[Federal Register Volume 84, Number 23 (Monday, February 4, 2019)]
[Proposed Rules]
[Pages 1570-1597]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-28322]



[[Page 1569]]

Vol. 84

Monday,

No. 23

February 4, 2019

Part III





Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Hydrochloric 
Acid Production Residual Risk and Technology Review; Proposed Rules

Federal Register / Vol. 84 , No. 23 / Monday, February 4, 2019 / 
Proposed Rules

[[Page 1570]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2018-0417; FRL-9988-70-OAR]
RIN 2060-AT74


National Emission Standards for Hazardous Air Pollutants: 
Hydrochloric Acid Production 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 the Hydrochloric Acid (HCl) Production source 
category. The proposed action presents the results of the residual risk 
and technology reviews (RTRs) conducted as required under the Clean Air 
Act (CAA). The proposed amendments address the startup, shutdown, and 
malfunction (SSM) provisions of the rule, add electronic reporting, and 
update the reporting and recordkeeping requirements.

DATES:  Comments. Comments must be received on or before March 21, 
2019. Under the Paperwork Reduction Act (PRA), comments on the 
information collection provisions are best assured of consideration if 
the Office of Management and Budget (OMB) receives a copy of your 
comments on or before March 6, 2019.
    Public Hearing. If anyone contacts us requesting a public hearing 
on or before February 11, 2019, we will hold a hearing. Additional 
information about the hearing, if requested, will be published in a 
subsequent Federal Register document and posted at https://www.epa.gov/stationary-sources-air-pollution/hydrochloric-acid-production-national-emission-standards-hazardous. See SUPPLEMENTARY INFORMATION for 
information on requesting and registering for a public hearing.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2018-0417, at https://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. See SUPPLEMENTARY 
INFORMATION for detail about how the EPA treats submitted comments. 
Regulations.gov is our preferred method of receiving comments. However, 
the following other submission methods are also accepted:
    <bullet> Email: <a href="/cdn-cgi/l/email-protection#e485c9858a80c996c9808b878f8190a4819485ca838b92"><span class="__cf_email__" data-cfemail="056428646b61287728616a666e6071456075642b626a73">[email protected]</span></a>. Include Docket ID No. EPA-
HQ-OAR-2018-0417 in the subject line of the message.
    <bullet> Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2018-0417.
    <bullet> Mail: 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-2018-0417, Mail 
Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460.
    <bullet> Hand/Courier Delivery: 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.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Nathan Topham, Sector Policies and Programs Division 
(Mail Code D243-02), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-0483; fax number: (919) 541-4991; 
and email address: <a href="/cdn-cgi/l/email-protection#661209160e070b480807120e07082603160748010910"><span class="__cf_email__" data-cfemail="01756e7169606c2f6f607569606f416471602f666e77">[email protected]</span></a>. For specific information 
regarding the risk modeling methodology, contact Terri Hollingsworth, 
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) 
541-2076; fax number: (919) 541-0840; and email address: 
<a href="/cdn-cgi/l/email-protection#472f282b2b2e292034302835332f69332235352e0722372669202831"><span class="__cf_email__" data-cfemail="90f8fffcfcf9fef7e3e7ffe2e4f8bee4f5e2e2f9d0f5e0f1bef7ffe6">[email protected]</span></a>. For information about the applicability of 
the NESHAP to a particular entity, contact Marcia Mia, Office of 
Enforcement and Compliance Assurance, U.S. Environmental Protection 
Agency, EPA WJC South Building (Mail Code 2227A), 1200 Pennsylvania 
Avenue NW, Washington, DC 20460; telephone number: (202) 564-7042; and 
email address: <a href="/cdn-cgi/l/email-protection#305d59511e5d5142535951705540511e575f46"><span class="__cf_email__" data-cfemail="f8959199d695998a9b9199b89d8899d69f978e">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 
    Public hearing. Please contact Adrian Gates at (919) 541-4860 or by 
email at <a href="/cdn-cgi/l/email-protection#98fff9ecfdebb6f9fceaf1f9f6d8fde8f9b6fff7ee"><span class="__cf_email__" data-cfemail="b4d3d5c0d1c79ad5d0c6ddd5daf4d1c4d59ad3dbc2">[email protected]</span></a> to request a public hearing, to register 
to speak at the public hearing, or to inquire as to whether a public 
hearing will be held.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2018-0417. All documents in the docket are 
listed in Regulations.gov. Although listed, some information is not 
publicly available, e.g., confidential business information (CBI) or 
other information whose disclosure is restricted by statute. Certain 
other material, such as copyrighted material, is not placed on the 
internet and will be publicly available only in hard copy. Publicly 
available docket materials are available either electronically in 
Regulations.gov or in hard copy at the EPA Docket Center, Room 3334, 
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-
2018-0417. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit information that you consider to be CBI or 
otherwise protected through https://www.regulations.gov or email. This 
type of information should be submitted by mail as discussed below.
    The EPA may publish any comment received to its public docket. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the Web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov, your email

[[Page 1571]]

address will be automatically captured and included as part of the 
comment that is placed in the public docket and made available on the 
internet. If you submit an electronic comment, the EPA recommends that 
you include your name and other contact information in the body of your 
comment and with any digital storage media you submit. If the EPA 
cannot read your comment due to technical difficulties and cannot 
contact you for clarification, the EPA may not be able to consider your 
comment. Electronic files should not include special characters or any 
form of encryption and be free of any defects or viruses. For 
additional information about the EPA's public docket, visit the EPA 
Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
any digital storage media that you mail to the EPA, mark the outside of 
the digital storage media as CBI and then identify electronically 
within the digital storage media the specific information that is 
claimed as CBI. In addition to one complete version of the comments 
that includes information claimed as CBI, you must submit a copy of the 
comments that does not contain the information claimed as CBI directly 
to the public docket through the procedures outlined in Instructions 
above. If you submit any digital storage media that does not contain 
CBI, mark the outside of the digital storage media clearly that it does 
not contain CBI. Information not marked as CBI will be included in the 
public docket and the EPA's electronic public docket without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 Code of Federal Regulations 
(CFR) part 2. Send or deliver information identified as CBI only to the 
following address: OAQPS Document Control Officer (C404-02), OAQPS, 
U.S. Environmental Protection Agency, Research Triangle Park, North 
Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2018-0417.
    Preamble Acronyms and Abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines the following terms and acronyms here:

AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM-3 model
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CFR Code of Federal Regulations
Cl<INF>2</INF> chlorine
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guideline
ERT Electronic Reporting Tool
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM-3 Human Exposure Model, Version 1.1.0
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
IRIS Integrated Risk Information System
km kilometer
MACT maximum achievable control technology
mg/m\3\ milligrams per cubic meter
MIR maximum individual risk
NAAQS National Ambient Air Quality Standards
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
OECA Office of Enforcement and Compliance Assurance
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
POM polycyclic organic matter
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
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
TRIM.FaTE Total Risk Integrated Methodology: Fate, Transport, and 
Ecological Exposure model
UF uncertainty factor
UMRA Unfunded Mandates Reform Act
URE unit risk estimate

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
III. Analytical Procedures and Decision-Making
    A. How do we consider risk in our decision-making?
    B. How do we perform the technology review?
    C. How do we estimate post-MACT risk posed by the source 
category?
IV. Analytical Results and Proposed Decisions
    A. What are the results of the risk assessment and analyses?
    B. What are our proposed decisions regarding risk acceptability, 
ample margin of safety, and adverse environmental effect?
    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 Regulation and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA)
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source categories that are 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 will not be affected by this proposed action. As 
defined in the Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576, 
July 16, 1992) and

[[Page 1572]]

Documentation for Developing the Initial Source Category List (see EPA-
450/3-91-030), the HCl Production source category includes any facility 
engaged in the production of HCl. The category includes, but is not 
limited to, production of hydrochloric acid via any of the following 
methods: (1) Production of HCl as a by-product in the manufacture of 
organic chemicals; (2) direct reaction of salts and sulfuric acid 
(Mannheim process); (3) reaction of a salt, sulfur dioxide, oxygen, and 
water (Hargreaves process); or (4) burning chlorine (Cl<INF>2</INF>) in 
the presence of hydrogen gas. On September 18, 2001 (66 FR 48174), the 
Fume Silica Production source category was combined with the HCl 
Production source category. The Fume Silica Production source category 
is any facility engaged in the production of fume silica. Fume silica 
is a fine white powder used as a thickener, thixotropic, or reinforcing 
agent in inks, resins, rubber, paints, and cosmetics. The category 
includes the production of fume silica by the combustion of silicon 
tetrachloride in hydrogen-oxygen furnaces.

    Table 1--NESHAP and Industrial Source Categories Affected by This
                             Proposed Action
------------------------------------------------------------------------
          Source category                  NESHAP         NAICS code \1\
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HCl production and fume silica      HCl.................          325180
 production.
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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 
https://www.epa.gov/hydrochloric-acid-production-national-emission-standards-hazardous. Following publication in the Federal Register, the 
EPA will post the Federal Register version of the proposal and key 
technical documents at this same website. Information on the overall 
residual RTR program is available at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A redline version of the regulatory language that incorporates the 
proposed changes in this action is available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2018-0417).

II. Background

A. What is the statutory authority for this action?

    The statutory authority for this action is provided by sections 112 
and 301 of the CAA, as amended (42 U.S.C. 7401 et seq.). Section 112 of 
the CAA establishes a two-stage regulatory process to develop standards 
for emissions of hazardous air pollutants (HAP) from stationary 
sources. Generally, the first stage involves establishing technology-
based standards and the second stage involves evaluating those 
standards that are based on maximum achievable control technology 
(MACT) to determine whether additional standards are needed to address 
any remaining risk associated with HAP emissions. This second stage is 
commonly referred to as the ``residual risk review.'' In addition to 
the residual risk review, the CAA also requires the EPA to review 
standards set under CAA section 112 every 8 years to determine if there 
are ``developments in practices, processes, or control technologies'' 
that may be appropriate to incorporate into the standards. This review 
is commonly referred to as the ``technology review.'' When the two 
reviews are combined into a single rulemaking, it is commonly referred 
to as the ``risk and technology review.'' The discussion that follows 
identifies the most relevant statutory sections and briefly explains 
the contours of the methodology used to implement these statutory 
requirements. A more comprehensive discussion appears in the document 
titled CAA Section 112 Risk and Technology Reviews: Statutory Authority 
and Methodology in the docket for this rulemaking.
    In the first stage of the CAA section 112 standard setting process, 
the EPA promulgates technology-based standards under CAA section 112(d) 
for categories of sources identified as emitting one or more of the HAP 
listed in CAA section 112(b). Sources of HAP emissions are either major 
sources or area sources, and CAA section 112 establishes different 
requirements for major source standards and area source standards. 
``Major sources'' are those that emit or have the potential to emit 10 
tons per year (tpy) or more of a single HAP or 25 tpy or more of any 
combination of HAP. All other sources are ``area sources.'' For major 
sources, CAA section 112(d)(2) provides that the technology-based 
NESHAP must reflect the maximum degree of emission reductions of HAP 
achievable (after considering cost, energy requirements, and non-air 
quality health and environmental impacts). These standards are commonly 
referred to as MACT standards. CAA section 112(d)(3) also establishes a 
minimum control level for MACT standards, known as the MACT ``floor.'' 
The EPA must also consider control options that are more stringent than 
the floor. Standards more stringent than the floor are commonly 
referred to as beyond-the-floor standards. In certain instances, as 
provided in CAA section 112(h), the EPA may set work practice standards 
where it is not feasible to prescribe or enforce a numerical emission 
standard. For area sources, CAA section 112(d)(5) gives the EPA 
discretion to set standards based on generally available control 
technologies or management practices (GACT standards) in lieu of MACT 
standards.
    The second stage in standard-setting focuses on identifying and 
addressing any remaining (i.e., ``residual'') risk according to CAA 
section 112(f). For source categories subject to MACT standards, 
section 112(f)(2) of the CAA requires the EPA to determine whether 
promulgation of additional standards is needed to provide an ample 
margin of safety to protect public health or to prevent an adverse 
environmental effect. Section 112(d)(5) of the CAA provides that this 
residual risk review is not required for categories of area sources 
subject to GACT standards. Section 112(f)(2)(B) of the CAA further 
expressly preserves the EPA's use of the two-step approach for 
developing standards to address any residual risk and the Agency's 
interpretation of ``ample margin of safety'' developed in the National 
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions 
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene 
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 
Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA 
notified Congress in the 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

[[Page 1573]]

Court of Appeals for the District of Columbia Circuit (the Court) 
upheld the EPA's interpretation that CAA section 112(f)(2) incorporates 
the approach established in the Benzene NESHAP. See NRDC v. EPA, 529 
F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach incorporated into the CAA and used by the EPA to 
evaluate residual risk and to develop standards under CAA section 
112(f)(2) is a two-step approach. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\1\ of approximately 1 in 10 thousand.'' 54 FR 38045, September 14, 
1989. If risks are unacceptable, the EPA must determine the emissions 
standards necessary to reduce risk to an acceptable level without 
considering costs. In the second step of the approach, the EPA 
considers whether the emissions standards provide an ample margin of 
safety to protect public health ``in consideration of all health 
information, including the number of persons at risk levels higher than 
approximately 1 in 1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate emission standards necessary to provide an ample margin of 
safety to protect public health. After conducting the ample margin of 
safety analysis, we consider whether a more stringent standard is 
necessary to prevent, taking into consideration costs, energy, safety, 
and other relevant factors, an adverse environmental effect.
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    \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.
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    CAA section 112(d)(6) separately requires the EPA to review 
standards promulgated under CAA section 112 and revise them ``as 
necessary (taking into account developments in practices, processes, 
and control technologies)'' no less often than every 8 years. In 
conducting this review, which we call the ``technology review,'' the 
EPA is not required to recalculate the MACT floor. Natural Resources 
Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008). 
Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 
2013). The EPA may consider cost in deciding whether to revise the 
standards pursuant to CAA section 112(d)(6).

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

    As described in section I.A of this preamble, the HCl Production 
source category includes facilities that are engaged in the production 
of HCl. In the initial list of source categories, Fume Silica 
Production was listed as a distinct source category. While developing 
the NESHAP for HCl Production, the EPA determined that HAP emissions 
from fume silica production were attributable to HCl production at 
these facilities. Therefore, during the proposal and promulgation of 
the NESHAP for HCl Production, the Fume Silica Production source 
category was subsumed into the HCl Production source category and the 
resulting HCl Production source category now includes HCl production at 
fume silica production facilities as well as other facilities producing 
HCl that were previously included in the source category.
    The HCl Production NESHAP covers sources located at major sources 
of HAP emissions. HCl production facilities are typically co-located at 
plant sites that include various other chemical manufacturing processes 
such as pesticide or organic chemical manufacturing. The HCl production 
facility is the basic unit defined in the NESHAP. Specifically, the 
rule defines an HCl production facility as the collection of unit 
operations and equipment associated with the production of liquid HCl 
product of 30 weight percent or greater. The production of liquid HCl 
product occurs through the absorption of gaseous HCl into either water 
or an aqueous HCl solution. The HCl production facility includes HCl 
storage tanks (as defined in 40 CFR 63.9075), HCl transfer operations 
that load the HCl product into a tank truck, rail car, ship, or barge, 
and equipment leaks. A plant site could have several separate and 
distinct HCl production facilities. The affected source includes all 
HCl production facilities at the same site.
    An HCl production facility begins at the point where a gaseous 
stream containing HCl \2\ enters an absorber and ends at the point 
where the liquid HCl product is loaded into a tank truck, rail car, 
ship, or barge, at the point the HCl product enters another process on 
the plant site, or at the point the HCl product leaves the plant site 
via pipeline. The gaseous stream leaving the absorption column contains 
HCl that was not absorbed into the liquid in the tower and any 
Cl<INF>2</INF> present in the inlet stream. If the outlet stream is 
directly discharged to the atmosphere or if it is routed through other 
control devices before being discharged to the atmosphere, it is 
considered an HCl process vent from an HCl production facility. If the 
outlet stream is routed (or recycled) to another process, it is not 
regulated under the HCl Production NESHAP, but could be regulated under 
a separate NESHAP related to the process to which it is routed. For 
example, if an HCl process vent emission stream is routed to a 
hazardous waste combustor regulated under 40 CFR part 63, subpart EEE, 
as supplemental combustion air, that process vent stream is subject to 
40 CFR part 63, subpart EEE rather than the HCl Production NESHAP.
---------------------------------------------------------------------------

    \2\ For purposes of the HCl Production NESHAP, how the gaseous 
HCl is produced does not affect applicability of the rule to the 
source. The source category only addresses the production of liquid 
HCl.
---------------------------------------------------------------------------

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

    The EPA used a variety of resources to obtain data about facilities 
and their emissions for use in our risk assessment. We used the EPA's 
Enforcement and Compliance History Online (ECHO) database to develop a 
list of potentially subject facilities. Using this list, we searched 
state environmental agency websites and correspondence with industry to 
obtain copies of title V permits to confirm whether facilities have HCl 
production subject to the NESHAP. Once the facility list was finalized, 
the EPA used the 2014 National Emissions Inventory (NEI) to get 
emissions data for each facility. We compared the NEI data to title V 
permits to provide additional information regarding the applicability 
of the HCl Production NESHAP. There were some instances in which 
sources listed in title V permits did not include HAP emissions in the 
NEI. As discussed in the memorandum titled HCl RTR Modeling File Data 
Source Documentation, which is available in the docket for this action, 
these gaps were filled using average data from other emission points 
for which data were available. Further discussion of the methodology 
used to develop the emissions dataset for the risk assessment can be 
found in the memorandum titled HCl RTR Modeling File Data Source 
Documentation, which is available in the docket for this action. 
Industry representatives provided data corrections where facility 
ownership or emission point parameters from the NEI were incorrect.

[[Page 1574]]

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

    We used information from the Reasonably Available Control 
Technology (RACT), Best Available Control Technology (BACT), and Lowest 
Achievable Emission Rate (LAER) Clearinghouse (RBLC) database, reviewed 
title V permits for each HCl production facility, and reviewed 
regulatory actions related to emissions controls at similar sources 
that could be applicable to HCl production. We reviewed the RBLC to 
identify potential additional control technologies. No additional 
control technologies applicable to HCl production were found using the 
RBLC. Additional information related to the original promulgation and 
subsequent amendments of the NESHAP is available in Docket ID No. EPA-
HQ-OAR-2002-0057.

III. Analytical Procedures and Decision-Making

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

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

    As discussed in section II.A of this preamble and in the Benzene 
NESHAP, in evaluating and developing standards under CAA section 
112(f)(2), we apply a two-step approach to determine whether or not 
risks are acceptable and to determine if the standards provide an ample 
margin of safety to protect public health. As explained in the Benzene 
NESHAP, ``the first step judgment on acceptability cannot be reduced to 
any single factor'' and, thus, ``[t]he Administrator believes that the 
acceptability of risk under section 112 is best judged on the basis of 
a broad set of health risk measures and information.'' 54 FR 38046, 
September 14, 1989. Similarly, with regard to the ample margin of 
safety determination, ``the Agency again considers all of the health 
risk and other health information considered in the first step. Beyond 
that information, additional factors relating to the appropriate level 
of control will also be considered, including cost and economic impacts 
of controls, technological feasibility, uncertainties, and any other 
relevant factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. The EPA conducts a risk 
assessment that provides estimates of the MIR posed by the HAP 
emissions from each source in the source category, the hazard index 
(HI) for chronic exposures to HAP with the potential to cause noncancer 
health effects, and the hazard quotient (HQ) for acute exposures to HAP 
with the potential to cause noncancer health effects.\3\ The assessment 
also provides estimates of the distribution of cancer risk within the 
exposed populations, cancer incidence, and an evaluation of the 
potential for an adverse environmental effect. The scope of the EPA's 
risk analysis is consistent with the EPA's response to comments on our 
policy under the Benzene NESHAP where the EPA explained that:
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    \3\ 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 his expertise to 
assess available data. It also complies with the Congressional 
intent behind the CAA, which did not exclude the use of any 
particular measure of public health risk from the EPA's 
consideration with respect to CAA section 112 regulations, and 
thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in his judgment, believes are 
---------------------------------------------------------------------------
appropriate to determining what will `protect the public health'.

    See 54 FR 38057, September 14, 1989. Thus, the level of the MIR is 
only one factor to be weighed in determining acceptability of risk. The 
Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes 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 the HAP risk that may be associated with emissions 
from other facilities that do not include the source category under 
review, mobile source emissions, natural source emissions, persistent 
environmental pollution, or atmospheric transformation in the vicinity 
of the sources in the category.
    The EPA understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
noncancer risk, where pollutant-specific exposure health reference 
levels (e.g., reference concentrations (RfCs)) are based on the 
assumption that thresholds exist for adverse health effects. For 
example, the EPA recognizes that, although exposures attributable to 
emissions from a source category or facility alone may not indicate the 
potential for increased risk of adverse noncancer health effects in a 
population, the exposures resulting from emissions from the facility in 
combination with emissions from all of the other sources (e.g., other 
facilities) to which an individual is exposed may be sufficient to 
result in 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.'' \4\
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    \4\ Recommendations of the SAB RTR Panel are provided in their 
report, which is available at: http://yosemite.epa.gov/sab/
sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-
007-unsigned.pdf.
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    In response to the SAB recommendations, the EPA incorporates

[[Page 1575]]

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

B. How do we perform the technology review?

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

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

    In this section, we provide a complete description of the types of 
analyses that we generally perform during the risk assessment process. 
In some cases, we do not perform a specific analysis because it is not 
relevant. For example, in the absence of emissions of HAP known to be 
persistent and bioaccumulative in the environment (PB-HAP), we would 
not perform a multipathway exposure assessment. Where we do not perform 
an analysis, we state that we do not and provide the reason. While we 
present all of our risk assessment methods, we only present risk 
assessment results for the analyses actually conducted (see section 
IV.B of this preamble).
    The EPA conducts a risk assessment that provides estimates of the 
MIR for cancer posed by the HAP emissions from each source in the 
source category, the HI for chronic exposures to HAP with the potential 
to cause noncancer health effects, and the HQ for acute exposures to 
HAP with the potential to cause noncancer health effects. The 
assessment also provides estimates of the distribution of cancer risk 
within the exposed populations, cancer incidence, and an evaluation of 
the potential for an adverse environmental effect. The seven sections 
that follow this paragraph describe how we estimated emissions and 
conducted the risk assessment. The docket for this rulemaking contains 
the following document which provides more information on the risk 
assessment inputs and models: Residual Risk Assessment for the 
Hydrochloric Acid Production Source Category in Support of the 2018 
Risk and Technology Review Proposed Rule. The methods used to assess 
risk (as described in the seven primary steps below) are consistent 
with those described by the EPA in the document reviewed by a panel of 
the EPA's SAB in 2009,\5\ and described in the SAB review report issued 
in 2010. They are also consistent with the key recommendations 
contained in that report.
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    \5\ U.S. EPA. Risk and Technology Review (RTR) Risk Assessment 
Methodologies: For Review by the EPA's Science Advisory Board with 
Case Studies--MACT I Petroleum Refining Sources and Portland Cement 
Manufacturing, June 2009. EPA-452/R-09-006. https://www3.epa.gov/airtoxics/rrisk/rtrpg.html.
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1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    As discussed in the memorandum titled, HCl RTR Modeling File Data 
Source Documentation, emissions data for sources subject to the HCl 
Production NESHAP were gathered primarily from the 2014 NEI. We 
compared the NEI data for each facility to title V permits to determine 
which emission points listed in the NEI are subject to the HCl 
Production NESHAP and made corrections when data were missing from the 
NEI or appeared to be incorrect. For example, if the flow rate for an 
emission point was missing, we calculated this release characteristic 
using the stack velocity and cross-sectional area of the stack. Each 
correction we made is discussed in the memorandum and supporting 
documents, available in the docket for this action. Industry provided a 
few corrections of facility ownership and emission point parameters, 
which are also available in the docket for this action.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during a specified annual 
timeperiod. These ``actual'' emission levels are often lower than the 
emission levels allowed under the requirements of the current MACT 
standards. The emissions allowed under the MACT standards are referred 
to as the ``MACT-allowable'' emissions. We discussed the consideration 
of both MACT-allowable and actual emissions in the final Coke Oven 
Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the proposed 
and final Hazardous Organic NESHAP RTR (71 FR 34428, June 14, 2006, and 
71 FR 76609,

[[Page 1576]]

December 21, 2006, respectively). In those actions, we noted that 
assessing the risk at the MACT-allowable level is inherently reasonable 
since that risk reflects the maximum level facilities could emit and 
still comply with national emission standards. We also explained that 
it is reasonable to consider actual emissions, where such data are 
available, in both steps of the risk analysis, in accordance with the 
Benzene NESHAP approach (54 FR 38044, September 14, 1989).
    We were unable to use the NEI data to calculate allowable emissions 
based on the concentration-based standard. We attempted to calculate 
allowable emission rates using the flow rates in the NEI and the 
concentration based standards for HCl and Cl<INF>2</INF>. For a number 
of sources, the calculated allowable emission values were substantially 
lower than actual emissions. This discrepancy could be due to incorrect 
flow rates in the NEI, conservatively high estimates of actual 
emissions, or actual emission estimates including HCl and 
Cl<INF>2</INF> emissions from sources not subject to the HCl NESHAP. We 
determined these estimates of allowable emission rates would not be 
appropriate. Instead, we estimated allowable emission rates by applying 
a factor of ten to actual emissions for process vents, material storage 
and loading, and storage tanks. Based on our engineering judgement, 
this factor of ten provides a very conservative estimate of allowable 
emission rates. Indeed, correspondence with industry suggests the 
allowable emission rates estimated using this method may be higher than 
facility-wide permitted emission rates for some facilities. Facilities 
typically operate below the level of the standard to provide a buffer 
between actual emission levels and the level of the standard. While we 
were not able to calculate the exact magnitude of this buffer for this 
source category, we believe that using a multiplier of 10 ensures we 
are not underestimating allowable emission rates. For more detail about 
the MACT-allowable emission levels, see the memorandum, HCl RTR 
Modeling File Data Source Documentation, which is available in the 
docket for this action. The standard for equipment leaks requires 
facilities to operate a leak detection and repair (LDAR) program. 
Consistent with other source categories with LDAR standards, we 
estimated that allowable emissions for equipment leaks are equal to 
actual emissions, since both actual and allowable emissions reflect the 
use of an LDAR program. Our estimates of actual and allowable emissions 
are further discussed in the memorandum titled HCl RTR Modeling File 
Data Source Documentation.
3. How do we conduct dispersion modeling, determine inhalation 
exposures, and estimate individual and population inhalation risk?
    Both long-term and short-term inhalation exposure concentrations 
and health risk from the source category addressed in this proposal 
were estimated using the Human Exposure Model (HEM-3).\6\ The HEM-3 
performs three primary risk assessment activities: (1) Conducting 
dispersion modeling to estimate the concentrations of HAP in ambient 
air, (2) estimating long-term and short-term inhalation exposures to 
individuals residing within 50 kilometers (km) of the modeled sources, 
and (3) estimating individual and population-level inhalation risk 
using the exposure estimates and quantitative dose-response 
information.
---------------------------------------------------------------------------

    \6\ For more information about HEM-3, go to https://www.epa.gov/fera/risk-assessment-and-modeling-human-exposure-model-hem.
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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.\7\ 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 \8\ 
internal point locations and populations provides the basis of human 
exposure calculations (U.S. Census, 2010). In addition, for each census 
block, the census library includes the elevation and controlling hill 
height, which are also used in dispersion calculations. A third library 
of pollutant-specific dose-response values is used to estimate health 
risk. These are discussed below.
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    \7\ 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).
    \8\ A census block is the smallest geographic area for which 
census statistics are tabulated.
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b. Risk From Chronic Exposure to HAP
    In developing the risk assessment for chronic exposures, we use the 
estimated annual average ambient air concentrations of each HAP emitted 
by each source in the source category. The HAP air concentrations at 
each nearby census block centroid located within 50 km of the facility 
are a surrogate for the chronic inhalation exposure concentration for 
all the people who reside in that census block. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044, September 14, 1989) and the limitations of Gaussian 
dispersion models, including AERMOD.
    For each facility, we calculate the MIR as the cancer risk 
associated with a continuous lifetime (24 hours per day, 7 days per 
week, 52 weeks per year, 70 years) exposure to the maximum 
concentration at the centroid of each inhabited census block. We 
calculate individual cancer risk by multiplying the estimated lifetime 
exposure to the ambient concentration of each HAP (in micrograms per 
cubic meter ([mu]g/m\3\)) by its unit risk estimate (URE). The URE is 
an upper-bound estimate of an individual's incremental risk of 
contracting cancer over a lifetime of exposure to a concentration of 1 
microgram of the pollutant per cubic meter of air. For residual risk 
assessments, we generally use UREs from the EPA's Integrated Risk 
Information System (IRIS). For carcinogenic pollutants without IRIS 
values, we look to other reputable sources of cancer dose-response 
values, often using California EPA (CalEPA) UREs, where available. In 
cases where new, scientifically credible dose-response values have been 
developed in a manner consistent with EPA guidelines and have undergone 
a peer review process similar to that used by the EPA, we may use such 
dose-response values in place of, or in addition to, other values, if 
appropriate. The pollutant-specific dose-response values used to 
estimate health risk are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
    To estimate individual lifetime cancer risks associated with 
exposure to HAP emissions from each facility in the source category, we 
sum the risks for each of the carcinogenic HAP \9\ emitted

[[Page 1577]]

by the modeled facility. We estimate cancer risk at every census block 
within 50 km of every facility in the source category. The MIR is the 
highest individual lifetime cancer risk estimated for any of those 
census blocks. In addition to calculating the MIR, we estimate the 
distribution of individual cancer risks for the source category by 
summing the number of individuals within 50 km of the sources whose 
estimated risk falls within a specified risk range. We also estimate 
annual cancer incidence by multiplying the estimated lifetime cancer 
risk at each census block by the number of people residing in that 
block, summing results for all of the census blocks, then dividing this 
result by a 70-year lifetime.
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    \9\ The EPA's 2005 Guidelines for Carcinogen Risk Assessment 
classifies carcinogens as: ``carcinogenic to humans,'' ``likely to 
be carcinogenic to humans,'' and ``suggestive evidence of 
carcinogenic potential.'' These classifications also coincide with 
the terms ``known carcinogen, probable carcinogen, and possible 
carcinogen,'' respectively, which are the terms advocated in the 
EPA's Guidelines for Carcinogen Risk Assessment, published in 1986 
(51 FR 33992, September 24, 1986). In August 2000, the document, 
Supplemental Guidance for Conducting Health Risk Assessment of 
Chemical Mixtures (EPA/630/R-00/002), was published as a supplement 
to the 1986 document. Copies of both documents can be obtained from 
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing 
the risk of these individual compounds to obtain the cumulative 
cancer risk is an approach that was recommended by the EPA's SAB in 
their 2002 peer review of the EPA's National Air Toxics Assessment 
(NATA) titled NATA--Evaluating the National-scale Air Toxics 
Assessment 1996 Data--an SAB Advisory, available at http://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
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    To assess the risk of noncancer health effects from chronic 
exposure to HAP, we calculate either an HQ or a target organ-specific 
hazard index (TOSHI). We calculate an HQ when a single noncancer HAP is 
emitted. Where more than one noncancer HAP is emitted, we sum the HQ 
for each of the HAP that affects a common target organ or target organ 
system to obtain a TOSHI. The HQ is the estimated exposure divided by 
the chronic noncancer dose-response value, which is a value selected 
from one of several sources. The preferred chronic noncancer dose-
response value is the EPA RfC defined as ``an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure to the human population (including sensitive 
subgroups) that is likely to be without an appreciable risk of 
deleterious effects during a lifetime'' (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary). In cases where an RfC 
from the EPA's IRIS is not available or where the EPA determines that 
using a value other than the RfC is appropriate, the chronic noncancer 
dose-response value can be a value from the following prioritized 
sources, which define their dose-response values similarly to the EPA: 
(1) The Agency for Toxic Substances and Disease Registry (ATSDR) 
Minimum Risk Level (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 EPA guidelines and has undergone a peer review process 
similar to that used by the EPA. The pollutant-specific dose-response 
values used to estimate health risks are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
c. Risk From Acute Exposure to HAP That May Cause Health Effects Other 
Than Cancer
    For each HAP for which appropriate acute inhalation dose-response 
values are available, the EPA also assesses the potential health risks 
due to acute exposure. For these assessments, the EPA makes 
conservative assumptions about emission rates, meteorology, and 
exposure location. We use the peak hourly emission rate,\10\ 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.
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    \10\ In the absence of hourly emission data, we develop 
estimates of maximum hourly emission rates by multiplying the 
average actual annual emissions rates by a factor (either a 
category-specific factor or a default factor of 10) to account for 
variability. This is documented in Residual Risk Assessment 
Hydrochloric Acid Production Source Category in Support of the 2018 
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.
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    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.'' \11\ Acute RELs are based on the most sensitive, 
relevant, adverse health effect reported in the peer-reviewed medical 
and toxicological literature. They are designed to protect the most 
sensitive individuals in the population through the inclusion of 
margins of safety. Because margins of safety are incorporated to 
address data gaps and uncertainties, exceeding the REL does not 
automatically indicate an adverse health impact. AEGLs represent 
threshold exposure limits for the general public and are applicable to 
emergency exposures ranging from 10 minutes to 8 hours.\12\ They are 
guideline levels for ``once-in-a-lifetime, short-term exposures to 
airborne concentrations of acutely toxic, high-priority chemicals.'' 
Id. at 21. The AEGL-1 is specifically defined as ``the airborne 
concentration (expressed as ppm (parts per million) or mg/m\3\ 
(milligrams per cubic meter)) of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic nonsensory effects. However, the effects are not 
disabling and are transient and reversible upon cessation of 
exposure.'' The document also notes that ``Airborne concentrations 
below AEGL-1 represent exposure levels that can produce mild and 
progressively increasing but transient and nondisabling odor, taste, 
and sensory irritation or certain asymptomatic, nonsensory effects.'' 
Id. AEGL-2 are defined as ``the airborne concentration (expressed as 
parts per million or milligrams per cubic meter) of a substance above 
which it is predicted that the general population, including 
susceptible individuals, could experience irreversible or other 
serious, long-lasting adverse health effects or an impaired ability to 
escape.'' Id.
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    \11\ CalEPA issues acute RELs as part of its Air Toxics Hot 
Spots Program, and the 1-hour and 8-hour values are documented in 
Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The 
Determination of Acute Reference Exposure Levels for Airborne 
Toxicants, which is available at http://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
    \12\ National Academy of Sciences, 2001. Standing Operating 
Procedures for Developing Acute Exposure Levels for Hazardous 
Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.pdf. Note that the 
National Advisory Committee for Acute Exposure Guideline Levels for 
Hazardous Substances ended in October 2011, but the AEGL program 
continues to operate at the EPA and works with the National 
Academies to publish final AEGLs (https://www.epa.gov/aegl).
---------------------------------------------------------------------------

    ERPGs are ``developed for emergency planning and are intended as 
health-based guideline concentrations for

[[Page 1578]]

single exposures to chemicals.'' \13\ Id. at 1. The ERPG-1 is defined 
as ``the maximum airborne concentration below which it is believed that 
nearly all individuals could be exposed for up to 1 hour without 
experiencing other than mild transient adverse health effects or 
without perceiving a clearly defined, objectionable odor.'' Id. at 2. 
Similarly, the ERPG-2 is defined as ``the maximum airborne 
concentration below which it is believed that nearly all individuals 
could be exposed for up to one hour without experiencing or developing 
irreversible or other serious health effects or symptoms which could 
impair an individual's ability to take protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \13\ ERPGS Procedures and Responsibilities, March 2014. American 
Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf.
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    An acute REL for 1-hour exposure durations is typically lower than 
its corresponding AEGL-1 and ERPG-1. Even though their definitions are 
slightly different, AEGL-1s are often the same as the corresponding 
ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from 
our acute inhalation screening risk assessment typically result when we 
use the acute REL for a HAP. In cases where the maximum acute HQ 
exceeds 1, we also report the HQ based on the next highest acute dose-
response value (usually the AEGL-1 and/or the ERPG-1).
    For this source category, we used the default factor of 10 for the 
acute inhalation screening and refined screening assessment. In our 
acute inhalation screening risk assessment, acute impacts are deemed 
negligible for HAP for which acute HQs are less than or equal to 1 
(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 exposures of concern. For this source category, the 
data refinements consisted of determining the highest HQ value that 
occurs outside facility boundaries. These refinements are discussed 
more fully in the Residual Risk Assessment for the Hydrochloric Acid 
Production Source Category in Support of the Risk and Technology Review 
2018 Proposed Rule, which is available in the docket for this source 
category.
4. How do we conduct the multipathway exposure and risk screening 
assessment?
    The EPA conducts a tiered screening assessment examining the 
potential for significant human health risks due to exposures via 
routes other than inhalation (i.e., ingestion). We first determine 
whether any sources in the source category emit any 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 HCl Production 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 do we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect, Environmental HAP, and Ecological 
Benchmarks
    The EPA conducts a screening assessment to examine the potential 
for an adverse environmental effect as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
    The EPA focuses on eight HAP, which are referred to as 
``environmental HAP,'' in its screening assessment: Six PB-HAP and two 
acid gases. The PB-HAP included in the screening assessment are arsenic 
compounds, cadmium compounds, dioxins/furans, polycyclic organic matter 
(POM), mercury (both inorganic mercury and methyl mercury), and lead 
compounds. The acid gases included in the screening assessment are HCl 
and hydrogen fluoride (HF).
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment, and water. The 
acid gases, HCl and HF, are included due to their well-documented 
potential to cause direct damage to terrestrial plants. In the 
environmental risk screening assessment, we evaluate the following four 
exposure media: Terrestrial soils, surface water bodies (includes 
water-column and benthic sediments), fish consumed by wildlife, and 
air. Within these four exposure media, we evaluate nine ecological 
assessment endpoints, which are defined by the ecological entity and 
its attributes. For PB-HAP (other than lead), both community-level and 
population-level endpoints are included. For acid gases, the ecological 
assessment evaluated is terrestrial plant communities.
    An ecological benchmark represents a concentration of HAP that has 
been linked to a particular environmental effect level. For each 
environmental HAP, we identified the available ecological benchmarks 
for each assessment endpoint. We identified, where possible, ecological 
benchmarks at the following effect levels: Probable effect levels, 
lowest-observed-adverse-effect level, and no-observed-adverse-effect 
level. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we use all of the available 
effect levels to help us to determine whether ecological risks exist 
and, if so, whether the risks could be considered significant and 
widespread.
    For further information on how the environmental risk screening 
assessment was conducted, including a discussion of the risk metrics 
used, how the environmental HAP were identified, and how the ecological 
benchmarks were selected, see Appendix 9 of the Residual Risk 
Assessment for the Hydrochloric Acid Production Source Category in 
Support of the Risk and Technology Review 2018 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 HCl Production source category 
emitted any of the environmental HAP. For the HCl Production source 
category, we identified emissions of HCl. Because one or more of the 
environmental HAP evaluated (HCl) is emitted by at least one facility 
in the source category, we proceeded to the second step of the 
evaluation.
c. PB-HAP Methodology
    The environmental screening assessment includes six PB-HAP, arsenic 
compounds, cadmium compounds, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), and lead compounds. With the 
exception of lead, the environmental risk screening assessment for PB-
HAP consists of three tiers. The first tier of the environmental

[[Page 1579]]

risk screening assessment uses the same health-protective conceptual 
model that is used for the Tier 1 human health screening assessment. 
TRIM.FaTE model simulations were used to back-calculate Tier 1 
screening threshold emission rates. The screening threshold emission 
rates represent the emission rate in tpy that results in media 
concentrations at the facility that equal the relevant ecological 
benchmark. To assess emissions from each facility in the category, the 
reported emission rate for each PB-HAP was compared to the Tier 1 
screening threshold emission rate for that PB-HAP for each assessment 
endpoint and effect level. If emissions from a facility do not exceed 
the Tier 1 screening threshold emission rate, the facility ``passes'' 
the screening assessment, and, therefore, is not evaluated further 
under the screening approach. If emissions from a facility exceed the 
Tier 1 screening threshold emission rate, we evaluate the facility 
further in Tier 2.
    In Tier 2 of the environmental screening assessment, the screening 
threshold emission rates are adjusted to account for local meteorology 
and the actual location of lakes in the vicinity of facilities that did 
not pass the Tier 1 screening assessment. For soils, we evaluate the 
average soil concentration for all soil parcels within a 7.5-km radius 
for each facility and PB-HAP. For the water, sediment, and fish tissue 
concentrations, the highest value for each facility for each pollutant 
is used. If emission concentrations from a facility do not exceed the 
Tier 2 screening threshold emission rate, the facility ``passes'' the 
screening assessment and typically is not evaluated further. If 
emissions from a facility exceed the Tier 2 screening threshold 
emission rate, we evaluate the facility further in Tier 3.
    Like in the multipathway human health risk assessment, in Tier 3 of 
the environmental screening assessment, we examine the suitability of 
the lakes around the facilities to support life and remove those that 
are not suitable (e.g., lakes that have been filled in or are 
industrial ponds), adjust emissions for plume-rise, and conduct hour-
by-hour time-series assessments. If these Tier 3 adjustments to the 
screening threshold emission rates still indicate the potential for an 
adverse environmental effect (i.e., facility emission rate exceeds the 
screening threshold emission rate), we may elect to conduct a more 
refined assessment using more site-specific information. If, after 
additional refinement, the facility emission rate still exceeds the 
screening threshold emission rate, the facility may have the potential 
to cause an adverse environmental effect.
    To evaluate the potential for an adverse environmental effect from 
lead, we compared the average modeled air concentrations (from HEM-3) 
of lead around each facility in the source category to the level of the 
secondary National Ambient Air Quality Standards (NAAQS) for lead. The 
secondary lead NAAQS is a reasonable means of evaluating environmental 
risk because it is set to provide substantial protection against 
adverse welfare effects which can include ``effects on soils, water, 
crops, vegetation, man-made materials, animals, wildlife, weather, 
visibility and climate, damage to and deterioration of property, and 
hazards to transportation, as well as effects on economic values and on 
personal comfort and well-being.''
d. Acid Gas Environmental Risk Methodology
    The environmental screening assessment for acid gases evaluates the 
potential phytotoxicity and reduced productivity of plants due to 
chronic exposure to HF and HCl. The environmental risk screening 
methodology for acid gases is a single-tier screening assessment that 
compares modeled ambient air concentrations (from AERMOD) to the 
ecological benchmarks for each acid gas. To identify a potential 
adverse environmental effect (as defined in section 112(a)(7) of the 
CAA) from emissions of HF and HCl, we evaluate the following metrics: 
The size of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas, in acres and km\2\; the 
percentage of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas; and the area-weighted average 
screening value around each facility (calculated by dividing the area-
weighted average concentration over the 50-km modeling domain by the 
ecological benchmark for each acid gas). For further information on the 
environmental screening assessment approach, see Appendix 9 of the 
Residual Risk Assessment for the Hydrochloric Acid Production Source 
Category in Support of the Risk and Technology Review 2018 Proposed 
Rule, which is available in the docket for this action.
6. How do we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category emission points of interest, but also emissions of HAP 
from all other emission sources at the facility for which we have data. 
For this source category, we conducted the facility-wide assessment 
using a dataset compiled from the 2014 NEI. The source category records 
of that NEI dataset were removed, evaluated, and updated as described 
in section II.C of this preamble: What data collection activities were 
conducted to support this action? Once a quality assured source 
category dataset was available, it was placed back with the remaining 
records from the NEI for that facility. The facility-wide file was then 
used to analyze risks due to the inhalation of HAP that are emitted 
``facility-wide'' for the populations residing within 50 km of each 
facility, consistent with the methods used for the source category 
analysis described above. For these facility-wide risk analyses, the 
modeled source category risks were compared to the facility-wide risks 
to determine the portion of the facility-wide risks that could be 
attributed to the source category addressed in this proposal. We also 
specifically examined the facility that was associated with the highest 
estimate of risk and determined the percentage of that risk 
attributable to the source category of interest. The Residual Risk 
Assessment for the Hydrochloric Acid Production Source Category in 
Support of the Risk and Technology Review 2018 Proposed Rule, available 
through the docket for this action, provides the methodology and 
results of the facility-wide analyses, including all facility-wide 
risks and the percentage of source category contribution to facility-
wide risks.
    For this source category, we conducted the facility-wide assessment 
using a dataset that the EPA compiled from the 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

[[Page 1580]]

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 Hydrochloric Acid 
Production Source Category in Support of the Risk and Technology Review 
2018 Proposed Rule, available through the docket for this action, 
provides the methodology and results of the facility-wide analyses, 
including all facility-wide risks and the percentage of source category 
contribution to facility-wide risks.
7. How do we consider uncertainties in risk assessment?
    Uncertainty and the potential for bias are inherent in all risk 
assessments, including those performed for this proposal. Although 
uncertainty exists, we believe that our approach, which used 
conservative tools and assumptions, ensures that our decisions are 
health and environmentally protective. A brief discussion of the 
uncertainties in the RTR emissions dataset, dispersion modeling, 
inhalation exposure estimates, and dose-response relationships follows 
below. Also included are those uncertainties specific to our acute 
screening assessments, multipathway screening assessments, and our 
environmental risk screening assessments. A more thorough discussion of 
these uncertainties is included in the Residual Risk Assessment for the 
Hydrochloric Acid Production Source Category in Support of the Risk and 
Technology Review 2018 Proposed Rule, which is available in the docket 
for this action. If a multipathway site-specific assessment was 
performed for this source category, a full discussion of the 
uncertainties associated with that assessment can be found in Appendix 
11 of that document, Site-Specific Human Health Multipathway Residual 
Risk Assessment Report.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates, and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years, and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to estimate 
ambient pollutant concentrations, the user chooses certain options to 
apply. For RTR assessments, we select some model options that have the 
potential to overestimate ambient air concentrations (e.g., not 
including plume depletion or pollutant transformation). We select other 
model options that have the potential to underestimate ambient impacts 
(e.g., not including building downwash). Other options that we select 
have the potential to either under or overestimate ambient levels 
(e.g., meteorology and receptor locations). On balance, considering the 
directional nature of the uncertainties commonly present in ambient 
concentrations estimated by dispersion models, the approach we apply in 
the RTR assessments should yield unbiased estimates of ambient HAP 
concentrations. We also note that the selection of meteorology dataset 
location could have an impact on the risk estimates. As we continue to 
update and expand our library of meteorological station data used in 
our risk assessments, we expect to reduce this variability.
c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant 
facilities and emission points, as well as to develop accurate 
estimates of the annual emission rates for all relevant HAP, the 
uncertainties in our emission inventory likely dominate the 
uncertainties in the exposure assessment. Some uncertainties in our 
exposure assessment include human mobility, using the centroid of each 
census block, assuming lifetime exposure, and assuming only outdoor 
exposures. For most of these factors, there is neither an under nor 
overestimate when looking at the maximum individual risk or the 
incidence, but the shape of the distribution of risks may be affected. 
With respect to outdoor exposures, actual exposures may not be as high 
if people spend time indoors, especially for very reactive pollutants 
or larger particles. For all factors, we reduce uncertainty when 
possible. For example, with respect to census-block centroids, we 
analyze large blocks using aerial imagery and adjust locations of the 
block centroids to better represent the population in the blocks. We 
also add additional receptor locations where the population of a block 
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and noncancer effects from both chronic and acute 
exposures. Some uncertainties are generally expressed quantitatively, 
and others are generally expressed in qualitative terms. We note, as a 
preface to this discussion, a point on dose-response uncertainty that 
is stated in the EPA's 2005 Guidelines for Carcinogen Risk Assessment; 
namely, that ``the primary goal of EPA actions is protection of human 
health; accordingly, as an Agency policy, risk assessment procedures, 
including default options that are used in the absence of scientific 
data to the contrary, should be health protective'' (EPA's 2005 
Guidelines for Carcinogen Risk Assessment, page 1-7). This is the 
approach followed here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been 
developed to generally provide an upper bound estimate of risk. 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).\14\ In some circumstances, the true risk could be as low as 
zero; however, in other circumstances the risk could be greater.\15\ 
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

[[Page 1581]]

derive dose-response values that are intended to protect against 
appreciable risk of deleterious effects.
---------------------------------------------------------------------------

    \14\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \15\ 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 we make every effort to identify appropriate human health 
effect dose-response values for all pollutants emitted by the sources 
in this risk assessment, some HAP emitted by this source category are 
lacking dose-response assessments. Accordingly, these pollutants cannot 
be included in the quantitative risk assessment, which could result in 
quantitative estimates understating HAP risk. To help to alleviate this 
potential underestimate, where we conclude similarity with a HAP for 
which a dose-response value is available, we use that value as a 
surrogate for the assessment of the HAP for which no value is 
available. To the extent use of surrogates indicates appreciable risk, 
we may identify a need to increase priority for an IRIS assessment for 
that substance. We additionally note that, generally speaking, HAP of 
greatest concern due to environmental exposures and hazard are those 
for which dose-response assessments have been performed, reducing the 
likelihood of understating risk. Further, HAP not included in the 
quantitative assessment are assessed qualitatively and considered in 
the risk characterization that informs the risk management decisions, 
including consideration of HAP reductions achieved by various control 
options.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective dose-response value 
of an individual compound in that group to estimate risk. Similarly, 
for an individual compound in a group (e.g., ethylene glycol diethyl 
ether) that does not have a specified dose-response value, we also 
apply the most protective dose-response value from the other compounds 
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA. The 
accuracy of an acute inhalation exposure assessment depends on the 
simultaneous occurrence of independent factors that may vary greatly, 
such as hourly 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, and, 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.
f. Uncertainties in the Multipathway and Environmental Risk Screening 
Assessments
    For each source category, we generally rely on site-specific levels 
of PB-HAP or environmental HAP emissions to determine whether a refined 
assessment of the impacts from multipathway exposures is necessary or 
whether it is necessary to perform an environmental screening 
assessment. This determination is based on the results of a three-
tiered screening assessment that relies on the outputs from models--
TRIM.FaTE and AERMOD--that estimate environmental pollutant 
concentrations and human exposures for five PB-HAP (dioxins, POM, 
mercury, cadmium, and arsenic) and two acid gases (HCl and hydrogen 
chloride). For lead, we use AERMOD to determine ambient air 
concentrations, which are then compared to the secondary NAAQS standard 
for lead. Two important types of uncertainty associated with the use of 
these models in RTR risk assessments and inherent to any assessment 
that relies on environmental modeling are model uncertainty and input 
uncertainty.\16\
---------------------------------------------------------------------------

    \16\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the model adequately represents 
the actual processes (e.g., movement and accumulation) that might occur 
in the environment. For example, does the model adequately describe the 
movement of a pollutant through the soil? This type of uncertainty is 
difficult to quantify. However, based on feedback received from 
previous EPA SAB reviews and other reviews, we are confident that the 
models used in the screening assessments are appropriate and state-of-
the-art for the multipathway and environmental screening risk 
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
1 of the multipathway and environmental screening assessments, we 
configured the models to avoid underestimating exposure and risk. This 
was accomplished by selecting upper-end values from nationally 
representative datasets for the more influential parameters in the 
environmental model, including selection and spatial configuration of 
the area of interest, lake location and size, meteorology, surface 
water, soil characteristics, and structure of the aquatic food web. We 
also assume an ingestion exposure scenario and values for human 
exposure factors that represent reasonable maximum exposures.
    In Tier 2 of the multipathway and environmental screening 
assessments,

[[Page 1582]]

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

IV. Analytical Results and Proposed Decisions

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

    As described above, for the HCl Production source category, we 
conducted an inhalation risk assessment and an environmental risk 
screening assessment on the only two HAP emitted, HCl and 
Cl<INF>2</INF>. No PB-HAP are emitted from this source category; 
therefore, a multipathway risk assessment was not warranted. We present 
results of the risk assessment briefly below and in more detail in the 
residual risk document titled Residual Risk Assessment for the 
Hydrochloric Acid Production Source Category in Support of the Risk and 
Technology Review 2018 Proposed Rule, which is available in the docket 
for this action.
1. Inhalation Risk Assessment Results
    Table 2 of this preamble provides an overall summary of the results 
of the inhalation risk assessment.

                                     Table 2--Inhalation Risk Assessment Summary for HCl Production Source Category
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Cancer MIR (in 1 million)                      Population      Population
                                           --------------------------------     Cancer        with cancer     with cancer
                                               Based on        Based on        incidence    risk of 1-in-1  risk of 10-in-    Max chronic noncancer HI
                                                actual         allowable      (cases per      million or     1 million or     actuals (and allowables)
                                               emissions       emissions         year)           more            more
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category...........................               0               0               0               0               0  0.2 (actuals)
                                                                                                                            2 (allowables)
Whole Facility............................             600  ..............            0.09         980,000         130,000  6
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The inhalation risk modeling performed to estimate risks based on 
actual emissions relied primarily on emissions data from the NEI. For 
allowable emissions, the NEI data was used to calculate conservative 
estimates of emissions. The results of the inhalation cancer risk 
assessment, as shown in Table 2 of this preamble, indicate there is no 
quantifiable cancer risk posed by the source category since the two HAP 
emitted from the HCl Production source category are not known or 
suspected carcinogens. Neither the EPA nor the International Agency for 
Research on Cancer (IARC) has evaluated the weight of evidence with 
respect to human carcinogenicity for Cl<INF>2</INF>. However, IARC has 
determined that hydrogen chloride is not classifiable as a human 
carcinogen. Likewise, the total estimated cancer incidence is 0 (zero) 
excess cancer cases per year and no people are estimated to have cancer 
risk associated with this source category. The maximum modeled chronic 
noncancer HI (TOSHI) value for the source category based on actual 
emissions is estimated to be 0.2, driven by emissions of Cl<INF>2</INF> 
from process vents. The target organ affected is the respiratory 
system. Exposure to HI levels will be less than 1 for populations in 
the vicinity of an HCl production facility as a result of emissions 
from this source category. The maximum chronic noncancer TOSHI would 
increase when based on allowable emissions, with a TOSHI as high as 2 
(respiratory) driven by Cl<INF>2</INF> emissions from process vents at 
two facilities. Based on allowable emissions, 300 people are estimated 
to

[[Page 1583]]

have a noncancer HI above 1 at these two facilities.
2. Acute Risk Results
    The screening and refined analyses for acute impacts was based on 
actual emissions, and to estimate the peak emission rates from the 
average rates, a default multiplier of 10 was used for emission points 
in the source category. The choice of a default multiplier of 10 is 
discussed in section III.C.3.c of this preamble. The results of the 
acute refined analysis indicate that the maximum off-facility-site 
acute HQ is 0.7, based on the REL value for HCl, and occurs at one 
facility. Refer to the document titled HCl RTR Modeling File Data 
Source Documentation (available in the docket for this action) for a 
detailed description of how the acute factors were developed for this 
source category. For more detailed acute risk results, refer to the 
residual risk document titled Residual Risk Assessment for the 
Hydrochloric Acid Production Source Category in Support of the Risk and 
Technology Review 2018 Proposed Rule, which is available in the docket 
for this action.
3. Multipathway Risk Screening Results
    No PB-HAP (cadmium, dioxins, POM, mercury, arsenic, and lead) are 
emitted from this source category. Therefore, a multi-pathway 
assessment is not warranted.
4. Environmental Risk Screening Results
    The only environmental HAP emitted by facilities in this source 
category is HCl. Results of the analysis for HCl indicate that, based 
on actual emissions, the maximum annual off-site concentration is below 
all ecological benchmarks for all facilities. Therefore, we do not 
expect an adverse environmental effect as a result of HAP emissions 
from this source category. For more detail on the environmental risk 
screening assessment, refer to the residual risk document titled 
Residual Risk Assessment for the Hydrochloric Acid Production Source 
Category in Support of the Risk and Technology Review 2018 Proposed 
Rule, which is available in the docket for this action.
5. Facility-Wide Risk Results
    We performed an assessment of the facility-wide risks to provide 
context for the source category risks, using NEI data as described 
above. The maximum facility-wide cancer MIR is 600-in-1 million, mainly 
driven by ethylene oxide emissions from a variety of industrial 
processes, none of which are part of this source category. The total 
estimated cancer incidence from the facility-wide assessment is 0.09 
excess cancer cases per year, or one excess case in every 11 years. We 
estimate that approximately 980,000 people have cancer risks greater 
than 1-in-1 million from exposure to HAP emitted from sources not 
subject to the HCl Production NESHAP. We estimate that the maximum 
facility-wide TOSHI is 6, mainly driven by emissions of 
trichloroethylene from chemical manufacturing processes that are not 
part of this source category. The target organs affected are kidney, 
immunological, developmental, neurological, reproductive, and liver. We 
estimate that approximately 760 people are exposed to noncancer HI 
levels above 1, based on facility-wide emissions (not subject to the 
HCl Production NESHAP) from the 19 facilities within this source 
category.
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 risk 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 risk from the HCl Production source 
category across different demographic groups within the populations 
living near facilities.\17\
---------------------------------------------------------------------------

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

    Results of the demographic analysis indicate that, for 3 of the 11 
demographic groups, minorities, African American, and below the poverty 
level, 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 HCl production 
facilities, we find that no one within 50 km (risk modeling domain) is 
exposed to a cancer risk because the two HAP emitted are not known 
carcinogens. Furthermore, no person is exposed to a noncancer TOSHI 
greater than 1 due to HAP emissions from the HCl Production source 
category.
    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 Hydrochloric Acid 
Production, available in the docket for this action.

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

1. Risk Acceptability
    As noted in section II.A of this preamble, the EPA sets standards 
under CAA section 112(f)(2) using ``a two-step standard-setting 
approach, with an analytical first step to determine an `acceptable 
risk' that considers all health information, including risk estimation 
uncertainty, and includes a presumptive limit on MIR of `approximately 
1-in-10 thousand.' '' See 54 FR 38045, September 14, 1989. We weigh all 
health risk factors in our risk acceptability determination, including 
the cancer MIR, cancer incidence, the maximum noncancer TOSHI, the 
maximum acute noncancer HQ, the extent of noncancer risk, the 
distribution of cancer and noncancer risk in the exposed population, 
and the risk estimation uncertainties.
    For this risk assessment, the EPA estimated risk based on actual 
and allowable emissions from HCl production sources. There are no 
quantifiable cancer risk or cancer incidence associated with this 
source category. Likewise, a TOSHI less than 1 indicates that the 
combined HAP affecting a particular target organ are not likely to 
cause adverse chronic noncancer health effects. Also, the acute refined 
assessment indicates little potential concern of acute noncancer health 
impacts. We identified no PB-HAP emitted from the source category, and, 
thus, no known potential for multi-pathway effects.
    Considering all of the health risk information and factors 
discussed above, including the uncertainties discussed in section III 
of this preamble, the EPA proposes that the risks from the HCl 
Production source category are acceptable.
2. Ample Margin of Safety Analysis
    As directed by CAA section 112(f)(2), we conducted an analysis to 
determine if the current emissions standards provide an ample margin of 
safety to protect public health. Under the ample margin of safety 
analysis, the EPA considers all health factors evaluated in the risk 
assessment and evaluates the cost and feasibility of available control 
technologies and other measures

[[Page 1584]]

(including the controls, measures, and costs reviewed under the 
technology review) that could be applied to this source category to 
further reduce the risks (or potential risks) due to emissions of HAP 
identified in our risk assessment. In this analysis, we considered the 
results of the technology review, risk assessment, and other aspects of 
our MACT rule review to determine whether there are any cost-effective 
controls or other measures that would reduce emissions further to 
provide an ample margin of safety with respect to the risks associated 
with these emissions.
    As provided in more detail in section IV.D below, we did not 
identify any developments in processes, practices, or controls for HCl 
production facilities during our analysis for this proposal. 
Hydrochloric acid production facilities use scrubbers to control 
emissions of HCl and Cl<INF>2</INF>. These devices are capable of 
achieving high levels of emission reductions and we did not identify 
additional technologies capable of further reducing emissions from HCl 
production facilities or any improvements to the existing technologies 
that would result in further reduction of emissions. Given that we did 
not identify any developments in practices, process, or control 
technologies and the low risks remaining after implementation of the 
NESHAP, we are proposing that the existing standards for the HCl 
Production source category provide an ample margin of safety.
    Regarding the facility-wide risks due to ethylene oxide and 
trichloroethylene (described above), which are due to emission sources 
that are not part of the HCl Production source category, we intend to 
evaluate those facility-wide estimated emissions and risks further and 
may address these in a separate future action, as appropriate. In 
particular, the EPA is addressing ethylene oxide based on the results 
of the latest NATA released in August 2018, which identified the 
chemical as a potential concern in several areas across the country. 
The latest NATA estimates that ethylene oxide significantly contributes 
to potential elevated cancer risks in some census tracts across the 
U.S. (less than 1 percent of the total number of tracts). As noted on 
the EPA's NATA website, NATA is a screening tool for state, local, and 
tribal air agencies and the EPA suggests that NATA results be used 
cautiously.\18\ These elevated risks are largely driven by an EPA risk 
value that was updated in late 2016. Although this updated risk value 
is also responsible for the elevated facility-wide risks calculated 
here, as noted earlier, these risks are due to emission sources that 
are not part of the HCl Production source category. Nevertheless, the 
EPA is interested in receiving public comments on the use of the update 
risk value for regulatory purposes.
---------------------------------------------------------------------------

    \18\ In particular, the EPA has identified limitations to 
consider when looking at the results (e.g., data gaps, default 
assumptions, and regional differences in emissions data 
completeness). A number of other aspects of the results are also 
worth noting, such as the results apply best to larger areas, not 
specific places; apply only to the analysis year (when the source 
data were collected); and assume a person breathes the air toxics 
emitted in the analysis every day for 70 years. See https://www.epa.gov/national-air-toxics-assessment/nata-limitations for a 
more complete discussion.
---------------------------------------------------------------------------

    The EPA will work with industry and state, local, and tribal air 
agencies as the EPA takes a two-pronged approach to address ethylene 
oxide emissions: (1) Reviewing CAA regulations for facilities that emit 
ethylene oxide--starting with air toxics emissions standards for 
miscellaneous organic chemical manufacturing facilities and commercial 
sterilizers; and (2) getting additional information on ethylene oxide 
emissions. This information will help the EPA as it evaluates 
opportunities to reduce ethylene oxide emissions as part of its 
regulations review, and will help the agency determine whether more 
immediate emission reduction steps are necessary in any particular 
locations. The EPA will post updates on its work to address ethylene 
oxide on its website at: https://www.epa.gov/ethylene-oxide.
3. Adverse Environmental Effect
    The emissions data for this source category indicate the presence 
of one environmental HAP, HCl, emitted by sources within this source 
category. Based on the results of our environmental risk screening 
assessment, we conclude that there is not an adverse environmental 
effect as a result of HAP emissions from the HCl Production source 
category. Thus, we are proposing that it is not necessary to set a more 
stringent standard to prevent an adverse environmental effect.

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

    We did not identify any developments in processes, practices, or 
controls for HCl production facilities during our analysis for this 
proposal. We are not proposing any changes to the NESHAP based on our 
technology review. Scrubbers are used across the industry to control 
emissions of HCl and Cl<INF>2</INF>, with similar performance among 
facilities. We reviewed the EPA's RACT/BACT/LAER Clearinghouse to 
identify possible developments and none were found. Additionally, we 
reviewed title V permits for all facilities and found no substantive 
differences in the control strategies employed for HCl production 
facilities. Finally, a search of peer reviewed literature did not yield 
any information regarding technology developments for HCl production.

D. What other actions are we proposing?

    In addition to the proposed determinations regarding the RTRs 
described above, we are proposing some revisions to the NESHAP to 
address other issues. 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 various changes 
to recordkeeping and reporting requirements and adding electronic 
reporting. Our analyses and proposed changes related to these issues 
are discussed below.
1. SSM 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.
    We are proposing the elimination of the SSM exemption in this rule 
which appears at 40 CFR 63.9005(a). Consistent with Sierra Club v. EPA, 
we are proposing standards in this rule that apply at all times. We are 
also proposing several revisions to Table 7 (the General Provisions 
Applicability Table) as explained in more detail below. For example, we 
are proposing to eliminate the incorporation of the General Provisions' 
requirement that the source develop an SSM plan. We also are proposing 
to eliminate and revise certain recordkeeping and reporting 
requirements related to the SSM exemption as further described below.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate,

[[Page 1585]]

unnecessary, or redundant in the absence of the SSM exemption. We are 
specifically seeking comment on whether we have successfully done so.
    In proposing the standards in this rule, the EPA has taken into 
account startup and shutdown periods. For the reasons explained below, 
the EPA is not proposing alternate standards for those periods, but is 
instead proposing that the source meet the otherwise applicable 
standards during these periods. We have no data indicating that 
emissions are different during startup or shutdown. For add-on control 
systems, the HCl Production NESHAP requires the measurement of scrubber 
flow rate and pH parameter limits apply at all times, including during 
periods of startup and shutdown. The HCl Production NESHAP requires 
add-on control device operating parameters to be recorded at least once 
every 15 minutes. The HCl Production NESHAP specifies in 40 CFR 
63.9040(c) that if an operating parameter is out of the allowed range, 
this is a deviation from the operating limit and must be reported as 
specified in 40 CFR 63.9050(d).
    The EPA is also proposing that the otherwise applicable limits 
would apply during periods of malfunction. 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 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 emissions standards 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 Risk and Technology Review, 
the EPA established a work practice standard for unique types of 
malfunction that result in releases from pressure relief devices or 
emergency flaring events because the EPA had information to determine 
that such work practices reflected the level of control that applies to 
the best performers. 80 FR 75178, 75211-14 (December 1, 2015). The EPA 
will consider whether circumstances warrant setting standards for a 
particular type of malfunction and, if so, whether the EPA has 
sufficient information to identify the relevant best performing sources 
and establish a standard for such malfunctions. We also encourage 
commenters to provide any such information.
    In the 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

[[Page 1586]]

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.
    The EPA is not aware of circumstances that would allow for 
establishing different emissions standard for some or all malfunctions 
that may occur at HCl production facilities and, therefore, is not 
proposing an alternative standard that would apply during periods of 
malfunction.
    In summary, the EPA's interpretation of the CAA and, in particular, 
CAA section 112, is reasonable and encourages practices that will avoid 
malfunctions. Administrative and judicial procedures for addressing 
exceedances of the standards fully recognize that violations may occur 
despite good faith efforts to comply and can accommodate those 
situations. U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
2. 40 CFR 63.9005 General Duty
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.6(e)(1)(i) by changing the ``yes'' in column 3 to a 
``no.'' Section 63.6(e)(1)(i) describes the general duty to minimize 
emissions during periods of SSM. With the elimination of the SSM 
exemption, there is no need to differentiate between normal operations, 
startup and shutdown, and malfunction events in describing the general 
duty. We are proposing instead to add general duty regulatory text at 
40 CFR 63.9005(b) that reflects the general duty to minimize emissions 
during all periods of operation. Therefore, the language the EPA is 
proposing for 40 CFR 63.9005(b) does not include that language from 40 
CFR 63.6(e)(1).
    We are also proposing to revise the General Provisions table (Table 
7) entry for 40 CFR 63.6(e)(1)(ii) by changing the ``yes'' in column 3 
to a ``no.'' This provision requires malfunctions to be corrected as 
quickly as practicable and minimize emissions consistent with safety 
and good air pollution control practices. Section 63.6(e)(1)(ii) 
imposes requirements that are not necessary with the elimination of the 
SSM exemption or are redundant with the general duty requirement being 
added at 40 CFR 63.9005(b).
3. SSM Plan
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.6(e)(3) by changing the ``yes'' in column 3 to a 
``no.'' Generally, these paragraphs require development of an SSM plan 
and specify SSM recordkeeping and reporting requirements related to the 
SSM plan. As noted, the EPA is proposing to remove the SSM exemptions. 
Therefore, affected units will be subject to an emission standard 
during such events. The applicability of a standard during such events 
will ensure that sources have ample incentive to plan for and achieve 
compliance as they do during periods of normal operation and, thus, 
planning requirements specific for SSM are no longer necessary.
4. Compliance With Standards
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.6(f)(1) by changing the ``yes'' in column 3 to a 
``no.'' The current language of 40 CFR 63.6(f)(1) exempts sources from 
non-opacity standards during periods of SSM. As discussed above, the 
Court in Sierra Club vacated the exemptions contained in 40 CFR 
63.6(f)(1) and held that the CAA requires a standard to apply 
continuously. Consistent with Sierra Club, the EPA is proposing to 
revise standards in this rule to apply at all times.
5. 40 CFR 63.9020 Performance Testing
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in column 3 to a 
``no.'' Section 63.7(e)(1) describes performance testing requirements. 
The EPA is instead proposing to add a performance testing requirement 
at 40 CFR 63.9020(a)(3). The performance testing requirements we are 
proposing to add differ from the General Provisions performance testing 
provisions in several respects. Specifically, the new proposed 
performance testing requirements do not include the language in 40 CFR 
63.7(e)(1) restating the SSM exemption. However, we are including 
similar language that precludes startup and shutdown periods from being 
considered ``representative'' for purposes of performance testing. As 
provided in 40 CFR 63.7(e)(1), we are including language in 40 CFR 
63.9020(a)(3) providing that performance tests conducted under this 
subpart should not be conducted during malfunctions. This is because 
conditions during malfunctions are often not representative of normal 
operating conditions. The EPA is proposing to add language that 
requires the owner or operator to record the process information that 
is necessary to document operating conditions during the test and 
include in such records an explanation to support that such conditions 
represent normal operation. Section 63.7(e) requires that the owner or 
operator make available upon request by the Administrator such records 
``as may be necessary to determine the condition of the performance 
test,'' but does not specifically require the information to be 
recorded. The regulatory text the EPA is proposing to add to this 
provision builds on that requirement and makes explicit the requirement 
to record the information.
6. Monitoring
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.8(c)(1)(i) and (c)(1)(iii) by changing the ``yes'' 
in column 3 to a ``no.'' The cross-references to the general duty and 
SSM plan requirements in those subparagraphs are not necessary in light 
of the removal of the SSM exemption and other requirements of 40 CFR 
63.8 that require good air pollution control practices (40 CFR 
63.8(c)(1)) and that set out the requirements of a quality control 
program for monitoring equipment (40 CFR 63.8(d)).
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.8(d)(3) by changing the ``yes'' in column 3 to a 
``no.'' The final sentence in 40 CFR 63.8(d)(3) refers to the General 
Provisions' SSM plan requirement which is no longer applicable. The EPA 
is proposing to add to the rule at 40 CFR 63.9005(d)(5) text that is 
identical to 40 CFR 63.8(d)(3) except that the final sentence is 
replaced with the following sentence: ``The program of corrective 
action should be included in the plan required under Sec.  
63.8(d)(2).''
7. 40 CFR 63.9055 Recordkeeping
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(b)(2)(i) by changing the ``yes'' in column 3 to 
a ``no.'' Section 63.10(b)(2)(i) describes the recordkeeping 
requirements during startup and shutdown. These recording provisions 
are no longer necessary because the EPA is proposing that recordkeeping 
and reporting applicable to normal operations will apply during startup 
and shutdown. In the absence of special provisions applicable to 
startup and shutdown, such as a startup and shutdown plan, there is no 
reason to

[[Page 1587]]

retain recordkeeping for startup and shutdown periods separate from the 
requirement that applies during normal operation.
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(b)(2)(ii) by changing the ``yes'' in column 3 to 
a ``no.'' Section 63.10(b)(2)(ii) describes the recordkeeping 
requirements during a malfunction. The EPA is proposing to add such 
requirements to 40 CFR 63.9055. The regulatory text we are proposing to 
add differs from the General Provisions it is replacing; the General 
Provisions require the creation and retention of a record of the 
occurrence and duration of each malfunction of process, air pollution 
control, and monitoring equipment. The EPA is proposing that this 
requirement apply to any failure to meet an applicable standard and is 
requiring that the source record the date, time, and duration of the 
failure rather than the ``occurrence.'' The EPA is also proposing to 
add to 40 CFR 63.9055 a requirement that sources keep records that 
include a list of the affected source or equipment and actions taken to 
minimize emissions, an estimate of the quantity of each regulated 
pollutant emitted over the standard for which the source failed to meet 
the standard, and a description of the method used to estimate the 
emissions. Examples of such methods would include product-loss 
calculations, mass balance calculations, measurements when available, 
or engineering judgment based on known process parameters. The EPA is 
proposing to require that sources keep records of this information to 
ensure that there is adequate information to allow the EPA to determine 
the severity of any failure to meet a standard, and to provide data 
that may document how the source met the general duty to minimize 
emissions when the source has failed to meet an applicable standard.
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(b)(2)(iv) by changing the ``yes'' in column 3 to 
a ``no.'' When applicable, the provision requires sources to record 
actions taken during SSM events when those actions were inconsistent 
with their SSM plan. The requirement is no longer appropriate if the 
EPA finalizes its proposal that SSM plans will no longer be required. 
The requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) 
to record actions to minimize emissions and record corrective actions 
is now applicable in 40 CFR 63.9055.
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(b)(2)(v) by changing the ``yes'' in column 3 to 
a ``no.'' When applicable, the provision requires sources to record 
actions taken during SSM events to show that actions taken were 
consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
8. 40 CFR 63.9050 Reporting
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in column 3 to a 
``no.'' Section 63.10(d)(5) describes the reporting requirements for 
startups, shutdowns, and malfunctions. To replace the General 
Provisions reporting requirement, the EPA is proposing to add reporting 
requirements to 40 CFR 63.9050(c)(5). The replacement language differs 
from the General Provisions requirement in that it eliminates periodic 
SSM reports as a stand-alone report. We are proposing language that 
requires sources that fail to meet an applicable standard at any time 
to report the information concerning such events in the semi-annual 
compliance report already required in 40 CFR 63.9050. We are proposing 
that the report must contain the number, date, time, duration, and the 
cause of such events (including unknown cause, if applicable), a list 
of the affected source or equipment, an estimate of the quantity of 
each regulated pollutant emitted over any emission limit, and a 
description of the method used to estimate the emissions.
    Examples of such methods would include product-loss calculations, 
mass balance calculations, measurements when available, or engineering 
judgment based on known process parameters. The EPA is proposing this 
requirement to ensure that there is adequate information to determine 
compliance, to allow the EPA to determine the severity of the failure 
to meet an applicable standard, and to provide data that may document 
how the source met the general duty to minimize emissions during a 
failure to meet an applicable standard.
    The proposed amendments eliminate the cross reference to 40 CFR 
63.10(d)(5)(i) that contains the description of the previously required 
SSM report format and submittal schedule. These specifications are no 
longer necessary because the events will be reported in otherwise 
required reports with similar format and submittal requirements.
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(d)(5)(ii) by changing the ``yes'' in column 3 to 
a ``no.'' Section 63.10(d)(5)(ii) describes an immediate report for 
startups, shutdown, and malfunctions when a source failed to meet an 
applicable standard, but did not follow the SSM plan. We will no longer 
require owners and operators to report when actions taken during a 
startup, shutdown, or malfunction were not consistent with an SSM plan, 
because plans would no longer be required.
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(c)(15) by changing the ``yes'' in column 3 to a 
``no.'' The EPA is proposing that 40 CFR 63.10(c)(15) no longer apply. 
When applicable, the provision allows an owner or operator to use the 
affected source's SSM plan or records kept to satisfy the recordkeeping 
requirements of the SSM plan, specified in 40 CFR 63.6(e), to also 
satisfy the requirements of 40 CFR 63.10(c)(10) through (12). The EPA 
is proposing to eliminate this requirement because SSM plans would no 
longer be required, and, therefore, 40 CFR 63.10(c)(15) would no longer 
be available to satisfy the requirements of 40 CFR 63.10(c)(10) through 
(12).
9. Electronic Reporting
    Through this proposal, the EPA is proposing that owners and 
operators of HCl production facilities submit electronic copies of 
required performance test reports, performance evaluations, 
notifications of compliance status, site-specific monitoring plans, and 
semiannual compliance reports through the EPA's Central Data Exchange 
(CDX) using the Compliance and Emissions Data Reporting Interface 
(CEDRI). A description of the electronic data submission process is 
provided in the memorandum, Electronic Reporting Requirements for New 
Source Performance Standards (NSPS) and National Emission Standards for 
Hazardous Air Pollutants (NESHAP) Rules, available in Docket ID No. 
EPA-HQ-OAR-2018-0417. The proposed rule requires that performance test 
results collected using test methods that are supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the ERT website \19\ at 
the time of the test be submitted in the format generated through the 
use of the ERT and that other performance test results be submitted in 
portable document format (PDF) using the attachment module of the ERT. 
Similarly, we are proposing that performance evaluation results of 
continuous monitoring systems and other performance evaluation results 
be

[[Page 1588]]

submitted in PDF using the attachment module of the ERT.
---------------------------------------------------------------------------

    \19\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For performance test reports, performance evaluations, and 
semiannual compliance reports, the proposed rule requires that owners 
and operators submit information to CEDRI using the appropriate 
spreadsheet template. A draft version of the proposed templates for 
these reports is included in the docket for this rulemaking.\20\ The 
EPA specifically requests comment on the content, layout, and overall 
design of the templates.
---------------------------------------------------------------------------

    \20\ See Electronic Reporting Templates for Hydrochloric Acid 
Production, Subpart NNNNN, available at Docket ID No. EPA-HQ-OAR-
2018-0417.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. In both 
circumstances, the decision to accept the claim of needing additional 
time to report is within the discretion of the Administrator, and 
reporting should occur as soon as possible. The EPA is providing these 
potential extensions to protect owners and operators from noncompliance 
in cases where they cannot successfully submit a report by the 
reporting deadline for reasons outside of their control. First, the 
situation where an extension may be warranted due to outages of the 
EPA's CDX or CEDRI, which precludes an owner or operator from accessing 
the system and submitting required reports, is addressed in 40 CFR 
63.9050(m). Second, 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 an owner or operator from complying with the 
requirement to submit a report electronically as required by this rule, 
is addressed in 40 CFR 63.9050(n). Examples of such events are acts of 
nature, acts of war or terrorism, or equipment failure or safety 
hazards beyond the control of the facility.
    The electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends in data availability and 
transparency, will further assist in the protection of public health 
and the environment, will improve compliance by facilitating the 
ability of regulated facilities to demonstrate compliance with 
requirements and by facilitating the ability of delegated state, local, 
tribal, and territorial air agencies and the EPA to assess and 
determine compliance, and will ultimately reduce burden on regulated 
facilities, delegated air agencies, and the EPA. Electronic reporting 
also eliminates paper-based, manual processes, thereby saving time and 
resources, simplifying data entry, eliminating redundancies, minimizing 
data reporting errors, and providing data quickly and accurately to the 
affected facilities, air agencies, the EPA, and the public. Moreover, 
electronic reporting is consistent with the EPA's plan \21\ to 
implement Executive Order 13563 and is in keeping with the EPA's 
agency-wide policy \22\ developed in response to the White House's 
Digital Government Strategy.\23\ For more information on the benefits 
of electronic reporting, see the memorandum, Electronic Reporting 
Requirements for New Source Performance Standards (NSPS) and National 
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, 
available in Docket ID No. EPA-HQ-OAR-2018-0417.
---------------------------------------------------------------------------

    \21\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \22\ 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.
    \23\ 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.
---------------------------------------------------------------------------

E. What compliance dates are we proposing?

    The EPA is proposing that existing affected sources and affected 
sources that commenced construction or reconstruction on or before 
February 4, 2019 must comply with all of the amendments no later than 
180 days after the effective date of the final rule. The final action 
is not expected to be a ``major rule'' as defined by 5 U.S.C. 804(2), 
so the effective date of the final rule will be the promulgation date 
as specified in CAA section 112(d)(10). For existing sources, we are 
proposing a change that would impact ongoing compliance requirements 
for 40 CFR part 63, subpart NNNNN. As discussed elsewhere in this 
preamble, we are proposing to change the requirements for SSM by 
removing the exemption from the requirements to meet the standard 
during SSM periods and by removing the requirement to develop and 
implement an SSM plan. Our experience with similar industries shows 
that this sort of regulated facility generally requires a time period 
of 180 days to read and understand the amended rule requirements; to 
evaluate their operations to ensure that they can meet the standards 
during periods of startup and shutdown as defined in the rule and make 
any necessary adjustments; and to update their operations to reflect 
the revised requirements. From our assessment of the timeframe needed 
for compliance with the revised requirements, the EPA considers a 
period of 180 days to be the most expeditious compliance period 
practicable, and, thus, is proposing that existing affected sources be 
in compliance with this regulation's revised requirements within 180 
days of the regulation's effective date. We solicit comment on this 
proposed compliance period, and we specifically request submission of 
information from sources in this source category regarding specific 
actions that would need to be undertaken to comply with the proposed 
amended requirements, including the proposed amendments related to 
recordkeeping and reporting and the time needed to make the adjustments 
for compliance with them. We note that information provided may result 
in changes to the proposed compliance date. Affected sources that 
commence construction or reconstruction after February 4, 2019 must 
comply with all requirements of the subpart, including the amendments 
being proposed, no later than the effective date of the final rule or 
upon startup, whichever is later. All affected facilities would have to 
continue to meet the current requirements of 40 CFR part 63, subpart 
NNNNN, until the applicable compliance date of the amended rule.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    We anticipate that 19 HCl production facilities currently operating 
in the United States will be affected by these proposed amendments. The 
basis for our estimate of affected facilities are provided in the 
memorandum, Industry Characterization for the Hydrochloric Acid 
Production NESHAP Residual Risk and Technology Review, which is 
available in the docket for this action. We are not currently aware of 
any planned or potential new or reconstructed HCl production 
facilities.

B. What are the air quality impacts?

    We do not anticipate that the proposed amendments to this subpart 
will impact air quality. We are not proposing changes to the standard 
that

[[Page 1589]]

will result in additional emission reductions beyond the levels already 
achieved by the NESHAP.

C. What are the cost impacts?

    The cost impacts from these proposed amendments are savings in 
costs to affected production facilities. One way to present cost 
estimates is in present value (PV terms). The PV for these proposed 
amendments is equal to a savings of $84,514 at a discount rate of 3 
percent and a savings of $62,136 at a discount rate of 7 percent, 
discounted to 2016. The equivalent annualized value, which is an 
annualized value consistent with the PV estimates, is equal to $22,736 
at a discount rate of 3 percent and $18,344 at a discount rate of 7 
percent (2016 dollars). These calculations are documented in the 
Economic Impact Analysis for the Proposed HCl Production RTR, which is 
available in the docket for this rulemaking.

D. What are the economic impacts?

    With cost savings occurring for affected facilities, we do not 
anticipate the proposed amendments to yield adverse economic impacts, 
including negative impacts on employment.

E. What are the benefits?

    As discussed above, we do not anticipate the proposed amendments to 
this subpart to impact air quality. The electronic submittal of the 
reports addressed in this proposed rulemaking will increase the 
usefulness of the data contained in those reports, is in keeping with 
current trends in data availability and transparency, will further 
assist in the protection of public health and the environment, will 
improve compliance by facilitating the ability of regulated facilities 
to demonstrate compliance with requirements and by facilitating the 
ability of delegated state, local, tribal, and territorial air agencies 
and the EPA to assess and determine compliance, and will ultimately 
reduce burden on regulated facilities, delegated air agencies, and the 
EPA. Electronic reporting also eliminates paper-based, manual 
processes, thereby saving time and resources, simplifying data entry, 
eliminating redundancies, minimizing data reporting errors, and 
providing data quickly and accurately to the affected facilities, air 
agencies, the EPA, and the public.

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.
    Prior to publication of this proposal, Dow Chemical submitted 
several suggestions for changes to the HCl Production NESHAP. Most of 
these changes relate to monitoring, recordkeeping, and reporting 
requirements. The correspondence from Dow,\24\ including their 
suggested regulatory language, are available in the docket for this 
action. We are specifically seeking comment on one issue raised by Dow 
in their May 30, 2018, correspondence, which is available in the docket 
for this action. Dow states that a definition for ``maintenance vents'' 
should be added to the rule if the exemptions for periods of SSM are 
removed.\25\ Dow claims that regular maintenance activities require 
opening equipment after the equipment is cleaned and purged, presumably 
during periods that the equipment is being shut down which would 
previously be exempt from the emissions limits, and that these 
activities that only emit to the atmosphere during periods of 
maintenance or inspection would become subject to the requirements of 
the NESHAP if the exemption is removed. Dow recommends that certain 
emission points that exist due solely to maintenance and inspection of 
equipment be defined as maintenance vents and that EPA set work 
practice standards that require thoroughly purging and degassing the 
equipment to a control device prior to opening it to the atmosphere. 
They submitted recommended regulatory text for the definition of 
``maintenance vent'' and corresponding work practices. We are seeking 
comment on:
---------------------------------------------------------------------------

    \24\ Emails from Russell Wozniak to Nathan Topham, dated May 30, 
2018, and September 24, 2018. Available in the docket for this 
action, Docket ID No. EPA-HQ-OAR-2018-0417.
    \25\ In section IV.D, above, the EPA has proposed to remove the 
SSM exemptions in the HCl Production NESHAP.
---------------------------------------------------------------------------

    <bullet> The necessity of this change for the HCl Production NESHAP 
in light of our proposed removal of the SSM exemptions;
    <bullet> The estimated frequency of these maintenance activities;
    <bullet> The cost associated with making (or not making) this 
change;
    <bullet> The emissions impact of making (or not making) this 
change;
    <bullet> Whether the regulatory language recommended by Dow 
reflects the best performers across the industry; and
    <bullet> Whether it is feasible to set a numerical emission limit 
rather than a work practice standard, as Dow suggests.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR website at https://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 website, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID No. EPA-HQ-OAR-2018-0417 (through the method described in the 
ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility 
(or facilities). We request that all data revision comments be 
submitted in the form of updated Microsoft[supreg] Excel files that are 
generated by the Microsoft[supreg] Access file. These files are 
provided on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.

[[Page 1590]]

VIII. Statutory and Executive Order Reviews

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

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

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

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

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

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to OMB under the PRA. The Information 
Collection Request (ICR) document that the EPA prepared has been 
assigned EPA ICR number 2032.09. You can find a copy of the ICR in the 
docket for this rule, and it is briefly summarized here.
    We are proposing changes to the recordkeeping and reporting 
requirements associated with 40 CFR part 63, subpart NNNNN, in the form 
of eliminating the SSM plan and reporting requirements and adding 
electronic reporting.
    Respondents/affected entities: The respondents to the recordkeeping 
and reporting requirements are owners or operators of facilities that 
produce HCl subject to 40 CFR part 63, subpart NNNNN.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart NNNNN).
    Estimated number of respondents: Nineteen (19) facilities.
    Frequency of response: Initially and semiannually.
    Total estimated burden: The annual recordkeeping and reporting 
burden for responding facilities to comply with all of the requirements 
in the NESHAP, averaged over the 3 years of this ICR, is estimated to 
be 22,000 hours (per year). These proposed amendments reflect 314 hours 
(per year) in reduced burden to comply with the rule due to the removal 
of SSM recordkeeping/reporting requirements and the addition of 
electronic reporting. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: The annual recordkeeping and reporting cost 
for responding facilities to comply with all of the requirements in the 
NESHAP, averaged over the 3 years of this ICR, is estimated to be 
$2,200,000 (rounded, per year), including $754,000 annualized capital 
or operation and maintenance costs. This results in a decrease of 
$17,000 (rounded, per year) to comply with the proposed amendments to 
the rule.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to <a href="/cdn-cgi/l/email-protection#e8a7a1baa9b79b9d8a85819b9b818786a887858ac68d8798c68f879e"><span class="__cf_email__" data-cfemail="c887819a8997bbbdaaa5a1bbbba1a7a688a7a5aae6ada7b8e6afa7be">[email protected]</span></a>, 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 March 6, 2019. The EPA will respond to any ICR-related 
comments in the final rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. There are no 
small entities among the 14 ultimate parent companies impacted by this 
proposed action given the Small Business Administration small business 
size definition for this industry (1,000 employees or greater for NAICS 
325180), and no significant economic impact on any of these entities.

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 
HCl production processes 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.A and IV.A and B of this preamble.

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

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

J. National Technology Transfer and Advancement Act (NTTAA)

    This action involves technical standards. Therefore, the EPA 
conducted a search to identify potentially applicable voluntary 
consensus standards. However, the Agency identified no such standards. 
A thorough summary of the search conducted and results are included in 
the memorandum titled Voluntary Consensus Standard Results for 
Hydrochloric Acid Production Residual Risk and Technology Review, which 
is available 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 (59 FR 7629, February 16, 1994). The 
documentation for this decision is contained in section IV.A.6 of this 
preamble and the technical report, Hydrochloric Acid Production

[[Page 1591]]

Demographic Analysis, which is available in the docket for this action.

List of Subjects in 40 CFR Part 63

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

    Dated: December 20, 2018.
Andrew R. Wheeler,
Acting Administrator.

    For the reasons stated in the preamble, the EPA 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 NNNNN--National Emission Standards for Hazardous Air 
Pollutants for Hydrochloric Acid Production

0
2. Section 63.8985 is amended by revising paragraph (f) to read as 
follows:


Sec.  63.8985  Am I subject to this subpart?

* * * * *
    (f) An HCl production facility is not subject to this subpart if 
all of the gaseous streams containing HCl and chlorine (Cl<INF>2</INF>) 
from HCl process vents, HCl storage tanks, and HCl transfer operations 
are recycled or routed to another process for process purpose, prior to 
being discharged to the atmosphere.
0
3. Section 63.9005 is amended by revising paragraphs (a)-(c) and 
(d)(4)-(6) to read as follows:


Sec.  63.9005  What are my general requirements for complying with this 
subpart?

    (a) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, you must be in 
compliance with the emission limitations and work practice standards in 
this subpart at all times, except during periods of startup, shutdown, 
and malfunction. After [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE 
IN THE FEDERAL REGISTER], for each such source you must be in 
compliance with the emission limitations in this subpart at all times. 
For new and reconstructed sources for which construction or 
reconstruction commenced after February 4, 2019, you must be in 
compliance with the emissions limitations in this subpart at all times.
    (b) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, you must always 
operate and maintain your affected source, including air pollution 
control and monitoring equipment, according to the provisions in Sec.  
63.6(e)(1)(i). After [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE IN 
THE FEDERAL REGISTER] for each such source, and after [DATE OF 
PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] for new and 
reconstructed sources for which construction or reconstruction 
commenced after February 4, 2019, at all times you 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 you 
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 which may include, but is not limited to, monitoring 
results, review of operation and maintenance procedures, review of 
operation and maintenance records, and inspection of the source.
    (c) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, you must develop a 
written startup, shutdown, and malfunction plan according to the 
provisions in Sec.  63.6(e)(3). For each such source, a startup, 
shutdown, and malfunction plan is not required after [DATE 180 DAYS 
AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER]. No startup, 
shutdown, and malfunction plan is required for any new or reconstructed 
source for which construction or reconstruction commenced after 
February 4, 2019.
    (d) * * *
    (4) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, ongoing operation 
and maintenance (O&M) procedures in accordance with the general 
requirements of Sec. Sec.  63.8(c)(1), (3), (4)(ii), (7), and (8), and 
63.9025. After [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER] for each such source, and after [DATE OF PUBLICATION 
OF FINAL RULE IN THE FEDERAL REGISTER] for new and reconstructed 
sources for which construction or reconstruction commenced after 
February 4, 2019, ongoing operation and maintenance (O&M) procedures in 
accordance with the general requirements of Sec. Sec.  63.8(c)(1)(ii), 
(3), (4)(ii), (7), and (8), and 63.9025.
    (5) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, ongoing data quality 
assurance procedures in accordance with the general requirements of 
Sec.  63.8(d). After [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE IN 
THE FEDERAL REGISTER] for each such source, and after [DATE OF 
PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] for new and 
reconstructed sources for which construction or reconstruction 
commenced after [February 4, 2019, ongoing data quality assurance 
procedures in accordance with the general requirements of Sec.  63.8(d) 
except for the requirements related to startup, shutdown, and 
malfunction plans referenced in Sec.  63.8(d)(3). The owner or operator 
shall keep these written procedures on record for the life of the 
affected source or until the affected source is no longer subject to 
the provisions of this part, to be made available for inspection, upon 
request, by the Administrator. If the performance evaluation plan is 
revised, the owner or operator shall keep previous (i.e., superseded) 
versions of the performance evaluation plan on record to be made 
available for inspection, upon request, by the Administrator, for a 
period of 5 years after each revision to the plan. The program of 
corrective action should be included in the plan required under Sec.  
63.8(d)(2).

[[Page 1592]]

    (6) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, ongoing 
recordkeeping and reporting procedures in accordance with the general 
requirements of Sec.  63.10(c) and (e)(1) and (2)(i). After [DATE 180 
DAYS AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] for each 
such source, and after [DATE OF PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER] for new and reconstructed sources for which 
construction or reconstruction commenced after February 4, 2019, 
ongoing recordkeeping and reporting procedures in accordance with the 
general requirements of Sec.  63.10(c)(1) through (c)(14), and (e)(1) 
and (2)(i).
0
4. Section 63.9020 is amended by revising paragraphs (a)(2) and (a)(3) 
to read as follows:


Sec.  63.9020  What performance tests and other procedures must I use?

    (a) * * *
    (2) Before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], for each existing source, and for each new or 
reconstructed source for which construction or reconstruction commenced 
after April 17, 2003, but before February 5, 2019, you must conduct 
each performance test under representative conditions according to the 
requirements in Sec.  63.7(e)(1) and under the specific conditions that 
this subpart specifies in Table 3. After [DATE 180 DAYS AFTER 
PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] for each such 
source, and after [DATE OF PUBLICATION OF FINAL RULE IN THE FEDERAL 
REGISTER] for new and reconstructed sources for which construction or 
reconstruction commenced after February 4, 2019, you must conduct each 
performance test under conditions representative of normal operations. 
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.
    (3) You may not conduct performance tests during periods of 
startup, shutdown, or malfunction.
* * * * *
0
5. Section 63.9025 is amended by revising paragraph (a)(3) to read as 
follows:


Sec.  63.9025  What are my monitoring installation, operation, and 
maintenance requirements?

    (a) * * *
    (3) For at least 75 percent of the operating hours in a 24-hour 
period, you must have valid data (as defined in your site-specific 
monitoring plan) for at least 4 equally spaced periods each hour.
* * * * *
0
6. Section 63.9030 is amended by revising paragraph (c) to read as 
follows:


Sec.  63.9030  How do I demonstrate initial compliance with the 
emission limitations and work practice standards?

* * * * *
    (c) For existing sources and for new or reconstructed sources which 
commenced construction or reconstruction after April 17, 2003, but 
before February 5, 2019, before [DATE 181 DAYS AFTER PUBLICATION OF 
FINAL RULE IN THE FEDERAL REGISTER], You must submit the Notification 
of Compliance Status containing the results of the initial compliance 
demonstration according to the requirements in Sec.  63.9045(f)-(g). 
After [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL 
REGISTER] for such sources, and after [DATE OF PUBLICATION OF FINAL 
RULE IN THE FEDERAL REGISTER] for new or reconstructed sources which 
commence construction or reconstruction after February 4, 2019, you 
must submit the Notification of Compliance Status containing the 
results of the initial compliance demonstration according to the 
requirements in Sec.  63.9045(f)-(g) and Sec.  63.9050(d).
0
7. Section 63.9040 is amended by revising paragraph (e) to read as 
follows:


Sec.  63.9040  How do I demonstrate continuous compliance with the 
emission limitations and work practice standards?

* * * * *
    (e) For existing sources and for new or reconstructed sources which 
commenced construction or reconstruction after April 17, 2003, but 
before February 5, 2019, before [DATE 181 DAYS AFTER PUBLICATION OF 
FINAL RULE IN THE FEDERAL REGISTER], consistent with Sec. Sec.  63.6(e) 
and 63.7(e)(1), deviations that occur during a period of startup, 
shutdown, or malfunction are not violations if you demonstrate to the 
Administrator's satisfaction that you were operating in accordance with 
Sec.  63.6(e)(1). The Administrator will determine whether deviations 
that occur during a period of startup, shutdown, or malfunction are 
violations, according to the provisions in Sec.  63.6(e). After [DATE 
180 DAYS AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] for 
such sources, and after [DATE OF PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER] for new and reconstructed sources which commence 
construction or reconstruction after February 4, 2019, the exemptions 
for periods of startup, shutdown, and malfunction in Sec.  63.6(e) no 
longer apply.
0
8. Section 63.9045 is amended by revising paragraph (f) to read as 
follows:


Sec.  63.9045  What notifications must I submit and when?

* * * * *
    (f) You must submit the Notification of Compliance Status, 
including the performance test results, within 180 calendar days after 
the applicable compliance dates specified in Sec.  63.8995.
* * * * *
0
9. Section 63.9050 is amended by revising paragraphs (a), (c)(4), 
(c)(5), (d) introductory text, (f) introductory text and adding 
paragraphs (g) through (n).


Sec.  63.9050  What reports must I submit and when?

    (a) You must submit a compliance report that includes the 
information in Sec.  63.9050(c) through (e), as applicable, as 
specified in Table 6 to this subpart.
* * * * *
    (c) * * *
    (4) For existing sources and for new or reconstructed sources for 
which construction or reconstruction commenced after April 17, 2003, 
but before February 5, 2019, before [DATE 181 DAYS AFTER PUBLICATION OF 
FINAL RULE IN THE FEDERAL REGISTER], if you had a startup, shutdown, or 
malfunction during the reporting period and you took actions consistent 
with your startup, shutdown, and malfunction plan, the compliance 
report must include the information in Sec.  63.10(d)(5)(i). A startup, 
shutdown, and malfunction plan and the information in Sec.  
63.10(d)(5)(i) is not required after [DATE 180 DAYS AFTER PUBLICATION 
OF FINAL RULE IN THE FEDERAL REGISTER].
    (5) For existing sources and for new or reconstructed sources which 
commenced construction or reconstruction after April 17, 2003, but 
before February 5, 2019, before [DATE 181 DAYS AFTER PUBLICATION OF

[[Page 1593]]

FINAL RULE IN THE FEDERAL REGISTER], if there are no deviations from 
any emission limitations that apply to you, a statement that there were 
no deviations from the emission limitations during the reporting 
period.
* * * * *
    (d) For each deviation from an emission limitation occurring at an 
affected source where you are using a CMS to comply with the emission 
limitation in this subpart, you must include the information in 
paragraphs (c)(1) through (6) of this section and the following 
information in paragraphs (d)(1) through (9) of this section and Sec.  
63.10(e)(3)(vi). This includes periods of startup, shutdown, and 
malfunction.
* * * * *
    (f) For existing sources and for new or reconstructed sources which 
commenced construction or reconstruction after April 17, 2003, but 
before February 5, 2019, before [DATE 181 DAYS AFTER PUBLICATION OF 
FINAL RULE IN THE FEDERAL REGISTER], for each startup, shutdown, or 
malfunction during the reporting period that is not consistent with 
your startup, shutdown, and malfunction plan you must submit an 
immediate startup, shutdown and malfunction report. Unless the 
Administrator has approved a different schedule for submission of 
reports under Sec.  63.10(a), you must submit each report according to 
paragraphs (f)(1) and (2) of this section. An immediate startup, 
shutdown, and malfunction report is not required after [DATE 180 DAYS 
AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER].
* * * * *
    (g) Within 60 days after the date of completing each performance 
test required by this subpart, you must submit the results of the 
performance test following the procedures specified in paragraphs 
(g)(1) through (3) of this section.
    (1) Data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT website 
(https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. Submit the results of the 
performance test to the EPA via the Compliance and Emissions Data 
Reporting Interface (CEDRI). CEDRI can be accessed through the EPA's 
Central Data Exchange (CDX) (https://cdx.epa.gov/). The data must be 
submitted in a file format generated through the use of the EPA's ERT. 
Alternatively, you may submit an electronic file consistent with the 
extensible markup language (XML) schema listed on the EPA's ERT 
website.
    (2) Data collected using test methods that are not supported by the 
EPA's ERT as listed on the EPA's ERT website at the time of the test. 
Submit the results of the performance test as an attachment in the ERT.
    (3) Confidential business information (CBI). If you claim some of 
the information submitted under paragraph (a)(1) is CBI, you must 
submit a complete file, including information claimed to be CBI, to the 
EPA. The file must be generated through the use of the EPA's ERT or an 
alternate electronic file consistent with the XML schema listed on the 
EPA's ERT website. Submit the file on a compact disc, flash drive or 
other commonly used electronic storage medium and clearly mark the 
medium as CBI. Mail the electronic medium to U.S. EPA/OAQPS/CORE CBI 
Office, Attention: Group Leader, Measurement Policy Group, MD C404-02, 
4930 Old Page Rd., Durham, NC 27703. The same file with the CBI omitted 
must be submitted to the EPA via the EPA's CDX as described in 
paragraph (a)(1) of this section.
    (h) Within 60 days after the date of completing each continuous 
monitoring system (CMS) performance evaluation (as defined in Sec.  
63.2), you must submit the results of the performance evaluation 
following the procedures specified in paragraphs (h)(1) through (3) of 
this section.
    (1) Performance evaluations of CMS measuring relative accuracy test 
audit (RATA) pollutants that are supported by the EPA's ERT as listed 
on the EPA's ERT website at the time of the evaluation. Submit the 
results of the performance evaluation to the EPA via CEDRI, which can 
be accessed through the EPA's CDX. The data must be submitted in a file 
format generated through the use of the EPA's ERT. Alternatively, you 
may submit an electronic file consistent with the XML schema listed on 
the EPA's ERT website.
    (2) Performance evaluations of CMS measuring RATA pollutants that 
are not supported by the EPA's ERT as listed on the EPA's ERT website 
at the time of the evaluation. Submit the results of the performance 
evaluation as an attachment in the ERT.
    (3) Confidential business information (CBI). If you claim some of 
the information submitted under paragraph (a)(1) is CBI, you must 
submit a complete file, including information claimed to be CBI, to the 
EPA. The file must be generated through the use of the EPA's ERT or an 
alternate electronic file consistent with the XML schema listed on the 
EPA's ERT website. Submit the file on a compact disc, flash drive or 
other commonly used electronic storage medium and clearly mark the 
medium as CBI. Mail the electronic medium to U.S. EPA/OAQPS/CORE CBI 
Office, Attention: Group Leader, Measurement Policy Group, MD C404-02, 
4930 Old Page Rd., Durham, NC 27703. The same file with the CBI omitted 
must be submitted to the EPA via the EPA's CDX as described in 
paragraph (a)(1) of this section.
    (i) You must submit to the Administrator compliance reports. 
Beginning on [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], submit all subsequent reports following the 
procedure specified in paragraph (l) of this section.
    (j) You must submit to the Administrator performance evaluations. 
Beginning on [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], submit all subsequent reports following the 
procedure specified in paragraph (l) of this section.
    (k) You must submit to the Administrator a Notification of 
Compliance Status. Beginning on [DATE 181 DAYS AFTER PUBLICATION OF 
FINAL RULE IN THE FEDERAL REGISTER], submit all subsequent reports 
following the procedure specified in paragraph (l) of this section.
    (l) If you are required to submit reports following the procedure 
specified in this paragraph, you must submit reports to the EPA via 
CEDRI. CEDRI can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). You must use the appropriate electronic 
report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-reporting-interface-cedri) for this subpart. The date report templates become 
available will be listed on the CEDRI website. The report must be 
submitted by the deadline specified in this subpart, regardless of the 
method in which the report is submitted. If you claim some of the 
information required to be submitted via CEDRI is confidential business 
information (CBI), submit a complete report, including information 
claimed to be CBI, to the EPA. The report must be generated using the 
appropriate form on the CEDRI website. Submit the file on a compact 
disc, flash drive, or other commonly used electronic storage medium and 
clearly mark the medium as CBI. Mail the electronic medium to U.S. EPA/
OAQPS/CORE CBI Office, Attention: Group Leader, Measurement

[[Page 1594]]

Policy Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same 
file with the CBI omitted must be submitted to the EPA via the EPA's 
CDX as described earlier in this paragraph.
    (m) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX, you may assert a claim of EPA system outage for 
failure to timely comply with the reporting requirement. To assert a 
claim of EPA system outage, you must meet the requirements outlined in 
paragraphs (m)(1) through (7) of this section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning 5 business days prior to the date that the submission is due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or caused a delay 
in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date, time and length of the outage;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) Measures taken or to be taken to minimize the delay in 
reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (n) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX, you may assert a claim of force majeure for 
failure to timely comply with the reporting requirement. To assert a 
claim of force majeure, you must meet the requirements outlined in 
paragraphs (n)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning 5 business days prior to 
the date the submission is due. For the purposes of this section, a 
force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or caused a delay 
in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) Measures taken or to be taken to minimize the delay in 
reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
0
10. Section 63.9055 is amended by revising paragraph (b)(1) and adding 
paragraphs (c) and (d).


Sec.  63.9055  What records must I keep?

* * * * *
    (b) * * *
    (1) For existing sources and for new or reconstructed sources which 
commenced construction or reconstruction after April 17, 2003, but 
before February 5, 2019, before [DATE 180 DAYS AFTER PUBLICATION OF 
FINAL RULE IN THE FEDERAL REGISTER], the records in Sec.  
63.6(e)(3)(iii) through (v) related to startup, shutdown, and 
malfunction. for a period of five years. A startup, shutdown, and 
malfunction plan is not required after [DATE 180 DAYS AFTER PUBLICATION 
OF FINAL RULE IN THE FEDERAL REGISTER].
* * * * *
    (c) After [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE IN THE 
FEDERAL REGISTER], you must keep records of each deviation specified in 
paragraphs (c)(1) through (3) of this section.
    (1) For each deviation record the date, time and duration of each 
deviation.
    (2) For each deviation, record and retain a list of the affected 
sources or equipment, an estimate of the quantity of each regulated 
pollutant emitted over any emission limit and a description of the 
method used to estimate the emissions.
    (3) Record actions taken to minimize emissions in accordance with 
63.9005(b), and any corrective actions taken to return the affected 
unit to its normal or usual manner of operation.
    (d) 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
11. Table 1 to subpart NNNNN of part 63 is amended by correcting a 
typographical error in entry 2.

 Table 1 to Subpart NNNNN of Part 63--Emission Limits and Work Practice
                                Standards
                              * * * * * * *
------------------------------------------------------------------------
                                           You must meet the following
             For each . . .                  emission limit and work
                                                practice standard
------------------------------------------------------------------------
 
                              * * * * * * *
2. Emission stream from an HCl storage   Reduce HCl emissions by 99
 tank at an existing source.              percent or greater or achieve
                                          an outlet concentration of 120
                                          ppm by volume or less.
 
                              * * * * * * *
------------------------------------------------------------------------


[[Page 1595]]

0
12. Revise table 6 of subpart NNNNN of part 63 to read as follows:

Table 6 to Subpart NNNNN of Part 63--Requirements for Reports

    As stated in Sec.  63.9050(a), you must submit a compliance report 
that includes the information in Sec.  63.9050(c) through (e) as well 
as the information in the following table. For existing sources and for 
new or reconstructed sources which commenced construction or 
reconstruction after April 17, 2003, but before February 5, 2019, 
before [DATE 181 DAYS AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL 
REGISTER], you must also submit startup, shutdown, and malfunction 
(SSM) reports according to the requirements in Sec.  63.9050(f) and the 
following. A startup, shutdown, and malfunction plan is not required 
after [DATE 180 DAYS AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL 
REGISTER].

------------------------------------------------------------------------
                                          Then you must submit a report
                If . . .                        or statement that:
------------------------------------------------------------------------
1. There are no deviations from any      There were no deviations from
 emission limitations that apply to you.  any emission limitations that
                                          apply to you during the
                                          reporting period. Include this
                                          statement in the compliance
                                          report.
2. There were no periods during which    There were no periods during
 the operating parameter monitoring       which the CMS were out-of-
 systems were out-of-control in           control during the reporting
 accordance with the monitoring plan.     period. Include this statement
                                          in the compliance report.
3. There was a deviation from any        Contains the information in
 emission limitation during the           Sec.   63.9050(d). Include
 reporting period.                        this statement in the
                                          compliance report.
4. There were periods during which the   Contains the information in
 operating parameter monitoring systems   Sec.   63.9050(d). Include
 were out-of-control in accordance with   this statement in the
 the monitoring plan.                     compliance report.
5. There was a SSM during the reporting  For existing sources and for
 period that is not consistent with       new or reconstructed sources
 your SSM plan.                           which commenced construction
                                          or reconstruction after April
                                          17, 2003, but before February
                                          5, 2019, before [DATE 181 DAYS
                                          AFTER PUBLICATION OF FINAL
                                          RULE IN THE FEDERAL REGISTER],
                                          contains the information in
                                          Sec.   63.9050(f). Include
                                          this statement in the
                                          compliance report. A startup,
                                          shutdown, and malfunction plan
                                          is not required after [DATE
                                          180 DAYS AFTER PUBLICATION OF
                                          FINAL RULE IN THE FEDERAL
                                          REGISTER].
6. There were periods when the           Contains the information in
 procedures in the LDAR plan were not     Sec.   63.9050(c)(7). Include
 followed.                                this statement in the
                                          compliance report.
------------------------------------------------------------------------

0
13. Table 7 to subpart NNNNN of part 63 is amended by:
0
a. Removing the entry ``Sec.  63.6(e)(1)-(2)'';
0
b. Adding the entries ``Sec.  63.6(e)(1)(i)'', ``Sec.  
63.6(e)(1)(ii)'', and ``Sec.  63.6(e)(1)(iii)-(e)(2)'' in numerical 
order;
0
c. Revising the entry ``Sec.  63.6(e)(3)'';
0
d. Revising the entry ``Sec.  63.6(f)(1)'';
0
e. Revising the entry ``Sec.  63.7(e)(1)'';
0
f. Removing the entry ``Sec.  63.8(c)(1)-(3)'';
0
g. Adding the entries ``Sec.  63.8(c)(1)(i)'', ``Sec.  
63.8(c)(1)(ii)'', ``Sec.  63.8(c)(1)(iii)'', and ``Sec.  63.8(c)(2)-
(3)'' in numerical order;
0
h. Removing the entry ``Sec.  63.8(d)-(e)'';
0
i. Adding the entries ``Sec.  63.8(d)(1)-(2)'', ``Sec.  63.8(d)(3)'', 
and ``Sec.  63.8(e)'' in numerical order;
0
j. Removing the entry ``Sec.  63.10(b)(2)(i)-(xi)'';
0
k. Adding the entries ``Sec.  63.10(b)(2)(i)-(ii)'', ``Sec.  
63.10(b)(2)(iii)'', ``Sec.  63.10(b)(2)(iv)'', ``Sec.  
63.10(b)(2)(v)'', ``Sec.  63.10(b)(2)(vi)'', and ``Sec.  
63.10(b)(2)(vii)-(xi)'' in numerical order;
0
l. Removing the entry ``Sec.  63.10(c)'';
0
m. Adding the entries ``Sec.  63.10(c)(1)-(14)'' and ``Sec.  
63.10(c)(15'' in numerical order; and
0
n. Revising the entry ``Sec.  63.10(d)(5)'';
    The revisions and additions read as follows:

            Table 7 to Subpart NNNNN of Part 63--Applicability of General Provisions to Subpart NNNNN
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
              Citation                      Requirement        Applies to subpart NNNNN        Explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Sec.   63.6(e)(1)(i)...............  General Duty to minimize  No, for new or            Subpart NNNNN requires
                                      emissions.                reconstructed sources     affected units to meet
                                                                which commenced           emissions standards at
                                                                construction or           all times. See Sec.
                                                                reconstruction after      63.9005(b) for general
                                                                February 4, 2019. Yes,    duty requirement.
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.6(e)(1)(ii)..............  Requirement to correct    No, for new or
                                      malfunctions ASAP.        reconstructed sources
                                                                which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.6(e)(1)(iii)-(e)(2)......  Operation and             Yes.....................
                                      maintenance
                                      requirements.

[[Page 1596]]

 
Sec.   63.6(e)(3)..................  SSM plans...............  No, for new or
                                                                reconstructed sources
                                                                which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.6(f)(1)..................  Compliance except during  No, for new or
                                      SSM.                      reconstructed sources
                                                                which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
 
                                                  * * * * * * *
Sec.   63.7(e)(1)..................  Conditions for            No, for new or            See Sec.   63.9020(a)
                                      conducting performance    reconstructed sources     for performance
                                      tests.                    which commenced           testing requirements.
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
 
                                                  * * * * * * *
Sec.   63.8(c)(1)(i)...............  General duty to minimize  No, for new or
                                      emissions and CMS         reconstructed sources
                                      operation.                which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.8(c)(1)(ii)..............  Continuous monitoring     Yes.....................  Applies as modified by
                                      system O&M.                                         Sec.   63.9005(d).
Sec.   63.8(c)(1)(iii).............  Requirement to develop    No, for new or
                                      SSM Plan for CMS.         reconstructed sources
                                                                which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.8(c)(2)-(3)..............  Continuous monitoring     Yes.....................  Applies as modified by
                                      system O&M.                                         Sec.   63.9005(d).
 
                                                  * * * * * * *
Sec.   63.8(d)(1)-(2)..............  Quality control program   Yes.....................  Applies as modified by
                                      and CMS performance                                 Sec.   63.9005(d).
                                      evaluation.
Sec.   63.8(d)(3)..................  Written procedures for    No, for new or            See Sec.
                                      CMS.                      reconstructed sources     63.9005(d)(5) for
                                                                which commenced           written procedures for
                                                                construction or           CMS.
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.8(e).....................  Performance evaluation    Yes.....................  Applies as modified by
                                      of CMS.                                             Sec.   63.9005(d).
 
                                                  * * * * * * *
Sec.   63.10(b)(2)(i)-(ii).........  Records related to SSM    No, for new or            See 63.9055 for
                                      periods.                  reconstructed sources     recordkeeping of (1)
                                                                which commenced           date, time and
                                                                construction or           duration; (2) listing
                                                                reconstruction after      of affected source or
                                                                February 4, 2019. Yes,    equipment, and an
                                                                for all other affected    estimate of the
                                                                sources before [DATE      quantity of each
                                                                181 DAYS AFTER            regulated pollutant
                                                                PUBLICATION OF FINAL      emitted over the
                                                                RULE IN THE FEDERAL       standard; and (3)
                                                                REGISTER], and No         actions to minimize
                                                                thereafter.               emissions and correct
                                                                                          the failure.
Sec.   63.10(b)(2)(iii)............  Maintenance Records.....  Yes.....................

[[Page 1597]]

 
Sec.   63.10(b)(2)(iv).............  Actions taken to          No, for new or
                                      minimize emissions        reconstructed sources
                                      during SSM.               which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.10(b)(2)(v)..............  Actions taken to          No, for new or
                                      minimize emissions        reconstructed sources
                                      during SSM.               which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
Sec.   63.10(b)(2)(vi).............  Recordkeeping for CMS     Yes.....................
                                      malfunctions.
Sec.   63.10(b)(2)(vii)-(xi).......  Records for performance   Yes.....................
                                      tests and CMS.
 
                                                  * * * * * * *
Sec.   63.10(c)(1)-(14)............  Additional recordkeeping  Yes.....................  Applies as modified by
                                      requirements for                                    Sec.   63.9005 (d).
                                      sources with CMS.
Sec.   63.10(c)(15)................  Use of SSM Plan.........  No, for new or
                                                                reconstructed sources
                                                                which commenced
                                                                construction or
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
 
                                                  * * * * * * *
Sec.   63.10(d)(5).................  SSM reports.............  No, for new or            See Sec.
                                                                reconstructed sources     63.9050(c)(5) for
                                                                which commenced           malfunction reporting
                                                                construction or           requirements.
                                                                reconstruction after
                                                                February 4, 2019. Yes,
                                                                for all other affected
                                                                sources before [DATE
                                                                181 DAYS AFTER
                                                                PUBLICATION OF FINAL
                                                                RULE IN THE FEDERAL
                                                                REGISTER], and No
                                                                thereafter.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2018-28322 Filed 2-1-19; 8:45 am]
 BILLING CODE 6560-50-P


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