[Federal Register Volume 86, Number 9 (Thursday, January 14, 2021)]
[Proposed Rules]
[Pages 3054-3079]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-00233]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
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  Federal Register / Vol. 86, No. 9 / Thursday, January 14, 2021 / 
Proposed Rules  

[[Page 3054]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2020-0505; FRL-10017-22-OAR]
RIN 2060-AU66


National Emission Standards for Hazardous Air Pollutants: Carbon 
Black Production Residual Risk and Technology Review and Carbon Black 
Production Area Sources Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing 
amendments to the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) for the Carbon Black Production major source 
category. The proposal addresses the results of the residual risk and 
technology review (RTR) for this source category as required under the 
Clean Air Act (CAA). The proposed amendments address hazardous air 
pollutant (HAP) emissions that occur after the main unit filter of a 
carbon black production unit, as well as emissions from boilers and 
process heaters. The proposed amendments also address the startup, 
shutdown, and malfunction (SSM) provisions of the existing standards, 
and would require electronic reporting of certain notifications, 
performance test results, and semiannual reports. Additionally, the 
proposal addresses the results of the technology review for the Carbon 
Black Production Area Source NESHAP.

DATES: 
    Comments. Comments must be received on or before March 1, 2021. 
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 February 16, 2021.
    Public hearing: If anyone contacts us requesting a public hearing 
on or before January 19, 2021, we will hold a virtual public hearing. 
See SUPPLEMENTARY INFORMATION for information on requesting and 
registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2020-0505, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2020-0505 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2020-0505.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2020-0505, 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. Out of an abundance of caution 
for members of the public and our staff, the EPA Docket Center and 
Reading Room are closed to the public, with limited exceptions, to 
reduce the risk of transmitting COVID-19. Our Docket Center staff will 
continue to provide remote customer service via email, phone, and 
webform. We encourage the public to submit comments via https://www.regulations.gov/ or email, as there may be a delay in processing 
mail and faxes. Hand deliveries and couriers may be received by 
scheduled appointment only. For further information on EPA Docket 
Center services and the current status, please visit us online at 
https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Mr. Korbin Smith Sector Policies and Programs Division 
(D243-04), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-2416; fax number: (919) 541-4991; 
and email address: [email protected]. For specific information 
regarding the risk modeling methodology, contact Mr. James Hirtz, 
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) 
541-0881; fax number: (919) 541-0840; and email address: 
[email protected].

SUPPLEMENTARY INFORMATION:
    Participation in virtual public hearing. Please note that the EPA 
is deviating from its typical approach for public hearings because the 
President has declared a national emergency. Due to the current Centers 
for Disease Control and Prevention (CDC) recommendations, as well as 
state and local orders for social distancing to limit the spread of 
COVID-19, the EPA cannot hold in-person public meetings at this time.
    To request a virtual public hearing, contact the public hearing 
team at (888) 372-8699 or by email at [email protected]. If 
requested, the virtual hearing will be held on January 29, 2021. The 
hearing will convene at 9:00 a.m. Eastern Time (ET) and will conclude 
at 3:00 p.m. ET. The EPA may close a session 15 minutes after the last 
pre-registered speaker has testified if there are no additional 
speakers. The EPA will announce further details at https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen.
    Upon publication of this document in the Federal Register, the EPA 
will begin pre-registering speakers for the hearing, if a hearing is 
requested. To register to speak at the virtual hearing, please use the 
online registration form available at https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen or contact the public hearing

[[Page 3055]]

team at (888) 372-8699 or by email at [email protected]. The 
last day to pre-register to speak at the hearing will be January 26, 
2021. Prior to the hearing, the EPA will post a general agenda that 
will list pre-registered speakers in approximate order at: https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 5 minutes to provide oral testimony. The 
EPA encourages commenters to provide the EPA with a copy of their oral 
testimony electronically (via email) by emailing it to 
[email protected]. The EPA also recommends submitting the text of 
your oral testimony as written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will 
be posted online at https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen. While the EPA expects the hearing to go forward as set forth 
above, please monitor our website or contact the public hearing team at 
(888) 372-8699 or by email at [email protected] to determine if 
there are any updates. The EPA does not intend to publish a document in 
the Federal Register announcing updates.
    If you require the services of a translator or a special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team and describe your needs by January 
21, 2021. The EPA may not be able to arrange accommodations without 
advanced notice.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2020-0505. All documents in the docket are 
listed in https://www.regulations.gov/. Although listed, some 
information is not publicly available, e.g., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy. With the exception of such material, publicly available docket 
materials are available electronically in Regulations.gov.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2020-0505. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov/, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit electronically any information that you consider 
to be CBI or other information whose disclosure is restricted by 
statute. 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.
    The EPA is temporarily suspending its Docket Center and Reading 
Room for public visitors, with limited exceptions, to reduce the risk 
of transmitting COVID-19. Our Docket Center staff will continue to 
provide remote customer service via email, phone, and webform. We 
encourage the public to submit comments via https://www.regulations.gov/ as there may be a delay in processing mail and 
faxes. Hand deliveries or couriers will be received by scheduled 
appointment only. For further information and updates on EPA Docket 
Center services, please visit us online at https://www.epa.gov/dockets.
    The EPA continues to carefully and continuously monitor information 
from the CDC, local area health departments, and our Federal partners 
so that we can respond rapidly as conditions change regarding COVID-19.
    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-2020-0505. Note that 
written comments containing CBI and submitted by mail may be delayed 
and no hand deliveries will be accepted.
    Preamble acronyms and abbreviations. We use multiple acronyms and 
terms in this preamble.

[[Page 3056]]

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
ATSDR Agency for Toxic Substance and Disease Registry
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CCD combustion control device
CDC Centers for Disease Control and Prevention
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
EAV equivalent annual value
EPA Environmental Protection Agency
ERPG emergency response planning guideline
ERT Electronic Reporting Tool
GACT generally available control technology
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
ICBA International Carbon Black Association
ICR Information Collection Request
IRIS Integrated Risk Information System
km kilometer
MACT maximum achievable control technology
mg/m3 milligrams per cubic meter
MIR maximum individual risk
MUF main unit filter
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NATA National Air Toxics Assessment
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NOAEL no observed adverse effect level
NOCS Notification of Compliance Status
NSR New Source Review
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
POM polycyclic organic matter
ppm parts per million
PRA Paperwork Reduction Act
PV present value
RBLC Reasonably Available Control Technology, Best Available Control 
Technology, and Lowest Achievable Emission Rate Clearinghouse
REL reference exposure level
RfC reference concentration
RfD reference dose
RTR residual risk and technology review
SAB Science Advisory Board
SV screening value
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
UF uncertainty factor
[micro]g/m3 microgram per cubic meter
URE unit risk estimate
USGS U.S. Geological Survey

    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 actions are we taking pursuant to CAA sections 112(d)(2) 
and 112(d)(3)?
    B. What are the results of the risk assessment and analyses?
    C. What are our proposed decisions regarding risk acceptability, 
ample margin of safety, and adverse environmental effect?
    D. What are the results and proposed decisions based on our 
technology review?
    E. What other actions are we proposing?
    F. 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 Regulations and Controlling 
Regulatory Costs
    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?

    The source categories that are the subject of this proposal are 
carbon black production major sources regulated under 40 CFR 63, 
subpart YY, and carbon black production area sources, regulated under 
40 CFR 63 Subpart MMMMMM (6M). The North American Industry 
Classification System (NAICS) code for the carbon black production 
industry is 325182. This list of categories and NAICS codes is not 
intended to be exhaustive, but rather provides a guide for readers 
regarding the entities that this proposed action is likely to affect.
    Federal, state, local, and tribal government entities would not be 
affected by this proposed action. The Carbon Black Production major 
source category was added to EPA's source category list June 4,1996 (61 
FR 28197). As defined in the National Emission Standards for Hazardous 
Air Pollutants; Revision of Initial List of Categories of Sources and 
Schedule for Standards Under Sections 112(c) and (e) of the Clean Air 
Act Amendments of 1990, the Carbon Black Production major source 
categories are any facility engaged in the manufacture of carbon black 
using the channel, thermal, or furnace process. (61 FR 28197, June 4, 
1996). The Carbon Black Production area source category was added to 
the EPA's source category list in 2002. (67 FR 70427, November 22, 
2002).

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the internet. Following signature by the 
EPA Administrator, the EPA will post a copy of this proposed action at 
https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen. 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

[[Page 3057]]

https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    The proposed changes to the CFR that would be necessary to 
incorporate the changes proposed in this action are set out in an 
attachment to the memorandum titled Proposed Regulation Edits for 40 
CFR part 63, subpart YY, available in the docket for this action 
(Docket ID No. EPA-HQ-OAR-2020-0505). The document includes the 
specific proposed amendatory language for revising the CFR and, for the 
convenience of interested parties, a redline version of the regulation. 
Following signature by the EPA Administrator, the EPA will also post a 
copy of this memorandum and the attachments to https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen.

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 hazardous air pollutants (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 and revise the 
standards as necessary taking into account any ``developments in 
practices, processes, or control technologies.'' 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.'' 
In certain instances, as provided in CAA section 112(h), the EPA may 
set work practice standards in lieu of numerical emission standards. 
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. 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 pursuant 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 is needed to provide 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 Residual 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 (D.C. Circuit 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). 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

[[Page 3058]]

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). The EPA is required to address regulatory gaps, such as 
missing standards for listed air toxics known to be emitted from the 
source category. Louisiana Environmental Action Network (LEAN) v. EPA, 
955 F.3d 1088 (D.C. Cir. 2020).

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

    The NESHAP for the Carbon Black Production major source category 
was promulgated on July 12, 2002 (67 FR 46258), and codified at 40 CFR 
part 63, subpart YY. Additionally, the Carbon Black Production area 
source NESHAP was promulgated on July 16, 2007 (72 FR 38864), and 
codified at 40 CFR part 63, subpart MMMMMM. Subpart MMMMMM was 
subsequently amended by a direct final rule on March 26, 2008 (73 FR 
15923). As promulgated, the Carbon Black Production major source and 
area source NESHAPs apply to affected sources of HAP at carbon black 
production facilities that are, respectively, major sources and area 
sources of HAP. The affected sources covered by subpart YY include each 
carbon black production process unit, along with associated process 
vents and equipment that are located at a major source, as defined in 
section 112(a) of the CAA.
    Emissions limits in the 2002 major source NESHAP for the Carbon 
Black Production source category were set for process vents associated 
with the main unit filter (MUF). Process vents at the MUF that have a 
HAP concentration of the emission stream equal to or greater than 260 
parts per million by volume (ppmv), must reduce emissions of HAP by the 
use of a flare meeting the requirements of 40 CFR part 63, subpart SS, 
or must reduce emissions of total HAP by 98 weight-percent or to a 
concentration of 20 ppmv, whichever is less stringent, by venting 
emissions through a closed vent system to any combination of control 
devices meeting the requirements of subpart SS of this part, as 
specified in 40 CFR 63.982(a)(2). 40 CFR 63.982(a)(2) specifies 
separate compliance depending on whether the closed vent system is 
routed to a flare, or a non-flare control device. These provisions 
include flare compliance assessments, and specific monitoring, 
recordkeeping, and reporting requirements. Emission limits for the 
Carbon Black Production area source category NESHAP reference the 
provisions of the major source standard.

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

    For the residual risk assessment, the EPA utilized data from the 
2016 National Emissions Inventory (NEI). The NEI is a database that 
contains information about sources that emit criteria air pollutants, 
their precursors, and HAP. The database includes estimates of annual 
air pollutant emissions from point, nonpoint, and mobile sources in the 
50 states, the District of Columbia, Puerto Rico, and the U.S. Virgin 
Islands. The EPA collects this information and releases an updated 
version of the NEI database every 3 years. The NEI contains data 
necessary for conducting the residual risk assessment, including annual 
HAP emissions estimates from individual emission points at facilities 
in the Carbon Black Production source category, and related emissions 
release parameters.
    The 2016 NEI data for the Carbon Black Production source category 
was reviewed and updated as appropriate by the International Carbon 
Black Association (ICBA). Major source members of ICBA represent all 
major sources subject to this regulation. The information received 
included descriptions of HAP-emitting processes, information on the 
HAP-containing materials used, estimates of emissions, and descriptions 
of control technologies, if present.
    The EPA used NEI emissions data and the review by ICBA as the 
primary technical basis for developing the model input files for the 
residual risk assessment for the Carbon Black Production source 
category. Additional information on the development of the modeling 
file for the Carbon Black Production source category can be found in 
the document, Residual Risk Assessment for the Carbon Black Production 
Source Category in Support of the Risk and Technology Review 2020 
Proposed Rule, which is available in the docket for this rulemaking.
    To support both the residual risk assessment and the technology 
review addressed in this action, the EPA visited two carbon black 
production facilities. During the visits, the EPA discussed process 
operations, compliance with the existing NESHAP, description of the 
emission points, process controls, unregulated emissions, and other 
aspects of facility operations. The EPA used the information provided 
by the facilities to understand the various operations, existing 
controls, and new developments in practices, processes, and control 
technologies for the source category. Additional information can be 
found in the site visit reports, the Orion Borger Facility Site Visit 
Report and the Sid Richardson Addis Facility Site Visit Report, which 
are available in the docket for this action.

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

    For the technology review, we reviewed the Reasonably Available 
Control Technology (RACT), Best Available Control Technology (BACT), 
and Lowest Achievable Emission Rate (LAER) Clearinghouse (RBLC). This 
is a database that contains case-specific information on air pollution 
control technologies that have been required to reduce the emissions of 
air pollutants from stationary sources. Under the EPA's New Source 
Review (NSR) program, if a facility is planning new construction or a 
modification that will increase the air emissions above certain defined 
thresholds, an NSR permit may be required. The RBLC promotes the 
sharing of information among permitting agencies and aids in case-by-
case BACT and LAER determinations for NSR permits. We examined 
information contained in the RBLC to determine what technologies are 
currently used for this source category to reduce air emissions and did 
not identify any new technologies.
    Additional information about these data collection activities for 
the technology review is contained in the technology review memorandum, 
Technology Review for the Carbon Black Production Source Category, 
which is available in the docket for this action.

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 
proposal.

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

[[Page 3059]]

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). 
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 emissions of HAP 
that are carcinogens 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 explanation in 
the EPA's response to comments on our policy under the Benzene NESHAP:
---------------------------------------------------------------------------

    \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.

    The 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.''

(54 FR 38057). 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 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\
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    \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.
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    In response to the SAB recommendations, the EPA incorporates 
cumulative risk analyses into its RTR risk assessments. 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 primarily focuses on the identification and

[[Page 3060]]

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. We also review the NESHAP 
and the available data to determine if there are any unregulated 
emissions of HAP within the source category and evaluate this data for 
use in developing new emission standards. 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.B 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 Carbon 
Black Production Source Category in Support of the 2020 Risk and 
Technology Review Proposed Rule. 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 estimated actual emissions and the emission release 
characteristics for each facility in the source category were obtained 
from the 2016 NEI. In addition, the EPA provided draft actual emissions 
data and stack parameters to facilities for review and confirmation. In 
some cases, facilities were contacted to confirm emissions that 
appeared to be outliers, otherwise inconsistent with our understanding 
of the industry, or associated with high risk values in our initial 
risk screening analyses. Where appropriate, emission values and release 
characteristics were corrected, based on revised stack parameter 
information provided by the facilities. Additional information on the 
development of the modeling file for the source category, including the 
development of the actual emissions and emissions release 
characteristics, can be found in the Appendix 1 of the document, 
Residual Risk Assessment for Carbon Black Production Source Category in 
Support of the 2020 Risk and Technology Review Proposed Rule, which is 
available in the docket for this action.
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 19992, 19998 through 19999, April 15, 2005) and in 
the proposed and final Hazardous Organic NESHAP RTR (71 FR 34421, 
34428, June 14, 2006, and 71 FR 76603, 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.)
    In order to calculate allowable emissions, a detailed analysis of 
the source category was conducted to determine how each major source 
facility meets the emissions standards of the Carbon Black NESHAP. With 
respect to the various types of controls used within the source 
category, all facilities use a combination of combustion control 
devices (CCDs). Facilities that manufacture carbon black typically have 
several types of CCDs including but not limited to, flares, 
incinerators, boilers/process heaters, and dryers. CCDs can be used to 
control emissions for a single emissions source, or as is generally the 
case, to control emissions from multiple emission sources/emission 
source types.

[[Page 3061]]

    Historically, the majority of facilities in this source category 
utilize flares to control emissions. Emissions reductions for flares in 
this source category presume to control HAP at a level of 98 percent 
(e.g., see as an example, Technical Supplement 4: Flares in ``2016 
Emissions Inventory Guidelines,'' (TCEQ 2017)). Due to ongoing consent 
decrees, several facilities are transitioning from flares to 
incinerators to reduce criteria pollutants. Since the current emission 
limit allows the use of a flare, or to control emissions to 98 percent, 
and all facilities utilize a CCD meeting those requirements, it is 
appropriate to estimate actual emissions as equal to allowable 
emissions.
    For equipment leaks, which are subject to work practice standards, 
there is no difference between actual and MACT-allowable emissions for 
facilities in the Carbon Black Production source category. This is 
because all facilities are using the same work practice standard, and 
when the work practice standard is correctly applied, the actual 
emissions that result are the same as allowable emissions. For 
additional information on the allowable calculations, see Development 
of the RTR Proposal Risk Modeling Dataset for the Carbon Black 
Production Source Category, available in the docket for this 
rulemaking.
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 proposal 
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) 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 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 classification system is, in general, an adaptation 
of the International Agency for Research on Cancer (IARC, 1982) 
approach for classifying the weight of evidence for human data and 
animal data. The EPA classification system for the characterization 
of the overall weight of evidence for carcinogenicity (animal, 
human, and other supportive data) includes: Group A--Carcinogenic to 
Humans; Group B--Probably Carcinogenic to Humans; Group C--Possibly 
Carcinogenic to Humans; Group D--Not Classifiable as to Human 
Carcinogenicity; and Group E--Evidence of Noncarcinogenicity for 
Humans. These classifications also coincide with the terms, 
``carcinogenic to humans, probably carcinogenic to humans, and 
possibly carcinogenic to humans,'' respectively, which are the terms 
advocated in the EPA's Guidelines for Carcinogenic Risk Assessment, 
published in 1986 (51 FR 33992, September 24, 1986); https://nepis.epa.gov/Exe/ZyPDF.cgi/30004TZX.PDF?/Dockey=/30004TZX.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

[[Page 3062]]

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/glossaries/and/keyword/lists/search.do?/details=/&vocabName=/IRIS%20/Glossary). 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. 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 
revised 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 the Carbon Black Production 
Source Category in Support of the 2020 Risk and Technology Review 
Proposed Rule and in Appendix 5 of the report: Technical Support 
Document for Acute Risk Screening Assessment. This revised approach has 
been used in this proposed rule and in all other 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).
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    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.
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    \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 
Carbon Black Production Source Category in Support of the 2020 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 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,

[[Page 3063]]

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.
---------------------------------------------------------------------------

    \13\ ERPGS Procedures and Responsibilities. March 2014. American 
Industrial Hygiene Association.
---------------------------------------------------------------------------

    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, carbon black is produced at a steady 
state, continuously. Due to the consistency of operation, we do not 
expect significant variability in emissions for this source category. 
To allow for small variations in production, we have assigned an hourly 
acute multiplication factor of two for all emission process groups. A 
further discussion of why this factor was chosen can be found in the 
memorandum, Development of the RTR Proposal Risk Modeling Dataset for 
the Carbon Black Production Source Category, available in the docket 
for this rulemaking.
    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 step is greater than 1, we 
assess the site-specific data to ensure that the acute HQ is at an off-
site location.
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 Carbon Black Production source category, we identified PB-
HAP emissions of arsenic, cadmium, lead, mercury, and polycyclic 
organic matter (POM) of which polycyclic aromatic hydrocarbons is a 
subset, 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 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. We call this application of the TRIM.FaTE model the 
Tier 1 screening assessment. The ratio of a facility's actual emission 
rate to the Tier 1 screening threshold emission rate is a ``screening 
value (SV).''
    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 SV 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 the 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 SV 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

[[Page 3064]]

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.
    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 Residual Risk Assessment for the Carbon Black Production Source 
Category in Support of the Risk and Technology Review 2020 Proposed 
Rule, 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, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), and lead compounds. The acid 
gases included in the screening assessment are hydrochloric acid (HCl) 
and hydrogen fluoride (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 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 Residual Risk 
Assessment for the Carbon Black Production Source Category in Support 
of the Risk and Technology Review 2020 Proposed Rule, which is 
available in the docket for this action.
b. Environmental Risk Screening Methodology
    For the environmental risk screening assessment, the EPA first 
determined whether any facilities in the Carbon Black Production source 
category emitted any of the environmental HAP. For the Carbon Black 
Production source category, we identified emissions of arsenic, 
cadmium, lead, mercury, POM and the two acid gasses, hydrochloric and 
hydrofluoric acid. 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, dioxins/furans, 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 model 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

[[Page 3065]]

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 square kilometers; 
the percentage of the modeled area around each facility that exceeds 
the ecological benchmark for each acid gas; and the area-weighted 
average SV 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 
Residual Risk Assessment for the Carbon Black Production Source 
Category in Support of the Risk and Technology Review 2020 Proposed 
Rule, which is available in the docket for this action.
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 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 2016 NEI. The source category records 
of that NEI dataset were removed, evaluated, and updated as described 
in section II.C of this preamble: What data collection activities were 
conducted to support this action? 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 proposal. 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 Residual Risk 
Assessment for the Carbon Black Production Source Category in Support 
of the Risk and Technology Review 2020 Proposed Rule, available through 
the docket for this action, 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.
    For this source category, we conducted the facility-wide assessment 
using a dataset that the EPA compiled from the 2016 NEI with updated 
emissions and release data provided by industry. We analyzed 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, we made a reasonable attempt to 
identify the source category risks, and these risks were compared to 
the facility-wide risks to determine the portion of facility-wide risks 
that could be attributed to the source category addressed in this 
proposal. 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 Residual Risk Assessment for the Carbon Black Production 
Source Category in Support of the Risk and Technology Review 2020 
Proposed Rule, available through the docket for this action, 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 Residual Risk Assessment for the 
Carbon Black

[[Page 3066]]

Production Source Category in Support of the Risk and Technology Review 
2020 Proposed Rule, 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 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 through 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 
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.
---------------------------------------------------------------------------

    \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

[[Page 3067]]

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.
    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 emissions 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 actual 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\
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    \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.
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    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 RTRs.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the 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, dioxins/furans, lead, mercury (both inorganic and methyl 
mercury), POM, HCl, and HF. These HAP represent pollutants that can 
cause adverse impacts either through direct

[[Page 3068]]

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 actions are we taking pursuant to CAA sections 112(d)(2) and 
112(d)(3)?

    In this proposal, pursuant to CAA section 112(d)(2) and (3), the 
EPA is proposing to broaden the scope of the existing standard, which 
applies to process vents associated with the MUF, to include all 
process vents associated with the carbon black production unit. This 
would require all process vents, including those located after the MUF, 
to control to 98 percent where the HAP concentration of the emission 
stream is equal to or greater than 260 ppmv. Additionally, it would 
require facilities to conduct performance testing on the additional 
process vents located after the MUF.

B. What are the results of the risk assessment and analyses?

    As described above, for the Carbon Black Production major source 
category, we conducted an inhalation risk assessment for all HAP 
emitted, a multipathway screening assessment for the PB-HAP emitted, 
and an environmental risk screening assessment for the PB-HAP and acid 
gasses emitted from the source category. We present results of the risk 
assessment briefly below and in more detail in the Residual Risk 
Assessment for the Carbon Black Production Source Category in Support 
of the Risk and Technology Review 2020 Proposed Rule, which is 
available in the docket for this action.
1. Chronic Inhalation Risk Assessment Results
    The EPA estimated the inhalation risk for the Carbon Black 
Production major source category based on actual and allowable 
emissions. The estimated baseline maximum individual lifetime cancer 
risk (MIR) from inhalation posed by the source category is less than 1-
in-1 million based on actual emissions and MACT-allowable emissions. 
The total estimated cancer incidence based on actual or allowable 
emission levels is 0.00004 excess cancer cases per year, or one case 
every 25,000 years. No one is exposed to cancer risk greater than or 
equal to 1-in-1 million based upon actual and allowable emissions (see 
Table 1 of this preamble).
    The maximum chronic noncancer TOSHI value for the source category 
was estimated to be less than 1 (0.06) based on actual and allowable 
emissions. For both actual and allowable emissions, neurological risks 
were driven by hydrogen cyanide emissions from process filters and 
fugitive emissions.

                               Table 1--Inhalation Risk Assessment Summary for Carbon Black Production \1\ Source Category
                                                              [40 CFR part 63, subpart YY]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Maximum        Estimated
                                          Number of      individual     population at     Estimated
           Risk assessment              facilities 2   cancer risk (1- increased risk   annual cancer       Maximum chronic      Maximum screening acute
                                                        in-1 million)  of cancer >=1-     incidence        noncancer TOSHI 4          noncancer HQ 5
                                                              3         in-1 million   (cases per yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Baseline Actual Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category......................              15            0.06               0         0.00004  <1 (neurological).......  0.09 (REL).
Facility-Wide........................              15            0.06               0         0.00004  <1 (neurological).......
                                      ------------------------------------------------------------------------------------------------------------------
                                                              Baseline Allowable Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category......................              15            0.06               0         0.00004  <1 (neurological).......
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 Based on actual and allowable emissions.
2 Number of facilities evaluated in the risk assessment. Includes 15 operating facilities subject to 40 CFR part 63, subpart YY.
3 Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
4 Maximum TOSHI. The target organ with the highest TOSHI for the Carbon Black Production source category is the neurological system.
5 The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. The acute HQ
  shown was based upon the lowest acute 1-hour dose-response value, the REL for hydrogen cyanide. When an HQ exceeds 1, we also show the HQ using the
  next lowest available acute dose-response value.

2. Screening Level Acute Inhalation Risk Assessment Results
    Based on our screening analysis of reasonable worst-case acute 
exposure to actual emissions from the source category, no HAP exposures 
result in an acute noncancer HQ greater than 0.09 based upon the 1-hour 
REL. As discussed in section III.C.3.c of this preamble, we used an 
acute hourly multiplier of 2 for all emission processes.
3. Multipathway Risk Screening Results
    PB-HAP emissions were reported from 14 of the 15 facilities in the 
source category with seven facilities exceeding the Tier 1 screening 
threshold emission rates for the carcinogenic PB-HAP, arsenic and POM. 
Emissions from two facilities exceeded the Tier 1 screening threshold 
emission rates for mercury and cadmium, which are PB-HAP with noncancer 
health effects. For the PB-HAP and facilities with Tier 1 SVs greater 
than 1, we conducted a Tier 2 screening analysis.
    Two facilities exceeded the arsenic and POM Tier 2 cancer SV with a 
maximum value of 9 for the farmer scenario. One facility exceeded the 
cadmium Tier 2 noncancer SV with a

[[Page 3069]]

maximum value of 2. Two facilities exceeded the mercury Tier 2 
noncancer SV under the fisher scenario, with a maximum value of 4. When 
we evaluated the effect multiple facilities within the source category 
could have on common lake(s) in the modeling domain, mercury and 
cadmium emissions exceeded the noncancer SVs with a maximum value of 4 
and 2, respectively.
    For cadmium and mercury, we continued the fisher scenario screening 
analysis with a Tier 3 multipathway screen which comprises three 
individual stages. These stages included lake, plume rise, and time-
series assessments. A Tier 3 lake assessment was conducted for the two 
facilities with Tier 2 noncancer SVs greater than 1. After conducting 
the lake analysis screen, only one facility was above a noncancer SV of 
1, with a Tier 3 noncancer SV of 2 for mercury, including consideration 
of cumulative lake impacts from facilities within the source category.
    Further details on the Tier 3 screening analysis can be found in 
Appendix 11 of Residual Risk Assessment for the Carbon Black Production 
Source Category in Support of the Risk and Technology Review 2020 
Proposed Rule.''
    An SV in any of the tiers is not an estimate of the cancer risk or 
a noncancer HQ (or HI). Rather, an SV represents a high-end estimate of 
what the risk or HQ may be. For example, facility emissions resulting 
in an SV 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 resulting in a cancer SV of 20 for a carcinogen means that we 
are confident that the cancer risk is lower than 20-in-1 million. Our 
confidence comes from the health-protective assumptions that are 
incorporated into the screens: We choose inputs from the upper end of 
the range of possible values for the influential parameters used in the 
screens and we assume food consumption behaviors that would lead to 
high total exposure. This risk assessment estimates the maximum hazard 
for mercury and cadmium through fish consumption based on upper bound 
screens and the maximum excess cancer risks from POM and arsenic 
through ingestion of fish and farm produce.
    When we progress from the model designs of the Tier 1, 2, and 3 
screens to a site-specific assessment, we refine the risk assessment 
through incorporation of additional site-specific data and enhanced 
model designs. Site-specific refinements include the following: (1) 
Improved spatial locations identifying the boundaries of the watershed 
and lakes within the watershed as it relates to surrounding facilities 
within the source category; (2) calculating actual soil/water run-off 
amounts to target lakes based upon actual soil type(s) and elevation 
changes associated with the affected watershed versus assuming a worst-
case assumption of 100-percent run-off to target lakes; and (3) 
incorporating AERMOD deposition of pollutants into TRIM.FaTE to 
accurately account for site-specific release parameters such as stack 
heights and exit gas temperatures, versus using TRIM.FaTE's simple 
dispersion algorithms that assume the pollutant is uniformly 
distributed within the airshed. These refinements have the net effect 
of improved modeling of the mass of HAP entering a lake by more 
accurately defining the watershed/lake boundaries as well as the 
dispersion of HAP into the atmosphere to better reflect deposition 
contours across all target watersheds and lakes in our 50-km model 
domain.
    As discussed above, the maximum mercury Tier 3 noncancer SV based 
upon the lake analysis resulted in a maximum value of 2. The EPA 
determined that it is not necessary to go beyond the Tier 3 lake 
analysis or conduct a site-specific assessment. As explained above, the 
SV of 2 is a high-end estimate of what the risk or hazard may be and 
can be interpreted to mean that we are confident that the HQ would be 
lower than 2. Further, risk results from five site-specific mercury 
assessments the EPA has conducted for five RTR source categories 
resulted in noncancer HQs that range from 50 times to 800 times lower 
than the respective Tier 2 SV for these facilities (refer to EPA Docket 
ID No. EPA-HQ-OAR-2017-0015 for a copy of these reports).\21\ Based on 
our review of these analyses, we would expect at least a one order of 
magnitude decrease in all Tier 2 noncancer SVs for mercury for the 
Carbon Black Production source category, if we were to perform a site-
specific assessment. In addition, based upon the conservative nature of 
the screens and the level of additional refinements that would go into 
a site-specific multipathway assessment, were one to be conducted, we 
are confident that the HI for ingestion exposure, specifically mercury 
through fish ingestion, is less than 1. Further details on the Tier 3 
screening assessment can be found in Appendix 11 of Residual Risk 
Assessment for the Carbon Black Production Source Category in Support 
of the Risk and Technology Review 2020 Proposed Rule.
---------------------------------------------------------------------------

    \21\ EPA Docket records (EPA-HQ-OAR-2017-0015): Appendix 11 of 
the Residual Risk Assessment for the Taconite Manufacturing Source 
Category in Support of the Risk and Technology Review 2019 Proposed 
Rule; Appendix 11 of the Residual Risk Assessment for the Integrated 
Iron and Steel Source Category in Support of the Risk and Technology 
Review 2019 Proposed Rule; Appendix 11 of the Residual Risk 
Assessment for the Portland Cement Manufacturing Source Category in 
Support of the 2018 Risk and Technology Review Final Rule; and 
Appendix 11 of the Residual Risk Assessment for the Coal and Oil-
Fired EGU Source Category in Support of the 2018 Risk and Technology 
Review Proposed Rule and EPA Docket (EPA-HQ-2019-0373): Appendix 11 
of the Residual Risk Assessment for the Iron and Steel Foundries 
Source Category in Support of the Risk and Technology Review 2019 
Proposed Rule.
---------------------------------------------------------------------------

    In evaluating the potential for adverse health effects from 
emissions of lead, the EPA compared modeled annual lead concentrations 
around each facility to the secondary NAAQS level for lead (0.15 
[micro]g/m\3\, arithmetic mean concentration over a 3-month period. The 
highest annual average lead concentration, of 0.000099 [micro]g/m\3\, 
is below the NAAQS level for lead, indicating a low potential for 
multipathway impacts.
4. Environmental Risk Screening Results
    As described in section III.A of this preamble, we conducted an 
environmental risk screening assessment for the Carbon Black Production 
source category for the following pollutants: arsenic, cadmium, HCL, 
hydrofluoric acid, lead, mercury (methyl mercury and mercuric 
chloride), and POMs.
    In the Tier 1 screening analysis for PB-HAP (other than lead, which 
was evaluated differently), cadmium, methyl mercury, and divalent 
mercury resulted in exceedances of ecological benchmarks for two 
facilities. Cadmium emissions had Tier 1 exceedances for the following 
benchmarks: surface soil no observed adverse effect levels (NOAELs) for 
mammalian insectivores and avian ground insectivores, and fish (avian 
piscivores) NOAEL, geometric-maximum-allowable-toxicant-level, and 
lowest observed adverse effect level benchmarks with a maximum SV of 6. 
Divalent mercury emissions had Tier 1 exceedances for the following 
benchmarks: surface soil threshold level--plant communities, surface 
soil threshold level--invertebrate communities with a maximum SV of 10. 
Methyl mercury emissions had Tier 1 exceedances for the following 
benchmarks: NOAEL--mammalian insectivores and surface soil NOAEL for 
avian ground insectivores with a maximum SV of 10.

[[Page 3070]]

    A Tier 2 screening analysis was performed for cadmium, divalent 
mercury, and methyl mercury emissions. In the Tier 2 screening 
analysis, there were no exceedances of any of the ecological benchmarks 
evaluated for cadmium, divalent mercury, and methyl mercury.
    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.
5. Facility-Wide Risk Results
    As shown in Table 1, the facility-wide risks are the same as the 
risks for actual emissions and allowable emissions from units subject 
to the NESHAP for the Carbon Black Production major source category, 
with no change in incidence or risk drivers.
6. 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 Carbon Black Production 
source category across different demographic groups within the 
populations living near facilities.\22\
---------------------------------------------------------------------------

    \22\ Demographic groups included in the analysis are: White, 
African American, Native American, other races and multiracial, 
Hispanic or Latino, children 17 years of age and under, adults 18 to 
64 years of age, adults 65 years of age and over, adults without a 
high school diploma, people living below the poverty level, people 
living two times the poverty level, and linguistically isolated 
people.
---------------------------------------------------------------------------

    Results of the demographic analysis indicate that, for four of the 
11 demographic groups, African American, age greater than or equal to 
65, age greater than or equal to 25 years of age without a high school 
diploma, and people below the poverty level reside within 5 km of 
facilities in the source category at a percentage greater than the 
corresponding national percentage for the same demographic groups. When 
examining the risk levels of those exposed to emissions from carbon 
black production facilities, we find that no one is exposed to a cancer 
risk at or above 1-in-1 million or to a chronic noncancer TOSHI greater 
than 1.
    The methodology and the results of the demographic analysis are 
presented in a technical report, Risk and Technology Review--Analysis 
of Demographic Factors for Populations Living Near Carbon Black 
Production Source Category Operations, available in the docket for this 
action.

C. What are our proposed decisions regarding risk acceptability, ample 
margin of safety, and adverse environmental effect?

1. Risk Acceptability
    As explained in section II.A of this preamble, the EPA sets 
standards under CAA section 112(f)(2) using ``a two-step standard-
setting approach, with an analytical first step to determine an 
'acceptable risk' that considers all health information, including risk 
estimation uncertainty, and includes a presumptive limit on MIR of 
approximately 1-in-10 thousand'' (54 FR 38045, September 14, 1989). The 
EPA weighed all health risk measures and information, including risk 
estimation uncertainties, in determining whether risk posed by HAP 
emissions from the source category is acceptable.
    The maximum individual lifetime cancer risk (MIR) for inhalation 
exposure to actual and allowable emissions from the Carbon Black 
Production source category (< 1-in-1 million) is two orders of 
magnitude below 100-in-1 million, which is the presumptive upper limit 
of acceptable risk. The EPA estimates emissions from the category would 
result in a cancer incidence of 0.00004 excess cancer cases per year, 
or one case every 25,000 years. Inhalation exposures to HAP associated 
with chronic noncancer health effects result in a TOSHI of 0.06 based 
on actual emissions, 25 times below an exposure that the EPA has 
determined is without appreciable risk of adverse health effects. An 
exposure analysis of HAP with acute noncancer health effects 
demonstrated that the risks are below a level of concern with a max HQ 
equal to 0.09 based upon the 1-hour REL.
    Maximum cancer risk due to ingestion exposures estimated using 
health-protective risk screening assumptions are below 10-in-1 million 
for the Tier 2 farmer exposure scenario. Tier 3 screening analyses of 
mercury exposure due to fish ingestion determined that the maximum HQ 
for mercury would be less than 2 as explained in section III.C.4 of 
this preamble. The EPA is confident that this hazard estimate would be 
reduced to a HQ less than 1, if further refined to incorporate enhanced 
site-specific analyses such as improved model boundary identification 
with improved soil/water run-off calculations and AERMOD deposition 
outputs used in the TRIM.FaTE model. Considering all of the health risk 
information and factors discussed above, as well as the uncertainties 
discussed in section III of this preamble, we propose that the risks 
posed by HAP emissions from the Black Carbon Production source category 
are acceptable.
2. Ample Margin of Safety Analysis
    As directed by CAA section 112(f)(2), we conducted an analysis to 
determine whether the current emissions standards provide an ample 
margin of safety to protect public health. In light of the cancer risk 
being below 1-in-1 million and the noncancer chronic and acute risks 
being below established levels of concern as well as the low potential 
for multipathway risks, we propose to conclude that the existing 
standards provide an ample margin of safety to protect public health.
3. Adverse Environmental Effect
    The emissions data for the Carbon Black Production source category 
indicate that the following environmental HAP are emitted by this 
category: Arsenic, cadmium, HCl, hydrofluoric acid, lead, mercury 
(methyl mercury and mercuric chloride), and POMs. The screening-level 
evaluation of the potential for adverse environmental effects 
associated with emissions of these environmental HAP from the Carbon 
Black Production source category indicated that there are no 
exceedances of Tier 2 screening values for PB-HAP, no exceedances of 
the average modeled concentration around each facility (i.e., the 
average concentration of all off-site data points in the modeling 
domain) for acid gases, and, for lead, we did not estimate any 
exceedances of the secondary lead NAAQS. 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,

[[Page 3071]]

and other relevant factors, an adverse environmental effect.

D. What are the results and proposed decisions based on our technology 
review?

1. Major Source Technology Review
    As described in section III.B of this preamble, the technology 
review focused on the identification and evaluation of developments in 
practices, processes, and control technologies that have occurred since 
the MACT standards were promulgated. In conducting the technology 
review, we reviewed various informational sources regarding the 
emissions from the Carbon Black Production major source category. The 
review included a search of the RBLC database, reviews of air permits 
for carbon black production facilities, and meetings with industry and 
the trade association (summarized in the docket for this action). We 
reviewed these data sources for information on practices, processes, 
and control technologies that were not considered during the 
development of the Carbon Black Production NESHAP. We also looked for 
information on improvements in practices, processes, and control 
technologies that have occurred since the development of the Carbon 
Black Production NESHAP for major sources.
    After reviewing information from the aforementioned sources, we did 
not identify any developments in practices, processes, or control 
technologies used at carbon black production facilities since 
promulgation of the MACT standard.
    Based on the technology review, we are proposing that it is not 
necessary to revise the existing standards because we did not identify 
developments in practices, processes, or control technologies. 
Additional information on our technology review can be found in the 
memorandum, Technology Review for Carbon Black Production Source 
Category, which is available in the docket for this action.
2. Area Source Technology Review
    We performed a technology review of the Carbon Black Production 
area source NESHAP. As part of that review, we determined that there 
are no area sources in this source category currently in operation. 
Given this and the overlap in the requirements for major and area 
sources, we are concluding that it is not necessary to make changes to 
the existing area source standards as a result of this review. For more 
information on the determination that there are no sources subject to 
the area source standard see the memorandum, Identification of Area 
Sources for the Carbon Black Production NESHAP, available in the docket 
for this action.

E. What other actions are we proposing?

    In addition to the proposed actions described above, we are 
proposing four other revisions to the NESHAP. We are proposing 
revisions to the SSM-related provisions of the MACT rule in order to 
ensure that they are consistent with the decision in Sierra Club v. 
EPA, 551 F. 3d 1019 (DC Cir. 2008), in which the court 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 to require electronic reporting 
and annual tune-up requirements for applicable process heaters/boilers. 
Lastly, we are proposing that owners and operators of carbon black 
production process vents subject to the rule conduct performance tests 
every 5 years to demonstrate continued compliance with the NESHAP. A 
discussion of these proposed changes follows.
1. SSM
a. Proposed Elimination of the SSM Exemption
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the D.C. Circuit Court vacated portions of two regulatory 
provisions governing the emissions of HAP during periods of SSM, which 
were promulgated pursuant to CAA section 112. Specifically, the court 
vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 
63.6(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 CAA section 112 
standards apply continuously. Consistent with the court's decision in 
Sierra Club v. EPA, we are proposing standards in this rule that apply 
at all times. We are also proposing several revisions to cross-
references of SSM exemptions in 40 CFR part 63, subpart SS. We also are 
proposing to eliminate and revise certain recordkeeping and reporting 
requirements related to the SSM exemption as further 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.
    We are proposing the elimination of the SSM exemption, which 
currently appears at 40 CFR 63.1108, and any reference to SSM 
requirements in 40 CFR part 63, subpart YY that apply to carbon black 
production affected sources. For example, we are proposing to eliminate 
the incorporation of the requirement that the source develop an SSM 
plan. Additionally, we are proposing to eliminate and revise certain 
recordkeeping and reporting requirements related to the SSM exemption. 
The EPA is also proposing several similar SSM-related revisions to 40 
CFR part 63, subpart YY to remove SSM-related referenced provisions of 
40 CFR part 63, subpart SS (National Emission Standards for Closed Vent 
Systems, Control Devices, Recovery Devices and Routing to a Fuel Gas 
System or a Process). These revisions are discussed in greater detail 
below (see sections IV.E.1.b through j of this preamble).
    In proposing the standards in this rule, the EPA has taken into 
consideration the impacts of the SSM exemption as it relates to startup 
and shutdown periods and is proposing a 13-minute startup work practice 
standard. This added provision is required for safety purposes in the 
absence of the SSM exemption and is discussed further below (see 
section IV.E.1.i of this preamble).
    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) 
(containing regulatory definition of ``malfunction''). The EPA 
interprets CAA section 112 as not requiring emissions that occur during 
periods of malfunction to be factored into development of CAA section 
112 standards. The EPA's interpretation has been upheld as reasonable. 
See United States Sugar Corp. v. EPA, 830 F.3d 579, 606-10 (D.C. Cir. 
2016). Under CAA 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 
CAA section 112 that directs the Agency to consider malfunctions in 
determining the level ``achieved'' by the best performing sources when 
setting emission standards. See, e.g., National

[[Page 3072]]

Ass'n of Clean Water Agencies v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 
2013) (noting that ``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''). 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 D.C. Circuit Court recognized in United States Sugar Corp v. 
EPA, 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. See United States Sugar Corp., 830 F.3d at 608 (discussing work 
practice standards and explaining that ``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 pollutant 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 in 
a way as 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 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 through 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.
    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, 
CAA section 112, is reasonable and encourages practices that will avoid 
malfunctions. 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).
b. Proposed Revisions to 40 CFR Part 63, Subpart YY (and Referenced 40 
CFR Part 63, Subpart SS)
    The EPA assessed existing applicable provisions that apply to 
carbon black production affected sources under 40 CFR part 63, subpart 
YY (including references to 40 CFR part 63, subpart SS), and we are 
proposing to eliminate the applicability of provisions that are no 
longer appropriate, unnecessary, or redundant in the absence of the SSM 
exemption. The revisions to 40 CFR part 63, subpart YY are discussed in 
sections IV.E.1.c through i of this section. The revisions to 40 CFR 
part 63, subpart YY related specifically to references to 40 CFR part 
63, subpart SS are discussed in section IV.E.1.j of this preamble.
c. General Duty
    Section 63.1108(a)(5) states that the emission standards of 40 CFR 
part 63, subpart YY (including the Carbon Black MACT standards) do not 
apply during periods of SSM. However, the paragraph maintains that 
owners and operators still have a general duty to implement measures to 
prevent or minimize excess emissions and that the measures to be taken 
to minimize excess emissions during these times shall be identified in 
the SSM plan (if applicable).
    Similarly, 40 CFR 63.1111(a)(2) states that, during ``periods of 
startup, shutdown, and malfunction, the owner or operator of an 
affected source subject

[[Page 3073]]

to this subpart YY shall operate and maintain such affected source 
(including associated air pollution control equipment and [continuous 
parament monitoring systems] (CPMS)) in a manner consistent with safety 
and good air pollution control practices for minimizing emissions to 
the extent practical. The general duty to minimize emissions during a 
period of startup, shutdown, or malfunction does not require the owner 
or operator to achieve emission levels that would be required by the 
applicable standard at other times if this is not consistent with 
safety and good air pollution control practices, nor does it require 
the owner or operator to make any further efforts to reduce emissions 
if levels required by the applicable standard have been achieved.''
    The current language in 40 CFR 63.1108(a)(5) and 40 CFR 
63.1111(a)(2) characterizes the general duty to minimize emissions 
during periods of SSM. With the elimination of the SSM exemption, there 
is no longer a need to maintain the general duty language of 40 CFR 
63.1108(a)(5) and 63.1111(a)(2) as owners and operators would be 
required to comply with the Carbon Black emission standards at all 
times (including during periods of SSM). Therefore, the EPA is 
proposing to remove the applicability of requirements at 40 CFR 
63.1108(a)(5) (as specified in the proposed 40 CFR 63.1108(a) 
introductory text revisions) and 40 CFR 63.1111(a)(2) (as specified in 
the proposed 40 CFR 63.1111(a) introductory text revisions).
d. SSM Plan
    We are proposing to remove the applicability of requirements at 40 
CFR 63.1111(a) (as specified in the proposed 40 CFR 63.1111(a) 
introductory text revisions) requiring owners and operators to develop 
an SSM plan and specify SSM recordkeeping and reporting requirements 
related to the SSM plan. As noted, the EPA is proposing to remove the 
applicability of the SSM exemptions. Therefore, affected units will be 
subject to emission standards 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.
e. Compliance With Standards
    We are proposing to remove the applicability of the provisions of 
40 CFR 63.1108(a)(1) and (2) (as specified in the proposed 40 CFR 
63.1108(a) introductory text revisions) which exempts sources from 
standards during periods of SSM. As discussed above, the D.C. Circuit 
Court in Sierra Club 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, the EPA is proposing 
to revise standards in this rule to apply at all times.
f. Performance Testing
    The proposal does not include the language that precludes startup 
and shutdown periods from being considered ``representative'' for 
purposes of performance testing, and instead allows performance testing 
during periods of startup or shutdown if specified by the 
Administrator. As in 40 CFR 63.997(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 also proposing to add the 
applicability of the requirements at 40 CFR 63.1108(b)(4)(ii)(B) (as 
specified in the proposed 40 CFR 63.1108(b)(4)(ii)(B) revisions) that 
require the owner and operator maintain records of 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. Finally, the EPA is proposing to add the 
applicability of language clarifying that the owner and operator make 
such records available to the Administrator upon request (as specified 
in the proposed 40 CFR 63.1108(b)(4)(ii)(B) revisions).
g. Recordkeeping
    We are not proposing to change the language at 40 CFR 63.1109(a) 
requiring owners and operators of each affected source to keep copies 
of reports. However, we are proposing to completely remove the 
applicability of the requirements at 40 CFR 63.1111(b) (as specified in 
the proposed 40 CFR 63.1111(b) introductory text revisions), which 
eliminates periodic SSM reports, consequently eliminating the 
requirement to keep a copy of this report. These requirements are no 
longer appropriate for startup and shutdown because SSM plans will no 
longer be required and 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. 
Furthermore, in lieu of the requirements applicable to malfunctions in 
40 CFR 63.1111(b), we are proposing the applicability of the 
recordkeeping requirements at 40 CFR 63.1111(c)(1). The regulatory text 
we are proposing to apply at 40 CFR 63.1111(c)(1)(i) differs from 40 
CFR 63.1111(b) in that 40 CFR 63.1111(b) requires the creation and 
retention of a record for each malfunction during which excess 
emissions occurred, including total duration of all malfunctions for a 
reporting period. 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 total duration of all malfunctions with which excess emissions 
occurred. For each failure to meet an applicable standard, the EPA is 
also proposing to revise the rule to include the applicability of the 
requirements at 40 CFR 63.1111(c)(1)(ii) (as specified in the proposed 
40 CFR 63.1111(c) introductory text revisions). This provision requires 
that sources keep records that include a list of the affected source or 
equipment, 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 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. Furthermore, 
the EPA is proposing to add the applicability of the requirements at 40 
CFR 63.1111(c)(1)(iii) (as specified in the proposed 40 CFR 63.1111(c) 
introductory text revisions) requiring sources keep records of any 
corrective actions taken to return the affected unit to its normal or 
usual manner of operations, and actions taken to minimize emissions in 
accordance with the general duty regulatory text at 40 CFR 
63.1108(a)(4)(ii). 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.
h. Reporting
    We are proposing to remove the applicability of the requirements at 
40 CFR 63.1111(b) (as specified in the proposed 40 CFR 63.1111(b)

[[Page 3074]]

introductory text revisions) which describes the reporting requirements 
for SSM. When applicable, 40 CFR 63.1111(b)(1) requires sources to 
report actions taken during SSM events to show that actions taken were 
consistent with their SSM plan. When applicable, 40 CFR 63.1111(b)(2) 
requires sources to report actions taken during SSM events when actions 
were inconsistent with their SSM plan. The proposed amendments, 
therefore, eliminate the applicability of the requirements at 40 CFR 
63.1111(b)(2) that require reporting of whether the source deviated 
from its SSM plan, including required actions to communicate with the 
Administrator, and the cross-reference to 40 CFR 63.1111(b)(1) 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. We are 
proposing to remove the applicability of the requirements at 40 CFR 
63.1111(b)(2) for reasons discussed above and because 40 CFR 
63.1111(b)(2) describes an immediate report for startups, shutdown, and 
malfunctions 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 SSM were not consistent 
with an SSM plan, because plans would no longer be required.
i. Proposed 13-Minute Startup Control Device Bypass Provision
    In order to address safety concerns related to the elimination of 
applicability of the SSM-related provisions when demonstrating 
compliance with standards under the Carbon Black Production NESHAP, we 
are proposing that the provisions specified in 40 CFR 63.983(a)(1) of 
subpart SS, that each closed vent system shall be designed and operated 
to collect the regulated material vapors from the emission point shall 
apply at all times, unless complying with the 13-minute startup control 
device bypass provision. In accordance with the requirements of CAA 
section 112(h), we are proposing a work practice standard to apply as 
follows: During periods of startup, when the percent excess oxygen of 
the collected vapor is greater than or equal to 3 percent, the closed 
vent system to the control device may be bypassed for the period when 
the excess oxygen concentration is greater than or equal to 3 percent 
or for 13 minutes, whichever time is shorter. At all other times, the 
use of a bypass line on a closed vent system to divert emissions 
subject to the requirements in Table 8 to 40 CFR 63.1103(f) to the 
atmosphere or to a control device not meeting the requirements 
specified in Table 8 of this subpart is an emissions standards 
violation.
    We are proposing this work practice standard because it is not 
feasible to enforce or prescribe an emission standard during startup. 
Due to the combustible nature of the tail gas contained in the ductwork 
and primary bag filter at carbon black facilities, a CCD cannot be 
safely operated until the contents of the ductwork and primary bag 
filter are below 3-percent excess oxygen. If a CCD is used while the 
excess oxygen content is 3 percent or above, this could lead to an 
explosion at the facility.
    After further discussions with the ICBA, we determined that the 13-
minute allotment to bypass the CCD, corresponds with the minimum time 
necessary to completely purge the ductwork and primary bag filter of 
the facility representing the lowest production rate. A lower 
production rate results in a lower flow rate through the ductwork, 
leading to a longer period of time to completely purge the ductwork and 
primary bag filter. Some facilities that operate using a higher 
production rate, will be able to purge the line in less than the 13-
minute allotment. To address this variability, we are proposing to 
require that once facilities are under 3-percent excess oxygen content, 
they must start controlling emissions to meet the applicable emission 
limit. This requirement minimizes emissions from higher production rate 
facilities, that can properly purge the ductwork and primary bag filter 
in less than the 13-minute period.
    In order to further reduce emissions during the 13-minute startup 
work practice period, we are proposing to require that facilities 
operate using the minimum load for standard starting operating 
procedures. This requirement will reduce the amount of new HAP being 
generated during the 13-minute startup period, by limiting the quantity 
of tail gas being produced, thus, reducing the amount of HAP being 
released.
    All facilities in this source category bypass the combustion 
control device until the excess oxygen concentration drops below 3-
percent and use the minimum load for standard starting operating 
procedures during startup, therefore, this practice represents the best 
performers and represents the MACT floor. We did not identify 
additional measures to reduce emissions during this period, and, 
therefore, are proposing a standard based on the MACT floor. Based on 
conversations with industry, there are no other provisions that would 
need to be proposed as a result of the elimination of the SSM-related 
provisions being proposed with this action. For additional information 
on the proposed work practice requirement during periods of startup, 
see the file, SSM Email correspondence with ICBA, available in the 
docket for this action.
j. 40 CFR Part 63, Subpart SS Revisions
    In keeping with the elimination of the SSM exemption, we are also 
proposing in the Carbon Black Production MACT standards at 40 CFR 
63.1103(f)(4) to remove the applicability of SSM-related exemption 
provisions from 40 CFR part 63, subpart SS referenced by the Carbon 
Black Production MACT standards under 40 CFR part 63, subpart YY, 
similar to the revisions to 40 CFR part 63, subpart YY discussed under 
sections IV.1.E.c through h of this preamble. SSM-exemption related 
language being proposed for removal includes specific compliance SSM-
related provisions/language such as ``except during periods of start-
up, shutdown and malfunction specified in a referencing subpart''; 
``other than periods of startups, shutdowns, and malfunctions''; 
language requiring that an SSM plan be prepared and followed; language 
referencing operations during periods of SSM not constituting 
representative conditions for the purpose of a performance test; 
language allowing the exclusion of SSM data when determining compliance 
with a standard; excursion language related to SSM periods; and SSM-
related record requirements.
2. Electronic Reporting
    The EPA is proposing that owners and operators of carbon black 
production facilities submit electronic copies of required performance 
test reports, Notification of Compliance Status (NOCS), and periodic 
reports through the 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 the docket for 
this action.
    The proposed rule requires that performance test results collected 
using test methods that are supported by the

[[Page 3075]]

EPA's Electronic Reporting Tool (ERT) as listed on the ERT website \23\ 
at the time of the test be submitted in the format generated through 
the use of the ERT or an electronic file consistent with the xml schema 
on the ERT website, and other performance test results be submitted in 
portable document format (PDF) using the attachment module of the ERT. 
The proposed rule requires that NOCS reports be submitted as a PDF 
upload in CEDRI.
---------------------------------------------------------------------------

    \23\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For periodic 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 action.\24\ The EPA 
specifically requests comment on the content, layout, and overall 
design of the template.
---------------------------------------------------------------------------

    \24\ See Proposal Form 5900-484 Carbon Black Periodic Report, 
available at Docket ID No. EPA-HQ-OAR-2020-0505.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. These 
circumstances are (1) outages of the EPA's CDX or CEDRI which preclude 
an owner and operator from accessing the system and submitting required 
reports and (2) force majeure events, which are defined as events that 
will be or have been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevent an owner and operator from complying 
with the requirement to submit a report electronically. Examples of 
force majeure events are acts of nature, acts of war or terrorism, or 
equipment failure or safety hazards beyond the control of the facility. 
The EPA is 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. 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.
    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, will further assist in the protection of public health 
and the environment, 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 \25\ to 
implement Executive Order 13563 and is in keeping with the EPA's 
Agency-wide policy \26\ developed in response to the White House's 
Digital Government Strategy.\27\ 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, 
referenced earlier in this section.
---------------------------------------------------------------------------

    \25\ The EPA's Final Plan for Periodic Retrospective Reviews, 
August 2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \26\ 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.
    \27\ 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. Boiler and Process Heater Provisions
    As a result of the EPA's assessment of the MACT standards that 
currently apply to the Carbon Black Production source category under 40 
CFR part 63, subpart YY, the EPA was made aware that there may be 
instances where carbon black production process vents at affected 
sources, route emissions to a boiler/process heater for use as fuel gas 
may not be subject to any requirements. Under the existing standards, 
although emission streams may be subject to the Carbon Black Production 
MACT, these streams are exempt from any requirements under the rule 
when emissions are routed to a boiler/process heater for use as fuel 
gas. The EPA assumed that these boilers/process heaters would be 
subject to the 40 CFR part 63, subpart DDDDD, Industrial, Commercial, 
and Institutional Boilers and Process Heaters NESHAP (Boiler MACT). 
However, under the Boiler MACT, process heaters/boilers covered under 
another standard (as with the Carbon Black Production MACT) would not 
be subject to the Boiler MACT. Specifically, boilers that are used as 
control devices for other NESHAP standards, where at least 50 percent 
of the heat input to the boiler is provided by the NESHAP-regulated gas 
stream would not be subject to the Boiler MACT. This was an unintended 
consequence of the Carbon Black Production MACT rule. We are, 
therefore, proposing that applicable boilers/process heaters that 
receive tail gas for use as fuel gas must comply with annual tune up 
requirements specified in 40 CFR 63.1103(f)(3)(iii). The proposed 
annual boiler/process heater tune-up requirements are similar to what 
is included for gas 1 units under the Boiler MACT.
4. Performance Test Frequency
    The EPA is proposing to revise the MACT standard compliance 
provisions for the Carbon Black Production source category to require 
owners and operators of carbon black production affected source process 
vents subject to the rule conduct performance tests every 5 years. The 
EPA has determined that an initial performance test is insufficient to 
demonstrate continued compliance over time. Thus, this proposed 
revision is necessary to ensure continued compliance with standards.

F. What compliance dates are we proposing?

    Amendments to the Carbon Black Production standards proposed in 
this rulemaking for adoption under CAA section 112(d)(2) and (3) and 
CAA section 112(d)(6) are subject to the compliance deadlines outlined 
in the CAA under CAA section 112(i). New sources, (i.e., sources that 
commence construction or reconstruction after proposal of the standard) 
must comply with the standard immediately upon start-up. Existing 
sources, as described in CAA section 112(i) provides that the 
compliance date shall provide for compliance as expeditiously as 
practicable, but no later than 3 years after the effective date of the 
standard. (``Section 112(i)(3)'s three-year maximum compliance period 
applies generally to any emission standard . . . Association of Battery 
Recyclers v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013).) In determining 
what compliance period is as expeditious as practicable, we consider 
the amount of time needed to plan and construct projects and change 
operating procedures by affected sources. The final action is not 
expected to be a ``major rule'' as defined by 5 U.S.C. 804(2), so the 
effective date of the

[[Page 3076]]

final rule will be the promulgation date as specified in CAA section 
112(d)(10).
    The EPA is proposing several changes that would impact new and 
ongoing compliance requirements for carbon black production affected 
sources under 40 CFR part 63, subpart YY. These changes include: (1) 
Process vent emission standards being expanded to cover all applicable 
(based on an applicability threshold) carbon black production process 
vents; (2) the requirement to conduct performance tests every 5 years 
when demonstrating compliance with process vent emission control 
requirements; (3) boiler and process heater tune up requirements; (4) 
several SSM-related changes (changes proposed as a result of removing 
the applicability of the SSM exemption from the requirements); (5) the 
alternative work practice standard specified in 40 CFR 63.1103(f)(5) 
related to the requirement that a closed vent system route the 
collected vapors to a control device when demonstrating compliance, and 
(6) the addition of requirements to submit reports electronically. The 
compliance applicability dates vary for listed items one through three, 
and four and five.
    The EPA is proposing that, if applicable, all carbon black 
production affected sources that commenced construction or 
reconstruction on or before January 14, 2021, must be in compliance 
with the: (1) Process vent emission standards being expanded to cover 
all applicable (based on an applicability threshold) carbon black 
production process vents; (2) the requirement to conduct performance 
tests every 5 years when demonstrating compliance with process vent 
emission control requirements; and (3) boiler and process heater tune 
up requirements by 1 year after the date the final rule is published in 
the Federal Register. The 1-year allowance for existing sources to 
comply with the rule is based on the EPA's assessment that owners and 
operators will need time to plan, determine applicability of process 
vent requirements, and implement performance testing and control 
requirements (which could include equipment/retrofit investments to 
comply with new requirements). The EPA is also proposing that, if 
applicable, all carbon black production affected sources that commenced 
construction or reconstruction after January 14, 2021, must be in 
compliance with the: (1) Process vent emission standards being expanded 
to cover all applicable (based on an applicability threshold) carbon 
black production process vents; (2) the requirement to conduct 
performance tests every 5 years when demonstrating compliance with 
process vent emission control requirements; and (3) boiler and process 
heater tune up requirements upon initial startup, or the date of 
publication of the final rule in the Federal Register, whichever is 
later.
    For other proposed requirements related to SSM-related changes and 
electronic reporting, the EPA is proposing that all carbon black 
production affected sources that commenced construction or 
reconstruction on or before January 14, 2021, must be in compliance 
with the: (1) SSM-related changes (changes proposed as a result of 
removing the SSM exemption from the requirements); (2) the alternative 
work practice standard specified in 40 CFR 63.1103(f)(5) related to the 
requirement that a closed vent system route the collected vapors to a 
control device when demonstrating compliance; and (3) the addition of 
requirements to submit reports electronically 180 days after 
publication of the final rule in the Federal Register. All carbon black 
production affected sources that commenced construction or 
reconstruction after January 14, 2021, must be in compliance with the: 
(1) SSM-related changes; (2) the alternative work practice standard 
specified in 40 CFR 63.1103(f)(5) related to the requirement that a 
closed vent system route the collected vapors to a control device when 
demonstrating compliance; and (3) the addition of requirements to 
submit reports electronically upon initial startup, or the date of 
publication of the final rule in the Federal Register, whichever is 
later. Based on our assessment, for existing sources, the EPA considers 
a period of 180 days to be the most expeditious compliance period 
practicable for complying with SSM-related and electronic reporting 
requirement change planning and implementation.
    For SSM-related requirement changes, we believe 180 days is 
sufficient for owners and operators of affected sources to familiarize 
themselves with the operational, monitoring, reporting, and 
recordkeeping changes associated with the SSM-related requirement 
changes. Additionally, 180 days is sufficient for owners and operators 
of affected sources to comply with the alternative work practice 
standard that addresses safety concerns as a result of removing the 
applicability of SSM-related provisions when demonstrating compliance 
with standards under the Carbon Black Production NESHAP.\28\
---------------------------------------------------------------------------

    \28\ Section 63.983(a)(1) of 40 CFR part 63, subpart SS requires 
that each closed vent system be designed and operated to collect the 
regulated material vapors from the emission point, and to route the 
collected vapors to a control device, apply at all times.
---------------------------------------------------------------------------

    We are also proposing to change the applicability of requirements 
for SSM by removing the applicability of the exemption from the 
requirements to meet the standard during SSM periods and by removing 
the requirement to develop and implement an SSM plan. Our experience 
with similar industries that are required to convert reporting 
mechanisms to 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, and reliably employ electronic reporting shows that a 
time period of a minimum of 90 days, and, more typically, 180 days is 
generally necessary to successfully accomplish these revisions. Our 
experience with similar industries further shows that owners and 
operators generally require a time period of 180 days to read and 
understand the amended rule requirements; to 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; 
and to update their operation, maintenance, and monitoring plan to 
reflect the revised requirements.
    For electronic reporting changes, the EPA's experience with similar 
industries that are required to convert reporting mechanisms, to 
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, and 
reliably employ electronic reporting shows that a time period of a 
minimum of 90 days, and, more typically, 180 days, is generally 
necessary to successfully accomplish these revisions. 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; to 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; 
and to update their operation, maintenance, and monitoring plan to 
reflect the revised requirements.
    We solicit comment on the proposed compliance periods. 
Specifically, we request that comments in support of, and in opposition 
to, the proposed compliance periods for the differing requirements 
provide supporting

[[Page 3077]]

information as to why or why not the compliance periods proposed are 
sufficient/insufficient.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    The EPA estimates that there are 15 production facilities in the 
Carbon Black Production major source category that will be subject to 
the Carbon Black Production NESHAP affected by the proposed amendments 
to 40 CFR part 63, subpart YY. The basis of our estimates of affected 
facilities is provided in the memorandum, Identification of Major 
Sources for the Carbon Black Production NESHAP, which is available in 
the docket for this action. We are not currently aware of any planned 
or potential new or reconstructed carbon black production facilities in 
the source category.

B. What are the air quality impacts?

    While we are broadening the scope of the current standard, setting 
annual tune up requirements for process heaters/boilers, removing the 
SSM exemption, and establishing a work practice standard for periods of 
startup, we do not have data to determine quantitatively the reduction 
in HAP emissions resulting from this action. Nevertheless, we do not 
anticipate that this action will result in significant HAP emission 
reductions.

C. What are the cost impacts?

    Costs were developed on a per facility basis, and all facilities 
were determined to have similar costs. Costs were valued in 2019 
dollars. Costs were broken into three separate categories based on 
proposed requirements: Initial Applicability Test, Performance Test, 
and Boiler/Process Heater Maintenance Costs.
    Initial applicability testing costs include costs associated with 
the proposed requirement that process vents located after the MUF meet 
the standard, which will require facilities to determine whether 
emissions control is needed for process vents after the MUF process 
vent. We estimate this to be a one-time cost of $21, 350 per facility, 
due to the assumption that the majority of HAP is removed and 
controlled at the MUF, which results in the vent stream concentration 
located after the MUF to fall below the HAP applicability concentration 
threshold (260 ppmv).
    Performance test costs include costs associated with the proposed 
requirement to conduct emissions tests at the subject process vents 
every 5 years starting in the first year of the proposed requirement. 
We estimate that 20 percent of subject facilities will conduct a 
performance test each year resulting in an annual cost of $15,241 per 
facility.
    Boiler/process heater maintenance costs include costs associated 
with the proposed requirement to ensure that boilers and process 
heaters are operating at peak efficiency and not creating excess 
emissions through inefficient operation. Initial tune-up costs are 
assumed to be higher to get the units back to peak efficiency. We 
assume that following year costs would be lower because less 
maintenance would be needed. As such, we estimate the initial tune-up 
cost to be $6,750 per facility and subsequent annual tune-ups to cost 
$1,350 per facility.
    Costs were based primarily on labor, equipment, and travel costs. 
Labor costs are based on Bureau of Labor Statistics data for relevant 
employees necessary to perform the tests and maintenance. A detailed 
cost analysis can be found in the memorandum, Carbon Black Cost 
Memorandum, available in the docket for this action.

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.
    Economic costs to carbon black producers were measured in Present 
Value (PV) total costs and Equivalent Annual Value (EAV) costs. All 
producer facilities were estimated to have similar costs. All costs are 
presented in 2019 dollars. Refer to the memorandum, Carbon Black 
Economic Impact Analysis, in the docket for this rulemaking for more 
information. PV total costs and EAV costs were measured at the 3-
percent and 7-percent discount rate. The duration of analysis was 10 
years which represented two full cycles of cost analysis for the 
proposed requirements. Per facility PV total costs were estimated to be 
$70,000 and $63,000 at the 3-percent and 7-percent discount rates, 
respectively. EAV costs per facility were estimated to be $8,000 and 
$9,000 at the 3-percent and 7-percent discount rates, respectively. The 
combined PV total cost of the proposed requirements for all facilities 
was estimated to be $1,005,000 and $945,000 at the 3-percent and 7-
percent discount rates, respectively. The combined EAV cost of the 
proposed requirements for all facilities was estimated to be $118,000 
and $135,000 at the 3-percent and 7-percent discount rates, 
respectively.
    All carbon black producers subject to this rule were determined to 
be large entities based on Small Business Administration standards. 
Because the PV and EAV costs associated with the proposed revisions are 
minimal, no significant economic impacts from the proposed amendments 
are anticipated. Refer to the Carbon Black Economic Impact Memorandum, 
available in the docket, for more information.

E. What are the benefits?

    Although the EPA does not anticipate any significant reductions in 
HAP emissions as a result of the proposed amendments, we believe that 
the action, if finalized as proposed, would result in improvements to 
the rule, by broadening the current emission limit, requiring an annual 
tune-up for boilers/process heaters, and revising the SSM standards 
such that a standard applies at all times, including periods covered by 
the proposed work practice standard. Additionally, the proposed 
amendments requiring electronic submittal of NOCS reports, performance 
test results, and periodic reports will increase the usefulness of the 
data, are in keeping with current trends of data availability, will 
further assist in the protection of public health and the environment, 
and will ultimately result in reduced reporting burden on the regulated 
community. See section IV.D.3 of this preamble for more information.

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/stationary-sources-
air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-

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black-hydrogen. 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-2020-0505 (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 project website at https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen.

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 the OMB under the PRA. The Information 
Collection Request (ICR) document
    that the EPA prepared has been assigned EPA ICR number 2677.01. You 
can find a copy of the ICR in the docket for this rule, and it is 
briefly summarized here.
    We are proposing changes to the recordkeeping and reporting 
requirements associated with 40 CFR part 63, subpart YY, in the form of 
eliminating the SSM plan and reporting requirements; broadening the 
initial emission limit to include process vents located after the MUF; 
and including the requirement for electronic submittal of reports. In 
addition, the number of facilities subject to the standards changed. 
The number of respondents was reduced from 18 to 15 based on 
consultation with industry representatives and state/local agencies.
    Respondents/affected entities: The respondents to the recordkeeping 
and reporting requirements are owners and operators of carbon black 
production facilities subject to 40 CFR part 63, subpart YY.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart YY).
    Estimated number of respondents: 15 facilities.
    Frequency of response: The frequency of responses varies depending 
on the burden item. Responses include one-time review of rule 
amendments, reports of periodic performance tests, and semiannual 
compliance reports.
    Total estimated burden: The annual recordkeeping and reporting 
burden for responding facilities to comply with all of the requirements 
in the NESHAP, averaged over the 3 years of this ICR, is estimated to 
be 289 hours (per year). The average annual burden to the Agency over 
the 3 years after the amendments are final is estimated to be 213 hours 
(per year) for the Agency. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: The annual recordkeeping and reporting cost 
for responding facilities to comply with all of the requirements in the 
NESHAP, averaged over the 3 years of this ICR, is estimated to be 
$180,928 (rounded, per year). There are no estimated capital and 
operation and maintenance costs. The total average annual Agency cost 
over the first 3 years after the amendments are final is estimated to 
be $10,247.
    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 dockets 
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 [email protected], 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 February 16, 2021. 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, since there 
are no small entities in the source category.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. 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 facilities are known to be engaged in 
the Carbon

[[Page 3079]]

Black Production source category and would not be affected by this 
action. Thus, Executive Order 13175 does not apply to this action.

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's health and risk assessments are contained in 
sections III.A and IV.A and B of this preamble.

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 rulemaking does not involve technical standards.

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).
    The documentation for this decision is contained in sections IV.A, 
IV.B, IV.F, and IV.G of this preamble. As discussed in sections IV.A, 
IV.B, IV.F, and IV.G of this preamble, we performed a demographic 
analysis for each source category, which is an assessment of risks to 
individual demographic groups, of the population close to the 
facilities (within 50 km and within 5 km). In our analysis, we 
evaluated the distribution of HAP-related cancer risks and noncancer 
hazards from the Carbon Black Production source category across 
different social, demographic, and economic groups within the 
populations living near operations identified as having the highest 
risks.
    Results of the demographic analysis performed for the Carbon Black 
Production source category indicate that, for four of the 11 
demographic groups, African American, people age 65 and up, people 
living below the poverty level, and adults over 25 without a high 
school diploma that reside within 5 km of facilities in the source 
category is greater than the corresponding national percentage for the 
same demographic groups. When examining the risk levels of those 
exposed to emissions from carbon black production facilities, we find 
nobody is exposed to a cancer risk at or above 1-in-1 million and 
nobody is exposed to a chronic noncancer TOSHI greater than 1. For 
additional information see the memorandum, Risk and Technology Review--
Analysis of Demographic Factors For Populations Living Near Carbon 
Black Production Source Category Operations, available in the docket 
for this action.

List of Subjects in 40 CFR Part 63

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

Andrew Wheeler,
Administrator.
[FR Doc. 2021-00233 Filed 1-13-21; 8:45 am]
BILLING CODE 6560-50-P