[Federal Register Volume 83, Number 50 (Wednesday, March 14, 2018)]
[Proposed Rules]
[Pages 11314-11341]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-04939]



[[Page 11313]]

Vol. 83

Wednesday,

No. 50

March 14, 2018

Part II





Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Leather 
Finishing Operations Residual Risk and Technology Review; Proposed Rule

  Federal Register / Vol. 83 , No. 50 / Wednesday, March 14, 2018 / 
Proposed Rules  

[[Page 11314]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2003-0194; FRL-9975-21-OAR]
RIN 2060-AT70


National Emission Standards for Hazardous Air Pollutants: Leather 
Finishing Operations Residual Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing 
amendments to the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) for Leather Finishing Operations to address the 
results of the residual risk and technology review (RTR) that the EPA 
is required to conduct in accordance with section 112 of the Clean Air 
Act (CAA). We found risks due to emissions of air toxics to be 
acceptable from this source category and determined that the current 
NESHAP provides an ample margin of safety to protect public health. We 
identified no new cost-effective controls under the technology review 
to achieve further emissions reductions. Therefore, we are proposing no 
revisions to the numerical emission limits based on these analyses. 
However, the EPA is proposing amendments to regulatory provisions 
pertaining to emissions during periods of startup, shutdown, and 
malfunction (SSM); amendments to add electronic reporting; and 
amendments to clarify certain rule requirements and provisions. While 
the proposed amendments would not result in reductions in emissions of 
hazardous air pollutants (HAP), this action, if finalized, would result 
in improved compliance and implementation of the rule.

DATES: Comments. Comments must be received on or before April 30, 2018. 
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 April 13, 2018.
    Public Hearing. If a public hearing is requested by March 19, 2018, 
then we will hold a public hearing on March 29, 2018 at the location 
described in the ADDRESSES section. The last day to pre-register in 
advance to speak at the public hearing will be March 27, 2018.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2003-0194, at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. Regulations.gov is our 
preferred method of receiving comments. However, other submission 
formats are accepted. To ship or send mail via the United States Postal 
Service, use the following address: U.S. Environmental Protection 
Agency, EPA Docket Center, Docket ID No. EPA-HQ-OAR-2003-0194, Mail 
Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460. Use the 
following Docket Center address if you are using express mail, 
commercial delivery, hand delivery, or courier: EPA Docket Center, EPA 
WJC West Building, Room 3334, 1301 Constitution Avenue NW, Washington, 
DC 20004. Delivery verification signatures will be available only 
during regular business hours.
    Do not submit electronically any information you consider to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. See section I.C of this preamble 
for instructions on submitting CBI.
    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://www2.epa.gov/dockets/commenting-epa-dockets.
    Public Hearing. If a public hearing is requested, it will be held 
at EPA Headquarters, EPA WJC East Building, 1201 Constitution Avenue 
NW, Washington, DC 20004. If a public hearing is requested, then we 
will provide details about the public hearing on our Web site at: 
https://www.epa.gov/stationary-sources-air-pollution/leather-finishing-operations-national-emission-standards-hazardous. The EPA does not 
intend to publish another document in the Federal Register announcing 
any updates on the request for a public hearing. Please contact Ms. 
Aimee St. Clair at (919) 541-1063 or by email at [email protected] 
to request a public hearing, to register to speak at the public 
hearing, or to inquire as to whether a public hearing will be held.
    The EPA will make every effort to accommodate all speakers who 
arrive and register. If a hearing is held at a U.S. government 
facility, individuals planning to attend should be prepared to show a 
current, valid state- or federal-approved picture identification to the 
security staff in order to gain access to the meeting room. An expired 
form of identification will not be permitted. Please note that the Real 
ID Act, passed by Congress in 2005, established new requirements for 
entering federal facilities. If your driver's license is issued by a 
noncompliant state, you must present an additional form of 
identification to enter a federal facility. Acceptable alternative 
forms of identification include: Federal employee badge, passports, 
enhanced driver's licenses, and military identification cards. 
Additional information on the Real ID Act is available at https://www.dhs.gov/real-id-frequently-asked-questions. In addition, you will 
need to obtain a property pass for any personal belongings you bring 
with you. Upon leaving the building, you will be required to return 
this property pass to the security desk. No large signs will be allowed 
in the building, cameras may only be used outside of the building, and 
demonstrations will not be allowed on federal property for security 
reasons.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Mr. Bill Schrock, Natural Resources Group, Sector 
Policies and Programs Division (E143-03), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, Research 
Triangle Park, North Carolina 27711; telephone number: (919) 541-5032; 
fax number: (919) 541-0516; and email address: [email protected]. 
For specific information regarding the risk modeling methodology, 
contact Matthew Woody, 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) 541-1535; fax number: (919) 541-0840; and email 
address: [email protected]. For information about the applicability 
of the NESHAP to a particular entity, contact John Cox, Office of 
Enforcement and Compliance Assurance, U.S. Environmental Protection 
Agency, EPA WJC South Building (Mail Code 2227A), 1200 Pennsylvania 
Avenue NW,

[[Page 11315]]

Washington DC 20460; telephone number: (202) 564-1395; and email 
address: [email protected].

SUPPLEMENTARY INFORMATION: 
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2003-0194. All documents in the docket are 
listed in the Regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy. Publicly available docket 
materials are available either electronically in Regulations.gov or in 
hard copy at the EPA Docket Center, Room 3334, EPA WJC West Building, 
1301 Constitution Avenue NW, Washington, DC. The Public Reading Room is 
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. The telephone number for the Public Reading Room is 
(202) 566-1744, and the telephone number for the EPA Docket Center is 
(202) 566-1742.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2003-0194. 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 http://www.regulations.gov, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit information that you consider to be CBI or 
otherwise protected through http://www.regulations.gov or email. This 
type of information should be submitted by mail as discussed in section 
1.C of this preamble. The http://www.regulations.gov Web site is an 
``anonymous access'' system, 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 http://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 disk or CD-ROM 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 http://www.epa.gov/dockets.
    Preamble Acronyms and Abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines the following terms and acronyms here:

AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM-3 model
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guidelines
FR Federal Register
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM-3 Human Exposure Model
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
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
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
QA/QC quality assurance/quality control
RBLC RACT/BACT/LAER Clearinghouse
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
RTO regenerative thermal oxidizer
RTR residual risk and technology review
SAB Science Advisory Board
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
TSD technical support document
UF uncertainty factor
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
VCS voluntary consensus standards

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
    C. What should I consider as I prepare my comments for the EPA?
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
    A. How do we consider risk in our decision-making?
    B. How do we perform the technology review?
    C. How did we estimate post-MACT risks posed by the source 
category?
IV. Analytical Results and Proposed Decisions
    A. What are the results of the risk assessment and analyses?
    B. What are our proposed decisions regarding risk acceptability, 
ample margin of safety, and adverse environmental effects?
    C. What are the results and proposed decisions based on our 
technology review?
    D. What other actions are we proposing?
    E. 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

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I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that this proposed action is likely to 
affect. The proposed standards, once promulgated, will be directly 
applicable to the affected sources. Federal, state, local, and tribal 
government entities would not be affected by this proposed action. On 
July 16, 1992, we published an initial list of source categories to be 
regulated (57 FR 31576), Initial List of Categories of Sources Under 
Section 112(c)(1) of the Clean Air Act Amendments of 1990. The Leather 
Tanning and Finishing Operations source category was not included on 
the initial list, but was added by an update to the list on June 4, 
1996 (61 FR 28207), 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. On October 2, 2000, we proposed a NESHAP 
for the Leather Finishing Operations source category (65 FR 58702). The 
final rule was promulgated on February 27, 2002 (67 FR 9156) 
(henceforth referred to as the ``Leather Finishing NESHAP''), which 
modified the listing of this source category by deleting tanning 
facilities from the definition and renaming the source category 
``Leather Finishing Operations.'' The 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 (see 61 FR 28197, 
28202, June 4, 1996), describes the Leather Finishing Operations source 
category as ``any facility or process engaged in conditioning and 
enhancement processes that give tanned leather distinctive and 
desirable qualities required by end users of the material.''

    Table 1--NESHAP and Industrial Source Categories Affected by This
                             Proposed Action
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               NESHAP and source category                 NAICS code \1\
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Leather Finishing Operations...........................            3161
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\1\ North American Industry Classification System.

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the Internet. Following signature by the 
EPA Administrator, the EPA will post a copy of this proposed action at 
http://www.epa.gov/stationary-sources-air-pollution/leather-finishing-operations-national-emission-standards-hazardous. Following publication 
in the Federal Register, the EPA will post the Federal Register version 
of the proposal and key technical documents at this same Web site. 
Information on the overall RTR program is available at http://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A redline version of the regulatory language that incorporates the 
proposed changes in this action is available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2003-0194).

C. What should I consider as I prepare my comments for the EPA?

    Submitting CBI. Do not submit information containing CBI to the EPA 
through http://www.regulations.gov or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
a disk or CD-ROM that you mail to the EPA, mark the outside of the disk 
or CD-ROM as CBI and then identify electronically within the disk or 
CD-ROM 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 for inclusion in the public docket. If 
you submit a CD-ROM or disk that does not contain CBI, mark the outside 
of the disk or CD-ROM 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 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-2003-
0194.

II. Background

A. What is the statutory authority for this action?

    The statutory authority for this action is provided by sections 112 
and 301 of the CAA, as amended (42 U.S.C. 7401 et seq.). Section 112 of 
the CAA establishes a two-stage regulatory process to develop standards 
for emissions of HAP from stationary sources. Generally, the first 
stage involves establishing technology-based standards and the second 
stage involves evaluating so-called maximum achievable control 
technology (MACT) standards to determine whether additional standards 
are needed to further address any remaining risk associated with HAP 
emissions. This second stage is commonly referred to as the ``residual 
risk review.'' In addition to the residual risk review, the CAA also 
requires the EPA to review standards set under CAA section 112 every 8 
years to determine if there are ``developments in practices, processes, 
or control technologies'' that may be appropriate to incorporate into 
the standards. This review is commonly referred to as the ``technology 
review.'' When the two reviews are combined into a single rulemaking, 
it is commonly referred to as the ``risk and technology review.'' The 
discussion that follows identifies the most relevant statutory sections 
and briefly explains the contours of the methodology used to implement 
these statutory requirements. A more comprehensive discussion appears 
in the document titled CAA Section 112 Risk and Technology Reviews: 
Statutory Authority and Methodology in the docket for this rulemaking.
    In the first stage of the CAA section 112 standard setting process, 
the EPA promulgates technology-based standards under CAA section 112(d) 
for categories of sources identified as emitting one or more of the HAP 
listed in CAA section 112(b). Sources of HAP emissions are either major 
sources or area sources, and CAA section 112 establishes different 
requirements for major source standards and area source standards. 
``Major sources'' are those that emit or have the potential to emit 10 
tons per year (tpy) or more of a single HAP or 25 tpy or more of any 
combination of HAP. All other sources are ``area sources.'' For major 
sources, CAA section 112(d) provides that the technology-based NESHAP 
must reflect the maximum degree of emission reductions of HAP 
achievable (after considering cost, energy requirements, and non-air 
quality health and environmental impacts). These standards are commonly 
referred to as MACT standards. CAA section 112(d)(3) also establishes a 
minimum control level for MACT standards, known as the MACT ``floor.'' 
The EPA must also consider control options that are more stringent than 
the floor. Standards more stringent

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than the floor are commonly referred to as ``beyond-the-floor'' 
standards. In certain instances, as provided in CAA section 112(h), the 
EPA may set work practice standards where it is not feasible to 
prescribe or enforce a numerical emission standard. For area sources, 
CAA section 112(d)(5) gives the EPA discretion to set standards based 
on generally available control technologies or management practices 
(GACT standards) in lieu of MACT standards.
    The second stage in standard-setting focuses on identifying and 
addressing any remaining (i.e., ``residual'') risk according to CAA 
section 112(f). Section 112(f)(2) of the CAA requires the EPA to 
determine for source categories subject to MACT standards 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 process for 
developing standards to address any residual risk and the Agency's 
interpretation of ``ample margin of safety'' developed in the National 
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions 
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene 
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 
Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA 
notified Congress in the Risk Report that the Agency intended to use 
the Benzene NESHAP approach in making CAA section 112(f) residual risk 
determinations (EPA-453/R-99-001, p. ES-11). The EPA subsequently 
adopted this approach in its residual risk determinations and the 
United States Court of Appeals for the District of Columbia Circuit 
(the Court) upheld the EPA's interpretation that CAA section 112(f)(2) 
incorporates the approach established in the Benzene NESHAP. See NRDC 
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach in the CAA process 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] [i.e., 100-in-1 million].'' 54 FR 38045, September 
14, 1989. If risks are unacceptable, the EPA must determine the 
emissions standards necessary to bring risks to an acceptable level 
without considering costs. In the second step of the process, the EPA 
considers whether the emissions standards provide an ample margin of 
safety ``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. After conducting the ample margin of safety analysis, we 
consider whether a more stringent standard is necessary to prevent an 
adverse affect, taking into consideration costs, energy, safety, and 
other relevant factors.
---------------------------------------------------------------------------

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

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

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

    The Leather Finishing NESHAP was promulgated on February 27, 2002 
(67 FR 9156) and codified at 40 CFR part 63, subpart TTTT. The Leather 
Finishing NESHAP defines ``leather finishing'' as ``a single process or 
group of processes used to adjust and improve the physical and 
aesthetic characteristics of the leather surface through the multistage 
application of a coating comprised of dyes, pigments, film-forming 
materials, and performance modifiers dissolved or suspended in liquid 
carriers.'' 40 CFR 63.5460. The Leather Finishing NESHAP does not apply 
to equipment used solely for leather tanning operations or to portions 
of leather finishing operations using a solvent degreasing process 
subject to the Halogenated Solvent Cleaning NESHAP (see 40 CFR 
63.5290(c)).
    There are currently four existing leather finishing operations that 
were identified as subject to the Leather Finishing NESHAP: S.B. Foot 
Tanning Company of Red Wing, MN; Alliance Leather, Inc. of Peabody, MA; 
Pearl Leather Finishers, Inc. of Johnstown, NY; and Tasman Leather 
Group, LLC of Hartland, ME.
    In the overall process of leather products manufacturing, leather 
finishing is considered a dry operation as opposed to the ``wet-end'' 
operations associated with leather tanning. Leather finishing 
operations can be co-located with wet-end tannery operations or 
performed in stand-alone facilities. None of the four existing 
facilities subject to the Leather Finishing NESHAP perform the initial 
wet-end tanning process that produces the commodity product known as 
``wet blues'' or ``blue stock;'' however, based on information 
available in the facility operating permits, the S.B. Foot and Tasman 
facilities each perform retanning, coloring, and fat liquoring 
operations. These are wet-end operations that soften, color, and 
restore fats and oils to the blue stock. The equipment used solely for 
leather tanning operations is not subject to the Leather Finishing 
NESHAP.
    In the dry-end leather finishing operations, coatings are typically 
applied to the leather substrate using spray, roll, and flow coating 
techniques. The emission source types subject to the emission limits 
under the Leather Finishing NESHAP include, but are not limited to 
coating and spraying equipment, coating storage and mixing, and dryers. 
Emissions of HAP occur from volatilization during the application of 
the coating, drying, or curing of the coating, and from handling, 
storage, and clean-up of the finishing materials. Wastewaters laden 
with HAP are also a potential source of emissions at facilities that 
use water curtains and water baths for particulate control. The 
emission point types associated with these emission sources include 
process vents, storage vessels, wastewater, and fugitive sources.
    In developing the Leather Finishing NESHAP, the EPA established 
MACT standards for four types of leather product process operations: 
(1) Upholstery leather with greater than or equal to 4 grams of add-on 
finish per square foot of leather; (2) upholstery leather with less 
than 4 grams of add-on finish per square foot of leather; (3)

[[Page 11318]]

water-resistant leather; and (4) nonwater-resistant leather. The MACT 
standards limit emissions from new and existing leather finishing 
operations and are expressed in terms of total HAP emissions per 1,000 
square feet of leather processed over a rolling 12-month compliance 
period. Sources must record the mass of HAP in coatings applied to the 
leather either through an inventory mass balance or ``measure-as-
applied'' approach. Using the mass balance approach, sources may choose 
to account for disposal of excess finish instead of assuming any excess 
finish is also emitted. Emissions are calculated based on the 
assumption that the entire HAP content of the applied finish is 
released to the environment. Sources using an add-on control device may 
account for the emission reduction achieved from the control device as 
measured by a performance test conducted in accordance with the 
requirements of the Leather Finishing NESHAP.
    Based on the data collected as described in section II.C and D of 
this preamble, HAP emissions from this source category include propyl 
cellosolve, glycol ethers, diethylene glycol monobutyl ether, 
trimethylamine, diethylene glycol monomethyl ether, ethylene glycol, 
toluene, methyl isobutyl ketone, and chromium (III) compounds.

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

    For this RTR, the EPA collected information from the 2014 National 
Emissions Inventory (NEI, version 1), from facility permits and permit 
applications, and through discussions with facility representatives and 
state permitting authorities.
    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 Virgin Islands. The EPA collects this 
information and releases an updated version of the NEI database every 3 
years. The NEI includes information necessary for conducting risk 
modeling, including annual HAP emissions estimates from individual 
emission points at facilities and the related emissions release 
parameters. We used NEI emissions and supporting data as the primary 
source of information to develop the model input file for the risk 
assessment (hereafter referred to as the ``RTR emissions dataset''). 
For more details on the NEI, see https://www.epa.gov/air-emissions-inventories/national-emissions-inventory-nei.
    The EPA also gathered information on annual emissions, emission 
points, air pollution control devices, and process operations from 
facility construction and operating permits. We collected permits and 
supporting documentation from state permitting authorities either 
through direct contact with the agencies or through state-maintained 
online databases. The NEI and facility permits contained much of the 
information we used to develop the RTR emissions dataset. Supplemental 
information was collected via communication with facility 
representatives.
    The EPA contacted facility representatives for three of the four 
leather finishing operations subject to the Leather Finishing NESHAP 
(identified in section II.B of this preamble) to collect supplemental 
and clarifying information for use in the RTR emissions dataset. 
Facility representatives provided information including production 
capacities, coating formulations, HAP emissions, and operating 
schedules. We were unable to establish contact with facility 
representatives for Alliance Leather, Inc. of Peabody, MA; however, the 
Massachusetts Department of Environmental Protection confirmed the 
facility was in operation at the time of our inquiry (November 2016) 
and provided a facility annual emissions report for the 2015 reporting 
year. Contacts with facility representatives, our review of permit 
documentation, and our review of the 2014 NEI are documented in a 
separate memorandum titled Leather Finishing: Residual Risk Modeling 
File Supporting Documentation in the docket for this action.

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

    The EPA's Enforcement Compliance History Online (ECHO) database was 
used as a tool to identify which leather finishing operations were 
potentially subject to the Leather Finishing NESHAP. The ECHO database 
provides integrated compliance and enforcement information for 
approximately 800,000 regulated facilities nationwide. Using the search 
feature in ECHO, the EPA identified 120 facilities that could 
potentially be subject to the Leather Finishing NESHAP. The EPA also 
reviewed the membership directory of the Leather Industries of America 
trade association and supporting documentation for the 2002 rulemaking 
and identified an additional 35 facilities with operations potentially 
subject to the Leather Finishing NESHAP. We then searched state Web 
sites for operating permits for these facilities to determine whether 
the permits stated the facility contained leather finishing operations 
subject to the rule. For facilities for which permits were unavailable, 
we reviewed company Web sites, online news articles, and aerial imagery 
to determine if the facility was still in operation. Of the 155 
identified facilities, we determined that 24 facilities perform leather 
finishing operations and 131 facilities are either closed or do not 
perform leather finishing operations. Of the 24 facilities performing 
leather finishing operations, only four are subject to the Leather 
Finishing NESHAP. The 20 remaining facilities are area sources and not 
subject to the Leather Finishing NESHAP.
    The EPA searched for Reasonably Available Control Technology 
(RACT), Best Available Control Technology (BACT), and Lowest Achievable 
Emission Rate (LAER) determinations in the RACT/BACT/LAER Clearinghouse 
(RBLC). The RBLC is a database that contains case-specific information 
of air pollution 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 by 
a certain amount, an NSR permit must be obtained. This central database 
promotes the sharing of information among permitting agencies and aids 
in case-by-case determinations for NSR permits. We examined information 
contained in the RBLC to determine what technologies are currently used 
at leather finishing operations to reduce air emissions.
    The EPA also reviewed other information sources to determine 
whether there have been developments in practices, processes, or 
control technologies in the leather finishing operations source 
category. We reviewed subsequent regulatory actions for sources similar 
to leather finishing operations and conducted a review of literature 
published by industry organizations, technical journals, and government 
organizations. Additional details regarding our review of these 
information sources is contained in the memorandum titled CAA section 
112(d)(6) Technology Review for the Leather Finishing Source Category 
in the docket for this action.

III. Analytical Procedures

    In this section, we describe the analyses performed to support the

[[Page 11319]]

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

    \2\ The MIR is defined as the cancer risk associated with a 
lifetime of exposure at the highest concentration of HAP where 
people are likely to live. The HQ is the ratio of the potential 
exposure to the HAP to the level at or below which no adverse 
chronic noncancer effects are expected; the HI is the sum of HQs for 
HAP that affect the same target organ or organ system.

``[t]he policy chosen by the Administrator permits consideration of 
multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, 
the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be 
weighed in each individual case. This approach complies with the 
Vinyl Chloride mandate that the Administrator ascertain an 
acceptable level of risk to the public by employing [her] 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 [her] judgment, believes are 
---------------------------------------------------------------------------
appropriate to determining what will `protect the public health'.''

    See 54 FR at 38057, September 14, 1989. Thus, the level of the MIR 
is only one factor to be weighed in determining acceptability of risks. 
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 MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. 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 those HAP risks 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 risks, 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 increased risk of adverse noncancer health effects. In May 
2010, the Science Advisory Board (SAB) advised the EPA ``that RTR 
assessments will be most useful to decision makers and communities if 
results are presented in the broader context of aggregate and 
cumulative risks, including background concentrations and contributions 
from other sources in the area.'' \3\
---------------------------------------------------------------------------

    \3\ The EPA's responses to this and all other key 
recommendations of the SAB's advisory on RTR risk assessment 
methodologies (which is available at: http://yosemite.epa.gov/sab/
sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-
007-unsigned.pdf) are outlined in a memorandum to this rulemaking 
docket from David Guinnup titled, EPA's Actions in Response to the 
Key Recommendations of the SAB Review of RTR Risk Assessment 
Methodologies.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA is incorporating 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this proposal. The Agency is (1) Conducting facility-wide 
assessments, which include source category emission points, as well as 
other emission points within the facilities; (2) combining exposures 
from multiple sources in the same category that could affect the same 
individuals; and (3) for some persistent and bioaccumulative 
pollutants, analyzing the ingestion route of exposure. In addition, the 
RTR risk assessments have always considered aggregate cancer risk from 
all carcinogens and aggregate noncancer HI from all noncarcinogens 
affecting the same target organ system.
    Although we are interested in placing source category and facility-
wide HAP risks in the context of total HAP risks from all sources 
combined in the

[[Page 11320]]

vicinity of each source, we are concerned about the uncertainties of 
doing so. Because of the contribution to total HAP risk from emission 
sources other than those that we have studied in depth during this RTR 
review, such estimates of total HAP risks would have significantly 
greater associated uncertainties than the source category or facility-
wide estimates. Such aggregate or cumulative assessments would compound 
those uncertainties, making the assessments too unreliable.

B. How do we perform the technology review?

    Our technology review focuses on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identify such developments, in order to inform our decision of whether 
it is ``necessary'' to revise the emissions standards, we analyze the 
technical feasibility of applying these developments and the estimated 
costs, energy implications, non-air environmental impacts, and we also 
considered the emission reductions. In addition, we considered the 
appropriateness of applying controls to new sources versus retrofitting 
existing sources.
    Based on our analyses of the available data and information, we 
identify potential developments in practices, processes, and control 
technologies. 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 
(or last updated) the NESHAP, we reviewed a variety of data sources in 
our investigation of potential practices, processes, or controls to 
consider. Among the sources we reviewed were the NESHAP for various 
industries that were promulgated since the MACT standards being 
reviewed in this action. We reviewed the regulatory requirements and/or 
technical analyses associated with these regulatory actions to identify 
any practices, processes, and control technologies considered in these 
efforts that could be applied to emission sources in the Leather 
Finishing Operations source category, as well as the costs, non-air 
impacts, and energy implications associated with the use of these 
technologies. Finally, we reviewed information from other sources, such 
as state and/or local permitting agency databases and industry-
supported databases.

C. How did we estimate post-MACT risks posed by the source category?

    The EPA conducted 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 risks 
within the exposed populations, cancer incidence, and an evaluation of 
the potential for adverse environmental effects. The eight 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 Leather 
Finishing Operations Source Category in Support of the December 2017 
Risk and Technology Review Proposed Rule. The methods used to assess 
risks (as described in the eight primary steps below) are consistent 
with those peer-reviewed by a panel of the EPA's SAB in 2009 and 
described in their peer review report issued in 2010 \4\; they are also 
consistent with the key recommendations contained in that report.
---------------------------------------------------------------------------

    \4\ U.S. EPA SAB. 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, May 2010.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    Data for four leather finishing operations as described in section 
II.C of this preamble were used to create the RTR emissions dataset. 
The emission sources in the RTR emissions dataset include the following 
types of emissions sources currently regulated by the Leather Finishing 
NESHAP: Coating and spraying equipment, coating storage and mixing, and 
dryers. The RTR emissions dataset also includes emissions from buffing 
operations. This RTR emissions dataset is based primarily on emissions 
data from the 2014 NEI, facility permits and permit supporting 
documentation, a state-provided facility annual emissions report, and 
information obtained through contact with facility representatives. 
These data sources provided all of the emissions data in the RTR 
emissions dataset and nearly all of the facility-specific data needed 
to conduct the risk modeling analysis. However, there were a few 
instances where default values were used to fill gaps in the facility-
specific data used in the risk modeling analysis. For example, default 
values were used for fugitive release parameters. Use of defaults is 
discussed in detail in the memorandum titled Leather Finishing: 
Residual Risk Modeling File Supporting Documentation in the docket for 
this action.
    The RTR emissions dataset was refined following an extensive 
quality assurance (QA) check of source locations, emission release 
characteristics, and annual emission estimates. We checked the 
coordinates of each emission source in the dataset using a computer 
program that renders a three-dimensional representation of Earth based 
on satellite imagery to ensure the emission point locations were 
correct. We also confirmed that each stack parameter was within 
acceptable QA range check boundaries. For further information on the 
EPA's QA review, see the memorandum titled Leather Finishing: Residual 
Risk Modeling File Supporting Documentation in the docket for this 
action.
2. How did we estimate MACT-allowable emissions?
    The available emissions data used to develop 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 required to comply with the current MACT 
standards. The emissions level

[[Page 11321]]

allowed to be emitted by the MACT standards is referred to as the 
``MACT-allowable'' emissions level. We discussed the use of both MACT-
allowable and actual emissions in the final Coke Oven Batteries RTR (70 
FR 19998-19999, April 15, 2005) and in the proposed and final Hazardous 
Organic NESHAP RTRs (71 FR 34428, June 14, 2006, and 71 FR 76609, 
December 21, 2006, respectively). In those actions, we noted that 
assessing the risks at the MACT-allowable level is inherently 
reasonable since these risks reflect the maximum level facilities could 
emit and still comply with national emission standards. We also 
explained that it is reasonable to consider actual emissions, where 
such data are available, in both steps of the risk analysis, in 
accordance with the Benzene NESHAP approach. (54 FR 38044, September 
14, 1989).
    We used the RTR emissions dataset discussed in section III.C.1 of 
this preamble to estimate allowable emissions levels. The types and 
sources of data we used to estimate allowable emissions vary by 
facility and leather finishing operation type. Because the Leather 
Finishing NESHAP MACT limits are production-based limits (i.e., pounds 
HAP per square feet of leather processed), estimating MACT-allowable 
emissions for the Leather Finishing Operations source category would be 
accomplished by using the actual production level per leather finishing 
operation type to calculate emissions at the MACT limit per leather 
finishing operation type. However, we do not have actual production 
data (quantity and type of leather) for each permitted leather 
finishing operation because we did not petition facilities for this 
information with an information collection request (ICR). As a result, 
different methods for estimating allowable emissions were warranted for 
each facility and leather finishing operation type. This section 
provides a summary of our method for estimating allowable emissions for 
each facility. Refer to the memorandum titled Leather Finishing: 
Residual Risk Modeling File Supporting Documentation in the docket for 
this action for a more detailed discussion of the data and methods we 
used to calculate allowable emissions for these facilities.
    For Alliance Leather, we estimated allowable emissions for organic 
HAP using the Leather Finishing NESHAP limit on total HAP emissions 
that is specified in the facility's permit, which is 3.7 pounds of HAP 
emitted per 1,000 square feet of leather processed. The facility's 
total allowable annual HAP emission rate was estimated to be the 
product of this HAP limit (3.7 pounds per 1,000 square feet of leather 
processed), the design production capacity of the leather finishing 
process specified in the operating permit (16,200 square feet per 
hour), and the annual operating schedule contained in the 2014 NEI 
(2,000 hours per year). Given that we do not have actual production 
data for this leather finishing operation, we could not calculate the 
MACT-allowable emissions level as described above. However, using 
design production capacity in place of actual production is a more 
conservative approach, yielding a higher estimate for allowable organic 
HAP emissions. As further detailed in the memorandum cited above in 
this section, this approach yielded a total allowable annual HAP 
emission rate of 60 tpy, equivalent to 118 times the actual emission 
rate. Allowable organic HAP emissions for the risk modeling file were 
estimated by multiplying by 118 the actual organic HAP emission rates 
for each emission release point, emission process, and emission unit 
combination.
    For S.B. Foot Tanning Co. and Pearl Leather Finishers, Inc, we also 
do not have actual production data. Further, S.B. Foot has multiple 
leather finishing operations, each subject to a different production-
based NESHAP limit. To calculate the MACT-allowable emissions level for 
each leather finishing operation at the facility, we would need the 
actual production data for each leather finishing operation. Given our 
data limitations for these two facilities, we identified an alternative 
approach for estimating allowable emissions that was not available for 
Alliance Leather. S.B. Foot and Pearl Leather Finishers are subject to 
permitted mass-based limits on volatile organic compound(s) (VOC) 
emissions in tpy. We determined that we could use each facility's 
permitted VOC limit to estimate allowable organic HAP emissions because 
all organic HAP emitted are VOC and, in the coating formulations, there 
is little variation in the ratio of total organic HAP to total VOC. 
Using the ratio of each facility's permitted VOC emission limit to its 
reported \5\ annual VOC emissions, we estimated allowable organic HAP 
emissions as the product of actual organic HAP emissions and this 
ratio. For example, for S.B. Foot, permitted VOC emissions are 200 tpy 
and reported VOC emissions are 88.61 tpy, which yields a ratio of 2.26. 
For Pearl Leather Finishers, permitted VOC emissions are 194,180 pounds 
per year and reported VOC emissions are 41,926 pounds, which yields a 
ratio of 4.63. Using these ratios, we estimated allowable organic HAP 
emissions as the product of actual organic HAP emissions and the ratio. 
For S.B. Foot, actual organic HAP emissions are 16.18 tpy, which 
multiplied by 2.26 yields 36.5 tpy allowable organic HAP emissions. 
Using this same method for Pearl Leather Finishers yields an allowable 
organic HAP emission level of 5.1 tpy. Allowable organic HAP emissions 
for the risk modeling file were estimated for each facility by 
multiplying the actual organic HAP emission rates for each emission 
release point, emission process, and emission unit combination by the 
ratio. Refer to the memorandum cited above in this section for a 
detailed discussion about these data sources and calculations. We 
solicit comment on this proposed method of calculating allowable 
organic HAP emissions for S.B. Foot and Pearl Leather Finishers.
---------------------------------------------------------------------------

    \5\ Reported to the 2014 NEI.
---------------------------------------------------------------------------

    For Tasman Leather Group, LLC., allowable emissions were estimated 
using the maximum HAP emissions allowed for area sources, which is 10 
tpy for all HAP emitted (refer to the memorandum, Leather Finishing: 
Residual Risk Modeling File Supporting Documentation, in the docket for 
this action for further discussion on the status of this facility as an 
area source). Allowable emissions for organic HAP were set equivalent 
to this total annual HAP emission limit of 10 tpy. Allowable organic 
HAP emissions for the risk modeling file were estimated by multiplying 
the actual organic HAP emission rate (as reported in the 2014 NEI) for 
each emission release point, emission process, and emission unit 
combination by a factor of 2.78, which is the ratio of allowable total 
HAP emissions (10 tpy) to actual facility-wide emissions of HAP (3.59 
tpy). Refer to the memorandum cited above in this section for a 
detailed discussion about these data sources and calculations.
    We estimated allowable chromium (III) emissions from buffing 
operations as follows. For S.B. Foot, the allowable rate for each 
chromium-emitting emission release point was set equal to the potential 
to emit value in the facility's permit technical support document 
(TSD), which is 0.319 tpy chromium (III). No additional restrictions on 
chromium (III) emissions were identified. For Pearl Leather Finishers 
and Tasman Leather Group, we used emission factors presented in the 
S.B. Foot permit TSD to estimate the allowable emission rate for each 
chromium emission release point. For Pearl Leather Finishers, based on 
communication with facility representatives regarding average

[[Page 11322]]

production rate, design production capacity, and dust capture, and 
assuming a 90-percent control efficiency, we calculated an allowable 
chromium (III) emission rate of 0.266 tpy. For Tasman Leather Group, 
based on communication with facility representatives, we identified the 
design capacity of each buffing operation and established that four 
buffing operations currently operate. Using this design capacity, we 
calculated allowable chromium emissions based on permit special 
conditions for the facility allowing the operation of 12 such buffing 
units at any given time and requiring a 90-percent particulate removal 
efficiency. Based on these permitted conditions, we calculated an 
allowable chromium (III) emission rate of 4.98 tpy. Refer to the 
memorandum cited above in this section for a detailed discussion about 
these data sources and calculations. We identified no buffing 
operations at Alliance Leather.
    We solicit comment on our proposed methods for estimating allowable 
emissions. In addition to general comments on these proposed methods, 
we are interested in additional data that may improve our estimation of 
allowable emissions.
3. How did we conduct dispersion modeling, determine inhalation 
exposures, and estimate individual and population inhalation risks?
    Both long-term and short-term inhalation exposure concentrations 
and health risks from the source category addressed in this proposal 
were estimated using the Human Exposure Model (HEM-3). 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 risks 
using the exposure estimates and quantitative dose-response 
information.
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 
risks. These dose-response values are the latest values recommended by 
the EPA for HAP. They are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants and are discussed in more detail later in this 
section.
---------------------------------------------------------------------------

    \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 That May Cause Cancer
    In developing the risk assessment for chronic exposures, we use the 
estimated annual average ambient air concentrations of each HAP emitted 
by each source for which we have emissions data in the source category. 
The air concentrations at each nearby census block centroid are used as 
a surrogate for the chronic inhalation exposure concentration for all 
the people who reside in that census block. We calculate the MIR for 
each facility as the cancer risk associated with a continuous lifetime 
(24 hours per day, 7 days per week, 52 weeks per year, for a 70-year 
period) exposure to the maximum concentration at the centroid of 
inhabited census blocks. Individual cancer risks are calculated by 
multiplying the estimated lifetime exposure to the ambient 
concentration of each HAP (in micrograms per cubic meter) by its unit 
risk estimate (URE). The URE is an upper bound estimate of an 
individual's probability 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 the 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.
    To estimate incremental individual lifetime cancer risks associated 
with emissions from the facilities in the source category, the EPA sums 
the risks for each of the carcinogenic HAP \8\ emitted by the modeled 
sources. Cancer incidence and the distribution of individual cancer 
risks for the population within 50 km of the sources are also estimated 
for the source category by summing individual risks. A distance of 50 
km is consistent with both the analysis supporting the 1989 Benzene 
NESHAP (54 FR 38044, September 14, 1989) and the limitations of 
Gaussian dispersion models, including AERMOD.
---------------------------------------------------------------------------

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

c. Risk From Chronic Exposure to HAP That May Cause Health Effects 
Other Than Cancer
    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 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 (https://iaspub.epa.gov/sor_internet/registry/termreg/
searchandretrieve/glossariesandkeywordlists/

[[Page 11323]]

search.do?details=&vocabName=IRIS%20Glossary), 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.'' In cases where an RfC from 
the EPA's IRIS database 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 (http://www.atsdr.cdc.gov/mrls/index.asp); 
(2) the CalEPA Chronic Reference Exposure Level (REL) (http://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.
d. 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. We use the peak hourly emission rate,\9\ worst-case 
dispersion conditions, and, in accordance with our mandate under 
section 112 of the CAA, the point of highest off-site exposure to 
assess the potential risk to the maximally exposed individual.
---------------------------------------------------------------------------

    \9\ In the absence of hourly emission data, we develop estimates 
of peak hourly emission rates by multiplying the average actual 
annual emissions rates by a default factor (usually 10) to account 
for variability. This is documented in Residual Risk Assessment for 
the Leather Finishing Operations Source Category in Support of the 
December 2017 Risk and Technology Review Proposed Rule and in 
Appendix 5 of the report: Analysis of Data on Short-term Emission 
Rates Relative to Long-term Emission Rates. 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 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.'' \10\ 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.\11\ 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/m3 
(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.'' 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.
---------------------------------------------------------------------------

    \10\ 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 http://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
    \11\ National Academy of Sciences (NAS), 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).
---------------------------------------------------------------------------

    ERPGs are developed for emergency planning and are intended as 
health-based guideline concentrations for single exposures to 
chemicals.'' \12\ Id. at 1. The ERPG-1 is defined as ``the maximum 
airborne concentration below which it is believed that nearly all 
individuals could be exposed for up to 1 hour without experiencing 
other than mild transient adverse health effects or without perceiving 
a clearly defined, objectionable odor.'' Id. at 2. Similarly, the ERPG-
2 is defined as ``the maximum airborne concentration below which it is 
believed that nearly all individuals could be exposed for up to one 
hour without experiencing or developing irreversible or other serious 
health effects or symptoms which could impair an individual's ability 
to take protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \12\ ERPGS Procedures and Responsibilities. March 2014. American 
Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf.
---------------------------------------------------------------------------

    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, facility-specific actual emissions were 
used to calculate peak hourly emissions in our acute inhalation 
screening risk assessment. For each HAP emitted by a facility, the peak 
hourly emission rate was calculated by dividing the actual annual 
emission rate by facility-specific annual operating hours and 
multiplying this hourly rate by an acute emission multiplier of 1.8. 
The multiplier was developed using U.S. census data reported in 2012 
through 2017 for leather finishing operations production capacity 
utilization over the period 2011 through 2016. The multiplier was 
calculated as the ratio of the highest

[[Page 11324]]

production rate capacity use factor (87.5) to the lowest production 
rate capacity use factor (46.6). Emissions from leather finishing 
operations are primarily from coatings operations. The production 
capacity of leather finishing operations is constrained by the amount 
of time it takes to apply and cure coatings, and machines are running 
more or less continuously, which gives a smooth temporal profile and, 
thus, a low emission adjustment factor. Consequently, actual emissions 
and acute hourly emissions will be similar, and the selected adjustment 
factor of 1.8 was selected over the default adjustment factor of 10. 
The description of how peak hourly emissions were calculated and 
additional information regarding operating hours at each facility in 
the source category can be found in Appendix 1--Emissions Inventory 
Support Document of the document titled Residual Risk Assessment for 
the Leather Finishing Operations Source Category in Support of the 
December 2017 Risk and Technology Review Proposed Rule in the docket 
for this rulemaking.
    In our acute inhalation screening risk assessment, acute impacts 
are deemed negligible for HAP where acute HQs are less than or equal to 
1 (even under the conservative assumptions of the screening 
assessment), and no further analysis is performed for these HAP. In 
cases where an acute HQ from the screening step is greater than 1, we 
consider additional site-specific data to develop a more refined 
estimate of the potential for acute impacts of concern. For this source 
category, the data refinements employed consisted of ensuring the 
locations where the maximum HQ occurred were off facility property and 
where the public could potentially be exposed. Also in estimating acute 
risks for the Leather Finishing Operations source category, we employed 
the following data refinements in calculating peak hourly emissions, as 
described above in this section: Used facility-specific operating hour 
data and developed an industry-specific multiplier based on industry-
specific U.S. census data. These refinements are discussed more fully 
in the Residual Risk Assessment for the Leather Finishing Operations 
Source Category in Support of the December 2017 Risk and Technology 
Review Proposed Rule, which is available in the docket for this action.
4. How did we conduct the multipathway exposure and risk screening 
assessment?
    The EPA conducted 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 determined 
whether any sources in the source category emitted any HAP known to be 
persistent and bioaccumulative in the environment (PB-HAP), as 
identified in the EPA's Air Toxics Risk Assessment Library (See Volume 
1, Appendix D, at http://www2.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the Leather Finishing Operations source category, we did not 
identify emissions of any PB-HAP. Because we did not identify PB-HAP 
emissions, no further evaluation of multipathway risk was conducted for 
this source category.
5. How did we assess risks considering emissions control options?
    While emission control technologies were considered, the analysis 
determined the available control technologies were not cost effective 
for reducing HAP emissions from leather finishing operations. 
Therefore, we did not assess risk on the emission control options. For 
more information regarding analysis of available control technologies, 
see the memorandum, CAA section 112(d)(6) Technology Review for the 
Leather Finishing Source Category, which is available in the docket for 
this action.
6. How did we conduct the environmental risk screening assessment?
a. Adverse Environmental Effects, Environmental HAP, and Ecological 
Benchmarks
    The EPA conducts a screening assessment to examine the potential 
for adverse environmental effects 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, polycyclic organic 
matter, 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, were 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 the Leather Finishing Operations source category, we did not 
identify emissions of any PB-HAP. Because we did not identify PB-HAP 
emissions, no further evaluation of ecological impacts was conducted 
for this source category.
    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 Leather Finishing Operations Source Category in Support 
of the Risk and Technology Review December 2017 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 Leather

[[Page 11325]]

Finishing Operations source category emitted any of the environmental 
HAP. For this source category, we did not identify emissions of any of 
the eight environmental HAP included in the screen. Because we did not 
identify environmental HAP emissions, no further evaluation of 
environmental risk was conducted.
7. How did 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 that the EPA compiled from the 2014 NEI. We used the 
NEI data for the facility and did not adjust any category or ``non-
category'' data. Therefore, there could be differences in the dataset 
from that used for the source category assessments described in this 
preamble. 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 Leather 
Finishing Operations Source Category in Support of the Risk and 
Technology Review December 2017 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.
8. How did 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 
Leather Finishing Operations Source Category in Support of the Risk and 
Technology Review December 2017 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 QA/
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 risks 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

[[Page 11326]]

stated in the EPA's 2005 Cancer Guidelines; 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'' (EPA's 2005 Cancer Guidelines, pages 1-7). This 
is the approach followed here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been 
developed to generally provide an upper bound estimate of risk. 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).\13\ In some circumstances, the true risk could be as low as 
zero; however, in other circumstances the risk could be greater.\14\ 
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 (U.S. EPA, 1993 and 1994) 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.
---------------------------------------------------------------------------

    \13\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \14\ 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.
---------------------------------------------------------------------------

    Many of the UFs used to account for variability and uncertainty in 
the development of acute dose-response values are quite similar to 
those developed for chronic durations. Additional adjustments are often 
applied to account for uncertainty in extrapolation from observations 
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all 
acute dose-response values are developed for the same purpose, and care 
must be taken when interpreting the results of an acute assessment of 
human health effects relative to the dose-response value or values 
being exceeded. Where relevant to the estimated exposures, the lack of 
acute dose-response values at different levels of severity should be 
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks 
for the environmental risk screening assessment. We established a 
hierarchy of preferred benchmark sources to allow selection of 
benchmarks for each environmental HAP at each ecological assessment 
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but 
not all combinations of ecological assessment/environmental HAP had 
benchmarks for all three effect levels. Where multiple effect levels 
were available for a particular HAP and assessment endpoint, we used 
all of the available effect levels to help us determine whether risk 
exists and whether the risk could be considered significant and 
widespread.
    Although every effort is made to identify appropriate human health 
effect dose-response values for all pollutants emitted by the sources 
in this risk assessment, some HAP emitted by this source category are 
lacking dose-response assessments. Accordingly, these pollutants cannot 
be included in the quantitative risk assessment, which could result in 
quantitative estimates understating HAP risk. To help to alleviate this 
potential underestimate, where we conclude similarity with a HAP for 
which a dose-response value is available, we use that value as a 
surrogate for the assessment of the HAP for which no value is 
available. To the extent use of surrogates indicates appreciable risk, 
we may identify a need to increase priority for an IRIS assessment for 
that substance. We additionally note that, generally speaking, HAP of 
greatest concern due to environmental exposures and hazard are those 
for which dose-response assessments have been performed, reducing the 
likelihood of understating risk. Further, HAP not included in the 
quantitative assessment are assessed qualitatively and considered in 
the risk characterization that informs the risk management decisions, 
including consideration of HAP reductions achieved by various control 
options.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective dose-response value 
of an individual compound in that group to estimate risk. Similarly, 
for an individual compound in a group (e.g., ethylene glycol diethyl 
ether) that does not have a specified dose-response value, we also 
apply the most protective dose-response value from the other compounds 
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA. The 
accuracy of an acute inhalation exposure assessment depends on the 
simultaneous occurrence of independent factors that may vary greatly, 
such as hourly emissions rates, meteorology, and the presence of humans 
at the location of the maximum concentration. In the acute screening 
assessment that we conduct under the RTR program, we assume that peak 
emissions from the source category and worst-case meteorological 
conditions co-occur, thus, resulting in maximum ambient concentrations. 
These two events are unlikely to occur at the same time, making these 
assumptions conservative. We then include the additional assumption 
that a person is located at this point during this same time period. 
For this source category, these assumptions would tend to be worst-case 
actual exposures as it is unlikely that a person would be located at 
the point of maximum exposure during the time when peak emissions and 
worst-case meteorological conditions occur simultaneously.

IV. Analytical Results and Proposed Decisions

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

    We present results of the Leather Finishing Operations source 
category risk assessment briefly below and in more detail in the 
residual risk document, Residual Risk Assessment for the Leather 
Finishing Operations Source Category in Support of the December 2017 
Risk and Technology Review Proposed Rule, in the docket for this 
action.
1. Inhalation Risk Assessment Results
    Table 2 of this preamble provides a summary of the results of the 
inhalation risk assessment for the source category.

[[Page 11327]]



                                        Table 2--Leather Finishing Operations Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                        Maximum  individual      Estimated population  at    Estimated  annual cancer     Maximum  chronic  non-      Maximum screening
                        cancer risk  (in 1       increased  risk of cancer     incidence  (cases per         cancer  TOSHI \3\       acute non-cancer HQ
                           million) \2\              >= 1-in-1 million                 year)           ----------------------------          \4\
     Number of     ------------------------------------------------------------------------------------                            ---------------------
  facilities \1\      Based on      Based on      Based on      Based on      Based on      Based on      Based on      Based on
                       actual       allowable      actual       allowable      actual        actual        actual       allowable      Based on actual
                      emissions     emissions     emissions     emissions     emissions     emissions     emissions     emissions      emissions level
                      level \2\       level       level \2\       level         level         level         level         level
--------------------------------------------------------------------------------------------------------------------------------------------------------
4.................            0             0             0             0             0             0          0.04           0.3   HQREL = 3 (propyl
                                                                                                                                     cellosolve and
                                                                                                                                     glycol ethers)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Maximum TOSHI. The target organ with the highest TOSHI for the Leather Finishing Operations source category is the reproductive target organ.
\4\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values
  shown use the lowest available acute threshold value, which in most cases is the REL. When an HQ exceeds 1, we also show the HQ using the next lowest
  available acute dose-response value.

    The results of the inhalation risk modeling using actual emissions 
data, as shown in Table 2 of this preamble, indicate the maximum 
chronic noncancer TOSHI value could be up to 0.04. While we would have 
estimated incremental individual lifetime cancer risks as discussed in 
section III.C.3.b of this preamble, there were no carcinogenic HAP 
emissions from this source category, so the maximum lifetime individual 
cancer risk is 0 and the total estimated national cancer incidence from 
these facilities based on actual emission levels is no excess cancer 
cases per year.
2. Acute Risk Results
    Table 2 of this preamble indicates that for the Leather Finishing 
Operations source category, the maximum HQ is 3, driven by propyl 
cellosolve and glycol ethers. The only acute dose-response value for 
propyl cellosolve and glycol ethers is the REL; therefore, only the 
HQREL is provided. Refinement of the acute risk results was 
performed using aerial photos to ensure that the location where the 
maximum risk was projected to occur was, in fact, a location where the 
general public could be exposed. The result of this refinement 
confirmed that the maximum acute risk result occurred where the public 
could potentially be exposed. This refinement, therefore, had no impact 
on the maximum HQ. For more detailed acute risk results refer to the 
draft residual risk document, Residual Risk Assessment for the Leather 
Finishing Operations Source Category in Support of the December 2017 
Risk and Technology Review Proposed Rule, in the docket for this 
action.
3. Multipathway Risk Screening Results
    There are no PB-HAP emitted by facilities in this source category. 
Therefore, we do not expect any human health multipathway risks as a 
result of HAP emissions from this source category.
4. Environmental Risk Screening Results
    There are no ``environmental HAP'' emitted by facilities in this 
source category. Therefore, we do not expect an adverse environmental 
effect as a result of HAP emissions from this source category.
5. Facility-Wide Risk Results
    An assessment of risk from facility-wide emissions was performed to 
provide context for the source category risks. Using the NEI data 
described in sections II.C and III.C of this preamble, the maximum 
cancer risk in the facility-wide assessment was 0.09-in-1 million and 
the maximum chronic noncancer HI index was 0.1 (for the reproductive 
system), both driven by emissions from external combustion boilers.
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 Leather Finishing 
Operations source category across different demographic groups within 
the populations living near facilities.\15\
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    \15\ 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.
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    Results of the demographic analysis indicate that, for 1 of the 11 
demographic groups, Ages 65 and up, the percentage of the population 
living 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 
leather finishing operations, 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 Leather Finishing 
Operations, available in the docket for this action.

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

1. Risk Acceptability
    We weigh all health risk factors in our risk acceptability 
determination, including the cancer MIR, the number of persons in 
various cancer and non-cancer risk ranges, cancer incidence, the 
maximum non-cancer TOSHI, the maximum acute non-cancer HQ, the extent 
of non-cancer risks, the distribution of cancer and non-cancer risks in 
the exposed population, and risk estimation uncertainties (54 FR 38044, 
September 14, 1989).
    For the Leather Finishing Operations source category, the risk 
analysis indicates that the cancer risks to the individual most exposed 
are below 1-in-1 million from both actual and allowable emissions. 
These risks are considerably less than 100-in-1 million, which is the 
presumptive upper limit of acceptable risk. The risk analysis also 
shows no cancer incidence, as well as maximum chronic noncancer TOSHI 
value of 0.04, which is significantly below 1. In addition, the risk 
assessment indicates no significant potential for multi-pathway health 
effects. The acute

[[Page 11328]]

non-cancer risks indicate a maximum HQ of 3.
    Considering all the health risk information and factors discussed 
above, including the uncertainties, we propose to find that the risks 
from the Leather Finishing Operations source category are acceptable.
2. Ample Margin of Safety Analysis
    Although we are proposing that the risks from the Leather Finishing 
Operations source category are acceptable, risk estimates indicate the 
maximum acute non-cancer HQ screening estimate was greater than 1, 
driven by emissions of propyl cellosolve and glycol ethers and based on 
allowable emissions, as further discussed in section IV.A.2 of this 
preamble. We considered options for further reducing gaseous organic 
HAP emissions from leather finishing operations. The greatest reduction 
in organic HAP emissions that could be achieved for these operations 
would result from use of a concentrator followed by a regenerative 
thermal oxidizer (RTO), which we estimate would remove 98 percent of 
organic HAP emissions. Biological treatment together with use of a 
concentrator would achieve 84-percent removal of organic HAP emissions. 
Section IV.C of this preamble discusses the costs and impacts 
associated with use of these control technologies. The resulting cost-
effectiveness values for operating the concentrator followed by a RTO 
and for operating the concentrator plus biological treatment are 
$54,000 and $62,000 per ton of HAP removed, respectively. Due to our 
determinations that cancer risks are below 1-in-1 million and that the 
maximum chronic noncancer TOSHI value is below 1, uncertainties 
associated with the acute screening risk estimate (refer to the risk 
report titled Residual Risk Assessment for the Leather Finishing 
Operations Source Category in Support of the December 2017 Risk and 
Technology Review Proposed Rule in the docket for this action), and the 
substantial costs associated with the control options, we are proposing 
that additional standards for this source category are not required to 
provide an ample margin of safety to protect public health, and that 
the current standards provide an ample margin of safety to protect 
public health.
3. Adverse Environmental Effects
    We did not identify emissions of any of the eight environmental HAP 
included in our environmental risk screening, and 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 promulgate a 
more stringent standard to prevent an adverse environmental effect, 
taking into consideration costs, energy, safety, and other relevant 
factors.
    For the reasons above, we are not proposing to make any amendments 
to the existing NESHAP pursuant to CAA section 112(f)(2).

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

    As described in section III.B of this preamble, our technology 
review focused on identifying developments in the practices, processes, 
and control technologies for the Leather Finishing Operations source 
category. The EPA reviewed various information sources regarding 
emissions sources that are currently regulated by the Leather Finishing 
NESHAP, which include, but are not limited to, coating and spraying 
equipment, coating storage and mixing, and dryers.
    As discussed further in sections II.C and D of this preamble, we 
conducted a search of the RBLC, other regulatory actions (MACT 
standards, area source standards, and residual risk standards) since 
the 2002 Leather Finishing NESHAP, literature related to research 
conducted for emission reductions from leather finishing operations 
emission sources, and state permits.
    We reviewed these data sources for information on add-on control 
technologies, other treatment units, work practices, procedures, and 
process alternatives that were not considered during the development of 
the Leather Finishing NESHAP. We also looked for information on 
improvements in add-on control technology, other treatment units, work 
practices, procedures, and process changes or pollution prevention 
alternatives that have occurred since development of the Leather 
Finishing NESHAP.
    After reviewing information from the aforementioned sources, we 
identified two control technologies for further evaluation that are 
technically feasible for use at leather finishing operations, but were 
not investigated during the original rule development: biological 
treatment and concentrators. Biological treatment was identified as a 
result of our literature review. In biological treatment, organic 
pollutants are converted to water and carbon dioxide after being 
consumed as food by microbes. Biological treatment can include 
biofilters, bio-trickling filters, and bioscrubbers among others. The 
use of a concentrator was identified by our review of residual risk 
standards. The technology review conducted for the Ship Building and 
Ship Repair source category identified the use of a concentrator, 
combined with an RTO, to control emissions from spray booths (75 FR 
80239). A concentrator uses an adsorbent to remove organic pollutants 
from an exhaust stream. Those pollutants are then desorbed from the 
adsorbent material using a stream much smaller in volume than the 
original exhaust stream. This lower flow rate stream is then directed 
to an RTO to destroy the desorbed pollutants. By using a concentrator, 
the resulting low flow rate, higher pollutant concentration stream is 
more economical to treat in an RTO than a high volume low concentration 
stream. The economics of operating a biological treatment unit could 
also potentially be improved in a similar manner by use of a 
concentrator.
    We evaluated the annual cost and emissions reductions of using 
biological treatment to reduce HAP emissions at each of the four 
leather finishing operations subject to the Leather Finishing NESHAP. 
Annual costs for each facility ranged from $43,000 to $417,000 per year 
for a total of approximately $840,000 for the industry. Assuming a 
control efficiency of 85 percent, HAP emissions would be reduced by 
approximately 0.43 tpy for the facility with the smallest projected 
reduction to 14 tpy for the facility with the largest projected 
reduction, for a cumulative total of 18 tpy for the four facilities 
subject to the Leather Finishing NESHAP. To install biological 
treatment at each facility, the resulting cost effectiveness ranged 
from $30,000 to $110,000 per ton of HAP reduced. Considering the high 
costs per ton of HAP reduced associated with the installation of 
biological treatment, we did not consider this technology to be cost 
effective for further reducing HAP emissions from leather finishing 
operations.
    During proposal of the Leather Finishing NESHAP, we considered the 
use of an RTO to control HAP emissions from leather finishing 
operations as a ``beyond-the-floor'' option; however, we rejected it 
because of a significantly higher cost per ton of emissions reductions 
(65 FR 58706). Our technology review revealed the use of a concentrator 
in addition to an RTO as a potential improvement in add-on control 
technology. We evaluated the annual cost and emissions reductions of 
using a rotary concentrator combined with an RTO and, as an 
alternative, a rotary concentrator combined with a

[[Page 11329]]

biological treatment unit for a model facility. Our analysis evaluated 
the annual costs of only the rotary concentrator on the basis that if 
operation of the concentrator is not cost effective, then operating 
both the concentrator and an RTO or biological treatment unit is also 
not cost effective. We calculated a total annual cost of operating the 
rotary concentrator of approximately $284,000 per year. Applying a 
control efficiency of 98 percent for the rotary concentrator and RTO, 
we calculated annual HAP emission reductions of 5.2 tpy. Assuming a 
control efficiency of 84 percent for the rotary concentrator and 
biological treatment combination, we calculated an annual HAP emission 
reduction of 4.5 tpy. The resulting cost-effectiveness values for the 
concentrator plus RTO and concentrator plus biological treatment are 
$54,000 and $62,000 per ton of HAP reduced, respectively; however, 
these dollar values only represent the cost of operating the 
concentrator and not the RTO or biological treatment process. 
Considering the high costs per ton of HAP reduced associated with only 
the operation of the rotary concentrator, we did not consider a 
concentrator and RTO or a concentrator and biological treatment to be 
cost effective for further reducing HAP emissions from leather 
finishing operations. Additional information about the assumptions and 
methodologies used in these calculations is documented in the 
memorandum titled CAA section 112(d)(6) Technology Review for the 
Leather Finishing Operations Source Category in the docket for this 
action.
    Considering the results of the technology review, we conclude that 
changes to the leather finishing operations emission limits are not 
warranted pursuant to CAA section 112(d)(6). We are, therefore, not 
proposing to make any amendments to the existing NESHAP pursuant to CAA 
section 112(d)(6). We solicit comment on our proposed decision.

D. What other actions are we proposing?

    In addition to the proposed actions described above, we are 
proposing additional revisions. We are proposing revisions to the SSM 
provisions of the MACT rule in order to ensure that they are consistent 
with the Court decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. 
Cir. 2008), which vacated two provisions that exempted sources from the 
requirement to comply with otherwise applicable CAA section 112(d) 
emission standards during periods of SSM. We also are proposing a 
process to increase the ease and efficiency of performance test data 
submittal while improving data accessibility through the use of 
electronic data reporting. Finally, we are proposing clarifications to 
the regulatory text. Our analyses and proposed changes related to these 
issues are discussed below.
1. Startup, Shutdown, and Malfunction Requirements
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the Court vacated portions of two provisions in the EPA's 
CAA section 112 regulations governing the emissions of HAP during 
periods of SSM. Specifically, the Court vacated the SSM exemption 
contained in 40 CFR 63.6(f)(1) and 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.
    The Leather Finishing NESHAP currently requires that the standards 
apply at all times, consistent with Sierra Club v. EPA. The NESHAP 
specifies in 40 CFR 63.5320(a) ``All affected sources must be in 
compliance with the requirements of this subpart at all times, 
including periods of startup, shutdown, and malfunction.'' However, the 
NESHAP includes provisions related to SSM that are not consistent with 
Sierra Club v. EPA or 40 CFR 63.5320(a). For example, Table 2 to the 
Leather Finishing NESHAP (i.e., the General Provisions applicability 
table, hereafter referred to as the ``General Provisions table to 
subpart TTTT'') incorporates all of the introductory paragraph to 40 
CFR 63.6(e), which provides that the standards do not apply at all 
times: ``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.'' 
Further, the introductory paragraph to 40 CFR 63.6(e) refers to the SSM 
plan, which is not consistent with the NESHAP's exclusion (as specified 
in the General Provisions table to subpart TTTT) of the SSM plan in 40 
CFR 63.6(e)(3), SSM recordkeeping in 40 CFR 63.10(b)(2), and SSM 
reporting in 40 CFR 63.10(d)(5). In order to remove these 
inconsistencies within the NESHAP, to clarify the EPA's original intent 
that the standards apply at all times, and to ensure that the subpart 
requirements are consistent with the court decision cited above, we are 
proposing to unincorporate all General Provisions related to the SSM 
exemption and move any applicable portion of these General Provisions 
to the NESHAP.
    As is explained in more detail below, we are proposing two 
revisions to the General Provisions table to subpart TTTT to eliminate 
two General Provisions that include rule language providing an 
exemption for periods of SSM. Additionally, we are proposing to 
eliminate language related to SSM that treats periods of startup and 
shutdown the same as periods of malfunction, as explained further 
below. Finally, we are proposing to revise the Deviation Notification 
Report and related records as they relate to malfunctions, 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.
    The current rule specifies that the standards apply at all times. 
In promulgating the original NESHAP for Leather Finishing Operations, 
the EPA took into account startup and shutdown periods by applying a 
standard based on total coating used and HAP content and requiring a 
mass balance compliance method that was applicable for all operations, 
even periods of startup and shutdown. As a result, the EPA is not 
proposing any changes to the current requirement that all standards 
apply during those periods. However, as noted above and discussed 
further below, the current rule incorporates two general provisions 
that include rule language providing an exemption for periods of SSM, 
and the rule includes language that differentiates between normal 
operations, startup and shutdown, and malfunction events in describing 
the general duty, and these provisions are not necessary or appropriate 
in light of the requirement that the standards apply at all times. 
Periods of startup, normal operations, and shutdown are all predictable 
and routine aspects of a source's operations. Malfunctions, in 
contrast, are neither predictable nor routine. Instead they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment. (40 CFR 63.2) 
(Definition of malfunction). The EPA interprets CAA section 112 as not 
requiring emissions that occur during periods of

[[Page 11330]]

malfunction to be factored into development of CAA section 112 
standards and this reading has been upheld as reasonable by the Court 
in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016). Under 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. As the Court has recognized, the phrase 
``average emissions limitation achieved by the best performing 12 
percent of'' sources ``says nothing about how the performance of the 
best units is to be calculated.'' Nat'l Ass'n of Clean Water Agencies 
v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts 
for variability in setting emissions standards, nothing in CAA section 
112 requires the Agency to consider malfunctions as part of that 
analysis. The EPA is not required to treat a malfunction in the same 
manner as the type of variation in performance that occurs during 
routine operations of a source. A malfunction is a failure of the 
source to perform in a ``normal or usual manner,'' and no statutory 
language compels the EPA to consider such events in setting CAA section 
112 standards.
    As the Court recognized in U.S. Sugar Corp, accounting for 
malfunctions in setting standards would be difficult, if not 
impossible, given the myriad different types of malfunctions that can 
occur across all sources in the category and given the difficulties 
associated with predicting or accounting for the frequency, degree, and 
duration of various malfunctions that might occur. Id. at 608 (``the 
EPA would have to conceive of a standard that could apply equally to 
the wide range of possible boiler malfunctions, ranging from an 
explosion to minor mechanical defects. Any possible standard is likely 
to be hopelessly generic to govern such a wide array of 
circumstances.''). As such, the performance of units that are 
malfunctioning is not ``reasonably'' foreseeable. See, e.g., Sierra 
Club v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999) (``The EPA typically 
has wide latitude in determining the extent of data-gathering necessary 
to solve a problem. We generally defer to an agency's decision to 
proceed on the basis of imperfect scientific information, rather than 
to `invest the resources to conduct the perfect study.' '') See also, 
Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the 
nature of things, no general limit, individual permit, or even any 
upset provision can anticipate all upset situations. After a certain 
point, the transgression of regulatory limits caused by `uncontrollable 
acts of third parties,' such as strikes, sabotage, operator 
intoxication or insanity, and a variety of other eventualities, must be 
a matter for the administrative exercise of case-by-case enforcement 
discretion, not for specification in advance by regulation.''). In 
addition, emissions during a malfunction event can be significantly 
higher than emissions at any other time of source operation. For 
example, if an air pollution control device with 99-percent removal 
goes off-line as a result of a malfunction (as might happen if, for 
example, the bags in a baghouse catch fire) and the emission unit is a 
steady state type unit that would take days to shut down, the source 
would go from 99-percent control to zero control until the control 
device was repaired. The source's emissions during the malfunction 
would be 100 times higher than during normal operations. As such, the 
emissions over a 4-day malfunction period would exceed the annual 
emissions of the source during normal operations. As this example 
illustrates, accounting for malfunctions could lead to standards that 
are not reflective of (and significantly less stringent than) levels 
that are achieved by a well-performing non-malfunctioning source. It is 
reasonable to interpret CAA section 112 to avoid such a result. The 
EPA's approach to malfunctions is consistent with CAA section 112 and 
is a reasonable interpretation of the statute.
    Although no statutory language compels the EPA to set standards for 
malfunctions, the EPA has the discretion to do so where feasible. For 
example, in the Petroleum Refinery Sector RTR, the EPA established a 
work practice standard for unique types of malfunction that result in 
releases from pressure relief devices or emergency flaring events 
because we had information to determine that such work practices 
reflected the level of control that applies to the best performing 
sources. 80 FR 75178, 75211-14 (December 1, 2015). The EPA will 
consider whether circumstances warrant setting standards for a 
particular type of malfunction and, if so, whether the EPA has 
sufficient information to identify the relevant best performing sources 
and establish a standard for such malfunctions. We also encourage 
commenters to provide any such information.
    For the Leather Finishing Operations source category, it is 
unlikely that a malfunction would result in a violation of the 
standards. There are no instances where pollution control equipment 
could malfunction because none of the four leather finishing operations 
subject to the standard use pollution control equipment. Further, the 
standards are expressed as a yearly rolling average, and compliance is 
primarily dependent on the coating's HAP composition. Therefore, a 
malfunction of process equipment is not likely to result in a violation 
of the standards, and we have no information to suggest that it is 
feasible or necessary to establish standards for any type of 
malfunction associated with leather finishing operations. We 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

[[Page 11331]]

situations. U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
a. 40 CFR 63.5320(b) General Duty
    We are proposing to revise the General Provisions table to subpart 
TTTT (table 2) entry for 40 CFR 63.6(e) by combining all of paragraph 
(e) into one row and changing the ``yes'' in column four to ``no.'' 
Section 63.6(e)(1)(i) describes the general duty to minimize emissions. 
Some of the language in that section is no longer necessary or 
appropriate in light of the existing requirement that the standards 
apply at all times, as specified in 40 CFR 63.5320(a). Additional 
language in 40 CFR 63.6(e)(1)(ii) imposes requirements that are not 
necessary if the SSM exemption does not apply. We are proposing instead 
to add general duty regulatory text at 40 CFR 63.5320(b) that reflects 
the general duty to minimize emissions while eliminating the reference 
to periods covered by an SSM exemption. The current language in 40 CFR 
63.6(e)(1)(i) characterizes what the general duty entails during 
periods of SSM. If the SSM exemption does not apply, there is no need 
to differentiate between normal operations, startup and shutdown, and 
malfunction events in describing the general duty. Therefore, the 
language the EPA is proposing for 40 CFR 63.5320(b) does not include 
that language from 40 CFR 63.6(e)(1).
b. 40 CFR 63.5360(b) Compliance With Standards
    We are proposing to eliminate the sentence ``This includes periods 
of startup, shutdown, and malfunction.'' in 40 CFR 63.5360(b), which 
refers to the requirement to report each instance in which you, a 
source, did not meet the standard. This sentence was originally 
included to clarify the EPA's intent at the time regarding the 
standards applying at all times; however, this clarifying language is 
no longer necessary or appropriate in light of the proposed new General 
Duty language discussed in section IV.D.1.a of this preamble because 
the language differentiates between normal operations, startup and 
shutdown, and malfunction events.
c. 40 CFR 63.5380 Performance Testing
    We are proposing to revise the General Provisions table to subpart 
TTTT (table 2) entry for 40 CFR 63.7(e)(1) by adding a separate row for 
40 CFR 63.7(e)(1) and specifying ``no'' in column four. Section 
63.7(e)(1) describes performance testing requirements. The EPA is 
instead proposing to add a performance testing requirement at 40 CFR 
63.5380(b). The performance testing requirements we are proposing to 
add differ from the General Provisions performance testing provisions 
in several respects. The regulatory text does not include the language 
in 40 CFR 63.7(e)(1) that restates the SSM exemption and language that 
precluded startup and shutdown periods from being considered 
``representative'' for purposes of performance testing. The proposed 
performance testing provisions will not allow performance testing 
during startup or shutdown. Note that no facilities subject to the 
Leather Finishing NESHAP will conduct a performance test because none 
use a control device to comply with the standards. Further, as in 40 
CFR 63.7(e)(1), performance tests conducted under this subpart should 
not be conducted during malfunctions because conditions during 
malfunctions are often not representative of normal operating 
conditions. However, in eliminating this reference to 40 CFR 63.7(e) in 
the General Provisions table to subpart TTTT, we are removing a 
requirement that the owner or operator make available to the 
Administrator such records ``as may be necessary to determine the 
condition of the performance test.'' The EPA is proposing to add a 
similar requirement back into the Leather Finishing NESHAP. The 
proposed language requires the owner or operator to record the process 
information that is necessary to document operating conditions during 
the test and include in such records an explanation to support that 
such conditions represent normal operation. Section 63.7(e) does not 
specifically require the information to be recorded, but the regulatory 
text the EPA is proposing to add to 40 CFR 63.5380(b) builds on that 
requirement and makes explicit the requirement to record the 
information.
d. 40 CFR 63.5430 Recordkeeping
    As discussed in section IV.D.1.e of this preamble, the EPA is 
proposing to revise the Deviation Notification Report to include two 
new reporting elements: (1) An estimate of the quantity of HAP emitted 
during the 12-month period of the report in excess of the standard, and 
(2) the cause of the events that resulted in the deviation from the 
standard (including unknown cause, if applicable). The EPA is proposing 
that any source submitting a Deviation Notification Report also keep a 
record of this information. The source would also be required to 
include a record of the actions taken to minimize emissions. 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. 
Further, the EPA is clarifying related records already required under 
40 CFR 63.5430(b) as part of the Deviation Notification Report under 40 
CFR 63.5420(b)(3), but not clearly listed, by specifically listing 
those required records in 40 CFR 63.5430(h) as: (1) The 12-month period 
in which the exceedance occurred, and, (2) each type of leather product 
process operation performed during the 12-month period in which the 
exceedance occurred.
    Finally, we are proposing to revise the General Provisions table to 
subpart TTTT (table 2) entry for 40 CFR 63.10(b)(2) to clarify the 
recordkeeping requirements for facilities that deviate from the 
standards as a result of a malfunction. In column five, we are 
proposing to replace the sentence ``Subpart TTTT has no recordkeeping 
requirements for startup, shutdown, and malfunction events'' with the 
phrase ``See Sec.  63.5360 for CMS recordkeeping requirements if there 
is a deviation from the standard.'' This revision clarifies that 
certain records (e.g., a record of the Deviation Notification Report) 
must be retained if there is a deviation from the standards due to a 
malfunction.
e. 40 CFR 63.5420 Reporting
    We are proposing to revise the General Provisions table to subpart 
TTTT (table 2) entry for 40 CFR 63.10(d)(5) to clarify the reporting 
requirements for facilities that deviate from the standards as a result 
of a malfunction. In column five, we are proposing to replace the 
sentence ``Subpart TTTT has no startup, shutdown, and malfunction 
reporting requirements'' with the sentence ``See Sec.  63.5420(b) for 
reporting requirements if there is a deviation from the standard.'' 
This revision clarifies that the Deviation Notification Report must be 
submitted if there is a deviation from the standards due to a 
malfunction. We are also proposing language that requires sources that 
fail to meet an applicable standard at any time to report the 
information concerning such events in the Deviation Notification Report 
already required under this rule. The Leather Finishing NESHAP 
currently requires this report to include (under 40 CFR 63.5420(b)(3)) 
each type of leather product process operation performed

[[Page 11332]]

during the 12-month period of the report. We are proposing a revision 
to 40 CFR 63.5420(b)(3) to clarify that this information should include 
an indication of the 12-month period of the report. We are also 
proposing that the report must contain two new reporting elements: (1) 
The cause of the events that resulted in the source failing to meet the 
standard as determined under 40 CFR 63.5330 (i.e., the compliance ratio 
exceeds 1.00) during the 12-month period (including unknown cause, if 
applicable) and (2) an estimate of the quantity of HAP (in pounds) 
emitted during the 12-month period of the report in excess of the 
standard. As required in 40 CFR 63.5330, sources must determine 
compliance on a monthly basis based on a facility-wide average. Sources 
are required to establish on a monthly basis that the compliance ratio 
for the previous 12-month period is less than or equal to 1.00. This 
compliance ratio is calculated as required in 40 CFR 63.5330 by 
dividing the ``Actual HAP Loss'' (calculated as specified in 40 CFR 
63.5335) by the ``Allowable HAP Loss'' (calculated as specified in 40 
CFR 63.5340) (see Equation 1 of 40 CFR part 63, subpart TTTT). If the 
compliance ratio for the leather finishing operation exceeds 1.00, the 
source is ``deviating from compliance with the applicable HAP emission 
limits of subpart TTTT for the previous month'' as specified in 40 CFR 
63.5330(b)(2), and is required to submit a Deviation Notification 
Report under 40 CFR 63.5420(b). We are proposing that such a source be 
required to estimate the quantity of HAP (in pounds) emitted during the 
12-month period of the report in excess of the standard by subtracting 
the ``Allowable HAP Loss'' from the ``Actual HAP Loss.'' The difference 
between these two values would be the reported estimate of the quantity 
of HAP (in pounds) emitted during the 12-month period of the report in 
excess of the standard. The EPA is proposing these requirements to 
ensure that there is adequate information to determine compliance, to 
allow the EPA to determine the severity of the failure to meet an 
applicable standard, and to provide data that may document how the 
source met the general duty to minimize emissions during a failure to 
meet an applicable standard.
f. 40 CFR 63.5460 Definitions
    We are proposing that the definition of ``Deviation'' be revised to 
remove language that was originally included to clarify the EPA's 
intent at the time regarding the standards applying at all times; 
however, it is no longer necessary or appropriate to use this language 
in light of the proposed new General Duty language discussed in section 
IV.D.1.a of this preamble because the language differentiates between 
normal operations, startup, and shutdown, and malfunction events. The 
current definition of ``Deviation'' is ``any instance in which an 
affected source subject to this subpart, or an owner or operator of 
such a source: (1) Fails to meet any requirement or obligation 
established by this subpart, including but not limited to any emission 
limits or work practice standards; or (2) fails to meet any emission 
limits, operating limits, or work practice standards in this subpart 
during startup, shutdown, or malfunction, regardless of whether or not 
such failure is permitted by this subpart.'' We are proposing to 
eliminate the second criteria for the reasons stated above. The 
proposed new definition reads: ``Deviation means any instance in which 
an affected source subject to this subpart, or an owner or operator of 
such a source, fails to meet any requirement or obligation established 
by this subpart, including, but not limited to, any emission limits or 
work practice standards.''
2. Electronic Reporting Requirements
    Through this proposal, the EPA is proposing that owners or 
operators of leather finishing operations submit electronic copies of 
required performance test reports through the EPA's Central Data 
Exchange (CDX) using the Compliance and Emissions Data Reporting 
Interface (CEDRI). The EPA believes that 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, will further assist in the 
protection of public health and the environment, and will ultimately 
result in less burden on the regulated community. Under current 
requirements, paper reports are often stored in filing cabinets or 
boxes, which make the reports more difficult to obtain and use for data 
analysis and sharing. Electronic storage of such reports make data more 
accessible for review, analysis, and sharing. 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 
affected facilities, air agencies, the EPA, and the public.
    The EPA estimates that no existing leather finishing operation 
subject to the Leather Finishing NESHAP uses a control device to comply 
with the NESHAP. As such, no existing leather finishing operation is 
required to conduct performance tests or submit test reports, or would 
be required to submit electronic copies of test reports.
    In 2011, in response to Executive Order 13563, the EPA developed a 
plan \16\ to periodically review its regulations to determine if they 
should be modified, streamlined, expanded, or repealed in an effort to 
make regulations more effective and less burdensome. The plan includes 
replacing outdated paper reporting with electronic reporting. In 
keeping with this plan and the White House's Digital Government 
Strategy,\17\ in 2013, the EPA issued an Agency-wide policy specifying 
that new regulations will require reports to be electronic to the 
maximum extent possible.\18\ By requiring electronic submission of 
specified reports in this proposed rule, the EPA is taking steps to 
implement this policy.
---------------------------------------------------------------------------

    \16\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.epa.gov/laws-regulations/documents-retrospective-review.
    \17\ 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.
    \18\ 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.
---------------------------------------------------------------------------

    The EPA Web site that stores the submitted electronic data, 
WebFIRE, is easily accessible to everyone and provides a user-friendly 
interface that any stakeholder can access. By making data readily 
available, electronic reporting increases the amount of data that can 
be used for many purposes. One example is the development of emissions 
factors. An emissions factor is a representative value that attempts to 
relate the quantity of a pollutant released to the atmosphere with an 
activity associated with the release of that pollutant (e.g., kilograms 
of particulate emitted per megagram of coal burned). Such factors 
facilitate the estimation of emissions from various sources of air 
pollution and are an important tool in developing emissions 
inventories, which in turn are the basis for numerous efforts, 
including trends analysis, regional and local scale air quality 
modeling, regulatory impact assessments, and human exposure modeling. 
Emissions factors are also widely used in regulatory applicability 
determinations and in permitting decisions.

[[Page 11333]]

    The EPA has received feedback from stakeholders asserting that many 
of the EPA's emissions factors are outdated or not representative of a 
particular industry emission source. While the EPA believes that the 
emissions factors are suitable for their intended purpose, we recognize 
that the quality of emissions factors varies based on the extent and 
quality of underlying data. We also recognize that emissions profiles 
on different pieces of equipment can change over time due to a number 
of factors (fuel changes, equipment improvements, industry work 
practices), and it is important for emissions factors to be updated to 
keep up with these changes. The EPA is currently pursuing emissions 
factor development improvements that include procedures to incorporate 
the source test data that we are proposing be submitted electronically. 
By requiring the electronic submission of the reports identified in 
this proposed action, the EPA would be able to access and use the 
submitted data to update emissions factors more quickly and 
efficiently, creating factors that are characteristic of what is 
currently representative of the relevant industry sector. Likewise, an 
increase in the number of test reports used to develop the emissions 
factors will provide more confidence that the factor is of higher 
quality and representative of the whole industry sector.
    Additionally, by making the records, data, and reports addressed in 
this proposed rulemaking readily available, the EPA, the regulated 
community, and the public will benefit when the EPA conducts its CAA-
required technology and risk-based reviews. As a result of having 
performance test reports and air emission data readily accessible, our 
ability to carry out comprehensive reviews will be improved and 
achieved within a shorter period of time. These data will provide 
useful information on control efficiencies being achieved and 
maintained in practice within a source category and across source 
categories for regulated sources and pollutants. These reports can also 
be used to inform the technology-review process by providing 
information on improvements to add-on control technology and new 
control technology.
    Under an electronic reporting system, the EPA's OAQPS would have 
air emissions and performance test data in hand; OAQPS would not have 
to collect these data from the EPA Regional offices or from delegated 
air agencies or industry sources in cases where these reports are not 
submitted to the EPA Regional offices. Thus, we anticipate fewer or 
less substantial ICRs in conjunction with prospective CAA-required 
technology and risk-based reviews may be needed. We expect this to 
result in a decrease in time spent by industry to respond to data 
collection requests. We also expect the ICRs to contain less extensive 
stack testing provisions, as we will already have stack test data 
electronically. Reduced testing requirements would be a cost savings to 
industry. The EPA should also be able to conduct these required reviews 
more quickly, as OAQPS will not have to include the ICR collection time 
in the process or spend time collecting reports from the EPA Regional 
offices. While the regulated community may benefit from a reduced 
burden of ICRs, the general public benefits from the agency's ability 
to provide these required reviews more quickly, resulting in increased 
public health and environmental protection.
    Electronic reporting minimizes submission of unnecessary or 
duplicative reports in cases where facilities report to multiple 
government agencies and the agencies opt to rely on the EPA's 
electronic reporting system to view report submissions. Where air 
agencies continue to require a paper copy of these reports and will 
accept a hard copy of the electronic report, facilities will have the 
option to print paper copies of the electronic reporting forms to 
submit to the air agencies, and, thus, minimize the time spent 
reporting to multiple agencies. Additionally, maintenance and storage 
costs associated with retaining paper records could likewise be 
minimized by replacing those records with electronic records of 
electronically submitted data and reports.
    Air agencies could benefit from more streamlined and automated 
review of the electronically submitted data. For example, because 
performance test data would be readily-available in a standard 
electronic format, air agencies would be able to review reports and 
data electronically rather than having to conduct a review of the 
reports and data manually. Having reports and associated data in 
electronic format facilitates review through the use of software 
``search'' options, as well as the downloading and analyzing of data in 
spreadsheet format. Additionally, air agencies would benefit from the 
reported data being accessible to them through the EPA's electronic 
reporting system wherever and whenever they want or need access (as 
long as they have access to the Internet). The ability to access and 
review reports electronically assists air agencies in determining 
compliance with applicable regulations more quickly and accurately, 
potentially allowing a faster response to violations, which could 
minimize harmful air emissions. This benefits both air agencies and the 
general public.
    The proposed electronic reporting of data is consistent with 
electronic data trends (e.g., electronic banking and income tax 
filing). Electronic reporting of environmental data is already common 
practice in many media offices at the EPA. The changes being proposed 
in this rulemaking are needed to continue the EPA's transition to 
electronic reporting.
    Additionally, we have identified two broad circumstances in which 
electronic reporting extensions may be provided. In both circumstances, 
the decision to accept your claim of needing additional time to report 
is within the discretion of the Administrator, and reporting should 
occur as soon as possible.
    In 40 CFR 63.5420(c)(4), we address the situation where an 
extension may be warranted due to outages of the EPA's CDX or CEDRI 
which preclude you from accessing the system and submitting required 
reports. If either the CDX or CEDRI is unavailable at any time 
beginning 5 business days prior to the date that the submission is due, 
and the unavailability prevents you from submitting a report by the 
required date, you may assert a claim of EPA system outage. We consider 
5 business days prior to the reporting deadline to be an appropriate 
timeframe because, if the system is down prior to this time, you still 
have one week to complete reporting once the system is back online. 
However, if the CDX or CEDRI is down during the week a report is due, 
we realize that this could greatly impact your ability to submit a 
required report on time. We will notify you about known outages as far 
in advance as possible by CHIEF Listserv notice, posting on the CEDRI 
Web site, and posting on the CDX Web site so that you can plan 
accordingly and still meet your reporting deadline. However, if a 
planned or unplanned outage occurs and you believe that it will affect 
or it has affected your ability to comply with an electronic reporting 
requirement, we have provided a process to assert such a claim.
    In 40 CFR 63.5420(c)(5), we address the situation where an 
extension may be warranted due to a force majeure event, which is 
defined as an event that will be or has been caused by circumstances 
beyond the control of the affected facility, its contractors, or any 
entity controlled by the affected facility that prevents you from 
complying with the requirement to submit a report electronically as 
required by this rule.

[[Page 11334]]

Examples of such events are acts of nature, acts of war or terrorism, 
or equipment failure or safety hazards beyond the control of the 
facility. If such an event occurs or is still occurring or if there are 
still linger effects of the event in the five business days prior to a 
submission deadline, we have provided a process to assert a claim of 
force majeure.
    We are proposing these potential extensions to protect facilities 
from noncompliance in cases where they cannot successfully submit a 
report by the reporting deadline for reasons outside of their control 
as described above. We are not proposing an extension for other 
instances. Facilities should register for CEDRI far in advance of the 
initial compliance date, in order to make sure that they can complete 
the identity proofing process prior to the initial compliance date. 
Additionally, we recommend facilities start developing reports early, 
in case any questions arise during the reporting process.
3. Clarifications and Correction to the Rule
    We are proposing revisions to clarify the monitoring, 
recordkeeping, and reporting requirements for control devices and the 
provisions for alternative schedules. We are also proposing one 
correction to the rule. Our proposed changes related to these issues 
are discussed below.
    Since the original Leather Finishing NESHAP was promulgated, no 
leather finishing operations have elected to use a control device to 
comply with the standards, and we do not anticipate that any facilities 
will elect to use a control device in the foreseeable future; however, 
we are taking this opportunity to propose clarifying text to assist any 
facility that elects in the future to use a control device to comply 
with the standards. Currently, the Leather Finishing NESHAP (i.e., in 
40 CFR 63.5360(a)(2)) requires facilities using a control device to 
comply with the NEHSAP to meet the requirements in ``40 CFR part 63, 
subpart SS''; however, the Leather Finishing NESHAP does not provide 
any reference to the applicable section within subpart SS. To aid a 
facility in locating the requirements in subpart SS, we are proposing 
to replace the current general reference to subpart SS with a more 
specific reference to ``40 CFR 63.982(a)(2) (subpart SS),'' which 
provides all applicable requirements for control devices (e.g., 
monitoring requirements, data reduction procedures, and recordkeeping 
and reporting requirements). This proposed change would affect both 40 
CFR 63.5360(a)(2) and 63.5430(g). We are also proposing related 
revisions to the General Provisions table to subpart TTTT (table 2). 
For table entry 40 CFR 63.8, we propose to replace the text ``Subpart 
TTTT does not require monitoring other than as specified therein'' in 
the fifth column with the text ``See Sec.  63.5360(a)(2) for monitoring 
requirements.'' For table entries 40 CFR 63.9(g), 63.10(c), and 
63.10(e), we propose to replace the text ``Subpart TTTT does not 
require CMS'' in the fifth column with the text ``See Sec.  
63.5360(a)(2) for monitoring requirements.'' These revisions would 
clarify that monitoring requirements apply if a facility were to elect 
to use a control device to comply with the standard. Further, in 40 CFR 
63.5375, we are proposing to change the rule language ``and can be used 
to comply with the HAP emission requirements of this subpart'' to ``and 
will be used to comply with the HAP emission requirements of this 
subpart'' because ``can'' could be interpreted to require a facility 
that owns a control device, which is not used to comply with the 
Leather Finishing NESHAP, but could be used to comply with the NESHAP 
(e.g., the control device is used to comply with a different regulation 
in its operating permit), to be required to conduct the performance 
test required in 40 CFR 63.5375, even though the device is not used to 
comply with the NESHAP.
    We are also proposing to clarify in two ways the language in 40 CFR 
63.5420(b)(4) regarding alternative schedules. First, by replacing 
``responsible agency'' with ``Administrator,'' because 
``Administrator'' is defined in 40 CFR 63.2 to include ``a State that 
has been delegated the authority to implement the provisions of this 
part'' (and the definition is incorporated by the Leather Finishing 
NESHAP). Second, by replacing ``does not object'' with ``approves an 
alternative schedule'' in order to require an affirmative action by the 
Administrator rather than affirmation by non-action.
    Finally, we are proposing a correction to the title of Table 2 to 
40 CFR part 63, subpart TTTT. The current title is ``Table 2 to Subpart 
TTTT of Part 63--Leather Finishing HAP Emission Limits for Determining 
the Allowable HAP Loss,'' and the proposed title is ``Table 2 to 
Subpart TTTT of Part 63--Applicability of General Provisions to Subpart 
TTTT.''

E. What compliance dates are we proposing?

    The EPA is proposing that all of the amendments being proposed in 
this action would be effective upon publication of the final rule. The 
tasks necessary for existing facilities to comply with these proposed 
amendments related to SSM periods would require no time or resources. 
No facilities will be subject to the requirement to submit reports 
electronically. Therefore, the EPA believes that existing facilities 
will be able to comply with these proposed amendments related to SSM 
periods and the use of the electronic reporting tool (ERT), as soon as 
the final rule is effective, which will be the date of publication of 
the final rule. The EPA is specifically soliciting comment and 
additional data on the burden of complying with these proposed 
amendments.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    The EPA determined that four leather finishing operations are 
currently subject to the Leather Finishing NESHAP. This determination 
was based on reviews on various online databases and information 
sources, as well as permits, company Web sites, and other online 
sources as discussed in section 3.2 of the memorandum titled Leather 
Finishing: Residual Risk Modeling File Supporting Documentation in the 
docket for this action. The EPA estimates that all four leather 
finishing operations currently subject to the Leather Finishing NESHAP 
would be affected by the proposed requirement to review the final 
rulemaking, and none of the facilities would be affected by the 
proposed revisions to recordkeeping and reporting requirements related 
to the Deviation Notification Report or electronic reporting of 
performance tests. The EPA is not currently aware of any planned or 
potential new or reconstructed leather finishing operations.

B. What are the air quality impacts?

    The EPA estimates that annual organic HAP emissions from the four 
leather finishing operations subject to the rule are approximately 22.5 
tpy. In this proposal, we recommend no new emission limits and require 
no additional controls; therefore, no air quality impacts are expected 
as a result of the proposed amendments.

[[Page 11335]]

C. What are the cost impacts?

    The four leather finishing operations subject to this proposal will 
incur costs to review the final rule. Nationwide annual costs 
associated with the proposed requirements are estimated to be a total 
of $705 for the initial year only. We believe that the four leather 
finishing operations which are known to be subject to this proposed 
rule can meet these proposed requirements without incurring additional 
capital or operational costs. Therefore, the only costs associated with 
this proposed rule are related to reviewing the rule. For further 
information on the proposed requirements for this rule, see section IV 
of this preamble. For further information on the costs associated with 
the proposed requirements of this rule, see the document titled 
Supporting Statement for Leather Finishing Operations and the 
memorandum titled Costs for the Leather Finishing Operations Source 
Category Risk and Technology Review, both in the docket for this 
action. The memorandum titled CAA section 112(d)(6) Technology Review 
for the Leather Finishing Source Category in the docket for this 
action. These documents present cost estimates associated with the 
regulatory options that were not selected for inclusion in this 
proposed rule.

D. What are the economic impacts?

    The total national cost to comply with this proposed rule is 
estimated to be $705 in 2016 dollars, which is a one-time cost that 
will be incurred in the first year following promulgation of the final 
amendments. There are no additional emission control costs or 
additional emission reductions associated with this rule. The estimated 
cost of $705 is comprised of equal costs incurred by each of the four 
affected facilities, with each facility estimated to incur one-time 
labor costs of approximately $176 in order to become familiar with the 
rule. These costs are not expected to result in business closures, 
significant price increases, or substantial profit loss. No impacts on 
employment are expected given the minimal economic impact of the action 
on the affected firms. For further information on the economic impacts 
associated with the proposed requirements of this rule, see the 
memorandum titled Proposal Economic Impact Analysis for the 
Reconsideration of the Risk and Technology Review: Leather Finishing 
Operations Source Category in the docket for this action.

E. What are the benefits?

    While the proposed amendments would not result in reductions in 
emissions of HAP, this action, if finalized, will improve 
implementation of the Leather Finishing NESHAP by clarifying the rule 
requirements as discussed in sections IV.D.1 and 3 of this preamble. 
Also, by adding electronic reporting of test reports for any control 
devices used to comply with the rule will provide the benefits 
discussed in section IV.D.2 of this preamble, including assisting state 
and local agencies that elect to use ERT to track compliance of the 
rule.

VI. Request for Comments

    We solicit comments on all aspects of 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 Web site at http://www3.epa.gov/ttn/atw/rrisk/rtrpg.html. 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 Web site, 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, 
etc.).
    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-2003-0194 (through the method described 
in the ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or 
multiple facilities, you need only submit one file for all 
facilities. The file should contain all suggested changes for all 
sources at that facility (or facilities). We request that all data 
revision comments be submitted in the form of updated 
Microsoft[supreg] Excel files that are generated by the 
Microsoft[supreg] Access file. These files are provided on the RTR 
Web site at http://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at http://www2.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 ICR document 
that the EPA prepared has been assigned EPA ICR number 1985.07. You can 
find a copy of the ICR in the docket for this rule, and it is briefly 
summarized here.
    Proposed costs are to review the final rule in the initial year. We 
are proposing no new reporting or recordkeeping requirements to the 
Leather Finishing Operations source category.
    Respondents/affected entities: Leather Finishing Operations.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart TTTT).
    Estimated number of respondents: Four leather finishing operations.
    Frequency of response: Initially.
    Total estimated burden: 9 hours (per year) for the responding 
facilities and 0 hours (per year) for the Agency.
    Total estimated cost: $705 (per year).
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information

[[Page 11336]]

unless it displays a currently valid OMB control number. The OMB 
control numbers for the EPA's regulations in 40 CFR are listed in 40 
CFR part 9.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to [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 April 13, 2018. 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. The 
small entities subject to the requirements of this action are small 
businesses. The Agency has determined that each of the three small 
entities impacted by this action may experience an impact of less than 
0.01 percent of sales. Details of this analysis are presented in the 
memorandum titled Proposal Economic Impact Analysis for the 
Reconsideration of the Risk and Technology Review: Leather Finishing 
Operations Source Category in the docket for this action.

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 leather finishing operations industry that would 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 and IV of this preamble and further documented in the risk 
report titled Residual Risk Assessment for the Leather Finishing 
Operations Source Category in Support of the December 2017 Risk and 
Technology Review Proposed Rule in the docket for this action.

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

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

J. National Technology Transfer and Advancement Act (NTTAA)

    This action involves technical standards. Therefore, the EPA 
conducted searches for the Leather Finishing Operations Sector Risk and 
Technology Review through the Enhanced National Standards Systems 
Network Database managed by the American National Standards Institute. 
We also contacted voluntary consensus standards (VCS) organizations and 
accessed and searched their databases. We conducted searches for EPA 
Methods 24 and 311. The following VCS were identified as potentially 
acceptable alternatives to the EPA test methods for the purpose of this 
rule.
    The VCS California Air Resources Board (CARB) Method 310 
``Determination of Volatile Organic Compounds (VOC) in Consumer 
Products and Reactive Organic Compounds in Aerosol Coating Products'' 
was identified as potentially applicable for EPA Method 311. The EPA 
decided not to use this VCS because the method is impractical as an 
alternative to EPA Method 311 because it targets chemicals that are VOC 
and are not HAP.
    Five VCS were identified as potentially applicable for EPA Method 
24, as follows:

     ASTM D2369-01 ``Standard Test Method for Volatile 
Content of Coatings'';
     ASTM D2697-86 (1998) ``Standard Test Method for Volume 
Nonvolatile Matter in Clear or Pigmented Coatings'';
     ASTM D6093-97 (Reapproved 2003) ``Standard Test Method 
for Percent Volume Nonvolatile Matter in Clear or Pigmented Coatings 
Using a Helium Gas Pycnometer'';
     ASTM D2111-95 (2000) ``Standard Test Methods for 
Specific Gravity and Density of Halogenated Organic Solvents and 
Their Admixtures''; and
     ASTM D1963-85 (1996) Standard Test Method for Specific 
Gravity of Drying Oils, Varnishes, Resins, and Related Materials at 
25/25[deg]C.

    The EPA is proposing not to use these methods. The use of ASTM 
D2369-01, ASTM D2697-86 (1998), ASTM D6093-97 (Reapproved 2003), and 
ASTM D1963-85 (1996) would be impractical for this NESHAP because they 
address only a portion of Method 24 and do not address density, which 
is the only portion of Method 24 used for compliance with the Leather 
Finishing NESHAP. Further, though ASTM D2111-95 (2000), ``Standard Test 
Methods for Specific Gravity and Density of Halogenated Organic 
Solvents and Their Admixtures,'' provides an alternative method for 
measuring density, this version of the ASTM method has expired. A 
thorough summary of the search conducted and results are included in 
the memorandum titled Voluntary Consensus Standard Results for National 
Emission Standards for Hazardous Air Pollutants for Leather Finishing 
Operations in the docket for this action.

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 (58 FR 7629, February 16, 1994).
    The documentation for this decision is contained in section IV.A of 
this preamble and the technical report titled Risk and Technology 
Review--Analysis of Demographic Factors for Populations Living Near 
Leather Finishing Operations in the docket for this action.
    As discussed in section IV.A of this preamble, we performed a 
demographic analysis, 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 this analysis, we evaluated the distribution 
of HAP-related cancer risks and

[[Page 11337]]

noncancer hazards from the leather finishing operations across 
different social, demographic, and economic groups within the 
populations living near operations identified as having the highest 
risks.
    The analysis indicates that the minority population living within 
50 km (4,632,781 people, of which 25 percent are minority) and within 5 
km (158,482 people, of which 13 percent are minority) of the four 
leather finishing operations facilities is less than the minority 
population found nationwide (38 percent). The proximity results 
indicate that the population percentage for the ``Native American'' 
demographic group within 5 km of leather finishing operations emissions 
is slightly greater than the corresponding nationwide percentage for 
that same demographic. The percentage of people ages 65 and older 
residing within 5 km of leather finishing operations (18 percent) is 4 
percentage points higher than the corresponding nationwide percentage 
(14 percent). The other demographic groups included in the assessment 
within 5 km of leather finishing operations emissions were the same or 
lower than the corresponding nationwide percentages.
    When examining the cancer risk levels of those exposed to emissions 
from the four leather finishing operations, we find that there are no 
people within a 50-km radius of modeled facilities exposed to a cancer 
risk greater than or equal to 1-in-1 million as a result of emissions 
from leather finishing operations. When examining the noncancer risk 
levels, we find that there are no people within a 50-km radius of 
modeled facilities exposed to a noncancer risk (in this analysis, 
reproductive HI) greater than 1 as a result of emissions from leather 
finishing operations.
    The EPA has determined that this proposed rule does not have 
disproportionately high and adverse human health or environmental 
effects on minority populations, low-income populations, and/or 
indigenous peoples because the health risks based on actual emissions 
are low (below 2-in-1 million), the population exposed to risks greater 
than 1-in-1 million is relatively small (750 persons), and the rule 
maintains or increases the level of environmental protection for all 
affected populations without having any disproportionately high and 
adverse human health or environmental effects on any population, 
including any minority, low-income, or indigenous populations. Further, 
the EPA believes that implementation of this rule will provide an ample 
margin of safety to protect public health of all demographic groups.

List of Subjects in 40 CFR Part 63

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

    Dated: February 28, 2018.
E. Scott Pruitt,
Administrator.
    For the reasons set out in the preamble, the Environmental 
Protection Agency proposes to amend title 40, chapter I, part 63 of the 
Code of Federal Regulations as follows:

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

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

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

Subpart TTTT--National Emission Standards for Hazardous Air 
Pollutants for Leather Finishing Operations

0
2. Section 63.5320 is amended by revising paragraphs (a) and (b) to 
read as follows:


Sec.  63.5320  How does my affected major source comply with the HAP 
emission standards?

    (a) All affected sources must be in compliance with the 
requirements of this subpart at all times.
    (b) At all times, the owner or operator must operate and maintain 
any affected source, including associated air pollution control 
equipment and monitoring equipment, in a manner consistent with safety 
and good air pollution control practices for minimizing emissions. The 
general duty to minimize emissions does not require the owner or 
operator to make any further efforts to reduce emissions if levels 
required by the applicable standard have been achieved. Determination 
of whether a source is operating in compliance with operation and 
maintenance requirements will be based on information available to the 
Administrator that may include, but is not limited to, monitoring 
results, review of operation and maintenance procedures, review of 
operation and maintenance records, and inspection of the affected 
source.
* * * * *
0
3. Section 63.5360 is amended by revising paragraphs (a)(2) and (b) to 
read as follows:


Sec.  63.5360  How do I demonstrate continuous compliance with the 
emission standards?

    (a) * * *
    (2) If you use an emission control device, you must comply with 40 
CFR part 63.982(a)(2) (subpart SS) and collect the monitoring data as 
specified therein.
* * * * *
    (b) You must report each instance in which you did not meet the 
emission standards in Sec.  63.5305. These deviations must be reported 
according to the requirements in Sec.  63.5420(b).
* * * * *
0
4. Section 63.5375 is revised to read as follows:


Sec.  63.5375  When must I conduct a performance test or initial 
compliance demonstration?

    You must conduct performance tests after the installation of any 
emission control device that reduces HAP emissions and will be used to 
comply with the HAP emission requirements of this subpart. You must 
complete your performance tests not later than 60 calendar days before 
the end of the 12-month period used in the initial compliance 
determination.
0
5. Section 63.5380 is amended by revising paragraphs (a) and (b) to 
read as follows:


Sec.  63.5380  How do I conduct performance tests?

    (a) Each performance test must be conducted according to the 
requirements in Sec.  63.7(e)(2) through (4) and the procedures of 
Sec.  63.997(e)(1) and (2).
    (b) Performance tests shall be conducted under such conditions as 
the Administrator specifies to the owner or operator based on 
representative performance of the affected source for the period being 
tested. Representative conditions exclude periods of startup and 
shutdown. The owner or operator may not conduct performance tests 
during periods of malfunction. The owner or operator must record the 
process information that is necessary to document operating conditions 
during the test and include in such record an explanation to support 
that such conditions represent normal operation. Upon request, the 
owner or operator shall make available to the Administrator such 
records as may be necessary to determine the conditions of performance 
tests.
* * * * *
0
6. Section 63.5420 is amended by revising the introductory text of 
paragraph (b) and paragraphs (b)(3) and

[[Page 11338]]

(4), and adding paragraphs (b)(5), (b)(6), and (c) to read as follows:


Sec.  63.5420  What reports must I submit and when?

* * * * *
    (b) You must submit a Deviation Notification Report for each 
compliance determination you make in which the compliance ratio exceeds 
1.00, as determined under Sec.  63.5330. Submit the deviation report by 
the fifteenth of the following month in which you determined the 
deviation from the compliance ratio. The Deviation Notification Report 
must include the items in paragraphs (b)(1) through (6) of this 
section:
* * * * *
    (3) The 12-month period covered by the report and each type of 
leather product process operation performed during the 12-month period.
    (4) The compliance ratio comprising the deviation. You may reduce 
the frequency of submittal of the Deviation Notification Report if the 
Administrator of these NESHAP approves an alternative schedule.
    (5) An estimate of the quantity of HAP (in pounds) emitted during 
the 12 months specified in paragraph (b)(3) of this section in excess 
of the allowable HAP loss. Calculate this estimate of excess emissions 
by subtracting the allowable HAP loss determined as specified in Sec.  
63.5340 from the actual HAP loss determined as specified in Sec.  
63.5335.
    (6) The cause of the events that resulted in the source failing to 
meet an applicable standard (including unknown cause, if applicable).
    (c) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2) required by this subpart, you must 
submit the results of the performance test following the procedures 
specified in paragraphs (c)(1) through (3) of this section.
    (1) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT website 
(https://www.epa.gov/electronicreporting-air-emissions/electronicreporting-tool-ert) at the time of the test, you must submit 
the results of the performance test to the EPA via the Compliance and 
Emissions Data Reporting Interface (CEDRI). (CEDRI can be accessed 
through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/).) 
Performance test data must be submitted in a file format generated 
through the use of the EPA's ERT or an alternate electronic file format 
consistent with the extensible markup language (XML) schema listed on 
the EPA's ERT website.
    (2) For data collected using test methods that are not supported by 
the EPA's ERT as listed on the EPA's ERT website at the time of the 
test, you must submit the results of the performance test to the 
Administrator at the appropriate address listed in Sec.  63.13 unless 
the Administrator agrees to or specifies an alternate reporting method.
    (3) If you claim that some of the performance test information 
being submitted under paragraph (c)(1) is confidential business 
information (CBI), you must submit a complete file generated through 
the use of the EPA's ERT or an alternate electronic file consistent 
with the XML schema listed on the EPA's ERT website, including 
information claimed to be CBI, on a compact disc, flash drive or other 
commonly used electronic storage medium to the EPA. The electronic 
medium must be clearly marked as CBI and mailed to U.S. EPA/OAQPS/CORE 
CBI Office, Attention: Group Leader, Measurement Policy Group, MD C404-
02, 4930 Old Page Rd., Durham, NC 27703. The same ERT or alternate file 
with the CBI omitted must be submitted to the EPA via the EPA's CDX as 
described in paragraph (c)(1) of this section.
    (4) If you are required to electronically submit a report through 
the Compliance and Emissions Data Reporting Interface (CEDRI) in the 
EPA's Central Data Exchange (CDX), and due to a planned or actual 
outage of either the EPA's CEDRI or CDX systems within the period of 
time beginning 5 business days prior to the date that the submission is 
due, you will be or are precluded from accessing CEDRI or CDX and 
submitting a required report within the time prescribed, you may assert 
a claim of EPA system outage for failure to timely comply with the 
reporting requirement. You must submit notification to the 
Administrator in writing as soon as possible following the date you 
first knew, or through due diligence should have known, that the event 
may cause or caused a delay in reporting. You must provide to the 
Administrator a written description identifying the date, time and 
length of the outage; a rationale for attributing the delay in 
reporting beyond the regulatory deadline to the EPA system outage; 
describe the measures taken or to be taken to minimize the delay in 
reporting; and identify a date by which you propose to report, or if 
you have already met the reporting requirement at the time of the 
notification, the date you reported. In any circumstance, the report 
must be submitted electronically as soon as possible after the outage 
is resolved. The decision to accept the claim of EPA system outage and 
allow an extension to the reporting deadline is solely within the 
discretion of the Administrator.
    (5) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX and a force majeure event is about to occur, 
occurs, or has occurred or there are lingering effects from such an 
event within the period of time beginning 5 business days prior to the 
date the submission is due, the owner or operator may assert a claim of 
force majeure for failure to timely comply with the reporting 
requirement. For the purposes of this section, a force majeure event is 
defined as an event that will be or has been caused by circumstances 
beyond the control of the affected facility, its contractors, or any 
entity controlled by the affected facility that prevents you from 
complying with the requirement to submit a report electronically within 
the time period prescribed. Examples of such events are acts of nature 
(e.g., hurricanes, earthquakes, or floods), acts of war or terrorism, 
or equipment failure or safety hazard beyond the control of the 
affected facility (e.g., large scale power outage). If you intend to 
assert a claim of force majeure, you must submit notification to the 
Administrator in writing as soon as possible following the date you 
first knew, or through due diligence should have known, that the event 
may cause or caused a delay in reporting. You must provide to the 
Administrator a written description of the force majeure event and a 
rationale for attributing the delay in reporting beyond the regulatory 
deadline to the force majeure event; describe the measures taken or to 
be taken to minimize the delay in reporting; and identify a date by 
which you propose to report, or if you have already met the reporting 
requirement at the time of the notification, the date you reported. In 
any circumstance, the reporting must occur as soon as possible after 
the force majeure event occurs. The decision to accept the claim of 
force majeure and allow an extension to the reporting deadline is 
solely within the discretion of the Administrator.
0
7. Section 63.5430 is amended by revising the introductory text and 
paragraph (g), and adding paragraphs (h) and (i) to read as follows:


Sec.  63.5430  What records must I keep?

    You must satisfy the recordkeeping requirements in paragraphs (a) 
through (i) of this section by the compliance date specified in Sec.  
63.5295.
* * * * *

[[Page 11339]]

    (g) If you use an emission control device, you must keep records of 
monitoring data as specified at Sec.  63.982(a)(2) (subpart SS).
    (h) In the event that the compliance ratio exceeded 1.00, as 
determined under Sec.  63.5330, keep a record of the information 
specified in paragraphs (h)(1) through (5) of this section for each 
exceedance.
    (1) The 12-month period in which the exceedance occurred, as 
reported in Sec.  63.5420(b).
    (2) Each type of leather product process operation performed during 
the 12-month period in which the exceedance occurred, as reported in 
Sec.  63.5420(b).
    (3) Estimate of the quantity of HAP (in pounds) emitted during the 
12 months specified in Sec.  63.5420(b)(3) in excess of the allowable 
HAP loss, as reported in Sec.  63.5420(b).
    (4) Cause of the events that resulted in the source failing to meet 
an applicable standard (including unknown cause, if applicable), as 
reported in Sec.  63.5420(b).
    (5) Actions taken to minimize emissions in accordance with Sec.  
63.5320(b), and any corrective actions taken to return the affected 
unit to its normal or usual manner of operation.
    (i) Any records required to be maintained by this part that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.
0
8. Section 63.5460 is amended by revising the definition for 
``Deviation'' to read as follows:


Sec.  63.5460  What definitions apply to this subpart?

* * * * *
    Deviation means any instance in which an affected source subject to 
this subpart, or an owner or operator of such a source fails to meet 
any requirement or obligation established by this subpart, including, 
but not limited to, any emission limits or work practice standards.
* * * * *
0
9. Table 2 to Subpart TTTT of Part 63 is revised to read as follows:

Table 2 to Subpart TTTT of Part 63--Applicability of General Provisions 
to Subpart TTTT

    As required in Sec.  63.5450, you must meet the appropriate NESHAP 
General Provision requirements in the following table:

----------------------------------------------------------------------------------------------------------------
                                   Subject of      Brief description of     Applies to
  General provisions citation       citation           requirement            subpart           Explanation
----------------------------------------------------------------------------------------------------------------
Sec.   63.1...................  Applicability...  Initial applicability  Yes.              .....................
                                                   determination;
                                                   applicability after
                                                   standard
                                                   established; permit
                                                   requirements;
                                                   extensions,
                                                   notifications.
Sec.   63.2...................  Definitions.....  Definitions for Part   Yes.............  Except as
                                                   63 standards.                            specifically
                                                                                            provided in this
                                                                                            subpart.
Sec.   63.3...................  Units and         Units and              Yes.              .....................
                                 abbreviations.    abbreviations for
                                                   Part 63 standards.
Sec.   63.4...................  Prohibited        Prohibited             Yes.              .....................
                                 activities and    activities;
                                 circumvention.    compliance date;
                                                   circumvention,
                                                   severability.
Sec.   63.5...................  Construction/     Applicability;         Yes.............  Except for paragraphs
                                 reconstruction.   applications;                            of Sec.   63.5 as
                                                   approvals.                               listed below.
Sec.   63.5(c)................  [Reserved].                                                .....................
Sec.   63.5(d)(1)(ii)(H)......  Application for   Type and quantity of   No..............  All sources emit HAP.
                                 approval.         HAP, operating                           Subpart TTTT does
                                                   parameters.                              not require control
                                                                                            from specific
                                                                                            emission points.
Sec.   63.5(d)(1)(i)..........  [Reserved].                                                .....................
Sec.   63.5(d)(1)(iii),         ................  Application for        No..............  The requirements of
 (d)(2), (d)(3)(ii).                               approval.                                the application for
                                                                                            approval for new and
                                                                                            reconstructed
                                                                                            sources are
                                                                                            described in Sec.
                                                                                            63.5320(b). General
                                                                                            provision
                                                                                            requirements for
                                                                                            identification of
                                                                                            HAP emission points
                                                                                            or estimates of
                                                                                            actual emissions are
                                                                                            not required.
                                                                                            Descriptions of
                                                                                            control and methods,
                                                                                            and the estimated
                                                                                            and actual control
                                                                                            efficiency of such
                                                                                            do not apply.
                                                                                            Requirements for
                                                                                            describing control
                                                                                            equipment and the
                                                                                            estimated and actual
                                                                                            control efficiency
                                                                                            of such equipment
                                                                                            apply only to
                                                                                            control equipment to
                                                                                            which the subpart
                                                                                            TTTT requirements
                                                                                            for quantifying
                                                                                            solvent destroyed by
                                                                                            an add-on control
                                                                                            device would be
                                                                                            applicable.
Sec.   63.6...................  Applicability of  Applicability of       Yes.............  Except for paragraphs
                                 general           general provisions.                      of Sec.   63.6 as
                                 provisions.                                                listed below.
Sec.   63.6(b)(1)-(3).........  Compliance        .....................  No..............  Section Sec.
                                 dates, new and                                             63.5283 specifies
                                 reconstructed                                              the compliance dates
                                 sources.                                                   for new and
                                                                                            reconstructed
                                                                                            sources.
Sec.   63.6(b)(6).............  [Reserved].                                                .....................
Sec.   63.6(c)(3)-(4).........  [Reserved].                                                .....................
Sec.   63.6(d)................  [Reserved].                                                .....................
Sec.   63.6(e)(1).............  Operation and     .....................  No..............  See Sec.   63.5320(b)
                                 maintenance                                                for general duty
                                 requirements.                                              requirement.
Sec.   63.6(e)(2).............  [Reserved].                                                .....................

[[Page 11340]]

 
Sec.   63.6(e)(3).............  Operation and     Startup, shutdown,     No..............  Subpart TTTT does not
                                 maintenance       and malfunction plan                     have any startup,
                                 requirements.     requirements.                            shutdown, and
                                                                                            malfunction plan
                                                                                            requirements.
Sec.   63.6(f)-(g)............  Compliance with   Comply with emission   No..............  Subpart TTTT does not
                                 nonopacity        standards at all                         have nonopacity
                                 emission          times except during                      requirements.
                                 standards         SSM.
                                 except during
                                 SSM.
Sec.   63.6(h)................  Opacity/visible   .....................  No..............  Subpart TTTT has no
                                 emission (VE)                                              opacity or visual
                                 standards.                                                 emission standards.
Sec.   63.6(i)................  Compliance        Procedures and         Yes.              .....................
                                 extension.        criteria for
                                                   responsible agency
                                                   to grant compliance
                                                   extension.
Sec.   63.6(j)................  Presidential      President may exempt   Yes.              .....................
                                 compliance        source category from
                                 exemption.        requirement to
                                                   comply with subpart.
Sec.   63.7...................  Performance       Schedule, conditions,  Yes.............  Except for paragraphs
                                 testing           notifications and                        of Sec.   63.7 as
                                 requirements.     procedures.                              listed below.
                                                                                            Subpart TTTT
                                                                                            requires performance
                                                                                            testing only if the
                                                                                            source applies
                                                                                            additional control
                                                                                            that destroys
                                                                                            solvent. Sec.
                                                                                            63.5311 requires
                                                                                            sources to follow
                                                                                            the performance
                                                                                            testing guidelines
                                                                                            of the General
                                                                                            Provisions if a
                                                                                            control is added.
Sec.   63.7(a)(2) (i) and       Performance       Applicability and      No..............  Sec.   63.5310(a) of
 (iii).                          testing           performance dates.                       subpart TTTT
                                 requirements.                                              specifies the
                                                                                            requirements of
                                                                                            performance testing
                                                                                            dates for new and
                                                                                            existing sources.
Sec.   63.7(e)(1).............  Conduct of        Defines                No..............  See Sec.   63.5380.
                                 performance       representative
                                 tests.            conditions; provides
                                                   an exemption from
                                                   the standards for
                                                   periods of startup,
                                                   shutdown, and
                                                   malfunction;
                                                   requires that, upon
                                                   request, the owner
                                                   or operator shall
                                                   make available to
                                                   the Administrator
                                                   such records as may
                                                   be necessary to
                                                   determine the
                                                   conditions of
                                                   performance tests.
Sec.   63.8...................  Monitoring        Applicability,         No..............  See Sec.
                                 requirements.     conduct of                               63.5360(a)(2) for
                                                   monitoring,                              monitoring
                                                   operation and                            requirements.
                                                   maintenance, quality
                                                   control, performance
                                                   evaluations, use of
                                                   alternative
                                                   monitoring method,
                                                   reduction of
                                                   monitoring data.
Sec.   63.9...................  Notification      Applicability and      Yes.............  Except for paragraphs
                                 requirements.     State delegation.                        of Sec.   63.9 as
                                                                                            listed below.
Sec.   63.9(e)................  Notification of   Notify responsible     Yes.............  Applies only if
                                 performance       agency 60 days ahead.                    performance testing
                                 test.                                                      is performed.
Sec.   63.9(f)................  Notification of   Notify responsible     No..............  Subpart TTTT has no
                                 VE/opacity        agency 30 days ahead.                    opacity or visual
                                 observations.                                              emission standards.
Sec.   63.9(g)................  Additional        Notification of        No..............  See Sec.
                                 notifications     performance                              63.5360(a)(2) for
                                 when using a      evaluation;                              CMS requirements.
                                 continuous        notification using
                                 monitoring        COMS data;
                                 system (CMS).     notification that
                                                   exceeded criterion
                                                   for relative
                                                   accuracy.
Sec.   63.9(h)................  Notification of   Contents.............  No..............  Sec.   63.5320(d)
                                 compliance                                                 specifies
                                 status.                                                    requirements for the
                                                                                            notification of
                                                                                            compliance status.
Sec.   63.10..................  Recordkeeping/    Schedule for           Yes.............  Except for paragraphs
                                 reporting.        reporting, record                        of Sec.   63.10 as
                                                   storage.                                 listed below.
Sec.   63.10(b)(2)............  Recordkeeping...  CMS recordkeeping;     No..............  See Sec.   63.5360
                                                   CMS records of                           for CMS
                                                   startup, shutdown,                       recordkeeping
                                                   and malfunction                          requirements, except
                                                   events.                                  see 63.5430(h) for
                                                                                            CMS recordkeeping
                                                                                            requirements if
                                                                                            there is a deviation
                                                                                            from the standard.
Sec.   63.10(c)...............  Recordkeeping...  Additional CMS         No..............  See Sec.
                                                   recordkeeping.                           63.5360(a)(2) for
                                                                                            CMS recordkeeping
                                                                                            requirements.
Sec.   63.10(d)(2)............  Reporting.......  Reporting performance  Yes.............  Applies only if
                                                   test results.                            performance testing
                                                                                            is performed.
Sec.   63.10(d)(3)............  Reporting.......  Reporting opacity or   No..............  Subpart TTTT has no
                                                   VE observations.                         opacity or visible
                                                                                            emission standards.
Sec.   63.10(d)(4)............  Reporting.......  Progress reports.....  Yes.............  Applies if a
                                                                                            condition of
                                                                                            compliance
                                                                                            extension.
Sec.   63.10(d)(5)............  Reporting.......  Startup, shutdown,     No..............  See Sec.   63.5420(b)
                                                   and malfunction                          for reporting
                                                   reporting.                               requirements if
                                                                                            there is a deviation
                                                                                            from the standard.

[[Page 11341]]

 
Sec.   63.10(e)...............  Reporting.......  Additional CMS         No..............  See Sec.
                                                   reports.                                 63.5360(a)(2) for
                                                                                            monitoring
                                                                                            requirements.
Sec.   63.11..................  Control device    Requirements for       Yes.............  Applies only if your
                                 requirements.     flares.                                  source uses a flare
                                                                                            to control solvent
                                                                                            emissions. Subpart
                                                                                            TTTT does not
                                                                                            require flares.
Sec.   63.12..................  State authority   State authority to     Yes.              .....................
                                 and delegations.  enforce standards.
Sec.   63.13..................  State/regional    Addresses where        Yes.              .....................
                                 addresses.        reports,
                                                   notifications, and
                                                   requests are sent.
Sec.   63.14..................  Incorporation by  Test methods           Yes.              .....................
                                 reference.        incorporated by
                                                   reference.
Sec.   63.15..................  Availability of   Public and             Yes.              .....................
                                 information and   confidential
                                 confidentiality.  information.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2018-04939 Filed 3-13-18; 8:45 am]
 BILLING CODE 6560-50-P