) and (n)(3) to 
read as follows:

Sec.  63.14   Incorporations by reference.

* * * * *
    (e) * * *
    (1) ANSI/ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus], issued August 31, 1981, IBR approved 
for Sec. Sec.  63.309(k), 63.457(k), 63.772(e) and (h), 63.865(b), 
63.1282(d) and (g), 63.1625(b), 63.3166(a), 63.3360(e), 63.3545(a), 
63.3555(a), 63.4166(a), 63.4362(a), 63.4766(a), 63.4965(a), 63.5160(d), 
table 4 to subpart UUUU, 63.9307(c), 63.9323(a), 63.9621(b) and (c), 
63.11148(e), 63.11155(e), 63.11162(f), 63.11163(g), 63.11410(j), 
63.11551(a), 63.11646(a), and 63.11945, table 5 to subpart DDDDD, table 
4 to subpart JJJJJ, table 4 to subpart KKKKK, tables 4 and 5 of subpart 
UUUUU, table 1 to subpart ZZZZZ, and table 4 to subpart JJJJJJ.
* * * * *
    (n) * * *
    (3) EPA-454/R-98-015, Office of Air Quality Planning and Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance, September 1997, 
https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=2000D5T6.PDF, IBR approved 
for Sec. Sec.  63.548(e), 63.864(e), 63.7525(j), 63.8450(e), 
63.8600(e), 63.9632(a)(5), and 63.11224(f).
* * * * *

Subpart RRRRR--National Emission Standards for Hazardous Air 
Pollutants for the Taconite Iron Ore Processing

0
3. Section 63.9583 is revised to read as follows:

Sec.  63.9583   When do I have to comply with this subpart?

    (a) If you have an affected source the construction or 
reconstruction of which is commenced before December 18, 2002, 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 provided in paragraphs 
(f)(1) and (2) of this section.
    (b) If you have an affected source the construction or 
reconstruction of which is commenced on or after December 18, 2002, 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 noted in paragraphs (f)(1) and (2) 
of this section.
    (c) If you have an 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 noted 
in paragraphs (f)(1) and (2) 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, except as noted in paragraphs (f)(1) 
and (2) of this section.
    (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, except as noted in paragraphs (f)(1) and 
(2) of this section.
    (e) You must meet the notification and schedule requirements in 
Sec.  63.9640. Several of these notifications must be submitted before 
the compliance date for your affected source.
    (f)(1) If you have an affected source the construction or 
reconstruction of which is commenced before September 25, 2019, you 
must comply with the following requirements of this subpart by [DATE 
180 DAYS AFTER DATE OF PUBLICATION OF FINAL RULE IN THE FEDERAL 
REGISTER]: Sec.  63.9590(b)(2); Sec.  63.9600(a); Sec.  63.9610(a) 
introductory text; Sec.  63.9621(a); Sec.  63.9622(b) introductory 
text, (b)(1) and (2) and (d)(2); Sec.  63.9623(b)(2); Sec.  63.9631(c); 
Sec.  63.9632(a)(3); Sec.  63.9634(b)(3), (f) introductory text, and 
(f)(1), (3), and (4);

[[Page 50687]]

Sec.  63.9637; Sec.  63.9641(b)(7)(ii), (b)(8)(ii) and (iv), (c), (e), 
(g), (h), (i), and (j); Sec.  63.9642(a)(4), (5), and (6) and (b)(3); 
Sec.  63.9643(d); Table 2 to this subpart.
    (2) If you have an affected source the construction or 
reconstruction of which is commenced on or after September 25, 2019, 
you must comply with all the requirements of this subpart by [DATE OF 
PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] or the date of 
startup, whichever is later.
0
4. Section 63.9590 is amended by revising paragraph (b)(2) to read as 
follows:

Sec.  63.9590  What emission limitations must I meet?

* * * * *
    (b) * * *
    (2) 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 during the initial performance 
test.
* * * * *
0
5. Section 63.9600 is amended by revising paragraphs (a) and (b)(2) 
introductory text to read as follows:

Sec.  63.9600  What are my operation and maintenance requirements?

    (a) You must always operate and maintain any affected source, 
including associated air pollution control equipment and monitoring 
equipment, in a manner consistent with safety and good air pollution 
control practices for minimizing emissions. The general duty to 
minimize emissions does not require the owner or operator to make any 
further efforts to reduce emissions if levels required by the 
applicable standard have been achieved. Determination of whether such 
operation and maintenance procedures are being used will be based on 
information available to the Administrator which may include, but is 
not limited to, monitoring results, review of operation and maintenance 
procedures, review of operation and maintenance records, and inspection 
of the source.
    (b) * * *
    (2) Corrective action procedures for bag leak detection systems. In 
the event a bag leak detection system alarm is triggered, you must 
initiate corrective action to determine the cause of the alarm within 1 
hour of the alarm, initiate corrective action to correct the cause of 
the problem within 24 hours of the alarm, and complete the corrective 
action as soon as practicable. If the alarm sounds more than 5 percent 
of the operating time during a 6-month period as determined according 
to Sec.  63.9634(d)(3), it is considered an operating parameter 
deviation. Corrective actions may include, but are not limited to, the 
actions listed in paragraphs (b)(2)(i) through (vi) of this section.
* * * * *
0
6. Section 63.9610 is amended by revising paragraph (a) introductory 
text and removing and reserving paragraph (c) to read as follows:

Sec.  63.9610  What are my general requirements for complying with this 
subpart?

    (a) You must be in compliance with the requirements in paragraphs 
(a)(1) through (6) of this section at all times.
* * * * *
0
7. Section 63.9620 is amended by revising paragraph (f) introductory 
text and removing paragraph (f)(3) to read as follows:

Sec.  63.9620  On which units and by what date must I conduct 
performance tests or other initial compliance demonstrations?

* * * * *
    (f) If you elect to test representative emission units as provided 
in paragraph (e) of this section, the units that are grouped together 
as similar units must meet the criteria in paragraphs (f)(1) and (2) of 
this section.
* * * * *
0
8. Section 63.9621 is amended by revising paragraphs (a), (b)(1) and 
(2), and (c)(1) and (2) to read as follows:

Sec.  63.9621  What test methods and other procedures must I use to 
demonstrate initial compliance with the emission limits for particulate 
matter?

    (a) You must conduct each performance test that applies to your 
affected source under normal maximum 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.
    (b) * * *
    (1) Except as provided in Sec.  63.9620(e), determine the 
concentration of particulate matter in the stack gas for each emission 
unit according to the test methods listed in paragraphs (b)(1)(i) 
through (v) of this section.
    (i) Method 1 or 1A in appendix A-1 to part 60 of this chapter to 
select sampling port locations and the number of traverse points. 
Sampling ports must be located at the outlet of the control device and 
prior to any releases to the atmosphere.
    (ii) Method 2, 2A, 2C, 2D, or 2F in appendix A-1 to part 60 of this 
chapter or Method 2G in appendix A-2 to part 60 of this chapter, as 
applicable, to determine the volumetric flow rate of the stack gas.
    (iii) Method 3A or 3B in appendix A-2 to part 60 of this chapter to 
determine the dry molecular weight of the stack gas. The voluntary 
consensus standard ANSI/ASME PTC 19.10-1981--Part 10 (incorporated by 
reference--see Sec.  63.14) may be used as an alternative to the manual 
procedures (but not instrumental procedures) in Method 3B.
    (iv) Method 4 in appendix A-3 to part 60 of this chapter to 
determine the moisture content of the stack gas.
    (v) Method 5 or 5D in appendix A-3 to part 60 of this chapter or 
Method 17 in appendix A-6 to part 60 of this chapter to determine the 
concentration of particulate matter.
    (2) Each Method 5, 5D, or 17 performance test must consist of three 
separate runs. Each run must be conducted for a minimum of 1 hour. If 
any measurement result is reported as below the method detection limit, 
use the method detection limit for that value when calculating the 
average particulate matter concentration. The average particulate 
matter concentration from the three runs will be used to determine 
compliance, as shown in Equation 1 of this section.
[GRAPHIC] [TIFF OMITTED] TP25SE19.004

[[Page 50688]]

Where:

Ci = Average particulate matter concentration for 
emission unit, grains per dry standard cubic foot, (gr/dscf);
C1 = Particulate matter concentration for run 1 
corresponding to emission unit, gr/dscf;
C2 = Particulate matter concentration for run 2 
corresponding to emission unit, gr/dscf; and
C3 = Particulate matter concentration for run 3 
corresponding to emission unit, gr/dscf.
* * * * *

    (c) * * *
    (1) Determine the concentration of particulate matter for each 
stack according to the test methods listed in paragraphs (c)(1)(i) 
through (v) of this section.
    (i) Method 1 or 1A in appendix A-1 to part 60 of this chapter to 
select sampling port locations and the number of traverse points. 
Sampling ports must be located at the outlet of the control device and 
prior to any releases to the atmosphere.
    (ii) Method 2, 2A, 2C, 2D, or 2F in appendix A-1 to part 60 of this 
chapter or Method 2G in appendix A-2 to part 60 of this chapter, as 
applicable, to determine the volumetric flow rate of the stack gas.
    (iii) Method 3A or 3B in appendix A-2 to part 60 of this chapter to 
determine the dry molecular weight of the stack gas. The voluntary 
consensus standard ANSI/ASME PTC 19.10-1981--Part 10 (incorporated by 
reference--see Sec.  63.14) may be used as an alternative to the manual 
procedures (but not instrumental procedures) in Method 3B.
    (iv) Method 4 in appendix A-3 to part 60 of this chapter to 
determine the moisture content of the stack gas.
    (v) Method 5 or 5D in appendix A-3 to part 60 of this chapter to 
determine the concentration of particulate matter.
    (2) Each Method 5 or 5D performance test must consist of three 
separate runs. Each run must be conducted for a minimum of 1 hour. If 
any measurement result is reported as below the method detection limit, 
use the method detection limit for that value when calculating the 
average particulate matter concentration. The average particulate 
matter concentration from the three runs will be used to determine 
compliance, as shown in Equation 1 of this section.
* * * * *
0
9. Section 63.9622 is amended by revising paragraphs (b) and (d)(2) to 
read as follows:

Sec.  63.9622  What test methods and other procedures must I use to 
establish and demonstrate initial compliance with the operating limits?

* * * * *
    (b) For dynamic wet scrubbers subject to performance testing in 
Sec.  63.9620 and operating limits for scrubber water flow rate and fan 
amperage in Sec.  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) Using the CPMS required in Sec.  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) 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.
* * * * *
    (d) * * *
    (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 electrostatic precipitator 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.
* * * * *
0
10. Section 63.9623 is amended by revising paragraph (b)(2) to read as 
follows:

Sec.  63.9623  How do I demonstrate initial compliance with the 
emission limitations that apply to me?

* * * * *
    (b) * * *
    (2) For each dynamic wet scrubber subject to performance testing in 
Sec.  63.9620 and operating limits for scrubber water flow rate and fan 
amperage in Sec.  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 Sec.  63.9622(b).
* * * * *
0
11. Section 63.9625 is amended by revising the introductory text to 
read as follows:

Sec.  63.9625  How do I demonstrate initial compliance with the 
operation and maintenance requirements that apply to me?

    For each air pollution control device subject to operating limits 
in Sec.  63.9590(b), you have demonstrated initial compliance with the 
operation and maintenance requirements if you meet all of the 
requirements in paragraphs (a) through (d) of this section.
* * * * *
0
12. Section 63.9631 is amended by revising paragraphs (a) introductory 
text and (c) to read as follows:

Sec.  63.9631  What are my monitoring requirements?

    (a) For each baghouse applied to meet any particulate matter 
emission limit in Table 1 to this subpart, you must install, operate, 
and maintain a bag leak detection system to monitor the relative change 
in particulate matter loadings according to the requirements in Sec.  
63.9632(a), and conduct inspections at their specified frequencies 
according to the requirements in paragraphs (a)(1) through (6) and (8) 
of this section. For each baghouse applied to meet any particulate 
matter emission limit in Table 1 to this subpart that is not required 
by Sec.  63.9632(a) to be equipped with a bag leak detection system, 
you must conduct inspections at their specified frequencies according 
to the requirements in paragraphs (a)(1) through (8) of this section.
* * * * *
    (c) For each dynamic wet scrubber subject to the scrubber water 
flow rate and the fan amperage operating limits in Sec.  63.9590(b)(2), 
you must install, operate, and maintain a CPMS according to the 
requirements in Sec.  63.9632(b) through (e) and monitor the daily 
average scrubber water flow rate and the daily average fan amperage 
according to the requirements in Sec.  63.9633.
* * * * *
0
13. Section 63.9632 is amended by:
0
a. Revising paragraphs (a) introductory text and (a)(1).
0
b. Redesignating paragraphs (a)(3) through (8) as paragraphs (a)(4) 
through (9).
0
c. Adding new paragraph (a)(3).
0
d. Revising newly redesignated paragraphs (a)(4), (a)(5) introductory 
text, (a)(7) introductory text, and (a)(7)(i).
0
e. Revising paragraphs (b)(3) through (6) and (f)(2) and (4).
    The revisions and addition read as follows:

[[Page 50689]]

Sec.  63.9632  What are the installation, operation, and maintenance 
requirements for my monitoring equipment?

    (a) For each negative pressure baghouse or positive pressure 
baghouse equipped with a stack, applied to meet any particulate 
emission limit in Table 1 to this subpart, you must install, operate, 
and maintain a bag leak detection system for each exhaust stack 
according to the requirements in paragraphs (a)(1) through (9) of this 
section.
    (1) A bag leak detection system installed before September 25, 
2019, must be certified by the manufacturer to be capable of detecting 
emissions of particulate matter at concentrations of 10 milligrams per 
actual cubic meter (0.0044 grains per actual cubic foot) or less. A bag 
leak detection system installed after September 25, 2019, must be 
certified by the manufacturer to be capable of detecting emissions of 
particulate matter at concentrations of 1 milligram per actual cubic 
meter (0.00044 grains per actual cubic foot) or less.
* * * * *
    (3) The bag leak detection system must be equipped with a device to 
continuously record the output signal from the sensor.
    (4) The system must be equipped with an alarm that will sound when 
an increase in relative particulate loadings is detected over the alarm 
level set point established according to paragraph (a)(5) of this 
section. The alarm must be located such that it can be heard by the 
appropriate plant personnel.
    (5) For each bag leak detection system, you must develop and submit 
to the Administrator for approval, a site-specific monitoring plan that 
addresses the items identified in paragraphs (a)(5)(i) through (v) of 
this section. The monitoring plan shall be consistent with the 
manufacturer's specifications and recommendations contained in the U.S. 
Environmental Protection Agency (U.S. EPA) guidance document, ``Fabric 
Filter Bag Leak Detection Guidance'' (EPA-454/R-98-015) (incorporated 
by reference--see Sec.  63.14). You must operate and maintain the bag 
leak detection system according to the site-specific monitoring plan at 
all times. The plan shall describe all of the items in paragraphs 
(a)(5)(i) through (v) of this section.
* * * * *
    (7) Following initial adjustment, do not adjust sensitivity or 
range, averaging period, alarm set point, or alarm delay time, without 
approval from the Administrator except as provided for in paragraph 
(a)(7)(i) of this section. In no event may the sensitivity be increased 
more than 100 percent or decreased by more than 50 percent over a 365-
day period unless such adjustment follows a complete baghouse 
inspection that demonstrates the baghouse is in good operating 
condition.
    (i) Once per quarter, you may adjust the sensitivity or range of 
the bag leak detection system to account for seasonal effects, 
including temperature and humidity, according to the procedures 
identified in the site-specific monitoring plan required under 
paragraph (a)(5) of this section.
* * * * *
    (b) * * *
    (3) Performance evaluation procedures, a schedule for performing 
such procedures, and acceptance criteria (e.g., calibrations), as well 
as corrective action to be taken if a performance evaluation does not 
meet the acceptance criteria. If a CPMS calibration fails, the CPMS is 
considered to be inoperative until you take corrective action and the 
system passes calibration.
    (4) Ongoing operation and maintenance procedures and a schedule for 
preventative maintenance procedures, in a manner consistent with good 
air pollution control practices and in accordance with the general 
requirements of Sec.  63.8(c)(1)(ii), (c)(3), (c)(4)(ii), and (c)(7) 
and (8).
    (5) Ongoing data quality assurance procedures in accordance with 
the general requirements of Sec.  63.8(d)(1) and (2). The owner or 
operator shall keep these written procedures on record for the life of 
the affected source or until the affected source is no longer subject 
to the provisions of this part, to be made available for inspection, 
upon request, by the Administrator. If the performance evaluation plan 
is revised, the owner or operator shall keep previous (i.e., 
superseded) versions of the performance evaluation plan on record to be 
made available for inspection, upon request, by the Administrator, for 
a period of 5 years after each revision to the plan.
    (6) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c)(1) through (14), 
(e)(1), and (e)(2)(i).
* * * * *
    (f) * * *
    (2) You must develop and implement a quality control program for 
operating and maintaining each COMS according to Sec.  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.
* * * * *
    (4) You must determine and record the 6-minute average opacity for 
periods during which the COMS is not out of control. All COMS must 
complete a minimum of one cycle of sampling and analyzing for each 
successive 10-second period and one cycle of data recording for each 
successive 6-minute period.
0
14. Section 63.9633 is amended by revising paragraphs (a) and (b) to 
read as follows:

Sec.  63.9633  How do I monitor and collect data to demonstrate 
continuous compliance?

    (a) Except for monitoring malfunctions, out of control periods, 
associated repairs, and required quality assurance or control 
activities (including as applicable, calibration checks and required 
zero and span adjustments), you must monitor continuously (or collect 
data at all required intervals) at all times an affected source is 
operating.
    (b) You may not use data recorded during monitoring malfunctions, 
out of control periods, associated repairs, and required quality 
assurance or control activities in data averages and calculations used 
to report emission or operating levels, or to fulfill a minimum data 
availability requirement. You must use all the data collected during 
all other periods in assessing compliance.
* * * * *
0
15. Section 63.9634 is amended by:
0
a. Revising paragraphs (b)(3), (d) introductory text, and (d)(2).
0
b. Adding paragraph (d)(3).
0
c. Revising paragraphs (f) introductory text, (f)(1), (3), and (4), 
(h)(1), and (j)(1) and (2).
    The revisions and addition read as follows:

Sec.  63.9634  How do I demonstrate continuous compliance with the 
emission limitations that apply to me?

* * * * *
    (b) * * *
    (3) For ore crushing and handling and finished pellet handling 
emission units not selected for initial performance testing and defined 
within a group of similar emission units in accordance with Sec.  
63.9620(e), the site-specific operating limits established for the 
emission unit selected as representative of a group of similar emission 
units will be used as the operating limit for each emission unit within 
the group. The operating limit established for the representative unit 
must be met by each emission unit within the group.
* * * * *

[[Page 50690]]

    (d) For each baghouse applied to meet any particulate emission 
limit in Table 1 to this subpart, you must demonstrate continuous 
compliance by completing the requirements in paragraphs (d)(1) through 
(3) of this section.
* * * * *
    (2) Inspecting and maintaining each baghouse according to the 
requirements in Sec.  63.9631(a) and recording all information needed 
to document conformance with the requirements in Sec.  63.9631(a). If 
you increase or decrease the sensitivity of the bag leak detection 
system beyond the limits specified in your site-specific monitoring 
plan, you must include a copy of the required written certification by 
a responsible official in the next semiannual compliance report.
    (3) Each bag leak detection system must be operated and maintained 
such that the alarm does not sound more than 5 percent of the operating 
time during a 6-month period. Calculate the alarm time as specified in 
paragraphs (d)(3)(i) through (iii) of this section.
    (i) If inspection of the fabric filter demonstrates that no 
corrective action is required, no alarm time is counted.
    (ii) If corrective action is required, each alarm time (i.e., time 
that the alarm sounds) is counted as a minimum of 1 hour.
    (iii) If it takes longer than 1 hour to initiate corrective action, 
each alarm time is counted as the actual amount of time taken to 
initiate corrective action.
* * * * *
    (f) For each dynamic wet scrubber subject to the operating limits 
for scrubber water flow rate and the fan amperage in Sec.  
63.9590(b)(2), you must demonstrate continuous compliance by completing 
the requirements of paragraphs (f)(1) through (4) of this section.
    (1) Maintaining the daily average scrubber water flow rate and the 
daily average fan amperage at or above the minimum levels established 
during the initial or subsequent performance test.
* * * * *
    (3) Collecting and reducing monitoring data for scrubber water flow 
rate and fan amperage according to Sec.  63.9632(c) and recording all 
information needed to document conformance with the requirements in 
Sec.  63.9632(c).
    (4) 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 (j) of 
this section.
* * * * *
    (h) * * *
    (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.
* * * * *
    (j) * * *
    (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 (j)(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.
* * * * *
0
16. Section 63.9637 is revised to read as follows:

Sec.  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 Table 1 to this subpart that applies 
to you. You also must report each instance in which you did not meet 
the work practice standards in Sec.  63.9591 and each instance in which 
you did not meet each operation and maintenance requirement in Sec.  
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 Sec.  63.9641.
    (b) [Reserved]
0
17. Section 63.9640 is amended by revising paragraph (e)(2) to read as 
follows:

Sec.  63.9640   What notifications must I submit and when?

* * * * *
    (e) * * *
    (2) For each initial compliance demonstration that does include a 
performance test, you must submit the notification of compliance 
status, including the performance test results, before the close of 
business on the 60th calendar day following the completion of the 
performance test according to Sec.  63.10(d)(2). If the performance 
test results have been submitted electronically in accordance with 
Sec.  63.9641(f), the process unit(s) tested, the pollutant(s) tested, 
and the date that such performance test was conducted may be submitted 
in the notification of compliance status report in lieu of the 
performance test results. The performance test results must be 
submitted to the Compliance and Emissions Data Reporting Interface 
(CEDRI) by the date the notification of compliance status report is 
submitted.
0
18. Section 63.9641 is amended by:
0
a. Revising paragraphs (a)(2) and (4), (b) introductory text, and 
(b)(2) and (3).
0
b. Removing and reserving paragraph (b)(4).
0
c. Revising paragraphs (b)(7), (b)(8) introductory text, (b)(8)(ii) 
through (vii) and (b)(8)(ix), and (c).
0
d. Adding paragraphs (f), (g), and (h).
    The revisions and additions read as follows:

Sec.  63.9641  What reports must I submit and when?

    (a) * * *
    (2) The first compliance report must be electronically submitted, 
postmarked or delivered no later than July 31 or January 31, whichever 
date comes first after your first compliance report is due.
* * * * *
    (4) Each subsequent compliance report must be electronically 
submitted, postmarked or delivered no later than July 31 or January 31, 
whichever date comes first after the end of the semiannual reporting 
period.
* * * * *

[[Page 50691]]

    (b) Compliance report contents. Each compliance report must include 
the information in paragraphs (b)(1) through (8) of this section, as 
applicable.
* * * * *
    (2) Statement by a responsible official, with the official's name, 
title, and signature, certifying the truth, accuracy, and completeness 
of the content of the report. If your report is submitted via CEDRI, 
the certifier's electronic signature during the submission process 
replaces the requirement in this paragraph (b)(2).
    (3) Date of report and beginning and ending dates of the reporting 
period. You are no longer required to provide the date of report when 
the report is submitted via CEDRI.
* * * * *
    (7) For each deviation from an emission limitation in Table 1 to 
this subpart that occurs at an affected source where you are not using 
a continuous monitoring system (including a CPMS or COMS) to comply 
with an emission limitation in this subpart, the compliance report must 
contain the information in paragraphs (b)(7)(i) and (ii) of this 
section.
    (i) The total operating time in hours of each affected source 
during the reporting period.
    (ii) Information on the affected sources or equipment, the emission 
limited deviation from, the start date, start time, duration in hours, 
and cause of each deviation (including unknown cause) as applicable, an 
estimate of the quantity in pounds of each regulated pollutant emitted 
over an emission limit and a description of the method used to estimate 
the emissions, and the corrective action taken.
    (8) 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.
* * * * *
    (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 in hours (or minutes 
for COMS) that each continuous monitoring system was out-of-control, 
including the information in Sec.  63.8(c)(8).
    (iv) For each affected source or equipment, the date, the 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 in hours (or minutes for COMS) of all 
deviations for each 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) A breakdown of the total duration in hours (or minutes for 
COMS) 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 in hours (or minutes for COMS) 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.
* * * * *
    (ix) The monitoring equipment manufacturer and model number and the 
pollutant or parameter monitored.
* * * * *
    (c) Submitting compliance reports electronically. Beginning on 
[DATE 180 DAYS AFTER DATE OF PUBLICATION OF FINAL RULE IN THE FEDERAL 
REGISTER], 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/). You must use the appropriate electronic 
report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-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. If you claim some of the information required 
to be submitted via CEDRI is confidential business information (CBI), 
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. Submit the file on a compact disc, flash drive, or other 
commonly used electronic storage medium and clearly mark the medium as 
CBI. Mail the electronic medium to U.S. EPA/OAQPS/SPPD/CORE CBI Office, 
Attention: Taconite Iron Ore Processing Sector Lead, MD C404-02, 4930 
Old Page Rd., Durham, NC 27703. 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).
* * * * *
    (f) Performance tests. Within 60 days after the date of completing 
each performance test required by this subpart, you must submit the 
results of the performance test following the procedures specified in 
paragraphs (f)(1) through (3) of this section.
    (1) Data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT website 
(https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. Submit the results of the 
performance test to the EPA via CEDRI, which can be accessed through 
the EPA's CDX (https://cdx.epa.gov/). The data must be submitted in a 
file format generated through the use of the EPA's ERT. Alternatively, 
you may submit an electronic file consistent with the extensible markup 
language (XML) schema listed on the EPA's ERT website.
    (2) Data collected using test methods that are not supported by the 
EPA's ERT as listed on the EPA's ERT website at the time of the test. 
The results of the performance test must be included as an attachment 
in the ERT or an alternate electronic file consistent with the XML 
schema listed on the EPA's ERT website. Submit the ERT generated 
package or alternative file to the EPA via CEDRI.
    (3) Confidential business information (CBI). If you claim some of 
the information submitted under paragraph (f)(1) or (2) of this section 
is CBI, you must submit a complete file, including information claimed 
to be CBI, to the EPA. The file must be 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. Submit the file on a compact 
disc, flash drive, or other commonly used electronic storage medium and 
clearly mark the medium as CBI. Mail the electronic medium 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 file 
with the CBI omitted must be submitted to the EPA via the EPA's CDX as 
described in paragraphs (f)(1) and (2) of this section.
    (g) Claims of EPA system outage. If you are required to 
electronically submit a report through CEDRI in the EPA's CDX, you may 
assert a claim of

[[Page 50692]]

EPA system outage for failure to timely comply with the reporting 
requirement. To assert a claim of EPA system outage, you must meet the 
requirements outlined in paragraphs (g)(1) through (7) of this section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) Measures taken or to be taken to minimize the delay in 
reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (h) Claims of force majeure. If you are required to electronically 
submit a report through CEDRI in the EPA's CDX, you may assert a claim 
of force majeure for failure to timely comply with the reporting 
requirement. To assert a claim of force majeure, you must meet the 
requirements outlined in paragraphs (h)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this section, a 
force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) Measures taken or to be taken to minimize the delay in 
reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
0
19. Section 63.9642 is amended by:
0
a. Revising paragraph (a) introductory text.
0
b. Removing and reserving paragraph (a)(2).
0
c. Adding paragraphs (a)(4) through (6).
0
d. Revising paragraph (b)(3).
    The revisions and additions read as follows:

Sec.  63.9642  What records must I keep?

    (a) You must keep the records listed in paragraphs (a)(1) through 
(6) of this section.
* * * * *
    (4) In the event that an affected unit fails to meet an applicable 
standard, record the number of failures. For each failure record the 
date, time, the cause and duration of each failure.
    (5) For each failure to meet an applicable standard, record and 
retain a list of the affected sources or equipment, an estimate of the 
quantity of each regulated pollutant emitted over any emission limit 
and a description of the method used to estimate the emissions.
    (6) Record actions taken in accordance with the general duty 
requirements to minimize emissions in Sec.  63.9600(a) and any 
corrective actions taken to return the affected unit to its normal or 
usual manner of operation.
    (b) * * *
    (3) Previous (that is, superseded) versions of the performance 
evaluation plan as required in Sec.  63.9632(b)(5), with the program of 
corrective action included in the plan required under Sec.  63.8(d)(2).
* * * * *
0
20. Section 63.9650 is revised to read as follows:

Sec.  63.9650  What parts of the General Provisions apply to me?

    Table 2 to this subpart shows which parts of the General Provisions 
in Sec. Sec.  63.1 through 63.16 apply to you.
0
21. Section 63.9651 is amended by revising paragraph (c) introductory 
text and adding paragraph (c)(5) to read as follows:

Sec.  63.9651  Who implements and enforces this subpart?

* * * * *
    (c) The authorities that will not be delegated to State, local, or 
tribal agencies are specified in paragraphs (c)(1) through (5) of this 
section.
* * * * *
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.
0
22. Section 63.9652 is amended by:
0
a. Removing the definition of ``Conveyor belt transfer point''.
0
b. Revising the definition of ``Deviation''.
0
c. Removing the definition of ``Wet grinding and milling''.
0
d. Adding the definition of ``Wet scrubber''.
    The revision and addition read as follows:

Sec.  63.9652  What definitions apply to this subpart?

* * * * *
    Deviation means any instance in which an affected source subject to 
this subpart, or an owner or operator of such a source:
    (1) Fails to meet any requirement or obligation established by this 
subpart, including but not limited to any emission limitation 
(including operating limits) or operation and maintenance requirement; 
or
    (2) Fails to meet any term or condition that is adopted to 
implement an applicable requirement in this subpart and that is 
included in the operating permit for any affected source required to 
obtain such a permit.
* * * * *
    Wet scrubber means an air pollution control device that removes 
particulate matter and acid gases from the waste gas stream of 
stationary sources. The pollutants are removed primarily

[[Page 50693]]

through the impaction, diffusion, interception and/or absorption of the 
pollutant onto droplets of liquid. Wet scrubbers include venturi 
scrubbers, marble bed scrubbers, or impingement scrubbers. For purposes 
of this subpart, wet scrubbers do not include dynamic wet scrubbers.
0
23. Table 2 to subpart RRRRR of part 63 is revised to read as follows:
    As required in Sec.  63.9650, you must comply with the requirements 
of the NESHAP General Provisions (40 CFR part 63, subpart A) shown in 
the following table:

      Table 2 to Subpart RRRRR of Part 63--Applicability of General Provisions to Subpart RRRRR of Part 63
----------------------------------------------------------------------------------------------------------------
                                                               Applies to subpart
              Citation                       Subject                  RRRRR                  Explanation
----------------------------------------------------------------------------------------------------------------
Sec.   63.1(a)(1)-(4)..............  Applicability.........  Yes.                    ...........................
Sec.   63.1(a)(5)..................  [Reserved]............  No.                     ...........................
Sec.   63.1(a)(6)..................  Applicability.........  Yes.                    ...........................
Sec.   63.1(a)(7)-(9)..............  [Reserved]............  No.                     ...........................
Sec.   63.1(a)(10)-(12)............  Applicability.........  Yes.                    ...........................
Sec.   63.1(b)(1)..................  Initial Applicability   Yes.                    ...........................
                                      Determination.
Sec.   63.1(b)(2)..................  [Reserved]............  No.                     ...........................
Sec.   63.1(b)(3)..................  Initial Applicability   Yes.                    ...........................
                                      Determination.
Sec.   63.1(c)(1)-(2)..............  Applicability After     Yes.                    ...........................
                                      Standard Established,
                                      Permit Requirements.
Sec.   63.1(c)(3)-(4)..............  [Reserved]............  No.                     ...........................
Sec.   63.1(c)(5)..................  Area Source Becomes     Yes.                    ...........................
                                      Major.
Sec.   63.1(d).....................  [Reserved]............  No.                     ...........................
Sec.   63.1(e).....................  Equivalency of Permit   Yes.                    ...........................
                                      Limits.
Sec.   63.2........................  Definitions...........  Yes.                    ...........................
Sec.   63.3(a)-(c).................  Units and               Yes.                    ...........................
                                      Abbreviations.
Sec.   63.4(a)(1)-(2)..............  Prohibited Activities.  Yes.                    ...........................
Sec.   63.4(a)(3)-(5)..............  [Reserved]............  No.                     ...........................
Sec.   63.4(b)-(c).................  Circumvention,          Yes.                    ...........................
                                      Fragmentation.
Sec.   63.5(a)(1)-(2)..............  Construction/           Yes.                    ...........................
                                      Reconstruction,
                                      Applicability.
Sec.   63.5(b)(1)..................  Construction/           Yes.                    ...........................
                                      Reconstruction,
                                      Applicability.
Sec.   63.5(b)(2)..................  [Reserved]............  No.                     ...........................
Sec.   63.5(b)(3)-(4)..............  Construction/           Yes.                    ...........................
                                      Reconstruction,
                                      Applicability.
Sec.   63.5(b)(5)..................  [Reserved]............  No.                     ...........................
Sec.   63.5(b)(6)..................  Applicability.........  Yes.                    ...........................
Sec.   63.5(c).....................  [Reserved]............  No.                     ...........................
Sec.   63.5(d)(1)-(4)..............  Application for         Yes.                    ...........................
                                      Approval of
                                      Construction or
                                      Reconstruction.
Sec.   63.5(e).....................  Approval of             Yes.                    ...........................
                                      Construction or
                                      Reconstruction.
Sec.   63.5(f).....................  Approval Based on       Yes.                    ...........................
                                      State Review.
Sec.   63.6(a).....................  Compliance with         Yes.                    ...........................
                                      Standards and
                                      Maintenance
                                      Requirements.
Sec.   63.6(b)(1)-(5)..............  Compliance Dates for    Yes.                    ...........................
                                      New/Reconstructed
                                      Sources.
Sec.   63.6(b)(6)..................  [Reserved]............  No.                     ...........................
Sec.   63.6(b)(7)..................  Compliance Dates for    Yes.                    ...........................
                                      New/Reconstructed
                                      Sources.
Sec.   63.6(c)(1)-(2)..............  Compliance Dates for    Yes.                    ...........................
                                      Existing Sources.
Sec.   63.6(c)(3)-(4)..............  [Reserved]............  No.                     ...........................
Sec.   63.6(c)(5)..................  Compliance Dates for    Yes.                    ...........................
                                      Existing Sources.
Sec.   63.6(d).....................  [Reserved]............  No.                     ...........................
Sec.   63.6(e)(1)(i)...............  Operation and           No....................  See Sec.   63.9600(a) for
                                      Maintenance                                     general duty requirement.
                                      Requirements--General
                                      Duty to Minimize
                                      Emissions.
Sec.   63.6(e)(1)(ii)..............  Operation and           No.                     ...........................
                                      Maintenance
                                      Requirements--Require
                                      ment to Correct
                                      Malfunction as Soon
                                      as Possible.
Sec.   63.6(e)(1)(iii).............  Operation and           Yes.                    ...........................
                                      Maintenance
                                      Requirements--Enforce
                                      ability.
Sec.   63.6(e)(2)..................  [Reserved]............  No.                     ...........................
Sec.   63.6(e)(3)..................  Startup, Shutdown,      No.                     ...........................
                                      Malfunction (SSM)
                                      Plan.
Sec.   63.6(f)(1)..................  SSM Exemption.........  No.                     ...........................
Sec.   63.6(f)(2)-(3)..............  Methods for             Yes.                    ...........................
                                      Determining
                                      Compliance.
Sec.   63.6(g)(1)-(3)..............  Alternative Nonopacity  Yes.                    ...........................
                                      Standard.
Sec.   63.6(h).....................  Compliance with         No....................  Opacity limits in subpart
                                      Opacity and Visible                             RRRRR are established as
                                      Emission (VE)                                   part of performance
                                      Standards.                                      testing in order to set
                                                                                      operating limits for ESPs.
Sec.   63.6(i)(1)-(14).............  Extension of            Yes.                    ...........................
                                      Compliance.

[[Page 50694]]

 
Sec.   63.6(i)(15).................  [Reserved]............  No.                     ...........................
Sec.   63.6(i)(16).................  Extension of            Yes.                    ...........................
                                      Compliance.
Sec.   63.6(j).....................  Presidential            Yes.                    ...........................
                                      Compliance Exemption.
Sec.   63.7(a)(1)-(2)..............  Applicability and       No....................  Subpart RRRRR specifies
                                      Performance Test                                performance test
                                      Dates.                                          applicability and dates.
Sec.   63.7(a)(3)-(4)..............  Performance Testing     Yes.                    ...........................
                                      Requirements.
Sec.   63.7(b).....................  Notification..........  Yes.                    ...........................
Sec.   63.7(c).....................  Quality Assurance/Test  Yes.                    ...........................
                                      Plan.
Sec.   63.7(d).....................  Testing Facilities....  Yes.                    ...........................
Sec.   63.7(e)(1)..................  Conduct of Performance  No....................  See Sec.   63.9621.
                                      Tests.
Sec.   63.7(e)(2)-(4)..............  Conduct of Performance  Yes.                    ...........................
                                      Tests.
Sec.   63.7(f).....................  Alternative Test        Yes.                    ...........................
                                      Method.
Sec.   63.7(g).....................  Data Analysis.........  Yes...................  Except this subpart
                                                                                      specifies how and when the
                                                                                      performance test results
                                                                                      are reported.
Sec.   63.7(h).....................  Waiver of Tests.......  Yes.                    ...........................
Sec.   63.8(a)(1)-(2)..............  Monitoring              Yes.                    ...........................
                                      Requirements.
Sec.   63.8(a)(3)..................  [Reserved]............  No.                     ...........................
Sec.   63.8(a)(4)..................  Additional Monitoring   No....................  Subpart RRRRR does not
                                      Requirements for                                require flares.
                                      Control Devices in
                                      Sec.   63.11.
Sec.   63.8(b)(1)-(3)..............  Conduct of Monitoring.  Yes.                    ...........................
Sec.   63.8(c)(1)(i)...............  Operation and           No....................  See Sec.   63.9632 for
                                      Maintenance of CMS.                             operation and maintenance
                                                                                      requirements for
                                                                                      monitoring. See Sec.
                                                                                      63.9600(a) for general
                                                                                      duty requirement.
Sec.   63.8(c)(1)(ii)..............  Spare parts for CMS     Yes.                    ...........................
                                      Equipment.
Sec.   63.8(c)(1)(iii).............  SSM Plan for CMS......  No.                     ...........................
Sec.   63.8(c)(2)-(3)..............  CMS Operation/          Yes.                    ...........................
                                      Maintenance.
Sec.   63.8(c)(4)..................  Frequency of Operation  No....................  Subpart RRRRR specifies
                                      for CMS.                                        requirements for operation
                                                                                      of CMS.
Sec.   63.8(c)(5)-(8)..............  CMS Requirements......  Yes...................  CMS requirements in Sec.
                                                                                      63.8(c)(5) and (6) apply
                                                                                      only to COMS for dry
                                                                                      electrostatic
                                                                                      precipitators.
Sec.   63.8(d)(1)-(2)..............  Monitoring Quality      Yes.                    ...........................
                                      Control.
Sec.   63.8(d)(3)..................  Monitoring Quality      No....................  See Sec.   63.9632(b)(5).
                                      Control.
Sec.   63.8(e).....................  Performance Evaluation  Yes.                    ...........................
                                      of CMS.
Sec.   63.8(f)(1)-(5)..............  Alternative Monitoring  Yes.                    ...........................
                                      Method.
Sec.   63.8(f)(6)..................  Relative Accuracy Test  No....................  Subpart RRRRR does not
                                      Alternative (RATA).                             require continuous
                                                                                      emission monitoring
                                                                                      systems.
Sec.   63.8(g)(1)-(4)..............  Data Reduction........  Yes.                    ...........................
Sec.   63.8(g)(5)..................  Data That Cannot Be     No....................  Subpart RRRRR specifies
                                      Used.                                           data reduction
                                                                                      requirements.
Sec.   63.9........................  Notification            Yes...................  Additional notifications
                                      Requirements.                                   for CMS in Sec.   63.9(g)
                                                                                      apply to COMS for dry
                                                                                      electrostatic
                                                                                      precipitators.
Sec.   63.10(a)....................  Recordkeeping and       Yes.                    ...........................
                                      Reporting,
                                      Applicability and
                                      General Information.
Sec.   63.10(b)(1).................  General Recordkeeping   Yes.                    ...........................
                                      Requirements.
Sec.   63.10(b)(2)(i)..............  Records of SSM........  No....................  See Sec.   63.9642 for
                                                                                      recordkeeping when there
                                                                                      is a deviation from a
                                                                                      standard.
Sec.   63.10(b)(2)(ii).............  Recordkeeping of        No....................  See Sec.   63.9642 for
                                      Failures to Meet                                recordkeeping of (1) date,
                                      Standard.                                       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.
Sec.   63.10(b)(2)(iii)............  Maintenance Records...  Yes.                    ...........................
Sec.   63.10(b)(2)(iv).............  Actions Taken to        No.                     ...........................
                                      Minimize Emissions
                                      During SSM.
Sec.   63.10(b)(2)(v)..............  Actions Taken to        No.                     ...........................
                                      Minimize Emissions
                                      During SSM.
Sec.   63.10(b)(2)(vi).............  Recordkeeping for CMS   Yes.                    ...........................
                                      Malfunctions.
Sec.   63.10(b)(2)(vii)-(xii)......  Recordkeeping for CMS.  Yes.                    ...........................
Sec.   63.10(b)(2)(xiii)...........  Records for Relative    No....................  Subpart RRRRR does not
                                      Accuracy Test.                                  require continuous
                                                                                      emission monitoring
                                                                                      systems.
Sec.   63.10(b)(2)(xiv)............  Records for             Yes.                    ...........................
                                      Notification.
Sec.   63.10(b)(3).................  Applicability           Yes.                    ...........................
                                      Determinations.
Sec.   63.10(c)(1)-(6).............  Additional              Yes.                    ...........................
                                      Recordkeeping
                                      Requirements for
                                      Sources with CMS.
Sec.   63.10(c)(7)-(8).............  Records of Excess       No....................  Subpart RRRRR specifies
                                      Emissions and                                   recordkeeping
                                      Parameter Monitoring                            requirements.
                                      Exceedances for CMS.
Sec.   63.10(c)(9).................  [Reserved]............  No.                     ...........................

[[Page 50695]]

 
Sec.   63.10(c)(10)-(14)...........  CMS Recordkeeping.....  Yes                     ...........................
Sec.   63.10(c)(15)................  Use of SSM Plan.......  No.                     ...........................
Sec.   63.10(d)(1)-(2).............  General Reporting       Yes...................  Except this subpart
                                      Requirements.                                   specifies how and when the
                                                                                      performance test results
                                                                                      are reported.
Sec.   63.10(d)(3).................  Reporting opacity or    No....................  Subpart RRRRR does not have
                                      VE observations.                                opacity and VE standards
                                                                                      that require the use of
                                                                                      Method 9 of appendix A-4
                                                                                      to 40 CFR part 60 or
                                                                                      Method 22 of appendix A-7
                                                                                      to 40 CFR part 60.
Sec.   63.10(d)(5).................  SSM Reports...........  No. See 63.9641 for     ...........................
                                                              malfunction reporting
                                                              requirements.
Sec.   63.10(e)....................  Additional Reporting    Yes.                    ...........................
                                      Requirements.
Sec.   63.10(f)....................  Waiver of               Yes.                    ...........................
                                      Recordkeeping or
                                      Reporting
                                      Requirements.
Sec.   63.11.......................  Control Device and      No....................  Subpart RRRRR does not
                                      Work Practice                                   require flares.
                                      Requirements.
Sec.   63.12(a)-(c)................  State Authority and     Yes.                    ...........................
                                      Delegations.
Sec.   63.13(a)-(c)................  State/Regional          Yes.                    ...........................
                                      Addresses.
Sec.   63.14(a)-(t)................  Incorporations by       Yes.                    ...........................
                                      Reference.
Sec.   63.15(a)-(b)................  Availability of         Yes.                    ...........................
                                      Information and
                                      Confidentiality.
Sec.   63.16.......................  Performance Track       Yes.                    ...........................
                                      Provisions.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2019-19091 Filed 9-24-19; 8:45 am]
 BILLING CODE 6560-50-P