1570 Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 

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. 

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-sourcesair-pollution/hydrochloric-acidproduction-national-emissionstandards-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: 

• Email: a-and-r-docket@epa.gov. 

Include Docket ID No. EPA–HQ–OAR– 

2018–0417 in the subject line of the 

message. 

• Fax: (202) 566–9744. Attention 

Docket ID No. EPA–HQ–OAR–2018– 

0417. 

• 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. 

• 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: topham.nathan@epa.gov. 

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: 

hollingsworth.terri@epa.gov. 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: 

mia.marcia@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Public hearing. Please contact Adrian 

Gates at (919) 541–4860 or by email at 

gates.adrian@epa.gov to request a 

public hearing, to register to speak at the 

public hearing, or to inquire as to 

whether a public hearing will be held. 

Docket. The EPA has established a 

docket for this rulemaking under Docket 

ID No. EPA–HQ–OAR–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 


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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 

Cl2 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/m3 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 DecisionMaking 

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 


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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 (Cl2) 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

HCl production and fume silica production .......................................................................................... HCl .................................... 325180 

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-nationalemission-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 


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1Although 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. 

2For 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. 

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 twostep 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. 

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 Cl2 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. 

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. 


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3The 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. 

4Recommendations of the SAB RTR Panel are 

provided in their report, which is available at: 

http://yosemite.epa.gov/sab/sabproduct.nsf/ 

4AB3966E263D943A8525771F00668381/$File/EPASAB-10-007-unsigned.pdf. 

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: 

[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

In response to the SAB 

recommendations, the EPA incorporates 


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5U.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. 

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’’: 

• Any add-on control technology or 

other equipment that was not identified 

and considered during development of 

the original MACT standards; 

• Any improvements in add-on 

control technology or other equipment 

(that were identified and considered 

during development of the original 

MACT standards) that could result in 

additional emissions reduction; 

• Any work practice or operational 

procedure that was not identified or 

considered during development of the 

original MACT standards; 

• Any process change or pollution 

prevention alternative that could be 

broadly applied to the industry and that 

was not identified or considered during 

development of the original MACT 

standards; and 

• Any significant changes in the cost 

(including cost effectiveness) of 

applying controls (including controls 

the EPA considered during the 

development of the original MACT 

standards). 

In addition to reviewing the practices, 

processes, and control technologies that 

were considered at the time we 

originally developed the NESHAP, we 

review a variety of data sources in our 

investigation of potential practices, 

processes, or controls to consider. See 

sections II.C and II.D of this preamble 

for information on the specific data 

sources that were reviewed as part of 

the technology review. 

C. How do we estimate post-MACT risk 

posed by the source category? 

In this section, we provide a complete 

description of the types of analyses that 

we generally perform during the risk 

assessment process. In some cases, we 

do not perform a specific analysis 

because it is not relevant. For example, 

in the absence of emissions of HAP 

known to be persistent and 

bioaccumulative in the environment 

(PB–HAP), we would not perform a 

multipathway exposure assessment. 

Where we do not perform an analysis, 

we state that we do not and provide the 

reason. While we present all of our risk 

assessment methods, we only present 

risk assessment results for the analyses 

actually conducted (see section IV.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. 

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 crosssectional 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 MACTallowable 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, 


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6For more information about HEM–3, go to 

https://www.epa.gov/fera/risk-assessment-andmodeling-human-exposure-model-hem. 

7U.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). 

8A census block is the smallest geographic area 

for which census statistics are tabulated. 

9The 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 

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 Cl2. 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 Cl2 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. 

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. 

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 (mg/m3)) 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 doseresponse 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 doseresponse 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-assessinghealth-risks-associated-exposurehazardous-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 


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(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/214C6

E915BB04E14852570CA007A682C/$File/ecadv

02001.pdf. 

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 categoryspecific 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. 

11CalEPA 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-relsummary. 

12National 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). 

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. 

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-hotspots-program-guidance-manualpreparation-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 doseresponse values used to estimate health 

risks are available at https://

www.epa.gov/fera/dose-responseassessment-assessing-health-risksassociated-exposure-hazardous-airpollutants. 

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. 

To characterize the potential health 

risks associated with estimated acute 

inhalation exposures to a HAP, we 

generally use multiple acute doseresponse 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 doseresponse 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/m3 (milligrams per cubic meter)) of 

a substance above which it is predicted 

that the general population, including 

susceptible individuals, could 

experience notable discomfort, 

irritation, or certain asymptomatic 

nonsensory effects. However, the effects 

are not disabling and are transient and 

reversible upon cessation of exposure.’’ 

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. 

ERPGs are ‘‘developed for emergency 

planning and are intended as healthbased guideline concentrations for 


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13ERPGS Procedures and Responsibilities, March 

2014. American Industrial Hygiene Association. 

Available at: https://www.aiha.org/get-involved/ 

AIHAGuidelineFoundation/EmergencyResponse

PlanningGuidelines/Documents/ERPG%20

Committee%20Standard%20Operating

%20Procedures%20%20-%20March%202014

%20Revision%20%28Updated%2010-2- 

2014%29.pdf. 

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. 

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-airtoxics-risk-assessment-referencelibrary). 

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 watercolumn 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-adverseeffect level, and no-observed-adverseeffect 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 


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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 backcalculate 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 wellbeing.’’ 

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 singletier 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 km2; 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 facilitywide 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 


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14 IRIS glossary (https://ofmpub.epa.gov/sor_

internet/registry/termreg/searchandretrieve/ 

glossariesandkeywordlists/search.do?details=&

glossaryName=IRIS%20Glossary). 

15An 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. 

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 facilitywide analyses, including all facilitywide 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 


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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. 

derive dose-response values that are 

intended to protect against appreciable 

risk of deleterious effects. 

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 doseresponse 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

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, 


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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 hourby-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 Cl2. 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) Cancer 

incidence 

(cases 

per year) 

Population 

with cancer 

risk of 1-in-1 

million or more 

Population 

with cancer 

risk of 10-in-1 

million or more 

Max chronic noncancer HI 

Based on actuals (and allowables) 

actual 

emissions 

Based on 

allowable 

emissions 

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 Cl2. 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 Cl2 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 Cl2 emissions from process vents at 

two facilities. Based on allowable 

emissions, 300 people are estimated to 


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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. 

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

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 multipathway 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 


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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/nationalair-toxics-assessment/nata-limitations for a more 

complete discussion. 

(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 costeffective 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 Cl2. 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. 

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 Cl2, 

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, 


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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 offline 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 wellperforming 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 


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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 § 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 


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Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 1587 

19https://www.epa.gov/electronic-reporting-airemissions/electronic-reporting-tool-ert. 

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 productloss 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 


amozie on DSK3GDR082PROD with PROPOSALS3
1588 Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 

20See Electronic Reporting Templates for 

Hydrochloric Acid Production, Subpart NNNNN, 

available at Docket ID No. EPA–HQ–OAR–2018– 

0417. 

21EPA’s Final Plan for Periodic Retrospective 

Reviews, August 2011. Available at: https://

www.regulations.gov/document?D=EPA-HQ-OA2011-0156-0154. 

22E-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/digitalgovernment.html. 

submitted in PDF using the attachment 

module of the 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. 

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 agencywide 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. 

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 


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Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 1589 

24Emails 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. 

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: 

• The necessity of this change for the 

HCl Production NESHAP in light of our 

proposed removal of the SSM 

exemptions; 

• The estimated frequency of these 

maintenance activities; 

• The cost associated with making (or 

not making) this change; 

• The emissions impact of making (or 

not making) this change; 

• Whether the regulatory language 

recommended by Dow reflects the best 

performers across the industry; and 

• 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®

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® Excel 

files that are generated by the 

Microsoft® Access file. These files are 

provided on the RTR website at https:// 

www3.epa.gov/ttn/atw/rrisk/rtrpg.html. 


amozie on DSK3GDR082PROD with PROPOSALS3
1590 Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 

VIII. Statutory and Executive Order 

Reviews 

Additional information about these 

statutes and Executive Orders can be 

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

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action is 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 OIRA_

submission@omb.eop.gov, Attention: 

Desk Officer for the EPA. Since OMB is 

required to make a decision concerning 

the ICR between 30 and 60 days after 

receipt, OMB must receive comments no 

later than 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, lowincome 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 


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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 

■ 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 

■ 2. Section 63.8985 is amended by 

revising paragraph (f) to read as follows: 

§ 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 (Cl2) 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. 

■ 3. Section 63.9005 is amended by 

revising paragraphs (a)–(c) and (d)(4)– 

(6) to read as follows: 

§ 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 

§ 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 § 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 §§ 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 

§§ 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 § 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 

§ 63.8(d) except for the requirements 

related to startup, shutdown, and 

malfunction plans referenced in 

§ 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 

§ 63.8(d)(2). 


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(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 § 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 § 63.10(c)(1) 

through (c)(14), and (e)(1) and (2)(i). 

■ 4. Section 63.9020 is amended by 

revising paragraphs (a)(2) and (a)(3) to 

read as follows: 

§ 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 § 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. 

* * * * * 

■ 5. Section 63.9025 is amended by 

revising paragraph (a)(3) to read as 

follows: 

§ 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. 

* * * * * 

■ 6. Section 63.9030 is amended by 

revising paragraph (c) to read as follows: 

§ 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 § 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 § 63.9045(f)–(g) and 

§ 63.9050(d). 

■ 7. Section 63.9040 is amended by 

revising paragraph (e) to read as follows: 

§ 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 §§ 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 § 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 § 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 § 63.6(e) no longer 

apply. 

■ 8. Section 63.9045 is amended by 

revising paragraph (f) to read as follows: 

§ 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 § 63.8995. 

* * * * * 

■ 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). 

§ 63.9050 What reports must I submit and 

when? 

(a) You must submit a compliance 

report that includes the information in 

§ 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 

§ 63.10(d)(5)(i). A startup, shutdown, 

and malfunction plan and the 

information in § 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 


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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 

§ 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 § 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-airemissions/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 § 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-airemissions/compliance-and-emissionsdata-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 


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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. 

■ 10. Section 63.9055 is amended by 

revising paragraph (b)(1) and adding 

paragraphs (c) and (d). 

§ 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 

§ 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. 

■ 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

*******

For each . . . You must meet the following emission limit and work practice standard 

*******

2. Emission stream from an HCl storage tank at an existing source ...... Reduce HCl emissions by 99 percent or greater or achieve an outlet 

concentration of 120 ppm by volume or less. 

* * * * * * * 


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Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 1595 

■ 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 § 63.9050(a), you must 

submit a compliance report that 

includes the information in § 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 § 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]. 

If . . . Then you must submit a report or statement that: 

1. There are no deviations from any emission limitations that apply to 

you.

There were no deviations from 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 the operating parameter monitoring systems were out-of-control in accordance with the monitoring 

plan.

There were no periods during which the CMS were out-of-control during the reporting period. Include this statement in the compliance report. 

3. There was a deviation from any emission limitation during the reporting period.Contains the information in § 63.9050(d). Include this statement in the 

compliance report. 

4. There were periods during which the operating parameter monitoring 

systems were out-of-control in accordance with the monitoring plan.

Contains the information in § 63.9050(d). Include this statement in the 

compliance report. 

5. There was a SSM during the reporting period that is not consistent 

with your SSM plan.

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], contains the 

information in § 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 procedures in the LDAR plan were not 

followed.

Contains the information in § 63.9050(c)(7). Include this statement in 

the compliance report. 

■ 13. Table 7 to subpart NNNNN of part 

63 is amended by: 

■ a. Removing the entry ‘‘§ 63.6(e)(1)– 

(2)’’; 

■ b. Adding the entries ‘‘§ 63.6(e)(1)(i)’’, 

‘‘§ 63.6(e)(1)(ii)’’, and ‘‘§ 63.6(e)(1)(iii)– 

(e)(2)’’ in numerical order; 

■ c. Revising the entry ‘‘§ 63.6(e)(3)’’; 

■ d. Revising the entry ‘‘§ 63.6(f)(1)’’; 

■ e. Revising the entry ‘‘§ 63.7(e)(1)’’; 

■ f. Removing the entry ‘‘§ 63.8(c)(1)– 

(3)’’; 

■ g. Adding the entries ‘‘§ 63.8(c)(1)(i)’’, 

‘‘§ 63.8(c)(1)(ii)’’, ‘‘§ 63.8(c)(1)(iii)’’, and 

‘‘§ 63.8(c)(2)–(3)’’ in numerical order; 

■ h. Removing the entry ‘‘§ 63.8(d)–(e)’’; 

■ i. Adding the entries ‘‘§ 63.8(d)(1)– 

(2)’’, ‘‘§ 63.8(d)(3)’’, and ‘‘§ 63.8(e)’’ in 

numerical order; 

■ j. Removing the entry 

‘‘§ 63.10(b)(2)(i)–(xi)’’; 

■ k. Adding the entries ‘‘§ 63.10(b)(2)(i)– 

(ii)’’, ‘‘§ 63.10(b)(2)(iii)’’, 

‘‘§ 63.10(b)(2)(iv)’’, ‘‘§ 63.10(b)(2)(v)’’, 

‘‘§ 63.10(b)(2)(vi)’’, and 

‘‘§ 63.10(b)(2)(vii)–(xi)’’ in numerical 

order; 

■ l. Removing the entry ‘‘§ 63.10(c)’’; 

■ m. Adding the entries ‘‘§ 63.10(c)(1)– 

(14)’’ and ‘‘§ 63.10(c)(15’’ in numerical 

order; and 

■ n. Revising the entry ‘‘§ 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 

*******

§ 63.6(e)(1)(i) .............. General Duty to minimize emissions .. 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.

Subpart NNNNN requires affected 

units to meet emissions standards 

at all times. See § 63.9005(b) for 

general duty requirement. 

§ 63.6(e)(1)(ii) ............. Requirement to correct malfunctions 

ASAP.

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.

§ 63.6(e)(1)(iii)–(e)(2) Operation and maintenance requirements.Yes.


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1596 Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 

TABLE 7 TO SUBPART NNNNN OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART NNNNN—Continued 

*******

Citation Requirement Applies to subpart NNNNN Explanation 

§ 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.

§ 63.6(f)(1) .................. Compliance except during SSM ......... 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.

* * * * * * * 

§ 63.7(e)(1) ................. Conditions for conducting performance tests.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.

See § 63.9020(a) for performance 

testing requirements. 

* * * * * * * 

§ 63.8(c)(1)(i) .............. General duty to minimize emissions 

and CMS operation.

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.

§ 63.8(c)(1)(ii) ............. Continuous monitoring system O&M .. Yes ...................................................... Applies as modified by § 63.9005(d). 

§ 63.8(c)(1)(iii) ............ Requirement to develop SSM Plan for 

CMS.

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.

§ 63.8(c)(2)–(3) ........... Continuous monitoring system O&M .. Yes ...................................................... Applies as modified by § 63.9005(d). 

*******

§ 63.8(d)(1)–(2) .......... Quality control program and CMS performance evaluation.Yes ...................................................... Applies as modified by § 63.9005(d). 

§ 63.8(d)(3) ................. Written procedures for CMS ............... 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.

See § 63.9005(d)(5) for written procedures for CMS. 

§ 63.8(e) ..................... Performance evaluation of CMS ......... Yes ...................................................... Applies as modified by § 63.9005(d). 

*******

§ 63.10(b)(2)(i)–(ii) ...... Records related to SSM periods ......... 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.

See 63.9055 for recordkeeping of (1) 

date, time and duration; (2) listing of 

affected source or equipment, and 

an estimate of the quantity of each 

regulated pollutant emitted over the 

standard; and (3) actions to minimize emissions and correct the failure. 

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


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Federal Register / Vol. 84, No. 23 / Monday, February 4, 2019 / Proposed Rules 1597 

TABLE 7 TO SUBPART NNNNN OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART NNNNN—Continued 

*******

Citation Requirement Applies to subpart NNNNN Explanation 

§ 63.10(b)(2)(iv) .......... Actions taken to minimize emissions 

during SSM.

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.

§ 63.10(b)(2)(v) ........... Actions taken to minimize emissions 

during SSM.

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.

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

§ 63.10(b)(2)(vii)–(xi) .. Records for performance tests and 

CMS.

Yes.

* * * * * * * 

§ 63.10(c)(1)–(14) ....... Additional recordkeeping requirements 

for sources with CMS.

Yes ...................................................... Applies as modified by § 63.9005 (d). 

§ 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.

* * * * * * * 

§ 63.10(d)(5) ............... SSM reports ........................................ 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.

See § 63.9050(c)(5) for malfunction 

reporting requirements. 

* * * * * * * 

[FR Doc. 2018–28322 Filed 2–1–19; 8:45 am] 

BILLING CODE 6560–50–P 


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